• 한국정보과학회논문지:소프트웨어및응용
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• 제27권4호
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• pp.342-356
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• 2000

주어진 프로그램에서 예외상황(exception)을 발생시키는 테스트 데이타를 자동으로 생성해주는 분석 방법을 제안한다. 분석 결과로 얻은 테스트 데이타를 사용하여, 프로그램 내에서 발생한 예외상황들이 프로그래머의 의도대로 처리되는지를 검사할 수 있다. 본 논문에서 제안하는 분석 방법은 입력으로 받은 프로그램에서 특정 예외상황이 발생한다는 조건을 시작으로 하여, 프로그램의 입력 값에 대한 제약식(constraints)을 만들어간다. 이 분석 방법이 옳다는 증명에 의해서, 분석 결과로 얻은 테스트 데이타를 입력으로 하여 프로그램을 수행시키면 지정한 예외상황이 항상 발생한다는 것을 보장할 수 있다.함수를 인수나 결과값으로 전달하지 않고(first-order) ML 스타일의 예외상황 관리 방법을 제공하는 언어를 대상으로 하여 테스트 데이타 생성 방법을 제안하고, 이 분석 방법이 옳다는 것을 증명한 후 몇 가지 예를 사용하여 분석 과정을 설명한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.678-680
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• 1998

Based on fuzzy logic algorithm this paper constructed fuzzy logic controller for automated vehicles. For passenger's convenience especially comfortability controller need to reduce the frequency of input variable's changing. So we established membership functions for comfortability as mil as speed following. It made possible to control comfortability directly. To demonstration the efficiency of fuzzy logic controller, we carried out simulation with a Automobile's transfer function. First, we designed the PID controller by using Ziegler-Nichols tunning method. Second, we calculated time response for each controller, then we compared the speed patterns of fuzzy controlled system and PID controlled system. Also we compared the difference of input variable. By comparing two controller's response, we can confirm the merit of fuzzy controller about comfortability. Fuzzy controller can reduce input changing frequency.

• 한국기계가공학회지
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• 제15권2호
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• pp.131-138
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• 2016

In order to improve the performance of an extended Kalman filter, a simplified indirect inference method (SIIM) fuzzy logic system (FLS) is proposed. The proposed FLS is composed of two fuzzy input variables, four fuzzy rules and one fuzzy output. Two normalized fuzzy input variables are the variance between the trace of a prior and a posterior covariance matrix, and the residual error of a Kalman algorithm. One fuzzy output variable is the weighting factor to adjust for the Kalman gain. There is no need to decide the number and the membership function of input variables, because we employ the normalized monotone increasing/decreasing function. The single parameter to be determined is the magnitude of a universe of discourse in the output variable. The structure of the proposed FLS is simple and easy to apply to various nonlinear state estimation problems. The simulation results show that the proposed FLS has strong adaptability to estimate the states of the incoming/outgoing moving objects, and outperforms the conventional extended Kalman filter algorithm by providing solutions that are more accurate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.531-534
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• 1989

In this paper, the way that input voltage and input line current as a control variable is provided as one unit is projected. Till no, have denied with three phase balanced load. But, in that case, total power factor compensation is difficult, for to control each phase at unbalanced load. Therefor, in this paper suggest of the scheme that three phase unbalanced load is controlled by each phase and input total power factor is compensated unit input factor. therefore, in this paper suggest that three phase unbalanced load is controlled and the method in compensation of unit input factor to be attended by unbalanced load. Besides, the object of control is calculating quantity for input voltage and input line current for the point at issuse make to improve of control method at unbalanced load. As a result, control system of each phase could maintain as a unit input total power factor has been state diviation error of 2% with unbalanced load.

• 대한안전경영과학회지
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• 제26권2호
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• pp.107-115
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• 2024

This study conducted frequency analysis, reliability analysis, descriptive statistics, and correlation analysis to determine the impact of quality control managers' perception and implementation of KS certification factory inspection evaluation items on follow-up management. Through a multiple linear regression model, the influence of KS certification officer's awareness and implementation of KS certification factory inspection on post management was found to have a positive (+) influence on post management, with implementation having a greater influence on post management than awareness. It was having an impact. The independent variable (perception) has a statistically significant impact on the mediating variable (execution), and in the stage of verifying the mediating effect, the influence of the independent variable (perception) on the dependent variable (follow-up management) has a statistically significant impact. , In the stage where the independent variable (perception) and the mediator (implementation) are input simultaneously, both the independent variable and the mediator have a statistically significant effect on the dependent variable, indicating that there is a mediation effect.

