• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.31-38
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• 2010

Environment and climate changes affect all aspects of our society. The enhanced remote sensing technology made the satellite to be widely used in the environment monitoring applications. Geostationary environmental monitoring is also actively researched due to the increased needs for the monitoring of diurnal environmental changes, troposhperic pollution and its origin. In this paper, recent development trends of geostationary environment monitoring payloads are introduced. GEO-CAFE and GIFTS missions are researched by the leading of the NASA and Sentinel-4 by the ESA. Those missions are in the state of detailed conceptual design and hardware development preparing with the launch plan in the late 2010s. By considering these development trends, domestic environment monitoring payloads shall be developed with careful analysis on the mission and data application.

• Korean Journal of Remote Sensing
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• v.33 no.6_3
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• pp.1179-1185
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• 2017

The KOMPSAT-3A satellite acquires high-resolution MWIR images twice a day compared to conventional Earth observing satellites. New radiometric information of Earth's surface can be provided due to different characteristics from existing SWIR images or TIR images. In this study, the difference image of multitemporal images was generated and compared with existing infrared images to find the characteristics of KOMPSAT-3A MWIR satellite images. A co-registration was performed and the difference between pixel values was minimized by using PIFs (Pseudo Invariant Features) pixel-based relative normalization. The experiment using Sentinel-2 SWIR image, Landsat 8 TIR image, and KOMPSAT-3A MWIR image showed that the distinction between artifacts in the difference image of KOMPSAT-3A is prominent. It is believed that the utilization of KOMPSAT-3A MWIR images can be improved by using the characteristics of IR image.

• Environmental Engineering Research
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• v.11 no.5
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• pp.277-284
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• 2006

The genetic toxicity of environmental pollutants, namely, nonylphenol (NP), bisphenol A (BPA) and chloropyriphos (CP) was investigated in aquatic sentinel species, freshwater crustacean, Daphnia magna, and larva of aquatic midge, Chironomus tentans, using Comet assay. Physiological effect of such pollutants was also investigated by studying the specimens' rates of reproduction, growth and survival. Acute toxicity results showed that, as expected, Daphnia was more sensitive than Chironomus to chemical exposure. The order of acute toxicity was CP > NP > BPA in D. magna and NP > CP > BPA in C. tentans. BPA may exert a genotoxic effect on D. magna and C. tentans, given that DNA strand breaks increased in both species exposed to this compound, whereas NP- and CP-induced DNA damage occurred only in C. tentans. In vivo genotoxic data obtained in aquatic sentinel species could provide valuable information for freshwater quality monitoring. The experiments with NP-exposed D. magna showed that the pollutant has long-term effects on reproduction, whereas no short-term effect on DNA integrity was found, being an example of a false-negative result from the biomarkers perspective. This result could be interpreted that other mechanism than genetic alteration might be involved in NP-induced reproduction failure in D. magna. False-positive results from the genotoxic biomarker obtained in BPA-exposed D. magna and in NP-exposed C. tentans make it difficult to use DNA integrity as an early warning biomarker. However, as the mere presence of genotoxic compounds, which are potentially carcinogenic, is of high concern to human and ecosystem health, it could also be important to rapidly and effectively detect genotoxic compounds in the aquatic system in ways that do not necessarily accompany a higher level of alteration. Considering the potential of D. magna and C. tentans as bioindicator species, and the importance of genotoxic biomarkers in ecotoxicity monitoring, DNA damage in these species could provide useful information for environmental risk assessment.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.55-60
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• 2014

Background: Whether sentinel lymph node biopsy (SLNB) should be performed in patients with pure ductal carcinoma in situ (DCIS) of the breast has been a question of debate over the last decade. The aim of this study was to identify factors associated with microinvasive disease and determine the criteria for performing SLNB in patients with DCIS. Materials and Methods: 125 patients with DCIS who underwent surgery between January 2000 and December 2008 were reviewed to identify factors associated with DCIS and DCIS with microinvasion (DCISM). Results: 88 patients (70.4%) had pure DCIS and 37 (29.6%) had DCISM. Among 33 DCIS patients who underwent SLNB, one patient (3.3%) was found to have isolated tumor cells in her biopsy, whereas 1 of 14 (37.8%) patients with DCISM had micrometastasis (7.1%). Similarly, of 16 patients (18.2%) with pure DCIS and axillary lymph node dissection (ALND) without SLNB, none had lymph node metastasis. Furthermore, of 20 patients with DCISM and ALND, only one (5%) had metastasis. In multivariate analysis, the presence of comedo necrosis [relative risk (RR)=4.1, 95% confidence interval (CI)=1.6-10.6, P=0.004], and hormone receptor (ER or PR) negativity (RR=4.0, 95%CI=1.5-11, P=0.007), were found to be significantly associated with microinvasion. Conclusions: Our findings suggest patients presenting with a preoperative diagnosis of DCIS associated with comedo necrosis or hormone receptor negativity are more likely to have a microinvasive component in definitive pathology following surgery, and should be considered for SLNB procedure along with patients who will undergo mastectomy due to DCIS.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.44-55
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• 2008

