• Journal of Korea Game Society
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• v.5 no.2
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• pp.19-27
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• 2005

The core price policy of on-line game marketing are FPP(Fixed Pre Paid model and PPU(Pay Per Use) model. These two models have been a on-line game company's billing system and a fundamental of MMORPG in Korea. However, they took root billing system only for first movers recently. In now, the market share of several first movers is exceeding 80%, late movers witch have same billing system cannot take part in pair competition. Even though in MMORPG, many games of late movers were favorably noticed by a lot of gamers during Evaluation. Test, a lot of companies are bankrupt before make business. Late Movers declare free game first thing, they maintain their existence and win over customers in on-line game market. And next, they guarantee item selling, give multiple experience value and game money, at last, induce their customers to pay service. As it makes trouble between pay user and free user, and it linked up with the collapse of game contents balance that designed for FPP billing system, And then meet unexpected result which reduction of game life cycle. In this Paper, we classified several contents services based on game contents, and suggested contents premium services which adopted low cost strategy lead to micro payment. we hope it will apply to late movers' new billing system in MMORPG.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.245-260
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• 2012

This study aims to analyze the change in the correlation between the index values and qualitative quantitative evaluation elements by applying 'the decile of total number of articles' instead of the average annual number of articles in Kor-Factor2, and to evaluate the distinction ability between registered journals and register nominee journals of the KCI. The correlation between the index values and qualitative quantitative evaluation elements was analyzed by calculating the correlation coefficient between the index values and the evaluation elements, and then the correlation was compared with that of Kor-Factor2. To evaluate the distinction ability, we carried out independent samples t-test on the mean difference between index values of register nominee journal group and registered journal group and compared the mean difference with that of Kor-Factor2, IF and journal h-index. As a result, we found that the modified index applying the decile of total number of articles was effective in improving the balance among the correlation between the index values and qualitative quantitative evaluation elements compared to Kor-Factor2, and the new index appeared to be superior to other indexes on distinction ability of the journal's registration condition in the KCI.

• Toxicological Research
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• v.34 no.4
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• pp.333-341
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• 2018

Ferulate is a phenolic compound abundant in wheat germ and bran and has been investigated for its beneficial activities. The aim of the present study is to evaluate the efficacy of ferulate against the oxidative stress-induced imbalance of protein tyrosine kinases (PTKs), protein tyrosine phosphatases (PTPs), and serine/threonine protein phosphatase 2A (PP2A), in connection with our previous finding that oxidative stress-induced imbalance of PTKs and PTPs is linked with proinflammatory nuclear factor-kappa B $(NF-{\kappa}B)$ activation. To test the effects of ferulate on this process, we utilized two oxidative stress-induced inflammatory models. First, YPEN-1 cells were pretreated with ferulate for 1 hr prior to the administration of 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH). Second, 20-month-old Sprague-Dawley rats were fed ferulate for 10 days. After ferulate treatment, the activities of PTKs, PTPs, and PP2A were measured because these proteins either directly or indirectly promote $NF-{\kappa}B$ activation. Our results revealed that in YPEN-1 cells, ferulate effectively suppressed AAPH-induced increases in reactive oxygen species (ROS) and $NF-{\kappa}B$ activity, as well as AAPH-induced PTK activation. Furthermore, ferulate also inhibited AAPH-induced PTP and PP2A inactivation. In the aged kidney model, ferulate suppressed aging-induced activation of PTKs and ameliorated aging-induced inactivation of PTPs and PP2A. Thus, herein we demonstrated that ferulate could modulate PTK/PTP balance against oxidative stress-induced inactivation of PTPs and PP2A, which is closely linked with $NF-{\kappa}B$ activation. Based on these results, the ability of ferulate to modulate oxidative stress-related inflammatory processes is established, which suggests that this compound could act as a novel therapeutic agent.

