• Tuberculosis and Respiratory Diseases
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• v.52 no.4
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• pp.330-337
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• 2002

Background : A pulmonary tuberculoma is one of the most common causes of a solitary pulmonary lesion. Treating a tuberculoma is still controversial and there are few reports on antituberculosis chemotherapy. In this study, the clinical findings and changes in the size of tuberculomas on a radiograph after completing antituberculosis chemotherapy was investigated. Methods : The medical records, an chest radiographs of 18 pulmonary tuberculoma patients who were admitted to the Gachon medical school, Ghil medical center between April 1998 and August 2001, were reviewed. The symptomatic changes were recorded and the size of the tuberculomas following treatment were compared. To compare the size, the long distance of each tuberculoma on the chest radiographs were measured and the additional radiological findings of calcification, satellite nodules and cavities were investigated. Results : Fifteen patients were men and 3 were women. The median age was 46 (24-74). Among these 18 patients, 14 patients had clinical symptoms. The other 4 patients were diagnosed incidentally as during a routine chest radiograph. The mean size of the tuberculomas on the initial plain chest film was $4.3{\pm}2.3cm$(range : 1.7-10 cm) and after 6 months treatment, it had decreased to $1.68{\pm}2.00cm$(range : 1.5-6.5 cm) (P<0.05). At least 6 months of antituberculosis chemotherapy resulted in the findings of a tuberculoma with a disappearance in 9, a decreased size in 4, and no change in 5 on the chest radiograph. Calcifications were found in 3 patients on the initial chest film and the chest CT and all calcified tuberculomas had disappeared after treatment. Conclusion : Although a pulmonary tuberculoma can remain as an inactive lesion for a long time, if it is confirmed by pathological or bacteriological methods, antituberculosis chemotherapy will be beneficial despite the presence of calcification.

• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.625-629
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• 2011

In this study, we analyzed the signal environment of 17 DGNSS stations operated by DGPS Central Office through TEQC quality checking, visibility analysis and site visits. With TEQC, we produced times series of four indices of TEQC quality checking: observation ratio, L1 pseudorange multipath, L2 pseudorange multipath, and the frequency of cycle slip events. From visibility analysis, the directions where missing observations are happening were identified and the result was verified through onsite investigation. Without considering TEQC indices at the six sites(Palmido, Eochungdo, Geomundo, Pyeongchang, Seongju, and Chungju), the average TEQC indices were: 98% observation ratio, 0.19m of L1 pseudorange multipath, 0.71m of L2 pseudorange multipath, and 1.3 cycle slips per 1000 observations. The observation ratios at Palmido and Eochungdo were low. It was found that receiver settings were incorrect so that they could track the P2 signal of GPS satellites with L2C capability. No signal-blocking obstacles were found around the Geomundo station except the lighthouse. Thus, we guess that the poor TEQC indices at the site are believed to be caused by problems in the GPS hardware or cables. The low observation ratio at Pyeongchang is being caused by the surrounding hills blocking the satellite view from the south to the northwest directions. Even though all of four TEQC indices were bad at Seongju and Chungju stations, we found that the signal reception environment at the two sites is in good condition. We think that the quality indices got poor probably because of malfunctioning equipment. So, further investigation is needed for the Seongju and Chungju sites.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.441-450
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• 2005

The organic material is one of the most popular material for the satellites and the spacecrafts in order to perform the thermal management, and to protect direct exposure from the space environment. The present paper observes material property changes of organic material under the space environment by using ground facilities. One of the representative organic thermal management material of satellites, 2 mil ITO(Indium Tin Oxide) coated aluminized KAPTON was selected for experiments. In order to investigate the single parametric effect of protons in space environment, MC-50 cyclotron system in KIRAMS(Korea Institute of Radiological and Medical Science) was utilized for the ion beam irradiation of protons and ion beam dose was set to the Very Large August 1972 EVENT model, the highest protons occurrence near the earth orbit in history. The energy of ion beam is fixed to 30MeV(mesa electron volt), observed average energy, and the equivalent irradiance time conditions were set to 1-year, 3-year, 5-year and 10-year exposure in space. The procedure of analyses includes the measurement of the ultimate tensile strength for the assessment of quantitative degradation in material properties, and the imaging analyses of crystalline transformation and damages on the exposed surface by FE-SEM(Field Emission Scanning Electron Spectroscopy) etc.

