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Publisher: Elsevier   (Total: 3155 journals)

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Showing 1 - 200 of 3155 Journals sorted alphabetically
A Practical Logic of Cognitive Systems     Full-text available via subscription   (Followers: 9)
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 34, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 23, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 96, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 27, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 38, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 5)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 7)
Acta Astronautica     Hybrid Journal   (Followers: 411, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 27, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 2)
Acta de Investigación Psicológica     Open Access   (Followers: 3)
Acta Ecologica Sinica     Open Access   (Followers: 10, SJR: 0.18, CiteScore: 1)
Acta Haematologica Polonica     Free   (Followers: 1, SJR: 0.128, CiteScore: 0)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 259, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 12, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 1, SJR: 1.793, CiteScore: 6)
Acta Poética     Open Access   (Followers: 4, SJR: 0.101, CiteScore: 0)
Acta Psychologica     Hybrid Journal   (Followers: 28, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access   (Followers: 1)
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 6, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 6)
Acute Pain     Full-text available via subscription   (Followers: 14, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 17, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 8, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 10, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 154, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 8, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 14, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 28, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 10, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 11, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 24, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 14, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 2, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 33, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 4)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 27, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 29, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 14)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 12)
Advances in Digestive Medicine     Open Access   (Followers: 9)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 25)
Advances in Ecological Research     Full-text available via subscription   (Followers: 44, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 28, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 8)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 46, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 58, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Genetics     Full-text available via subscription   (Followers: 16, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 8, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 23, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 18, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 11, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 23)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 3)
Advances in Oncobiology     Full-text available via subscription   (Followers: 1)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 12)
Advances in Pharmacology     Full-text available via subscription   (Followers: 16, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 10)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 64)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 6)
Advances in Space Research     Full-text available via subscription   (Followers: 400, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 11, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 34, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 46, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 347, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 11, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 456, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (Followers: 1, SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 17, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 31, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 41, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 4)
Agriculture and Natural Resources     Open Access   (Followers: 3)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 57, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 6, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 11, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 10)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 11, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 9, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 51, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 4, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 4, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 6)
American Heart J.     Hybrid Journal   (Followers: 50, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 54, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 45, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 10)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 34, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 29, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 35, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 47)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 216, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 66, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 28, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 28, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 38, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 7)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 63, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 18, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 5, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 42, SJR: 1.512, CiteScore: 5)
Analytical Biochemistry     Hybrid Journal   (Followers: 180, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 12, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 23, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)
Animal Behaviour     Hybrid Journal   (Followers: 201, SJR: 1.58, CiteScore: 3)

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Journal Cover
Ad Hoc Networks
Journal Prestige (SJR): 0.53
Citation Impact (citeScore): 4
Number of Followers: 11  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1570-8705
Published by Elsevier Homepage  [3155 journals]
  • Geometric Aspects of Probabilistic Broadcasting in Ad Hoc Networks
    • Abstract: Publication date: Available online 15 December 2018Source: Ad Hoc NetworksAuthor(s): Felipe Forero R., Néstor M. Peña T., Nelson L.S. da Fonseca This paper studies pure probabilistic broadcast in ad hoc networks under a variety of topological scenarios, offering a comparison of the performance of broadcast in lattice-like geometric node layouts (e.g. nodes arranged in triangular, square and hexagonal grids) with that in randomly placed nodes. Results suggest that the geometry of the position of nodes has an impact on the success of probabilistic broadcast techniques. Specifically, networks with randomly-placed nodes exhibit a near-ideal (collision-free) behavior, whereas the grid layouts are extremely sensitive to the impact of collisions and interference. To account for the unreliable behavior of broadcast under certain node-distribution geometries, this paper provides an analysis of Signal to Interference ratio for ad hoc networks.
  • DACYCLEM: a Decentralized Algorithm for Maximizing Coverage and Lifetime
           in a Mobile Wireless Sensor Network
    • Abstract: Publication date: Available online 14 December 2018Source: Ad Hoc NetworksAuthor(s): Jean-Matthieu Etancelin, André Fabbri, Frédéric Guinand, Martin Rosalie The goal of Mobile Wireless Sensor Networks (M-WSN) is to sense a specific environment. A commonly considered objective is to organize the work of the sensors such that they monitor the environment as long as possible and cover a surface as large as possible. While most of the time this problem is formulated as a multi-objective optimization problem we present a new decentralized approach for building a connected dominating set (CDS) coupled with attractive and repulsive forces for the movement of sensors in order to maintain the network connectivity. The approach is implemented as a hybrid decentralized algorithm: DACYCLEM (Decentralized Algorithm under Connectivity constraint with mobilitY for Coverage and LifEtime Maximization). The lifetime and the coverage achieved by our approach are the results of the local interactions between the sensors and were not obtained by the application of a direct optimization method. We also introduce a new metric, the speed of coverage, to evaluate the balance between coverage and lifetime. Finally, our simulation results show that one single parameter of DACYCLEM is responsible for the balancing between coverage and lifetime.
  • Lifetime Improvement of Wireless Sensor Network by Information Sensitive
           Aggregation Method for Railway Condition Monitoring
    • Abstract: Publication date: Available online 11 December 2018Source: Ad Hoc NetworksAuthor(s): Manoj Tolani, Sunny, Rajat Kumar Singh Lifetime maximization is an important issue while designing wireless sensor network. One of the ways to increase the lifetime of WSN is to reduce the energy demand of the sensor nodes and cluster head nodes, which can be decreased by filtering out redundant data traffic. A Two-Layer Hierarchal Aggregation (TLHA) protocol has been proposed, which filter out redundant data traffic. Simple aggregation algorithm has been used to classify the sensed data based on their normalized standard deviation for efficient data filtration. The algorithm also performs k-Means based re-classification of data to improve the efficiency of the algorithm. Two-layered redundant data filtration technique has been proposed to classify the data. Aggregation protocol reduces data traffic in lower layer hierarchy (sensor nodes to cluster head node) as well as upper layer hierarchy (cluster head nodes to base station node). In former, Energy efficient Time Division Multiple Access (EA-TDMA) Medium Access Control (MAC) protocol is used while in latter Bit-Map-Assisted (BMA) MAC protocol is used for transmission of data. Simulation and experimental results show that TLHA saves an enormous amount of energy, which finally increases the lifetime of the sensor network. The performance of the proposed TLHA protocol has been compared with already existing protocols viz. Data Aggregation Window Function (DAWF) and Spatial-Temporal Correlation Algorithm (STCA).
  • A Review on Safety Failures, Security Attacks, and Available
           Countermeasures for Autonomous Vehicles
    • Abstract: Publication date: Available online 7 December 2018Source: Ad Hoc NetworksAuthor(s): Jin Cui, Lin Shen Liew, Giedre Sabaliauskaite, Fengjun Zhou Autonomous vehicles (AVs) attract a lot of attention recently. They are expected to assist/replace the human drivers in maneuvering the vehicle, thereby reducing the likelihood of road accidents caused by human error, as a means to improve the road traffic safety. However, AVs have their inherent safety and security challenges, which have to be addressed before they are ready for wide adoption. This paper presents an overview of recent research on AV safety failures and security attacks, as well as the available safety and security countermeasures.
