• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.151-157
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• 2004

In this paper, we investigated ultra high speed wireless communication cell backbone net of city using of wireless communication transceiver for millimeter wave band. A new type of 60GHz wave band wireless transceiver using NRD waveguide. This 60㎓ transceiver has excellent signal's absorption characteristics of oxygen molecule than the other millimeter wave bands. We constructed to wireless networks interval within 500m to 3km on wireless backbone node using 60GHz transceivers, and did it so that city type wireless communication cell backbone networks of 155.52MbpsATM(OC-3) may be possible. Therefore, if use transceiver, it is possible that city type ultra high speed wireless communication cell backbone networks construction of 100Mbps, 155.52Mbps, 622Mbps, 1Gbps, and 1.2Gbps degrees.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.288-296
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• 2015

In many very high density cities in Asia in which there is limited area to expand, growth is forced upward as well as outward. Densely packed detached houses and low-rise buildings are replaced by lower density high-rises, leaving open spaces between high-rise buildings. Through this process, areas that formerly did not have much green space gain valuable green spaces, and new ecological corridors and patches are created. In this study, the demographic and housing-type changes of Wonju City were delineated using land use maps, aerial images, census data, and other administrative data. Green area changes were calculated using land cover data derived from multi-year Landsat TM satellite imagery. The values were then compared against demographic and housing-type changes for each administrative unit. The overall results showed a decrease of forested area in the city and an increase of developed area. Urban sprawl was clearly visible in many of the suburban areas. However, as expected, we also detected areas in which greenness did not decrease when the population greatly increased. These areas were characterized by residential building complexes of ten or more stories. If an equal number of housing units had been built as detached houses, these areas would not have kept as much green space. Our research result showed that high-density and high-rise residential structures can offer an alternative means to protect or create urban green spaces in high-density urban environments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.6-7
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• 2008

The purpose of this study was to investigate heat resistance for union type SMD inductor core. The samples was produced with process 5 step. In this study, it analysis heat resistance of SMD(Surface Mounted Device) inductor core and it get electric field only exist inside of SMD core. Therefore electric fields do not affect any device and equipments. These results are very important to design data acquisition system(several test equipments such as temperature, impedance, and current test), because data acquisition system can place under the SMD Inductor core. So, it can be decrease their test error due to electric field.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.493-499
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• 2003

Railroad, a superior mode of public transportation provides safe, efficient, speedy, comfortable and economical service, has fundamentally different characteristics from airplanes, ships and cars. Among the unique characteristics of a railroad is the fact that it operates on fixed track with multiple car trains. The subway system was first selected as the best solution to difficult automobile traffic conditions and environmental problems. Seoul subway no.1line (Jongno line) was opened for service on August 15, 1974. Seoul city has completed and now operates eight subway lines (286.7km) since 1974. At present the subways operate in Busan, Daegu and Incheon city, and are under construction in Gwangju and Daejeon city. The power source for subway trains has been electricity since 1896, and power supply systems are the third rail type and/or the catenary system. The typical catenary system is the rigid bar type. R-bar and T-bar are used in the rigid bar type of catenary system, and the two types of R-bar and T-bar are uesd in Korea also. R-bar is used only for AC 25kV power supply and T-bar for DC 1,500V. From 30 years of subway experience I would like to suggest the most economic catenary system to ensure of safety, reliability and expediency for the railway lines to be constructed and the forthcoming replacement due to the life cycle after studying and analysing the characteristics, advantages and disadvantages of R-bar and T-bar.

• Smart Structures and Systems
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• v.30 no.6
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• pp.583-599
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• 2022

In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.

• Journal of the Korean Regional Science Association
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• v.34 no.3
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• pp.55-68
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• 2018

This paper aims to analyze the changes of the population distribution of metropolitan area by the development of the new town-type innovative city, focusing on the case of the Daegu Innovative City. Using dataset in the survey of population trend and the migration statistics microdata provided by the Statistics Korea, we decomposed population changes of Daegu and surrounding regions into natural increase and social increases(net migration). As a result of the analysis, Dong-gu, where the Daegu Innovation City is located, experienced population growth due to its increase of net migration, whereas the total population in Daegu been decreasing continuously between 2007 and 2016. In particular, the occurrence of high net migration to Dong-gu in 2014 showed a pattern consistent with the completion of the Daegu Innovative City development and the relocation of government institutions from the Seoul metro area. As a result of analyzing the migration to Dong-gu, the population moved from the Seoul metro area was 6.9% of the total, while the population moving from the other 7 gu-gun areas in Daegu (35.8%) and the surrounding regions (8.2%) were significantly high. In particular, the migration to Dong-gu were from neighboring areas, such as Suseong-gu, Buk-gu and Gyeongsan-si. Therefore, the development of the new town-type innovative city could accelerate toward sprawling urban structure.

