• Title/Summary/Keyword: Secondary Operations

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A Design Problem of a System Working at Both Primary Service and Secondary Service (주서비스와 보조서비스를 갖는 시스템 설계)

  • Kim, Sung-Chul
    • Korean Management Science Review
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    • v.28 no.3
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    • pp.15-29
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    • 2011
  • In this paper, we consider a system working at both primary service and secondary service. A server can switch between the primary service and the secondary service or it can be assigned to secondary service as a dedicated server. A service policy is characterized by the number of servers dedicated to the secondary service and a rule for switching the remaining servers between two services. The primary service system is modelled as a Markovian queueing system and the throughput is a function of the number of servers, buffer capacity, and service policy. And the secondary service system has a service level requirement strategically determined to perform the service assigned. There is a revenue obtained from throughput and costs due to servers and buffers. We study the problem of simultaneously determining the optimal total number of servers, buffers, and service policy to maximize profit of the system subject to both an expected customer waiting time constraint of the primary service and a service level constraint of the secondary service and develop an algorithm which can be successfully applied with the small number of computations.

Reoperations for valvular heart disease: report of 29 cases (심장판막 재수술: 29례 보)

  • 김은기
    • Journal of Chest Surgery
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    • v.16 no.4
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    • pp.498-505
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    • 1983
  • It has been over 20 years since successful operations of Cardiac valves at the Department of Thoracic and Cardiovascular surgery, college of medicine, Yonsei University. About six hundreds of patients with severely symptomatic valvular heart disease have had valve operations with complete loss or sharp decrease in their cardiac symptoms since 1956. As the number of cardiac patient increases, reoperation on valves assumes greater importance. To define the group of patients undergoing reoperations on valves and the factors influencing their survival, we have reviewed our experiences of the reoperation on valves at the Yonsei University, Severance Hospital. This is a report of 29 cases which was undergone secondary or more surgery for valvular heart disease from 1966 to 1983. The primary operations includes 159 cases of open heart surgery from 1966 to 1975 and 476 cases from 1976 to march, 1983. The secondary operations are classified into groups of secondary valvuloplasty or valvotomy [8 cases], prosthetic valve replacement following valvuloplasty or valvotomy [14 cases] and prosthetic valve rereplacement [2 case] for such as calcification, degeneration and perforation of the cusps and paravalvular leakage, of the bioprosthetic valves. The leading indication for reoperation of mitral valve was restenosis or stenoinsufficiency, The indications of aortic valve replacement was active bacterial endocarditis, medically uncontrollable prosthetic endocarditis or paravalvular leakage. Overall death rate of the reoperation was 17.4% [5 death among the 29 patients] and the leading causes of death were myocardial failure, arrhythmia, cerebral embolism, acute renal failure due to low output syndrome. And it was followed by sepsis associated with active prosthetic endocarditis. The death rate of reoperation was 4.3% in the elective cases except urgent cases and the death rate of overall cardiac valve except reoperation cases was 4.1% in the last two years. Although the general mortality of reoperation was high, both mortality rates were comparable except emergency cases due to urgent preoperative patient’s condition.

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A Dispatching Method for Automated Guided Vehicles to Minimize Delays of Containership Operations

  • Kim, Kap-Hwan;Bae, Jong-Wook
    • Management Science and Financial Engineering
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    • v.5 no.1
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    • pp.1-25
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    • 1999
  • There is a worldwide trend to automate the handling operations in port container terminals in an effort to improve productivity and reduce labor cost. This study iscusses how to apply an AGV(automated guided vehicle) system to the handling of containers in the yard of a port container ter-minal. The main issue of this paper is how to assign tasks of container delivery to AGVs during ship operations in an automated port container terminal. A dual-cycle operation is assumed in which the loading and the discharging operation can be performed alternately. Mixed integer linear program-ming formulations are suggested for the dispatching problem. The completion time of all the dis-charging and loading operations by a quayside crane is minimized, and the minimization of the total travel time of AGVs is also considered as a secondary objective. A heuristic method using useful properties of the dispatching problem is suggested to reduce the computational time. The perfor-mance of the heuristic algorithm is evaluated in light of solution quality and computation time.

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A Study on the Forming of Parts for Automobile using Fine Blanking Process (파인블랭킹 공정을 이용한 자동차용 부품의 가공에 관한 연구)

    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.2
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    • pp.56-61
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    • 1999
  • The fine blanking is a process of pressworking which makes possible to produce thick sheet metal parts of finished sheared surface and close dimensional accuracy over whole material thickness in single blanki ng operation. Fine blanked parts in general are characterized by their cleanly sheared surface over the whole sock thickness and accurate size for the specific functions. The fine blanking technology is urgently needed to remove secondary operations which are necessary in conventional blanking operation and cost reduction. In this study, the effect of material texture and vee-ring on parts for automobile is investigated by experimental observation and analysis.

