• Environmental and Resource Economics Review
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• v.26 no.4
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• pp.499-517
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• 2017

The purpose of this article is to show profit margin hedging can be an optimal strategy in crude oil purchasing. This study theoretically analyzes profit margin hedging strategy is optimal in crude oil purchasing using expected target utility function and conducts simulations to show if the profit margin hedging is profitable. In addition, this study tests existence of mean reversion of crude oil futures prices to confirm the theory that profit margin hedging is more profitable than other strategies, such as always hedging or buying at expiration with spot price, if futures prices are mean reverting. The simulation results show that the expected utility of profit margin hedging higher than other strategies. Although we cannot find any evidence that crude oil futures prices follow mean reverting process, we can conclude that profit margin hedging can be optimal strategy in crude oil purchasing based on theoretical proof and simulation results.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.590-599
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• 2018

As a basic information to implement the fire plan that dominates multiple targets effectively under the battle environment with limited resources, such a process is mandatory that gives a priority order to a target with the high level of threat by quantitatively computing the threat level of an individual target through the analysis on the target. However, the study has still remained in the initial level on an evaluation algorithm for the threat level of the ground target. Considering this fact, the present paper proposes the evaluation algorithm for the threat by multiple ground targets. The proposed algorithm has a core point to consider the type of target and protected asset to implement the computation of proximity; set the additional value based on the weights indicating the significance of weapon and protected asset; and compute the threat level of a target that considers the characteristics of the target. The evaluation and verification of performances have been implemented through the simulation and visualization of an algorithm proposed in the present paper. From the performance result, as the proposed algorithm has been able to perform effectively the threat assessment according to the weights indicating the significance of weapons and protected assets under diverse environments where weapons and protected assets are located, high utility and effect are expected when applied to an actual ground weapon system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.1001-1011
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• 2014

Smart Grid Devices could have security vulnerabilities that have legacy communication networks because of the fact that Smart Grid employs bi-directional communications and adopted a variety of communication interface. Consequently, it is required to build concrete response processes and to minimize the damage of the cyber attacks including security evaluation and certification methods. DCU is designed to collect meter data from numerous smart meter and send to utility's server so DCU installed between smart meter and utility's server. For this reason, If DCU compromised by attacker then attacker could use DCU to launching point for and attack on other devices. However, DCU's security evaluation and certification techniques do not suffice to be deployed in smart grid infrastructure. This work development DCU protection profile based on CC, it is expected that provide some assistance to DCU manufacturer for development of DCU security target and to DCU operator for help safety management of DCU.

• Journal of the Korean Institute of Navigation
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• v.10 no.1
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• pp.101-127
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• 1986

Transportation provides an infrastructure vital to economic growth, and it is an integral part of production . As a port is the interface between the maritime transport and domestic transport sectors, it certainly plays a key role in any economic development. Therefore, it is doubtless that inadequacy of a nation's port will depress the level of throughput, to the level where it fails to meet the target set by the national economic planning schemes. Korea is surrounded by the seas and the economic structure of Korea consists of processing trades, so that it cannot be overstated that substantial economy in maritime transport coasts can be achieved through the improvement of the port transport system. This paper treats the transportation process in Pusan Port by Queueing Simulation method, and the reasonable size of Pusan Port is suggested from the point of view of efficiency maximization. The results of the analysis are summarized as follows; 1) the utility rate is 47.91 percents in general piers, 85-52 percents in container piers, and waiting time 5.2hrs, in general piers, 0.8 hrs, in container piers, and the probability of maximum queue length 12 ships in general piers, 2 ships in container piers, and the probability of waiting is 44 percents in general piers, 8 percents in container pier. 2) in general piers, the improvement of app. 30 percents in port capacity is desirable for operating effectively concerning the current arrival rate. By introducing the traffic control ion container piers, there is no apparent necessity of port investment, but I is expected to reduce invisible congestion occurred along the waiting line. 3) On Pusan Port, the optimal utility rate and the optimal arrival rate for reducing waiting time are 3.5 to 4.0(hrs./ship) in general piers, 5.1 to 6.0(hrs./ship) in container piers.

• Management Science and Financial Engineering
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• v.10 no.1
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• pp.25-41
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• 2004

There have been many studies to build a model that can help investors construct optimal portfolio. Most of the previous models, however, are based upon the path-breaking Markowitz model (1959) which is a quantitative model. One of the most important problems with that kind of quantitative model is that, in reality, most of the investors use not only quantitative, but also qualitative information when they select their optimal portfolio. Since collecting both types of information from the markets are time consuming and expensive, making a set of target assets smaller, without suffering heavy loss in the rate of return, would attract investors. To extract only desired assets among all available assets, we need knowledge that identifies investors' preference for the risk of the assets. This study suggests two-layer decision-making rules capable of identifying an investor's risk preference and an architecture applying them to a quantitative portfolio model based on risk and expected return. Our knowledge-based portfolio system is to build an investor's preference-oriented portfolio. The empirical tests using the data from Korean capital markets show the results that our model contributes significantly to the construction of a better portfolio in the perspective of an investor's benefit/cost ratio than that produced by the existing portfolio models.

