• 한국농공학회논문집
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• 제64권5호
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• pp.67-77
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• 2022

Recently, the trend in structural analysis and design is moving towards the development of reliable system. The reliability-based method defines various limit states related to usability and failure, thereby enabling multiple levels of design according to the importance of a structure. Meanwhile, an actual structure is composed of a set of several elements, and particularly, a frame type is composed of a system in which the members are connected each other. At this time, the actual connection between members is in a semi-rigid condition, not in complete rigid or hinged. This semi-rigid is found in several structures, especially in agricultural facilities designed with lightweight materials. In this study, a system reliability analysis technique for frame structure was established, and applied to an analysis of the semi-rigid connection. Various conditions of correlation were applied to reflect the connectivity between members, and through this, the limitations of existing structural analysis method and the behavioral characteristics of structure were analyzed. The failure probability of the frame member component and the overall structure system was significantly different in consideration of the semi-rigid connection. In addition, it was evaluated that the behavior of structure can be more accurately analyzed if the correlation according to the position of members in a system is further investigated.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.413-415
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• 2022

인간의 관절은 인간의 신체를 구성하는 요소로 인간의 행동을 분석하는데 유용한 정보로 활용될 수 있기 때문에 관절 정보를 이용한 행동인식에 대한 많은 연구가 진행되었다. 하지만 각각의 독립적인 관절 정보만을 이용해서 시시각각 변화하는 인간의 행동을 인식하는 것은 매우 복잡한 문제이다. 따라서 학습에 사용할 부가적인 정보 추출 방법과 과거의 상태를 기반으로 현재 상태를 판단하는 고려하는 알고리즘이 필요하다. 본 논문에서는 연결된 관절들의 위치 관계와 각 관절의 위치가 시간의 흐름에 따라 변화하는 것을 고려한 행동 인식 기법을 제안한다. 사전 학습된 관절 추출 모델을 이용하여 각 관절의 위치 정보를 획득하고 연결된 관절 사이의 차 벡터를 이용하여 뼈대 정보를 추출한다. 그리고 두 가지 형태의 입력에 맞춰 간소화된 신경망을 구성하고 LSTM을 더하여 시·공간적 특징을 추출하도록 한다. 9개의 행동으로 구성된 데이터 셋을 이용하여 실험한 결과 각 관절 및 뼈대의 시·공간적 관계 특징을 고려하여 행동 인식 정확도를 측정하였을 때 단일 관절 정보만을 이용한 결과에 비해 뛰어난 성능을 보임을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제14권5호
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• pp.45-54
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• 2009

본 논문에서는 평균 명암 필터와 개선된 2D 허프 변환을 이용하여 영상에서 가슴 영역을 검출함으로써 음란영상을 탐지하는 새로운 방법을 제안한다. 제안된 유해물 영상 검출 방법은 크게 학습 단계, 인식 단계, 검증 단계의 3가지 주요 단계로 구성된다. 학습 단계에서는 가슴의 유두 부분 영상의 학습을 통하여 인식 단계에서 사용할 유두 평균 명암 필터를 생성한다. 인식 단계에서는 입력 영상을 받아들여 에지를 추출하고, 에지의 밀도를 이용해 연결성분을 추출한 후. 추출된 연결성분의 가로와 세로외 길이 비율을 고려하여 유두 후보영역을 결정한다. 그리고 학습된 유두 평균 명암 필터와 입력 영상의 유두 후보영역 사이의 유사도를 측정하여 가장 유사도가 높은 영역을 최종적인 유두후보영역으로 결정하며, 개선된 2D 허프 변환을 이용하여 영상에서 가슴 라인을 검출한다. 검증 단계에서는 인식 단계에서 획득한 유두 후보영역과 가슴 라인의 위치를 고려하여 가슴 영역을 판단함으로써 유해물 영상의 최종 유무를 결정한다. 실험 결과에서는 다양한 영상을 이용한 실험을 통해 제안한 방법이 가슴 영역을 효과적으로 인식할 수 있음을 보여 주었으며, 결과적으로 제안된 방법이 음란 영상의 검출에 유용하게 활용될 수 있음을 확인할 수 있었다.