  • PPSHA: Privacy Preserving Secure Handover Authentication Scheme for All
           Application Scenarios in LTE-A networks
    • Abstract: Publication date: Available online 6 December 2018Source: Ad Hoc NetworksAuthor(s): Ruhui Ma, Jin Cao, Dengguo Feng, Hui Li, Yinghui Zhang, Xixiang Lv To ensure secure and seamless handovers inter-Evolved Universal Terrestrial Radio Access Network (E-UTRAN) is a key issue in LTE-A networks. Due to the introduction of Home Evolved NodeB (HeNB), there are three different access modes for the HeNB and the mobility scenarios between the eNB and the HeNB in LTE-A networks are rather complicated. Different handover procedures are executed for different mobility scenarios according to the 3GPP committee, which makes the overall system complex. Thus, it is a key point to propose a unified and secure handover scheme to fit in with all the mobility scenarios in LTE-A networks. In this paper, we propose a secure handover authentication scheme based on the certificateless signcryption technique. Our proposed scheme can achieve the unified and secure handover procedure without sacrificing efficiency. The security and performance evaluations demonstrate that our proposed scheme can meet various security requirements including the perfect forward/backward secrecy and privacy preserving. At the same time, our scheme achieves ideal efficiency.
  • A New CubeSat Design with Reconfigurable Multi-Band Radios for Dynamic
           Spectrum Satellite Communication Networks
    • Abstract: Publication date: Available online 6 December 2018Source: Ad Hoc NetworksAuthor(s): Ian F. Akyildiz, Josep M. Jornet, Shuai Nie Small satellites, or CubeSats, are envisioned as a promising solution for future satellite communication networks because of their low costs and short deployment cycle. Currently, CubeSats communicate at conventionally allocated satellite communication frequencies. However, with the increase in the number of CubeSats, CubeSat-enabled communication systems, and many new use cases, new spectrum bands and a more efficient spectrum usage are needed. In this paper, a novel CubeSat design with reconfigurable multi-band radios for communication in dynamic frequencies is proposed.The multi-band radio design is realized by two complementary approaches, namely, an electronics-based and a photonics-based approach. The multi-band communication covers a wide range from radio frequencies (2–30 GHz), millimeter wave (30–300 GHz), Terahertz band (up to 10 THz), and optical frequencies (with typical bands of 850 nm/350 THz, 1300 nm/230 THz, and 1550 nm/193 THz). A thorough link budget analysis is conducted to demonstrate the potential of the proposed multi-band architecture for space information networks. Key parameters in the satellite constellation design are investigated to explore the feasibility of deployment at different altitudes in the exosphere orbit (500 km and above). A continuous global coverage is demonstrated to serve the Internet of Space Things, a new paradigm for next generation satellite communication networks.
  • Novel Strategies for Path Stability Estimation under Topology Change using
           Hello Messaging in MANETs
    • Abstract: Publication date: Available online 6 December 2018Source: Ad Hoc NetworksAuthor(s): Alamgir Naushad, Ghulam Abbas, Ziaul Haq Abbas, Aris Pagourtzis Path stability estimation due to connectivity failures is one of the key challenges for effective communication under random mobility of network nodes in mobile ad hoc networks (MANETs). Under random movement of network nodes and topology triggered reactive path distribution statistics among the neighboring nodes, there must be a unified model to determine an adequate path stability estimation strategy in MANETs. We present novel link connectivity metrics (LCM) and path distribution analysis (PDA) strategies for path stability estimation under uniform speed and random trajectory of mobile nodes. We also design an adaptive routing model that guarantees effective communication among neighboring nodes inside a cluster. We find that LCM strategy among neighboring nodes is affected by the link expiration time, relative velocity, link connectivity, and link stability metrics in terms of remaining probability for a connected link, link recovery probability, and stability of a path at different time steps of a Markov process. We also find that PDA strategy among neighboring nodes is affected by the link excess life, distribution of path durations, cluster stability, and path duration statistics in terms of throughput and overhead during Hello message(s) communication at different time steps of a Markov process. Analytical and simulation results indicate efficacy of the proposed LCM and PDA strategies by efficiently estimating path stability under topology change, thereby, increasing the global network connectivity.
  • Network Lifetime Improvement using Landmark-Assisted Mobile Sink
           Scheduling for Cyber-Physical System Applications
    • Abstract: Publication date: Available online 6 December 2018Source: Ad Hoc NetworksAuthor(s): Surender Redhu, Rajesh M. Hegde Improving the lifetime of a wireless sensor network is a challenging issue in the development of energy-efficient cyber-physical systems, especially in the design of sensor data aggregation protocols. Mobile sinks are typically used in this context to increase the lifetime of the sensor network in a cyber-physical system. In this work, a landmark-assisted mobile sink scheduling scheme is proposed for designing an energy-efficient data aggregation protocol. A landmark-node identification method along with network clustering is first developed using random walks over network graphs. Subsequently, using the locations of landmark-nodes, a mobile sink scheduling method is developed for sensor data aggregation in an extended Kalman filtering framework. This method is robust since location information of the landmark-nodes is also continuously updated in the Kalman filtering framework. Experiments on identifying landmark-nodes and mobile sink scheduling are conducted on the Intel Berkeley Research Lab dataset and over a real WSN test bed with a Kobuki-Yujin robot. Experimental results obtained for network lifetime analysis and energy-efficiency for various network configurations indicate an improvement over standard methods and are motivating enough for use in practical cyber-physical system applications.
  • QoS-based Dynamic Channel Selection Algorithm for Cognitive Radio based
           Smart Grid Communication Network
    • Abstract: Publication date: Available online 5 December 2018Source: Ad Hoc NetworksAuthor(s): Muhammad Waqas Khan, Muhammad Zeeshan Smart Grid (SG) operation requires multi-way communication among power generation, transmission, distribution, and consumer facilities. The complete SG architecture involves multiple layers of networks stretching from energy control center to consumer facilities and multiple applications with diverse Quality-of-Service (QoS) requirements. To meet these requirements, Cognitive Radio (CR) which offers efficient spectrum utilization and sharing, has been considered as a favorable solution. Due to diverse requirements of latency, data rate and reliability, it is a great challenge to support various SG applications under spectrum sensing uncertainties, Signal-to-Noise Ratio (SNR) variations and availability of desired channel bandwidth. In this paper, we propose a dynamic channel selection algorithm based on Fuzzy Inference System (FIS) capable of selecting the most appropriate available idle channel with desired bandwidth, minimum required SNR and probability of miss detection Pmd. The proposed algorithm utilizes various modes of IEEE Standard 802.22, Wireless Regional Area Network (WRAN), at the physical layer. In case of unavailability of idle channels with required SNR and/or Pmd, we propose a novel approach to select the channel with closest possible parameters aiming to reduce the re-transmission probability and thus achieve the desired throughput, latency and reliability requirements. The performance is compared with existing algorithms to demonstrate the effectiveness and superiority of the proposed algorithm.
