23 results on '"Gelenbe, Erol"'
Search Results
2. Randomization of Data Generation Times Improves Performance of Predictive IoT Networks
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Nakıip, Mert and Gelenbe, Erol
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Earliest deadline first scheduling ,Scheduling ,Massive Access Problem ,business.industry ,Computer science ,Test data generation ,Network packet ,Quality of service ,Throughput ,Internet of Things (IoT) ,Predictive networks ,Packet loss ,Logic gate ,Performance improvement ,business ,Computer network - Abstract
Input traffic from Internet of Things (IoT) devices is often both periodic and requires to be received by a given deadline. This can create congestion at instants of time when traffic flowing from multiple devices arrives at a shared input port or gateway, resulting in missed deadlines at the receiver.As a consequence, scheduling techniques such as the “Earliest Deadline First” (EDF) and “Priority based on Average Load” (PAL) are used to schedule the flow from different devices so as to try to satisfy the needs of the largest number of traffic flows in a timely fashion. In this paper, we propose the Randomization of flow Generation Times (RGT) in order to smooth the total incoming traffic to the input port or gateway, on top of the use of EDF and PAL. We then evaluate the performance of RGT together with PAL and EDP, for traffic load with a varyingnumber of up to 6400 IoT devices. Our simulation results show that RGT provides significantly better performance when added to EDF and PAL. Also, the additional computation required by RGT at each device can be quite small, suggesting that RGT is a very useful addition for improving the performance of IoT networks.
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- 2021
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3. Product-Form Solution for Cascade Networks With Intermittent Energy
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Kadioglu Yasin Murat, Gelenbe Erol, and Engineering & Physical Science Research Council (EPSRC)
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Technology ,system workload ,Computer science ,Distributed computing ,0211 other engineering and technologies ,product-form solution ,system performance ,02 engineering and technology ,Energy packet (EP) network ,Job queue ,N-node tandem system ,PFS ,queueing networks ,Engineering ,energy packets (EP) network ,intermittent energy supply ,Throughput (business) ,production lines ,Queueing theory ,Computer Science, Information Systems ,job queue length ,021103 operations research ,Operations Research & Management Science ,Product-form solution ,queueing network models ,Computer Science Applications ,Telecommunications ,Information Systems ,energy harvesting ,Operations Research ,Computer Networks and Communications ,multihop networks ,Supply chain ,power grid ,digital devices ,manufacturing systems ,Energy supply ,Electrical and Electronic Engineering ,cascade networks ,supply chains ,local storage batteries ,intermittent nature ,simultaneous state transitions ,Science & Technology ,product-form solution (PFS) ,Node (networking) ,Engineering, Electrical & Electronic ,digital systems ,possible energy leakage ,Control and Systems Engineering ,Computer Science ,interconnected systems ,Energy (signal processing) - Abstract
The power needs of digital devices, their installation in locations where it is difficult to connect them to the power grid and the difficulty of frequently replacing batteries, create the need to operate digital systems with harvested energy. In such cases, local storage batteries must overcome the intermittent nature of the energy supply. System performance then depends on the intermittent energy supply, possible energy leakage, and system workload. Queueing networks with product-form solution (PFS) are standard tools for analyzing the performance of interconnected systems, and predicting relevant performance metrics including job queue lengths, throughput, and system turnaround times and delays. However, existing queueing network models assume unlimited energy availability, whereas intermittently harvested energy can affect system performance due to insufficient energy supply. Thus, this paper develops a new PFS for the joint probability distribution of energy availability, and job queue length for an N-node tandem system. Such models can represent production lines in manufacturing systems, supply chains, cascaded repeaters for optical links, or a data link with multiple input data ports that feeds into a switch or server. Our result enables the rigorous computation of the relevant performance metrics of such systems operating with intermittent energy.
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- 2019
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4. Steps Toward Self-Aware Networks.
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GELENBE, EROL
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COMPUTER network management , *AUTONOMIC computing , *ELECTRONIC data processing , *COMPUTER network protocols , *QUALITY of service , *COMPUTER science - Abstract
The article discusses the design of self-aware networks (SANs), examining the theoretical and experimental research concerning the technical procedures necessary to establish such networks. SANs are comprised of nodes that can autonomously join and leave a network, as well as discover paths when a need to communicate arises. Other topics of discussion include connections that use paths which optimize the connections own quality of service (QoS) criteria and bio-inspired techniques for networking.
