• Journal of applied mathematics & informatics
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• 제23권1_2호
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• pp.101-112
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• 2007

In this paper, by using fractional power of operators and Sadovskii fixed point theorem, we study the controllability of abstract neutral functional integrodifferential systems with infinite delay. As application, an example is provided to illustrate the obtained results.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제15권3호
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• pp.245-257
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• 2008

In this paper, we find the sufficient conditions of controllability of semi-linear neutral functional differential evolution equations with non local conditions using by fractional power of operators and Sadovskii's fixed point theorem.

• 한국사회복지학
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• 제66권2호
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• pp.255-286
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• 2014

본 연구는 학교 내 청소년들의 권력관계 유형 파악을 위해 사용할 수 있는 척도인 '권력장악가능성'과 '권력장악욕구' 척도의 개발 및 타당화를 목적으로 했다. 선행연구에서 사용되었던 문항들을 기초로 추가 문항을 개발하기 위해 초 중 고등학생들을 대상으로 개별 면접과 초점 집단 면접을 실시하였으며 개발된 문항의 안면타당도와 내용타당도 확인을 위해 학교교사 및 전문가 집단의 자문을 받았다. 최종 선정된 문항을 갖고 수도권 소재 초 중 고생(N=1,822)을 대상으로 설문을 실시해 탐색적 요인분석 및 확인적 요인분석을 수행하였다. 확인된 요인구조의 타당화를 위해 별도로 수집된 수도권 중학생 표본(N=333)을 대상으로 타당화 검사를 실시하였다. 타당화 표본을 통해 척도의 구성타당도와 신뢰도를 산출하였으며 '권력장악가능성'과 '권력장악욕구'를 바탕으로 분류된 권력관계 유형과 학교폭력 현장에서 학생들의 실제 역할 사이의 관련성을 확인함으로써 개발된 척도의 예측타당도를 점검하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.638-640
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• 2004

The gas stripper system of a nuclear power plant provides gas-free water to a reactor and a turbine system. The gas tripper unit has two control systems to regulate pressure and level independently. Because the level and the pressure interact as a control disturbance each other, continuous operation of the system is difficult. In this paper, We describe the controllability evaluation of the gas stripper system and the results of the optimally tuned control gains.

• 전자공학회논문지
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• 제50권7호
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• pp.244-252
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• 2013

본 논문에서는 이산사건시스템의 관리제어이론을 정치경제학에서 권력의 문제를 해석하는데 응용할 수 있음을 보인다. 이를 위해 권력에 기초한 제어입력의 결정 메커니즘과 이를 통한 관리제어시스템의 동작을 정의한다. 구체적으로, 경쟁하는 집단들(제어기들)의 공통 제어목적을 달성하기 위한 필요 충분 조건으로 권력-제어가능성의 개념을 소개한다. 이 조건이 만족되면 정해진 권력함수를 가진 집단들의 모듈러 제어를 통해 제어된 시스템은 공통의 제어목적을 벗어나지 않는다.

• 대한기계학회논문집A
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• 제23권6호
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• pp.1055-1064
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• 1999

In this wort ER(electro-rheological) clutch and MR(magneto-rheological) clutch are devised and their performance characteristics such as response time and controllability are compared. As a first step, field-dependent yield stresses of ER and MR fluids are distilled in shear mode. For reasonable comparison between two clutches, a nondimensional design model is established by choosing same design parameters of gap size and number. Following the manufacturing of two clutches, field-dependent torque level, response time to step input, mechanical Power generation to electric power consumption are experimentally measured and compared. In addition, in order to investigate torque controllability of the clutches a sliding mode controller is formulated and experimentally realized. Control bandwidths of two clutches are identified and tracking control responses for desired torque trajectories are presented.