  • Use of A Quantum Genetic Algorithm for Coalition Formation in Large-scale
           UAV Networks
    • Abstract: Publication date: Available online 5 December 2018Source: Ad Hoc NetworksAuthor(s): Sajad Mousavi, Fatemeh Afghah, Jonathan D. Ashdown, Kurt Turck Task allocation among a network of heterogeneous resource-constrained Unmanned Aerial Vehicles (UAVs) in an unknown and remote environment is still a challenging problem noting the limited available information about highly dynamic environment, lack of continuous and reliable communication network, and the limited energy and resources available at the UAVs. One solution for this such allocation problem is to form several efficient coalitions of the UAVs, where a complex task is assigned to a group of agents (i.e., a coalition) carrying the required resources/capabilities to perform this task. In this paper, inspired by Quantum Evolutionary Algorithms, we propose a leader-follower coalition formation algorithm in a large-scale UAV network to form the best possible coalitions of agents to accomplish the detected tasks in an unknown environment. Three main objectives have been considered in this coalition formation: (i) minimizing resource consumption in completing the assigned tasks on time; (ii) enhancing the reliability of the coalitions; and (iii) considering the most trustworthy UAVs amid the self-interested UAVs in forming the coalitions. The simulation results demonstrate the superior performances of the proposed model in different scenarios with large number of UAVs compared to existing coalition formation algorithms such as merge-and-split and a famous multi-objective genetic algorithm called NSGA-II.12
  • Celebrating Professor Mario Gerla 75th birthday
    • Abstract: Publication date: Available online 4 December 2018Source: Ad Hoc NetworksAuthor(s): Melodia Tommaso
  • Network Bottlenecks in OLSR Based Ad-hoc Networks
    • Abstract: Publication date: Available online 4 December 2018Source: Ad Hoc NetworksAuthor(s): Nadav Schweitzer, Ariel Stulman, Tirza Hirst, Roy David Margalit, Asaf Shabtai All nefarious players must be able to maximize profit on an attack. In the context of communication networks, part of that need translates to finding the best topological location for the attack. While in static networks this is an easily solvable problem, in mobile ad-hoc networks (manet) having constant topology fluctuations, this becomes a formidable task. Highly important asset nodes are those having numerous paths traversing through them, with bottlenecks being nodes that all data must pass through. Once such nodes are compromised, the damage can be catastrophic. Hence, network defenders must also find these nodes so they can be better protected.In this paper we propose a method that ensures finding such bottleneck nodes (assuming one exists) in olsr based manet, with linear cost. This is accomplished without adding overhead on the network. We experiment and compare, using network simulation tools, multiple types of attackers over a diverse set of topologies.
  • Portability, compatibility and reuse of MAC protocols across different IoT
           radio platforms
    • Abstract: Publication date: Available online 29 November 2018Source: Ad Hoc NetworksAuthor(s): Jan Bauwens, Bart Jooris, Spilios Giannoulis, Irfan Jabandžić, Ingrid Moerman, Eli De Poorter To cope with the diversity of Internet of Things (IoT) requirements, a large number of Medium Access Control (MAC) protocols have been proposed in scientific literature, many of which are designed for specific application domains. However, for most of these MAC protocols, no multi-platform software implementation is available. In fact, the path from conceptual MAC protocol proposed in theoretical papers, towards an actual working implementation is rife with pitfalls. (i) A first problem is the timing bugs, frequently encountered in MAC implementations. (ii) Furthermore, once implemented, many MAC protocols are strongly optimized for specific hardware, thereby limiting the potential of software reuse or modifications. (iii) Finally, in real-life conditions, the performance of the MAC protocol varies strongly depending on the actual underlying radio chip. As a result, the same MAC protocol implementation acts differently per platform, resulting in unpredictable/asymmetrical behavior when multiple platforms are combined in the same network. This paper describes in detail the challenges related to multi-platform MAC development, and experimentally quantifies how the above issues impact the MAC protocol performance when running MAC protocols on multiple radio chips. Finally, an overall methodology is proposed to avoid the previously mentioned cross-platform compatibility issues.
  • Multi-robot Rendezvous Based on Bearing-aided Hierarchical Tracking of
           Network Topology
    • Abstract: Publication date: Available online 28 November 2018Source: Ad Hoc NetworksAuthor(s): Shaocheng Luo, Jonghoek Kim, Ramviyas Parasuraman, Jun Han Bae, Eric T. Matson, Byung-Cheol Min Rendezvous control of multiple robots without losing network connectivity has important implications in multi-robot system including formation control, coordinated task assignments, and cooperative robotic missions. This paper introduces a new coordinate-free, bearing-based algorithm to enable rendezvous of distributed mobile robots at any designated leader robot node using hierarchical tracking of wireless network topology. An assumption is made that the robot can only sense and communicate with their neighbors (i.e., local sensing). The proposed approach preserves connectivity during the rendezvous task, adapts to dynamic changes in the network topology (e.g., losing or re-gaining a communication link), and is tolerant of mobility faults in the robots. We theoretically analyze the proposed algorithm and experimentally demonstrate the approach through simulations and extensive field experiments. The results indicate that the method is effective in a variety of realistic scenarios in which the robots are distributed in a cluttered environment.
  • Adaptive Beacon Broadcast in Opportunistic Routing for VANETs
    • Abstract: Publication date: Available online 28 November 2018Source: Ad Hoc NetworksAuthor(s): Mohammad Naderi, Farzad Zargari, Mohammad Ghanbari Broadcast of beacon messages including geographic coordinates, node speeds, and directions are among the most commonly used methods in routing protocols of VANETs to obtain neighboring positions. Broadcast of periodic beacon messages in fixed time intervals will reduce network performance due to increased channel load and contention. In this paper, an adaptive update strategy for sending beacon messages according to the VANETs’ characteristics (position, speed, and direction) and the nature of broadcast wireless channel in an opportunistic routing strategy is studied. It is based on two rules: 1) an estimation of the lifetime of the links between vehicles’ beacon messages are sent after the expiration of the estimated time to inform their local topology and 2) if the forwarding set of consecutively received data packets is changed, a beacon message is sent to maintain the accuracy of the topology. The simulation results show that the proposed strategy significantly reduces the cost of routing and improves network performance in terms of packet-delivery ratios, average end-to-end delay, and routing overhead.
  • Security in networks of unmanned aerial vehicles for surveillance with an
           agent-based approach inspired by the principles of blockchain
    • Abstract: Publication date: Available online 27 November 2018Source: Ad Hoc NetworksAuthor(s): Iván García-Magariño, Raquel Lacuesta, Muttukrishnan Rajarajan, Jaime Lloret Unmanned aerial vehicles (UAVs) can support surveillance even in areas without network infrastructure. However, UAV networks raise security challenges because of its dynamic topology. This paper proposes a technique for maintaining security in UAV networks in the context of surveillance, by corroborating information about events from different sources. In this way, UAV networks can conform peer-to-peer information inspired by the principles of blockchain, and detect compromised UAVs based on trust policies. The proposed technique uses a secure asymmetric encryption with a pre-shared list of official UAVs. Using this technique, the wrong information can be detected when an official UAV is physically hijacked. The novel agent based simulator ABS-SecurityUAV is used to validate the proposed approach. In our experiments, around 90% of UAVs were able to corroborate information about a person walking in a controlled area, while none of the UAVs corroborated fake information coming from a hijacked UAV.
  • Sensor and Sink Placement, Scheduling and Routing Algorithms for Connected
           Coverage of Wireless Sensor Networks
    • Abstract: Publication date: Available online 22 November 2018Source: Ad Hoc NetworksAuthor(s): Banu Kabakulak A sensor is a small electronic device which has the ability to sense, compute and communicate either with other sensors or directly with a base station (sink). In a wireless sensor network (WSN), the sensors monitor a region and transmit the collected data packets through routes to the sinks. In this study, we propose a mixed–integer linear programming (MILP) model to maximize the number of time periods that a WSN carries out the desired tasks with limited energy and budget. Our sink and sensor placement, scheduling, routing with connected coverage (SPSRC) model is the first in the literature that combines the decisions for the locations of sinks and sensors, activity schedules of the deployed sensors, and data flow routes from each active sensor to its assigned sink for connected coverage of the network over a finite planning horizon. The problem is NP–hard and difficult to solve even for small instances. Assuming that the sink locations are known, we develop heuristics which construct a feasible solution of the problem by gradually satisfying the constraints. Then, we introduce search heuristics to determine the locations of the sinks to maximize the network lifetime. Computational experiments reveal that our heuristic methods can find near optimal solutions in an acceptable amount of time compared to the commercial solver based Two Phase (TP) method.
