• 대한원격탐사학회지
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• 제35권4호
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• pp.617-623
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• 2019

Numerous water disasters have recently occurred all over the world, including South Korea, due to global climate change in recent years. As water-related disasters occur extensively and their sites are difficult for people to access, it is necessary to monitor them using satellites. The Ministry of Environment and K-water plan to launch the next-generation medium satellite No. 5 (water resource/water disaster satellite) equipped with C-band synthetic aperture radar (SAR) in 2025. C-band SAR has the advantage of being able to observe water resources twice a day at a high resolution both day and night, regardless of weather conditions. Currently, RADARSAT-2 and Sentinel-1 equipped with C-band SAR achieve the purpose of their launch and are used in various environmental fields such as forest structure detection and coastline change monitoring, as well as for unique purposes including the detection of flooding, drought and soil moisture change, utilizing the advantages of SAR. As such, this study aimed to analyze the characteristics of the next-generation medium satellite No. 5 and its application in environmental fields. Our findings showed that it can be used to improve the degree of precision of existing environmental spatial information such as the classification accuracy of land cover map in environmental field works. It also enables us to observe forests and water resources in North Korea that are difficult to access geographically. It is ultimately expected that this will enable the monitoring of the whole Korean Peninsula in various environmental fields, and help in relevant responses and policy supports.

• 대한원격탐사학회지
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• 제38권5_3호
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• pp.887-899
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• 2022

기상학적 요인에 의해 발생하는 가뭄은 육상 생태계의 식생에 부정적인 영향을 미친다. 본 연구에서는 기상학적 가뭄이 식생에 영향을 미치는 상태를 식생의 생태가뭄으로 정의하고, 영향 정도를 정량적으로 감시하기 위한 식생의 생태가뭄 상태지수(ecological drought condition index of vegetation, EDCI-veg)를 제안하였다. EDCI-veg는 식생과 기상학적 가뭄 정보 사이의 copula 기반의 이변량 결합확률모델로부터 도출되며, 가뭄이 발생했을 때 현재의 식생 상태가 가뭄으로 인해 얼마나 영향을 받았는지를 수치로 표현할 수 있다. 과거의 기상학적 가뭄 사상과 그에 대응하는 식생 상태를 비교하여 제안된 지수를 살펴본 결과, EDCI-veg는 식생의 생태가뭄을 적절하게 모니터링할 수 있음이 확인되었다. 또한, 원격탐사자료를 활용하여 고해상도의 가뭄 지도를 작성함으로써 생태가뭄 상태를 공간적으로 식별할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.52-55
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• 2006

It's used to be said that tsunami is a rare event. The recurrence time of tsunami in Sumatra area is approximately 230 years as CalTech Research Group‘s study from paleocoral. However, the tsunami occurred in Indian Ocean on 26 December 2004, 28 March 2005 and 17 July 2006, because the earthquakes still release the energy. To cope with the tsunami disaster, we have to put the much effort on better disaster preparedness. The Tsunami Reduction Of Impacts through three Key Actions (TROIKA) was suggested by Eddie N. Bernard, the director of NOAA/PMEL (Pacific Marine Environmental Laboratory). They are Hazard Assessment, Mitigation and Warning Guidance. The satellite remote sensing has potential on these actions. The medium and high resolution satellite data were used to assess the degree of damage at the six-damaged provinces on the Andaman seacoast of Thailand. Fast and reliable interpretation of the damage by remote sensing method can be used for inundation mapping, rehabilitation and housing plans for the victims. For tsunami mitigation, the satellite data can be used with GIS to construct the evacuation map (evacuation route and refuge site) and coastal zone management. It is also helpful for educational program for local residents and school systems. Tsunami is a kind of ocean wave, therefore any satellite sensors such as SAR, Altimeter, MODIS, Landsat, SPOT, IKONOS can detect the tsunami wave in 2004. The satellite images have shown the characteristics of tsunami wave approaching the coast. For warning, satellite data has potential for early warning to detect the tsunami wave in deep ocean, if there are enough satellite constellation to monitor and detect the first tsunami wave like the pressure gauge, seismograph and tide gauge with the DART buoy can do. Moreover, the new methods should be developed to analyse the satellite data more faster for early warning procedure.

• 농업과학연구
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• 제46권3호
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• pp.661-670
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• 2019

In this study, we constructed a model of an area where the production and production amount of wild vegetables which are designated as short term income forest products for the whole country are self-sufficient for the representative Eastern Braken fern(Pteridium aquilinum)and Edible aster(Aster scaber). The difference between the existing cultivation site and the model result was examined, and the distribution of the cultivable area was simulated according to the near future climate change by the 2050s. The degree of agreement between the cultivated area and the actual native area was very low at 14.5% for Eastern Braken fern and 12.9% for Edible aster. Using the Maxent model, which has already been proven by many research examples, the cultivation maps through the model can guarantee statistical accuracy by considering many variables. To analyze future location changes, the RCP 4.5 scenario and the RCP 8.5 scenario were applie Edible aster d to predict potential future cultivable areas and compare them to the present. There was no decrease in the cultivable area due to climate change nationwide. However, in the RCP 8.5 scenario for Eastern Braken fern and the RCP 4.5 scenario for Edible aster, declining areas such as Gangwon-do, Jeollabuk-do and Gyeongsangbuk-do showed prominence according to the scenarios. The result of this study suggests that various models can be used for the production of short-term forest productivity maps and it will be used as a climate change impact assessment data for competitive forest products considering the influence of future climate change.