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- 2009
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5. Storms in mobile networks
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Gorbil, Gokce, Abdelrahman, Omer H., Pavloski, Mihajlo, and Gelenbe, Erol
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Networking and Internet Architecture (cs.NI) ,FOS: Computer and information sciences ,Service (systems architecture) ,Computer Science - Cryptography and Security ,business.industry ,Computer science ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,cs.NI ,Botnet ,computer.software_genre ,Radio Resource Control ,Network simulation ,Computer Science - Networking and Internet Architecture ,Signalling ,cs.CR ,Cellular network ,Malware ,business ,Cryptography and Security (cs.CR) ,computer ,Protocol (object-oriented programming) ,Computer network - Abstract
Mobile networks are vulnerable to signalling attacks and storms that are caused by traffic patterns that overload the control plane, and differ from distributed denial of service (DDoS) attacks in the Internet since they directly attack the control plane, and also reserve wireless bandwidth without actually using it. Such attacks can result from malware and mobile botnets, as well as from poorly designed applications, and can cause service outages in 3G and 4G networks which have been experienced by mobile operators. Since the radio resource control (RRC) protocol in 3G and 4G networks is particularly susceptible to such attacks, we analyze their effect with a mathematical model that helps to predict the congestion that is caused by an attack. A detailed simulation model of a mobile network is used to better understand the temporal dynamics of user behavior and signalling in the network and to show how RRC based signalling attacks and storms cause significant problems in the control plane and the user plane of the network. Our analysis also serves to identify how storms can be detected, and to propose how system parameters can be chosen to mitigate their effect., Submitted to the IEEE TETC special issue on "Emerging topics in Cyber Security"
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- 2014
6. Runtime Verification of Component-Based Embedded Software
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Sözer, Hasan, Hofmann, C., Tekinerdogan, B., Aksit, Mehmet, Gelenbe, Erol, Lent, Ricardo, Sakellari, Georgia, Özyeğin University, and Sözer, Hasan
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Computer science ,Component based ,Embedded systems ,Information science ,IR-78300 ,Fault Tolerance ,Runtime behaviors ,EWI-20659 ,Specifications ,Software Architecture ,Component (UML) ,Run-time verification ,Levels of abstraction ,Software system ,METIS-281539 ,Component-based software development ,Software visualization ,Run-time errors ,Error-detection mechanism ,business.industry ,Runtime verification ,Software development ,SE-SA: Software Architecture ,Component-based development ,Embedded software ,Embedded system ,Software construction ,Component-based software engineering ,Working mode ,business ,Embedded Systems - Abstract
Date of Conference: 26-28 September 2011 Conference name: Computer and Information Sciences II - 26th International Symposium on Computer and Information Sciences To deal with increasing size and complexity, component-based software development has been employed in embedded systems. Due to several faults, components can make wrong assumptions about the working mode of the system and the working modes of the other components. To detect mode inconsistencies at runtime, we propose a "lightweight" error detection mechanism, which can be integrated with component-based embedded systems. We define links among three levels of abstractions: the runtime behavior of components, the working mode specifications of components and the specification of the working modes of the system. This allows us to detect the user observable runtime errors. The effectiveness of the approach is demonstrated by implementing a software monitor integrated into a TV system. © 2012 Springer-Verlag London Limited.
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- 2011
7. Support for Resilient Communications in Future Disaster Management
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Jones, Valerie M., Karagiannis, Georgios, Heemstra de Groot, S.M., Gelenbe, Erol, Lent, Ricardo, and Sakellari, Georgia
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Vehicular ad hoc network ,Access network ,BAN ,Emergency management ,Resilience ,Computer science ,business.industry ,Wireless network ,Wireless communications ,EWI-20465 ,MANETS ,QoS ,Communications management ,Critical infrastructure ,Health Monitoring ,GAN ,Wireless ,METIS-279174 ,Vehicular Networks ,Resilience (network) ,business ,Telecommunications ,Disaster Management ,IR-78280 - Abstract
Disasters are often accompanied by damage to critical infrastructure, including (wireless) communications infrastructure. Our solution for emergency communications is based on advanced networks: Generalized Access Networks (GANs), Body Area Networks (BANs) and Vehicular Networks, to support dynamic, resilient communication services for disaster management.
