• Spatial Information Research
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• v.21 no.2
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• pp.35-43
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• 2013

The aim of this research is to analyze the priority to functions of the U-city Service Aid Organization(USAO), which is to support invigorating U-City industry. This research analyzes the relative importance and the priority about the functional area and components of UASO based on AHP. This research also performs a sensitivity analysis. The research result shows that relative importance of functional area is like following orders: 1) distribution of U-City service-related information, 2) quality certification of U-City-related products and services, 3) R&D of U-City technology, 4) standardization of U-City, 5) U-City human resource development. The relative importance order of functional components is 1) establishment of U-City information distribution organization, 2) construction and management of U-City information distribution network, 3) supporting U-City information distribution and price policy, 4) providing U-City information list for distribution, 5) preparation and application of quality certification standard of U-City products and services, 6) research on legal system of U-City items, targets, and procedures for quality certification, 7) research, analysis, and provision of U-City information distribution situation, 8) level examination of constructed infrastructures and services in U-City, 9) U-City core technology development and localization of technology, 10) standardization of collected U-City information, service classification, distribution system. This research result can be applied directly to design functions of USAO. The result also can be used for duty management, human resource planning, or resource allocation.

• Progress in Medical Physics
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• v.18 no.3
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• pp.134-138
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• 2007

The current PET/CT system with high quality CT images not only increases diagnostic value by providing anatomic localization, but also shortens the acquisition time for attenuation correction than primary PET system. All commercially available PET/CT system uses the CT scan for attenuation correction instead of the transmission scan using radioactive source such as $^{137}Cs,\;^{68}Ge$. However the CT scan may substantially increase the patient dose. The purpose of this study was to evaluate quality of PET images reconstructed by CT attenuation map using various tube currents. in this study, images were acquired for 3D Hoffman brain phantom and cylindrical phantom using GE DSTe PET/CT system. The emission data were acquired for 10 min using phantoms after injecting 44.03 MBq of $^{18}F-FDG$. The CT images for attenuation map were acquired by changing tube current from 10 mA to 95 mA with fixed exposure time of 8 sec and fixed tube voltage of 140 kVp. The PET images were reconstructed using these CT attenuation maps. Image quality of CT images was evaluated by measuring SD (standard deviation) of cylindrical phantom which was filled with water and $^{18}F-FDG$ solution. The PET images were evaluated by measuring the activity ratio between gray matter and white matter in Hoffman phantom images. SDs of CT images decrease by increasing tube current. When PET images were reconstructed using CT attenuation maps with various tube currents, the activity ratios between gray matter and white matter of PET images were almost same. These results indicated that the quality of the PET images using low dose CT data were comparable to the PET images using general dose CT data. Therefore, the use of low dose CT is recommended than the use of general dose CT, when the diagnostic high quality CT is not required. Further studies may need to be performed for other system, since this study is limited to the GE DSTe system used in this study.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.284-284
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• 2016

Topological insulator (TI) is a bulk-insulating material with topologically protected Dirac surface states in the band gap. In particular, $Bi_2Se_3$ attracted great attention as a model three-dimensional TI due to its simple electronic structure of the surface states in a relatively large band gap (~0.3 eV). However, experimental efforts using $Bi_2Se_3$ have been difficult due to the abundance of structural defects, which frequently results in the bulk conduction being dominant over the surface conduction in transport due to the bulk doping effects of the defect sites. One promising approach in avoiding this problem is to reduce the structural defects by heteroepitaxially grow $Bi_2Se_3$ on a substrate with a compatible lattice structure, while also preventing surface degradation by encapsulating the pristine interface between $Bi_2Se_3$ and the substrate in a clean growth environment. A particularly promising choice of substrate for the heteroepitaxial growth is hexagonal boron nitride (h-BN), which has the same two-dimensional (2D) van der Waals (vdW) layered structure and hexagonal lattice symmetry as $Bi_2Se_3$. Moreover, since h-BN is a dielectric insulator with a large bandgap energy of 5.97 eV and chemically inert surfaces, it is well suited as a substrate for high mobility electronic transport studies of vdW material systems. Here we report the heteroepitaxial growth and characterization of high quality topological insulator $Bi_2Se_3$ thin films prepared on h-BN layers. Especially, we used molecular beam epitaxy to achieve high quality TI thin films with extremely low defect concentrations and an ideal interface between the films and substrates. To optimize the morphology and microstructural quality of the films, a two-step growth was performed on h-BN layers transferred on transmission electron microscopy (TEM) compatible substrates. The resulting $Bi_2Se_3$ thin films were highly crystalline with atomically smooth terraces over a large area, and the $Bi_2Se_3$ and h-BN exhibited a clear heteroepitaxial relationship with an atomically abrupt and clean interface, as examined by high-resolution TEM. Magnetotransport characterizations revealed that this interface supports a high quality topological surface state devoid of bulk contribution, as evidenced by Hall, Shubnikov-de Haas, and weak anti-localization measurements. We believe that the experimental scheme demonstrated in this talk can serve as a promising method for the preparation of high quality TI thin films as well as many other heterostructures based on 2D vdW layered materials.

