• 대한기계학회논문집
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• 제17권2호
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• pp.331-341
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• 1993

The propagating crack problems under dynamic antiplane mode in orthotropic material is studied in this paper. To analyze the dynamic fracture problems by theoretical method or experimental method in orthotropic material, it is important to know the dynamic stress intensity factor in the vicinity of crack tip. Therefore the dynamic stress field and dynamic displacement field with dynamic stress intensity factor of orthotropic material in mode III were derived. When the crack propagation speed approachs to zero, the dynamic stress components and dynamic displacement components derived in this paper are identical to the those of static state. In addition, the relationships between dynamic stress intensity factor and dynamic energy release rate are determined by using the concept of crack closure energy with the dynamic stresses and dynamic displacements derived in this paper. Finally, the characteristics of crack propagation are studied with the properties of orthotropic material and crack speed. The variation of angle .alpha. between fiber direction and crack propagating direction and crack propagation speed fairly effect on stress component and displacement component in crack tip. The influence of crack propagation speed on the speed on the stress and displacement is greater in the case of .alpha.=90.deg. than in the case of .alpha.=0.deg. and the faster the crack propagation speed, the greater the stress value and displacement value.

• 기술혁신연구
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• 제16권1호
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• pp.239-259
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• 2008

Korea is in the middle of a transition from the catch-up stage to the post catch-up stage. This requires a new approach, a new perspective, and a new strategy to survive in the new environment. This research investigates the post catch-up research activities in the public sector, including universities and national research institutes. In this case study, the experts and research teams at the highest level in the world are introduced, and research environments and know-how possessed by the experts and research teams are analyzed. The cases shows that the post catch-up research teams have research patterns to open new research field and integrate prior knowledge base with new knowledges from other research field. They succeed in producing highly regarded research results and making research platform for further advanced research.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1283-1288
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• 2009

In general steel sheet piles are used in the containment system, which are vertical barrier systems for waste disposal and landfill purposes, and roads in excavation for temporary structure. This paper presents case study of the use of an interlocking sheet pile for water and containment. Cut-off Z-type sheet pile joints are investigated to determine their permeability from the field test. Four different joint sealing materials are used in field test. The results showed joint permeability is significant time-dependent and joint-dependent. These are explored and conclusions on permeability characteristics of different sealants are noted. A case study gives a design example as well as suggestion on permeability and water tightness can be implemented in using the sheet pile barrier in civil and environment works. From the test results, the effective sealing programs of sheet pile interlocks are suggested.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.27-30
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• 2009

This study is to evaluate the basic properties of concrete panels for surface finishing and to introduce the case of its application. As a result, the records of bending, abrasion resistance, impact strength were shown satisfied with KS standard. In a case of its application it was found production process can be simplified through a simplified manufacturing process. And also its cost-effective production and utilization practices are highly expected than imitation stone or native rock.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.392-401
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• 2006

In the July of 2006, devastating rainfalls ravaged the terrain in the province of Kangwon. These rainfalls resulted in debris flows, landslide and overflow over the habitat. Following these events, the urgent field study and countermeasures were to be needed and several methods were indicated. At each site, field observations were made and the properties of the channel and debris flow were broadly characterized. Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. The same goes for that case, debris flow has been reported frequently overseas and the extent of damages has been increased. But the hazards "debris flow" is still insufficiently researched and futhermore debris flows are very hard to predict. In this paper, the general overview of the debris flow problem and the mitigation method will be presented

• International Journal of Safety
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• 제9권2호
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• pp.16-21
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• 2010

In this study, the variations of transformed impact factors and load carrying capacity of highway bridges measured from the state of expansion joint are evaluated. the field loading tests were performed on the highway bridge with damaged expansion joint to investigate the variation of the load carrying capacity. From the field loading tests in case that damaged expansion joint exist or do not exist, the static displacements and dynamic displacements were measured, and TIF were calculated, respectively. dynamic test is performed in order to estimate dynamic displacement and TIF according to the level of damage of expansion joint. From the results of TIF, the load carrying capacity of highway bridges with damaged expansion joint were estimated.