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- 2011
8. Security in Computer and Information Sciences
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Gelenbe, Erol, Campegiani, Paolo, Czachórski, Tadeusz, Katsikas, Sokratis K., Komnios, Ioannis, Romano, Luigi, and Tzovaras, Dimitrios
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Computer science ,Data protection ,Application software ,Data encryption (Computer science) ,Special purpose computers ,Computer communication systems ,thema EDItEUR::G Reference, Information and Interdisciplinary subjects::GP Research and information: general::GPJ Coding theory and cryptology ,thema EDItEUR::U Computing and Information Technology::UK Computer hardware::UKN Network hardware ,thema EDItEUR::U Computing and Information Technology::UN Databases::UNH Information retrieval ,thema EDItEUR::U Computing and Information Technology::UR Computer security ,thema EDItEUR::U Computing and Information Technology::UY Computer science::UYQ Artificial intelligence::UYQE Expert systems / knowledge-based systems - Abstract
This open access book constitutes the thoroughly refereed proceedings of the First International ISCIS Security Workshop 2018, Euro-CYBERSEC 2018, held in London, UK, in February 2018. The 12 full papers presented together with an overview paper were carefully reviewed and selected from 31 submissions. Security of distributed interconnected systems, software systems, and the Internet of Things has become a crucial aspect of the performance of computer systems. The papers deal with these issues, with a specific focus on societally critical systems such as health informatics systems, the Internet of Things, energy systems, digital cities, digital economy, mobile networks, and the underlying physical and network infrastructures.
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- 2018
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9. Comprehensive user requirements engineering methodology for secure and interoperable health data exchange
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Erol Gelenbe, Paolo Campegiani, Luigi Romano, Fabrizio Clemente, Jos Dumortier, Marco Nalin, Evangelos Grivas, Oana Stan, Κostas Votis, Luigi Coppolino, Jan Petersen, Vassilis Koutkias, David Marí, Ioannis Komnios, Maja Voss-Knude, Isaac Cano, Janne Rasmussen, Pantelis Natsiavas, Dimitrios Tzovaras, and Giuliana Faiella
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Process management ,Cybersecurity ,020205 medical informatics ,Computer science ,Interoperability ,02 engineering and technology ,Health informatics ,Internetworking (Telecommunication) ,Workflow ,Gap analysis ,0302 clinical medicine ,Computer security ,Interoperabilitat en xarxes d'ordinadors ,Health care ,0202 electrical engineering, electronic engineering, information engineering ,030212 general & internal medicine ,media_common ,User requirements engineering ,Health Policy ,Data Collection ,3. Good health ,Computer Science Applications ,Europe ,lcsh:R858-859.7 ,Life Sciences & Biomedicine ,Digital health ,Research Article ,Health Informatics ,Seguretat informàtica ,User requirements document ,lcsh:Computer applications to medicine. Medical informatics ,Barriers and facilitators for HIT acceptance ,03 medical and health sciences ,0909 Geomatic Engineering ,media_common.cataloged_instance ,Humans ,European union ,Computer Security ,Digitization ,Science & Technology ,business.industry ,Cross-border health data exchange ,1103 Clinical Sciences ,Scenario ,13. Climate action ,Information security standards ,0806 Information Systems ,Digitalització ,Health information technologies (HIT) ,business ,Medical Informatics - Abstract
Background Increased digitalization of healthcare comes along with the cost of cybercrime proliferation. This results to patients’ and healthcare providers' skepticism to adopt Health Information Technologies (HIT). In Europe, this shortcoming hampers efficient cross-border health data exchange, which requires a holistic, secure and interoperable framework. This study aimed to provide the foundations for designing a secure and interoperable toolkit for cross-border health data exchange within the European Union (EU), conducted in the scope of the KONFIDO project. Particularly, we present our user requirements engineering methodology and the obtained results, driving the technical design of the KONFIDO toolkit. Methods Our methodology relied on four pillars: (a) a gap analysis study, reviewing a range of relevant projects/initiatives, technologies as well as cybersecurity strategies for HIT interoperability and cybersecurity; (b) the definition of user scenarios with major focus on cross-border health data exchange in the three pilot countries of the project; (c) a user requirements elicitation phase containing a threat analysis of the business processes entailed in the user scenarios, and (d) surveying and discussing with key stakeholders, aiming to validate the obtained outcomes and identify barriers and facilitators for HIT adoption linked with cybersecurity and interoperability. Results According to the gap analysis outcomes, full adherence with information security standards is currently not universally met. Sustainability plans shall be defined for adapting existing/evolving frameworks to the state-of-the-art. Overall, lack of integration in a holistic security approach was clearly identified. For each user scenario, we concluded with a comprehensive workflow, highlighting challenges and open issues for their application in our pilot sites. The threat analysis resulted in a set of 30 user goals in total, documented in detail. Finally, indicative barriers of HIT acceptance include lack of awareness regarding HIT risks and legislations, lack of a security-oriented culture and management commitment, as well as usability constraints, while important facilitators concern the adoption of standards and current efforts for a common EU legislation framework. Conclusions Our study provides important insights to address secure and interoperable health data exchange, while our methodological framework constitutes a paradigm for investigating diverse cybersecurity-related risks in the health sector. Electronic supplementary material The online version of this article (10.1186/s12911-018-0664-0) contains supplementary material, which is available to authorized users.
