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Found 5157 publications

Simulation of 3-dimensional cell population growth processes in polyhedral cellular systems

I. Zsoldos T. Reti

Publication Name: Materials Science Forum

Publication Date: 2007-01-01

Volume: 537-538

Issue: Unknown

Page Range: 579-590

Description:

In order to simulate the polyhedral grain nucleation in alloys, 3-D cell population growth processes are studied in space-filling periodic cellular systems. We discussed two different methods by which space-filling polyhedral cellular systems can be constructed by topological transformations performed on "stable" 3-D cellular systems. It has been demonstrated that an infinite sequence of stable periodic space-filling polyhedral systems can be generated by means of a simple recursion procedure based on a vertex based tetrahedron insertion. On the basis of computed results it is conjectured that in a 3-D periodic, topologically stable cellular system the minimum value of the average face number 〈f〉 of polyhedral cells is larger than eight (i.e. 〈f〉 > 8). The outlined algorithms (which are based on cell decomposition and/or cell nucleation) provide a new perspective to simulate grain population growth processes in materials with polyhedral microstructure.

Open Access: Yes

DOI: 10.4028/0-87849-426-x.579

Combination and interworking of four modelling methods for infocommunications and business process systems

László Muka Gábor Lencse

Publication Name: 5th International Industrial Simulation Conference 2007 Isc 2007

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 350-354

Description:

This paper describes how we can use four modelling methods together. We model Information and Communication Technology (ICT) systems and Business Process (BP) systems. The aim of the modelling is to experiment with the models, that is, simulation. Two of the methods are the detailed modelling of the ICT and of the BP systems, as we usually do that for discrete event simulation. The other two methods are those that enable us to make rapid performance analysis of these systems, namely Traffic-Flow Analysis (TEA) for ICT systems and Entity Flow-phase Analysis (EFA) for BP systems. The solutions for the combination and interworking of these methods are described.

Open Access: Yes

DOI: DOI not available

Resource allocation and its distributed implementation

Szabolcs Póta Zsolt Tibor Kosztyán Andrea Bencsik

Publication Name: Innovations and Advanced Techniques in Computer and Information Sciences and Engineering

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 511-518

Description:

During the execution of a project (investment, innovation etc.), three important parameters must be kept in mind: we have to execute the project as soon as possible, with minimal total cost and not to exceed resource (manpower, materials, engines etc.) availabilities. Why does it important to execute the project as soon as possible with minimal total cost? If more than one company compete for the execution of an investment project, usually the chance of winning the tender will be higher if a company can execute the project with minimal total project time (TPT) and minimal total project cost. This problem could already be handled in the 60s and 70s with network planning (CPM, MPM, PERT etc.), scheduling (Gantt Diagrams, LOB etc.) and other related cost-minimizing (CPM/COST, MPM/COST etc.) techniques. The most difficult problem was to handle the resources. During the execution of a project we must keep in view the resources, because these resources are usually straitened. There are well-defined number of labours, engines and so on. If we would like to execute the project with minimal TPT and minimal total project cost and optimal use of the resources (manpower, materials, engines etc.) the problem becomes easily so hard to solve (already at 5000-10000 activities) that computers available today cannot find the solution within a reasonable time. The real problem is more complicated, because before the execution of the project we can only estimate the duration time, (variable) cost and resource need of activities. In real life it is common that the duration time of project activities cannot be estimated correctly. In this paper a novel algorithm is introduced by which an optimal resource allocation with minimal total cost for any arbitrary project could be determined. Moreover, this algorithm also handles the competences of the human resources. A distributed problem solving environment is also introduced that implements the above mentioned optimal resource allocation algorithm with a parallel branch and bound method. The system is built on the Jini technology [44]. It is a dynamic, service-oriented infrastructure that utilizes spare cycles of networked workstations in an efficient way and solves computation intensive problems more easily due to the parallelization. © 2007 Springer.

