Mobile Ad hoc Networking: Imperatives and Challenges

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, "ad-hoc" network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET\u27s characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future

Comparison of Two Self-organization and Hierarchical Routing Protocols for Ad Hoc Networks

International audienceIn this article, we compare two self-organization and hierarchical routing protocols for ad hoc networks. These two protocols apply the reverse approach from the classical one, since they use a reactive routing protocol inside the clusters and a proactive routing protocol between the clusters. We compare them regarding the cluster organization they provide and the routing that is then performed over it. This study gives an idea of the impact of the use of recursiveness and of the partition of the DHT on self-organization and hierarchical routing in ad hoc networks

Peripheral Routing Protocol – a new routing protocol proposal for a realistic WSN mobility model

Wireless sensor networks (WSNs) are changing our way of life just as the internet has revolutionized the way people communicate with each other. Future wireless networks are envisioned to be robust, have simple and efficient communication between nodes and self-organizing dynamic capabilities. When new nodes join in, a self-configuring network has to have the ability to include these nodes in its structure in real time, without human or machine interference. The need for a destination node (D) which moves at the periphery of wireless sensor networks can be argued from different points of view: the first is that different WSN scenarios require data gathering in such a way; the second point is that this type of node movement maximizes network lifetime because it offers path diversity preventing the case where the same routes are used excessively. However the peripheral movement model of the mobile destination does not resemble any mobility models presented in the WSN literature. In this thesis a new realistic WSN sink mobility model entitled the “Marginal Mobility Model” (MMM) is proposed. This was introduced for the case when the dynamic destination (D), moving at the periphery, frequently exits and enters the WSN coverage area. We proved through Qualnet simulations that current routing protocols recommended for Mobile Ad Hoc Networks (MANETs) do not support this sink mobility model. Because of this, a new routing protocol is proposed to support it called the Peripheral Routing Protocol (PRP). It will be proven through MATLAB simulations that, for a military application scenario where D’s connectivity to the WSN varies between 10%-95%, compared with the 100% case, PRP outperforms routing protocols recommended for MANETs in terms of throughput (T), average end to end delay (AETED) and energy per transmitted packet (E). Also a comparison will be made between PRP and Location-Aided Routing (LAR) performance when D follows the MMM. Analytical models for both PRP and LAR are proposed for T and E. It is proved through MATLAB simulations that, when compared with LAR, PRP obtains better results for the following scenarios: when the WSN size in length and width is increased to 8000 m and one packet is on the fly between sender and sink, PRP sends 103% more data and uses 84% less energy; when more data packets are on the fly between sender and sink, PRP sends with 99.6% more data packets and uses 81% less energy; when the WSN density is increased to 10,000 nodes PRP uses 97.5% less energy; when D’s speed in increased to 50 Km/h, PRP sends 74.7% more data packets and uses 88.4% less energy

Fuzzy-Based Distributed Protocol for Vehicle-to-Vehicle Communication

This paper modeled the multihop data-routing in Vehicular Ad-hoc Networks(VANET) as Multiple Criteria Decision Making (MCDM) in four steps. First, the criteria which have an impact on the performance of the network layer are captured and transformed into fuzzy sets. Second, the fuzzy sets are characterized by Fuzzy Membership Functions(FMF) which are interpolated based on the data collected from massive experimental simulations. Third, the Analytical Hierarchy Process(AHP) is exploited to identify the relationships among the criteria. Fourth, multiple fuzzy rules are determined and, the TSK inference system is employed to infer and aggregate the final forwarding decision. Through integrating techniques of MCDM, FMF, AHP, and TSK, we designed a distributed and opportunistic data routing protocol, namely, VEFR (Vehicular Environment Fuzzy Router) which targets V2V (vehicle-to-vehicle) communication and runs in two main processes, Road Segment Selection(RSS) and Relay Vehicle Selection(RVS). RSS is intended to select multiple successive junctions through which the packets should travel from the source to the destination, while RVS process is intended to select relay vehicles within the selected road segment. The experimental results showed that our protocol performs and scales well with both network size and density, considering the combined problem of end-to-end packet delivery ratio and end-to-end latency

A key storage and path key efficient diagonal-based grouping for wireless sensor network

