Prasant Mohapatra

Power conservation and quality of surveillance in target tracking sensor networks

Target tracking is an important application of wireless sensor networks. In this application, the sensor nodes collectively monitor and track the movement of an event or target object. The network operations have two states: the surveillance state during the absence of any event of interest, and the tracking state which is in response to any moving targets. Thus, the power saving operations, which is of critical importance for extending network lifetime, should be operative in two different modes as well. In this paper, we study the power saving operations in both states of network operations. During surveillance state, a set of novel metrics for quality of surveillance is proposed specifically for detecting moving objects. In the tracking state, we propose a collaborative messaging scheme that wakes up and shuts down the sensor nodes with spatial and temporal preciseness. This study, which is a combination of theoretical analysis and simulated evaluations, quantifies the trade-off between power conservation and quality of surveillance while presenting guidelines for efficient deployment of sensor nodes for target tracking application.

Medium access control in wireless sensor networks

Limited energy, computational, and communication resources complicate protocol design within sensor networks and prevent the application of many techniques used within other networks. Constraints on sensor node cost further restrict which technologies sensor networks may utilize. Despite much attention in recent years, researchers have yet to achieve the goal of long term, independent operation of sensor network deployments under these constraints. One research direction considers the energy expended performing communication functionality. Medium access protocols provide the greatest influence over communication mechanisms and provide the most direct influence over the utilization of the transceiver, the largest energy consumer in most sensor nodes. We present a discussion of medium access control concepts in relation to sensor networks and examine previous wireless medium access control protocols to illustrate how they do not match the requirements and characteristics of sensor networks. We then present several protocols recently proposed in the literature specifically for sensor networks.

FIREMAN: a toolkit for firewall modeling and analysis

Security concerns are becoming increasingly critical in networked systems. Firewalls provide important defense for network security. However, misconfigurations in firewalls are very common and significantly weaken the desired security. This paper introduces FIREMAN, a static analysis toolkit for firewall modeling and analysis. By treating firewall configurations as specialized programs, FIREMAN applies static analysis techniques to check misconfigurations, such as policy violations, inconsistencies, and inefficiencies, in individual firewalls as well as among distributed firewalls. FIREMAN performs symbolic model checking of the firewall configurations for all possible IP packets and along all possible data paths. It is both sound and complete because of the finite state nature of firewall configurations. FIREMAN is implemented by modeling firewall rules using binary decision diagrams (BDDs), which have been used successfully in hardware verification and model checking. We have experimented with FIREMAN and used it to uncover several real misconfigurations in enterprise networks, some of which have been subsequently confirmed and corrected by the administrators of these networks

QRON: QoS-aware routing in overlay networks

Recently, many overlay applications have emerged in the Internet. Currently, each of these applications requires their proprietary functionality support. A general unified framework may be a desirable alternative to application-specific overlays. We introduce the concept of overlay brokers (OBs). We assume that each autonomous system in the Internet has one or more OBs. These OBs cooperate with each other to form an overlay service network (OSN) and provide overlay service support for overlay applications, such as resource allocation and negotiation, overlay routing, topology discovery, and other functionalities. The scope of our effort is the support of quality-of-service (QoS) in overlay networks. Our primary focus is on the design of QoS-aware routing protocols for overlay networks (QRONs). The goal of QRON is to find a QoS-satisfied overlay path, while trying to balance the overlay traffic among the OBs and the overlay links in the OSN. A subset of OBs, connected by the overlay paths, can form an application specific overlay network for an overlay application. The proposed QRON algorithm adopts a hierarchical methodology that enhances its scalability. We analyze two different types of path selection algorithms. We have simulated the protocols based on the transit-stub topologies produced by GT-ITM. Simulation results show that the proposed algorithms perform well in providing a QoS-aware overlay routing service.

Qos in mobile a hoc networks

The widespread use of mobile and handheld devices is likely to popularize ad hoc networks, which do not require any wired infrastructure for intercommunication. The nodes of mobile ad hoc networks operate as end hosts as well as routers. They intercommunicate through single-hop and multihop paths in a peer-to-peer fashion. With the expanding scope of applications of MANETs, the need to support QoS in these networks is becoming essential. This article provides a survey of issues in supporting QoS in MANETs. We have considered a layered view of QoS provisioning in MANETs. In addition to the basic issues in QoS, the report describes the efforts on QoS support at each of the layers, starting from the physical anti going up to the application layer. A few proposals on interlayer approaches to QoS provisioning are also addressed. The article concludes with a discussion on the future directions and challenges in the areas of QoS support in MANETs.

