• Title/Summary/Keyword: Real-Bridge

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A Study on the Static and Fatigue Behavior of Steel-Confined Prestressed Concrete Girder (강재로 구속된 프리스트레스트 콘크리트 합성거더의 정적 및 피로거동)

  • Kim, Jung Ho;Park, Kyung Hoon;Hwang, Yoon Koog;Lee, Sang Yoon
    • Journal of Korean Society of Steel Construction
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    • v.16 no.6 s.73
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    • pp.725-736
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    • 2004
  • A new type of girder, called steel-confined prestressed concrete girder (SCP girder), has been developed, which maximizes the structural advantages of concrete, steel, and PS tendon, and improves on the shortcomings of steel plate girder, PSC I-girder, and preflex girder bridge for use in the construction of middle- or long-span bridges. To verify the propriety of design, structural safety, and applicability of this girder, a static load test was carried out (Kim et al.., 2002). Since the main damage typically sustained by steel bridges results from the fatigue caused by the repetition of traffic loads, fatigue safety must therefore be guaranteed in applying the SCP girder in the construction of real bridges. In this study, a fatigue test was carried out to investigate fatigue behavior and provide basic data for fatigue design. Based on the fatigue test, the fatigue safety of the girder was estimated. For the fatigue test, 10-m specimens were designed for a standard-design truckload (DB-24). A static load test was also performed before the fatigue test to analyze the structural behavior of the specimens. After the fatigue test, outer steel plates were removed to observe the condition of the concrete in the girder.

Moving Object Tracking Using MHI and M-bin Histogram (MHI와 M-bin Histogram을 이용한 이동물체 추적)

  • Oh, Youn-Seok;Lee, Soon-Tak;Baek, Joong-Hwan
    • Journal of Advanced Navigation Technology
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    • v.9 no.1
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    • pp.48-55
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    • 2005
  • In this paper, we propose an efficient moving object tracking technique for multi-camera surveillance system. Color CCD cameras used in this system are network cameras with their own IP addresses. Input image is transmitted to the media server through wireless connection among server, bridge, and Access Point (AP). The tracking system sends the received images through the network to the tracking module, and it tracks moving objects in real-time using color matching method. We compose two sets of cameras, and when the object is out of field of view (FOV), we accomplish hand-over to be able to continue tracking the object. When hand-over is performed, we use MHI(Motion History Information) based on color information and M-bin histogram for an exact tracking. By utilizing MHI, we can calculate direction and velocity of the object, and those information helps to predict next location of the object. Therefore, we obtain a better result in speed and stability than using template matching based on only M-bin histogram, and we verified this result by an experiment.

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The Evaluation of Seismic Performance for Concrete-filled Steel Piers (콘크리트 충전 강교각의 내진 성능 평가)

  • 정지만;장승필;인성빈
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.5
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    • pp.53-58
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    • 2002
  • A recent development, a concrete-filled steel(CFS) pier is an alternative to a reinforced concrete bridge pier in an urban area, because of its fast construction and excellent ductility against earthquakes. The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

Prediction of Water-Quality Enhancement Effects of Gates Operation in the West-Nakdong River Using RMA2/RMA4 Models (RMA2/RMA4 모형을 이용한 서낙동간 수문연계운영의 수질개선 효과 예측)

  • Lee, Keum-Chan;Yoon, Young-Sam;Lee, Nam-Joo
    • Journal of Environmental Science International
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    • v.18 no.9
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    • pp.971-981
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    • 2009
  • An objective of this study is as follows: 1) performing sensitivity analysis and parameter estimation of RMA2 and RMA4 models for the West-Nakdong River, 2) drawing up alternatives of gates-operation for water-quality enhancement, and 3) quantitative evaluation of methodology of 'flow-restoration by gates-operation' among 'Comprehensive Plan Improving Water-Quality in the West-Nakdong River(WNR)' with the target water-quality(BOD at Nakbon-N point: below 4.3 mg/L). The parameters for the RMA2 (depth-averaged two-dimensional flow model) and RMA4 (depth-averaged two-dimensional water-quality model) were determined by sensitivity analysis. Result of parameter estimation for RMA2 and RMA4 models is $1,000\;Pa{\cdot}s$ of the eddy viscosity, 20 of the Peclet number, 0.025 of the Manning coefficient, and $1.0\;m^2/s$ of the diffusion coefficient. We have evaluated the effects of water-quality enhancement of the selected alternatives by numerical simulation technique with the models under the steady-state flow condition and the time-variant transport condition. Because of no-resuspension from river bottom and considering BOD as conservative matter, these simulation results slightly differ from real phenomena. In the case of $50\;m^3/s$ of Daejeo-gate inflow, two-dimensional flow pn results result represents that small velocity occurs in the Pyungkang Stream and no flow in the Maekdo River. In the WNR, there occurs the most rapid flow near timhae-bridge. In the WNR, changes of water-quality for the four selected simulation cases(6, 10, 30, $50\;m^3/s$ of the Daejeo-gate inflow) were predicted. Since the Daejeo-Gate and the Noksan-Gate can be opened up to 7 days, it would be found that sustainable inflow of $30\;m^3/s$ at the Daejeo-gate makes BOD in the WNR to be under the target of water-quality.

