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Found 6289 publications

Trace metal and metalloid levels in surface water of Marcal River before and after the Ajka red mud spill, Hungary

István Vass Andrea Szabó Nagy János Szabó

Publication Name: Environmental Science and Pollution Research

Publication Date: 2013-11-01

Volume: 20

Issue: 11

Page Range: 7603-7614

Description:

The aim of this study was to compare and assess the dissolved concentrations of trace elements (As, Zn, Hg, Cd, Cr, Ni, Pb and Cu) in surface water of Marcal River before and after the red mud spill that occurred in Ajka, western Hungary, in October 2010. The caustic sludge flooded the surrounding settlements and polluted the nearby Torna Creek, which flows through the Marcal and Raba rivers into the Danube. A total of 92 surface water samples were collected from the Marcal River in the period of 2007-2012 and analysed for dissolved trace metal(loid)s by atomic absorption spectroscopy method. After the spill, the water management authority initially focused on acid dosing of surface waters to lower pH and was effective in lowering both pH and metal(loid) concentrations. Among the dissolved trace metal(loid)s, arsenic and nickel levels were moderately higher in the Marcal River 2 years since the spill compared to that observed in the pre-disaster period. The concentrations of dissolved trace metal(loid)s did not exceed the European water quality standards and the US Environmental Protection Agency aquatic life criteria values (excluding one sample for cadmium). © 2013 Springer-Verlag Berlin Heidelberg.

Open Access: Yes

DOI: 10.1007/s11356-013-2071-5

Drivers of Regional Competitiveness in the Central European Countries

János Rechnitzer Imre Lengyel

Publication Name: Transition Studies Review

Publication Date: 2013-11-01

Volume: 20

Issue: 3

Page Range: 421-435

Description:

The examination of regional competitiveness has become a research question of outstanding importance in the Central European post-socialist countries since joining the EU. In our study we will proceed to analyse the competitiveness of 93 NUTS2 level regions of 8 Central European countries with the help of an empirical data base, using multivariable statistical methods. After introducing the database, we are going to investigate into the common revealed competitiveness indicator. Not only revealed competitiveness categories shall be analysed with the help of multivariable statistical procedures, but also the background processes described by the factor analysis and the multivariable linear regression model. © 2013 CEEUN.

Open Access: Yes

DOI: 10.1007/s11300-013-0294-2

Advanced learning of fuzzy cognitive maps of waste management by bacterial algorithm

Miklós F. Hatwágner Claudiu Radu Pozna Adrienn Buruzs L. T. Kóczy

Publication Name: Proceedings of the 2013 Joint Ifsa World Congress and NAFIPS Annual Meeting Ifsa NAFIPS 2013

Publication Date: 2013-10-31

Volume: Unknown

Issue: Unknown

Page Range: 890-895

Description:

Fuzzy cognitive maps (FCMs) are a very convenient and simple tool for modeling complex systems. They are popular due to their simplicity and user friendliness. However, according to [1], human experts are subjective and can handle only relatively simple networks therefore there is an urgent need to develop methods for automated generation of FCM models. The present research deals with the methodology of FCMs in combination with the Bacterial Evolutionary Algorithm (BEA). The method of FCMs using BEA seems to be suitable to model such complex mechanisms as integrated municipal waste management (IMWM) systems. This paper is an attempt to assess the sustainability of the IMWM system by investigating the FCM methodology based on the BEA with a holistic approach. As a result, the best scenario to an IMWM system can be assigned. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/IFSA-NAFIPS.2013.6608518

Solution of a fuzzy resource allocation problem by various evolutionary approaches

Peter Foldesi Zs Dányádi L. T. Kóczy

Publication Name: Proceedings of the 2013 Joint Ifsa World Congress and NAFIPS Annual Meeting Ifsa NAFIPS 2013

Publication Date: 2013-10-31

Volume: Unknown

Issue: Unknown

Page Range: 807-812

Description:

In this paper we present a fuzzy resource allocation and assignment problem and propose two types of biologically inspired optimization methods to solve it. The resources in question are used for the maintenance of a network of nodes, each with its specific maintenance demands over time. Our goal is to assign sufficient capacities to storage locations and transport the appropriate amount of resources to the nodes at specific times during the simulation, so that the total cost of storage, transportation and malfunction is kept to a minimum. We use fuzzy numbers to describe the parameters of all the scenarios a solution has to fit, such as the maintenance demands of each node, the additional expenditure that malfunctions bring, and also the varying cost of transportation between nodes and storage locations. The optimization methods we used were the bacterial evolutionary algorithm and the particle swarm algorithm, both with a plain and a memetic variant complemented with gradient-based local search. All of them had a version where they only worked with crisp values, and one with fuzzy solutions. We tested the effectiveness of these four approaches on four examples with varying network sizes and durations. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/IFSA-NAFIPS.2013.6608504

