• Steel and Composite Structures
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• 제13권3호
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• pp.239-258
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• 2012

In this paper, experimental investigations on high strength steel (HSS) stud connected steel-concrete composite (SCC) girders to understand the effect of shear connector density on their flexural behaviour is presented. SCC girder specimens were designed for three different shear capacities (100%, 85%, and 70%), by varying the number of stud connectors in the shear span. Three SCC girder specimens were tested under monotonic/quasi-static loading, while three similar girder specimens were subjected to non-reversal cyclic loading under simply supported end conditions. Details of casting the specimens, experimental set-up, and method of testing, instrumentation for the measurement of deflection, interface-slip and strain are discussed. It is found that SCC girder specimen designed for full shear capacity exhibits interface slip for loads beyond 25% of the ultimate load capacity. Specimens with lesser degree of shear connection show lower values of load at initiation of slip. Very good ductility is exhibited by all the HSS stud connected SCC girder specimens. It is observed that the ultimate moment of resistance as well as ductility gets reduced for HSS stud connected SCC girder with reduction in stud shear connector density. Efficiency factor indicating the effectiveness of high strength stud connectors in resisting interface forces is estimated to be 0.8 from the analysis. Failure mode is primarily flexure with fracturing of stud connectors and characterised by flexural cracking and crushing of concrete at top in the pure bending region. Local buckling in the top flange of steel beam was also observed at the loads near to failure, which is influenced by spacing of studs and top flange thickness of rolled steel section. One of the recommendations is that the ultimate load capacity can be limited to 1.5 times the plastic moment capacity of the section such that the post peak load reduction is kept within limits. Load-deflection behaviour for monotonic tests compared well with the envelope of load-deflection curves for cyclic tests. It is concluded from the experimental investigations that use of HSS studs will reduce their numbers for given loading, which is advantageous in case of long spans. Buckling of top flange of rolled section is observed at failure stage. Provision of lips in the top flange is suggested to avoid this buckling. This is possible in case of longer spans, where normally built-up sections are used.

• 한국정보전자통신기술학회논문지
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• 제12권3호
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• pp.282-289
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• 2019

반사형 및 태양광 LED 도로 표지병은 도로 환경에 대한 시인성 확보 방법 중 하나로 사용되고 있다. 도로 표지병은 반사형 과 태양광 LED의 개별 제품으로는 범용성, 효율성, 간편성 및 시인성에 대한 장, 단점이 존재 하나 해당 부분 이외에 사고 후 2차 사고 방지 및 기타 교통 시스템과의 연계를 통한 확장성을 가지기 어렵다는 공통적인 단점을 가지고 있다. 본 논문은 기존 태양광 LED 도로 표지병에 RF 방식의 통신을 사용한 무선 제어 기능을 내장한 도로 표지병과 이를 제어하는 시스템에 대해 제안하였다. 제안된 시스템을 스마트 도로 표지병 시스템이라 하였으며 기존 태양광 LED 도로 표지병에 RF 방식의 통신 기능을 내장하여 중앙 통제실과 연계된 중앙제어장치 및 중계기를 통하여 해당 기기를 제어 할 수 있다. 또한 도로 상태에 따라 점등 방법, 색상 등의 제어가 가능하기 때문에 도로의 상태를 운전자에게 제공하여 사고 후 2차사고 방지에 대한 기능을 수행할 수 있다. 또한 LED 및 RF통신의 지속적인 전력 소모량을 최소화 하는 기능을 추가 하였다. 제안된 시스템의 유효성을 검증하기 위해 시작품을 제작 하였으며 기존의 시인성 확보를 통한 사고 방지 기능 외에 기타 교통 시스템과의 연계에 의한 사고 후 2차사고 방지 기능에 대학 역할이 가능함을 확인 하였다.