• Asia pacific journal of information systems
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• 제18권2호
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• pp.1-14
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• 2008

According to technology acceptance model(TAN) which is one of the most important research models for explaining IT users' behavior, on intention of using IT is determined by usefulness and ease of use of it. However, TAM wouldn't explain the performance of using IT while it has been considered as a very good model for prediction of the intention. Many people would not be confirmed in the performance of using IT until they can control it at their will, although they think it useful and easy to use. In other words, in addition to usefulness and ease of use as in TAM, controllability is also should be a factor to determine acceptance of IT. Especially, there is a very close relationship between controllability and ease of use, both of which explain the other sides of control over the performance of using IT, so called perceived behavioral control(PBC) in social psychology. The objective of this study is to identify the relationship between ease of use and controllability, and analyse the effects of both two beliefs over performance and intention in using IT. For this purpose, we review the issues related with PBC in information systems studies as well as social psychology, Based on a review of PBC, we suggest a research model which includes the relationship between control and performance in using IT, and prove its validity empirically. Since it was introduced as qa variable for explaining volitional control for actions in theory of planned behavior(TPB), there have been confusion about concept of PBC in spite of its important role in predicting so many kinds of actions. Some studies define PBC as self-efficacy that means actor's perception of difficulty or ease of actions, while others as controllability. However, this confusion dose not imply conceptual contradiction but a double-faced feature of PBC since the performance of actions is related with both self-efficacy and controllability. In other words, these two concepts are discriminated and correlated with each other. Therefore, PBC should be considered as a composite concept consisting of self-efficacy and controllability, Use of IT has been also one of important areas for predictions by PBC. Most of them have been studied by analysis of comparison in prediction power between TAM and TPB or modification of TAM by inclusion of PBC as another belief as like usefulness and ease of use. Interestingly, unlike the other applications in social psychology, it is hard to find such confusion in the concept of PBC in the studies for use of IT. In most of studies, controllability is adapted as PBC since the concept of self-efficacy is included in ease of use explicitly. Based on these discussions, we can suggest perceived use control(PUC) which is defined as perception of control over the performance of using IT and composed of controllability and ease of use as sub-concepts. We suggest a research model explaining acceptance of IT which includes the relationships of PUC with attitude and performance of using IT. For empirical test of our research model, two user groups are selected for surveying questionnaires. In the first group, there are freshmen who take a basic course for Microsoft Excel, and the second group consists of senior students who take a course for analysis of management information by Excel. Most of measurements are adapted ones that have been validated in the other studies, while performance is real score of mid-term in each class. In result, four hypotheses related with PUC are supported statistically with very low significance level. Main contribution of this study is suggestion of PUC through theoretical review of PBC. Specifically, a hierarchical model of PUC are derived from very rigorous studies in the relationship between self-efficacy and controllability with a view of PBC in social psychology. The relationship between PUC and performance is another main contribution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.715-717
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• 1999

In this study, an intelligent solenoid valve controller has been developed for automatic maintaining of filters in a dust collecting system. This controller has automatic controllability of solenoid valves' ON/OFF time depending on the clogging status of filters, and then it can extend the filters' lifetimes, decrease the power consumption, and make effective operation of the system possible. This controllability has been executed by the fuzzy theory that utilizes the workers' experimental knowledges, the control expert's knowledges and the differential pressures between the inlets and outlets measured by the sensors.

• 전기학회논문지P
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• 제53권2호
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• pp.82-88
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• 2004

In this study, an intelligent solenoid valve controller has been developed for efficient maintaining of filters in a dust collecting system. This controller has automatic controllability of solenoid valves' ON/OFF time depending on the clogging status of filters, and then it can extend the filters' lifetimes, decrease the power consumption, and make effective operation of the system possible. This controllability has been executed by the fuzzy theory that utilizes the workers' experimental knowledges, the control expert's knowledges and the differential pressures between the inlets and outlets measured by the sensors. The system's operation is under the continuous surveillance by using a current transformer, which warns the operators and lets them take necessary actions in case of abnormal operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1333-1335
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• 2005

STATCOM has many advantages rather tan SVC at a view point of a continuous controllability of reactive power and response time of reactive power compensation In this paper, 30kVA STATCOM for compensation of low voltage industrial loads is designed and its operation characteristics is analyzed and verified by simulation.