• 제목/요약/키워드: Cost approach

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A Design for Integrated Logistics System with Inventory Control and Transportation Planning Problem (재고와 수송계획문제를 고려한 통합물류시스템 설계)

  • 우태희;조남호
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.21 no.48
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    • pp.37-52
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    • 1998
  • In many distribution systems important cost reductions and/or service improvements may be achieved by adopting an efficient inventory policy and proper selection of facilities. These efficiency improvements and service enhancements clearly require an integrated approach towards various logistical planning functions. The areas of inventory control and transportation planning need to be closely coordinated. The purpose of this paper is to construct an integrated model that can minimize the total cost of the transportation and inventory systems between multiple origin and destination points, where in origin point i has the supply of commodities and in destination point j requires the commodities. In this case, demands of the destination points are assumed random variables which have a known probability distribution. Using the lot-size reorder-point policy and the safety stock level that minimize total cost we find optimal distribution centers which transport the commodities to the destination points and suggest an optimal inventory policy to the selected distribution center. We also show if a demand greater than one unit will occur at a particular time, we describe the approximate optional replenishment policy from computational results of this lot-size reorder-point policy. This model is formulated as a 0-1 nonlinear integer programming problem. To solve the problem, this paper proposes heuristic computational procedures and a computer program with UNIX C language. In the usefulness review, we show the meaning and validity of the proposed model and exhibit the results of a comparison between our approach and the traditional approach, respectively.

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Economic Analysis by Cost Estimation and Externality Classification to Agricultural Water Supply (논 농업용수의 외부효과 구분과 비용산정에 따른 경제성 분석)

  • Kim, Hae-Do;Hur, Seung-Oh;Jo, Jin-Hun;Na, Min-Chul
    • KCID journal
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    • v.17 no.2
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    • pp.3-16
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    • 2010
  • The subject of externality of agricultural water supply has been discussed in the OECD AC ( Organization for Economic Cooperation and Development Agriculture Committee) while argued between monsoon Asian developing countries and the agricultural product export nations (Australia, EU, etc). It argued that a 'positive' approach to multifunctionality views agriculture as an economic activity with multiple, interconnected outputs or effects, and a 'normative' approach interprets multifunctionality in terms of the multiple roles assigned to agriculture. and the agricultural product export nations insisted 'negative' approach to externality of agricultural water supply like causing water pollution. So, in this study, define the externalities (positive, negative and economic, environmental) in terms of the agricultural water supply and calculate benefit and cost each the externalities by cost estimation. As results, BC is calculated to 1.28 which means that it is more economical to agricultural water supply and shows that although the negative exernalities comes out while supply the agricultural water, it still more valuable to supply the agricultural water.

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Development of an uncertainty quantification approach with reduced computational cost for seismic fragility assessment of cable-stayed bridges

  • Akhoondzade-Noghabi, Vahid;Bargi, Khosrow
    • Earthquakes and Structures
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    • v.23 no.4
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    • pp.385-401
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    • 2022
  • Uncertainty quantification is the most important challenge in seismic fragility assessment of structures. The precision increment of the quantification method leads to reliable results but at the same time increases the computational costs and the latter will be so undesirable in cases such as reliability-based design optimization which includes numerous probabilistic seismic analyses. Accordingly, the authors' effort has been put on the development and validation of an approach that has reduced computational cost in seismic fragility assessment. In this regard, it is necessary to apply the appropriate methods for consideration of two categories of uncertainties consisting of uncertainties related to the ground motions and structural characteristics, separately. Also, cable-stayed bridges have been specifically selected because as a result of their complexity and the according time-consuming seismic analyses, reducing the computations corresponding to their fragility analyses is worthy of studying. To achieve this, the fragility assessment of three case studies is performed based on existing and proposed approaches, and a comparative study on the efficiency in the estimation of seismic responses. For this purpose, statistical validation is conducted on the seismic demand and fragility resulting from the mentioned approaches, and through a comprehensive interpretation, sufficient arguments for the acceptable errors of the proposed approach are presented. Finally, this study concludes that the combination of the Capacity Spectrum Method (CSM) and Uniform Design Sampling (UDS) in advanced proposed forms can provide adequate accuracy in seismic fragility estimation at a significantly reduced computational cost.

Market-Based Transmission Expansion Planning Under Uncertainty in Bids by Fuzzy Assessment

  • Kamyab, Gholam-Reza;Fotuhi-Firuzabad, Mahmood;Rashidinejad, Masoud
    • Journal of Electrical Engineering and Technology
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    • v.7 no.4
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    • pp.468-479
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    • 2012
  • In this paper, by a simple example it is shown that existing market-based criteria alone cannot completely and correctly evaluate the transmission network expansion from market view. However criteria congestion cost (CC) and social welfare (SW) together are able to correctly evaluate transmission network from market view and so they are adopted for the market-based transmission expansion planning. To simply indicate the limits of CC and SW social welfare percentage (SWP) and congestion cost percentage (CCP) are defined. To consider uncertainty in bids of market producers and consumers, and also indeterminacy in the acceptable boundaries of the SWP and CCP and their priorities, fuzzy assessment approach is used. In this approach, appropriate fuzzy sets and a fuzzy rule base are provided to evaluate the acceptability of an expansion plan. Then, the least-investment cost plan, which is acceptable in all probable scenarios, is searched. The proposed method is applied to an 8-bus system.

