• 한국전자통신학회논문지
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• 제12권6호
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• pp.1071-1080
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• 2017

최근 4차 산업혁명과 스마트 팩토리라는 용어를 뉴스나 매체를 통해 자주 들을 수 있다. 하지만 스마트 팩토리에 대한 정보와 어떻게 스마트 팩토리를 구축해야 하는지에 대한 구체적인 가이드라인이 없기 때문에 기업들로부터 외면 받고 있다. 스마트 팩토리의 구축은 도입 목적을 고려하여 회사의 규모에 적합하게 수행되어야한다. 기존 논문 연구에서 국내 대 중 소기업들을 대상으로 스마트 팩토리 성공구축 사례들을 분석 하였다. 사례분석 결과, 대기업의 경우 일부공장을 대상으로 시범적으로 스마트 팩토리를 구축한 후 성공적으로 평가될 시 전체공장으로 확대시키는 전략이 효과적이다. 중소기업의 경우, 낮은 수준의 스마트 팩토리 구축레벨에서 높은 수준의 구축레벨로 업그레이드하는 것이 효과적이다. 본 논문에서는 전통제조업체를 1개 선정하고, 3D가상공정설계를 통해 병목 구간과 개선이 필요한 공정을 파악한 후 센서를 설치한다. 최종적으로 센서를 통해 수집 된 데이터를 분석한 후 공정을 개선하고, 생산성이 향상된 스마트 팩토리를 구축하여 그 효과를 검증해 보고자 한다.

• Steel and Composite Structures
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• 제27권5호
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• pp.537-543
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• 2018

Mechanical shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface in composite beams. Steel pipe as a new shear connector is proposed in this research and its performance to achieve composite strength is investigated. Experimental monotonic push-out tests were carried out for this connector. Then, a nonlinear finite element model of the push-out specimens is developed and verified against test results. Further, the finite element model is used to investigate the effects of pipe thickness, length and diameter on the shear strength of the connectors. The ultimate strengths of these connectors are reported and their respective failure modes are discussed. This paper comprises of the push-out tests of ten specimens on this shear connector in both the vertical and horizontal positions in different reinforced concretes. The results of experimental tests are given as load-deformation plots. It is concluded that the use of these connectors is very effective and economical in the medium shear demand range of 150-350 KN. The dominant failure modes observed were either failure of concrete block (crushing and splitting) or shear failure of pipe connector. It is shown that the horizontal pipe is not as effective as vertical pipe shear connector and is not recommended for practical use. It is shown that pipe connectors are more effective in transferring shear forces than channel and stud connectors. Moreover, based on the parametric study, a formula is presented to predict the pipe shear connectors' capacity.

• Structural Engineering and Mechanics
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• 제65권6호
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• pp.771-784
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• 2018

This study aims to investigate the stochastic response of isolated and non-isolated highway bridges subjected to spatially varying earthquake ground motion model. This model includes wave passage, incoherence and site response effects. The wave passage effect is examined by using various wave velocities. The incoherency effect is investigated by considering the Harichandran and Vanmarcke coherency model. The site response effect is considered by selecting homogeneous firm, medium and soft soil types where the bridge supports are constructed. The ground motion is described by power spectral density function and applied to each support point. Triple concave friction pendulum (TCFP) bearing which is more effective than other seismic isolation systems is used for seismic isolation. To implement seismic isolation procedure, TCFP bearing devices are placed at each of the support points of the deck. In the analysis, the bridge selected is a five-span featuring cast-in-place concrete box girder superstructure supported on reinforced concrete columns. Foundation supported highway bridge is regarded as three regions and compared its different situation in the stochastic analysis. The stochastic analyses results show that spatially varying ground motion has important effects on the stochastic response of the isolated and non-isolated bridges as long span structures.

