• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.87-87
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• 2018

지난 30년간 한반도의 연평균 기온은 $1.2^{\circ}C$ 상승하여, 전세계 100년간 평균 기온 상승 $0.74^{\circ}C$에 비해 그 상승폭이 크게 증가하였다. IPCC 5차 평가보고서(2013년)의 RCP 시나리오에 따르면, 4차 평가보고서(2007년)의 SRES 시나리오에서 보다 우리나라의 기후변화 영향이 크게 증가될 것으로 예상하고 있으며, 2050년 연평균기온의 변화가 기존 $2.0^{\circ}C$에서 $3.2^{\circ}C$로, 강수량은 기존 11.5%에서 15.6%대로 증가할 것으로 전망하고 있다. 우리나라의 최근 10년간 발생한 자연재난을 살펴보면 호우, 태풍에 의한 피해가 가장 크게 나타났고, 대설, 강풍에 의한 피해가 뒤를 이었으며, 기후변화의 영향으로 재난 재해의 형태는 점차 대형화 다양화 되어가고 있다. 이러한 기후변화에 대비하여 효율적인 재난 대응 및 대책수립을 위해 재난 위험도 평가의 필요성이 증대되고 있으며 국내의 다양한 부처에서 연구를 수행하고 있다. 그러나 재난 위험도 평가체계 및 방법론이 각 연구별로 다원화되어 있고, 실무적용 또한 미흡한 실정이다. 따라서 본 연구에서는 UNISDR 등 국제기구에서 제시하는 위험도 평가방법론을 기반으로 우리나라에 적용 가능한 위험도 평가 방법론을 정립하고, 홍수, 태풍, 대설, 가뭄 등에 대한 재난 위험도 평가 기법을 개발하였다. 또한 실제 피해 통계와 평가 결과에 대한 비교 및 적정성 분석을 통해 우리나라 실정에 맞는 최적의 위험도 평가 체계 및 방법론을 구축하고자 하였다. 본 연구를 통해 위해성, 노출성, 취약성 및 저감능력 지표로 구성된 재난 위험도 평가 기법을 개발하였고, 재난 유형별 지역별 10단계, 5등급의 위험도 평가 결과를 도출하였다. 본 연구에서는 홍수, 태풍, 대설, 가뭄 등 6개 자연재난 유형에 대한 위험도 평가 지표를 개발하였으며, 향후, 국가 및 지역 재난안전관리계획에 자연재난 위험도 평가 결과 활용을 위해 후속 연구를 추진 중에 있다.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.44-54
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• 2012

In wireless sensor networks, a moving object tracking scheme is one of core technologies for real applications such as environment monitering and enemy moving tracking in military areas. However, no works have been carried out on processing the failure of object tracking in sparse sensor networks with holes. Therefore, the energy consumption in the existing schemes significantly increases due to plenty of failures of moving object tracking. To overcome this problem, we propose a novel moving object tracking scheme based on polynomial regression prediction in sparse sensor networks. The proposed scheme activates the minimum sensor nodes by predicting the trajectory of an object based on polynomial regression analysis. Moreover, in the case of the failure of moving object tracking, it just activates only the boundary nodes of a hole for failure recovery. By doing so, the proposed scheme reduces the energy consumption and ensures the high accuracy for object tracking in the sensor network with holes. To show the superiority of our proposed scheme, we compare it with the existing scheme. Our experimental results show that our proposed scheme reduces about 47% energy consumption for object tracking over the existing scheme and achieves about 91% accuracy of object tracking even in sensor networks with holes.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1530-1534
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• 2006