  • Investigating Physical Security in Stealthy Lattice Wireless Sensor
           Networks Using k-Barrier Coverage
    • Abstract: Publication date: Available online 22 November 2018Source: Ad Hoc NetworksAuthor(s): Habib M. Ammari Any unauthorized access to a critical space is a physical breach in our society that can be viewed as a physical security problem. It is essential to build a barrier that prevents any intruder's attempt to cross it and access a critical area. In this paper, we address the problem of physical security in stealthy lattice wireless sensor networks using a belt of sensors around a critical area. Precisely, we propose a theoretical framework to analyze the k-barrier coverage problem, where any path that crosses this belt intersects with the sensing range of at least k sensors, k ≥ 1. Precisely, we analyze the k-barrier coverage problem from a tiling perspective, where the sensors’ sensing disks are tangential to each other. We study two deterministic sensor deployment strategies, which yield square lattice and hexagonal lattice wireless sensor networks, respectively. First, we introduce the concept of intruder's abstract paths along a k-barrier covered sensor belt region, and compute their number. Second, we propose a polynomial representation of all abstract paths. Third, we compute the number of sensors deployed over a k-barrier covered sensor belt region for both lattices. Fourth, we define the concept of weakly k-barrier covered path crossing a k-barrier covered sensor belt region, and compute its length for both lattices. Also, we define the observability of intruder's abstract path, and compute its value for both lattices. Fifth, we generalize our results for random intruder's moves across a k-barrier covered sensor belt region. Sixth, we corroborate our analysis with simulation results.
  • SeCARA: A Security and Cost-Aware Resource Allocation Method for Mobile
           Cloudlet Systems
    • Abstract: Publication date: Available online 22 November 2018Source: Ad Hoc NetworksAuthor(s): Hassan Raei, Ensieh Ilkhani, Morteza Nikooghadam In the cloudlet architecture of Mobile Cloud Computing (MCC), a number of heavy jobs are offloaded to a private and local cloud, known as cloudlet, to overcome the lack of battery and computation resources of mobile devices. In this architecture, the cloudlet with the help of some public clouds provides the computational resources in the form of virtual machines (VMs) on physical machines (PMs). The users’ requests, based on their security requirements, are classified into different levels which require a certain number of PMs and VMs. On the other hand, the financial budgets of the cloudlet to afford these computational resources are restricted. In addition to the mentioned trade-off between security and cost, other trade-offs emerge among some components of the cost. For example, utilizing a large number of PMs of the cloudlet and public clouds decreases the penalty cost of request rejection; however, other associated costs, such as infrastructure, power consumption, and cooling, augment significantly. Therefore, to minimize the overall cost and to guarantee the security requirements, finding the optimal number of required PMs in all participant clouds, including the cloudlet and public clouds, is recognized as an important issue. To deal with this issue, in the current paper, a security and cost-aware resource allocation (SeCARA) method is proposed. Specifically, the proposed method converts this issue into two cost optimization problems. To compute the components of the cost, the proposed method exploits an analytical performance-security model of a cloudlet to obtain some necessary performance measures, such as request rejection probability. To achieve these significant measures, Markov reward model (MRM) is appropriately used by the performance-security model. Moreover, simulated annealing algorithms are applied to solve the optimization problems. Numerical results demonstrate the strength of the proposed method to identify the optimal number of PMs, for different security types of requests, within an acceptable duration of the time.
  • Trust Management for Secure Cognitive Radio Vehicular Ad Hoc Networks
    • Abstract: Publication date: Available online 22 November 2018Source: Ad Hoc NetworksAuthor(s): Ying He, F. Richard Yu, Zhexiong Wei, Victor Leung Recently, there are growing interests in cognitive radio vehicular ad hoc networks (CR-VANETs), which is a kind of intelligent cyber-physical systems. In CR-VANETs, there are two main processes: spectrum sensing and data transmission. Although some excellent works have been done to address spectrum sensing security and data transmission security in CR-MANETs, these two important areas have traditionally been addressed separately in the literature. In this paper, we propose to use a common framework to study trust management so as to enhance security for both spectrum sensing and data transmission processes in CR-VANETs. We identify a new attack, named joint spectrum sensing and data transmission (JSSDT) attack, in which an attacker can report fake sensing data in the spectrum sensing process as well as drop packets in the data transmission process. Then, using recent advances in the theory of uncertain reasoning, we propose a unified trust management scheme for both spectrum sensing and data transmission processes in CR-VANETs. In addition, based on the unified trust model, we present a weighted consensus-based spectrum sensing scheme to protect the spectrum sensing process. Moreover, we apply the trust value derived from the unified trust model to enhance the security of the data transmission process in CR-VANETs. Simulation results show the effectiveness of the proposed trust-based security schemes.
  • A hierarchical fractional LMS prediction method for data reduction in a
           wireless sensor network
    • Abstract: Publication date: Available online 22 November 2018Source: Ad Hoc NetworksAuthor(s): Pramod Ganjewar, S. Barani, Sanjeev J. Wagh A network of sensor nodes forms WSN, where the nodes observe the environment and transfer the sensed data to the sink node. Constraints on various resources, like energy, bandwidth, and memory, are usual in WSN, which the researchers attempt to solve. This paper presents a transmission technique with data reduction using Hierarchical Fractional Least-Mean-Square (HFLMS), in WSN. The proposed HFLMS filter is a prediction method that attempts to predict the sensed data based on an error estimate. The filter design of HFLMS extends Hierarchical Least-Mean-Square (HLMS) by modifying its weight update using Fractional Calculus (FC). The proposed adaptive filter reduces energy constraints in WSN by allowing the sensor nodes to transmit only the required data to the sink. Thus, HFLMS with integrated FC prolongs the lifespan of the network preserving the energy. Two evaluation parameters, energy and prediction error, are utilized to measure the performance of the algorithm. The experimental results performed using two datasets from UCI machine learning, show that HFLMS has better results than the existing without prediction, LMS, and HLMS techniques, with the energy of 0.1202 at 500th round and minimum prediction error of 0.0253.
  • A Novel Communication Paradigm for High Capacity and Security via
           Programmable Indoor Wireless Environments in Next Generation Wireless
    • Abstract: Publication date: Available online 3 November 2018Source: Ad Hoc NetworksAuthor(s): Christos Liaskos, Shuai Nie, Ageliki Tsioliaridou, Andreas Pitsillides, Sotiris Ioannidis, Ian Akyildiz Wireless communication environments comprise passive objects that cause performance degradation and eavesdropping concerns due to anomalous scattering. This paper proposes a new paradigm, where scattering becomes software-defined and, subsequently, optimizable across wide frequency ranges. Through the proposed programmable wireless environments, the path loss, multi-path fading and interference effects can be controlled and mitigated. Moreover, the eavesdropping can be prevented via novel physical layer security capabilites. The core technology of this new paradigm is the concept of metasurfaces, which are planar intelligent structures whose effects on impinging electromagnetic waves are fully defined by their micro-structure. Their control over impinging waves has been demonstrated to span from 1 GHz to 10 THz. This paper contributes the software-programmable wireless environment, consisting of several HyperSurface tiles (programmable metasurfaces) controlled by a central server. HyperSurfaces are a novel class of metasurfaces whose structure and, hence, electromagnetic behavior can be altered and controlled via a software interface. Multiple networked tiles coat indoor objects, allowing fine-grained, customizable reflection, absorption or polarization overall. A central server calculates and deploys the optimal electromagnetic interaction per tile, to the benefit of communicating devices. Realistic simulations using full 3D ray-tracing demonstrate the groundbreaking performance and security potential of the proposed approach in 2.4 GHz and 60 GHz frequencies.
