Athanasios V. Vasilakos

University of Western Macedonia, Kozani, West Macedonia, Greece

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Publications (256)171.54 Total impact

  • Yuezhi Zhou, Yaoxue Zhang, Hao Liu, Naixue Xiong, Athanasios V. Vasilakos
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    ABSTRACT: Advancements in cloud computing enable the easy deployment of numerous services. However, the analysis of cloud service access platforms from a client perspective shows that maintaining and managing clients remain a challenge for end users. In this paper, we present the design, implementation, and evaluation of an asymmetric virtual machine monitor (AVMM), which is an asymmetric partitioning-based bare-metal approach that achieves near-native performance while supporting a new out-of-operating system mechanism for value-added services. To achieve these goals, AVMM divides underlying platforms into two asymmetric partitions: a user partition and a service partition. The user partition runs a commodity user OS, which is assigned to most of the underlying resources, maintaining end-user experience. The service partition runs a specialized OS, which consumes only the needed resources for its tasks and provides enhanced features to the user OS. AVMM considerably reduces virtualization overhead through two approaches: 1) Peripheral devices, such as graphics equipment, are assigned to be monopolized by a single user OS. 2) Efficient resource management mechanisms are leveraged to alleviate complicated resource sharing in existing virtualization technologies. We implement a prototype that supports Windows and Linux systems. Experimental results show that AVMM is a feasible and efficient approach to client virtualization.
    IEEE Transactions on Services Computing 01/2014; 7(1):40-53. · 2.46 Impact Factor
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    ABSTRACT: While resource consolidation enables energy efficiency in virtualized data centers, it results in increased power density and causes excessive heat generation. To prevent servers from overheating and avoid potential damage and/or service outages, data centers need to incorporate temperature awareness in resource provisioning decisions. Moreover, data centers are subject to various peak power constraints (such as peak server power) that have to be satisfied at all times for reliability concerns. In this paper, we propose a novel resource management algorithm, called DREAM (Distributed REsource mAnagement with teMperature constraint), to optimally control the server capacity provisioning (via power adjustment), virtual machine (VM) CPU allocation and load distribution for minimizing the data center power consumption while satisfying the Quality of Service (QoS), IT peak power and maximum server temperature constraints. By using DREAM, each server can autonomously adjust its discrete processing speed (and hence, power consumption, too), and optimally decide the VM CPU allocation as well as amount of workloads to process in the hosted VMs, in order to minimize the total power consumption which incorporates both server power and cooling power. We formally prove that DREAM can yield the minimum power with an arbitrarily high probability while satisfying the peak power and server temperature constraints. To complement the analysis, we perform a simulation study and show that DREAM can significantly reduce the power consumption compared to the optimal temperature-unaware algorithm (by up to 33%) and equal load distribution (by up to 86%).
    Sustainable Computing: Informatics and Systems. 01/2014;
  • Giovanni Acampora, Witold Pedrycz, Athanasios V. Vasilakos
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    ABSTRACT: This paper introduces a novel neuro-fuzzy approach for learning and modeling so-called Multi-Input, Multi-Output Coupling (MIMO) systems, i.e., systems where the output variables may depend upon all systemʼs input variables. This strong coupling makes the MIMO systems behavior highly oscillatory in time and, as a consequence, it makes these systems not particularly suitable to be learned and represented by using conventional approaches. In order to address this issue, our proposal presents an adaptive supervised learning algorithm capable of forming a suitable collection of Timed Automata based Fuzzy Systems that model the dynamic behavior of a given MIMO system. The adaptive learning is accomplished by taking advantage of the theories coming from the area of times series analysis (such as the Adaptive Piecewise Constant Approximation method) with a well-known neuro-fuzzy framework of the Adaptive Neuro Fuzzy Inference System (ANFIS). In experiments, where our proposal has been tested on the Fuzz-IEEE 2011 Fuzzy Competition dataset, the proposed supervised learning algorithm significantly reduces the output error measure and achieves better performance than the one provided by a conventional application of the ANFIS algorithm.
