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Found 6289 publications

Example for convex hull tightening increasing the feasible parameter region at Linear Matrix Inequality based control design

Peter Varlaki Alexandra Szollosi Péter Baranyi

Publication Name: Ines 2014 IEEE 18th International Conference on Intelligent Engineering Systems Proceedings

Publication Date: 2014-09-24

Volume: Unknown

Issue: Unknown

Page Range: 175-180

Description:

The paper shows an example when the tightening of the convex hull determined by the vertexes of the polytopic Tensor Product model representation of a given quasi Linear Parameter Varying state-space model leads to feasible Linear Matrix Inequality based control design. In addition the paper unveils that the relaxation of the Tensor Product model complexity interferes also with the Linear Matrix Inequality feasibility results. The example at hand consists of the complex Nonlinear Aeroelastic Test Apparatus model of the three degree of freedom aeroelastic wing section model including Stribeck friction. The relaxation and convex hull tightening is based on the concept of the Tensor Product model transformation.

Open Access: Yes

DOI: 10.1109/INES.2014.6909364

Small-scale differences of urban nox exposition in field measurement data

Éva V.P. Rácz Zoltán Horváth

Publication Name: Wit Transactions on Ecology and the Environment

Publication Date: 2014-09-23

Volume: 191

Issue: Unknown

Page Range: 1513-1522

Description:

Local differences in air pollution levels of different positions of even close points along a street can be dramatic due to mainly meteorological parameters and local geometry. Air pollution monitoring systems provide a huge amount of temporal data, but the number of monitoring sites is far from sufficient for fine spatial investigations. On the other hand, for reliable air pollution modelling and correct prediction of expositions, a more detailed spatial distribution of samples is needed. Small-scale differences and street canyons are often investigated by models. However, such small-scale real field data from direct measurements are rarely available. In this paper we provide evidence by measurements to the existence of significant small-scale differences in air pollution levels and provide data for model validation. Hence, we performed measurements inside a single crossing and along three main roads in the city of Győr. Air samples were sucked into Tedlar bags and NOx concentration was determined by a gas analyser using a chemiluminescent method. On the sampling days manual traffic counting and noise measurements were performed and meteorological data were also taken at the same time. Daily rhythm and spatiotemporal variation of NOx expositions were investigated and compared to traffic data and data from the two monitoring containers of Győr. We observed a similar daily profile as expected in an average workday out of heating season: a sharp peak in the morning and a wider rise of nitrogen oxide concentration in the afternoon. Canyon effects were detected inside the investigated crossing. It caused a difference in pollutant levels of the two sides of the street. Despite a relatively small number of sampling sites, significant differences were detected both inside the crossing level and between main streets at p = 0.055.

Open Access: Yes

DOI: 10.2495/SC141282

A new fuzzy graph and signature based approach to describe fuzzy situational maps

Claudiu Radu Pozna Áron Ballagi L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2014-09-04

Volume: Unknown

Issue: Unknown

Page Range: 1340-1345

Description:

Computational tasks involving intelligent agents often need to process complex structured information. The way of describing this information greatly influences the performance of the agent. Therefore, a big issue is how the complex data describing that valuable information is not lose while it can also be processed in tractable time. Fuzzy signatures and their multidimensional geometric extension, fuzzy situational maps, are used to describe such complex structured data. These problems are examined in the context of a cooperative mobile robot task and a new method is developed for the simplified describing and processing of the complex inner relations in fuzzy situational maps. This paper mainly deals with the fundamentals of this method.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2014.6891862

On the development of signatures for Artificial Intelligence applications

Claudiu Radu Pozna Peter Foldesi Radu Emil Precup L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2014-09-04

Volume: Unknown

Issue: Unknown

Page Range: 1304-1310

Description:

This paper illustrates developments of signatures for Artificial Intelligence (AI) applications. Since the signatures are data structures with efficient results in modeling of fuzzy inference systems and of uncertain expert systems, the paper starts with the analysis of the data structures used in AI applications from the knowledge representation and manipulation point of view. An overview on the signatures, on the operators on signatures and on classes of signatures is next given. Using the proto fuzzy inference system, these operators are applied in a new application of fuzzy inference system modeled by means of signatures and of classes of signatures.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2014.6891636

Sensitivity analysis of the weighted generalized mean aggregation operator and its application to fuzzy signatures

Ádám Bukovics István Harmati L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2014-09-04

Volume: Unknown

Issue: Unknown

Page Range: 1327-1332

Description:

In this paper we give bounds on the changing of the weighted generalized mean in terms of vector norms of the changing of the variables. Applying this result we characterize the sensitivity of fuzzy signatures which equipped with weighted generalized mean operators in their nodes. Finally, a practical example from civil engineering is also examined.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2014.6891814

A survey of the influential factors of students' entrepreneurial career choice expectations

