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Full-Text Articles in Computer Engineering

A P2p Computing System For Overlay Networks, Grzegorz Chmaj, Krzysztof Walkowiak Jan 2013

A P2p Computing System For Overlay Networks, Grzegorz Chmaj, Krzysztof Walkowiak

Electrical & Computer Engineering Faculty Research

A distributed computing system is able to perform data computation and distribution of results at the same time. The input task is divided into blocks, which are then sent to system participants that offer their resources in order to perform calculations. Next, a partial result is sent back by the participants to the task manager (usually one central node). In the case when system participants want to get the final result, the central node may become overloaded, especially if many nodes request the result at the same time. In this paper we propose a novel distributed computation system, which does …


Heuristic Algorithms For Optimization Of Task Allocation And Result Distribution In Peer-To-Peer Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak, Michal Tarnawski, Michal Kucharzak Sep 2012

Heuristic Algorithms For Optimization Of Task Allocation And Result Distribution In Peer-To-Peer Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak, Michal Tarnawski, Michal Kucharzak

Electrical & Computer Engineering Faculty Research

Recently, distributed computing system have been gaining much attention due to a growing demand for various kinds of effective computations in both industry and academia. In this paper, we focus on Peer-to-Peer (P2P) computing systems, also called public-resource computing systems or global computing systems. P2P computing systems, contrary to grids, use personal computers and other relatively simple electronic equipment (e.g., the PlayStation console) to process sophisticated computational projects. A significant example of the P2P computing idea is the BOINC (Berkeley Open Infrastructure for Network Computing) project. To improve the performance of the computing system, we propose to use the P2P …


Location Of Processor Allocator And Job Scheduler And Its Impact On Cmp Performance, Dawid Zydek, Grzegorz Chmaj, Alaa Shawky, Henry Selvaraj Mar 2012

Location Of Processor Allocator And Job Scheduler And Its Impact On Cmp Performance, Dawid Zydek, Grzegorz Chmaj, Alaa Shawky, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

High Performance Computing (HPC) architectures are being developed continually with an aim of achieving exascale capability by 2020. Processors that are being developed and used as nodes in HPC systems are Chip Multiprocessors (CMPs) with a number of cores. In this paper, we continue our effort towards a better processor allocation process. The Processor Allocator (PA) and Job Scheduler (JS) proposed and implemented in our previous works are explored in the context of its best location on the chip. We propose a system, where all locations on a chip can be analyzed, considering energy used by Network-on-Chip (NoC), PA and …


Decision Strategies For A P2p Computing System, Grzegorz Chmaj, Krzysztof Walkowiak Jan 2012

Decision Strategies For A P2p Computing System, Grzegorz Chmaj, Krzysztof Walkowiak

Electrical & Computer Engineering Faculty Research

Peer-to-Peer (P2P) computing (also called ‘public-resource computing’) is an effective approach to perform computation of large tasks. Currently used P2P computing systems (e.g., BOINC) are most often centrally managed, i.e., the final result of computations is created at a central node using partial results – what may be not efficient in the case when numerous participants are willing to download the final result. In this paper, we propose a novel approach to P2P computing systems. We assume that results can be delivered to all peers in a distributed way using three types of network flows: unicast, Peer-to-Peer and anycast. We …


Software Development Approach For Discrete Simulators, Grzegorz Chmaj, Dawid Maksymilian Zydek Aug 2011

Software Development Approach For Discrete Simulators, Grzegorz Chmaj, Dawid Maksymilian Zydek

Electrical & Computer Engineering Faculty Research

Simulation is the most common approach to perform the problem research. Among several types of simulation, the most common way is the discrete simulation, which assumes the division of the time scale into fixed length time slots. Depending on investigated problem, simulation packages may be used or it could be necessary to design and create own simulation system. In this paper, we propose the complete pre-study scheme and the most commonly appearing implementation problems with suggested solutions. We also describe how to implement the exemplary simulator in C++.


