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Found 6278 publications

Some remarks to the nanowires grown on III-V substrate

Ákos Nemcsics L. M. Molnár Imre Mojzes Zsolt J. Horváth Szilvia Nagy Eniko Horváth

Publication Name: Asdam 2008 Conference Proceedings of the 7th International Conference on Advanced Semiconductor Devices and Microsystems

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: 215-218

Description:

In the present work nanowires are investigated, which were prepared with the help of encapsulated metal induced growth method on GaAs and InP substrate. As our former investigations how, we can receive nanowires with substrate-like composition in the case of InP. In the case of GaAs substrate the situation is entirely different, while the growth technology in both cases was the same. The difference between the nanoproducts in the cases of different substrates originate in the reactivity of the components, which is explained in the following considerations. Furthermore we have observed that the diameter of the nanowires depends on the electron energy of the irradiation. If the electron beam was 5 kV and 20 kV, the diameter lasting increases and decreases, respectively. This effect can be explained by the change of the nanowires structure influenced by the electron beam. © 2008 IEEE.

Open Access: Yes

DOI: 10.1109/ASDAM.2008.4743320

Solving contact problems using the domain decomposition method with an interface preconditioner

Lotfi Abdelhakim G. Y. Molnarka

Publication Name: Proceedings of the 6th International Conference on Engineering Computational Technology

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The present paper is concerned with the frictionless bilateral or unilateral contact problem between two elastic bodies. An algorithm is introduced to solve the resulting finite element system by a non-overlapping domain decomposition method. This technique enable us to transform the solution of the global problem to the solutions of the elasticity equations for each body separately and the solution of the Schur complement problem on the contact surface. The main goal of this work is the construction of the interface preconditioner for the Schur complement problem. The solution is obtained by using a successive approximation method. Finally, some numerical results of the proposed method are given. © 2008 Civil-Comp Press.

Open Access: Yes

DOI: DOI not available

The roles and possibilities of cultural and social relationship in the development of tourism in Subcarpathia

Orsolya Zsellér Ferenc Katona

Publication Name: Sisy 2008 6th International Symposium on Intelligent Systems and Informatics

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The Central-East European region have undergone a radical change in the last 15 years. All of the political changes in regime also aimed at stabilizing the economies of the countries. Methods and short- and long-term results were different but each countries of the region strongly focuses on developing the sector of tourism, as they all realize the development opportunities of the service industry. In Hungary and its neighbors it is a recognizable trend in tourism that popular places of destination got chosen based on cultural and social connections and past relationships. This trend is truly recognizable in the view of Transilvanian and Slovakian tourism, but Subcarpathia is not so popular in spite of its thermal spas and cultural heritage. ©2008 IEEE.

Open Access: Yes

DOI: 10.1109/SISY.2008.4664950

Joint experiments on the Tokamaks CASTOR and Ta10

E. Dufkova J. Brotankova M. Berta R. Dejarnac A. Fonseca G. M. Vorobjev A. Talebitaher J. Sentkerestiova B. Tál R. Gonzales V. Soldatov E. Sukhov I. Ďuran I. El Chama Neto C. R.Gutierrez Tapia A. W. Kraemeraflecken J. G. Ferreira A. Singh H. Hegazy H. Hegazy P. Khorshid L. Ruchko G. Kirnev N. Kirneva E. Del Bosco V. Vershkov A. Malaquias M. Hron B. Kuteev G. Mank M. Gryaznevich L. I. Krupnik V. Budaev A. Ovsyannikov A. Melnikov G. Van Oost M. Sokolov Y. Kuznetsov P. Peleman J. Zajac S. Zoletnik V. Weinzettl J. Stöckel

Publication Name: Aip Conference Proceedings

Publication Date: 2008-12-01

Volume: 996

Issue: Unknown

Page Range: 24-33

Description:

Small tokamaks may significantly contribute to the better understanding of phenomena in a wide range of fields such as plasma confiement and energy transport; plasma stability in different magnetic configurations; plasma turbulence and its impact on local and global plasma parameters; processes at the plasma edge and plasmaawall interaction; scenarios of additional heating and nonainductive current drive; new methods of plasma profile and parameter control; development of novel plasma diagnostics; benchmarking of new numerical codes and so on. Furthermore, due to the compactness, flexibility, low operation costs and high skill of their personnel small tokamaks are very convenient to develop and test new materials and technologies. Small tokamaks are suitable and important for broad international cooperation, providing the necessary environment and manpower to conduct dedicated joint research programmes. In addition, the experimental work on small tokamaks is very appropriate for the education of students, scientific activities of postagraduate students and for the training of personnel for large tokamaks. The first Joint (Host Laboratory) Experiment (JE1) has been carried out in 2005 on the CASTOR tokamak at the IPP Prague, Czech Republic. It was jointly organized by the IPPaASCR and KFKI HAC, Budapest, involved 20 scientists from 7 countries and was supported through the IAEA and the ICTP, Trieste. The objective of JE1 was to perform studies of plasma edge turbulence and plasma confinement. Following the success of JE1, JE2 has been performed on Ta10 at RRC "Kurchatov Institute" in Moscow; 30 scientists from 13 countries participated in this experiment. This experiment aimed to continue JE1 turbulence studies, now extending them to the plasma core. Results of JE1 and JE2 will be overviewed and compared. © 2008 American Institute of Physics.

