• Proceedings of the KSR Conference
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• 2010.06a
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• pp.640-649
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• 2010

Coarse granular materials such as gravel and crushed stone have been used as an important fill materials to large soil structure of railway, road, dam and so on. Although much studies for general soil materials have been carried out domestically, the studies for coarse materials were insufficient. Particularly, it is the level in which the study for dynamic properties(Elastic modulus and damping ratio) of coarse materials, applies the foreign country literature. This is due to the lack of large equipment for element test. But large soil structures made of coarse granular materials are generally important infrastructures. Therefore, the reliable design parameters for coarse materials should be obtained for safe and economic design, construction and maintenance. Triaxial test is the laboratory test method that is capable of controlling a confining pressure and boundary condition. In this project, we made a multi-purpose large triaxial testing system. This testing system is able to test coarse granular materials with maximum particle diameter of 100mm and support both the load control and displacement control. The load cell is installed inside of triaxial cell and the axial displacement is measured locally in order to control and measure more accurately in the small strain level. The verification test of this testing system was carried out with urethane verification specimens. So, from now on the useful information for coarse granular materials are expected to suggested by performing many tests with various material and condition.

• Journal of Korean Society of Rural Planning
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• v.19 no.3
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• pp.195-203
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• 2013

This study aimed to plan a distinctive apple theme park, thereby specializing the nationwide brand of Cheongsong apple. Detailed objectives included: to establish the best possible environments in Korea to taste and appreciate apple and enjoy the Cheongsong Apple Festival; to identify and foster natural, cultural and social resources in the clean environment of Cheongsong; to clusterize research and production infrastructures for strengthening local competitiveness; and to develop a hub for the vitalization of the region where visitors and locals can mutually prosper. The study was multi-phased. The first stage included basic surveys such as local status and environment analysis and similar case studies, and the second stage was to review the appropriateness of theme selection, develop basic principles and strategies for development goals and review and incorporate project details. And the third stage aimed to develop a comprehensive plan from spatial plans and program plans and suggest plans to vitalize the operation of the park. The dimension of the subject site was $180,150m^2$, which was divided into four areas, in consideration of the land use and the environmental characteristics of the resources, for developing a land use scheme. The four areas were named: the apple-theme cultual area; the agricultural culture experience area; the plaza for exchange and harmony; and the plaza for natural observation. This study has significance in that it can serve as a case to develop farm theme parks, and as a case of appropriate development of programs to identify amenity resources with a focus on the existing resources and in consideration of local characteristics.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.449-459
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• 2017

In Geum River of Korea, three multi-purpose weirs were built at the downstream of Daecheong Reservoir during the Four Major River Restoration Project (FMRRP). The weirs have altered the hydraulic characteristics of the river, and consequently transformed the large areas of flowing ecosystem to deep and wide stagnant environment. In every summer, a thermal stratification occurred near the Baekje Weir having mean depth of 4.0 m, and the surface algal blooms dominated by buoyant cyanobacteria have been frequently formed after the FMRRP. The objective of this study was to investigate the relationship between flow velocity and thermal stability of the waterbody using a three-dimensional (3D) hydrodynamic model (EFDC+) after calibration against the thermistor chain data obtained in 2014. A new Sigma-Zed vertical grid system of EFDC+ that minimize the pressure gradient errors was used to better simulate the thermodynamics of the waterbody. The model reasonably simulated the vertical profiles of the observed water temperatures. The vertical mean flow velocity and the Richardson Number (Ri) that represents the stability of waterbody were estimated for various management water levels and flow rates scenarios. The results indicated that the thermal stability of the waterbody is mostly high ($Ri{\gg}0.25$) enough to establish stratification, and largely depend on the flow velocity. The critical flow velocity that can avoid a persistent thermal stratification was found to be approximately 0.1 m/s.