Random Approach To Optimization Of Overlay Public-Resource Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak Mar 2010

Random Approach To Optimization Of Overlay Public-Resource Computing Systems, Grzegorz Chmaj, Krzysztof Walkowiak

Electrical & Computer Engineering Faculty Research

The growing need for computationally demanding systems triggers the development of various network-oriented computing systems organized in a distributed manner. In this work we concentrate on one kind of such systems, i.e. public-resource computing systems. The considered system works on the top of an overlay network and uses personal computers and other relatively simple electronic equipment instead of supercomputers. We assume that two kinds of network flows are used to distribute the data in the public-resource computing systems: unicast and peer-to-peer. We formulate an optimization model of the system. After that we propose random algorithms that optimize jointly the allocation …


A Graph-Based Approach To Symbolic Functional Decomposition Of Finite State Machines, Piotr Szotkowski, Mariusz Rawski, Henry Selvaraj Jun 2009

A Graph-Based Approach To Symbolic Functional Decomposition Of Finite State Machines, Piotr Szotkowski, Mariusz Rawski, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

This paper discusses the symbolic functional decomposition method for implementing finite state machines in field-programmable gate array devices. This method is a viable alternative to the presently widespread two-step approaches to the problem, which consist of separate encoding and mapping stages; the proposed method does not have a separate decomposition step instead, the state's final encoding is introduced gradually on every decomposition iteration. Along with general description of the functional symbolic decomposition method's steps, the paper discusses various algorithms implementing the method and presents an example realisation of the most interesting algorithm. In the end, the paper compares the results …


Scheduling Architectures For Diffserv Networks With Input Queuing Switches, Mei Yang, Henry Selvaraj, Enyue Lu, Jianping Wang, S. Q. Zheng, Yingtao Jiang Jan 2009

Scheduling Architectures For Diffserv Networks With Input Queuing Switches, Mei Yang, Henry Selvaraj, Enyue Lu, Jianping Wang, S. Q. Zheng, Yingtao Jiang

Electrical & Computer Engineering Faculty Research

ue to its simplicity and scalability, the differentiated services (DiffServ) model is expected to be widely deployed across wired and wireless networks. Though supporting DiffServ scheduling algorithms for output-queuing (OQ) switches have been widely studied, there are few DiffServ scheduling algorithms for input-queuing (IQ) switches in the literaure. In this paper, we propose two algorithms for scheduling DiffServ DiffServ networks with IQ switches: the dynamic DiffServ scheduling (DDS) algorithm and the hierarchical DiffServ scheduling (HDS) algorithm. The basic idea of DDS and HDS is to schedule EF and AF traffic According to Their minimum service rates with the reserved bandwidth …


Free Regions Of Sensor Nodes, Laxmi P. Gewali, Navin Rongatana, Henry Selvaraj, Jan B. Pedersen Jan 2009

Free Regions Of Sensor Nodes, Laxmi P. Gewali, Navin Rongatana, Henry Selvaraj, Jan B. Pedersen

Electrical & Computer Engineering Faculty Research

We introduce the notion of free region of a node in a sensor network. Intuitively, a free region of a node is the connected set of points R in its neighborhood such that the connectivity of the network remains the same when the node is moved to any point in R. We characterize several properties of free regions and develop an efficient algorithm for computing them. We capture free region in terms of related notions called in-free region and out-free region. We present an O(n2) algorithm for constructing the free region of a node, where n is the number of …


Preliminary Study On Optimization Of Data Distribution In Resource Sharing Systems, Grzegorz Chmaj, Krzysztof Walkowiak Aug 2008

Preliminary Study On Optimization Of Data Distribution In Resource Sharing Systems, Grzegorz Chmaj, Krzysztof Walkowiak

Electrical & Computer Engineering Faculty Research

Grid structures are increasingly considered as very convergent with peer-to-peer networks. This paper presents a model of network acting both as grid and peer-to-peer network, used for data computation and distribution. Presented PPLC algorithm is a complete solution for both grid and peer-to-peer points of view. Problem formulation is presented, as well as solution heuristic algorithm and research results.