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- 2018
10. The European cross-border health data exchange roadmap: Case study in the Italian setting
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Fabrizio Clemente, Jos Dumortier, Erol Gelenbe, Kostas Votis, Pantelis Natsiavas, Maria Romano, Vassilis Koutkias, Flavia Matrisciano, Ilaria Baroni, Marco Nalin, David Martinez, Giuliana Faiella, Dimitrios Tzovaras, Commission of the European Communities, and European Commission Directorate-General for Research and Innovation
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Technology ,Cybersecurity ,Knowledge management ,cybersecurity ,Regulatory issues ,Interoperability ,Biomedical Engineering ,interoperability ,Health Informatics ,Context (language use) ,Health informatics ,Security information and event management ,03 medical and health sciences ,0302 clinical medicine ,Health care ,eHealth ,Member state ,Electronic Health Records ,Humans ,media_common.cataloged_instance ,European Union ,030212 general & internal medicine ,OPENNCP ,European union ,Computer Security ,11 Medical and Health Sciences ,030304 developmental biology ,media_common ,Ethics ,Travel ,0303 health sciences ,Science & Technology ,regulatory issues ,business.industry ,Cross-border health data exchange ,06 Biological Sciences ,ethics ,3. Good health ,Computer Science Applications ,Italy ,Privacy ,Computer Science ,Computer Science, Interdisciplinary Applications ,08 Information and Computing Sciences ,business ,Life Sciences & Biomedicine ,Medical Informatics - Abstract
Health data exchange is a major challenge due to the sensitive information and the privacy issues entailed. Considering the European context, in which health data must be exchanged between different European Union (EU) Member States, each having a different national regulatory framework as well as different national healthcare structures, the challenge appears even greater. Europe has tried to address this challenge via the epSOS ("Smart Open Services for European Patients") project in 2008, a European large-scale pilot on cross-border sharing of specific health data and services. The adoption of the framework is an ongoing activity, with most Member States planning its implementation by 2020. Yet, this framework is quite generic and leaves a wide space to each EU Member State regarding the definition of roles, processes, workflows and especially the specific integration with the National Infrastructures for eHealth. The aim of this paper is to present the current landscape of the evolving eHealth infrastructure for cross-border health data exchange in Europe, as a result of past and ongoing initiatives, and illustrate challenges, open issues and limitations through a specific case study describing how Italy is approaching its adoption and accommodates the identified barriers. To this end, the paper discusses ethical, regulatory and organizational issues, also focusing on technical aspects, such as interoperability and cybersecurity. Regarding cybersecurity aspects per se, we present the approach of the KONFIDO EU-funded project, which aims to reinforce trust and security in European cross-border health data exchange by leveraging novel approaches and cutting-edge technologies, such as homomorphic encryption, photonic Physical Unclonable Functions (p-PUF), a Security Information and Event Management (SIEM) system, and blockchain-based auditing. In particular, we explain how KONFIDO will test its outcomes through a dedicated pilot based on a realistic scenario, in which Italy is involved in health data exchange with other European countries. ispartof: JOURNAL OF BIOMEDICAL INFORMATICS vol:94 ispartof: location:United States status: published
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- 2019
11. Performance of Selection Hyper-heuristics on the Extended HyFlex Domains
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Warren G. Jackson, Ahmed Kheiri, Alhanof Almutairi, Ender Özcan, Czachórski, Tadeusz, Gelenbe, Erol, Grochla, Krzysztof, and Lent, Ricardo
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Mathematical optimization ,Theoretical computer science ,Computer science ,020207 software engineering ,02 engineering and technology ,Domain (software engineering) ,Set (abstract data type) ,Quadratic equation ,Mixing (mathematics) ,Knapsack problem ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Heuristics ,Metaheuristic ,Selection (genetic algorithm) - Abstract
Selection hyper-heuristics perform search over the space of heuristics by mixing and controlling a predefined set of low level heuristics for solving computationally hard combinatorial optimisation problems. Being reusable methods, they are expected to be applicable to multiple problem domains, hence performing well in cross-domain search. HyFlex is a general purpose heuristic search API which separates the high level search control from the domain details enabling rapid development and performance comparison of heuristic search methods, particularly hyper-heuristics. In this study, the performance of six previously proposed selection hyper-heuristics are evaluated on three recently introduced extended HyFlex problem domains, namely 0–1 Knapsack, Quadratic Assignment and Max-Cut. The empirical results indicate the strong generalising capability of two adaptive selection hyper-heuristics which perform well across the ‘unseen’ problems in addition to the six standard HyFlex problem domains.
