• Title, Summary, Keyword: demand uncertainty

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Study on the Effects of the Interactions between Demand and Supply Uncertainties on Supply Chain Costs (수요 불확실성과 공급 불확실성의 상호 작용이 공급 사슬 비용에 미치는 효과에 대한 연구)

  • Park Sangwook;Kim Soo-Wook
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.3
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    • pp.81-93
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    • 2005
  • This paper models supply chain uncertainties in the dynamic Newsboy Problem context. The system consists of one supplier and one retailer who place an order to the supplier every period. Demand uncertainty is modeled as stochastic period demand, and supply uncertainty as the uncertainty in quantities delivered by the supplier. The supplier delivers exactly the amount ordered by the retailer with probability of $\beta$ and the amount minus K with probability of $(1-\beta)$ We formulate the problem as a dynamic programming problem and derive the first-order optimality condition. Through a numerical study, we measure the extent to which the cost decrease due to the reduction in supply uncertainty depends on the level of demand uncertainty. One of the most important findings In this paper is that this cost decrease is relatively small if demand uncertainty is kept high, and vice versa. We also backup this numerical result by analyzing the distribution of ending Inventory under the supply and demand uncertainties.

Assessing the Effects of Supply Uncertainty on Inventory-Related Costs (공급업자의 공급불확실성이 재고관리 비용에 미치는 효과에 관한 연구)

  • 박상욱
    • Journal of the Korean Operations Research and Management Science Society
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    • v.26 no.3
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    • pp.105-117
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    • 2001
  • This paper models supply uncertainty in the dynamic Newsboy problem context. The system consists of one supplier and one retailer who places an order to the supplier every period to meet stochastic demand. Supply uncertainty is modeled as the uncertainty in quantities delivered by the supplier. That is, the supplier delivers exactly the amount ordered by the retailer with probability of $\beta$ and the amount minus K with probability of (1-$\beta$). We formulate the problem as a dynamic programming problem and prove that retailer’s optimal replenishment policy is a stationary base-stock policy. Through a numerical study, we found that the cost increase due to supply uncertainty is significant and that the costs increase more rapidly as supply uncertainty increases. We also identified the effects of various system parameters. One of the interesting results is that as retailer’s demand uncertainty, the other uncertainty in our model, increases, the cost increase due to supply uncertainty becomes less significant.

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Uncertainty of Water Supply in Agricultural Reservoirs Considering the Climate Change (미래 기후변화에 따른 농업용 저수지 용수공급의 불확실성)

  • Nam, Won-Ho;Hong, Eun-Mi;Choi, Jin-Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.2
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    • pp.11-23
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    • 2014
  • The impact and adaption on agricultural water resources considering climate change is significant for reservoirs. The change in rainfall patterns and hydrologic factors due to climate change increases the uncertainty of agricultural water supply and demand. The quantitative evaluation method of uncertainty based on agricultural water resource management under future climate conditions is a major concern. Therefore, it is necessary to improve the vulnerability management technique for agricultural water supply based on a probabilistic and stochastic risk evaluation theory. The objective of this study was to analyse the uncertainty of water resources under future climate change using probability distribution function of water supply in agricultural reservoir and demand in irrigation district. The uncertainty of future water resources in agricultural reservoirs was estimated using the time-specific analysis of histograms and probability distributions parameter, for example the location and the scale parameter. According to the uncertainty analysis, the future agricultural water supply and demand in reservoir tends to increase the uncertainty by the low consistency of the results. Thus, it is recommended to prepare a resonable decision making on water supply strategies in terms of using climate change scenarios that reflect different future development conditions.

Impact of uncertain natural vibration period on quantile of seismic demand

  • Hong, H.P.;Wang, S.S.;Kwan, A.K.H.
    • Structural Engineering and Mechanics
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    • v.28 no.4
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    • pp.357-372
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    • 2008
  • This study investigates effect of uncertainty in natural vibration period on the seismic demand. It is shown that since this uncertainty affects the acceleration and displacement responses differently, two ratios, one relating peak acceleration responses and the other relating the peak displacement responses, are not equal and both must be employed in evaluating and defining the critical seismic demand. The evaluation of the ratios is carried out using more than 200 strong ground motion records. The results suggest that the uncertainty in the natural vibration period impacts significantly the statistics of the ratios relating the peak responses. By using the statistics of the ratios, a procedure and sets of empirical equations are developed for estimating the probability consistent seismic demand for both linear and nonlinear systems.

Supply Chain Coordination for Perishable Products under Yield and Demand Uncertainty: A Simulation Approach (수요와 수율의 불확실성을 고려한 공급망 조정)

  • Kim, Jin Min;Choi, Suk Bong
    • Journal of the Korean Society for Quality Management
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    • v.46 no.4
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    • pp.959-972
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    • 2018
  • Purpose: This study developed a simulation model that incorporates the uncertainty of demand and yield to obtain optimized results for supply chain coordination within environmental constraints. The objective of this study is to examine whether yield management for perishable products can achieve the goal of supply chain coordination between a single buyer and a single supplier under a variety of environmental conditions. Methods: We investigated the efficiency of a revenue-sharing contract and a wholesale price contract by considering demand and yield uncertainty, profit maximizing ratio, and success ratio. The implications for environmental variation were derived through a comparative analysis between the wholesale price contract and the revenue-sharing contract. We performed Monte Carlo simulations to give us the results of an optimized supply chain within the environments defined by the experimental factors and parameters. Results: We found that a revised revenue-sharing contracting model was more efficient than the wholesale price contract model and allowed all members of the supply chain to achieve higher profits. First, as the demand variation (${\sigma}$) increased, the profit of the total supply chain increased. Second, as the revenue-sharing ratio (${\Phi}$) increased, the profits of the manufacturer gradually decreased, while the profits of the retailer gradually increased, and this change was linear. Third, as the quality of yield increased, the profits of suppliers appear to increased. At last, success rate was expressed as the profit increased in the revenue-sharing contract compared to the profit increase in the wholesale price contract. Conclusion: The managerial implications of the simulation findings are: (1) a strategic approach to demand and yield uncertainty helps in efficient resource utilization and improved supply chain performance, (2) a revenue-sharing contract amplifies the effect of yield uncertainty, and (3) revised revenue-sharing contracts fetch more profits for both buyers and suppliers in the supply chain.

