• Title/Summary/Keyword: self-starting

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The Influence of North Korean Refugees' Individual Characteristics and Entrepreneurial Motives on Entrepreneurial Intention (북한이탈주민의 창업 개인특성과 창업동기가 창업의지에 미치는 영향)

  • Park, Nam Tae;Lee, Bo Young
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.11 no.5
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    • pp.67-75
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    • 2016
  • The financial difficulties which North Korean refugees encounter during the process of transition into South Korean society is due to their low income and insufficient expertise. Hence this research was conducted for the purpose of improving the policy and system to support North Korean refugees' starting of businesses. As a result, the self-efficacy, which is one of the individual characteristics, influences the motivation for starting business. In addition, it has been revealed that the motives and education on starting business also influence the motivation for starting business. By observing regulation effect of social adaptation, it has been found out that the interaction between the personal characteristics such as risk-taking attribute and the previous experience of starting business, along with interaction effect on social adaptation and motives and social adaptation, is statically influencing as well. On the basis of results, to efficiently support North Korean refugees' starting business, it is necessary to conduct education on starting business to boost their self-efficacy and the support must be executed based on their levels of motives, risk-taking attribute and social adaptation.

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Flow-driven rotor simulation of vertical axis tidal turbines: A comparison of helical and straight blades

  • Le, Tuyen Quang;Lee, Kwang-Soo;Park, Jin-Soon;Ko, Jin Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.2
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    • pp.257-268
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    • 2014
  • In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

Analysis and Improvement for Single 6/6 SRM with a Saturable Area (자기 포화 영역을 갖는 단상 6/6 SRM의 자기 구조 해석 및 개선)

  • Oh, Seok-Gyu
    • Journal of the Korean Magnetics Society
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    • v.27 no.2
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    • pp.70-75
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    • 2017
  • Single-phase SRM is cost competitive because it can reduce the number of switches for small, low-cost applications. However, since the single-phase SRM is difficult to start itself, methods for realizing self-starting by using auxiliary magnet or auxiliary pole have been studied. Recently, a method of self-starting by changing the shape of the rotor with a saturable area has been proposed. The purpose of this paper is to analyze the magnetic structure of single phase 6/6 SRM with a saturable rotor and to improve the magnetic structure of rotor with a saturable area. For this magnetic analysis, FLUX2D, a finite element method analysis program, was used.

Detent Torque of Parking Magnet Starting Device Installed in the Single-Phase Switched Reluctance Motor (단상 스위치드 릴럭턴스 모터에 설치된 영구자석 기동장치의 디텐트 토크)

  • Kim, Jun-Ho;Lee, Seung-Min
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.5
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    • pp.408-412
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    • 2010
  • The single-phase switched reluctance motor(SRM) generates the positive torque in the restricted section. So, it can not started by itself and the torque ripple is heavier than poly-phase. For self-starting and fixing rotating direction, the rotor should be placed at the rising inductance slope when stationary. The parking permanent magnet locates the rotor in the fixed position, which can be started by it-self. It is very simple and cost effective but has some drawbacks. It affects the rotor during the operation, so the characteristics of motor, such as a torque, speed, and ripple are changed to go bad. This paper presents the detent torque of parking magnet starting device through the finite element analysis and experiments. The finite element analysis is performed at incremental rotor positions over one detent torque cycle for any one pole. The prototype, fabricated in the previous research, is used for the experiments. The inductance, instant torque, and detent torque are calculated using the terminal voltage and phase current. Finally, the finite element analysis result and the experiment result are compared for analysis and validity.

Excessive Condition Interpretation of a Exciter Circuit to Prevent Starting Failure of Large Synchronous Motor (대형 동기 전동기 기동실패방지를 위한 여자기회로 과도현상 해석)

  • Park, Jin-Hun;Cho, Ne-Su;Kwon, Woo-Hyen;Im, Soung-Hun;Yoon, Kyoung-Seop;Kim, Woo-Hyen
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.739-740
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    • 2006
  • According to the rapid growth of high speed and precise industry, the application of synchronous motor has been increased. In the application fields, the large synchronous motor is not a self-starting motor. The rotor is heavy and, from a dead stop, it is impossible to bring the rotor into magnetic lock with the rotating magnetic field for this reason, all synchronous motor have some kinds of starting device. A simple starter is another motor which brings the rotor up to approximately 96 percent of it synchronous speed. The starting motor is disconnected and the rotor locks in step with the rotating field. The more commony used starting method is to have the rotor to include a squirrel cage indution winding. This indution winding brings the rotor almost to synchronous speed as an induction motor. So, this paper describes excessive condition interpretation of a exciter circuit to prevent starting failure of large synchronous motor. the large synchronous motor needs safety of it in accordance with operating frequent start and stop. the operating Problem point of synchronous motor appears potential element damage of Exciter circuit because synchronous motor is caused synchronous separation. hence we eliminate it and improve starting toque.

