• Journal of the Korea Computer Graphics Society
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• v.26 no.1
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• pp.17-25
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• 2020

We present a novel multi-core CPU based parallel algorithm for the cell-connectivity information extraction algorithm, which is one of the preprocessing steps for volume rendering of unstructured grid data. We first check the synchronization issues when parallelizing the prior serial algorithm naively. Then, we propose a 3-step parallel algorithm that achieves high parallelization efficiency by removing synchronization in each step. Also, our 3-step algorithm improves the cache utilization efficiency by increasing the spatial locality for the duplicated triangle test process, which is the core operation of building cell-connectivity information. We further improve the efficiency of our parallel algorithm by employing a memory pool for each thread. To check the benefit of our approach, we implemented our method on a system consisting of two octa-core CPUs and measured the performance. As a result, our method shows continuous performance improvement as we add threads. Also, it achieves up to 82.9 times higher performance compared with the prior serial algorithm when we use thirty-two threads (sixteen physical cores). These results demonstrate the high parallelization efficiency and high cache utilization efficiency of our method. Also, it validates the suitability of our algorithm for large-scale unstructured data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.303-310
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• 2018

One of most shocking headlines is a serious chain collision accident (CCA). The development of CCA has a temporal and spatial locality, and the information of the CCA is time-critical. Due to these characteristics of CCA, traffic accident information should be rapidly propagated to drivers in order to reduce chain collisions, right after the first accident occurs. Inter-vehicle communication (IVC) based on ad-hoc communication is one of promising alternatives for locally urgent information propagation. Despite this potential of IVC, research for the effects of IVC on the reduction of CCA has not been reported so far. Therefore, this study develops the parallel platform of microscopic vehicle and IVC communication simulators and then analyses the effects of IVC on the reduction of the second collision related to a series of vehicles. To demonstrate the potential of the IVC-based propagation of urgent traffic accident information for the reduction of CCA, the reduction of approaching-vehicle speed, the propagation speed of accident information, and then the reduction of CCA were analysed, respectively, according to scenarios of combination of market rates and traffic volumes. The analysis results showed that CCA can be effectively reduced to 40~60% and 80~82% at the penetration rates of 10% and 50%, respectively.

• Journal of Korea Water Resources Association
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• v.30 no.2
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• pp.165-175
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• 1997

This is to study the characteristics of available water resources (AWR) of the eastern coastal area in Korea. A rating curve was suggested at Yangyang water level station of the Yangyangnamdai river. Annual mean precipitation of this area is 1365.8mm. Annual mean precipitation in central and northern area of eastern coastal area is more than that of southern area because of orographic precipitation occurred by the north-easterly air flow from the East sea. By the correlation analysis of monthly rainfall depths between rainfall gauging stations it is presented that the rainfall gauging stations located in coastal region have the regional representativity, but the rainfall gauging stations located in the westward of mountains have a strong locality. AWR of eastern coastal area by the application of runoff coefficient 0.665 is 1134.5X106m3 and 28.6 percentage for total water resources. In each watershed AWR is 193.7X106m3 in the Yangyangnamdai river, 109X106m3 in the Kangnungnamdai river, and 146.0X106m3 in the Samcheokosip river. The seasonal changes of 30/3% in summer and 19.1% in water, and those of the AWR to total water resources are 86.3% in winter, 60.1% in spring, 50.1% in autumn, and 25.7% in summer. The results of this study may be used to establish the water resources planning of eastern coastal area.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.1
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• pp.89-99
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• 2014

The current Development Impact Fee (DIF) Zoning Law allows Korean localities to designate the DIF Zone for the areas where there have been up-zoning in land-uses due to any minute additions and/or amendments in the existing clauses or provisions in the National Territory Planning Law as well as all other laws related to urban and regional planning. In reality, however, it is almost impossible to trace the sporadic and infinitesimal changes that might occur in every corner of the statutory clauses of a great number of planning related laws. This study, in an effort to overcome such practical difficulties, tries to chase the time-series zoning alterations in especially the consecutive land-use information layers of the Korea Land Information System (KLIS) as comparable analogues of the outcomes of the amendments in various planning laws. A study locality is chosen among the entire localities in the Capital Region based on the selection criteria dictated by the DIF Zoning Law such as the population- and building permit increase rate. It has been verified that the methodology suggested herein is practically applicable and successfully capable of extracting a number of DIF zones with considerable areal sizes, which could not have otherwise been possible. The consequences of this study, in this context, are expected to contribute to prevent the uncontrolled developments as the DIF Zoning Law itself was originally intended to achieve.