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- 2016
12. Occupancy Detection for Building Emergency Management Using BLE Beacons
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William Oliff, George Loukas, Avgoustinos Filippoupolitis, Czachórski, Tadeusz, Gelenbe, Erol, Grochla, Krzysztof, and Lent, Ricardo
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Emergency personnel ,Emergency management ,Occupancy ,business.industry ,Computer science ,computer.internet_protocol ,Real-time computing ,0102 computer and information sciences ,02 engineering and technology ,01 natural sciences ,Emergency situations ,QA76 ,law.invention ,Beacon ,010201 computation theory & mathematics ,law ,Mobile phone ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,business ,computer ,Remote control ,Simulation ,Bluetooth Low Energy - Abstract
Being able to reliable estimate the occupancy of areas inside a building can prove beneficial for managing an emergency situation, as it allows for more efficient allocation of resources such as emergency personnel. In indoor environments, however, occupancy detection can be a very challenging task. A solution to this can be provided by the use of Bluetooth Low Energy (BLE) beacons installed in the building. In this work we evaluate the performance of a BLE based occupancy detection system geared towards emergency situations that take place inside buildings. The system is composed of BLE beacons installed inside the building, a mobile application installed on occupants' mobile phones and a remote control server. Our approach does not require any processing to take place on the occupants' mobile phones, since the occupancy detection is based on a classifier installed on the remote server. Our real-world experiments indicated that the system can provide high classification accuracy for different numbers of installed beacons and occupant movement patterns.
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- 2016
13. A Role and Activity Based Access Control for Secure Healthcare Systems
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Naim Alperen Pulur, Duygu Karaoğlan Altop, Albert Levi, Abdelrahman, Omer H., Gelenbe, Erol, Gorbil, Gökçe, and Lent, Ricardo
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Computer access control ,Computer science ,business.industry ,Medical record ,Internet privacy ,020206 networking & telecommunications ,Context (language use) ,Access control ,02 engineering and technology ,Login ,Computer security ,computer.software_genre ,Order (exchange) ,020204 information systems ,0202 electrical engineering, electronic engineering, information engineering ,Role-based access control ,business ,computer ,Data transmission - Abstract
We introduce a novel access control mechanism in order to safeguard privacy of medical data of patients in dynamic environments. Our access control model takes advantages from role-based access control (RBAC) and criticality aware access control (CAAC). In this way, our original approach allows the medical professionals with different roles to be granted access to medical records of patients automatically and without explicit request in case of a medical emergency. In this context, we design secure and privacy aware protocols from initial login to patients' medical data transmission and retrieval by the medical professionals. Moreover, we formally define access control policies for our system. Finally we show the feasibility of our approach by implementation and performance evaluation.
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- 2015
14. Uneven key pre-distribution scheme for multi-phase wireless sensor networks
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Albert Levi, Onur Catakoglu, Gelenbe, Erol, and Lent, Ricardo
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Scheme (programming language) ,Key distribution in wireless sensor networks ,Multi phase ,Software deployment ,Computer science ,Distributed computing ,Node (networking) ,Key (cryptography) ,computer ,Wireless sensor network ,Pre distribution ,computer.programming_language - Abstract
In multi-phase Wireless Sensor Networks (WSNs), sensor nodes are redeployed periodically to replace nodes whose batteries are depleted. In order to keep the network resilient against node capture attacks across different deployment epochs, called generations, it is necessary to refresh the key pools from which cryptographic keys are distributed. In this paper, we propose Uneven Key Pre-distribution (UKP) scheme that uses multiple different key pools at each generation. Our UKP scheme provides self healing that improves the resiliency of the network at a higher level as compared to an existing scheme in the literature. Moreover, our scheme provides perfect local and global connectivity. We conduct our simulations in mobile environment to see how our scheme performs under more realistic scenarios.
