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Park H.,Ewha Womans University | Thomos N.,Ecole Polytechnique Federale de Lausanne | Thomos N.,Distributed Communication Systems | Frossard P.,Ecole Polytechnique Federale de Lausanne
Signal Processing | Year: 2013

This paper considers a framework where data from correlated sources are transmitted with the help of network coding in ad hoc network topologies. The correlated data are encoded independently at sensors and network coding is employed in the intermediate nodes in order to improve the data delivery performance. In such settings, we focus on the problem of reconstructing the sources at decoder when perfect decoding is not possible due to losses or bandwidth variations. We show that the source data similarity can be used at decoder to permit decoding based on a novel and simple approximate decoding scheme. We analyze the influence of the network coding parameters and in particular the size of finite coding fields on the decoding performance. We further determine the optimal field size that maximizes the expected decoding performance as a trade-off between information loss incurred by limiting the resolution of the source data and the error probability in the reconstructed data. Moreover, we show that the performance of the approximate decoding improves when the accuracy of the source model increases even with simple approximate decoding techniques. We provide illustrative examples showing how the proposed algorithm can be deployed in sensor networks and distributed imaging applications. © 2012 Elsevier B.V.


Julien C.,University of Texas at Austin | Wehrle K.,Distributed Communication Systems
Proceedings - International Conference on Software Engineering | Year: 2013

We introduce SESENA 2013, the fourth in a series of workshops devoted to software engineering for sensor network applications. The workshop took place in San Francisco (USA) on May 21, 2013, in conjunction with the 35th ACM/IEEE International Conference on Software Engineering (ICSE). The goal was to bring together research from both the field of software engineering (SE) and wireless sensor networks (WSN) to engender exchange and discussion on shared research goals and agendas. More information can be found on the workshop website http://www.sesena.info. © 2013 IEEE.


Raza S.,Swedish Institute of Computer Science | Shafagh H.,Swedish Institute of Computer Science | Shafagh H.,Distributed Communication Systems | Hewage K.,Uppsala University | And 3 more authors.
IEEE Sensors Journal | Year: 2013

The Internet of Things (IoT) enables a wide range of application scenarios with potentially critical actuating and sensing tasks, e.g., in the e-health domain. For communication at the application layer, resource-constrained devices are expected to employ the constrained application protocol (CoAP) that is currently being standardized at the Internet Engineering Task Force. To protect the transmission of sensitive information, secure CoAP mandates the use of datagram transport layer security (DTLS) as the underlying security protocol for authenticated and confidential communication. DTLS, however, was originally designed for comparably powerful devices that are interconnected via reliable, high-bandwidth links. In this paper, we present Lithe-an integration of DTLS and CoAP for the IoT. With Lithe, we additionally propose a novel DTLS header compression scheme that aims to significantly reduce the energy consumption by leveraging the 6LoWPAN standard. Most importantly, our proposed DTLS header compression scheme does not compromise the end-to-end security properties provided by DTLS. Simultaneously, it considerably reduces the number of transmitted bytes while maintaining DTLS standard compliance. We evaluate our approach based on a DTLS implementation for the Contiki operating system. Our evaluation results show significant gains in terms of packet size, energy consumption, processing time, and network-wide response times when compressed DTLS is enabled. © 2001-2012 IEEE.


Antonescu A.-F.,SAP | Antonescu A.-F.,Distributed Communication Systems | Robinson P.,SAP | Braun T.,Distributed Communication Systems
Proceedings - IEEE 2nd Symposium on Network Cloud Computing and Applications, NCCA 2012 | Year: 2012

This paper describes a specification language and architecture for managing distributed software and mapped compute, storage and network infrastructure services dynamically, beyond the state of the art in cloud computing. This is referred to as dynamic application topology orchestration, where the mapping and configuration of distributed, interconnected, interdependent application services and infrastructure resources are dynamically adjusted, according to guarantees in Service Level Agreements (SLAs) and operational constraints. The viability and benefits of this architectural approach are compared against simpler strategies, to establish technical and business cases for the associated engineering effort. © 2012 IEEE.


