• Journal of the Korean Society of Systems Engineering
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• 제16권1호
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• pp.84-97
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• 2020

This paper aims to develop an optimized inventory management method for safety critical Instrument and Control (I&C) components. In this regard, the paper focuses on estimating the consumption rate of I&C components using demand forecasting methods. The target component for this paper is the Foxboro SPEC-200 controller. This component was chosen because it has highest consumption rate among the safety critical I&C components in Korean OPR-1000 NPPs. Three analytical methods were chosen in order to develop the demand forecasting methods; Poisson, Generalized Linear Model (GLM) and Bootstrapping. The results show that the GLM gives better accuracy than the other analytical methods. This is because the GLM considers the maintenance level of the component by discriminating between corrective and preventive.

• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.717-723
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• 2011

When the Balise(the device to transmit information between the on-board equipment and the wayside equipment) failure occurs, it may not be able to transmit data(Telegram) required for the train running. And in some cases, it may be able to cause an accident. Therefore, both the Balise failure affecting train safety running and the hazard in accordance with Balise failure require some activities to establish them. General failure mode & hazard analysis associated with the Balise are described in UNISIG SUBSET-036 spec & UNISIG SUBSET-088 spec. And, with reference to these specifications, safety activities are being performed. In recent domestic railway, the train control system applying ETCS(European Train Control System) Level 1, 2 is being serviced and is being planned, and as part of this system, the Balise is being applied. The design-method of the Balise device for each manufacturer are different, therefore the Balise failure mode & failure rate are different, either. But the functionalities & transmission-data format(Telegram) of the Balise in ETCS Level 1, 2 application for each manufacturer are identical. Accordingly, the hazard caused by function-fail can be identical, either. In order to establish these hazard, in this paper, we analyzed the detailed functions of the Balise. And we analyzed the Balise failure types & failure effects in accordance with the detailed functions.

• Journal of Fashion Business
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• 제7권5호
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• pp.32-44
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• 2003

In apparel industry, the worksheet or product specification document has the function of products design. Drawing up worksheet exactly is important to quality control of apparel products. Every company needs to manage the product data of design-centric to establish TQM environment. In order to control the quality data of design-centric, an apparel worksheet system was developed by using the function of product data management system.

• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.880-882
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• 1995

The systematic function of the PLC (Programmable - Logic Controller) has been enhanced immensely due to the various special modules that consist of the conventional I/O control contants plus special function, which enables the flexible application to highly advanced systems. Position control module is one of the various PLC special module. In this paper, we proposed new synchronized operating method and implemented 8 - axis servo control system. The validity of proposed method is verified througth experimental results and it will be possible to expand 32 - axis servo control system by RS - 485 communication spec.

• The Magazine of the IEIE
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• 제18권6호
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• pp.39-46
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• 1991

칼라 비데오 프린터의 paper feeding 제어 시스템을 DC motor를 이용하여 설계하였다. 목표 spec을 만족하기 위한 H/W를 구성한 후 digital control 이론을 적용하여 loop gain K를 찾고 위상계와 속도계 gain을 결정하는 방법을 설명하였다. 한편 DC analysis를 통하여 앞에서 결정된 gain으로 설계할 경우 parameter variation에 의해 동작점이 벗어나는 것을 확인하고 system 구성 및 gain 등을 조정하여 동작점의 안정화를 가져올 수 있었다. 또한 DC analysis를 함으로써 부품의 공차를 설계할 수 있었다.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.375-377
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• 1998

This paper shows two models of the TMR system- fail passive system - having a fault tolerant system characteristic used in airplane and railway system. We design the single system, single-voter TMR system and triplicated voter TMR system based on MC68000 and calculate the failure rate of components using MIL-SPEC-217F and evaluate the reliability and MTTF(Mean Time To Failure) of the designed systems by Markov model.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제16권3호
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• pp.39-52
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• 2006

Recently purpose is used by an crucial part to security management when collecting data about privacy. The W3C(World Wide Web Consortium) describes a standard spec to control personal data that is provided by data providers who visit the web site. But they don't say anymore about security management about personal data in transit after data collection. Recently several researches, such as Hippocratic Databases, Purpose Based Access Control and Hippocratic in Databases, are dealing with security management using purpose concept and access control mechanism after data collection a W3C's standard spec about data collection mechanism but they couldn't suggest an efficient mechanism for privacy protection about personal data because they couldn't represent purpose expression and management of purposes sufficiently. In this paper we suggest a mechanism to improve the purpose expression. And then we suggest an accesscontrol mechanism that is under least privilege principle using the purpose classification for privacy protection. We classify purpose into Along purpose structure, Inheritance purpose structure and Stream purpose structure. We suggest different mechanisms to deal with then We use the role hierarchy structure of RBAC(Role-Based Access Control) for flexibility about access control and suggest mechanisms that provide the least privilege for processing the task in case that is satisfying using several features of purpose to get least privilege of a task that is a nit of business process.

• Journal of the Korean Society of Mechanical Technology
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• 제20권6호
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• pp.865-871
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• 2018

The 3-way valve have been used as a valve for opening and closing the valve by the flow control in the pressure system of the cryogenic and high pressure environment. In this paper, numerical analysis and experimental study on fracture nipple of 3-way ultra high pressure valve applied to space launch vehicle was carried out. We have developed a 3-way valve numerical simulation modeler of cryogenic environment using commercial software ANSYS 18.2. As results of numerical analysis, optimum nipple condition was derived. In addition, a 3-way valve prototype was fabricated and the fracture test was performed and compared with the numerical analysis results.

• Proceedings of the KOSOMBE Conference
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.22-24
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• 1996

Small size DC motor control method for portable drug delivery system has been developed to be used for the actuator of insulins pump. The control method gives the controllabilities both in high speed(40-50 revolution per second(rps)) DC motor drive and also in low speed(0.5-1rps). In low speed mode DC motor is controlled to act like stepping motor and in high speed to optimize power consumption. To control both mode modified bang bang control is suggested. Using this method small size DC motor(spec.) speed is controlled from 0.2 rps to 50 rps. Experimental setup is developed using micro-processor(PIC16C73, Micro Chips co., USA), motor turns checking circuitry, small size DC motor for pager(SM1012, Samhong co., Korea) and gear box. Results from experiment meet need for vailable load condition which is require for portable drug delivery system.

• Journal of Institute of Control, Robotics and Systems
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• 제11권2호
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• pp.152-159
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• 2005

This paper describes the application of a model-based system design method critical to complex intelligent systems, PSARE, to a welding robot development to define its top level architecture. The PSARE model consists of requirement model which describes the core processes(function) of the system, enhanced requirement model which adds technology specific processes to requirement model and allocates them to architecture model, and architecture model which describes the structure and interfaces and flows of the modules of the system. This paper focuses on the detailed procedure and method rather than the detailed domain model of the welding robot. In this study, only the top level architecture of a welding robot was defined using the PSARE method. However, the method can be repeatedly applied to the lower level architecture of the robot until the process which the robot should perform can be clearly defined. The enhanced data flow diagram in this model separates technology independent processes and technology specific processes. This approach will provide a useful base not only for improvement of a class of welding robots but also for development of increasingly complex intelligent real-time systems.