Significance Of Logic Synthesis In Fpga-Based Design Of Image And Signal Processing Systems, Mariusz Rawski, Henry Selvaraj, Bogdan J. Falkowski, Tadeusz Luba Jun 2008

Significance Of Logic Synthesis In Fpga-Based Design Of Image And Signal Processing Systems, Mariusz Rawski, Henry Selvaraj, Bogdan J. Falkowski, Tadeusz Luba

Electrical & Computer Engineering Faculty Research

This chapter, taking FIR filters as an example, presents the discussion on efficiency of different implementation methodologies of DSP algorithms targeting modern FPGA architectures. Nowadays, programmable technology provides the possibility to implement digital systems with the use of specialized embedded DSP blocks. However, this technology gives the designer the possibility to increase efficiency of designed systems by exploitation of parallelisms of implemented algorithms. Moreover, it is possible to apply special techniques, such as distributed arithmetic (DA). Since in this approach, general-purpose multipliers are replaced by combinational LUT blocks, it is possible to construct digital filters of very high performance. Additionally, …


Nesting System With Quantization And Knowledge Base Applied, Leszek Koszalka, Grzegorz Chmaj Apr 2007

Nesting System With Quantization And Knowledge Base Applied, Leszek Koszalka, Grzegorz Chmaj

Electrical & Computer Engineering Faculty Research

Nesting algorithms deal with placing two dimensional shapes on the given canvas. In this paper a binary way of solving the nesting problem is proposed. Geometric shapes are quantized into binary form, which is used to operate on them. After finishing nesting they are converted back into original geometrical form. Investigations showed, that there is a big influence of quantization accuracy for the nesting effect. However, greater accuracy results with longer time of computation. The proposed knowledge base system is able to strongly reduce the computational time.


Least Squares Support Vector Machine Based Classification Of Abnormalities In Brain Mr Images, S. Thamarai Selvi, D. Selvathi, R. Ramkumar, Henry Selvaraj Mar 2006

Least Squares Support Vector Machine Based Classification Of Abnormalities In Brain Mr Images, S. Thamarai Selvi, D. Selvathi, R. Ramkumar, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

The manual interpretation of MRI slices based on visual examination by radiologist/physician may lead to missing diagnosis when a large number of MRIs are analyzed. To avoid the human error, an automated intelligent classification system is proposed. This research paper proposes an intelligent classification technique to the problem of classifying four types of brain abnormalities viz. Metastases, Meningiomas, Gliomas, and Astrocytomas. The abnormalities are classified based on Two/Three/ Four class classification using statistical and textural features. In this work, classification techniques based on Least Squares Support Vector Machine (LS-SVM) using textural features computed from the MR images of patient are …


Efficient Scheduling For Sdmg Cioq Switches, Mei Yang, S. Q. Zheng Jan 2006

Efficient Scheduling For Sdmg Cioq Switches, Mei Yang, S. Q. Zheng

Electrical & Computer Engineering Faculty Research

Combined input and output queuing (CIOQ) switches are being considered as high-performance switch architectures due to their ability to achieve 100% throughput and perfectly emulate output queuing (OQ) switch performance with a small speedup factor S. To realize a speedup factor S, a conventional CIOQ switch requires the switching fabric and memories to operate S times faster than the line rate. In this paper, we propose to use a CIOQ switch with space-division multiplexing expansion and grouped input/output ports (SDMG CIOQ switch for short) to realize speedup while only requiring the switching fabric and memories to operate at the line …


A Fast And Simple Algorithm For Computing M-Shortest Paths In State Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar Jan 2004

