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Full-Text Articles in Computer Engineering

On The Performance Analysis Of Flexible Pairing Between Uav And Gu In Noma, Man Hee Lee, Soo Young Shin Jul 2022

On The Performance Analysis Of Flexible Pairing Between Uav And Gu In Noma, Man Hee Lee, Soo Young Shin

Turkish Journal of Electrical Engineering and Computer Sciences

The wireless communications regarding unmanned aerial vehicles (UAVs) have been investigated for the usage of base stations (BS) to provide Internet access. This paper presents the usage of a UAV as a pairing user to enhance the sum capacity by flexible pairing in nonorthogonal multiple access (NOMA). In the proposed scheme, the UAVs and the ground users (GUs) get paired to promote the line-of-sight (LoS) characteristics. The performance of flexible pairing is presented in terms of sum capacity, outage probability, and throughput with the LoS path loss. Channel modeling is necessary to apply flexible pairing by utilizing the LoS characteristic …


Dynamic Issue Queue Capping For Simultaneous Multithreaded Processors, Merve Güney, Büşra Kuru, Sercan Sari, İsa Ahmet Güney, Gürhan Küçük Jan 2021

Dynamic Issue Queue Capping For Simultaneous Multithreaded Processors, Merve Güney, Büşra Kuru, Sercan Sari, İsa Ahmet Güney, Gürhan Küçük

Turkish Journal of Electrical Engineering and Computer Sciences

A simultaneous multithreaded (SMT) processor mixes multiple instruction streams in its superscalar out-of-order execution core for higher throughput. To achieve this, a superscalar processor is modified in such a way that someof its resources are duplicated and the rest is shared among multiple threads. The issue queue (IQ), which holds allwaiting instructions until they become ready and scheduled for execution, is among these shared resources. A baselineunmanaged IQ can give an unexpectedly low performance since a hungry thread can tie up most of the IQ entries.This type of scenario is also worse in terms of the fairness metric since some …


Mobility And Traffic-Aware Resource Scheduling For Downlink Transmissions In Lte-A Systems, Önem Yildiz, Radosveta İvanova Sokullu Jan 2019

Mobility And Traffic-Aware Resource Scheduling For Downlink Transmissions In Lte-A Systems, Önem Yildiz, Radosveta İvanova Sokullu

Turkish Journal of Electrical Engineering and Computer Sciences

As new cellular networks support not only voice services but also many multimedia applications, the requirements for reliable data transmission at high speeds create heavy load on the system. Even though LTE/LTE-A technology takes action towards alleviating this load, it is still necessary to manage resources effectively because of the inadequacy of the available radio resources. Thus, the scheduler at the MAC layer of the base station plays a very important role in resource allocation to the user. In this study a novel algorithm for resource allocation in mobile environments is presented, with two variations addressing different input traffic. The …


An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan Jan 2018

An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan

Ronald Greenberg

A performance model for wormhole routed interconnection networks is presented and applied to the butterfly fat-tree network. Experimental results agree very closely over a wide range of load rate. Novel aspects of the model, leading to accurate and simple performance predictions, include (1) use of multiple-server queues, and (2) a general method of correcting queuing results based on Poisson arrivals to apply to wormhole routing. These ideas can also be applied to other networks.


An Optimized Multiobjective Cpu Job Scheduling Using Evolutionary Algorithms, Santhi Venkatraman, Dharshikha Selvagopal Jan 2018

An Optimized Multiobjective Cpu Job Scheduling Using Evolutionary Algorithms, Santhi Venkatraman, Dharshikha Selvagopal

Turkish Journal of Electrical Engineering and Computer Sciences

Scheduling in a multiprocessor parallel computing environment is an NP-hard optimization problem. The main objective of this work is to obtain a schedule in a distributed computing system (DCS) environment that minimizes the makespan and maximizes the throughput. We study the use of two of the evolutionary swarm optimization techniques, the firefly algorithm and the artificial bee colony (ABC) algorithm, to optimize the scheduling in a DCS. We also enhance the traditional ABC algorithm by merging the genetic algorithm techniques of crossover and mutation with the employed bee phase and the onlooker phase, respectively. The resulting enhanced ABC algorithm is …


Effects Of Routing Algorithms On Novel Throughput Improvement Of Mobile Ad Hoc Networks, Barbaros Preveze, Aysel Şafak Jan 2012

Effects Of Routing Algorithms On Novel Throughput Improvement Of Mobile Ad Hoc Networks, Barbaros Preveze, Aysel Şafak

Turkish Journal of Electrical Engineering and Computer Sciences

A cognitive method called most congested access first (MCAF), minimizing the packet loss ratio and improving the throughput of a multihop mobile WiMAX network, is proposed. MCAF combines both the time division multiple access and the orthogonal frequency division multiple access methods. MCAF additionally uses spectral aid and buffer management methods, which are proposed in this paper, to manage both spectrum access and packets in the buffers. By using these novel methods, real-time video and voice packet transmission is achieved, data packet loss rate is minimized, and the system throughput per node is improved. Effects of fastest path and ant …


Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood Aug 2009

Networks - I: A Comparative Analysis Of Dccp Variants (Ccid2, Ccid3), Tcp And Udp For Mpeg4 Video Applications, Muhammad Ajmal Azad, Rashid Mahmood, Tahir Mehmood

International Conference on Information and Communication Technologies

New emerging technologies like Multimedia applications require timely delivery of information as compared to reliability. The most widely used protocols over transport layer are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Both of these have some drawbacks while using in real time applications. TCP increases delay in transfer of data but achieving reliable transfer of data while UDP does not provide any acknowledgment, hence it overcomes the problem of delay but lacking congestion control mechanism. To provide congestion control over transport layer using UDP, Datagram Congestion Control Protocol (DCCP) has been designed to provide timely delivery of data …


A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu Aug 2008

A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu

Zheng Sun

Conventional heterogeneous-traffic scheduling schemes utilize zero-delay constraint for real-time services, which aims to minimize the average packet delay among real-time users. However, in light or moderate load networks this strategy is unnecessary and leads to low data throughput for non-real-time users. In this paper, we propose a heuristic scheduling scheme to solve this problem. The scheme measures and assigns scheduling priorities to both real-time and non-real-time users, and schedules the radio resources for the two user classes simultaneously. Simulation results show that the proposed scheme efficiently handles the heterogeneous-traffic scheduling with diverse QoS requirements and alleviates the unfairness between real-time …


Modeling And Comparison Of Wormhole Routed Mesh And Torus Networks, Ronald I. Greenberg, Lee Guan Oct 1997

Modeling And Comparison Of Wormhole Routed Mesh And Torus Networks, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

2D-mesh and torus networks have often been proposed as the interconnection pattern for parallel computers. In addition, wormhole routing has increasingly been advocated as a method of reducing latency. Most analysis of wormhole routed networks, however, has focused on the torus and the broader class of k-ary n-cubes to which it belongs. This paper presents a performance model for the wormhole routed mesh, and it compares the performance of the mesh and torus based on theoretical and empirical analyses.


An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan Aug 1997

An Improved Analytical Model For Wormhole Routed Networks With Application To Butterfly Fat-Trees, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

A performance model for wormhole routed interconnection networks is presented and applied to the butterfly fat-tree network. Experimental results agree very closely over a wide range of load rate. Novel aspects of the model, leading to accurate and simple performance predictions, include (1) use of multiple-server queues, and (2) a general method of correcting queuing results based on Poisson arrivals to apply to wormhole routing. These ideas can also be applied to other networks.