Footnotes

¹ This statement is based on this author’s experience as a cadet in the U.S. Army at West Point in the early 1970’s.

² Adapted from http://en.wikipedia.org/wiki/Analytic_Hierarchy_Process, March 5, 2011.

³ Given a square matrix A, the scalar λ and non-zero vector v are said to be the eigenvalue and the eigenvector of A if Av = λv.

⁴ This bathtub curve is the sum of four Weibull curves f(t) = αβ^−αt^α−1 exp(−(t/β)^α) with α = 0.5, 1, 3, and 10, β = 135, for t in the range (1,250).

⁵ The partial autocorrelation at lag k is the autocorrelation between x_t and x_t-k that is not accounted for by lags 1 through k – 1.

⁶ The figure above is different from the original because it puts high market share on the right rather than the left.

⁷ Email communication with the author in the fall of 2010.

⁸ This author purchased an HP 35 scientific calculator for over $300 in 1973; calculators with the same functions can be purchases today for under $25.

⁹ This website is no longer active.

¹⁰ The website www.ncbi.nlm.nih.gov/pmc/articles/PMC1116851 supports this statement.

¹¹ The website www.wested.org/online_pubs/po-01-03.pdf supports this statement

¹² These statements are based on personal experiences of the author.

¹³ The critical ratio dispatching rule can be implemented in software as: If due > now then CR = (1 + due – now)/(1 + trpt); otherwise CR = (due – now)/(1 + TRPT), where due is the due date (in hours), now is the current date (in hours), and trpt is the total remaining processing time in hours (Rose, 2002). Note that other variants of the critical ratio rule are presented in the literature and used in practice.

¹⁴ Cycle stock is also called the lotsize inventory. This is inventory in the “saw-toothed” graph that goes up when an order is received and then goes down over time as units are drawn out of inventory. The lotsize inventory does not include the safety stock, which is the inventory below the “saw-toothed” graph.

¹⁵ This example was motivated by a similar one from Professor John Grout. Professor Grout has many other interesting examples of error proofing on his website at http://facultyweb.berry.edu/jgrout/everyday.html (April 17, 2011).

¹⁶ Exponential decay is defined for continuous time while geometric decay is only defined for discrete values. Exponential decay is defined as y(t) = a exp(–βt), where t is a real number, and geometric decay is defined as y_n = an^–b, where n is an integer.

¹⁷ The weights going back in time follow a geometric progression with initial value α and a common ratio of (1 − α). The sum of the weights from lag 1 to infinity is 1.

¹⁸ The webpage www.wiwi.uni-jena.de/Entscheidung/alb provides a video and an overview of the research on this problem.

¹⁹ John Nash was awarded the Nobel Prize in Economics in 1994 and was the subject of the film A Beautiful Mind in 2001.

²⁰ For n = 170, the Excel value was y ≈ 171.0000000000540; for n = 3000, y ≈ 3001.000000006510.

²¹ http://elsmar.com/Forums/showthread.php?t=30789, June 14, 2010.

²² “Gray” with an “a” is used in America and “grey” with an “e” is used in England and everywhere else outside the U.S.

²³ Private conversation with Professor Chris Nachtscheim, Carlson School of Management, University of Minnesota.

²⁴ The names for periodic review systems are not standard in the literature.

²⁵ www.iso.org/iso/iso_catalogue/management_and_leadership_standards/quality_management/iso_9000_essentials.htm, February 24, 2011.

²⁶ This observation was made by the author from a plant tour in the early 1990s.

²⁷ These quotes are from a talk given by Scot Webster in the Carlson School of Management on October 27, 2004.

²⁸ Interestingly, John Krafcik was named President and CEO of Hyundai North America in 2008. Under his leadership, Hyundai increased its marketshare by 50% (source: http://www.hyundainews.com/Executive_Bios.asp, April 23, 2011).

²⁹ Check truncation is the process of taking an image of the check, using Optical Character Recognition (OCR) to convert the information into digital form, and storing the checks until no longer needed.