Catalyzed by the recent development of space technology, various kinds of spacecrafts were launched and utilized with purposes in many developed countries. In case of emergency such as natural disasters, proper satellite images are required in order to help to mitigate and assess the effects of disasters on human life and property. Since there are limitations for a nation to single-handedly operate a satellite and fulfill complete demands, a development need of international cooperation organization to share satellite images among the member countries has risen. In this paper, preestablished four international organizations' background, objectives, and operating system, and their principal characteristics were analyzed and compared. Especially, the paper has focused on the analysis of on-going operating procedures and its cases for International Charter, UN SPIDER's development of local supporting network to support NFP, establishment of Web-GIS by Sentinel Asia under the goal of 'Digital Asia', and the utilization of GEO that is widely applied in natural disaster fields.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1341-1350
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• 2019

This research deals with algorithm for forest fire severity classification using multi-temporal KOMPSAT-3A image to mapping forest fire areas. The recent satellite of the KOMPSAT series, KOMPSAT-3A, demonstrates high resolution and multi-spectral imagery with infrared and high resolution electro-optical bands. However, there is a lack of research to classify forest fire severity using KOMPSAT-3A. Therefore, the purpose of this study is to analyze forest fire severity using KOMPSAT-3A images. In addition, this research used pre-fire and post-fire Sentinel-2 with differenced Normalized Burn Ratio (dNBR) to taking for burn severity distribution map. To test the effectiveness of the proposed procedure on April 4, 2019, Gangneung wildfires were considered as a case study. This research used the probability density function for the classification of forest fire damage severity based on R software, a free software environment of statistical computing and graphics. The burn severities were estimated by changing NDVI before and after forest fire. Furthermore, standard deviation of probability density function was used to calculate the size of each class interval. A total of five distribution of forest fire severity were effectively classified.

• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.627-635
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• 2020

With the increasing severity of climate change, intense torrential rains are occurring more frequently globally. Flooding due to torrential rain not only causes substantial damage directly, but also via secondary events such as landslides. Therefore, accurate and prompt flood detection is required. Because it is difficult to directly access flooded areas, previous studies have largely used satellite images. Traditionally, water indices such asthe normalized difference water index (NDWI) and modified normalized difference water index (MNDWI) which are based on different optical bands acquired by satellites, are used to detect floods. In addition, as flooding likelihood is greatly influenced by the weather, synthetic aperture radar (SAR) images have also been used, because these are less influenced by weather conditions. In this study, we compared flood areas calculated from SAR images and water indices derived from Landsat-8 images, where the images were acquired at similar times. The flooded area was calculated from Landsat-8 and Sentinel-1 images taken between the end of May and August 2019 at Lijiazhou Island, China, which is located in the Changjiang (Yangtze) River basin and experiences annual floods. As a result, the flooded area calculated using the MNDWI was approximately 21% larger on average than that calculated using the NDWI. In a comparison of flood areas calculated using water indices and SAR intensity images, the flood areas calculated using SAR images tended to be smaller, regardless of the order in which the images were acquired. Because the images were acquired by the two satellites on different dates, we could not directly compare the accuracy of the water-index and SAR data. Nevertheless, this study demonstrates that floods can be detected using both optical and SAR satellite data.

