tag:blogger.com,1999:blog-76517802024-02-07T04:31:20.029+02:0021st Century ManagementAnonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.comBlogger81125tag:blogger.com,1999:blog-7651780.post-66143392865997659942015-05-16T15:39:00.001+03:002015-05-16T15:39:29.747+03:00#NoEstimates Project Planning using Monte Carlo simulation videos<br />
Last year InfoQ published my article <a href="http://www.infoq.com/articles/noestimates-monte-carlo" target="_blank">#NoEstimates Project Planning Using Monte Carlo Simulation</a> on how to plan probabilistically using Reference Class Forecasting and Monte Carlo simulation.<br />
<br />
Probabilistic high-level plan forecasts the initial budget and also the range of the time frame for a project. We don’t plan in detail what is not absolutely necessary to plan. The short-term details, like the scheduling, are done based on the immediate needs and capabilities – and we create these schedules upon the execution of the high-level plan. When executing the high-level plan we have to keep focus on the project intent but we can never be certain which paths will offer the best chances of realizing it. We exploit uncertainty by making a series of small choices which open up further options then observe the effects of our actions and exploit unexpected successes.
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<br />
I presented the topic at Lean Agile Scotland 2014 and at Lean Kanban UK 2014 conferences. The videos are <a href="http://www.infoq.com/presentations/monte-carlo-simulation" target="_blank">here</a> and <a href="https://vimeo.com/107763575" target="_blank">here</a>. Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-74707338675936557722015-04-04T18:14:00.000+03:002015-05-15T08:55:57.894+03:00I am nominated for the 2015 Brickell Key Award!<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: large;">It was a huge surprise when I received the email saying I am nominated for the </span><a href="http://lkna15.leankanban.com/support/" target="_blank"><span style="font-size: large;">2015 Brickell Key Award</span></a><span style="font-size: large;">. The email reads "…nominated due to your exhaustive work in advancing the quality of data-driven planning and spending your time spreading that knowledge worldwide. You deserve it." </span></span><br />
<span style="font-family: Arial; font-size: large;"></span><br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://lkna15.leankanban.com/wp-content/uploads/2015/03/brickell-key-2015-finalist-badge.gif" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-size: large;"><img border="0" src="http://lkna15.leankanban.com/wp-content/uploads/2015/03/brickell-key-2015-finalist-badge.gif" /></span></a><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: large;">First what is the Brickell Key Award? As we can read </span><a href="http://lkna15.leankanban.com/support/" target="_blank"><span style="font-size: large;">here</span></a><span style="font-size: large;"> </span></span><span style="font-family: Arial, Helvetica, sans-serif; font-size: large;"> "The Brickell Key Award highlights excellence in our community, honoring two people who have shown outstanding achievement, leadership and contribution to our community. The award is especially oriented toward highlighting people who are lesser known and worthy of greater exposure." I am “lesser known” indeed…but am I worthy of great exposure? Let’s check…</span></div>
<span style="font-family: Arial, Helvetica, sans-serif; font-size: large;"></span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: large;">First what about “contribution to our community”? Indeed I have some contributions…for instance I am an Accredited Kanban trainer (AKT)...but I don't give many public classes...mostly private classes and of course I use Kanban Method in my own work...also three years ago I published David Anderson’s Kanban book in Bulgarian language…and I even spent eight months translating the first eight chapters myself… before I hired a professional translator who finished the rest of the book in 3 months…but on the other hand I failed to make the Bulgarian translation of the Kanban book a commercial success…which didn’t stop me to publish in Bulgarian for the first time ever two books by W. Edwards Deming and four books by Eli Goldratt…I know the Kanban community honors the two great management gurus and besides “The Goal” is quite successful commercially…unfortunately not as much as it should be…but it takes time an idea to stick with the public…which reminds me of the fact that last year I presented </span><a href="http://www.infoq.com/articles/noestimates-monte-carlo" target="_blank"><span style="font-size: large;">#NoEstimates Project Planning Using Monte Carlo Simulation</span></a><span style="font-size: large;"> at five community conferences…and at the Istanbul event I even managed to make the audience laugh…thanks God not at the math I presented…the math lots of people seems to like…but I am not sure if it is a success…well it helps me in my daily work…but on the other hand nobody ever came to tell me something like – your idea is sound but while using it on a daily basis I found a small gap in it and here is how it can be improved or better explained…I mean somebody to build on my work…like I did on the method for probabilistically planning a project - the one David Anderson presented at </span><a href="http://www.lean-kanban-conference.de/what-happened-2011/predictability-and-measurement-with-kanban/" target="_blank"><span style="font-size: large;">LKCE2011</span></a></span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: large;">... indeed first I published </span><a href="http://www.slideshare.net/dimiterbak/project-planning-ll-v-lkuk13" target="_blank"><span style="font-size: large;">Project Planning using Little’s Law</span></a><span style="font-size: large;">...
</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: large;">that article allowed me to become the first ever Bulgarian to present at a global Theory Of Constraints conference - </span><a href="http://www.tocico.org/?page=2014_speakers" target="_blank"><span style="font-size: large;">TOCICO2014</span></a><span style="font-size: large;">!!!... and I continued using and building on David’s probabilistic project planning method…like in my latest article </span><a href="http://www.infoq.com/articles/probabilistic-project-sizing" target="_blank"><span style="font-size: large;">Probabilistic project sizing using Randomized Branch Sampling (RBS)</span></a><span style="font-size: large;"> … which hopefully will have an impact…it has already earned me a presentation spot at </span><a href="http://lkna15.leankanban.com/program/" target="_blank"><span style="font-size: large;">LKNA15</span></a><span style="font-size: large;"> in Miami…and…and that’s all I could recall about my contribution to the Kanban community…<br />
<br />So if the nomination is not about contribution then what about the “outstanding achievement”? Here comes the difficult part…because now I have to share what David Anderson wrote to me in 2013…actually all </span><a href="https://groups.yahoo.com/neo/groups/kanbandev/conversations/messages/16678" target="_blank"><span style="font-size: large;">kanbandev</span></a><span style="font-size: large;"> subscribers saw it back then…here it is - "I think the issue you are having, and this is incredible common, is that you are struggling to think and work probabilistically and continue to think deterministically. This is why paradigms are also called "mindsets." Quite literally your brain is wired to think and calculate deterministically. Changing is painful. It literally requires a rewiring of your brain."…you see…quite friendly indeed…but the best part is at the end…where he gave me some encouragement saying - "Struggle through the pain and embrace a new way of thinking. It will be worth it."<br />
<br />Indeed it was worth it.</span></span></span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-46518151966645090882013-06-29T18:41:00.001+03:002013-07-05T14:51:11.068+03:00Ликвидността на Персонала обяснена чрез Теорията на Ограниченията<span style="font-family: Arial, Helvetica, sans-serif;">Въпреки, че много от хората практикуващи Канбан се притесняват за това как да управляват вариацията на единиците работа обработвани от системата, много по-голям източник на вариация се крие в хората, вършещи работата.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Тук идва понятието Ликвидност на Персонала - където работата се възлага не най-добрите, а на средноквалифицираните хора, които едва могат да свършат работата.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Най-опитните и способни хора са оставени да плуват свободно като не се обвързват със конкретни задачи. Така че, ако има проблем, те са незабавно на разположение за да помогнат на средноквалифицираните хора да се справят с него. В същото време, тъй като те не са ангажирани с конкретна единица работа, това че помагат на някого няма да доведе до забавяне на нещо друго.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">От гледна точка на Теорията на Ограниченията прилагайки Ликвидността на Персонала ние изграждаме капацитетен буфер за покриване на специалните вариации в процеса на работа.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Това на практика означава, че ние следваме Петте фокусиращи стъпки, препоръчвани от Теорията на Ограниченията:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">1) Ние идентифицирахме ограничението на системата - средноквалифицираните хора, които едва могат да свършат работата. Те обаче са достатъчно квалифицирани за да поемат естествената вариация в единиците работа.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">2) Ние решихме как да как да максимизираме използването на ограничението - като средноквалифицираните хора работят със всички сили работа, която едва могат да свършат.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">3) Ние подчинихме всичко останало на ограничението - най-способните хора не са тези, които вършат работата.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">4) Ние увеличаваме капацитета на ограничението на система - чрез обучение на средноквалифицираните хора. В същото време ние обучаваме и най-способните хора, за да се гарантира, че системното ограничение (в случая средноквалифицираните хора) няма да се премести другаде.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">5) Връщаме се на стъпка 1, и не позволяваме инерцията да създаде ново ограничение на системата.</span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-4470998409055799862013-06-29T18:19:00.001+03:002013-06-29T18:47:05.566+03:00Staff Liquidity explained using TOC model<span style="font-family: Arial, Helvetica, sans-serif;">While many Kanban practitioners worry about how to manage the variability in the work items, the greater source of variability is to be found in the people doing the work.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Here comes the Staff Liquidity concept where we assign the work not to the best people but to the average people that could barely do it.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">The most versatile and capable people are left to float around and should not be allocated to any other tasks. So if a problem comes up, they are immediately available to address it. At the same time since they are not committed to a work item no work item will be late.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">From TOC perspective using Staff Liquidity we build a capacity buffer ready to cover the special cause variations in the work process.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">That in fact means we follow the Five Focusing Steps advocated by TOC:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">1) We have identified the system constraint - the average people that could barely do the work. They are able to absorb the common cause variation in the work items. </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">2) We decided how to exploit the system constraint - we focus on keeping the constraint as busy as possible by giving the average people work they could barely do.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">3) We subordinate everything else to the constraint - the most capable people are not the ones doing the work.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">4) We elevate the system constraint - by training the average people that could barely do the work. At the same time we train the best people as well in order to ensure that the system constraint (in this case the average people) will not move.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">5) We return to Step 1 and don't let inertia create a new system constraint.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">Reference: <a href="http://commitment-thebook.com/" target="_blank">Commitment</a></span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-74028956349331364102013-06-22T17:10:00.002+03:002013-06-28T07:57:21.907+03:00Net Profit per Day<span style="font-family: inherit;">"To develop a systemic view, it is necessary to stop chasing local optimizations. The simplest way to do so is</span><br />
<span style="font-family: inherit;">to start focusing on flow; that in turn is most easily achieved by answering a simple question:</span><br />
<span style="font-family: inherit;"><br /></span>
<br />
<div style="text-align: left;">
<span style="font-family: inherit;"><b> How much can we make per day?</b></span></div>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">The qualification “per day” changes the perspective quite radically. To be able to answer the question, more</span><br />