• 대한산업공학회지
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• 제37권4호
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• pp.304-310
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• 2011

The express courier business in Korea has been recognized as one of promising business sectors with the annual growth rate of over 10 percent since 2001. As such many domestic and foreign companies have been established and are fiercely competing to extend their own market share. The severe competition has forced them to focus on achieving cost competitiveness and high level of customer service. Small and medium-sized enterprises( SMEs) with relatively poor network infrastructure in particular are facing tougher challenges to cost reduction and efficiency improvement in their logistics networks. Strategic alliances among SMEs may be an effective way to cope with these challenges. Therefore this study proposes an integer programming model for compromised network design and its solution procedure based on maxmin and maxsum criteria for strategic alliances. The applicability and efficiency of the proposed model are demonstrated through an illustrative numerical example.

• Steel and Composite Structures
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• 제24권6호
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• pp.711-726
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• 2017

In the present work, by considering the agglomeration effect of single-walled carbon nanotubes, free vibration characteristics of functionally graded (FG) nanocomposite sandwich plates resting on Pasternak foundation are presented. The volume fractions of randomly oriented agglomerated single-walled carbon nanotubes (SWCNTs) are assumed to be graded in the thickness direction. To determine the effect of CNT agglomeration on the elastic properties of CNT-reinforced composites, a two-parameter micromechanical model of agglomeration is employed. In this research work, an equivalent continuum model based on the Eshelby-Mori-Tanaka approach is employed to estimate the effective constitutive law of the elastic isotropic medium (matrix) with oriented straight CNTs. The 2-D generalized differential quadrature method (GDQM) as an efficient and accurate numerical tool is used to discretize the equations of motion and to implement the various boundary conditions. The proposed rectangular plates have two opposite edges simply supported, while all possible combinations of free, simply supported and clamped boundary conditions are applied to the other two edges. The benefit of using the considered power-law distribution is to illustrate and present useful results arising from symmetric and asymmetric profiles. The effects of two-parameter elastic foundation modulus, geometrical and material parameters together with the boundary conditions on the frequency parameters of the laminated FG nanocomposite plates are investigated. It is shown that the natural frequencies of structure are seriously affected by the influence of CNTs agglomeration. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated plates.

• 대한안전경영과학회지
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• 제3권3호
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• pp.11-21
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• 2001

Domestic construction industry has considerable level of construction performance and technology thanks to the economic development and as the result of performing diverse oversea construction project. However, construction disasters have been steadily increasing, and do severe disasters at faster pace. Most of such disasters happen at small and small medium-sized construction fields, which contract size is less than 10 billion won. small and medium-sized construction fields are not obliged to designate a safety manager, and have limitations in engaging self-regulating disaster prevention activities due to reduced budget for safety facilities. For the small and medium-sized construction sites with less than 10 billion won, the Ministry of Labor has been carrying out mobile inspections of construction safety. However, the effect so far is insignificant and an improvement plan is required. Therefore, in the present thesis, we derive problems appearing in the current construction safety mobile inspection system, investigate and study systems in foreign countries, and suggest an efficient and effective plan to operate safety technology inspections. First of all, we establish a standard to select sites to be inspected that are high in construction risk and disaster occurrence probability In addition, we suggest a plan to take administrative and judiciary measures based on the total score for disaster factors considering the disaster occurrence probability and the illegal practices. Furthermore, a scheme to maximize the effect of disaster prevention is sought by building an organic cooperative system between the Ministry of Labor, Korea Occupational Safety ＆ Health Agency and other organizations specialized in instruction of construction disaster prevention. Finally, we induce a research conclusion that leads to self-regulating safety management through checking and instructing systematic management on mobile inspections.

• Imaging Science in Dentistry
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• 제45권1호
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• pp.31-39
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• 2015

Purpose: This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. Materials and Methods: CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. Results: The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. Conclusion: Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.

