• Title/Summary/Keyword: Supply Function Model

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Development of Intelligent ATP System Using Genetic Algorithm (유전 알고리듬을 적용한 지능형 ATP 시스템 개발)

  • Kim, Tai-Young
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.131-145
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    • 2010
  • The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

Short-term Forecasting of Power Demand based on AREA (AREA 활용 전력수요 단기 예측)

  • Kwon, S.H.;Oh, H.S.
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.39 no.1
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    • pp.25-30
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    • 2016
  • It is critical to forecast the maximum daily and monthly demand for power with as little error as possible for our industry and national economy. In general, long-term forecasting of power demand has been studied from both the consumer's perspective and an econometrics model in the form of a generalized linear model with predictors. Time series techniques are used for short-term forecasting with no predictors as predictors must be predicted prior to forecasting response variables and containing estimation errors during this process is inevitable. In previous researches, seasonal exponential smoothing method, SARMA (Seasonal Auto Regressive Moving Average) with consideration to weekly pattern Neuron-Fuzzy model, SVR (Support Vector Regression) model with predictors explored through machine learning, and K-means clustering technique in the various approaches have been applied to short-term power supply forecasting. In this paper, SARMA and intervention model are fitted to forecast the maximum power load daily, weekly, and monthly by using the empirical data from 2011 through 2013. $ARMA(2,\;1,\;2)(1,\;1,\;1)_7$ and $ARMA(0,\;1,\;1)(1,\;1,\;0)_{12}$ are fitted respectively to the daily and monthly power demand, but the weekly power demand is not fitted by AREA because of unit root series. In our fitted intervention model, the factors of long holidays, summer and winter are significant in the form of indicator function. The SARMA with MAPE (Mean Absolute Percentage Error) of 2.45% and intervention model with MAPE of 2.44% are more efficient than the present seasonal exponential smoothing with MAPE of about 4%. Although the dynamic repression model with the predictors of humidity, temperature, and seasonal dummies was applied to foretaste the daily power demand, it lead to a high MAPE of 3.5% even though it has estimation error of predictors.

Water Supply forecast Using Multiple ARMA Model Based on the Analysis of Water Consumption Mode with Wavelet Transform. (Wavelet Transform을 이용한 물수요량의 특성분석 및 다원 ARMA모형을 통한 물수요량예측)

  • Jo, Yong-Jun;Kim, Jong-Mun
    • Journal of Korea Water Resources Association
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    • v.31 no.3
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    • pp.317-326
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    • 1998
  • Water consumption characteristics on the northern part of Seoul were analyzed using wavelet transform with a base function of Coiflets 5. It turns out that long term evolution mode detected at 212 scale in 1995 was in a shape of hyperbolic tangent over the entire period due to the development of Sanggae resident site. Furthermore, there was seasonal water demand having something to do with economic cycle which reached its peak at the ends of June and December. The amount of this additional consumption was about $1,700\;\textrm{cm}^3/hr$ on June and $500\;\textrm{cm}^3/hr$ on December. It was also shown that the periods of energy containing sinusoidal component were 3.13 day, 33.33 hr, 23.98 hr and 12 hr, respectively, and the amplitude of 23.98 hr component was the most humongous. The components of relatively short frequency detected at $2^i$[i = 1,2,…12] scale were following Gaussian PDF. The most reliable predictive models are multiple AR[32,16,23] and ARMA[20, 16, 10, 23] which the input of temperature from the view point of minimized predictive error, mutual independence or residuals and the availableness of reliable meteorological data. The predicted values of water supply were quite consistent with the measured data which cast a possibility of the deployment of the predictive model developed in this study for the optimal management of water supply facilities.

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Flow Analysis around within Sump in a Pump Station using by the CFD (CFD에 의한 펌프장 Sump내 유동해석)

  • Roh, Hyung-Woon;Kim, Jae-Soo;Suh, Sang-Ho
    • 유체기계공업학회:학술대회논문집
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    • 2002.12a
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    • pp.89-94
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    • 2002
  • n general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

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An Inventory Management System usins Fuzzy Neural Network (퍼지 신경망을 이용한 재고관리 시스템)

  • 허철회;정환묵
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.12a
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    • pp.27-30
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    • 2001
  • A inventory management system of the manufacturing industry has a model of different kinds according to the objective and the situation. A inventory management system needs superior system technique in demand forecast, economical efficiency, reliability and application for stable supply of the finished goods, the raw materials and the parts. This paper proposes a demand forecast method based on fuzzy structured neural network, which uses min-operation and trapezoid membership function of fuzzy rules. So we can have an intelligent inventory management system for optimized decision-making of forecasting data with expert's opinion in fuzzy environment. This inventory management system used an intelligence agent and it could be adapted to asystemenvironmentchangeinorder.