<span style="font-family: inherit;">information is needed; information that can be gained only by examining the system as a whole."</span><br />
<span style="font-family: inherit;"><a href="https://leanpub.com/tame-the-flow" target="_blank">Tame the Flow</a>, p.126</span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-88177743420988285652013-06-14T15:09:00.000+03:002013-06-14T15:09:04.520+03:00НОСЕТЕ СИ НОВИТЕ ДРЕХИ, МОМЧЕТА<span style="font-family: inherit;">НОСЕТЕ СИ НОВИТЕ ДРЕХИ, МОМЧЕТА</span><br />
<span style="font-family: inherit;">падаме, както ходим,</span><br />
<span style="font-family: inherit;">умираме, както спим.</span><br />
<span style="font-family: inherit;">Въпросите на тая планета</span><br />
<span style="font-family: inherit;">я решим,</span><br />
<span style="font-family: inherit;">я не решим…</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Но не казвайте: утре ще бъдем красиви.</span><br />
<span style="font-family: inherit;">Не казвайте: утре ще бъдем щастливи.</span><br />
<span style="font-family: inherit;">Не казвайте: утре ще бъдем, ще бъдем…</span><br />
<span style="font-family: inherit;">Ще обичаме утре,</span><br />
<span style="font-family: inherit;">утре ще бъда любим.</span><br />
<span style="font-family: inherit;">Носете си новите дрехи, момчета,</span><br />
<span style="font-family: inherit;">падаме, както ходим,</span><br />
<span style="font-family: inherit;">умираме, както спим.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Не казвайте: утре ще почнем голямото,</span><br />
<span style="font-family: inherit;">днес да спечелим пари за прехраната.</span><br />
<span style="font-family: inherit;">Не казвайте: утре да бъдем честни,</span><br />
<span style="font-family: inherit;">днес тихичко</span><br />
<span style="font-family: inherit;">ще се проврем…</span><br />
<span style="font-family: inherit;">Носете си новите дрехи, момчета,</span><br />
<span style="font-family: inherit;">ходейки падаме,</span><br />
<span style="font-family: inherit;">сънувайки мрем.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Не казвайте: утре с вик на площада</span><br />
<span style="font-family: inherit;">ще кажа истината, после – на клада!</span><br />
<span style="font-family: inherit;">На клада, но утре. А днес потърпете,</span><br />
<span style="font-family: inherit;">днес се налага</span><br />
<span style="font-family: inherit;">да премълчим…</span><br />
<span style="font-family: inherit;">Носете си новите дрехи, момчета –</span><br />
<span style="font-family: inherit;">падаме, както ходим,</span><br />
<span style="font-family: inherit;">умираме, както спим!</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">—Стефан Цанев</span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-3180754005817266112013-05-23T14:34:00.001+03:002013-05-23T14:36:18.889+03:00Creed by Steve Turner<br />
<span style="font-family: inherit;">Creed</span><br />
<span style="font-family: inherit;">by Steve Turner</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe in </span>Marxfreudanddarwin<br />
<span style="font-family: inherit;">We believe everything is OK</span><br />
<span style="font-family: inherit;">as long as you don't hurt anyone</span><br />
<span style="font-family: inherit;">to the best of your definition of "hurt",</span><br />
<span style="font-family: inherit;">and to the best of your definition of "knowledge".</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe in sex before, during, and</span><br />
<span style="font-family: inherit;">after marriage.</span><br />
<span style="font-family: inherit;">We believe in the therapy of sin.</span><br />
<span style="font-family: inherit;">We believe that adultery is fun.</span><br />
<span style="font-family: inherit;">We believe that sodomy’s OK.</span><br />
<span style="font-family: inherit;">We believe that taboos are taboo.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that everything's getting better</span><br />
<span style="font-family: inherit;">despite evidence to the contrary.</span><br />
<span style="font-family: inherit;">The evidence must be investigated</span><br />
<span style="font-family: inherit;">And you can prove anything with evidence.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe there's something in horoscopes,</span><br />
<span style="font-family: inherit;">UFO's and bent spoons.</span><br />
<span style="font-family: inherit;">Jesus was a good man just like Buddha,</span><br />
<span style="font-family: inherit;">Mohammed, and ourselves.</span><br />
<span style="font-family: inherit;">He was a good moral teacher though we think</span><br />
<span style="font-family: inherit;">His good morals were very bad.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that all religions are basically the same-</span><br />
<span style="font-family: inherit;">at least the one that we read was.</span><br />
<span style="font-family: inherit;">They all believe in love and goodness.</span><br />
<span style="font-family: inherit;">They only differ on matters of creation,</span><br />
<span style="font-family: inherit;">sin, heaven, hell, God, and salvation.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that after death comes the Nothing</span><br />
<span style="font-family: inherit;">Because when you ask the dead what happens</span><br />
<span style="font-family: inherit;">they say nothing.</span><br />
<span style="font-family: inherit;">If death is not the end, if the dead have lied, then its</span><br />
<span style="font-family: inherit;">compulsory heaven for all excepting perhaps</span><br />
<span style="font-family: inherit;">Hitler, Stalin, and Genghis Kahn</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe in Masters and Johnson</span><br />
<span style="font-family: inherit;">What's selected is average.</span><br />
<span style="font-family: inherit;">What's average is normal.</span><br />
<span style="font-family: inherit;">What's normal is good.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe in total disarmament.</span><br />
<span style="font-family: inherit;">We believe there are direct links between warfare and</span><br />
<span style="font-family: inherit;">bloodshed.</span><br />
<span style="font-family: inherit;">Americans should beat their guns into tractors .</span><br />
<span style="font-family: inherit;">And the Russians would be sure to follow.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that man is essentially good.</span><br />
<span style="font-family: inherit;">It's only his behavior that lets him down.</span><br />
<span style="font-family: inherit;">This is the fault of society.</span><br />
<span style="font-family: inherit;">Society is the fault of conditions.</span><br />
<span style="font-family: inherit;">Conditions are the fault of society.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that each man must find the truth that</span><br />
<span style="font-family: inherit;">is right for him.</span><br />
<span style="font-family: inherit;">Reality will adapt accordingly.</span><br />
<span style="font-family: inherit;">The universe will readjust.</span><br />
<span style="font-family: inherit;">History will alter.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe that there is no absolute truth</span><br />
<span style="font-family: inherit;">excepting the truth that there is no absolute truth.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">We believe in the rejection of creeds,</span><br />
<span style="font-family: inherit;">And the flowering of individual thought.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">If chance be the Father of all flesh,</span><br />
<span style="font-family: inherit;">disaster is his rainbow in the sky</span><br />
<span style="font-family: inherit;">and when you hear:</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">"State of Emergency!"</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">"Sniper Kills Ten!"</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">"Troops on Rampage!"</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">"Whites go Looting!"</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">"Bomb Blasts School!"</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">It is but the sound of man</span><br />
<span style="font-family: inherit;">worshipping his maker.</span>Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-54770284195355788212013-05-23T12:02:00.001+03:002013-05-23T12:02:25.691+03:00Everyone has to play a part in leadership<br />
<div style="background-color: white; border: 0px; color: #4c4c4c; margin-bottom: 24px; padding: 0px;">
<span style="font-family: inherit;">"Everyone has to play a part in leadership.</span></div>
<div style="background-color: white; border: 0px; color: #4c4c4c; margin-bottom: 24px; padding: 0px;">
<span style="font-family: inherit;">"You get different types of leadership - some are purely by action and inspiration, others by organisation and more verbal."</span></div>
<div style="background-color: white; border: 0px; color: #4c4c4c; margin-bottom: 24px; padding: 0px;">
<span style="font-family: inherit;">Brendan Rodgers</span></div>
Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-45605353833501464072013-04-27T18:14:00.003+03:002013-04-27T18:14:57.683+03:00Risk Profile for a project<br />
<span style="font-family: Arial, Helvetica, sans-serif;">First let's define what is a risk is - according to ISO 31000, risk is the “effect of uncertainty on objectives” affecting the completion of a project. Uncertainty (or lack of certainty) is a state of being that involves a deficiency of information and leads to inadequate or incomplete knowledge or understanding. In the context of risk management, uncertainty exists whenever your knowledge or understanding of an event, consequence, or likelihood is inadequate or incomplete. </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">We use a Risk profile for each work item that enters our Kanban system. In order to prepare the Risk Profile for the product we will have to analyse it first. If we know the work that needs to be done (B part of the matrix) we can start analysing for the C part of the matrix.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">The uncertainty about nature of the demand or the amount and type of work is the source of the Business risk. There are three major cases:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">1.<span class="Apple-tab-span" style="white-space: pre;"> </span>The client knows exactly what needs to be done e.g. develop an algorithm for calculating Pythagoras' theorem. (B1)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">2.<span class="Apple-tab-span" style="white-space: pre;"> </span>The client knows what needs to be done but not exactly e.g. develop my site to be like Oxford University site but better! (B2)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">3.<span class="Apple-tab-span" style="white-space: pre;"> </span>The client has just a vague idea of what needs to be done e.g. develop an indoor positioning system using RFID tokens (B3)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">The uncertainty about if our capability would match the demand is the source of the Capability risk. Again three major cases:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">1.<span class="Apple-tab-span" style="white-space: pre;"> </span>We have all the skills and knowledge required to do the job (C1)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">2.<span class="Apple-tab-span" style="white-space: pre;"> </span>We have almost all of skills and knowledge required to do the job (C2)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">3.<span class="Apple-tab-span" style="white-space: pre;"> </span>We have none of the skills and knowledge required to do the job (C3)</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">The C/B matrix represents the Risk Profile for the project we'll need to execute in order to deliver the product.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">The worst case for us is the combination B3C3. We should never work on it if that is the case. We can safely make a delivery date commitment for B1C1, not that safely for B1C2. The most challenging but at the same time the most rewarding case is B3C2. One may say how come since we have almost all of the skills & knowledge (C2) but not all (C1)? First of all if the product is something new and never done before we could not be able to know beforehand the exact skills set needed. And second - it is more rewarding both for us and for the client if the product is something unique something never done before.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">We are assigning a Risk profile to the project and not to the product. The reason behind is that one and the same product implemented by a different team will definitely end up with different lead time and budget. The project represents the unique combination of Product and Development team.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">In order to simplify the quantification we will group the work items based on their Risk profiles.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Here is the new grouping:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>Low Risk Profile - all B1C1, B2C1 work items</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>Medium Risk Profile - all B1C2, B2C2 work items</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>High Risk Profile - all B1C3, B2C3, B3C2, B3C3 work items</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Risk profile quantification:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>Shows variability in cycle time per work item</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">•<span class="Apple-tab-span" style="white-space: pre;"> </span>The numbers are unique per project</span><br />
