• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2008년도 제16차 학술대회
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• pp.178-178
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• 2008

In order to improve static stability and healing of reattached labrum, we combined the advantages of suture bridge and transosseous technique. Using the conventional 3 portal for anterior instability, check stability of bony Bankart and preparation of glenoid bed in 3 way including removal, reshaping or mobilization of bony fragment. Two anchors were inserted to the superior and inferior portion and medial edge of bony Bankart lesion. It usually corresponded to the area of IGHL. Medial mattress sutures were applied around IGHL complex to get enough depth of glenoid coverage using suture hook. Make 3.5mm pushlock anchor hole to the articular edge of glenoid cartilage. Proximal suture bridge was applied at first and then distal suture bridge was inserted to mobilize the labrum in proximal direction. These construction can provide more stable labral repair with wide contact and compression in case of deficient bony stability. It not only avoids technical disadvantage of point contact with anchor fixation, but also decreasing gap formation through cross compression of labrum that couldn't gain even with the transosseous fixation which affords linear compression effect. Additional bony stability could be gained if the the bony fragment was mobilized to the glenoid margin with potential healing bed or reshaped for the good contact with reattached labrum.

• 물과 미래
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• 제26권4호
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• pp.35-46
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• 1993

홍수시 교량에 의한 수위상승 효과를 해석하기 위하여 1차원 동역학적 방정식을 방정식으로 하고 교량부의 수위변동에 따른 흐름조건식을 내부경계조건으로 도입하였으며 이에 대한 Jacobian 메트릭스를 유도하여 해석하였다. 가상하도에 대한 모의실험결과 교량에 의한 수위상승에 영향을 미치는 주요인자는 교량에 의한 하도단면의 수축정도, 하도경사, 하도부의 조도계수, 유량계수등으로 나타났고 교량을 월류하는 경우에 유량계수의 영향은 비교적 작은 것으로 검토되었다. 본 연구에서의 해석기법을 태풍 그래디스(Gladys)로 인한 수영강 상류부의 홍수에 적용하여 그 활용성을 입증하였다. 계산결과치는 그 당시 조사된 홍수흔적치 등과 비교하여 합리적인 범위내에서 일치되었으며, 교량 상류부에서의 수위상승효과는 1.08~1.53m로 나타났다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 춘계학술대회 논문집
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• pp.85-93
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• 2005

평택항은 2001년 ‘평택항 종합개발 기간계획 정비용역’ 에서 선박의 내항 이용 방법이 갑문식에서 감조식으로 변경됨에 따라 기 건설된 서해대교 입구의 남측호안을 철거하여 선박이 상시 내항을 이용할 수 있도록 계획중이다. 이에 이 연구에서는 남측호안이 철거된 후 평택항을 고려하여 서해대교 하부를 통항하여 내항에 안전하게 입출항이 가능한지를 이론적 고찰 및 풀미션시뮬레이터를 이용하여 평가하고 문제점 발생시 대안을 제시한다.

• Structural Engineering and Mechanics
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• 제17권5호
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• pp.655-670
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• 2004

This paper aims to evaluate the effect of typhoons on fatigue damage accumulation in steel decks of long-span suspension bridges. The strain-time histories at critical locations of deck sections of long-span bridges during different typhoons passing the bridge area are investigated by using on-line strain data acquired from the structural health monitoring system installed on the bridge. The fatigue damage models based on Miner's Law and Continuum Damage Mechanics (CDM) are applied to calculate the increment of fatigue damage due to the action of a typhoon. Accumulated fatigue damage during the typhoon is also calculated and compared between Miner's Law and the CDM method. It is found that for the Tsing Ma Bridge case, the stress spectrum generated by a typhoon is significantly different than that generated by normal traffic and its histogram shapes can be described approximately as a Rayleigh distribution. The influence of typhoon loading on accumulative fatigue damage is more significant than that due to normal traffic loading. The increment of fatigue damage generated by hourly stress spectrum for the maximum typhoon loading may be much greater than those for normal traffic loading. It is, therefore, concluded that it is necessary to evaluate typhoon induced fatigue damage for the purpose of accurately evaluating accumulative fatigue damage for long-span bridges located within typhoon prone regions.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.505-524
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• 2010

Wireless structural monitoring systems consist of networks of wireless sensors installed to record the loading environment and corresponding response of large-scale civil structures. Wireless monitoring systems are desirable because they eliminate the need for costly and labor intensive installation of coaxial wiring in a structure. However, another advantageous characteristic of wireless sensors is their installation modularity. For example, wireless sensors can be easily and rapidly removed and reinstalled in new locations on a structure if the need arises. In this study, the reconfiguration of a rapid-to-deploy wireless structural monitoring system is proposed for monitoring short- and medium-span highway bridges. Narada wireless sensor nodes using power amplified radios are adopted to achieve long communication ranges. A network of twenty Narada wireless sensors is installed on the Yeondae Bridge (Korea) to measure the global response of the bridge to controlled truck loadings. To attain acceleration measurements in a large number of locations on the bridge, the wireless monitoring system is installed three times, with each installation concentrating sensors in one localized area of the bridge. Analysis of measurement data after installation of the three monitoring system configurations leads to reliable estimation of the bridge modal properties, including mode shapes.

