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Found 6289 publications

M-estimators using optimization algorithm based on F-transform

Jin Hee Yoon Kisung Seo István Harmati Deokhwan Kyeong

Publication Name: Ifsa Scis 2017 Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems

Publication Date: 2017-08-30

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Robust estimation is an estimation technique which is insensitive to small departures from the idealized assumptions, especially inclusion of outliers of the data set. One of the popular robust technique is the so-called M-estimators. In a practical sense, there are many cases when the data set includes outliers, robust technique has been developed with various approaches due to its practical usefulness. In this paper, we propose a new algorithm based on F(Fuzzy)-transform and optimization algorithm, a modified GA (Genetic Algorithm). For this, two approaches are considered for comparison in order to minimize the objective functions of several robust M-estimators such as L1, L1 - L2 and Fair methods. One is a method which employs GA(Genetic Algorithm) as an optimization algorithm for minimization of the objective functions and the other one is a combined method based on F-transform and GA(Genetic Algorithm)which improves the accuracies. For a numerical example, the results are given with L2 (Least-squares) method, which is most popular but sensitive to outliers, for comparison. The performances are measured in RMSE, MAD and MAPE to show its superiority.

Open Access: Yes

DOI: 10.1109/IFSA-SCIS.2017.8023368

Soil moisture distribution mapping in topsoil and its effect on maize yield

Viliam Nagy G. Milics Zoltán Varga A. J. Kovács Attila Pörneczi Gábor Baranyai A. Nyéki Lubomír Lichner M. Neményi Tamás Németh

Publication Name: Biologia Poland

Publication Date: 2017-08-28

Volume: 72

Issue: 8

Page Range: 847-853

Description:

Soil moisture content directly influences yield. Mapping within field soil moisture content differences provides information for agricultural management practices. In this study we aimed to find a cost-effective method for mapping within field soil moisture content differences. Spatial coverage of the field sampling or TDR method is still not dense enough for site-specific soil management. Soil moisture content can be calculated by measuring the apparent soil electrical conductivity (ECa) using the Veris Soil EC-3100 on-the-go soil mapping tool. ECa is temperature dependent; therefore values collected in different circumstances were standardized to 25°C temperature (EC25). Constants for Archie's adjusted law were calculated separately, using soil temperature data. According to our results, volumetric moisture content can be mapped by applying ECa measurements in our particular field with high spatial accuracy. Even though within-field differences occure in the raw ECa map standardization to EC25 is recommended. Soil moisture map was also compared to yield map showing correlation (R2 = 0.5947) between the two datasets.

Open Access: Yes

DOI: 10.1515/biolog-2017-0100

Criticality analysis of purchased materials based on fuzzy signatures

Peter Foldesi Gabor Farkas L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2017-08-23

Volume: 0

Issue: Unknown

Page Range: Unknown

Description:

Selecting and evaluating the suppliers represent a very complex task, because a wide range of attributions must be taken into consideration and many of them are difficult to be made objectively quantified. The aim of this research is to provide a new model based on fuzzy signatures for selecting and evaluating the critical parts for the production.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2017.8015649

Applicability of various wavelet families in fuzzy classification of access networks' telecommunication lines

Ferenc Lilik L. T. Kóczy Szilvia Nagy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2017-08-23

Volume: 0

Issue: Unknown

Page Range: Unknown

Description:

The future of the smart society sets challenges for all types of existing telecommunication networks and links. For ensuring the optimal utilization of these networks precise performance predictions are necessary, especially in case of the symmetrical access networks with rather limited transmission capacity. It is also important to harness the already established infrastructure as long as it is technically possible, so that the use of the environmental resources would be minimal and the economical advantages would be maximal. In performance prediction of telecommunication links the high-dimensional input data, like the insertion loss spectrum, should be compessed. After reducing the dimension of the antecedent set, a fuzzy inference can be carried out for each of the lines. As the number of lines used for building the fuzzy sets is finite and the supports of the fuzzy set do not cover the whole space, a stabilized KH interpolation is used in the decision process. Wavelets constitute the basis of methods for compressing and analyzing data in many fields of science and technology. For the reduction of the input dimension, wavelets proved to be an effective tool. The applicability of various wavelet families with different sizes of filter coefficient sets are tested in the following considerations, with the result, that the wavelet type does not play an essential role as well as the length of the wavelets. Only the deepness of the wavelet transform influences essentially the goodness of the prediction: the remaining number of points should be 4 after the transformation.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2017.8015644

Interpolation in homogenous fuzzy signature rule bases

L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2017-08-23

Volume: 0

Issue: Unknown

Page Range: Unknown

Description:

Fuzzy signature sets (FSigSets) are extensions of the original fuzzy set concept, and also of the Vector Valued Fuzzy Set notion. In a FSigSet rule base the (input) universe of discourse X is mapped into a set of hierarchically grouped fuzzy sets, and each element of X has a 'membership degree' consisting of a rooted tree with membership degrees at each leaf and aggregations at the intermediate vertices. The structure of the tree is identical for each element in the case of homogenous FSigSets, and so are the aggregations, depending only on the position of the vertex. Interpolation in fuzzy rule bases allows the calculation of a conclusion in the output universe Y belonging to an observation even if there are gaps in the rule base and the observation does not intersect with any of the antecedent sets. The key question here is how to determine the degree of similarity, or inversely, the distance, of any observation from the surrounding antecedents of the rules in the base, so that the distance incorporates the information involved with the close connection of the features in the sub-groups, and the aggregations expressing the form of this connection. A solution is proposed, and a pair of numerical examples is presented.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2017.8015393

