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Found 6289 publications

Examining the accuracy and the precision of PDEs for FPGA computations

Zoltán Nagy András Kiss Árpád Csík Péter Szolgay

Publication Name: International Workshop on Cellular Nanoscale Networks and their Applications

Publication Date: 2012-12-13

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

There are a large number of problems which can be accelerated by using architectures on Field Programmable Gate Arrays (FPGA). However sometimes the complexity of a problem does not allow to map it onto a specific FPGA. In that case analysis of precision of the arithmetic unit which may solve the computational problem can be a good attempt to fit the architecture and to accelerate its computation. Numerical algorithm can be implemented using fixed-point or floating point arithmetic (or mixed (both)) with different precision. The aim of the article is not to optimize the numerical algorithm but to find a smaller arithmetic unit precision, which results enough accuracy and fits to smaller FPGA-s. In the paper, one particular problem type is investigated, namely the accuracy of the solution of a simple Partial Differential Equation (PDE). The accuracy measurement is done on an FPGA with different bit width. The solution of the advection equation is analyzed using first and second order discretization methods. As a result we managed to find an optimal bit width for the solution on a specific FPGA. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/CNNA.2012.6331439

Implementation of event driven software gates for combinational logic networks

József Kopják Janos Kovacs

Publication Name: 2012 IEEE 10th Jubilee International Symposium on Intelligent Systems and Informatics Sisy 2012

Publication Date: 2012-12-12

Volume: Unknown

Issue: Unknown

Page Range: 299-304

Description:

The paper presents one implementation possibility of event driven software model of distributed or classical combination logic networks. The paper first reviews the basics of event-driven systems. Greater part of article presents the mathematical basics and architecture of event-driven combinational logic and example software implementation of the model. The paper shows the software implementation of AND and OR gate. After the introduction of basic gates of combinational logic the paper introduces the concept of the universal event-driven gate. The paper ends with software implementation of symmetrical event-driven XOR gate to create odd and even functions. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/SISY.2012.6339533

FPGA based acceleration of computational fluid flow simulation on unstructured mesh geometry

Csaba Nemes Antal Hiba Zoltán Nagy András Kiss Árpád Csík Péter Szolgay

Publication Name: Proceedings 22nd International Conference on Field Programmable Logic and Applications Fpl 2012

Publication Date: 2012-12-12

Volume: Unknown

Issue: Unknown

Page Range: 128-135

Description:

Numerical simulation of complex computational fluid dynamics problems evolving in time plays an important role in scientific and engineering applications. Accurate behavior of dynamical systems can be understood using large scale simulations which traditionally requires expensive super-computing facilities. In the paper a Field Programmable Gate Array (FPGA) based framework is described to accelerate simulation of complex physical spatio-temporal phenomena. Simulating complicated geometries requires unstructured spatial discretization which results in irregular memory access patterns severely limiting computing performance. Data locality is improved by mesh node renumbering technique which results in a sequential memory access pattern. Additionally storing a small window of cell-centered state values in the on-chip memory of the FPGA can increase data reuse and decrease memory bandwidth requirements. Generation of the floating-point data path and control structure of the arithmetic unit containing dozens of operators is a very challenging task when the goal is high operating frequency. Efficiency and use of the framework is described by a case study solving the Euler equations on an unstructured mesh using finite volume technique. On the currently available largest FPGA the generated architecture contains three processing elements working in parallel providing 75 times speedup compared to a high performance microprocessor. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/FPL.2012.6339276

Creating and using Key Network-Performance Indicators to support the design of change of enterprise infocommunication infrastructure

László Muka Gergely Muka

Publication Name: Simulation Series

Publication Date: 2012-12-10

Volume: 44

Issue: BOOK 12

Page Range: 176-181

Description:

Nowadays, an increasing number of organisations have to make decisions about the change and optimization of their enterprise infocommunication infrastructure. The usual approach of performance (using QoS, SLA) is not user (enterprise) centred and complex enough to help ICT (Information and Communication Technology) experts to support management decisions. The paper proposes a strategic management inspired, user centred and complex method of creating KNPIs (Key Network-Performance Indicators) for the measurement. In the paper, a case study is introduced to illustrate the creation and the use of KNPIs: alternatives are generated for the change, and using KNPIs, the feasibility, capacity, quality and financial aspects - integrating also the business impact and the influence of user experience - of the change of the enterprise infocommunication infrastructure are examined and compared. In the case study, to the analysis and prediction of the necessary enterprise network capacities, network traffic simulation is used. Financial modelling is also applied in comparing the alternatives.

