• Title/Summary/Keyword: Bridge structure

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Entrepreneurial Financing: Program Review and Policy Perspective

  • Ham, Jin Joo
    • STI Policy Review
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    • v.5 no.1
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    • pp.75-97
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    • 2014
  • Entrepreneurial financing, such as publicly initiated venture capital or grant schemes, serves as an important policy instrument that aims to bridge the financing gap facing young, innovative businesses, a gap that is mainly due to higher risk and growing uncertainty, and to strategically promote the creation of new ventures through the revitalization of their venture capital industries. This study examines public venture capital initiatives in Australia, Canada, and Sweden, and discovered that all three countries actively foster their venture capital industry through the formation of funds or the provision of tax incentives. It is notable that the majority of financing initiatives heavily depend on supply-side measures rather than demand-driven policies that focus on stimulating private investment in technological innovations and discoveries. This paper discusses in-depth the policy impact of public financing initiatives and their subsequent side-effects raised in the process such as overlapping in funding structure across the country, lack of monitoring and evaluation for feedback, fragmentation across the government ministries and agencies, and competition with the private sector, which may cause inefficiency as a result of public intervention. Financial constraints may arise for many reasons, partly resulting from the lack of investment readiness of young entrepreneurs. This signals a policy shift towards the creation of market-driven demand away from the traditional supply-push approach, and is a grand challenge to policymakers in entrepreneurial financing. Attention is leaning towards the efficiency and effectiveness of these public-financing initiatives in terms of their policy roles. It is worth noting that policy should focus on generating synergy so available resources can be channeled into the early, risky stage of new ventures, working as facilitator to the achievement of an intended policy goal.

Deformation Characteristics of Construction Joint of Paved Track on Earthwork Section using the Accelerated Track Test (궤도가속실험을 통한 포장궤도 토공구간 시공이음매부의 변형특성 연구)

  • Lee, Il-Wha;Jang, Seung-Yup;Kang, Yoon-Suk;Um, Ju-Hwan;Kim, Eun
    • Journal of the Korean Society for Railway
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    • v.13 no.5
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    • pp.521-527
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    • 2010
  • The Paved Track is applied to reduce maintenance cost of conventional line. The Paved Track could be used in all types of lines including earthwork, bridge, tunnel and turnout sections. In case of earthwork section, the construction joint is the most critical factor to track durability. The construction joint does not affect to the track structure directly, but the gap due to discontinuity of slabs may affect to the long-term serviceability. To evaluate this problem, the accelerated track test has been performed on the construction joint and the middle part to of the real scale Paved Track. The purpose of this test is that evaluate the vulnerability of construction joint section comparing the trends of settlement and earth pressure under repeated loads of construction joint with those of the middle slab part.

Analytical Study of Shear Capacity for Large-Diameter Concrete-Filled Steel Tubes (CFT) (대구경 콘크리트 충전형 합성기둥의 전단성능에 관한 해석적 연구)

  • Jung, Eun Bi;Yeom, Hee Jin;Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.27 no.5
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    • pp.435-445
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    • 2015
  • Concrete filled steel tube(CFT), which has superior ductility and strength, is used for building column, bridge piers of ocean structure. Shear design equations of CFT existing in structural design provisions are excessively conservative. It has an effect on constructability and the economics of CFT. However, to suggest the reasonable shear design equation, experimental studies on the shear capacity of CFT have been rarely conducted. This study is analytical research to suggest improved shear design equations of large-diameter concrete-filled steel tubes. This analytical research was conducted to apply finite element analysis model of CFT based on the prior research. It was verified by comparison with prior test results. The verified model was used for parameter studies to estimate the influence of overhang length, concrete compressive strength and diameter-thickness ratio on shear strength.