Open Access: Yes

DOI: 10.1007/978-1-4020-6268-1_90

Component based hardware-software system for fuzzy controlling of automated vehicles

No authors available

Publication Name: Proceedings of SEFI and IGIP Joint Annual Conference 2007: Joining Forces in Engineering Educations Towards Excellence

Publication Date: 2007-01-01

Volume:

Issue:

Page Range: 397-398

Description:

Open Access: No

DOI: DOI not available

Takagi-sugeno fuzzy control models for large scale logistics systems

Gabriella Orbán István Harmati P. Várlaki

Publication Name: Isciii 07 3rd International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 199-203

Description:

Requirements, such as adaptive behavior, learning ability and self regulative features, that have to be met by modern logistic systems, need the construction of such control systems that are able to control the basic processes and also to develop and improve the material and information system by automating the control processes. For controlling the logistical systems the papers propose the application of LPV structure by which non-linear systems can be controlled on the basis of linear control theories. The proposal points out that the priorities of different states are of great importance when generating the logical rules of operation. For resolving the difficulties of constructing mathematical algorithms fuzzy sets are suggested, so in the control model a Takagi-Sugeno solution is proposed, that can describe multi-input multi-output, non-linear, dynamic systems like logistical systems. © 2007 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2007.367389

Effects of information technology investments on the efficiency of logistic processes

Gabriella Orbán

Publication Name: 14th World Congress on Intelligent Transport Systems ITS 2007

Publication Date: 2007-01-01

Volume: 7

Issue: Unknown

Page Range: 5238-5248

Description:

The output of logistics is performed by the appropriate and proportional use of material and information flows. Important issue is to determine the proper equilibrium between the resources devoted to the two main system elements. The necessity of continuous improvement of informatics and logistic flows is not questionable since the efficiency of logistics control systems can be increased by reducing the time gap between the time of gaining the data and use of information for planning purpose. In different logistics subsystems the role and importance of time gaps differ. Having generally overviewed the subsystems the papers introduce the efficiency of informatics based on Cobb-Douglas production function in order to spot the elements of logistics where the reduction of time gap is of economic interest, that is under what conditions can the IT developments and investment be efficient. Finally a draft framework is described as a general solution that can use informatic means in order to increase road transport system capacity usage.

Open Access: Yes

DOI: DOI not available

Investigation of the spatial distribution algorithm of the traffic flow analysis and of the entity flow-phase analysis

László Muka Gábor Lencse

Publication Name: Esm 2007 2007 European Simulation and Modelling Conference Modelling and Simulation 2007

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 291-295

Description:

This paper investigates an important algorithm that is used in both the Traffic-Flow Analysis and the Entity Flow-phase Analysis. These methods are similar to each other and can be used for the fast and approximate (performance) analysis of Information and Communication Technology (ICT) systems and Business Process (BP) systems. Both methods contain an algorithm for the spatial distribution of the traffic (or entities) in the system. It is shown how the error of the spatial distribution can be measured, and the effect of the so called size of routing unit parameter of two algorithms is investigated.

Open Access: Yes

DOI: DOI not available

Effects of information technology investments on the efficiency of logistic processes

No authors available

Publication Name: 14th World Congress on Intelligent Transport Systems, ITS 2007

Publication Date: 2007-01-01

Volume: 7

Issue:

Page Range: 5238-5248

Description:

The output of logistics is performed by the appropriate and proportional use of material and information flows. Important issue is to determine the proper equilibrium between the resources devoted to the two main system elements. The necessity of continuous improvement of informatics and logistic flows is not questionable since the efficiency of logistics control systems can be increased by reducing the time gap between the time of gaining the data and use of information for planning purpose. In different logistics subsystems the role and importance of time gaps differ. Having generally overviewed the subsystems the papers introduce the efficiency of informatics based on Cobb-Douglas production function in order to spot the elements of logistics where the reduction of time gap is of economic interest, that is under what conditions can the IT developments and investment be efficient. Finally a draft framework is described as a general solution that can use informatic means in order to increase road transport system capacity usage.

Open Access: No

DOI: DOI not available

Reconstruction decision model for trasportation infrastructure systems

István Pályi Ildikó Gombaszögi Lajos Tóth P. Várlaki

Publication Name: Isciii 07 3rd International Symposium on Computational Intelligence and Intelligent Informatics Proceedings

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 163-166

Description:

Improving transportation infrastructure raises several questions requiring complex analysis. Creating the mathematic model for transportation reconstruction needed developing a quick, dynamic programming process which considers the costs of single reconstruction phases and the direct or indirect profit emerging after completing reconstruction works. In the study we examined the application possibilities of the highly prestigious Bellman-theorem. We found that the combinatorial method for optimal distribution of investments is not very efficient in the current issue, although it applies the sequential method and the Bellman-theorem in a remarkable way. The method proposed in the study applies exponential partial profit-functions. The primary advantage is that it solves the problem of the complicated nonlinear dynamic programming on the basis of direct relations, without numeric analysis. Consequently, results are supplied quickly and the method allows solving enormous problems without any constraints. © 2007 IEEE.

Open Access: Yes

DOI: 10.1109/ISCIII.2007.367382