Hyung Rai Oh

An effective mesh-pull-based P2P video streaming system using Fountain codes with variable symbol sizes

In this paper, we propose an effective mesh-pull-based video streaming system over P2P networks using Fountain codes with variable symbol sizes for video-on-demand services. The goal of the proposed system is to provide a stable video streaming service of high quality with minimum computational complexity and a short initial latency over P2P networks. Basically, Fountain codes are adopted in the proposed system to simplify the handshaking procedure, which causes a large initial latency, and to support a robust video streaming service despite packet losses. The proposed Fountain encoding mechanism works by using feedback information to reduce unnecessary encoded symbol generation. In addition, the Fountain code symbol size is continuously adjusted to minimize additional computational overhead required for Fountain encoding/decoding. The proposed system is fully implemented in software and examined over an Internet environment.

Application layer multicast tree for real-time media delivery

This paper presents an application layer multicast tree to minimize the average time delay between the sender and end-systems for the real-time media delivery. The proposed algorithm also takes into account the computing power and the network condition of each end-system as a control variable in order to avoid the undesirable case that end-systems are overloaded considering their limited resources. The multicast tree is constructed by clustering and modified Dijkstras algorithms. Finally, we provide the experimental result and compare the proposed algorithm with other algorithms to show that it can provide an effective solution.

Scalable proxy caching algorithm minimizing client’s buffer size and channel bandwidth ☆

Abstract This paper presents a scalable caching algorithm of proxy server with the finite storage size minimizing client’s buffer size and constant-bit-rate channel bandwidth. Under the general video traffic condition, it is observed that the amount of decreased client’s buffer size and channel bandwidth after caching a video frame depends on the relative frame position in the time axis as well as the frame size. Based on this fact, we propose an effective caching algorithm to select the cached frames by using the normalized buffer size. Finally, experimental results are provided to show the superior performance of the proposed algorithm.

QoS-aware routing and power control algorithm for multimedia service over multi-hop mobile ad hoc network

This paper presents a QoS (quality of service) aware routing and power control algorithm consuming low transmission power for multimedia service over mobile ad hoc network. Generally, multimedia services need stringent QoS over the network. However, it is not easy to guarantee the QoS over mobile ad hoc network since its network resources are very limited and time-varying. Furthermore, only a limited amount of power is available at mobile nodes, which makes the problem more challenging. We propose an effective routing and power control algorithm for multimedia services that satisfies end-to-end delay constraint with low transmission power consumption. The proposed algorithm supports the required bandwidth by controlling each link channel quality over route in a tolerable range. In addition, a simple but effective route maintenance mechanism is implemented to avoid link failures that may significantly degrade streaming video quality. Finally, performance comparison with existing algorithms is presented in respect to traditional routing performance metrics, and an achievable video quality comparison is provided to demonstrate the superiority of the proposed algorithm for multimedia services over mobile ad hoc network. Copyright

Mesh-Pull-Based P2P Video Streaming System Using Fountain Codes

In this work, we propose a simple but effective mesh-pull-based P2P video streaming system using Fountain codes with variable symbol sizes for video-on-demand services. The goal of the proposed system is to provide a stable video streaming service of high quality with a low computational complexity and short initial latency. Fountain codes are adopted in the proposed system to simplify the handshaking procedure which causes a large initial latency, and to support a robust video streaming service. The proposed system works by using feedback information to reduce unnecessary encoded symbol generation. In addition, the Fountain code symbol size is continuously adjusted to minimize additional computational overhead required for Fountain encoding/decoding.

Metafile-Based Scalable Caching and Dynamic Replacing Algorithms for Multiple Videos Over Quality-of-Service Networks

This paper presents metafile-based scalable caching and dynamic replacing algorithms for multiple videos over quality-of-service networks. A metafile for each video includes the cached-frame sequence, which is made by scalable caching algorithm minimizing clients buffer size and channel bandwidth under the general video traffic condition. Based on the metafiles, we propose a caching algorithm for multiple videos to effectively reduce both the buffer size and the required bandwidth and replacing algorithm to dynamically update the cached frames when user access pattern changes. Finally, experimental results are provided to compare the proposed algorithms with various existing caching and replacing algorithms.

A Novel Dynamic and Scalable Caching Algorithm of Proxy Server for Multimedia Objects

This paper presents a novel dynamic and scalable caching algorithm of proxy server with a finite storage size for multimedia objects. Among the multimedia such as text, image, audio and video, video is a dominant component in terms of the performance of proxy server due to its traffic characteristics. For the fast caching process, caching sequences for videos are obtained to decrease both the buffer size and the required bandwidth and saved into metafiles in advance. Then, we present a novel caching and replacing algorithms for multimedia objects based on the metafiles. Finally, experimental results are provided to show the superior performance of the proposed algorithm.

Entire network load-aware cooperative routing algorithm for video streaming over mobile ad hoc networks

In this paper, we present an entire network load-aware cooperative routing algorithm based on IEEE 802.11 multi-rate for video streaming over mobile ad hoc networks. The proposed routing algorithm is designed to minimize the consumed time slots while guaranteeing the required time slots at all the pairs of adjacent nodes over the route and the contention neighbors of these nodes to support the route. Furthermore, the proposed routing algorithm can distribute the network loads well over the entire network. This technology is essential because video streaming applications require stringent quality of service and even larger network resources compared with traditional data services, and these demands may dramatically increase the entire network load and/or cause network congestion. Finally, experimental results are provided to show a performance of the proposed routing algorithm. Copyright

Energy efficient MAC protocol for delay-sensitive data transmission over wireless sensor network

This paper presents an energy efficient medium access control (MAC) protocol for delay-sensitive data transmission over wireless sensor network. In general, energy consumption and delay depend on channel monitoring interval (CMI) and data sensing period at each sensor node. Based on this fact, we propose a new preamble structure to effectively advertise CMI and avoid the overhearing problem. In order to pursue an effective tradeoff between energy consumption and delay, we also develop a CMI determining algorithm that searches for a sub-optimal solution with a low computational complexity in a distributive way. Finally, experimental results are provided to compare the proposed MAC protocol with existing sensor MAC protocols. Copyright

Effective caching algorithm by minimizing normalized buffer size over constant bit rate channel [video servers]

In this work, we present an effective caching algorithm for a proxy server with finite storage size. Under general video traffic conditions, it is observed that the reduced amount of receiver buffer size and channel bandwidth depends on both the frame size and the frame position. To consider this fact, we propose an effective caching algorithm to select the positions of cached frames, based on the normalized buffer size. Finally, experimental results are provided to show the superior performance of the proposed algorithm.