• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.151-156
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• 2003

The Communication Based Train Control(CBTC) System generally used to improving existing lines in the world is efficient and stable for improvement. Also it is efficient for improvement because it does not cause any problems in operation of existing lines. We examined the mixed operation scheme for more efficient and stable improvement when improvement is implemented depending on aged equipment and the increased number of passengers in the Korean city railroad. The biggest point in the mixed operation is to implement a stable test without interfering with the operation of the existing lines. For this purpose, we deduced a method of installing the equipment, a method of testing depending on the installed equipment, and the types of mixed operation, and presented a scheme of execution of the methods depending on the mixed operation.

• 정보학연구
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• 제4권4호
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• pp.51-63
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• 2001

잉여수계(Residue Number System)는 각 모듈러스에 자리올림수의 전달이 필요 없고, 병렬 구조를 이루므로, 디지털 신호처리 및 신경망 처리기와 같은 전용 프로세서 설계에서 사용된다. 그러나, 크기 비교 및 부호 검출시에 혼합기수변환(Mixed Radix Conversion)이 요구되며, 이는 전체 연산 속도를 저해하는 요인이 된다. 그러므로 본 논문에서는 혼합기수 변환의 속도를 향상시키기 위하여 잉여수 분할 방법을 개선한 혼합기수변환기를 설계하였다. 설계된 변환기는 기존의 변환기에 비하여 연산기의 크기는 증가하지만 연산시간은 최대 2배가 향상되었다.

• 대한산업공학회지
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• 제30권4호
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• pp.346-354
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• 2004

Most industrial logistic systems have focused on carrying products from manufacturers or distribution centers to customers. In recent years, they are faced with the problem of integrating reverse flows into their transportation systems. In this paper, we address the vehicle routing problems with mixed delivery and pick-up(VRPMDP). Mixed operation of delivery and pick-up during a vehicle tour requires rearrangement of the goods on board. The VRPMDP considers the reshuffling time of goods at customers, hard time windows, and split operation of delivery and pick-up. We construct a mixed integer mathematical model and propose a new genetic algorithm named GAMP for VRPMDP. Computational experiments on various types of test problems are performed to evaluate GAMP against the modified Dethloff's algorithm. The results show that GAMP reduces the total vehicle operation time by 5.9% on average, but takes about six times longer computation time.

• 한국환경보건학회지
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• 제20권4호
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• pp.10-16
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• 1994

A Study was performed in order to measure mixed organic solvent concentrations in air of painting operations during January 5-28, 1991. The mixed organic solvent concentrations were analyzed by the gas chromatography. The results were as follows: 1. The detection of organic solvent was highest in aromatic hydrocarbon(68%), and followed by aliphatic hydrocarbon (18%), and ketone (14%). 2. The detection of organic solvent by component category was highest in the grid class solvent (79.4%), and followed by the 3rd class solvent (20.6%). 3. Number of cases exceeding TLVS of mixed solvent level in air was highest on dipping operation (44%), and followed by spray operation (40%), dry and washing operation (33%), and adhensive operation (12%).

• 한국경영과학회지
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• 제30권2호
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• pp.143-156
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• 2005

Facility location planning (FLP) problem is the strategic level planning in supply chain. The FLP is significantly affected by the operation time of each facility. In most of the FLP researches, operation time of facility has been treated as a fixed value. However, the operation time is not a static factor in real situations and the fixed operation time may lead unrealistic FLP. In this paper, a mixed integer programming (MIP) model is proposed for solving the 3-stage FLP problem and operation times are adjusted by the results from the simulation model and an iterative approach combining the analytic model and simulation model is proposed to obtain more realistic operation plans for FLP problems.