Research into the security of wireless sensor networks, often referred to as WSN, has always been a great challenge due to the limited resources and a rich domain of active research. Recently developed probabilistic key predistribution for WSN groupings are not entirely secure. If an adversary can compromise a certain number of sensors, s/he could reconstruct the keys for rest of the sensors. The objective of this thesis was to develop a storage-efficient and low pathkey consuming grouping scheme for a wireless sensor network. In this thesis, a diagonal-based grouping is proposed to improve the security and performance of key distribution based on the work conducted by Liu, Ning, and Du [1]. Two different types of grouping schemes are presented: diagonal-based grouping and diagonalmin grouping. The step-by-step implementation of these groupings in several types of network orientations is also described. This thesis examines the proposed grouping schemes in terms of the key storage and the length of the pathkey. Finally, the outcomes of this thesis demonstrate that the proposed grouping is more key-storage efficient than are the existing schemes. If there is a lot of data flow across the diagonals, the proposed grouping would demonstrate efficient key utilization

Greedy routing and virtual coordinates for future networks

At the core of the Internet, routers are continuously struggling with ever-growing routing and forwarding tables. Although hardware advances do accommodate such a growth, we anticipate new requirements e.g. in data-oriented networking where each content piece has to be referenced instead of hosts, such that current approaches relying on global information will not be viable anymore, no matter the hardware progress. In this thesis, we investigate greedy routing methods that can achieve similar routing performance as today but use much less resources and which rely on local information only. To this end, we add specially crafted name spaces to the network in which virtual coordinates represent the addressable entities. Our scheme enables participating routers to make forwarding decisions using only neighbourhood information, as the overarching pseudo-geometric name space structure already organizes and incorporates "vicinity" at a global level. A first challenge to the application of greedy routing on virtual coordinates to future networks is that of "routing dead-ends" that are local minima due to the difficulty of consistent coordinates attribution. In this context, we propose a routing recovery scheme based on a multi-resolution embedding of the network in low-dimensional Euclidean spaces. The recovery is performed by routing greedily on a blurrier view of the network. The different network detail-levels are obtained though the embedding of clustering-levels of the graph. When compared with higher-dimensional embeddings of a given network, our method shows a significant diminution of routing failures for similar header and control-state sizes. A second challenge to the application of virtual coordinates and greedy routing to future networks is the support of "customer-provider" as well as "peering" relationships between participants, resulting in a differentiated services environment. Although an application of greedy routing within such a setting would combine two very common fields of today's networking literature, such a scenario has, surprisingly, not been studied so far. In this context we propose two approaches to address this scenario. In a first approach we implement a path-vector protocol similar to that of BGP on top of a greedy embedding of the network. This allows each node to build a spatial map associated with each of its neighbours indicating the accessible regions. Routing is then performed through the use of a decision-tree classifier taking the destination coordinates as input. When applied on a real-world dataset (the CAIDA 2004 AS graph) we demonstrate an up to 40% compression ratio of the routing control information at the network's core as well as a computationally efficient decision process comparable to methods such as binary trees and tries. In a second approach, we take inspiration from consensus-finding in social sciences and transform the three-dimensional distance data structure (where the third dimension encodes the service differentiation) into a two-dimensional matrix on which classical embedding tools can be used. This transformation is achieved by agreeing on a set of constraints on the inter-node distances guaranteeing an administratively-correct greedy routing. The computed distances are also enhanced to encode multipath support. We demonstrate a good greedy routing performance as well as an above 90% satisfaction of multipath constraints when relying on the non-embedded obtained distances on synthetic datasets. As various embeddings of the consensus distances do not fully exploit their multipath potential, the use of compression techniques such as transform coding to approximate the obtained distance allows for better routing performances

