Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Language: search.filters.language.enSubject: search.filters.subject.Fault tolerance

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  • Master Thesis
    Compiler-Managed Fault Tolerance Techniques for General Purpose Graphics Processing Units
    (Izmir Institute of Technology, 2022) Kaya, Ercüment; Öz, Işıl; Öz, Işıl
    As the use of graphics processing units evolves for general-purpose computations besides inherently-fault tolerant graphics programs, soft error reliability becomes a first-class citizen in program design. In this thesis, we aim to increase the reliability of general-purpose graphics processing units. We propose compiler-based redundancy schemes for graphics processing units. Our framework replicates the annotated kernel function by a programmer at compile time. Our selective redundancy approach enables us to provide full redundancy with no error and partial redundancy with an acceptable error rate with higher performance. We develop different schemes to satisfy the performance and memory requirements of the general-purpose graphics processing unit applications. We build our framework on top of the LLVM compiler framework to increase the reliability of applications that exploit the CUDA programming model and evaluate our schemes for the applications from the PolyBench benchmark suite. We reveal that our partial redundancy approach improves the reliability with a small performance overhead and our full redundancy schemes provide complete fault coverage with varying performance differences based on the application's characteristics.
  • Master Thesis
    Redundant Mobile Robort Control
    (Izmir Institute of Technology, 2016) Çelik, Onur; Dede, Mehmet İsmet Can
    Indoor mobile robots are one of the widely researched and developing technologies in robotic field since they can be used in the service robotics and industrial application domains. Moreover, a sub-category of mobile robots, omnidirectional mobile robots, allow performing tasks in narrow indoor spaces by providing better motion capabilities. Additionally, redundancy in mobile robots is started to be used for various advantages including fault tolerance and increased payloads. The objective of this thesis is to improve the design of the omnidirectional mobile robot that was previously constructed in IRL (IzTech Robotics Lab) and develop a redundancy resolution algorithm in order to control the redundant omnidirectional mobile robot to tolerate faults in the actuation system. Initially, the mechanical structure of the mobile robot is improved by the addition of a suspension system for each wheel assembly. A new onboard controller hardware is used and a new top-level controller is employed to be used along the redundancy resolution algorithm. Additionally, previously developed obstacle avoidance algorithm is improved by employing a new configuration of sensors and including a virtual damper to compensate for variable velocity level while approaching to an obstacle. The fault tolerance algorithm is developed in this thesis by integrating a pseudo inverse of the Jacobian matrix that is subjected to a virtual weighted matrix so that the motion of the mobile robot will sustain its motion even though there is an efficiency drop in one of the actuators. Top-level control algorithm along with the fault tolerance and the obstacle avoidance algorithms is experimentally tested and test results indicate that the mobile robot can achieve the primary task in the case of one of the actuator’s efficiency drops down to 70% or in the case of multiple obstacles on the path of the robot.