Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Conference Object
    A Roadmap for Semantifying Recommender Systems Using Preference Management
    (Springer, 2010) Tapucu, Dilek; Tekbacak, Fatih; Ünalır, Murat Osman; Kasap, Seda
    The work developed in this paper presents an innovative solution in the field of recommender systems. Our aim is to create integration architecture for improving recommendation effectiveness that obtains user preferences found implicitly in domain knowledge. This approach is divided into four steps. The first step is based on semantifying domain knowledge. In this step, domain ontology will be analyzed. The second step is to define an innovative hybrid recommendation algorithm based upon collaborative filtering and content filtering. The third step is based on preference modeling approach. And in the fourth step preference model and recommendation algorithm will be integrated. Finally, this work will be realized on Netflix movie data source. © 2011 Springer Science+Business Media B.V.
  • Book Part
    Citation - Scopus: 2
    A Survey on Security in Wireless Sensor Networks: Attacks and Defense Mechanisms
    (IGI Global, 2013) Tekbacak, Fatih; Dalkılıç, Mehmet Emin; Korkmaz, İlker; Dağdeviren, Orhan
    Wireless Sensor Network (WSN) is a promising technology that has attracted the interest of research in the last decade. Security is one of the fundamental issues in sensor networks since sensor nodes are very resource constrained. An attacker may modify, insert, and delete new hardware and software components to the system where a single node, a specific part of the sensing area, and the whole network may become inoperable. Thus, the design of early attack detection and defense mechanisms must be carefully considered. In this chapter, the authors survey attacks and their defense mechanisms in WSNs. Attacks are categorized according to the related protocol layer. They also investigate the open research issues and emerging technologies on security in WSNs.
  • Conference Object
    Citation - Scopus: 1
    A Semantic Based Certification and Access Control Approach Using Security Patterns on Seagent
    (Knowledge Systems Institute, 2008) Tekbacak, Fatih; Tuğlular, Tuğkan; Dikenelli, Oğuz
    In this paper, we propose a security infrastructure for communication between agents adaptable to FIPA security specifications by employing security patterns and semantic based policy descriptions. Security patterns are used as a generalized approach for generating security based services. This paper analyzes the authentication and semantic based access control among agents by using the security patterns.
  • Conference Object
    Citation - Scopus: 1
    Policies for Role Based Agents in Environments With Changing Ontologies
    (International Foundation for Autonomous Agents and Multiagent Systems, 2011) Tekbacak, Fatih; Tuğlular, Tuğkan; Dikenelli, Oğuz
    Software agents try to achieve the goals of roles that they have in an environment. It is supposed that the dynamic structure of role based agents can be connected with updatable domain ontologies of the environment. Ontology evolution can cause the update of agent behaviors or access restrictions to ontological elements. So regulation for the agent behaviors may be needed. Our motivation is to create a suitable policy model for agents, environments and organizations when ontologies in the environment can change.
  • Conference Object
    Citation - Scopus: 5
    Performance Comparison of Combined Collaborative Filtering Algorithms for Recommender Systems
    (Institute of Electrical and Electronics Engineers Inc., 2012) Tapucu, Dilek; Kasap, Seda; Tekbacak, Fatih
    Recommender systems have a goal to make personalized recommendations by using filtering algorithms. Collaborative filtering (CF) is one of the most popular techniques for recommender systems. As usual, huge number of the datasets on the Internet increase the amount of time to work on data. This challenge enforces people to improve better algorithms for processing data with user preferences and recommending the most appropriate item to the users. In this paper, we analyze CF algorithms and present results for combined user-based/item-based CF algorithms for different size of datasets. Our goal is to show combined solution results using Loglikelihood, Spearman, Tanimoto and Pearson algorithms. The contribution is to describe which user based CF algorithms and user/item based combined CF algorithms perform better according to dataset, sparsity, execution time and k-neighborhood values. © 2012 IEEE.
  • Article
    Citation - WoS: 14
    Citation - Scopus: 21
    A Survey of Agent Technologies for Wireless Sensor Networks
    (Medknow Publications and Media, 2011) Dagdeviren, Orhan; Korkmaz, İlker; Tekbacak, Fatih; Erciyeş, Kayhan
    Wireless sensor networks (WSNs) do not have a fixed infrastructure and consist of sensor nodes that perform sensing and communicating tasks. The WSNs have large application spectrum such as habitat monitoring, military surveillance, and target tracking, where sensor nodes may operate distributed in highly dynamic environments. Battery-constrained sensor nodes may aggregate the sensed data, localize themselves, and route the packets in an energy-efficient and decentralized manner to enable running the applications. Agents are capable of independent and autonomous action, so that they can successfully carry out tasks that have been delegated to them, thus agent-based approaches are very suitable to apply as the solution of the problems occurring in WSNs. So far many agent-based approaches were proposed for WSNs. This paper surveys the agent technologies for sensor networks by providing a classification, objectives and costs of these approaches with the open research problems. To the best of our knowledge, this is the first study that covers the intersection of the agent technology and sensor networks from a wide perspective.
  • Conference Object
    Citation - Scopus: 4
    An Architecture for Verification of Access Control Policies With Multi Agent System Ontologies
    (Institute of Electrical and Electronics Engineers Inc., 2009) Tekbacak, Fatih; Tuğlular, Tuğkan; Dikenelli, Oğuz
    Multi-agent systems (MAS) which communicate with intra-domain and inter-domain agent platforms have access control requirements. Instead of a central mechanism, a fine-graned access control mechanism could have been applied to MAS platforms. This paper emphasizes MAS-based domain and security ontologies with XACML-based access control approach for MAS platforms. The domain dependent behaviour and access control parameters in agent ontologies could be combined within a common XACML policy document that is used through different MAS applications. Agent-based access control requirements and common XACML policy documents should be consistent to enforce policies for MAS. To obtain this condition, the translation of organizational policies and platform based policies have to be considered in detail and the verified policy features have to be enforced in MAS to provide access for resources.