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박대권(Park Dae-Gwon),박창범(Park Chang-Beum) 한국체육과학회 2006 한국체육과학회지 Vol.15 No.4
The purpose of this study was to identify the reality of physical educational evaluation in elementary school. To achieve the purpose of this study, the opened questionnaire and interview were used. The participants(N=8) were recruited via the purposive sampling method from galam elementary school(a fictitious name) in Dae gu. the data were analyzed by the inductive content analysis method. The conclusions are as follows. First, the participants perceived the physical educational evaluation as a degree of movement skill development Second, the teachers performed the result-centered evaluation of movement skills without any definite evaluation scales and standards. Third, the teachers performed cognitive evaluation by paper pencil test at the end of school term. Fourth, the teachers performed affective domain evaluation by observation. Fifth, teachers said the obstacles of evaluation are the deficiency of special knowledges and skills in physical education, the overcrowded class, insufficient facilities and equipments.
Predictive Control Algorithm Including Conduction-Mode Detection for PFC Converter
Park, Jin-Hyuk,Kim, Dae Joong,Lee, Kyo-Beum IEEE 2016 IEEE transactions on industrial electronics Vol.63 No.9
<P>This paper proposes a predictive control algorithm that includes conduction-mode detection for power factor correction (PFC) converter. In PFC converters, the line current is usually distorted because of the characteristics of the proportional-integral (PI) current controller. To improve the quality of the current, the PI current controller requires additional circuits or algorithms. However, because of the optimal duty cycle determined by estimating the next-state current in both the continuous-conduction mode and the discontinuous-conduction mode, the proposed predictive control method has a fast dynamic response and accuracy compared to the PI current-control method. Moreover, the proposed algorithm can detect the conduction mode without any additional circuitry or mode-detection algorithm using the characteristic of the optimal duty cycle calculated by the predictive control. These advantages of the proposed algorithm improve the quality of the line current for PFC converters. We verify the proposed method by performing experiment using a 1.5-kW PFC converter.</P>
Park, Mi-Ri-Nae,Hyun, Kyung-Yae,Moon, Seong-Min,Kim, Yun-Tae,Kim, Dae-Sik,Kang, Shin-Beum,Choi, Seok-Cheol The Korean Society for Biomedical Laboratory Scien 2008 Journal of biomedical laboratory sciences Vol.14 No.4
The present study was designed to clarify whether scuba diving at 5 meters of seawater influences cerebral hemodynamics, hematological and biochemical variables. Twenty healthy young men well trained scuba diving participated in this study. The blood flow velocity in the right and left middle cerebral arteries (L-MCAV and R-MCAV), blood pressure (BP), heart rate (HR), CBC and differential count, prothrombin time (PT), activated partial thromboplastin time (aPTT), biochemical variables, D-dimer and interleukin-8 (IL-8) levels were determined before, immediately after scuba diving for 30 min, and after 30 min of rest (Pre-scuba, Scuba and R-30m, respectively). L-MCAV and R-MCAV tended to increase, but the only significant increase was in L-MCAV in Scuba. SBP and HR significantly declined in R-30m compared with those of Pre-scuba and the Scuba. IL-8 levels were elevated in Scuba and R-30m compared with that of Pre-scuba. In Scuba and R-30m, hematological variables except PT and biochemical parameters excluding glucose and lactic acid did not significantly changed in comparison with those of Pre-scuba. PT level at Scuba and glucose level at R-30m significantly declined in Scuba, while lactate level at R-30m increased compared with each in Pre-scuba. However, PT level at Scuba was within a normal range. These results suggest that scuba diving at 5 m of seawater for 30 min has no adverse effects, is safe and useful for improving health. However, further study must be performed to clarify the mechanism of elevated IL-8 level following scuba diving.
Scheme to Improve the Line Current Distortion of PFC Using a Predictive Control Algorithm
Dae Joong Kim,Jin-Hyuk Park,Kyo-Beum Lee 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5
This paper presents a scheme to improve the line current distortion of power factor corrector (PFC) topology at the zero crossing point using a predictive control algorithm in both the continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The line current in single-phase PFC topology is distorted at the zero crossing point of the input AC voltage because of the characteristic of the general proportional integral (PI) current controller. This distortion degrades the line current quality, such as the total harmonic distortion (THD) and the power factor (PF). Given the optimal duty cycle calculated by estimating the next state current in both the CCM and DCM, the proposed predictive control algorithm has a fast dynamic response and accuracy unlike the conventional PI current control method. These advantages of the proposed algorithm lower the line current distortion of PFC topology. The proposed method is verified through PSIM simulations and experimental results with 1.5 kW bridgeless PFC (BLPFC) topology.