• 한국콘텐츠학회논문지
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• 제14권10호
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• pp.454-462
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• 2014

최근 위치 측정 기술과 모바일 기기들의 발달과 함께 위치 기반 서비스가 중요하게 연구되고 있다. 위치기반서비스를 제공하기 위해 많은 연구자들이 맵리듀스를 활용한 다양한 질의 처리 기법을 제안하였다. 그 중에 하나가 맵리듀스를 활용한 리버스 k-최근접 질의 처리 기법이다. 하지만 기존 기법들은 연속 리버스 k-최근접 질의 처리를 수행하기 위해 많은 처리 비용이 요구된다. 본 논문에서는 맵리듀스를 활용한 효율적인 연속 리버스 k-최근접 질의 처리 기법을 제안한다. 제안하는 기법은 60도 가지치기 기법을 이용한다. 제안하는 기법은 60도 가지치기 기법을 활용하여 모니터링 영역을 생성하고 모니터링을 수행하여 결과 업데이트을 수행하기 때문에 효율적으로 결과 업데이트를 수행한다. 또한, 본 논문에서는 제안하는 기법의 우수성을 보이기 위해 기존 기법과의 성능평가를 수행한다.

• 대한불안의학회지
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• 제10권2호
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• pp.143-150
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• 2014

Objective : The subgenual cingulate cortex, a part of default-mode network, has been known to playa key role in the pathophysiology of depression. The previous studies have reported abnormal functional connectivity between the subgenual cingulate cortex and other brain regions in the patients with depression. The goal of this shldy was to explore the resting-state functional connectivity of the subgenual cingulate cortex between the patients with depression and healthy subjects. Methods : Twenty patients with major depression and age- and sex-matched 20 healthy subjects underwent 5-minute resting state fMRI scans. The functional connectivity map in each subject was acquired using seed-based correlation analysis with the seed located in the subgenual cingulate cortex (Talairach coordinates; x=-10, y=5, z=-10). The functional connectivity maps were calculated using AFNI and compared between the patient and healthy subject group via two-sample T-test using 3dttest++ in AFNI package. Results : Functional connectivity was decreased between the subgenual cingulate cortex and both sides of fusiform gyrus in depressed subjects. Connectivity was also decreased between the subgenual cingulate cortex and the left cerebellum in the patient group. There was no correlation between the severity of depression and the degree of functional connectivity between the subgenual cingulate cortex and the regions showing decreased functional connectivity. Conclusion : Decreased resting-state functional connectivity between the subgenual cingulate cortex and both sides of fusiform gyrus, and decreased connectivity between the subgenual cingulate cortex and the left cerebellum found in the patients with major depression in comparison to the healthy subjects might be related to abnormal emotional and cognitive processing of depressed patients.

• 한국환경과학회지
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• 제12권6호
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• pp.573-582
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• 2003

According to the survey map, the altitudes of up and down the Ansungchon were 242m and 49m accordingly. The width of the river was 4m at upperstream and became wider, lam at midstream and 114m at downstream. Water pH of the Ansungchon was measured variously in the range of 6.0-7.9 according to the surveyed times and areas. The water pH measured during June through August decreased continually and suddenly increased at the end of October. Phragmites iaponica, a major species of the fresh water emergent anchored hydrophytes, was surveyed mostly in the area of upperstream, Phragmites communis, Miscanthus sacchariflorus and Typha orientalis were surveyed in the areas of midstream and downstream, and Zizania latifolia was found in all areas of the river. The total of 101 taxa dividing into 32 families, 71 genera, 88 species, and 13 varieties have been inhabited in these areas. Among the inhabited plants, Poaceae was 21.8%, which appeared in the highest percent. Compositae was 20.8%, and Polygonaceae was 11.9%. In the surveyed areas, herbaceous plants were 95.1% and mostly occupied, and woody plants were 4.9％. Among the herbaceous plants, perennial plants were 52.5%, and annual and biannual plants were 28.7% and 13.9% accordingly. Naturalized plants dividing into 8 families and 18 genera have been found in the surveyed areas. The number of the naturalized plants increased from upperstream to downstream as the environmental disruption became worse. Only 2.5% of the total naturalized plants were appeared in up, 17.7% in midstream, and 28.6% in downstream. Shannon-Weiner's index for the degree of diversity was 2.898-3.666 in the area of upperstream, but 3.708-4.135 in downstream, which was little higher.

