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Found 6319 publications

State space modeling theory of induction machines

Miklós Kuczmann Zoltan Nemeth

Publication Name: Pollack Periodica

Publication Date: 2020-04-01

Volume: 15

Issue: 1

Page Range: 124-135

Description:

The paper discusses the theoretical background of the state space modeling of induction machines. The main goal is to present the necessary equations of the induction machine and the topic of the state space modeling. Although the induction machine is a highly non-linear system, LPV/qLPV model can be formulated from these equations.

Open Access: Yes

DOI: 10.1556/606.2020.15.1.12

Extension of the Time Dependent Travelling Salesman Problem with Interval Valued Intuitionistic Fuzzy Model Applying Memetic Optimization Algorithm

Peter Foldesi Boldizsar Tuu-Szabo Ruba Almahasneh Ĺaszĺo T. Ḱoczy

Publication Name: ACM International Conference Proceeding Series

Publication Date: 2020-03-21

Volume: Unknown

Issue: Unknown

Page Range: 111-118

Description:

The Time Dependent Traveling Salesman Problem (TD TSP) is an extension of the classic Traveling Salesman Problem towards more realistic conditions. TSP is one of the most extensively studied NP-complete graph search problems. In TD TSP, the edges are assigned different weights, depending on whether they are traveled in the traffic jam regions (such as busy city centers) and during rush hour periods, or not. In such circumstances, edges are assigned higher costs, expressed by a multiplying factor. In this paper, we introduce a novel and even more realistic approach, the Interval Intuitionistic Fuzzy Time Dependent Traveling Salesman Problem (IVIFTD TSP); which is a further extension of the classic TD TSP, with the additional notion of deploying interval valued intuitionistic fuzzy for describing uncertainties. The core concept employs interval valued intuitionistic fuzzy sets for quantifying the traffic jam regions, and the rush hour periods loss (those are additional costs of the travel between nodes), which are always uncertain in real life. Since type-2 (such as inter valued) fuzzy sets have the potential to provide better performance in modeling problems with higher uncertainties than the traditional fuzzy set, the new approach it may be considered as an extended, practically more applicable, extended version of the original abstract problem. The optimization of such a complex model is obviously very difficult; it is a mathematically intractable problem. However, the Discrete Bacterial Memetic Evolutionary Algorithm proposed earlier by the authors' team has shown sufficient efficiency, general applicability for similar type problems and good predictability in terms of problem size, thus it is applied for the optimization of the concrete instances.

Open Access: Yes

DOI: 10.1145/3396474.3396490

Individual and institutional influences on EU labour market returns to education: a comparison of the effect of the 2008 economic crisis on eight EU countries

Ellu Saar Margarita Kazjulja Péter Róbert

Publication Name: European Societies

Publication Date: 2020-03-14

Volume: 22

Issue: 2

Page Range: 157-187

Description:

This paper explores cross-national variations in the impact of education on labour market outcomes using the risk of unemployment and occupational status as the key dependent variables. The study applies a comparative perspective on eight EU countries (three from CEE), representing different relationships between the education system and the labour market with various degrees of inequality, welfare provisions and labour market flexibility. A temporal comparison investigates the influence of the 2008 economic crisis. The study employs data from the European Union Labour Force Survey 2007, 2009 and 2014. Binary and ordinary least squares regressions are the main analytical methods. Models are fitted to the pooled data and interactions are applied to elaborate on country and temporal variations. The analysis reveals the persistence of returns to school investments; the crisis exerts bigger risk and loss for the less educated. However, this impact is markedly shadowed by the institutional variation at the country level. High flexibility and low inequality could provide some defence, while corporatist features and employment protection decreased the crisis effects. Post-communist countries were hit harder but with a characteristic variance: Slovenia was less affected, Estonia recovered the crisis faster and Hungary was affected at most.

