Wireless Video Sensor Networks (WVSNs) have been widely proposed for monitoring spatial environments. Dissimilar from traditional Wireless Sensor Networks (WSNs) where nodes such as thermal and light sensors are often considered in 2D and with omni-directional sensing ranges, the sensing range of a video sensor in WVSNs is deemed as directional and usually cognized as a rectangular pyramid shape in 3D environments. Moreover, within indoor spaces, obstacles such as ceiling lights and furniture can easily block the line-of-sight of a video sensor. These new challenges render the traditional deployment solutions for WSNs or 2D modeling environments as impractical to solve the WVSN deployment problem for 3D indoor monitoring. In this paper, we strive to tackle the WVSN deployment problem for 3D indoor monitoring with the consideration of ensuring coverage, connectivity and obstacle awareness. We first model the general problem in a continuous 3D space to minimize the total number of required video sensors. We then convert it into a discrete version problem by incorporating 3D grids, which can achieve arbitrary approximation precision by adjusting the grid granularity. We develop a series of mechanisms to handle the obstacles in the 3D environment and propose an efficient greedy heuristic algorithm yielding high quality solutions. Based on this, we also propose an enhanced Depth First Search (DFS) algorithm that can not only further improve the solution quality, but also return optimal solutions if given enough time. Our extensive simulations demonstrate the superiority of both our greedy heuristic and enhanced DFS solutions.

Presented herein is a new protocol, RaptorQP2P, for reliable peer-to-peer sharing of large files-currently on the order of hundreds of MB but expected to grow to the terabyte range-over networks. The new protocol features two levels of RaptorQ encoding. At the top layer, the entire file is RaptorQ encoded to yield a collection of source blocks and repair blocks. At the lower layer, each source/repair block is RaptorQ encoded independently to yield a collection of source symbols and repair symbols for the block. The symbols are independently transferred among the peers and when a sufficient number of distinct symbols for a block have been received, whether source or repair, the block can be reconstructed. Similarly, the file can be reconstructed using a sufficient number of arbitrary distinct blocks. With real world traces measured on the BitTorrent system, we have conducted extensive simulations to evaluate and compare the performance of RaptorQP2P and BitTorrent. The results indicate that the new protocol handles network dynamics and peer churn smoothly, has excellent scalability with respect to both file size and user population, and performs well. As an example, for a 512 MB file distributed to 1000 peers, download completion time using the new protocol was found to be approximately 45.5% of the completion time required using BitTorrent.

This paper presents a bandwidth management framework for the support of differentiated-service-aware traffic engineering (DS-TE) in multiprotocol label switching (MPLS) networks. Our bandwidth management framework contains both bandwidth allocation and preemption mechanisms in which the link bandwidth is managed in two dimensions: class type (CT) and preemption priority. We put forward a Max-Min bandwidth constraint model in which we propose a novel "use it or lend it" strategy. The new model is able to guarantee a minimum bandwidth for each CT without causing resource fragmentation. Furthermore, we design three new bandwidth preemption algorithms for three bandwidth constraint models, respectively. An extensive simulation study is carried out to evaluate the effectiveness of the bandwidth constraint models and preemption algorithms. When compared with the existing constraint models and preemption rules, the proposed Max-Min constraint model and preemption algorithms improve not only bandwidth efficiency, but also robustness and fairness. They achieve significant performance improvement for the well-behaving traffic classes in terms of bandwidth utilization and bandwidth blocking and preemption probability. We also provide guidelines for selecting different DS-TE bandwidth management mechanisms.

This paper presents two bandwidth preemption algorithms for two widely deployed bandwidth constraint models supporting differentiated service aware traffic engineering: the maximum allocation model and the Russian doll model. Our designs aim at achieving preemption fairness and performance robustness, in addition to the objectives of minimizing the preemption disruption to the existing connections. We propose that the preemption decision be made not only on the basis of priority level, but also on the basis of the bandwidth reservation status and bandwidth constraint model characteristics. Simulation results show that the proposed preemption algorithms achieve significant performance improvement in terms of both bandwidth blocking and preemption rate and bandwidth utilization.

We present two algorithms for transmitting the jittered constant bit rate (CBR) traffic on the upstream channel in broadband wireless access (BWA) systems: a calibration algorithm and a scheduling algorithm. The high priority CBR service class is used to transmit the voice traffic because of its stringent QoS requirements. Our design is aimed at supporting stringent QoS requirements and obtaining high utilization of the upstream bandwidth. Simulation results are presented to demonstrate the effectiveness of our algorithms in achieving high bandwidth utilization and the good traffic performance in terms of both cell loss ratio and mean queuing delay.

We present a bandwidth management algorithm for supporting differentiated-service-aware traffic engineering. The algorithm contains both bandwidth allocation and preemption schemes, in which the link bandwidth is managed in two dimensions: class type and preemption priority. For the purpose of achieving simple, effective and non-fragmentation bandwidth allocation, we establish a novel "use it or lend it" bandwidth management model, which is implemented by an innovative technique of separating the reserved bandwidth information into three colored matrices. A new bandwidth preemption rule is proposed by extending the basic preemption rule in the standard. Our algorithm has been prototyped in the C programming language, and experimental results are presented to demonstrate the effectiveness of our algorithm.

We demonstrate in this paper how to improve the resource utilization in the context of a network based on the rate-controlled service (RCS) discipline. We propose to allow a small loss probability at the traffic shaper, and analyze the impact of various traffic shaping schemes on the network resource utilization. Our analysis establishes that there exists conditions under which our proposed statistical traffic shaping is more beneficial than lossless shaping for improving the network resource utilization. Several design criteria are also obtained from the analysis. Performance evaluation shows that our proposed statistical traffic shaping can achieve a higher level of network resource utilization than lossless traffic shaping in previous works.

We present an admission control scheme for real-time VBR traffic. The deterministic guarantee on the end-to-end delay bound is adopted as the measure of quality-of-service (QoS). The network environment of our admission control algorithm is the connection-oriented network, in which every network node uses the rate-controlled service (RCS) discipline based on the earliest deadline first (EDF) scheduling policy. Unlike the previous studies, this paper focuses on designing an efficient bandwidth allocation scheme, in which the service curve and the spare capacity curve are two important terminologies employed. Experiments using the parameters derived from some real video traces show that our algorithm performs better than previous ones in terms of both the network bandwidth utilization and the computational time needed.

We propose a new operating mechanism for the rate-controller in the ATM network. This mechanism can fulfill the same function as the "traditional" leaky bucket scheme, but it allows a simple queuing analysis. An analysis is developed to study the statistical performance of the proposed rate-controller, including the cell delay distribution, the cell loss ratio, and the characterization of the output. Numerical experiments are conducted to illustrate the analysis results and to provide insights into the system design.