• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.245-257
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• 2016

Although rivers cover only 0.5% of the total land area on the Earth, they are windows that show the integrated effects of watershed biogeochemistry. Studies on the loads and properties of riverine carbon have been conducted because they are directly linked with drinking water quality, and because regional or global net ecosystem production (NEP) can be overestimated, unless riverine carbon loads are subtracted. Globally, ${\sim}0.8-1.5Pg\;yr^{-1}$ and ${\sim}0.62-2.1Pg\;yr^{-1}$ of carbon are transported from terrestrial ecosystems to the ocean via rivers and from inland waters to the atmosphere, respectively. Concentrations, ${\delta}^{13}C$, and fluorescence spectra of riverine carbon have been investigated in South Korea to understand the spatiotemporal changes in the sources. Precipitation as well as land use/land cover can strongly influence the composition of riverine carbon, thus shifting the ratios among DIC, DOC, and POC, which could affect the concentrations, loads, and the degradability of adsorbed organic and inorganic toxic materials. A variety of analyses including $^{14}C$ and high resolution mass spectroscopy need to be employed to precisely define the sources and to quantify the degradability of riverine carbon. Long-term data on concentrations of major ions including alkalinity and daily discharge have been used to show direct evidence of ecosystem changes in the US. The current database managed by the Korean government could be improved further by integrating the data collected by individual researchers, and by adding the major components ions including DIC, DOC, and POC into the database.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.63-71
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• 2008

Recently according to supplying high resolution satellite imagery, we take much interest in the update and the revision of digital map and thematic map based on the satellite images. This study analyzed the modeling accuracy for QuickBird imagery and produced the digital map on a scale 1 to 5000 by way of showing an example. find an exhibition digital map was analyzed the positioning accuracy for the presentation of the possibility and the utility in the production and the revision to the digital map using QuickBird imagery. In order to analyze accuracies of constructed data, the digital topographic maps of 1:5000 scale which were produced by Korea National Geographic information Institute(NGI) were used. As a result, the RMSE was calculated at ${\pm}2.207$ m and 2.39 m in x and y direction respectively and it is within the permissible accuracy required for mapping on a scale of 1 to 5000 on the mapping rule notified by the National Geographic Information Institute. It is expected that the results of this study will be fully used in the field of large scale digital mapping and be utilized as basic information in applied field of the production and the revision of digital map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.505-513
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• 2010

This study investigate the characteristics of tidal constituents, and long-term mean sea level oscillations at Incheon bay. For this, the conditions of three tide stations around Incheon bay have examined, and carried out harmonic analysis on water level data for periods of about 40 years(1960~2007). Four major tidal constituents($M_2$, $S_2$, $K_1$, $O_1$) of each tide station showed tendency that change over the 18.61year lunar node cycle, and the type of tide at three stations is mainly semi-diurnal tides. And also, the past monthly tidal modulations are especially sensitive to the cumulative year of water level data in accuracy of tidal prediction. In case that regard the detached data at three tide stations as a single time series data of 40 years, the results of analysis on a single time series, long-term mean sea level oscillations and modulations of tidal datum at tide stations appears with a range of about 10cm, respectively. In addition, the predicted tides at the Inchcon harbor by global and regional tide models of OSU(Oregon State University) based on various satellite altimetric(Topex Poseidon, Topex Tandem, ERS, GFO) data are compared with the observed tides by KHOA(the Korea Hydrographic and Oceanographic Administration). The results show that the high resolution regional model is a quite good agreement at coastal shallow water region.

• Korean Journal of Head & Neck Oncology
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• v.24 no.1
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• pp.47-52
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• 2008

