Sapientia University

Sighișoara, Romania

Sapientia University

Sighișoara, Romania
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Katai Z.,Sapientia University
Computer Applications in Engineering Education | Year: 2011

In this paper, we are going to introduce a new multi-sensory method and software, which improve the teaching-learning process of the recursive procedures and functions. The presented method can also be categorized as a blending or hybrid teaching-learning strategy that applies to technologically enhanced pedagogy. (The software was initially designed to be utilized especially in the teaching phase of the educational process, but it can also be efficiently used as an e-learning tool.) Copyright © 2009 Wiley Periodicals, Inc.


Antal M.,Sapientia University | Koncz S.,Sapientia University
Expert Systems with Applications | Year: 2011

Detecting weaknesses in students' knowledge may constitute an objective of testing. Computerized test systems, which can be tailored to students' knowledge level, are appropriate to realize this objective. These systems are not only used to reveal the students' knowledge, but also help tutors understand the problems in the educational process. This paper reviews the student modeling problem for computer-based test systems, and also proposes a novel method for the graphical representation of student knowledge. First, we present our test practice system 'Intelligent', which is followed by the evaluation of the system in real classroom conditions as well as the effect over students' knowledge acquisition. © 2010 Elsevier Ltd. All rights reserved.


Katai Z.,Sapientia University
Journal of Computer Assisted Learning | Year: 2015

The research results we present in this paper reveal that properly calibrated e-learning tools have potential to effectively promote the algorithmic thinking of both science-oriented and humanities-oriented students. After students had watched an illustration (by a folk dance choreography) and an animation of the studied sorting algorithm (bubble sort), they were invited to predict and perform [(1) to reconstruct on the same input; (2) to orchestrate on a random sequence stored in a white array; (3) to orchestrate on a black-box sequence] the entire step sequence of the algorithm (using the interactive visual learning environment we developed). The results of the experiment show that while science-oriented students' performance proved superior to those of their humanities-oriented colleagues, the differences were observed to diminish as both groups advanced with their e-learning tasks. Although drawing general conclusions would be premature, we can conclude that there are no unbridgeable differences in the way these two groups relate to e-learning processes that aim to promote algorithmic thinking. Our findings also emphasize the key importance of some motivational principles in facilitating algorithmic thinking: the principle of moderate and progressive challenge, the principle of gradual shift from concrete to abstract and the principle of genuine active involvement. © 2014 John Wiley & Sons Ltd.


Mako Z.,Sapientia University
Fuzzy Sets and Systems | Year: 2012

The construction of the membership function of fuzzy intervals is an important problem in vagueness modeling. The preservation of the shape of fuzzy sets during the addition is a natural requirement in practical computation. The LR-fuzzy intervals introduced by Dubois and Prade, satisfy this requirement if the addition is based on the nilpotent t-norm, generated by L or R shape functions. The shortcoming that not any LR-fuzzy interval has an opposite (inverse related to shape-preserving t-norm-based addition), can be solved, if the set of LR-fuzzy intervals is isomorphically included in an extended set, and this extended set forms a group with respect to shape-preserving t-norm-based addition. In this paper we construct the extended set of these LR-fuzzy intervals. We also show that the extended set is a real vector space with scalar product, and the modal intervals can be considered as the elements of this extended set. Finally, we present the algebraic form of LR-fuzzy intervals and the associated application. © 2012 Elsevier B.V.


Katai Z.,Sapientia University
ITICSE 2014 - Proceedings of the 2014 Innovation and Technology in Computer Science Education Conference | Year: 2014

The "2013 Best Practices in Education Award" (organized by Informatics Europe) was devoted to initiatives promoting Informatics Education in Primary and Secondary Schools. We briefly present the AlgoRythmics project (part of one of the winning proposals), consisting of six "sorting- dances" and an online e-learning tool which effectively exploits the didactical value of the dance-choreographies. Copyright © 2014 ACM.


Katai Z.,Sapientia University
ITICSE 2014 - Proceedings of the 2014 Innovation and Technology in Computer Science Education Conference | Year: 2014

The issues of Intercultural education (IcE) and Computer Science (CSE) education are of paramount importance in the twenty-first century. In this paper we describe a sweeping initiative to infuse cultural diversity in CSE through art-based pedagogical tools. We present an online e-learning environment that has the potential to equally promote both IcE and CSE. The folkdance choreographies we have created illustrate, on the one hand, basic CS concepts (six different sorting algorithms) and, on the other hand, the cultural diversity of Transylvania (Romania). Our "ALGO-RYTHMICS: science and art without ethnic borders" project also illustrates how the concept of 'unity-in-diversity' can be implemented in a science educational context: multicultural artistic performances promoting the cause of universal science. The study we performed revealed possible difficulties CS teachers may face when they are presenting scientific content in culturally diverse contexts (especially in regions with cultural tension). Research results revealed that students' culture related concepts and feelings may even influence the way they relate to the scientific content. Copyright © 2014 ACM.