³⁰ Source: Professor Arthur V. Hill’s PowerPoint talk on Mass Customization.

³¹ The term “disassembly” was selected by this author. This term is not widely used in the literature.

³² The difference between the sample standard deviation and times the sample MAD will approach zero as the sample size goes to infinity.

³³ Raison d’être is a French phrase that means reason to be or justification for existence. This phase is often written in English as “raison d’etre” without the ê.

³⁴ This is algorithm 26.2.17 from Abramowitz and Stegun (1964), which claims a maximum absolute error < 7.5·10⁻⁸. The VBA implementation above increases the number of significant digits for the parameter and uses the “if-then” condition provided in Press but not in Abramowitz and Stegun.

³⁵ Like the other organizations in this list, LEI is a non-profit; however, it is not a professional society like the others.

³⁶ The Supply Chain Council is closely identified with the SCOR model.

³⁷ This term has multiple meanings. See the cycle time entry for more details.

³⁸ Lean could be classified as “better” (because it reduces defects), “faster” (because it reduces cycle time), and “cheaper” (because it reduces waste and cost). The same is true for several other types of metrics.

³⁹ Some experts argue that Dell is not lean because their suppliers carry much of their inventory.

⁴⁰ Friedman uses the term “insourcing” here very differently than the way most supply chain managers use the term.

⁴¹ The word “begets” is an old English word that means to bring about, create, or father.

⁴² These are reworded slightly here.

⁴³ It is not clear if this term should be plural (periods), plural possessive (periods’ supply), or singular possessive (period’s supply). The plural is used here based on the assumption that this expression is short for periods of supply.

⁴⁴ It is not clear if this term should be plural (periods), plural possessive (periods’ supply), or singular possessive (period’s supply). The plural is used here based on the assumption that this expression is short for periods of supply.

⁴⁵ This is the average time between arrivals for customers.

⁴⁶ The “unique” components are those that are needed only for the product being terminated. If a component is also needed in a product that is not being terminated, the component cannot be terminated.

⁴⁷ In some cases, it is possible to still have an assembly line for low-volume products by using mixed model assembly.

⁴⁸ It is possible to have continuous flow for low-volume products by using automation and mass customization strategies.

⁴⁹ The is from a private conversation with Cathy Clements, former Vice President, Fueling the Future, Ecolab, in 2007.

⁵⁰ In Garvin’s framework, reliability and durability are practically synonymous.

⁵¹ Both spellings “queuing” and “queueing” are found in the literature. It is not clear which one is preferred.

⁵² The entry on interval notation explains the precise meaning of the brackets (, [, ), and].

⁵³ Humorous aside: 3M has a copyright on the color canary yellow.

⁵⁴ Source: Personal conversations with Best Buy management in 2009.

⁵⁵ The point here is that organizations should consider ALL of their stakeholders.

⁵⁶ Private communication with the author many years ago.

⁵⁷ According to Wikipedia, xeriscaping refers to landscaping and gardening to reduce the need for supplemental irrigation.

⁵⁸ The Soviet Union was a secretive society, which meant that photocopies were rarely used.

⁵⁹ This list was compiled by the author over many years from many sources.

⁶⁰ It is important, in this author’s view, to separate lean thinking from the Toyota Production System. Lean thinking is a philosophy that can be applied to any organization in any industry and may go well beyond any practices used at Toyota.

⁶¹ This adapted version of Porter’s value chain positions the primary activities at the top and the support activities below.

⁶² The difference between the standard deviation and will approach zero as the sample size goes to infinity.

⁶³ Rungtusanatham, Rabinovich, Ashenbaum, and Wallin (2007) call this cell “inventory speculation.”

⁶⁴ Rungtusanatham, Rabinovich, Ashenbaum, and Wallin (2007) call this cell “forward consignment with VMI or VOIM.”

⁶⁵ See the hidden factory entry for an explanation of this term.