Constructing dense fuzzy systems by adaptive scheduling of optimization algorithms

Krisztián Balázs L. T. Kóczy

Publication Name: Proceedings of the 2013 Joint Ifsa World Congress and NAFIPS Annual Meeting Ifsa NAFIPS 2013

Publication Date: 2013-10-31

Volume: Unknown

Issue: Unknown

Page Range: 280-285

Description:

In this paper dense fuzzy rule based systems are constructed for solving machine learning problems. During the knowledge extraction process a scheduling approach is applied, which adaptively switches between the different optimization algorithms based on their convergence speed in the phases of the learning process, i.e. according to their respective local efficiency. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/IFSA-NAFIPS.2013.6608413

Cyclic motion generation for intelligent robot by evolutionary computation

János Botzheim Noriko Takase Naoyuki Kubota

Publication Name: Proceedings of the 2013 IEEE Workshop on Robotic Intelligence in Informationally Structured Space Riiss 2013 2013 IEEE Symposium Series on Computational Intelligence Ssci 2013

Publication Date: 2013-10-31

Volume: Unknown

Issue: Unknown

Page Range: 13-19

Description:

In this paper we propose a method for motion generation of intelligent multi-legged robot using evolutionary computation. Legged robot can walk in various complex terrains such as stairs as well as in flat environment. However, setting the robot's behavior to adapt to various environments in advance is very difficult. The robot can mimic the movement of organisms based on computational intelligence. In this study we apply steady state genetic algorithm for generating the motion sequence of a six-legged robot modeled by forward kinematics. The number of intermediate positions of the motion sequence is adapted to the environment and optimized as well. We use a computer simulation environment before we apply our method in real robot. This can reduce the time spent on finding the optimal parameter settings and the solution itself for the optimization problem. The solution is evaluated mainly on the moving distance of the robot. Experiments were conducted to confirm the proposed technique. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/RiiSS.2013.6607923

Improved fuzzy-based single-stroke character recognizer

A. Tormási L. T. Kóczy

Publication Name: Proceedings of the 2013 Joint Ifsa World Congress and NAFIPS Annual Meeting Ifsa NAFIPS 2013

Publication Date: 2013-10-31

Volume: Unknown

Issue: Unknown

Page Range: 430-435

Description:

In this paper we present two modified and improved versions of the formerly published Fuzzy-Based Single-Stroke Character Recognizer (FUBAR) algorithm. After introducing the original method, the study investigates the effects of two different improvements of the designed algorithm. The first extension is the use of symbol-dependent fuzzy grids to extract symbol features; the second one is the use of rule weights in hierarchical rule-bases. The accuracy and efficiency of the extended FUBAR algorithms are compared to previous results. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/IFSA-NAFIPS.2013.6608439

Towards the efficient simulation of telecommunication systems in heterogeneous distributed execution environments

László Muka István Derka Gábor Lencse

Publication Name: 2013 36th International Conference on Telecommunications and Signal Processing Tsp 2013

Publication Date: 2013-10-21

Volume: Unknown

Issue: Unknown

Page Range: 304-310

Description:

An introduction is given to the topics of the parallel and distributed simulation and of the modeling of telecommunications systems. Our practical modeling concept for simulation in heterogeneous execution environment is presented. Its logical topology is a star shaped network of homogeneous clusters. The load balancing and the coupling factor criteria are set up for building models of telecommunications systems so that the simulation may produce good speed-up in a heterogeneous distributed execution environment. A case study is given with the open source OMNeT++ discrete-event simulation system and its parallel CQN (closed queueing network) sample model executed by 64 CPU cores of four different types. Our criteria are heavily supported by the results of our experiments. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/TSP.2013.6613941

Performance analysis and comparison of the TAYGA and of the PF NAT64 implementations

Sándor Répás Gábor Lencse

Publication Name: 2013 36th International Conference on Telecommunications and Signal Processing Tsp 2013

Publication Date: 2013-10-21

Volume: Unknown

Issue: Unknown

Page Range: 71-76

Description:

The transition mechanisms for the first phase of IPv6 deployment are surveyed and the most important NAT64 solutions are selected. The test environment and the testing method are described. As for the selected NAT64 implementations, the performance of the TAYGA running under Linux and of the Packet Filter (PF) of OpenBSD was measured and compared. The stability of the tested NAT64 solutions was analyzed under serious overload conditions to test if they may be used in production environments with strong response time requirements. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/TSP.2013.6613894