• 한국콘텐츠학회논문지
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• 제19권2호
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• pp.36-48
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• 2019

이 연구의 목적은 4차 산업혁명의 기술적 토대가 되는 전자, 소프트웨어, 자동차 분야 융합교육에 대한 국내외 사례를 조사하고 산업체의 요구를 조사하는 것이다. 이를 위해 문헌연구를 통해 전자, 소프트웨어, 자동차중심의 융합교육분야를 도출하였고 전문가 검토를 통해 수정 보완하였다. 각 분야별 융합교육의 현황을 파악하기 위해 국내외 교육과정을 조사하였다. 그리고 융합교육분야에 대한 산업체의 요구를 조사하기 위해 해당 분야에 종사하는 직원 341명을 대상으로 수요조사를 실시하였다. 연구도구는 융합신기술 교육에 대한 필요성, 융합교육분야에 대한 수요, 학부 융합교육에 대한 요구 세 부분으로 구성하였다. 연구결과 전자분야보다 소프트웨어와 자동차분야에서 융합교육에 대한 요구가 높았으며 해당 분야 졸업생 고용의 지도 상대적으로 높은 것으로 나타났다. 융합교육의 운영형태에 대해서는 융합전공 또는 연계전공으로 운영되는 것이 바람직하다고 응답한 비율이 가장 높았다. 연구결과에 따라 융합교육 운영에 대한 시사점을 제안하였다.

• 대한예방한의학회지
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• 제20권3호
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• pp.93-113
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• 2016

Objectives : The focus of the review was laid on differences in research pertaining to thread embedding acupuncture between domestic and foreign journals. Methods : We collected 53 Korean articles on thread embedding acupuncture study from 4 Korean article searching sites, and 80 foreign articles from Pubmed. We analyzed the number of the theses according to the publication year, study method, journal, and subject. Results : A total number of 134 thread embedding acupuncture articles were categorized as 100 clinical trials, 14 experimental papers, and 19 literature reviews. Of the collected clinical trials, 55 were case studies, 6 were CCTs and 39 were RCTs. The domestic clinical trials were comprised of 36 case studies, 1 CCT, and 2 RCTs, and foreign clinical trials were comprised of 19 case studies, 5 CCTs, and 37 RCTs. Although only 12 of the 39 domestic clinical trials exclusively treated thread embedding acupuncture to the experimental group, 38 out of 61 foreign clinical trials undertook thread embedding acupuncture as the sole treatment. While the 2 domestic RCTs research had no significant evidence that the experimental group was different from the control group, the experimental group demonstrated better responses than the control group in 31 of the 37 foreign RCT studies. Conclusions : Studies on thread embedding acupuncture are more intensively studied in the foreign field in comparison to the domestic field. Referring to the results from the foreign thread embedding acupuncture studies, domestic use of thread embedding acupuncture should be expanded. Also, more refined research needs to be conducted in the domestic field in order for the Koran medicine to lead the thread embedding acupuncture. This study is limited in that the literature search in the foreign journals were restricted.

• 수산해양교육연구
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• 제24권2호
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• pp.180-202
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• 2012

The purpose of this study was to extract an u-PBL support system core value and design strategy based upon field experience learning. To accomplish this the study, first of all, analyzed the core values, design strategy which was selected after needs analysis and literature review of theories and cases regarding the PBL, e-PBL, blended-PBL, Field experience learning based on ubiquitous environment, and learning model based on ubiquitous technology. This study identified the three core values as; systemic support for instructional activity, just in time support for instructional activity and support for interaction facilitation. As further research areas, it might be useful to develop u-PBL instructional support system based upon the model designed from this study. Also, research concerning the verification of the model based upon implementation of the program case might be necessary.

• Earthquakes and Structures
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• 제17권6호
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• pp.533-543
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• 2019

This paper presents a study on the behavior of an RC bridge under near-field and far-field ground motions. For this purpose, a dynamic nonlinear finite element time history analysis has been conducted. The near-field and far-field records are chosen pairwise from the same events which are fits to the seismic design of the bridge. In order to perform an accurate seismic evaluation, the model has been analyzed under two vertical and horizontal components of ground motions. Parameters of relative displacement, residual displacement, and maximum plastic strain have been considered and compared in terms of near-field and far-field ground motions. In the following, in order to decrease the undesirable effects of near-field ground motions, a viscous damper is suggested and its effects have been studied. In this case, the results show that the near-field ground motions increase maximum relative and residual displacement respectively up to three and twice times. Significant seismic improvements were achieved by using viscous dampers on the bridge model. Somehow under the considered near-field ground motion, parameters of residual and relative displacement decrease dramatically even less than the model without damper under the far-field record of the same ground motion.