MediaWiki API result
This is the HTML representation of the JSON format. HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format. To see the non-HTML representation of the JSON format, set format=json.
See the complete documentation, or the API help for more information.
{
"compare": {
"fromid": 1,
"fromrevid": 1,
"fromns": 0,
"fromtitle": "Main Page",
"toid": 2,
"torevid": 2,
"tons": 0,
"totitle": "A Simulation Environment for Supply Chains",
"*": "<tr><td colspan=\"2\" class=\"diff-lineno\" id=\"mw-diff-left-l1\" >Line 1:</td>\n<td colspan=\"2\" class=\"diff-lineno\">Line 1:</td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div><del class=\"diffchange diffchange-inline\"><strong>MediaWiki has been installed.</strong></del></div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">__NOTOC__</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">== Introduction ==</ins></div></td></tr>\n<tr><td class='diff-marker'> </td><td class='diff-context'></td><td class='diff-marker'> </td><td class='diff-context'></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div><del class=\"diffchange diffchange-inline\">Consult </del>the <del class=\"diffchange diffchange-inline\">[https://www</del>.<del class=\"diffchange diffchange-inline\">mediawiki</del>.<del class=\"diffchange diffchange-inline\">org/wiki/Special:MyLanguage/Help:Contents User</del>'<del class=\"diffchange diffchange-inline\">s Guide] for information on using </del>the <del class=\"diffchange diffchange-inline\">wiki software</del>.</div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">=== Defining a supply chain ===</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">A supply chain is a goal-oriented network of processes and stockpoints used to deliver goods and services to customers. '''Processes''' represent </ins>the <ins class=\"diffchange diffchange-inline\">individual activities involved in producing and distributing goods and services</ins>. <ins class=\"diffchange diffchange-inline\">'''Stockpoints''' represent locations in the supply chain where inventories are held</ins>. <ins class=\"diffchange diffchange-inline\">Processes and stockpoints are connected by a ''</ins>'<ins class=\"diffchange diffchange-inline\">network''', which describes </ins>the <ins class=\"diffchange diffchange-inline\">various paths by which goods and services can flow through a supply chain. Finally, note that our definition of a supply chain specifies that it is '''goal oriented'''</ins>.</div></td></tr>\n<tr><td class='diff-marker'> </td><td class='diff-context'></td><td class='diff-marker'> </td><td class='diff-context'></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div>== <del class=\"diffchange diffchange-inline\">Getting started </del>==</div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div>=== <ins class=\"diffchange diffchange-inline\">Strategy </ins>=<ins class=\"diffchange diffchange-inline\">==</ins></div></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div>* <del class=\"diffchange diffchange-inline\">[https</del>:<del class=\"diffchange diffchange-inline\">//www</del>.<del class=\"diffchange diffchange-inline\">mediawiki</del>.<del class=\"diffchange diffchange-inline\">org/wiki/Special</del>:<del class=\"diffchange diffchange-inline\">MyLanguage/Manual</del>:<del class=\"diffchange diffchange-inline\">Configuration_settings Configuration settings list]</del></div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">From an operations perspective, a business unit is evaluated in terms of:</ins></div></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div>* <del class=\"diffchange diffchange-inline\">[https</del>://<del class=\"diffchange diffchange-inline\">www</del>.<del class=\"diffchange diffchange-inline\">mediawiki</del>.<del class=\"diffchange diffchange-inline\">org/wiki/Special</del>:<del class=\"diffchange diffchange-inline\">MyLanguage</del>/<del class=\"diffchange diffchange-inline\">Manual</del>:<del class=\"diffchange diffchange-inline\">FAQ MediaWiki FAQ]</del></div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Cost</ins></div></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div>* <del class=\"diffchange diffchange-inline\">[https</del>:/<del class=\"diffchange diffchange-inline\">/lists</del>.<del class=\"diffchange diffchange-inline\">wikimedia</del>.<del class=\"diffchange diffchange-inline\">org</del>/<del class=\"diffchange diffchange-inline\">mailman/listinfo/mediawiki</del>-<del class=\"diffchange diffchange-inline\">announce MediaWiki release mailing list]</del></div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Quality</ins></div></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div><del class=\"diffchange diffchange-inline\">* </del>[<del class=\"diffchange diffchange-inline\">https:</del>/<del class=\"diffchange diffchange-inline\">/www</del>.<del class=\"diffchange diffchange-inline\">mediawiki</del>.<del class=\"diffchange diffchange-inline\">org/wiki/Special</del>:<del class=\"diffchange diffchange-inline\">MyLanguage/Localisation</del>#<del class=\"diffchange diffchange-inline\">Translation_resources Localise MediaWiki </del>for <del class=\"diffchange diffchange-inline\">your language</del>]</div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Speed</ins></div></td></tr>\n<tr><td class='diff-marker'>\u2212</td><td class='diff-deletedline'><div><del class=\"diffchange diffchange-inline\">* </del>[<del class=\"diffchange diffchange-inline\">https</del>://<del class=\"diffchange diffchange-inline\">www</del>.<del class=\"diffchange diffchange-inline\">mediawiki</del>.<del class=\"diffchange diffchange-inline\">org</del>/<del class=\"diffchange diffchange-inline\">wiki</del>/<del class=\"diffchange diffchange-inline\">Special</del>:<del class=\"diffchange diffchange-inline\">MyLanguage/Manual</del>:<del class=\"diffchange diffchange-inline\">Combating_spam Learn how to combat spam on your wiki]</del></div></td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Service</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Flexibility</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Quality vs. Cost:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Speed vs. Cost:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Service vs. Cost:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Flexibility vs. Cost:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Having observed that different business conditions call for different operational capabilities, we can look upon supply chain design as consisting of two parts:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Ensuring operational fit with strategic objectives.