• International Commerce and Information Review
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• v.13 no.3
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• pp.377-401
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• 2011

Under the WTO system, direct export support system that provides financial and tax related support is altogether prohibited. This presented an obstacle in strengthening competitiveness of Korean export business and in increasing exports continuously. One of the methods used to solve this problem was to actively leverage export insurance. In Korea, export insurance services have been conducted by the Korea Trade Insurance Corporation (k-sure) to promote export. Korea has been among the world's active users of the export insurance system. Given this situation, this paper examines the effectiveness of the Korea export insurance system in the promotion of export. In particular, this study analyzed about discriminating effects of the export insurance on the export of big and small-medium business. In order to analyze, We introduce a Export Supply Function model. In this paper, We construct two model. The one is about big business, the other is small-medium business. For empirical analysis, unit-root test was conducted to understand the safety of time series. The results show that all variables are not I(0) time series. Instead, they are I(1) time series. To this, cointegration verification was conducted based on the use of Johansen verification method to define the existence (or non-existence) of long-term balance relationship among variables. The results come out as follows. The export insurance of big business has a stronger effect on export than that of small-medium business. The cause of these results is due to the distinct structure of Korea industries. In view of the fact that the insurance can make the risk decreased. We can say that the export insurance affects the export of a high-risk country.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.635-642
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• 2008

In recent years, epoxy-coated reinforcing bars have been widely used in order to prevent the corrosion of ordinary reinforcing bar. However, they have a bad balance between performance and cost. Especially, they have a brittleness properties, low bond strength to cement concrete and no good bend-ability in the field. The purpose of this study is to evaluate the tensile properties and adhesion of hybrid-type anti-corrosion polymer cement slurry (PCS). PCSs are prepared with four types polymer dispersions using fly ash and silica fume, and tested for proper coating thickness, tensile properties, adhesion to steel plate and bend-ability. From the test results, the viscosity of PCS is effected by polymer dispersion types, and is a little decreased by using fly ash. The coating thickness of PCS has a proper thickness at polymer-binder ratio of 100%. It is apparent that the coating thickness has various values according to viscosity of PCS, water-binder ratio and polymer-binder rato. PCS has a good various anticorrosion properties and physical properties such as tensile strength, adhesion and bend-ability. It is also recommended that proper coating thickness to reinforcing bar is in the ranges of 150 to $250{\mu}m$ for bond strength, adhesion and bend-ability. It is also expected that the coated reinforcing bar using PCS is widely used instead of epoxy coated reinforcing bar in the industrial field.

• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1183-1194
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• 2004

Network partitioning problem is to partition a network into multiple blocks such that the size of cutset is minimized while keeping the block sizes balanced. Among these, iterative algorithms are regarded as simple and efficient which are based on cell move of Fiduccia and Mattheyses algorithm, Sanchis algorithm, or Kernighan and Lin algorithm. All these algorithms stipulate balanced block size as a constraint that should be satisfied, which makes a cell movement be inefficient. Park and Park introduced a balancing coefficient R by which the block size balance is considered as a part of partitioning cost, not as a constraint. However, Park and Park's algorithm has a square time complexity with respect to the number of cells. In this paper, we proposed Bucket algorithm that has a linear time complexity with respect to the number of cells, while taking advantage of the balancing coefficient. Reducing time complexity is made possible by a simple observation that balancing cost does not vary so much when a cell moves. Bucket data structure is used to maintain partitioning cost efficiently. Experimental results for MCNC test sets show that cutset size of proposed algorithm is 63.33% 92.38% of that of Sanchis algorithm while our algorithm satisfies predefined balancing constraints and acceptable execution time.

• Journal of KIISE:Software and Applications
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• v.28 no.9
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• pp.669-680
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• 2001

Genetic Algorithms are optimization algorithm that mimics biological evolution to solve optimization problems. Genetic algorithms provide an alternative to traditional optimization techniques by using directed random searches to locate optimal solutions in complex fitness landscapes. Hybrid genetic algorithm that is combined with local search called learning can sustain the balance between exploration and exploitation. The genetic traits that each individual in the population learns through evolution are transferred back to the next generation, and when this learning is combined with genetic algorithm we can expect the improvement of the search speed. This paper proposes a genetic algorithm based Cellular Learning with accelerated learning capability for function optimization. Proposed Cellular Learning strategy is based on periodic and convergent behaviors in cellular automata, and on the theory of transmitting to offspring the knowledge and experience that organisms acquire in their lifetime. We compared the search efficiency of Cellular Learning strategy with those of Lamarckian and Baldwin Effect in hybrid genetic algorithm. We showed that the local improvement by cellular learning could enhance the global performance higher by evaluating their performance through the experiment of various test bed functions and also showed that proposed learning strategy could find out the better global optima than conventional method.