Strategic Foreign Direct Investment in Developing Countries under Demand Uncertainty: Commitment vs. Flexibility

  • Hyun, Hea-Jung
    • East Asian Economic Review
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    • v.16 no.1
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    • pp.25-66
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    • 2012
  • The paper analyzes the effect of expected future demand on the investment decisions of multinational enterprises. In particular, I explore the issue of the timing of switching between exporting and FDI in the host developing country and explicitly incorporate the firm's attitude toward risk in the model. The model demonstrates that the optimal time for switching to FDI depends on the expected future demand and the degree of its uncertainty.

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Power Distribution System Planning with Demand Uncertainty Consideration

  • Wattanasophon, Sirichai;Eua-arporn, Bundhit
    • Journal of Electrical Engineering and Technology
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    • v.3 no.1
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    • pp.20-28
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    • 2008
  • This paper proposes a method for solving distribution system planning problems taking into account demand uncertainty and geographical information. The proposed method can automatically select appropriate location and size of a substation, routing of feeders, and appropriate sizes of conductors while satisfying constraints, e.g. voltage drop and thermal limit. The demand uncertainty representing load growth is modeled by fuzzy numbers. Feeder routing is determined with consideration of existing infrastructure, e.g. streets and canals. The method integrates planner's experience and process optimization to achieve an appropriate practical solution. The proposed method has been tested with an actual distribution system, from which the results indicate that it can provide satisfactory plans.

A Study on the Uncertainty of Additional Generating Capacity in Long Term Electricity Plan (전력수급기본계획에서 발전소 준공 불확실성에 대한 고찰)

  • Kim, C.S.;Rhee, C.H.
    • Proceedings of the KIEE Conference
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    • pp.843-845
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    • 2005
  • The uncertainty of long term electricity plan consists of the uncertainty of demand forecast and additional generating capacity. Demand forecast is clearly improved the accuracy than the past through improving forecasting methods. However, the uncertainty of additional generating capacity is increased due to the change of market environment. In an operation by a sole utility, additional generating capacity would be possible by the regulation of government. Currently the generation companies have spined off from KEPCO and some IPPs participate the electricity market. It increases the uncertainty due to weakened regulation. Also the environment movement by NGOs and occurrence of civil affairs cause the increase of uncertainty. This research would analyze the current situation on the uncertainty of additional generating capacity and construction delays. Furthermore this research would present the plan to reflecting it in long term electricity plan.

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A Study on the Production Environment of Apparel Manufacture (의류제조업체의 생산환경에 관한 연구)

  • Sun-Hee Lee;Mi-A Suh
    • The Research Journal of the Costume Culture
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    • v.8 no.1
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    • pp.30-39
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    • 2000
  • The purpose of this study were to 1) identify types and levels of production environments, 2) classify apparel manufacturers based on production environments and 3) investigate relationship between characteristics of apparel manufacturers and production environment. Apparel manufacturer's characteristics included product line and the number of employees. For this study, the questionnaires were administered to 215 apparel manufacturers in seoul and Kyung-gi region from Feb. to Mar. 1998. Employing a sample of 201, data were analyzed by factor analysis, descriptive statistics, cluster analysis, cluster analysis, discriminant Analysis, and multivariate analysis of variance. The following are the results of this study : 1. The production environment was identified as three types such as complexity of product environment, uncertainty of demand/supply environment and uncertainty of worker environment. 2. Based on three types of the production environment, apparel manufacturers were classified into stable group, uncertain group and complicated group. 3. With respect to product line, men's wear manufacturers were lied the most high complexity of product environment, casual wear and knit wear were lied the most frequently uncertainty of worker environment. With respect to the number employees, apparel manufacturers comprising 50∼99 employees were lied the most high complexity of product environment, while those comprising 100∼299 employees the most high demand/supply environment.

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Investigation and Empirical Validation of Industry Uncertainty Risk Factors Impacting on Bankruptcy Risk of the Firm (기업부도위험에 영향을 미치는 산업 불확실성 위험요인의 탐색과 실증 분석)

  • Han, Hyun-Soo;Park, Keun-Young
    • Korean Management Science Review
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    • v.33 no.3
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    • pp.105-117
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    • 2016
  • In this paper, we present empirical testing result to examine the validity of inbound supply and outbound demand risk factors in the sense of early predicting the firm's bankruptcy risk level. The risk factors are drawn from industry uncertainty attributes categorized as uncertainties of input market (inbound supply), and product market (outbound demand). On the basis of input-output table, industry level inbound and outbound sectors are identified to formalize supply chain structures, relevant inbound and outbound uncertainty attributes and corresponding risk factors. Subsequently, publicly available macro-economic indicators are used to appropriately quantify these risk factors. Total 68 industry level bankruptcy risk forecasting results are presented with the average R-square scores of between 53.4% and 37.1% with varying time lag. The findings offers useful insights to incorporate supply chain risk to the body of firm's bankruptcy risk level prediction literature.