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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korea Multimedia Society
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Korea Multimedia Society
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Volume & Issues
Volume 9, Issue 12 - Dec 2006
Volume 9, Issue 11 - Nov 2006
Volume 9, Issue 10 - Oct 2006
Volume 9, Issue 9 - Sep 2006
Volume 9, Issue 8 - Aug 2006
Volume 9, Issue 7 - Jul 2006
Volume 9, Issue 6 - Jun 2006
Volume 9, Issue 5 - May 2006
Volume 9, Issue 4 - Apr 2006
Volume 9, Issue 3 - Mar 2006
Volume 9, Issue 2 - Feb 2006
Volume 9, Issue 1 - Jan 2006
Selecting the target year
Uncertain Region Based User-Assisted Segmentation Technique for Object-Based Video Editing System
Yu Hong-Yeon ; Hong Sung-Hoon ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 529~541
In this paper, we propose a semi-automatic segmentation method which can be used to generate video object plane (VOP) for object based coding scheme and multimedia authoring environment. Semi-automatic segmentation can be considered as a user-assisted segmentation technique. A user can initially mark objects of interest around the object boundaries and then the selected objects are continuously separated from the un selected areas through time evolution in the image sequences. The proposed segmentation method consists of two processing steps: partially manual intra-frame segmentation and fully automatic inter-frame segmentation. The intra-frame segmentation incorporates user-assistance to define the meaningful complete visual object of interest to be segmentation and decides precise object boundary. The inter-frame segmentation involves boundary and region tracking to obtain temporal coherence of moving object based on the object boundary information of previous frame. The proposed method shows stable and efficient results that could be suitable for many digital video applications such as multimedia contents authoring, content based coding and indexing. Based on this result, we have developed objects based video editing system with several convenient editing functions.
Design of Wavelet-Based 3D Comb Filter for Composite Video Decoder
Kim Nam-Sub ; Cho Won-Kyung ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 542~553
Because Y and C signals in a composite video signal are piled one on another in the same frequency, it is impossible to separate them completely. Therefore, it is necessary to develop efficient separation technique in order to minimize degradation of video quality. In this paper, we propose wavelet-based 3D comb filter algorithm and architecture for separating Y and C signals from a composite video signal. The proposed algorithm uses wavelet transform and thresholding of compared lines for acquiring the maximum video quality. Simulation results show that the proposed algorithm has better image quality and better PSNR than previous algorithms. For real application of the proposed algorithm, we developed a hardware architecture and the architecture was implemented by using VHDL. Finally, a VLSI layout of the proposed architecture was generated by using 0.25 micrometer CMOS process.
Faster Collision Response for Rigid Articulated Bodies by Reformulating Linear Equations
Jeong Dae-Hyun ; Lee Joong-Ha ; Kim Eun-Ju ; Ryu Kwan-Woo ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 554~563
We present a linear-time algorithm for treating collision response of articulated rigid bodies in physically based modeling. By utilizing the topology of articulated rigid bodies and the property of linear equations, our method can solve in linear time the system of linear equations that is crucial for treating collision response. We also present several new joint condition equations for articulated rigid bodies composed of various joints.
Improvement of Content-based Image Retrieval by Considering Image Editing Effect
Kang Seok-Jun ; Bae Tae-Meon ; Kim Ki-Hyun ; Han Seung-Wan ; Jeong Chi-Yoon ; Nam Tae-Yong ; Ro Yong-Man ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 564~575
With the rapid increase of the number of multimedia contents, people consume a lot of multimedia contents through various distribution channels. Content-based image retrieval uses visual features that represent the contents of images. And users can retrieve or filter images based on the contents of the images using the features. But, the editing of the multimedia contents distorts the original visual features of the multimedia contents, thereby the performance of content-based image retrieval system could be lowered. In this paper, we describe the image editing effects that lower the performance of the retrieval system and propose algorithms that can remove the image editing effect and improve content-based image retrieval system.
Analysis of Uniqueness and Robustness Properties of Ordinal Signature for Video Matching
Jeong Kwang-Min ; Kim Jeong-Yeop ; Hyun Ki-Ho ; Ha Yeong-Ho ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 576~584
Content-based video matching is measuring a similarity of video signature compared to the original clip and copies of media. Specially, it is very important to match the exact frame position, but it depends on frame rate, noise condition and compression format of video. Ordinal signature shows good performance than other video signatures under normal condition but the previous didn't try to find the uniqueness and robustness. Hua et al. performed a uniqueness test under compressed in different formats or frame size. However, they used other compression format image instead of noise in robustness test. This paper proposes robustness test method using several noise models and analyzes the performance of robustness and uniqueness.
