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Full-Text Articles in Computer Engineering
Improving The Efficiency Of Dnn Hardware Accelerator By Replacing Digitalfeature Extractor With An Imprecise Neuromorphic Hardware, Majid Mohammadi Rad, Omid Sojodishijani
Improving The Efficiency Of Dnn Hardware Accelerator By Replacing Digitalfeature Extractor With An Imprecise Neuromorphic Hardware, Majid Mohammadi Rad, Omid Sojodishijani
Turkish Journal of Electrical Engineering and Computer Sciences
Mixed-signal in-memory computation can drastically improve the efficiency of the hardware implementing machine learning (ML) algorithms by (i) removing the need to fetch neural network parameters from internal or external memory and (ii) performing a large number of multiply-accumulate operations in parallel. However, this boost in efficiency comes with some disadvantages. Among them, the inability to precisely program nonvolatile memory devices (NVM) with neural network parameters and sensitivity to noise prevent the mixed-signal hardware to perform a precise and deterministic computation. Unfortunately, these hardware-specific errors can get magnified while propagating along with the layers of the deep neural network. In …
Flexibility Of Remediation Methods For Winding Open Circuit Faults In A Multiphase Pm Machine Considering Iron Losses Minimization, Fan Wu, Ayman M. El-Refaie
Flexibility Of Remediation Methods For Winding Open Circuit Faults In A Multiphase Pm Machine Considering Iron Losses Minimization, Fan Wu, Ayman M. El-Refaie
Electrical and Computer Engineering Faculty Research and Publications
The flexibility of post-fault control in multiphase machine systems stems from their multiple degrees of freedom. A post-fault loss-minimization method is proposed and investigated in this paper, in which both the machine copper and iron losses are considered during the derivation of post-fault remediation methods. Therefore, machine efficiency during post-fault operation can be further improved compared to the conventional stator-ohmic-loss-minimization approach. In addition, the combination of three key factors/constraints that can influence the post-fault control strategy of a six-phase permanent magnet (PM) machine has been investigated. By comparing four selected remediation methods based on three constraints, the pros and cons …
Tapu: Test And Pick Up-Based $K$-Connectivity Restoration Algorithm For Wireless Sensor Networks, Vahi̇d Khali̇lpour Akram, Orhan Dağdevi̇ren
Tapu: Test And Pick Up-Based $K$-Connectivity Restoration Algorithm For Wireless Sensor Networks, Vahi̇d Khali̇lpour Akram, Orhan Dağdevi̇ren
Turkish Journal of Electrical Engineering and Computer Sciences
A $k$-connected wireless sensor network remains connected if any $k$-1 arbitrary nodes stop working. The aim of movement-assisted $k$-connectivity restoration is to preserve the $k$-connectivity of a network by moving the nodes to the necessary positions after possible failures in nodes. This paper proposes an algorithm named TAPU for $k$-connectivity restoration that guarantees the optimal movement cost. Our algorithm improves the time and space complexities of the previous approach (MCCR) in both best and worst cases. In the proposed algorithm, the nodes are classified into safe and unsafe groups. Failures of safe nodes do not change the $k$ value of …
A Fault-Tolerant T-Type Multilevel Inverter Topology With Increased Overload Capability And Soft-Switching Characteristics, Jiangbiao He, Ramin Katebi, Nathan Weise, Nabeel Demerdash, Lixiang Wei
A Fault-Tolerant T-Type Multilevel Inverter Topology With Increased Overload Capability And Soft-Switching Characteristics, Jiangbiao He, Ramin Katebi, Nathan Weise, Nabeel Demerdash, Lixiang Wei
Electrical and Computer Engineering Faculty Research and Publications
he performance of a novel three-phase four-leg fault-tolerant T-type inverter topology is introduced in this paper. This inverter topology provides a fault-tolerant solution to any open-circuit and certain short-circuit switching faults in the power devices. During any of the fault-tolerant operation modes for these device faults, there is no derating required in the inverter output voltage or output power. In addition, overload capability is increased in this new T-type inverter compared to that in the conventional three-level T-type inverter. Such increase in inverter overload capability is due to the utilization of the redundant leg for overload current sharing with other …
A Centralized Self-Adaptive Fault Tolerance Approach Based On Feedback Control For Multiagent Systems, Şebnem Bora, Oğuz Di̇kenelli̇
A Centralized Self-Adaptive Fault Tolerance Approach Based On Feedback Control For Multiagent Systems, Şebnem Bora, Oğuz Di̇kenelli̇
Turkish Journal of Electrical Engineering and Computer Sciences
Our research introduces a self-adaptive fault tolerance approach for multiagent systems that enables the system to avoid crash failures. It is a replication-based approach that exploits a feedback control loop and a proportional (P) controller within a replication infrastructure. Thus, we are able to both observe the agents' behaviors to estimate criticalities and determine the number of replicas in replica groups with respect to the agents' criticalities and the number of available resources. Thus, agents that are to be replicated and the numbers of replicas in replica groups are automatically and adaptively identified in dynamic environments. We implement this approach …
Load Management In A Distributed Multimedia Streaming Environment Using A Fault-Tolerant Hierarchical System, Hadi̇ Işik Aybay, Mohammad Ahmed Shah
Load Management In A Distributed Multimedia Streaming Environment Using A Fault-Tolerant Hierarchical System, Hadi̇ Işik Aybay, Mohammad Ahmed Shah
Turkish Journal of Electrical Engineering and Computer Sciences