Tosic T.,Ecole Polytechnique Federale de Lausanne | Thomos N.,Ecole Polytechnique Federale de Lausanne | Thomos N.,Distributed Communication Systems | Frossard P.,Ecole Polytechnique Federale de Lausanne
Signal Processing | Year: 2013

We investigate the problem of distributed sensors failure detection in networks with a small number of defective sensors, whose measurements differ significantly from the neighbor measurements. We build on the sparse nature of the binary sensor failure signals to propose a novel distributed detection algorithm based on gossip mechanisms and on Group Testing (GT), where the latter has been used so far in centralized detection problems. The new distributed GT algorithm estimates the set of scattered defective sensors with a low complexity distance decoder from a small number of linearly independent binary messages exchanged by the sensors. We first consider networks with one defective sensor and determine the minimal number of linearly independent messages needed for its detection with high probability. We then extend our study to the multiple defective sensors detection by modifying appropriately the message exchange protocol and the decoding procedure. We show that, for small and medium sized networks, the number of messages required for successful detection is actually smaller than the minimal number computed theoretically. Finally, simulations demonstrate that the proposed method outperforms methods based on random walks in terms of both detection performance and convergence rate. © 2012 Elsevier B.V.


Carlin J.M.E.,Distributed Communication Systems | Trinugroho Y.B.D.,Distributed Communication Systems
Proceedings - NGMAST 2010: 4th International Conference on Next Generation Mobile Applications, Services, and Technologies | Year: 2010

Web 2.0 has been an integral part of modern societies, providing collaboration functionalities between individuals. Innovative and pervasive nature of Web 2.0 services has led telecom operators to a strong competition with internet content providers as over-the-top applications are getting very popular. Services can be created faster in the Web 2.0 world where anyone can develop. It is in contrast with the legacy telecom infrastructure where services are tightly coupled with the underlying access networks. Recently, telecom operators have been rolling out the IMS, which provides an environment for rapid application development of services. However, applications created on top of the IMS are based on SIP, which is not popular in the Web 2.0 domain. This paper proposes a flexible platform for provisioning telecom services that is independent of the underlying communications protocol being deployed. A proof-of-concept implementation that is developed based on the Parlay X specification for telecom service capabilities and information exposures on top of an IMS network is presented, and a brief overview of the performance is given. © 2010 IEEE.


Alizai M.H.,Distributed Communication Systems | Wirtz H.,Distributed Communication Systems | Kirchen B.,Distributed Communication Systems | Wehrle K.,Distributed Communication Systems
Journal of Network and Computer Applications | Year: 2013

Multi-hop wireless networks, such as sensor-, ad hoc- and mesh-nets, can be differentiated in terms of participating devices and usage scenarios. However they share strong characteristics and requirements, such as node cooperation to enable multi-hop forwarding and dynamic routing protocols to deliver packets. As a result of these similarities, protocols designed for all these wireless networks revolve around a common core of functionality, for example coping with link and node dynamics. They differ only in additional network-specific functionality, such as tree routing structures in sensornets, and parameterization, for example buffer sizes. This convergence of functionality and design goals, as well as the sheer number of proposed protocols in each network class, motivates the idea of applying protocols to more than just their one original class. However, network-layer protocols are usually developed for and tested in only one class of wireless network due to the lack of a platform that allows testing of protocols across different classes of networks. As a result, we unnecessarily constrain the range of settings and scenarios in which we test network protocols. In this article, we propose a platform for protocol testing and evaluation in multiple, heterogeneous networks and discuss the requirements and challenges of such a solution. As a first step and case study, we present the detailed architecture of TinyWifi, a platform for executing native sensornet protocols on Linux-driven wireless devices as found in wireless mesh and mobile ad-hoc networks (MANETs). TinyWifi builds on nesC code base that abstracts from TinyOS and enables the execution of nesC-based protocols in Linux. Using this abstraction, we expand the applicability and means of protocol execution from one class of wireless network to another without re-implementation. We demonstrate the generality of TinyWifi by evaluating four well-established protocols on IEEE 802.11 and 802.15.4 based testbeds using a single implementation. Based on the experience of building TinyWifi and the presented evaluation, we deduce the feasibility of a cross-network evaluation platform and sketch the requirements for inclusion of further network classes. © 2013 Elsevier Ltd. All rights reserved.