    International Journal of Approximate Reasoning 01/2014; · 1.73 Impact Factor
  • Haomin Yang, Yaoxue Zhang, Yuezhi Zhou, Xiaoming Fu, Hao Liu, Athanasios V. Vasilakos
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    ABSTRACT: Authenticated key agreement protocol is a useful cryptographic primitive, which can be used to protect the confidentiality, integrity and authenticity for transmitted data over insecure networks. From the point of view of the management of pre-shared secrets, one of the advantages of three-party authenticated key agreement (3PAKA) protocols is that they are more suitable for use in a network with large numbers of users compared with two-party authenticated key agreement protocols. Using smart cards is a practical, secure measure to protect the secret private keys of a user. Recently, some 3PAKA protocols using smart cards have been proposed. However, up to now, it is still a challenging problem to propose a 3PAKA protocol using smart cards with fewer rounds of messages and without using timestamp technique. Another important fact to be mentioned is that existing 3PAKA protocols using smart cards all lack provable-security guarantees. In this paper, we propose a new 3PAKA protocol using smart cards. The proposed protocol gains several advantages over existing related protocols: (1) The protocol is provably secure under the computational Diffie–Hellman assumption in the random oracle model, and hence can resist strong adversaries in network scenarios; (2) The protocol needs fewer rounds of messages, and can enable short communication latency and rapid response; and (3) The protocol is not based on timestamp technique, and does not need the complicated clock synchronization.
    Computer Networks. 01/2014; 58:29–38.
  • Zheng Yan, Peng Zhang, Athanasios V. Vasilakos
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    ABSTRACT: Internet of Things (IoT) is going to create a world where physical objects are seamlessly integrated into information networks in order to provide advanced and intelligent services for human-beings. Trust management plays an important role in IoT for reliable data fusion and mining, qualified services with context-awareness, and enhanced user privacy and information security. It helps people overcome perceptions of uncertainty and risk and engages in user acceptance and consumption on IoT services and applications. However, current literature still lacks a comprehensive study on trust management in IoT. In this paper, we investigate the properties of trust, propose objectives of IoT trust management, and provide a survey on the current literature advances towards trustworthy IoT. Furthermore, we discuss unsolved issues, specify research challenges and indicate future research trends by proposing a research model for holistic trust management in IoT.
    Journal of Network and Computer Applications 01/2014; · 1.47 Impact Factor
  • Miao Peng, Hui Chen, Yang Xiao, Suat Ozdemir, Athanasios V. Vasilakos, Jie Wu
    Journal of Parallel and Distributed Computing 01/2014; · 1.12 Impact Factor
  • David Lopez-Perez, Xiaoli Chu, Athanasios V. Vasilakos, Holger Claussen
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    ABSTRACT: With the introduction of femtocells, cellular networks are moving from the conventional centralized network architecture to a distributed one, where each network cell should make its own radio resource allocation decisions, while providing inter-cell interference mitigation. However, realizing such distributed network architecture is not a trivial task. In this paper, we first introduce a simple self-organization rule, based on minimizing cell transmit power, following which a distributed cellular network is able to converge into an efficient resource reuse pattern. Based on such self-organization rule and taking realistic resource allocation constraints into account, we also propose two novel resource allocation algorithms, being autonomous and coordinated, respectively. Performance of the proposed self-organization rule and resource allocation algorithms are evaluated using system-level simulations, and show that power efficiency is not necessarily in conflict with capacity improvements at the network level. The proposed resource allocation algorithms provide significant performance improvements in terms of user outages and network capacity over cutting-edge resource allocation algorithms proposed in the literature.