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Research for The Chain Sprocket Produce by Fine Blanking (복합 Fine Blanking 공정을 이용한 Chain Sprocket 개발을 위한 연구)

  • 강태호;김인관;조광수;김영수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1597-1600
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    • 2003
  • Fine-Blanking is an advanced and precision stamping process, by which a component with precise geometry and smooth cut surface can be produced without any further major secondary operations. By applying the Fine-Blanking technology, the significant improvement of the component should be obvious. As the components are with good shape, smooth surface and precise size, they can be ready for assembly without any further secondary operations. The productivity is increased, the production cycle time and the component cost are significantly reduced. We apply the fine-Blanking for chain sprocket. And do Mecanical test for compress strenth. impaact, roughness, Brinell hardness, dimensional stability.

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A Design Problem of a Service System with Bi-functional Servers (이중작업능력의 서버로 구성된 서비스시스템 설계)

  • Kim, Sung-Chul
    • Journal of the Korean Operations Research and Management Science Society
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    • v.32 no.3
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    • pp.17-31
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    • 2007
  • In this paper, we consider a service system with bi-functional servers, which can switch between the primary service room and the secondary room. A service policy is characterized by the switching paints which depend on the queue length in the primary service room and the service level requirement constraint of the secondary room. The primary service room is modeled as a Markovian queueing system and the throughput of the primary service room is function of the total number of bi-functional servers. the buffer capacity of the primary service room, and the service policy. There is a revenue obtained from throughput and costs due to servers and buffers. We study the problem of simuitaneously determining the optimal number of servers, buffer capacity, and service policy to maximize profit of the service system, and develop an algorithm which can be successfully applied with the small number of computations.

Statistical Analysis of Sewage Plant Operation (하수처리장 운전조건의 통계분석)

  • 이찬형;문경숙
    • Journal of Environmental Science International
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    • v.11 no.1
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    • pp.63-68
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    • 2002
  • In this study, we examined statistical analysis between sewage plant operations parameters and effluent quality We got six components from principle component analysis of the operation parameters and secondary effluent quality. 91.8% of the total variance was explained by the six components. The components were identified in the following order : 1) organic matter removal by aeration basin microbe, 2) settleability on secondary clarifier load, 3) removal of nutrients, 4) microbial number increasement and species diversity, 5) microbial activity in aeration basin, 6) oxidation in aeration basin.

Network Enlarging Search Technique (NEST) for the Crew Scheduling Problem

  • Paek, Gwan-Ho
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.2
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    • pp.177-198
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    • 1994
  • We consider an algorithm for the Crew Scheduling Problem (CSP) based on the Transportation Problem approach. The main flows of the algorithm are arranged in three steps. First we propose a heuristic algorithm of the greedy principle to obtain an initial feasible solution. Secondary we present a method of formulating CSP into a Modified Transportation Problem format. Lastly the procedures of network search to get the optimal solution are presented. This algorithm can be applied to the general GSP and also to most combinatorial problems like the Vehicle Routing Problems. The computational results show that the large size CSP's could be tackled.

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Program Family for Extended Pretty Printer

  • Ahn, Tae-Nam
    • Journal of the military operations research society of Korea
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    • v.10 no.1
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    • pp.65-86
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    • 1984
  • This thesis presents a design and partial implementation of a program family of extended pretty printers. Factors that influence the readability (perception) and understand ability (cognition) of computer programs are indentified, previous work is reviewed, and new solutions are suggested. Extensions to the previous pretty printer designs include a capability to selectively display levels of control of a program. In order to accommodate different computer languages and to allow for, several secondary functions, a family of pretty printers is designed. This design facilitates easy extension, contraction and modification.

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A Dual Problem and Duality Theorems for Average Shadow Prices in Mathematical Programming

  • Cho, Seong-Cheol
    • Journal of the Korean Operations Research and Management Science Society
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    • v.18 no.2
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    • pp.147-156
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    • 1993
  • Recently a new concept of shadow prices, called average shadow price, has been developed. This paper provides a dual problem and the corresponding duality theorems justifying this new shadow price. The general duality framework is used. As an important secondary result, a new reduced class of price function, the pp. h.-class, has been developed for the general duality theory. This should be distinguished from other known reductions achieved in some specific areas of mathematical programming, in that it sustains the strong duality property in all the mathematical programs. The new general dual problem suggested with this pp. h.-class provides, as an optimal solution, the average shadow prices.

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