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Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-57491620464898898022013-04-20T13:34:00.000+03:002013-04-23T14:47:43.965+03:00Планиране на проект с помощта на Закона на Литъл<h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Въведение</span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Законът на Литъл работи със средни стойности. Той ни помага да изчислим средното време което една заявка прекарва във системата. Когато изпълняваме проект ние разбиваме на части продукта, който трябва да се достави като резултат от проекта. Ние се интересуваме колко време ще отнеме на системата за да изработи всички части. Точно това е което прави Формулата на Андерсън – тя ни дава зависимостта между средното оперативно време за дадена част и времето за което целият проект ще може да се достави.<br />
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Закон на Литъл</span></span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Нека си припомним, че за производствени системи Законът на Литъл се записва по малко по-различен начин, а именно:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyuwveL3kG7I-3ORsPqzKMOI2m2C4zjzvat6pDezWhOf95zZuFasGBSpMuVaj9lkW1BknI6hC57rwXZj92jcw8Y-N9RX4PbPL976jEGHvOU1hTPjVHdlVY7BNbxTFOaD6sQwLEqw/s1600/Littles+Law.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyuwveL3kG7I-3ORsPqzKMOI2m2C4zjzvat6pDezWhOf95zZuFasGBSpMuVaj9lkW1BknI6hC57rwXZj92jcw8Y-N9RX4PbPL976jEGHvOU1hTPjVHdlVY7BNbxTFOaD6sQwLEqw/s1600/Littles+Law.png" style="border: none; box-shadow: none;" /></a></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">където WIP (количество незавършена продукция) e складовата наличност между началната и крайната точка на производственият процес; TH (дебит) e средният брой произведени продукти; CT (оперативно време) е средното време между постъпването на една заявка в производството до складирането и като готов продукт или с други думи времето което заявката прекарва като WIP. Този закон е валиден за всяка една система още повече, че може да се приложи и за подсистеми или система в системата. Например в банка, опашката пред касиерите може да е една система, а всеки един от касиерите друга система и Законът на Литъл може да се приложи за всяка една от тях както и към всички заедно. Нарочно използвам TH, WIP и CT за по-лесна ориентация при четене на документи на английски.<br />
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Формула на Андерсън</span></span></span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Нека разгледаме следният случай от практиката - планиране на проект. На Фиг.1 имаме две нива на производствената система и съответно две гледни точки (перспективи):</span><br />
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<ul><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;">
<li><span style="font-family: Arial, Helvetica, sans-serif;">• Ниво Проект - проект или работа значима за клиента</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">• Ниво Разработка - компонент или работа значима за екипа. Един пример са сторитата използвани при разработката на софтуер</span></li>
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<span style="font-family: Arial, Helvetica, sans-serif;">Проекта ще се достави за времето T. Ние разбиваме доставката на N броя неща за правене или единици работа. Всички те влизат едновременно във Опашка Разработка. Размера на отделните единици работа е без значение. Когато разбиваме проекта ние не вземаме предвид от колко стъпки се се състои процеса на сървъра S2. Важно е да се отбележи, че имаме две опашки - Проект и Разработка. Опашката Проект е с размер N и Опашката Разработка е с размер [0,N]. Сървър S1 може да има оперативно време по-голямо от 0 ако това което прави е да определи коя ще е следващата работа изтеглена от опашката Проект в опашката Разработка.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH9mWA5mO1PvAQssoRMgTMxlFSYxL4UyC7_jf_dFXtNARheNmbbcjr2y1b9g9QqnUjg45KT5Jxw7gKssHCHm8us42i7Fq8Zipv5klDyJxRcdFa7Jp3HtbQKlpwDzqeY-ANXmlNjw/s1600/Project+System.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"></span></a></span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFMdQm8wAnjUGHFMWdgu1Ka2uguX5wo86ksKmD78CkrOkQ2sgyKFV1gjOB7zPtq2Lwh3B2ZMOBGpTmeVjdQ08Iaim5GI8DeuV6gZRB7XAclTHtTy7H3SAbrFuW0bTa3cSEWpQKFA/s1600/Project+System+BG.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFMdQm8wAnjUGHFMWdgu1Ka2uguX5wo86ksKmD78CkrOkQ2sgyKFV1gjOB7zPtq2Lwh3B2ZMOBGpTmeVjdQ08Iaim5GI8DeuV6gZRB7XAclTHtTy7H3SAbrFuW0bTa3cSEWpQKFA/s640/Project+System+BG.png" style="border-color: #FFF; border: none; box-shadow: none;" width="640" /></a></div>
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<span lang="BG" style="line-height: 115%;"><span style="font-family: Arial, Helvetica, sans-serif;">Фиг.1</span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></span></span></span></span></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Ние можем да получим времето на доставка използвайки формулата:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSAlKDJCyDO6I61DJybaSeCT2WSqYX0h9YGe-9wN6oLsqjRXkHvs7HOA_jcANsI89KLnANKP5MSSzYlujqAWRms9qNmgJ_t5ktcMtWwYkHluOxwQ5Ps1t_wlihJTGE2xuGyNgsWQ/s1600/Andersons+Formula+1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSAlKDJCyDO6I61DJybaSeCT2WSqYX0h9YGe-9wN6oLsqjRXkHvs7HOA_jcANsI89KLnANKP5MSSzYlujqAWRms9qNmgJ_t5ktcMtWwYkHluOxwQ5Ps1t_wlihJTGE2xuGyNgsWQ/s1600/Andersons+Formula+1.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">или ако искаме да разберем колко човека ни трябват за да доставим за определено време:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnGlNuLNDydCgNFT4vCYF9XI0N1f98p_PDHrkn2mHDCwuzLarO0sS9VnT-K99L3C3XzwKSIcJJhBRcwBmc-Km2cnhg1RXsoFH6WQS58VIIZ0LD1uYQ80ktKvq3gSTzPAWP7SbXvA/s1600/Andersons+Formula+2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnGlNuLNDydCgNFT4vCYF9XI0N1f98p_PDHrkn2mHDCwuzLarO0sS9VnT-K99L3C3XzwKSIcJJhBRcwBmc-Km2cnhg1RXsoFH6WQS58VIIZ0LD1uYQ80ktKvq3gSTzPAWP7SbXvA/s1600/Andersons+Formula+2.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"> Където:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"> <span style="font-size: large;">T</span> - времето за което проекта ще бъде завършен </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"> <span style="font-size: large;">N</span> - броят единици работа, които трябва да се свършат в интервала [0,T]</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaFEIagGGKV173afj7hmaXx500oXN6KsEU5k-H6RAkWLal1RKPL9fpjcar4Gv9gEIfUr1nleEpRZapwW34MD5geGhrkKcwuH6aRFB1xxNWEo9GrdPNyXkWe9QQqTOlx-wJ8b18pA/s1600/LTpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaFEIagGGKV173afj7hmaXx500oXN6KsEU5k-H6RAkWLal1RKPL9fpjcar4Gv9gEIfUr1nleEpRZapwW34MD5geGhrkKcwuH6aRFB1xxNWEo9GrdPNyXkWe9QQqTOlx-wJ8b18pA/s1600/LTpAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средното оперативното време на ниво проект или както го вижда клиента</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAAsQu0yy3_aD8ei54qHDNPKFLKATL2LcQ8adwY9SWa2BpBvBG6Bqvdmtbj70bMfvBCY3JFA5dPoumDEJiVbnD83XJVNImVz7Sr7cl8568xuTzycGCnSqtLwYiFt5SsOdlRY7VTA/s1600/WIPpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAAsQu0yy3_aD8ei54qHDNPKFLKATL2LcQ8adwY9SWa2BpBvBG6Bqvdmtbj70bMfvBCY3JFA5dPoumDEJiVbnD83XJVNImVz7Sr7cl8568xuTzycGCnSqtLwYiFt5SsOdlRY7VTA/s1600/WIPpAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средното количеството незавършена работа на ниво проект</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmGE-Id0VuZPczsrsaM7VX2nfw0utgQvV_4Dzs6KJPLtLJrUdw65SLUWMDZKYeX5y8xDx5Fwncx5jCjqccvxHVTJQFYMwo073CLe6gFWKbO3XVa6r-Bkfd37as6Jtge1S3G1Ei8A/s1600/WIPtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmGE-Id0VuZPczsrsaM7VX2nfw0utgQvV_4Dzs6KJPLtLJrUdw65SLUWMDZKYeX5y8xDx5Fwncx5jCjqccvxHVTJQFYMwo073CLe6gFWKbO3XVa6r-Bkfd37as6Jtge1S3G1Ei8A/s1600/WIPtAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средното количеството незавършена работа на ниво екип</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinUiguBqphkMS1ZIqzbfILVDyuKNk_pLcYecE3GgKTv5-C0JIVLmnJTEUPHj5Rk8BOojuG4lAdpFCNdt9oFCxw8EXqtN39UZfA1efYZHCqnMNxQ7t5a3dZqKE4tHbcG8QVS9jDNA/s1600/CTtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinUiguBqphkMS1ZIqzbfILVDyuKNk_pLcYecE3GgKTv5-C0JIVLmnJTEUPHj5Rk8BOojuG4lAdpFCNdt9oFCxw8EXqtN39UZfA1efYZHCqnMNxQ7t5a3dZqKE4tHbcG8QVS9jDNA/s1600/CTtAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средното оперативното време на ниво екип</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8LK1HrndGlvBzzvZ4qIHXXqvTufIPrHPRN-J6tkjQY4hDK3KXcK2YFXIrZZ8f8_c-8L2tE6YbT2722bBxwrZBIJE3z979JHSO9BPgc7leuZHVikjC9ToUMCqCCf6i37EgFLOm1A/s1600/THpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8LK1HrndGlvBzzvZ4qIHXXqvTufIPrHPRN-J6tkjQY4hDK3KXcK2YFXIrZZ8f8_c-8L2tE6YbT2722bBxwrZBIJE3z979JHSO9BPgc7leuZHVikjC9ToUMCqCCf6i37EgFLOm1A/s1600/THpAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средният дебит на ниво проект</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCmdNPLRMMIz2IjyZ-QvaVXXXu8E9eEf62r2gm50Ly7DZK2QY61xK8_ENE-eODRdpkWBliD7Er96GtudBxSnADkRZ69FgD1nJzbnJnVw44g5InSaa2qqVfv0XBVSzplHXUvfyqA/s1600/THtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCmdNPLRMMIz2IjyZ-QvaVXXXu8E9eEf62r2gm50Ly7DZK2QY61xK8_ENE-eODRdpkWBliD7Er96GtudBxSnADkRZ69FgD1nJzbnJnVw44g5InSaa2qqVfv0XBVSzplHXUvfyqA/s1600/THtAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> – средният дебит на ниво екип</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal;">Разбира се </span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal; text-align: justify;">TH</span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: x-small; font-weight: normal; text-align: justify;">t </span><span style="font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal;">е средната стойност на случайна величина с даден вид разпределение. Ако изходящият поток може да се моделира като Поасонов процес с интензитет </span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal; text-align: justify;">TH</span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: x-small; font-weight: normal; text-align: justify;">t </span><span style="font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal;">тогава нужното време за N-тата единица работа да излезе от системата се моделира с Гама разпределение </span><span class="mi" id="MathJax-Span-207" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Main; font-size: 16px; font-weight: normal; margin: 0px; padding: 0px 0px 0px 4.5px; position: static; vertical-align: 0px; white-space: nowrap;">Γ</span><span class="mo" id="MathJax-Span-208" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Main; font-size: 16px; font-weight: normal; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap;">(</span><span class="mi" id="MathJax-Span-209" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Math; font-size: 16px; font-style: italic; font-weight: normal; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap;">α</span><span class="mo" id="MathJax-Span-210" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Main; font-size: 16px; font-weight: normal; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap;">,</span><span class="mi" id="MathJax-Span-211" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Math; font-size: 16px; font-style: italic; font-weight: normal; margin: 0px; padding: 0px 0px 0px 2.7px; position: static; vertical-align: 0px; white-space: nowrap;">β<span style="border: 0px; display: inline-block; height: 1px; margin: 0px; overflow: hidden; padding: 0px; position: static; vertical-align: 0px; width: 0.1px;"></span></span><span class="mo" id="MathJax-Span-212" style="background-color: white; border: 0px; color: #555555; display: inline; font-family: MathJax_Main; font-size: 16px; font-weight: normal; margin: 0px; padding: 0px; position: static; vertical-align: 0px; white-space: nowrap;">)</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: small; font-weight: normal;"> със </span><span style="background-color: white; font-size: small; font-weight: normal; text-align: justify;"><span style="font-size: small;"><span style="font-family: Symbol; font-style: italic;">a=</span><span style="font-family: Arial, Helvetica, sans-serif;">N и </span></span></span><span style="background-color: white; font-size: small; font-weight: normal; text-align: justify;"><i style="font-family: Symbol;">b=</i><span style="font-family: Arial, Helvetica, sans-serif;">1/TH<span style="font-size: x-small;">t.</span></span></span><br />
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<span style="background-color: white; font-size: small; font-weight: normal; text-align: justify;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;"><br /></span></span></span></div>