Open Access: Yes

DOI: 10.1063/1.2917019

Nodal and edge finite element analysis of eddy current field problems

Miklós Kuczmann

Publication Name: Przeglad Elektrotechniczny

Publication Date: 2008-12-01

Volume: 84

Issue: 12

Page Range: 194-197

Description:

Eddy current field problems can be solved by different potential formulations based on the "quasi-static" Maxwell's equations. The potential formulations are obtained using a vector potential and a scalar potential, the most widely used techniques are the A, V-A, the T,φ-φformulations and their combinations. Vector potentials can be approximated by nodal or edge finite elements, scalar potentials are approximated by scalar elements. The paper presents and compares these formulations through TEAM Problem No. 7 containing a multiply connected region.

Open Access: Yes

DOI: DOI not available

An application of the greedy heuristic of set cover to traffic checks

Pál Pusztai

Publication Name: Central European Journal of Operations Research

Publication Date: 2008-12-01

Volume: 16

Issue: 4

Page Range: 407-414

Description:

Let us suppose that X is a given, finite, not empty set and F is a given collection of subsets of X such that their union equals X, in other words F covers X. Set cover is the problem of selecting as few as possible subsets from F such that their union covers X. Max k-cover is the problem of selecting k subsets from F such that their union has maximum cardinality. Both problems are NP-hard. There is a polynomial time greedy heuristic that iteratively selects the subset from F that covers the largest number of yet uncovered elements. We implemented this greedy algorithm to support the planning of a checking system that is aimed to check the vehicles in a road network. We would like to answer such questions: - How many and which links are sufficient to check a given percentage of all traffic flow? - What percentage of traffic can be checked with given links? This paper defines the necessary data and basic knowledge, gives algorithms to answer the previous questions and also shows the results of an implementation in a road network that contains about 11,000 junctions, 3,000 origin-destination junctions and 26,000 links. © 2008 Springer-Verlag.

Open Access: Yes

DOI: 10.1007/s10100-008-0067-x

Real-time and parallel quality control processing on industrial production lines

N. Varjasi

Publication Name: Pollack Periodica

Publication Date: 2008-12-01

Volume: 3

Issue: 3

Page Range: 105-111

Description:

The subject of the article is the evaluation of three acoustical algorithms on industrial production lines. The algorithm is used for the inspection of work-pieces in a noisy industrial environment. High efficiency performance requirements restricted running time and expected precise results make these inspections problematic. A sequential and two parallel algorithms and processing methods for these measurements were developed. These algorithms are real-time and multi-channel processing methods on industrial production lines. They carry out series of precision measurements in the time frame available. After the inspection the quality class and usability of the pieces are determined. These computer-aided inspections are more effective than human measurements because they are more precise, can be repeated multiple times, even with different quality requirements. They are usable on high-speed industrial production lines to obtain results in digital format. © 2008 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/Pollack.3.2008.3.9

Improving social life and communication of people with disabilities by using internet facilities

Z. Puklus Attila Kürtösi Adina Ionescu Ileana Hamburg

Publication Name: Ceur Workshop Proceedings

Publication Date: 2008-12-01

Volume: 415

Issue: Unknown

Page Range: Unknown

Description:

This paper presents some European initiatives developed within the Socrates Programme in order to support people with disabilities to use the new technologies. The disadvantages of the existing software designed for people with visual deficiencies together with some criteria that have to be considered in developing virtual learning applications for visually impaired are pointed out. The paper includes a proposal for improvement of the existing software for searching information and communication by people with disabilities, the first version of the FORThSIGHT Programme, elaborated in the framework of one Grundtvig 2 Learning Partnership.

Open Access: Yes

DOI: DOI not available

Matrix factorization and neighbor based algorithms for the netflix prize problem

Bottyan Nemeth Istvan Pilaszy Gabor Takacs Domonkos Tikk

Publication Name: Recsys 08 Proceedings of the 2008 ACM Conference on Recommender Systems

Publication Date: 2008-12-01

Volume: Unknown

Issue: Unknown

Page Range: 267-274

Description:

Collaborative filtering (CF) approaches proved to be effective for recommender systems in predicting user preferences in item selection using known user ratings of items. This subfield of machine learning has gained a lot of popularity with the Netix Prize competition started in October 2006. Two major approaches for this problem are matrix factorization (MF) and the neighbor based approach (NB). In this work, we propose various variants of MF and NB that can boost the performance of the usual ensemble based scheme. First, we investigate various regularization scenarios for MF. Second, we introduce two NB methods: one is based on correlation coeficients and the other on linear least squares. At the experimentation part, we show that the proposed approaches compare favorably with existing ones in terms of prediction accuracy and/or required training time. We present results of blending the proposed methods. © 2008 ACM.

Open Access: Yes

DOI: 10.1145/1454008.1454049