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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 5, Issue 6 - Dec 2002
Volume 5, Issue 5 - Oct 2002
Volume 5, Issue 4 - Aug 2002
Volume 5, Issue 3 - Jun 2002
Volume 5, Issue 2 - Apr 2002
Volume 5, Issue 1 - Feb 2002
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Management of the Structure Information of HyTime Documents using Object-Oriented Database
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 351~360
HyTime(Hypermedia/Time-based Structuring Language), an international standard language to describe hypermedia electronic documents, is used to support the synchronization between various multimedia data for hypermedia applications. To manage the HyTime documents efficiently for shared environment, the logical structure information of them should be managed by database in a systematic way. In this Paper, we design a meta-database schema of HyTime DTDs(Document Type Definition) which define the logical structure of hypermedia documents and show how to manage the meta-database schema for storing the HyTime DTDs in the object-oriented database.
A New Spatial Indexing Method for Level-Of-Detailed Data
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 361~371
An efficient access technique is one of the most Important requirements in GIS. Using level -of-detailed data, we can access spatial data efficiently, because of no access to the fully detailed spatial data. Previous spatial access methods do not access data with level of detail efficiently. To solve it, a few spatial access methods for spatial data with level of detail, are known. However these methods support only a few kinds of data with level of detail, i.e, data through selection and simplification operations. For the effects, we propose a new spatial indexing method supporting fast searching in all kinds of data with level of detail. In the proposed method, the collection of indexes in its own level are integrated into a single index structure. Experimental results show that our method offers both no data redundancy and high search performance.
Design and Implementation of an Efficient Buffer Replacement Method for Real-time Multimedia Databases Environments
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 372~385
In this paper, we propose an efficient buffer replacement method for the real-time multimedia data. The proposed method has multi level priority to consider the real-time characteristics. Each priority level is divided into a cold data set that is likely to be referenced for the first time and a hot data set that is likely to be re-referenced. An operation to select the victim data is sequentially executed from the cold set with the minimum priority level to the hot set with the maximum Priority level. It is chosen only at the lower level than or equal to the priority of the transaction that requests a buffer allocation. In the cold set, our method selects a media that has the maximum size in the level for a target of victim first of all. And in the hot set, our method selects a medium that has the maximum interval of the reference first of all. Since it maintains many popular media in the limited buffer space, the buffer hit ratio is increased. It also manages many service requests. As a result, our method improves the overall performance of the system. We compare the proposed method with the Priority-Hints method in terms of the buffer hit ratio and the deadline missing ratio of transactions. It is shown through the performance evaluation that our method outperforms the existing methods.
Reduction of Blocking Effect using a Rational Open Uniform B-Spline Curve
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 386~392
In this paper, we propose a novel blocking effect reduction method based on a rational B-spline. The blocking effect results from independent coding of each image block and becomes highly visible especially coded at very low bit rates. The proposed approach adopts a rational open uniform B-spline curve that used to produce a smooth curve through a set of control points. The pixels on the block boundary are treated as control points, and the weight values, which decide the shape of curve, are determined differentially by considering the distance the position of the pixels and that of the block boundary. The simulation results show that the proposed method has excellent performance for all pattern of the blocking effect with less computational complexity.
A Two-Stage Bit Allocation Algorithm for MPEG-1 Audio Coding
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 393~398
The conventional bit allocation scheme for MPEG-1 audio encoding searches the subband with minimum MNR(mask-to-noise ratio) repetitively until its operation is completed, which occupies most of its total computational complexity. In this paper, as a computationally efficient approximation of it, we propose a new bit allocation scheme with a simple subband search and compare it with the existing schemes in terms of the computational complexity and sound quality. For the performance comparison, we used the pop music signal contained in SQAM(sound quality assess material) CD from EBU. Simulation results show that the computational complexity of the proposed method is about 42% of that of the existing one in  and the sound quality difference in terms of MNR between the two schemes is within the 0.2 ㏈, for the case of using the layer II at the bit rate of 128 kbps.
Image Restoration Considering the Edge and Flat Region
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 399~404
To restore image degraded by motion blur and additive noise, it is very difficult. In conventional restoration method, regularization is usually applied to all over the image without considering the local characteristics of image. As a result, ringing artifacts appear in edge regions and the noise amplification is introduced in flat regions. To solve this problem we propose an adaptive restoration method using directional regularization operator considering edges and the regularization operator with no direction for flat regions. We verified that the proposed method showed better results in the resolution. As a result it showed visually better image and improved better ISNR further than the conventional methods.
An Objective Speech Quality Measure using Masking Effect under Digital Mobile Telephone Network Environment
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 405~414
In this paper, we propose a new objective speech quality measure using noise masking threshold for speech quality assessment of mobile telephone network environments, and verify the effectiveness of the proposed method through the experiments. For such a purpose, well known objective speech quality measures such as BSD and PSQM are first evaluated for digital mobile telephone network environments. However, these conventional methods does not have good performance under mobile networks environments compared to literary results. To be mote effective objective speech quality measure under mobile telephone environments, the proposed method employs human psychoacoustic masking effect. The DMOS, instead of MOS, is used as a subjective speech quality measure for performance evaluation. The performance comparison are carried out with speech data collected from digital mobile telephone environments. As results, the proposed measure have and average 4% higher performance, in terms of correlation, than existing objective speech quality measures such as BSD and PSQM.
