• 복합신소재구조학회 논문집
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• 제1권1호
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• pp.27-33
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• 2010

Static analyses and buckling analyses were carried out for buried GFRP pipes by using finite element method. Vehicle loads, vertical and lateral soil pressures were considered as external loads, and supplying water pressure was considered as an internal load. Nine types of the factory-manufactured GFRP pipes were analyzed. Their maximum stresses and displacements were compared with the limit displacements and ultimate stress. Additionally, stress analysis on an enhanced flange, which was designed to reduce stress concentration, was performed. A cantilever analysis was carried out to know the maximum stress on the neck of the flange, which is the critical part. And a static analysis was carried for the buried flange. The test results showed that GFRP pipes were safe and stable against the external loads. And they showed that the enhanced flange decreased about 35% of the stress concentration.

• Geomechanics and Engineering
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• 제30권3호
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• pp.273-280
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• 2022

A certain amount of random vibration excitation to subway track is caused by subway operation. This excitation is transmitted through track foundation, tunnel, soil medium, and ground building to the ground and ground structure, causing vibration. The vibration affects ground building. In this study, the results of ANSYS numerical simulation was used to establish back-propagation (BP) neural network model. Moreover, a back-propagation neural network model consisting of five input neurons, one hidden layer, 11 hidden-layer neurons, and three output neurons was used to analyze and calculate the vertical Z-vibration level of New Capital's ground buildings of Qingdao Metro phase I Project (Line M3). The Z-vibration level under different working conditions was calculated from monolithic roadbed, steel-spring floating slab roadbed, and rubber-pad floating slab roadbed under the working condition of center point of 0-100 m. The steel-spring floating slab roadbed was used in the New Capital area to monitor the subway operation vibration in this area. Comparing the monitoring and prediction results, it was found that the prediction results have a good linear relationship with lower error. The research results have good reference and guiding significance for predicting vibration caused by subway operation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.755-770
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• 2006

1974. 8.15 SeoulMetro, beginning with the first electric railway established at six cities, so it is managing mass transportation of traffic. Especially, in case of seoul, It is managing that from one to eight lines, 286.9km, 265 stations have installed and now it is carrying about 5.5million of passengers everyday, and 2,000million passengers a year. So accident is increasing from the station every year. For this measure, SeoulMetro prepares safety fence for passengers crash but, as suicides or people who watch the accident took place, for at the bottom of passengers crash protection, PSD installing is needed. Even though, PSD is managing ATO section but, in controlling SeoulMetro, one to four lines sections are (ATS, ATC)section. Between as ATS, ATC section, ATO section, subway gate and PSD must have opened and crossed always at the time. And the interlock control corrosion protection gate, managing skills with installation, method, using in history, apply to 10rail cars one train sets, and maximum applying 224% sections of passengers congested that consideration is to be needed. So 2004, SeoulMetro improved technology and basic design of PSD at ATS section. Based on this, from 2005.4 to 2006.6, using subway 2lines per 12stations set the model installation(full type 11stations, half type 1station) After installing in case of success, it is going about to suggest that effective analysis and hereafter subject.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.751-752
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• 2010

• 한국철도학회논문집
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• 제15권1호
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• pp.80-87
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• 2012

본 연구에서는 인천 1호선 구간을 대상으로 2009년 집계된 스마트카드 데이터를 활용해 승객좌석점유(혼잡도)와 정시성 지표를 사용하여 도시철도 서비스를 평가하였다. 차량단위의 대중교통 서비스 평가를 위해 개별 이용객의 스마트카드 데이터를 스케줄에 의해 운행되는 차량단위로 집합화하였다. 분석결과 인천 1호선 하행선(계양${\rightarrow}$국제업무지구)의 오전 첨두 시간대(7시-9시)의 차내 혼잡과 차량의 정시도착 측면에서 낮은 서비스 수준을 보이는 것으로 분석되었다. 차내 혼잡도와 정시성 간에는 밀접한 연관성이 있으며 이는 이전 역에서의 높은 승객수요가 지속적인 열차의 연착을 발생시키는 것으로 분석되었다.

• ETRI Journal
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• 제27권4호
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• pp.355-366
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• 2005

Automatic discovery of physical topology plays a crucial role in enhancing the manageability of modern metro Ethernet networks. Despite the importance of the problem, earlier research and commercial network management tools have typically concentrated on either discovering logical topology, or proprietary solutions targeting specific product families. Recent works have demonstrated that network topology can be determined using the standard simple network management protocol (SNMP) management information base (MIB), but these algorithms depend on address forwarding table (AFT) entries and can find only spanning tree paths in an Ethernet mesh network. A previous work by Breibart et al. requires that AFT entries be complete; however, that can be a risky assumption in a realistic Ethernet mesh network. In this paper, we have proposed a new physical topology discovery algorithm which works without complete knowledge of AFT entries. Our algorithm can discover a complete physical topology including inactive interfaces eliminated by the spanning tree protocol in metro Ethernet networks. The effectiveness of the algorithm is demonstrated by implementation.