• Journal of Life Science
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• v.31 no.9
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• pp.856-861
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• 2021

CD82/KAI1, identified as a metastasis suppressor, was initially known only as a molecular facilitator, but its various functions have recently been revealed. CD82 plays an important role in the stem-progenitor cell, angiogenesis, and muscle. We would like to introduce the recently reported functions and roles of CD82 in this review. CD82 is a member of the tetraspanin family, which consists of four transmembrane domains. The interaction between CD82 and cell adhesion molecules suppresses the metastasis of cancer. CD82 regulates the cell cycle of stem-progenitor cells in the stem cell niche. In the bone marrow, CD82 is expressed on long-term repopulating hematopoietic stem cells (LT-HSCs), which show multipotent differentiation potential. The interaction between CD82 and Duffy antigen receptor for chemokines (DARC) induces quiescence in LT-HSCs. CD82 also regulates Rac1 activity, resulting in the homing and engraftment of HSCs into the bone marrow niche. Besides, CD82 maintains the differentiation potential of muscle stem cells and prevents angiogenesis by inhibiting the expression of cytokines, such as IL-6 and VEGF and adhesion molecules in endothelial cells. CD82 is a key membrane protein that distinguishes the hierarchy of stem-progenitor cells, and is also important for amplification and verification of cellular resources. Further studies on the function of CD82 in various organs and cells are expected to advance cell biology and cell therapy.

• Journal of Korea Water Resources Association
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• v.56 no.3
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• pp.211-224
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• 2023

In this study, a soil moisture estimation was performed using the Water Cloud Model (WCM), a backscatter model that considers vegetation based on SAR (Synthetic Aperture Radar). Sentinel-1 SAR and Sentinel-2 MSI (Multi-Spectral Instrument) images of a 40 × 50 km² area including the Yongdam Dam watershed of the Geum River were collected for this study. As vegetation descriptor of WCM, Sentinel-1 based vegetation index RVI (Radar Vegetation Index), depolarization ratio (DR), and Sentinel-2 based NDVI (Normalized Difference Vegetation Index) were used, respectively. Forward modeling of WCM was performed by 3 groups, which were divided by the characteristics between backscattering coefficient and soil moisture. The clearer the linear relationship between soil moisture and the backscattering coefficient, the higher the simulation performance. To estimate the soil moisture, the simulated backscattering coefficient was inverted. The simulation performance was proportional to the forward modeling result. The WCM simulation error showed an increasing pattern from about -12dB based on the observed backscattering coefficient.

• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.388-396
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• 2007

This paper describes a multipath estimation method for Global Positioning System (GPS) dual frequency carrier phase measurements. Multipath is a major error source in high precision GPS applications, i.e., carrier phase measurements for precise positioning and attitude determinations. In order to estimate and remove multipath at carrier phase measurements, an array GPS antenna system has been used. The known geometry between the antennas is used to estimate multipath parameters. Dual frequency carrier phase measurements increase the redundancy of measurements, so it can reduce the number of antennas. The unscented Kalman filter (UKF) is recently applied to many areas to overcome some of the limitations of the extended Kalman filter (EKF) such as weakness to severe nonlinearity. This paper uses the UKF for estimating multipath parameters. A series of simulations were performed with GPS antenna arrays located on a straight line with one reflector. The geometry information of the antenna array reduces the number of estimated multipath parameters from four to three. Both the EKF and the UKF are used as estimation algorithms and the results of the EKF and the UKF are compared. When the initial parameters are far from true parameters, the UKF shows better performance than the EKF.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.366-374
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• 2009