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Preparation of Silicon Carbide Ceramics with Self-reinforced Microstructure by the Control of Starting Phases (출발상 제어에 의한 자기복합화 미세구조의 탄화규소 세라믹스 제조)

  • Lee, Jong-Kook;Kang, Hyun-Hee;Lee, Eun-Gu;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.34 no.12
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    • pp.1240-1246
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    • 1997
  • Silicon carbides with self-reinforced microstructure which hore a small grain matrix and dispersed large grains with rod-like type were prepared by the liquid-phase sintering and the control of starting phases of raw materials. The specimens with self-reinforced microstructure could be obtained from the compacts with mixed compositions of $\alpha$-SiC and 10-50 % $\beta$-SiC powders and by the pressureless sintering at 185$0^{\circ}C$ for 5h. Large grains with rod or plate-like types were 4H-SiC and small grains with equi-axed type were 6H-SiC. Fracture grains with rod or plate-like types were 4h-SiC and small grains with equi-axed type were 6H-SiC. Fracture toughness of specimens with self-reinforced microstructure was increased by the crack deflection and formation of microcracking due to the existence of rod-like large grains during crack propagation.

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A Study on the Main Winding Control of Single Phase Induction Motor using One-Chip Micom (원칩 마이컴을 이용한 단상유도전동기의 주권선 제어에 관한 연구)

  • Park, Su-Gang;Baek, Hyeong-Rae
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.1
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    • pp.70-76
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    • 2000
  • This paper describes a one-chip micom controller and phase angle control method for self-starting and energy saving of single-phase induction motor. The proposed method is based on the optimal efficiency control which is running by variable phase angle of main winding current such as to maintain the maximum efficiency characteristics of the motor, in voltage control with TRIAC. Experiments are focused on a capacitor starting single-phase induction motor. The optimal energy saving by variable phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

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Instant Torque of Salient Pole Rotor Type Single-Phase SRM According to Installed Permanent Magnet Starting Device or Not (영구자석 기동장치의 유무에 따른 회전자 돌극형 단상 SRM의 순간 토오크)

  • Kim Jun-Ho;Lee Eun-Woong;Lee Jong-Han;Kim Yong-Hun;Lee Hyun-Woo;Lee Min-Myung
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.959-961
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    • 2004
  • A multi pole SRM(switched reluctance motor) is applied by the regulated current in regular sequence. So, it can be started by itself. But a single phase SRM can not be started by itself because the positive torque is only generated in the limited zone which the inductance is increased. Therefore, it is required auxiliary device for self starting which place the rotor in start position. The prototype was designed and fabricated in the previous research. It has the permanent magnet, which is installed in the bottom of the rotor, for self starting. But the permanent magnet affect the prototype during operation and cause the decrease of the torque and speed. The influence of the permanent magnet on the average torque and speed was already confirmed. On this paper, the instant torque of the prototype was calculated from the experiment results which is the inductance and current according to installed permanent magnet or not.

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The Determinants of Economic and Educational Supports Selection of Small Self-employed Business (소규모자영업의 경제적$\cdot$교육적 지원 선택의 영향요인)

  • Hong Sung-Hee
    • Journal of Family Resource Management and Policy Review
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    • v.9 no.2
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    • pp.1-21
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    • 2005
  • The purpose of this study was to analyze the effect of the influencing factors on the economic and educational supports selection of small self-employed business. A sample of 321 was selected from self-employed workers living in Daegu. For data analysis, logistic regression was used. The major findings were as follows: 1 The determinants of the economic supports selection in self-employed business were father's working experiences in self-employed business, taking employees or not in business, having housing ownership or not, and as well as the amount of starting capital. 2. The determinants of the educational supports selection in self-employed business were self-employer's working experience as self-employed before or not, and empowerment with self-employed work.

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Analysis on Psychological Self-regulation and Arousal Variation of Actors on Performance (공연 시 배우의 각성변화와 심리적 자기조절 분석)

  • Hong, Kil-Dong;Lee, Hong-Sik;Lee, Hyung-Kook;Oh, Jin-Ho;Lee, Ki-Ho
    • The Journal of the Korea Contents Association
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    • v.8 no.12
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    • pp.176-189
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    • 2008
  • The purpose of this study was to analyze self-regulation about changing heart rate and perceived arousal variation when actors start their performance. Object of this study were 5 actors who belong to the theater selected using the purposive sampling method. This study used a measuring instrument of heart rate to measure arousal status, used behavior observation paper to observe and record self-regulation behavior and executed personal consultation after ending performance. There was graph mad by variation transition which calculated average and standard deviation about variation of heart rate each time of performance. The results of this study were as follows. First, there were high variation of awake level that actor's heart rates were rising before starting performance and the most high level of arousal was from 20minutes to 5minutes before starting performance. Second, there were self-regulation behaviors appeared such as deep breathing, breath controling, self talking, talking with other actors, concentrating an script, going to toilet, smoking, checking closes before starting performance. Third, when performance start, actors used psychological self-regulational method such as relaxation, self concentration, confidence reinforcement, coping with state or accommodation for controling raised arousal status.