Experimental Investigation of Large-Span Girder with Under-Tension System (언더텐션 시스템이 적용된 축소 실험체의 구조적 성능에 대한 연구)

  • Kim, Young-Min;Park, Dae-Ha;Lee, Ki-Hak;Lee, Jae-Hong
    • Journal of Korean Society of Steel Construction
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    • v.22 no.4
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    • pp.345-354
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    • 2010
  • This paper presents an experimental investigation of the structural performance of a large-span girder bridge with an under-tension system. Typical long-span structures with beam and girder members have greater structural member depths and sizes to carry the moment and deflection. An under-tension system can be an effective structural system, as it allows the cables to resist some portions of the vertical loadings and deflections. To evaluate the serviceability and ultimate strength of the under-tension system, two $10m{\times}2.4m$ experimental under-tension systems were built and tested. One was developed with an H-beam section, and the other was made with a PF500 section that had the advantages of fast construction and lower construction cost. In the test, the maximum deflections at the mid-point of both beams were effectively reduced using under-tension systems. Also, the increased tension forces in the cable reduced the deflections. The PF500 members, which had a new shape and were developed using the module systems, performed better than the typical H-beam sections in terms of the deflections and ultimate strength.

Local Deformation Analysis of the Orthotropic Steel Bridge Deck Due to Wheel Loadings Using FSM and FEM (윤하중에 의한 강바닥판 교면포장의 종방향균열 관련 수치해석법 개발)

  • Jeong, Jin Seok;Jung, Myung Rag;Ock, Chang Kwon;Lee, Won Tae;Kim, Moon Young
    • Journal of Korean Society of Steel Construction
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    • v.28 no.4
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    • pp.243-251
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    • 2016
  • Longitudinally structural cracks are sometimes observed in the pavement on steel plate deck bridges because traffic truck loadings can cause large local deformations of the thin deck plate stiffened by longitudinal and transverse beams. In this study, an improved finite strip method using flat-shell strip, prism, and link elements is presented to investigate local deformations of steel decks with pavements in which flexural and torsional stiffness effects of thin floor beams are rigorously taken into account. A simplified deck model extracted from steel plate-girder bridges is analyzed using the developed FSM and the commercial FE program, ABAQUS and also, their numerical results are compared and discussed.

Purification of Oxytocin-related Peptide, Isotocin from the Brain of Conger Eel Conger myriaster (붕장어(Conger myriaster)의 뇌로부터 Oxytocin-related Peptide, Isotocin의 정제)

  • GO Hye-Jin;KIM Chan-Hee;KIM Eun Jung;KIM In Hae;AN Sang Hyun;SOHN Hee-Young;PARK Jin-IL;PARK HEE Yun;YOON Ho Dong;PARK Nam Gyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.38 no.5
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    • pp.286-290
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    • 2005
  • Oxytocin (OT)-related peptide, isotocin was purified from the brain extract of conger eel (Conger myriaster) using reverse-phase, ion-exchange and size exclusion high performance liquid chromatography (HPLC). The sequence of the peptide, with a molecular weight of 967.30 Da, was determined as Cys-Tyr-Ile-Ser-Asn­Cys-Pro-Ile-Gly-$NH_2$, where the Cys between 1st and 6th residues made an intramolecular disulfide bridge by the automated amino acid sequence analysis and MALDI-TOF mass spectrometry. The sequence was confirmed by identical elution with the purified and synthetic peptide using the HPLC system. As a result of homology investigation, the primary structure of this peptide was the same as that of OT -superfamily member, isotocin. The synthetic peptide showed a contractile activity at a minimal effective concentration of $10^{-7}M$ on the intestinal smooth muscle of goldfish (Carassius auratus).

Monitoring of Pathogens and Characteristics of Fish Community in the Taewha River (태화강의 어류군집에 대한 병원체 모니터링)

