• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.115-120
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• 2014

To enhance the performance of an automobile turbocharger compressor, the circumferential inlet heights of the volute were modified and the flow field for the combined region of the diffuser and volute was numerically investigated using commercial software. Basically, a well-designed volute should have a high pressure recovery coefficient and a low loss coefficient for the total pressure. In this study, two circular volutes with the same cross sectional shape and tongue angle, but circumferentially different volute inlet heights, were selected. One volute had the middle inlet in the cross-section at the circumferential angle of $90^{\circ}$ but gradually lower inlet heights for the angles between $90^{\circ}$ to $360^{\circ}$ with respect to the cross sectional center of the volute, while maintaining the same height between the tangential line connecting the lowest positions of the cross section and the line connecting the volute inlets in the circumferential direction (case 1 volute). The other volute has an inlet height that is 2 mm lower than in case 1 volute such that the tongue section has a tangential inlet (case 2 volute). The results showed that the case 2 volute had a higher total pressure ratio because of its higher pressure recovery coefficient and higher isentropic efficiency, resulting from the lower loss coefficient along the circumferential position than the case 1 volute.

• Korean Security Journal
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• no.51
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• pp.293-313
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• 2017

The purpose of this study is to analyze the changes of regional clusters of national 16 areas on the assembly & demonstration in 2010 and 2015. The results of this study were as follows by using hierarchical cluster analysis. First, the regional clusters on the assembly & demonstration in 2010 were divided into three clusters in the first step: (1) Gwangju, Chungnam, Incheon, Chungbuk, Gyeongbuk, Daegu, Gangwon, Jeju, Daejeon, (2) Jeonnam, Gyeongnam, Busan, Jeonbuk, Ulsan, Gyeonggi, (3) Seoul. Second, the regional clusters on the assembly & demonstration in 2015 were divided into three clusters in the first step: (1) Ulsan, Gangwon, Chungbuk, Chungnam, Incheon, Gyeongbuk, Jeonnam, Gwangju, Jeju, Daegu, Daejeon, (2) Busan, Jeonbuk, Gyeongnam, (3) Seoul, Gyunggi. Third, The regional clusters on the assembly & demonstration were Busan, Jeonbuk, Gyeongnam of 'assembly & demonstration management area(labor related)', and Seoul, Gyeonggi of 'assembly & demonstration frequency areas' in 2015. This suggests that policing policies related to assembly & demonstration can be established and implemented flexibly in consideration of the degree of increase and decrease in assembly & demonstration by districts. Furthermore, it will be helpful to manage assembly & demonstration based on the 'police for human rights'.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.17-27
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• 2014

We investigated space-time patterns of Quaternary fault activity of the Yangsan fault zone using ESR ages in the Samnam-myeon region, Ulsan, Korea. Some of fault gouge zones consist of well-defined bands which added to the older gouge band, indicative of reactivation. During addition of new bands, the older gouge band was inactive, which represents the type I faulting mode. ESR analyses of each band of the gouge zone allow us to construct history of fault movement. The entire fault gouge zones were reactivated by type III faulting mode giving us ESR ages of the lastest reactivation. ESR dates show temporal clustering into active and inactive periods analogous to historic and paleoseismic fault activities. ESR ages and dates of fault movements indicate migration of fault activities along the Yangsan Fault Zone. Segments of the Quaternary faults in the study area are branched in the south of Sangcheon site. The earliest record of activity in segmented faults is recorded from the western segment to the northern segment. Before 750~850 ka ago, the fault gouge zone from the western segment to the northern segment were active. At 750~850 ka ago, the fault gouge zone from the eastern segment to the northern segment were active. During 630~660 ka and 480~540 ka only the northern segment was active. After 340 ka ago, the fault gouge zone from the western segment to the northern segment were active again.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.48-65
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• 2009

In order to understand the local vegetation history and the origin of rice cultivation, a phytoliths analysis was performed with sediments collected from archaeological site at Ga-dong in Gijang, Busan. From the analysis with the sediments of three sampling sites, fan-shape phytoliths of Oryza sativa were detected: sediment 8 ~ sediment 29 of sampling site 1, sediment 6 ~ sediment 20 of sampling site 2 and sediment 7 ~ sediment 33 of sampling site 3. On the bottom layers or near the bottom layers from the three sampling sites, high densities of Arundinoideae and Andropogoneae were detected. It indicates that these layers were wet soil environment when they were sedimented. From near bottoms up to surfaces, the densities of Arundinoideae and Andropogoneae were abruptly decreased, while the density of Oryza sativa was sharply increased. With these results, it should be considered that the rice cultivation was started from the Bronze Age on this region.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.16-22
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• 2024

Polymer electrolyte membrane fuel cells have the advantage of low operating temperatures and fast startup and response characteristics compared to others. Simulation studies are actively researched because their cost and time benefits. In this study, the resistance of water residual in the gas diffusion layer (GDL) of the unit cell was added to the existing equation to compare the actual data with the model data. The experiments were conducted with a 25 cm² unit cell, and the samples were separated into stopping times of 0, 10, and 60 minutes following primary impedance measurement, activation, and polarization curve data acquisition. This gives 0, 10, and 60 minutes for the residual water in the GDL to evaporate. Without the rest period, the magnitude of the performance improvement was not significantly different at the same potential and flow rate, but the rest period did improve the performance of the membrane electrode assembly when measuring impedance. By changing the magnitude of the resistance reduction to an overvoltage, the voltage difference between the fuel cell model with and without residual water was compared, and the error rate in the high current density region, which is dominated by concentration losses, was reduced.

