• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.211-215
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• 1997

Localized communication networks for office automation, security monitoring, environmental management of buildings, computer communications, and other applications enjoy every increasing demand. This paper proposes a direct sequence spread spectrum communication system for use in power line data transmission. Advantages of power distribution circuits include reasonably universal coverage and easy access vis a standard wall plug. Disadvantages include limited communication bandwidth, relatively high noise levels, and varying levels of impedance, noise, and attenuation. Spread spectrum signalling provides immunity to narrow-band signal impairments and multiplexing capability. Our prototype power line communication module supports completely physical and data link layers based on the international standard ISO 10368 for reliable high-speed power line communication system. Moreover it provides useful functions to compose a plant monitoring and control system. All the circuits of the communication module are included in one compact circuit. Thus a functional communication system for the power line plant monitoring and control is implemented.

• 한국해양공학회지
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• 제23권2호
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• pp.87-91
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• 2009

The welding distortion of a hull structure in the shipbuilding industry is inevitable at each assembly stage. The geometric inaccuracy caused by welding distortion tends to preclude the introduction of automation and mechanization and requires additional man-hours for adjustment work during the following assembly stage. To overcome this problem, a distortion control method should be applied. For this purpose, it is necessary to develop an accurate prediction method that can explicitly account for the influence of various factors on the welding distortion. The validity of this prediction method must also be clarified through experiments. For the purpose of reducing the weld-induced bending deflection, this paper proposes the plastic counter-deforming method (PCDM), which uses line heating as the optimum distortion control method. The validity of this method was substantiated by a number of numerical simulations and actual measurements.

• Journal of the Korean Statistical Society
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• 제23권2호
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• pp.403-420
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• 1994

An economic design of the $\bar{X}-R$ chart using variable sample size (VSS) scheme is proposed in this paper. In this design the sample size at each sampling time changes according to the values of the previous two sample statistics, sample mean and range. The VSS scheme uses large sample if the sample statistics appear near inside the control limits and smaller sample otherwise. The set of process parameters, such as the sampling interval, control limits and the sample sizes, are chosen to minimize the expected cost per hour. The efficiency of the VSS scheme is compared to the fixed sample size one for cases where there is multiple of assignable causes. Percent reductions of the expected cost in the VSS design are calculated for some given sets of cost parameters. It is shown that the VSS scheme improves the confidence of the procedure and performs statistically better in terms of the number of false alarms and the average time to signal, respectively.

• 조명전기설비학회논문지
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• 제28권9호
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• pp.28-34
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• 2014

A claw pole stepping motor is widely used in various fields such as a compact optical disk drive, computer peripherals, digital cameras, office automation(OA), handheld mobile devices, because it has the suitable structure for compact motor. However 3D analysis is essential for design of Claw pole stepping motor because of axial flux path. Thus, in general, it takes a lot of time in the design of Claw pole motor. In this paper, magnetic equivalent circuit considering axial flux was proposed to reduce design time of Claw pole motor and we has designed by using the magnetic equivalent circuit. In addition, in oder to verify the study, design model was verified by 3D FEM simulation and experiment.

• 산업공학
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• 제12권3호
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• pp.401-405
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• 1999

We present a simulation model to generate the spatial distribution of mobiles in cellular communication network. Three types of spatial distributions are considered; biased, random, and ratio-based distributions. This study also points out and corrects the critical errors performed by Das and Morgera(1997) in getting random location of mobiles. By applying a simple path loss model, the effects of our correction on the signal-to-interference(SIR) ratio are discussed. The numerical results indicate that the variation of SIR in the Das's biased distribution is larger than that of other distributions. As compared with the random distribution, the average SIR error of the biased distribution is 91.1%.

