• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.811-812
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• 2016

최근 공간 정보는 생산 되는 양과 데이터의 생성 빈도 및 다양성으로 인해 기존의 공간 데이터베이스 시스템에서 처리하기 어렵다. 그래서 공간 정보는 빅데이터와 연계에 관한 시도가 활발히 진행되고 있다. 그러나 효율적인 단일할당, 다중할당 색인기반 공간 연산에 대한 연구는 거의 없다. 이 논문에서는 공간 연산 중 비용이 매우 큰 공간 조인을 빅데이터 시스템에서 처리하기 위한 고려요소를 제시하고자 한다. 구체적으로 맵리듀스 시스템의 태스크 할당을 위한 단일 할당 공간 색인방안을 설명하고, 불균일 분포가 심한 공간 정보의 특성을 고려한 부하 균등화 시 고려 요소를 제시하고자 한다. 맵리듀스와 같은 병렬 공간 데이터베이스 시스템에서의 두 가지 문제인 데이터 불균일 분포 문제와 경계 겹침 색인의 문제와의 연관성을 기술한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.194-200
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• 2013

In this paper, the results of composite laminate mechanical joints test(ASTM D5961) are compared with the theoretical strength calculations and FEM analysis results. To calculate the S.C.F.(stress concentration factor) on joint strength, equations on metallic and composite materials in ASM Handbook used and compared with experimental results. The difference of joint strength are compared by geometrical parameters and joining types(single/double lap joint). In FEM analysis, to find efficient FEM model on composite laminate mechanical joint, several FEM models are compared with experimental test results.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.98-106
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• 2013

In this paper, we propose a moving object detection and tracking method for multi-view camera environment. Based on the similarity and characteristics of motion vectors and coding block modes extracted from compressed bitstreams, validation of moving blocks, labeling of the validated blocks, and merging of neighboring blobs are performed. To continuously track objects for temporary stop, crossing, and overlapping events, a window based object updating algorithm is proposed for single- and multi-view environments. Object detection and tracking could be performed with an acceptable level of performance without decoding of video bitstreams for normal, temporary stop, crossing, and overlapping cases. The rates of detection and tracking are over 89% and 84% in multi-view environment, respectively. The rates for multi-view environment are improved by 6% and 7% compared to those of single-view environment.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.273-275
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• 2011

최근 교통량이 증가함에 따라 자동차 사고피해도 비례하여 증가하고 있으며, 이로 인해 CCTV 등과 같이 교통사고 예방에 소모되는 비용이 막대하게 지출되고 있다. 단일시점 카메라의 시스템은 객체들의 겹침, 카메라각도에 의한 인식오류 등으로 오차율이 높은 단점이 있다. 이를 보완하기 위해 다중시점의 협업기반 자동 상황인지 시스템을 제안한다. 제안하는 방법은먼저 영상데이터로부터 차량, 사람 등의 객체를 추출하고 이들 객체 쌍의 특징 정보를 계산한다. 이를 바탕으로 각 카메라 센서노드의 규칙기반 시스템을 이용하여 객체간의 사고여부를 가려낸다. 각 센서노드의 사고여부 정보는 메인서버로 수집되고, 수집된 정보는 상위 규칙에 의해 최종 사고 여부가 판단된다. 본 논문에서는 실제 교차로에 설치된세대의 카메라를 이용한 실험을 통해 제안하는 시스템의 성능을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.834-835
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• 2016

가상공간 내에서 다중사용자 간에 NUI를 기반으로 상호작용하기 위한 기반 기술로 사용자 식별 연구가 활발이 수행되고 있다. 이 때 단일 센서만을 이용할 경우 센싱 범위의 한계와 가림 및 겹침으로 인해 사용자의 정확한 특징데이터를 인식하기 어렵다. 이러한 문제점을 해결하기 위하여 멀티 센서를 이용한 사용자 식별 시스템을 제안한다. 제안한 시스템을 설계 및 구현한 결과, 다중 사용자 개개인에 대한 식별이 가능함을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.69-75
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• 2014