In contrast to text-only forms of communications, multimedia uses a combination of audiovisual means alongside textual modes of communication. Streaming multimedia is such multimedia that is constantly delivered by a provider of the multimedia to a client. In streaming multimedia the streamed content is continually presented to and received by the end user. Distributed multimedia systems (DMSs) deliver multimedia content to end-users by means of distributed multimedia databases and distributed information servers. These DMSs are designed to deliver multimedia content over a network. A fault-tolerant redundant hierarchy (Red-HI)-based load management policy for a distributed multimedia streaming system is proposed in …
End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith
End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith
Wenbing Zhao
This paper presents an evaluation of the end-to-end latency of a fault-tolerant CORBA infrastructure that we have implemented. The fault-tolerant infrastructure replicates the server applications using active, passive and semi-active replication, and maintains strong replica consistency of the server replicas. By analyses and by measurements of the running fault-tolerant infrastructure, we characterize the end-to-end latency under fault-free conditions. The main determining factor of the run-time performance of the fault-tolerant infrastructure is the Totem group communication protocol, which contributes to the end-to-end latency primarily in two ways: the delay in sending messages and the processing cost of the rotating token. To …
Fault Tolerant Broadcasting Analysis In Wireless Monitoring Networks, Akbar Ghaffarpour Rahbar
Fault Tolerant Broadcasting Analysis In Wireless Monitoring Networks, Akbar Ghaffarpour Rahbar
Turkish Journal of Electrical Engineering and Computer Sciences
Wireless monitoring networks can be used for security applications such as the monitoring of narrow passages and operational fields. These networks can be designed based on sensor networks. In sensor networks, each node can hear a message and broadcast the message to its neighbor nodes. Nevertheless, nodes may fail, so that faulty nodes cannot hear or cannot transmit any message, where the locations of the faulty nodes are unknown and their failures are permanent. In this paper, the nodes are situated on a line or a square grid-based topology in a plane for security/monitoring applications. For each topology, 2 nonadaptive …
Fault-Tolerant Operation Of Delta-Connected Scalar- And Vector-Controlled Ac Motor Drives, Ahmed Mohamed Sayed Ahmed, Nabeel Demerdash
Fault-Tolerant Operation Of Delta-Connected Scalar- And Vector-Controlled Ac Motor Drives, Ahmed Mohamed Sayed Ahmed, Nabeel Demerdash
Electrical and Computer Engineering Faculty Research and Publications
Operation and analysis of delta-connected ac motor-drive systems under fault-tolerant open-phase mode of operation is introduced in this paper for both scalar- and vector-controlled motor-drive systems. This technique enables the operation of the three-phase motor upon a failure in one of its phases without the need of a special fault-detection algorithm. It is mainly used to significantly mitigate torque pulsations, which are caused by an open-delta configuration in the stator windings. The performance of the fault-tolerant system was verified using a detailed time stepping finite element simulation as well experimental tests for a 5-hp 460-V induction motor-drive system and the …
Fault-Tolerant Technique For Δ-Connected Ac-Motor Drives, Ahmed Mohamed Sayed Ahmed, Behrooz Mirafzal, Nabeel Demerdash
Fault-Tolerant Technique For Δ-Connected Ac-Motor Drives, Ahmed Mohamed Sayed Ahmed, Behrooz Mirafzal, Nabeel Demerdash
Electrical and Computer Engineering Faculty Research and Publications
A fault-tolerant technique for motor-drive systems is introduced in this paper. The technique is merely presented for ac motors with Δ-connected circuits in their stator windings. In this technique, the faulty phase is isolated by solid-state switches after the occurrence of a failure in one of the stator phases. Then, the fault-tolerant technique manages current-flow in the remaining healthy phases. This technique is to significantly mitigate torque pulsations, which are caused by an open-Δ configuration in the stator windings. The performance of the fault-tolerant technique was experimentally verified using a 5-hp 460-V induction motor-drive system and the results are presented …
End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith
End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith
Electrical and Computer Engineering Faculty Publications
This paper presents an evaluation of the end-to-end latency of a fault-tolerant CORBA infrastructure that we have implemented. The fault-tolerant infrastructure replicates the server applications using active, passive and semi-active replication, and maintains strong replica consistency of the server replicas. By analyses and by measurements of the running fault-tolerant infrastructure, we characterize the end-to-end latency under fault-free conditions. The main determining factor of the run-time performance of the fault-tolerant infrastructure is the Totem group communication protocol, which contributes to the end-to-end latency primarily in …
Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith
Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith
Electrical and Computer Engineering Faculty Publications
In this paper, we describe a software infrastructure that unifies transactions and replication in three-tier architectures and provides data consistency and high availability for enterprise applications. The infrastructure uses transactions based on the CORBA object transaction service to protect the application data in databases on stable storage, using a roll-backward recovery strategy, and replication based on the fault tolerant CORBA standard to protect the middle-tier servers, using a roll-forward recovery strategy. The infrastructure replicates the middle-tier servers to protect the application business logic processing. In addition, it replicates the transaction coordinator, which renders the two-phase commit protocol nonblocking and, thus, …