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Optimal Inventory and Price Markdown Policy for a Two-Layer Market with Demand being Price and Time Dependent

  • Jeon, Seong-Hye;Sung, Chang-Sup
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2006.11a
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    • pp.142-146
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    • 2006
  • This paper considers a SCM issue concerned with an integrated problem of inventory control and dynamic pricing strategies when demands are price and time dependent. The associated price markdowns are conducted for inventory control in a two-layer market consisting of retailer and outlet as in fashion apparel market. The objective function consists of revenue terms (sales revenue and salvage value) and purchasing cost term. Specifically, decisions on price markdowns and order quantity are made to maximize total profit in the supply chain so as to have zero inventory level at the end of the sales horizon. To solve the proposed problem, a gradient method is applied, which shows an optimal decision on both the initial inventory level and the discount pricing policy. Sensitivity analysis is conducted on the demand parameters and the final comments on the practical use of the proposed model are presented.

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An Empirical Study on the Critical Success Factors of MRO e-marketplace (MRO e-marketplace의 성공 요인에 관한 탐색적 연구)

  • 김상수;하종태
    • The Journal of Information Technology and Database
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    • v.8 no.2
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    • pp.17-40
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    • 2001
  • The purpose of this study is to empirically identify the critical success factors of MRO e-marketplace. The research model presented in this study suggests that the success of MRO e-marketplace depends on environment of organization, type of product and service, and system of MRO e-marketplace. The major empirical findings of a survey of 38 firms in Korea are as follows: 1) The managers of firms have a deep concern on the effectiveness of MRO e-marketplace and are satisfied with the time saving provided by the transaction through MRO e-marketplace. 2) The variables affecting the success of MRO e-marketplace are classified into eight factors representing the characteristics of environment of organization, type of product and service, and system of MRO e-marketplace. 3) Among eight factors extracted from factor analysis, three factors are highly associated with the success of MRO e-marketplace. More specifically, the three factors, such as inside environment of company, capability of product supply, and basic function of MRO e-marketplace system, are the most Important factors affecting the success of MRO e-marketplace. The implications of the study are discussed and furlher research directions are proposed.

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An Inventory Management System Based on Intelligent Agents

  • Her, Chul-whoi;Chung, Hwan-mook
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.7
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    • pp.584-590
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    • 2001
  • An inventory management system of manufacturing industry has a model of different kinds according to the objective and the situation. An inventory management system needs superior system technique in demand forecast, economical efficiency, reliability and application for stable supply of the finished goods, the raw materials and the parts. This paper proposes a demand forecast method based on fuzzy structured neural network, which uses min-operation and trapezoid membership function of fuzzy rules. So we can construct an intelligent inventory management system that make optimized decision-making for forecasting data with expert s opinion in fuzzy environment. The inventory management system uses intelligence agent and it could be adapted to a system environment change in order.

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Analysis Technique on Collusive Bidding Incentives in a Competitive Generation Market (경쟁형 전력시장에서 입찰담합의 유인에 대한 분석 기법 연구)

  • Lee, Kwang-Ho
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.6
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    • pp.259-264
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    • 2006
  • This paper addresses the collusive bidding that functions as a potential obstacle to a fully competitive wholesale electricity market. Cooperative game is formulated and the equation of its Nash Equilibrium (NE) is derived on the basis of the supply function model. Gencos' willingness to selectively collude is expressed through a bargain theory. A Collusion Incentive Index(CII) for representing the willingness is defined through computing the Gencos' profits at NE. In order to keep the market non-cooperative, the market operator has to know the highest potentially collusive combination among the Gencos. Another index, which will be called the Collusion Monitoring Index(CMI), is suggested to detect the highest potential collusion and it is calculated using the marginal cost functions of the Gencos without any computation of NE. The effectiveness of CMI for detecting the highest potential collusion is verified through application on many test market cases.

Flow Analyses around Intake within Sump in a Pump Station (펌프장에서 Sump내 흡입구 주위의 유동해석)

  • Roh Hyung-Woon;Kim Jae-Soo;Suh Sang-Ho
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.597-600
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    • 2002
  • In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are Investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

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