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- 2013
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15. Learning Equilibria in Games by Stochastic Distributed Algorithms
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Johanne Cohen, Olivier Bournez, Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Algorithmique, Combinatoire Analytique et Applications (AlCAAP), Parallélisme, Réseaux, Systèmes, Modélisation (PRISM), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Gelenbe, Erol and Lent, Ricardo, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Bournez, Olivier
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Lyapunov function ,FOS: Computer and information sciences ,[INFO.INFO-CC]Computer Science [cs]/Computational Complexity [cs.CC] ,TheoryofComputation_MISCELLANEOUS ,Computer Science::Computer Science and Game Theory ,Computer science ,Evolutionary game theory ,MathematicsofComputing_NUMERICALANALYSIS ,[SCCO.COMP]Cognitive science/Computer science ,0102 computer and information sciences ,02 engineering and technology ,01 natural sciences ,Machine Learning (cs.LG) ,symbols.namesake ,Computer Science - Computer Science and Game Theory ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,0202 electrical engineering, electronic engineering, information engineering ,Ode ,ComputingMilieux_PERSONALCOMPUTING ,020206 networking & telecommunications ,Computer Science - Learning ,010201 computation theory & mathematics ,Nash equilibrium ,Distributed algorithm ,Ordinary differential equation ,symbols ,[INFO.INFO-CC] Computer Science [cs]/Computational Complexity [cs.CC] ,Martingale (probability theory) ,Mathematical economics ,Congestion game ,Computer Science and Game Theory (cs.GT) - Abstract
We consider a class of fully stochastic and fully distributed algorithms, that we prove to learn equilibria in games. Indeed, we consider a family of stochastic distributed dynamics that we prove to converge weakly (in the sense of weak convergence for probabilistic processes) towards their mean-field limit, i.e an ordinary differential equation (ODE) in the general case. We focus then on a class of stochastic dynamics where this ODE turns out to be related to multipopulation replicator dynamics. Using facts known about convergence of this ODE, we discuss the convergence of the initial stochastic dynamics: For general games, there might be non-convergence, but when convergence of the ODE holds, considered stochastic algorithms converge towards Nash equilibria. For games admitting Lyapunov functions, that we call Lyapunov games, the stochastic dynamics converge. We prove that any ordinal potential game, and hence any potential game is a Lyapunov game, with a multiaffine Lyapunov function. For Lyapunov games with a multiaffine Lyapunov function, we prove that this Lyapunov function is a super-martingale over the stochastic dynamics. This leads a way to provide bounds on their time of convergence by martingale arguments. This applies in particular for many classes of games that have been considered in literature, including several load balancing game scenarios and congestion games.
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- 2013
16. Performance Evaluation of Different CRL Distribution Schemes Embedded in WMN Authentication
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Albert Levi, Ahmet Onur Durahim, İsmail Fatih Yıldırım, Erkay Savas, Gelenbe, Erol, and Lent, Ricardo
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Router ,Task (computing) ,Authentication ,Access network ,Revocation ,Wireless mesh network ,business.industry ,Computer science ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Scalability ,Certification ,business ,Computer network - Abstract
Wireless Mesh Networks (WMNs) have emerged as a promising technology to provide low cost and scalable solutions for high speed Internet access and additional services. In hybrid WMNs, where mesh clients also act as relaying agents and form a mesh client network, it is important to provide users with an efficient anonymous and accountable authentication scheme. Accountability is required for the malicious users that are to be identified and revoked from the network access and related services. Promising revocation schemes are based on Certification Revocation Lists (CRLs). Since in hybrid WMNs mesh clients also authenticate other clients, distribution of these CRLs is an important task. In this paper, we propose and examine the performance of different distribution schemes of CRLs and analyze authentication performance in two scenarios: in one scenario all mesh routers and mesh clients obtain CRLs and in the second one, CRLs are held only by the mesh routers and mesh clients acting as relaying agents require CRL checking to be performed from the router in authenticating another client.