• 한국작물학회지
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• 제38권1호
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• pp.31-37
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• 1993

우리나라 주요 벼 재배품종 및 신육성계통(자포니카: 25품종, 통일형:8품종)에 대한 쌀 알칼리 붕괴성의 품종적 특이성을 분시검토하여 보고자 KOH 농도를 0.8-1.8까지 0.2% 간격으로 처리하여 농도별 쌀의 알칼리 붕괴반응을 조사하고 주성분분석법을 적용하여 품종적 유형을 분류하였다. 주성분분석에서 상위 2개 주성분치의 변이가 전변이량의 92%을 차지하였고 제1 및 제2 주요분치 좌표상의 품종분포에 따라 크게 4개 유형으로 군집화 시킬 수 있었다. 제 I 군에서는 전 KOH 농도에 걸쳐 거의 비슷하게 알칼리 붕괴성(ADV)가 낮은 도봉벼만 유일하게 분포하였고, 제 II군에는 1.4% KOH 농도에서 중간정도의 ADV 이면서 고-저 알칼리 농도 ADV간차가 중도인 백운찰벼, 신선찰벼 및 수원 34002 등 찰벼가 포함되어 있었다. 제 III군에는 1.4% KOH 농도에서 중-중고의 ADV 이면서 저-고 KOH 농도간 ADV 변화가 심했던 대부분의 통일형 품종과 자포니카 조생계가 분포되어 있었고 육도농림찰 001와 한강 찰벼등은 이 유형에 포함되어 있었다. 제 IV군에는 1.4% KOH 농도에서 ADV가 중고이상으로 높으면서 고-저 알칼리 농도 ADV간차가 중-중고인 중생 및 중만생 자포니카 품종들이 주로 분포 하였으며 조생인 금조벼가 이 유형에 속하였다. 여기서 제 1 주성분은 전 알칼리 농도에서 평균적으로 표현되는 붕괴성 정도였고 제 2 주성분은 저-고 KOH 농도의 ADV간 차 또는 KOH 농도에 따른 ADV 변화의 회귀계수와 밀접하게 관련된 요소였다. 1.2%-1.4% KOH 농도에서의 ADV는 저-고 KOH 농도간 ADV차와 2차 곡선 회귀계수를 나타내었다.

• 한국통신학회논문지
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• 제38C권12호
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• pp.1114-1125
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• 2013

License Plate Detection (LPD) is a key component in automatic license plate recognition system. Despite the success of License Plate Recognition (LPR) methods in the past decades, the problem is quite a challenge due to the diversity of plate formats and multiform outdoor illumination conditions during image acquisition. This paper aims at automatical detection of car license plates via image processing techniques. In this paper, we proposed a real-time and robust method for license plate detection using Heuristic Energy Map(HEM). In the vehicle image, the region of license plate contains many components or edges. We obtain the edge energy values of an image by using the box filter and search for the license plate region with high energy values. Using this energy value information or Heuristic Energy Map(HEM), we can easily detect the license plate region from vehicle image with a very high possibilities. The proposed method consists two main steps: Region of Interest (ROI) Detection and License Plate Detection. This method has better performance in speed and accuracy than the most of existing methods used for license plate detection. The proposed method can detect a license plate within 130 milliseconds and its detection rate is 99.2% on a 3.10-GHz Intel Core i3-2100(with 4.00 GB of RAM) personal computer.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1029-1039
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• 2013

To avoid undesirable disconnection of healthy wind generators (WGs) or a wind power plant, a WG protection relay should discriminate among faults, so that it can operate instantaneously for WG, connected feeder or connection bus faults, it can operate after a delay for inter-tie or grid faults, and it can avoid operating for parallel WG or adjacent feeder faults. A WG protection relay based on the positive- and negative-sequence fault components is proposed in the paper. At stage 1, the proposed relay uses the magnitude of the positive-sequence component in the fault current to distinguish faults requiring non-operation response from those requiring instantaneous or delayed operation responses. At stage 2, the fault type is first determined using the relationships between the positive- and negative-sequence fault components. Then, the relay differentiates between instantaneous operation and delayed operation based on the magnitude of the positive-sequence fault component. Various fault scenarios involving changes in position and type of fault and faulted phases are used to verify the performance of the relay. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. Results indicate that the relay can successfully distinguish the need for instantaneous, delayed, or non-operation.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.83-86
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• 1996

In this paper we study the problem of augmenting a physical network to improve the topology for new survivable network architectures. We are given a graph G=(V,E,F), where V is a set of nodes that represents transmission systems which be interconnected by physical links, and E is a collection of edges that represent the possible pairs of nodes between which a direct transmission link can be placed. F, a subset of E is defined as a set of the existing direct links, and E/F is defined as a set of edges for the possible new connection. The cost of establishing network $N_{H}$=(V,H,F) is defined by the sum of the costs of the individual links contained in new link set H. We call that $N_{H}$=(V,H,F) is feasible if certain connectivity constrints can be satisfied in $N_{H}$=(V,H,F). The computational goal for the suggested model is to find a minimum cost network among the feasible solutions. For a k edge (node) connected component S .subeq. F, we charactrize some optimality conditions with respect to S. By this characterization we can find part of the network that formed by only F-edges. We do not need to augment E/F edges for these components in an optimal solution. Hence we shrink the related component into a node. We study some good primal heuristics by considering construction and exchange ideas. For the construction heuristics, we use some greedy methods and relaxation methods. For the improvement heuristics we generalize known exchange heuristics such as two-optimal cycle, three-optimal cycle, pretzel, quezel and one-optimal heuristics. Some computational experiments show that our heuristic is more efficient than some well known heuristics.stics.