• Journal of the Economic Geographical Society of Korea
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• v.8 no.2
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• pp.267-284
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• 2005

This study analyzes the effects of localities' competitiveness which can contribute to employment growth in industries, on economic development in the local jurisdictions. For this analysis, such competitiveness is measured by competitive shares calculated from the application of a shift-share method to the employment growth in industries each locality witnessed over the 1990s. And we use annual population growth rate and average annual per capita income (substituted by per capita head tax derived from income tax) of the early 2000s as variables of local economic development. The analysis targets 167 local jurisdictions in Korea for the employment growth in industries, and is mainly placed in a spatial econometric setting. The results of analysis are as follows : The competitive share of manufacturing has the effect of increasing annual population growth rate whereas that of construction has a negative effect on the population growth rate. As well, the competitive shares of manufacturing and of construction negatively influence average annual per capita income while that of community, social and personal services positively affects the income.

• Journal of the Korean association of regional geographers
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• v.15 no.5
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• pp.635-654
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• 2009

Recently, concepts of multicultural society and/or multiculturalism have been not only widely discussed across several disciplines, but also actively promoted in government's policy, as the in-flow of foreign immigrants has increased rapidly. This paper suggests the term 'multicultural space' instead of multicultural society in a sense that both international migration of immigrants and their accommodation to a certain locality presuppose a spatial dimension. This paper also points out that the term multiculturalsim should be used very carefully, because this term includes a normative character implied in a sense of recognition of ethnic and cultural diversity and difference on the one hand, and an ideological one reflected on strategic policies of capital and the state on the other. On the basis of recognition of these problems, this paper tries to reformulate spatially the concept of muticultural society which has been supposed to be constructed due to rapidly increasing foreign immigrants, emphasizing some usefulness of multi-scalar approach. It then analyzes economic and political contexts of transnational migration, providing a criticism of multiculturalism as an ideological logic of capital and the state in transnational captialism. Finally it put a stress upon importance of struggle for spaces of recognition as a new glocal ethics in the age of post-globalization.

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.664-674
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• 2004

The trajectory preservation property that stores only one trajectory in a leaf node is the most important feature of an index structure, such as the TB-tree for retrieving object's moving paths in the spatio-temporal space. It performs well in trajectory-related queries such as navigational queries and combined queries. But, the MBR of non-leaf nodes in the TB-tree have large amounts of dead space because trajectory preservation is achieved at the sacrifice of the spatial locality of trajectories. As dead space increases, the overlap between nodes also increases, and, thus, the classical range query cost increases. We present a new split policy and entry relocation policies, which have no deterioration of the performance for trajectory-related queries, for improving the performance of range queries. To maximally reduce the dead space of a non-leaf node's MBR, the Maximal Area Reduction (MAR) policy is used as a split policy for non-leaf nodes. The entry relocation policy induces entries in non-leaf nodes to exchange each other for the purpose of reducing dead spaces in these nodes. We propose two algorithms for the entry relocation policy, and evaluate the performance studies of new algorithms comparing to the TB-tree under a varying set of spatio-temporal queries.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.121-150
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• 1997

This Study puts the purpose to explicate the regionalities of land-lease farming by a comparative analisis of the five case study areas in Kungpook Province as the agricultural space system of Teagu metropolitan city. For the regional comparative analysis the province was divided into the three zones with the distance from the central city(Teagu): urban fringes, intermediate and remote zone, and then subdivided into the five regions by farming systems : horticulture, rice-farming, and dry-field farming. The data were collected from 77 land-leasing farmers by questionnaire and interview with farm managers in 5 sample villages representing the regionalities of the above five regions respectively. In spite of relatively restricted scope of the research areas, the analytical results appear remarkable regional differences in the characteristics of land-lease farming within a single agricultural space system. In the final analysis the regionalities of the five land-lease farming regions could be described respectively as follows. (1) Koryong-Gun in the inner urban fringe zone : The developing land-lease farming region of commercialized suburban horticulture with medium scale. (2) Songju-Gun in the outer urban fringe zone : The developing land-lease farming region of highly commercialized horticulture with large scale. (3) Uisong-Gun in the intermediate zone : The stagnated land-lease farming region of commercialized rice-farming with large scale. (4) Yongil-Gun in the intermediate zone : The stagnated land-lease farming region of commercializing dry-field farming with medium scale. (5) Ponghwa-Gun in the remote zone : The stagnated and delayed region in commercializing of intermountain dry-field land-lease farming with small scale. These varied regionalities resulted from the diverse spatiality as a complex of spatial orders and localities. The spatial orders in this study are frequently recognizable as a form of distance-decay, and the locality of a region is determined mostly by the its peculiarity of physical and population conditions. In the comparative analysis of the regionalities the degree of commercialization of a region is a most comprehensive and useful frame of reference because it reflects the degree of development of capitalist land-lease farming. Finally these apparent regional differentiations of land-lease farming within a agricultural space system raise the problem of impracticality of the existing uniform logic on the land-lease farming such as "large scale farms share larger part of leased farmland." This problem suggests the urgent need of reappraisal of many aspatial logics and theories on the land-lease farming.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.99-112
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• 2021