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- 2012
17. A distributed scheme to detect wormhole attacks in mobile wireless sensor networks
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Oya Simsek, Albert Levi, Gelenbe, Erol, Lent, Ricardo, and Sakellari, Georgia
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Scheme (programming language) ,business.industry ,Computer science ,Clock synchronization ,Key distribution in wireless sensor networks ,Mobile wireless sensor network ,False positive rate ,Wormhole ,business ,Focus (optics) ,computer ,Wireless sensor network ,computer.programming_language ,Computer network - Abstract
Due to mostly being unattended, sensor nodes become open to physical attacks such as wormhole attack, which is our focus in this paper. Various solutions are proposed for wormhole attacks in sensor networks, but only a few of them take mobility of sensor nodes into account. We propose a distributed wormhole detection scheme for mobile wireless sensor networks in which mobility of sensor nodes is utilized to estimate two network features (i.e. network node density, standard deviation in network node density) through using neighboring information in a local manner. Wormhole attack is detected via observing anomalies in the neighbor nodes' behaviors based on the estimated network features and the neighboring information. We analyze the performance of proposed scheme via simulations. The results show that our scheme achieves a detection rate up to 100% with very small false positive rate (at most 1.5%) if the system parameters are chosen accordingly. Moreover, our solution requires neither" additional hardware nor tight clock synchronization which are both costly for sensor networks.
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- 2012
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18. Generating Preset Distinguishing Sequences Using SAT
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Uraz Cengiz Türker, Hüsnü Yenigün, Canan Güniçen, Hasan Ural, Gelenbe, Erol, Lent, Ricardo, and Sakellari, Georgia
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QA075 Electronic computers. Computer science ,Sequence ,Finite-state machine ,Computer science ,Computer Science::Computational Complexity ,Computer Science::Robotics ,Computer Science::Multiagent Systems ,Set (abstract data type) ,Brute force ,QA076 Computer software ,Heuristics ,Boolean satisfiability problem ,Algorithm ,Sat problem - Abstract
The preset distinguishing sequence generation problem is converted into a SAT problem to investigate the performance of SAT solvers for generating preset distinguishing sequences. An initial set of experiments are carried out and it is shown that the heuristics of SAT solvers can perform better than brute force algorithms that are used to generate preset distinguishing sequences.
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- 2011
19. Client-based CardSpace-OpenID Interoperation
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Haitham S. Al-Sinani, Chris J. Mitchell, Gelenbe, Erol, Lent, R, and Sakellari, G
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Scheme (programming language) ,business.industry ,Computer science ,Faculty of Science\Mathematics ,Interoperability ,Research Groups and Centres\Information Security\ Information Security Group ,Security token ,Computer security ,computer.software_genre ,Identity management ,Interoperation ,Identity provider ,Identity (object-oriented programming) ,business ,OpenID ,computer ,Computer network ,computer.programming_language - Abstract
We propose a novel scheme to provide interoperability between two of the most widely discussed identity management systems, namely CardSpace and OpenID. In this scheme, CardSpace users are able to obtain an assertion token from an OpenID-enabled identity provider, the contents of which can be processed by a CardSpace-enabled relying party. The scheme, based on a browser extension, is transparent to OpenID providers and to the CardSpace identity selector, and only requires minor changes to the operation of the CardSpace relying party.
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- 2011
20. Modal logics are coalgebraic
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Yde Venema, Lutz Schröder, Corina Cîrstea, Alexander Kurz, Dirk Pattinson, Logic and Computation (ILLC, FNWI/FGw), ILLC (FNWI), Sassone, Vladimiro, Abramsky, Samson, and Gelenbe, Erol
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Theoretical computer science ,General Computer Science ,Knowledge representation and reasoning ,Semantics (computer science) ,Computer science ,Principle of compositionality ,Programming language ,Concurrency ,Modal logic ,computer.software_genre ,Rotation formalisms in three dimensions ,Modal ,Accessibility relation ,computer - Abstract
Applications of modal logics are abundant in computer science, and a large number of structurally different modal logics have been successfully employed in a diverse spectrum of application contexts. Coalgebraic semantics, on the other hand, provides a uniform and encompassing view on the large variety of specific logics used in particular domains. The coalgebraic approach is generic and compositional: tools and techniques simultaneously apply to a large class of application areas and can, moreover, be combined in a modular way. In particular, this facilitates a pick-and-choose approach to domain-specific formalisms, applicable across the entire scope of application areas, leading to generic software tools that are easier to design, to implement and to maintain. This paper substantiates the authors’ firm belief that the systematic exploitation of the coalgebraic nature of modal logic will not only have impact on the field of modal logic itself but also lead to significant progress in a number of areas within computer science, such as knowledge representation and concurrency/mobility.
