We propose a radically new family of geometric graphs, i.e., Hypocomb (HC), Reduced Hypocomb (RHC), and Local Hypocomb (LHC). HC and RHC are extracted from a complete graph; LHC is extracted from a Unit Disk Graph (UDG). We analytically study their properties including connectivity, planarity, and degree bound. All these graphs are connected (provided that the original graph is connected) planar. Hypocomb has unbounded degree while Reduced Hypocomb and Local Hypocomb have maximum degree 6 and 8, respectively. To our knowledge, Local Hypocomb is the first strictly localized, degree-bounded planar graph computed using merely 1-hop neighbor position information. We present a construction algorithm for these graphs and analyze its time complexity. Hypocomb family graphs are promising for wireless ad hoc networking. We report our numerical results on their average degree and their impact on FACE routing. We discuss their potential applications and pinpoint some interesting open problems for future research.

In mobile-beacon assisted sensor localization, beacon mobility scheduling aims to determine the best beacon trajectory so that each sensor receives sufficient beacon signals and becomes localized with minimum delay. We propose a novel DeteRministic dynamic bEAcon Mobility Scheduling (DREAMS) algorithm, without requiring any prior knowledge of the sensory field. In this algorithm, the beacon trajectory is defined as the track of Depth-First Traversal (DFT) of the network graph, thus deterministic. The mobile beacon performs DFT dynamically, under the instruction of nearby sensors on the fly. It moves from sensor to sensor in an intelligent heuristic manner according to Received Signal Strength (RSS)-based distance measurements. We prove that DREAMS guarantees full localization (every sensor is localized) when the measurements are noise-free, and derive the upper bound of beacon total moving distance in this case. Then, we suggest to apply node elimination and Local Minimum Spanning Tree (LMST) to shorten beacon tour and reduce delay. Further, we extend DREAMS to multibeacon scenarios. Beacons with different coordinate systems compete for localizing sensors. Loser beacons agree on winner beacons' coordinate system, and become cooperative in subsequent localization. All sensors are finally localized in a commonly agreed coordinate systems. Through simulation we show that DREAMS guarantees full localization even with noisy distance measurements. We evaluate its performance on localization delay and communication overhead in comparison with a previously proposed static path-based scheduling method.

We propose a radically new family of geometric graphs, i.e., Hypocomb, Reduced Hypocomb and Local Hypocomb. The first two are extracted from a complete graph; the last is extracted from a Unit Disk Graph (UDG). We analytically study their properties including connectivity, planarity and degree bound. All these graphs are connected (provided the original graph is connected) planar. Hypocomb has unbounded degree while Reduced Hypocomb and Local Hypocomb have maximum degree 6 and 8, respectively. To our knowledge, Local Hypocomb is the first strictly-localized, degree-bounded planar graph computed using merely 1-hop neighbor position information. We present a construction algorithm for these graphs and analyze its time complexity. Hypocomb family graphs are promising for wireless ad hoc networking. We report our numerical results on their average degree and their impact on FACE routing. We discuss their potential applications and some open problems.

In mobile-beacon assisted sensor localization, beacon mobility scheduling aims to determine the best beacon trajectory so that each sensor receives sufficient beacon signals with minimum delay. We propose a novel DeteRministic bEAcon Mobility Scheduling (DREAMS) algorithm, without requiring any prior knowledge of the sensory field. In this algorithm, beacon trajectory is defined as the track of depth-first traversal (DFT) of the network graph, thus deterministic. The mobile beacon performs DFT under the instruction of nearby sensors on the fly. It moves from sensor to sensor in an intelligent heuristic manner according to RSS (Received Signal Strength)-based distance measurements. We prove that DREAMS guarantees full localization (every sensor is localized) when the measurements are noise-free. Then we suggest to apply node elimination and topology control (Local Minimum Spanning Tree) to shorten beacon tour and reduce delay. Through simulation we show that DREAMS guarantees full localization even with noisy distance measurements. We evaluate its performance on localization delay and communication overhead in comparison with a previously proposed static path based scheduling method.

