Masaya Miyagi

Uninterruptible smart house using the active and reactive power instantaneous value control

A smart house must avoid power supply interruption because power supply is very important for an all-electric house. Therefore, a smart house needs uninterruptable power features. The proposed uninterruptible all-electric smart house has seamless features for stand-alone mode, phase synchronization control and grid-connected mode using instantaneous active and reactive power value calculated using a single-phase dq transformation system. Also, this smart house achieves a reduction of the transient current at the transition from standalone mode to grid-connected mode by phase synchronization control. The effectiveness of the proposed method is verified by simulation results given by the Matlab/SimPowerSystems environment.

Advanced Smart House with an electric vehicle

Since the Great East Japan Earthquake, many people have been worried about power shortages in Japan. There has been more focuses to the save electricity at home. A method is very important that can reduce the energy requirement without any trouble to the home people. The spread of PV (Photovoltaic) will be expanded by the surplus power buy back institution, and Smart House with HEMS is expected to save the electricity. Therefore, studies and verification tests of a smart house are very effective. The stand-alone capability in the conventional PV system does not work well in a natural disaster. The reason is that the conventional stand-alone capability is needed to switch by manual when switching to the stand-alone mode and it is only able to supply power to the limited plugs. In addition, transferring stand-alone mode to the grid-connected mode is needed to switch by manually. It needs an effective and a safe stand-alone capability of PV system at home that can ensure power stability during the disaster like the typhoons and earthquakes. This paper describes a disaster prevention and energy management system for a smart house. The effectiveness of the proposed smart house is verified by computer simulations on Matlab/SimPower systems® environment.

Decentralized controllable loads control in small power system

In recent years, amount of renewable energy facilities using wind turbine generator and photovoltaic power system have been increased due to natural environment and resource depletion. Moreover, all electrification apartment houses or residences and electric vehicles have been increased. However, due to the fluctuating power from renewable energy sources and loads, fluctuations of grid frequency and distributed voltage become problematic. This paper presents a methodology of control system frequency and distributed voltage by distributed controllable loads such as heat pump and electric vehicles. By applying power consumption controller using distribution control for heat pump water heater (HP) and droop characteristics for battery, fluctuations of grid frequency and voltage are suppressed around desired value. In order to verify the effectiveness of the proposed system, MATLAB/Simulink is used for simulations.

Unnecessary Dieting Intention and Behavior among Female Students in Naha City, Japan

Weight concerns and dieting are prevalent among female adolescents both in Western and Asian countries. They can result in negative psychological and physiological consequences. This study aimed to examine the relative importance of social and personal factors in the decision to diet among female adolescent students in Japan, applying the Theory of Planned Behavior. Data were collected from five junior high schools and three high schools in Naha City, Okinawa Prefecture, in 2010, through self-administered questionnaires. The data of 756 female students were assessed. The independent variables included social factor variables (norms) and personal factor variables (attitude to dieting, perceived behavior control, body esteem, body-figure discrepancy and past dieting). The dependent variables were dieting intention and behavior. Hierarchical multiple regression analyses were performed to examine three models: model 1 (age and obesity index), model 2 (social factor variables with age and obesity index) and model 3 (all variables). Although model 2 failed to explain a substantial proportion of the variance, model 3 explained approximately a half of the variance for intention (R2 = 0.507) and more than one third of the variance for behavior (R2 = 0.376). Past experience of dieting was the best predictor of both dieting intention and behavior. Body esteem was the second best predictor for dieting behavior. In conclusion, personal factors are more likely than social factors to drive the dieting decision. Diet education programs should consider targeting frequent dieters and those with poor body esteem.

Optimal load sharing using droop control and fuzzy control in uninterruptible smart house

Currently, use of the electric vehicle (EV) has begun to spread rapidly and there is a possibility that the EV can be connected with the smart house to control charging or discharging operations. In this case, the smart house has to perform optimal load sharing control according to the state of charge of the storage battery and the battery capacity. In this paper, a method of optimal load sharing using droop control and fuzzy control is proposed for a smart house which is equipped with a PV system, EV, storage battery, and HEMS. Optimal load sharing is achieved by changing the droop characteristics of the each inverters which connected to the PV system, storage battery, and EV by using fuzzy control. The effectiveness of the proposed method is verified by simulation results in the Matlab®/SimPowerSystems environment.

Uninterruptable all-electrification smart house

Smart house has to avoid interruption of power supply because power supply is more important for electrification house. Therefore, smart house needs uninterruptable power features. The proposed uninterruptable electrification smart house has seamless features for stand-alone mode, phase synchronization operation and grid-connected mode by phase synchronization control. Also, this smart house achieves reduction of the transient current at transition condition from stand-alone mode to grid-connected mode. The effectiveness of the proposed method is verified by simulation results in Matlab/Sim Power Systems environment.

Does Physical Fitness Affect Academic Achievement among Japanese Adolescents? A Hybrid Approach for Decomposing Within-Person and Between-Persons Effects

Positive association between physical fitness and academic achievement in adolescents has been suggested yet the causal effect of physical fitness on academic achievement remains unclear. This study examined if longitudinal changes in physical fitness were associated with changes in academic achievement among junior high school students. Analyses were based on a two-year with three time-point data of 567 students (aged 12–13 years old at the baseline-point; 303 boys) who entered in five Japanese junior high schools in 2015. Academic achievement was evaluated using the student’s overall grade point average. Comprehensive physical fitness score was summed up from eight fitness tests: 50-m sprint, standing broad jump, repeated side-steps, sit and reach, sit-ups, hand-grip strength, handball throw, and 20-m shuttle run or endurance run. The hybrid regression model was applied to examine the impact of change in physical fitness on change in academic achievement using multiple imputation to account for non-response at follow-up. The changes in fitness score within-person and the differences in average of fitness score of three-time points between-person were associated with change in overall grade point average for boys. No significant association between fitness score and overall grade point average was observed in girls. Opportunities for increased physical fitness may be important to support academic achievement, particularly in junior high school boys.

FRT capability for multiple inverters in an uninterruptible smart house

Recently, the smart house, which is equipped with a residential photovoltaic (PV) system, storage battery, and Home Energy Management System (HEMS) has attracted much attention. For power system stability the PV system requires a Fault Ride Through (FRT) function. The smart house proposed in this paper performs one-second FRT control and operates in stand-alone mode at the occurrence of a distribution system fault while taking into account the battery capacity. The effectiveness of the proposed method is verified by simulation results in the Matlab/SimPowerSystems environment.