    IEEE Journal on Selected Areas in Communications 01/2014; 32(2):333-344. · 3.12 Impact Factor
  • Paulo A. Neves, Joel J. P. C. Rodrigues, Min Chen, Athanasios V. Vasilakos
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    ABSTRACT: Wireless sensor and actuator networks provide a distributed system composed of wirelessly connected smart sensor and actuator nodes, suitable for cost-efficient control applications. An important research challenge is deployment, where features like node auto-configuration, unattended operation, and Internet connectivity are becoming mandatory. Moreover, on off-the-shelf solutions the user typically must be network technology-savvy to take advantage of sensing and actuation services. This paper presents a novel multi-channel architecture for sensor data gathering and actuation, featuring Plug-and-Play like functionality for node attachment and operation, IPv6 at the node level, and dedicated communication semantic protocols—the ZenSens system architecture. The architecture features the sensor/actuator nodes, a personal computer application (SenseLab), a mobile application (SenseLab mobile), and World Wide Web access (WebSensor), presenting the user with a complete sensing and actuation solution. As a result the user can operate the network without technological background, and near-zero configuration. All developed software and firmware are presented, and validated through a series of experiments on real hardware, namely using a test-bed with TelosB motes running ContikiOS.
    Journal of Network and Computer Applications - JNCA. 01/2014;
  • Feng Xia, Li Liu, Jie Li, Jianhua Ma, Athanasios V. Vasilakos
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    ABSTRACT: The widespread proliferation of handheld devices enables mobile carriers to be connected at anytime and anywhere. Meanwhile, the mobility patterns of mobile devices strongly depend on the users' movements, which are closely related to their social relationships and behaviors. Consequently, today's mobile networks are becoming increasingly human centric. This leads to the emergence of a new field which we call socially-aware networking (SAN). One of the major features of SAN is that social awareness becomes indispensable information for the design of networking solutions. This emerging paradigm is applicable to various types of networks (e.g. opportunistic networks, mobile social networks, delay tolerant networks, ad hoc networks, etc) where the users have social relationships and interactions. By exploiting social properties of nodes, SAN can provide better networking support to innovative applications and services. In addition, it facilitates the convergence of human society and cyber physical systems. In this paper, for the first time, to the best of our knowledge, we present a survey of this emerging field. Basic concepts of SAN are introduced. We intend to generalize the widely-used social properties in this regard. The state-of-the-art research on SAN is reviewed with focus on three aspects: routing and forwarding, incentive mechanisms and data dissemination. Some important open issues with respect to mobile social sensing and learning, privacy, node selfishness and scalability are discussed.
  • Giovanni Acampora, Diane J Cook, Parisa Rashidi, Athanasios V Vasilakos
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    ABSTRACT: Ambient Intelligence (AmI) is a new paradigm in information technology aimed at empowering people's capabilities by the means of digital environments that are sensitive, adaptive, and responsive to human needs, habits, gestures, and emotions. This futuristic vision of daily environment will enable innovative human-machine interactions characterized by pervasive, unobtrusive and anticipatory communications. Such innovative interaction paradigms make ambient intelligence technology a suitable candidate for developing various real life solutions, including in the health care domain. This survey will discuss the emergence of ambient intelligence (AmI) techniques in the health care domain, in order to provide the research community with the necessary background. We will examine the infrastructure and technology required for achieving the vision of ambient intelligence, such as smart environments and wearable medical devices. We will summarize of the state of the art artificial intelligence methodologies used for developing AmI system in the health care domain, including various learning techniques (for learning from user interaction), reasoning techniques (for reasoning about users' goals and intensions) and planning techniques (for planning activities and interactions). We will also discuss how AmI technology might support people affected by various physical or mental disabilities or chronic disease. Finally, we will point to some of the successful case studies in the area and we will look at the current and future challenges to draw upon the possible future research paths.
