• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2653-2663
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• 1997

The successive and parallel interference cancellation schemes are two well-known types of multi-stage interference cancellation schemes using the conventional correlator receivers as a basic building block, which has been known to significantly improve the performance of DS/CDMA system in the multiple access communication. Performance comparison between these two schemes is made strictly based on the analytical and it has been shown that the successive interference cancellation (SIC) scheme is more resistant to fading than the parallel interference cancellation (PIC) scheme. We further investigate the performance of the successive IC scheme subject to the delay constraint, which may be imposed typically on most of service applications with a real-time transmission requirement, including speech and video applications. Our analysis demonstrates that the performance may be significantly improved by the groupwise successive interference cancellation (GSIC) scheme, which can be properly optimized to meet the given delay constraint.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.47-53
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• 2012

In general, it is essential that contents are to be provided with proper bitrate according to network conditions in order to support higher quality of video streaming services over wired and wireless networks. Recently, DASH is adopted by the MPEG as the standard for HTTP based adaptive streaming technology and consists of the server and clients. The clients should parse XML files from the server and play contents after accessing the finely divided segments into various bitrates. In this paper, we designed a Smart AP(Access Point) which exists between DASH contents server and Non-DASH clients enables provide DASH services to Non-DASH clients. In addition, proposed Smart AP provides DASH service to various types of clients as maintaining the existing environment without additional development costs.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.33-37
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• 2014

This paper propose a method to sort flame regions and non-flame regions in a color image based on temperature Characteristics of flame. The traditional algorithms simply detect flame regions those are colored between yellow and red and there are lot of false detection in this method. But the colors of real flame are fallen between white and red and flame color variation over the flame. In this paper, it reduce false detection by separating colors according to temperature Characteristics of flame. The proposed method firstly finds a color model to express the temperature Characteristics of fire and then the color model is non-linearly quantized based on color values and analyzed using histogram and finally detect the candidate flame regions. The proposed method has 71.8% of matching rate and if it is compared with non-matching rate of traditional algorithms, the non-matching rate is improved by 27 times than others.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.38-41
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• 2014

Due to the diversity of device performances and the possibility of providing multimedia service through many networks, media consumption environment has been changed in various ways. In recent, mobile services and broadcasting services started to provided through IP network. According to this flow changes, there was great demand for various multimedia services through heterogenous networks. To solve this problem, MMT was suggested as a standard of multimedia transport which replaces MPEG-2 TS(Transport Stream) which is used for HD(High Definition) transport. MMT can be provided various broadcasting based on IP through terrestrial, satellite, cable broadcasting networks, and also deliver multimedia through many networks at the same time. MMT was risen as a method of servicing UHD broadcasting. In this paper, we present an implementation of service architecture for hierarchical UHD broadcasting over heterogenous networks using MMT.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.6-11
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• 2013

Recently sports science is various attempts to improve the athletes' performances. Above all they collect a results for the data and analyze the movement of the players after the game. Based on this, they are utilized to complement the vulnerability and how to improve. However, this way is not able to understand the movement a player and the flow of the game in real time. Because they are analyzed to match results based on the data. Therefore it is possible to managed for performance enhancement used to IT technology during the game in real-time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1783-1791
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• 2010

Mobile WiMAX system provides broadband wireless access with a variety of services such as voice, video and data communications and providing QoS for each of these services become an important issue. In Mobile WiMAX system, it is important to allocate resources appropriately in order to support the efficient utilization of resources among various real-time and non real-time services. Although many packet scheduling schemes for real-time services in OFDMA system have been proposed, it need to be modified to apply to Mobile WiMAX system. Since Mobile WiMAX supports five types of service classes, QoS constraints of each class should be taken into consideration. In this paper, we propose an efficient packet scheduling scheme to support various services by considering the QoS constraints of each class.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.855-869
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• 1997

