• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.404-420
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• 2021

In this paper, an automatic system of locating the indoor area with weak or no mobile signal was proposed and demonstrated experimentally by using the Internet of Things (IoT) technology. Nowadays, the technicians of mobile services providers need to go along with numerous heavy equipment to measure and record the mobile signal strength at outside environment. Recently, there are systems proposed to do such measurement at outdoor area by using the IoT technology automatically. However, these works could not be applied in the indoor area since there are difficulties to do the indoor mapping and positioning. In this work, the Bluetooth Low Energy (BLE) was used to tackle these two difficulties. After a proper placement of BLE in the testing site, while the technician walk around with a handheld analyzer, the data can be obtained accordingly for further analysis in the proposed system which includes the construction of floor plan, detection of mobile signal strength and suggestion of indoor base stations. The gift wrapping and centroid algorithms were used during the analysis. The experimental results showed that the proposed system successfully demonstrated the indoor mapping, positioning of weak mobile signal area and suggestion of indoor base stations for the normal rectangular rooms with an area of 100 m² on single floor.

• Journal of Advanced Marine Engineering and Technology
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• 제35권8호
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• pp.1132-1140
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• 2011

해상풍력발전단지 건설 시 기초지반이 해상 점성토층의 지반일 경우 플랜트 자체 하중의 영향과 풍력과 같은 외부 모멘트 영향으로 인해 침하 발생을 야기할 수 있기 때문에 연약지반 분포를 파악하는 것은 풍력플랜트 입지를 위해 매우 중요한 사항이다. 이러한 연약지반 분포를 파악하는 방법은 시추조사 방법이 가장 최적의 방법이지만, 현장의 여건이나 경제적 제약이 큰 단점을 가지고 있다. 따라서 이러한 문제점을 보완하기 위해 현재 지구통계학적 방법을 이용한 연구가 활발하게 진행되고 있다. 본 연구에서는 풍력 플랜트 설치를 가정한 해상 영역을 설정하여 지구통계학적 기법을 통하여 연약 지반층 두께 분포의 추정을 연구 수행하였다. 연약 지반층은 표준 관입시험치의 결과를 이용하여 구분하였으며, 지구통계학적 기법은 정규크리깅과 순차가우시안 시뮬레이션을 이용하여 결과를 비교하였다. 그 결과 비슷한 영역에서 최대 점성토의 두께를 가지는 영역이 나타남을 파악할 수 있었으며, 그 결과의 불확실성을 정량적으로 평가할 수 있었다.

• Korean Journal of Mathematics
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• 제22권2호
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• pp.235-252
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• 2014

In this paper, weak and strong convergence theorems of three step iteration process with errors are established for two weakly inward and non-self asymptotically nonexpansive mappings in Banach spaces. The results obtained in this paper extend and improve the several recent results in this area.

• 건축구조
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• 제14권4호
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• pp.79-86
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• 2007

Underground space development is more active on the latest date. Currently, we construct an connecting tunnel Euljiro underground shopping-area in seoul. we select DSM, considering geological condition and construction efficiency. The numerical analysis is performed with PENTAGON-3D and MIDAS CIVIL This paper will introduce the Earth Tunnel Method and make an examination possible to apply downtown weak ground.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.628-633
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• 2004

we studied the structural weak areas of an electric car bogie frame by finite element analysis. The bogie frame under consideration is a part of the standard electric car with aluminium car body. Vertical, torsional. lateral and longitudinal loadings were applied. Numerical results were compared with the experimental results. The two results are in a good agreement.

• 도시과학
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• 제7권2호
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• pp.1-9
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• 2018

In this study, Analysis of DRT model and contribustion based on the case of local governments adopting the Demand Responsive Transit(DRT) in order to provide transportation in public transportation service weak area. Based on the case of Yeoju Area, the contribution of the DRT was analyzed. The DRT model was established as a fixed and call type model with taxi and bus transportation. Based on the results of the happy taxi service in Yeoju Area in 2016, the contribution of DRT was analyzed. According to the happy taxi performance of Yeoju city, it was introduced to 27 villages, and operated 4,188 times. And 9,111 people used it and Yeoju Area supported about 53 million Won. The contribution of local governments was analyzed in terms of local government, users, and social aspects. On local government aspects, we analyzed the budget cuts and complaints resolution. On the user aspects, we analyzed waiting time reduction, walking time reduction, travel time reduction, comfort, punctuality, and stability. On social aspects, we analyzed taxi and regional economy activation, and convenience of mobility.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.107-108
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• 2022