ITU has considered the 3,400$\sim$4,200 MHz band, which is allocated worldwide on a primary basis to the FSS, as a candidate band for future development of IMT system. In this band, this paper presents the results of the sharing studies performed between FSS and IMT systems through the theoretical and simulation analysis on the interference from multiple IMT base stations into a receiving FSS earth station considering the interference mitigation techniques such as antenna tilt angle and 3 sectors on the IMT base station. By using the long-term and short-term interference threshold, the coordination areas for the FSS earth station are provided to share frequency in 3,400$\sim$4,200 MHz band between FSS earth station and multiple IMT base stations in future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.41-53
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• 2007

The Baekdudaegan Mountain Range is a backbone of the Korean Peninsula which carries special spiritual and sentimental signatures for Koreans as well as significant ecological values for diverse organisms. However, in spite of importance of this region, the forests of Baekdudaegan have been damaged in a variety of human activities by being used as highland vegetable grower, lumber region, grass land, and bare land, and are still undergoing destruction. The existing researches had determined the details of the damage through on-site and recent observations. Such methods cannot provide quantitative and integrated analysis therefore could not be utilized as objective data for the ecological conservation of Baekdudaegan forests. The goal of this study is to quantitatively analyze the forest damage in the Baekdudaegan preservation region through land cover categorization and change detection techniques by using satellite images, which are 1980s, and 1990s Landsat TM, and 2000s Landsat ETM+. The analysis was executed by detecting land cover changed areas from forest to others and analyzing changed areas' spatial patterns. Through the change detection analysis based on land cover classification, we found out that the deforested areas were approximately three times larger after the 1990s than from the 1980s to the 1990s. These areas were related to various topographical and spatial elements, altitude, slope, the distance form road, and water system, etc. This study has the significance as quantitative and integrated analysis about the Baekdudaegan preservation region since 1980s. These results could actually be utilized as basic data for forest conservation policies and the management of the Baekdudaegan preservation region.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.9 s.351
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• pp.31-37
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• 2006

Low-density parity-check (LDPC) codes are recently emerged due to its excellent performance. The standard for European high definition satellite digital video broadcast, DVB-S2 has adopted LDPC codes as a channel coding scheme. This paper proposes a DVB-S2 LDPC decoder architecture using a hybrid parity check matrix which is efficient in hardware implementation for both decoders and encoders. The hybrid H-matrices are constructed so that both the semi-random technique and the partly parallel structure can be applied to design encoders and decoders. Using the hybrid H-matrix scheme, the architecture of LDPC decoder for DVB-S2 can be very practical and efficient. In addition, we show a new Variable Node processor Unit (VNU) architecture to reuse the VNU for various code rates and optimized block memory placement to reuse. We design a DVB-S2 LDPC decoder of code rate 1/2 usng the proposed architecture. We estimate the performance of the DVB-S2 LDPC decoder and compare it with other decoders.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.167-177
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• 2015

This study was conducted to establish an inventory and propose conservation strategies for 'village wetlands' in Asan city, Korea, using GIS. As results, the village wetlands are defined as such places as 'palustrine' wetland, village embankment, agricultural reservoir or small reservoirs located in or near the village and related to everyday life or farming. Firstly 807 provisional village wetlands(draft) were identified in Asan by using Arc-GIS 10.1, then 196 wetlands(final) were defined finally as village wetlands and listed the inventory of Asan Village Wetlands after being validated through office works and field survey. The office works analyzed minimum area(greater than $625m^2$), satellite images, the Korea Land Information System, land use map and land coverage map. To evaluate the function and conservation values, the 37 wetlands were selected for detailed surveying and function assessment based on the following criteria : 1) doubled code both wetland and reservoir at digital map, 2) located less than 100m from village and 3) ecologically connected to such ecological resources as seaside mudflats, mountains and green area and ecological passages for small size wildlifes. As the result of the wetland function assessments by the RAM method, 7 wetlands were found to have 'high' wetland function (conservation) 18 wetlands were 'medium' (enhancement) and 12 wetlands were 'low' (restoration or enhancement). Enhancing biodiversity and ecosystem services through ecological management of wetlands in Asan and connecting with the Ecological Natural Degree were proposed.