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Доказателство на Формулата на Андерсън</span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Прилагаме Законът на Литъл за клиентското ниво:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_y9GZlif0LusRbnMA1GtFdR04390B-4XDPVUsOA5Py_eSMDOVoWU0OcMK_BsQSqFgIkP6E0uyVUo-S6_CPNN8OoTAjHgTJMSziG8FfThPhP2LrEkdsgbfjNgidUyR7PYJchhQrA/s1600/LittlesOnClientLevel.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_y9GZlif0LusRbnMA1GtFdR04390B-4XDPVUsOA5Py_eSMDOVoWU0OcMK_BsQSqFgIkP6E0uyVUo-S6_CPNN8OoTAjHgTJMSziG8FfThPhP2LrEkdsgbfjNgidUyR7PYJchhQrA/s1600/LittlesOnClientLevel.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Прилагаме Законът на Литъл и за производственото ниво:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHDSI6SdmEvaIKtUaYDL__Kdw5rmxY7PHDt9vLwYfmU2MLej0FLVgxvLmfb3RaG5dp5UwOYKfD92Lwmri0go-m2VJXKVMrc5jQdPtezYEvzq2GJ-clJ6EH8V9tW6S3dIg6g_YR_Q/s1600/LittlesOnDevLevel.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHDSI6SdmEvaIKtUaYDL__Kdw5rmxY7PHDt9vLwYfmU2MLej0FLVgxvLmfb3RaG5dp5UwOYKfD92Lwmri0go-m2VJXKVMrc5jQdPtezYEvzq2GJ-clJ6EH8V9tW6S3dIg6g_YR_Q/s1600/LittlesOnDevLevel.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">На Фиг. 1 двете системи – клиентската и производствената са свързани като изхода на производствената се влива в изхода на клиентската. Следователно дебита на клиентската система е равен на дебита на производствената или </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMAnH-n2FgQD2WFGtsX9-C2__C1MsX8rQryll_K2M0yCHWkxLvT65-HPSyJXDdwDpAJhMuWVzC9ZBwup2Ur0ksmXeSi2TFnWuS5ovTiMKvaAGBHgVlTiv6PYj5_s5oioibvno3JQ/s1600/THpAve_THtAve.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMAnH-n2FgQD2WFGtsX9-C2__C1MsX8rQryll_K2M0yCHWkxLvT65-HPSyJXDdwDpAJhMuWVzC9ZBwup2Ur0ksmXeSi2TFnWuS5ovTiMKvaAGBHgVlTiv6PYj5_s5oioibvno3JQ/s1600/THpAve_THtAve.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></span></div>
<span style="float: right; font-family: Arial, Helvetica, sans-serif;">. И в двата случая при пресмятания с помощта на Законът на Литъл трябва да използваме една и съща мерна единица за времето - минути, часове, дни и т.н. Не може да се пресмята когато дебита да е измерен в часове, а пък оперативното време да е в дни. Също така трябва да имаме една мерна единица за работата.</span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">By noting that</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2ZgsbXiLeJcOdVkkWD-G2hZ13dzGefNVZjZvVMg-ii7wN6Y4AyRGZA2uwgcqIQqytCEtviRYfk3l095T_a7gxAg-ajmvFjCwpPVIakfcp4O4WeBA0HQ5idSKfAJpubYSHCsHjew/s1600/AndersonProof1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2ZgsbXiLeJcOdVkkWD-G2hZ13dzGefNVZjZvVMg-ii7wN6Y4AyRGZA2uwgcqIQqytCEtviRYfk3l095T_a7gxAg-ajmvFjCwpPVIakfcp4O4WeBA0HQ5idSKfAJpubYSHCsHjew/s1600/AndersonProof1.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Следва:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMIcDrhyfjScSKl3XjLcSY_JNO6uf8DSKw57wvuz6nges4FwBozE153aY8cIafP33UpcghThwS10bKRCmP20VaoY5MHaeKkHyDL5fTW6qeFyNjQS1Kfbo_xszko_JOO-5uCYrOJA/s1600/AndersonProof2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMIcDrhyfjScSKl3XjLcSY_JNO6uf8DSKw57wvuz6nges4FwBozE153aY8cIafP33UpcghThwS10bKRCmP20VaoY5MHaeKkHyDL5fTW6qeFyNjQS1Kfbo_xszko_JOO-5uCYrOJA/s1600/AndersonProof2.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Също както и:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQnBtohPCmKNaFdD9FDO18W8lHr4m8B630pqNo0BLtUZGekHwr7U3Xpn2ETzoCxiFVOx5dRPQRpHFQzrgNlXQbZMAGgH3im_G-bHb92MDdAq9GQePiV1SAZbLtK76AxSdi9bpaw/s1600/AndersonProof3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQnBtohPCmKNaFdD9FDO18W8lHr4m8B630pqNo0BLtUZGekHwr7U3Xpn2ETzoCxiFVOx5dRPQRpHFQzrgNlXQbZMAGgH3im_G-bHb92MDdAq9GQePiV1SAZbLtK76AxSdi9bpaw/s1600/AndersonProof3.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">or</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgucmhiNoESjbE98hFpZJoiEa73qE2mV6d6XnYgwpxibh9tJbOJSbCNsakbzWfC_5Ck0FOPQdmr-XtO8Lw5Saf73btUV1yn8XXUrrWBh9qNQYMhT-jYYJU9Fyooa5Ww1_xGCubsBQ/s1600/AndersonProof4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgucmhiNoESjbE98hFpZJoiEa73qE2mV6d6XnYgwpxibh9tJbOJSbCNsakbzWfC_5Ck0FOPQdmr-XtO8Lw5Saf73btUV1yn8XXUrrWBh9qNQYMhT-jYYJU9Fyooa5Ww1_xGCubsBQ/s1600/AndersonProof4.png" style="border-color: #FFF; border: none; box-shadow: none;" /></span></a></div>
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Примери</span></h3>
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Оригиналният пример на Дейвид Андерсън</span></h4>
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<span style="font-family: Arial, Helvetica, sans-serif;">Имаме да доставим голям проект от 2200 единици работа. Клиента иска доставката на целият проект след 10 месеца.Трябва да отговорим на въпросите: Колко ще ни струва доставката на проекта? От колко човека ще се нуждаем?</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Тоест имаме N = 2200 единици работа, T=10 месеца = 40 седмици. Ние имаме исторически данни за организацията разработчик които показват, че средното оперативно време за единица работа е 0,4 седмици. Използвайки Формулата на Андерсън (2) имаме:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBDWMXmOOjeBQJDjMuyn8MZG4IdGcyHcQxoHk0d8KrTfYNzH8p-G6bH1vC6GlHXYuZYm9oxlIoHlPaZwivIWNUjekhaUUfYLh8dQCl7o2Wr_8cCrEEzM8ko4SmDnyOkrbMFj42_Q/s1600/Example1+BG.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBDWMXmOOjeBQJDjMuyn8MZG4IdGcyHcQxoHk0d8KrTfYNzH8p-G6bH1vC6GlHXYuZYm9oxlIoHlPaZwivIWNUjekhaUUfYLh8dQCl7o2Wr_8cCrEEzM8ko4SmDnyOkrbMFj42_Q/s1600/Example1+BG.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Организацията разработчик следва правилото за само една единица работа на човек в даден момент следователно ще ни трябват 22 души. Тук приемаме, че опашката Разработка има дължина 0 единици работа. Ако тя има дължина от 2 единици работа то ние ще се нуждаем от 20 човека.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">Този резултат трябва да се използва за средната част на Z-кривата, но това е друга тема.</span><br />
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Пример за определяне на датата на доставка</span></h4>
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<span style="font-family: Arial, Helvetica, sans-serif;">Нека имаме да доставим голям проект от 2200 единици работа. Клиента иска да знае кога ще можем да го доставим. Нямаме опции за добавяне на допълнителен персонал към организацията, която в момента е 22 човека и следователно средното количеството незавършена работа ще ни е 22 единици. Ние имаме исторически данни за организацията разработчик които показват, че средното оперативно време за единица работа е 0,4 седмици. Използвайки Формулата на Андерсън (1) имаме:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjp-VkS08lRIyt9-HJ452s7mnEeoJ7XkbM3V1zJBhRTbbG-RbGqMm27mjE0lV4iUZaN444df8zu92gn8sRMWpeT2mqagqqb6ZGXJx3YKCQuOqXdhgj4GcDpKMBV8uUxQjOBHCfvA/s1600/Example2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"></span></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7biaMnFwLh9_j7q3BGdnsVyy4Gp8A34IuswaUccZ5xbxyowY7jNLQfb9sV2KZgXsiOMSjmDVLWLmVsW2CPR2cfQz7FysLkAoWNbkT5Tqck6QuaY9Sl6ZE3DyzuJtDglnuc-YhrA/s1600/Example2+BG.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7biaMnFwLh9_j7q3BGdnsVyy4Gp8A34IuswaUccZ5xbxyowY7jNLQfb9sV2KZgXsiOMSjmDVLWLmVsW2CPR2cfQz7FysLkAoWNbkT5Tqck6QuaY9Sl6ZE3DyzuJtDglnuc-YhrA/s1600/Example2+BG.png" style="border-color: #FFF; border: none; box-shadow: none;" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Този резултат трябва да се използва за средната част на Z-кривата, но това е друга тема.</span><br />
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<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">Източници:</span></h4>
<span style="font-family: Arial, Helvetica, sans-serif;"></span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">Little, J. D. C., S. C. Graves. 2008. Little’s Law. D. Chhajed, T. J. Lowe,</span></span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">eds. Building Intuition: Insights from Basic Operations Management </span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Models and Principles. Springer Science + Business Media LLC,</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">New York.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;"><br /></span></span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;"></span></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">J. D. C. Little. Little's law as viewed on its 50th anniversary. Oper. Res. </span></span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">59 (2011) 536{539.</span><br />
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Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-77945757618550784762013-04-11T16:54:00.000+03:002013-10-27T16:19:09.701+02:00Project planning using Little’s law<h3>
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<h3>
<span style="font-family: Arial, Helvetica, sans-serif;">Introduction</span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Little's Law deals with averages. It can help us calculate the average waiting time of an item in the system. In project development we break the project delivery into work items. We are interested in how much time it will take for all the items to be processed by the system. And that is what Anderson's formula does - it gives us the relationship between the average lead time for an item and the finite </span><span style="font-family: Arial, Helvetica, sans-serif;">time period over which the project will be delivered.</span><br />
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<h3>
<span style="font-family: Arial, Helvetica, sans-serif;">
Little’s Law</span></h3>
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<span style="font-family: Arial, Helvetica, sans-serif;">Let’s recall what the Little’s Law for production systems is:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyuwveL3kG7I-3ORsPqzKMOI2m2C4zjzvat6pDezWhOf95zZuFasGBSpMuVaj9lkW1BknI6hC57rwXZj92jcw8Y-N9RX4PbPL976jEGHvOU1hTPjVHdlVY7BNbxTFOaD6sQwLEqw/s1600/Littles+Law.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyuwveL3kG7I-3ORsPqzKMOI2m2C4zjzvat6pDezWhOf95zZuFasGBSpMuVaj9lkW1BknI6hC57rwXZj92jcw8Y-N9RX4PbPL976jEGHvOU1hTPjVHdlVY7BNbxTFOaD6sQwLEqw/s1600/Littles+Law.png" style="border: currentColor; box-shadow: none;" /></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Where throughput (TH) is the average output of a production process (machine, workstation, line, plant) per unit time, work in process (WIP) is the inventory between the start and end points of a product routing, and cycle time (CT) is the average time from release of a job at the beginning of the routing until it reaches an inventory point at the end of the routing (that is, the time the job spends as WIP). </span><span style="font-family: Arial, Helvetica, sans-serif;">Handily this result applies to any system, and particularly, it applies to systems within systems. So in a bank, the queue might be one subsystem, and each of the tellers another subsystem, and Little's result could be applied to each one, as well as the whole thing.</span><br />
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<h3>
<span style="font-family: Arial, Helvetica, sans-serif;">
Anderson’s Formula</span></h3>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">Let’s consider project planning. On Fig.1 we have two levels of the system and hence two perspectives on it:</span><br />
<ul>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Client layer – project or set of customer defined requirements meaningful to the customer.</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Service level – components or work items suitable for the development organization. User stories are just an example of a suitable work item type</span></li>
</ul>
<span style="font-family: Arial, Helvetica, sans-serif;">The project will be delivered in the time T. We break down the project into N work items. All the items enter Project Queue. The size of the individual work items doesn't matter. When breaking a project down we do not consider how many steps the workflow of server S2 consists of. Important thing is that we have two queues - Project and Dev. Project queue has the size of N and Dev queue could be of any size in [0,N]. Server S1 could have service time of more than 0 if for instance what it does is to decide which would be the next item to leave Project queue and enter Dev queue.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH9mWA5mO1PvAQssoRMgTMxlFSYxL4UyC7_jf_dFXtNARheNmbbcjr2y1b9g9QqnUjg45KT5Jxw7gKssHCHm8us42i7Fq8Zipv5klDyJxRcdFa7Jp3HtbQKlpwDzqeY-ANXmlNjw/s1600/Project+System.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img height="323" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH9mWA5mO1PvAQssoRMgTMxlFSYxL4UyC7_jf_dFXtNARheNmbbcjr2y1b9g9QqnUjg45KT5Jxw7gKssHCHm8us42i7Fq8Zipv5klDyJxRcdFa7Jp3HtbQKlpwDzqeY-ANXmlNjw/s640/Project+System.png" style="border: currentColor; box-shadow: none;" width="640" /></span></a></div>
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<div style="text-align: center;">