Lens Position Error Compensated Fast Auto-focus Algorithm in Mobile Phone Camera Using VCM
Han Chan-Ho ; Kim Tae-Kyu ; Kwon Seong-Geun ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 585~594
Due to the size limit, the voice coil motor (VCM) is adopted in most of the mobile phone camera to control auto-focus instead of step motor. The optical system using the VCM has the property that the focus values are varying even though the same current is induced. It means that an error of the lens position was taken placed due to the characteristics of the VCM. In this paper, a algorithm was proposed to compensate the lens position error using the step size and the search count of each stage. In the proposed algorithm -7 step middle searching stage is inserted the conventional searching algorithm for the fast auto-focus searching and the final searing step size was set to +1 for the precise focus control, respectively. In the experimental results, the focus values was found more fast in the proposed algorithm than the conventional. And more the image quality by the proposed algorithm was superior to that of the conventional.
A Study of Location Based Services Using Location Data Index Techniques
Park Chang-Hee ; Kim Jang-Hyung ; Kang Jin-Suk ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 595~605
In this thesis, GPS and the electronic mapping were used to realize such a system by recognizing license plate numbers and identifying the location of objects that move at synchronous times with simulated movement in the electronic map. As well, throughout the study, a camera attached to a PDA, one of the mobile devices, automatically recognized and confirmed acquired license plate numbers from the front and back of each car. Using this mobile technique in a wireless network, searches for specific plate numbers and information about the location of the car is transmitted to a remote server. The use of such a GPS-based system allows for the measurement of topography and the effective acquisition of a car's location. The information is then transmitted to a central controlling center and stored as text to be reproduced later in the form of diagrams. Getting positional information through GPS and using image-processing with a PDA makes it possible to estimate the correct information of a car's location and to transmit the specific information of the car to a control center simultaneously, so that the center will get information such as type of the car, possibility of the defects that a car might have, and possibly to offer help with those functions. Such information can establish a mobile system that can recognize and accurately trace the location of cars.
Pro-active Routing Selection and Maintenance Algorithms for Mobile Ad Hoc Network Environments
Cho Young-Joo ; Chung Il-Yong ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 606~614
The conventional on-demand mobile ad hoc routing algorithms (DSR and AODV) initiate route discovery only after a path breaks, incurring a significant cost and time in detecting the disconnection and establishing a new route. In this theory, we investigate adding proposed pro-active route selection and maintenance to the conventional on-demand mobile ad hoc routing algorithms(DSR and AODV). The key idea is to be only considered likely to be a path break when the received packet power becomes close to the minimum critical power and to be generated the forewarning packet when the signal power of a received packet drops below a optimal threshold value. After generated the forewarning packet, the source node can initiate rout discovery in advance; potentially avoiding the disconnection altogether. Our extensive simulation study shows that the proposed advance-active route selection and maintenance algorithms outperforms the conventional on-demand routing protocol based on DSR and AODV in terms of packet delivery ratio, packet latency and overhead.
RFID Authentication System with ID Synchronization
Park Jang-Su ; Lee Im-Yeong ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 615~623
It has been estimated that 'RFID' technology would be playing an important role in the incoming ubiquitous environment. For this reason, many studies on 'RFID' have been conducted and its application has been on the increase in various fields such as finance, medicine, transportation and culture as well as in logistics distribution. However, the communication between Tag and Reader in RFID system has been conducted by wireless communication of radio frequency so that the information on identification could be eavesdropped by the third party maliciously. Such eavesdropped information could be also used as basic information in attacking others; in this regard, it could impair the privacy of its users and the users have avoided using 'RFID.' To solve theses problems, many studies are being performed to different output of tags by renewing ID. However, protocols have been devised without considering an ID Synchronization in the ID renewal process between database and tag in the existing studies. In this regard, this study has suggested a RFID Authentication Protocol while considering the ID Synchronization.
Robust Watermarking Scheme Against Geometrical Attacks Using Alignment of Image Features
Ko Yun-Ho ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 624~634
This paper presents a new watermarking scheme that is robust against geometrical attacks such as translation and rotation. The proposed method is based on the conventional PSADT(Polar Coordinates Shape Adaptive Discrete Transform) method which is an robust watermarking scheme for an arbitrarily-shaped image such as character images. The PSADT method shows perfect robustness against geometrical attack if there is no change in the shape of the image object. However, it cannot be utilized to watermark general rectangular images because of the missing alignment between the watermarked signals in the embedding and extracting side. To overcome this problem we propose a new watermarking scheme that aligns the watermark signal using the image inherent feature, especially corner. Namely the proposed method decides a consistent target region whose shape and position isn't changed by any malicious attack and then embeds the watermark in it using the PSADT method. Experimental results show the robustness of the proposed method against geometrical attacks as well as image compression.