    Proceedings of the IEEE 12/2013; 101(12):2470-2494. · 6.91 Impact Factor
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    ABSTRACT: Delay/disruption tolerant networking (DTN) was developed to enable automated network communications despite the long link delay and frequent link disruptions that generally characterize space communications. The performance of DTN convergence layer adapter (CLA) protocols over asymmetric space communication channels has not yet been comprehensively characterized. In this paper, we present an experimental performance evaluation of DTN CLA protocols for reliable data transport over a space communication infrastructure involving asymmetric channel rates, with particular attention to the recently developed Licklider transmission protocol (LTP) CLA (i.e., LTPCL). The performance of LTPCL is evaluated in comparison with other two reliable CLAs, TCP CLA and a hybrid of TCP CLA and LTPCL, for long-delay cislunar communications in the presence of highly asymmetric channel rates. LTPCL is also evaluated and analyzed in a deep-space communication scenario characterized by a very long link delay and lengthy link disruptions.
    Wireless Networks 11/2013; · 0.74 Impact Factor
  • Xiannuan Liang, Yang Xiao, Suat Ozdemir, Athanasios V. Vasilakos, Hongmei Deng
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    ABSTRACT: To produce ciphertexts, two modes of encryption are applied—block ciphers, which encrypt a fixed size block of plaintext at a time, and stream ciphers, which encrypt stream data, one or more bits at a time. As one of stream ciphers, the cipher feedback (CFB) mode is implemented by a block cipher via multiple stages, and in each stage, 1 bit or a number of bits of plaintext are encrypted at a time. Throughout this paper, the study will focus upon the error performance of the stream-based CFB under two sliding-window protocols, go-back-N and selective-reject, in an error channel in terms of throughput. We model the performance of the CFB in terms of application-level throughput and derive the number of stages needed to achieve the optimal throughput, under a given error rate in an error channel. Copyright © 2012 John Wiley & Sons, Ltd.
    Security and Communication Networks 08/2013; 6(8). · 0.31 Impact Factor
  • Guojun Wang, Jianhua Ma, Athanasios V. Vasilakos
    Journal of Computer and System Sciences 08/2013; 79(5):515–517. · 1.00 Impact Factor
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    Kai Han, Jun Luo, Yang Liu, Athanasios V Vasilakos
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    ABSTRACT: Though duty-cycling has long been a critical mech-anism for energy conservation in wireless sensor networks, it is only recently that research efforts have been put to design data communication protocols that perform efficiently in Duty-Cycled Wireless Sensor Networks (DC-WSNs). In this article, we survey these research problems, aiming at revealing insights into the following three key questions: i) what are the meaningful (algorithm design) problems for DC-WSNs? ii) which problems have been studied and which have not? and iii) what are the essential techniques behind the existing solutions? All these insights may serve as motivations and inspirations for further developments in this field.
    IEEE Communications Magazine 07/2013; 51(7):107-113. · 3.66 Impact Factor
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    Guiyi Wei, Ping Zhu, Athanasios V. Vasilakos, Yuxin Miao, Jun Luo, Yun Ling
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    ABSTRACT: In collaborative social networks (CSNs), autonomous individuals cooperate for their common reciprocity interests. The intrinsic heterogeneity of individuals’ capability and willingness makes significant impact on the promotion of cooperation rate. In this paper, we propose a two-phase Heterogeneous Public Goods Game (HPGG) model to study the cooperation dynamics in CSNs. We introduce two factors to represent the heterogeneity of individual behaviors and the benefit-to-cost enhancement of population, respectively. Based on HPGG CSN model, we quantitatively investigate the relationship between cooperation rate and individuals’ heterogeneous behaviors from an evolutionary game perspective. Simulations on the population structure of scale-free networks show the evolution of cooperation in CSNs has no-trivial dependence on the individuals’ heterogeneous behaviors. Compared with standard PGG and single-phase heterogeneous PGG, HPGG provides a more precise mechanism to promote cooperation rate of CSNs. Finally, data traces collected from real experiments also demonstrate the preciseness of HPGG in formulating the cooperation dynamics on CSNs.
