• 수산해양기술연구
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• 제28권1호
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• pp.39-44
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• 1992

Analog PID controllers have been designed to make good use of position control in industries. Recently, the importance of digital position control is emphasized for the requirements of controller which are not only to control the objects but to include various aspects such as easiness of design and implementation, simple exchange of control program and convenient communications of data between various controllers and a host computer. This study proposes a combined control method which is mixed the vaiable structure control (VSC) with the PI control for minimum time position control of DC servo motor by microcomputer. The results of test by this method show offset-free and minimum time optimal position control which is not affected by the disturbance and the system parameter variations. The validity of the proposed method comparing with the conventional PID control is proved by the response experiments.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.136-147
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• 1998

An experimental facility consisting of two 3$\times$4.4$\times$2.8m rooms identical in construction is built. Each room has a control system and storage tank supplying hot water to the radiant floor heating system. The facility enables simultaneous comparison of two different control strategies each implemented in a separate room. The operating performance of three kinds of flow control scheme is tested and compared in this study: (ⅰ) conventional on-off control based on feedback from room air temperature (ⅱ) TPSC(two parameter switching control )(ⅲ) TPOC(two parameter on-off control). Results show that TPSC and TPOC using room air and surface temperature sequentially as feedback signal to control hot water supply is the better temperature regulation scheme than conventional control based on feedback from only room air temperature. They are good candidates for the room with radiant floor heating system under continuous and intermittent heating mode.

• 대한전기학회논문지
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• 제43권4호
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• pp.627-637
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• 1994

In this study, a predictive fuzzy control algorithm to supervise the elevator system with plural cars is developed and its performance is evaluated. The proposed algorithm is based on fuzzy in-ference system to cope with multiple control objects and uncertainty of system state. The control objects are represented as linguistic predictive fuzzy rules and simplified reasoning method is utilized as a fuzzy inference method. Real-time simulation is performed with respect o all possible modes of control, and the resultant controls ard predicted. The predicted rusults are then utilized as the control in-puts of the fuzzy rules. The feasibility of the proposed control algorithm is evaluated by graphic simulator on computer. Finallu, the results of graphic simulation is compared with those of a conventional group control algorighm.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.399-404
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• 2008

Condensing gas boiler units may make a big role for the reduction of energy consumption in heating industries. In order to decrease the energy consumption of a condensing gas boiler unit, the effective control of the system is necessary. In this study, control algorithms of a condensing gas boiler were developed. Control algorithms are composed of the setpoint algorithm and the control algorithm. The setpoint algorithm consists of the supply water temperature setpoint algorithm and the pump setpoint algorithm. The control algorithm consists of the gas valve control algorithm and the blower control algorithm. In order to analyse the performance of control algorithms, dynamic models of a condensing gas boiler system were used. Simulation results showed that control algorithms developed for this study may be practically applied to the condensing gas boiler.

• 설비공학논문집
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• 제13권12호
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• pp.1297-1305
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• 2001

In this study, existing control methods that are suggested or applied until now are classified by control parameters, and stability of in the room and floor surface temperatures of each control method is compared through experiments. Then, the control performance of these control methods are analyzed to evaluate the applicability to Korean apartment housing. From the result of the applicability analysis, the outdoor reset with on/off PWM control is found to be desirable for district heating systems and flux modulation is found to be applicable for decentralized heating systems. In the case of independent control systems for each room, on/off PWM control is desirable.

• 동력기계공학회지
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• 제10권1호
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• pp.90-95
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• 2006

Pneumatic control systems have been mainly used as a high speed operating system. Therefore, state change of air in a control volume was assumed to be adiabatic change and, pneumatic control systems have been analyzed by using this assumption. Especially, when absolute value of pressure change in the control volume is small, there is a tendency to neglect effect of temperature change on pneumatic control system because temperature change owing to pressure change is small. In this study, an effect of temperature change of air on the decompression control process was analyzed by considering change of mass flow rate, and heat transfer characteristics between air in the chamber and the chamber wall. As a result, this study could confirm that a slight temperature change of the air in the pneumatic pressure control system can influence on the dynamic characteristics of pressure response, and pressure control performance.

• 한국IT서비스학회:학술대회논문집
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• 한국IT서비스학회 2003년도 추계학술대회
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• pp.167-174
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• 2003

BPO(Business Process Outsourcing) is defined as outsourcing the management and operation of the IT intensive business process to another company that has specialty in managing the process. In the outsourcing arrangement, the design of the effective control mechanisms is essential to the success of the outsourcing. The purpose of this study is to investigate the effective control mechanisms between two organizations in a BPO arrangement. The specific research questions put forth are as follows: (1)What are the control issues in relation to BPO? (2)How the control mechanisms in the successful BPO arrangement are designed? and (3)What kind of effect or change do the designed control mechanisms have on the buyer's job process in terms of BPO? The results of this study found that the following mechanisms are effected in BPO setting: (1)Automation (2)Standardization & Modularity (3)Embedding (4)Balanced control (5)control segmentation (6)hierarchy (7)output/behavior control 8)back-end control 9)informal control.

• 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.

• 대한기계학회논문집A
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• 제21권8호
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• pp.1229-1240
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• 1997

The purpose of this study is to build up control scheme that promptly control pressure in a hydraulic cylinder having comparatively small control volume, using a PCV (proportional control valve) and a digital computer. Object pressure control system has the character to be unstable easily, because the displacement-flow gain of the PCV is too large considering the small volume of the hydraulic cylinder and the time delay of response of the PCV is comparatively long. Considering the above-mentioned characteristics of the object pressure control system, in this study, control system is designed with two degree of freedom control scheme that is composed by adding a feed-forward control path to I-PDD$^{2}$ control system, and a reference model is used on the decision of control parameters. And through some experiments on the control system with FF-I-PDD$^{2}$ controller, the validity of this control method has been confirmed.

• 수산해양교육연구
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• 제11권1호
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• pp.1-23
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• 1999

The fisheries control system being now enforced in all countries may be generally classified as three types - the input control system, the output control system, and the technical control system. In Asian countries that have relatively small fishery scales, diverse object species and the fisheries resources has been regarded as "governmental possessions", fisheries have been controled subsidiarily using the technical control system based on the input control system traditionally. While in Europe and America that have relatively large fisheries scales, simple object species and the fisheries resources has been regarded as "common property", fisheries have been controled subsidiarily using the input control system and the technical control system based on the output control system. In Korea, fisheries have been controled subsidiarily using the technical control system based on the input control system traditionally, nevertheless overexplotation and overcapitalization have not been solved. Recently the EEZ was promulgated, the total allowable catch system was introduced to control the EEZ. But the output control system is totally different from the input control system of the Korea traditional fisheries system, simultaneous availableness of both system is considerably difficulty. Therefore a study on new systems to make both systems harmonized has to be performed. The thesis is aimed at presenting the general improvement direction of the Korea fisheries control system as the basis for establishment of the new fisheries control system.