Purpose：The incidence of papillary thyroid microcarcinoma(PTMC) has increased due to the widespread use of high resolution ultrasonography and fine-needle aspiration biopsy. However, the clinical and biologic behaviors of PTMC is debatable. The aim of this study was to describe clinicopathologic features of PTMC and to suggest whether tumor size(5mm) might prove the useful parameter for determining the surgical strategy in PTMC. Material and Methods：From Jan. 2000 to Dec. 2005, 1355 of 2678 patients with papillary thyroid carcinoma were identified as having PTMC, based on tumor size${\leq}$10mm(50.6%). Among patients with PTMC, we further separated tumors<5mm(minute group：group M) from those 5 to 10mm(tiny group：group T). We compared the clinicopathological characteristics and the TNM stagings between two groups. Results：There were 114(8.4%) men and 1241(91.6%) women with a median age of 47 years(range；13-79). During a mean follow-up of 47.3(range；22-93), 13 patients(1.0%) developed locoregional recurrences and 3 patients(0.2%) showed distant metastases at initial presentation. Statistical analysis revealed that the presence of extracapsular invasion(p<0.0001), invasion to adjacent structure(p<0.0001), multifocality(p<0.0001), central lymph node metastasis(p<0.0001), and lateral lymph node metastasis(p<0.0001) were all significantly higher in tiny group(tumor${\geq}$5mm). Furthermore, minute group demonstrated a significantly lower tumor stage(AJCC TNM classification) compared with tiny group(p<0.0001). Conclusion：Patients with PTMC have a favorable treatment outcomes, although the distinction needs to be made with reference to the clinicopathologic behaviors. It would be reasonable to consider that tumor size(5mm) would be useful parameter for the treatment strategy of PTMC.

• Journal of Biomedical Engineering Research
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• v.27 no.5
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• pp.203-209
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• 2006

The aim of this study is to investigate the feasibility of ex vivo MR diffusion tensor imaging technique in order to observe the diffusion-contrast characteristics of human gastric tissues. On normal and pathologic gastric tissues, which have been fixed in a polycarbonate plastic tube filled with 10% formalin solution, laboratory made 3D diffusion tensor Turbo FLASH pulse sequence was used to obtain high resolution MR images with voxel size of $0.5{\times}0.5{\times}0.5mm^3\;using\;64{\times}32{\times}32mm^3$ field of view in conjunction with an acquisition matrix of $128{\times}64{\times}64$. Diffusion weighted- gradient pulses were employed with b values of 0 and $600s/mm^2$ in 6 orientations. The sequence was implemented on a clinical 3.0-T MRI scanner(Siemens, Erlangen, Germany) with a home-made quadrature-typed birdcage Tx/Rx rf coil for small specimen. Diffusion tensor values in each pixel were calculated using linear algebra and singular value decomposition(SVD) algorithm. Apparent diffusion coefficient(ADC) and fractional anisotropy(FA) map were also obtained from diffusion tensor data to compare pixel intensities between normal and abnormal gastric tissues. The processing software was developed by authors using Visual C++(Microsoft, WA, U.S.A.) and mathematical/statistical library of GNUwin32(Free Software Foundation). This study shows that 3D diffusion tensor Turbo FLASH sequence is useful to resolve fine micro-structures of gastric tissue and both ADC and FA values in normal gastric tissue are higher than those in abnormal tissue. Authors expect that this study also represents another possibility of gastric carcinoma detection by visualizing diffusion characteristics of proton spins in the gastric tissues.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.709-717
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• 2016

In this study, the convenience and efficiency of vision-based displacement measurement (VBDM) to estimate the cable tension of cable-stayed bridges and the requirements for its effective application were examined. To demonstrate its convenience and efficiency, it was confirmed that VBDM can be accomplished with a minimum amount of equipment using a commercial camcorder. In this case, it was found that the accuracy of estimation of the natural frequencies is sufficient, even though magnitude errors can occur when conducting high-speed recording at the low resolution afforded by the minimal equipment employed. It was also confirmed that the most important factor in detecting the precise natural frequencies is the use of the appropriate frequency range in the tension estimation using vibration. Based on these results, a study was carried out on the accuracy variation of the estimated tension according to the frame rate of a commercial camcorder. For this purpose, an experiment was performed to estimate the cable tension in a cable-stayed bridge model. Through this experiment, the detectable tensions of cables with various natural frequencies as a function of the frame rate were summarized. As a result, it was shown that the frame rate should be determined based on the natural frequency which is estimated to be located within the appropriate frequency range (approximately 10~75% of theoretical range) considering the aliasing and low-frequency distortion due to excitations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.292-301
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• 2016