A Fast And Simple Algorithm For Computing M-Shortest Paths In State Graph, M. Sherwood, Laxmi P. Gewali, Henry Selvaraj, Venkatesan Muthukumar

Electrical & Computer Engineering Faculty Research

We consider the problem of computing m shortest paths between a source node s and a target node t in a stage graph. Polynomial time algorithms known to solve this problem use complicated data structures. This paper proposes a very simple algorithm for computing all m shortest paths in a stage graph efficiently. The proposed algorithm does not use any complicated data structure and can be implemented in a straightforward way by using only array data structure. This problem appears as a sub-problem for planning risk reduced multiple k-legged trajectories for aerial vehicles.


Implementation Of Large Neural Networks Using Decomposition, Henry Selvaraj, H. Niewiadomski, P. Buciak, M. Pleban, Piotr Sapiecha, Tadeusz Luba, Venkatesan Muthukumar Jun 2002

Implementation Of Large Neural Networks Using Decomposition, Henry Selvaraj, H. Niewiadomski, P. Buciak, M. Pleban, Piotr Sapiecha, Tadeusz Luba, Venkatesan Muthukumar

Electrical & Computer Engineering Faculty Research

The article presents methods of dealing with huge data in the domain of neural networks. The decomposition of neural networks is introduced and its efficiency is proved by the authors’ experiments. The examinations of the effectiveness of argument reduction in the above filed, are presented. Authors indicate, that decomposition is capable of reducing the size and the complexity of the learned data, and thus it makes the learning process faster or, while dealing with large data, possible. According to the authors experiments, in some cases, argument reduction, makes the learning process harder.


A Simplistic Plasma Dust Removal Model Employing Radiation Pressure, Robert A. Schill Jr. Jun 2002

A Simplistic Plasma Dust Removal Model Employing Radiation Pressure, Robert A. Schill Jr.

Electrical & Computer Engineering Faculty Research

A simple heuristic model is developed to examine the feasibility of using radiation pressure as a means to transport plasma dust out of the path of the forthcoming electron or photon beam. A slow electromagnetic surface wave coupled to a planar target or substrate exerts the required pressure in the removal process. The model is examined using data and parameters from single-shot radiography experiments. Optimal source requirements are identified for a typical radiography experiment. Source energies and powers are a minimum over an optimum band of frequencies where both conduction and plasma oscillation effects are mutually significant. Above the band …


Characterizing And Calibrating A Large Helmholtz Coil At Low Ac Magnetic Field Levels With Peak Magnitudes Below The Earth's Magnetic Field, Robert A. Schill, Karin V. Hoff Jun 2001

Characterizing And Calibrating A Large Helmholtz Coil At Low Ac Magnetic Field Levels With Peak Magnitudes Below The Earth's Magnetic Field, Robert A. Schill, Karin V. Hoff

Electrical & Computer Engineering Faculty Research

Characterizing and calibrating a low impedance large Helmholtz coil generating 60 Hz magnetic fields with amplitudes well below the earth’s magnetic field is difficult and imprecise when coil shielding is not available and noise is an issue. Parameters influencing the calibration process such as temperature and coil impedance need to be figured in the calibration process. A simple and reliable calibration technique is developed and used to measure low amplitude fields over a spatial grid using a standard Hall effect probe gaussmeter. These low amplitude fields are typically hard or impossible to detect in the presence of background fields when …


Gallium Desorption Behavior At Algaas/Gaas Heterointerfaces During High-Temperature Molecular Beam Epitaxy, K. Mahalingam, D. L. Dorsey, K. R. Evans, Rama Venkat Aug 1997

Gallium Desorption Behavior At Algaas/Gaas Heterointerfaces During High-Temperature Molecular Beam Epitaxy, K. Mahalingam, D. L. Dorsey, K. R. Evans, Rama Venkat

Electrical & Computer Engineering Faculty Research

A Monte Carlo simulation study is performed to investigate the Ga desorption behavior during AlGaAs-on-GaAs heterointerface formation by molecular beam epitaxy. The transients in the Ga desorption rate upon opening the Al shutter are shown to be associated with the concurrent reduction in the V/III flux ratio. Monte Carlo simulations employing a constant V/III flux ratio yield a “steplike” variation in the Ga desorption rate with the resulting interfaces closer in abruptness to the ideal AlGaAs-on-GaAs interface. Further details on the stoichiometry of the interface and its relationship with predicted Ga desorption profiles is presented.