• Journal of Gastric Cancer
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• v.20 no.3
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• pp.290-299
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• 2020

Purpose: Recently, totally laparoscopic gastrectomy has been gradually accepted by surgeons worldwide for gastric cancer treatment. Complete dissection of the lymph nodes and the establishment of the surgical margin are the most important considerations for curative gastric cancer surgery. Previous studies have demonstrated that indocyanine green (ICG)-traced laparoscopic gastrectomy significantly improves the completeness of lymph node dissection. However, it remains difficult to identify the tumor location intraoperatively for gastric cancers that are staged ≤T3. Here, we investigated the feasibility of ICG fluorescence for lymph node mapping and tumor localization during totally laparoscopic distal gastrectomy. Materials and Methods: Preoperative and perioperative data from consecutive patients with gastric cancer who underwent a totally laparoscopic distal gastrectomy were collected and analyzed. The patients were categorized into the ICG (n=61) or the non-ICG (n=75) group based on whether preoperative endoscopic mucosal ICG injection was performed. Results: The ICG group had a shorter operation time and less intraoperative blood loss. Moreover, significantly more lymph nodes were harvested in the ICG group than the non-ICG group. No pathologically positive margin was found and there was no significant difference in either the proximal or distal surgical margins between the 2 groups. Conclusions: Near-infrared fluorescence imaging with ICG can be successfully used in totally laparoscopic distal gastrectomy, and it contributes to both the completeness of D2 lymph node dissection and confirmation of the gastric transection line. Well-designed prospective randomized studies are needed in the future to fully validate our findings.

• KDI Journal of Economic Policy
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• v.14 no.3
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• pp.3-21
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• 1992

By localizing the production of core parts and intermediate goods previously imported from Japan, Korean firms have been striving to increase their market share and profit in the final goods market in which Japanese firms are dominating. Korean producers' efforts, however, have often been thwarted by Japanese suppliers' "strategic" behavior. This competitive strategy involves Japanese exporters supplying parts and intermediate goods at very high prices until Korean firms must locally develop them, and then setting the prices far below the previous level so that the profitability of localization is dramatically reduced, or even means a loss for the Korean manufacturer. This paper intends to explain the strategic behavior of Japanese firms through the concepts of strategic interactions and joint economies. Strategic interactions can be aggressive or accommodating depending on whether competitors are dealing with strategic substitutes or complements. Joint economies exist in multi-stage competition when competition in the previous state favorably influences "profits" of the ensuing stage. Competiton between Korean and Japanese firms (a two-stage game involving production and technology rivalries) can be characterized by joint economies and strategic substitutes: joint economies since technological improvement results in more profits in the production stage; and strategic substitutes since an increase in marginal profits of one firm brings about a decrease in marginal profits of the other in a duopolitic production stage. This implies that the flood of "low price" Japense substitutes is an almost "natural" phenomenon in the context of the duopolistic market described in this paper. In the technology competition stage, on the other hand, technology development and technology transfer can be either strategic complements or substitutes. This implies that, in typical comparative static analyses, the effect of changes in exogenous variables cannot be expected a priori. Thus it becomes very difficult to determine the desirability of applying various policy measures such as countervailing duties, R&D subsidies, and creating demand for localized products. For these reasons, it is indeed likely that the measures suggested as means of circumventing the strategic behavior of Japanese firms (and enhancing technological development of Korean firms) may not work.

• Journal of radiological science and technology
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• v.29 no.3
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• pp.125-132
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• 2006

The PET/CT scanner is an evolution in image technology. The two modalities are complementary with CT and PET images. The PET scan images are well known as low resolution anatomic landmak, but such problems may help with interpretation detailed anatomic framework such as that provided by CT scan. PET/CT offers some advantages-improved lesion localization and identification, more accurate tumor staging. etc. Conventional PET employs tranmission scan require around 4 min./bed position and 30 min. for whole body scan. But PET/CT scanner can reduced by 50% in whole body scan. Especially nowadays PET scanner LSO scintillator-based from BGO without septa and operate in 3-D acquisition mode with multidetectors CT. PET/CT scanner fusion problems solved through hardware rather than software. Such device provides with the capability to acquire accurately aligned anatomic and functional images from single scan. It is very important to effective detection from gamma ray source in PETdetector. And can be offer high quality diagnostic images. So we have study about detection processing of PET detector and high quality imaging process.