Because damages arising from the occurrence of foot-and-mouth disease (FMD) are very great, it is essential to make a preemptive diagnosis to cope with it in order to minimize those damages. The main symptoms of foot-and-mouth disease are body temperature increase, loss of appetite, formation of blisters in the mouth, on hooves and breasts, etc. in a cow or a bull, among which the body temperature check is the easiest and quickest way to detect the disease. In this paper, an algorithm to detect FMD from the hooves of cattle was developed and implemented for preemptive coping with foot-and-mouth disease, and a hoof check test is conducted after the installation of a high-resolution camera module, a thermo-graphic camera, and a temperature/humidity module in the cattle shed. Through the algorithm and system developed in this study, it is possible to cope with an early-stage situation in which cattle are suspected as suffering from foot-and-mouth disease, creating an optimized growth environment for cattle. In particular, in this study, the system to cope with FMD does not use a portable thermo-graphic camera, but a fixed camera attached to the cattle shed. It does not need additional personnel, has a function to measure the temperature of cattle hooves automatically through an image algorithm, and includes an automated alarm for a smart phone. This system enables the prediction of a possible occurrence of foot-and-mouth disease on a real-time basis, and also enables initial-stage disinfection to be performed to cope with the disease without needing extra personnel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.685-693
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• 2017

This study aims to effectively respond to urban local rainstorms by classifying the risk against flood damage for each use district. The risk classification is based on sensitivity analysis of the socio-economic damage caused by local rainstorms in Changwon city, Korea by a Fuzzy model using data, such as the districts that provide institutional bases for land use, land prices, which estimate the property values, and floor area ratios, which measures the density and areas of flood damage. The analysis result indicated that flood damage in five districts of Changwon (Masan happo-gu, Masan Hoewon-gu, Sungsan-gu, Euichang-gu, and Jinhae-gu) is highest in the order of commercial areas, residential areas, industrial areas, and forests, which was attributed to high land price and floor area ratio of commercial areas. On the other hand, specific analysis in Masan Hoewon-gu and Sungsan-gu was different from the previous result, indicating that the risk against flood damage may vary according to the districts depending on their local conditions. The analysis from this study can be applied to future urban planning and be used as a guideline to estimate the potential flood damage. Overall, this study is meaningful in that it proposes an effective management of land use as a new resolution to mitigate of urban flood damage within a broader perspective of climate change and urbanization.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.362-373
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• 2015

This study analysed the effectiveness of aluminium(Al) filter in the added compound filtration for the removal of characteristic radiation from high atomic number material by DQE and image evaluation. 1mm Al was applied to each 0.1, 0.2, 0.3 mm copper and befere and after use were evaluated. Beam quality and DQE were tested by IEC regulations and image quality was evaluated by PSNR, MAE, MSE, CNR, SNR and qualitative analysis was performed by 7 items for resolution and contrast from chest x-ray criteria of national cancer checkup. MTF 10 and 50% were the same by 4.6, 2.54 cycle/mm and NPS, DQE, PSNR MAE, MSE, CNR, SNR and qualitative analysis were all the same or slightly better when Al was not used. PSNR is over 30dB and all significant and at the qualitative analysis, the p-value of t-test was over 0.05. The DQE and image quality evaluation have little difference between before and after use of Al filter and it is effective to use the Al filter for the reduction of skin dose by removal of characteristic radiation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.1-14
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• 2012

Traffic management centers (TMC) collect real-time traffic data from the field and have powerful databases for analysing, recording, and archiving the data. Recent advanced sensor and communication technologies have been widely applied to intelligent transportation systems (ITS). Regarding sensors, various in-vehicle sensors, in addition to global positioning system (GPS) receiver, are capable of providing high resolution data representing vehicle maneuverings. Regarding communication technologies, advanced wireless communication technologies including vehicle-to-vehicle (V2V) and vehicle-to-vehicle infrastructure (V2I), which are generally referred to as V2X, have been widely used for traffic information and operations (references). The V2X environment considers the transportation system as a network in which each element, such as the vehicles, infrastructure, and drivers, communicates and reacts systematically to acquire information without any time and/or place restrictions. This study is motivated by needs of exploiting aforementioned cutting-edge technologies for developing smarter transportation services. The proposed system has been implemented in the field and discussed in this study. The proposed system is expected to be used effectively to support the development of various traffic information control strategies for the purpose of enhancing traffic safety on highways.