• 전기의세계
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• 제26권6호
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• pp.48-54
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• 1977

The object of this work is to study the optimal control strategy of constant speed characteristics for a D.C control motor under influence of disturbance. In the course of the analysis, the linearization and time invariance schemes on motor dynamics are presumed throughout under certain prescribed conditions and the performance measure for optimality is assumed to be quadratic in state and the control effort, with the initial and final time specified. When the motor speed is deviated from a stationary operating point by any external disturbance, the optimal continuous feedback control law is investigated by the application of the calculus of variation and realizability of the required control meachanism is suggested. Finally, the comparative study of the speed reasponses of the motor, with and without the optimal control effort is also presented to confirm the obtained results.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.311-326
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• 2005

The paper deals with the problem of selective harvesting in a prey-predator model with predator self limitation. Criteria for local stability and global stability for both the exploited and unexploited system are derived. The effort has been considered as a dynamic variable and taxation as a control instrument to protect the fish populations from over exploitation. Finally, the optimal taxation policy is discussed with the help of control theory.

• Journal of Preventive Medicine and Public Health
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• 제34권1호
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• pp.73-79
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• 2001

Objectives : To examine predictors of successful control for selfishness, dishonesty, resentment, and fear(SDRF) among Korean Alcoholics Anonymous(AA) members. Methods : This study was a cross-sectional study. The study group included members from 18 different AA groups which were enrolled in the Korean AA Association in 1998. 207 Out of 300 self administered questionnaires were completed by AA members (response rate 69.0%). Alcoholics who attended AA meetings were divided into two groups according to their self reported level of success in SDRF control; one with very successful experience after AA participation and the other with little or no success. In this study, the general characteristics, AA activities, relapse experience, and degree of effort exerted for SDRF control were compared between two groups. In order to study predictors of successful SDRF control after joining AA, 4 logistic regression analyses were performed for each of the 4 SDRF indices. Results : The proportion of those reporting a 'very successful' experience was 19.9% for selfishness, 20.7% for dishonesty, 25.5% for resentment, and 24.7% for fear. After control for the effect of general characteristics, the practice of the 12th step(taking alcoholics to an AA meeting after conveying messages) was found to be a significant predictor for the successful control of both selfishness(OR=6.04) and the dishonesty(OR=7.77). And individuals making every effort for SDRF control showed more successful control of selfishness(OR=4.10), dishonesty(OR=4.01, and fear(OR=34.89). Conclusions : Bivariate and multivariate analyses demonstrated that especially practicing the 12th step and making every effort themselves, may help alcoholics to control SDRF successfully after joining AA.

• KDI Journal of Economic Policy
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• 제27권2호
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• pp.205-237
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• 2005

본 논문은 기업의 주주가 경영자에게 경영을 대리하게 하여 본인-대리인관계(principal-agent relationship)가 발생하는 상황에서 상품시장경쟁이 기업의 내부효율성에 영향을 미치는 메커니즘을 분석한다. 본 논문에서는 두 종류의 기업을 고려한다. 하나는 기존기업(incumbents)이고, 다른 하나는 신규 진입기업(entrants)이다. 각 기존기업의 주주는 경영자에게 경영을 위임하고 경영자의 노력을 관찰하지 못하여 도덕적 해이가 발생한다. 기존기업의 경영자는 두 종류의 일을 수행하는데, 하나는 비용절감을 위한 노력(생산적인 노력)이고, 다른 하나는 진입장벽을 구축하기 위한 노력(비생산적인 노력)이다. 기존기업의 수로 측정되는 경쟁도의 증가는 두 가지 효과를 유발한다. 하나는 '산출효과'로서 경영자의 생산적인 노력을 감소시키고, 다른 하나는 '노력대체효과'로서 비생산적인 노력을 감소시키고 동시에 생산적인 노력을 유도한다. 본 논문은 어떠한 조건에서 시장경쟁이 생산적인 노력에 대한 유인을 제공하는 비용을 감소시켜 기업의 내부효율성을 증진하는가를 살펴본다.

• Asia Marketing Journal
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• 제22권1호
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• pp.27-39
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• 2020

Building on the growing literature on how physical bodily expressions influence psychological processes, the authors propose that exerting physical strength decreases risk perceptions and increases preference for risky options by increasing perceptions of control or agency. The present research is based on the belief of "no pain, no gain", that when an individual exerts physical strength and effort, he believes he can be the agent in bringing about the desired outcome. Because of this automatic association between exerting physical strength and the sense of being in control of the outcome, the authors hypothesize that even in situations where the outcome is determined by chance and luck, individuals exerting effort feel they have more control and thus choose riskier, but more desirable, options. Furthermore, this research clarifies the distinction between physical exertion of strength, high- and low-power poses, and psychological power.

