• Journal of Korean Institute of Industrial Engineers
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• v.2 no.1
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• pp.85-92
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• 1976

In this paper, the employment planning model is developed which is a decision-making model for determining the optimum employment level with respect to varying net manpower requirement for each planing period such that total cost in a planning horizon is minimized. It is constructed as a nonlinear programming model and a dynamic programming model on the basis of studies in the areas of production smoothing and manpower scheduling. Costs for a planning period are categorized into regular wage cost, hiring cost, and overtime cost. The first is a linear function. The other two cost functions are of quadratic nature. The planning horizon of this planning model is intermediate range (five years) for which a fair planning accuracy can be guaranteed. The model considers learning period for each job class. It is simple and an optimum solution can be easily obtained by direct search techniques.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.4
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• pp.466-475
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• 1999

A backward Dynamic Programming(DP) model for the optimal facility replacement decision problem during a finite planning horizon is presented. Multiple alternative challengers to a current defender are considered. All facilities are assumed to have finite service lives. The objective of the DP model is to maximize the profit over a finite planning horizon. As for the cost elements, purchasing cost, maintenance costs and repair costs as well as salvage value are considered. The time to failure is assumed to follow a weibull distribution and the maximum likelihood estimation of Weibull parameters is used to evaluate the expected cost of repair. To evaluate the revenue, the rate of operation during a specified period is employed. The cash flow component of each challenger can vary independently according to the time of occurrence and the item can be extended easily. The effects of inflation and the time value of money are considered. The algorithm is illustrated with a numerical example. A MATLAB implementation of the model is used to identify the optimal sequence and timing of the replacement.

• Journal of the Korean Operations Research and Management Science Society
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• v.13 no.1
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• pp.10-23
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• 1988

This paper examines a deterministic, discrete-time, finite-horizon, production/distribution problem for a one-plant multi-retailer system. Production may occur at the plant in each time period. Customer demands at each retailer over a finite number of periods are known and must be met without backlogging. The plant as well as the retailers can serve as stocking points. The problem is to find a minimum-cost production/distribution schedule satisfying the known demands. We show that under a certain cost structure a nested policy is optimal, and present an efficient algorithm to find such an optimal policy. Planning horizon results and some computational saving schemes are also presented.

• Journal of the Korean Operations Research and Management Science Society
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• v.15 no.1
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• pp.83-97
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• 1990

We consider an insured who wishes to determine his optimal reporting strategy over a given planning horizon, when he has option of reporting of not reporting his at-fault accidents. Assuming that the premium in future period is continually adjusted by the insured's loss experience, the insured would not report every loss incurred. Rather, considering the benefits and costs of each decision, the insured may want to seek a way of optimizing his interests over the planning horizon. The situation is modeled as a dynamic programming problem. We consider an insured's discounted expected cost minimization problem, where the premium increase in future period is affected by the size of the current claim. More specifically, we examine two cases ; (1) the premium increase in the next is a linear function (a constant fraction) of the current claim size; (2) the premium increase in the next period is a concave function of the current claim size. In each case, we derive the insured's optimal reporting strategy.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.633-635
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• 1999

We design to the temperature control system based on Receding horizon control(RHC) with a terminal output weighting for stochastic state model. This system has a large time delay, a nonlinear temperature characteristics, a perturbation, a disturbance, etc. In this paper, we show that RHC can easily be applied to the system to track the desired temperature, since it takes the receding horizon strategy for both controller and filter.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.2
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• pp.102-113
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• 2004

This paper addresses the transportation planning that is based on genetic algorithm for determining transportation time and transportation amount of minimizing cost of distribution system. The vehicle routing of minimizing the transportation distance of vehicle is determined. A distribution system is consisted of a distribution center and many retailers. The model is assumed that the time horizon is discrete and finite, and the demand of retailers is dynamic and deterministic. Products are transported from distribution center to retailers according to transportation planning. Cost factors are the transportation cost and the inventory cost, which transportation cost is proportional to transportation distance of vehicle when products are transported from distribution center to retailers, and inventory cost is proportional to inventory amounts of retailers. Transportation time to retailers is represented as a genetic string. The encoding of the solutions into binary strings is presented, as well as the genetic operators used by the algorithm. A mathematical model is developed. Genetic algorithm procedure is suggested, and a illustrative example is shown to explain the procedure.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.3
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• pp.137-158
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• 1992