• Journal of Environmental Science International
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• v.23 no.9
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• pp.1619-1626
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• 2014

We analyzed diurnal variations in the surface air temperature using the high density urban climate observation network in Daegu metropolitan city, the representative basin-type city in Korea, in summer, 2013. We used a total of 28 air temperature observation points data(16 thermometers and 12 AWSs). From the distribution of monthly average air temperature, air temperature at the center of Daegu was higher than the suburbs. Also, the days of daily minimum air temperature more than or equal to $25^{\circ}C$ and daily maximum air temperature more than or equal to $35^{\circ}C$ at the schools near the center of Daegu was more than those at other schools. This tendency appeared more clearly on the days of daily minimum air temperature more than or equal to $25^{\circ}C$. Also, the air temperature near the center of the city was higher than that of the suburbs in the early morning. Thus it was indicated that the air temperature was hard to decrease as the bottom of the basin. From these results, the influence of urbanization to the formation of the daily minimum temperature in Daegu was indicated.

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.133-140
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• 2012

PURPOSES : Traffic situation of Seoul City is different each administrative district. because each administrative district population, average travel speed, etc are different. thus, regionally differentiated policy is necessary. METHODS : In this study, first, it is to implement the cluster analysis using the traffic factor of twenty-five administrative districts in Seoul, categorize it into the cluster and understand the properties. second, related factors of speed were derived. and method to increase the speed was investigated. we choose the eleven traffic factors such as the number of traffic accident cases, total length, speed, the number of cross section, the number of cross section per km, the rate of roads, registered cars, population attending office and school, population density, area. RESULTS : In the results, first, we could categorize the Seoul-City administrative district into three clusters. in order to find Factors associated with speed a simple regression analysis was performed. and the number of intersections per km is closely related to the speed. CONCLUSIONS : Through this study, transportation policies reflecting local traffic-related characteristics are required.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.3
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• pp.192-203
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• 2012

As a leading nation of ubiquitous technology, South Korea has been promoting u-City pilot projects throughout the country. According to 'Fundamental Construction Law of u-City,' u-City projects are classified into old-town and new-town types. However, most projects have focused only on the new-town type. Pushing forward large-scale land development projects, Korea Land and Housing Corporation (LH Co.) under Ministry of Land Transport and Maritime Affairs (MLTM) has gained a development profit out of the u-City infrastructure and then donated the infrastructure to a local government without making any plan for operations. In the process of u-City pilot projects, old-towns have been relatively ignored and various of unexpected problems have emerged. Building the u-City of an old-town is not easy due to many constraints such as huge initial investment, long validity and verification procedures, lack of useful services for citizens, lack of professional outsourcing methods for business promotion, high operating costs of the integrated control center, inadequate law related, insufficient institutional requirements and so on. This paper introduces a case study on u-City development for an old-town, Ansan City, as a private investment project. The case will help boost u-City projects for old-towns by solving their problems and providing an effective operational mechanism. As the first BTL (Build-Transfer-Lease) project for constructing u-City, 'Broadband Information Network Development Project' of Ansan City will provide a reference model of expanding u-City projects for other cities.

• Clinical Endoscopy
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• v.56 no.4
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• pp.510-520
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• 2023

Background/Aims: We aimed to investigate (1) promising clinical findings for the recognition of focal type autoimmune pancreatitis (FAIP) and (2) the impact of endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) on the diagnosis of FAIP. Methods: Twenty-three patients with FAIP were involved in this study, and 44 patients with resected pancreatic ductal adenocarcinoma (PDAC) were included in the control group. Results: (1) Multivariate analysis revealed that homogeneous delayed enhancement on contrast-enhanced computed tomography was a significant factor indicative of FAIP compared to PDAC (90% vs. 7%, p=0.015). (2) For 13 of 17 FAIP patients (76.5%) who underwent EUS-TA, EUS-TA aided the diagnostic confirmation of AIPs, and only one patient (5.9%) was found to have AIP after surgery. On the other hand, of the six patients who did not undergo EUS-TA, three (50.0%) underwent surgery for pancreatic lesions. Conclusions: Homogeneous delayed enhancement on contrast-enhanced computed tomography was the most useful clinical factor for discriminating FAIPs from PDACs. EUS-TA is mandatory for diagnostic confirmation of FAIP lesions and can contribute to a reduction in the rate of unnecessary surgery for patients with FAIP.