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Found 5164 publications

Fuzzy rule extraction by bacterial memetic algorithms

J. Botzheim C. Cabrita A. E. Ruano L. T. Koczy

Publication Name: International Journal of Intelligent Systems

Publication Date: 2009-03-01

Volume: 24

Issue: 3

Page Range: 312-339

Description:

In our previous papers, fuzzy model identification methods were discussed. The bacterial evolutionary algorithm for extracting fuzzy rule base from a training set was presented. The Levenberg-Marquardt method was also proposed for determining membership functions in fuzzy systems. The combination of the evolutionary and the gradient-based learning techniques is usually called memetic algorithm. In this paper, a new kind of memetic algorithm, the bacterial memetic algorithm., is introduced for fuzzy rule extraction. The paper presents how the bacterial evolutionary algorithm can be improved with the Levenberg-Marquardt technique. © 2009 Wiley Periodicals, Inc.

Open Access: Yes

DOI: 10.1002/int.20338

Effect of emulated head-tracking for reducing localization errors in virtual audio simulation

György Wersényi

Publication Name: IEEE Transactions on Audio Speech and Language Processing

Publication Date: 2009-02-01

Volume: 17

Issue: 2

Page Range: 247-252

Description:

Virtual audio simulation uses head-related transfer function (HRTF) synthesis and headphone playback to create a sound field similar to real-life environments. Localization performance is influenced by parameters such as the recording method and the spatial resolution of the HRTFs, equalization of the measurement chain as well as common headphone playback errors. The most important errors are in-the-head localization and front-back reversals. Among other cues, small movements of the head are considered to be important to avoid these phenomena. This study uses the BEACHTRON sound card and its HRTFs for emulating small head-movements by randomly moving the virtual sound source to emulate head-movements. This method does not need any additional equipment, sensors, or feedback. Fifty untrained subjects participated in the listening tests using different stimuli and presentation speed. A virtual target source was rendered in front of the listener by random movements of 1 -7 . Experiments showed that this kind of simulation can be helpful to resolve in-the-head localization, but there is no clear benefit for resolving front-back errors. Emulation of small head-movements of 2 could actually increase externalization rates in about 21% of the subjects while presentation speed is not significant. © 2009 IEEE.

Open Access: Yes

DOI: 10.1109/TASL.2008.2006720

Introduction of simulation method and possibilities of standardisation

András Pfeiffer János Jósvai József Perger Botond Kádár

Publication Name: International Workshop on Modeling and Applied Simulation Mas 2009 Held at the International Mediterranean and Latin American Modeling Multiconference I3m 2009

Publication Date: 2009-01-01

Volume: Unknown

Issue: Unknown

Page Range: 224-231

Description:

The paper focuses on the applicability of simulation technology in several hierarchical levels of a production oriented industrial firm. The topic of the paper addresses the discrete event simulation technology which is used to model the material flow and the manufacturing processes in the company. This paper would like to show some practice experience about the industrial introduction steps of manufacturing simulation, as well as our recent research result in the field of standardized simulation model building and data handling procedure.

Open Access: Yes

DOI: DOI not available

Production process modeling and planning wih simulation method, mounting process optimisation

No authors available

Publication Name: International Workshop on Modeling and Applied Simulation, MAS 2009, Held at the International Mediterranean and Latin American Modeling Multiconference, I3M 2009

Publication Date: 2009-01-01

Volume:

Issue:

Page Range: 240-245

Description:

The paper focuses on the establishment of the production program using simulation technology in a structure, where several products and high amount of variants per product are produced. The topic of the paper addresses the discrete event simulation technology which is used to model the material flow and the manufacturing processes in the production area. This paper would like to show and describe the modelling steps of a complex production system with a lot of products and three different line parts, which are connected with buffers.

Open Access: No

DOI: DOI not available

Scalable collaborative filtering approaches for large reeommender systems

Bottyán Németh István Pilászy Gábor Takács Domonkos Tikk

Publication Name: Journal of Machine Learning Research

Publication Date: 2009-01-01

Volume: 10

Issue: Unknown

Page Range: 623-656

Description:

The collaborative filtering (CF) using known user ratings of items has proved to be effective for predicting user preferences in item selection. This thriving subfield of machine learning became popular in the late 1990s with the spread of online services that use recommender systems, such as Amazon, Yahoo! Music, and Netflix. CF approaches are usually designed to work on very large data sets. Therefore the scalability of the methods is crucial. In this work, we propose various scalable solutions that are validated against the Netflix Prize data set, currently the largest publicly available collection. First, we propose various matrix factorization (MF) based techniques. Second, a neighbor correction method for MF is outlined, which alloys the global perspective of MF and the localized property of neighbor based approaches efficiently. In the experimentation section, we first report on some implementation issues, and we suggest on how parameter optimization can be performed efficiently for MFs. We then show that the proposed scalable approaches compare favorably with existing ones in terms of prediction accuracy and/or required training time. Finally, we report on some experiments performed on MovieLens and Jester data sets.