Open Access: Yes

DOI: 10.1080/14616696.2019.1636110

Extracting LPV and qLPV structures from state-space functions: A TP model transformation based framework

Peter Baranyi

Publication Name: IEEE Transactions on Fuzzy Systems

Publication Date: 2020-03-01

Volume: 28

Issue: 3

Page Range: 499-509

Description:

This paper proposes a tensor product (TP) model transformation-based framework requiring minimal human intuition to numerically reconstruct linear time invariant, Takagi-Sugeno (T-S) fuzzy model-based linear parameter varying and quasi-linear parameter varying representations of state-space models. The proposed framework facilitates the manipulation of the structure of the system matrix, the parameter vector - including state elements - and the vertex systems. The motivation behind this capability is that all of these structural components strongly influence the control design and the resulting control performance. An important feature of the framework is that it is agnostic towards the formulation of the state-space model, i.e., whether it is given using soft-computing-based techniques or closed formulae. The proposed approach is an extension of the TP model-based control design framework and inherits all of its advantageous properties, e.g., it can be easily used to find minimal representations, including the higher order singular value-based canonical form, and it supports the clear formulation of complexity/accuracy tradeoffs and allows for conversions to various types of convex representations, making for a flexible way to manipulate the weighting and antecedent functions. This paper gives examples to show how the framework can be used in a routine-like fashion and to highlight how it can be applied to the problem of finding useful T-S fuzzy model variations of a given model.

Open Access: Yes

DOI: 10.1109/TFUZZ.2019.2908770

Experimental and numerical investigation of the single-point incremental forming of aluminium alloy foils

No authors available

Publication Name: Acta IMEKO

Publication Date: 2020-03-01

Volume: 9

Issue: 1

Page Range: 25-31

Description:

Single-Point Incremental Forming (SPIF) is a flexible process for manufacturing sheet metal parts that is well adapted and profitable for prototypes or small batch production. Compared to traditional sheet forming technologies, this relatively slow process can be used in different applications in the automotive and aircraft industries; architecture engineering; and medical aid manufacture. In this article, the indirectly obtained axial forming force on the SPIF of variable wall angle geometry is studied using different process parameters. The estimation of the forces on AlMn1Mg1 sheets with an initial thickness of 0.22 mm is performed by continuous monitoring of servomotor currents. The deformation states of the formed parts were analysed using the ARGUS optical strain measurement system of GOM, while the roughness measurements were carried out by a Mitutoyo system. Some initial finite element analysis simulations and a crack monitoring method together with an interaction plot of forming speed, incremental depth, tool diameter, and lubrication were also reported.

Open Access: No

DOI: DOI not available

Combining fuzzy signature and rough sets approach for predicting the minimum passing level of competency achievement

Siti Rochimah Umi Laili Yuhana Nurul Zainal Fanani Eko Mulyanto Yuniarno Mauridhi Hery Purnomo Ĺaszĺo T. Ḱoczy

Publication Name: International Journal of Artificial Intelligence

Publication Date: 2020-03-01

Volume: 18

Issue: 1

Page Range: 237-249

Description:

This paper aims to investigate the important factors that affect the value of the minimum passing level (MPL) of competency achievement and find the best method to predict it. The MPL of competency achievement is the value that represents the minimum passing score of examination related to the competency. Different schools may have a different value of the MPL because the MPL is defined based expert opinion on several uncertainty aspects and conditions at each school. This paper proposes the combination of rough sets and fuzzy signature method to predict the category of the MPL. The rough sets method is applied to reduce unnecessary features for classification and find the important factors to predict the MPL. The fuzzy signature is employed to predict the category of MPL based on the selected features. The method proposed in this paper consists of several stages, namely data collection and pre-processing, features selection, predict the category of the MPL using the combination of rough sets and fuzzy signatures method, and performance evaluation. Fifteen headmasters and sixty teachers of elementary schools participated in the data collection process. Based on the experiment with 203 objects data we achieved 97% accuracy in the prediction of MPL. The proposed method succeeded to identify the important factors on predicting the MPL on the complexity of competency and resource capacity of the school aspect. We obtained the improvement for accuracy of the complexity of competency prediction of 8.5% from the best method in the previous research.

