• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.583-591
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• 2000

Caching mechanisms have been studied extensively to buffer the speed gap of hierarchical storages in the context of cache memory, paging system, and buffer management system. As the wide-area distributed environments such as the WWW extend broadly, caching of remote objects becomes more and more important. In the wide-area distributed environments, the cost and the benefit of caching an object is not uniform due to the location of the object; which should be considered in the cache replacement algorithms. For online operation, the time complexity of the replacement algorithm should not be excessive. To date, most replacement algorithms for the wide-area distributed environments do not meet both the non-uniformity of objects and the time complexity constraint. This paper proposes a replacement algorithm which considers the non-uniformity of objects properly; it also allows for an efficient implementation. Trace-driven simulations show that proposed algorithm outperforms existing replacement algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.4
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• pp.617-623
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• 2018

In this paper, we propose a novel seamless video composition method based on shape matching and Poisson equation. Video composition method consists of video segmentation process and video blending process. In the video segmentation process, the user first sets a trimap for the first frame, and then performs a grab-cut algorithm. Next, considering that the performance of video segmentation may be reduced if the color, brightness and texture of the object and the background are similar, the object region segmented in the current frame is corrected through shape matching between the objects of the current frame and the previous frame. In the video blending process, the object of source video and the background of target video are blended seamlessly using Poisson equation, and the object is located according to the movement path set by the user. Simulation results show that the proposed method has better performance not only in the naturalness of the composite video but also in computational time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.231-237
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• 2020

In this paper, we provide an efficient hybrid video blending scheme to improve the naturalness of composite video in Poisson equation-based composite methods. In image blending process, various blending methods are used depending on the purpose of image composition. The hybrid blending method proposed in this paper has the characteristics that there is no seam in the composite video and the color distortion of the object is reduced by properly utilizing the advantages of Poisson blending and alpha blending. First, after blending the source object by the Poisson blending method, the color difference between the blended object and the original object is compared. If the color difference is equal to or greater than the threshold value, the object of source video is alpha blended and is added together with the Poisson blended object. Simulation results show that the proposed method has not only better naturalness than Poisson blending and alpha blending, but also requires a relatively small amount of computation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.275-276
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• 2014

일반적으로 래스터 그래픽스 기반으로 구성된 사용자 인터페이스는 등심선을 원하는 형태로 생성 및 편집하는 저작도구 인터페이스를 제공함에 있어 그래픽 모델의 확장성과 생산성에 대한 제약으로 인해 자유로운 그래픽 표현에 많은 어려움을 나타내고 있다. 본 논문에서는 이러한 문제를 해결하기 위해 객체 지향 그래픽스 기술인 WPF 사용자 인터페이스를 통해 벡터 곡선을 독립적인 콘텐츠로 모델링하여 등심선 생성 및 편집도구에 독창적이고 유연한 그래픽 표현이 가능하도록 사용자 인터페이스를 제공하는 방법을 제안한다. 이를 위해 등심선의 그래픽 레이아웃은 조절점과 곡선으로 분할하여 벡터 곡선에 대한 컨테이너 요소를 제공하였고, 최종적으로 프로토 타입의 저작도구를 이용해 등심선의 모의 편집 실험을 실시하여 제안하는 방법의 우수성을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1502-1505
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• 2013

프레젠테이션을 위한 기존 방비들은 기능이 제한적이거나 또는 고비용이라는 문제점을 가지고 있다. 본 논문에서는 깊이 카메라를 이용한 손의 터치와 터치위치와 프레젠테이션 내용을 조합하여 프레젠테이션의 자유도를 높이는 방법을 제안한다. 제안 방법은 깊이 카메라로부터 스크린 영역의 깊이 값을 배경으로 설정하고, 배경과 차이나는 객체가 들어오면, 객체의 깊이 값과 배경의 깊이 값을 비교하면서 포인터를 추출한다. 모의실험 결과로부터 스크린의 상하좌우 중에 한곳에 카메라를 설치하고 프레젠테이션 페이지마다 서로 다른 위치에서 터치가 인식되고, 다양한 프레젠테이션 이벤트가 실행됨을 확인하였다.

• Journal of Korea Water Resources Association
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• v.45 no.6
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• pp.597-606
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• 2012

With the availability of multi-scale hydrologic data in public domain depending on DEM size, there is a need for a modeling framework that is capable of using these data to simulate hydrologic processes at multiple scales for different topographic and climate conditions for distributed hydrologic model. To address this need, an object-oriented approach, called Geographic and Hydrologic Information System Modeling Objects (GHISMO), is developed. Main hydrologic approaches in GHISMO are storage-release for direct runoff and SCS curve number method for infiltration part. This paper presents conceptual and structural framework of storage-release concept including its application to two watersheds will be presented.

• Journal of Broadcast Engineering
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• v.25 no.3
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• pp.362-373
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• 2020

Recently, as autonomous vehicles and intelligent CCTV are growing more interest, the efficient object detection is essential technique. The DPM(Deformable Part Models) which is basis of this paper have used a typical object system that represents highly variable objects using mixtures of deformable part for object. Although it shows high detection performance by capturing part shape and configuration of object model, but it is limited to use in real application due to the complicated algorithm. In this paper, instead of image feature pyramid that takes up a large amount of computation in one part of the detector, we propose a method to reduce the computation speed by reconstructing a new image feature pyramid that uses adaptive bilinear interpolation of feature maps obtained on a specific image scale. As a result, the detection performance for object was lowered a little by 2.82%, however, the proposed detection method improved the speed performance by 10% in comparison with original DPM.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.676-683
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• 2012

Motion estimation in video coding greatly affects implementation complexity. In this paper, a reducing method of the complexity in motion estimation is proposed by using both the depth and color cameras. We obtain object information with video sequence from distance information calculated by depth camera, then perform labeling for grouping pixels within similar distances as the same object. Three search regions (background, inside-object, boundary) are determined adaptively for each of motion estimation blocks within current and reference pictures. If a current block is the inside-object region, then motion is searched within the inside-object region of reference picture. Also if a current block is the background region, then motion is searched within the background region of reference picture. From simulation results, we can see that the proposed method compared to the full search method remains the almost same as the motion estimated difference signal and significantly reduces the searching complexity.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.670-675
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• 2012

If the region of interest (ROI) is set within the picture of image and video and the high quality is provided in ROI compared to Non ROI, then overall subjective picture quality can be increased. ROI extracted by the color camera only increases the calculation complexity and reduces the extraction accuracy. In this paper, we use depth camera to set the ROI and calculate the object distance from camera, then propose a method that the different picture quality is controlled by depending on the distance of an object. That is, we apply a high quantization step size to the far object, but relatively a low quantization step size to the close object, so better picture quality can be provided. Simulation results show that applying the differential quantization step size to the distance of objects by the proposed method can improve the subjective picture quality.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.11-20
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• 2015

In this paper, we develop an intelligent mobile surveillance system based on binary CDMA for the unmanned automatic tracking and surveillance. That is, we implement a intelligent surveillance system using the binary CDMA wireless communication technology which is applied the merit of CDMA and TDMA on it complexly. This system is able to monitor the site of the accident on network in real time and process the various situations by implementing the security surveillance system. This system pursues an object by the 360-degree using camera, expands image using a PTZ(Pan/Tilt/Zoom) camera zooming function, identifies the mobile objects image within a screen and transfers the identified image to the remote site. Finally, we show the efficiency of the implemented system through the simulation of the controlled situations, such as tracking coverage on objects, object expansion, object detection number, monitoring the remote transferred image, number of frame per second by the image output signal etc..