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"># Achieving maximal efficiency within the constraints established by strategy.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Copying best practices, generally called benchmarking, can only partially ensure that an operations system fits its strategic goals (i.e., because the benchmarked system can only approximate the system under consideration). And benchmarking cannot provide a way to move efficiency beyond historical levels, since it is by nature imitative. Thus, effective operations and supply chain management requires something beyond benchmarking.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">=== Setting goals ===</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">By describing how a system works, a supply chain science offers the potential to:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Identify the areas of greatest leverage;</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Determine which policies are likely to be effective in a given system;</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div>* <ins class=\"diffchange diffchange-inline\">Enable practices and insights developed for one type of environment to be generalized to another environment;</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Make quantitative tradeoffs between the costs and benefits of a particular action;</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Synthesize the various perspectives of a manufacturing or service system, including those of logistics, product design, human resources, accounting, and management strategy.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">=== Structuring the study ===</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">With this as our objective, the remainder of this book is organized into three parts:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Station Science: considers the operational behavior of an individual process and the stockpoint from which it receives material. Our emphasis is on the factors that serve to delay the flow of entities (i.e., goods, services, information or money) and hence causes a buildup of inventory in the inbound stockpoint.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Line Science: considers the operational behavior of process flows consisting of logically connected processes separated by stockpoints. We focus in particular on the issues that arise due to the coupling effects between processes in a flow.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Supply Chain Science</ins>: <ins class=\"diffchange diffchange-inline\">considers operational issues that cut across supply chains consisting of multiple products, lines and levels. A topic of particular interest that arises in this context is the coordination of supply chains that are controlled by multiple parties.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">== Capacity ==</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">The fundamental activity of any operations system centers around the flow of entities through processes</ins>. <ins class=\"diffchange diffchange-inline\">The flows typically follow routings that define the sequences of pro- cesses visited by the entities</ins>. <ins class=\"diffchange diffchange-inline\">In almost all operations systems, the following performance measures are key:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Throughput</ins>: <ins class=\"diffchange diffchange-inline\">the rate at which entities are processed by the system,</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">* Work in Process (WIP)</ins>: <ins class=\"diffchange diffchange-inline\">the number of entities in the system, which can be mea- sured in physical units (e.g., parts, people, jobs) or financial units (e.g., dollar value of entities in system),</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div>* <ins class=\"diffchange diffchange-inline\">Cycle Time</ins>: <ins class=\"diffchange diffchange-inline\">the time it takes an entity to traverse the system, including any rework, restarts due to yield loss, or other disruptions.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Typically, the objective is to have throughput high but WIP and cycle time low. The extent to which a given system achieves this is a function of the system?s overall efficiency. A useful measure of this efficiency is inventory turns, defined as</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$InventoryTurns=Troughput</ins>/<ins class=\"diffchange diffchange-inline\">WIP $$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">where throughput is measured as the cost of goods sold in a year and WIP is the dollar value of the average amount of inventory held in the system. This measure of how efficiently an operation converts inventory into output is the operational analogy of the return-on-investment (ROI) measure of how efficiently an investment converts capital into revenue. As with ROI, higher turns are better.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\"><center>![alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">f-1-1</ins>.<ins class=\"diffchange diffchange-inline\">png "Figure 1</ins>.<ins class=\"diffchange diffchange-inline\">1</ins>: <ins class=\"diffchange diffchange-inline\">A System with Yield Loss.")<</ins>/<ins class=\"diffchange diffchange-inline\">center></ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">=== Measuring capacity ===</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">A major determinant of throughput, WIP, and cycle time, as well as inventory turns, is the system?s capacity. Capacity is defined as the maximum average rate at which entities can flow through the system, and is therefore a function of the capacities of each process in the system. We can think of the capacity of an individual process as</ins>:</div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$process capacity = base capacity \u2212 detractors$$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">The process that constrains the capacity of the overall system is called the *</ins>*<ins class=\"diffchange diffchange-inline\">bottleneck**. Often, this is the slowest process. We measure this through the utilization</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">level, which is the fraction of time a station is not idle, and is computed as</ins>:</div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$utilization = rateintostation </ins>/ <ins class=\"diffchange diffchange-inline\">capacityofstation$$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">### Limits on Capacity</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Principle (Capacity): The output of a system cannot equal or exceed its capacity.