Computer Engineering / Bilgisayar Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/10

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Author: search.filters.author.Ayav, TolgaPublisher: search.filters.publisher.Institute of Electrical and Electronics Engineers Inc.

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Now showing 1 - 9 of 9
  • Conference Object
    Citation - WoS: 17
    Citation - Scopus: 30
    A Performance and Profit Oriented Data Replication Strategy for Cloud Systems
    (Institute of Electrical and Electronics Engineers Inc., 2017) Tos, Uras; Ayav, Tolga; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, Tolga; Bora, Şebnem; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In today's world, tenants of cloud systems expect timely responses to queries that process ever-increasing sizes of data. However, most cloud providers offer their services without any performance guarantees to their tenants. In this paper we propose a data replication strategy that aims to satisfy performance guarantees for the tenant while ensuring profitability of the cloud provider. Our strategy estimates the response time of the queries, as well as the expenditures that affect the profitability of the cloud provider. The decision of whether to perform replication is determined by the fulfillment of these two criteria. Validity of the proposed strategy is provided by means of a simulation study.
  • Conference Object
    Citation - WoS: 1
    Feedback Control Static Scheduling for Real-Time Distributed Embedded Systems
    (Institute of Electrical and Electronics Engineers Inc., 2005) Ayav, Tolga; Ayav, Tolga; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This paper presents an implementation of feedback control strategy on distributed static scheduling. The static schedule is created taking into account the average execution times of the tasks. Feedback control algorithm handles the unestimated dynamic behaviors in the system and keeps the performance at a desired level. The approach of feedback control supporting static scheduling yields more flexible scheduling, low scheduling overhead and better resource utilization while preserving the realtime constraints.
  • Conference Object
    Citation - Scopus: 2
    Towards Test Case Generation for Synthesizable Vhdl Programs Using Model Checker
    (Institute of Electrical and Electronics Engineers Inc., 2010) Ayav, Tolga; Tuğlular, Tuğkan; Tuğlular, Tuğkan; Ayav, Tolga; Belli, Fevzi; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    VHDL programs are often tested by means of simulations, relying on test benches written intuitively. In this paper, we propose a formal approach to construct test benches from system specification. To consider the real-time properties of VHDL programs, we first transform them to timed automata and then perform model checking against the properties designated from the specification. Counterexamples returned from the model checker serve as a basis of test cases, i.e. they are used to form a test bench. The approach is demonstrated and complemented by a simple case study.
  • Conference Object
    Citation - Scopus: 9
    Adaptive Rtp Rate Control Method
    (Institute of Electrical and Electronics Engineers Inc., 2011) Tos, Uras; Ayav, Tolga; Ayav, Tolga; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this paper, we present an adaptive method for maximizing network bandwidth utilization for the real-time applications. RTP protocol is chosen as the transport protocol and the network utilization is provided by increasing and decreasing the transmission rate of the RTP traffic. Our method employs a PID controller that keeps the RTP packet loss fraction at a predefined reference point. Packet loss fraction parameter is gathered from the RTCP receiver reports and fed into the PID controller that controls the transmission rate of the RTP traffic. Simulations are performed to demonstrate the effectiveness of the method under a bottleneck network configuration with background UDP traffic competing against the RTP traffic for the available bandwidth.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 12
    A Review of Cloud Deployment Models for E-Learning Systems
    (Institute of Electrical and Electronics Engineers Inc., 2013) Leloğlu, Engin; Ayav, Tolga; Aslan, Burak Galip; Ayav, Tolga; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    With the significant growth in the cloud-based systems, many industries give their attention to cloud computing solutions. E-learning is a promising application area since its typical requirements such as dynamically allocation of computation and storage resources, coincide well with cloud characteristics. This paper presents some possible cloud solutions in e-learning environments by emphasizing its pros and cons. It is of paramount importance to choose the most suitable cloud model for an e-learning application or an educational organization in terms of scalability, portability and security. We distinguish various deployment alternatives of cloud computing and discuss their benefits against typical e-learning requirements.
  • Conference Object
    Model Based Testing of Vhdl Programs
    (Institute of Electrical and Electronics Engineers Inc., 2015) Ayav, Tolga; Tuğlular, Tuğkan; Belli, Fevzi; Ayav, Tolga; Tuğlular, Tuğkan; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    VHDL programs are often validated by means of test benches constructed from formal system specification. To include real-time properties of VHDL programs, the proposed approach first transforms them to concurrently running network of timed automata and then performs model checking on properties taken from the specification. Counterexamples generated by the model checker are used to form a test bench. The approach is validated by a case study composed of a nontrivial application running on a microprocessor. As presented, the approach enables testing both hardware and software at once.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 9
    Boolean Differentiation for Formalizing Myers' Cause-Effect Graph Testing Technique
    (Institute of Electrical and Electronics Engineers Inc., 2015) Ayav, Tolga; Belli, Fevzi; Ayav, Tolga; Belli, Fevzi; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Cause-Effect Graph Testing is a popular technique used for almost four decades. Based on Boolean algebra, this technique assists deriving test cases from a given specification informally written in a natural language. The present paper suggests Boolean differentiation for formalizing this technique. The new approach is applied to an example, borrowed from G. Myers, for demonstrating and analyzing its features. Evaluations show that the new approach outperforms Myers' approach in terms of the detected faults per test cases.
  • Conference Object
    Moving Switching Functions To Continuous Domain
    (Institute of Electrical and Electronics Engineers Inc., 2016) Ayav, Tolga; Ayav, Tolga; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This paper proposes a method for moving switching functions to continuous domain. The benefits of this approach are twofold. First, the elementary calculus works with the transformed functions. Second, this transformation approach facilitates various analyses relying on Boolean algebra and other existing Boolean-based calculi like Boolean difference. We present one of the potential applications and show how MCDC test pairs can be computed solely by means of elementary calculus.
  • Conference Object
    Citation - WoS: 26
    Citation - Scopus: 40
    Solving the Course Scheduling Problem Using Simulated Annealing
    (Institute of Electrical and Electronics Engineers Inc., 2009) Aycan, Esra; Ayav, Tolga; Ayav, Tolga; Aycan, Esra; 03.04. Department of Computer Engineering; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This paper tackles the NP-eomplete problem of academic class scheduling (or timetabling). The aim is to find a feasible timetable for the department of computer engineering in Izmir Institute of Technology. The approach focuses on simulated annealing. We compare the performance of various neighborhood searching algorithms based on so-called simple search, swapping, simple search-swapping and their combinations, taking into account the execution times and the final costs. The most satisfactory timetable is achieved with the combination of all these three algorithms. The results highlight the efficacy of the proposed scheme