Adrienn Reisinger Norbert Kovács

Publication Name: Tarsadalomkutatas

Publication Date: 2014-09-01

Volume: 32

Issue: 3

Page Range: 278-294

Description:

In this paper we investigate the effect of family background and institution background on career choice intentions of Hungarian students based on the database of GUESSS 2011 international survey. Models, attitudes, morals from home often exert significant influence on children's walk of life. Our research focuses on the strength of familial and institutional effects on students' career choice expectations. The novelty of our study is that we analyse the factors in the whole sample and in the following parts of sample: students with and without family business background. In the first part of this study we show the former researches conducted in this topic, after it we show the career intentions of the higher education students in Hungary. The main part of our study is the analyses of the influential factors of career choice expectations of Hungarian students.

Open Access: Yes

DOI: 10.1556/Tarskut.32.2014.3.5

Occurrence and distribution of polycyclic aromatic hydrocarbons in surface water and sediments of the Danube River and its tributaries, Hungary

István Vass Andrea Szabó Nagy János Szabó

Publication Name: Journal of Environmental Science and Health Part A Toxic Hazardous Substances and Environmental Engineering

Publication Date: 2014-08-24

Volume: 49

Issue: 10

Page Range: 1134-1141

Description:

Polycyclic aromatic hydrocarbons (PAHs) were identified and quantified in surface water and sediments from 9 sites in the Hungarian upper section of the Danube River and its tributaries in autumn 2012. The total PAH concentrations (sum of the concentrations of 17 individual PAH compounds) in water samples ranged from 67 to 96 ng L-1, which were predominated by two- and three-ring PAHs. The total PAH concentrations in sediments ranged from 35.2 to 288.3 ng g-1 dw. Four-ring PAHs including fluoranthene and pyrene were the dominant species in sediment samples. The spatial distribution of PAHs in sediments was site-specific. The highest benzo[a]pyrene equivalent concentration was determined at the site located near a hazardous waste incinerator. However, the comparison of the total PAH concentrations determined with other sections of the Danube River and the environmental quality standards revealed that the PAH concentrations are relatively low in the Hungarian upper section. A selected number of concentration ratios of specific PAH compounds reflected a pattern of pyrogenic input as a major source of PAHs. Copyright © Taylor & Francis Group, LLC.

Open Access: Yes

DOI: 10.1080/10934529.2014.897155

Formation control of a large group of UAVs with safe path planning and obstacle avoidance

Gergely Regula Bela Lantos

Publication Name: 2014 European Control Conference Ecc 2014

Publication Date: 2014-07-22

Volume: Unknown

Issue: Unknown

Page Range: 1522-1529

Description:

In this article we propose a hierarchical control structure for multi-agent systems. The main objective is to perform formation change manoeuvres, with guaranteed safe distance between each two vehicles throughout the whole mission, even if motion is restricted to a limited space and static obstacles are present. The key components that ensure safety are a robust control algorithm that is capable of stabilising the group of vehicles in a desired formation and a higher level path generation method that provides all the vehicles with safe paths, based on graph theoretic considerations. The method can efficiently handle a large group of any type of vehicles. As an illustration, the results are applied to a group of 18 quadrotor UAVs, where 2 of the UAVs cannot receive information from the others.

Open Access: Yes

DOI: 10.1109/ECC.2014.6862411

Job mismatch in early career of graduates under post-communism

Péter Róbert

Publication Name: International Journal of Manpower

Publication Date: 2014-07-01

Volume: 35

Issue: 4

Page Range: 500-513

Description:

Purpose – The purpose of this paper is to investigate vertical and horizontal mismatch between education and current occupation for graduates in four post-communist societies: Hungary, Poland, Lithuania and Slovenia. In this way it contributes to the field by exploring how mechanisms, known from previous studies on western societies, affect job mismatch in emerging market economies. Design/methodology/approach – Two dependent variables are constructed: working in a nongraduate occupation as defined by the ISCO job title depicts vertical mismatch; assessment of the job from the perspective of the fields of study describes horizontal mismatch. Since the dependent variables are dichotomous ones, binary logistic regression models are fitted to the data predicting the incidence of mismatch. Explanatory variables cover mechanisms affecting job mismatch: variation by fields of studies, accumulated work experience during studies, labour market uncertainties during early career, trade off between job safety and job mismatch, persistence of “bad” labour market entry during early career, influence of parental background on school-to-work transition. Findings – The analysis reveals significant differences for study fields in association with occupational specificity of the disciplines. Only study-related work experience seems to be advantageous to find a matching job. Labour market uncertainties increase the probability of job mismatch. Job safety is more important than a matching job. Originality/value – Mismatch in first occupation has strong and long-lasting effect on the job match even five years after the graduation. The effect of parental background on job mismatch is curvilinear.

Open Access: Yes

DOI: 10.1108/IJM-05-2013-0113