• 한국지반환경공학회 논문집
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• 제13권5호
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• pp.13-24
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• 2012

국토의 효율적 이용과 기간시설 수용을 위한 대단위 부지 확충 및 대규모 항만배후부지 개발이 계획 중에 있으며, 이에 따라 해안지역의 준설매립은 지속적으로 이루어지고 있다. 슬러리 상태의 초연약 상태인 준설매립 지반은 오랜 시간에 걸쳐 침강 및 자중압밀 과정을 거치게 되며 투기한 준설토를 압밀 촉진시켜 침하시킬 수 있다면 기존 처분지의 수명을 연장시킬 수 있으므로 경제적으로 유용하리라 판단된다. 재하중 없이 공기를 단축시키고 매립 물량을 증대시키기 위하여 small column test와 medium column을 보완, 개발한 medium column test를 실시하여 PBD와 침투압이 동시에 작용하였을 PBD의 효과 및 침투압의 침강 및 자중압밀 촉진 효과를 검토하였다. 연구 결과, 기존의 자중압밀 공법에 비하여 침투압과 PBD를 적용한 지반은 배수재의 배수거리 단축에 따른 투수 상승 효과와 침투압에 의한 침투 압밀의 효과가 활발히 이루어지는 것으로 나타났다. 이를 통해 매립 직후나 매립 도중에 연직드레인을 직접 타설하여 침강 및 자중압밀 과정을 단축시키면 전체 매립공사 공기를 단축시킬 수 있으며 압밀촉진에 따라 확보된 여유고 만큼 준설토 투기가 가능해져 투기 준설토량을 경제적으로 증대시킬 수 있을 것으로 기대된다.

• 기술혁신연구
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• 제24권3호
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• pp.53-79
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• 2016

기술이 발달하고 기업환경이 급변하면서 중소기업의 기술혁신활동에 있어 지식서비스를 효과적으로 활용하는 것에 대한 사회적 요구가 급증하고 있다. 현재 지식서비스의 형태로 중소기업에 제공되고 있는 서비스의 경우 창업지원, 연구개발 기획, 연구개발 수행, 기타 지원서비스에 이르기까지 중소기업 현장에서 일어나고 있는 기업 활동의 다양한 활동을 광범위하게 포함하고 있다. 이러한 지식서비스의 제공 현황과 범위는 지식서비스를 지원하는 기관의 특성에 따라 다소 차이를 보이고 있으나 대부분 핵심 서비스의 제공 측면에서는 유사한 성향을 보이며, 이는 각 지원기관의 특성에 따른 차별화가 부족하다는 것을 시사하고 있다. 그러나 지식서비스 제공 기관이 기관 특성 및 역량에 맞는 효과적 서비스를 제공하기 위해서는 핵심 지식서비스를 발굴하고 이를 중점적으로 제공하는 것이 필수적으로 요구된다. 따라서 본 연구에서는 다양한 중소기업 정책 및 지원사업을 제공하고 있는 KISTI 중소기업지식본부를 대상으로, 중소기업에 제공되어야 할 가장 적합한 지식서비스를 탐색하고, 핵심 지식서비스를 도출하며, 도출된 핵심 지식서비스에 대한 구체적인 서비스 모델을 제안하고자 한다.

• 창의정보문화연구
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• 제6권3호
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• pp.129-139
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• 2020

19세기 이후 다양한 분야의 과학기술이 거듭 성장하면서 의료분야에서도 보다 혁신적인 기술들이 높은 수준에까지 발전하고 있다. 융복합 기술의 촉진으로 인하여 실버계층을 위한 환자만족도 증진 시스템이 국내 메디컬 프로세스에 도입되고 있지만 기존 대형병원을 중심으로 한정적인 운용성을 유지하고 있으며, 서비스 시스템의 환경 여건 및 높은 경제적 비용으로 인하여 중소병원에서의 활용이 불가피한 실정이다. 그로인해 환자 만족도의 취약성 및 실버계층에 대한 서비스 접근성이 낮아지는 현상이 발생하게 된다. 본 논문에서는 HTK(Hidden Markov Model Toolkit)를 이용하여 일반 사용자는 물론 실버 계층과 같은 취약 계층까지 메디컬 서비스에 대한 사용자 접근성을 높일 수 있도록 하고 중소병원에서의 효율적인 환자 만족 서비스 관리가 가능하도록 하는 안드로이드 기반의 저비용 스마트 진료 정보서비스 시스템(Smart Medical treatment Information Service System)설계 기법을 제안한다.