• 산업공학
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• 제12권2호
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• pp.346-353
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• 1999

In this paper, the optimum drilling operation sequence which results into the minimum overall machining time required to produce a (multi-diameter) hole is identified. The operation sequence is defined as the set of ordered operations used for producing a (multi-diameter) hole. The overall machining time is derived by summing the minimum machining times of each operation assigned to a sequence. The operations represent the drilling actions of certain sizes to produce the related holes. The minimum machining time of each operation is obtained by solving the optimization problem. Finally, this paper will identify the effects of machining constraints on the overall machining times and their relationships to sequence selection.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1134-1139
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• 2009

Haul routes for earthmoving operation need to be carefully selected because the decision on the haul routes could make a significant difference in the project's cost and time. This paper proposes a decision support system for improving productivity of earthmoving operation that helps construction managers choose the best haul routes of trucks based on time slots. Also, a methodology for optimal selection of haul routes considering traffic conditions and topographic conditions of the routes is explained. Raster data model is used to find an available shortest path based on cost weighted distance. A system was developed on a geographic information system environment for efficient database management and easy manipulation of graphical data. A real-world case study was conducted to verify the applicability of the proposed system.

• 대한산업공학회지
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• 제27권3호
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• pp.315-327
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• 2001

This paper considers the problem of operation sequencing in nonlinear process planning, which is the problem of selecting and sequencing operations required to produce a part with the objective of minimizing the sum of operation processing costs and machine, setup and tool change costs. Main constraints are the precedence relations among operations. The problem can be decomposed into two subproblems: operation selection and operation sequencing. We suggest four simulated annealing algorithms, which solve the two subproblems iteratively until a good solution is obtained. Here, the operation selection problem can be solved using a shortest path algorithm. Application of the algorithms is illustrated using an example. Also, to show the performances of the suggested algorithms, computational experiments were done on randomly generated test problems and the results are reported. In particular, one of the suggested algorithms outperforms an existing simulated annealing algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.80-87
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• 2001

The purposes of this primary study are the selection of rail station and train operation management techniques for express-rail operation service at the convectional railway electrification. For these analyses, we used the KNR statistics and KROIS data of rail stations and train users by rail line. Therefore, we chose the important stations for express-rail operation of Kyongbu conventional rail line (esp. Seoul-Jochiwon section) through the rail transportation demand. and then, suggested primary operational management plan thorough the effects analyses of decreasing total travel time and increasing transportation demand by train speed-up. This study has some bounds and limits for proceeding, as it does, we excluded as followings: the conditionals of fate system, headways and train diagram, economic/financial analysis and technological assessment, and other railway technological infrastructures and a certain railcar specification, etc. . We propose to enlarge this study into a feasibility study of express or skip-stop operation service and compatible vehicle system decision considering with the best possible investment rail line, furthermore. in front of Kyongbu (Seoul-Busan) high-speed rail open in 2004, we have to try to progress the efficiencies of railway operation applying various train operation management plan.

• 대한지역사회영양학회지
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• 제9권2호
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• pp.183-190
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• 2004

This study was designed to identify how customers considered menu selection attributes on menu choice, and so the instrument for measuring that question was developed and menu selection behavior types were analyzed by customers' characteristics. Cronbach's alpha to assess the internal reliability of the developed scales was 0.8361, which indicated to be highly reliable. Construct validity was assessed by principal components factor analysis with a Varimax rotation to identify underlying dimensions of menu selection and then four factors explaining 55.618% of the total variance were found. These factors were labeled as 'quality of meals', 'attractiveness of meals', 'healthfulness of meals' and 'variety of meals', respectively. As a result of analysis on menu selection factors, 'quality of meals'(3.82 out of 5) was the highest consideration followed by 'variety of meals'(3.51), 'healthfulness of meals'(3.49) and 'attractiveness of meals'(3.34), so that menu marketing approaches in the perspective of quality of meals would do lead customers' selection rates, customer satisfaction and then sales highly. Frequent visitor selected menu indifferently but customers who were interested in food and menu highly, who perceived meals' quality highly, and who were satisfied with overall foodservice did with concern. On the basis of these results of study for the target of food court-style B ＆ I foodservice operation, which was introduced as an ideal model in future foodservice market by the concept of 'customer's selection right', the following study related with customers' meal patterns and perception of foodservice by menu selection attributes would be able to predict the chances for success of food court-style foodservice operations.

• 대한기계학회논문집
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• 제16권4호
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• pp.696-706
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• 1992

본 연구에서는 공구선정 작업의 자동화를 목표로 하였다.공구선정을 완전 자동으로 행하기 위해 해결해야 할 문제는, 현재 공구대(turret)에 장착되어 있는 공 구중에서 어떤 공구를 얼마칸큼 직선, 회전 이동시키면 판재 경계와 정확하게 일치하 는가 하는 문제와, 복잡한 형상의 펀칭을 위해선 효과적인 공구조합은 어떻게 해야하 나 하는 문제로 귀결되므로 이 두가지 문제의 해결방안을 기술한다.

• 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.

• 한국정보기술학회 영문논문지
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• 제10권1호
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• pp.1-14
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• 2020

Antenna selection is a method to enhance the performance of spatial multiplexing multiple-input multiple-output (MIMO) systems, which can achieve the diversity order of the full MIMO systems. Although various selection criteria have been studied in the literature, they should be adjusted to the detection operation implemented at the receiver. In this paper, antenna selection methods that optimize the post-processing signal-to-noise ratio (SNR) and eigenvalue are considered for the lattice reduction (LR)-based receiver. To develop a complexity-efficient antenna selection algorithm, the incremental selection strategy is adopted. Moreover, for improvement of performance, an additional iterative selection method is presented in combination with an incremental strategy.

• 시스템엔지니어링학술지
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• 제15권1호
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• pp.25-33
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• 2019

In the plant industry, the share of equipment accounts for 45 ~ 75%, which is very high. It is a traditional plant centered on processes and reactions like petroleum and chemical plants. Renewable energy generation plants such as wind power generation and solar power generation are equipment-centric plants. Equipment-centric plants are very important not only in the EPC phase but also in the operation and management phase. The procurement of equipment for plant operation and management can be divided into make and buy. Make is a method of producing equipment itself, and buy is a method of procuring equipment from the outside. The procurement method of the equipment directly affects the plant operation and management cost. In this study, the decision making of equipment procurement method for plant operation and management is defined as 4 phase. Each phase is selection of procurement decision-making objects, technology strategy perspective, finance perspective, and production perspective. In detail, we defined selection process of procurement decision-making objects and technology strategy perspective process. We will contribute to the enhancement of the competitiveness of the plant operation and management area by carrying out researches on the process and application examples of financial and production perspectives in the future.

• 경영과학
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• 제33권3호
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• pp.1-18
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• 2016

Recently, ordinary mail is decreasing continuously by the development of ICT (Information and Communications Technology) including E-mail, messenger service, and etc. On the contrary, parcel post is increasing by the increase of online shopping, home shopping, and etc. Aside from these changes, the demand for various mail acceptance and delivery means is increasing with the increase of single households and dual-income couples. To overcome these environmental changes, Korea Post installs unmanned post offices which are composed of various unmanned mail acceptance and delivery postal systems. In this paper, we propose the methodological approach for the site selection of unmanned post office among the existing post offices and the installation standard of unmanned postal system considering the operation cost by the mail volume.