• 경영과학
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• 제8권1호
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• pp.71-89
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• 1991

최근 기업에서는 사무생산성을 향상시키기 위하여 조직의 특성에 맞는 사무자동화 기기를 도입하여 운영하고 있다. 조직에 따라 OA추진 방식이 다양하므로 OA 추진현황을 분석하여 성공적으로 OA를 추진할 수 있는 방안을 제시할 수 있다면 의미가 있다고 하겠다. 본 연구에서는 현재 우리나라의 OA현황을 조사분석하여 기업이 OA를 추진하는데 가장 적합한 추진방향을 제시하는 것을 목적으로 한다. 따라서 개략적인 OA추진운영 현황을 파악한 후 추진특성별 운영방식과 추진운영별 도입성과를 확인하여 OA도입성과를 극대화하는 추진방향을 제시하고자 한다. 연구조사를 위해 OA 추진 업체와 OA 관련 종사자를 대상으로 우편 설문조사를 실시하여 자료를 수집하였다. 연구결과는 대기업의 경우 OA가 일정수준에까지 도달하였으며, 대부분 장단기계획을 수립한 후에 OA를 추진하고 있으나 투자비용 제한, 개발인력 부족, OA기기에 대한 저항감과 같은 문제점을 안고 있는 실정이므로 이러한 문제점을 해결할 수 있는 방안을 마련하여 OA를 활성화하는 것이 바람직하다. OA실무자는 단순반복업무를 담당하고 있어 업무처리와 관리방식 개선과 같은 근본적인 업무를 거의 하지 못하고 있다. OA도입성과를 극대화하여 성공적으로 OA를 추진운영하기 위해서는 장기계획을 수립하여 추진하고 실무자의 의견을 반영하여 중대형 컴퓨터와 연계활용해야 하는 것으로 나타났다.

• 전자공학회논문지C
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• 제36C권6호
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• pp.1-8
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• 1999

회로 분할 문제에 있어서 서열화는 k분 분할의 좋은 해를 얻는 방법으로 사용되어 왔다. 서열화는 구획화 과정을 거쳐 클러스터를 구성함으로서 분할이 완료된다. 본 논문에서는 이렇게 구성된 클러스터를 재비치하여 다시 구획함으로서 향상된 해를 얻는 알고리즘을 제시하였으며, 이를 여러 가지 대상회로에 대해 실험하여 향상된 결과를 얻었다.

• 한국컴퓨터정보학회논문지
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• 제7권4호
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• pp.182-187
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• 2002

본 논문은 최근 다양한 인터넷 활용 기법을 적용하여 국한된 사무자동화에 대한 업무의 효율적 향상을 위해 많은 노력을 아끼지 않고 있다. 이에 대한 본 논문은 웹 관리 시스템 설계 및 구현을 바탕으로 기업 내 업무의 효율성을 기하기 위해, 인트라넷 구축과 이를 웹 기반 시스템으로 업무를 연장시켜 기업의 생산적인 이익을 창출하기 위한 전자상거래 시스템으로 구현함을 제시하고, 그에 따른 보안문제와 기업업무 적용차원에서 타당성을 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.450-452
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• 2001

In this paper, we proposed the automatic postal drop-off system based on the microprocessor board or PC. The weight of the small postal package is transmitted from the electronic scale and user-entered addresses and delivery rate are processed by the controller to calculate the fee. For 24 hour out-door operation and maintenance, non-cash payment methods such as credit card payment is used. The post stamp and receipt are printed by the thermal printer. For the electronic processing of the parcel, serial code is also printed on the stamp and receipts in bar code format. The parcel information obtained by the automatic postal drop-off system is transferred to remote central system by dial-up modem shared by the on site office. The proposed system and its control software are built for prototype model operation and the result met the design requirements. For real time processing, data reception through three serial ports is handled by interrupt routine. The proposed system is expected to be applied for commercial logistics system and pc automation system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.179.3-179
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• 2001

This paper describes the dual system technology of PC based control system at steel plant. Because PC is developed to be used in wide area such as Office Automation, Personal, It is cheaper and more portable than the present process control system, but is less stable and less reliable. In this research, We gathered the fault example of a general process control system and steel process control system, analyzed the cause of fault and decided the target fault that took over in our proposed system. The proposed PC based system is the dual system that has a shared RAID system connected by SCSI bus between two systems. In order to assist system reliability, we proposed watchdog manager to monitor ...