Traffic Analysis and Modeling for Network Games
Park Hyo-Joo ; Kim Tae-Yong ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 635~648
As the advances of Internet infra structure and the support of console and mobile for network games, the industry of online game has been growing rapidly, and the online game traffic in the Internet has been increasing steadily. For design and simulation of game network, the analysis of online game traffic have to be preceded. Therefore a number of papers have been proposed for the purpose of analyzing the traffic data of network games and providing the models. We make and use GameNet Analyzer as a dedicated tool for game traffic measurement and analysis in this paper. We measure the traffic of FPS Quake 3, RTS Starcraft and MMORPG World of Warcraft (WoW), and analyze the packet size, packet IAT(inter-arrival time), data rate and packet rate according to the number of players and in-game behaviors. We also present the traffic models using measured traffic data. These analysis and models of game traffic can be used for effective network simulation, performance evaluation of game network and the design of online games.
Q-learning Using Influence Map
Sung Yun-Sick ; Cho Kyung-Eun ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 649~657
Reinforcement Learning is a computational approach to learning whereby an agent take an action which maximize the total amount of reward it receives among possible actions within current state when interacting with a uncertain environment. Q-learning, one of the most active algorithm in Reinforcement Learning, is consist of rewards which is obtained when an agent take an action. But it has the problem with mapping real world to discrete states. When state spaces are very large, Q-learning suffers from time for learning. In constant, when the state space is reduced, many state spaces map to single state space. Because an agent only learns single action within many states, an agent takes an action monotonously. In this paper, to reduce time for learning and complement simple action, we propose the Q-learning using influence map(QIM). By using influence map and adjacent state space's learning result, an agent could choose proper action within uncertain state where an agent does not learn. When this paper compares simulation results of QIM and Q-learning, we show that QIM effects as same as Q-learning even thought QIM uses 4.6% of the Q-learning's state spaces. This is because QIM learns faster than Q-learning about 2.77 times and the state spaces which is needed to learn is reduced, so the occurred problem is complemented by the influence map.
Effective Image Retrieval for the M-Learning System
Han Eun-Jung ; Park An-Jin ; Jung Kee-Chul ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 658~670
As the educational media tends to be more digitalized and individualized, the learning paradigm is dramatically changing into e-learning. Existing on-line courseware gives a learner more chances to learn when they are home with their own PCs. However, it is of little use when they are away from their digital media. Also, it is very labor-intensive to convert the original off-line contents to on-line contents. This paper proposes education mobile contents(EMC) that can supply the learners with dynamic interactions using various multimedia information by recognizing real images of off-line contents using mobile devices. Content-based image retrieval based on object shapes is used to recognize the real image, and shapes are represented by differential chain code with estimated new starting points to obtain rotation-invariant representation, which is fitted to computational resources of mobile devices with low resolution camera. Moreover we use a dynamic time warping method to recognize the object shape, which compensates scale variations of an object. The EMC can provide learners with quick and accurate on-line contents on off-line ones using mobile devices without limitations of space.
Stochastic Timed Net and Its Minimum Cycle Time Analysis
Yim Jae-Geol ; Shim Kyu-Bark ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 671~680
As a mathematical technique with which we can find the minimum duration time needed to fire all the transitions at least once and coming back to the initial marking in a timed net, the minimum cycle time method has been widely used in computer system analysis. A timed net is a modified version of a Petri net where a transition is associated with a delay time. A delay time used in a timed net is a constant even though the duration time associated with an event in the world is a stochastic number in general. In the consequence, the result of minimum cycle time analysis is not realistic. Therefore, we propose ‘Stochastic Timed Net' where a transition can be associated with a stochastic number and introduce a minimum cycle time analysis method for ‘Stochastic Timed Net’ As an example of the application of ‘Stochastic Timed Net’, we introduce a ‘Stochastic Timed Net' model of a Location Based Service Providing Multimedia System and the result of minimum cycle time analysis of it. Whereas the typical form of the result of the existing minimum cycle time analysis is 'It takes at least 10 time units', the typical form of the result of minimum cycle time analysis of a ‘Stochastic Timed Net' is in the probability form such as 'The probability of the events in which it finishes its job within 10 time units is 85%.'
Project Work and Asynchronous Voice Communication
Kim Min-Kyung ; Kim Hee-Cheol ;
Journal of Korea Multimedia Society, volume 9, issue 5, 2006, Pages 681~690
With the rapid development of network and multimedia technologies, computer mediated communication has been realized and there has been a great potential to use and research on asynchronous voice communication systems. This paper reports a case study where 6 groups(3 for documentation work, 3 for software development) of 24 people who used voice mail when carrying out their projects. The purpose of this study is to obtain an overall understanding of usability of voice mail which is a typical example of asynchronous voice communication systems, under a particular situation where project works are performed. Through the study, we came to understand general purposes of usage of voice mail, patterns of using it revealed during the project process, different ways of using it according to different types of projects, and reasons why people are currently not likely to use voice mail. The results hopefully provide systems developers with a guideline to understand the nature of voice mail from users' perspectives.