Hummen R.,Distributed Communication Systems | Hiller J.,Distributed Communication Systems | Wirtz H.,Distributed Communication Systems | Henze M.,Distributed Communication Systems | And 2 more authors.
WiSec 2013 - Proceedings of the 6th ACM Conference on Security and Privacy in Wireless and Mobile Networks | Year: 2013

6LoWPAN is an IPv6 adaptation layer that defines mechanisms to make IP connectivity viable for tightly resource-constrained devices that communicate over low power, lossy links such as IEEE 802.15.4. It is expected to be used in a variety of scenarios ranging from home automation to industrial control systems. To support the transmission of IPv6 packets exceeding the maximum frame size of the link layer, 6LoWPAN defines a packet fragmentation mechanism. However, the best effort semantics for fragment transmissions, the lack of authentication at the 6LoWPAN layer, and the scarce memory resources of the networked devices render the design of the fragmentation mechanism vulnerable. In this paper, we provide a detailed security analysis of the 6LoWPAN fragmentation mechanism. We identify two attacks at the 6LoWPAN design-level that enable an attacker to (selectively) prevent correct packet reassembly on a target node at considerably low cost. Specifically, an attacker can mount our identified attacks by only sending a single protocol-compliant 6LoWPAN fragment. To counter these attacks, we propose two complementary, lightweight defense mechanisms, the content chaining scheme and the split buffer approach. Our evaluation shows the practicality of the identified attacks as well as the effectiveness of our proposed defense mechanisms at modest trade-offs. Copyright 2013 ACM.


Wirtz H.,Distributed Communication Systems | Heer T.,Distributed Communication Systems | Backhaus R.,Distributed Communication Systems | Wehrle K.,Distributed Communication Systems
Proceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM | Year: 2011

Due to the widespread availability of 802.11-compliant devices, the 802.11 ad-hoc mode appears especially suited to set up mobile ad-hoc networks (MANETs). In practice, creating a MANET is challenging because typical mobile devices do not implement the configuration, routing, and name resolution functions required to operate in an ad-hoc scenario. Software restrictions on modern mobile operating systems, such as Android and iOS, even prevent mobile devices from actively participating in ad-hoc networks without circumventing vendor barriers (e.g., acquiring root access). While 802.11 infrastructure mode is not originally meant for ad-hoc establishment of multi-hop networks, it is a commodity in all 802.11-compliant devices. This availability prompts the question whether efficient ad-hoc networks can be formed by solely using 802.11 infrastructure mode. In this paper, we present an approach for 802.11 infrastructure mode ad-hoc networks in which mobile devices simultaneously function as an access point and as a station. To establish multi-hop communication across multiple infrastructure mode networks, they mesh with other access point devices. Our evaluation shows that 802.11 infrastructure ad-hoc networks even outperform 802.11 ad-hoc mode networks in terms of multi-hop throughput. © 2011 ACM.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.95K | Year: 2014

ABSTRACT: Distributed Communication Systems (DCS) proposes to design and develop a solution for integrating tactical weather sensors with mobile devices for dissemination of the sensor data back to the Air Force Weather enterprise. DCS will evaluate communications methods which include military and commercial satellite communications. Wherever possible, DCS"s solution will leverage existing commercial off the shelf technologies to provide a low-cost, low-risk solution. As part of the evaluation of technologies for this solution, DCS will evaluate the use of Iridium Communications Short Burst Data (SBD) service as a communication method and technology developed for the DeLorme inReach. SBD based devices are lightweight, low-power, and have a robust communication link. DCS will also design and develop a mobile application which complies with the relevant DISA Security Requirement Guides for mobile devices. The mobile application will also make use of supplemental encryption where appropriate to ensure information security. BENEFIT: The technology developed during the proposed Phase I effort has applications to state-of-the-art for low cost supervisory control and data acquisition (SCADA) systems for remote areas outside of the range of traditional communication paths.

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