<span style="font-family: Arial, Helvetica, sans-serif;">Fig. 1</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">We can calculate the lead time for the project using the formula:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSAlKDJCyDO6I61DJybaSeCT2WSqYX0h9YGe-9wN6oLsqjRXkHvs7HOA_jcANsI89KLnANKP5MSSzYlujqAWRms9qNmgJ_t5ktcMtWwYkHluOxwQ5Ps1t_wlihJTGE2xuGyNgsWQ/s1600/Andersons+Formula+1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSAlKDJCyDO6I61DJybaSeCT2WSqYX0h9YGe-9wN6oLsqjRXkHvs7HOA_jcANsI89KLnANKP5MSSzYlujqAWRms9qNmgJ_t5ktcMtWwYkHluOxwQ5Ps1t_wlihJTGE2xuGyNgsWQ/s1600/Andersons+Formula+1.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">We can calculate the developers we will need to deliver for a particular lead time using the formula:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnGlNuLNDydCgNFT4vCYF9XI0N1f98p_PDHrkn2mHDCwuzLarO0sS9VnT-K99L3C3XzwKSIcJJhBRcwBmc-Km2cnhg1RXsoFH6WQS58VIIZ0LD1uYQ80ktKvq3gSTzPAWP7SbXvA/s1600/Andersons+Formula+2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnGlNuLNDydCgNFT4vCYF9XI0N1f98p_PDHrkn2mHDCwuzLarO0sS9VnT-K99L3C3XzwKSIcJJhBRcwBmc-Km2cnhg1RXsoFH6WQS58VIIZ0LD1uYQ80ktKvq3gSTzPAWP7SbXvA/s1600/Andersons+Formula+2.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"> Where:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"> <span style="font-size: large;">T</span> = time period over which the project will be delivered (lead time)</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"> <span style="font-size: large;">N</span> = the number of items to be delivered or the total arrivals in [0,T]</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaFEIagGGKV173afj7hmaXx500oXN6KsEU5k-H6RAkWLal1RKPL9fpjcar4Gv9gEIfUr1nleEpRZapwW34MD5geGhrkKcwuH6aRFB1xxNWEo9GrdPNyXkWe9QQqTOlx-wJ8b18pA/s1600/LTpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaFEIagGGKV173afj7hmaXx500oXN6KsEU5k-H6RAkWLal1RKPL9fpjcar4Gv9gEIfUr1nleEpRZapwW34MD5geGhrkKcwuH6aRFB1xxNWEo9GrdPNyXkWe9QQqTOlx-wJ8b18pA/s1600/LTpAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average lead time at the project level or what the client can see</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAAsQu0yy3_aD8ei54qHDNPKFLKATL2LcQ8adwY9SWa2BpBvBG6Bqvdmtbj70bMfvBCY3JFA5dPoumDEJiVbnD83XJVNImVz7Sr7cl8568xuTzycGCnSqtLwYiFt5SsOdlRY7VTA/s1600/WIPpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAAsQu0yy3_aD8ei54qHDNPKFLKATL2LcQ8adwY9SWa2BpBvBG6Bqvdmtbj70bMfvBCY3JFA5dPoumDEJiVbnD83XJVNImVz7Sr7cl8568xuTzycGCnSqtLwYiFt5SsOdlRY7VTA/s1600/WIPpAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average work in process at the project level</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmGE-Id0VuZPczsrsaM7VX2nfw0utgQvV_4Dzs6KJPLtLJrUdw65SLUWMDZKYeX5y8xDx5Fwncx5jCjqccvxHVTJQFYMwo073CLe6gFWKbO3XVa6r-Bkfd37as6Jtge1S3G1Ei8A/s1600/WIPtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmGE-Id0VuZPczsrsaM7VX2nfw0utgQvV_4Dzs6KJPLtLJrUdw65SLUWMDZKYeX5y8xDx5Fwncx5jCjqccvxHVTJQFYMwo073CLe6gFWKbO3XVa6r-Bkfd37as6Jtge1S3G1Ei8A/s1600/WIPtAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average work in process at the development organization level</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinUiguBqphkMS1ZIqzbfILVDyuKNk_pLcYecE3GgKTv5-C0JIVLmnJTEUPHj5Rk8BOojuG4lAdpFCNdt9oFCxw8EXqtN39UZfA1efYZHCqnMNxQ7t5a3dZqKE4tHbcG8QVS9jDNA/s1600/CTtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinUiguBqphkMS1ZIqzbfILVDyuKNk_pLcYecE3GgKTv5-C0JIVLmnJTEUPHj5Rk8BOojuG4lAdpFCNdt9oFCxw8EXqtN39UZfA1efYZHCqnMNxQ7t5a3dZqKE4tHbcG8QVS9jDNA/s1600/CTtAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average lead time (cycle time) at the development organization level</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8LK1HrndGlvBzzvZ4qIHXXqvTufIPrHPRN-J6tkjQY4hDK3KXcK2YFXIrZZ8f8_c-8L2tE6YbT2722bBxwrZBIJE3z979JHSO9BPgc7leuZHVikjC9ToUMCqCCf6i37EgFLOm1A/s1600/THpAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8LK1HrndGlvBzzvZ4qIHXXqvTufIPrHPRN-J6tkjQY4hDK3KXcK2YFXIrZZ8f8_c-8L2tE6YbT2722bBxwrZBIJE3z979JHSO9BPgc7leuZHVikjC9ToUMCqCCf6i37EgFLOm1A/s1600/THpAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average throughput at the project level</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCmdNPLRMMIz2IjyZ-QvaVXXXu8E9eEf62r2gm50Ly7DZK2QY61xK8_ENE-eODRdpkWBliD7Er96GtudBxSnADkRZ69FgD1nJzbnJnVw44g5InSaa2qqVfv0XBVSzplHXUvfyqA/s1600/THtAve.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBCmdNPLRMMIz2IjyZ-QvaVXXXu8E9eEf62r2gm50Ly7DZK2QY61xK8_ENE-eODRdpkWBliD7Er96GtudBxSnADkRZ69FgD1nJzbnJnVw44g5InSaa2qqVfv0XBVSzplHXUvfyqA/s1600/THtAve.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"> = average throughput at the development organization level</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
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<span style="font-family: Arial, Helvetica, sans-serif;">Of course </span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; text-align: justify;">TH</span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: x-small; text-align: justify;">t </span><span style="font-family: Arial, Helvetica, sans-serif;">is the average of a random variable modeled by a distribution of some type. If the departure is a Poisson process with intensity </span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; text-align: justify;">TH</span><span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: x-small; text-align: justify;">t </span><span style="font-family: Arial, Helvetica, sans-serif;">then the required time for N-th work item to exit the system (be delivered) is modeled by a Gamma distribution </span><span style="background-color: white; font-family: Verdana, sans-serif; text-align: justify;">Gamma(</span><i style="background-color: white; font-family: Verdana, sans-serif; text-align: justify;"><span style="font-family: Symbol;"><span style="font-size: small;"><i>a</i></span></span></i><span style="background-color: white; font-family: Verdana, sans-serif; text-align: justify;">,</span><i style="background-color: white; font-family: Verdana, sans-serif; text-align: justify;"><span style="font-family: Symbol;"><span style="font-size: small;"><i>b</i></span></span></i><span lang="EN-GB" style="background-color: white; font-family: Verdana, sans-serif; text-align: justify;" xml:lang="EN-GB">)</span><span style="font-family: Arial, Helvetica, sans-serif;"> with </span><span style="background-color: white; text-align: justify;"><span style="font-size: small;"><span style="font-family: Symbol; font-style: italic;">a=</span><span style="font-family: Arial, Helvetica, sans-serif;">N and </span></span></span><span style="background-color: white; text-align: justify;"><i style="font-family: Symbol;">b=</i><span style="font-family: Arial, Helvetica, sans-serif;">1/TH<span style="font-size: x-small;">t.</span></span></span><br />
<i style="background-color: white; font-family: Symbol; text-align: justify;"></i><br />
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<h3>
<span style="font-family: Arial, Helvetica, sans-serif;">
Proof of Anderson’s Formula</span></h3>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">We apply Little’s Law at the client level:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_y9GZlif0LusRbnMA1GtFdR04390B-4XDPVUsOA5Py_eSMDOVoWU0OcMK_BsQSqFgIkP6E0uyVUo-S6_CPNN8OoTAjHgTJMSziG8FfThPhP2LrEkdsgbfjNgidUyR7PYJchhQrA/s1600/LittlesOnClientLevel.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_y9GZlif0LusRbnMA1GtFdR04390B-4XDPVUsOA5Py_eSMDOVoWU0OcMK_BsQSqFgIkP6E0uyVUo-S6_CPNN8OoTAjHgTJMSziG8FfThPhP2LrEkdsgbfjNgidUyR7PYJchhQrA/s1600/LittlesOnClientLevel.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Then we apply Little’s Law at the development organization level:</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHDSI6SdmEvaIKtUaYDL__Kdw5rmxY7PHDt9vLwYfmU2MLej0FLVgxvLmfb3RaG5dp5UwOYKfD92Lwmri0go-m2VJXKVMrc5jQdPtezYEvzq2GJ-clJ6EH8V9tW6S3dIg6g_YR_Q/s1600/LittlesOnDevLevel.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHDSI6SdmEvaIKtUaYDL__Kdw5rmxY7PHDt9vLwYfmU2MLej0FLVgxvLmfb3RaG5dp5UwOYKfD92Lwmri0go-m2VJXKVMrc5jQdPtezYEvzq2GJ-clJ6EH8V9tW6S3dIg6g_YR_Q/s1600/LittlesOnDevLevel.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Consider Fig.1 where the project is presented as a queuing system consisting of two queuing systems in tandem. Client and development systems are connected in a way that they share the same output. Output from the development system is flowing into the output of the client system. Hence average throughput of the client system is equal to the average throughput of the development system or </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMAnH-n2FgQD2WFGtsX9-C2__C1MsX8rQryll_K2M0yCHWkxLvT65-HPSyJXDdwDpAJhMuWVzC9ZBwup2Ur0ksmXeSi2TFnWuS5ovTiMKvaAGBHgVlTiv6PYj5_s5oioibvno3JQ/s1600/THpAve_THtAve.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMAnH-n2FgQD2WFGtsX9-C2__C1MsX8rQryll_K2M0yCHWkxLvT65-HPSyJXDdwDpAJhMuWVzC9ZBwup2Ur0ksmXeSi2TFnWuS5ovTiMKvaAGBHgVlTiv6PYj5_s5oioibvno3JQ/s1600/THpAve_THtAve.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<span style="float: right; font-family: Arial, Helvetica, sans-serif;">For both systems we have to work with the same time interval for the throughput time and throughput rate i.e. minutes, hours, days, weeks, etc. Also we have to have the same work item type – it is not possible average throughput at the project level to be measured in sites, and average throughput at the development organization level to be measured in web pages.</span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><span style="float: right; font-family: Arial, Helvetica, sans-serif;"><br /></span><br />
<div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">By noting that</span><br />
<div class="separator" style="clear: both; text-align: center;">
<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2ZgsbXiLeJcOdVkkWD-G2hZ13dzGefNVZjZvVMg-ii7wN6Y4AyRGZA2uwgcqIQqytCEtviRYfk3l095T_a7gxAg-ajmvFjCwpPVIakfcp4O4WeBA0HQ5idSKfAJpubYSHCsHjew/s1600/AndersonProof1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2ZgsbXiLeJcOdVkkWD-G2hZ13dzGefNVZjZvVMg-ii7wN6Y4AyRGZA2uwgcqIQqytCEtviRYfk3l095T_a7gxAg-ajmvFjCwpPVIakfcp4O4WeBA0HQ5idSKfAJpubYSHCsHjew/s1600/AndersonProof1.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">It follows that</span><br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMIcDrhyfjScSKl3XjLcSY_JNO6uf8DSKw57wvuz6nges4FwBozE153aY8cIafP33UpcghThwS10bKRCmP20VaoY5MHaeKkHyDL5fTW6qeFyNjQS1Kfbo_xszko_JOO-5uCYrOJA/s1600/AndersonProof2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMIcDrhyfjScSKl3XjLcSY_JNO6uf8DSKw57wvuz6nges4FwBozE153aY8cIafP33UpcghThwS10bKRCmP20VaoY5MHaeKkHyDL5fTW6qeFyNjQS1Kfbo_xszko_JOO-5uCYrOJA/s1600/AndersonProof2.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">As well as that</span><br />
<div class="separator" style="clear: both; text-align: center;">
<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQnBtohPCmKNaFdD9FDO18W8lHr4m8B630pqNo0BLtUZGekHwr7U3Xpn2ETzoCxiFVOx5dRPQRpHFQzrgNlXQbZMAGgH3im_G-bHb92MDdAq9GQePiV1SAZbLtK76AxSdi9bpaw/s1600/AndersonProof3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSQnBtohPCmKNaFdD9FDO18W8lHr4m8B630pqNo0BLtUZGekHwr7U3Xpn2ETzoCxiFVOx5dRPQRpHFQzrgNlXQbZMAGgH3im_G-bHb92MDdAq9GQePiV1SAZbLtK76AxSdi9bpaw/s1600/AndersonProof3.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<div style="text-align: center;">
<span style="font-family: Arial, Helvetica, sans-serif;">or</span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgucmhiNoESjbE98hFpZJoiEa73qE2mV6d6XnYgwpxibh9tJbOJSbCNsakbzWfC_5Ck0FOPQdmr-XtO8Lw5Saf73btUV1yn8XXUrrWBh9qNQYMhT-jYYJU9Fyooa5Ww1_xGCubsBQ/s1600/AndersonProof4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgucmhiNoESjbE98hFpZJoiEa73qE2mV6d6XnYgwpxibh9tJbOJSbCNsakbzWfC_5Ck0FOPQdmr-XtO8Lw5Saf73btUV1yn8XXUrrWBh9qNQYMhT-jYYJU9Fyooa5Ww1_xGCubsBQ/s1600/AndersonProof4.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<br />
<h3>
<span style="font-family: Arial, Helvetica, sans-serif;">
Examples</span></h3>
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></h4>
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">
Original example from David Anderson</span></h4>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">We have a major project with 2200 user stories to be delivered. The business needs the project delivered in 10 months. The questions to answer are: How much money do we need? How many people do we need?</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">So we have N = 2200 user stories, T=10 months = 40 weeks. We also have historical data that average lead time for the development organization is 0,4 weeks. Using the Anderson’s formula (2) we have:</span><br />
<div class="separator" style="clear: both; text-align: center;">
<span style="font-family: Arial, Helvetica, sans-serif; margin-left: 1em; margin-right: 1em;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMeJvjo6OgxNAzha_aa4zLeLPLVA-OtXu81rxHGBnr-nDUvw_Gb0L5RW30QZKBWZ8_7XOyLyxfeIBw4OyASBrQMYsMRAoR8hKVsfe814gB7c6q0Ux7vw5F_0crq3qF6elPTOXQ4w/s1600/Example1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMeJvjo6OgxNAzha_aa4zLeLPLVA-OtXu81rxHGBnr-nDUvw_Gb0L5RW30QZKBWZ8_7XOyLyxfeIBw4OyASBrQMYsMRAoR8hKVsfe814gB7c6q0Ux7vw5F_0crq3qF6elPTOXQ4w/s1600/Example1.png" style="border: currentColor; box-shadow: none;" /></a></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">Development organization has the policy of 1 work item per person hence we will require 22 persons. That assumes the dev queue has finite size of 0 work items. If the dev queue has finite size of 2 user stories we will need 20 persons.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;">The result should be used for the second leg of the Z-curve, but that is another topic.</span><br />
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></h4>
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">
Calculating delivery date</span></h4>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">Let’s have a similar project with major project with 2200 user stories to be delivered. The business wants to know when we will be able to deliver. There are no options for adding more developers to the development organization so we know the average work in process which is 22 user stories. We also have historical data that average lead time for the development organization is 0.4 weeks per user story. Using the Anderson’s formula (1) we have:</span><br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjp-VkS08lRIyt9-HJ452s7mnEeoJ7XkbM3V1zJBhRTbbG-RbGqMm27mjE0lV4iUZaN444df8zu92gn8sRMWpeT2mqagqqb6ZGXJx3YKCQuOqXdhgj4GcDpKMBV8uUxQjOBHCfvA/s1600/Example2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: Arial, Helvetica, sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjp-VkS08lRIyt9-HJ452s7mnEeoJ7XkbM3V1zJBhRTbbG-RbGqMm27mjE0lV4iUZaN444df8zu92gn8sRMWpeT2mqagqqb6ZGXJx3YKCQuOqXdhgj4GcDpKMBV8uUxQjOBHCfvA/s1600/Example2.png" style="border: currentColor; box-shadow: none;" /></span></a></div>
