• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.458-463
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• 2005

OFDM communication system is effective for the high data rate transmission in the frequency selective fading channel. Since OFDM has high PAPR, OFDM signal may be distorted by the nonlinear HPA. In this paper, we propose an combined SLM and PTS method for reducing the PAPR in OFDM communication system. Proposed method increased some system complex in comparison with exiting method. But we made sure of high efficiency in the case of reducing the PAPR. As a result of using the 16-QAM modulation and increasing the carrier number in the SLM, PTS method and the SLM-PTS combined method, SLM-PTS combined method is more an effective method of reducing 3.5 dB PAPR than exiting OFDM system when this method is M, L=3, D=128, 256 in 10-3 BER.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.358-358
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• 2021

자연재해 중 홍수는 전 세계적으로 가장 큰 인적 및 물적 피해를 발생시키고 있으며, 지구온난화로 가속화되고 있는 기후변화는 더욱 극심한 호우와 태풍 현상을 야기하고 있다. 최근 우리나라에서도 2020년 장마는 역대 가장 긴 장마로 기록되는 등 변화된 기상현상으로 인해 홍수피해의 빈도와 강도가 지속적으로 증가하고 있다. 따라서, 이상기후로 인한 홍수피해에 대한 대비와 적응을 위해 위험도 평가, 예·경보시스템, 대피체계 등과 같은 비구조적 대책의 수립이 필요하다. 그 중 홍수피해에 대한 위험도 평가는 과거 홍수피해자료를 바탕으로 지역별 피해양상이나 상대적인 피해위험도를 파악할 수 있으므로 홍수피해 저감대책 수립에 중요한 비구조적 도구로 인식되고 있다. 이에 따라 본 연구는 행정구역별 과거 강우특성 및 홍수피해자료를 분석하여 강우조건에 따라 예상되는 홍수피해위험도를 평가하는 방법을 제안하고자 한다. 이를 위해 먼저, 국민재난안전포털에서 제공하는 재해연보에서 행정구역별 최근 20년 동안의 호우 및 태풍으로 인한 피해자료를 수집하여 인적 및 물적 피해특성 자료를 구축하고, 홍수피해가 발생한 기간에 대해 기상청에서 제공하는 시강우량 자료를 수집하여 홍수피해 사상별 다양한 강우특성자료를 구축한다. 구축된 자료를 이용하여 행정구역별 강우-피해 상관분석을 수행하고, 회귀분석 과정에서 이상치가 존재할 경우 회귀모형의 적합도를 향상시키기 위해 이상치를 제거하고 분석하여, 회귀식의 결정계수 및 유의성 검정결과를 바탕으로 3가지 원인별(호우, 태풍, 종합), 2가지 홍수피해별(인적, 물적) 강우-피해 최적 회귀함수를 선정한다. 최종적으로 강우조건에 따른 홍수피해 규모를 예측하고, 이를 통하여 행정구역별 상대적인 홍수피해위험도를 평가한다. 본 연구를 통해 행정구역별 강우조건에 따른 예상 홍수피해위험도를 분석하여 홍수피해에 대한 저감대책 수립에 기초자료를 제공할 수 있을 것으로 기대된다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.311-314
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• 2008

While relevant fields of construction industry have rapidly changed, the adaptation (skill) level of individuals to apply or utilize them has slowly followed. By understanding how individuals resist and conform under this change of construction industry and which factors are important for the adaptation, much time, effort, and cost can be saved for organization operation and management, and these saved resources will be able to be effectively invested to others. Accordingly, for construction industry it is necessary to understand and study how the users fit into the rapid technological change. Through this research, therefore, a systematic guideline should be created for the relevant fields of construction industry. For this research, the characteristics of individual personalities and behaviors based on the traditional model was observed and factors that contribute to the resistance and their mutual relations were theoretically identified and categorized, and then a conceptual and figurative model to show the mutual relation between the identified resistive factors was suggested.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.516-516
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• 2017