Object-Based Integral Imaging Depth Extraction Using Segmentation (영상 분할을 이용한 객체 기반 집적영상 깊이 추출)

  • Kang, Jin-Mo;Jung, Jae-Hyun;Lee, Byoung-Ho;Park, Jae-Hyeung
    • Korean Journal of Optics and Photonics
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    • v.20 no.2
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    • pp.94-101
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    • 2009
  • A novel method for the reconstruction of 3D shape and texture from elemental images has been proposed. Using this method, we can estimate a full 3D polygonal model of objects with seamless triangulation. But in the triangulation process, all the objects are stitched. This generates phantom surfaces that bridge depth discontinuities between different objects. To solve this problem we need to connect points only within a single object. We adopt a segmentation process to this end. The entire process of the proposed method is as follows. First, the central pixel of each elemental image is computed to extract spatial position of objects by correspondence analysis. Second, the object points of central pixels from neighboring elemental images are projected onto a specific elemental image. Then, the center sub-image is segmented and each object is labeled. We used the normalized cut algorithm for segmentation of the center sub-image. To enhance the speed of segmentation we applied the watershed algorithm before the normalized cut. Using the segmentation results, the subdivision process is applied to pixels only within the same objects. The refined grid is filtered with median and Gaussian filters to improve reconstruction quality. Finally, each vertex is connected and an object-based triangular mesh is formed. We conducted experiments using real objects and verified our proposed method.

Dynamic Behavior of the Prestressed Composite Girder by Modal Tests and Moving Train Analysis (프리스트레스트 강합성 거더의 모달테스트 및 이동 열차하중 해석에 의한 동적거동)

  • Kim, Sung Il;Lee, Pil Goo;Lee, Jung Whee;Yeo, In Ho
    • Journal of Korean Society of Steel Construction
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    • v.18 no.6
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    • pp.793-804
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    • 2006
  • Various PSC and steel-concrete composite railway bridges are being developed for short-medium spans with structural and economic efficiency. According to the design concept, the prestressed composite girder bridge has the advantages of being lightweight and having low girder depth, with the capacity for long spans. However, the dynamic behavior under a passing train is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate the modal parameters before performing dynamic analyses. In this paper, real-scale prestressed composite girders were fabricated as a test model and modal testing was carried out to evaluate modal parameters including natural frequency and modal damping ratio. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer was applied to obtain frequency-response functions, and the modal parameters were also evaluated after the fracture of test models. With application of reliable properties from modal tests, the estimation of dynamic performances of prestressed composite girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of a moving train.

Study on Fatigue Behavior and Rehabilitation of Stringer with Coped Section(I) -Experimental Study on Static and Fatigue Behavior- (절취부를 갖는 세로보의 피로거동과 보수·보강에 관한 연구(I) -정적거동 및 피로거동의 실험적 고찰-)

  • Hwang, Yoon Koog;Chang, Dong Il
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.363-375
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    • 1997
  • This study encompasses the performance of static and fatigue test for the 8 large scale test specimens to clarify the fatigue behavior of coped stringer and the effect of the repair and strengthening on the damaged stringer of the floor system in steel railway bridges. For the purpose of the research, the actual stress wave for the existing bridge was measured, the basic stress range frequency histogram was made and the equivalent stress range was calculated. Using the result from the equivalent stress range made by adjusting the stress range, the static and fatigue test was carried out by identifying the previous rehabilitation and after. As the result of the static tests, it was revealed that the level of local stress under the S1 specimen test of the real equivalent stress range was similar to tensile strength of the test material, and it was consistent with the requirement of the initiation condition of the fatigue crack. Through the various rehabilitation methods to the damaged specimens, the effects of the repair and reinforcement were analyzed. According to the results of the repair of effect, bolting the high tension bolt over the stop hole was confirmed to be more adequate method than drilling only stop hole to delay the fatigue crack growth. Futhermore, in case of the stringer subjected by bending moment, the reinforcement over the upper flange side was determined to be a useful strengthening method, and the reinforcement to the web of the stringer was not appropriate to accomodate as a adequate strengthening method. Also it was confirmed that the category of the fatigue design for the coped stringer met with the category E specified on the fatigue design criteria of the Highway Standard Specification in Korea.

