• Journal of Korean Society on Water Environment
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• v.34 no.3
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• pp.270-284
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• 2018

Paldang is a river reservoir located in the Midwest of Korea, with a water volume of $244{\cdot}10^6m^3$ and a water surface area of $36.5km^2$. It has eutrophied since the construction of a dam at the end of 1973, and the phosphorus concentration has decreased since 2001. Average hydraulic residence time of the Paldang reservoir is about 10 days during the spring season and 5.6 days as an annual level. The hydraulics and water quality of the reservoir can differ greatly, both temporally and spatially. For the spring period (March to May) in 2001 ~ 2017, the reservoir mean total phosphorus concentration calculated from the budget model based on a plug-flow system (PF) and a continuous stirred-tank reaction system (CSTR) was 13 % higher and 10 % lower than the observed concentration, respectively. A composite flow system (CF) was devised by assuming that the transition zone was plug flow, and that the lacustrine zone was completely mixed. The mean concentration calculated from the model based on CF was not skewed from the observed concentration, and showed just 6 % error. The retention coefficient of the phosphorus derived from the CF was 0.30, which was less than those of the natural lakes abroad or river reservoirs in Korea. The apparent settling velocity of total phosphorus was estimated to be $93m\;yr^{-1}$, which was 6 ~ 9 times higher than those of foreign natural lakes. Assuming CF, the critical load line for the total phosphorus concentration showed a hyperbolic relation to the hydraulic load in the Paldang reservoir. This is different from the previously known straight critical load line. The trophic state of the Paldang reservoir has recently been estimated to be mesotrophic based on the critical-load curve of the phosphorus budget model developed in this study. Although there is no theoretical error in the newly developed budget model, it is necessary to verify the validity of the portion below the inflection point of the critical-load curve afterwards.

• IE interfaces
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• v.14 no.3
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• pp.286-295
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• 2001

This paper addresses the problem of determining the proper level of concurrent spare parts(CSP) for a system consisting of multi-item parts under an available budget constraint. Initial provisioning of spare parts plays a major role in the acquisition of a new equipment system. Therefore, the proper level of spare parts should be on hand to maintain the availability of the system. This paper proposes a new CSP model and solution procedure that determines the proper level of spare parts satisfying the item priority and simultaneously available budget constraint.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.15-25
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• 2004

For the effective operation of irrigation reservoirs, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. In this study, the flood effective analysis system was developed through the integration of long-term water budget analysis model, GIS-based HEC-HMS model and HEC-RAS model. The system structure consists of long-term water budget model using modified TANK theory, flood runoff and flood effects analysis model using HEC-GeoHMS, HEC-HMS and HEC-RAS models. The flood effects analysis system simulated the flood runoff from the upstream, downstream flood and long-term runoff of the watershed using the observed data collected from 1998 to 2002 of Seongju dam. The simulated results were reasonably good compared with the observed data. The optimal management method of the reservoir during the whole season is suggested in this study, and the flood analysis system can be a useful tool to evaluate a reservoir operation quantitatively for the mitigation of flood damages of reservoir basin.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.6-11
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• 2013

In this study, the effect of damping and elastic nature on the control performance of a safety budget-industrial accident rate model in Korea is examined first. The effectiveness of such dynamic model in establishing safety policies is shown with a simple proportional-integral(PI) feedback control mechanism. Control performance of the safety system model is explained in view of maximizing the effect of IAPF and minimizing the absolute amount of IAFP. Control performance is then evaluated and proved to be effective to prevent and reduce the industrial accidents. Implications in feedback control of a safety system model suggested to optimization of safety policies are also explored. Without proper restructuring of the safety system, it would not be possible to hit the target industrial accident rate. Even if the control objective is met, the amount of industrial accident prevention fund required to reduce the industrial accident rate from the current level to the target level would be far beyond the social consensus.