We study the Multiple Product Single Facility Stockout Avoidance Problem (SAP). That is the problem of determining, given initial inventories, whether there is a multiple product single facility production schedule that avoids stockouts over a given time horizon. The optimization version of the SAP where stockouts are pnelized linearly is also studied. We call this problem the Weighted Stockout Problem (WSP). Both problems are NP-hard in the strong sense. We develop Mixed Integer Linear Programming (MIP) formulations for both the SAP and the WSP. In addition, several heuristic algorithms are presented and performances are tested using computational experiments. We show that there exist polynomial algorithms for some special cases of the SAP and the WSP. We also present a method to phase into a target cyclic schedule for infinite horizon problems. These can be used as a practical scheduling tool for temporarily overloaded facilities or to reschedule production after a disruption.

• Journal of the military operations research society of Korea
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• v.10 no.1
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• pp.57-63
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• 1984

The 0-1 multi-period Knapsack problem (MPKP) has a horizon of m periods, each having a number of types of projects with values and weights. Subject to the requirement, the cummulative capacity of the problem in each period i cannot be exceeded by the total weight of the projects selected in period 1, 2, ..., i. It is a problem of selecting the projects in such a way that the total value in the knapsack through the horizon of m periods is maximized. A search algorithm is developed and tested in this paper. Search rules that avoid the search of redundant partial solutions are used in the algorithm. Using the property of MPKP, a surrogate constraint concerned with the most available requirement is used in the bounding technique.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.243-249
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• 2005

To improve the ride comfort and handling characteristics of a vehicle, an active suspension which is controlled by external actuators can be used. An active suspension can control the vertical acceleration of a vehicle and the tire deflection to achieve the desired suspension goal. For this purpose, Model Predictive Control (MPC) scheme is applied with the assumption that the preview information of the oncoming road disturbance is available. The predictive control approach uses the output prediction to forecast the output over a time horizon and determines the future control over the horizon by minimizing the performance index. The developed method is applied to a half car model of four degrees-of-freedom and numerical simulations show that the MPC controller improves noticeably the ride qualities and handling performance of a vehicle.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.472-477
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• 2009

This study was conducted to reclassify Bugog series based on the second edition of Soil Taxonomy : A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Morphological properties of typifying pedon of Bugog series were investigated and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Bugog series has strong brown (7.5YR 4/6) loam Ap horizon (0~22 cm), brown (7.5YR 4/4) clay loam BAt horizon (22~41 cm), strong brown (7.5YR 4/6) silty clay loam Bt1 horizon (41~59 cm), strong brown (7.5YR 4/6) silty clay loam Bt2 horizon (59~78 cm), brown (7.5YR 4/4) silty clay loam Btx1 horizon(78~90 cm), and brown (7.5YR 4/4) Btx2 horizon(90~160 cm). That occurs on swale foot slope in area of mainly granite gneiss, granite, and schist rock materials. The typifying pedon has an argillic horizon from a depth of 22 to more than 160 cm and a base saturation (sum of cations) of less than 35% at 75 cm below the upper boundary of the fragipan. That can be classified as Ultisol, not as Alfisol. The pedon has udic soil moisture regime, and can be classified as Udult. That has a fragipan with an upper boundary within 100 cm of the mineral soil surface, and keys out as Fragiudult. Also that meets the requirements of Typic Fragiudult. That has 18% to 35% clay at the particle-size control section, and has mesic soil temperature regime. Bugog series can be classified as fine silty, mixed, mesic family of Typic Fragiudults, not as fine loamy, mixed, mesic family of Typic Fragiudalfs.