• 경영과학
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• 제29권1호
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• pp.153-168
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• 2012

Order allocation is one of the most important decision-making problems of firms having significant influences on performances of themselves and the whole supply chain. Existing researches about order allocation have mainly focused on evaluating capabilities of directly connected suppliers so that it is hard to consider effects and interactions from undirected connections over multiple lower-layers. To alleviate the limitation, this paper proposed a novel approach to order allocation using structural hole. By applying the concept of structural hole to the supply network, we could evaluate the structural supplying powers of firms with respect to both of direct and indirect connections. In the proposed approach, we derived a methodology to measure the potential supplying power of each firm by modifying the effective size as one of the measurements of structural hole and then, proposed its application, the structural hole based order allocation strategy. Furthermore, we conducted the agent based modeling of supply chain to perform the decision-making process of order allocation and simulated the proposed strategy. As a results, by coping with the variance of demand more stably, it could improve the performance of supply chain from the aspects of fill rate, inventory level and demand-supply balance.

• 지능정보연구
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• 제20권4호
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• pp.107-120
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• 2014

본 연구에서는 사회연결망분석기법 중 하나인 구조적 공백 분석 결과를 이용하여 추천과정에 사용자의 정성적이고 감성적인 정보를 반영할 수 있는 협업필터링 기반의 추천시스템을 제안한다. 협업필터링은 추천기술 중 가장 많이 활용되고 있지만 전통적으로 확장성과 희박성 등의 문제점뿐 만 아니라 사용자-상품 매트릭스의 선호도만을 이용하여 추천을 함으로써 사용자의 정성적이고 감성적인 정보를 추천과정에 반영하지 못한다는 한계점이 있다. 본 연구에서 제안하는 추천시스템은 사회연결망분석에서 중심성 분석과 함께 연결망 내의 주요개체를 탐지할 수 있는 구조적 공백 분석을 이용하여 연결망 내의 대표 사용자들을 추출한 후 이들을 중심으로 군집을 형성한 후 각 군집색인 협업필터링을 수행하는 과정을 통해 전통적인 협업필터링에서 반영하지 못했던 정성적, 감성적 정보를 반영한다. 한편, 군집색인 협업필터링을 수행함으로써 추천의 효율성을 높일 수 있는 장점도 있다. 본 연구에서는 실제 사용자들의 상품에 대한 선호도 평가점수와 사용자들의 사회연결망 정보를 수집하여 실험을 수행하고 전통적인 협업필터링과 다양한 형태의 협업필터링과의 추천성과 비교를 통하여 제안하는 시스템의 유용성을 확인한다. 비교모형으로는 전통적인 협업필터링, 임의 군집색인 기반 협업필터링, k평균 군집색인 기반 협업필터링을 이용한 추천시스템이며, 실험 결과, 제안한 모형이 다른 비교모형에 비해 추천성과의 정확도가 가장 우수하였다. 추천성과의 차이에 대한 통계적 유의성 검정 결과, 제안 모형은 전통적인 협업필터링 기반의 추천시스템과는 통계적으로 유의한 성과 차이가 없었으나, 다른 두 모형에 대해서는 통계적으로 유의한 성과의 차이가 있는 것으로 나타났다.

• 디지털융복합연구
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• 제16권4호
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• pp.95-105
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• 2018

본 연구는 구미 클러스터내 기술지식 교류 네트워크에서 기술적 급진성에 대한 네트워크 폐쇄와 구조적 공백의 역할을 실증적으로 검증한 연구이다. 분석을 위해 협회*기업(2-mode)네트워크 자료를 기업*기업(1-mode) 네트워크 자료로 변환하여 2,550개 기업 네트워크를 구축하였다. 또한 기업의 특성을 조사하기 위해 구미국가산업단지에 있는 기업을 대상으로 랜덤추출을 통해 101개 기업에게 설문을 실시하였으며 최종적으로는 86개 기업을 수집하였다. 분석을 위해, 네트워크 폐쇄와 구조적 공백의 사회네트워크 분석 지표인 네트워크 밀도와 효율성이 높은 수준의 다중공선성을 갖고 있어 능형회귀분석을 이용하였다. 분석결과 구조적 공백은 기업의 급진적 혁신에 긍정적인 영향을 미치는 것으로 나타났으며, 네트워크 밀도는 급진적 혁신에 부정적인 영향을 미치는 것으로 나타났다. 본 연구는 과거의 개념적인 논의와 문헌연구에 기반 했던 네트워크 패쇄와 구조적 공백의 논쟁에 실증적 증거 제시하는데 공헌하고 나아가 급진적 혁신을 달성하기 위한 사회적 자본의 구축 전략 수립에 도움을 준다. 향후 연구에서는 다양한 네트워크의 구조적 특성을 찾아내려는 노력이 필요할 것이며, 기술 지식의 특성, 혁신 유형, 네트워크 폐쇄와 구조적 공백의 상호작용 등에 관심을 두어야 할 것이다.