    IEEE Journal on Selected Areas in Communications 06/2013; 31(6):1135-1146. · 3.12 Impact Factor
  • Shengzhi Zhang, Wenjie Wang, Haishan Wu, Athanasios V. Vasilakos, Peng Liu
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    ABSTRACT: The rapid expansion of cloud offerings poses fundamental tasks for workload management in a large scale server farm. In order to achieve satisfactory Quality of Service (QoS) and reduce operation cost, we present a fully distributed workload management system in a large scale server environment, e.g., cloud. Different from existing centralized control approaches, the workload management logic hierarchically spreads on each back-end server and front-end proxy. The control solution is designed to offer both overload protection and resource efficiency for the back-end servers, while achieving service differentiation based on Service Level Agreement (SLA). The proposed system can directly work with legacy software stack, because the implementation requires no changes to the target operating system, application servers, or web applications. Our evaluation shows that it achieves both overload protection and service classification under dynamic heavy workload. Furthermore, it also demonstrates negligible management overhead, satisfactory fault-tolerance and fast convergence.
    Future Generation Computer Systems 06/2013; 29(4):913–925. · 1.86 Impact Factor
  • Yuanyuan Zeng, Deshi Li, Athanasios V. Vasilakos
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    ABSTRACT: Wireless sensor and actuator networks (WSANs) are composed of a large number of heterogeneous sensors and actuators that enable to make reactions toward the physical information sensed. Reactive WSANs are widely used in a range of applications, and some of them are used in delay-sensitive surveillance systems. Compared to sensors, actuators have more capabilities, which can move with self-awareness and then help to fulfill reaction tasks according to application requirements. By taking advantage of mobile actuators, we present a novel framework of real-time data report and task execution (RTRE) for automated WSANs in this paper. The real-time sensor–actuator data collection is achieved through coordination among sensors and mobile actuators. The real-time task execution is achieved through multi-actuator coordination with priority-based multi-event task assignment. The schemes provide energy efficiency with timely reactions. Simulation results are shown to demonstrate the advantage of RTRE when compared with the other related work in terms of timeliness and energy efficiency.
    Computer Communications. 05/2013; 36(9):988–997.
  • Jingtao Yao, Athanasios V Vasilakos, Witold Pedrycz
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    ABSTRACT: Granular computing, as a new and rapidly growing paradigm of information processing, has attracted many researchers and practitioners. Granular computing is an umbrella term to cover any theories, methodologies, techniques, and tools that make use of information granules in complex problem solving. The aim of this paper is to review foundations and schools of research and to elaborate on current developments in granular computing research. We first review some basic notions of granular computing. Classification and descriptions of various schools of research in granular computing are given. We also present and identify some research directions in granular computing.
    IEEE transactions on cybernetics. 03/2013;
  • Long Jin, Yang Chen, Tianyi Wang, Pan Hui, A.V. Vasilakos
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    ABSTRACT: Currently, online social networks such as Facebook, Twitter, Google+, LinkedIn, and Foursquare have become extremely popular all over the world and play a significant role in people¿s daily lives. People access OSNs using both traditional desktop PCs and new emerging mobile devices. With more than one billion users worldwide, OSNs are a new venue of innovation with many challenging research problems. In this survey, we aim to give a comprehensive review of state-of-the-art research related to user behavior in OSNs from several perspectives. First, we discuss social connectivity and interaction among users. Also, we investigate traffic activity from a network perspective. Moreover, as mobile devices become a commodity, we pay attention to the characteristics of social behaviors in mobile environments. Last but not least, we review malicious behaviors of OSN users, and discuss several solutions to detect misbehaving users. Our survey serves the important roles of both providing a systematic exploration of existing research highlights and triggering various potentially significant research in these topics.
    IEEE Communications Magazine 01/2013; 51(9):144-150. · 3.66 Impact Factor
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    ABSTRACT: We propose a distributed and coordinated radio resource allocation algorithm for orthogonal frequency division multiple access (OFDMA)-based cellular networks to self-organize efficient and stable frequency reuse patterns. In the proposed radio resource allocation algorithm, each cell independently and dynamically allocates modulation and coding scheme (MCS), resource block (RB), and transmit power to its users in a way that its total downlink (DL) transmit power is minimized, while users' throughput demands are satisfied. Moreover, each cell informs neighboring cells of the RBs that have been scheduled for its cell-edge users' DL transmissions through message passing. Accordingly, the neighboring cells abstain from assigning high transmit powers to the specified RBs. Extensive simulation results attempt to demonstrate that DL power control on a per-RB basis may play a key role in future networks, and show that the distributed minimization of DL transmit power at each cell, supported by intercell interference coordination, is able to provide a 20% improvement of network throughput, considerably reduce the number of user outages, and significantly enhance spatial reuse, as compared to cutting-edge resource allocation schemes.
