• Spatial Information Research
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• v.16 no.1
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• pp.19-32
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• 2008

Usually in South Korea, land cover type and topographic undulation are frequently changed even in a narrow area. However, most of researches using aerial LIDAR(LIght Detection And Ranging) data in abroad had been acquired in the study areas to be changed infrequently. This research was performed to explore reconstruction methodologies of 3D surface models considering the distribution of land cover type and topographic undulation. Composed of variously undulatory forests, rocky river beds and man-made land cover such as streets, trees, buildings, parking lots and so on, an area was selected for the research. First of all, the area was divided into three zones based on land cover type and topographic undulation using its aerial ortho-photo. Then, aerial LIDAR data was clipped by each zone and different 3D modeling processes were applied to each clipped data before integration of each models and reconstruction of overall model. These kinds of processes might be effectively applied to landscape management, forest inventory and digital map composition. Besides, they would be useful to resolve less- or over-extracted problems caused by simple rectangle zoning when an usual data processing of aerial LIDAR.

• Spatial Information Research
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• v.22 no.5
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• pp.65-75
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• 2014

Bus headway plays an important role not only in determining the passenger waiting time and bus service quality, but also in influencing the bus operation cost and passenger demand. Previous research on headway control has considered only an hourly difference in the distribution of ridership between peak and non-peak hours. However, this approach is too simple to help manage ridership demand fluctuations in a short time scale; thus passengers' waiting cost will be generated when ridership demand exceeds the supply of bus services. Moreover, bus ridership demand varies by station location and traffic situation. To address this concern, we propose a headway control algorithm for minimizing the waiting time cost by using Smart Card data. We also provide proof of the convergence of the algorithm to the desired headway allocation using a set of preconditions of political waiting time guarantees and available fleet constraints. For model verification, the data from the No. 143 bus line in Seoul were used. The results show that the total savings in cost totaled approximately 600,000 won per day when we apply the time-value cost of waiting time. Thus, we can expect that cost savings will be more pronounced when the algorithm is applied to larger systems.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.2
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• pp.117-131
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• 2016

This study aims to analyze the spatial accessibilities to urban greens considering the catchment areas of urban parks to improve those areas with lower spatial accessibility in the neighborhood units. Nam-gu in Daegu was selected as the study area. In the results of the analysis of 16 existing parks, Daemyung6-dong and Daemyung5-dong had high ratios of green service area to administrative district, with values of 94.4% and 92.3%, respectively. Low ratios of green service area(vulnerable area of green service) were recorded in Icheondong(1.6%) and Daemyung10-dong(24.1%). However, the ratio of Icheondong may increase by 88.6%, when the 12 unexecuted urban parks are established. The ratio of Daemyung10-dong can also increase up to 40.1% by establishing green spaces in public institutions such as government offices and schools. This study suggests possibilities to improve the spatial accessibilities to urban parks and indicates the policies required for enhancing the even distribution of green spaces.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.153-170
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• 2013

This study was conducted to analyze the thermal comfort in the urban neighborhood park and to obtain a plan for improvement of the thermal environment. First, in the result of the analysis of the distribution characteristics of the park's main thermal environment factors and differences among types of space, temperature, relative humidity, and wind speed did not show a clear difference spatially. However, the median radiant temperature showed great differences according to the openness of the space and the covering material. According to the evaluation of thermal comfort by types of space based on derived thermal environmental factors, the PMV value of the square was the highest at 4.39, the paths showed 2.58, greenery 1.90, and resting spaces 0.42. In the result of the PMV regression model established for the evaluation of the significance of these thermal environment factors that decide thermal comfort, it showed that the relative significance to the PMV was as follows in decreasing order: median radiant temperature(1.084), wind speed(-0.280), temperature(0.013), and relative humidity(-0.009). When conducting a scenario analysis on the areas with need for improvement in thermal environment, it was found that through reflectivity, color and the change in the physical properties of packing materials the thermal comfort felt by the body could be improved, and it is believed that through this the improvement plan can be established.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.139-151
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• 2017

The habitat preference of roe deers(Capreolus pygargus) in Jeju island, South Korea was analyzed by using their occurrence probability in MaxEnt model in this study. Totally 490 surveying data were gathered and 15 environmental variables were chosen for the model in which 6 variables out of 15 ones were filtered and finally removed because of there being higher correlation(over 0.7 in correlation coefficient). According to the modeling, roe deers were known to prefer the area ranging from 200 to 700 meter and over 1,500 meter in sea level, where there were not many dominant tree and/or dominant vegetation with low density so that understory vegetation can grow well with plentiful sunlight and can be used as a food of herbivore like roe deers. Otherwise, the region ranging from 700 to 1,500 meter was mostly covered with high density vegetation which cut off sunlight trying to penetrate through the dominant vegetation. It can cause a lower density of vegetation on surface, which can not attract to roe deers.