Trust Computations and Trust Dynamics in Mobile Adhoc Networks: A Survey

Trust is an important aspect of mobile adhoc networks (MANETs). It enables entities to cope with uncertainty and uncontrollability caused by the free will of others. Trust computations and management are highly challenging issues in MANETs due to computational complexity constraints, and the independent movement of component nodes. This prevents the direct application of techniques suited for other networks. In MANETs, an untrustworthy node can wreak considerable damage and adversely affect the quality and reliability of data. Therefore, analyzing the trust level of a node has a positive influence on the confidence with which an entity conducts transactions with that node. In this work we present a detailed survey on various trust computing approaches that are geared towards MANETs. We highlight the summary and comparisons of these approaches. In addition, we analyze various works on trust dynamics including trust propagation, prediction and aggregation algorithms, the influence of network dynamics on trust dynamics and the impact of trust on security services.

Efficient overlay multicast for mobile ad hoc networks

Overlay multicast protocol builds a virtual mesh spanning all member nodes of a multicast group. It employs standard unicast routing and forwarding to fulfill multicast functionality. The advantages of this approach are robustness and low overhead. However, efficiency is an issue since the generated multicast trees are normally not optimized in terms of total link cost and data delivery delay. In this paper, we propose an efficient overlay multicast protocol to tackle this problem in MANET environment. The virtual topology gradually adapts to the changes in underlying network topology in a fully distributed manner. A novel source-based Steiner tree algorithm is proposed for constructing the multicast tree. The multicast tree is progressively adjusted according to the latest local topology information. Simulations are conducted to evaluate the tree quality. The results show that our approach solves the efficiency problem effectively.

Visible Light Communication, Networking, and Sensing: A Survey, Potential and Challenges

The solid-state lighting is revolutionizing the indoor illumination. Current incandescent and fluorescent lamps are being replaced by the LEDs at a rapid pace. Apart from extremely high energy efficiency, the LEDs have other advantages such as longer lifespan, lower heat generation, and improved color rendering without using harmful chemicals. One additional benefit of LEDs is that they are capable of switching to different light intensity at a very fast rate. This functionality has given rise to a novel communication technology (known as visible light communication-VLC) where LED luminaires can be used for high speed data transfer. This survey provides a technology overview and review of existing literature of visible light communication and sensing. This paper provides a detailed survey of 1) visible light communication system and characteristics of its various components such as transmitter and receiver; 2) physical layer properties of visible light communication channel, modulation methods, and MIMO techniques; 3) medium access techniques; 4) system design and programmable platforms; and 5) visible light sensing and application such as indoor localization, gesture recognition, screen-camera communication, and vehicular networking. We also outline important challenges that need to be addressed in order to design high-speed mobile networks using visible light communication.

An analytical model for the energy hole problem in many-to-one sensor networks

In a many-to-one sensor network, all sensor nodes generate CBR data and send them to a single sink via multihop transmissions. Sensor nodes sitting around the sink need to relay more traffic and suffer much faster energy consumption rates (ECR), and thus have much shorter expected lifetime. This may result in severe consequences such as early dysfunction of the entire network. While this phenomenon was reported previously in the existing literature, there is a lack of an analytical model on the characteristics of this issue. In this paper we present a mathematical model and characterize the energy hole problem. Using our model, we investigate the effectiveness of some existing approaches towards mitigating this problem in a formal manner. We have used simulation results to validate our analysis.

Exploiting Multiple-Antenna Diversity for Shared Secret Key Generation in Wireless Networks

Generating a secret key between two parties by extracting the shared randomness in the wireless fading channel is an emerging area of research. Previous works focus mainly on single-antenna systems. Multiple-antenna devices have the potential to provide more randomness for key generation than single-antenna ones. However, the performance of key generation using multiple-antenna devices in a real environment remains unknown. Different from the previous theoretical work on multiple-antenna key generation, we propose and implement a shared secret key generation protocol, Multiple-Antenna KEy generator (MAKE) using off-the-shelf 802.11n multiple-antenna devices. We also conduct extensive experiments and analysis in real indoor and outdoor mobile environments. Using the shared randomness extracted from measured Received Signal Strength Indicator (RSSI) to generate keys, our experimental results show that using laptops with three antennas, MAKE can increase the bit generation rate by more than four times over single-antenna systems. Our experiments validate the effectiveness of using multi-level quantization when there is enough mutual information in the channel. Our results also show the trade-off between bit generation rate and bit agreement ratio when using multi-level quantization. We further find that even if an eavesdropper has multiple antennas, she cannot gain much more information about the legitimate channel.