Bulletin of scientific and art research : annual report for 2018

The SASA Fund allotted the available resources for the following purposes: scientific and art research projects, scientific publications, international scientific cooperation, the organization of scientific meetings, participation of SASA members and their associates in scientific meetings in the country and abroad, acquisition of scientific literature and other purposes under the SASA Scientific and Art Research Programme. In 2018, the SASA Scientific and Art Research Programme contained 28 projects in the fields of mathematics, physics and earth sciences, 20 in the fields of chemical and biological sciences; 13 in the fields of technical and technological sciences; 28 in the field of medical sciences, 12 in the fields of language and literature; 16 in the field of social sciences; 25 in the field of historical sciences, and 8 in the fields of visual arts and music. During the year, the SASA published 52 editions, including 13 journal issues, 19 collections of papers, 13 catalogues, five monographs, two jubilee bibliographies and Volume XX of the SASA Dictionary, while 1,162 authors published 540 papers. The first-ever commercial Catalogue of the SASA Editions: 2016–2017–2018 (Katalog izdanja SANU: 2016–2017–2018) was prepared and published. In addition, 22 manuscripts were technically processed and prepared for publication; the make-up and cover design of six publications were finished. The SASA maintained regular contact with the National Library of Serbia concerning the preparation of a Cataloguing in Publication (CIP) record for all SASA editions. Fourteen manuscripts in the Serbian language underwent orthographic editing and 15 publications underwent proofreading, thus being prepared for publishing. The Serbian Academy of Sciences and Arts hosted the meeting of the COST (European Cooperation in Science and Technology) Action titled “Maximizing Impact of Research in Neurodevelopmental Disorders”. It was the first formal meeting of the COST Action which has so far been joined by about 50 researchers from 20 European countries. During 2018, two lecture cycles were held: “The Fascinating World of Nanoscience and Nanotechnology” (Fascinantni svet nanonauke i nanotehnologije) and “Geohazard in 21st Century Serbia: Knowledge Is the Best Bulwark Against the Elements” (Geohazard u Srbiji u 21. veku – Znanje je najbolji bedem protiv stihije), totalling 11 lectures. In 2018, at the proposal of the SASA Departments and SASA Executive Board, 12 lectures were held. Pursuant to the Decision of the Professional Council of the SASA Library, the SASA Library Day will be celebrated on 14 June. The SASA Library started working on this day, when it received the first books from Dimitrije Tirol. Its first librarian was Konstantin Bogdanović. The SASA Library Day was marked by the celebration honouring Aleksa Šantić. In 2018, the SASA Library organized 17 forums. It presented 18 books and 13 collections of papers by SASA members, SASA editions, as well as the research institutes and centres founded by the SASA. It staged 12 chamber exhibitions. Pursuant to the Decision of the Professional Council of the SASA Library, the SASA Library Day will be celebrated on 14 June. The SASA Library started working on this day, when it received the first books from Dimitrije Tirol. Its first librarian was Konstantin Bogdanović. The SASA Library Day was marked by the celebration honouring Aleksa Šantić. In 2018, the SASA Library organized 17 forums. It presented 18 books and 13 collections of papers by SASA members, SASA editions, as well as the research institutes and centres founded by the SASA. It staged 12 chamber exhibitions. The SASA Library also published the jubilee Bibliography of Academician Nikola Tasić’s Works, authored by Milena Obradović, and the sixth issue of the SASA Library Forum Almanac (Godišnjak “Tribina Biblioteke SANU”). The 293-page issue of the Almanac contains the presentations given at the forums in 2017. In 2018, the SASA Gallery staged eight thematic exhibitions on its premises: “Stojan Novaković and His Era” (Stojan Novaković i njegovo doba), “So, you are Uroš Predić?“ (Dakle, vi ste taj Uroš Predić), “35 Years of Petnica” (35 godina Petnice), “Mihailo Petrović Alas, the Founding Father of the Serbian School of Mathematics” (Mihailo Petrović Alas, rodonačelnik srpske matematičke škole), “Nedeljko Gvozdenović. On a Quest for Absolute Painting” (Nedeljko Gvozdenović. U potrazi za apsolutnim slikarstvom), “Roman Limes and Cities in Serbia” (Rimski limes i gradovi u Srbiji), 57th October Salon. “The Marvellous Cacophony” (57. Oktobarski salon. Čudo kakofonije), “Marko Čelebonović (1902-1986)”, Retrospective Exhibition (Marko Čelebonović /1902-1986/. Retrospektivna izložba). All exhibitions were accompanied by catalogues, lectures and expert guidance. Six catalogues were printed and one was prepared for printing. The exhibitions staged outside the SASA Gallery included: “SASA Art Collection – Academician Artists” (Umetnička zbirka SANU – likovni umetnici akademici), which toured Požarevac, Leskovac and Svilajnac, and “Olga Jevrić Exhibition – Sculptures” (Izložba Olga Jevrić – skulpture) in Užice. Seven new exhibitions were also prepared. In 2018, the Gallery of the Serbian Academy of Sciences and Arts organized 74 concerts within the relevant cycles. The concert-related activity of the SASA Gallery is headed by Academician Ivan Jevtić. During the year, the SASA Gallery of Science and Technology staged 15 exhibitions, supported by rich accompanying programmes. The names of these exhibitions were “Roma Tribulation in World War I” (Stradanje Roma u Prvom svetskom ratu); “Ivan Djaja. The Belgrade School of Physiology – from the Sorbonne to Belgrade” (Ivan Djaja. Beogradska škola fiziologije – od Sorbone do Beograda); “Brain Awareness Week 2018 – All Sides of Consciousness” (Nedelja svesti o mozgu – Sve strane svesti); “Traditional Architectural Heritage in the Area of the Stara Planina” (Tradicionalno arhitektonsko nasledje u regionu Stare planine); “The History of Toxicology” (Istorija toksikologije); THE POWER OF HERBS – The 70th Anniversary of the Institute for Medicinal Herb Research “Dr Josif Pančić” (MOĆ BILJA – povodom 70 godina rada Instituta za proučavanje lekovitog bilja “Dr Josif Pančić”); “This too Is Serbia, ’68 in Student” (I ovo je Srbija, ’68. u Studentu); “Archaeological Forensics – 20 Years of New Archaeological Invesigations of Vinča” (Forenzika drevnosti – 20 godina novih arheoloških istraživanja lokaliteta Vinča); “Serbian Lexicography from Vuk to the Present Day” (Srpska leksikografija od Vuka do danas); “Jovan Stejić, First Serbian Doctorof Medicine in Restored Serbia” (Jovan Stejić, prvi Srbin doktor medicine u obnovljenoj Srbiji); The Salonika Front, 1916-1918 (Solunski front 1916- 1918); World War One in Miniature (Prvi svetski rat u minijaturi), and ON ARCHITECTURE 2018 (O ARHITEKTURI 2018). The exhibitions were supported by the relevant catalogues (5) and rich accompanying programmes. In 2018, the SASA Archives enriched its holdings by numerous gifts. It finished processing Academician Vasa Čubrilović’s manuscript legacy and Patriarch German Andjelić’s legacy. The processing of Dragoljub Jovanović’s legacy will be finished during the first few months of 2019. The work on organizing the collection held in the Cabinet for Medals was carried out. The electronic Incoming Inventory of the Cabinet was prepared. All decorations were sorted out and placed into archival boxes in order to ensure better protection and facilitate handling. The Central Institute for Conservation conserved 169 decorations. More than 800 decorations were photographed and cataloguing was done in accordance with all museological processing rules. The website and digital presentation were created, and the biographies of all donors were written. The result of this work is the permanent exhibition of the Cabinet for Medals, which was opened on the Day of the Academy on 19 November 2018. During the past year, the SASA archivists catered to 223 researchers. The reference library of the SASA Archives was enriched by 70 new books.Ima izdanje na drugom jeziku: Билтен Фонда САНУ за истраживања у науци и уметности = ISSN 2466-428

