• Journal of KIISE:Databases
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• v.29 no.1
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• pp.72-78
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• 2002

The distance join is a spatial join which finds data pairs in the order of distance between two spatial data sets using R-trees. The distance join stores node pairs in a priority queue, which are retrieved while traversing R-trees in a top-town manner, in the order of distance. This paper first shows that a priority strategy for the tied pairs in the priority queue during distance join processing has much effect on its performance, and then proposes an optimized secondary priority method. The experiments show that the proposed method is always better than the other methods in the performance perspectives.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.373-383
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• 2001

The distance join is a spatial join which finds data pairs in the order of distance when associating two spatial data sets. This paper proposes several methods to optimize the adaptive multi-stage distance join, presented in [1]. First, we optimize the sweeping index formula which is used for selecting sweeping axis during plane sweeping. Second, to improve the performance of a priority queue used for maintaining node pairs, we propose to use the maximum distance of a node pair as the second priority of the queue. Moreover, we compare trade-offs in estimating the cut-off distance between under uniformity assumption of data distribution and non-uniformity assumption. The experiments show that the proposed methods greatly improve the performance of the algorithm in CPU cost as well as in I/O cost.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.242-243
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• 2018

무선 통신기술이 발전함에 따라 위치기반 서비스에 대한 관심 또한 증가하고 있다. 그 중 저전력 블루투스 기술을 사용한 비콘(Beacon)은 실내 위치인식이 불가능한 GPS와 달리 실내에서도 측위가 가능하여 사용성이 주목 받고 있다. 그러나 비콘으로부터 수신되는 RSSI(Received Signal Strength Indication) 값은 여러 환경요소로부터 영향을 받기 때문에 RSSI값을 기반으로 한 거리측정이 실제거리와의 오차가 크게 나타난다. 이에 따른 문제를 해결하기 위한 기존의 연구들이 존재하지만 평균적으로 10m이하의 거리에서 2m의 오차를 나타내고 있다. 본 연구에서는 RSSI의 오차를 줄이기 위해 확장 칼만 필터와 신호 안정화 필터를 사용하여 Raw Data를 전처리 한 후 산출된 Cleaned Data를 기반으로 각 거리단위에 최적화된 ANN(Artificial Neural Network)모델을 생성하여 거리를 측정하는 기법을 제안한다.

• 한국지형공간정보학회:학술대회논문집
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• 1993.10a
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• pp.141-145
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• 1993

A new digital change detection algorithm, Euclidean Distance Analysis, was developed in an attempt to utilize the multi-band information in a selected band-comination, as an alternative to the conventional single-band analysis methods. To evaluate the relative performance of this new method, image differencing was applied. The better performance in change detection between the two algorithms investigated was provided by the Euclidean distance analysis. The new technique of Euclidean distance analysis holds promise for change detection, since it summarizes the multiple-band information on the cover-type changes and reduces the data dimensionality. It is suggested to further evaluate this new method, quantitatively, in the different environments. The use of different accuracy indices was also examined in the determining the optimal threshold level for each change image. As the standard measure for classification accuracy, the Kappa coefficient of agreement was used for evaluation.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.129-138
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• 2002

In this paper, a distance measuring algorithm for motion capture using color stereo camera is proposed. The color markers attached on articulations of an actor are captured by stereo color video cameras, and color region which has the same color of the marker's color in the captured images is separated from the other colors by finding dominant wavelength of colors. Color data in RGB (red, green, blue) color space is converted into CIE (Commission Internationale del'Eclairage) color space for the purpose of calculating wavelength. The dominant wavelength is selected from histogram of the neighbor wavelengths. The motion of the character in the cyber space is controlled by a program using the distance information of the moving markers.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.837-846
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• 2012

This paper presents a watermarking scheme based on the perspective distance for the secure mash-up service. The proposed scheme embeds the watermark of the location information of satellite image and the user information using edge color histogram, which is dissimilar to general digital image. Therefore, this scheme can trace the illegal distributor and can protect private information of user through the watermarking scheme that is adaptive to satellite image. Experimental results verified that our scheme has the invisibility and also the robustness against geometric attacks of rotation and translation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.408-413
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• 2005

This paper presents a technique which extracts a moving object from omni-directional images and estimates a real coordinates of the moving object using 3D parabolic coordinate transformation. To process real-time, a moving object was extracted by proposed Hue histogram Matching Algorithms. We demonstrate our proposed technique could extract a moving object strongly without effects of light changing and estimate approximation values of real coordinates with theoretical and experimental arguments.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.125-133
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• 2024

In this paper, we propose a volume measurement method for an object based on depth image. The object volume is measured by calculating the object height and width in actual units through the depth image. The object area is detected through differences between the captured and background depth images. The volume of the 2×2 pixel area, formed by four adjacent pixels using the depth information associated with each pixel, is measured. The object volume is measured as the sum of the volumes for whole 2×2 areas in the object area. In simulation results, the average measurement error for the object volume is 2.1% when the distance from the camera is 60cm.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.691-693
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• 2004

센서 네트워크의 응용 분야 중에서 센서가 밀집되게 분포 되어야 하는 경우 적절한 개수의 노드만 활성화시켜 이 노드들 만으로 전송 경로를 구성하여 센서가 수집한 데이터를 데이터 수집 노드에 전달되도록 한다. 휴지 상태에 있는 노드를 활성화하는 기존의 모델들은 활성 노드의 개수와 전송 손실률을 이용하거나 지리 정보를 이용하여 센서 네트워크 토폴로지를 구성하였다. 이 논문에서는 활성 노드 간의 거리 정보를 이용하여 센서 네트워크 토폴로지를 구성하는 방법을 제안한다 이 방법을 사용한 결과 지역적으로 활성 노드가 균일하게 분포되었으며 센서 밀집도가 높을수록 더 좋은 에너지 효율을 얻을 수 있었다.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.51-58
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• 2009

In this paper, a system which uses Bluetooth and Zigbee wireless communication and mobile device is designed. The temperature within vehicle and the distance betweeen the vehicle and the obstacle is measured by ultrasonic sensor system. The measured data is sent to the mobile PDA and displayed to assist safe driving.