Showing papers by "Wai-Choong Wong published in 2005"
06 Jul 2005
TL;DR: Theoretical analysis and simulation results show that the proposed butterfly-graph based stream authentication scheme outperforms existing schemes in terms of overhead and authentication probability while maintaining the same levels of sender/receiver delay and robustness.
Abstract: In this paper, we propose a butterfly-graph based stream authentication scheme for lossy networks where the streaming packets could be lost in both random and burst ways. Due to the nice properties of butterfly graph, the proposed scheme is quite robust and efficient. Theoretical analysis and simulation results show that the proposed scheme outperforms existing schemes in terms of overhead and authentication probability while maintaining the same levels of sender/receiver delay and robustness.
48 citations
05 Dec 2005
TL;DR: This paper presents a novel target trajectory model adapted from the Gauss-Markov mobility model, formulate the tracking problem as a hierarchical Markov decision process (HMDP) and solve it through neuro-dynamic programming (NDP).
Abstract: Energy awareness is a crucial component in the design of wireless sensor networks at all layers. This paper looks into efficient energy utilization of a target tracking sensor network by predicting a target's trajectory through experience. Whilst this is not new, the chief novelty comes in conserving energy through both dynamic spatial and temporal management of sensors and yet assuming minimal locality information. We present a novel target trajectory model adapted from the Gauss-Markov mobility model, formulate the tracking problem as a hierarchical Markov decision process (HMDP) and solve it through neuro-dynamic programming (NDP). Our HMTT (hierarchical MDP for target tracking) algorithm conserves energy by reducing the rate of sensing (temporal management) but maintains acceptable tracking accuracy through trajectory prediction (spatial management). Analysis and simulation results demonstrate its effectiveness in energy conservation and tracking accuracy against other known target tracking algorithms.
18 citations
10 Oct 2005
TL;DR: A novel routing asynchronous wakeup scheme - Adaptive Wakeup Schedule Function (AWSF), which adapts to deployment topography to support fast routing in sensor networks, and eliminates the "Lonely Node" problem.
Abstract: We propose a novel routing asynchronous wakeup scheme - Adaptive Wakeup Schedule Function (AWSF), which adapts to deployment topography to support fast routing in sensor networks. Unlike most other wakeup schemes such as the random and cyclic designs, AWSF guarantees hard delay bounds, have better average delays and smaller delay variances, and eliminates the "Lonely Node" problem where nodes wakeup to find no communicable neighbours. Since AWSF assumes complete radio turn-off in the "sleep" mode, it is largely different from most data-centric wakeup schemes where the radio modules are only put to "idle" mode for "data snooping" where real energy savings cannot be achieved. We provide simulation results to support our claims and have implemented our solution on real Crossbow Mica2 motes.
15 citations
01 Jan 2005
TL;DR: The theoretical performance of HMTT (hierarchical Markov decision process for target tracking) in the multiple targets case is derived and simulations demonstrate its effectiveness against 2 other predictive tracking algorithms with up to 200% improvement.
Abstract: Classical tracking methods are not concerned with energy efficiency and require precise localisation. We addressed these in our previous work through HMTT (hierarchical Markov decision process for target tracking) that tracks single targets at location granularity. HMTT conserves energy by reducing the rate of sensing but preserves acceptable tracking accuracy through trajectory prediction. In this paper, HMTT is extended for the multiple targets case where the state of clusters could be affected by multiple incoming targets and where multiple updates are required at the lower level. The theoretical performance of HMTT in the multiple targets case is derived and simulations demonstrate its effectiveness against 2 other predictive tracking algorithms with up to 200% improvement.
5 citations
TL;DR: DINCast is built on top of an existing P2P multicast tree and results in a hop efficient dynamic multicast infrastructure and is able to reduce communications delay compared with the original tree-based multicast.
5 citations
06 Jul 2005
TL;DR: By exploring the Laplacian distribution of the wavelet coefficients, a new bit plane entropy coder is proposed in this paper which achieves a 0.75% better loss less performance for 5 level 5/3 wavelet decomposition.
Abstract: Compression ratio and computational complexity are two major factors for a successful image coder. By exploring the Laplacian distribution of the wavelet coefficients, a new bit plane entropy coder is proposed in this paper. Compared with the state-of-the-art JPEG2000 entropy coder (EBCOT), the proposed coder achieves a 0.75% better loss less performance for 5 level 5/3 wavelet decomposition at block size 64 £ 64 and 2.56% at block size 16 £ 16. Experimental results also show PSNR improvements of about 0.13dB at 1bpp and 0.25dB at 2bpp on average for lossy compression. However, the gain in coding performance is not based on increasing computational complexity but in stead a reduction by using a static arithmetic coder which avoids complicated adaptive procedure.
4 citations
14 Nov 2005
TL;DR: A new entropy coder, context-based bit plane Golomb coder (CB-BPGC) for scalable image coding, which achieves better coding performance with lower complexity compared to the state-of-the-art JPEG 2000 entropy coding EBCOT.
Abstract: In this paper, we present a new entropy coder, context-based bit plane Golomb coder (CB-BPGC) for scalable image coding, which achieves better coding performance with lower complexity compared to the state-of-the-art JPEG 2000 entropy coder EBCOT. Because of the direct output lazy bit planes, applying the partial decoding on the corrupted bit planes, and the better compression ratio which may lead to corruption to the less important codestream, CB-BPGC appears more resilient to errors when simulated on the wireless channel based on Rayleigh fading model.
2 citations
27 Jun 2005
TL;DR: Simulations demonstrate that DINloop-based multicast results in less message load needed to form the multicast structure, and the routing table size in other core routers does not increase as the number of multicast group increases, and therefore routing scalability is improved.
