• Title/Summary/Keyword: Team efficiency

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Examining the Relationship among Organizational Justice, Athlete Satisfaction, Team Commitment, and Organizational Citizenship Behavior in College Athletes

  • Keunsu HAN;Jaehyun HA
    • Journal of Sport and Applied Science
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    • v.8 no.1
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    • pp.1-10
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    • 2024
  • The purpose of this study was to examine the structural relationship among organizational justice, athlete satisfaction, team commitment, and organizational citizenship behavior toward college athletes. To achieve this purpose, this study employed a convenience sampling method via a questionnaire dissemination. A total of 285 responses were collected from college athletes. Among those, 21 responses were excluded as they were not completed, leaving 264 usable data. The data was computed in SPSS 28.0 and AMOS 28.0, and analyzed with correlation analysis, reliability analysis, confirmatory factor analysis, and structural equation modeling analysis. Overall, organizational justice had a positive influence on athlete satisfaction, team commitment, and organizational citizenship behavior. Athlete satisfaction had a positive influence on team commitment and organizational citizenship behavior. However, there was no relationship between team commitment and organizational citizenship behavior. These findings provided empirical foundational data on the impact of organizational justice on psychological and behavioral outcomes and the overall efficiency and effectiveness of organizations, with a focus on college athletes who played a central role in the context of college sports setting.

Emission Characteristic for High Efficiency and Low NOx of Externally Oscillated Oil Burner (외부가진 오일 버너의 고효율 저 NOx 배출특성)

  • Kim, Seong-Cheon;Song, Hyoung-Woon;Chun, Young-Nam
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.5
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    • pp.693-700
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    • 2006
  • The important factor for the development of burner is the achievement of low emissions with maintaining combustibility. In case of maintaining high temperature flame and excess air to increase the combustibility, it is possible to achieve high combustion efficiency, due to the reduction of UHC(unborn hydrocarbon), carbon monoxide and soot. However, it is difficult to reduce the thermal NOx produced in the high temperature flame. To solve this problem, we developed externally oscillated oil burner which is possible for the high efficiency combustion and low NOx emission, simultaneously. The experiment of flame characteristics and NOx reduction were achieved according to the variation of frequency, amplitude and air velocity. Frequency, amplitude and air velocity are the most important parameter. The optimum operating conditions are frequency 1,900 Hz, amplitude 3 $V_{pp.}$ and air velocity 6.8 m/s. Reduction of NOx and CO are 47% and 22%, respectively.

Optimal Design of GaN-FET based High Efficiency and High Power Density Boundary Conduction Mode Active Clamp Flyback Converter (GaN-FET 기반의 고효율 및 고전력밀도 경계전류모드 능동 클램프 플라이백 컨버터 최적설계)

  • Lee, Chang-Min;Gu, Hyun-Su;Ji, Sang-Keun;Ryu, Dong-Kyun;Kang, Jeong-Il;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.4
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    • pp.259-267
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    • 2019
  • An active clamp flyback (ACF) converter applies a clamp circuit and circulates the energy of leakage inductance to the input side, thereby achieving a zero-voltage switching (ZVS) operation and greatly reducing switching losses. The switching losses are further reduced by applying a gallium nitride field effect transistor (GaN-FET) with excellent switching characteristics, and ZVS operation can be accomplished under light load with boundary conduction mode (BCM) operation. Optimal design is performed on the basis of loss analysis by selecting magnetization inductance based on BCM operation and a clamp capacitor for loss reduction. Therefore, the size of the reactive element can be reduced through high-frequency operation, and a high-efficiency and high-power-density converter can be achieved. This study proposes an optimal design for a high-efficiency and high-power-density BCM ACF converter based on GaN-FETs and verifies it through experimental results of a 65 W-rated prototype.

Developing a Cooling System for Fuel Cell Stacks Combined with Heat Pump Technology Using 1-D Simulation (1-D 시뮬레이션을 이용한 히트펌프 기술과 결합된 연료전지 스택용 냉각 시스템 개발)

  • Sang-Min Chung;Dong Gyu Park;Minsu Kim;Sung-wook Na;Seung-Jun Lee;Oh-Sung Kwon;Chul-Hee Lee
    • Journal of Drive and Control
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    • v.21 no.2
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    • pp.1-7
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    • 2024
  • This paper proposes a novel cooling system for hydrogen fuel cell cooling systems by integrating heat pump technology to enhance operational efficiency. The study analyzed the cooling efficiency of the fuel cell cooling system. With the increasing focus on eco-friendly vehicle technologies to address environmental concerns and global warming, the transportation sector, a major contributor to greenhouse gas emissions, needs technological enhancements for better efficiency. The proposed cooling system was modeled through 1-D simulations. The analysis results of parameters such as thermal balance, temperature, and pressure of each component confirmed the stable operation of the system. By examining variations in the cooling system's flow rate, compressor RPM, and the Coefficient of Performance (COP) based on different refrigerants, initial research was conducted to derive optimal operating conditions and parameter values.

Electroluminesent Properties of Phenothiazyl Derivatives Having Aromatic Moieties

  • Kim, Soo-Kang;Kang, In-Nam;Park, Jong-Wook;Kim, Kyoung-Soo;Choi, Cheol-Kyu;Lee, Sang-Do;Kim, Sang-Wook
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1054-1058
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    • 2006
  • We report the synthesis and electroluminescent properties of new aromatic compounds as hole-transporting materials based on phenothiazine, such as 1,4-diphenothiazyl-benzene [DPtzB], 1,4-diphenothiazyl-xylene [DPtzX] and 9,10-diphenothiazyl-anthracene [DPtzA]. DPtzB thin film exhibited photoluminescence (PL) maximum emission peak and emission shoulder at 450 and 475nm, and maximum emission at 447nm without emission shoulder was found in DPtzX thin film. When DPtzA was excited by incident light of 359nm, DPtzA showed strong PL emission at 417nm and weak emission at 600nm. Luminance efficiency of DPtzB, DPtzX and DPtzA-based electroluminescence (EL) devices was 3.57, 3.46 and 0.47cd/A, and power efficiency of DPtzB, DPtzX and DPtzA-based EL devices was 1.48, 1.26 and 0.20lm/W.

