• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.883-896
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• 2023

As human activities in Korea are spread throughout the mountains, forest fires often affect residential areas, infrastructure, and other facilities. Hence, it is necessary to detect fire-damaged areas quickly to enable support and recovery. Remote sensing is the most efficient tool for this purpose. Fire damage detection experiments were conducted on the east coast of Korea. Because this area comprises a mixture of forest and artificial land cover, data with low resolution are not suitable. We used Sentinel-2 multispectral instrument (MSI) data, which provide adequate temporal and spatial resolution, and the k-nearest neighbor (kNN) algorithm in this study. Six bands of Sentinel-2 MSI and two indices of normalized difference vegetation index (NDVI) and normalized burn ratio (NBR) were used as features for kNN classification. The kNN classifier was trained using 2,000 randomly selected samples in the fire-damaged and undamaged areas. Outliers were removed and a forest type map was used to improve classification performance. Numerous experiments for various neighbors for kNN and feature combinations have been conducted using bi-temporal and uni-temporal approaches. The bi-temporal classification performed better than the uni-temporal classification. However, the uni-temporal classification was able to detect severely damaged areas.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.3-11
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• 2015

Purpose It is hard to obtain high quality images of knee and T.M joint because of a lot of soft tissues in the knee and T.M joint area. Most conventional system for high resolution scintigraphy was used by 4 mm aperture pinhole collimator. Performance comparison of high-resolution pinhole SPECT for Micro deluxe phantom using conventional system. the aim of this study is to evaluate performance of each aperture according to the diameter size and the usefulness of 24-hour delayed bone scintigraphy. Materials and Methods In this study 6 mm, 8 mm diameter pinhole collimators were mounted on Siemens E.CAM systems. In order to evaluate performance evaluation of each aperture and Micro Deluxe phantom was used for performance comparison of conventional SPECT system, Projection data were obtained with 9 degree increment per 30 second. Transverse images were reconstructed using dedicated OSEM algorithm with recovery of detector blurring. $^{99m}Tc-HDP$ source was used for 24-hour delayed bone scintigraphy. Results The knee joint images obtained with 24-hour delay were improved more than those obtained with 3-hour delay in our study. The 6 mm and 8 mm pinhole collimators FWHM have improved by 28% SNR and Uniformity have improved by 35%, Contrast has improved by 7% in 24-hour delayed knee joint image. While in 24-hour delayed T.M joint image of the 6 mm and 8 mm pinhole collimators FWHM have decreased by 60% SNR has decreased by 20% and Uniformity has decreased by 25%, Contrast has decreased significantly. Conclusion Pinhole collimators with 6 mm and 8 mm diameter could offer a superior performance for 24-hour delayed bone scintigraphy. The use of 24-hour delayed image provides additional benefits for pinhole scintigraphy of knee joint. Therefore, we expect that it is useful for precise diagnosis of knee joint and it is applicable to others joint imaging.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.101-114
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• 2023

In the wartime, aircraft carrying out a mission to strike the enemy deep in the depth are exposed to the risk of being shoot down. As a key combat force in mordern warfare, it takes a lot of time, effot and national budget to train military flight personnel who operate high-tech weapon systems. Therefore, this study studied the path problem of predicting the route of emergency escape from enemy territory to the target point to avoid obstacles, and through this, the possibility of safe recovery of emergency escape military flight personnel was increased. based problem, transforming the problem into a TSP, VRP, and Dijkstra algorithm, and approaching it with an optimization technique. However, if this problem is approached in a network problem, it is difficult to reflect the dynamic factors and uncertainties of the battlefield environment that military flight personnel in distress will face. So, MDP suitable for modeling dynamic environments was applied and studied. In addition, GIS was used to obtain topographic information data, and in the process of designing the reward structure of MDP, topographic information was reflected in more detail so that the model could be more realistic than previous studies. In this study, value iteration algorithms and deterministic methods were used to derive a path that allows the military flight personnel in distress to move to the shortest distance while making the most of the topographical advantages. In addition, it was intended to add the reality of the model by adding actual topographic information and obstacles that the military flight personnel in distress can meet in the process of escape and escape. Through this, it was possible to predict through which route the military flight personnel would escape and escape in the actual situation. The model presented in this study can be applied to various operational situations through redesign of the reward structure. In actual situations, decision support based on scientific techniques that reflect various factors in predicting the escape route of the military flight personnel in distress and conducting combat search and rescue operations will be possible.