• 한국강구조학회 논문집
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• 제15권2호
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• pp.109-116
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• 2003

벽체용 박판냉간성형 Lip-C-형강의 구조적인 거동에 관한 연구의 일환으로 횡하중을 받는 스터드 벽체의 휨강도에 관한 실험적인 연구가 수행되었다. 시험체는 3개 또는 4개의 Lip-C-형강 스터드 부재의 양단을 C-형강 트랙으로 고정하여 제작되었다. 실험의 주요 변수는 스터드 복부의 천공 여부, 보강채널(bridge channel)의 간격 및 개수 그리고 보강 채널의 고정 및 스터드 플랜지의 간격 유지용 특수 클립(Clip)의 개수 등이며, 스터드의 인장측 플랜지에 부착된 합판과 석고보드의 벽에 강도에 미치는 영향이 연구되었다. 실험에 의한 휨강도는 AISI시방서(1996)에 근거한 강도와 비교하였다.

• Steel and Composite Structures
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• 제37권4호
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• pp.431-446
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• 2020

This paper presents the flexural performance of double skin composite beams (DSCBs) at different Arctic low temperatures. 12 DSCBs were prepared and tested under two-point loading at different Arctic low temperatures of 20, -30, -50, and -70℃. The studied parameters include low-temperature level (T), steel-faceplate thickness (t), shear span ratio (λ), and spacing of headed studs (S). The experimental investigations under two-point loading tests showed that flexural failure occurred to all DSCBs, even including the specimen designed with the small λ ratio of 2.9. The ultimate strength behaviours of DSCBs were improved due to the improved mechanical properties of constructional materials and the confinement on shear connectors. The DSCB subjected to two-point loading and low temperatures exhibits a five-stage working mechanism. The stiffness and strength indexes of DSCBs increase linearly with temperature and t value increasing, while decreasing as shear span ratio boosts. In the contrast, the change of S value from 150 to 200 mm has little effect on the ultimate strength behavior of DSCB.

• Steel and Composite Structures
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• 제18권4호
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• pp.1001-1021
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• 2015

Ultra-lightweight cement composite (ULCC) with a compressive strength of 60 MPa and density of $1,450kg/m^3$ has been developed and used in the steel-concrete-steel (SCS) sandwich structures. This paper investigates the structural performances of SCS sandwich composite beams with ULCC as filled material. Overlapped headed shear studs were used to provide shear and tensile bond between the face plate and the lightweight core. Three-dimensional nonlinear finite element (FE) model was developed for the ultimate strength analysis of such SCS sandwich composite beams. The accuracy of the FE analysis was established by comparing the predicted results with the quasi-static tests on the SCS sandwich beams. The FE model was also applied to the nonlinear analysis on curved SCS sandwich beam and shells and the SCS sandwich beams with J-hook connectors and different concrete core including ULCC, lightweight concrete (LWC) and normal weight concrete (NWC). Validations were also carried out to check the accuracy of the FE analysis on the SCS sandwich beams with J-hook connectors and curved SCS sandwich structure. Finally, recommended FE analysis procedures were given.

• Steel and Composite Structures
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• 제26권2호
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• pp.183-196
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• 2018

The traditional prestressed concrete composite box-girders with corrugated steel webs have several drawbacks such as large deflection and potential local buckling. In this study, two methods were investigated to optimize and improve the prestressed concrete composite box-girders with corrugated steel webs. The first method was to replace the concrete bottom slab with a steel plate and the second method was to support the concrete bottom slab on the steel flanges. The behavior of the prestressed concrete composite box-girders with corrugated steel webs with either method was studied by experiments on three specimens. The test results showed that behavior of the optimized and upgraded prestressed concrete composite box-girders with corrugated steel webs, including ultimate bearing capacity, flexural stiffness, and crack resistance, is greatly improved. In addition, the influence of different shear connectors, including perfobond leisten (PBL) and stud shear connectors, on the behavior of prestressed concrete composite box-girders with corrugated steel webs was studied. The results showed that PBL shear connectors can greatly improve the ultimate bearing capacity, flexural stiffness and crack resistance property of the prestressed concrete composite box-girders with corrugated steel webs. However, for the efficiency of prestressing introduced into the girder, the PBL shear connectors do not perform as well as the stud shear connectors.

