• Journal of KIISE:Databases
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• v.31 no.5
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• pp.479-491
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• 2004

Location information of mobile objects is applied to vehicle tracking, digital battlefields, location based services, and telematics. Their location coordinates are periodically measured and stored in the application systems. The linear function is mainly used to estimate the location information that is not in the system at the query time point. However, a new method is needed to improve uncertainties of the location representation, because the location estimation by linear function induces the estimation error. This paper proposes an application method of the cubic spline interpolation in order to reduce deviation of the location estimation by linear function. First, we define location information of the mobile object moving on the two-dimensional space. Next, we apply the cubic spline interpolation to location estimation of the proposed data model and describe algorithm of the estimation operation. Finally, the precision of this estimation operation model is experimented. The experimentation comes out more accurate results than the method by linear function, although the proposed location estimation function uses the small amount of information. The proposed method has an advantage that drops the cost of data storage space and communication for the management of location information of the mobile objects.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.55-68
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• 2014

Some infrastructure these days is usually constructed under the ground for it to not interfere the foot-traffic of pedestrians, and thus, it is difficult to visually confirm the accurate location of the site where the establishments must be buried. These technical difficulties increase the magnitude of the problems that could arise from over-reliance on the experience of the worker or a mere blueprint. Such problems include exposure to flood and collapse. This paper proposes a constructor-oriented visualization system via mobile gadgets in general construction sites with occluded structures. This proposal is consisted with three stages. First, "Stage of detecting manhole and extracting features" detects and extracts the basis point of occluded structures which is unoccluded manhole. Next, "Stage of tracking features" tracks down the extracted features in the previous stage. Lastly, "Stage of visualizing occluded constructions" analyzes and synthesizes the GPS data and 3D objects obtained from mobile gadgets in the previous stages. This proposal implemented ideal method through parallel analysis of manhole detection, feature extraction, and tracking techniques in indoor environment, and confirmed the possibility through occluded water-pipe augmentation in real environment. Also, it offers a practical constructor-oriented environment derived from the augmented 3D results of occluded water-pipings.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.20-28
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• 2010

In this paper, we propose a hand gesture interface for the manipulation of augmented objects in 3D space using a camera. Generally a marker is used for the detection of 3D movement in 2D images. However marker based system has obvious defects since markers are always to be included in the image or we need additional equipments for controling objects, which results in reduced immersion. To overcome this problem, we replace marker by planar hand shape by estimating the hand pose. Kalman filter is for robust tracking of the hand shape. The experimental result indicates the feasibility of the proposed algorithm for hand based AR interfaces.

• Journal of KIISE
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• v.43 no.3
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• pp.353-361
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• 2016

During image-guided radiation treatment of lung cancer patients, it is necessary to track the tumor motion because it can change during treatment as a consequence of respiratory motion and cardiac motion. In this paper, we propose a method for tracking the motion of the lung tumors based on the three-dimensional image information from planning 4D MDCT and treatment 4D CBCT images. First, to effectively track the tumor motion during treatment, the global motion of the tumor is estimated based on a tumor-specific motion model obtained from planning 4D MDCT images. Second, to increase the accuracy of the tumor motion tracking, the local motion of the tumor is estimated based on the structural information of the tumor from 4D CBCT images. To evaluate the performance of the proposed method, we estimated the tracking results of proposed method using digital phantom. The results show that the tumor localization error of local motion estimation is reduced by 45% as compared with that of global motion estimation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.164-165
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• 2017

본 논문에서는 고속의 이동체를 추적하기 위하여 적외선 스테레오 카메라 시스템을 이용하였다. 열원을 감지할 수 있는 적외선 카메라를 이용해 고온의 추진체를 찾는다, 그리고 고속 이동체의 3 차원 위치를 계산하기 위해 스테레오 카메라 시스템을 사용하여 카메라와 고속 이동체 사이의 거리를 계산하였다. 마지막으로 인공신경망을 이용한 회귀분석으로 고속 이동체의 궤적을 추정하였다. 제안한 시스템이 동작하는 것을 실험 결과를 통해 보인다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.724-728
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• 2010