• Journal of Energy Engineering
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• v.29 no.1
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• pp.13-24
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• 2020

Many countries are actively engaging in the reduction of greenhouse gas emissions, and as part of this effort, gradually reducing the portion of coal power generation and instead increasing the portion of power generations from renewable energy sources and natural gas. Korea is taking a similar policy to expand LNG power generation for the next decade. There is a concern, though, about the policy not being aligned with the domestic industry development, since only a few products are being made in Korea along the LNG power generation industry value chain. Therefore in this paper, we first looked at the current status of the gas turbine and high temperature parts industry used for LNG power generation in Korea, and then looked into the industrial issues and challenges through the analysis of supply chains of the domestic gas turbine industry. Finally, we tried to propose strategies to revitalize and localize the domestic gas turbine and high temperature parts industry. The proposed strategies can be summarized as 1) creation of domestic gas turbine manufacturing ecosystem via construction of gas turbine alliance, 2) strategic R&D support for localization of gas turbine and high temperature parts, and 3) provision of domestic testbeds for technology evaluation and commercialization.

• Tuberculosis and Respiratory Diseases
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• v.69 no.2
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• pp.81-94
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• 2010

Background: Autophagy is an important adaptive mechanism in normal development and in response to changing environmental stimuli in cancer. Previous papers have reported that different types of cancer underwent autophagy to obtain amino acids as energy source of dying cells in nutrient-deprived conditions. However, whether or not autophagy in the process of lung cancer causes death or survival is controversial. Therefore in this study, we investigated whether nutrient deprivation induces autophagy in human H460 lung cancer cells. Methods: H460, lung cancer cells were incubated in RPMI 1640 medium, and the starved media, which are BME and RPMI media without serum, including 2-deoxyl-D-glucose according to time dependence. To evaluate the viability and find out the mechanism of cell death under nutrient-deprived conditions, the MTT assay and flow cytometry were done and analyzed the apoptotic and autophagic related proteins. It is also measured the development of acidic vascular organelles by acridine orange. Results: The nutrient-deprived cancer cell is relatively sensitive to cell death rather than normal nutrition. Massive cytoplasmic vacuolization was seen under nutrient-deprived conditions. Autophagic vacuoles were visible at approximately 12 h and as time ran out, vacuoles became larger and denser with the increasing number of vacuoles. In addition, the proportion of acridine orange stain-positive cells increased according to time dependence. Localization of GFP-LC3 in cytoplasm and expression of LC-3II and Beclin 1 were increased according to time dependence on nutrient-deprived cells. Conclusion: Nutrient deprivation induces cell death through autophagy in H460 lung cancer cells.

• Progress in Medical Physics
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• v.10 no.2
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• pp.63-71
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• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.2 no.1
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• pp.77-79
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• 2002

The urea cycle, consisting of a series of six enzymatic reactions, plays key roles to prevent the accumulation of toxic nitrogenous compound and synthesize arginine de novo. Five well characterized diseases have been described, resulting from an enzymatic defect in the biosynthesis of one of the normally expressed enzyme. This presentation will focus on two representative diseases; ornithine transcarbamylase(OTC) deficiency and citrullinemia(argininosuccinate synthetase deficiency). OTC deficiency is one of the most common inborn error of urea cycle, which is inherited in X-linked manner. We identified 17 different mutations in 20 unrelated Korean patients with OTC deficiency; L9X, R26P, R26X, T44I, R92X, G100R, R141Q, G195R, M205T, H214Y, D249G, R277W, F281S, 853 del C, R320X, V323M and 10 bp del at nt. 796-805. These mutations occur at well conserved nucleotide sequences across species or CpG hot spot. The L9X and R26X lead to the disruption of leader sequences, required for directing mitochondrial localization of the OTC precursor. Their phenotypes are severe, and neonatal onset. The G100R, R277W and V323M mutations were uniquely identified in patients with late onset OTC deficiency. The other genotypes are associated with neonatal onset. Out of 20 patients with OTC deficiency, only 6 patients are alive; two were liver transplanted, and normal in growth and development at 2, 4 years after transplantation respectively. Citrullinemia is an autosomal recessive disease, caused by the mutations in the argininosuccinate synthetase(ASS) gene. We identified in 3 major mutations in 11 unrelated Korean patients with citrullinemia; G324S, $IVS6^{-2}$ A to G, and 67 bp ins at nt 1125-1126. Among these, the 67 base pair insertion mutation is novel. The allele frequency of each mutation is; G324S(45%), IVS6-2 A to G(32%), and 67 base pair insertion(14%). All patients are diagnosed at neonatal or infantile age. Interestingly, two patients presented with stroke like episode. Out of 11 patients, 5 patients died. Among 6 patients alive, one patient was successfully liver transplanted.