Correct-by-Construction Development of Dynamic Topology Control Algorithms

Wireless devices are influencing our everyday lives today and will even more so in the future. A wireless sensor network (WSN) consists of dozens to hundreds of small, cheap, battery-powered, resource-constrained sensor devices (motes) that cooperate to serve a common purpose. These networks are applied in safety- and security-critical areas (e.g., e-health, intrusion detection). The topology of such a system is an attributed graph consisting of nodes representing the devices and edges representing the communication links between devices. Topology control (TC) improves the energy consumption behavior of a WSN by blocking costly links. This allows a mote to reduce its transmission power. A TC algorithm must fulfill important consistency properties (e.g., that the resulting topology is connected). The traditional development process for TC algorithms only considers consistency properties during the initial specification phase. The actual implementation is carried out manually, which is error prone and time consuming. Thus, it is difficult to verify that the implementation fulfills the required consistency properties. The problem becomes even more severe if the development process is iterative. Additionally, many TC algorithms are batch algorithms, which process the entire topology, irrespective of the extent of the topology modifications since the last execution. Therefore, dynamic TC is desirable, which reacts to change events of the topology. In this thesis, we propose a model-driven correct-by-construction methodology for developing dynamic TC algorithms. We model local consistency properties using graph constraints and global consistency properties using second-order logic. Graph transformation rules capture the different types of topology modifications. To specify the control flow of a TC algorithm, we employ the programmed graph transformation language story-driven modeling. We presume that local consistency properties jointly imply the global consistency properties. We ensure the fulfillment of the local consistency properties by synthesizing weakest preconditions for each rule. The synthesized preconditions prohibit the application of a rule if and only if the application would lead to a violation of a consistency property. Still, this restriction is infeasible for topology modifications that need to be executed in any case. Therefore, as a major contribution of this thesis, we propose the anticipation loop synthesis algorithm, which transforms the synthesized preconditions into routines that anticipate all violations of these preconditions. This algorithm also enables the correct-by-construction runtime reconfiguration of adaptive WSNs. We provide tooling for both common evaluation steps. Cobolt allows to evaluate the specified TC algorithms rapidly using the network simulator Simonstrator. cMoflon generates embedded C code for hardware testbeds that build on the sensor operating system Contiki