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

• Journal of Korea Game Society
• /
• v.20 no.5
• /
• pp.53-64
• /
• 2020

Supporting NNS method in KD-Tree algorithm is essential in multidimensional data applications. In this paper, we propose HD-Tree, a high-performance Lock-Free KD-Tree that supports NNS in situations where reads and writes occurs concurrently. HD-Tree reduced the number of synchronization nodes used in NNS and requires less atomic operations during Lock-Free method execution. Comparing with existing algorithms, in a multi-core system with 8 core 16 thread, HD-Tree's performance has improved up to 95% on NNS and 15% on modifying in oversubscription situation.

• Journal of Korea Multimedia Society
• /
• v.2 no.3
• /
• pp.339-346
• /
• 1999

When a multicast video conference system utilizes RTP (Real Time Protocol) and RTCP (Real Time Control Protocol), the loss rate and the synchronization of transfer in RTCP affect the scalability of the system. The random delay technique introduced to resolve the problems is so simple that leads the network to meet some congestion in synchronizing feedback information when lots of people transfer the feedback information simultaneously, which reduces the scalability of system. In this paper, we propose a new feedback control algorithm that provides priority levels with the RTCP packet, which cuts down the feedback delay and increases the scalability. The criteria of providing priority Based on the decided priority level, Agent forced the session participants to provide much more RTCP packets, positively controlled, and the possible bandwidth can be measured. The simulation on this technique decreases the delay, and the feedback messages are equally distributed on a given time period.

• Journal of Korea Multimedia Society
• /
• v.15 no.5
• /
• pp.615-623
• /
• 2012

This paper presents T-DMB AEAS (automatic emergency alerting service) receiver model considering emergency region. The proposed receiver model determines the geographical location of the terminal by analysing the received T-DMB signal and displays the AEAS messages only if the location of terminal is similar to the emergency site. First, to determine the geographical location of the terminal, we extract the TII value from the null symbol of the SC and, based on it, calculate the location of transmitter by analysing FIG 0/22 delivering the TII-related data. The proposed algorithm sets the location of transmitter as that of receiver and displays the emergency message only in the case of the similar region. The experiment was conducted in the test environment of low power T-DMB generator based on the T-DMB AEAS messages.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.6
• /
• pp.48-56
• /
• 2010

Recently, we need to dramatically speed up real-time video encoding and decoding on mobile devices because complexity of video CODEC is significantly increasing along with the demand for multimedia service of high-quality and high-definition videos by users. A variety of research is conducted for parallelism of video processing using newly developed multi-core platforms. In this paper, we propose a method of parallelism based on slice partition of video compression CODEC. We propose a novel concept of a parallel slice for parallelism and propose a new coding order to be adequate to the parallel slice which keeps high coding efficiency. To minimize synchronization time of multiple parallel slices, we also propose a synchronization method to determinate whether the parallel slice could be independently decoded or not. Experimental results shows that we achieved 27.5% (40.7%) speed-up by parallelism with bit-rate increase of 3.4% (2.7%) for CIF sequences (720p sequences) by implementing the proposed algorithm on the H.264/AVC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.5
• /
• pp.555-564
• /
• 2016

This paper proposes a time slot allocation scheme for military patrol environments. This proposal comes from analysis of traffic properties in a military patrol environment. In the near future, robots are expected to explore enemy grounds and measure threat, taking the place of human patrol. In order to control such robots, control messages must be extremely accurate. One mistake from the control center could cause a tragedy. Thus, high reliability must be guaranteed. Another goal is to maintain a continual flow of multimedia data sent from patrol robots. That is, QoS (Quality of Service) must be guaranteed. In order to transmit data while fulfilling both attributes, the per-path based centralized TDMA slot allocation scheme is recommended. The control center allocates slots to robots allowing synchronization among robots. Slot allocation collisions can also be avoided. The proposed scheme was verified through the ns-3 simulator. The scheme showed a higher packet delivery ratio than the algorithm in comparison. It also performed with shorter delay time in the downlink traffic transmission scenario than the algorithm in comparison.