  • Seamless roaming and guaranteed communication using a synchronized
           single-hop multi-gateway 802.15.4e TSCH network
    • Abstract: Publication date: Available online 31 October 2018Source: Ad Hoc NetworksAuthor(s): Jetmir Haxhibeqiri, Abdulkadir Karaagac, Ingrid Moerman, Jeroen Hoebeke Industrial wireless sensor and actuator networks (WSANs) are being used to improve the efficiency, productivity and safety of industrial processes. One open standard that is commonly used in such cases is IEEE 802.15.4e. Its Time-Slotted Channel Hopping (TSCH) mode employs a time synchronized based medium access control (MAC) scheme together with channel hopping to alleviate the impact of channel fading and interference. Until now, most of the industrial WSANs have been designed to only support static nodes and are not able to deal with mobility. In this paper, we show how a single-hop, multi-gateway IEEE 802.15.4e TSCH network architecture can tackle the mobility problem. We introduce the Virtual Grand Master (VGM) concept that moves the synchronization point from separated Backbone Border Routers (BBRs) towards the backbone network. With time synchronization of all BBRs, mobile nodes can roam from one BBR to another without time desynchronization. In addition to time synchronization, we introduce a mechanism to synchronize the schedules between BBRs to support fast handover of mobile nodes. We show that with the proposed network architecture handovers happen instantly without any packet losses, while the handover time can be up to tens of seconds without any time synchronization between BBRs. The solution is evaluated in a testbed setting as well as in a real industrial environment.
  • An adaptive energy aware strategy based on game theory to add privacy in
           the physical layer for Cognitive WSNs
    • Abstract: Publication date: Available online 27 October 2018Source: Ad Hoc NetworksAuthor(s): Elena Romero, Javier Blesa, Alvaro Araujo The expansion of big data and the evolution of Internet of Things (IoT) technologies will play an important role in the feasibility of Smart City initiatives. In this IoT network infrastructure Cognitive Wireless Sensor Networks (WSNs), as a network of nodes that work in a cooperative way to sense the spectrum and control the environment surrounding them, are one of the main technologies. Security and privacy appear as key aspects for the development of new applications and services. In this work we propose a novel artificial noise generation strategy based on game theory in order to improve the security against privacy attacks in CWSNs. Artificial noise generation consists in introducing interferences in the spectrum in order to mask the real information. The decision whether or not to introduce artificial noise is modeled through a light non-cooperative game designed for low-resources networks that balance security enhancement and energy consumption. We show, using several simulations, that even with a cognitive attacker our strategy has reduced the information obtained by the attacker (Secrecy Outage Probability) to a value under 10%. The overhead (energy consumption and spectrum occupancy) of the strategy has also been deeply analyzed. All possible cases our approach provides better results, in the ratio energy consumption - security, than not using the strategy or using a random noise generation strategy. Also, although the saturation of the radio spectrum is strongly affected, the reliability of the network is maintained in 95% of application packages received. Therefore, we can conclude that an improvement of the privacy in the physical layer is obtained, taking into account energy consumption and maintaining levels of spectrum saturation suitable for the application proposes.
  • Efficient Certificate Revocation Management Schemes for IoT-based Advanced
           Metering Infrastructures in Smart Cities
    • Abstract: Publication date: Available online 27 October 2018Source: Ad Hoc NetworksAuthor(s): Mumin Cebe, Kemal Akkaya Advanced Metering Infrastructure (AMI), which refers to the communication network for the collection of power data from smart meters in a Smart Grid, is expected to be used in the service of many Smart City applications such as gas and water data collection or electric vehicle charging. As the communication within the AMI needs to be secure to protect user’s power data, key management becomes a challenge due to its overhead and limited resources on smart meters. While using public-keys eliminate some of the overhead of key management as opposed to symmetric-key management, there are still challenges regarding the management of certificates that store and certify the public-keys. In particular, distribution and storage of certificate revocation list (CRL) is major a challenge due to cost of distribution and storage in AMI networks which is envisioned to utilize wireless mesh networks. Motivated by the need of keeping the CRL distribution and storage cost effective and scalable, in this paper, we present a distributed CRL management scheme by utilizing distributed hash trees (DHTs) that have been heavily employed in peer-to-peer (P2P) networks. The basic idea is to share the burden of storage of CRLs among all the smart meters by exploiting the convenient wireless communication capability of the smart meters among each other. Using DHTs not only reduces the space requirements for CRLs but also makes the CRL updates more convenient. We implemented DHT-based CRL structure both on ns-3 and testbed using IEEE 802.11s mesh standard as a model for AMI and demonstrated its superior performance with respect to traditional methods of CRL management through extensive simulations.
  • Cost-Aware Securing of IoT Systems Using Attack Graphs
    • Abstract: Publication date: Available online 25 October 2018Source: Ad Hoc NetworksAuthor(s): Beytüllah Yiğit, Gürkan Gür, Fatih Alagöz, Bernhard Tellenbach The Internet of Things (IoT) contains a diverse set of sensors, actuators and other Internet-connected devices communicating, processing data and performing a multitude of functions. It is emerging as an integral part of societal infrastructure enabling smart services. However, these connected objects might have various vulnerabilities that can lead to serious security compromises and breaches. Securing and hardening of IoT systems is thus of vital importance. In that regard, attack graphs provide analytical support to prevent multistep network attacks by showing all possible sequences of vulnerabilities and their interactions. Since attack graphs generally consist of a very large number of nodes, it is computationally challenging to analyze them for network hardening. In this paper, we propose a greedy algorithm using compact attack graphs to find a cost-effective solution to protect IoT systems. First, we extract all possible attack paths which reach predetermined critical resources embedded in the network. Then, exploit or initial condition with minimum effective cost is selected to be removed. This cost is calculated as a function of contribution to attack paths (the higher, the better) and removal cost (the lower, the better). This process continues iteratively until the total cost exceeds the allocated budget. The experimental results show that our algorithm scales almost linearly with the network size and it can be applied to large-scale graphs with a very large number of IoT nodes. In addition to network-hardening, our proposal measures the security level of the network in every step to demonstrate the vulnerability grade of the system.
  • Information Freshness over a Markov Channel: The Effect of Channel State
    • Abstract: Publication date: Available online 24 October 2018Source: Ad Hoc NetworksAuthor(s): Gam D. Nguyen, Sastry Kompella, Clement Kam, Jeffrey E. Wieselthier We consider a communication problem in which a source desires to maintain the freshness of the information updates it sends to a destination, over a channel that varies according to a Markov chain. Freshness is quantified in terms of the age metric (unlike the familiar delay metric), which refers to the difference between the current time and the time of generation of the most recently received update. We then address the impact of channel state information (CSI) on information freshness. Using CSI, transmissions can be adapted to current channel conditions to improve system performance. The following cases are considered: unknown CSI, perfect CSI, erroneous CSI, and delayed CSI.