기후변화로 인하여, 홍수, 사막화, 엘니뇨 등의 자연재해가 이전보다 더 발생하고 있다. 기후변화 적응은 전 세계적으로 기후변화 대응보다 중요해지고 있다. 기후변화 적응을 위한 이슈 중 하나가 물 순환이다. 각 국가에서는 물 순환을 활성화하기 위한 기술을 개발하고 있다. 특히, 저영향개발(LID, Low Impact Development)이라는 물을 확보하기 위한 정책이 각 국가별로 추진되고 있으며, 이에 따른 기술이 개발되고 있다. 국내에서도 2001년에 국토해양부는 수자원장기종합계획을 발표하고, 환경부에서는 2013년에 LID기술요소 가이드라인과 환경영향평가 시 적용 가능한 저영향개발 매뉴얼을 개발하는 등 LID기술을 개발하고 적용하기 위한 정책을 펼치고 있다. 이러한 LID기술 중 하나가 빗물 집수시스템이며, 이 빗물집수시스템은 주거지역에서 빗물을 배수하고, 집수하여 빗물을 이용하기 위해 적용되고 있다. 현재 적용되고 있는 빗물 집수시스템은 측구 집수시스템과 원형 집수시스템이 있으며, 최근에는 수로형 집수시스템이 적용되는 지역도 있다. 본 연구에서는 전과정 평가(LCA, Life Cycle Assessment)를 이용하여 빗물 집수시스템의 환경성을 평가하고자 한다. 현재, 국내에서는 녹색건축물인증, 탄소성적 표지인증, 환경성적 표지인증 등 LCA를 이용하여 환경성을 평가하고 있다. 특히, 본 연구에서는 기후변화 측면에서 LCA를 적용하여 이산화탄소배출량을 평가하고자 하였다. 본 연구의 범위는 빗물집수시스템 30m로 가정하였으며, 측구 집수시스템, 원형 집수시스템 및 수로형 집수시스템의 건설, 운영 및 유지관리, 해체 및 폐기단계의 전 과정이다. 각 빗물 집수시스템에 대해 각 단계별로 이산화탄소 배출량을 산정한 결과, 수로형 집수시스템은 $2.82\;ton\;CO_2\;eq./set$이며, 원형 집수시스템은 $27.65\;ton\;CO_2\;eq./set$, 측구 집수시스템은 $21.54\;ton\;CO_2\;eq./set$이 배출되었다. 이산화탄소배출량 측면에서는 수로형 집수시스템이 나머지 두집수시스템보다 87~90%가 저감되는 것으로 나타났다. 본 연구는 저영향개발에 대응하는 동시에 기후변화를 대응한다는 측면에서 빗물 집수시스템 정책에 활용되고, 설계시에도 반영될 수 있을 것으로 사료된다. 추가적으로 이산화탄소뿐 만 아니라, 다른 환경성을 평가하는 연구가 진행될 필요가 있다.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.154-165
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• 2016

Recently, the frequency of extreme rainfall event has increased due to climate change and impermeable area also has increased due to rapid urbanization. Therefore, we ought to prepare countermeasures for flood reduction to reduce the damage. To consider climate change, the frequency based rainfall was calculated according to the aimed period(reference : 1971~2010, Target period I : 2011~2040, Target period II : 2041~2070, Target period III : 2071~2100) and the flood discharge was also calculated by climate change using HEC-HMS model. Also, the flood elevation was calculated by each alternative through HEC-RAS model, setting 5 sizes of drainage pumps and reservoirs respectively. The flood map was constructed using topographical data and flood elevation, and the economic analysis was conducted for reduction of flood damage using Multi dimension - Flood Damage Analysis, MD-FDA. As a result of the analysis on the flood control effect, a head of drainage pump was reduced by 0.06m up to 0.44m while it was reduced by 0.01m up to 1.86m in the case of a detention pond. The flooded area shrunk by up to 32.64% from 0.3% and inundation depth also dropped. As a result of a comparison of the Benefit/Cost index estimated by the economic analysis, detention pond E in period I and pump D in period II and III were deemed appropriate as an alternative for climate change. The results are expected to be used as good practices when implementing the flood control works considering climate change.

• Korean Journal of Construction Engineering and Management
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• v.18 no.2
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• pp.81-90
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• 2017

In Imjin River basin, three floods occurred between 1996 and 1999, causing many casualties and economic losses of 900 billion won. In Korea, flood damage is expected to increase in the future due to climate change. This study used the climate scenarios to estimate future flood damage costs and suggested a real options-based economic assessment method. Using proposed method, the flood control infrastructures in Imjin River basin were selected as a case study site to analyze the economic feasibility of the investment. Using RCP (Representative Concentration Pathway) climate scenarios, the future flood damage costs were estimated through simulated rainfall data. This study analyzed the flood reduction benefits through investment in the flood control infrastructures. The volatility of flood damage reduction benefits were estimated assuming that the RCP8.5 and RCP4.5 climate scenarios would be realized in the future. In 2071, the project option value would be determined by applying an extension option to invest in an upgrading that would allow the project to adapt to the flood of the 200-year return period. The results of the option values show that the two investment scenarios are economically feasible and the project under RCP8.5 climate scenario has more flood damage reduction benefits than RCP4.5. This study will help government decision makers to consider the uncertainty of climate change in the economic assessment of flood control infrastructures using real options analysis. We also proposed a method to quantify climate risk factors into economic values by using rainfall data provided by climate scenarios.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.92-104
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• 2017

