Content By Harish Jose

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By: Harish Jose

Recently, I came across an interesting insight at Toyota’s website. I was taken aback by the first sentence of this paragraph: “Eventually, the value added by the line’s human operators disappears.”

The complete paragraph is shown below:
“Eventually, the value added by the line’s human operators disappears, meaning any operator can use the line to produce the same result. Only then is the jidoka mechanism incorporated into actual production lines. Through the repetition of this process, machinery becomes simpler and less expensive, while maintenance becomes less time consuming and less costly, enabling the creation of simple, slim, flexible lines that are adaptable to fluctuations in production volume.”

Generally, we talk about increasing the value-added activities in lean or the Toyota Production System (TPS). Here, Toyota seems to be stating a paradox: We should get so good at what we do that we do not add value anymore. We keep finding better and better ways at doing what we do so eventually the process doesn’t necessarily need us to do that job.

Harish Jose’s picture

By: Harish Jose

Today I’m looking at the ideas inspired by mirror neurons. Mirror neurons are a class of neurons that activate when someone engages in an activity, or when they observe the same activity being performed by someone else.

The phenomenon was first identified by a group of Italian neurophysiologists led by Giacomo Rizzolatti during the 1980s. They were studying macaque monkeys. As part of their research, they placed electrodes in the monkeys’ brains to study hand and mouth motions. The story goes that the electrodes sent signals when the monkeys observed the scientists eating peanuts. The same neurons that fired when the monkeys were eating peanuts fired when they merely observed the same action.

Several additional studies indicate that the mirror neurons are activated to respond to goal-oriented actions. For example, when a scientist covered the peanut bowl but still performed the action of picking up a peanut and eating it, the mirror neurons still fired, even though the monkeys couldn’t see the peanut bowl. However, when the scientist simply mimicked the action of taking a peanut without a peanut bowl, the neurons didn’t fire. There have been several hypotheses regarding the mirror neurons, such as they facilitate learning by copying, and that they are the source for empathy.

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By: Harish Jose

Today I’m looking at the “house” of the Toyota Production System (TPS). The illustration below shows the two pillars of the TPS house, jidoka and just in time (JIT).

I’ve been thinking about why jidoka and JIT are the two pillars, and why they’re not kanban or kaizen.

Jidoka was developed from the ideas of Sakichi Toyoda, father of Kiichiro Toyoda. Kiichiro Toyoda founded Toyota Motor Corp. Sakichi Toyoda invented an automatic loom that stopped immediately when the thread broke. He viewed it as automation with human intelligence. Jidoka in Japanese means “automation,” but Toyota’s jidoka includes a human character in the written script, and although it’s still pronounced “jidoka,” it now means “autonomation.”


Figure 1: The TPS house (Source: Toyota Europe website)

The emphasis of jidoka is on quality. We can view jidoka as preventing defects from being passed along or ensuring that the quality of the product is maintained as it flows through the line.

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By: Harish Jose

Shigeo Shingo is one of my heroes in industrial engineering. He had a great mind that thrived on curiosity. Today I am looking at Shingo’s Whys. This is in contrast to Taiichi Ohno’s 5 Whys method.

Ohno’s 5 Whys method is one of the tools in Toyota Production System to get to the root cause of an issue. When you see a problem, you ask, “Why did that problem happen?” When you get an answer to that question, you then ask, “Why did that problem No. 2 happen?” and so on until you get to the root cause. When you eliminate the root cause, the problem is solved.

This approach assumes a direct and linear cause-and-effect relationship. And depending on the user’s expertise and experience, you can get different results. A tool like 5 Whys is user-dependent and one-dimensional. It is appropriate for necessary causes; it may not be appropriate for sufficient causes. Its usefulness certainly diminishes as complexity increases.

Shingo’s Whys are not in relation to Ohno’s 5 Whys, but another set of questions, known as 5W1H. They are:
1. Who?
2. What?
3. Where?
4. When?
5. Why?
6. How?

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By: Harish Jose

In today’s column, I am looking at wu wei, which is an important concept detailed in the Chinese classic text, Tao Te Ching. This term is generally translated into English as wu = no, wei = action, or no action. There are other similar concepts in Taosim such as wu shin or no mind.