  • Age of Information with Network Coding
    • Abstract: Publication date: Available online 17 October 2018Source: Ad Hoc NetworksAuthor(s): Maice Costa, Yalin E. Sagduyu We consider the timeliness in delivering a file containing a fixed number of packets through a multicast wireless network using network coding, which is known to improve throughput and reliability for multicast communications. Information timeliness is characterized by metrics related to the Age of Information (AoI). We investigate the impact of network parameters on the average AoI and the peak AoI, including the effect of the number of packets in a coding block, number of destinations, and the Galois field size used for packet encoding. With respect to the field size, the common assumption of an infinite field yields a lower bound on the time to deliver the file to all destinations, but the assumption is impractical. We characterize the AoI for a finite field and show that a large field size may be unnecessary, as the AoI decreases sharply with this parameter. Finally, we consider randomness in obtaining the packets before transmission, including queuing delays in our analysis, and show that optimizing AoI is not equivalent to minimizing delay, and there exists interesting trade-offs among network performance objectives.
  • Analysis and Evaluation of Adaptive RSSI-based Ranging in Outdoor Wireless
           Sensor Networks
    • Abstract: Publication date: Available online 11 October 2018Source: Ad Hoc NetworksAuthor(s): Jari Luomala, Ismo Hakala Estimating inter-node distances based on received radio signal strength (RSSI) is the foundation of RSSI-based outdoor localization in wireless sensor networks (WSNs). However, the accuracy of RSSI-based ranging depends on environmental and weather conditions. Therefore, it is important that RSSI-based ranging adapts to prevailing conditions to improve its range and location accuracy. This paper analyzes and evaluates RSSI-based ranging and adaptive techniques in outdoor WSNs to improve the range quality. The findings highlight the effects of path loss exponent (PLE) estimation error and temperature change on RSSI-based ranging. Consequently, we analyze techniques for mitigating these detrimental effects and propose an adaptive RSSI-based ranging algorithm in order to improve the ranging quality in changing outdoor conditions. The algorithm comprises link RSSI estimation, temperature compensation, PLE estimation, and inter-node distance estimation. Furthermore, we evaluate the performance of the proposed algorithm and compare different WSN-specific PLE estimation techniques by employing real measurement data of 2.4 GHz IEEE 802.15.4-compliant WSN nodes. The results indicate that although ranging error can be mitigated using the proposed adaptive techniques, the accuracy when a single PLE estimate is used is, in general, limited due to high inter-link PLE variation.
  • DoS-resilient Cooperative Beacon Verification for Vehicular Communication
    • Abstract: Publication date: Available online 2 October 2018Source: Ad Hoc NetworksAuthor(s): Hongyu Jin, Panos Papadimitratos Authenticated safety beacons in Vehicular Communication (VC) systems ensure awareness among neighboring vehicles. However, the verification of beacon signatures introduces significant processing overhead for resource-constrained vehicular On-Board Units (OBUs). Even worse in dense neighborhood or when a clogging Denial of Service (DoS) attack is mounted. The OBU would fail to verify for all received (authentic or fictitious) beacons. This could significantly delay the verifications of authentic beacons or even affect the awareness of neighboring vehicle status. In this paper, we propose an efficient cooperative beacon verification scheme leveraging efficient symmetric key based authentication on top of pseudonymous authentication (based on traditional public key cryptography), providing efficient discovery of authentic beacons among a pool of received authentic and fictitious beacons, and can significantly decrease waiting times of beacons in queue before their validations. We show with simulation results that our scheme can guarantee low waiting times for received beacons even in high neighbor density situations and under DoS attacks, under which a traditional scheme would not be workable.
  • Dronemap Planner: A Service-Oriented Cloud-Based Management System for the
    • Abstract: Publication date: Available online 20 September 2018Source: Ad Hoc NetworksAuthor(s): Anis Koubâa, Basit Qureshi, Mohamed-Foued Sriti, Azza Allouch, Yasir Javed, Maram Alajlan, Omar Cheikhrouhou, Mohamed Khalgui, Eduardo Tovar 1 Low-cost Unmanned Aerial Vehicles (UAVs), also known as drones, are increasingly gaining interest for enabling novel commercial and civil Internet-of-Things (IoT) applications. However, there are still open challenges that restrain their real-world deployment. First, drones typically have limited wireless communication ranges with the ground stations preventing their control over large distances. Second, these low-cost aerial platforms have limited computation and energy resources preventing them from running heavy applications onboard. In this paper, we address this gap and we present Dronemap Planner (DP), a service-oriented cloud-based drone management system that controls, monitors and communicates with drones over the Internet. DP allows seamless communication with the drones over the Internet, which enables their control anywhere and anytime without restriction on distance. In addition, DP provides access to cloud computing resources for drones to offload heavy computations. It virtualizes the access to drones through Web services (SOAP and REST), schedules their missions, and promotes collaboration between drones. DP supports two communication protocols: (i.) the MAVLink protocol, which is a lightweight message marshaling protocol supported by commodities Ardupilot-based drones. (ii.) the ROSLink protocol, which is a communication protocol that we developed to integrate Robot Operating System (ROS)-enabled robots into the IoT. We present several applications and proof-of-concepts that were developed using DP. We demonstrate the effectiveness of DP through a performance evaluation study using a real drone for a real-time tracking application.
  • Energy Efficient Cross-layer Approach for Object Security of CoAP for IoT
    • Abstract: Publication date: Available online 10 September 2018Source: Ad Hoc NetworksAuthor(s): Rizwan Hamid Randhawa, Abdul Hameed, Adnan Noor Mian CoAP is an application layer protocol designed for resource-constrained devices in Internet-of-Things (IoT). Object Security of CoAP (OSCoAP) is an IETF draft for addressing security issues with CoAP messages that can arise with the use of intermediate proxies. These proxies are employed for better performance, scalability and offloading expensive operations. OSCoAP adopts the counter with cipher block chaining message authentication code (CCM) mode of authenticated encryption with associated data (AEAD) that simultaneously ensures confidentiality, integrity, and authentication of the messages. The current implementation of CCM for OSCoAP is carried out in software. In this paper, we propose a cross-layer approach towards exploiting the CCM for OSCoAP using mac-layer security suite in IoT devices. The motivation is based on the fact that most of these devices are equipped with 802.15.4 radio chips. The IEEE 802.15.4 standard mandates the availability of some security features for mac-layer encryption in these radio chips including the CCM. We propose an algorithm that takes advantage of these on-board features by efficiently implementing the CCM operations for OSCoAP. The results show that our implementation of CCM is memory efficient, save up to 10 times more energy, improves battery life by 30% and is 37% faster than state of the art software implementation of CCM for OSCoAP.
  • A Secure and Robust Scheme for Sharing Confidential Information in IoT
    • Abstract: Publication date: Available online 10 September 2018Source: Ad Hoc NetworksAuthor(s): Lake Bu, Mihailo Isakov, Michel A. Kinsy In Internet of Things (IoT) systems with security demands, there is often a need to distribute sensitive information (such as encryption keys, digital signatures, or login credentials etc.) to the devices, so that it can be retrieved for confidential purposes at a later moment. However, this piece of information cannot be entrusted to any individual device, since the malfunction of one device will jeopardize the security of the entire network. Even if the information is split among the devices, there is still a danger when attackers compromise a group of them. Therefore we have designed and implemented a secure and robust scheme to facilitate the sharing of sensitive information in IoT networks. This solution provides two important features: 1) This scheme uses Threshold Secret Sharing (TSS) to split the information into shares to be kept by all devices in the system. And so the information can only be retrieved collaboratively by groups of devices. 2) This scheme ensures the privacy and integrity of that piece of information even when there is a large amount of sophisticated and collusive attackers who can hijack the devices. It is able to identify all the compromised devices, while still keeping the secret unknown and unforgeable to attackers.