• Structural Engineering and Mechanics
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• 제63권3호
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• pp.269-280
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• 2017

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권4호
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• pp.353-361
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• 2012

All current shipyards are using the customized CAD/CAM programs in order to improve the design quality and increase the design efficiency. Even though the data structures for ship design and construction are almost completed, the implementation related to the ship design processes are still in progress so that it has been the main causes of the bottleneck and delay during the middle of design process. In this study, we thought that the hole-plan system would be a good example which is remained to be improved. The people of outfitting division who don't have direct authority to edit the structural panels, should request the hull design division to install the holes for the outfitting equipment. For acceptance, they should calculate the hole position, determine the hole type, and find the intersected contour of panel. After consideration of the hull people, the requested holes are manually installed on the hull structure. As the above, many processes are needed such as communication and discussion between the divisions, drawings for hole-plan, and the consideration for the structural or production compatibility. However this iterative process takes a lot of working time and requires mental pressure to the related people and cross-division conflict. This paper will handle the hole-plan system in detail to automate the series of process and minimize the human efforts and time-consumption.

• 대한토목학회논문집
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• 제7권4호
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• pp.115-124
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• 1987

본 연구는 피로균열이 발생한 부재의 응급적인 보수, 보강방법으로 예로부터 실제로 이용되어 온 stop-hole에 대하여 그 보수, 보강효과를 잔존수명의 관점에서 정량적인 평가를 시도한 것이다. 이를 위하여 대상 시험편에 대한 피로시험을 실시하여 그 피로거동을 검토한 결과, 피로균열에 대한 응급조치로서 stop-hole을 이용할 경우, 균열이 탄소성 거동을 하는 영역에 이르기 전에 처리하는 것이 바람직함을 알 수 있었다.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2475-2482
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• 2002

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.412-418
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• 2001

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is corrected using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could corrected the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for correction of the error due to hole eccentricity in hole-drilling method.

• 대한기계학회논문집A
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• 제24권8호
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• pp.2059-2064
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• 2000

The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, one of the source of error is due to the misalignment between the drilling hole and strain gage center. This paper presents a finite element analysis of the influence of such misalignment for the uniaxial residual stress field. The stress error increases proportionally to hole eccentricity. The correction equations which easily obtain the residual stress taking account of the hole eccentricity are derived. The stress error due to the hole eccentricity decreases by approximately one percent using this equations.

• Structural Engineering and Mechanics
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• 제67권2호
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• pp.131-142
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• 2018

The perfobond connector, composed of a steel plate with a number of holes, serves as a certain type of shear connector in steel and concrete composite structures. Depending on limits in hole distances and rib heights, various hole shapes including circular-hole and long-hole are alternatives for perfobond connectors. This study presented the results of tests performed on 72 push-out specimens with perfobond connectors. The purpose was to evaluate the shear strength of perfobond connectors with circular-hole and long-hole. The effects of various parameters were investigated, including the hole diameter, the hole length, the hole height, the concrete strength, the existence, diameter and strength of rebar in the hole, the thickness, height and distance of perfobond ribs, and the thickness of concrete slabs. On the basis of 132 push-out test results in references and in this study, an analytical model was proposed by regression analysis to predict the shear strength of perfobond connectors. The proposed equation agreed reasonably well with the experimental results of perfobond connectors with different hole shapes.