Measurement and Analysis of Vibration Levels in Rail Transport in Central Europe

Péter Böröcz S. Paul Singh

Publication Name: Packaging Technology and Science

Publication Date: 2017-08-01

Volume: 30

Issue: 8

Page Range: 361-371

Description:

In the last decade, with a continued change in world economic conditions and global trade, transportation of goods has continued to increase. The opening of new and existing markets requires that products and packages move through various regions of the world using available logistical equipment and networks at a faster pace. It also requires that damage be kept at a minimum while providing maximum safety to individuals. This can be achieved by properly designing packages to transportation levels that occur in the supply chain. The purpose of this research is to both measure and analyse the vibration physical forces that occur during rail transport. Rail shipments are widely used across the world, and they are an integral part of the intermodal transfer of ISO containers from ships and trucks to rail. The aim of this paper is to provide vibration levels measured for rail shipments on a major railway line in Central Europe that has not been previously published. The vibration levels that were measured in this study were compared with American Society of Testing and Materials, United States Military Standards and United Kingdom Defense Standard standards and International Safe Transit Association procedures in the form of power spectral density spectrums. A composite power spectral density spectrum is provided which can be used to simulate the measured rail vibration levels in Central Europe. Results are also compared with rail travel in other international shipments for North America and Asia. Copyright © 2016 John Wiley & Sons, Ltd.

Open Access: Yes

DOI: 10.1002/pts.2225

Hygrothermal behavior of ultralightweight polystyrene concrete

Máté Orosz Balázs Nagy Elek Tóth

Publication Name: Pollack Periodica

Publication Date: 2017-08-01

Volume: 12

Issue: 2

Page Range: 53-66

Description:

The aim of the paper is to investigate the hygrothermal properties of a newly developed ultra-lightweight polystyrene concrete, based on laboratory measurements. It describes the measuring process of thermal conductivities, and determines the declared thermal conductivity. The temperature and moisture conversion coefficients are determined, and new approximate functions are introduced. The paper describes the sorption and desorption isotherms, and gives polynomial approximate functions. The paper also investigates the temperature dependency of sorption curves. It determines the water absorption coefficient and the free water saturation. Furthermore, it describes the measuring process of the water vapor permeability. The water vapor resistance factor and water vapor diffusion-equivalent air layer thickness are calculated.

Open Access: Yes

DOI: 10.1556/606.2017.12.2.5

An effective Discrete Bacterial Memetic Evolutionary Algorithm for the Traveling Salesman Problem

Peter Foldesi Boldizsar Tuu-Szabo L. T. Kóczy

Publication Name: International Journal of Intelligent Systems

Publication Date: 2017-08-01

Volume: 32

Issue: 8

Page Range: 862-876

Description:

In recent years, a large number of evolutionary and other population-based heuristics were proposed in the literature. In 2009, we suggested to combine the very efficient bacterial evolutionary algorithm with local search as a new Discrete Bacterial Memetic Evolutionary Algorithm (DBMEA) (Farkas et al., In: Towards intelligent engineering & information technology, Studies in Computational Intelligence, Vol 243. Berlin, Germany: Springer-Verlag; 2009. pp 607–625). The method was tested on one of Traveling Salesman Problem (TSP) benchmark problems, and a difference was found between the real optimum calculated by the new and the published result because the Concorde and the Lin–Kernighan algorithm use an approximation substituting distances of points by the closest integer values. We modified the Concorde algorithm using real cost values to compare with our results. In this paper, we systematically investigate TSPLIB benchmark problems and other VLSI benchmark problems (http://www.math.uwaterloo.ca/tsp/vlsi/index.html) and compare the following values: optima found by the DBMEA heuristic and by the modified Concorde algorithm with real cost values, run times of DBMEA, modified Concorde, and Lin–Kernighan heuristic. In this paper, for the evaluation of metaheuristic techniques, we suggest the usage of predictability of the successful run in addition to the accuracy of the result and the computational cost as third property. We will show that in the case of DBMEA, the run time is more predictable than in the case of Concorde algorithm, so we suggest the use of DBMEA heuristic as very efficient for the solution of TSP and other nondeterministic polynomial-time hard optimization problems.

Open Access: Yes

DOI: 10.1002/int.21893

Solution procedure of dynamical contact problems with friction

Lotfi Abdelhakim

Publication Name: Aip Conference Proceedings

Publication Date: 2017-07-21

Volume: 1863

Issue: Unknown

Page Range: Unknown

Description:

Dynamical contact is one of the common research topics because of its wide applications in the engineering field. The main goal of this work is to develop a time-stepping algorithm for dynamic contact problems. We propose a finite element approach for elastodynamics contact problems [1]. Sticking, sliding and frictional contact can be taken into account. Lagrange multipliers are used to enforce non-penetration condition. For the time discretization, we propose a scheme equivalent to the explicit Newmark scheme. Each time step requires solving a nonlinear problem similar to a static friction problem. The nonlinearity of the system of equation needs an iterative solution procedure based on Uzawa's algorithm [2][3]. The applicability of the algorithm is illustrated by selected sample numerical solutions to static and dynamic contact problems. Results obtained with the model have been compared and verified with results from an independent numerical method.

Open Access: Yes

DOI: 10.1063/1.4992771