• 한국지능시스템학회논문지
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• 제15권1호
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• pp.24-29
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• 2005

일반적으로 다변수 계통에 대한 퍼지 제어에서 퍼지 규칙을 얻기가 어려워 입출력 사이의 페어링을 이용한 독립적인 단일 입력 단일 출력의 병렬 구조를 이용한다. 그러나, 결합되지 않은 입출력 변수간의 상호작용으로 제어 성능에 나쁜 영향을 준다. 특히, 강한 결합 특성을 가진 계통의 경우 제어 성능을 아주 저하시킨다. 본 논문에서는 이러한 상호작용에 의한 영향을 보상해주기 위해 상대 이득 행렬을 이용한 신경 회로망을 도입하였다 제안한 뉴로 퍼지 제어기는 역전파 알고리즘으로 학습되며 강호작용에 대한 결합강도를 자동으로 조정하여준다. 제안한 뉴로 퍼지 제어기의 성능을 200MW급 보일러 계통에 대한 컴퓨터 모의실험을 통해 입증하였다.

• 설비공학논문집
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• 제26권12호
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• pp.579-587
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• 2014

This paper deals with precise analytical state equation modeling of a variable speed refrigeration system (VSRS) for optimum control in state space. The VSRS is described as multi-input and multi-output (MIMO) system, which has two controlled variables and two control inputs. First, the Navier-Stokes equation and mass flow rate were applied to each component of the basic refrigeration cycle to build a dynamic model. The dynamic model, represented by a differential equation, was transformed into the state equation formula. Next, a full-order state observer was built to estimate all of the state variables to compose an optimum control system. Then, an optimum controller was designed to minimize an evaluation function that has input energy and control error. Finally, simulations and experiments were conducted to verify the validity of the proposed modeling and designed optimum controller to regulate target temperature and superheat in a 1RT oil cooler system. The results show that the proposed method, state equation modeling and optimum control, is efficient to ensure optimal control performance of the VSRS.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.936-941
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• 2004

An Optimal Feedforward Integral Variable Structure or FIVSC approach for an electrohydraulic position servo control system is presented in this paper. The FIVSC algorithm combines feedforward strategy and integral in the conventional Variable Structure Control (VSC) and calculating the control function to guarantee the existence of a sliding mode. Furthermore, the chattering in the control signal is suppressed by replacing the sign function in the control function with a smoothing function. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances when compared with some existing control methods, like the IVSC and MIVSC strategies. Simulation results illustrate that the purposed approach can achieve a zero steady state error for ramp input and has an optimal motion with respect to a quadratic performance index. Moreover, Its can achieve accurate servo tracking in the presence of plant parameter variation and external load disturbances.

• Journal of electromagnetic engineering and science
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• 제16권4호
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• pp.206-209
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• 2016

This letter proposes a reconfigurable directional coupler that uses a variable impedance mismatch reflector to achieve high isolation characteristics in the antenna front end. The reconfigurable coupler consists of a directional coupler and a single-pole four-throw (SP4T) switch with different load impedances as a variable load mismatch reflector. Selection of the load impedance by the reflector allows cancellation of the reflected signal due to antenna load mismatch and the leakage from the input to isolation port of the directional coupler, resulting in high isolation characteristics. The performance of the proposed architecture in separating the received (Rx) signal from the transmitted (Tx) signal in the antenna front end was verified by implementing and testing the reconfigurable coupler at 917 MHz for UHF radio-frequency identification (RFID) applications. The proposed reconfigurable directional coupler showed an improvement in the isolation characteristics of more than 20 dB at the operation frequency band.

• 전기학회논문지
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• 제59권6호
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• pp.1173-1178
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• 2010

In this note, a systematic design of a new robust nonlinear integral variable structure controller based on state dependent nonlinear form is presented for the control of uncertain more affine nonlinear systems with mismatched uncertainties and matched disturbance. After an affine uncertain nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a new robust nonlinear integral variable structure controller is presented. To be linear in the closed loop resultant dynamics and remove the reaching phase problems, the linear integral sliding surface is suggested. A corresponding control input is proposed to satisfy the closed loop exponential stability and the existence condition of the sliding mode on the linear integral sliding surface, which will be investigated in Theorem 1. Through a design example and simulation studies, the usefulness of the proposed controller is verified.