• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1251-1258
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• 1999

The water level control of a steam generator in the unclear power plant is an important process. Most of the water level controllers of the actual plant are PID controllers. But they have limitations in appling for tracking the set point and getting rid of disturbances, so there are some defects to apply in the actual ground even though many research works represented the resolutions to solve it. In this paper, it is suggested that the established simple PID controller in low power has the ability to remove disturbances and trace the set-point, and then possesses the real-time self-tuning function according to the variety of moving peculiarity of a plant. This function realized by making use of fuzzy logic. PID parameters are formulated by a variable ${\alpha}$ and made it fluctuate by a fuzzy inference according to level error and level error change. This mechanism makes application of actual plant effective as well as taking advantage of improving the efficiency of water level controller by way of adding the function of self-tuning instead of replacing PID controller. The computer simulation of this scheme shows the improved performance compare to conventional PID controller.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• 조명전기설비학회논문지
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• 제23권11호
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• pp.9-21
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• 2009

This paper proposes the alternative observer and controller design scheme based on T-S fuzzy model. Nonlinear systems are represented by fuzzy models since fuzzy logic systems are universal approximators. In order to estimate the unmeasurable states of a given unknown nonlinear system, T-S fuzzy modeling method is applied to get the dynamics of an observation system. T-S fuzzy system uses the linear combination of the input state variables and the modeling applications of them to various kinds of nonlinear systems can be found. The proposed indirect adaptive fuzzy observer based on T-S fuzzy model can cope with not only unknown states but also unknown parameters. The proposed controller is based on a simple output feedback method. Therefore, it solves the singularity problem, without any additional algorithm, which occurs in the inverse dynamics based on the feedback linearization method. The adaptive fuzzy scheme estimates the parameters and the feedback gain comprising the fuzzy model representing the observation system. In the process of deriving adaptive law, the Lyapunov theory and Lipchitz condition are used. To show the performance of the proposed observer and controller, they are applied to an inverted pendulum on a cart.

• 대한기계학회논문집
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• 제19권1호
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• pp.132-141
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• 1995

The torque converter, an important component of automatic transmissions, is a hydrodynamic device which has a great influence on transient characteristics of vehicle during shift. To predict the accurate driving performance in extremely transient state such as shifting process, a detailed analysis of the torque converter is required. In this study, one dimensional performance model of the torque converter based on the concept of mean flow path, was used to analyze the shifting transients and the exact values of equivalent parameters were determined from the experimental results by using BOX program. The dynamic modelings of the components of power transmission systems such as engines, planetary gear systems, clutches and one-way clutches, were carried out. To analyze the shifting transients of tracked vehicle, a simulation program was developed. In the modeling of power transmission systems, the stiffness of shafts was neglected and shifting control logic(TCU) was included. Using the developed simulation program, the driving conditions were simulated and the results of simulation were verified through the experiments on the dynamometer.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제12권4호
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• pp.229-240
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• 2006

개량형 경보시스템은 원자력 플랜트의 경보 기능을 구현하기 위하여 최신 디지털 기술들을 적용한다. 신호검증 및 선진 경보처리 기술들을 제공하는 디지털 신기술의 사용은 제어실 운전원 연계를 향상시킨다. 본 논문은 원자력 플랜트의 개량형 경보시스템의 설계 공정, 신뢰도 예측 도구를 이용한 시스템 신뢰도 및 가용도 향상 평가, 인간공학적 성능 관점의 설계 전략 그리고 검증설비를 이용한 성능 분석의 결과 등과 같은 실제적인 구현 사례를 소개한다.

• 한국정보통신학회논문지
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• 제16권5호
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• pp.989-998
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• 2012

본 논문에서는 매우 작은 절대 값을 갖는 펨토 패럿 단위의 커패시턴스를 측정 할 수 있는 비율형 커패시턴스 측정 회로를 제안하였다. 제안한 측정 회로는 스위치 커패시터 적분기와 비교기 그리고 스위치를 제어하는 논리 회로와 카운터로 구성되어 있으며, 측정하고자 하는 커패시턴스와 이미 값이 알려진 온-칩 커패시터간의 비율을 측정하고 그 값을 디지털 신호로 출력한다. 그리고 이 비율 값을 통해 오차가 상당부분 제거된 펨토 패럿 단위의 커패시턴스를 구해낼 수 있다. 제안한 커패시턴스 측정 회로는 표준 CMOS $0.18{\mu}m$ 공정을 사용하여 설계되었으며, HSpice 시뮬레이션에서 5fF 이하의 아주 작은 커패시턴스를 오차율 ${\pm}0.3%$ 이내에서 측정이 가능함을 보였다.

