• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.867-870
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• 1998

Video data is usually stored in a compressed format in order to reduce the storage space. For efficient browsing, searching, and retrieval of compressed video sequences, size-reduced images (or DC images which are formed with block DC coefficients) are generally preferred to avoid unnecessary computational complexity. In this paper, we propose a DC image extraction scheme appropriate for scene analysis and efficient browsing of compressed video sequences. The proposed algorithm utilizes predicted low frequency AC coefficients to achieve better approximation and to reduce the error drift. Due to the AC prediction based on a quadratic surface model, the proposed scheme requires no additional memory compared with the previous zero-order or first-order approximation scheme. Simulation results show that the proposed scheme achieves better subjective and objective quality with minor additional operations.

• Journal of Information Technology Applications and Management
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• v.17 no.1
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• pp.107-125
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• 2010

The purpose of this research is to identify the critical factors influencing on the continuous use of video telephony service for mobile devices. An empirical analysis has been performed by using service quality, brand image, price, fun as influencing factors, and satisfaction and commitment as mediating factors. The partial least squares(PLS) methodology with 228 questionnaires has been conducted. The results indicated that brand image, price, and fun were mediated by satisfaction and commitment to have a statistically significant influence on continuous use of video telephony service. Service quality showed a significant effect on continuous use mediated by satisfaction while it did not show any influence through commitment. Based on the results, companies in the communication service industry should consider and focus on the improved brand image, appropriate fees, and individual preferences for fun for the successful marketing activities, and should also maintain amicable relations with their customers.

• The KIPS Transactions:PartC
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• v.8C no.2
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• pp.164-172
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• 2001

최근 인터넷의 확산과 더불어 디지털 비디오 라이브러리(DVL : Digital Video Library) 서비스에 대한 관심이 고조되고 있다. 그러나 현재의 통신망 대역폭과 스위칭 환경 하에서는 종단간 QoS 보장하는데 많은 제약사항이 존재한다. 따라서 본 논문에서는 비디오 스트림 처리를 효율적으로 수행하여, 지연-처리율 특성을 만족할 수 있는 스트림 스위칭 구조를 제안하고 이에 대한 성능을 분석하였다. 제안된 ATM-기반 스트림 스위치는 각각 다중화되는 CBR(Constant Bit Rate) 및 VBR(Variable Bit Rate) 스트림의 QoS(Quality of Service)를 보장해야만 한다. 성능분석 결과는 제안된 스위치의 처리율이 r=4일 때 약 0.996의 값을 보였으며, 지연시간도 부하가 0.7 이하일 때 2미만으로 특정되었다. 이 결과는 제안된 구조가 적당한 입력 스트림의 그룹핑을 통하여 비디오 응용을 위한 처리율 및 지연 요구사항 QoS를 보장할 수 있음을 보여준다.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.267-270
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• 2003

The DMB recently standardized in Korea is a Eureka-147 DAB(Digital Audio Broadcasting)-based standard which is able to provide multimedia services including moving pictures, still images, text and etc. That has the structure to add the MPEG media codec and the MPEG system, namely, video-multiplexer to the DAB system. In this paper, we analysis the video-multiplexer of the DMB standard and propose a new multiplexer, namely. M4GM(MPEG-4 General Mux) included in the DMB vido-multiplexer for the performance improvement with respect to the transmission efficiency and the expansible functions. In addition, we simulate the two video-multiplexers and then compare and estimate their performance entirely.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.143-146
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• 2011

This paper presents human perception-based video coding method using an online learning framework. In this work, we analyze the relationship between human attention regions and video quality, and also consider human memory. We classify the motion patterns based on the analysis. Then, we devise a motion pattern classification method using Hedge algorithm. Along with the motion patterns, we smooth out the specific regions or sharpen details of the regions using the regional priorities. The preprocessed sequences are applied to the video codec. The performance is excellent on the overall quality as well as the regional quality.

• IE interfaces
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• v.9 no.3
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• pp.202-213
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• 1996

Video-on-demand is an interactive service that provides programs (movie, home shopping, etc.) to users connected to a network. This service will require high bandwidth network and video servers with a large amount of storage capacity. From the viewpoint of system analysis, there are optimization problems to be solved. In this paper, we present a dynamic programming method for allocating the storage for programs being served in a multi-level video-on-demand network. In the optimization of the network resource, we consider the three kinds of costs: installation cost for video servers, program storage cost, and transmission (or communication) cost. The factors related to the costs are investigated. An example is shown to illustrate the proposed method.

