• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.415-419
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• 2013

To mitigate forest fire damage, it is needed to concentrate suppression resources on the fire having a high probability to become large in the initial stage. The objective of this study is to develop the large fire judgement model which can estimate large fire possibility index between the fire size and the related factors such as weather, terrain, and fuel. The results of logistic regression equation indicated that temperature, wind speed, continuous drought days, slope variance, forest area were related to the large fire possibility positively but elevation has negative relationship. This model may help decision-making about size of suppression resources, local residents evacuation and suppression priority.

• Magazine of the Korean Society of Agricultural Engineers
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• v.29 no.3
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• pp.125-137
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• 1987

The purpose of this paper is to examine some difficulties in water management of agricultural reservoirs in Korea, for there are approximately more than 15,000 reservoirs which are now being utilized for the purpose of irrigation, along with the much amount of expenses and labors to be invested against droughts and floods periodically occurred. Recently, the effective use of water resources in the agricultural reservoirs with a single purpose, is becomming multiple according to the alterable environment of water use. Therefore, the task to allocate agricultural water rationally and economically must be solved for the multiple use of agricultural reservoirs. On the basis of the above statement, this study aims at suggesting the rational method of water management by introducing an optimal technique to allocate the water in an existing agricultural reservoir rationally, for the sake of maximizing the economic effect. To achieve this objective, a reservoir, called "0-Bongje" as a sample of the case study, is selected for an agricultural water development proiect of medium scale. As a model for the optimum allocation of water in the multi-purpose use of reservoirs a linear programming model is developed and analyzed. As a result, findings of the study are as follows : First, a linear programing model is developed for the optimum allocation of water in the multi-purpose use of agricultural reservoirs. By adopting the model in the case of reservoir called "O-Bongje," the optimum solution for such various objects as irrigation area, the amount of domestic water supply, the size of power generation, and the size of reservoir storage, etc., can be obtained. Second, by comparing the net benefits in each object under the changing condition of inflow into the reservoir, the factors which can most affect the yearly total net benefit can be drawn, and they are in the order of the amount of domestic water supply, irrigation area, and power generation. Third, the sensitivity analysis for the decision variable of irrigation which may have a first priority among the objects indicate that the effective method of water management can be rapidly suggested in accordance with a condition under the decreasing area of irrigation. Fourth, in the case of decision making on the water allocation policy in an existing multi-purpose reservoir, the rapid comparison of numerous alternatives can be possible by adopting the linear programming model. Besides, as the resources can be analyed in connection with various activities, it can be concluded that the linear programing model developed in this study is more quantitative than the traditional methods of analysis. Fifth, all the possible constraint equations, in using a linear programming model for adopting a water allocation problem in the agricultural reservoirs, are presented, and the method of analysis is also suggested in this study. Finally, as the linear programming model in this study is found comprehensive, the model can be adopted in any different kind of conditions of agricultural reservoirs for the purpose of analyzing optimum water allocation, if the economic and technical coefficients are known, and the decision variable is changed in accordance with the changing condition of irrigation area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.154-163
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• 2015

This study is based on deductions from analysis of historical changes in hydrographic surveys, the problems with the existing system in Korea and analysis of the literature, including foreign cases. Using these criteria, we created and administered a survey of marine professionals of Korea, and based on the results, established an order of priority for hydrographic surveys, as follows: changes in the seabed, quantities of marine traffic, existing performance data from hydrographic survey, consumer's demand, marine accidents, conservation of oceanic environment, and natural resources. The study also deduced, based on a survey of experts, the relative importance ranking of the major ports in South Korea and suggests policy implications and a priority decision model to conduct future hydrographic surveys in a more scientific and systematic way.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.207-217
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• 2004

Our government is interested in the rehabilitation for the old sewer rather than the construction of a new sewer system. However, the research work on the sewer rehabilitation is not sufficient as much as the interest on the rehabilitation is increased. There are some research works for the determination of rehabilitation time by the genetic algorithm in Korea and foreign countries. However, the previous studies have considered the simple elements for the determination of the rehabilitation time and so the complex decision-making according to the degree of sewer superannuation has not been performed. Therefore, in this study, we estimate the capacity and Ⅰ/Ⅰ of sewer and determine the priority of the optimal rehabilitation for each outfall within the draining system. Also we develop the optimal rehabilitation decision making system for the cost estimation of optimal rehabilitation using the genetic algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.31-39
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• 2009

This paper shows prioritization process for equipment investment plans considering reliability indices and economical efficiency. To decide prioritization of distribution investment projects, we made a distribution system model using system configuration, it's component and load information and designed several investment alternatives to improve reliability of present system. Lastly, we proposed a evaluation model of economical efficiency assessment on distribution investment alternative projects. To analyze influence by reliability and economical efficiency, we produced economical effects with applying time-varying failure rate of KEPCO's main equipments of distribution system and interruption cost of electric power affected by investment. Finally, in order to insure the validity of this proposed methodology, we compared investment prioritization by economical evaluation with that of real investment alternatives of KEPCO's branch office. In conclusion, this paper shows what and how to interpret the reliability effects of distribution system investments into financial indicators beneficial for power utilities's managers to make decision on the perspective of corporate value.

