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Found 6273 publications

Laser powder deposition of tool steels: Strategies leading to homogeneous parts

Lino Costa Tamás Réti R. Vilar

Publication Name: Materials Science Forum

Publication Date: 2006-01-01

Volume: 514-516

Issue: PART 1

Page Range: 739-743

Description:

The microstructure and properties of tool steel parts built by laser powder deposition (LPD) depend considerably on the build-up strategy and on the processing parameters used. This dependence can lead to inconsistent results which may limit the widespread acceptance of LPD. There is, thus, a need for efficient process optimisation tools that take into consideration the complex phase transformations that may occur during the part build-up process and their effect on final properties. A model coupling finite element heat transfer calculations with transformation kinetic theory has been developed, which allows the microstructure and property distributions in parts produced by LPD to be predicted. Application of this model to the deposition of tool steels not only explains the origin of the heterogeneous distribution of properties usually mentioned in the literature but also allows designing build-up strategies that consistently lead to homogeneous, high quality parts. Its application to the study of the influence of substrate pre-heating and idle time between the deposition of consecutive layers is illustrated in the present paper.

Open Access: Yes

DOI: 10.4028/www.scientific.net/msf.514-516.739

Non-associative fuzzy flip-flop with dual set-reset feature

Rita Lovassy László T. Kóczy

Publication Name: Sisy 2006 4th Serbian Hungarian Joint Symposium on Intelligent Systems

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: 289-299

Description:

J-K flip-flops are the most general elementary units in sequential digital circuits. By extending Boolean operations to their respective fuzzy counterparts various fuzzy flipflops (F3) can be defined. Because of the axiomatic properties of fuzzy operations are considerably weaker then the properties satisfied by Boolean lattices, the minterm and maxterm type definitions of the same F3 are as a rule not equivalent. In former work we found a unique exception where simulation investigations lead to identical results for all parameter combinations examined. The base of this unique F3 is a pair of non-associative fuzzy connectives. In this paper the exact proof is given for the identity of the two definitions, i.e., for the uniqueness of the definition of this special non-associative F3.

Open Access: Yes

DOI: DOI not available

Generalised weighted relevance aggregation operators for hierarchical fuzzy signatures

János Botzheim B. Sumudu U. Mendis Tamás D. Gedeon László T. Kóczy

Publication Name: Cimca 2006 International Conference on Computational Intelligence for Modelling Control and Automation Jointly with Iawtic 2006 International Conference on Intelligent Agents Web Technologies

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Hierarchical Fuzzy Signatures are generalizations of the Vector Valued Fuzzy Set concept introduced in the 1970s. A crucial question in the Fuzzy Signature context is what kinds of aggregations are applicable for combining data with partly different substructures. Our earlier work introduced the Weighted Relevance Aggregation method to enhance the accuracy of the final results of calculations based on Hierarchical Fuzzy Signature Structures. In this paper, we further generalise the weights and the aggregation into a new operator called Weighted Relevance Aggregation Operator (WRAO). WRAO enhances the adaptability of the fuzzy signature model to different applications and simplifies the learning of fuzzy signature models from data. We also show the methodology of learning these aggregation operators from data. © 2006 IEEE.

Open Access: Yes

DOI: 10.1109/CIMCA.2006.110

Selective heating of different grain parts of wheat by microwave energy

E. Szijjártó A. J. Kovács E. Pallai-Varsányi M. Neményi

Publication Name: Advances in Microwave and Radio Frequency Processing Report from the 8th International Conference on Microwave and High Frequency Heating

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: 312-320

Description:

The aim of author's research work was to investigate the effect of process parameters and microwave heat treatment condition on the inactivation of &-amylase enzyme being in wheat grains, responsible for decomposition of starch molecules without considerable damage of the gluten content. The task was furthermore to clear up the possibilities of selective moistening of the different wheat grain parts containing the &-amylase enzyme and the valuable gluten protein. For checking the results Magnetic Resonance Imaging method was used. © Springer-Verlag Berlin Heidelberg 2006.