    IEEE/ACM Transactions on Networking 01/2013; 21(4):1145-1158. · 2.01 Impact Factor

Publication Stats

680 Citations
171.54 Total Impact Points


  • 2007–2014
    • University of Western Macedonia
      • Department of Engineering Informatics and Telecommunications
      Kozani, West Macedonia, Greece
  • 1997–2014
    • National Technical University of Athens
      • School of Electrical and Computer Engineering
      Athínai, Attica, Greece
  • 2013
    • Kuwait University
      • Department of Computer Science
      Al Kuwayt, Al Asimah Governorate, Kuwait
  • 2012
    • University of Western Greece
      Agrínio, West Greece, Greece
  • 2011
    • Zhejiang Gongshang University
      Hang-hsien, Zhejiang Sheng, China
    • Seoul National University
      • Department of Computer Science and Engineering
      Sŏul, Seoul, South Korea
    • JiangXi University of Finance and Economics
      Nan-ch’ang-shih, Jiangxi Sheng, China
    • Hosei University
      Edo, Tōkyō, Japan
    • University of Science and Technology of China
      • Department of Electronic Engineering and Information Science
      Hefei, Anhui Sheng, China
    • Nantong University
      Tungchow, Jiangsu Sheng, China
    • Universidade da Beira Interior
      • Institute of Telecommunications (IT-UBI)
      Ковильян, Castelo Branco, Portugal
  • 2010
    • Huazhong University of Science and Technology
      • Department of Control Science and Engineering
      Wuhan, Hubei, China
    • London South Bank University
      Londinium, England, United Kingdom
    • Tohoku University
      • Graduate School of Science
      Sendai-shi, Miyagi-ken, Japan
    • Università degli Studi di Salerno
      • Department of Computer Science DI
      Fisciano, Campania, Italy
    • Wright-Patterson Air Force Base
      Dayton, Ohio, United States
    • Paris Dauphine University
      Lutetia Parisorum, Île-de-France, France
  • 2009–2010
    • Peking University
      Peping, Beijing, China
    • Georgia State University
      • Department of Computer Science
      Atlanta, GA, United States
    • Louisiana State University
      • Department of Computer Science
      Baton Rouge, Louisiana, United States
  • 2008–2009
    • Heriot-Watt University
      • School of Engineering and Physical Sciences
      Edinburgh, SCT, United Kingdom
    • University of Glasgow
      Glasgow, Scotland, United Kingdom
  • 2007–2009
    • Central South University
      Ch’ang-sha-shih, Hunan, China
  • 2007–2008
    • University of Peloponnese
      Trípoli, Peloponnese, Greece
  • 2005–2007
    • University of Thessaly
      • Τμήμα Μηχανικών Χωροταξίας Πολεοδομίας και Περιφερειακής Ανάπτυξης
      Iolcus, Thessaly, Greece
  • 2002–2005
    • Hellenic Aerospace Industry
      Athínai, Attica, Greece
  • 2000–2002
    • University of Cyprus
      • Department of Computer Science
      Nicosia, Nicosia District, Cyprus
  • 1999
    • University of Alberta
      • Department of Electrical and Computer Engineering
      Edmonton, Alberta, Canada
  • 1996
    • The Centre for Research and Technology, Hellas
      Saloníki, Central Macedonia, Greece
  • 1994–1996
    • Hellenic Air Force
      Athínai, Attica, Greece
  • 1993
    • University of Patras
      Rhion, West Greece, Greece