• Smart Structures and Systems
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• v.26 no.3
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• pp.277-290
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• 2020

Disasters, including earthquakes and landslides, have enormous economic and social losses besides their impact on environmental disruption. Iran, and particularly its Western part, is known as an earthquake susceptible area due to numerous strong ground motions. Studying ecological changes due to climate change can improve the public and expert sector's awareness and response to future disastrous events. Synthetic Aperture Radar (SAR) data and Interferometric Synthetic Aperture Radar (InSAR) technologies are appropriate tools for modeling and surface deformation modeling. This paper proposes an efficient approach to detect ground deformation changes using Sentinel-1A. The focal point of this research is to map the ground surface deformation modeling is presented using InSAR technology over Sarpol-e Zahab on 25^th November 2018 as a study case. For surface deformation modeling and detection of the ground movement due to earthquake SARPROZ in MATLAB programming language is used and discussed. Results show that there is a general ground movement due to the Sarpol-e Zahab earthquake between -7 millimeter to +18 millimeter in the study area. This research verified previous researches on the advanced image analysis techniques employed for mapping ground movement, where InSAR provides a reliable tool for assisting engineers and the decision-maker in choosing proper policies in a time of disasters. Based on the result, 574 out of 682 damaged buildings and infrastructures due to the 2017 Sarpol-e Zahab earthquake have moved from -2 to +17 mm due to the 2018 earthquake with a magnitude of 6.3 Richter. Results show that mountainous areas have suffered land subsidence, where urban areas had land uplift.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.152-152
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• 2019

This study demonstrates a novel approach of remotely sensed estimates of stream flow at fifteen hydrological station in the Han River Basin, Korea. Multi-temporal data of the European Space Agency's Sentinel-1 SAR satellite from 19 January, 2015 to 25 August, 2018 is used to develop and validate the flow estimation model for each station. The flow estimation model is based on a power law relationship established between the remotely sensed surface area of water at a selected reach of the stream and the observed discharge. The satellite images were pre-processed for thermal noise, radiometric, speckle and terrain correction. The difference in SAR image brightness caused by the differences in SAR satellite look angle and atmospheric condition are corrected using the histogram matching technique. Selective area filtering is applied to identify the extent of the selected stream reach where the change in water surface area is highly sensitive to the change in stream discharge. Following this, an iterative procedure called the Optimum Threshold Classification Algorithm (OTC) is applied to the multi-temporal selective areas to extract a series of water surface areas. It is observed that the extracted water surface area and the stream discharge are related by the power law equation. A strong correlation coefficient ranging from 0.68 to 0.98 (mean=0.89) was observed for thirteen hydrological stations, while at two stations the relationship was highly affected by the hydraulic structures such as dam. It is further identified that the availability of remotely sensed data for a range of discharge conditions and the geometric properties of the selected stream reach such as the stream width and side slope influence the accuracy of the flow estimation model.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.336-336
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• 2018

수문 모형에서 토지이용 자료는 수문해석에서 중요한 환경변수라고 할 수 있으며, 토지이용 자료의 정확도 및 해상도에 따라서도 수문해석 결과가 달라지기도 한다. 특히, SWAT 모형은 수문해석을 위한 알고리즘에서 고려하는 토지이용 관련 매개변수가 다양하며, 수문 모형의 적용성을 평가하는데 토지이용 관련 매개변수를 정확하게 추정하는 것이 중요한 요인이라 할 수 있다. 일반적으로 수문 모형의 검보정을 위해서는 각 년도에 맞는 토지이용자료를 이용하여야 하고, 각 년도별 매개변수를 달리하여 검보정을 실시하여야 하지만 토지이용 자료의 부족함과 수문모형 검보정의 편의성을 위해 특정년도의 토지이용 자료를 이용하여 고정된 매개변수를 이용하고 있다. 특히, 장래 수문변화를 고려하는 연구에서는 장래 토지이용 변화를 고려하여, 토지이용 변화에 따라 변화하는 매개변수를 고려하고 있으나 장래 수문해석에 있어 모든 매개변수를 토지이용 자료로만 추정할 수 없기 때문에 기 검보정에 사용한 매개변수를 일부 수용하여 적용하고 있는 실정이다. 그러므로 본 연구에서는 모형의 검보정에 있어 고정된 매개변수를 사용한 경우 (a)와 토지이용 변화에 따라 변화하는 토지이용 특성과 매개변수 간의 상호 관계를 이용한 경우 (b)를 비교하여 토지이용 변화에 따른 매개변수 변화를 고려한 경우의 수문 모형의 수문모형 해석 결과를 검토하였다. 본 연구에서는 연도별 토지이용 자료를 생산하기 위해서 무료로 공개하는 위성영상 중 자료의 공간해상도와 분광해상도가 상대적으로 좋은 Landsat 위성영상 자료와 Sentinel 위성영상을 고려하였다. 또한 연구대상지는 토지이용 변화를 뚜렷이 확인할 수 있고 유역 말단 부분에 수문 모니터링 (혹은 유량 자료가 구축된 곳)이 이루어지고 있는 지역으로 선정하였다.