• Korean Journal of Community Nutrition
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• v.14 no.3
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• pp.255-265
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• 2009

This study was investigated nutrient intakes and dietary evaluation index of the healthy subjects over 85 of Sunchang County to explore the improved dietary pattern for healthy aging of the elderly. The survey was conducted by personal interview to 161 elderly subjects (59 males and 102 females over 85) in 2006, and their daily dietary intake was assessed by 24-hr recalls and weighing one meal. The daily energy intakes of males were 1,335 ${\pm}$ 67 kcal, and those of females were 1,095 ${\pm}$ 38 kcal comprised of 66.8% and 68.4% of the EER for the age group of 75. The proportions of energy from carbohydrate : protein : lipid were 70.7 : 14.6 : 14.6 for males and 68.6 : 14.0 : 17.4 for females. The average protein intakes were 95.4% for males and 85.0% for females of RI, and the average calcium intakes were 54.3% for males and 43.6% for females of RI. The daily vitamin intakes were below 70% except vitamin A, vitamin $B_6$, and vitamin E. The proportion of the relative risk groups of protein, phosphate, iron and vitamin A ranged 40-49% of RI over 75 year groups. The other nutrient intakes showed that there were over 50% risk groups. Especially for nutrients such as calcium, vitamin $B_1$, vitamin $B_2$, vitamin C, folate and niacin over 70% of the subjects were under risk. The median value of all nutrient intakes did not reach AI. The INQ of nutrients were over 0.8 except for folate and vitamin C. Calcium intakes were relatively low and needed attention. However, the ratio of calcium and phosphate showed 1 : 1.6, which appeared to be superior to the other districts. The DVS were higher as the dietary balance scores, KDDS were higher, and the groups with high KDDS had high intakes of nutrients compared to the groups with low KDDS. The high risk groups as judged by simple nutrition screening test had lower nutrient intakes than the groups of middle risk or low risk groups. The subjects in Sunchang area had relatively low intakes of several nutrients. However, judging from the desirable patterns of the energy proportion from three major nutrients, ratio of calcium and phosphate and INQ of nutrients there is a possibility that extended healthy aging might be related to the quality of nutrients and relative ratio between nutrients. To improve nutrient status of the elderly of the surveyed area further application involving KDDS and DVS appeared to be required.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.383-396
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• 1992

In order to find out the reasons for the excessive accumulation of certain fertilizer elements in arable land in Korea, which may be a detrimental factor for her sustainable agriculture in the future, total requirement of fertilizers were estimated from the huge number of soil test data obtained throughout the country using the fertilizer requirement models based on the soil analysis data and the concepts of multi nutrient factor balance or starter fertiliazer. The total fertilizer requirements estimated based on the present soil fertility status were much less than those estimated from the suspected cropping area of various crops cultivated depending on the conventional fertilizer recommendation for each crops or the actual amount of fertilizer elements consumed through National Agricultural Cooporative Federation(NACF). The excessive accumulation of certain fertilizer elements in arable land in Korea must be due to excessively high dose of chemical fertilizers as well as those farm wastes such as animal wasts produced unexpectedly in large amounts or crop residues. And it is suggested that the improved fertilizer recommendation must be developed in consideration both with the soil fertility status and the amounts of nutrient removal by each crop, and that the high analyzed complex fertilizers commonly used by farmers must ugently be developed in a form containing low P and K with Mg and slow release type N for the better balanced management practices of soil fertility by farmers arid for their practices of sustainable agriculture.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.43-54
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• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.