• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.117-125
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• 2016

Current cities encounter various types of water problems due to rapid urbanization and climate change. The increasing significance of urban water problems calls for the establishment of resilient alternatives to prevent and minimize social loss that results from these phenomena. As a background research for establishing resilient infrastructures for the mitigation of urban water problems, we evaluated the robustness of structural alternatives for urban flood as a representative case. Combining the robustness index (RI) and the cost index (CI), we suggested the robustness-cost index (RCI) as an indicator of the robustness of structural alternatives, and applied the index to assess the existing infrastructures and structural alternatives (i.e., sewer network expansion, additional storage tank construction, and green roof construction) at a site prone to floods located around Gangnam-station, Seoul, Korea. At a rainfall intensity frequency range of 2 to 20 years, the usage of a storage tank and a green roof showed relatively high RCI value, with a variation of an alternative showing greater RCI between the two depending on the size of design rainfall. For a rainfall intensity frequency of 30 years, installing a storage tank with some green roofing was the most resilient alternative based on the RCI value. We proposed strategies for establishing resilient infrastructures for the mitigation of urban floods by evaluating the robustness of existing infrastructures and selecting optimal structural alternatives with the consideration of scales of design disaster.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.1
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• pp.94-99
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• 2017

Breaking the rigid connection between the two faces of the wall can significantly improve the sound transmission loss of the wall. This is usually achieved by resiliently mounting the gypsum board on one of the two faces of the wall using resilient channel. Resilient channel with less stiffness than that of air cavity could move the resonance frequency of the light-weight wall. So we can get higher sound transmission loss at low frequencies for light-weight wall using resilient channel. It's sound transmission loss is 17 dB higher than that of single stud wall, and 5 dB higher than that of double stud wall.

• Journal of KIBIM
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• v.9 no.1
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• pp.32-41
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• 2019

As population in Sarasota and Manatee Counties, Florida in the United States is projected to increase, land use changes from land development happen continuously. The more land development means the more impervious surfaces and stormwater runoff to Sarasota Bay, which causes critical impact on the resiliency of the ecosystem. In order to decrease its impact on water quality and the ecosystem function of Sarasota Bay, it is important to assess the resilient status of communities that create negative impacts on the ecosystem. Three types of guiding principles of resiliency for Sarasota Bay watershed are suggested. To assess resiliency status, three indexes - vulnerability index, socio-economic index, and ecological index are developed and analyzed by using geographic information system for each census tract in the two counties. Since each indicator for vulnerability index, socio-economic index, and ecological index is measured with different metrics, statistical standardizing method - distance from the best and worst performers is used for this study to directly compare and combine them all to show total resilience score for each census tract. Also, the ten most and the ten least scores for the total resilience index scores are spatially distributed for better understanding which census tracts are most or least resilient. As Sarasota Watershed boundary is also overlaid, it is easy to understand how each census tract attains its resilience and how each census tract impacts to Sarasota Bay ecosystem. Based on results of the resiliency assessment several recommendations, guidelines, or policies for attaining or enhancing resiliency are suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.648-655
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• 2005

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the Engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.329-338
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• 2006

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode.

• Journal of Korean Society of Disaster and Security
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• v.9 no.1
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• pp.9-18
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• 2016

This research has been shown the systematic method about that the disaster resilient city make to certificate the UNISDR's role model city, the first case study in Korea, of that the Busan Geumjeong-gu city project to take part in and to lead the campaign of the 'Climate Change, the making resilient city' in Korea. For the making the life safety community, we research and analysis and apply the 10 Essentials and 41 Key Questions of the campaign making UNISDR's disaster resilient city, and check the disaster management items about the government and local ones ordering every years, and study to analyze the Geumjeong-gu factors about the seven checklists of life safety improvement, and educate and train and make the questionnaire for the safety campaign the citizen and volunteer in the 17 local areas, and show the vision and target, and 5 steps approaching strategy of 'Climate change, the making resilient city,'