• Health Policy and Management
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• v.24 no.1
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• pp.92-99
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• 2014

Background: Korea's primary care clinics are seeking increase in consultation fees by expanding supply within the frame of the health insurance system, but inequality of physician income between regions and individuals is exacerbating. The purpose of this study lies in analyzing the distribution of patients of primary care clinics, their specialized field, and the degree of inequality between medical fee income according to region. Data was acquired from the Health Insurance Review and Assessment Service on charged bills made by clinic-size medical institutions from 2008 to 2011. Methods: By comparing the outpatient number per clinic according to the clinic's specialized field, results showed that ophthalmology, otolaryngology, dermatology, orthopedics, and internal medicine showed high numbers whereas plastic surgery, neuropsychiatry, cardiothoracic surgery had fewer outpatients. The number of outpatients for clinic according to region showed Chuncheonnam-do, Jeju-do, Gangwon-do, Chungcheongbuk-do, Ulsan to have higher numbers of outpatients. For those four years, clinics in the Seoul area had a rather lower number. Results: As a result of comparing the decile hierarchy distribution ratio between specialized fields according to primary care clinics income from National Health Insurance, the inequality degree showed that obstetrics and gynecology and general medicine were each 0.130, 0.280 for the decile distribution ratio, which was the highest degree of inequality within the specialized field. Their Gini coefficient were also relatively high at 0.691, 0.528 respectively. On the other hand, the decile distribution ratio for otolaryngology and orthopedics were 0.510, 0.468, respectively, while their Gini coefficient each at 0.318, 0.314 makes their inequality degree relatively lower than other fields. Conclusion: This study is limited in that the data used was the health insurance charges submitted by clinics, which does not provide total information of the doctors' income. However, because most clinics are largely dependant on their income to come from health insurance reimbursements. Therefore, the results of this study can be used effectively. In the future, research that includes data on non-covered service income should be conducted to closely examine policy plans with a new medical fee policy which can resolve the medical fee income inequality issue between clinics as well as revitalize primary medical care.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.1
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• pp.1-17
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• 2020

The study aims to identify economic interdependencies between regions and define functional economic areas of Korea by analyzing inter-firm transaction networks. Previous research has relied on pre-given administrative boundaries or cultural homogeneity and used data such as commuting, population movement, and cargo flows which could not fully explain economic activities. To overcome the limitations, this study applies a community detection method to inter-firm transaction networks derived from the CRETOP+ database of Korean corporate data. The novel dataset and the network analysis enables us to identify Korea's functional economic areas based on actual inter-firm linkages. The result shows that there are six to seven economic blocs in the networks as of 2018. In particular, one huge economic bloc is formed integrating the Seoul metropolitan area, Chungcheong, and Gangwon provinces. Meanwhile, North Jeolla and South Jeolla provinces form two economic blocs separately rather than being tied up in one bloc due to the low frequency of transactions between each other. The two big economic blocs of Daegu-Gyeongbuk and Busan-Gyeongnam exist, and interestingly, Ulsan, Gyeongju, and Pohang form a separate middle-sized bloc across the administrative boundaries. The results reveal that the future balanced national development policies should be implemented based on functional economic areas derived from empirical data.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.439-444
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• 2011

This study is aimed to extract the key role of port operation organizations for the development of region ports and identify the operating efficiency priorities of three ports such as Busan, Incheon and UIsan port operated by PA(port authority). The Factor Analysis(FA) and Fuzzy Method were used as the analysis methodes. As an important role of port authority and regional maritime affairs & port office, thirteen sub-evaluation factors and four top-level evaluation factors were selected using the FA. Among the top-level evaluation factors i.e. 'port security, information management', service for regional society and customers', 'port marketing' and 'customer attraction', the most important factor was identified as 'port marketing'. The total port efficiency was evaluated using these factors and Fuzzy Method. As a result, Busan ranked 1st, followed by Incheon and Ulsan.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.437-444
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• 2017

The concentration of the HNS Accident for each region was confirmed to prepare against an HNS Spill accident by using a Concentration Index which is used to assess industry concentration trend. This is to present the HNS Accident Concentration Index by combining HNS Accident Scale Concentration Index and an HNS Accident Frequency Concentration Index based on the data of marine spill accidents including the HNS accident. Based on the HNS Accident Concentration Index, Ulsan was identified as a top priority region for preparedness, Yeosu, Busan and Taean were identified as priority regions for preparedness, Gunsan, Mokpo, Wando, Incheon, Tongyeong, Pyeongtaek and Pohang were identified as necessary regions for preparedness, Donghae, Boryeong, Buan, Seogwipo, Sokcho, Jeju and Changwon, in which no marine spill accidents occurred, were identified as support regions for preparedness.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.904-908
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• 2005

Recently the pathological actions of CagA of Helicobacter pylori (H. pylori) on gastric epithelial cells have been reported. CagA is directly injected into the host cytoplasm and undergoes tyrosine phosphorylation in the cells. In addition, translocated CagA forms a physical complex with SHP-2. There are two major CagA subtypes according to the amino acid sequence in the 3'region of CagA; i) the East Asian type (A-B-D of EPIYA motifs) and ii) the Western type (A-B-C of EPIYA motifs). Repeated EPIYA motifs in the 3'region of CagA are involved in the interaction with SHP-2. The East Asian type conferred stronger SHP-2 binding activity than the Westrrn type of CagA. Here we analyzed the amino acid sequences of the SHP-2 binding site of cagA gene in H. pyzori, and investigated whether there is my relationship between the diversities of cagA and the disease out-come in Korea. Most of Korean H. pylori strains showed A-B-D motifs(the East Asian type), and only one strain showed A-B-B-D motifs. In Korea, the incidence of atrophic gastritis and gastric cancer is significantly high compared with Western countries. The high frequency of the East Asian type CagA among Korean H. pylori strains would be involved in increasing the risk of gastric cancer in Korean populations.