• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.28-36
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• 2013

Motion-compensated frame interpolation (MCFI) techniques in video signal processing have many application areas. Frame rate up-conversion (FRUC) or distributed video coding (DVC) technique needs an effective MCFI algorithm. For these applications, it is necessary to develop an effective post-processing technique to improve visual qualities or to reduce virtual channel noises, resulting in the reduced channel bit rate. This paper proposes a reliability evaluation method based on spatio-temporal characteristics for motion-compensated interpolated blocks. The proposed algorithm investigates the temporal matching characteristics for current frame and then is designed in such a way that it can measure temporal characteristics as well as the spatial ones. Through computer simulations, it is shown that the proposed method outperforms the conventional temporal matching method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.49-55
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• 2019

An open office or a shared office is emerging as the emphasis on the collaborative and communicative work environments is increasing. In the past, the user maintained the space, but the maintenance of indoor space became difficult because there is no fixed user. Indoor space information can be collected using the ICBM framework system. The facility management can achieve this with data. Therefore, this study proposed a framework based on ICBM (Internet of Things, Cloud, Big Data, and Mobile) for verifying the possibility of a smart facility management system for indoor space. IoT (Internet of Things) technology was used to measure the indoor temperature, humidity, occupancy, and brightness continuously, and provided the data to Web API via WiFi. Data acquired automatically via IoT, existing maintenance data, and spatial information were integrated through the Cloud. Big data collected by sensors were processed as meaningful spatial information for maintenance. Indoor space information and maintenance information can be delivered to the manager through the mobile. Based on the collected data, room occupancy recognition is limited due to a range of ultrasonic wave sensors. On the other hand, brightness represents the space conditions. The difference between lighting on/off, weekday and weekend can be shown. The temperature data and the relative humidity data were collected steadily to evaluate the comfort.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.535-546
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• 2011

In this paper, semi-rigid elasto-plastic post-buckling analysis of a space frame was performed using various explicit arc-length methods. Various explicit arc-length methodsand a large-deformation and small-strain elasto-plastic 3D space frame element with semi-rigid connections and plastic hinges were developed. This element can be appliedto both explicit and implicit numerical algorithms. In this study, the Dynamic Relaxation method was adopted in the predictor and corrector processesto formulate an explicit arc-length algorithm. The developed "explicit-predictor" or "explicit-corrector" were used in the elasto-plastic post-buckling analysis. The Eulerian equations for a beam-column with finite rotation, which considers the bowing effects, were adopted for the elastic system and extended to theinelastic system with a plastic hinge concept. The derived tangent stiffness matrix was asymmetrical due to the finite rotation. The joint connection elements were introduced for semi-rigidity using a static condensation technique. Semi-rigid elasto-plastic post-buckling analyses were carried out to demonstrate the potential of the developed explicit arc-length method and advanced space frame element in terms of accuracy and efficiency.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.561-571
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• 2020

Seven techniques widely used in the geodetic transformations have been reviewed and compared to figure out their theoretical characteristics. A series of numerical tests were performed about four data sets. This was followed by result analyses in terms of transformation residuals and accuracies together with some hypothesis testings based on the student-t distribution to confirm the statistical significance of the techniques. In the case of the transformation between the geodetic frames implemented in the same system, no statistical significance was revealed in the results of the 3D transformation techniques, even if the testing area becomes large as the Asia-Oceania continent. Among the 2D transformations, it was possible for the NTv2 grid modeling technique to deliver improved transformation accuracy. Finally, it was possible from the results analyzed in this study to propose the Helmert transformation to geodetic control points and the NTv2 technique to the 2D spatial data transformation of the geodetic systems.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.47-53
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• 2002

In this paper, we proposed a content-based video search method using the eigen value of key frame and intensity component. We divided the video stream into shot units to extract key frame representing each shot, and get the intensity distribution of the shot from the database generated by using ECA(Eigen Component Analysis). The generated codebook, their index value for each key frame, and the intensity values were used for database. The query image is utilized to find video stream that has the most similar frame by using the euclidean distance measure among the codewords in the codebook. The experimental results showed that the proposed algorithm is superior to any other methols in the search outcome since it makes use of eigen value and intensity elements, and reduces the processing time etc.

