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The sound quality design of consumer electronics spans multiple design processes, from requirement definition to functional and structural design. It is difficult to reflect customer demands depending on situations to physical design. In this paper, we introduce the evaluation grid method that assumes use cases to clarify customer demands for camera shutter sound depending on situations. To define the sound quality target, customer demands according to use cases are derived from clustering analysis of the evaluation grid test for camera shutter sound. Using domain mapping matrix, we define the relationships between use cases and requirement clusters, requirement clusters and evaluation words for sensory test, evaluation words and tonal factors. By this method, it is possible to evaluate the customer requirements depending on use cases, and define the sound quality target. In order to solve a problem in which relationship among customer requirements, functional and structural design are not clear, we propose an MDM-based representation to show the design information management from requirement definition to functional and structural design. In the requirement definition process, sound quality targets depending on use cases are defined using tonal factors. In order to systematically connect to sound quality metrics in the functional design process and to engineering metrics in the structural design process, DSM and DMM were used. The method was applied to camera shutter sound design and shows its effectiveness.

Navigation systems are nowadays widely used for cars though it is yet to be able to say popularized for motorcycles. While motorcycle navigation systems are not popularized yet, previous research indicates motorcyclist's high demand against a useful navigation system. The absence of useful motorcycle navigation system is an issue of current products not capable of providing navigation information efficiently. To work with the issue, information presentation design is necessary to consider the motorcyclist's characterful viewpoint movement of looking at the road surface carefully in a vertical movement. As a solution to this issue, we propose the use of head-up display for information presentation. Previous studies have revealed the amount and positions suitable to present information for motorcyclist while riding, although the timing of information presentation is yet to be discussed. Thus, in this paper, the information presentation timing to provide navigation information has been evaluated. Experiment using an immersive CAVE motorcycle simulator was conducted with the configuration of five timings between 25 m to 85 m prior to the intersection under conditions of urban street with 30 km/h speed limit. Durations of motorcyclist's viewpoint movement and five scale subjective ratings were used for evaluation. The experimental results from 10 subjects showed a statistically significant difference in subjective ratings. In conclusion, suitable information presentation timing of riding in urban streets with 30 km/h speed limit is around 40 m to 55 m prior to the target intersection.

Thermal design of electronic products has become increasingly complicated with leakage current characteristics and their variation of semiconductors. This paper proposes an application of a thermal system model to a production system of electronic products. The thermal system model is developed for architecture design to determine design parameters of modules. The model is described with Systems Modeling Language (SysML) considering interactions among parameters of mechanical structure and electrical components that include semiconductors with temperature-dependent leakage current characteristics. In the system model, constraints of heat generation and heat transfer are described using equations and relation between equations and parameters are clarified in parametric diagram. The system model that is developed at the early stage of product design is used at the beginning of integration, such as receiving inspection. To prevent quality degradation by variation in component characteristics, semiconductor components such as processing units are screened with thermal simulation result before their implementation on Printed Wiring Board (PWB). The simulation result is being referred to temperatures that cause low-temperature burn injury. As a case study, a system model of portable product is developed and demonstrates thermal simulation to determine limitation in large variation in leakage current characteristics to satisfy product thermal quality. To improve yield ratio of the semiconductor components after screening, system models are developed for various products in which same processing units are installed. The system model can be applied for each product changing the design parameters and simulate to determine allowable range of component characteristics keeping the product quality. Implementing a component that causes more leakage effect into a product that has more allowable range, degradation of product quality can be avoid without losing the component yield ratio.

Car navigation systems have recently become a popular assist system for automobiles. On the other hand, lack of dedicated motorcycle navigation system is still an issue. This is because currently provided navigation system utilizable for motorcycle has difficulties for riders to obtain information while driving. Recent research propose of using the head-up display technology is considered to solve this issue. Although, topics about the amount of information to provide using the head-up display has not yet been discussed. Since providing too much information distracts driving behaviors, amount of information control is required to prevent inattentive driving behaviors. To evaluate the preferable amount of information, we conducted an experiment using the immersive motorcycle simulator integrated with a head-up display. The experiment measured motorcycle riders' viewpoint movements using the eye-mark recorder to observe the duration spent against the information provided using the head-up display. Through the experiment, we presented different length of Japanese syllabary characters (Hiragana) on the head-up display to 10 subjects. Experiments results indicate presenting 5 Japanese syllabary characters is the preferable amount of information to the motorcycle rider while driving. Applying information theories, we conclude that the preferable information transmission rate is approximately 16 bits per seconds.