Knowledge discovery and data analysis in resource constrained wireless sensor networks faces different challenges. One of the main challenges is to identify misbehaviors or anomalies with high accuracy while minimizing energy consumption in the network. In this paper, we extend a previous work of us and we present an algorithm for temporal anomalies detection in wireless sensor networks. Our experiments results show that our algorithm can efficiently and accurately detect anomalies in sensor measurements. It also produces low false alarm rate for slow variation time series measurements without harvesting the source of energy.

A primary purpose of sensing in a sensor network is to collect and aggregate information about a phenomenon of interest. The batteries on today's wireless sensor barely last a few days, and nodes typically expend a lot of energy in computation and wireless communication. Hence, the energy efficiency of the system is a major issue. Different representative mechanisms has been proposed to achieve a long lived sensors such as “clustering mechanisms” as well as Aggregation techniques to reduce the amount of data communication generated by sensors. Depending on the data type, ARMA series and forecasting are possible ways to reduce data transmission. In this work, we adopt single-hop clustering mechanism where all sensor nodes in a cluster communicate with their Cluster-Head (or sink) via single hop (such as In/On body sensors for personal health monitoring,..). We propose different data aggregation algorithms based on the AutoRegressive model, to predict local readings and reduce the communication traffic. We evaluate the performance of our work in terms of communication cost and energy consumption. We also extend our work to enhance the prediction accuracy by estimating dynamic prediction threshold. Our simulation shows that depending on data type, communication overhead and rate can be reduced and a considerable accuracy prediction can be obtained.

Extending the lifetime of wireless sensor networks remains the most challenging and demanding requirement that impedes large-scale deployments. The basic operation in WSNs is the systematic gathering and transmission of sensed data to a base station for further processing. During data gathering, the amount of data can be large sometimes, due to redundant data combined from different sensing nodes in the neighborhood. Thus the data gathered need to be processed before being transmitted, in order to detect and remove redundancy, which can impact the communication traffic and energy consumption of the network in a negative way. In this paper, we propose an algorithm to measure similarity between the data collected toward the base station(relative to a specific event monitoring), so that an aggregator sensor sends a minimum amount of information to the base station in a way that the latter can deduce the source information of sensing neighbors nodes. Further, our experimental results demonstrate that the communication traffic and the number of bits transmitted can be minimized while preserving accuracy on the base station estimations.

We propose a localized sensor localization scheme making full use of controlled mobility of a location-aware actor and the connectivity of the sensor network. It contains two new algorithms: a unscented particle filter (UPF) based localization algorithm and an actor mobility scheduling algorithm. The former is an application of UPF. It enables sensor self-localization using received signal strength indicator and actor position. The latter models actor mobility scheduling as traveling salesman problem and aims at fully localized network and minimized time delay. Navigated by sensors, the actor depth-first traverses a local minimum spanning tree of a connected 3-dominating set of the network.

In most current approaches to software security, security flaws are fixed only after they have been exploited. To increase user confidence in software products, the software industry needs more proactive and durable security solutions by addressing security requirements throughout the software system lifecycle, including requirements and design specification, testing, and maintenance phases. Appropriate security analysis techniques must be used for each of these phases. In this paper, we illustrate an integrated security analysis framework, which combines a quantitative design security analysis technique, with a static program analyzer, which tracks unsafe information flows. We illustrate the framework by presenting a case study based on medical information card

Pervasive computing is the next generation of computing environments. As a result more and more applications are dynamically deployed on a growing set of small safe devices. Applications delivered by different vendors may share code and data while they may not trust one another. We present an information flow analysis for full Java bytecode adapted for applications dedicated to embedded systems. Existing techniques are not well adapted to this domain and are often too complex. To ease embedded operations and reduce overhead, an external static analysis is performed initially, and the results are embedded as annotations within the code and certified at loading time. In contrast with other analysis techniques, our model supports dynamic class loading. We evaluated our model on a business case study involving an electronic wallet for air miles storage and management from the literature. We obtained the same results as the other papers but under more restrictive conditions related to inherent characteristics of embedded environments.