Research using the MT method to study foot-bath effect has shown Kampo bath salts to be highly effective. They are, however, expensive because of their use of herbal medicines. In this study, the herbal composition ratio was varied and it was found that there exists a composition ratio with lower cost but greater effect. States thought from everyday experience to represent conditions of low fatigue were taken as the unit space, and states distanced in the MT system by intentionally adding fatigue were taken as the signal space. The study covered physical condition, lifestyle, and Kampo questionnaire data. The effect of bath salts was optimized from the degree to which foot baths reduced the distance of the signal space, by studying the sensitivity β and the S/N ratio of the reciprocal of the error variance. Enlarging on these results, it appears possible to use the MT system to evaluate drug effect and find appropriate prices.

In the past, the chemical resistance of materials for applications such as elastic waterproof coatings has been evaluated comprehensively on the basis of tensile strength, change in weight, change in dimension, etc. These changes can only be detected if the chemical soaks into the entire coating, so the evaluation requires a long immersion time. The authors conjectured that the immersion time could be considerably shortened by using a microhardness gauge to measure the elasticity of approximately the top 20μm of the coating. This test method was used in the parameter design of a new elastic waterproof coating material of the type that is obtained by reaction curing of a two-liquid mixture of a solventless base compound and a curing agent. As a result, a test that would previously have taken several months was shortened to one week (one-twelfth of the previous time), and a product with much better chemical resistance than previous products was developed. This method is of great value in that it is widely applicable to the development of elastic waterproof coating materials.

The previous report described a stability study in which a flow rate v. pressure ratio curve obtained from simulation was used as an evaluation index. As a result of iterative optimization a large gain was obtained from a series of smaller gains. Study of the parameter design results at each iteration also clarified such issues as level ranges and system selection. Reproducibility was obtained by resolving these issues, leading to a compressor with a higher pressure ratio and higher efficiency. Further improvements on the basis of this index, however,turned out to be difficult, and there were also tuning problems. An iterative optimization was therefore performed using the input-output energy relationship in the basic function as the evaluation index. This led to higher gain, and the tuning problem was solved through parallel use of the results of the flow rate v. pressure ratio curve. Through these studies we established a method of applying quality engineering to the design of centrifugal compressors, which we report here.

Studying the feasibility of setting up a new company is a complex proposition. Many factors affect the new company's profitability, and it is not unusual for a feasibility study to go through more than 100 trial iterations. Robust design (with two-step optimization) was therefore applied to the feasibility study process. The generic function was the cumulative profit-and-loss function over time. This function was first stabilized by use of the standard signal-to-noise ratio, then tuned to the target function. The results showed that it is possible to select the best factors by this two-step optimization process. The same method can also be usefully applied to new five-year strategic management plans for existing companies.

In an article in the Nikkan Kogyo newspaper on March 22, 2002, Shigeru Tai reported the successful use of on-line quality engineering by Mazda in starting a new production process. The impact of this article on the spread of quality engineering was substantial. Quality engineehng also occupies a central position in the probability and statistics curriculum at the School of Science and Engineering at Tokyo Denki University. The above article was distributed to students taking this course, who were asked to write reports about it. The authors read the reports, distributed the results back to the students, and asked for a second report. What came out of this cyclic interchange were new discoveries that resulted from stimulating contact between a school, an enterprise, and a newspaper, three parties among which there would normally be no contact at all. By recording this process and studying its meaning, this study clarifies the social significance of the quality engineering paradigm shift. First, prerequisite material is presented; then the opinions exchanged among the three parties during the interaction process are presented, showing the reactions that took place over time. The conclusion is that exchanges between different fields hold the possibility of creating a new basis for the development of quality engineering.

Instead of applying quality engineering (QE) only in the upstream development and design work, we have tried applying its concepts and methods to all engineering activities in a company. Our ultimate aim in this methodological study is to renovate our corporate culture. Using Alps Electric Co., Ltd., which employs QE in all its corporate activities, as a benchmark, and taking account of the differences between their business and ours, we have devised our own methodology for company-wide QE deployment. This work is proceeding as a project under the direct supervision of the company president, using specific themes involved in the commercialization of new products. This paper presents tentative results and discusses remaining problems.