강우강도의 증가와 식생대의 변화 등 기후변화로 인한 저수지내 대형탁수와 조류대발생으로 사회적 문제가 야기되고 있다. 이에 유역대책 평가와 저수지내 유체거동 및 영향평가를 위한 수단 확보가 절실한 상황이다. 본 연구에서는 국내 저수지에 대한 3차원 수리해석기술의 적용성을 검토하고자 하였다. 이를 위해 낙동강의 주요지류 중 하나인 남강에 위치한 남강댐에 대해 미 EPA의 오염총량지원도구인 EFDC 모델을 적용하였다. 저수지내 퇴사량 조사시 측정된 실측치와의 지형 재현성 검토, 실측수위와 모의결과의 비교를 그래프와 통계지표를 활용하여 실시하였고 염료 추적 모의를 통해 도달시간 등을 산정하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.4
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• pp.505-513
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• 2009

Recently, researches on the construction information for construction of high-tech cities are under performed. RTLS(Real-Time location system) for gathering the dynamic location information of construction resources in construction sites, such as workers, materials and equipments, is one of the developments. Especially, construction resources can be managed efficiently with the dynamic location information and the improvement of safety and the reduction of cost are expected. To introduce the RTLS to the construction sites, the installation location of AP(Access Point) must be simulated using the 3-dimensional visibility analysis considering the propagation distance of AP. In this research, 3-dimensional signal simulation software based on the spatial data using surveying terrestrial LiDAR is developed. The simulated results are compared with the signal strength of field experiments for 4 test sites. As a result, the signal strength from the propagation model is most similar to that of field experiment at the front of the main building and the maul playground of Konkuk University. The visibilities in that sites are higher than other sites. among 4 test sites.

• Journal of KIISE:Databases
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• v.36 no.3
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• pp.198-214
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• 2009

Trajectories of RFID tags can be modeled as a line, denoted by tag interval, captured by an RFID reader and indexed in a three-dimensional domain, with the axes being the tag identifier (TID), the location identifier (LID), and the time (TIME). Distribution of tag intervals in the domain space is an important factor for efficient processing of a query for tracing tags and is changed according to arranging coordinates of each domain. Particularly, the arrangement of LIDs in the domain has an effect on the performance of queries retrieving the traces of tags as times goes by because it provides the location information of tags. Therefore, it is necessary to determine the optimal ordering of LIDs in order to perform queries efficiently for retrieving tag intervals from the index. To do this, we propose LID proximity for reordering previously assigned LIDs to new LIDs and define the LID proximity function for storing tag intervals accessed together closely in index nodes when a query is processed. To determine the sequence of LIDs in the domain, we also propose a reordering scheme of LIDs based on LID proximity. Our experiments show that the proposed reordering scheme considerably improves the performance of Queries for tracing tag locations comparing with the previous method of assigning LIDs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.1-7
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• 2012

At the industrial work site, the manufacturing process is being automated to improve work efficiency. However, it is often difficult to automate the entire manufacturing process, and there are spaces in which workers there are constantly exposed to danger. To protect such workers from the danger, this paper studied a worker safety management system for the industrial work site which uses a location recognition system and which is based on the Ubiquitous-Wireless Sensor Network (U-WSN). Using wireless signals, the distance between two devices can be measured and the location of a worker can be calculated using triangularization in 3-D. But at the industrial work sites where there are a lot of steel and structures, errors occur due to signal reflection and multi-path, etc., which makes it difficult to get the accurate location. To address this problem the following was done: first, a circular polarization patch antenna appropriate to the work site was used to reduce the degree of error that may occur from the antenna emission pattern and the particular Line of Sight (LOS); second, a 3-D localization technique and a filtering algorithm were used to improve the accuracy of location determination. The developed system was tested by using it on a wharf crane to validate its accuracy and effectiveness. The proposed location recognition system is expected to contribute greatly in ensuring the safety of workers at industrial work sites.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.209-212
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• 2005

모션 캡쳐 기술은 영화나 게임 혹은 애니메이션과 같은 다양한 분야에서 새롭게 시도되고 있다. 기존의 모션 캡쳐 방식은 마커라는 불편한 인식장치로 인하여 움직임에 적지 않은 제약을 받을 뿐만 아니라 엄청난 고가 장비를 필요로 한다. 갈수록 좀 더 편리한 모션 캡쳐 기술이 요구됨에 따라 실시간으로 물체의 위치를 트래킹(위치추적)하고, 스테레오 비전을 이용하여 3 차원 재 구축을 수행해 입체적인 가상모델을 생성하여 보았다. 본 논문에서는 효율적인 트래킹 연산에 의한 움직임 제약을 최소화한 개선된 알고리즘을 설계, 구현하였고, 저렴한 웹 캠을 이용하여 스테레오 비전방식(Stereo Vision Based)을 접목시켜 기존의 고가 장비들과 유사한 환경을 이 시스템으로도 가능하다는 것을 확인하였다.