• 한국학교수학회논문집
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• 제20권2호
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• pp.141-161
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• 2017

초등학교에서 자연수의 혼합계산은 사칙계산이 섞여 있는 수식의 계산 순서를 알고 해결할 수 있는 능력을 길러 주는데 초점을 두고 있다. 이런 목표에 비추어 본 연구에서는 초등학생 67명과 예비교사 57명을 대상으로 수식과 문장제로 이루어진 검사지를 이용하여 혼합계산에 대한 해결 정도와 오류 유형을 분석하였다. 검사 결과, 초등학생들은 수식과 문장제로 된 혼합계산에서 86.2%와 73.5%의 정답률과 수식에서 계산 순서의 오류, 문장제에서 수식을 구성하지 못하는 오류를 나타내었다. 예비교사들의 경우에 나타난 몇 개의 오류와 해결과정에 비추어 혼합계산이 이루어지는 식의 계산 원리와 규약을 이해할 수 있도록 교과 교육 내용을 유의해서 지도할 필요를 제시하였다. 또한 검사 결과를 통해 혼합계산 시 괄호 사용의 유무와 적절성, 등호 개념의 사용 방법에서 문제점을 확인할 수 있었다.

• Membrane and Water Treatment
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• 제7권4호
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• pp.367-375
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• 2016

Although the bucky paper (BP) made from carbon nanotubes (CNTs) possesses beneficial characteristics of hydrophobic nature and high porosity for membrane distillation (MD) application, weak mechanical strength of BP has often prevented the stable operation. This study aims to fabricate the BP with high mechanical strength to improve its MD performance. The strategy was to increase the purity level of CNTs with an assumption that purer CNTs would increase the Van der Waals attraction, leading to the improvement of mechanical strength of BP. According to this study results, the purification of CNT does not necessarily enhance the mechanical strength of BP. The BP made from purer CNTs demonstrated a high flux ($142kg/m^2{\cdot}h$) even at low ${\Delta}T$ ($50^{\circ}C$ and $20^{\circ}C$) during the experiments of direct contact membrane distillation (DCMD). However, the operation was not stable because a crack quickly formed. Then, a support layer of AAO (anodic aluminum oxide) filter paper was introduced to reinforce the mechanical strength of BP. The support reinforcement was able to increase the mechanical strength, but wetting occurred. Therefore, the mixed matrix membrane (PSf-CNT) using CNTs as filler to polysulphone was fabricated. The DCMD operation with the PSf-CNT membrane was stable, although the flux was low ($6.1kg/m^2{\cdot}h$). This result suggests that the mixed matrix membrane could be more beneficial for the stable DCMD operation than the BP.

• 전기학회논문지
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• 제62권11호
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• pp.1610-1616
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• 2013

Recently, district heating and cooling (DHC) systems based on combined cycle generation (CCG) providers are increasing in Korea. Since characteristics of combined heat and power (CHP) generators and heat demands of providers, heat trading between DHC providers based on the economic viewpoint is required; the heat trading has been doing. In this paper, a mathematical model for optimal operation based on heat trading between DHC providers is proposed. Especially, start-up characteristic of CCG is included. The operation model is established by mixed integer linear programming (MILP).

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1996년도 제6회 학술강연회논문집
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• pp.197-205
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• 1996

A combined extrusion process studied here consists of forward and backward extrusion, and it is formed in single operation. The metal flow involved in the operation has appeared to be difficult to analyze accurately because of mixed directions of the flow. In this study, conventional two operations of a forward and a backward extrusions is transformed into one operation of mixed extrusion. A process designed by an industry expert is simulated by the rigid-plastic finite element method to investigate the metal flow and defects. In addition to the FEM simulation, experimental analysis has been carried out to confirm the design in industry, which includes material characterization, preliminary expriment, and whole experimental forming operation. The experimental results show that warm forming of extrusion is more desirable than cold working and hot forming in view of grain growth. Also two conditions of lubrication between workpiece and die has been investigated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.245-248
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• 1997

The control modes used in teleoperation are position control mode, and rate control mode. This paper presents the problems of the conventional control modes, through simulation, proposes an intelligent mixed control mode that converts the operation mode between the position mode and the rate mode intelligently by judging the operator's intention using the real-time measurement data. The effectiveness of the proposed intelligent mixed control mode is demonstrated and compared to other typical control modes through simulation and actual experiment.