• 설비공학논문집
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• 제8권1호
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• pp.76-87
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• 1996

Energy analysis for the hot water heating control system of apartment house complex is accomplished by computer simulation. Mathematical model of a boiler, pipe network and a unit-house is developed. The effects of heating control methods on the heating performance and energy consumption of the system are investigated. The heating control methods considered in this study are a continuous heating control, and on-off heating control and an intermittent heating control methods. For each control method, the effects of an outdoor temperature, indoor temperature sensing position and the capacities of the boilers and circulating pumps on the heating performance and energy consumption are obtained and "the best" control method is recommended.commended.

• Journal of applied mathematics & informatics
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• 제6권3호
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• pp.697-726
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• 1999

In this paper we develop a now procedure to control stepsize for linear multistep methods applied to semi-explicit index 1 differential-algebraic equations. in contrast to the standard approach the error control mechanism presented here is based on monitoring and contolling both the local and global errors of multistep formulas. As a result such methods with the local-global stepsize control solve differential-algebraic equation with any prescribed accuracy (up to round-off errors). For implicit multistep methods we give the minimum number of both full and modified Newton iterations allowing the iterative approxima-tions to be correctly used in the procedure of the local-global stepsize control. We also discuss validity of simple iterations for high accuracy solving differential-algebraic equations. Numerical tests support the the-oretical results of the paper.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.949-952
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• 1993

As well-known, fuzzy control has been recognized to be of great usefulness in many engineering fields. However, the present design methods of fuzzy control systems depend on trial and error the thing that limits its usefulness. Therefore, an effective and convenient support tools for design and evaluation are greatly needed as well as the establishment of the design methods and guidling. From these backgrounds, we have developed a fuzzy control simulator[1, 2] which has various fuzzy control methods such as "direct method", "indirect method" and "fuzzy-PID method". This paper deals especially with the "direct method" function of the simulator. The simulator was developed for personal computers and programed in C language.

• 제어로봇시스템학회지
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• 제2권1호
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• pp.59-71
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• 1996

In the last decade, the model predictive control methods have enjoyed many industrial applications with successful results. Although the general predictive control methods for nonlinear chemical processes are not yet formulated, the promising features of the model predictive control methods attract attentions of many researchers who are involved with difficult but important nonlinear process control problems. Recently, the class of bilinear model has been introduced as an useful tool for examining many nonlinear phenomena. Since their structural properties are similar to those of linear models, it is not difficult to develop a robust adaptive model predictive control method based on bilinear model. We expect that the model predictive control method based on bilinear model will expand its region in the world of nonlinear systems.

• Journal of Power Electronics
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• 제14권5호
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• pp.989-999
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• 2014

High-performance Current Source Inverter (CSI)-fed, variable speed alternating current drives are prepared for various industrial applications. CSI-fed Induction Motor (IM) drives are managed by using different control methods. Noteworthy methods include scalar Control (V/f), Input-Output Linearization (IOL) control, Field-Oriented Control (FOC), and Direct Torque Control (DTC). The objective of this work is to compare the dynamic performance of the aforementioned drive control methods for CSI-fed IM drives. The dynamic performance results of the proposed drives are individually analyzed through sensitivity tests. The tests selected for the comparison are step changes in the reference speed and torque of the motor drive. The operation and performance of different vector control methods are verified through simulations with MATLAB/Simulink and experimental results.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.767-775
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• 2003

This paper considers the method of elimination harmonics in AC/DC converters, There are few practical methods to reduce the harmonics in AC/DC converters, particularly in filter design and control strategy. In this paper, a harmonic elimination methods are proposed, which includes hybrid PWM control strategy. These methods achieve precise output control along with the optimum performance simultaneously. The control method in this paper is developed to eliminate a fixed number of harmonics in AC to DC converter. The higher order harmonics can be easily eliminated by using filter proposed in this paper. The validity of these methods is confirmed experimentally.

• 여성건강간호학회지
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• 제9권3호
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• pp.299-308
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• 2003

Purpose: This study was designed to identify nurses' perceptions and educational intentions regarding natural childbirth control (NCC) methods. Method: The participants were 313 nurses working at three general hospitals in Seoul. They were asked to complete a questionnaire composed of scales measuring knowledge and perceptions childbirth control methods, awareness of bodily changes in ovulation phase, perceptions of fetal life, which were developed by the author. Also, Chang's (2002) Sexual Autonomy Inventory was utilized. The data were analyzed by the SAS program. Results : Methods of condom and rhythm were considered to be more useful for childbirth control than other methods. Only 34-54% of them knew exactly about the NCC methods using menstrual cycle, body temperature, and mucus. The mean scores of sexual autonomy and awareness of bodily changes in ovulation phase were 3.8 and 3.4 out of 5, in respect. Educational intention was different statistically by the age, marital status, future intention to use NCC methods, and perception of educational need for NCC methods. Conclusion : Nurses' perceptions and educational intentions regarding NCC were low, especially in nurses who were married. It is recommended to encourage nurses to learn NCC methods for clients education.

• 제어로봇시스템학회논문지
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• 제20권3호
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• pp.298-312
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• 2014

This paper describes control applications in automobiles. Many aspects of automotive applications of advanced control methods, which include suspension systems, stability control systems, engines, hybrid vehicle control systems, electric vehicle controls systems, advanced driver assistance systems and automated driving control systems, are reviewed. The control methods used in each area are briefly reviewed to help readers understand the applicability and effectiveness of these methods. In addition, some new trends in the research of automotive applications are described.

• 설비공학논문집
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• 제13권11호
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• pp.1165-1173
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• 2001

The objectives of this study are to analyze the application of radiant floor cooling and to evaluate the control methods through experiments when the radiant heating system is used for cooling. Through the experiment analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The cooling curve (reset ratio) is found for radiant cooling, which shows tole relation between outside air temperature and supply water temperature. Comparison of cooling methods shows that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.103-129
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• 2019

The main goal of a case-control study is to learn the association between various risk factors and a primary outcome (e.g., disease status). Particularly recently, it is also quite common to perform secondary analyses of the case-control data in order to understand certain associations between the risk factors of the primary outcome. It has been repeatedly documented with case-control data, association studies of the risk factors that ignore the case-control sampling scheme can produce highly biased estimates of the population effects. In this article, we review the issues of the naive secondary analyses that do not account for the biased sampling scheme, and also the various methods that have been proposed to account for the case-control ascertainment. We additionally compare the results of many of the discussed methods in an example examining the association of a particular genetic variant with smoking behavior, where the data were obtained from a lung cancer case-control study.