원격탐사 기법을 이용한 수심측정은 하나 혹은 그 이상의 파장대에서 수심과 반사되는 에너지 사이의 관계를 찾아내는데 달려 있다. 수심 정보를 획득하기 위한 스펙트럼의 최적 파장길이는 다중분광영상(Landsat 7 ETM)의 blue band에 해당하는 약 $0.48{\mu}m$이며, 이 band를 이용하여 연안의 수심을 측량하기도 한다. 하지만 단일밴드에 의해서 측정된 값을 이용한 수심측정은 해저표면에 의한 반사에 심각한 영향을 받을 수 있기 때문에 신뢰할 만한 결과를 얻을 수 없다. 따라서 본 연구에서는 해수와 관련한 여러 가지 변수들을 결정하기 위하여 다량의 실측 데이터를 필요로 하지 않는 선형다중밴드방식을 이용하여 2개의 Landsat 영상으로 태화강 하구의 수심정보를 추출하고 태화강 본류에 대한 수심정보획득과 하상변동에 대한 분석 가능성을 파악하였다. 그 결과 임의로 선정한 표본 50개 지점에 대한 영상분석에 의한 수심값과 해도의 수심값의 잔차 평균이 각각 2.29m, 2.43m로 비교적 큰 잔차를 보였다. 하지만 20m 미만의 수심대의 표본만을 확인한 결과 각각 1.73m, 1.88m로 잔차 평균이 크게 감소하였다. 2000년, 2003년 영상을 비교한 결과, 1번 2번 3번 지역에서 평균적으로 약 1.838m정도 2003년 수심이 감소한 것으로 나타났다. 본 연구에서 20m 미만의 수심 측량은 낮은 해상도의 위성영상이라도 실제 수심과 근접하고 있는 것으로 판단 할 수 있었다. 이것으로 넓은 지역을 경제적으로 수심자료를 획득할 수 있는 위성영상분석을 이용한 수심측정은 활용성이 있는 것으로 나타났다. 하지만 해저표면의 형태와 해수면의 상태 등 수심측정에 미치는 영향에 관한 실측데이터에 대한 자료수집과 분석이 선행된다면 더욱 좋은 결과를 도출할 수 있을 것으로 판단된다.A}$는 최대암모니아 섭취률을 이용하여 구한 결과 $0.65d^{-1}$로 나타났다.EX>$60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.101-115
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• 2005

For the site characterization at two inland areas, Gyeongju and Hongsung, which represent geomorphic and geologic characteristics of inland region in Korea, in-situ seismic tests containing borehole drilling investigations and resonant column tests were peformed and site-specific seismic response analyses were conducted using equivalent linear as well as nonlinear scheme. The soil deposits in Korea were shallower and stiffer than those in western US, from which the site coefficients and site classification system in Korea were derived. Most sites were categorized as site classes C and D based on the mean shear wave velocity $(V_s)$ of the upper 30 m $(V_s30)$, ranging between 250 and 650 m/s. According to the acceleration response spectra determined from the site response analyses, the site coefficients specified in the current Korean seismic design guide underestimate the ground motion in the short-period band and overestimate the ground motion in mid-period band. These differences can be explained by the differences in the bedrock depth and the soil stiffness profile between Korea and western US. The site coefficients, $F_a$ for short-period and $F_v$ for mid-period, were re-evaluated and the site classification system, in which sites C and D were subdivided according to $V_s20,\;V_s15,\;and\;V_s10$ together with the existing $V_s30$ was introduced accounting for the local geologic conditions at inland region of the Korean peninsula. The proposed site classification system in this paper is still rudimentary and requires modification.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.523-534
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• 2016

The purpose of this study is to develope a method for measuring social benefit by mitigating in-vehicle congestion level in intercity buses. Contingent valuation method and Tobit model are adopted for social benefit evaluation method. One thousand passengers were interviewed with 992 obtained valid samples. Tobit models with age, income level, and bus boarding times as explanatory variables are selected to estimate the willingness to pay for the mitigation of intercity bus in-vehicle congestion. Statistically and logically, two models with age or income level as explanatory variables are turned out to be valid. The intercity bus service supply status and usage are examined and the bus users who have willingness-to-pay for the intercity bus in-vehicle congestion mitigation have been identified. In case of the 'no standing' rules implemented to the intercity bus, the annual economic benefit from the service is estimated to be 14.7 billion won.

• Journal of the Korea Society of Computer and Information
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• v.29 no.11
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• pp.145-152
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• 2024

With the widespread adoption of smartphones, acquiring images has become easier. However, challenges arise due to uneven lighting conditions at night and the degradation and noise introduced during image transmission and compression. To minimize this noise and improve image quality, Non-Local Means (NLM) techniques are used, which unlike traditional methods, seek out patches within the image that are similar to the current patch to eliminate noise. However, a drawback of NLM is the diminishing utility as the similar patches become larger. This paper proposes a noise reduction method that utilizes the Sum of Absolute Differences to calculate similarity and applies weights accordingly. The proposed algorithm demonstrates an average improvement of 6.911dB in Peak Signal-to-Noise Ratio (PSNR) on Salt and Pepper noise images, showing a 0.713dB improvement over traditional NLM. When the proposed algorithm is applied to existing NLM optimization papers, performance improvements can be expected.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.170-176
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• 2005