  • Kim, Jin-Do;Yang, Hyun;Cho, Yong-Chul;Kim, Yi-Cheong;Cho, Mi-Young
    • Korean Journal of Environmental Biology
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    • v.28 no.3
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    • pp.143-149
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    • 2010
  • The pathogens and community structure of the fishes in Taehwa river were investigated from March 2007 to January 2009. During the study period, 3,504 individuals belonging to 35 species, 17 families and 9 orders were collected. The numerically dominant and subdominat species were Opsarichthys uncirostris (relative abundance 39.7%) and Hemibarbus labeo (relative abundance 30.9%). There were five Korean endemic species (20.8%) including Squalidus chankaensis tsuchigae, Zacco koreanus, Cobitis hankugensis, Coreoperca herzi, Odontobutis platycephala. The large fishes like Hemibarbus labeo or Opsarichthys uncirostris were gathered around the Samho bridge, sampling site 2 according to a season. The reaction to which two kinds of fish pathogenic virus is all negative and no fish pathogenic bacteria was isolated from 220 individuals. The fish pathogenic parasite not present variously with 7 species. Especially, Trichodina sp. was detected monthly and the infective density was high. But it is cosidered that temporary overcrowding of fish is not influenced mass mortality causing diseases in the specific site of river.

A Study of Seismic Resistant Design for Base-Isolated Bridges(I) (지진에 대비한 기초분리 교량의 설계법에 관한 연구(I))

  • Lee, Sang Soo
    • Journal of Korean Society of Steel Construction
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    • v.9 no.4 s.33
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    • pp.625-635
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    • 1997
  • The base isolation technique and its benefits in reducing the transmitted earthquake energy into a structure have gained increasing recognition during the last two decades. Unfortunately, the current available design procedures, especially for base-isolated bridges, seem inadequate and too restrictive. As a result, practical design procedure still relies upon a series of deterministic time history analyses. In this study, the evaluation of the possibility of the normal mode method to predict the nonlinear seismic responses of base isolated bridges has been performed. The applicability has been examined through the numerical approach with isolator's elastic or plastic states of the base isolated bridges. Numerical results show that the 1st. mode period and the various responses are varied with the state but are conversed. And, the result show that the normal mode method is applicable to predict the seismic responses and to design the babe isolated bridge. Various analysis method to bridges with bilinearized hysteresis isolator and various pier heights are evalulated.

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A Study of Seismic Resistant Design for Base-Isolated Bridges(II) (지진에 대비한 기초분리 교량의 설계법에 관한 연구(II))

  • Lee, Sang Soo;Yu, ChulSoo
    • Journal of Korean Society of Steel Construction
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    • v.9 no.4 s.33
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    • pp.637-647
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    • 1997
  • As stated in Part(I), the use of the isolator is meant to protect a structure from seismic risk, by concentrating the inelastic deformations to relatively cheap and replaceable devices while the rest of the structures remains elastic. This research has been carried out to investigate the effects of various structural parameters and isolator characteristics on the seismic response of Base Isolated Bridges. Simplified analysis method for practical design is developed by using the results. The Proposed Code-Type approach method can be used to estimate the inertial forces accurately, not only at the isolator but throughout the height of the Base-Isolated Bridges. The proposed method is recommended to use in preliminary design tool or even a final design tool for Base Isolated Bridges. For the validation of simplified design method, examples with artificial earthquake time history and design response spectrum for P.C Box Bridge with bilinear hysteretic steel damper are evaluated.

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Study on Elasto-Plastic Behavior of Column to Beam Connection with 600MPa High Performance Steel(SM 570 TMC) (기둥-보 용접접합부의 보단부 스캘럽형상과 탄소성 거동에 관한 실험적 연구 - 600MPa(SM570TMC)의 경우 -)

  • Kim, Jong Rak;Kim, Seung Bae;Kwon, June Yeop
    • Journal of Korean Society of Steel Construction
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    • v.20 no.6
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    • pp.691-700
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    • 2008
  • Contemporary architectural structures have diverse and complex forms. Such structural variety demands requisite performance from the connections in the steel structure so that the latter could resist a horizontal force, such as an earthquake. The connections are the all-important components that create the discontinuous form and that support stress concentration, determining the stiffness and toughness of the entire steel frame. In this study, a real-scale column-to-beam connection was constructed in the 600MPa-grade high-strength and high-performance steel, to test its behavior. Its material and welding characteristics were examined in this study, and its structural performance was analyzed by conducting seismic-resistance tests on the full-scale, cross-shaped column-to-beam welded connections with non-scallop, ordinary-scallop, and reinforced-scallop details. The weld ability of the high-strength, high-performance steel was also evaluated, and data regarding the seismic design for practical application were provided.