• ETRI Journal
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• 제34권6호
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• pp.800-806
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• 2012

Transmission performances of direct detection-based 100-Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal-to-noise ratio sensitivity, chromatic dispersion, cross-channel nonlinearity, and transmission distance on the performance of differential 8-ary phase-shift keying (D8PSK), differential phase-shift keying plus three-level amplitude-shift keying (DPSK+3ASK), and dual-carrier differential quaternary phase-shift keying (DC-DQPSK) are evaluated. The performance of coherent dual-polarization quadrature phase-shift keying (DP-QPSK) with block phase estimation and coherent DP-QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100-Gb/s signal over several hundred kilometers of a single-mode fiber link. The results also show that DC-DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC-DQPSK is comparable to that of coherent DP-QPSK with digital differential detection. The maximum transmission distance of DC-DQPSK is over 1,000 km, which is enough distance for metro applications.

• Structural Engineering and Mechanics
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• 제55권2호
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• pp.413-434
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• 2015

The vibrations caused by metro operation propagate through surrounding soil, further induce secondary vibrations of the nearby underground structures and adjacent buildings. In order to investigate the effects of vibrations caused by metro on use performance of buildings, vibration experiment of Chengdu museum was carried out firstly. Then, the coupling tunnel-soil-structure finite element model was established with software ANSYS detailedly, providing a useful tool for investigating the vibration performances of structures. Furthermore, the dynamic responses and vibration predictions of museum building were obtained respectively by the whole process time-domain analysis and frequency-domain analysis, which were compared with the vibration reference values of museum. Quantitative analyses of the museum building performance were carried out, and the possible tendency and changing laws of vibration level with floors were proposed. Finally, the related vibration isolation measures were compared and discussed. The tests and analysis results show that: The vertical vibration responses almost increased with the increasing of building floors, while weak floors existed for the curve of horizontal vibration; The vertical vibrations were larger than the horizontal vibrations, indicating the vibration performances of building caused by metro were characterized with vertical vibrations; The frequencies of the museum corresponding to the peak vibration levels were around 6~17Hz; The damping effect of structure with 33m-span cantilever on vertical vibration was obvious, however, the damping effect of structure with foundation vibration isolators was not obvious.

• 한국경제지리학회지
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• 제14권2호
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• pp.225-239
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• 2011

본 논문은 미국 조지아 주 애틀랜타와 인근 지역(이하 메트로 애틀란타)의 한인인구와 한인업체의 지역별 분포 및 특징을 살펴봄으로써 새롭게 부상하고 있는 메트로 애틀랜타 한인사회의 전반적인 성장과정을 파악하고자 한다. 특히 메트로 애틀랜타에 입지한 한인업체의 시기별 성장과정과 주요 지역 및 업종별 입지 동향 분석을 통해 한인업체의 공간적 분포의 특성을 파악하고자 한다. 이를 위해 애틀랜타 한인 이민의 역사를 살펴보았으며, 메트로 애틀랜타 한인업체의 입지 동향과 주요 업종별 입지 동향을 지역별로 분석하였다. 그 결과 메트로 애틀랜타 한인업체의 주요 입지는 교통의 발달, 새로운 지역의 개발, 교육 여건, 인종별 주거 비중의 변화 등으로 인해 애틀랜타 북동쪽의 외곽으로 급속히 확산되고 있음을 알 수 있었다. 이와 함께 한인업체의 주요 업종은 미국의 제도, 한인 거주민의 이주, 시장 전략 등에 따라 소매업과 음식점 및 주점업에서 부동산업과 금융업으로 전환되었고, 소매업의 입지 비중이 상대적으로 감소되었다는 사실도 밝혀졌다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.443-452
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• 2011

본 연구는 대중교통 카드 자료를 이용하여 대중교통 이용자의 통행행태를 분석한다. 통행행태 분석을 위해 토지 이용방식에 따라 공간적 범위를 주거지역, 업무지역, 쇼핑지역 등 세 종류로 분류하였다. 각 역별 환승 비율 분석 결과 주거지역이 쇼핑지구와 업무지구에 비해 환승 비율이 높게 분석되었으며 주거지역의 경우 마을버스 보다 지선버스 및 간선버스의 통행 비율이 더 높게 나타났다. 또한, 쇼핑지구와 업무지구의 간선 버스 및 기타 버스의 통행 비율이 마을버스 및 지선 버스 보다 더 높게 나타나 토지이용별로 버스 수단 이용에 있어 다소 차이가 있는 것으로 분석되었다. 보행거리는 일반적으로 사용 되어온 400m와 유사한 300m ~ 400m가 최대 보행거리로 분석 되었으며, 일반인보다 청소년의 최대 보행거리가 더 짧은 것으로 나타났다.