• 복식
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• 제64권4호
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• pp.37-51
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• 2014

The purpose of this study is to devise a wide range of expression and direction in fashion by analyzing the wardrobe of David Bowie, a musician who represents Glam Rock, for "glam" characteristics. Research was done using dictionaries of musical terms, dictionaries of attire terms, internet, papers and books published in Korea and abroad and other materials. The results of this study showed four characteristics, and it can be summarized as follows. First, resistance refers to the deviation from the norms set by a mainstream society. The resistance in Glam Rock was expressed in depreciative and anti-social characteristics, and Punk elements were expressed by using studs and metallic materials. Second, androgyny in David Bowie's costume expresses the innate nature of gender by freely integrating or tight silhouette costumes. Third, the fantasy in Bowie's costumes is a concept as opposed to what is real and is expressed by using avant-garde and playful expressions. Distorted, exaggerated and avant- garde expressions express decorative and bizarre fantasy by using the images of an astronaut. Fourth, the folklore in David Bowie's costumes uses the patterns and images of different cultures, and is expressed as through integration of exotic components, including the usage of costumes with Oriental colors and shapes. Furthermore it represents geometric shapes and curves, using the images of Kimono.

• 한국수자원학회논문집
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• 제34권1호
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• pp.91-103
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• 2001

본 연구에서는 지표면유출과 하천유출의 실시간 연계를 통하여 하천 각 구간에서의 수위와 유량을 예측하는 수리학적 홍수추적 모형을 개발하였다. 주로 유역의 지형특성에 따라 결정되는 수문곡선의 형상을 반영하여 홍수 유출량 산정방법을 개선하였으며, 침투과정을 고려하여 강우초가 첨두유량의 과다산정을 제거하였다. 지표면유출의 하천유입을 연속방정식에 반영하여 여러 단면에서의 유입이 용이하였으며, 이는 강우의 급격한 변이에서도 수치적 안정을 가져다 주었다. 폭우시 양양 남대천 유역에서 현장 관측을 실시하였으며, 관측자료에 적용하여 개발된 모형의 현장 적용성과 신뢰성을 확보하였다.

• 한국통신학회논문지
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• 제24권10B호
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• pp.1876-1884
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• 1999

차세대 근거리 무선 통신망 및 무선 사설교환기 시스템들을 위해서 2.5GHz 대역의 주파수대역이 광범위하게 사용될 것이 기대된다. 이러한 시스템을 옥내에 설치하여 효율적으로 운용하기 위해서는 전파의 전파 특성의 이해가 중요하다 하겠다. 이 주파수대역의 파장의 길이가 건물의 크기에 비해 상당히 작으므로 광추적 기법을 이용한 전파 전파 예측방식이 많이 개발되고 있다. 그러나 광추적 기법의 정확도는 샐내외 벽에서 전파의 반사 및 투과 특성에 의존하는 바가 상당하다. 이에 본 논문에서는 현대 건축물에 흔히 많이 쓰이는 석고보드 벽과 시멘트 블록 벽의 전자파 특성을 이론적 및 실험적으로 분석하였다.

• 한국의류학회지
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• 제26권6호
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• pp.751-762
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• 2002

Korean apparel industry is facing critical moment due to shortage of labor, wage increases and intensive competition among domestic manufactures. In addition, international production has been shifting to China and the other low-wage countries from established locations such as Korea, Hong Kong and Taiwan. Global sourcing has been received considerable attention since firms can enhance their competitive advantage as well as comparative advantage by coordinating their sourcing activities global]y. This studs regarded global sourcing as one of the strategic tools to achieve competitive advantage of Korean apparel firms, and explored the current status by literature reviews and series of in-depth interviews with managers of korean apparel firms. The findings of this study were as follows: 1) Due to geographical advantage, China was the most favored nation for outsourcing for domestic markers. However, exporting firms preferred Latin America (including Mexico) to take advantage of duties, quotas and geographical proximity to the US market. 2) In selecting the global sourcing country, productivity, technical ability, local government regulation, and culture were considered important. 3) Most Korean apparel firms sources production globally, and followed by raw materials and trims. 4) Cost and quality were the most important factors in deciding subcontractors, and experience, productivity, equipment and finances were the next concerns. Academic implications and future directions were suggested based on findings.