Theoretical Study Of A Linear Accelerator Used As A Vuv/X-Ray Source Using The Inverse Compton Scattering Mechanism: Comparisons And Applications, Robert A. Schill Jr., Edward Mccrea Mar 1997

Theoretical Study Of A Linear Accelerator Used As A Vuv/X-Ray Source Using The Inverse Compton Scattering Mechanism: Comparisons And Applications, Robert A. Schill Jr., Edward Mccrea

Electrical & Computer Engineering Faculty Research

A classical linear theory is used to compare large synchrotron sources to a rf linear accelerator employed as a VUV/X-ray source. Comparisons are made on a per-pulse basis. It is demonstrated that the linear accelerator as an X-ray source is comparable to large synchrotron accelerators with wiggler insertion devices at the experiment. Applications to lithography, X-ray microscopy, X-ray spectroscopy and detector calibration are examined. Excluding lithography, the linear accelerator with an appropriate laser source is a useful source of X rays for these applications. As verification, classical results are compared with quantum mechanical results and are shown to be in …


Comparison Of Time-Domain Reflectometry Performance Factors For Several Dielectric Geometries: Theory And Experiments, S. V. Maheshwarla, R. Venkatasubramanian, Robert F. Boehm Aug 1995

Comparison Of Time-Domain Reflectometry Performance Factors For Several Dielectric Geometries: Theory And Experiments, S. V. Maheshwarla, R. Venkatasubramanian, Robert F. Boehm

Electrical & Computer Engineering Faculty Research

We propose three nontraditional dielectric geometries and present an experimental and theoretical analysis and comparison of time domain reflectometry (TDR) performances for them. The traditional geometry (the probes inserted in material of essentially infinite extent) is compared to three nontraditional geometries where the probes are affixed outside of a core sample, inside of a bore, or flat on the surface of a semi-infinite solid. Our derivation relates the velocity of electromagnetic wave propagation to the complex permittivities and permeabilities of the media and the geometry for the three nontraditional configurations. Experimental results for air, styrofoam, dry sand, wet sand of …


A General Approach To Boolean Function Decomposition And Its Application In Fpgabased Synthesis, Tadeusz Luba, Henry Selvaraj Jan 1995

A General Approach To Boolean Function Decomposition And Its Application In Fpgabased Synthesis, Tadeusz Luba, Henry Selvaraj

Electrical & Computer Engineering Faculty Research

An effective logic synthesis procedure based on parallel and serial decomposition of a Boolean function is presented in this paper. The decomposition, carried out as the very first step of the .synthesis process, is based on an original representation of the function by a set of r-partitions over the set of minterms. Two different decomposition strategies, namely serial and parallel, are exploited by striking a balance between the two ideas. The presented procedure can be applied to completely or incompletely specified, single- or multiple-output functions and is suitable for different types of FPGAs including XILINX, ACTEL and ALGOTRONIX devices. The …


Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh Jul 1993

Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh

Electrical & Computer Engineering Faculty Research

We treat the question of control and stabilization of the elastic multibody system developed in the Phillips Laboratory, Edwards Air Force Base, California. The controlled output is judiciously chosen such that the zero dynamics are stable or almost stable. A variable structure control (VSC) law is derived for the end point trajectory control. Although, the VSC law accomplishes precise end point tracking, elastic modes are excited during the maneuver of the arm. A Linear stabilizer is designed for the final capture of the terminal state.