An Optimal Scheduling Method based upon the Lower Bound Cost Estimation (하한비용 추정에 바탕을 둔 최적 스케쥴링기법)

  • 엄성용;전주식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.28A no.12
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    • pp.73-87
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    • 1991
  • This paper presents a new approach to the scheduling problem in the high level synthesis. In this approach, iterative rescheduling processes starting with ASAP(As Soon As Possible) scheduling result are performed in a branch-and-bound manner so to arrive at the scheduling result of the lowest hardware cost under the given timing constraint. At each iteration step, only the selected nodes are considered for rescheduling, and the lower bound cost estimation is performed to avoid the unnecessary attempts to search for an optimal result. This branch-and-bound method turns out to be effective in pruning the search space, and thus reducing run time considerably in many cases.

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Stochastic Programming Approach to Scheduling Elective Surgeries and the Effects of Newsvendor Ratio on Operating Room Utilization (추계적 계획법을 이용한 수술실 예약 모델과 Newsvendor 비율의 자원 효율성에 대한 영향 분석)

  • Min, Dai-Ki
    • Korean Management Science Review
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    • v.28 no.2
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    • pp.17-29
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    • 2011
  • The purpose of this paper is to schedule elective surgery patients using a stochastic programming approach and to illustrate how operating room utilization behaves when a decision-maker varies costs associated with utilization. Because of the uncertainty in surgery durations, the underage and overage costs that a decision-maker considers plays an important role in allocating surgery cases into available operating room capacity. We formulate the problem as a stochastic mixed integer programming and propose a sampling-based approximation method for a computational purpose. Newsvendor model is employed to explain the results from numerical experiments that are conducted with the actual data from a hospital. The results show that the operating room utilization is more sensitive when the unit overtime cost is relatively larger than the unit cost for underutilized time.

A Design of $H_{\infty}$ Adaptive controller ($H_{\infty}$ 적응 제어기의 설계)

  • Park, Seung-Kyu;An, Ho-Kyun;Jang, Woo-Young
    • Proceedings of the KIEE Conference
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    • 1997.07b
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    • pp.679-681
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    • 1997
  • A $H_{\infty}$ adaptive controller is designed by using polynomial approach. The $H_{\infty}$ robust controllers for adaptive system were designed by Grimble. But they did not minimize the mixed sensitivity ra cost function which is the re sum of weighted sensitivity and complementary sensitivity terms Moreover pole placement is dependent of cost function. In this paper, the mixed sensitivity re cost function is minimized by employing the Youla parameterization and polynomial approach at the same time. And pole plaement is independent of weighting function.

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A Study on the Optimal Investment Method for Distribution Systems Interconnected with Dispersed Generations (분산전원이 연계된 배전계통의 최적 설비투자 방안에 관한 연구)

  • Rho, Dae-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.12
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    • pp.2179-2185
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    • 2008
  • This paper deals with the optimal investment method for distribution facilities, based on the analytical approach for the reliability assessment in distribution systems interconnected with new dispersed generations. The existing approach can estimate the expected reliability performance of distribution systems by a direct assessment of the configuration of the systems using the reliability indexes such as NDP(Non-Delivery Power) and NDE(Non-Delivery Energy). The indexes can only consider the number and configuration of the load, but can not consider the characteristics of the load which is the one of the most important factor in the investment cost for the distribution systems. Therefore, this paper presents the new performance indexes for the investment of the distribution facilities considering both the expected interruption cost for the load section and the operation characteristics of dispersed generations. The results from a case study show that the proposed methods can be a practical tool for the voltage management in distribution systems including dispersed sources.

A Benefit-Cost Analysis on the DSM Programs (DSM 프로그램의 비용효과 분석)

  • 오영진;김발호;박종배
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.9
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    • pp.535-541
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    • 2003
  • Demand Side Management (DSM) activities have been designed to encourage customers to modify their patterns of electricity consumption including the timing and level of electricity demand. The role of DSM has been more and more important in the point of social energy utilization on the limited resources. The objectives of DSM are generally related to load reductions and generation cost savings. This paper presents an approach to B/C analysis to evaluate the impact of DSM programs especially on the strategic conservation and the load management programs. The proposed approach embedding the existing B/C analyses is applicable to the new electricity market. Case studies show the B/C ratio and the avoided cost due to the impact of DSM programs.

Parallel and Sequential Implementation to Minimize the Time for Data Transmission Using Steiner Trees

  • Anand, V.;Sairam, N.
    • Journal of Information Processing Systems
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    • v.13 no.1
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    • pp.104-113
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    • 2017
  • In this paper, we present an approach to transmit data from the source to the destination through a minimal path (least-cost path) in a computer network of n nodes. The motivation behind our approach is to address the problem of finding a minimal path between the source and destination. From the work we have studied, we found that a Steiner tree with bounded Steiner vertices offers a good solution. A novel algorithm to construct a Steiner tree with vertices and bounded Steiner vertices is proposed in this paper. The algorithm finds a path from each source to each destination at a minimum cost and minimum number of Steiner vertices. We propose both the sequential and parallel versions. We also conducted a comparative study of sequential and parallel versions based on time complexity, which proved that parallel implementation is more efficient than sequential.