• 산업경영시스템학회지
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• 제34권4호
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• pp.152-161
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• 2011

The operation of vending machine system presents a decision-making problem which consists of determining the product allocation to vending-machine storage compartments, replenishment intervals of vending machines, and vehicle routes, all of which have critical effects on system profit. Especially, it becomes more difficult to determine the operation variables optimally when demand for a product that is out-of-stock spills over to another product or is lost. In this paper, we propose a heuristic for solving the operation problem of the vending machine system and evaluate it by comparing with Yang's algorithm on various test problems with respect to system profit via a computer simulation. The results of computational experiments show a substantial profit increase of the proposed heuristic over Yang's algorithm. Sensitivity analysis indicates that some input variables impact the profit increase significantly.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (A)
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• pp.273-274
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• 2007

• 전기저널
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• 5호통권101호
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• pp.29-35
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• 1985

• 대한전기학회논문지
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• 제36권7호
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• pp.476-483
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• 1987

This paper analyzes centralized sampled-data control systems with feedback loops which are closed through a digital computer which generates deadbeat control law. Intermittant computer interruptions result in failure to update the desired deadbeat design procedures for the deadbeat control law under normal operation of the control computer and the assumption of any admissible computer interruption are resented. A method that guarantees asymptotic stability under all admissible computer interruptions also is presented.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.167-173
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• 2017

In this paper, the characterization of the vertical position of trapped charges in the charge-trap flash (CTF) memory is performed in the novel CTF memory cell with gate-all-around structure using technology computer-aided design (TCAD) simulation. In the CTF memories, injected charges are not stored in the conductive poly-crystalline silicon layer in the trapping layer such as silicon nitride. Thus, a reliable technique for exactly locating the trapped charges is required for making up an accurate macro-models for CTF memory cells. When a programming operation is performed initially, the injected charges are trapped near the interface between tunneling oxide and trapping nitride layers. However, as the program voltage gets higher and a larger threshold voltage shift is resulted, additional charges are trapped near the blocking oxide interface. Intrinsic properties of nitride including trap density and effective capture cross-sectional area substantially affect the position of charge centroid. By exactly locating the charge centroid from the charge distribution in programmed cells under various operation conditions, the relation between charge centroid and program operation condition is closely investigated.

• 공학교육연구
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• 제9권3호
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• pp.22-36
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• 2006

이 연구는 컴퓨터운용사의 구체적인 직무 분석을 통하여 컴퓨터 운용사 자격의 출제기준을 개선하는데 목적이 있다. 연구목적을 달성하기 위해서 본 연구에서는 산업계, 학계 전문가 7명으로 구성된 직무분석 위원회에서 데이컴(DACUM: Development A curriculum)법으로 직무분석을 실시하여 직무범위, 등급, 응시자격, 검정 기준, 출제 기준, 검정 방법 등의 구성 내용을 추출하였다. 또한 이 연구에서는 컴퓨터 운용사의 출제기준을 개발을 위한 직무분석의 모형을 절차별로 정리 제시하였는데, 1단계는 직무분석 준비(자료 조사 및 면담, 전문가 선정), 2단계는 직무모형 설정(1차 전문가 협의회 및 1차 현장 검토)하였고, 3단계는 지식, 기능, 도구 추출(2차 전문가 협의회 및 2차 현장 검토), 4단계는 코스 및 교과목 선정(3차 전문가 협의회), 5단계는 출제기준 설정(3차 현장 검토)의 과정을 통하여 컴퓨터운용사의 자격의 출제기준을 제시하였다.

• 한국항공우주학회지
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• 제47권10호
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• pp.728-737
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• 2019

본 연구에서는 초소형 위성을 이용한 위성 편대 및 군집 운용 시 실시간으로 위성 간의 상대 위치 정보를 제공할 수 있는 통합 항법용 모듈형 온보드 컴퓨터(On-board Computer, OBC)를 개발하였다. 모듈은 구조적으로는 큐브위성의 기준 규격에 맞게 설계하되 사용자가 원하는 무선 통신모듈 및 항법용 Global Positioning System(GPS) 장비를 적용할 수 있도록 확장성을 고려하였다. 개발된 OBC는 제품 개발 및 제작 이후 야외 테스트를 통해 저전력 Micro Controller Unit(MCU)로 군집 운용을 수행하는 초소형 위성들의 통합 항법 및 실시간 데이터 동기화 요구 처리속도를 만족함을 확인하였다. 또한, 열진공, 방사능 시험을 거쳐 우주급 환경에서 정상 작동함을 확인하였으며, 진동시험의 경우 underfill 공정을 추가하면 정상적으로 요구조건을 만족할 수 있음을 확인하였다. 이를 통해 향후 수요가 늘어날 군집 운용을 위한 위성군 개발의 핵심 부품인 OBC의 대량생산 체계를 구축하였다.

• 한국안전학회지
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• 제12권1호
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• pp.60-70
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• 1997

Since, human error is a major factor contributing to disaster during start-up of operation in Boiler plant. it is necessary to develop an automation system which prevent mode of operation that are known to be dangerous and to bring a loss of energy. The aim of this study is to suggest a model for the computer-aided synthesis of operation sequence as a part of automation system for start-up operation. Synthesis is accomplished by the formation of a hierarchical network of goals which decide sequence of operations. Hierarchical Network is formed by using method which upper goals ( i.e. upper operation al situation) are classified by the function of themselves into lower goals (i.e. lower operational situation). Knowledge for deciding operation sequence is generated by putting In order the knowledge of hazard operation and energy management.

• 공학교육연구
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• 제19권2호
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• pp.60-69
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• 2016

This paper deals with the selection method of effective engineering design problem based on LEGO Mindstorm NXT for basic design education. By YouTube case study of various LEGO-based engineering designs for olympic sports, performance criteria have been developed including programming complexity, structural complexity, sensor/actuator complexity and variety of game operation. Programming complexity includes range of programming code length and possible program variety. Structural complexity includes variety of structural elements such as length, shape, weight, and volume to overcome design restrictions. Sensor/actuator complexity includes variety of sensor used and number of possible actuator assemblies. Variety of game operation includes game complexity and required creativity to make LEGO robots. Based on these performance criteria, four representative sports were selected as the candidates for effective engineering design problem. Finally, feasibility and attributes of each candidate were verified by real implementation examples.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.2.1-2.7
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• 2018

With the development of computer-aided design/computer-aided manufacturing (CAD/CAM) technology, it has been possible to reconstruct the cranio-maxillofacial defect with more accurate preoperative planning, precise patient-specific implants (PSIs), and shorter operation times. The manufacturing processes include subtractive manufacturing and additive manufacturing and should be selected in consideration of the material type, available technology, post-processing, accuracy, lead time, properties, and surface quality. Materials such as titanium, polyethylene, polyetheretherketone (PEEK), hydroxyapatite (HA), poly-DL-lactic acid (PDLLA), polylactide-co-glycolide acid (PLGA), and calcium phosphate are used. Design methods for the reconstruction of cranio-maxillofacial defects include the use of a pre-operative model printed with pre-operative data, printing a cutting guide or template after virtual surgery, a model after virtual surgery printed with reconstructed data using a mirror image, and manufacturing PSIs by directly obtaining PSI data after reconstruction using a mirror image. By selecting the appropriate design method, manufacturing process, and implant material according to the case, it is possible to obtain a more accurate surgical procedure, reduced operation time, the prevention of various complications that can occur using the traditional method, and predictive results compared to the traditional method.