• 비파괴검사학회지
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• 제30권5호
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• pp.429-436
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• 2010

최근에는 T-ray(terahertz ray)를 이용한 비파괴기술이 새로운 분야로 주목을 받고 있다. 본 연구에서는 FRP 복합재료의 내재결함이나 레이업(lay-up) 특성을 검사 및 평가하기 위한 T-ray 시간영역 분광기(time-domain spectroscopy)를 활용하였으며 또한 이 T-ray 분광기의 일반적인 반사 및 투과모드를 이용하여 T-ray 이미지를 구현하였다. 특히, 2개의 톱날 인공결함이 내재한 GFRP 복합재의 평가방법을 제시하였다. CFRP 복합재료에 대해서는 T-ray 전파는 탄소섬유로 인해 진행 장해를 받는다. 이에 따라 T-ray의 전기장(E-field)의 방향과 탄소섬유 방향의 의존성을 분석하였다. 한편 인공결함인 알루미늄 테이프, 박리, 충격손상, 이물혼입 등을 T-ray를 이용하여 비파괴 검사 및 평가하였다. 이를 통해 FRP 복합재료의 T-ray비파괴평가의 적용 가능성 및 한계 등을 확인 할 수 있었다.

• 한국지리정보학회지
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• 제13권1호
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• pp.89-100
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• 2010

본 연구는 다양한 고해상도 위성영상을 사용하여 토지피복도를 제작하고 영상종류와 피복도의 분류에 따른 정확도를 비교함에 목적이 있다. 토지피복도 작성시 세분류의 다양함을 위해 시가지와 농지, 수역 등을 포함하는 낙동강 하구 일대를 연구지역으로 선정하였고, 1m 이상의 해상도를 가지는 KOMPSAT2, QuickBird, IKONOS, 항공사진등을 육안판독 후 분류 하였다. 영상과 피복분류에 따른 토지피복도를 작성 후 상호 비교 한 결과 영상별 정확도는 항공사진과 QuickBird가 KOMPSAT2와 IKONOS 보다 상대적으로 높은 것으로 나타났고, 분류방법에 따른 일치도는 대분류의 경우 0.934~0.956, Kappa value는 0.905~0.937, 중분류의 일치도는 0.888~0.913, Kappa value는 0.872~0.901, 세분류의 일치도는 0.833~0.901, Kappa value는 0.813~0.888로 나타났다. 또한 영상별 혼돈발생 정도는 분류 항목에 따라 대분류의 경우 시가화 건조지역과 나지의 혼돈이 발생했고, 중분류는 논, 밭, 하우스 재배지, 인공초지에서 주로 발생하며, 세분류의 경우 자연녹지, 시설물 경작지, 간석지와 해수면으로 주로 나타났다. 본 연구를 통해 토지피복도 작성시 육안판독에 의한 고해상도 영상분류는 전체 80% 이상의 일치도를 나타내어 활용이 가능했고, 고해상도 영상을 사용할수록 정확한 분류가 가능하며 영상의 촬영시기가 토지피복도 작성에 중요함을 알 수 있었다.

• 한국환경복원기술학회지
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• 제10권2호
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• pp.97-104
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• 2007

A/R CDM(Afforestation/Reforestation Clean Development Mechanism) in Kyoto Mechanism means, either afforestation in the area used for other purposes more than 50 years or reforestation in the area used for other purposes on December 31st in 1989. South Korea has few sites due to the successful forestation in the past, but North Korea has not reforested the deforested lands since the mid-1970's. So these areas need to apply A/R CDM Project for restoration. The purposes of this study are to make a time series analysis in deforested areas and to estimate a feasibility of A/R CDM. To find the site satisfying A/R CDM business definition, land cover classification was applied using satellite images of the mid-1970's with good forestation, late 1980's including A/R CDM base year, and recent 2000's, and the chronological change was analyzed to categorize the possible sites. The North Korean topographical map of 1977 was used to verify land cover classification degree of 1970's, the land cover classification results made by the Ministry of Environment in 2000 were compared to verify the accuracy of 1980's results, and the land cover classification results in 2000's were verified by 2 site visits. The results of this study can be summarized as follows. The eligible A/R CDM sites are 605,156ha on the basis of the forestation change analysis in North Korea. Since the mid-1970's, 30.8% of the decreased forestation area of 1,966,306ha was classified into A/R CDM eligible sites. While other countries have the limited eligible sites, which has not been used for forestation since 1989 or which is being scattered, North Korea has large scale sites. Deforested sites are mainly around road and residential area, consequently give better accessibility for forestation than other countries. In conclusion, it is found that North Korea can provide efficient site for applying A/R COM Project to forestation restoring deforested land because of easy accessibility and existence of many possible sites due to artificial deforestation. Also, it is meaningful that the study suggests the application possibility of A/R COM Project to restore deforested land in North Korea and the related basic information through the chronological classification of the mid-1970's with good forestation, the late-1980's including A/R COM base year, and recent 2000's. It is expected that the study contributes to revitalization of A/R CDM Project and related research on North Korea forestation.