Open Access: Yes

DOI: DOI not available

Active citizenship and civic competencies in the Hungarian City of győr

Adrienn Reisinger Daniel Robert Szabo Norbert Kovács

Publication Name: Citizenship Teaching and Learning

Publication Date: 2020-03-01

Volume: 15

Issue: 1

Page Range: 5-23

Description:

This article is based on the premise that participatory democracy needs active citizens, and active citizens need civic competencies. The goal of this study is to illustrate previous research into active citizenship and civic competencies and to add the own concept of the authors to the literature. The article also provides empirical results from a survey into active citizenship carried out among citizens in Győr, Hungary, 2017. A total of 254 citizens filled out the online and offline questionnaire. The survey sample methods included random and snowball sampling. The sample does not represent the population of Győr, 64.3 per cent were women and about half of the sample were graduate citizens, so the results can be interpreted only to the respondents. Results offer an insight into what citizens think of the concept of active citizenship and which civic competencies they regard as important active participation in society. The article also demonstrates guidance for practitioners and researchers and it adds to the literature on active citizenship. It is possible to believe that knowing what kind of civic competencies people need could be useful to know how to be more active in the society.

Open Access: Yes

DOI: 10.1386/ctl_00017_1

Experimental and numerical investigation of the single-point incremental forming of aluminium alloy foils

Imre Paniti Sherwan Mohammed Najm Dóra Harangozó Zsolt János Viharos

Publication Name: Acta Imeko

Publication Date: 2020-03-01

Volume: 9

Issue: 1

Page Range: 25-31

Description:

Single-Point Incremental Forming (SPIF) is a flexible process for manufacturing sheet metal parts that is well adapted and profitable for prototypes or small batch production. Compared to traditional sheet forming technologies, this relatively slow process can be used in different applications in the automotive and aircraft industries; architecture engineering; and medical aid manufacture. In this article, the indirectly obtained axial forming force on the SPIF of variable wall angle geometry is studied using different process parameters. The estimation of the forces on AlMn1Mg1 sheets with an initial thickness of 0.22 mm is performed by continuous monitoring of servomotor currents. The deformation states of the formed parts were analysed using the ARGUS optical strain measurement system of GOM, while the roughness measurements were carried out by a Mitutoyo system. Some initial finite element analysis simulations and a crack monitoring method together with an interaction plot of forming speed, incremental depth, tool diameter, and lubrication were also reported.

Open Access: Yes

DOI: DOI not available

Weed surveys and weed mapping in Europe: State of the art and future tasks

Garifalia Economou-Antonaka Guillaume Fried Ineta Vanaga Silvia Panozzo Hansjörg Krähmer Michaela Kolářová Gyula Pinke Jukka Salonen Robert Novák Edita Stefanic Josef Holec Maurizio Sattin Dionissios Kalivas Christian Andreasen

Publication Name: Crop Protection

Publication Date: 2020-03-01

Volume: 129

Issue: Unknown

Page Range: Unknown

Description:

Long-term national European weed surveys, large scale classical phytosociological programs and camera-based documentation systems lead to results which can be documented in form of maps. Comparisons of these visual representations of relative weed positions can be used for the prediction of changing weed spectra and of plant biodiversity changes. Statistical methods connected with mapping software are used for the analysis of environmental factors and of farm managing practices influencing the occurrence of weeds. Maps produced by sensor-driven weed detection devices still differ considerably from maps produced via classical phytosociological approaches. Computer algorithms may allow the precise identification of some weeds in camera images. The present technical solutions are, however, still far from those achieved by experienced botanists. Many weed detection tools based on algorithms are not able to distinguish between closely related weeds yet. A few European countries have a long tradition of surveying weeds in major crops by traditional tools. Various software packages are employed for the analysis, documentation and visualisation of survey results. Large scale comprehensive maps including the infestation of crops over different countries are, however, often biased as not every national research group uses the same methods for the assessment of weed infestation. The ranking of the most common species seems, however, to allow comparable conclusions. The recognition of trends in spectrum changes can only be derived from long term studies as we see it. Our review reflects discussions within the Weed Mapping Working Group of the European Weed Research Society over the last ten years. We try to identify new research trends and to respond accordingly with new research projects. What we see today is a shift from traditional mapping approaches towards the use of digital devices as for example in precision farming projects. Another issue of increasing importance is the mapping of herbicide resistant biotypes.

Open Access: Yes

DOI: 10.1016/j.cropro.2019.105010