This study was performed to predict spatial change of future forestland area in South Korea at regional level for supporting forest-related plans established by local governments. In the study, land use was classified to three types which are forestland, agricultural land, and urban and other lands. A logistic regression model was developed using transitional interaction between each land use type and topographical factors, land use restriction factors, socioeconomic indices, and development infrastructures. In this model, change probability from a target land use type to other land use types was estimated using raster dataset(30m×30m) for each variable. With priority order map based on the probability of land use change, the total annual amount of land use change was allocated to the cells in the order of the highest transition potential for the spatial analysis. In results, it was found that slope degree and slope standard value by the local government were the main factors affecting the probability of change from forestland to urban and other land. Also, forestland was more likely to change to urban and other land in the conditions of a more gentle slope, lower slope criterion allowed to developed, and higher land price and population density. Consequently, it was predicted that forestland area would decrease by 2027 due to the change from forestland to urban and others, especially in metropolitan and major cities, and that forestland area would increase between 2028 and 2050 in the most local provincial cities except Seoul, Gyeonggi-do, and Jeju Island due to locality extinction with decline in population. Thus, local government is required to set an adequate forestland use criterion for balanced development, reasonable use and conservation, and to establish the regional forest strategies and policies considering the future land use change trends.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.5
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• pp.60-70
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• 2017

This study traces the development of physic gardens in Korea and explores their significance in the history of landscape architecture. For this purpose, records related to physic gardens from medical sources from the period of the Three States to the Joseon dynasty, when herbal medicine was systematized as a field, were searched. Physic gardens had been developed by the time of the late Goryeo and early Joseon dynasties, in the 13th and the 15th centuries. Yakpo(kitchen gardens for medicinal herbs) were cultivated by a group of new high-level officials in the late Goryeo dynasty, when an increasing interest in hyangyak(native herbs) emerged under the influence of the Neo-Confucian perspective on nature, which emphasized locality. The sources analyzed in this study confirm that physic gardens called jong-yakjeon(royal medicinal herb gardens) were in operation in the early Joseon dynasty when policies to investigate, discover, cultivate, and research native herbs were put into place. It is likely that the jong-yakjeon were established at the beginning of the Joseon dynasty as subsidiary facilities under its central medical institutions, the Naeuiwon and Hyeminseo, and then declined in the late Joseon dynasty. Jong-yakjeon can be confirmed to have existed in the mid-15th century. Physic gardens were located in several places outside the Fortress Wall of Hanyang, such as Yakhyeon, Yuldo, Yeoudo, and Saari. The total area encompassed by physic gardens was about 160,000 square meters in the early 18th century. In jong-yakjeon, dozens of medicinal herbs were cultivated, including Schizonepeta tenuifolia var. japonica, Rehmannia glutinosa, and Glycyrrhiza uralensis Fischer, and these gardens were operated by physicians dispatched from the Naeuiwon and dozens of provincial slaves. In conclusion, the jong-yakjeon were similar to the physic gardens of Renaissance medical universities in that they reflected the interest in and development of theories about new herbs, and were similar to the physic gardens of medieval castles and monasteries in terms of species types, location, and function. This paper has limitations in that it does not present the specific spatial forms of the yakpo or the jong-yakjeon. Nevertheless, this paper is significant for the field of garden history because it shows that physic gardens in Korea appeared in the late Goryeo and early Joseon dynasties concomitantly with the development of medicine towards native herbs and functioned as utilitarian gardens to cultivate community remedies.