This study was conducted to investigate the level of PCBs and distribution of PCB congeners in the ambient air of Korea and Japan. The source of PCBs were also studied by a statistical method. The TEQ concentration of PCB in the ambient air of Korea and Japan were between 0.003 and $1.01\;pgTEQ/m^3$(mean value : $0.22\;pgTEQ/m^3$) and between 0.002 and $0.014\;pgTEQ/m^3$ (mean value: $0.007\;pgTEQ/m^3$), respectively. The ambient air of industrial area of Korea showed a fluctuation in PCB concentration than other sampling area. The isomer distribution patterns in the ambient air was more or less similar in all sampling places. In addition, highly chlorinated homologues ($7{\sim}10CB$) were detected in the only Korea industrial area. This observation suggests that there is a possibility of specific source of PCBs in the industrial area. The source identification of PCB in ambient air was performed using multivariate statistical analysis(principal component analysis). As a result, it is estimated that the Korean ambient air was more influenced by combustion process than the ambient air of Japan and also the effect of PCB commercial products was relatively a small.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.203-218
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• 2010

The site categorization and corresponding site amplification factors in the current Korean seismic design guideline are based on provisions for the western United States (US), although the site effects resulting in the amplification of earthquake ground motions are directly dependent on the regional and local site characteristic conditions. In these seismic codes, two amplification factors called site coefficients, $F_a$ and $F_v$, for the short-period band and midperiod band, respectively, are listed according to a criterion, mean shear wave velocity ($V_S$) to a depth of 30 m, into five classes composed of A to E. To suggest a site classification system reflecting Korean site conditions, in this study, systematic site characterization was carried out at four regional areas, Gyeongju, Hongsung, Haemi and Sacheon, to obtain the $V_S$ profiles from surface to bedrock in field and the non-linear soil properties in laboratory. The soil deposits in Korea, which were shallower and stiffer than those in the western US, were examined, and thus the site period in Korea was distributed in the low and narrow band comparing with those in western US. Based on the geotechnical characteristic properties obtained in the field and laboratory, various site-specific seismic response analyses were conducted for total 75 sites by adopting both equivalent-linear and non-linear methods. The analysis results showed that the site coefficients specified in the current Korean provision underestimate the ground motion in the short-period range and overestimate in the mid-period range. These differences can be explained by the differences in the local site characteristics including the depth to bedrock between Korea and western US. Based on the analysis results in this study and the prior research results for the Korean peninsula, new site classification system was developed by introducing the site period as representative criterion and the mean $V_S$ to a depth of shallower than 30 m as additional criterion, to reliably determine the ground motions and the corresponding design spectra taking into account the regional site characteristics in Korea.

• Journal of Digital Contents Society
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• v.15 no.6
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• pp.663-673
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• 2014

The WBAN technology means a short distance wireless network which provides each device interactive communication by connecting devices inside and outside of body. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. Wireless body area network is usually configured in energy efficient using sensor and zigbee device due to the power limitation and the characteristics of human body. Wireless sensor network consist of sensor field and sink node. Sensor field are composed a lot of sensor node and sink node collect sensing data. Wireless sensor network has capacity of the self constitution by protocol where placed in large area without fixed position. In this paper, we proposed the efficient addressing scheme for improving the performance of routing algorithm by using ZigBee in WBAN environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. Therefore proposing x, y and z coordinate axes from divided address space of 16 bit to solve this problems. Each node was reduced not only bitwise but also multi hop using the coordinate axes while routing than Cskip algorithm. I compared the performance between the standard and the proposed mechanism through the numerical analysis. Simulation verified performance about decrease averaging multi hop count that compare proposing algorithm and another. The numerical analysis results show that proposed algorithm reduced the multi hop better than ZigBee distributed address assignment

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.614-624
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• 2013

The purpose of this study is to offer the raw data for establishing the plan of disaster prevention and the continuous conservation of soil ecosystem by grasping the potential soil loss and the danger of erosion using RUSLE method on whole districts in Gyeongju National Park, Korea. In the results of the average amount of soil erosion for the year, the average of all districts was 5.7 ton/ha in annual, and Namsan district was the highest in 7.6 ton/ha in annual and Seoak district was the lowest in 2.1 ton/ha in annual. The dangerous district due to the soil erosion was analyzed as under 1%, and Gumisan and Hwarange district was not serious. But Namsan district was higher than others, especially, there was intensive in all over Geumohbong. Therefore, to protect the all over Geumohbong, we will establish the valid of restoration and management. The types of land cover in Gyeongju National Park mostly showed forest, and as the average amount of soil erosion in forest was 3.7 ton/ha in annual, there was good condition. In the results of the amount of soil erosion due to landform, the deep canyon showed as 7.3 ton/ha in annual per unit area, secondly, the U-shaped valley was analyzed as 6.1 ton/ha in annual. The plain and high ridge were predicted that there occurred the small amount of soil erosion. In future, if we will analyze the amount of soil erosion in Korean National Parks, we will offer the help to establishing the plan of conservation and restoration on soil ecosystem in whole National Parks.