Previous management for speed in road traffic system was aimed only to the improvement of mobility and safety. However, consideration for the aspect of environment and energy consumption efficiency was valued less than the former ones. Nevertheless, economical damage scope caused by climate change has been increasing and it is estimated that environmental value will be increased because of the change of external circumstances. In addition, policy for reducing carbon emission in transportation system was assessed as insufficient in improving the condition of traffic road since it only focused on the transition of private vehicle into public transportation and development of eco-friendly car. Now it is the time to prepare for the adaptation strategy and precaution for the increased number of private vehicle in Korea. For this, paradigm shift in traffic operation which includes the policy not only about the mobility but also about caring environment would be needed. It is needed to be able to monitor the actual amount of greenhouse gas in real time to reduce the amount of emitted greenhouse gas in the aspect of traffic management. In this research, a methodology which can build on-line greenhouse gas emission monitoring system by using real time traffic data and predicting the circumstance in next 5 minutes was suggested.

• Journal of Environmental Policy
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• v.13 no.3
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• pp.43-73
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• 2014

Cities in Korea have rapidly urbanized and they are not well prepared for natural disasters which have been increased by climate change. In particular, they often struggle with urban flooding. Recently, green infrastructure has been emphasized as a critical strategy for flood mitigation in developed countries due to its capability to infiltrate water into the ground, provide the ability to absorb and store rainfall, and contribute to mitigating floods. However, in Korea, green infrastructure planning only focuses on esthetic functions or accessibility, and does not think how other functions such as flood mitigation, can be effectively realized. Based on this, we address this critical gap by suggesting the new green infrastructure planning framework for improving urban water cycle and maximizing flood mitigation capacity. This framework includes flood vulnerability assessment for identifying flood risk area and deciding suitable locations for green infrastructure. We propose the use of the combination of frequency ratio model and GIS for flood vulnerability assessment. The framework also includes the selection process of green infrastructure practices under local conditions such as geography, flood experience and finance. Finally, we applied this planning framework to the case study area, namely YeonJe-gu an Nam-gu in Busan. We expect this framework will be incorporated into green infrastructure spatial planning to provide effective decision making process regarding location and design of green infrastructure.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.1
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• pp.42-53
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• 2021

Street trees improve the cityscape and air quality, reduce heat islands, and create wildlife habitats. Hence, they are essential parts of a city's green infrastructure. Therefore, several trees that are well adapted to the urban environment were planted. However, this caused the problem of simple trees being planted around the world. This study is to select more various street trees. To accomplish this, evaluation criteria and detailed indexes were created. The importance was indicated through the Analytic Hierarchy Process. For commercial roads, the priority of landscape characteristics is 0.2640, and among detailed indicators, the priority of shape is 0.1245. For work roads, the priority of landscape characteristics is 0.2496, and among detailed indicators, the priority of shape is 0.1177. For work roads, the priority of characteristics of civil service is 0.2250, and among detailed indicators, the priority of shape is 0.1177. For general roads, the priority of maintenance characteristics is 0.2479, and among detailed indicators, the priority of shape is 0.1062. For historical and cultural roads, the priority of regional characteristics is 0.3488, and among detailed indicators, the priority of regional characteristics is 0.1643. For ecological roads, the priority of ecosystem characteristics is 0.3488, and among detailed indicators, the priority of the diversity of species is 0.1643. For automotive-only roads, the priority of the ecosystem characteristics is 0.4639, and among detailed indicators, the priority of reducing emissions is 0.1643. This study will provide objective criteria for the selection of street trees.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.615-626
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• 2013

In this study, spatial patterns of the urban flood vulnerability index in Seoul are examined by considering climate exposure, sensitivity, and adaptability associated with floodings for recent 5 year (2006~2010) period by the smallest administrative unit called Dong. According to the results of correlation analyses based on the IPCC(Intergovernmental Panel on Climate Change)'s vulnerability model, among many variables associated with urban flooding, rainwater tank capacity, 1-day maximum precipitation and flood pumping station capacity have statistically-significant, and relatively-high correlations with the number of flood damage in Seoul. The flood vulnerability map demonstrates that the extensive areas along Anyang and Joongnang streams show relatively high flood vulnerability in Seoul due to high sensitivity. Especially in case of Joongnang stream areas, climatic factors also contribute to the increase of flood vulnerability. At local scales, several Dong areas in Gangdong-gu and Songpa-gu also show high flood vulnerability due to low adaptability, while those in Gangnam-gu do due to high sensibility and climate factor such as extreme rainfall events. These results derived from the flood vulnerability map by Dong unit can be utilized as primary data in establishing the adaptation, management and proactive policies for flooding prevention within the urban areas in more detail.