• Journal of Information Science Theory and Practice
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• v.4 no.4
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• pp.4-15
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• 2016

Information needs of users have been examined both generally and as they pertain to particular types and formats of information. Barriers to information have also been investigated, including those which are situational and also across certain domains and socioeconomic contexts. Unified studies concerning both information needs and barriers are needed. Both are likely always present in any given interactive search situation; further, users' attempts to satisfy their own individualized information needs will likely encounter barriers of some sort. The present study employed a survey method to collect users' perceptions of video information needs and barriers as part of recent video search situations. Findings from this analysis establish a unified framework, based on the themes emerging directly from the responses of users, and present the suitability and benefit for informing future designs and evaluations of user-centered interactive retrieval tools.

• International journal of advanced smart convergence
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• v.9 no.4
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• pp.120-123
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• 2020

The surveillance system to prevent crime and accidents in advance has become a necessity, not an option in real life. Not only public institutions but also individuals are installing surveillance cameras to protect their property and privacy. However, since the installed surveillance camera cannot be monitored for 24 hours, the focus is on the technology that tracks the video after an accident occurs rather than prevention. In this paper, we propose a system model that monitors abnormal behaviors that may cause crimes through real-time video, and when a specific behavior occurs, the surveillance system automatically detects it and responds immediately through an alarm. We are a model that analyzes real-time images from surveillance cameras and uses I3D models from analysis servers to analyze abnormal behavior and deliver notifications to web servers and then to clients. If the system is implemented with the proposed model, immediate response can be expected when a crime occurs.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.148-150
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• 2020

최근 VVC(Versatile Video Coding) 표준 완료 이후 JVET(Joint Video Experts Team)은 인공신경망 기반의 비디오 부호화를 위한 AhG(Ad-hoc Group) 구성하고 인공지능을 이용한 비디오 압축 기술들을 검증하고 있으며, MPEG(Moving Picture Experts Group)에서는 DNNVC(Deep Neural Network based Video Coding) 활동을 통해 딥러닝 기반의 차세대 비디오 부호화 표준 기술을 탐색하고 있다. 본 논문은 VVC 에 채택된 신경망 기반의 기술인 MIP(Matrix Weighted Intra Prediction)를 참조하여, MIP 모델의 학습에서 손실함수가 예측 성능에 미치는 영향을 분석한다. 즉, 예측의 왜곡(MSE)만을 고려한 경우와 예측오차의 부호화 비용도 함께 반영한 손실함수를 비교한다. 실험을 위해 HEVC(High Efficiency Video Coding) 화면내 예측 대비 평균적인 PSNR 향상 정도를 나타내는 성능 지표(��PSNR)를 정의한다. 실험결과 예측오차의 부호화 특성을 반영하는 손실함수를 이용한 학습이 MSE 만 고려한 학습 대비 ��PSNR 기준 평균 0.4dB 향상됨을 보였다.

• Science of Emotion and Sensibility
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• v.23 no.4
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• pp.41-60
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• 2020

In this study, we examined the effects of video game play on a variety of areas of mental well-being, such as aggressive behavior, aggressive cognition, prosocial behavior, prosocial attitude, antisocial behavior, antisocial attitude, positive affect, and negative affect. We conducted a multivariate meta-analysis on 22 studies (k= 54, N = 8,031) published between January 2008 and October 2019. The results of the meta-analysis indicate that exposure to violent video games significantly increased aggressive cognition and negative affect only in true experimental studies, but their influences were small. Furthermore, the exposure to violent video games did not increase aggressive behavior and negative affect across all the research designs (true experimental, quasi-experimental, and correlational). Moderator analyses revealed that the effects of exposure to violent video games were much larger for younger adults than for children and greater in male-biased studies than in gender-balanced ones. Additionally, studies using better methodologies were less likely to produce negative effects. These findings suggest that the effects of exposure to violent video games on aggression were not as severe as popular opinion holds, and the effects were heavily modulated by the age and gender ratio of the participants, and methodological quality of the studies.