• 전기의세계
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• 제21권3호
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• pp.31-40
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• 1972

This study intends to investigate the optimal switching modes of a double-capacitive thermal system under different constraints on the state and the control variable, by the application of the Pontryagin's Minimum Principle. Throughout the development, the control effort is assumed to have two modes of state: M or zero and the terminal times being fixed. In the first part of this study, the Principle is discussed under various conditions for this particular problem, with different criterion functions and in the same time imposing a certain constraints; i) on the terminal states, ii) on functions of the terminal states. Depending upon the upper bound value of the control vector, possible driving modes of the states are studied from which particular optimal driving modes are extracted so as to meet the specified constraints and boundary conditions imposed in the problem. Numerical solutions are evaluated for an over0damped, double-capacitive thermal plant and the optimal solutions: the switching mode, the optimal switching time, and the control effort are compared with the analytical results, in the second part of this work, to confirm the development.

• International Journal of Control, Automation, and Systems
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• 제2권4호
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• pp.450-462
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• 2004

In this paper, we describe a system for controlling the perceptual processes of two cooperative mobile robots that addresses the issue of enhancing perceptual awareness. We define awareness here as knowing the location of other robots in the environment. The proposed system benefits from a formalism called perceptual anchoring. Here, perceptual anchoring enhances the awareness of the system by employing an anchor-based active gaze control strategy or active perceptual anchoring to control the perceptual effort according to what is important at a given time. By anchoring we extend the notion of awareness as knowing what the symbols in the control module represent to by connecting them to the objects or features in the environment. We demonstrate the present system through a simulation of two nonholonomic mobile robots performing a cooperative transportation by carrying a cargo to a target location where there are two other robots moving about. The system is able to efficiently focus the perceptual effort and thus able to safely carry the cargo to the target position.

• 동아시아식생활학회지
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• 제16권6호
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• pp.646-654
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• 2006

This study was designed to examine body shape control and its related factors, including BMI(body mass index), desire for weight control, satisfaction with body shape, dissatisfaction with specific parts of body shape, starting period of concern about body shape, as well as experience, method, result, counsel, effort, expense and knowledge of body shape control. The survey was completed by 180 female university students in Gyeongsanbukdo through a self-administered questionnaire during September and October of 2006. The subjects were assigned to one of three groups based on self-estimated figure: 47.8% of the students estimated their figure as 'normal', while 38.3% of the students estimated themselves as 'thin' and 13.9% of the students as 'fat'. The results were as fellows. The mean age of the subjects was $19.45{\pm}1.67$ with a height and weight of $161.15{\pm}4.99cm$ and $52.63{\pm}10.78\;kg$, respectively. Their self-estimated figure was significantly related to BMI, desire for weight control, satisfaction, dissatisfaction with a specific part, and experience, counsel and effort in body shape control. This research suggests that students need to know how to properly control body shape in health and beauty.

• 한국인공지능학회지
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• 제3권1호
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• pp.4-6
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• 2015

These days, citizens have made change of food life to take Western style food and to suffer from diabetes because of excessive nutrition taking, less exercise, stress and other environmental factors. They may suffer from diabetes because of genetic defect, surgery of pancreas, disinfection and medicine and others. One of ten Koreans may have symptom of diabetes to be popular. The diabetes that is a kind of metabolic disease has high blood sugar at disorder of hyper insulinism and/or defect of insulin action. Long time high blood sugar may produce chronic disease of kidney, eyes, nerve, heart and blood vessel and others. The purpose of health care of diabetes patient was to reach target blood sugar by diet, physical exercise and medicine and to prevent and delay complication. Diabetes patient shall control blood sugar to keep healthy. The blood sugar control requires time and effort, and all of the patients are difficult to make effort and to spend time. You can control blood sugar by the application. The application allows patients to control blood sugar and to save time and efforts and to make small sized input and automation of remaining area. The service was limited to blood sugar graph, and user carries smart phone to conduct test and to have difficulty. Further study needs to solve the problems and to investigate blood sugar testing not carrying smart phone and to make application of easy control of blood sugar.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.813-818
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• 2005

In this paper, a re-adhesion control scheme is proposed for 1C2M propulsion system of TTX. The possibility of slip between wheel and rail in railway system is increasing because of the tendency of high speed and a climatic change. This slip results in the decrease of adhesive effort between this wheel and rail, so the control strategy of traction effort which can reduce the speed promptly and make most use of the maximum adhesive force is absolutely necessary. This paper describes the modeling of the TTX system, and this system is verified by the simulation.