A study of the optimization of high-speed cutting conditions for machining the hypoid gears used in the differential units of automobiles was performed. In the past, as the tooth-cutting of hypoid gears is very complex, machining conditions were evaluated by repeatedly testing separate factors and evaluating the condition of the cutting tool and the cutting accuracy. In this study, we attempted to break away from the conventional evaluation method by performing parameter design. An initial evaluation was performed using electric power consumption and the amount of metal removed as intrinsic functions. However, as the cutting mechanism differs from the mechanism in general machining, a new type of analysis which can clearly express the machining characteristics was proposed. In this analysis, the mechanism was examined in terms of how the cutting tool and the object to be cut make contact, noting that the cutting load varies and that cutting is performed intermittently, and these two properties were reflected in the parameter design. The results demonstrated the effectiveness of this approach, providing one example of a versatile method that is applicable not only to gear machining but also to the machining of various cutting tool shapes and various machining mechanisms.
In a series of agricultural experiments using quality engineering that started in 2008, field-grown sweet potatoes were studied for two years and greenhouse-grown shiitake mushrooms were studied for one year, but the produce was evaluated only at harvest and not while growing. In the present study, corn was cultivated in planter boxes in the early stage of growth (from seeds to seedlings) and then transplanted to ridges in a field under conditions set according to an L18 orthogonal array. Growth data such as height of seedlings and size of sprouts were measured in the field, and the MT system was used to diagnose the harvested corn by analyzing noise factors, control factors, and growth data during cultivation, using the number of kernels as the characteristic value. In addition, the cultivation conditions were optimized through parameter design. From the MT analysis and parameter design, while elucidating the optimal cultivation conditions it was possible to discover, to some extent, what parts of the plants to observe and when to observe them in deciding whether to thin the plants out or cultivate them intensively. It is expected that this evaluation method, using both the MT system and parameter design, will contribute greatly to the improvement of agricultural cultivation techniques.
Chemical hazards are too various for anyone to understand thoroughly; consumers want information that can be grasped as intuitively as possible and has a degree of guaranteed reliability. To create a comprehensive index for evaluating the properties of chemical substances, the use of a calculated distance as a hazard index was studied within the MT system (variation pressure). Results from the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) were taken as the properties of approximately 1900 chemical substances for which information was provided by Japan's GHS Inter-ministerial Committee. A unit space of low-hazard substances was constructed. How the index was affected by the assignment of numerical values to individual hazards and by the handling of unclassifiable substances or substances with unknown properties, equivalent to missing data, was studied. The resulting chemical hazard index provides easy recognition of hazard level as a number, avoids underestimating the hazards of largely unclassifiable substances with unknown properties, and gives weight to the key hazards, even though GHS weights individual items similarly.
Although unauthorized access via the Internet and other communication media has become a crime punishable under law, such crimes are increasing, and taking security countermeasures is considered important. One security measure is keystroke authentication, a biometric method that uses features of personal dynamics that are hard for another person to imitate. The advantage of this method is that simple and easy user authentication becomes possible just by adding software. However, a person's keystroke dynamics can vary greatly,making it difficult to find features and identify the person. In this study, the MT system was applied to the evaluation of keystroke dynamics in an attempt to authenticate a user by using differences between the user's keystroke patterns and other people's patterns. As a result, it became possible to identify differences in typing skills from pattern distances. The losses from false positive and false negative authentication and the break-even point of the loss function were also considered, and threshold values using a digital standardized S/N ratio were studied.