• International Commerce and Information Review
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• v.17 no.1
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• pp.217-240
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• 2015

This paper uses the modified gravity model of international trade to examine the impact of ODA on the export of Korea to 28 aid recipients. In this perspective, the study includes recipient's economic size, trade openness, population, donor's scale of aid and distance between them as key determinants of the export of Korea by using panel data over the period of 2005-2012. To do this task, important econometric methods are fulfilled to test the model adequately, such as panel unit root and panel co-integration test. In addition, the study incorporated the panel OLS, panel GLM and panel EGLS methods. The empirical analysis clearly showed that an increase in Korea's ODA promotes its own exports. The coefficients of recipients's per capita GDP, population and trade openness have a positive impact on Korea's export respectively, while distance between them has a negative impact. Regarding regional dummy variables, aid for the region of Africa and America have a negative impact on Korea's export. Overall, the main implication of this study is that even if it emphasized Korea's economic interests as determinants of ODA disbursements, but it also suggests that an improvement of recipient's economic development, income distribution and educational environment can be an important concern in the future.

• International Commerce and Information Review
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• v.15 no.4
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• pp.27-46
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• 2013

The objective of this study is to analyze the export performance of Korean eyewear products in China market, and derive some implications from the results of the analysis. For the analysis, the statistical data from 2003 to 2013 produced by Korea International Trade Association were used, and Market Share Index, Trade Specialization Index, and Revealed Comparative Advantage Index as an analyzing method were selected. According to the analysis, Korea's eyewear goods market share in China's glasses market was less than 5% on average during the analyzing period amid recording chronic deficits in Korea's eyewear commodities trade to China and by product, contact lenses were competitive, while eyeglass frames, eyeglasses, eyeglass lenses and sunglasses were not competitive. The suggestions for revitalizing Korea's eyewear products exports to the China market are as follows: First, Korea's glasses industry must enhance the ability to develop creative and distinctive product design to meet the needs of Chinese consumers. Second, to meet Chinese consumers preferences, Korea's glasses industry must actively produce new materials and functional products. Third, Korea's glasses industry must improve brand awareness through the continuous launch of new products for the Chinese market. Fourth, Korea's glasses industry must actively promote strategic alliances with domestic and foreign enterprises, and the Hallyu marketing. Fifth, Korea's glasses industry must reasonably improve the unusual products distribution system. Finally, The government must prepare a systematic support system for eyeglasses industry.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.6
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• pp.57-66
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• 2005

In this paper, a new rehabilitation training system was developed to improve equilibrium sense by combining virtual reality technology with a fixed exercise bicycle. The subjects consisted of two groups. A group of young people, was compared against a group of elderly. We measured three different running modes of virtual bicycle system with two successive sets. The parameters measured were running time, velocity, the weight movement, the degree of the deviation from the road, and the variables about the center of pressure. The repeated training, our results showed that the running capability of the elderly improve compared. In addition, it was found out that the ability of postural control and the equilibrium sense was improved with the presentation of the visual feedback information of the distribution of weight. From the results of this experiment, we showed that our newly developed system might be useful in the diagnosis of equilibrium sense or in the improvement of the sense of sight and, somatic, and vestibular sense of the elderly in the field of rehabilitation training.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.3
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• pp.70-78
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• 2000

In this study, a new method for canceling MRI artifacts through the motion translation of image plane is presented Breathing often makes problems in a clinical diagnosis. Assuming that the head moves up and down due to breathing, rigid translational motions in only y(phase encoding axis) direction are treated Unlike the conventional Iterative phase retrieval algorithm, this method is based on the MRI imaging process and analyzing of Image property A new constraint condition with which the motion component and the true image component in the MRI signal can be separated by a simple algebraic operation is extracted After the x(read out) directional Fourier transformation of MRI signal is done, the y(phase encoding) directional spectrum phasing value is Just an algebraic sum of the Image component and the motion component Meanwhile, as It is known that the density of subcutaneous fat area is almost uniform in the head tomographs, the density distribution along a y directional line on this fat area is regarded as symmetric shape If the density function is symmetric, then the phase of spectrum changes linearly with the position Hence, the departure component from the linear function can be separated as the motion component Based on this constrant condition, the new method of artifact cancellation is presented Finally, the effectiveness of this algorithm IS shown by using a phantom with simulated motions.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.19-32
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• 2016

Due to the increasing fiscal burden and structural unbalanced premium/benefit costs, the new reform on the government employees pension system (GEPS) was considered even after the recent reform in 2009. This article examines the various effects of recent amendment in 2015 on GEPS using a simple probabilistic model. We consider effects on both sides, the pensioners and the government. First of all, the expected net value of pension payment for an individual employee was calculated based on the supposed survival distribution. The fairness of individual pension holders was compared using the benefit-cost ratio. Secondly, from pension system users' point of view, the default probability and the government subsidy were examined by Monte-carlo simulation. From the simulation experiment, we could see that the 2015 reform plan indeed reduces the default probability and the size of the fiscal burden of government by increasing the premium and decreasing the benefit. However, the size of the effect is not very standout at this moment because the number of new employees who are fully subject to the reform will be much smaller than the number of previous employees for a while. Thus, the effect of the reform is expected to appear in a slow manner.