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">The result should be used for the second leg of the Z-curve, but that is another topic.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<br />
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">References:</span></h4>
<span style="font-family: Arial, Helvetica, sans-serif;"></span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">Little, J. D. C., S. C. Graves. 2008. Little’s Law. D. Chhajed, T. J. Lowe,</span></span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">eds. Building Intuition: Insights from Basic Operations Management </span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Models and Principles. Springer Science + Business Media LLC,</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">New York.</span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;"><br /></span></span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;"></span></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">J. D. C. Little. Little's law as viewed on its 50th anniversary. Oper. Res. </span></span><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">59 (2011) 536{539.</span></div>
Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com1tag:blogger.com,1999:blog-7651780.post-13902384357839366112013-03-28T10:07:00.001+02:002013-03-28T10:07:18.028+02:00Какво е проект?Вчера вечерта изнесох лекция на тема "Въведение в Канбан" в betahaus. Нарочно наблегнах на системното мислене и как Канбан ни позволява да стабилизираме всяка една система ползваща интелектуален труд. Един от присъстващите попита дали мога да опиша система, която работи само по проекти?<br />
Моят отговор беше, че независимо дали една организация работи по проекти или не ние пак трябва да я разглеждаме на първо място като система.<br />
Днес ми хрумна един пример, който мисля ще илюстрира тезата ми - пътуване с кола от точка А до точка Б.<br />
Аз всеки ден пътувам с кола от къщи до офиса. Отнеме ми средно около 10 мин и го смятам за рутинно упражнение. Факта, че го смятам за рутинно показва, че вариацията е много малка и точно затова аз мога да предвидя времето за пътуване (оперативното време) с голяма сигурност.<br />
Ако обаче реша да отида до Габрово това ще е съвсем друга история. Първо - никога не съм ходил до Габрово и съответно не зная кой път да хвана. Второ - не познавам условията по пътя - брой дупки, брой тирове и други подобни. Трето - трябва да осигуря финансиране за да мога да си платя горивото необходимо за пътуването. Видно е, че вариацията е много голяма и ако трябва да предвидя времето необходимо за пътуването аз ще трябва да поработя върху план.<br />
<br />
Пътуването до Габрово е проект. Пътуването до офиса е рутина. Но и двете пътувания ще бъдат изпълненеи от системата състояща се от мен като шофьор, колата и пътната мрежа.Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-37298309010403132472013-03-04T08:46:00.000+02:002013-03-04T08:52:05.195+02:00Goethe’s Other Coptic Song – Ein Andres<br />
<br />
<h4>
Ein Andres (Kophtisches Lied II)</h4>
<br />
<br />
Geh! Gehorche meinen Winken,<br />
<br />
Nutze deine jungen Tage,<br />
<br />
Lerne zeitig klüger sein!<br />
<br />
Auf des Glückes großer Waage<br />
<br />
Steht die Zunge selten ein.<br />
<br />
Du mußt steigen oder sinken,<br />
<br />
Du mußt herrschen und gewinnen<br />
<br />
Oder dienen und verlieren,<br />
<br />
Leiden oder triumphieren,<br />
<br />
Amboß oder Hammer sein.<br />
<br />
<br />
<br />
<br />
<h4>
Йохан Волфганг Гьоте , "Кофтска песен "<br />Превод от немски: Димитър Стоевски</h4>
<br />
<br />
<br />
Чуй и следвай моите думи<br />
<br />
не пилей напразно дните,<br />
<br />
постарай се да си умен —<br />
<br />
рядко случва се везните<br />
<br />
на съдбата да са спрели.<br />
<br />
Ще се дигаш или падаш,<br />
<br />
ще владееш и печелиш,<br />
<br />
ще робуваш и ще губиш,<br />
<br />
ще ликуваш или страдаш<br />
<br />
длъжен си да бъдеш тук<br />
<br />
наковалня или чук!<br />
<br />
<br />
<br />
<br />
<br />
<h4>
Translated by James Clarence Magnan</h4>
<br />
<br />
Go ! — but heed and understand<br />
<br />
This my last and best command :<br />
<br />
Turn thine Youth to such advantage<br />
<br />
As that no reverse shall daunt Age.<br />
<br />
Learn the serpent’s wisdom early ;<br />
<br />
And contemn what Time destroys ;<br />
<br />
Also, wouldst thou creep or climb,<br />
<br />
Chuse thy role, and chuse in time,<br />
<br />
Since the scales of Fortune rarely<br />
<br />
Shew a liberal equipoise.<br />
<br />
Thou must either soar or stoop,<br />
<br />
Fall or triumph, stand or droop ;<br />
<br />
Thou must either serve or govern,<br />
<br />
Must be slave, or must be sovereign ;<br />
<br />
Must, in fine, be block or wedge,<br />
<br />
Must be anvil or be sledge.<br />
<br />
<br />
<br />
<h4>
Translated by Edgar Alfred Bowring</h4>
<br />
<br />
Go! obedient to my call,<br />
<br />
Turn to profit thy young days,<br />
<br />
Wiser make betimes thy breast<br />
<br />
In Fate’s balance as it sways,<br />
<br />
Seldom is the cock at rest;<br />
<br />
Thou must either mount, or fall,<br />
<br />
Thou must either rule and win,<br />
<br />
Or submissively give in,<br />
<br />
Triumph, or else yield to clamour:<br />
<br />
Be the anvil or the hammer.<br />
<br />
<h4>
Translated by William Grasett Thomas</h4>
<br />
<br />
Go ! thy master’s beck obey,<br />
Profit of thy early days,<br />
“Wisdom learn without delay :<br />
On the scales of Fortune stays<br />
Seldom e’er the tongue at rest ;<br />
Rise thou must, or be depressed,<br />
Rule and gain must be for thee,<br />
Or must learn to serve and lose,<br />
Triumph must or suffering choose,<br />
Hammer must or anvil be.<br />
<br />
<br />
<br />
<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-41523891824451368472013-02-28T19:47:00.000+02:002013-02-28T19:47:24.946+02:00Д-р Деминг извършва "Експеримента с Червените топчета"<div class="separator" style="clear: both; text-align: center;">
<span style="text-align: left;"><br /></span></div>
<div class="separator" style="clear: both; text-align: justify;">
<span style="text-align: left;">Много интересно видео показващо как д-р Деминг извършва "Експеримента с Червените топчета".</span></div>
<div class="separator" style="clear: both; text-align: justify;">
<span style="text-align: left;"><br /></span></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<object width="320" height="266" class="BLOGGER-youtube-video" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,40,0" data-thumbnail-src="http://1.gvt0.com/vi/L_2EFTQy_v0/0.jpg"><param name="movie" value="http://www.youtube.com/v/L_2EFTQy_v0&fs=1&source=uds" /><param name="bgcolor" value="#FFFFFF" /><param name="allowFullScreen" value="true" /><embed width="320" height="266" src="http://www.youtube.com/v/L_2EFTQy_v0&fs=1&source=uds" type="application/x-shockwave-flash" allowfullscreen="true"></embed></object></div>
<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-3455775379000392032013-02-27T19:08:00.000+02:002013-04-12T11:04:14.014+03:00How can we move variability out of the system?<br />
How can we move variability out of the system? By outsourcing it.<br />
<br />
"...Needless to say, the loss of industrial jobs is a disaster for industrial workers, and for politicians whose efforts depend on large pools of organized labor (more on that later). But unless one is an industrial<br />
worker, a trade union, or a left-wing democratic politician this is great news. Why? Because it means that the underlying economy loses most of its cyclicality. Let us explain:<br />
• The industrial part of the production process is by far the most cyclical of the three step (design, produce, sell) process described in the first chapter.<br />
• So as companies outsource the ‘production’ part, they effectively outsource the volatile part of the business process to someone else.<br />
• This means that, when underlying economic activity is weaker then had been forecast, Western companies do not end up with the excess inventories, excess labor etc. It is the suppliers that have<br />
to deal with any excesses left over by the unforeseen economic soft spot.<br />
<br />
To illustrate this, imagine the following situation. Due to an unexpected event (9/11? Tech bust? Very cold weather?) furniture sales in North America are all of a sudden much weaker than had been anticipated<br />
initially by IKEA. So what does IKEA do? It picks up the phone and calls its supplier in Indonesia (or Poland, Mexico etc.) and says:<br />
Ikea: “Sorry. I know that, this time last year, we ordered 50,000 cupboards from you. But this month, we will only need 5,000.”<br />
Supplier: “But I have already bought the wood for 50,000 cupboards?”<br />
Ikea: “Really? Then I guess you can give me a special deal on the 5,000 cupboards that I do need. After all, you will want to get rid of your wood inventory.”<br />
Supplier: “But how am I supposed to make my employee payrolls?”<br />
Ikea: “Sorry my friend. There are two kinds of problem in the capitalist world in which we live: mine, and not mine. Your inventory and payroll issues are the second kind of problem.”<br />
<br />
Because of the slowdown in the demand for furniture, the supplier in Mexico (or elsewhere) is then forced to lay off people. Meanwhile, the designers at IKEA are hard at work on finding new designs that will draw<br />
people back into the stores, as are the IKEA marketing teams. In neither of the latter two activities do we witness many lay-offs. IKEA’s people in Sweden and the United States remain duly employed and the shock is absorbed by the Mexican economy."<br />
<br />
From one very interesting quite old but still very relevant book <a href="http://gavekal.com/eBooks/OurBraveNewWorld.pdf">Our Brave New World</a><br />
<br />
Written by Anatole Kaletsky, Charles Gave, Louis-Vincent Gave<br />
Edition: <a href="http://gavekal.com/page6.cfm">GaveKal Research</a><br />
<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-2463832476467280572013-02-21T16:56:00.001+02:002013-02-21T16:56:56.832+02:00Resilient ArchitectureResilient Architecture principle: Early detection - Fast recovery.<br />
<br />
Hindsight doesn't lead to foresight!Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-10316183779960620082013-02-21T13:59:00.000+02:002013-02-24T17:48:15.738+02:00Законът на Литъл е всъщност само частен случай...<span style="font-family: inherit;">Законът на Литъл </span><span style="background-color: white; color: #222222; font-family: Arial, Helvetica, sans-serif; font-size: medium; line-height: 14.467592239379883px;">L = λW</span><span style="font-family: inherit;"> всъщност е частен случай на по-общата теорема (Закон на Брумел) </span><span style="background-color: white; color: #222222; font-family: Arial, Helvetica, sans-serif; font-size: medium; line-height: 14.467592239379883px;">H = λG</span><span style="background-color: white; color: #222222; font-family: inherit; font-size: medium; line-height: 14.467592239379883px;"> </span><span style="background-color: white; color: #222222; font-family: inherit; line-height: 14.467592239379883px;">където </span><span style="color: #222222; font-family: inherit;"><span style="line-height: 14.458333015441895px;">за всеки елемент влизащ в системата се дефинира тегловна функция </span></span><span style="font-family: inherit;">f</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">(t). Подробно описание има в използваната литература.</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="background-color: white; color: #222222; font-size: medium; line-height: 14.458333015441895px;"><span style="font-family: Arial, Helvetica, sans-serif;">H = λG</span><span style="font-family: inherit;"> </span></span><span style="font-family: inherit;">ни позволява да сложим различни тегловни функции</span>, например разход или печалба<span style="font-family: inherit;"> на времето, което всеки елемент i прекарва в системата. Законът на Литъл е частен случай където f</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">(t)=1 за t ∈ [t</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">,t</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">+l</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">] и l</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">=W</span><span style="font-family: inherit; font-size: x-small;">i</span><span style="font-family: inherit;">. </span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Пример:</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;">Магазин сайт има средно 1000 клиента/ден. Всеки клиент харчи средно по 5 лв. Искаме да знаем колко е средният приход на магазина на ден. Използвайки закона на Брумел:</span><br />
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;"><span style="background-color: white; color: #222222; line-height: 14.458333015441895px;">H (<span style="font-family: inherit;">среден </span>приход на ден) </span></span><span style="background-color: white; color: #222222; font-family: inherit; line-height: 14.458333015441895px;">= λ (среден брой клиенти на ден) G (среден харч от клиент)=1000 клиента/ден * 5 лв = 5000лв/ден</span><br />
<span style="background-color: white; color: #222222; font-family: Arial, Tahoma, Helvetica, FreeSans, sans-serif; line-height: 14.458333015441895px;"><br /></span><span style="background-color: white; color: #222222; line-height: 14.458333015441895px;"><br /></span>
<br />