• 한국안전학회지
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• 제29권1호
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• pp.86-92
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• 2014

This paper provides an integrated view on human and system interaction in advanced and automated systems, which adopting computerized multi-functional artifacts and complicated organizations, such as nuclear power plants, chemical plants, steel and semi-conduct manufacturing system. As current systems have advanced with various automated equipments but human operators from various organizations are involved in the systems, system safety still remains uncertain. Especially, a human operator plays an important role at the time of critical conditions that can lead to catastrophic accidents. The knowledge on human error helps a risk manager as well as a designer to create and control a more credible system. Several human error theories were reviewed and adopted for forming the integrated perspective: gulf of execution and evaluation; risk homeostasis; the ironies of automation; trust in automation; design affordance; distributed cognition; situation awareness; and plan delegation theory. The integrated perspective embraces human error theories within three levels of human-system interactions such as affordance level, psychological logic level and trust level. This paper argued that risk management process should dealt with human errors by providing (1) reasoning improvement; (2) support to situation awareness of operators; and (3) continuous monitoring on harmonization of human system interaction. This approach may help people to understand risk of human-system interaction failure characteristics and their countermeasures.

• 한국콘텐츠학회논문지
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• 제9권6호
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• pp.45-52
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• 2009

최근 제조업에서 제품 설계를 지원하는 디지털 전문가 시스템을 개발하는 사례가 일어나고 있다. 이 시스템은 제조업에서 엔지니어가 프로세스를 통제하고, 생산관리와 시스템 관리 등을 위하여 사용되고 있다. 본 논문에서는 전문가 시스템을 구축하기 위한 온톨로지 기반의 추론 엔진 개발에 대하여 논한다. 전문가 시스템은 한국어를 지원하고 다양한 기능을 가지며, 그래픽한 온톨로지 맵 인터페이스와 퍼지 룰 기능 정의 등의 기능을 갖도록 하였다. 또한, 온톨로지 맵 구축과 온톨로지 기반의 퍼지 추론 방법에 대하여 지식을 표현하는 방법에 대하여 설명한다.

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.12-20
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• 2018

Recently, web-based service software has been used as to combine various information or to share information according to the needs of users and the convergence of specialized fields and individual dependent systems. According to the necessity of the user, the proper service environment and the selective service environment according to the purpose and the needs of the user have been studied in a variety of specialized and combined professional research fields and industries. Software based on cloud systems and web services is being used as a tool for appropriate group and user groups and roles. A service system combined dynamically needs a module to manage a user through internal logic and grant a service access authentication. Therefore, it has been considered various approaches that a user who accesses the system is given a service access authority for a certain period of time. Also, when the deadline is over, the authority that you are given to access system will go through the process of expire the right. In this paper, we define the roles of users who access web services, manage user rights according to each role, and provide appropriate service resources to users according to their rights and session information. We analyzed the procedure of constructing the algorithm for the service according to the procedure of each user accessing the web service, granting the service resource and constructing a new role.

• 영어영문학
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• 제64권4호
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• pp.651-672
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• 2018

Death of a Salesman is centered on Willy Loman trying to achieve the American dream and taking his family along for the ride. This paper explores the meaning of his suicide in the work through the Adorno's theory on the individual's reification and commodity by an exchange value in the capitalism and argues that Bourdieu's capital classification shows the cause of his tragic decision. Reification refers to "the structural process whereby the commodity form permeates life in capitalist society." and Adorno called the reification of consciousness an epiphenomenon. The social-psychological level in Adorno's diagnosis serves to demonstrate the effectiveness and pervasiveness of late capitalist exploitation. According to Bourdieu, cultural capital can exist three forms: in the embodied state, in the objectifed state and in the instituionalized state. He states embodied capital is argued to be the most significant influence; however unlike other forms of capital (social, economic, etc.) obtaining embodied capital is largely out of the individuals' control as it is developed from birth. In conclusion, I suggest Death of a Salesman can be interpreted as a text criticizing the internalization of the subject, which is the result of the self-destructive mechanism of the subject in the logic of modern subject formation.