• Journal of the Korea Society of Computer and Information
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• v.18 no.7
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• pp.165-174
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• 2013

Recently, many universities in Korea have been faced with critical crisis such as the decrease in the number of freshmen, the pressure for tuition cuts, M&A between universities and so on. Nobody has expected that universities will have this kind of difficulties. The universities are making attempts to innovate the quality of education to secure high level of education and to meet social needs to overcome these internal and external environment of crisis. For this innovation, the universities have sought to reduce the budget as well as conducted the self-evaluation to figure out their relative positions annually. Innovations cannot have having the limitation without education funds. Budget spent in universities have influences directly or indirectly on the structural improvement of the finance and on the growth of universities. The purpose of this study is to explore the decision-making method to find the optimal budget allocation so as to minimize the execution budget and to maximize the management evaluation by taking the advantage to analyse the relationship between the evaluation and the budget. Therefore, in this paper, we implement the development of the mathematical model for the University Evaluation and Budget Allocation Optimization in the form of the linear programming.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.561-563
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• 2010

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.33-43
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• 2004

A carbon budget model was constructed and analyzed for the Bangjukpo surf zone ecosystem in southern Korea by using the NETWRK. The model consists of 11 living and 1 non-living groups. Using boxes and arrows, a topological map was created to depict biomasses of each group and exchange rates between them. The system includes primary producers of phytoplankton and benthic algae, primary consumers of particle feeding zooplankton, carnivorous zooplankton, meiobenthos, malacostracans and bivalves, and top consumers of detrivorous, omnivorous, carnivorous and piscivorous fishes. The surf zone ecosystem was analyzed by means of network analysis, showing total system throughput of $574\;gCm^{-2}yr^{-1},$ development capacity of $1,876\;gCm^{-2}yr^{-1},$ ascendancy value of $768\;gCm^{-2}yr^{-1},$ Finn cycling index of $4.4\%$ and internal relative ascendancy of $27\%.$ These results were compared with similar data from other systems.

• Management & Information Systems Review
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• v.13
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• pp.127-140
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• 2003

Although there have been continual researches in the project scheduling problems since 1960s, the main interest has been how to improve the efficiency of a single project. The minimization problem of the project completion time given a preassigned budget might be an example. This kind of the problem is important, but estimating of the proper budget for a project may also be very important. This research deals with the budget allocation problem for the multiple project. This research is unique in that the project scheduling techniques are used for the budgeting problem. Therefore, this research may be used as a strategic decision model for the multiple large projects in public sector.

• Journal of the military operations research society of Korea
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• v.23 no.1
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• pp.63-75
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• 1997

This study is concerned with a few models for optimal requirement level of CSP by improving and adjusting the existing models to determine CSP items and quantity as follows. First, by building a model with a objective function of the operating level and constrains of budget, quantity and items of CSP are simultaneously determined. Second, we removed some steps to improve initial solution by using a constraint of usable budget level. Third, we demonstrated a model to be applied with real operating situation by combining two models of Lee(1994) and above. Lastly, by assuming a failure probability distribution is a binomial distribution, the better solution can be obtained. Some facts with necessity of policy improvement were raised as follows: (1) necessity of improvement of the CSP acquisition system, (2) in case of the same kind, permission of diversion in order to execute budget effectively, (3) getting accurate failure rate.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.39-60
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• 1995

In this paper, an integration of stochastic dynamic programming (SDP), integer goal programming (IGP) and analytic hierarchy process (AHP) is proposed to handle multiobjective-multicriteria sequential decision making problems under uncertainty inherent in R & D investment planning. SDP has its capability to handle problems which are sequential and stochastic. In the SDP model, the probabilities of the funding levels in any time period are generated using a subjective model which employs functional relationships among interrelated parameters, scenarios of future budget availability and subjective inputs elicited from a group of decision makers. The SDP model primarily yields an optimal investment planning policy considering the possibility that actual funding received may be less than anticipated one and thus the projects being selected under the anticipated budget would be interrupted. IGP is used to handle the multiobjective issues such as tradoff between economic benefit and technology accumulation level. Other managerial concerns related to the determination of the optimal project portifolio within each stage of the SDP model. including project selection, project scheduling and annual budget allocation are also determined by the IGP. AHP is proposed for generating scenario-based transformation probabilities under budgetary uncertainty and for quantifying the environmental risk to be considered.