• 한국수학사학회지
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• 제31권2호
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• pp.73-91
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• 2018

This study begins with the awareness of problem that the education of mathematics teachers has failed to link the limit and the infinite set conceptually. Thus, this study analyzes the historical and reciprocal development of the limit and the infinite set, and discusses how to improve the education of these concepts and their relation based on the outcome of this analysis. The results of the study confirm that the infinite set is the historical tool of linking the limit and the real numbers. Also, the result shows that the premise of 'the component of the straight line is a point.' had the fundamental role in the construction of the real numbers as an arithmetical continuum and that the moral certainty of this premise would be obtained through a thought experiment using an infinite set. Based on these findings, several proposals have been made regarding the teacher education of awakening someone to the fact that 'the theoretical foundation of the limit is the real numbers, and it is required to introduce an infinite set for dealing with the real numbers.' in this study. In particular, by presenting one method of constructing the real numbers as an arithmetical continuum based on a thought experiment about the component of the straight line, this study opens up the possibility of an education that could get the limit values psychologically connected to the infinite set in overcoming the epistemological obstacle related to the continuum concept.

• 산경연구논집
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• 제9권2호
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• pp.47-55
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• 2018

Purpose - To meet the needs of various customers in an uncertain market environment, many companies use product modularization strategies. Modularization of a product means that one product consists of several components and that the type of product can be changed according to the combination of components. The greatest feature of modularity is that changes in one component do not significantly affect the physical changes in the other component to which they are connected. Modularization of products is recognized as a very important strategy to reflect increasingly complicated customer requirements to products and respond to the needs of various markets. Many studies have been made in connection with the concept of mass customer satisfaction. There are many prior studies that modularization of such products positively affects the operational performance (manufacturing cost, fast delivery, etc.) and innovation of the product. However, excessive modularization has been found to have a negative effect on this performance. However, there are very few studies on the nonlinear relationship between product modularization and customer satisfaction. Supplementing these academically insufficient parts is very necessary when considering the current market environment. Research design, data, and methodology - In order to make up for the shortcomings of academic research in Korea, this study collects data through questionnaires in electronic, auto, and defense industry. This is because these industries are using modularity of products. based on lots of previous studies and information overload theory, we made two hypothesis and verify with empirical analysis. All 108 data were used. We used the R program and SPSS program for statistical verification. Results - As a result of the study, modularization of products showed positive relationship with customer satisfaction to a certain level. However, it has been found that when the modularization is over and beyond a certain level, there is a negative relationship with customer satisfaction. Conclusions - Excessive modularization of products can have a negative impact on customer satisfaction. This result can be understood as a result of human limited rationality due to information overload. Therefore, it is important for companies to apply appropriate modularity to product design.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.361-371
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• 2014

PURPOSE. In case of large horizontal discrepancy of alveolar ridge due to severe resorption, cantilevered crown is usually an unavoidable treatment modality. The purpose of this study was to evaluate the clinical criteria for the placement of the aforementioned implant crown. MATERIALS AND METHODS. The mandible model with 2 mm thick cortical bone and cancellous bone was fabricated from CT cross-section image. An external connection type implant was installed and cantilevered crowns with increasing offset of 3, 4, 5, 6, and 7 mm were connected. Vertical load and $30^{\circ}$ oblique load of 300 N was applied and stress around bone and implant component was analyzed. A total of 14 cases were modeled and finite element analysis was performed using COSMOS Works (Solid works Inc, USA). RESULTS. As for the location of the vertical load, the maximum stress generated on the lingual side of the implant became larger according to the increase of offset distance. When the oblique load was applied at $30^{\circ}$, the maximum stress was generated on the buccal side and its magnitude gradually decreased as the distance of the offset load increased to 5 mm. After that point, the magnitude of implant component's stress increased gradually. CONCLUSION. The results of this study suggest that for the patient with atrophied alveolar ridge following the loss of molar teeth, von-Mises stress on implant components was the lowest under the $30^{\circ}$ oblique load at the 5 mm offset point. Further studies for the various crown height and numbers of occusal points are needed to generalize the conclusion of present study.