• Title/Summary/Keyword: Transportation-Inventory

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A Note on Production and Shipment Lot Sizing in a Vendor-Buyer Supply Chain with Transportation Cost (생산자-구매자 공급망에서 운송비용을 고려한 생산 및 출하량 결정)

  • Kim, Chang-Hyun;Kim, Tae-Bok
    • Journal of the Korean Operations Research and Management Science Society
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    • v.33 no.4
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    • pp.53-61
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    • 2008
  • Recently, Ertogral et al.[2] suggested two models considering the transportation cost based on single-vendor single-buyer integrated production-inventory problem. Although their problem-solving algorithm guarantees solutions obtained are optimal, a limitation is revealed that its performance can be inefficient due to complete enumeration search in a certain range. In this paper, a more efficient algorithm in finding optimal solutions is suggested for the same problem suggested by Ertogral et at.[2]. Numerical examples are presented for illustrative purpose.

Impacts of Delivery Vehicle Routing on Different Inventory Strategies and Network Configurations (재고전략 및 네트워크 구성에 따른 배송차량의 운영특성 연구)

  • Won, Min-Su;Gang, Gyeong-U
    • Journal of Korean Society of Transportation
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    • v.28 no.5
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    • pp.91-106
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    • 2010
  • Recently, interest in supply chain management is rising along with the increasing oil prices and traffic congestion. In particular, people started studying the issue, but realized that advantageous strategies for suppliers and retailers are not always advantageous to a carrier. Therefore, in this study the atuhors set up a simulation scenario to understand delivery vehicle routing problems under various inventory policies, namely Economic Order Quantity (EOQ) and Periodic Order Quantity (POQ) and network configurations. First, the authors made a virtual supply chain. Then they analyzed characteristics of delivery vehicle routing under various inventory policies (EOQ and POQ) and network configurations. As a result, the POQ inventory policy decreases the number of vehicles, the number of drivers, and the service time of vehicles. Also, the centralized network increases the load factor of vehicles and decreases the service time of vehicles. In other words, the centralized network and the POQ inventory policy are better for the carrier. These results show a savings of 15,556,806 won ($13,389.10) in a month: a reduction of 17%.

A Study on A Methodology for Centralized Warehouse Problem Considering Multi-item and Budget Constraint (다품종 예산제약을 고려한 중앙창고문제 해결방법론에 대한 연구)

  • Lee, Dongju
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.35 no.4
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    • pp.126-132
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    • 2012
  • This paper deals with a centralized warehouse problem with multi-item and capacity constraint. The objective of this paper is to decide the number and location of centralized warehouses and determineorder quantity (Q), reorder point (r) of each centralized warehouse to minimize holding, setup, penalty, and transportation costs. Each centralized warehouse uses continuous review inventory policy and its budget is limited. A SA (Simulated Annealing) approach is developed and its performance is tested by using some computational experiments.

A Study of Determining the Economical Shortage Ratio for Safety Stock - With Emphasis on the Rolling Stock Part - (안전재고의 경제적 품질률 결정에 관한 연구 철도차량부품을 중심으로)

  • 이근희;이승구
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.11 no.17
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    • pp.47-54
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    • 1988
  • Korean National Railroad(K.N.R) playing a important role in land transportation gives us many problems to solve considering proper management of National Budget and development of the state of operation by maintaining train parts rationally as public services. According this study is to show inventory provision system for deciding the safety inventory level as the better rational method. Bibliography for this study is limited to only three kinds of seven brakes-shoe which is produced by T workshop in Korean National Railroad. To reduce the holding cost coming from the want of the stock and shortage cost of the stock expected. This study is to present a ratio of shortage on the stock permitted for the last definite period and the demand result forecast per month.

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A Study on $CO_2$ Emissions with the Carbody Material of Electric Motor Unit (EMU) using Life Cycle Inventory Analysis (LCIA) (전과정목록 분석을 이용한 전동차의 구체 재질에 따른 $CO_2$ 배출량에 관한 연구)

  • Kim, Yong-Ki;Chun, Yoon-Young;Lee, Jae-Young
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.1123-1125
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    • 2006
  • As Kyoto protocol has been effective in 2005, the reduction of $CO_2$ emission is a global urgent problem. In Korea, the $CO_2$ emission of transportation increases continuously, which can be solved partially by the use of railroad. Therefore, it is necessary to calculate exactly the $CO_2$ emission of railroad through life cycle approach. In this study, the $CO_2$ emission of electric motor unit (EMU) was evaluated with its carboy material using life cycle inventory analysis (LCIA). Among the life cycles of EMU, $CO_2$ emission was the highest in the running phase. As the total weight of EMU was lowered, $CO_2$ emission was reduced. In conclusion, the light-weighting of EMU can reduce $CO_2$ emission efficiently.