• Journal of Technologic Dentistry
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• v.27 no.1
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• pp.79-88
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• 2005

This study was performed to investigate the surface properties of electrochemically oxidized pure niobium by anodic oxide and hydrothermal treatment technique. Niobium specimens of $10\times10mm$ in dimension were polished sequentially from #600, #800, #1000 emery paper. The surface pure niobium specimens were anodized in an electrolytic solution that was dissolved calcium and phosphate in water. The electrolytic voltage was set in the range of 250 V and the current density was 10 $mA/cm^2$. The specimen was hydrothermal treated in high-pressure steam at 300$^{\circ}C$ for 2 hours using an autoclave. Then, specimens were immersed in the Hanks' solution with pH 7.4 at 37$^{\circ}C$ for 30 days. The surface of specimen was characterized by scanning electron microscope(SEM), energy dispersive X-ray microanalysis(EDX), potentiostat/galvanostat test, and cytotoxicity test. The results obtained was summarized as follows; According to the result of measuring corrosion behavior at 0.9% NaCl, corrosion resistance was improved more specimens treated with anodic oxide than in hydrothermal treated ones. The multi-porous oxide layer on surface treated through anodic oxidation showed a structure that fine pores overlap one another, and the early precipitation of apatite was observed on the surface of hydrothermal treated samples. According to the result of EDX after 30 days deposition in Hanks' solution, Ca/P was 1.69 in hydrothermal treated specimens. In MTT test, specimens treated through anodic oxidation and hydrothermal treated ones showed spectrophotometer similar to that of the control group. Thus no significant difference in cytotoxicity was observed (P>0.05).

• Journal of the Korean housing association
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• v.24 no.5
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• pp.9-16
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• 2013

The purpose of this study is to analyze local-based social welfare facilities to respond to secular change of the UR rental housing estates in Japan. The selected case studies for the analysis are Hibarigaoka, Hamakousien, Turumai UR rental housing estates constructed around 1960's. The analysis was done through UR website, MLIT (Ministry of Land, Infrastructure, Transport and Tourism) and MHLW (Ministry of Health, Labour and Welfare) policy report, and related literature. These case studies are connected with housing policy as well as welfare policy and performed to Stable Living Creation Project by Business Entry System for Stable Living. The types of local-based social welfare facilities are classified by welfare corporation and medical corporation. The results are as follows: 1) The implementation of cooperative and participative system not only the private sector (welfare and medical Corporation, etc.) but also the public (MLIT, MHLW, UR Renaissance Agency, Local government, etc.). 2) Repurposed of land through rent and transfer of land for local-based social welfare facilities in the process of housing stock renewal utilization. 3) The pursue of regional revitalization through attached to multi-generation facility or local community space for elderly in local-based social welfare facilities.

• Earthquakes and Structures
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• v.6 no.6
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• pp.647-664
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• 2014

A reduction of the response of irregular structures subjected to earthquake excitation by control devices equipped by suitable control algorithm is proposed in this paper. The control algorithm, which is used, is the pole placement one. A requirement of successful application of pole placement algorithm is a definition-selection of suitable poles (eigen-values) of controlled irregular structures. Based on these poles, the required action is calculated and applied to the irregular structure by means of control devices. The selection of poles of controlled irregular structure, is a critical issue for the success of the algorithm. The calculation of suitable poles of controlled irregular structure is proposed herein by the following procedure: a fictitious symmetrical structure is considered from the irregular structure, adding vertical elements, such as columns or shear walls, at any location where is necessary. Then, the eigen-values of symmetrical structure are calculated, and are forced to be the poles of irregular controlled structure. Based on these poles and additional damping, the new poles of the controlled irregular structure are calculated. By pole placement algorithm, the feedback matrix is obtained. Using this feedback matrix, control forces are calculated at any time during the earthquake, and are applied to the irregular structure by the control devices. This procedure results in making the controlled irregular structure to behave like a symmetrical one. This control strategy can be applied to one storey or to multi-storey irregular buildings. Furthermore, the numerical results were shown that with small amount of control force, a sufficient reduction of the response of irregular buildings is achieved.

