• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.58-63
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• 2005

Objectives: REM sleep behavior disorder (RBD), characterized by excessive motor activity during REM sleep, is associated with loss of muscle atonia. In recent years, it has been reported that RBD has high co-morbidity with CNS disorders (especially, Parkinson's disease, dementia, multiple system atrophy, etc.). We aimed to assess differences in clinical and polysomnographic findings among RBD patients, depending on the presence or absence of central nervous system (CNS) disorders. Methods: The medical records and polysomnographic data of 81 patients who had been diagnosed as having RBD were reviewed. The patients were classified into two groups: associated RBD (aRBD, i.e., with a clinical history and/or brain MRI evidence of CNS disorder) and idiopathic RBD (iRBD, i.e., without a clinical history and/or brain MRI evidence of CNS disorder) groups. Twenty-one patients (25.9%) belonged to the aRBD group and 60 patients (74.1%) belonged to the iRBD group. The clinical characteristics and polysomnographic findings of the two groups were compared. Results: Periodic limb movement disorder (PLMD), i.e., PLMI (periodic limb movement index)>5, was observed more frequently in the aRBD group than in the iRBD group (p<0.001, Fisher's exact test). Also, obstructive sleep apnea syndrome (OSAS), i.e., RDI (respiratory disturbance index)>5, was found more frequently in the aRBD group (p=0.0042, Fisher's exact test). The percentages for slow wave sleep and sleep efficiency were significantly lower in the aRBD group than in the iRBD group. Conclusion: We found that 1 out of 4 RBD patients had associated CNS disorders, warranting more careful neurological evaluation and follow-up in this category of RBD. In this category of RBD patients, we also found more frequent PLMD and OSAS. These patients were also found to have lower slow wave sleep and sleep efficiency. In summary, RBD patients with associated CNS disorders suffer from more disturbed sleep than those without them.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• Journal of Technology Innovation
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• v.26 no.3
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• pp.37-68
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• 2018

Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.

• Journal of Music and Human Behavior
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• v.4 no.2
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• pp.84-105
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• 2007

Cerebral palsy is a collection of motor disorders resulting from damage to the central nervous system that arise in multiple handicaps including cognitive disorders, speech disorders, epilepsy, perception disorders, and emotion disorders. Today spastic cerebral palsy has become more prevalent because intensive care for newborns has resulted in higher survival rates for very small premature babies. Since the children grow the fastest in order for a development during one year after birth, the therapeutic intervention is provided as early as possible to the children with cerebral palsy. After seven year old, there is no effect of intervention. So, the necessity of early intervention to spastic cerebral palsied infants is increasing. The purpose of this study is to develop the music therapy activity program using the techniques of neurological music therapy(NMT), the therapeutic application of music to dysfunctions due to neurologic disease of the human nervous system, for rudimentary movement phase of spastic cerebral palsied infant. This music therapy activity program was developed on the basis of the major developmental tasks of the rudimentary movement phase, the period that children can acquire the most basic movement function at the 0 to 2. Then the developmental characteristics of spastic cerebral palsy were applied to this music therapy activity program. This music therapy activity program was classified to three domains, those are stability, locomotion, and manipulation. This study has been consisted of three steps, those are the development of the activities, the evaluation of the activities by th panels, and the adjustment and complement of the activities. Reviewing literatures and interviews were done for the development of the activities, and the evaluation the activities was done by seven music therapists. In the evaluation steps, the questionnaire was used for estimating the content validity and application efficiency. The adjustment and complement of the activities were evaluated by the panels who were participating in the music therapy for cerebral palsied children in the clinical setting, and the results of the adjustment and complement were confirmed by the panels. The evaluation was presented in a mean value with the comment of the panels. In conclusion, the music therapy activity program for the spastic cerebral palsied infants using the techniques of NMT was developed on the basis of the major developmental tasks of the rudimentary movement phase. The program is comprised of 38 activities, those are 14 activities for developing the stability, 10 activities for developing the locomotion, and 14 activities for developing the manipulation. The programed activities would bring out the answers in the affirmative for the conformance with infants' development phase, the harmony between the objective and the activity, the conformance with the cerebral palsied infants, the properness of the music and the instruments, and the utility in the clinic field. This results mean that this developed music activity program is appropriate to help spastic cerebral palsied infants progress their movement development by stages.