• Title/Summary/Keyword: Transportation-Inventory

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A Study on Estimation of CO2 Emission and Uncertainty in the Road Transportation Sector Using Distance Traveled : Focused on Passenger Cars (도로교통부문에서 주행거리를 이용한 CO2 배출량 및 불확도 산정에 관한 연구: 승용차 중심으로)

  • Park, Woong Won;Park, Chun Gun;Kim, Eungcheol
    • Journal of Korean Society of Transportation
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    • v.32 no.6
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    • pp.694-702
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    • 2014
  • Since Greenhouse Gas Inventory & Research Center (GIR) of Korea was founded in 2010, the annual greenhouse gas inventory reports, one of the collections of GIR's major affairs, have been published from 2012. In the reports many items related to greenhouse gas emission quantities are included, but among them uncertainty values are replaced to basic values which IPCC guideline suggests. Even though IPCC guideline suggests the equations of each Tier level in details, the guideline recommends developing nation's own methodology on uncertainty which is closely related to statistical problems such as the estimation of a probability density function or Monte carlo methods. In the road transportation sector the emissions have been calculated by Tier 1 but the uncertainties have not been reported. This study introduce a bootstrap technique and Monte carlo method to estimates annual emission quantity and uncertainty, given activity data and emission factors such as annual traveled distances, fuel efficiencies and emission coefficients.

The Optimal Ordering Policy for the Generalized Two-Stage Inventory System (일반화된 2단계 재고체계에서의 최적주문정책)

  • 정남기;차동원
    • Journal of the Korean Operations Research and Management Science Society
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    • v.4 no.1
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    • pp.25-31
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    • 1979
  • We consider the optimal ordering policy for a single-product two-stage inventory system where the main assumptions are as follows: (i) constant continuous demand only at stage 2, (ii) constant input (production) rate at stage 1, (iii) instantaneous delivery (transportation) from stage 1 to stage 2, (iv) backlogging is allowed only at stage 2, (v) an infinite planning horizon. Costs considered are ordering and linear holding costs at both stages, and linear shortage cost only at stages 2. By solving 9 different case problems, we have observed the general from of the optimal ordering policies for our model which minimizes the total cost per unit time. It is noticeable from this observation that the questionable but more often than not adopted assumption by many authors in determining the optimal potimal policy for multistage inventory systems, that the ordering (lot) sizes at each stage remain constant thruout the planning horizon, is not valid.

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A Design for Optimal Models of Inventory-Distribution System with Back-Ordered Case (부재고를 갖는 재고.수송시스템의 최적모형설계)

  • 우태희;조남호
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.20 no.43
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    • pp.25-36
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    • 1997
  • The purpose of this paper is to structure a new integrated model that can minimize the total cost for the transportation and inventory systems between m origin points, where origin i has a supply of a commodity, such as distribution centers or warehouses, and n destination points, where destination j requires the commodity. In this case, demands of the destination points are assumed random variables which have a known probability distribution. We will find optimal distribution centers which transport the commodity to the destination points and suggest optimal inventory policy to the selected distribution center which find the optimal pair $$ and safety stock level that minimize total cost with back-ordered case. This new model is formulated as a 0-1 nonlinear integer programming problem. To solve the problem, this paper proposes heuristic computational procedures and program and provides numerical examples.

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Determination of Number and Location of Central Warehouses by Heuristics (휴리스틱을 이용한 중앙창고의 수와 위치 결정)

  • Lee, Dong-Ju;Hwang, In-Keuk;Park, Dong-Jin
    • IE interfaces
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    • v.19 no.1
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    • pp.78-85
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    • 2006
  • A centralized inventory system provides a number of stores with cost reduction, information sharing. In this paper, transportation costs are included in the inventory model. To build centralized warehouses, two things should be considered: how many warehouses are required and where these are located. The objective of this paper is to develop efficient heuristics to determine the location and the number of central warehouses by minimizing total costs. Throughout some computational experiments, the results of the heuristics are compared with an optimal solution.

Preliminary Estimation of National Emission Inventory for the Unintentionally Produced Polychlorinated Biphenyls (국내 부산물 다염화비페닐(PCBs) 배출량 예비 평가)

  • Kim Kyoung-Mi;Cho Kyu-Tak;Lee Jee-Yoon;Lee Jee-Eun;Lee Dong-Soo
    • Environmental Analysis Health and Toxicology
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    • v.19 no.2
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    • pp.227-233
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    • 2004
  • The main objectives of this study were to identify from literature review the potential sources and to provide a preliminary national emission inventory for the unintentionally produced polychlorinated biphenyls (PCBs) (i.e., by - product PCBs). In Korea, fuel combustion, waste combustion, thermal industrial processes, and transportation were identified as potential sources of by -product PCB s. According to the availability of the emission factors and/or activity data, emission inventory could be assessed only for fuel combustion, waste combustion, steel industry, non-ferrous industry, and non-metallurgical industry. The total national emission of by-product PCBs was estimated to be 1087kg for the year 2000. The preliminary estimation further indicated that the steel manufacturing was the single dominant emission category, contributing 93% to the total emission. Of the steel manufacturing processes, the contribution of the electric arc furnace was about 80% of the total emission. Due to high uncertainty associated with both the emission factors and activity statistics, the emission estimates in this study are likely to contain significant errors. However, the results of the present work could serve the first step toward future efforts to establish national source and emission inventories of by-product PCBs.