<div style="background-color: white; color: #222222; font-family: Arial, Tahoma, Helvetica, FreeSans, sans-serif; line-height: 10.416666030883789px;">
<span style="font-size: x-small;">Използвана литература:</span></div>
<div style="background-color: white; color: #222222; font-family: Arial, Tahoma, Helvetica, FreeSans, sans-serif; font-size: 13.310184478759766px; line-height: 10.416666030883789px;">
<br /></div>
<div style="background-color: white; color: #222222; font-family: Arial, Tahoma, Helvetica, FreeSans, sans-serif; font-size: 13.310184478759766px; line-height: 10.416666030883789px;">
<span style="font-size: xx-small;"><a href="http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf" style="color: #888888; text-decoration: initial;">http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf</a></span></div>
Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-10172075357450830092013-02-13T15:11:00.000+02:002013-02-14T14:52:13.431+02:00Кога е приложим Законът на Литъл?Нека си припомним, че Законът на Литъл гласи, че "усредненият брой на елементите в системата (L) е равен на усредненото темпо, с което тези елементи постъпват (λ) в системата, умножена по усредненото време което даден елемент прекарва (W) в системата".<br />
<br />
<span style="font-size: large;"> L = λW (1)</span><br />
<span style="font-size: large;"><br /></span>
Законът на Литъл е валиден в случаите когато имаме:<br />
<br />
<ul>
<li>стабилна система - стационарен стохастичен процес на постъпване на елементите в системата и и стационарен процес на обслужване на елементите. </li>
<li>нестабилна система - нестационарен стохастичен процес на постъпване на елементите в системата и и стационарен процес на обслужване на елементите, но пък 1) времевият интервал в който наблюдаваме системата е ограничен 2) в началото и краят на наблюдението системата е празна; 3)всички постъпили елементи ще бъдат обслужени и ще напуснат системата т.е. няма "загубени"</li>
</ul>
<div>
<br /></div>
И в двата случая при пресмятания с помощта на Законът на Литъл трябва да използваме една и съща мерна единица за времето - минути, часове, дни и т.н. Не може да се пресмята когато дебита да е измерен в часове, а пък оперативното време да е в дни.<br />
<div>
<br /></div>
<div>
При нестабилна система ние не можем да използваме Законът на Литъл докато системата не се изпразни. Това не е недостатък - просто показва, че ние измерваме какво се е случило, а не предвиждаме какво ще се случи. Още нещо за отбелязване е, че ако интервалът на наблюдение е да кажем 1 ден то всеки един отделен ден резултата от изчислението ще е различен, но Законът на Литъл ще е валиден.</div>
<div>
<br /></div>
<div>
Какво се разбира под "усреднен"? Това не са очаквани стойности защото ние не работим с разпределяния на случайни величини. Когато говорим за темпото на постъпване и времето на обслужване се разбира усреднени стойности на извадката. Когато се говори за опашката се има предвид усредненият брой за фискиран времеви интервал. </div>
<div>
<br /></div>
<div>
<div>
За производствени системи Законът на Литъл се записва по малко по-различен начин, а именно:</div>
<div>
<br /></div>
<div>
<span style="font-size: large;">TH=WIP/CT (2)</span></div>
<div>
<br /></div>
<div>
където WIP (количество незавършена работа) e средният брой изпълнявани заявки между началната и крайната точка на прозводственият процес; TH (дебит) e средният брой изпълнение заявки; CT (оперативно време) е средното време между постъпването на една заявка в производството до завършането и или с други думи времето което заявката прекарва като WIP.</div>
</div>
<div>
<br /></div>
<div>
Такава система не е стабилна и затова за да приложим Законът на Литъл ще трябва да имаме система закоято са изпълнени условията за нестабилна система, а именно:</div>
<div>
<ul>
<li>Времевият интервал в който наблюдаваме системата е ограничен.</li>
<li>Използваме една и съща мерна единица за времето за всички параметри.</li>
<li>Ако системата се изпразва то тя трябва да е празна в краят на времевият интервал.</li>
<li>Ако системата никога не се изпразва то: </li>
<ul>
<li>количеството незавършена работа (WIP) в началото на измерването трябва да е приблизително равно на количеството в края на измерването така, че няма значително увеличаване или намаляване. Това покрива изискването системата да е изпразнена в края на времевият интервал.</li>
<li>Средната възраст на количеството незавършена работа (WIP) не трябва нито да се увеличава нито да намалява по време на измерването. </li>
</ul>
</ul>
</div>
<div>
<br /></div>
<div>
След като изложихме свойствата които дадена система трябва да има за да можем да приложим Законът на Литъл нека изложим нещо също толкова важно - системните характеристики на които не трябва да обръщаме внимание за да го прилагаме:</div>
<div>
<ul>
<li>Големината на елементите влизащи в системата</li>
<li>Разпределението на стохастичен процес на постъпване на елементите в системата и и стационарен процес на обслужване на елементите</li>
<li>Колко човека работят върху определена заявка</li>
<li>Реда на изпълнение на заявките</li>
<li>И всичко друго за което се сетим!</li>
</ul>
</div>
<div>
<br /></div>
<div>
<br /></div>
<div>
<br /></div>
<div>
<span style="font-size: x-small;">Използвана литература:</span></div>
<div>
<a href="http://web.mit.edu/sgraves/www/papers/Little's%20Law-Published.pdf"><span style="font-size: x-small;">http://web.mit.edu/sgraves/www/papers/Little's%20Law-Published.pdf</span></a></div>
<div>
<span style="font-size: x-small;"><a href="http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf">http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf</a></span><br />
<a href="http://www.informs.org/content/download/255814/2414705/file/flaw-Little-and-Wolff-29dec11.pdf"><span style="font-size: x-small;">http://www.informs.org/content/download/255814/2414705/file/flaw-Little-and-Wolff-29dec11.pdf</span></a></div>
<div>
<br /></div>
Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-28255010456334764792013-02-11T18:45:00.000+02:002013-02-11T18:53:54.554+02:00Примери за използването на Законът на ЛитълНека отново напишем Законът на Литъл:<br />
<br />
<br />
<span style="font-size: large;">TH=WIP/CT</span><br />
<br />
където WIP (количество незавършена продукция) e складовата наличност между началната и крайната точка на прозводственият процес; TH (дебит) e средният брой произведени продукти; CT (оперативно време) е средното време между постъпването на една заявка в производството до складирането и като готов продукт или с други думи времето което заявката прекарва като WIP.<br />
<br />
Нарочно използвам TH, WIP и CT за по-лесна ориентация при четене на документи на английски.<br />
<br />
Няколко примера:<br />
<br />
1) Продавач във магазин има средно 4 клиента на опашка на касата. Нов клиент пристига средно на 2 минути. Колко време средно ще чака един клиент за да бъде обслужен?<br />
<br />
TH(дебит)=0,5клиента/мин<br />
WIP (количество незавършена работа)=4 клиента<br />
CT(оперативно време)=WIP/TH=4/0,5=8 минути<br />
<br />
2) Ресторант има места за 60 човека. Един човек прекарва средно по 2 часа в ресторанта. Колко човека влизат в ресторанта средно на час?<br />
<br />
<br />
WIP (количество незавършена работа)=60 клиента<br />
CT(оперативно време)=2 часа<br />
TH(дебит)=WIP/CT=60/2=30 човека/час<br />
<br />
<br />
3) Застрахователен брокер получава средно по 160 запитвания на ден за продуктите които предлага. Обработката на една запитване отнема средно 30 минути. Ръководството иска да е сигурно, че всяко едно запитване ще бъде обработено в деня в който е получено. Приема се че всяко запитване се обработва само от един служител. Колко служителя ще са необходими за обработка на запитванията?<br />
<br />
CT(оперативно време)=0,5 запитвания/час<br />
TH(дебит)=160 запитвания/ден=20 запитвания/час<br />
WIP (количество незавършена работа)=TH*CT=20*0,5=10 заявки*1 служител=10 служителя<br />
<br />
За правилното използване на Закона на Литъл трябва да се уверим, че се използва същата мерна единица за време (час, минути, ден) за Оперативното време и за Дебита.<br />
<br />
4) Ресторант за сандвичи използва 3500кг месо на седмица. Управителя иска да е сигурен, че когато се използва месото е на не повече от 2 дена. Колко килограма месо трябва да се поддържат в хладилника?<br />
<br />
CT(оперативно време)=2 дни<br />
TH(дебит)=3500кг/седмица=500кг/ден<br />
WIP (количество незавършена работа)=TH*CT=500*2=1000кг<br />
<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-43140776289270742172013-02-09T19:38:00.002+02:002013-02-10T17:38:41.449+02:00Закон на ЛитълПреди малко повече от 50 години беше доказана теорема, която въпреки че не е със сложна природа, има силно въздействие върху множество браншове. Законът на Литъл остави своя отпечатък върху лечебни заведения, банки, магазини и производствени предприятия всяко едно от които може да се разгледа като Система за Масово Обслужване(СМО).<br />
<br />
През 1961 г. Джон Литъл (в момента M.I.T. професор) доказа, че за СМО "усредненият брой на елементите в системата (L) е равен на усредненото темпо, с което тези елементи постъпват (<span style="background-color: white; color: #222222; font-family: arial, sans-serif; font-size: x-small; line-height: 16px;">λ</span>) в системата, умножена по усредненото време което даден елемент прекарва (W) в системата".<br />
<br />
<span style="background-color: white; color: #222222; font-family: arial, sans-serif; font-size: large; line-height: 16px;"> L = λW (1)</span><br />
<span style="background-color: white; color: #222222; font-family: arial, sans-serif; font-size: x-small; line-height: 16px;"><br /></span>
<br />
Тук е оригиналната статия <a href="http://or.journal.informs.org/content/9/3/383.abstract">http://or.journal.informs.org/content/9/3/383.abstract</a><br />
<br />
Тук <a href="http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf">http://www.informs.org/content/download/255808/2414681/file/little_paper.pdf</a> е прегледа от автора по повод 50 годишнината на теоремата.<br />
<br />
След като го прочетете за първи път, законът може да предизвика известно объркване, но със реалистични примери теорията става ясна. "Системата" може да бъде всяко едно обслужващо клиенти предприятие например магазин, банка, екип за разработка на софтуер или накратко всяка една СМО. В Рексинтегра ние ползваме този закон за управление на проектите за разработка на софтуер.<br />
<br />
Пример, илюстриращ СМО е една бензиностанция с няколко колонки, които представляват обслужващи устройства. Автомобилите, които постъпват за обслужване – това са клиентите (или заявките за обслужване). Темпото на пристигане на клиентите (<span style="background-color: white; color: #222222; font-family: arial, sans-serif; font-size: x-small; line-height: 16px;">λ</span>) има случаен характер. Времето за зареждане на всеки един клиент (W) също е със случаен характер.<br />
<br />
Законът на Литъл се отнася за СМО. СМО се състои от отделни обекти които ще наричаме заявки които постъпват в системата с определено темпо. Вътре в системата заявките могат да образуват една или повече опашки, изпълняват се и накрая напускат системата.<br />
Фиг. 1 показва това схематично:<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhm4YpMnpE5HBAeM8_m5GdTYKJ4O-Y0IiZyxmbE4oVhq0Y3l2ZSDpJBe4sNy4APoWeR_e4yjls2FvhsY-CctDiC0ylCiWDfE8yjtbLdEydnzYaOD6dyhK3bb4VIk0JbPDnwLUDpg/s1600/queueing+system.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="100" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhm4YpMnpE5HBAeM8_m5GdTYKJ4O-Y0IiZyxmbE4oVhq0Y3l2ZSDpJBe4sNy4APoWeR_e4yjls2FvhsY-CctDiC0ylCiWDfE8yjtbLdEydnzYaOD6dyhK3bb4VIk0JbPDnwLUDpg/s400/queueing+system.png" width="400" /></a></div>
<br />
В повечето случаи изпълнението на заявките се явява стеснението заради което се образуват опашките от чакащи заявки, и затова обикновенно имаме време за изпълнение по-голямо от нула. Ако имаме време за изпълнение приемаме, че имаме и време за изчакване. Понякога се прави разлика между брой заявки в опашката и общ брой изчакващи в опашки и изпълнявани заявки, като второто се нарича брой заявки в системата.<br />
<br />
За производствени системи Законът на Литъл се записва по малко по-различен начин, а именно:<br />
<br />
<span style="font-family: Arial, Helvetica, sans-serif; font-size: large;">TH</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: large;">=</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: large;">WIP/</span><span style="font-family: Arial, Helvetica, sans-serif; font-size: large;">CT (2)</span><br />
<br />
където WIP (количество незавършена продукция) e складовата наличност между началната и крайната точка на прозводственият процес; TH (дебит) e средният брой произведени продукти; CT (оперативно време) е средното време между постъпването на една заявка в производството до складирането и като готов продукт или с други думи времето което заявката прекарва като WIP.<br />
<br />
Лесно се вижда, че (2) е еквивалентно на (1) като TH=<span style="background-color: white; color: #222222; font-family: arial, sans-serif; font-size: x-small; line-height: 16px;">λ, </span><span style="background-color: white; color: #222222; line-height: 16px;"><span style="font-family: inherit;">WIP=L и CT=W. Обаче има една по-голяма разлика и тя е, че законът е зададен със средното темпо на напускане вместо със средното време за постъпване в системата.</span></span><br />
<span style="background-color: white; color: #222222; line-height: 16px;"><span style="font-family: inherit;">Това отразява една производствена система където "напускането" на готовите продукти е смисълът за съществуването на системата. Както се вижда за да увеличим дебита трябва или да увеличим количеството незавършена продукция или да намалим оперативното време или и двете заедно.</span></span><br />
