Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

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

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Now showing 1 - 6 of 6
  • Article
    Citation - Scopus: 5
    Regional Soft Error Vulnerability and Error Propagation Analysis for Gpgpu Applications
    (Springer, 2022) Öz, I.; Karadaş, Ö.F.
    The wide use of GPUs for general-purpose computations as well as graphics programs makes soft errors a critical concern. Evaluating the soft error vulnerability of GPGPU programs and employing efficient fault tolerance techniques for more reliable execution become more important. Protecting only the most error-sensitive program regions maintains an acceptable reliability level by eliminating the large performance overheads due to redundant operations. Therefore, fine-grained regional soft error vulnerability analysis is crucial for the systems targeting both performance and reliability. In this work, we present a regional fault injection framework and perform a detailed error propagation analysis to evaluate the soft error vulnerability of GPGPU applications. We evaluate both intra-kernel and inter-kernel vulnerabilities for a set of programs and quantify the severity of the data corruptions by considering metrics other than SDC rates. Our experimental study demonstrates that the code regions inside GPGPU programs exhibit different characteristics in terms of soft error vulnerability and the soft errors corrupting the variables propagate into the program output in several ways. We present the potential impact of our analysis by discussing the usage scenarios after we compile our observations acquired from our empirical work. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
  • Conference Object
    Citation - Scopus: 2
    Adaptive Actuator Failure Compensation for Concurrently Actuated Manipulators
    (Elsevier, 2003) Keçeci, Emin Faruk; Tang, Xidong; Tao, Gang
    This paper presents an adaptive actuator failure compensation method, which compensates for uncertainties due to unknown actuator failures and system dynamics, for a class of redundant manipulators where some joints concurrently actuated. Physical realization of concurrently actuated manipulators and their advantageous of use have been understood before, but adaptive failure compensation is still an open issue. In this research, failure formulation, controller structure and adaptive update rules for handling uncertainties from both the system dynamics and the failures are studied. The system stability is shown by a modified Lyapunov. Simulation results show the effectiveness of the proposed adaptive failure compensation control design.
  • Conference Object
    Adaptive Actuator Failure Compensation for Cooperating Multiple Manipulator Systems
    (Elsevier, 2003) Keçeci, Emin Faruk; Tang, Xidong; Tao, Gang
    This paper presents adaptive actuator failure compensation for a cooperating multiple manipulator system with uncertain actuator failures in the task space. Advantages of designing control schemes in task spaces are emphasized, applications of task space control in robotics are discussed and a short review on control algorithms for cooperating multiple manipulator systems is given. Dynamic equations of motion of the multiple manipulator system in the task space are derived, and the adaptive actuator failure compensation problem is formulated. A compensation controller structure is proposed, for which adaptive parameter update laws are developed. The adaptive control scheme is able to compensate for the uncertainties arising from both the system parameters and the actuator failures. Based on Lyapunov stability analysis, the closed-loop signal boundedness and the convergence of the tracking error to zero are ensured. © 2003 International Federation of Automatic Control.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    A User-Assisted Thread-Level Vulnerability Assessment Tool
    (Wiley, 2019) Öz, Işıl; Topçuoğlu, Haluk Rahmi; Tosun, Oğuz
    The system reliability becomes a critical concern in modern architectures with the scale down of circuits. To deal with soft errors, the replication of system resources has been used at both hardware and software levels. Since the redundancy causes performance degradation, it is required to explore partial redundancy techniques that replicate the most vulnerable parts of the code. The redundancy level of user applications depends on user preferences and may be different for the users with different requirements. In this work, we propose a user-assisted reliability assessment tool based on critical thread analysis for redundancy in parallel architectures. Our analysis evaluates the application threads of a parallel program by considering their criticality in the execution and selects the most critical thread or threads to be replicated. Moreover, we extend our analysis by exploring critical regions of individual threads and execute redundantly only those regions to reduce redundancy overhead. Our experimental evaluation indicates that the replication of the most critical thread improves the system reliability more (up to 10% for blackscholes application) than the replication of any other thread. The partial thread replication based on critical region analysis also reduces the vulnerability of the system by considering a fine-grained approach.
  • Conference Object
    Citation - Scopus: 2
    Fault-Tolerance Experiments With a Kinematically Redundant Holonomic Mobile Robot
    (Springer Verlag, 2018) Şahin, Osman Nuri; Çelik, Onur; Dede, Mehmet İsmet Can
    Indoor locomotion with mobile robots has found applications in industrial part moving, factory floor investigation and cleaning tasks. Holonomic mobile robots have the advantage of moving in tight and winding passages without the need of steering. In this study, a four omni-directional wheeled mobile robot is considered. The mobile robot is kinematically redundant having four of these wheels and this is used in providing fault-tolerance due to a malfunction in one of the wheels. In this paper, the redundancy resolution for this mobile robot is explained providing a solution to a fault in one of the wheels during operation. A top level controller to compensate for the orientation errors is introduced. Finally experimental set-up is presented along with the result of the fault-tolerance experiments.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 3
    A Replication-Based Fault Tolerance Protocol Using Group Communication for the Grid
    (Springer Verlag, 2006) Erciyeş, Kayhan
    We describe a replication-based protocol that uses group communication for fault tolerance in the Computational Grid. The Grid is partitioned into a number of clusters and each cluster has a designated coordinator that manages the states of the replicas within its cluster. The coordinators belong to a process group and the proposed protocol ensures the correct sequence of message deliveries to the replicas by the coordinators. Any failing node of the Grid is replaced by an active replica to provide correct continuation of the operation of the application. We show the theoretical framework along with illustrations of the replication protocol and its implementation results and analyze its performance and scalability.