Abstract: To overcome scalability and control overhead problems existing in inter-domain multicast, DINloop (data-in-network loop) based multicast with MPLS is proposed. DINloop is a special logical path formed using MPLS label switched paths and it consists of multiple DIN nodes which are core routers that connect to each intra-domain. We use DINloop to manage inter-domain multicast group membership. Facilitated by the DINloop, multiple DIN nodes in the core network easily form a Steiner tree for multicast traffic. Furthermore, traffic for different multicast groups sharing the same path are aggregated through a label stack. Simulations demonstrate that DINloop-based multicast results in less message load needed to form the multicast structure. In addition, the routing table size in other core routers does not increase as the number of multicast group increases, and therefore routing scalability is improved. Finally, the inter-domain multicast delay in DINloop-based multicast is lower than that of a unidirectional tree.
1 citations
07 Apr 2005
TL;DR: Simulations show that DINloop based multicast uses the least message load needed to form the multicast architecture, and the routing table size in the core router does not increase as the number of multicast group increases, and therefore DIN loops increases the routing scalability for inter-domain multicast.
Abstract: To overcome the existing scalability problems, DINloop (Data-in-Network loop) based multicast with MPLS (multiprotocol label switching) is proposed to optimize inter-domain multicast. In our approach, multiple DIN Nodes in the core network form the DINloop using MPLS so that multiple multicast sessions share a single DINloop. We adopts a label stack method to use fewer labels and label switch paths (LSPs) are established between DIN Nodes to create the DINloop. Packet processing module analyzes the coming multicast packet and MPLS Manager assigns a label stack to it. Simulations show that DINloop based multicast uses the least message load needed to form the multicast architecture. In addition, the routing table size in the core router does not increase as the number of multicast group increases, and therefore DINloop based multicast increases the routing scalability for inter-domain multicast. Finally, the multicast delay in DINloop based multicast is moderate lager than other protocols.
1 citations
17 Apr 2005
TL;DR: Simulations show that DINloop-based multicast uses the smallest message number needed to form the multicast structure compared with conventional inter-domain multicast protocols, and therefore the routing scalability is achieved.
Abstract: This paper proposes DINloop (Data-In-Network loop) based multicast with GMPLS (generalizedmultiprotocol label switching) to overcome the scalability problems existing in current inter-domain multicast protocols. In our approach, multiple multicast sessions share a single DINloop instead of constructing individual multicast trees. DINloop is a special path formed using GMPLS to establish LSPs (Label Switched Paths) between DIN Nodes, which are core routers that connect to each intra-domain. We adopt link bundling method to use fewer labels. Packet Processing Module analyzes the coming multicast message and GMPLS Manager assigns a label to it. Then the multicast packet is fast forwarded using label. Simulations show that DINloop-based multicast uses the smallest message number needed to form the multicast structure compared with conventional inter-domain multicast protocols. In addition, the routing table size in core routers does not increase as the number of multicast group increases, and therefore the routing scalability is achieved.
1 citations
17 Apr 2005
TL;DR: Simulations show that DINPeer is able to optimize application-level multicast that when the size of the DINloop is capped within a limit, it can achieve a better performance than native IP multicast and P2P overlay multicast systems.
Abstract: In this paper, we propose a DINPeer middleware to overcome limitations in current peer-to-peer (P2P) overlay systems DINPeer exploits a spiral-ring method to discover an inner ring with relative largest bandwidth to form a DINloop (Data-In-Network loop) DINPeer further integrates DINloop with P2P overlay network The key features of DINPeer include using DINloop to replace a multicast rendezvous point and turning DINloop into a cache to achieve application data persistency Simulations show that DINPeer is able to optimize application-level multicast that when the size of the DINloop is capped within a limit, it can achieve a better performance than native IP multicast and P2P overlay multicast systems
31 Jan 2005
TL;DR: Simulations show that DINPeer is able to optimize P2P communication in a number of ways, such as when the size of the DINloop is capped within a limit, it can achieve a better performance than native IP multicast and P1P overlay multicast systems.
Abstract: In this paper, we propose DINPeer middleware to overcome limitations in current peer-to-peer (P2P) overlay systems. DINPeer exploits a spiral-ring method to discover an inner ring with relative largest bandwidth to form a DINloop (Data-In-Network loop). DINPeer further integrates DINloop with P2P overlay network via node state and routing algorithm. The key features of DINPeer include using DINloop to replace a multicast rendezvous point and turning DINloop into a cache to achieve data persistency. Simulations show that DINPeer is able to optimize P2P communication in a number of ways, such as when the size of the DINloop is capped within a limit, it can achieve a better performance than native IP multicast and P2P overlay multicast systems.
Proceedings Article•
01 Jan 2005
TL;DR: Simulations show that DINPeer improves synchronous and asynchronous collaborations and reduces load completion time in divisible load computing scenario in collaborative computing.
Abstract: In this paper, we propose DINPeer to support both collaborative visualization and collaborative computing by overcoming limitations in current collaborative tools and peer-to-peer (P2P) overlay systems. DINPeer exploits a spiral-ring method to discover an inner ring with relative largest bandwidth to form a DINloop (Data-In-Network loop). DINPeer further integrates DINloop with P2P overlay network. The key features of DINPeer include using DINloop to replace a multicast rendezvous point and turning DINloop into a cache to achieve application data persistency. DINPeer improves current collaborative tools by providing application-level multicast, facilitating synchronous and asynchronous collaborations, and supporting the new strategy for divisible load computing. Simulations show that DINPeer improves synchronous and asynchronous collaborations. Furthermore, DINPeer reduces load completion time in divisible load computing scenario in collaborative computing.