In recent years, the construction industry has a tendency to increase of high-rise builidngs. High rise buildings can use limited space efficiently. But High rise buildings have problem that have extremely heavy weight. Various studies are being conducted to reduce the weight of buildings. Although lightweight aggregate is a meterial that can effectively reduce the weight of buildings, the strength of the aggregate itself is weak and the absorption rate is high, so the strength of the ITZ(Interfacial Transition Zone) area is weak. Therefore, it is essential to improve the interfacial area when using lightweight aggregates. In this study, an experiment was conducted to improve the adhesion between the aggregate and cement paste and to strengthen the interfacial area by coating the surface of the lighteight aggregate with Blast Furnace Slag. To confirm the improvement, compressive strength and EIS(Electrochemical Impedance Spectroscopy) measurements were perfromed. Using EIS, the change in electrical resistance of the cement hardened body was confirmed. As a result, it was confirmed that the lightweight aggregate coated on the surface showed highter compressive strength and electrical resistance than the non-coated lightweight aggregate, and that the coating material was filled in the interfacial area and inside the aggregate that helped to strengthen the compresssive strength and higher electrical resistance.

• 대한환경공학회지
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• 제33권6호
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• pp.439-446
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• 2011

본 연구에서는 도시 비점오염물질의 퇴적과 배출특성의 파악, 우수저류/침투 시설의 계획과 효율평가, 건전한 도시의 물환경관리 등의 관점에서, 고해상도 인공위성과 GIS를 병용한 도시내 상세 토지이용분류 방법을 제안하였다. 제안된 방법을 적용하여 도시유역을 네 종류의 지표면으로 분류하였으며, 기존의 실내조사방법이나 GIS만을 이용한 방법으로는 불투수면으로 파악되었던 전체 유역면적의 3%에 달하는 건물옥상이나 도로의 중앙분리대에 조성된 화단 등을 투수면으로 분류하였다. 강우유출모의의 정확도 향상에 있어서 토양피복별 분포 및 면적의 차이가 미치는 영향을 파악하기 위해, 추출된 각 토양피복에 강우손실 파라미터를 설정하여, 총강우량 7.1~15.0 mm의 강우사상에 대한 강우유출해석을 실시하였다. 기존의 10m 격자의 세밀토지이용 정보에 의한 토양피복 분류결과를 이용한 강우유출 해석에서는 관측유량과의 오차가 31~71%이었던 것이, 제안된 토양피복 분류기법을 이용한 강우유출 해석에서는 그 오차가 4~29%로 향상되었으며, 특히 강우규모가 적을 때의 유출수문곡선의 첨두유량과 유량증감부 등의 유출특성에 대한 재현성에 있어서 향상된 결과를 나타내었다.

• 한국디지털건축인테리어학회논문집
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• 제7권1호
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• pp.1-6
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• 2007

In this study, we fill a person's shoes human knowledge use a computer fast and simple repetition in architecture design. this study are launched from a assumption that a optimized arrangement spaces are able to measure and gauge. but automatic space arrangement program is first step, we have a value that propose a differential cell space and valuation space and process of optimized space arrangement. the merits of this design process are as follows; 1. this program has a advantage high the building-to-land ratio land and business area in space design. 2.this program can design a economy building and calculate rent benefit and calculate cost of construction. 3. this program can adapt for digital GIS. this program can down cost in labor productivity. 5. a layman can design high level. the weak point of this design process are as follows; 1. the design product is simple box shape. 2. this program has a weak in large area and complicated land shape 3. complex use space design are difficult in this program.

• 대한기계학회논문집B
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• 제24권1호
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• pp.132-142
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• 2000

The objective of this study is to experimentally investigate the noise propagating characteristics, the noise reduction mechanism and the performance of a slotted tube attached at the exit plane of a circular convergent nozzle. The experiment is performed through the systematic change of the jet pressure ratio and the slot length under the condition of two kinds of open area ratios, 25% and 51%. The open area ratio calculated by the tube length equivalent for the slot length is defined as the ratio of the total slot area to the surface area of a slotted tube. The experimental results for the near and far field sound, the visualization of jet structures and the static pressure distributions in the jet passing through a slotted tube are presented and explained in comparison with those for a simple tube. The propagating characteristics of supersonic jet noises from the slotted tube is closely connected with the slot length rather than the open area ratio, and its propagating pattern is similar to the simple tube. It is shown that the slotted tube has a good performance to suppress the shock-associated noise as well as the turbulent mixing noise in the range of a limited jet pressure and slot dimension. The considerable suppression of the shock‘associated noise is mainly due to the pressure relief caused by the high-speed jets passing through the slots on the tube. Both the strength of shock waves and the interval between them in a jet plume are decreased by the pressure relief. Moreover, the pressure relief is divided into the gradual and the sudden relief depending upon the open area ratio of the slotted tube. Consequently, the shock waves in a jet plume are also changed by the type of pressure relief. The gradual pressure relief caused by the slotted tube with the open area ratio 25% generates the weak oblique shock waves. On the contrary, the weak normal shock waves appear due to the sudden pressure relief caused by the slotted tube with the open area ratio 51%.