789 research outputs found

    Tracking Control for FES-Cycling based on Force Direction Efficiency with Antagonistic Bi-Articular Muscles

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    A functional electrical stimulation (FES)-based tracking controller is developed to enable cycling based on a strategy to yield force direction efficiency by exploiting antagonistic bi-articular muscles. Given the input redundancy naturally occurring among multiple muscle groups, the force direction at the pedal is explicitly determined as a means to improve the efficiency of cycling. A model of a stationary cycle and rider is developed as a closed-chain mechanism. A strategy is then developed to switch between muscle groups for improved efficiency based on the force direction of each muscle group. Stability of the developed controller is analyzed through Lyapunov-based methods.Comment: 8 pages, 4 figures, submitted to ACC201

    Game-based evacuation drill using augmented reality and head-mounted display

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    Purpose–Evacuation drills should be more realistic and interactive. Focusing on situational and audio-visual realities and scenario-based interactivity, we have developed a game-based evacuation drill (GBED) system that presents augmented reality (AR) materials on tablet computers. Our current research purpose is to improve visual reality (AR materials) in our GBED system. Design/methodology/approach–Our approach is to develop a new GBED system that superimposes digital objects (e.g. 3DCG elements) onto real-time vision using a marker-based AR library, a binocular opaque head-mounted display (HMD) and other current easily available technologies. Findings–Our findings from a trial experiment are that the new GBED system can improve visual reality and is appropriate for disaster education. However, a few problems remain for practical use. Research limitations/implications–When using the GBED system, participants (i.e. HMD wearers) can suffer from 3D sickness and have difficulty in moving. These are important safety problems in HMD-based systems. Social implications–The combination of AR and HMDs for GBEDs (i.e. integrating virtual and real worlds) will raise questions about its merits (pros and cons). Originality/value–The originality of our research is the combination of AR and an HMD to a GBED, which have previously been realized primarily as simulation games in virtual worlds. We believe that our research has the potential to expand disaster education

    Tsunami Evacuation Drill System Using Smart Glasses

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    Evacuation drills are commonly conducted as traditional disaster education to reduce damages from natural disasters. However participants are not always interested in or committed to such drills. To improve this situation, we focused on Edutainment and proposed game-based evacuation drill (GBED) using the Real-World Edutainment (RWE) program. There are two types of GBED systems, i.e. the Tablet-based GBED (T-GBED) and the AR and HMD-based GBED (AH-GBED). We conducted GBED at several schools and determined that it can improve student motivation for disaster prevention. Subduction-zone earthquakes frequently generate tsunamis and can cause catastrophic damage especially to coastal areas. Thus people in coastal areas must move very quickly to evacuation sites when a massive earthquake occurs. Both GBED systems cannot be used directly for tsunami evacuation drills because the participants will not want to sprint while holding a tablet or wearing a HMD and have time to stop to view the digital materials. In this study, we propose a tsunami evacuation drill (TED) and have developed a TED system. The TED system uses smart glasses (a lightweight optical see-through HMD) which allows participants to view digital materials while moving quickly

    Effects of Ground Improvement and Armored Embankment to the Displacements of the Seawalls and Back Fill During Earthquake

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    Large shaking table tests of the caisson type seawalls under various conditions were conducted in order to investigate the effects of the armored embankment and the improvement of sandy seabed and backfill by densification to the deformation of the seawalls during earthquake. Main results obtained from the shaking table tests were as follows : (1) Seaward horizontal displacement and tilting of the caisson were drastically reduced by the existence of the armored embankment in front of the caisson. (2) Improvement of the sandy seabed by densification method just under the rubble mound was much effective to reduction of the displacements of the caisson. (3) It was possible that the lateral movement of the liquefied backfill was reduced by the improvement of a part of the backfill just behind the caisson even though without the armored embankment in front of the caisson

    Cardiorespiratory fitness and the incidence of type 2 diabetes: a cohort study of Japanese male athletes

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    BACKGROUND: In Japan, although the incidence of overweight (BMI ≥ 25) is still low compared with that in Europe and the United States, the prevalence of type 2 diabetes has increased over the last 15 years,. In both Japanese and Caucasian populations it has been reported that a high level of cardiorespiratory fitness protects against the development of type 2 diabetes. However, there are no reports focused specifically on athletes that investigate whether high cardiorespiratory fitness at a young age can prevent disease later in life. We examined the relationship between cardiorespiratory fitness at a young age and the development of type 2 diabetes in Japanese athletes using a cohort study. METHODS: The cardiorespiratory fitness of male alumni of the physical education department of Juntendo University, as measured by stored data of a 1,500-m endurance run in college (1971–1991) was compared with their incidence of type 2 diabetes as determined by follow-up questionnaires (2007–2009). This study used Cox’s proportional hazards models and adjusted for age, year of graduation, BMI, smoking, and sports club participation at college age. RESULTS: We collected data on cardiorespiratory fitness at college age and medical history survey data during 2007–2009 from 570 male alumni. The median follow-up period was 26 years (IQR: 23–29 years), and 22 men had developed type 2 diabetes. An inverse relationship was observed between incidence of type 2 diabetes and level of cardiorespiratory fitness at time of college after adjustment for age, year of graduation, BMI, smoking, and sports participation. The adjusted hazards ratio and 95% CI by category (low, medium, and high) were 1.00 (reference), 0.40 (0.14–1.13) and 0.26 (0.07–1.00) (p = 0.03 for trend). CONCLUSIONS: A high level of cardiorespiratory fitness at a young age can help prevent type 2 diabetes later in life

    CLINICOPATHOLOGICAL STUDY OF CEREBRAL SUBCORTICAL CAVERNOUS ANGIOMA AS EPILEPTOGENIC FOCUS

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    The authors conducted a comparative histological study of two groups of patients with cerebral subcortical cavernous angioma. One group was composed of 5 asymptomatic cases detected accidentally. The other group was composed of 4 patients presenting as epilepsy. The results obtained may be summarized as follows ; 1) Hemosiderin deposit and gliosis were seen in all cases examined ; 2) Granulomatous change was a histological finding associated with epileptogenesis ; 3) The histological changes, starting with proliferation of collagen fibers and leading to hyaline degeneration, calcification, and then hemangioma calcificans, seem to represent a course of spontaneous healing, when viewed from epileptogenesis
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