Open Access: Yes

DOI: DOI not available

Optical torque sensor development

A. Nagy P. Horváth

Publication Name: Recent Advances in Mechatronics 2008 2009

Publication Date: 2009-01-01

Volume: Unknown

Issue: Unknown

Page Range: 91-96

Description:

The purpose of this study is to develop a contactless torque sensor in the mNm range. The applied optical method is based on the birefringe effect of photoelastic materials. The novelty of the modified reflective photoelastic method is the application of a photoelastic tube as a coupling and measuring element between shafts. Change in intensity of polarized light is proportional to the torque to be measured. Basics of operational principle and practical considerations are also discussed.

Open Access: Yes

DOI: 10.1007/978-3-642-05022-0_16

Several meshless solution techniques for the stokes flow equations

Csaba Gáspár

Publication Name: Computational Methods in Applied Sciences

Publication Date: 2009-01-01

Volume: 11

Issue: Unknown

Page Range: 141-158

Description:

The permanent 2D Stokes flow is considered. The applied solution technique is the classical pressure correction method, which converts the original problem to a sequence of Poisson equations. These Poisson equations are discretized and solved in a meshless way, using local interpolation based on radial basis functions. Further improvement can be achieved by using a direct multi-elliptic approach instead of local interpolation, which results in re-globalized, quadtree-based schemes. The number of unknowns can be reduced by applying the method of fundamental solutions. A special regularization technique is introduced which uses higher order fundamental solutions without singularities. This regularization is combined with the direct multi-elliptic interpolation, which significantly reduces the computational cost and makes it possible to avoid the use of dense and ill-conditioned matrices.

Open Access: Yes

DOI: 10.1007/978-1-4020-8821-6_9

Small and silly? or private pitfall of small and medium-sized enterprises

No authors available

Publication Name: World Academy of Science, Engineering and Technology

Publication Date: 2009-01-01

Volume: 37

Issue:

Page Range: 482-488

Description:

Knowledge and these notions have become more and more important and we speak about a knowledge based society today. A lot of small and big companies have reacted upon these new challenges. But there is a deep abyss about knowledge conception and practice between the professional researchers and company -life. The question of this research was: How can small and mediumsized companies be equal to the demands of new economy? Questionnaires were used in this research and a special segment of the native knowledge based on economy was focused on. Researchers would have liked to know what the sources of success are and how they can be in connection with questions of knowledge acquisition, knowledge transfer, knowledge utilization in small and medium-sized companies. These companies know that they have to change their behaviour and thinking, but they are not on the suitable level that they can compete with bigger or multinational companies. © 2009 WASET.ORG.

Open Access: No

DOI: DOI not available

Developing fuzzy cognitive maps for modeling regional waste management systems

R. C. Pozna A. Buruzs L. T. Koczy

Publication Name: Civil Comp Proceedings

Publication Date: 2009-01-01

Volume: 92

Issue: Unknown

Page Range: Unknown

Description:

Sustainable waste management systems necessarily include environmental, economic, social, institutional, legal and technical aspects. As a result of the incompleteness and multiple uncertainties occurring in sustainable waste management systems, we propose the use of fuzzy cognitive maps (FCM) to support the planning and decision making process. It is obvious that uncertainties involved with waste management represent vagueness rather than probability. Fuzzy sets and fuzzy logic are suitable to construct a formal description and a mathematically manageable model of systems and processes with such uncertainties. In the research described in this paper the FCM model of the Gyor RWMS is established and implemented in such a structure that its parameters and weights were flexibly variable. By observation of the model and its time dependent behaviour we determined under what conditions the long-term sustainability of a regional waste management system could be ensured. In this paper, the interpretation of the results obtained by the FCM model for the actual waste management system are presented. © Civil-Comp Press, 2013.

Open Access: Yes

DOI: DOI not available