In this paper, we proposed two kids of dynamic priority control mechanisms controlling the cell service ratio in order to improve the QOS(Quality of Service). We also analyse theoretically the characteristics of cell loss probability and mean cell delay time by applying the proposed priority control mechanisms to ATM switch with output buffer. The proposed priority control mechanisms have the same principles of storing cells into buffer but the different principles of serving cells from buffer. The one is the control mechanism controlling the cell service ratio according to the relative cell occupancy ratio of buffer, the other is the control mechanism controlling the cell service ratio according to both the relative cell occupancy ratio of buffer and the average arrival rate. The two service classes of our concern are the delay sensitive class and the loss sensitive class. The analytical results show that the proposed control mechanisms are able to improve the QOS, the characteristics of cell loss probability and mean cell delay time, by selecting properly the relative cell occupancy ratio of buffer and the average arrival rate. conventional DLB algorithm does not support synchronous cells, but the proposed algorithm gives higher priority to synchronous cells. To reduce synchronous cell loss rate, the synchronous cell detector is used in the proposed algorithm. Synchronous cell detector detects synchronous cells, and passes them cells to the 2nd Leaky-Bucket. So it is similar to give higher priority to synchronous cells. In this paper, the proposed algorithm used audio/video traffic modeled by On/Off and Two-state MMPP, and simulated by SLAM II package. As simulation results, the proposed algorithm gets lower synchronous cell loss rate than the conventional DLB algorithms. The improved DLB algorithm for multimedia synchronization can be extended to any other cells which require higher priority.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1925-1938
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• 2001

In this paper, a new block-matching algorithm for standard video encoder is presented. The slice competition method is proposed as a new scheme, as opposed to a coarse-to-fine approach. The order of calculating the SAD(Sum of Absolute Difference) to fad the best matching block is changed from a raster order to a dispersed one. Based on this scheme, the increasing SAD curve during its calculation is more linear than that of other curves. Then, the candidates of low probability can be removed in the early stage of calculation. And new MV prediction technique with an adaptive search range scheme also assists the proposed block-matching algorithm. As a result, an average of 13% improvement in computational power is recorded by only the proposed MV prediction technique. Synthetically, the computational power is reduced by 3977∼77% than that of the conventional BMAs. The average MAD is always low in various sequences. The results are also very close to the MAD of the full search block-matching algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.454-463
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• 2010

After the efficiency of H.264 video compression has been announced, it replaced MPEG-2 standard in several applications. So transcoding methods of MPEG-2 to H.264 have been studying because there are variety devices and contents followed by MPEG-2. Although H.264 supported various service such as IPTV, DMB, digital broadcasting etc, but users using MPEG-2 devices cannot accessible to them. This paper propose H.264 to MPEG-2 transcoding for users of MPEG-2 devices without displacement H.264. The proposed method predicted a motion vector for MPEG-2 encoder after it extracted from motion vectors of variable blocks in H.264 to improve processing time. Also it predicted a optimal motion vector using modified boundary matching algorithm after grasped a special character for boundary and background of object. The experimental results from proposed method show a considerable reduction in processing time, as much as 68% averagely, with a small objective quality reduction in PSNR.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.80-91
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• 2002

A general goal of the AT%(Asynchronous Transfer Mode) network is to support connect across various network. On ATM networks, ABR services are provided using the remained ban after allocation CBR and VBR traffic. Realtime services such as transmitting audio or video data may be provided using CBR ado VBR which have a constrained transmission delay, but in these cases, the communications bandwidth may be wasted. In this paper a simulation has been performed to compare and evaluate the performance between the ERICA(Explicit Rate Indicate Avoidance) and EPRCA(Enhanced Proportional Rate Control Algorithm) switches which use Explicit Rate switch algorithm for ABR switch. The variation of the ACR at the source end system, the queue length, the utilization rate of the link bandwidth and the share fairness at the transient and steady states are used as the evaluation criteria for the simulation. As a result of simulation, ERICA algorithm switch was ten times long compared to ERPCA switch to achieve assigned fair share. so EPRCA switch is superior to ERICA about load response. For Fair share and stability, ERICA switch is excellent to EPRCA switch.