An inventory analysis on greenhouse gas emissions from bulk carrier and oil tanker (벌크선박과 유조선의 온실 가스 배출 인벤토리 분석)

  • Im, Nam-Kyun;Yi, Sung-Ryong
    • Journal of Navigation and Port Research
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    • v.34 no.3
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    • pp.189-194
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    • 2010
  • 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 out dynamically in various industrial fields. This study was carried out to examine the application of LCA to ships and was focused on the inventory analysis on global warming gas from merchant cargo ships. Two merchant cargo ships 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 global warming gas being exhausted to transport 1 ton of each cargo per 1 nautical mile.

The Use of Particle Swarm Optimization for Order Allocation Under Multiple Capacitated Sourcing and Quantity Discounts

  • Ting, Ching-Jung;Tsai, Chi-Yang;Yeh, Li-Wen
    • Industrial Engineering and Management Systems
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    • v.6 no.2
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    • pp.136-145
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    • 2007
  • The selection of suppliers and the determination of order quantities to be placed with those suppliers are important decisions in a supply chain. In this research, a non-linear mixed integer programming model is presented to select suppliers and determine the order quantities. The model considers the purchasing cost which takes into account quantity discount, the cost of transportation, the fixed cost for establishing suppliers, the cost for holding inventory, and the cost of receiving poor quality parts. The capacity constraints for suppliers, quality and lead-time requirements for the parts are also taken into account in the model. Since the purchasing cost, which is a decreasing step function of order quantities, introduces discontinuities to the non-linear objective function, it is not easy to employ traditional optimization methods. Thus, a heuristic algorithm, called particle swarm optimization (PSO), is used to find the (near) optimal solution. However, PSO usually generates initial solutions randomly. To improve the PSO solution quality, a heuristic procedure is proposed to find an initial solution based on the average unit cost including transportation, purchasing, inventory, and poor quality part cost. The results show that PSO with the proposed initial solution heuristic provides better solutions than those with PSO algorithm only.

A Simple Method for Solving Type-2 and Type-4 Fuzzy Transportation Problems

  • Senthil Kumar, P.
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.4
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    • pp.225-237
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    • 2016
  • In conventional transportation problem (TP), all the parameters are always certain. But, many of the real life situations in industry or organization, the parameters (supply, demand and cost) of the TP are not precise which are imprecise in nature in different factors like the market condition, variations in rates of diesel, traffic jams, weather in hilly areas, capacity of men and machine, long power cut, labourer's over time work, unexpected failures in machine, seasonal changes and many more. To counter these problems, depending on the nature of the parameters, the TP is classified into two categories namely type-2 and type-4 fuzzy transportation problems (FTPs) under uncertain environment and formulates the problem and utilizes the trapezoidal fuzzy number (TrFN) to solve the TP. The existing ranking procedure of Liou and Wang (1992) is used to transform the type-2 and type-4 FTPs into a crisp one so that the conventional method may be applied to solve the TP. Moreover, the solution procedure differs from TP to type-2 and type-4 FTPs in allocation step only. Therefore a simple and efficient method denoted by PSK (P. Senthil Kumar) method is proposed to obtain an optimal solution in terms of TrFNs. From this fuzzy solution, the decision maker (DM) can decide the level of acceptance for the transportation cost or profit. Thus, the major applications of fuzzy set theory are widely used in areas such as inventory control, communication network, aggregate planning, employment scheduling, and personnel assignment and so on.

A Study on Database System for Hostorical Booking of Korean Railroad (한국철도의 예약실적 데이터베이스 시스템에 관한 연구)

  • Oh, Seog-Moon;Hwang, Jong-Gyu;Hyeon, Seung-Ho;Kim, Yong-Gyu;Lee, Jong-Woo;Kim, Young-Hoon;Hong, Soon-Heum;Park, Jong-Bin
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.371-374
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    • 1998
  • The construction of the transportation history database system is to serve the scheduling and seat inventory controling. Recently, lots of countries have been faced with the advance era because of the new railway transportation system, like the high speed railway and/or magnetic levitation vehicle system. This can be reasonably translated as those of operators are willing to provide the more various and high quality schedule to the customer. Those operators these ideas make possible to forecast that scheduling process is going to be complicated more and more. The seat inventory control, so to speak Yield Management System(YMS), goes a long way to improve the total passenger revenue at the railway business. The YMS forecasts the number of the last reservation value(DCP# END) and recommends the optimal values on the seat sales. The history database system contains infra-data(ie, train, seat, sales) that will be the foundation of scheduling and seat inventory control application programs. The development of the application programs are reserved to the next step. The database system is installed on the pc platform (IBM compatible), using the DB2(RDBMS). And at next step, the platform and DBMS will be considered whether they can meet the users' requirement or not.

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On Fleet Sizing and Distribution Policy of Transportation Equipments in Hub-and-Spoke Network (방사형 물류체계에서 수송장비의 보유대수 결정과 분배정책)

  • Seo, Sun-Keun;Lee, Byung-Ho
    • IE interfaces
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    • v.11 no.1
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    • pp.55-66
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    • 1998
  • Fleet sizing and distribution of empty equipments are two of the most critical problems in managing transportation system. This paper develops a cost model for sizing a fleet and establishing decentralized redistribution polices of empty equipments by building from inventory theory of multi-echelon system in hub-and-spoke network. An analytical approach to determine control variables of redistribution policies in each terminal and fleet size of the transportation system is proposed and its results are validated by simulation model. Numerical experiments are conducted with respect to parameters of the model and test results for assumptions of the model are discussed.

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