• Journal of the Korean Institute of Navigation
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• v.12 no.2
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• pp.43-55
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• 1988

The amount of cargoes and fishery production have increased continuously during the last decade due to the great growth of the Korean economy. These increasements have made our coastal traffic congested, and the future coastal traffic is also expected to increase considerably. The increased traffic can be a cause of large sea pollution as well a s greater sea casualties us as properties and human lives, which could result in a big national loss. In order to prevent the sea casualties and promote the safety of coastal traffic, the Vessel Traffic Management System (VTMS) along the Korean coastal waterway is inevitably introduced. But, the precise evaluation is necessary required prior to the implementation of VTMS because this system necessitates a huge amount of budgets. This paper aims to propose the model of evaluation process, but the evaluation as to the urgency of establishment is not only very complicated and fuzzy but also affected by the subjectivity of human. Therefore, fuzzy integral is adopted as the mathematical model of evaluation in which decision-maker can intervence by making decision considering the calculated membership-function. Four aspects, namely, the frequency of sea-casualities, the traffic volume, the frequency fuzzy day, and the complexity of waterway are selected as the item of evaluation, and the fuzzy measure are applied to the evaluation of 8 candidated regions such as the adjacent area to the port Inchen, Kunsan, Mokpo, Wando, Yosu, Pusan, Pohang, Donghae. As a result of evaluation, the priority as to the candidated regions is obtained, and the following prior execution regions, namely, the adjacent area to the port Pusan, Yosu, Mokpo & Wando are selected by considering the present situation, but, in the long run, the VTMS should be executed in the whole coast of the nation, through the cost-effectiveness analysis.

• The Journal of Bigdata
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• v.5 no.2
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• pp.155-170
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• 2020

The purpose of this study was to apply machine learning techniques (Decision Tree, Random Forest, XGBoost) to data from the 4th~6th year of the Seoul Education Longitudinal Study to find the factors predicting the career maturity of middle school students in Seoul city. In order to evaluate the machine learning application result, the performance of the model according to the indicators was checked. In addition, the model was analyzed using the XGBoostExplainer package, and R and R Studio tools were used for this study. As a result, there was a slight difference in the ranking of variable importance by each model, but the rankings were high in 'Achievement goal awareness', 'Creativity', 'Self-concept', 'Relationship with parents and children', and 'Resilience'. In addition, using the XGBoostExplainer package, it was found that the factors that protect and deteriorate career maturity by panel and 'Achievement goal awareness' is the top priority factor for predicting career maturity. Based on the results of this study, it was suggested that a comparative study of machine learning and variable selection methods and a comparative study of each cohort of the Seoul Education Termination Study should be conducted.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.767-790
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• 2009

Setting up a priorityfor an embedded system is greatly significant because a release plan at the early stage of product developments can properly be established through right decision making procedures based on the priorities. For instance, both dependencies among requirements and the aspects of product developers should be considered into the priorities to improve the embedded system. Especially, trade-offs among the requirements, which are quite different depending on H/W and S/W architecture styles they use, should be acknowledged without exception. However, the selection process on the priority has hitherto been fairly systematic in the existing environment where hardware and software are not being considered at once. Therefore, this paper suggests an dependency and aspect-based model and process for the requirements of the priority. For this, the paper analyzes the trade-offs between the requirements depending on the disparate Architecture styles of H/W and S/W, and it also reflects the viewpoints of the developers. For thelast thing, the model and process suggested will be applied to the case of the development of both cell phones and cameras to gain authenticity and reliability. In conclusion, the danger occurring when the release plan is constructed can be minimized by screening the priorities that optimizes the embedded system more explicitly.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.163-168
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• 2014

In this paper, when photovoltaic systems are connected to distribution system, most effective capacity and location of PV system are studied considering customer interruption costs of power distribution system. The reliability model of PV system considering the duration of sunshine, the model of time-varying load and Roy Billinton test system (bus2 model) are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability and customer interruption costs for residential, general, industrial, and educational customer is evaluated.

• Journal of Technology Innovation
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• v.6 no.2
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• pp.159-177
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• 1998

Although each company is trying to develop an economic analysis model with its own particular style or format, the appropriate method is not yet developed because there are many problems to be solved such as uncertainity of outcomes and intangible benefits of technology. The purpose of tris paper therefore is to suggest an economic analysis methodology, which reflects the complexity and the risk of R&D investment, through a case study on the development of a superconductor fault current limiter. A self-developed Monte Carlo simulation program utilized as a main tool in this paper was very useful for risk analysis of R&D investment which could not be solved in the previous DCF(Discounted Cash Flow) model. We also introduce learning effect to consider the intangible benefits such as Know-How obtained from R&D execution. The expected value and its probability distribution for R&D investment can be obtained by combining the Monte Carlo method with the decision tree approach. This result is helpful in judging the priority and the resource-allocation of R&D projects. It is however necessary to develop more precise model for quantifying the technology stock and the simulation program using the continuous probability distribution in expected values to improve the reliability of economic analysis on R&D projects.