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Shape Optimization for Enhancing the Performance of an Inducer for the Main Hydraulic Pump in a Rotary Wing Aircraft (회전익 항공기 주유압펌프용 인듀서 성능 향상을 위한 형상최적설계)

  • Kim, Hyogyeum;Heo, Hyeungseok;Park, Youngil;Lee, Changdon
    • Journal of Drive and Control
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    • v.14 no.2
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    • pp.37-44
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    • 2017
  • In this study, in order to prevent cavitation in a variable swash-plate type hydraulic pump, a basic model impeller has been applied to a new pump, and the impeller shape has been optimized through flow analysis. Based on the analysis results, we could propose an impeller shape with high efficiency and low possibility of cavitation in comparison with the basic model. The simplification of the basic shape of the impeller of the hydraulic pump was performed in three parts in the order of hub shape, wing, and curvature, and eight design parameters were defined to satisfy the design requirement. Compared with the initial model of the impeller, when the differential pressure of the optimum model increased, the efficiency was improved. It achieved the goal of design improvement because cavitation did not occur under the rated operating conditions.

A Study of Low Temperature Combustion System Optimization for Heavy Duty Diesel Engine (대형디젤엔진의 저온연소 시스템 최적화에 관한 연구)

  • Han, Youngdeok;Shim, Euijoon;Shin, Seunghyup;Kim, Duksang
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.2
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    • pp.178-184
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    • 2015
  • According to the regulation on the environment and fuel efficiency is becoming strict, many experiments are conducted to improve efficiency and emission in internal combustion engines. LTC (Low temperature combustion) technology is a promised solution for low emissions but there are a few barriers for the commercial engine. This paper includes optimization that applies LTC method to heavy duty diesel engine. Adequate LTC was applied to low and middle load as adaptability in heavy duty diesel engine, and optimization focused on reduction of fuel consumption was proceeded at high load. Through this research, strategy for practical use of LTC was selected, and fuel consumption has improved on the condition that satisfies the emission regulation at systematic viewpoint.

A Novel Two-Mode MPPT Control Algorithm Based on Comparative Study of Existing Algorithms (새로운 MPPT 알고리듬의 시뮬레이션 및 실험을 통한 실증 연구)

  • Choi, J.Y.;Yu, G.J.;Jeong, Y.S.
    • Proceedings of the KIEE Conference
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    • 2002.04a
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    • pp.207-212
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    • 2002
  • As is well-known, the maximum power point(MPP) of PV power generation system depends on array temperature and solar insolation, it is necessary to track MPP of solar array all the time. Among various MPP control algorithms, the constant voltage control method, the perturbation and observation(P&O) method and the incremental conductance method(IncCond) have drawn many attractions due to the usefulness of each system. In this paper, the effectiveness of above mentioned three different control algorithms are thoroughly investigated via simulations and proposed efficiency evaluation method on experiment. Both the steady-state and transient characteristics of each control algorithms along with measured efficiency are analyzed, respectively. Finally, a novel MPPT control algorithm combining the constant voltage control and IncCond method for low insolation condition is proposed to improve efficiency of the 3KW PV power generation system.

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Post Sliced Cleaning of Silicon Wafers using Ozone and Ultrasound (오존과 초음파를 이용한 실리콘 웨이퍼의 Post Sliced Cleaning)

  • Choi, Eun-Suck;Bae, So-Ik
    • Korean Journal of Materials Research
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    • v.16 no.2
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    • pp.75-79
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    • 2006
  • The effect of ozone and/or ultrasound treatments on the efficiency of slurry removal in post sliced cleaning (PSC) of silicon ingot was studied. Efficiency of slurry removal was evaluated as functions of time, temperature and surfactant with DOE (Design of Experiment) method. Residual slurries were observed on the wafer surface in case of cleaning by ozone or ultrasound separately. However, a clean wafer surface was appeared when cleaned with ozone and ultrasound simultaneously. It has found that cleaning time was the main effect among temperature, time and surfactant. Elevated temperature, addition of surfactant and high ozone concentration helped to accelerate efficient removal of slurry. The improvement of removal efficiency seems to be related to the formation of more active OH radicals. The highly cleaned surface was achieved at 10 wt% ozone, 1 min and 10 vol% surfactant with ultrasound. Application of ozone and ultrasound might be a useful method for PSC process in wafer cleaning.

A Study of the High Efficiency Sea Water Cooling System for the Propulsion Diesel Engine of Warships (함정 추진디젤기관의 고효율 해수냉각시스템에 관한 연구)

  • Kang, Byoung-Soo;Lim, Young-Soo;Jo, Kwan-Jun
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.4
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    • pp.468-472
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    • 2015
  • Recently, there has been increasing interest in the efficient use of energy due to policies related to the reduction of greenhouse gas. This paper suggests a highly efficient sea water cooling system for the load-dependent control of a seawater pump depending on the load, to improve energy efficiency of the warship. This study models the propulsion diesel engine and simulation reflecting the characteristics of the warship operation state that checked the performance of high efficiency sea water cooling system. The simulation results revealed the cooling system of high efficiency with energy savings of approximately 53% compared to the existing cooling systems. These results can be used to improve the performance of the cooling system of the warship propulsion diesel engine in the future.