Machining is carried out on the assumption of machine tool stability, but machine tools do not stay in good running condition forever. They have components that deteriorate over time, sometimes causing the machine tool to break down. The machine tool may then have to be taken out of service for a lengthy time, forcing changes in plans and delays in production. Maintenance measures to prevent such occurrences include periodic replacement of components and periodic diagnosis. This study focused on the diagnosis of machining center failures. Maintenance data collected from die machining centers over a period of 11 years were analyzed. The analysis uncovered points at which failures were likely to occur, points at which periodic diagnosis is necessary, and points and components deserving priority for improvement. Specifically, the standardized variation of the failure data of each machining center was calculated, the degrees of the effects of different factors were obtained, and factors requiring attention were chosen. These results will be applied in machining center maintenance.
In recent years, bank transfer fraud has become a serious problem in Japan. In typical cases, the victim is tricked out of money by someone impersonating a family member over the phone. Japan's declining birth rate and aging population have produced a growing number of solitary elderly people who are particularly at risk. To prevent such impersonation, this paper proposes a method of identifying a speaker from normal conversational speech without relying on particular words or phrase. Specifically, power spectra were calculated from waveform data taken from normal conversational speech, using rectangular windows at 1-second intervals, and were analyzed by the RT method. This method was verified by analyzing speech waveforms differing from the unit space. As a result, the feasibility of using this method to identify a speaker from normal conversational speech was confirmed.
The purpose of this research was to develop a more user friendly LED table lamp for close range illumination by considering scenarios of use of the product as noise factors in the conceptual product development stage and thereby obtain a product with greater customer satisfaction. Virtual design was employed, permitting conceptual systems to be evaluated and selected at the conceptual stage and conceptual design to be taken to a deeper level. However,everybody evaluates user friendliness or ease of use in a different way. It was hoped that effective noise factors would enable evaluations by just a few people to represent the evaluations of many, but it was found that one person's evaluation cannot represent six people's evaluations, and that not only do evaluations vary from person to person, but some people have low reliability on the evaluation criteria axis. By excluding such people from the evaluation results, an evaluation method with high reproducibility was established, and a conceptual plan for a product considered easy for many people to use was selected. This research began when the conceptual study was initiated, but it was recognized that the method needed to be applied more widely, including the upstream product planning stage that precedes conceptual study.