Content-based Image Retrieval using Feature Extraction in Wavelet Transform Domain
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 415~425
In this paper, we present a content-based image retrieval method which is based on the feature extraction in the wavelet transform domain. In order to overcome the drawbacks of the feature vector making up methods which use the global wavelet coefficients in subbands, we utilize the energy value of wavelet coefficients, and the shape-based retrieval of objects is processed by moment which is invariant in translation, scaling, rotation of the objects The proposed methods reduce feature vector size, and make progress performance of classification retrieval which provides fast retrievals times. To offer the abilities of region-based image retrieval, we discussed the image segmentation method which can reduce the effect of an irregular light sources. The image segmentation method uses a region-merging, and candidate regions which are merged were selected by the energy values of high frequency bands in discrete wavelet transform. The region-based image retrieval is executed by using the segmented region information, and the images are retrieved by a color, texture, shape feature vector.
The Reconstructive Method for The Enhancement of Depth Resolution for Acoustic Image using the Spatial Frequency Response in NPPs' Material
Koo, Gil-mo ; Kim, Hyun ; Park, In-ho ;
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 426~433
In this paper, we have studied the images which have been reconstructed by using combination of images acquired by the variation of operating frequency. When inner images have been reconstructed, they have been superposed by the surface state effect. In this case, the images of the phase object can be enhanced by the contrast of inner images. In this experiment, there are two kinds of specimens, one is a reference block haying 1/4T, 1/2T, 3/4T side drilled holes as main run piping material 111 the steam generator in NPP(Neuclear Power Plant)s and the another is a part of a hemisphere type specimen having about 1-2㎜ distance gap. It has been shown that the two results of defect shapes have better than before in this processing and phase contrast grow about twice. And we have constructed the acoustic microscope by using a quadrature detector that enables to acquire the amplitude and phase of the reflected signal simultaneously Further more ore have studied the reconstruction method of the amplitude and phase images and the enhancement method of the defect images contrast.
Design of a Online Digital Storytelling System Making a Cartoon Sketch into a Motion Picture
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 434~440
This paper proposes a digital storytelling system that employs a method of making users simple online sketch being animated in 3D. To help users focus on their story development, our proposed system gives sketch guidelines providing 3D scene structure, and publishes final results as animated scenes with story text across time. This system is based on the web and the authoring process can also be shared with others.
An Efficient Load-Balancing Algorithm based on Bandwidth Reservation Scheme in Wireless Multimedia Networks
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 441~449
For multimedia traffics to be supported successfully in wireless network environment, it is necessary to provide Qualify-of-Service(QoS) guarantees among mobile hosts(clients). In order to guarantee the QoS, we have to keep the call blocking probability below a target value during hand-off session. However, the QoS negotiated between the client and the network may not be guaranteed due to lack of available channels for traffic of a new cell, since on service mobile clients should be able to continue their sessions. In this paper, we propose an efficient load-balancing algorithm based on the adaptive bandwidth reservation scheme for enlarging available channels in a cell. Proposed algorithm predicts the direction of clients in a cell and adjusts the amount of the channel to be reserved according to the load status of the cell. This method is used to reserve a part of bandwidths of a cell for hand-off calls to its adjacent cells and this reserved bandwidth can be used for hand-off call prior to new connection requests. If the number of free channels is also under a low threshold value, our scheme use a load-balancing algorithm with an adaptive bandwidth reservation. In order to evaluate the performance of our algorithm, we measure metrics such as the blocking probability of new calls and dropping probability of hand-off calls, and compare with those of existing schemes.
Robust Channel Estimation Method for OFDM Systems with Mobile Speed
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 450~457
Conventional channel estimation methods for OFDM system have not the robust characteristics relating to various mobile speed. To solve this drawback in conventional methods, we propose the channel estimation method for OFDM, which has a good performance and computational complexity in consideration of other methods. Proposed method uses a block frame structure within a whole channel in contrast with conventional methods such as PSAM and ESAE. This concept prevents overall performance from diverging or showing a poor one. The analytical results demonstrate the proposed method outperforms PSAM and ESAE in terms of MSE and BER performance under all Rayleigh fading environment. Considering the simulation performance and computational complexity, proposed method shows better characteristics than conventional methods for OFDM and has not an error floor even in a severe Rayleigh fading environment.
Mesh Simplification for Preservation of Characteristic Features using Surface Orientation
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 458~467
There has been proposed many simplification algorithms for effectively decreasing large-volumed polygonal surface data. These algorithms apply their own cost function for collapse to one of fundamental simplification unit, such as vertex, edge and triangle, and minimize the simplification error occurred in each simplification steps. Most of cost functions adopted in existing works use the error estimation method based on distance optimization. Unfortunately, it is hard to define the local characteristics of surface data using distance factor alone, which is basically scalar component. Therefore, the algorithms cannot preserve the characteristic features in surface areas with high curvature and, consequently, loss the detailed shape of original mesh in high simplification ratio. In this paper, we consider the vector component, such as surface orientation, as one of factors for cost function. The surface orientation is independent upon scalar component, distance value. This means that we can reconsider whether or not to preserve them as the amount of vector component, although they are elements with low scalar values. In addition, we develop a simplification algorithm based on half-edge collapse manner, which use the proposed cost function as the criterion for removing elements. In half-edge collapse, using one of endpoints in the edge represents a new vertex after collapse operation. The approach is memory efficient and effectively applicable to the rendering system requiring real-time transmission of large-volumed surface data.
Designing and Implementing EJB Component for Transform XML Documents based on Object Model
Journal of Korea Multimedia Society, volume 5, issue 4, 2002, Pages 468~476
Nowadays for reliable software and cost reduction there are many research works on software development based on component. One of the challenge in designing a component-based system is determining which components are required and where they fit in the overall system architecture. In this paper, we developed a EJB component for transforming RDB instances to XML documents. Accordly users can build XML applications based on relational database just by assembling this component. Consequently they can reduce time and cost for developing their XML applications.