Gabudean A.M.,Babes - Bolyai University | Biro D.,Sapientia University | Astilean S.,Babes - Bolyai University
Nanotechnology | Year: 2012

Surface-enhanced Raman scattering (SERS) nano-tags are of increasing interest in biomedical research as viable alternatives to bio-imaging techniques based on semiconductor quantum dots or fluorescent molecules. In this work, we fabricate silica-coated gold nanorods (AuNRs) encoded with two molecular labels to operate as highly effective spectroscopic nano-tags in near-infrared SERS (NIR-SERS) and surface-enhanced resonance Raman scattering combined with metal-enhanced fluorescence (SERRS-MEF), respectively. Specifically, a non-fluorescent molecule with strong affinity for a gold surface (para-aminothiophenol, p-ATP) and a common dye (Nile Blue, NB) with lower affinity have been successfully tested as NIR-SERS nano-tags under laser excitation at 785nm. Moreover, as a result of designing AuNRs with a plasmon resonance band overlapping the electronic absorption band of the encoded NB molecule, a dual SERRS and MEF performance has been devised under resonant excitation at 633 nm. We explain this result by considering a partial desorption of NB molecules from the metal surface and their trapping into the silica shell at favorable distances to avoid quenching and enhance the fluorescence signal. Finally, we prove that the silica shell prevents the desorption or chemical transformation of p-ATP into p,p-dimercaptoazobenzene species, as previously noticed, thus providing a highly stable SERRS signal, which is crucial for imaging applications. © 2012 IOP Publishing Ltd.


Balog A.,Yale University | Balog A.,Sapientia University | Schmitz O.J.,Yale University
Journal of Evolutionary Biology | Year: 2013

We conducted field surveys and experiments to evaluate the hypothesis that predation is an important driving factor determining the degree of coexistence between red and green morphs of the pea aphid Acyrthosiphon pisum. Theory suggests that the different colour morphs are differentially susceptible to natural enemies and selection by predation which in turn leads to variable relative abundances of red and green morphs among host plants across landscapes. Our field surveys on pea and alfalfa revealed, however, that the colour morphs tended to coexist closely in a ratio of one red to three green aphids across fields with different host plant monocultures. Experimentation involving manipulation of the relative abundances of the two colour morphs on host plants pea and alfalfa with and without predator presence revealed that red morphs had higher or same fitness (per capita reproduction) than green morphs on both pea and alfalfa only when in the proportion of one red/three green proportion. Moreover, experimentation evaluating predator efficiency revealed that red morphs are safest from predation when in a 1 : 3 ratio with green morphs. These results suggest that in addition to predation selection effects, red morphs may behaviourally choose to associate with green morphs in a narrow 1 : 3 ratio to maximize their fitness. This evidence, along with existing published data on red and green morph anti-predator behaviour indicates that a 1 : 3 red and green morph coexistence ratio is driven by a balance between predation pressure and behavioural assorting by red morphs across landscapes. In this way predators may have ecological-evolutionary consequences for traits that affect the colour morphs' proportion and tolerances to selective pressure. © 2013 European Society For Evolutionary Biology.


Salamon J.,Sapientia University
Journal of Global Optimization | Year: 2010

In this paper we introduced new definitions of vector topological pseudomonotonicity to study the parametric vector equilibrium problems. The main result gives sufficient conditions for closedness of the solution map defined on the setof parameters. The Hadamard well-posedness of parametric vector equilibrium problems is also analyzed by using the new definitions of vector topological pseudomonotonicity. © Springer Science+Business Media, LLC. 2009.


Gabudean A.M.,Babes - Bolyai University | Biro D.,Sapientia University | Astilean S.,Babes - Bolyai University
Journal of Molecular Structure | Year: 2011

In the present work, we study the adsorption of p-aminothiophenol (p-ATP) on gold nanorods (GNRs) using localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering (SERS) spectroscopies, as function of molecular concentration and pH values in solution. The LSPR spectra reveal the adsorption of p-ATP molecules onto the ends of GNRs. We address the intriguing case that has recently emerged in SERS literature regarding the interpretation of p-ATP SERS spectrum. Apart from typical electromagnetic bands of p-ATP, the aggregation of GNRs at basic pH revealed the appearance in SERS spectra of some extra bands, which can be assigned to the formation of p,p′- dimercaptoazobenzene (DMAB) through chemical transformation of p-ATP on metallic substrates. We correlate the SERS results with theoretical simulations of electromagnetic enhancement of Raman signal for individual and assembled GNRs by employing the Finite-Difference Time-Domain (FDTD) method. © 2010 Elsevier B.V. All rights reserved.

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