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- 2011
21. Dependence analysis for regression test suite selection and augmentation
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Hasan Ural, Hüsnü Yenigün, Gelenbe, Erol, Lent, Ricardo, Sakellari, Georgia, Sacan, Ahmet, Toroslu, Hakkı, and Yazıcı, Adnan
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Set (abstract data type) ,QA075 Electronic computers. Computer science ,Test case ,System under test ,Computer science ,Suite ,Extended finite-state machine ,Regression testing ,QA076 Computer software ,Test suite ,Dependence analysis ,Algorithm - Abstract
Using dependence analysis for model-based regression test suite (RTS) selection and augmentation from Extended Finite State Machine (EFSM) representations of system requirements is proposed. Given an EFSM representing the requirements of a system under test (SUT) and a set of modifications (i.e., adding, deleting, and changing transitions) on the EFSM, dependencies between transitions in the EFSM are identified. These dependencies capture the effects of the model on the modifications, the effects of the modifications on the model, and the side-effects of the modifications. The proposed method selects and augments a subset of a given test suite to form an RTS by examining dependencies covered by test cases in the given test suite.
- Published
- 2010
- Full Text
- View/download PDF
22. Developing a Scoring Function for NMR Structure-based Assignments using Machine Learning
- Author
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Bülent Çatay, Hakan Erdogan, Bruce R. Donald, Mehmet Cagri Calpur, Mehmet Serkan Apaydin, Gelenbe, Erol, Lent, Ricardo, Sakellari, Georgia, Sacan, Ahmet, Toroslu, Hakkı, and Yazıcı, Adnan
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Binary integer programming ,Boosting (machine learning) ,Computer science ,business.industry ,Chemical shift ,Residual ,Machine learning ,computer.software_genre ,Nmr data ,Support vector machine ,Residual dipolar coupling ,Structure based ,Artificial intelligence ,business ,computer - Abstract
Nuclear Magnetic Resonance (NMR1) spectroscopy involves the interaction of certain atoms which possess spin property and which are exposed to a combination of a static magnetic field and a second oscillating magnetic field. Determining the assignment of signals received from the experiments (peaks) to specific nuclei of the target molecule in NMR spectroscopy is an important challenge. Nuclear Vector Replacement (NVR) ([2, 3]) is a framework for structure-based assignments which combines multiple types of NMR data such as chemical shifts, residual dipolar couplings, and NOEs. NVR-BIP is a tool which utilizes NVR's data types as well as a scoring function with a binary integer programming (BIP) model to pair NMR peaks and amino acids for protein structure determination. The scoring function of NVR-BIP consists of 7 terms, which are added to obtain the combined score. In this paper, support vector machines (SVM) and boosting are employed to combine the terms in NVR-BIP's scoring function by viewing the assignment as a classification problem. Each peak-residue combination has a ("correct" or "incorrect") label that is predicted and the classification "score" is used as the scoring function for NVR-BIP. The assignment accuracies obtained using this approach show that boosting improves the assignment accuracy of NVR-BIP on our data set when RDCs are not available and outperforms SVMs. With RDCs, boosting and SVMs offer mixed results.
- Published
- 2010
23. PEPA Nets
- Author
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Leïla Kloul, Stephen Gilmore, Jane Hillston, Parallélisme, Réseaux, Systèmes, Modélisation (PRISM), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), M. C. Calzarossa & E. Gelenbe, Moudenner Cohen, Isabelle, Calzarossa, Maria Carla, and Gelenbe, Erol
- Subjects
[INFO.INFO-PF]Computer Science [cs]/Performance [cs.PF] ,Computer science ,[INFO.INFO-PF] Computer Science [cs]/Performance [cs.PF] - Abstract
In this chapter we describe a formalism which uses the stochastic process algebra PEPA as the inscription language for labelled stochastic Petri nets. Viewed in another way, the net is used to provide a structure for linking related PEPA systems. The combined modelling language naturally represents such applications as mobile code systems where the PEPA terms are used to model the program code which moves between network hosts (the places in the net). We demonstrate the modelling capabilities of the formalism on a number of examples, including a mobile server running MobileIP.
- Published
- 2004
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