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Fetishist Characteristics and Aesthetic Values of Glamour Style (글래머 스타일의 물신주의적 특성과 미적 가치)

  • Park, Ju-Hee;Kim, Min-Ja
    • Journal of the Korean Society of Costume
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    • v.57 no.4 s.113
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    • pp.173-187
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    • 2007
  • The purpose of this study is to analyze the fetishist characteristics and the aesthetic values of glamour style based on the premise that fetishism is the theoretical root of glamour style expressed in fashion throughout history. The following results are from analysing fetishist characteristics of glamour style. First, luxury was analysed from an angle of commodity fetishism. Every culture develops images and stories that portray a world in which its ideals are realized: a paradise, a utopia, a golden age, etc. Consumer goods often serve as 'bridges to these ideals'. People thus can fantasize about owning the perfect life. Crucially, however, they must never get everything they picture. That is why luxuries often take on displaced meaning. Glamour gives the displaced meaning visual form, making it beautiful and real. Second, the attention on the glamour of luxury goods as a bridge to ideals is connected to the glamour icon who is simultaneously a consumer of these luxury goods and a producer of cultural goods. Glamour icons including the courtesan of the late 19th century, the actress of the 1930s' Hollywood golden age and today's celebrities appear to efface the traces of production and create fetishist images in culture. Through this artificial principle, the commodity-cum-glamour icon comes to life as a splendid image of spectacle. Third, masquerade and seduction were analysed from an angle of sexual fetishism. A magnificent image of masquerade as sexual fetishism is often equated with femininity, especially in Hollywood movies, because the artificial seduction of the feminine -namely glamour- can be effected by the absence or silence of being. That is to say, the aesthetic revelation of femininity coincides with the fleshing out of artificial signs. Masquerade and the seduction of the feminine are connected with glamour's artificial sensuality from this point. Fourth, since 1980's when homosexuality as sexual deviation resurfaced as a hot topic, sexual ambiguity and bisexual image have gained attention as perverse sexuality. Next came queer theory, which reduced gender itself to a matter of surface rather than depth. According to queer theory, gender itself can be revealed as a kind of drag act. Drag's imitative performance may reveal that womanliness is just about 'dragging up'. Queerness as a decadent play makes a connection with the wicked origins of glamour. From these characteristics, four aesthetic values were deduced: ostentatious luxury and mysterious idolatry by commodity fetishism, artificial sensuality and playful queerness by sexual fetishism.

A Study on the Combination of the Existing Monitoring System with the Safety Management Network System (기구축 계측시스템의 안전관리 네트워크 시스템 연계 방안에 관한 연구)

  • Lee, Chin-Hyung;Park, Ki-Tae;You, Young-Jun;Joo, Bong-Chul;Hwang, Yoon-Koog;Bae, In-Hwan
    • Journal of Korean Society of societal Security
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    • v.2 no.3
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    • pp.47-53
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    • 2009
  • This study performed the construction of test bed for the combination of the health monitoring system In Yongjong grand bridge with the safety management network system in order to explore the feasibility of combining the existing monitoring system with the safety management network system. For this purpose, connection program which consists of DAQ sender server program and DAQ receiver server program has been developed. DAQ sender server program installed in the connection server, which is located on the DMZ zone of the existing monitoring system, plays the role of communicating with the monitoring system. On the other hand, DAQ receiver server program installed in the connection server, which is located on the integrated operation center of the safety management network system, plays the part of gathering real time and tim history data of the existing monitoring system and storing them in the integrated operation server through the communication with the DAQ sender. Test bed demonstrated the feasibility of combining the existing monitoring system with the safety management network system.

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Sensitivity Identification Method for New Words of Social Media based on Naive Bayes Classification (나이브 베이즈 기반 소셜 미디어 상의 신조어 감성 판별 기법)

  • Kim, Jeong In;Park, Sang Jin;Kim, Hyoung Ju;Choi, Jun Ho;Kim, Han Il;Kim, Pan Koo
    • Smart Media Journal
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    • v.9 no.1
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    • pp.51-59
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    • 2020
  • From PC communication to the development of the internet, a new term has been coined on the social media, and the social media culture has been formed due to the spread of smart phones, and the newly coined word is becoming a culture. With the advent of social networking sites and smart phones serving as a bridge, the number of data has increased in real time. The use of new words can have many advantages, including the use of short sentences to solve the problems of various letter-limited messengers and reduce data. However, new words do not have a dictionary meaning and there are limitations and degradation of algorithms such as data mining. Therefore, in this paper, the opinion of the document is confirmed by collecting data through web crawling and extracting new words contained within the text data and establishing an emotional classification. The progress of the experiment is divided into three categories. First, a word collected by collecting a new word on the social media is subjected to learned of affirmative and negative. Next, to derive and verify emotional values using standard documents, TF-IDF is used to score noun sensibilities to enter the emotional values of the data. As with the new words, the classified emotional values are applied to verify that the emotions are classified in standard language documents. Finally, a combination of the newly coined words and standard emotional values is used to perform a comparative analysis of the technology of the instrument.