• Journal of Preventive Medicine and Public Health
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• v.42 no.6
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• pp.371-376
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• 2009

In this article, we reviewed the literature on risk assessment (RA) models with and without molecular genomic markers and the current utility of the markers in the pharmacogenetic field. Epidemiological risk assessment is applied using statistical models and equations established from current scientific knowledge of risk and disease. Several papers have reported that traditional RA tools have significant limitations in decision-making in management strategies for individuals as predictions of diseases and disease progression are inaccurate. Recently, the model added information on the genetic susceptibility factors that are expected to be most responsible for differences in individual risk. On the continuum of health care, from diagnosis to treatment, pharmacogenetics has been developed based on the accumulated knowledge of human genomic variation involving drug distribution and metabolism and the target of action, which has the potential to facilitate personalized medicine that can avoid therapeutic failure and serious side effects. There are many challenges for the applicability of genomic information in a clinical setting. Current uses of genetic markers for managing drug therapy and issues in the development of a valid biomarker in pharmacogenetics are discussed.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.37-45
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• 2008

It is expected that conditions of water resources will be changed in Korea in accordance with world wide climate change. In order to deal with this problem and find a way of minimizing the effect of future climate change, the usefulness of climate model simulation information is examined in this study. The objective of this study is to assess the applicability of GCM (General Circulation Model) information for Korean water resources management through uncertainty analysis. The methods are based on probabilistic measures of the effectiveness of GCM simulations of an indicator variable for discriminating high versus low regional observations of a target variable. The formulation uses the significance probability of the Kolmogorov-Smirnov test for detecting differences between two variables. An estimator that accounts for climate model simulation and spatial association between the GCM data and observed data is used. Atmospheric general circulation model (AGCM) simulations done by ECMWF (European Centre for Medium-Range Weather Forecasts) with a resolution of $2^{\circ}{\times}2^{\circ}$, and METRI (Meteorological Research Institute, Korea) with resolutions of $2^{\circ}{\times}2^{\circ}$ and $4^{\circ}{\times}5^{\circ}$, were used for indicator variables, while observed mean areal precipitation (MAP) data, discharge data and mean areal temperature data on the seven major river basins in Korea were used for target variables. The results show that GCM simulations are useful in discriminating the high from the low of the observed precipitation, discharge, and temperature values. Temperature especially can be useful regardless of model and season.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.1
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• pp.1-6
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• 2011

Purpose: Immobilizations used in order to maintain the reproducibility of a patient set-up and the stable posture for a long period are important more than anything else for the accurate treatment when the stereotactic body radiotherapy is underway. So the purpose of this study is to adapt the optimum immobilizations for the stereotactic body radiotherapy by comparing two commercial immobilizations with the self-manufactured immobilizations. Materials and Methods: Five people were selected for the experiment and three different immobilizations (A: Wing-board, B: BodyFix system, C: Arm up holder with vac-lock) were used to each target. After deciding on the target's most stable respiratory cycles, the targets were asked to wear a goggle monitor and maintain their respiration regularly for thirty minutes to obtain the respiratory signals. To analyze the respiratory signal, the standard deviation and the variation value of the peak value and the valley value of the respiratory signal were separated by time zone with the self-developed program at the hospital and each tie-downs were compared for the estimation by calculating a comparative index using the above. Results: The stability of each immobilizations were measured in consideration of deviation changes studied in each respiratory time lapse. Comparative indexes of each immobilizations of each experimenter are shown to be A: 11.20, B: 4.87, C: 1.63 / A: 3.94, B: 0.67, C: 0.13 / A: 2.41, B: 0.29, C: 0.04 / A: 0.16, B: 0.19, C: 0.007 / A: 35.70, B: 2.37, C: 1.86. And when all five experimenters wore the immobilizations C, the test proved the most stable value while four people wearing A and one man wearing D expressed relatively the most unstable respiratory outcomes. Conclusion: The self-developed immobilizations, so called the arm up holder vac-lock for the stereotactic body radiotherapy is expected to improve the effect of the treatment by decreasing the intra-fraction organ motions because it keeps the respiration more stable than other two immobilizations. Particularly in case of the stereotactic body therapy which requires the maintenance of set-up state for a long time, the self-developed immobilizations is thought to more useful for stereotactic body radiotherapy rather than the rest two immobilizations with instable respiratory cycle as time passes.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.441-477
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• 2020

There have been raised other environmental issues related to remediated soils piled up in numerous carry-out processing facilities because a considerable quantity of them have been produced every year, but most of them have not been relevantly reused or recycled. Thus, this article reports the trend of researches on the development of techniques to restore the quality of remediated soils to activate their reuse and recycling. Firstly, the tendency of change in soil properties through remediation processes was looked over, and then the degradation of soil quality was characterized according to the type of remediation processes. Besides, the direction of policy to promote the reuse and recycling of remediated soils was introduced, and finally, the future works needed were suggested. This article was prepared based on the results of the survey of domestic and foreign literature. A number of literature were reviewed to scrutinize the change of soil properties due to remediation processes and diverse techniques for the amendment and restoration of remediated soils. Furthermore, the policies related to the reuse and recycling of remediated soils were arranged with the reference of the first and second versions of the Soil Conservation Master Plan of Korea. The literature survey focused on three kinds of remediation technologies, such as land farming, soil washing, and thermal desorption, which were most frequently used so far in Korea. The results indicate that the tendency of change in soil properties was significantly different depending on the type of remediation processes applied, and the degradation characteristics of soil quality were also totally different between them. The soil amendment and restoration can be categorized as three techniques depending on the type of substances used, such as inorganic, organic, and biological ones. Diverse individual materials have been used, and the soil properties improved or enhanced were dependent on the type of specific materials utilized. However, few studies on the restoration of soil qualities degraded during the remediation processes have not been carried out so far. The second Soil Conservation Master Plan states the quality certification and target management system of remediated soils, and it is expected that their reuse and recycling will be facilitated hereafter. With the consideration of the type of remediation processes implemented and public utility, the restoration technologies of remediated soils should be developed for the vitalization of their reuse and recycling. Besides, practical and specific measures should be taken to support the policy specified in the second Soil Conservation Master Plan and to promote reuse/recycling of remediated soils.