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Нека отделим време за да осмислим Законът на Литъл. Той има ли отражение върху начина на работа на вашата организация? Ако да - как? Ако не - защо?Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-7419742414361583302013-01-16T09:58:00.002+02:002013-01-16T09:58:28.326+02:00Българската култура: Пример 1<a href="http://www.segabg.com/article.php?id=632396">Статия</a> във в-к Сега брой 4590 (13) 16.01.2013г<br />
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<h4>
Групата трябва да се пази</h4>
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"Времето е смутно, тече възродителен процес. Няколко турчета са подчинени на Горанов. Той <b>не ги закача</b>. От градския комитет на партията му се обаждат ту да ги уволнява, ту да ги назначава. Горанов <b>ги пази</b>, обръща се към тях с родните имена....На Варненския митрополит Кирил, сложих си ръка на сърцето и му казах: <b>не съм вярващ. Но ние сме християни хора</b>. В църквите не виждам лошо. Църквата на нищо лошо не ни учи, напротив - <b>обединява</b> <b>хората</b>, да стават по-добри....Писахме писма до партии, банки, институции. Но трябва да ти призная, и заради малко връзки стана."<br />
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<h4>
Законите не важат за всички</h4>
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"Село Дръндар, <b>родното</b> на Ахмед Доган, също е в община Суворово. Кметските наместници редовно се събират в административния център, правят оперативки. Наместник в Дръндар е Зюмбюл Али, сестра на Касим Дал....Веднъж Зюмбюл и Горан се разприказват, от дума на дума той праща поздрави на стария си приятел бай Ахмед. "Знаеш ли го", пита Горан. "Е как, той ми е <b>комшия</b>", възкликва Зюмбюл. Ахмед казва <b>добри думи за Горан</b>....Преди това Зюмбюл съдейства и за ремонт на пътя между Баново и съседното село Калиманци. Отива суворовска делегация в София при Доган, него го няма. Касим Дал, в <b>отлични отношения със Сокола</b> тогава, разписва за ремонта. Скоро ужасното шосе е чисто ново....Бай Горан не страда от лицемерие: "Връзките помагат". Надълго и широко разказва как са помагали и през комунизма."<br />
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Вижда се високи PDI, UAI, нисък LTO (Hofstede);<br />
Вижда се Ascription status, Specific relationships, Defuse relationships ( Trompenaars);<br />
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<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-75069651392682122912013-01-13T10:40:00.001+02:002013-06-13T09:34:01.151+03:00IDV and how it affects outsourcing<br />
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<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">Universalism vs. Particularism (Trompenaars)</span></h4>
<span style="font-family: Arial, Helvetica, sans-serif;">Universalism is the belief in:</span><br />
<ul>
<li><span style="font-family: Arial, Helvetica, sans-serif;">rules or laws that can be applied to everyone;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">agreements and contracts are used as the basis for doing business;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">rules are used to determine what is right;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">contracts should not be altered;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">ideas and practices can be applied everywhere without modification.</span></li>
</ul>
<span style="font-family: Arial, Helvetica, sans-serif;">Particularism is the belief in:</span><br />
<ul>
<li><span style="font-family: Arial, Helvetica, sans-serif;">placing emphasis on friendships and looking at the situation to determine what is right or ethically</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">acceptable</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">deals are made based upon friendships;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">agreements are changeable;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">different people hold different views about reality;</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">circumstances dictate how ideas and practices should be applied.</span></li>
</ul>
<h4>
<span style="font-family: Arial, Helvetica, sans-serif;">Individualism vs. Collectivism (Hofstede)</span></h4>
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<span style="font-family: Arial, Helvetica, sans-serif;">Individualism</span><span style="font-family: Arial, Helvetica, sans-serif;"> </span><span style="font-family: Arial, Helvetica, sans-serif;">is the belief in:</span><span style="font-family: Arial, Helvetica, sans-serif;"> </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"></span><br />
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<ul>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Everyone is supposed to take care of him- or</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">herself and his or her immediate family only</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">"I" – consciousness </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Right of privacy </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Speaking one's mind is healthy </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Others classified as individuals </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Personal opinion expected: one person one vote </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Transgression of norms leads to guilt feelings </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Languages in which the word "I" is indispensable </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Purpose of education is learning how to learn </span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Task prevails over relationship </span></li>
</ul>
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<span style="font-family: Arial, Helvetica, sans-serif;">Collectivism is the belief in:</span><br />
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<ul>
<li style="font-family: Arial, Helvetica, sans-serif;">People are born into extended families or clans which protect them in exchange for loyalty</li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">"We" –consciousness</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Stress on belonging</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Harmony should always be maintained</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Others classified as in-group or out-group</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Opinions and votes predetermined by in-group</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Transgression of norms leads to shame feelings</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Languages in which the word "I" is avoided</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Purpose of education is learning how to do</span></li>
<li><span style="font-family: Arial, Helvetica, sans-serif;">Relationship prevails over task</span></li>
</ul>
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<div style="font-family: Arial, Helvetica, sans-serif;">
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<div style="font-family: Arial, Helvetica, sans-serif;">
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<span style="font-family: Arial, Helvetica, sans-serif;">"The distinction between in-group and out-groups that is so essential in collectivist culture pattern has far-reaching consequences for business relationships, beyond those between employers and employees. In individualist societies the norm is universalist, treating everybody alike. Preferential treatment of one customer over others is considered bad business practice and unethical. In collectivist societies the norm is particularist. As the distinction between "our group" and "other groups" is at the very root of people's consciousness, treating one's friends better than others is natural and ethical and sound business practice." p. 238, Culture's Consequences, G. Hofstede</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">"A consequence of particularist thinking it that in a collectivist society a relationship of trust should be established between two parties before they can do any business. Through this relationship, both parties adopt the other into their in-groups, and from that moment onward both are entitled to preferential treatment. This process of adoption takes time - depending on the situation, from several hours to several years. A relationship is established with a person rather than with a company. To the collectivist mind, only natural persons are worthy of trust, and via these persons their friends and colleagues, but not impersonal legal entities like companies. So in the collectivist society <b>the personal relationship prevails over the task and over the company</b> and should be established first; in the individualist society, in contrast, <b>the task and the company are supposed to prevail over any personal relationships</b>. Naive Western businesspersons who try to force quick business in collectivist culture condemn themselves to negative discrimination as out-group members." p. 239, Culture's Consequences, G. Hofstede</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></div>
<span style="font-family: Arial, Helvetica, sans-serif;">According to <a href="http://geert-hofstede.com/bulgaria.html" target="_blank">http://geert-hofstede.com/bulgaria.html</a><span style="background-color: white; color: #222222; line-height: 10.416666030883789px;"> Bulgaria </span><span style="color: #222222;"><span style="line-height: 10.40625px;">with a score of 30 is considered a collectivist society. </span></span></span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: #222222;"><span style="line-height: 10.40625px;"><br /></span></span></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: #222222;"><span style="line-height: 10.40625px;">From Asia: India scores 48, but a</span></span></span><span style="color: #222222; font-family: Arial, Helvetica, sans-serif;"><span style="line-height: 10.40625px;">t a score of 20 China is a highly collectivist culture</span></span><span style="color: #222222; font-family: Arial, Helvetica, sans-serif; line-height: 10.40625px;">!</span><br />
<span style="color: #222222; font-family: Arial, Helvetica, sans-serif; line-height: 10.40625px;"><br /></span>
<span style="color: #222222; font-family: Arial, Helvetica, sans-serif;"><span style="line-height: 10.40625px;">With a score of 46, also in this dimension Argentina sits in the middle rankings. As a consequence of the aforementioned migration waves and the early emergence of wide middle classes, Argentina is, by far, the most individualistic of all Latin countries.</span></span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: #222222;"><span style="line-height: 10.40625px;"><br /></span></span></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: #222222;"><span style="line-height: 10.40625px;">For a comparison </span></span></span><span style="color: #222222; font-family: Arial, Helvetica, sans-serif;"><span style="line-height: 10.40625px;">The United States, with a score of 91 on this dimension, is a highly individualistic culture. </span></span><br />
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<br />Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-31021825064656805092012-12-26T11:54:00.001+02:002012-12-26T11:54:42.480+02:00Dave Snowden's thought #2<br />
"If the system is chaotic/random then agent behaviour is<br />
deterministic, which means I can use statistical instruments. If it’s constrained,<br />
then the constraint structure allows predictability/repeatability. Strong<br />
constraints produce linear causality; weaker constraints provide repeatability<br />
that may be non-linear. However the moment you get the phase shift into a<br />
co-evolutionary relationship between agents and system then there is no repeatability<br />
except by accident. In that context there is no meaningful causality, and<br />
any causality is only retrospectively coherent."<br />
Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-3015216829895640162012-12-26T11:35:00.001+02:002012-12-26T11:53:05.935+02:00Dave Snowden's thought #1It is good to have Dave Snowden's thoughts on paper, because most of them I have only on video.<br />
Here is the first one:<br />
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"We manage the emergence of beneficial coherence, within attractors, within boundaries. The only things we can manage are the probes, the boundaries and amplification/dampening of emergent patterns. " from The Children's Party StoryAnonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0tag:blogger.com,1999:blog-7651780.post-57782589676209636862012-12-18T18:07:00.003+02:002012-12-18T18:07:59.263+02:00Shu-ha-riThe "kata" or form is the educational core of all traditional Japanese knowledge schools. It is the most visible representation of a school’s knowledge packaged into one seemingly simple set of movements or concepts.<br />
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"Shu-ha-ri" literally means embracing the kata, diverging from the kata and discarding the kata. The pursuit of training in a classical Japanese marshal arts training almost always follows this educational process. This unique approach to learning has existed for centuries in Japan.Anonymoushttp://www.blogger.com/profile/05992655498642711639noreply@blogger.com0