장기적 트립토판 결여식이 생쥐의 유해감각예민도에 미치는 영향
서영대,박제민,김명정,전명호,양구범,장세헌,강철중,김정태,김용식 대한생물치료정신의학회 2000 생물치료정신의학 Vol.6 No.1
The depressive patients can be divided into two subgroups by presence and absence of pain symptoms. Those without pain symptoms have blunted pain sensitivity whereas those with pain have normal range of pain sensitivity, and are clinically characterized by anxiety and irritability. The aim of the study is to test if these clinical profiles of the depressives with pain symptoms are related with reduced level of brain serotonin(5-HT). Forty four mice were randomly divided into two groups : one group to be bred with tryptophan free diet and the other with normal control diet, each for 4 weeks. Before the beginning of the breeding period, measured were locomotor activity by open field test, anxiety by elevated plus maze and nociceptive sensitivity by tail flick test, before and after forced swimming(FS). During each FS, duration of immobilization was also measured. The sable sets of measurements were repeated at the end of the breeding period. The brain 5-HT and 5-hydroxyindoleacetic acid(5-HIAA) were measured by high performance liquid chromatography. The results were as follows 1.Four weeks of tryptophan free diet reduced significantly body weight, brain weight, and levels of 5-HT and 5-HIAA in the whole brain. 2.Tryptophan depletion did not influence basal nociceptive sensitivity as measured by tail flick latency before FS. The normal blunting of the pain sensitivity induced by forced swimming was preserved in the tryptophan depleted group. 3.Tryptophan depletion did not influence general locomotor activity in open field. 4.Tryptophan depletion increased significantly time spent on the open arms at the elevated plus maze test done before FS. This anxiolytic-like effect was reduced by FS. 5.Tryptophan depletion did not influence duration of immobilization during FS. From these results, it is suggested that the genesis of the depression with pain symptoms is not medicated by quantitative reduction of brain serotonin
효율적인 메모리구조를 적용한 M2M 네트워크상의 미들웨어 시스템 구현
박범수(Beum-Su Park),김태용(Tae-Yong Kim),이승현(Seung-Hyun Lee),임호섭(Ho-Seob Lim),강대성(Dae-Seong Kang) 한국정보기술학회 2015 한국정보기술학회논문지 Vol.13 No.4
In this paper describes, we structures that occur a decline of performance on implementing a middleware for collecting data in M2M network and analyze the integrity of the data. Then, we test middleware system using improved structure of the proposed middleware techniques in the last paper. Races between many threads to save data in database gathering information. The thread created by the middleware can make performance degradation and can break the data integrity. Thats why this paper implement middleware memory structure to mitigate the contention and improve data integrity. And this paper experimented proposed middleware memory system. Finally, this study proves the integrity of the data having a middleware system proposed by analyzing the results of the test structure.
넓은 충전 범위를 갖는 전기 자동차용 급속 충전기의 고효율 운전을 위한 손실 분석
김대중(Dae Joong Kim),박진혁(Jin-Hyuk Park),이교범(Kyo-Beum Lee) 대한전기학회 2014 전기학회논문지 Vol.63 No.8
Power losses of a 1-stage DC-DC converter and 2-stage DC-DC converter are compared in this paper. A phase-shift full-bridge DC-DC converter is considered as 1-stage topology. This topology has disadvantages in the stress of rectifier diodes because of the resonance between the leakage inductor of the transformer and the junction capacitor of the rectifier diode. 2-stage topology is composed of an LLC resonant full-bridge DC-DC converter and buck converter. The LLC resonant full-bridge DC-DC converter does not need an RC snubber circuit of the rectifier diode. However, there is the drawback that the switching loss of the buck converter is large due to the hard switching operation. To reduce the switching loss of the buck converter, SiC MOSFET is used. This paper analyzes and compares power losses of two topologies considering temperature condition. The validity of the power loss analysis and calculation is verified by a PSIM simulation model.
Scheme to Improve the Line Current Distortion of PFC Using a Predictive Control Algorithm
Kim, Dae Joong,Park, Jin-Hyuk,Lee, Kyo-Beum The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5
This paper presents a scheme to improve the line current distortion of power factor corrector (PFC) topology at the zero crossing point using a predictive control algorithm in both the continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The line current in single-phase PFC topology is distorted at the zero crossing point of the input AC voltage because of the characteristic of the general proportional integral (PI) current controller. This distortion degrades the line current quality, such as the total harmonic distortion (THD) and the power factor (PF). Given the optimal duty cycle calculated by estimating the next state current in both the CCM and DCM, the proposed predictive control algorithm has a fast dynamic response and accuracy unlike the conventional PI current control method. These advantages of the proposed algorithm lower the line current distortion of PFC topology. The proposed method is verified through PSIM simulations and experimental results with 1.5 kW bridgeless PFC (BLPFC) topology.