Open Access: Yes

DOI: DOI not available

A refinement of Sándor-Tóth's inequality

Claudiu Radu Pozna Nicuşor Minculete Radu Emil Precup

Publication Name: Journal of Inequalities and Applications

Publication Date: 2012-12-10

Volume: 2012

Issue: Unknown

Page Range: Unknown

Description:

The objective of this article is to show a refinement of Sándor-Tóth's inequality related to the arithmetic functions which use unitary divisors. A new estimate of the average order of the arithmetic function given by Sándor-Tóth's inequality is suggested. © 2012 Minculete et al.

Open Access: Yes

DOI: 10.1186/1029-242X-2012-4

A taxonomy of CogInfoCom trigger types in practical use cases

Adam B. Csapo Peter Varlaki Péter Baranyi

Publication Name: 3rd IEEE International Conference on Cognitive Infocommunications Coginfocom 2012 Proceedings

Publication Date: 2012-12-01

Volume: Unknown

Issue: Unknown

Page Range: 21-25

Description:

An important challenge in CogInfoCom is how to design multi-sensory signals which are capable of communicating high-level information to users. Although there have been investigations on how to design groups of signals for this purpose (referred to as CogInfoCom channels), and how to map high-level concepts onto patterns of sensory signals across different modalities, one general question has still not been addressed: how should a system decide when to provide information to users in interactive CogInfoCom systems? This paper represents an attempt to bridge this gap, and to provide a taxonomy of CogInfoCom trigger types in order to help answer this question. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2012.6421990

On the constant difference of Zagreb Indices

Marko Milošević Tamás Réti Dragan Stevanović

Publication Name: Match

Publication Date: 2012-12-01

Volume: 68

Issue: 1

Page Range: 157-168

Description:

Let Φ(z), z ∈ ℤ, be the set of all connected graphs whose difference of the second and the first Zagreb index is equal to z. We show that Φ(z) contains exactly one element, a star, for z < -2, while it is infinite for z ≥ -2. Moreover, all elements of Φ(-2) and Φ(-1) are trees, while Φ(0), besides trees, contains the cycles only Constructions of new elements of Φ(z) from the existing ones are based on the existence of vertices of degree two. We further show that the only elements of J z≤0Φ(z), which do not contain vertices of degree two, are stars and the molecular graphs of 2,3-dimethylbutane and 2,2,3-trimethylbutane.

Open Access: Yes

DOI: DOI not available

New energy management and hybrid energy storage for metro railcar

No authors available

Publication Name: 26th Electric Vehicle Symposium 2012, EVS 2012

Publication Date: 2012-12-01

Volume: 4

Issue:

Page Range: 2734-2742

Description:

This paper focuses on the use of model and simulation one of renewable energy. In this paper the results of simulation models by Matlab-Simulink for an urban-metro railcar and some newer methods for reducing the need value of capacitance for energy storage in cooperation by a Li-ion battery are presented. In this research was been investigated the Li-ion battery and the supercapacitor as hybrid energy storing device for the same task and its effectivness under operation of a suitable energy control system. The available decreasing ratio of the needed energy storage at case SCAP is 25 % to 40 % with this improved energy control method, which are significant values as decreasing in volume, mass and price. Mass reduction of our hybrid storage system is significant, about 60%.

Open Access: No

DOI: DOI not available

A general formulation of abduction algorithms

Claudiu Radu Pozna Radu Emil Precup

Publication Name: 3rd IEEE International Conference on Cognitive Infocommunications Coginfocom 2012 Proceedings

Publication Date: 2012-12-01

Volume: Unknown

Issue: Unknown

Page Range: 573-578

Description:

The paper offers a general formulation of abduction algorithms, referred to as minimum length solution algorithms, which are based on all observable states. The algorithms compute the necessary evidence to derive the correct hypothesis in minimum steps. A first version of algorithms is proposed such that to deal with situations when not all states are observable. The development of fuzzy inference systems is presented in order to apply the minimum length solution algorithms to sets of imprecise observations. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2012.6421956