Open Access: Yes

DOI: 10.1007/978-3-540-32944-2_33

On the issue of learning weights from observations for fuzzy signatures

B. Sumudu U. Mendis Tamás D. Gedeon László T. Kóczy

Publication Name: 2006 World Automation Congress Wac 06

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

We investigate the issue of obtaining weights, which are associated with aggregation in fuzzy signatures, from real world data, Our approach will provide a way to extract the relevance of lower levels to the higher levels of the hierarchical fuzzy signature structure. We also handle the non-differentiability of max-min aggregation functions for gradient based learning. A mathematically proved method, which is found in the literature to approximate the derivatives of max-min functions, has been used. Copyright - World Automation Congress (WAC) 2006.

Open Access: Yes

DOI: 10.1109/WAC.2006.376058

Classification of time series via wavelet subband analysis using support vector machine classifier

B. Benyo Béla Paláncz

Publication Name: Periodica Polytechnica Electrical Engineering

Publication Date: 2006-01-01

Volume: 50

Issue: 1-2

Page Range: 129-140

Description:

An improved feature extraction method has been developed for classification and identification of time series, in case of the number of the experiments are considerably less than that of the samples in time series. The method based on the subband analysis of the wavelet transformation of the time signals, provides lower dimension feature vectors as well as much more robust kernel-based classifier than the traditional wavelet-based feature extraction method does. The application of this technique is illustrated by the classification of cerebral blood flow oscillation using support vector classifier with Gaussian kernel. The computations were carried out with Mathematica 5.1 and its Wavelet Application.

Open Access: Yes

DOI: DOI not available

An optimization model for maintenance of engineering structures

K. Ambrus-Somogyi András Bakó

Publication Name: Iccc 2005 IEEE 3rd International Conference on Computational Cybernetics Proceedings

Publication Date: 2005-12-01

Volume: 2005

Issue: Unknown

Page Range: 265-268

Description:

With the recognition that the engineering structures maintenance and repair needs far exceed the rescourses available to adress these needs, many firms have to turned to the development of ESMS (Enginnering Structures Management System) as a method to improve the allocation of these limited resources and the condition of their engineering structures. The paper provides an overviev of the need for ESMS. The concepts of level-of-service goals for functional adequacy, deterioration modeling and the relation of structural adequancy and optimization strategies for rescource allocation.

Open Access: Yes

DOI: 10.1109/ICCCYB.2005.1511584

Evaluation of HRTF data using the head-Related Transfer Function Differences

András Illényi György Wersényi

Publication Name: Forum Acusticum Budapest 2005 4th European Congress on Acustics

Publication Date: 2005-12-01

Volume: Unknown

Issue: Unknown

Page Range: 2475-2479

Description:

A simple spectral computation method is introduced for the evaluation of differences in dummy-head Head-Related Transfer Functions (HRTFs). These transfer functions describe the directional-dependent filtering of the outer ears and are responsible for basic localization cues. Head-Related Transfer Function Differences (HRTFDs) are defined as the quotient of measured HRTFs in the same direction, comparing the cases of modified environmental conditions. The HRTFDs are relative measures and thus free from systematic errors of the measurement system and individual parameters. Our experience shows that HRTFDs are well suited to analyze the fine structure of measured HRTF data and for representation of the changes in the acoustical environment near or on the head. HRTFDs of a BK dummy-head will be shown representing differences from about 1 dB. This measurement accuracy was determined by replacing the dummy-head with an omnidirectional microphone.

Open Access: Yes

DOI: DOI not available

Applying intelligent methods in logistics control

Tamás Hartványi Lajos Tóth László T. Kóczy

Publication Name: Iccc 2005 IEEE 3rd International Conference on Computational Cybernetics Proceedings

Publication Date: 2005-12-01

Volume: 2005

Issue: Unknown

Page Range: 71-74

Description:

The purpose of this research and development project is to construct the foundations of a logistics IT center with a universal and intermodal character, i.e., covering all modes of transportation and corresponding central functions related to warehouses and container terminals. Through its modular structure it is applicable to arbitrary concrete site dependent needs. It also contains intelligent elements, which offer suboptimal solutions to certain classic mathematical optimization problems connected to logistics, acceptable from a practical point of view and tractable in the computer science sense. In order to realize and implement this system, several basic research tasks both in logistics and IT will be solved. A model for a logistics center will be constructed, suitable for present infrastructural situation in Central and Eastern Europe but compatible with European Union standards.

Open Access: Yes

DOI: 10.1109/ICCCYB.2005.1511551