Alan Watts, the delightful English philosopher described wu wei as “not forcing”:
“The whole conception of nature is as a self-regulating, self-governing, indeed democratic organism. But it has a totality that all goes together, and this totality is the Tao. When we can speak in Taoism of ‘following the course of nature; following the way,’ what it means is more like this: Doing things in accordance with the grain. It doesn’t mean you don’t cut wood, but it means that you cut wood along the lines where wood is most easy to cut, and you interact with other people along lines which are the most genial. And this then is the great fundamental principle which is called wu wei, which is not to force anything. I think that’s the best translation. Some call it ‘not doing,’ ‘not acting, ‘not interfering,’ but ‘not to force’ seems to me to hit the nail on the head. Like don’t ever force a lock; you’ll bend the key or break the lock. You jiggle until it revolves.

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By: Harish Jose

As readers of my columns know, I am an ardent student of the Toyota Production System (TPS). One of the core philosophies of TPS is kaizen, often translated from Japanese as “continuous improvement.” It is the idea that one should continuously find ways to eliminate nonvalue-adding activities, and in the process develop oneself and others to get better at kaizen. The idea of kaizen begetting more kaizen.

Kaizen is a human capital enrichment philosophy. As Eiji Toyoda, Toyota Motor Corp.’s president from 1967 to 1982, said, “It is people that make things, and so people must be developed before work can start.”

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By: Harish Jose

In today’s column, I’m looking at Weber’s Law. It’s named after Ernst Heinrich Weber (born June 24, 1795, died Jan. 26, 1878), a German physician who was one of the pioneers of experimental psychology. I highly recommend the Numberphile YouTube video that explains this in detail.

A simple explanation of Weber’s Law is that we notice things more at a lower intensity than at a higher intensity. For example, the light from your phone in a dark room may appear very bright to you. At the same time, the light from your phone in a bright room may seem insignificant. This type of perception is logarithmic in nature. This means that a change from 1 to 2 feels about the same as a change from 2 to 4, or 4 to 8. The perception of change for an increment of one unit depends on whether you are experiencing it at a low intensity or a high intensity. At low intensity, a slight change feels stronger.

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By: Harish Jose

It has been a while since I have written about statistics, and I get asked a lot about a way to calculate sample sizes based on reliability and confidence levels. So today I am sharing a spreadsheet that generates an operating characteristic (OC) curve based on your sample size and the number of rejects. The spreadsheet (there's a link to it at the end of this article) should be straightforward to use. Just enter your own data in the required yellow cells.

A good rule of thumb is to use a 95-percent confidence level, which also corresponds to 0.05 alpha. The spreadsheet will plot two curves. One is the standard OC curve, and the other is an inverse OC curve. The inverse OC curve has the probability of rejection on the y axis, and the percent conforming on the x axis. These correspond to confidence level and reliability, respectively.

I will discuss the OC curve and how we can get a statement that corresponds to a reliability/confidence level from the OC curve.

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By: Harish Jose

Today I’m looking at design from a cybernetics viewpoint. My inspirations come from cybernetics and design theorists Ross Ashby, Stafford Beer, Klaus Krippendorff, Paul Pangaro, and Ranulph Glanville. I was curious about how the interface of a device conveys the message to the user on how to interact with it. For example, if you see a button, you are invited to press it. In a similar vein, if you see a dial, you know to twist it. By looking at the ideas of cybernetics, I feel that we can expand on this further.

Ross Ashby, one of the pioneers of cybernetics, defined “variety” as the number of possible elements (or states) of a system. A stoplight, for example, generally has three states—red, green, and yellow. Additional states are possible, such as blinking red, no light, or simultaneous combinations of two or three lights. Of all the possible states identified, the stoplight is constrained to have only three states. If the stoplight is not able to regulate traffic acting in tandem with similar stoplights, traffic gets congested and results in a standstill. Thus, we can say that the stoplight was lacking the requisite variety.

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By: Harish Jose

One of my favorite equations from Factory Physics, by Wallace Hopp and Mark Spearman (Waveland Press, third edition, 2011) is Kingman’s formula, usually represented as “VUT.”

The VUT equation is named after Sir John Kingman, a British mathematician:

The first factor represents variability and is a combination of variability factors representing arrival and service times (e.g., flow variability and process variability). The second factor represents utilization of the workstation or the assembly line. The third factor represents the average processing time in the workstation or the assembly line. The VUT equation shows that the average cycle time or wait time is proportional to the product of variability, utilization, and process time.

The most important lesson from VUT is: If a station increases utilization without making any other change, average work in process (WIP) and cycle time will increase in a highly nonlinear fashion.