• Smart Structures and Systems
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• 제23권4호
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• pp.359-371
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• 2019

As part of a structural health monitoring system, the relative geometric relationship between a ship and bridge has been recognized as important for bridge authorities and ship owners to avoid ship-bridge collision. This study proposes a novel computer vision method for the real-time geometric parameter identification of moving ships based on a single shot multibox detector (SSD) by using transfer learning techniques and monocular vision. The identification framework consists of ship detection (coarse scale) and geometric parameter calculation (fine scale) modules. For the ship detection, the SSD, which is a deep learning algorithm, was employed and fine-tuned by ship image samples downloaded from the Internet to obtain the rectangle regions of interest in the coarse scale. Subsequently, for the geometric parameter calculation, an accurate ship contour is created using morphological operations within the saturation channel in hue, saturation, and value color space. Furthermore, a local coordinate system was constructed using projective geometry transformation to calculate the geometric parameters of ships, such as width, length, height, localization, and velocity. The application of the proposed method to in situ video images, obtained from cameras set on the girder of the Wuhan Yangtze River Bridge above the shipping channel, confirmed the efficiency, accuracy, and effectiveness of the proposed method.

• Computers and Concrete
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• 제22권6호
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• pp.551-561
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• 2018

The percolation of interfacial transition zone (ITZ) in cementitious materials is of great importance to the transport properties and durability issues. This paper presents numerical simulation research on the ITZ percolation threshold of mortar specimens at meso-scale. To simulate the meso-scale model of mortar as realistically as possible, the aggregates are simplified as ellipsoids with arbitrary orientations. Major and minor aspect ratios are defined to represent the global shape characteristics of aggregates. Some algorithms such as the burning algorithm, Dijkstra's algorithm and Connected-Component Labeling (CCL) algorithm are adopted for identification of connected ITZ clusters and percolation detection. The effects of gradation and aspect ratios of aggregates on ITZ percolation threshold are quantitatively studied. The results show that (1) the ITZ percolation threshold is mainly affected by the specific surface area (SSA) of aggregates and shows a global decreasing tendency with an increasing SSA; (2) elongated ellipsoidal particles can effectively bridge isolated ITZ clusters and thus lower the ITZ percolation threshold; (3) as ITZ volume fraction increases, the bridging effect of elongated particles will be less significant, and has only a minor effect on ITZ percolation threshold; (4) it is the ITZ connectivity that is essentially responsible for ITZ percolation threshold, while other factors such as SSA and ITZ volume fraction are only the superficial reasons.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.95-100
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• 2022

In this paper, a power loss analysis technique of a high-frequency transformer of a bidirectional DAB (Dual Active Bridge) converter is reported. To miniaturize the transformer of the dual active bridge converter, a resonant inductor was designed with an air gap included low-coupled rate state core to combine leakage inductor with the resonant inductor which is required for soft-switching. In this paper, leakage inductance and magnetizing inductance, core material, type of winding and winding method are included in the dual active bridge transformer loss analysis process to enable optimal design at the initial design stage. Transformer loss analysis for dual active bridge with a switching frequency of 200 kHz and maximum output of 5 kW was executed, and elements necessary for design based on the number of turns on the primary side were graphed while maintaining the transformer turns ratio and window area. In particular, it was possible to determine the optimal number of turns and thickness of the transformer, and ultimately, the total loss of the transformer could be estimated.

• 한국구조물진단유지관리공학회 논문집
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• 제3권4호
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• pp.155-162
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• 1999

This paper presents a generation of analytical fragility curves for bridge. The analytical fragility curves are constructed on the basis of nonlinear dynamic analysis. Two-parameter lognormal distribution functions are used to represent the fragility curves with the parameters estimated by the maximum likelihood method. To demonstrate the development of analytical fragility curves, two of representative bridges with a precast prestressed continuous deck in the Memphis. Tennessee area are used.

• 미생물학회지
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• 제20권2호
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• pp.98-104
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• 1982

Detergent-degrading bacteria isolated from the Han River downstream running through the center of Seoul area were identified. Samples were monthly taken from the surface waters at four designated sites from October, 1980 to August, 1981. Isolated strains were characteristically Gram-negative bacteria in all, and they were classified within 18 genera, 43 spceies. The dominant strains of detergent -degrading bacteria were within geneus Pseudomonas. On the regional distribution of detergent-degrading bacteria, Euterobacteriaceae and genus Aeromonas were suddenly increased at the Third Bridge of site 2 and the First Bridge of site 3, and others were almost the same regardless of sites.