• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.131-138
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• 2009

This paper considers a coordinated scheduling problem between multi-suppliers and an manufacture. When the supplier has insufficient inventory to meet the manufacture's order, the supplier may use the expedited production and the expedited transportation. In this case, we consider a scheduling problem to minimize the total cost of suppliers and manufacture. We suggest an population management genetic algorithm with local search and crossover (GALPC). By the computational experiments comparing with general genetic algorithm, the objective value of GALPC is reduced by 8% and the calculation time of GALPC is reduced by 70%.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.2
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• pp.173-179
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• 2005

This paper presents an extended EMQ model which determines an optimal production quantity for a single stage production system when defective items are stochastically produced in the production process and they are re-processed in the rework process to convert them into non-defectives. Through the mathematical modeling, an optimal solution minimizing the average cost per unit time and minimum average cost as well as some properties are derived. It can be shown that each of the existing models is a special case of the proposed model under some conditions. Numerical experiment is carried out to examine the behavior of the proposed model and support properties derived.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.4
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• pp.103-110
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• 2007

The facility location in designing a supply chain network is an important decision problem that gives form, structure, and shape to the entire supply chain system. Location problems involve determining the location, number, and size of the facilities to be used. The optimization of these location decisions requires careful attention to the inherent trade-offs among service time, inventory costs, facility cost, transportation costs. This paper presents a strategy that provides the best locations of distribution centers using GIS(Geographical Information System) assuming the limitation of delivery time. To get the best strategy of the location of distribution centers, we use the new loss functions as a penalty when the delivery time is violated

• Journal of Korean Institute of Industrial Engineers
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• v.1 no.2
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• pp.39-49
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• 1975

The problem treated is that of locating distribution centers(depot) in a network, so as to minimize the total cost which is the sum of transportation cost, (from factory to centers and from centers to demand points), construction cost, inventory cost and traffic increasing cost. This problem is mathematically an integer program and a non-linear model. This study avoids various inefficient aspects, which many studies have shown, by introducing a matrix notation, node and link function. An algorithm, for determining the optimal location of distribution center which has zone in which demand points are located at some node of a network, is presented. Finally this paper describes a numerical example and discusses its results.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.322-328
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• 2007

Highly standardized products are suitable for automated purchasing using electronic commerce technology, where the price becomes the most important factor. Suppliers can change the prices dynamically based on the inventory level and market situation in order to maximize the sales and profit. In the virtual marketplace where multiple customers purchase multiple standardized products from multiple suppliers repetitively, customers can purchase the required amount of each item as a dynamic bidding by allocating purchase orders to the suppliers based on the current price. Customers need a method to quickly determine the optimal allocation of orders to the suppliers using the dynamically changing data to minimize the total cost. We present a LP model which minimizes the sum of the total price plus transportation cost for this problem. Simulation results using random data show meaningful reduction of the total cost.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.440-449
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• 2007

This paper describes the efforts in developing several versions of bridge management system (BMS) in Taiwan. There were several versions of stand-alone BMS developed in Taiwan prior to the Ji-Ji earthquake that occurred in year 1999. Since many bridges were seriously damaged by this earthquake, the Ministry of Transportation and Communication determined to develop a nationwide BMS to have a better by control on the status of bridge maintenance. Implemented in year 2000, the Taiwan Bridge Management system (T-BMS) is now the dominating and mandatory system used by all the government agencies that are responsible for bridge maintenance. Having more then 25,000 bridges in its inventory, T-BMS has thousands of logins per month to update data in the relevant database. The experiences and difficulties of using such a nationwide bridge management system are discussed. Finally, future plans for BMS development are also proposed in this paper.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.580-602
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• 2011

