8036895
The case for multipath multimedia transport over wireless ad hoc networks
Real-time multimedia transport has stringent bandwidth, delay, and loss requirements. Supporting this application in current wireless ad hoc networks is a challenge. Such networks are characterized with frequent link failures, as well as congestion. Consequently, data packets are dropped when a link fails or congestion occurs, resulting in low received quality. In addition, a realtime multimedia service may be unavailable when a particular server is unreachable. In this article, we make the case for using multipath transport for realtime multimedia services in wireless ad hoc networks, which provides a unified solution to the above problems. We review existing work on multipath multimedia transport, and discuss the advantages, as well as related issues, of using multipath transport for realtime multimedia transport.
8996068
A mobile sensor network using autonomously controlled animals
Recent research has demonstrated that it is possible to use wireless communication to deliver brain stimulation to guide the movements of rats through a variety of terrains by stimulating multiple brain regions to produce stimulus cues for various commanded movements. The rats can be controlled not only while in direct line of sight of a human controller, but also by teleoperation, using signals transmitted from a wireless video camera mounted on the animal's backpack. Remotely guided rats or other animals are ideal for search and rescue operations because they are highly adept at negotiating difficult 3D terrain, in both light and dark. The animals autonomously choose their own methods for traversing particular obstacles. Primarily for these reasons, they can be more effective than mechanical robots in search and rescue applications. They can also be trained to detect and home in on specific sensory targets, allowing them to be used as biosensors. To meet these challenges, a cluster of interrelated research studies, including network topology design, routing algorithms, media access control techniques, radio resource management, radio propagation modeling, and mobility modeling are comprised. In this paper, the authors have designed and implemented the hardware of backpacks and set up a simple wireless ad hoc network by using static routing.
15288744
Cost/performance tradeoff of n-select square root implementations
Hardware square-root units require large numbers of gates even for iterative implementations. In this paper we present four low-cost high-performance fully-pipelined n-select implementations (nS-Root) based on a non-restoring-remainder square root algorithm. The nS-Root uses a parallel array of carry-save adders (CSAs). For a square root bit calculation, a CSA is used once. This means that the calculations can be fully pipelined. It also uses the n-way root-select technique to speedup the square root calculation. The cost/performance evaluation shows that n=2 or n=2.5 is a suitable solution for designing a high-speed fully pipelined square root unit while keeping the low-cost.
14632183
Collection of network information in active networks
Collection of information about the state of the network is very important for applications both in active networks and in traditional passive networks. However, the existing methods for the collection and prediction of network state cannot meet the needs of complex and intelligent applications. Active networks provide an environment that supports the injection and execution of application-specified codes in the network nodes, and consequently suggest possibilities for the solving of such a problem. In this article we present a new method for the collection of network state information by describing how active network techniques can be used to collect this information more freely and in a user-specific way. We give also an implementation of this approach to collect network resource information and evaluate it by measurements. By using this method, users can specify both the content and the format of the network resource information that they want to acquire as well as nodes at which they want to gather these information.
8805137
Classification of Text Documents
The exponential growth of the internet has led to a great deal of interest in developing useful and efficient tools and software to assist users in searching the Web. Document retrieval, categorization, routing and filtering can all be formulated as classification problems. However, the complexity of natural languages and the extremely high dimensionality of the feature space of documents have made this classification problem very difficult. We investigate four different methods for document classification: the naive Bayes classifier, the nearest neighbour classifier, decision trees and a subspace method. These were applied to seven-class Yahoo news groups (business, entertainment, health, international, politics, sports and technology) individually and in combination. We studied three classifier combination approaches: simple voting, dynamic classifier selection and adaptive classifier combination. Our experimental results indicate that the naive Bayes classifier and the subspace method outperform the other two classifiers on our data sets. Combinations of multiple classifiers did not always improve the classification accuracy compared to the best individual classifier. Among the three different combination approaches, our adaptive classifier combination method introduced here performed the best. The best classification accuracy that we are able to achieve on this seven-class problem is approximately 83%, which is comparable to the performance of other similar studies. However, the classification problem considered here is more difficult because the pattern classes used in our experiments have a large overlap of words in their corresponding documents.
8401209
Optimal Traffic-Oblivious Energy-Aware Routing for Multihop Wireless Networks
Energy efficiency is an important issue in multihop wireless networks with energy concerns. Usually it is achieved with accurate knowledge of the traffic pattern and/or the current network information such as the remaining energy level. We investigate the problem of designing a routing scheme to minimize the maximum energy utilization of a multihop wireless network with weak assumption of the traffic pattern and without ongoing collection of network information. We develop polynomial size LP models to design such a routing scheme. We discuss generalizations of the LP models to various radio transmission models. In an interference-limited scenario, we show how to guarantee schedulability of the oblivious routing. We present an extension to consider lossy links. We also discuss implementation issues. The LP models achieve performance close to what an oracle can achieve in the performance study. The results for multihop wireless networks with a single sink are especially good. We make a first stride in designing a traffic-oblivious energy-aware routing framework in multihop wireless networks.
36131731
Disclosure Risk in Dynamic Two-Dimensional Contingency Tables (Extended Abstract)
Two-dimensional contingency tables are central products of many information organizations such as statistical agencies, census bureaus, and health insurance information agencies. In a contingency table, any sensitive information about individuals must be protected, while some aggregated information can be released. The disclosure risk is that the aggregated information can be used to infer some sensitive information about individuals. Since the disclosure of sensitive information may compromise privacy, confidentiality, and national interests, one needs to carefully assess the latent risk of disclosure and take effective methods to protect the data.