Existing People Counting System using a single overhead mounted camera has limitation in object recognition and counting in various environments. Those limitations are attributable to overlapping, occlusion and external factors, such as over-sized belongings and dramatic light change. Thus, this paper proposes the new concept of People Counting System by Facial Age Group using two depth cameras, at overhead and frontal viewpoints, in order to improve object recognition accuracy and robust people counting to external factors. The proposed system is counting the pedestrians by five process such as overhead image processing, frontal image processing, identical object recognition, facial age group classification and in-coming/out-going counting. The proposed system developed by C++, OpenCV and Kinect SDK, and it target group of 40 people(10 people by each age group) was setup for People Counting and Facial Age Group classification performance evaluation. The experimental results indicated approximately 98% accuracy in People Counting and 74.23% accuracy in the Facial Age Group classification.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.111-118
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• 2010

The joints are often the weakest areas in composite structures. In this paper, the thick aluminum-aluminum joint specimens and thick composite-aluminum single lap adhesive joint specimens were manufactured and the tensile tests were performed. The fracture mode of each specimen was investigated and the modified damage zone theory based on the yield strain was proposed and compared with experimental failure load of each mode. The failure loads of the thick aluminum-aluminum joint and composite-aluminum joint were predicted by the same failure criterion and they could be predicted to within 19.3% using the damage zone ratio method for all 14 cases investigated.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.120-123
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• 2013

본 논문에서는 키넥트 센서의 RGB영상을 이용하여 얼굴을 검출하고 검출된 영역의 깊이정보를 템플릿으로 사용하여 다수개의 얼굴을 추적하는 방법을 제안한다. 이 논문은 [1]의 단일 얼굴 추적방법을 다수의 얼굴을 추적하도록 확장한 것이다. 다수의 얼굴추적을 실시간으로 처리하기 위하여 영상을 down sampling 하여 사용한다. 얼굴 검출은 기본적으로 기존의 Adaboost 방법을 사용하나, 피부색만을 이용, 탐색영역을 최대한 축소하여 수행 시간 및 오검출율을 줄인다. 얼굴추적은 깊이정보를 템플릿으로 하며, 깊이값에 따라 크기, 탐색영역을 조정하고, 또한 일정 프레임마다 얼굴을 검출하며 겹침, 새로 나타남, 영상 밖으로 사라짐 등의 얼굴추적 시 발생하는 문제를 해결한다.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.488-498
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• 2007

This paper presents a novel approach for representing the spatio-temporal topology of the camera network with overlapping and non-overlapping fields of view (FOVs) in Ubiquitous Smart Space (USS). The topology is determined by tracking moving objects and establishing object correspondence across multiple cameras. To track people successfully in multiple camera views, we used the Merge-Split (MS) approach for object occlusion in a single camera and the grid-based approach for extracting the accurate object feature. In addition, we considered the appearance of people and the transition time between entry and exit zones for tracking objects across blind regions of multiple cameras with non-overlapping FOVs. The main contribution of this paper is to estimate transition times between various entry and exit zones, and to graphically represent the camera topology as an undirected weighted graph using the transition probabilities.

• Journal of Yeungnam Medical Science
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• v.32 no.2
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• pp.80-84
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• 2015

Background: Rotavirus is the most common cause of severe gastroenteritis in children <5 years of age. The first vaccine, RotaShield was developed, but withdrawn because of its association with increased risk of intussusception. Then, RotaTeq and Rotarix were developed. Although in pre-licensure studies, they were not associated with an increased risk of intussusceptions, in recent studies, it has been controversial. Regarding increased risk of intussusception, we studied the difference in the age of intussusception after rotavirus vaccination. Methods: A retrospective analysis was conducted on 136 patients diagnosed with intussusception at Yeungnam University Medical Center for 4 years in the pre-vaccination period (group A) and in the post vaccination period (group B). Sex, mean age and age distribution of intussusceptions were compared according to the type of rotavirus vaccine (group B-1, RotaTeq; group B-2, Rotarix). Results: The median ages of group A and group B were $18.8{\pm}19.6months$ and $15.5{\pm}10.2months$, with no significant differences (p=0.23). The median ages of group B-1 and group B-2 were $15.3{\pm}9.3months$ and $15.6{\pm}10.8months$, with no significant differences (p=0.91). And No significant difference in the distribution of onset age was observed between groups, and only 6 patients were diagnosed with intussusceptions within 1 month after vaccination. Conclusion: No difference was observed in the distribution of onset age of intussusception after rotavirus vaccination and according to the type of rotavirus vaccine. Our study has a limitation in that it was conducted in part of the Daegu area. Additional study is needed.