Search results for: Mitsuko Aramaki

Authors: Benjamin Bressolette, S´ebastien Denjean, Vincent Roussarie, Mitsuko Aramaki, Sølvi Ystad, Richard Kronland-Martinet

Abstract:

New sensors and technologies – such as microphones, touchscreens or infrared sensors – are currently making their appearance in the automotive sector, introducing new kinds of Human-Machine Interfaces (HMIs). The interactions with such tools might be cognitively expensive, thus unsuitable for driving tasks. It could for instance be dangerous to use touchscreens with a visual feedback while driving, as it distracts the driver’s visual attention away from the road. Furthermore, new technologies in car cockpits modify the interactions of the users with the central system. In particular, touchscreens are preferred to arrays of buttons for space improvement and design purposes. However, the buttons’ tactile feedback is no more available to the driver, which makes such interfaces more difficult to manipulate while driving. Gestures combined with an auditory feedback might therefore constitute an interesting alternative to interact with the HMI. Indeed, gestures can be performed without vision, which means that the driver’s visual attention can be totally dedicated to the driving task. In fact, the auditory feedback can both inform the driver with respect to the task performed on the interface and on the performed gesture, which might constitute a possible solution to the lack of tactile information. As audition is a relatively unused sense in automotive contexts, gesture sonification can contribute to reducing the cognitive load thanks to the proposed multisensory exploitation. Our approach consists in using a virtual object (VO) to sonify the consequences of the gesture rather than the gesture itself. This approach is motivated by an ecological point of view: Gestures do not make sound, but their consequences do. In this experiment, the aim was to identify efficient sound strategies, to transmit dynamic information of VOs to users through sound. The swipe gesture was chosen for this purpose, as it is commonly used in current and new interfaces. We chose two VO parameters to sonify, the hand-VO distance and the VO velocity. Two kinds of sound parameters can be chosen to sonify the VO behavior: Spectral or temporal parameters. Pitch and brightness were tested as spectral parameters, and amplitude modulation as a temporal parameter. Performances showed a positive effect of sound compared to a no-sound situation, revealing the usefulness of sounds to accomplish the task.

Keywords: auditory feedback, gesture sonification, sound perception, virtual object

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Authors: K. Yuki, R. Tsuji, K. Takai, S. Aramaki, R. Kibushi, N. Unno, K. Suzuki

Abstract:

A small cold plate with uni-directional porous copper is proposed for cooling power electronics such as an on-vehicle inverter with the heat generation of approximately 500 W/cm2. The uni-directional porous copper with the pore perpendicularly orienting the heat transfer surface is soldered to a grooved heat transfer surface. This structure enables the cooling liquid to evaporate in the pore of the porous copper and then the vapor to discharge through the grooves. In order to minimize the cold plate, a double flow channel concept is introduced for the design of the cold plate. The cold plate consists of a base plate, a spacer, and a vapor discharging plate, totally 12 mm in thickness. The base plate has multiple nozzles of 1.0 mm in diameter for the liquid supply and 4 slits of 2.0 mm in width for vapor discharging, and is attached onto the top surface of the porous copper plate of 20 mm in diameter and 5.0 mm in thickness. The pore size is 0.36 mm and the porosity is 36 %. The cooling liquid flows into the porous copper as an impinging jet flow from the multiple nozzles, and then the vapor, which is generated in the pore, is discharged through the grooves and the vapor slits outside the cold plate. A heated test section consists of the cold plate, which was explained above, and a heat transfer copper block with 6 cartridge heaters. The cross section of the heat transfer block is reduced in order to increase the heat flux. The top surface of the block is the grooved heat transfer surface of 10 mm in diameter at which the porous copper is soldered. The grooves are fabricated like latticework, and the width and depth are 1.0 mm and 0.5 mm, respectively. By embedding three thermocouples in the cylindrical part of the heat transfer block, the temperature of the heat transfer surface ant the heat flux are extrapolated in a steady state. In this experiment, the flow rate is 0.5 L/min and the flow velocity at each nozzle is 0.27 m/s. The liquid inlet temperature is 60 °C. The experimental results prove that, in a single-phase heat transfer regime, the heat transfer performance of the cold plate with the uni-directional porous copper is 2.1 times higher than that without the porous copper, though the pressure loss with the porous copper also becomes higher than that without the porous copper. As to the two-phase heat transfer regime, the critical heat flux increases by approximately 35% by introducing the uni-directional porous copper, compared with the CHF of the multiple impinging jet flow. In addition, we confirmed that these heat transfer data was much higher than that of the ordinary single impinging jet flow. These heat transfer data prove high potential of the cold plate with the uni-directional porous copper from the view point of not only the heat transfer performance but also energy saving.

Keywords: cooling, cold plate, uni-porous media, heat transfer

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Authors: Adino Andaregie, Isao Takagi, Hirohisa Shimura, Mitsuko Chikasada, Shinjiro Sato, Solomon Addisu

Abstract:

Context: The prevalence of undernutrition in developing countries like Ethiopia has become a significant issue. In this regard, finding alternative nutritional supplements seems to be a practical solution. Spirulina, a highly nutritious microalgae, offers a valuable option as it is a rich source of various essential nutrients. The study aimed to establish the factors affecting urban Ethiopian consumers' consumption intention of Spirulina-fortified bread. Research Aim: The primary purpose of this research is to identify the behavioral and socioeconomic factors impacting the intention of urban Ethiopian consumers to eat Spirulina-fortified bread. Methodology: The research utilized a quantitative approach wherein a structured questionnaire was created and distributed among 361 urban consumers via an online platform. The theory of planned behavior (TPB) was used as a conceptual framework, and confirmatory factor analysis (CFA) and structural equation modelling (SEM) were employed for data analysis. Findings: The study results revealed that attitude towards the supplement, subjective norms, and perceived behavioral control were the critical factors influencing the consumption intention of Spirulina-fortified bread. Moreover, age, physical exercise, and prior knowledge of Spirulina as a food ingredient were also found to have a significant influence. Theoretical Importance: The study contributes towards the understanding of consumer behavior and factors affecting the purchase intentions of Spirulina-fortified bread in urban Ethiopia. The use of TPB as a theoretical framework adds a vital aspect to the study as it provides helpful insights into the factors affecting intentions towards this functional food. Data Collection and Analysis Procedures: The data collection process involved the creation of a structured questionnaire, which was distributed online to urban Ethiopian consumers. Once data was collected, CFA and SEM were utilized to analyze the data and identify the factors impacting consumer behavior. Questions Addressed: The study aimed to address the following questions: (1) What are the behavioral and socioeconomic factors impacting urban Ethiopian consumers' consumption intention of Spirulina-fortified bread? (2) To what extent do attitude towards the supplement, subjective norms, and perceived behavioral control affect the purchase intention of Spirulina-fortified bread? (3) What role does age, education, income, physical exercise, and prior knowledge of Spirulina as a food ingredient play in the purchase intention of Spirulina-fortified bread among urban Ethiopian consumers? Conclusion: The study concludes that attitude towards the supplement, subjective norms, and perceived behavioral control are significant factors influencing urban Ethiopian consumers’ consumption intention of Spirulina-fortified bread. Moreover, age, education, income, physical exercise, and prior knowledge of Spirulina as a food ingredient also play a significant role in determining purchase intentions. The findings provide valuable insights for developing effective marketing strategies for Spirulina-fortified functional foods targeted at different consumer segments.

Keywords: spirulina, consumption, factors, intention, consumers, behavior

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