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An Estimation of Age-, Power-, and Type-Specific Emission Inventories for Construction Equipments Using Improved Methodologies and Emission Factors (배출계수 개발 및 배출량 산정 체계 고도화를 통한 건설기계의 연식, 출력 및 기종별 대기오염물질 배출량 산정)

  • Jin, Hyungah;Lee, Taewoo;Park, Hana;Son, Jihwan;Kim, Sangkyun;Hong, Jihyung;Jeon, Sangzin;Kim, Jeongsoo;Choi, Kwangho
    • Journal of Korean Society for Atmospheric Environment
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    • v.30 no.6
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    • pp.555-568
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    • 2014
  • The construction equipment is one of the major sources for hazardous air pollutants in Korea, and the its management has been of great concern recently. The objective of this study was to estimate each contribution of emission of construction equipments according to their production year, electric power consumption and type. To achieve this goal, we developed pollutant emission factors for the machineries manufactured after 2009, which are excluded from the present framework of Korean air pollutants inventory, CAPSS. More than 800 data obtained from emission investigations were utilized for the estimation. Compared with the previous estimation, the scheme used this study was modified to incorporate new emission factors as well as to include the corresponding activity data. Such improvement allow us to gain more detailed emission informations which are better characterized by specifications of construction equipments. The total amount of pollutants emitted from construction equipments in 2011 were estimated as 126.8, 7.0, 58.3, and 17.0 kton for $NO_x$, PM, CO, and VOC, respectively. The estimation results indicate that the increase in the emission of equipments is significantly related to their age and power consumption. The emissions of the older ones manufactured from 1992~1996 were estimated to be the contribution ranged from 23.7% to 26.8%, whereas the newer ones (2009~2011) showed the attributions of 11.3~21.5%. In addition, the results show that the emission of each equipment was increased with the increase in the electric power consumption of engine, probably due to their average output power. Among the nine types of machinery compared, excavators and forklifts were investigated to contribute relatively higher emissions in the level of 39.8~44.0% and 32.0~34.2%, respectively.

The inventory analysis on exhaust gas from training ships for ship's LCA study (선박 전과정평가를 위한 실습선 배기가스 인벤토리 분석)

  • Im, Nam-Kyun;Jo, Ho-Jin
    • Journal of Navigation and Port Research
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    • v.32 no.1
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    • pp.29-35
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    • 2008
  • As the seriousness of the global environment is gaining our attention recently, studies on application of LCA(Life Cycle Assessment) to ship are being carried dynamically in various industry fields. However domestic study on LCA was not carried out in various fields. This study was carried out to examine the application of LCA to ship and was focused on the ship operation inventory analysis especially in life cycle assessment. Two training ships of Mokpo maritime university were adopted as ship models. Actual voyage data of at last several years was used to analysis the ship's exhaust gas inventory. The analysis shows how many weight of gas being exhaused per 1 gross tonnage and per 1 trainee in the training ships.

Development of logistics decision models - review and research direction - (물류의사결정을 위한 계량모형의 현황과 발전방향)

  • 문상원
    • Korean Management Science Review
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    • v.11 no.2
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    • pp.99-131
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    • 1994
  • This paper shows the direction in which logistics modellers should make their effort by examining the gap between desirable characteristics which logistics decision models should possess and deficiencies from which existing models suffer. For this purpose, we(1) categorized logistics models into facility planning, inventory management and transportation/delivery planning models, (2) carried out a wide survey of theoretical and industry models within each category and (3) assessed recent development of integrated logistics models.

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Development of decision supporting package for the design of a physical distribution system (물류시스템 설계를 위한 의사결정지원 패키지의 개발)

  • 송성헌;양병학
    • Korean Management Science Review
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    • v.10 no.2
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    • pp.79-91
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    • 1993
  • Strategic decisions related to the design of a physical distribution system can be classified into three basic components : facility location, transportation, inventory decisions. In this research the interdependence of those decisions are expressed in a mathematical model such that the total relevant cost of the system is minimized. We suggested a heuristic technique for solving the model. In broad terms, our solution technique combines a heuristic method for determining which candidate DCs to open and an exact method for minimizing costs given a set of open DCs. And we also developed a decision supporting package for the design of a physical distribution system.

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A Study on Dynamic Lot Sizing Problem with Random Demand (확률적 수요를 갖는 단일설비 다종제품의 동적 생산계획에 관한 연구)

  • Kim, Chang Hyun
    • Journal of Korean Institute of Industrial Engineers
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    • v.31 no.3
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    • pp.194-200
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    • 2005
  • A stochastic dynamic lot sizing problem for multi-item is suggested in the case that the distribution of the cumulative demand is known over finite planning horizons and all unsatisfied demand is fully backlogged. Each item is produced simultaneously at a variable ratio of input resources employed whenever setup is incurred. A dynamic programming algorithm is proposed to find the optimal production policy, which resembles the Wagner-Whitin algorithm for the deterministic case problem but with some additional feasibility constraints.