• Steel and Composite Structures
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• v.52 no.3
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• pp.357-376
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• 2024

In this paper, weakly bonded ultra-high-strength steel bars (UHSS) were used as longitudinal reinforcement in recycled aggregate concrete shear walls to achieve resilient performance. The study evaluated the repairability and hysteresis performance of shear walls before and after retrofitting. Quasi-static tests were performed on recycled aggregate concrete (RAC) and steel fiber reinforced recycled aggregate concrete (FRAC) shear walls to investigate the reparability of resilient shear walls when loaded to 1% drift ratio. Results showed that shear walls exhibited drift-hardening properties. The maximum residual drift ratio and residual crack width at 1% drift ratio were 0.107% and 0.01mm, respectively, which were within the repairable limits. Subsequently, shear walls were retrofitted with bonded X-shaped CFRP strips and steel plates wrapped at the bottom and retested. Except for a slight reduction in initial stiffness, earthquake-damaged resilient shear walls retrofitted with a composite method still had satisfactory hysteresis performance. A revised damage assessment index D, has been proposed to assess of damage degree. Moreover, finite-element analysis for the shear wall before and after retrofit retrofitting was established in OpenSees and verified with experimental results. The finite element results and test results were in good agreement. Finally, parametric analysis was performed.

• Journal of the Korean Geotechnical Society
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• v.29 no.10
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• pp.67-74
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• 2013

The objective of this study was to identify the effect of engineering properties on the resilient modulus ($M_r$) of cohesive soils as subgrade. Eight representative cohesive soils representing A-6, and A-7-6 soil types collected from road construction sites, were tested in the laboratory to determine their basic engineering properties. The laboratory tests for the engineering properties were Atterberg limits test, sieve analysis, hydrometer test, Standard Proctor compaction test, and unconfined compressive strength test. Resilient modulus test and unconfined compressive strength test were conducted on unsaturated cohesive soils at three different moisture contents (dry of optimum moisture content, optimum moisture content, and wet of optimum moisture content). The increase in moisture content considerably affected the decrease in the resilient modulus. The resilient modulus increased with an increase in maximum unconfined compressive strength, percent of clay, percent of silt and clay, liquid limit and plasticity index. The resilient modulus decreased with an increase in percent of sand.

• Ecology and Resilient Infrastructure
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• v.5 no.2
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• pp.88-93
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• 2018

In-situ water quality sampling is used for accurate water quality assessment. However, in-situ water quality sampling offers limited samples and requires much time and intensive labors. Remote sensing approach has recently applied for water quality assessment. It has shown the advantage of offering a synoptic view but also more efficient and economical. In this study, we utilized Landsat Imagery to estimate the water quality of the Tamsui River basin, considered as one of the most important rivers located in the north of Taiwan. In order to monitor water quality of Tamsui River basin, a linear regression relation between the value of spectral radiance and four water quality parameters are investigated with 38 water sampling stations. Through the regression model, we could estimate river pollution index (RPI) from the predicted value of four water quality parameters. By using RPI, we can examine the pollution level of Tamsui River. The accuracy of RPI conversion of this study ranged from 32.2% to 68.2%.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.262-264
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• 2000

현재의 이동 컴퓨팅 환경은 더욱 보편화되고 있다. 그러나 베터리의 제약과 이동통신망의 높은 장애율로 사용에 불편을 느낀다. 여러 mobile client는 공통 관심이 있는 데이터를 서버로부터 받는 방법으로 broadcasting을 많이 쓰는데, 이때 indexing 기법을 이용해 클라이언트는 원하는 데이터를 filtering 해서 수신함으로서 에너지의 효율적 사용을 기할 수 있다. index를 중복시킴으로서 원하는 데이터의 access 시간을 줄이고 무선 통신망의 장애에 따른 성능 저하를 줄일 수 있다. 본 논문에서는 장애율에 따른 최적의 중복회수를 구하고 데이터 수신시 access 시간과 tuning 시간을 구한다.