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">The short term fluctuations are due to variability, but the trend is unmistakably toward station overload.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Over the long run, WIP will go up. When release rate is the same as the production rate, the WIP level will stay high for a long time because there is no slack capacity to use to catch up</ins>. <ins class=\"diffchange diffchange-inline\">Theoretically, if we run for an infinite amount of time, WIP will go to infinity even though we are running exactly at capacity</ins>.</div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">![alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">f-1</ins>-<ins class=\"diffchange diffchange-inline\">2.png "Figure 1.2: WIP versus Time in a System with Insufficient Capacity.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">!</ins>[<ins class=\"diffchange diffchange-inline\">alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">f-1-3</ins>.<ins class=\"diffchange diffchange-inline\">png "Figure 1</ins>.<ins class=\"diffchange diffchange-inline\">3</ins>: <ins class=\"diffchange diffchange-inline\">Two Outcomes of WIP versus Time at with Releases at 100% Capacity.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">##</ins># <ins class=\"diffchange diffchange-inline\">Impact of Utilization</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">The behavior illustrated in the above examples underlies the second key principle of capacity:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Principle (Utilization): Cycle time increases in utilization and does so sharply as utilization approaches 100%.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">As we have seen, when utilization is low, the system can easily keep up with the arrival of work (e.g., Figure 1.4) but when utilization becomes high the system will get behind any time there is any kind of temporary slowdown in production (e.g., Figure 1.3).</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">One might think that the \u201claw of averages\u201d might make things work </ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">out. But because the machine cannot \u201csave up\u201d production when it is ready but there is no WIP, the times the machine is starved do not make up </ins>for <ins class=\"diffchange diffchange-inline\">the times it is swamped.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">![alt text</ins>]<ins class=\"diffchange diffchange-inline\">(figure/f-1-4.png "Figure 1.4: Two Outcomes from Releasing at 82% of Capacity.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">The only way the machine can be always busy is to have a large enough pile of WIP in front of it so that it never starves. If we set the WIP level to anything less than infinity there is always a sequence of variations in process times, outages, setups, etc. that will exhaust the supply of WIP. Hence, achieving higher and higher utilization levels requires more and more WIP. Since entities must wait behind longer and longer queues, the cycle times also increase disproportionately with utilization. The result is depicted in Figure 1.5, which shows that as a station is pushed closer to capacity (i.e., 100 percent utilization), cycle times increase nonlinearly and explode to infinity before actually reaching full capacity.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">!</ins>[<ins class=\"diffchange diffchange-inline\">alt text](figure/f-1-5.png "Figure 1.5</ins>: <ins class=\"diffchange diffchange-inline\">Nonlinear Relationship of Cycle Time to Utilization.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">![alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">f-1-6.png "Figure 1.6: Mechanics Underlying Overtime Vicious Cycle.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">## Variability</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$WIP = throughput \u00d7 cycle time$$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">### Measuring Variability</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Coefficient of variation (CV) which is defined as:</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$CV = standard deviation </ins>/ <ins class=\"diffchange diffchange-inline\">mean$$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Interestingly, if we have a large collection of independent customers arriving to a server (e</ins>.<ins class=\"diffchange diffchange-inline\">g</ins>.<ins class=\"diffchange diffchange-inline\">, toll booths, calls to 9-1-1) the CV will always be close to one. Such arrival processes are called Poisson and fall right between the high variability (CV > 1) and low variability (CV < 1) cases.</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">![alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">f-2-1.png "Figure 2.1: High and low variability arrivals.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">### Influence of Variability</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">$$Cycle Time = Delay + Process Time$$</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">![alt text](figure</ins>/<ins class=\"diffchange diffchange-inline\">t-2-1.png "Table 2.1</ins>: <ins class=\"diffchange diffchange-inline\">Effective Process Times from Various Processes.")</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">----</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">## Literature Review</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">## Method</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">### Definitions</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">#### Default production facility</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">1. INPUT: Inventory unitRaw material</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">2. PROCESS: Production unit</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">3. OUTPUT</ins>: <ins class=\"diffchange diffchange-inline\">Inventory unitFinished product</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">\ufffc\ufffc</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Input = 100</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">Process = Input x 0.7 (%30 is waste) Output = Process</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">AB</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div> </div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">## Analysis</ins></div></td></tr>\n<tr><td colspan=\"2\"> </td><td class='diff-marker'>+</td><td class='diff-addedline'><div><ins class=\"diffchange diffchange-inline\">## Conclusion</ins></div></td></tr>\n\n<!-- diff cache key db767642791:diff::1.12:old-1:rev-2 -->\n"
}
}