Volatile organic compound (VOC) emissions in the 2007 CAPSS (Clean Air Protection Supporting System) emissions inventory are chemically speciated for the SAPRC99 (Statewide Air Pollution Research Center 99) mechanism, following the Source Classification Code (SCC) matching method to borrow the U.S.EPA's chemical speciation profiles. CMAQ simulations with High-order Direct Decoupled Method (HDDM) are in turn applied to evaluate uncertainty in the method by comparing the simulated model VOC species to the observations in the Seoul Metropolitan Area (SMA) for a 2007 June episode. Simulations under-predicted ALK1 to ALK4 in SAPRC99 by a factor of 2 to 5 and over-predicted ALK5 by a factor of 7.5 while ARO1, ARO2, OLE1, and ethylene (ETH) are comparable to the observations, showing relative difference by 10 to 30%. OLE2 emissions are roughly 4 times overestimated. Emission rates for individual VOC model species are revised referring to the ratio of simulated to observed concentrations. Impact of the VOC emission changes on the overall ozone prediction was insignificant for the days of which 1-hr maximum ozone are lower than 100 ppb. However, simulations showed ozone difference by 5 to 10 ppb when high ozone above 120 ppb was observed in the vicinity of Seoul. This result suggests that evaluations on individual model VOC emissions be necessary to lead ozone control plans to the right direction. Moreover, the simulated ratios of ARO1 and ARO2 to $NO_x$ are roughly 50% lower than the observed ones, which imply that adjustment in $NO_x$ and VOC emission rates may be required to mimic the real VOC/$NO_x$ condition over the area.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.223-230
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• 2011

According to EMEP/EEA Emission Inventory Guidebook, the emissions produced by vehicle in cold start phase should be calculated differently compared to hot start phase. In this study, considering this driving cycle, more appropriate procedures for estimating Environmental Benefits was suggested. Using Tier 3 standard, all links within the impact area were included in estimating emissions. Traffic volume and travel distance were analyzed using EMME/3 software. For application of the procedures in this study, the case study was carried out with real transportation project. As a result, the Environment-Benefits increased by 30%. If the methodology suggested in this study is applied to feasibility study it will help to activate the investment of the environment-friendly modes like railway in the future.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.293-299
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• 2004

Traffic represents one of the largest sources of primary air pollutants in urban area. As a consequence, numerous abatement strategies are being pursued to decrease the ambient concentration of pollutants. A characteristics of most of the these strategies is a requirement for accurate data on both the quantity and spatial distribution of emissions to air in the form of an atmospheric emission inventory database. In the case of traffic pollution, such an inventory must be compiled using activity statistics and emission factors for vehicle types. The majority of inventories are compiled using passive data from either surveys or transportation models and by their very nature tend to be out-of-date by the time they are compiled. The study of current trends is towards integrating urban traffic control systems and assessments of the environmental effects of motor vehicles. In this study, a model of vehicle emission calculation by using real-time traffic data was studied. Traffic data, which are required on a street-by-street basis, is obtained from induction loops of traffic control system. It is possible that characteristics of hourly air pollutants emission rates is obtained from hourly traffic volume and speed. An emission rates model is allocated with a high resolution space by using geographic information system (GIS). Vehicle emission model was developed with a high resolution spatial, gridded and hourly emission rates.

• KIEAE Journal
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• v.13 no.5
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• pp.103-110
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• 2013

This study aims to calculate the $CO_2$ emissions by the properties of construction waste to establish a LCI DB of construction waste generated at the disuse stage. The $CO_2$ emissions from apartment houses was calculated by calculating the energy consumptions by treatment steps to calculate the $CO_2$ emissions by the treatment steps of construction waste. As a result of analyzing the $CO_2$ emissions from a total of 27 complexes, maximum 46,791g-$CO_2/m^2$, minimum 34,893g-$CO_2/m^2$ and average 38,713g-$CO_2/m^2$ were generated, and were varied by the quantity of construction waste in general, but were affected by the transportation distance in case of transportation steps as well. As a result of analyzing the $CO_2$ emissions by the properties of construction waste, average 19,815.50g-$CO_2/m^2$ was generated, the highest, from the example complex at the demolition stage in case of construction wastes, and 1.72g-$CO_2/m^2$ was generated, the lowest, during reclamation. In case of combustible waste, average 11,495.63g-$CO_2/m^2$ was generated, the highest, from the example complex during incineration of wastes, and 21.48g-$CO_2/m^2$ was generated, the lowest, at the waste transportation stage. In case of noncombustible waste, average 522.43g-$CO_2/m^2$ was generated, the highest, from the example complex at the demolition stage, and 1.07g-$CO_2/m^2$ was generated, the lowest, at the transportation stage. In case of other construction wastes, average 645.42g-$CO_2/m^2$ was generated, the highest, from the example complex at the demolition stage, and 47.38g-$CO_2/m^2$ was generated, the lowest, at the middle treatment stage.