• 대한산업공학회지
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• 제34권4호
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• pp.425-432
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• 2008

While the Vendor-Managed Inventory(VMI) is a convenient inventory replenishment policy for the customer company, the supplier usually bears the burden of higher inventory and urgent shipments to avoid shortage. Recently some manufacturers begin to fix the production schedule for the next few days (such as three days). Utilizing that information can improve the efficiency of the VMI. In this study, we present a myopic optimization model using a mixed inter programming; and a heuristics algorithm. We compare the performance of the two proposed methods with the existing (s, S) reorder policy. We consider the total cost as the sum of transportation cost and inventory cost at the customer's site. Numerical tests indicate that the two proposed methods significantly reduce the total cost over the (s, S) policy.

• 한국경영과학회지
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• 제9권2호
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• pp.15-22
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• 1984

A deterministic multiproduct, facility-in series multiperiod production planning model is analyzed, where each period demand for the product of a facility appear in a fixed proportion of that for the product of the immediately following facility. The model considers concave production and inventory costs, which can depend upon the production in different facilities. No backlogging is allowed. It is shown that the model is represented via a single source network, which facilitates development of efficient dynamic programming algorithms for computing the optimal production schedule.

• 대한산업공학회지
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• 제21권2호
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• pp.207-216
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• 1995

Constructing a distributed management system has its own advantages in addressing the issue of implementing a quick responsive management system in dynamically changing environment of enterprise. We suggest a basic scheduling methodology applicable to a distributed production management system. A new concept of "flexible schedule" is introduced as a tool to accommodate dynamically changing situations of job shops. Then a search technique (referred to as CSP-CBA search) is presented to obtain such a schedule for the job shop scheduling problem, which is converted into a constraint satisfaction problem(CSP), by using the constraint based analysis(CBA). This approach is tested on more than 100 test problems. The results show that the suggested approach required shorter CPU time and solved more problems in given time than another fixed schedule method.

• 수산경영론집
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• 제46권3호
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• pp.129-141
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• 2015

Because land based aquaculture is restricted by high investment per rearing volume and control cost, good management planning is important in Land-based aquaculture system case. In this paper master production planning was made to decide the number of rearing, production schedule and efficient allocation of water resources considering biological and economic condition. The purpose of this article is to build the mathematical decision making model that finds the value of decision variable to maximize profit under the constraints. Stocking and harvesting decisions that are made by master production planning are affected by the price system, feed cost, labour cost, power cost and investment cost. To solve the proposed mathematical model, heuristic search algorithm is proposed. The model Input variables are (1) the fish price (2) the fish growth rate (3) critical standing corp (4) labour cost (5) power cost (6) feed coefficient (7) fixed cost. The model outputs are (1) number of rearing fish (2) sales price (3) efficient allocation of water pool.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.272-273
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• 2014

Existing the free-form concrete segments (FCS) mold is produced by state of solid such as steel, wood, Styrofoam that can not be recycled. Using FCS mold result in delay on schedule and decrease of productivity because it consists of irregular curved variety and it requires more time than fixed mold. Thus, FCS mold should be developed which can reduce the costs and also it can be used as semipermanent. The aim of this study is to suggest of flexible mold production process for using the phase change materials(PCM). PCM is maintain that its solid state at low temperature but it changes phase to liquid state by heating. PCM is suitable material for flexible mold due to change of phase in relatively high temperature compare to other phase change materials such as water. Flexible mold is possible that reuse semi-permanently made by PCM. Thus, this study is proposed the process of flexible mold production for using the PCM. The study results will be used as the basic theory for studies on production and installation of FCS.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.985-993
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• 2017

Objective: The objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller's dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat. Methods: Two cohorts of 36 pigs each (initial body weight = $78.5{\pm}3.7kg$) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of $TiO_2$ as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential $p{\leq}0.001$) with the inclusion of phytase for all ingredients. Results: Basal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients. Conclusion: Variations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.