  • Network Intrusion Detection System for UAV Ad-hoc Communication From
           methodology design to real test validation
    • Abstract: Publication date: Available online 7 September 2018Source: Ad Hoc NetworksAuthor(s): Jean-Philippe Condomines, Ruohao Zhang, Nicolas Larrieu The use of a swarm of low-cost, mission-specific drones to form a Flying Ad-hoc Network (FANET) has literally become a ’hotspot’ in the drone community. A number of studies have been conducted on how to achieve a FANET, but few have considered the security perspectives of this subject. FANET’s unique features have made it difficult to strengthen its defense against ever-changing security threats. Today, more and more FANET applications are implemented into civil airspace, but the development of FANET security has remained unsatisfactory. In this paper, we try to address this issue by proposing a new Intrusion Detection System (IDS), an hybrid method based on both spectral traffic analysis and a robust controller / observer for anomaly estimation inside UAV networks. The proposed hybrid method considers, as a preliminary step, a statistical signature of the traffic exchanged in the network. By examining the resulted signatures, the differences are used to select the accurate model for accurate estimation of that abnormal traffic. The proposed IDS design has been successfully applied to some relevant practical problems such as ad hoc networks for aerial vehicles, and the effectiveness is illustrated by using real traffic traces including Distributed Denial of Service (DDoS) attacks. Our first results show promising perspectives for Intrusion Detection System (IDS) in UAV communication networks. Indeed, different types of anomaly have been considered and they are all accurately detected by the intrusion detection process we propose in this paper. Finally, both simulation-based validation and real-time real-world based implementation of our IDS are described in this article.
  • Neuro-Dominating Set Scheme for a Fast and Efficient Robot Deployment in
           Internet of Robotic Things
    • Abstract: Publication date: Available online 30 August 2018Source: Ad Hoc NetworksAuthor(s): Cristanel Razafimandimby, Valeria Loscrí, Anna Maria Vegni, Abderrahim Benslimane Internet of Robotic Things (IoRT) is a new concept introduced for the first time by ABI Research. Unlike the Internet of Things (IoT), IoRT provides an active sensorization and is considered as the new evolution of IoT. In this context, we propose a Neuro-Dominating Set algorithm (NDS) to efficiently deploy a team of mobile wireless robots in an IoRT scenario, in order to reach a desired inter-robot distance, while maintaining global connectivity in the whole network. We use the term Neuro-Dominating Set to describe our approach, since it is inspired by both neural network and dominating set principles. With NDS algorithm, a robot adopts different behaviors according whether it is a dominating or a dominated robot. Our main goal is to show and demonstrate the beneficial effect of using different behaviors in the IoRT concept. The obtained results show that the proposed method outperforms an existing related technique (i.e., the Virtual Angular Force approach) and the neural network based approach presented in our previous work. As an objective, we aim to decrease the overall traveled distance and keep a low energy consumption level, while maintaining network connectivity and an acceptable convergence time.
  • Efficient DCT-based Secret Key Generation for the Internet of Things
    • Abstract: Publication date: Available online 28 August 2018Source: Ad Hoc NetworksAuthor(s): George Margelis, Xenofon Fafoutis, George Oikonomou, Robert Piechocki, Theo Tryfonas, Paul Thomas Cryptography is one of the most widely employed means to ensure confidentiality in the Internet of Things (IoT). Establishing cryptographically secure links between IoT devices requires the prior consensus to a secret encryption key. Yet, IoT devices are resource-constrained and cannot employ traditional key distribution schemes. As a result, there is a growing interest in generating secret random keys locally, using the shared randomness of the communicating channel. This article presents a secret key generation scheme, named SKYGlow, which is targeted at resource-constrained IoT platforms and tested on devices that employ IEEE 802.15.4 radios. We first examine the practical upper bounds of the number of secret bits that can be extracted from a message exchange. We contrast these upper bounds with the current state-of-the-art, and elaborate on the workings of the proposed scheme. SKYGlow applies the Discrete Cosine Transform (DCT) on channel observations of exchanged messages to reduce mismatches and increase correlation between the generated secret bits. We validate the performance of SKYGlow in both indoor and outdoor scenarios, at 2.4 GHz and 868 MHz respectively. The results suggest that SKYGlow can create secret 128-bit keys of 0.9978 bits entropy with just 65 packet exchanges, outperforming the state-of-the-art in terms of energy efficiency.
  • The Impact of ECDSA in a VANET routing service: Insights from Real Data
    • Abstract: Publication date: Available online 28 August 2018Source: Ad Hoc NetworksAuthor(s): Pedro Cirne, André Zúquete, Susana Sargento, Miguel Luís Both the WAVE IEEE 1609.2 standard in USA and the ETSI ITS security standards in Europe rely on the Elliptic Curve Digital Signature Algorithm (ECDSA) to authenticate messages exchanged among vehicles. Although being faster than other equivalent algorithms, the ECDSA computational cost nevertheless affects the message validation throughput. Even worse, the number of messages that a device has to authenticate may easily exhaust its computational limits.In this article, we evaluated the impact caused by ECDSA authentication of messages of the multi-hop routing control plane used in a real Vehicular Ad Hoc Network (VANET). Such control plane uses periodic vicinity updates to keep accurate, distributed routing paths, and ECDSA-based validation delays may force to discard many of such updates.To perform the evaluation of the impact imposed by ECDSA we considered the multiple curve parameters associated to WAVE and ETSI ITS, their implementation by different cryptographic libraries and their performance in distinct hardware. We took as reference for traffic to be authenticated with ECDSA a day-long set of messages of a VANET routing control plane. These messages were inferred from connectivity status samples from all mobile nodes of a real VANET. Emulation results with those messages show that, without high-end computing devices, ECDSA authentication would have a substantial negative impact in the routing service of the tested VANET.
  • Pairing-based Authentication Protocol for V2G Networks in Smart Grid
    • Abstract: Publication date: Available online 24 August 2018Source: Ad Hoc NetworksAuthor(s): Luis Fernando Arias Roman, Paulo R.L. Gondim, Jaime Lloret Vehicle to Grid (V2G) network is a very important component for Smart Grid (SG), as it offers new services that help the optimization of both supply and demand of energy in the SG network and provide mobile distributed capacity of battery storage for minimizing the dependency of non-renewable energy sources. However, the privacy and anonymity of users’ identity, confidentiality of the transmitted data and location of the Electric Vehicle (EV) must be guaranteed. This article proposes a pairing-based authentication protocol that guarantees confidentiality of communications, protects the identities of EV users and prevents attackers from tracking the vehicle. Results from computing and communications performance analyses were better in comparison to other protocols, thus overcoming signalling congestion and reducing bandwidth consumption. The protocol protects EVs from various known attacks and its formal security analysis revealed it achieves the security goals.
  • Apparatus: A Framework for Security Analysis in Internet of Things Systems
    • Abstract: Publication date: Available online 23 August 2018Source: Ad Hoc NetworksAuthor(s): Orestis Mavropoulos, Haralambos Mouratidis, Andrew Fish, Emmanouil Panaousis Internet of Things (IoT) systems are ubiquitous, highly complex and dynamic event-based systems. These characteristics make their security analysis challenging. Security in IoT requires domain-specific methodologies and tools. The proposed methodologies need to be able to capture information from software and hardware constructs to security and social constructs. In this paper, in addition to refining the modeling language of the Apparatus Framework, we propose a class-based notation of the modeling language and a structured approach to transition between different models. Apparatus is a security framework developed to facilitate security analysis in IoT systems. We demonstrate the application of the framework by analyzing the security of smart public transport system. The security analysis and visualization of the system are facilitated by a software application that is developed as part of the Apparatus Framework.