• Information Systems Review
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• v.12 no.2
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• pp.105-119
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• 2010

SOA has become the focus of attention as it is perceived as a concept toward integrative service which helps companies respond quickly to the changes in market needs. This study is aimed to find out success factors for building SOA. We carried out two case studies on companies that adopted SOA successfully in Korea and conducted a survey to collect opinions from experts and experienced managers whose job is related to SOA. The critical successful factors found in this study include: 1) establishment of the SOA taskforce based on CIO's strong support, 2) formation of the corporate-wide consensus and the adoption of standards, 3) active user participation in defining services and obliterating duplication, 4) accomplishment of flexibility in services and business agility based on integrated infrastructure, and 5) securing project budget and consistent support by way of using measurement index for SOA investment effects.

• Journal of The Korean Association of Information Education
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• v.13 no.3
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• pp.393-400
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• 2009

As one of leading media converging broadcasting and telecommunications, IPTV is required to pursuit the idea of public interest from broadcasting industry and universal service from telecommunications industry as well as satisfying industrial effect. It needs to consider both industrial effect and public benefit when vitalizing IPTV services. The project of providing IPTV-based interactive public services is expected to enhance accessibility of public services, present shape of new public service in broadcasting-telecommunication convergence environment, resolve the shortage in contents supply which is one of most important problems in IPTV services. In this research understanding the overall response such as service usage status, satisfying/dissatisfying factor, trend of preference of the customer using IPTV-based interactive public services, we analyze what the public service mean in IPTV environment and public identity of IPTV. And we have investigate effective developing method and ripple effect of IPTV-based public services on broadcasting and telecommunications converged ecosystems.

• Land and Housing Review
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• v.8 no.4
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• pp.223-232
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• 2017

The purpose of this study is to identify the supply status and planning trend of North Korean housing through analysis on the North Korean architecture specialized media data. The flat composition is changing and the living room is becoming the center of the houses. Also, in the urban areas, the standard apartment type is four apartments in a row and the plan form is getting diversified into circle type, Y type, and irregular type. On the other hand, in the rural areas, two houses in a row and single house are typical and the change in planning scale and space structure are not substantial. Since the 2000s, design changes have been made to emphasize the third dimensional structure of buildings such as the elliptical houses and L-shaped houses. Furthermore, 8~10 households are located on one floor which leads to the tendency of the building enlargement. In terms of house size, a square concept was introduced to replace the initial 2~3 room concept and the basic module of the room planning the 3 room house based on $3m{\times}3m$. However, there seems to be no standard house size, and the house size may differ depending on the social classandregion. In the early 1980s, when there was focus on the apartment complex construction, the high-rise apartment buildings of 30~40 floors was planned. However, during the Pyongyang redevelopment project, apartments of more or less than 10 floors were built and row-houses of more or less than 4 floors were built. In terms of the complex scale, a lot of small complexes of around 300 households are emerging after 2010. The construction projects are mainly limited to specific regions such as Pyongyang and Samjiyeon, and also limited to specific classes such as the workers and soldiers initially and the scientists lately. In addition, living boundary composition and ancillary facilities for sufficient green area ratio securement and the people of North Korea are maintained consistently. In recent years, the specialized floor planning such as solar house and the house for the disabled people, framework houses for redevelopment business, and multi-storied house construction technology are also emerging.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.137-142
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• 2006

Cost and duration is important factors which directly affect profit therefore must be forecasted correctly to accomplish success of projects. So construction company uses EVMS(Earned Value Management System) to forecast final cost and duration. But previous forecasting model has low accuracy because of its linear forecasting method and can't reflect characteristic of company and project and changes as each progress. This paper presents cost and duration forecasting model using the slope prediction of cost and duration as each progress to reflect the various characteristics of construction industry. EVMS data of 23 road construction projects was used to make up regression analysis equation of slope forecasting model.