• Journal of Korea Game Society
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• v.9 no.4
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• pp.89-96
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• 2009

In general, the size of volume data is large since it has logical 3D structure so it takes long time to manipulate. Much work has been done to improve processing speed of volume data. In this paper, we propose a interlaced scanning volume rendering that reduce computation time by using temporal coherence with minimum loss of image quality. It renders a current frame by reusing information of previous frame. Conventional volume raycasting renders each frame by casting rays on every pixels. On the other hand, our methods divided an image into n-pixel blocks, then it casts a ray on a pixel of a block per each frames. Consequently, it generates an image by accumulating pixel values of previous n frames. The quality of rendered image of our method is better than that of simple screen space subsampling method since it uses afterimage effect of human cognitive system, and it is n-times faster that the previous one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2071-2078
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• 2009

The first frame is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the intial QP (Quantization Parameter) for the first frame affects the first frame as well as the following frames. Traditionally, the initial QP is determined among four constant values only depending on the bpp. In the case of low bit rate video coding, the initial QP value is fixed to 35 regardless of the output bandwidth. Although this initialization scheme is simple, yet it is not accurate enough. An accurate intial QP prediction scheme should not only depends on bpp but also on the complexity of the video sequence and the output bandwidth. In the proposed scheme, we use a linear model because there is a linear inverse proportional relationship between the output bandwidth and the optimal intial QP. Model parameters of the model are determined depending on the spatial complexity of the first frame. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JM algorithm.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.496-499
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• 2009

본 논문은 기하학적 비선형성을 가진 보존적 단일 하중 매개변수의 탄성 상태 공간구조의 분기이론에 관한 수치 해석적 기본 방법 및 경로 추적, pin-pointing, 경로 전환을 기술하고 있다. 비선형 탄성 불안정 상태는 극한점과 분기점으로 분류될 수 있으며, 평형경로상의 평형점의 계산 및 평형경로상의 특이점을 찾기 위한 pin-pointing 반복계산을 수행하는 일반적인 비선형 수치해석법으로 극한점을 계산할 수 있다. 그러나 분기좌굴 해석을 위해서는 좌굴 후 분기경로의 추적을 위한 분기경로 전환 알고리즘이 추가적으로 필요하다. 본문에서는 에너지이론에 기초한 일반 탄성안정이론을 소개하고, 평형경로 추적, 분기 좌굴점을 찾기 위한 직접법과 분기경로 전환에 관한 이론을 전개한다. 분기좌굴 해석예제로 트러스로 이루어진 스타돔, 핀지지의 평면아치, 평면프레임, 3차원 공간프레임의 분기좌굴 해석을 수행하여 본문에서 제시한 수치해석법의 정확성 및 실용성을 검증한다.

• Electronics and Telecommunications Trends
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• v.34 no.4
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• pp.1-14
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• 2019

Recent trends in deep reinforcement learning (DRL) have revealed the considerable improvements to DRL algorithms in terms of performance, learning stability, and computational efficiency. DRL also enables the scenarios that it covers (e.g., partial observability; cooperation, competition, coexistence, and communications among multiple agents; multi-task; decentralized intelligence) to be vastly expanded. These features have cultivated multi-agent reinforcement learning research. DRL is also expanding its applications from robotics to natural language processing and computer vision into a wide array of fields such as finance, healthcare, chemistry, and even art. In this report, we briefly summarize various DRL techniques and research directions.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.661-675
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• 2009

The carelessly and illegally copied contents are raising serious social problem as internet and multimedia technologies are advancing. Therefore, development of video copy detection system must be settled without delay. In this paper, we propose the hierarchical video copy detection method that estimates similarity using statistical characteristics between original video and manipulated(transformed) copy video. We rank according to luminance value of video to be robust to spacial transformation, and choose similar videos categorized as candidate segments in huge amount of database to reduce processing time and complexity. The copy videos generally insert black area in the edge of the image, so we remove rig black area and decide copy or not by using statistical characteristics of original video and copied video with center part of frame that contains important information of video. Experiment results show that the proposed method has similar keyframe accuracy to reference method, but we use less memory to save feature information than reference's, because the number of keyframes is less 61% than that of reference's. Also, the proposed method detects if the video is copied or not efficiently despite expansive spatial transformations such as blurring, contrast change, zoom in, zoom out, aspect ratio change, and caption insertion.