  • An Efficient Privacy-Preserving Protocol for Database-driven Cognitive
           Radio Networks
    • Abstract: Publication date: Available online 17 August 2018Source: Ad Hoc NetworksAuthor(s): Yali Zeng, Li Xu, Xu Yang, Xun Yi Cognitive radio is regarded as a promising technology for remedying spectrum shortage and improving spectrum utilization. However, database-driven cognitive radio networks (CRNs) are vulnerable to a series of security attacks and privacy threats, especially the privacy breach of secondary users (SUs). In this paper, we propose an efficient privacy-preserving protocol to protect the identity and trajectory privacy of each SU and to prevent the database (DB) from tracing any SU. Besides, this paper also aims at improving the efficiency of authentication and channel allocation to offer the best connectivity to SUs wherever they are and at any time. Taking advantage of the elliptic curve cryptography technique, our protocol achieves the mutual authentication between SUs and base stations (BSs), which enhances the security of CRNs communication. Based on channel pre-allocation to BSs, our protocol reduces the latency of obtaining available channels for SUs. Moreover, our protocol exploits reputation to motivate SUs to be honest and thus increases the utilization of the limited spectrum resources. The results of security analysis show that our protocol provides strong privacy preservation for SUs that the DB cannot get the entire trajectory of any SU, even the DB colludes with all BSs. Furthermore, the results also show that the proposed protocol can resist various types of attacks. The results of performance evaluation indicate the efficiency of the proposed privacy-preserving protocol.
  • On Trust Models for Communication Security in Vehicular Ad-hoc Networks
    • Abstract: Publication date: Available online 17 August 2018Source: Ad Hoc NetworksAuthor(s): Na Fan, Chase Q. Wu Vehicular ad-hoc networks (VANETs) are prone to various network attacks due to its open, dynamic, and distributed nature. It is of increasing importance to assess the trustworthiness of vehicle nodes and messages for communication security in such networks. In this paper, we propose an integrated security scheme to help nodes in VANETs identify the legitimacy of messages for proper decision making. Within the proposed scheme, we first construct trust models to quantify the direct and indirect reputation of a participating node. Particularly, we use the certain-factor model to measure the node’s direct reputation by observing its communication behavior, and synthesize the information from the node’s neighbors and road side unit (RSU) reports to determine its indirect reputation. Both types of reputation are then combined using the uncertain deductive method. Based on these trust models, we further design an attribute-weighted K-means method to identify legitimate messages and a routing method for message delivery in VANETs. We also design and incorporate a dynamic game model-based incentive mechanism to encourage nodes to take cooperative actions and restrain them from selfish behaviors. Extensive simulations show that the proposed security scheme exhibits superior performances over existing methods in alleviating negative effects caused by selfish or malicious nodes.
  • Efficient and Privacy Preserving Supplier Matching for Electric Vehicle
    • Abstract: Publication date: Available online 29 July 2018Source: Ad Hoc NetworksAuthor(s): Fatih Yucel, Kemal Akkaya, Eyuphan Bulut Electric Vehicle (EV) charging takes longer time and happens more frequently compared to refueling of fossil-based vehicles. This requires in-advance scheduling on charging stations depending on the route of the demander EVs for efficient resource allocation. However, such scheduling and frequent charging may leak sensitive information about the users which may expose their driving patterns, whereabouts, schedules, etc. The situation is compounded with the proliferation of EV chargers such as V2V charging where any two EVs can charge each other through a charging cable. In such cases, the matching of these EVs is typically done in a centralized manner which exposes private information to third parties which do the matching. To address this issue, in this paper, we propose an efficient and privacy-preserving distributed matching of demander EVs with charge suppliers (i.e., public/private stations, V2V chargers) using bichromatic mutual nearest neighbor (BMNN) assignments. To this end, we use partially homomorphic encryption-based BMNN computation through local communication (e.g., DSRC or LTE-direct) between users while hiding their locations. The proposed matching algorithm provides not only a satisfactory assignment for all parties but also achieves an efficient matching in dynamic environments where new demanders and suppliers show up and some leave. The simulation results indicate that the proposed matching of suppliers and demanders can be achieved in a distributed fashion within reasonable computation and convergence times while preserving privacy of users. Moreover, due to the nature of its design, it provides a more efficient matching process for dynamic environments compared to standard stable matching algorithm, reducing the average waiting time for users until matching.
  • ACPC: Efficient revocation of pseudonym certificates using activation
    • Abstract: Publication date: Available online 27 July 2018Source: Ad Hoc NetworksAuthor(s): Marcos Vinicius M. Silva, Marcos A. Simplicio, Jefferson E. Ricardini, Eduardo Lopes Cominetti, Harsh Kupwade Patil Vehicular communication (V2X) technologies allow vehicles to exchange information about the road conditions and their own status, and thereby enhance transportation safety and efficiency. For broader deployment, however, such technologies are expected to address security and privacy concerns, preventing abuse by users and by the system’s entities. In particular, the system is expected to enable the revocation of malicious vehicles, e.g., in case they send invalid information to their peers or to the roadside infrastructure; it should also prevent the system from being misused for tracking honest vehicles. Both features are enabled by Vehicular Public Key Infrastructure (VPKI) solutions such as Security Credential Management Systems (SCMS), one of the leading candidates for protecting V2X communication in the United States. Unfortunately, though, SCMS’s original revocation mechanism can lead to large Certification Revocation Lists (CRLs), which in turn impacts the bandwidth usage and processing overhead of the system. In this article, we propose a novel design called Activation Codes for Pseudonym Certificates (ACPC), which can be integrated into SCMS to address this issue. Our proposal is based on activation codes, short bit-strings without which certificates previously issued to a vehicle cannot be used by the latter, which are periodically distributed to non-revoked vehicles using an efficient broadcast mechanism. As a result, the identifiers of the corresponding certificates do no need to remain on the CRL for a long time, reducing the CRLs’ size and streamlining their distribution and verification of any vehicle’s revocation status. Besides describing ACPC in detail, we also compare it to similar-purpose solutions such as Issue First Activate Later (IFAL) and Binary Hash Tree based Certificate Access Management (BCAM). This analysis shows that our proposal not only improves privacy (e.g., in terms of resilience against colluding system authorities), but also leads to processing and bandwidth overheads that are orders of magnitude smaller than those observed in the state of the art.
  • Information Sharing and Bullwhip Effect in Smart Destination Network
    • Abstract: Publication date: Available online 17 July 2018Source: Ad Hoc NetworksAuthor(s): Qijie Jiang, Ge Ke Information communication technologies (ICTs) have been extensively applied in smart destinations in recent years so as to improve the information transfer and information sharing amongst individual actors involving in the destination network ecosystem. This paper attempts to explore the influence of information sharing on the bullwhip effect throughout the tourism supply chain (SC) network, which has been considered as a major problem faces the destination management and all individual actors. Specifically, two mathematic models have been built to analyse the following different situations respectively; first, ICTs have not been well applied in destinations and there is no information sharing amongst individual actors, second, ICTs have been well applied in destinations and there exists information sharing amongst individual actors. Further, this paper makes a comparison of the bullwhip effects under these two situations. What's more, the data collected from JIUZHAI valley has been used to verify the correction of the mathematic analysis. Overall, this paper proves that the application of ICTs will contribute to the reduction of bullwhip effect throughout the tourism SC network by promoting the information sharing amongst individual actors, and some parameters (e.g., autocorrelation coefficient, the number of demand forecasting, and the lead time) will play a crucial role on the acting process. The results have both theoretical significance to the development of tourism SC management theory and managerial implication to tourism practices of individual actors and management departments.
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