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The work is devoted to the study of possible predictors of atrial fibrillation (AF) recurrence after interventional procedures. Purpose: to study the echocardiographic predictors of AF recurrence in patients with arterial hypertension after pulmonary veins catheter ablation.

The article develops a methodological approach to the assessment of socio-economic development of the Chuvash Republic, which allows to consider the factors with heterogeneous metrics. The scientific novelty of the study lies in the combination of methods used and the sequence of stages implemented: (1) index analysis of thirty-two indicators divided into seven macro-regional blocks (income, labor, business, ecology, social, prospects, finance); (2) development of formulas for each of them and calculation of integral indicators characterizing their dynamics; (3) development of a formula to determine the rate of socio-economic development; (4) one hundred graphs for forecasting socio-economic development were constructed; (5) thirty-one legal and regulatory acts were analyzed and the dependence by year between the indicator of the rate of socio-economic development developed by the authors and the number of legal and regulatory acts implemented in the country and the region was revealed; (6) a refined classification of the rate of socio-economic development was proposed. Having determined the current situation (2020 is a state close to sustainable—the rate of 99.5%, respectively), and based on the calculated forecast values of the rate of socio-economic development of the Chuvash Republic, it is possible to influence this process depending on the objectives for the medium term, taking the necessary regulatory legal acts, aimed at financing specific macroeconomic blocks. This methodical approach is a universal calculation tool and has great potential for further research. It can be used to assess not only the impact of certain indicators on socio-economic development, it is also applicable to other sectors and spheres of activity.

The article examines the ideas about space that have developed in Russian historical and song folklore. In the poetics of the epic song genres of Russian folklore, namely, in epics and historical songs, space plays an important role, defining “one’s own” and “alien” (“other”) worlds within one of the main mythologemes. Natural space (forests, rivers, seas, mountains, caves, etc.) mark the “other” world; cities — “one’s own” (“human”) at the mythological level. Historical ideas about space arise in heroic ballads, which, according to the concept of V. Ya. Propp, are an example of the state epic. Accordingly, the “own”/“foreign” mythologeme is already determined by the content “Russian world”/“enemy world” and is filled with real toponyms. In historical songs, there is a fundamental replacement of the former generalized type of historicism (epic) by concrete historicism, which affects the toponymic system. A number of examples raise the question of the correspondence or non-correspondence of the toponym in epics and historical songs to geographical reality. With regard to the Caspian Sea toponym, the almost complete absence of connections between the geographical name and the real geographical object is emphasized. The notions of the Baltic Sea, as well as of the towns of the Neva-Baltic space (Shlisselburg, Derpt, Revel), turn out to be more firmly connected with real geography. Shifts in the naming of geographical objects are specially considered: Khvalynsk/Caspian Sea; Varangian/Virian/Baltic Sea; Oreshek/Shlisselburg; Yuryev/Dorpat; Kolyvan/Revel.

Monolayer transition-metal dichalcogenide (TMD) semiconductors exhibit strong excitonic effects and hold promise for optical and optoelectronic applications. Yet, electron doping of TMDs leads to the conversion of neutral excitons into negative trions, which recombine predominantly non-radiatively at room temperature. As a result, the photoluminescence (PL) intensity is quenched. Here we study the optical and electronic properties of a MoS2/WSe2 heterostructure as a function of chemical doping by Cs atoms performed under ultra-high vacuum conditions. By PL measurements we identify two interlayer excitons and assign them to the momentum-indirect Q-Gamma and K-Gamma transitions. The energies of these excitons are in a very good agreement with ab initio calculations. We find that the Q-Gamma interlayer exciton is robust to the electron doping and is present at room temperature even at a high charge carrier concentration. Submicrometer angle-resolved photoemission spectroscopy (micro-ARPES) reveals charge transfer from deposited Cs adatoms to both the upper MoS2 and the lower WSe2 monolayer without changing the band alignment. This leads to a small (10 meV) energy shift of interlayer excitons. Robustness of the momentum-indirect interlayer exciton to charge doping opens up an opportunity of using TMD heterostructures in light-emitting devices that can work at room temperature at high densities of charge carriers.

This work presents a facile sol–gel method for the deposition of ZnO and ZnO:Mg films. The films are spin coated on silicon and quartz substrates. The impact of magnesium concentrations (0, 0.5, 1, 2 and 3 wt%) and post-annealing treatments (300–600 °C) on the film’s structural, vibrational and optical properties is investigated. Undoped ZnO films crystallize in the wurtzite phase, with crystallite sizes ranging from 9.1 nm (300 °C) to 29.7 nm (600 °C). Mg doping deteriorates the film crystallization and shifting of 002 peak towards higher diffraction angles is observed, indicating the successful incorporation of Mg into the ZnO matrix. ZnO:Mg films (2 wt%) possess the smallest crystallite size, ranging from 6.2 nm (300 °C) to 25.2 nm (600 °C). The highest Mg concentration (3 wt%) results into a segregation of the MgO phase. Lattice constants, texture coefficients and Zn–O bond lengths are discussed. The diminution of the c lattice parameter is related to the replacement of Zn2+ by Mg2+ in the ZnO host lattice. The vibrational properties are studied by Fourier transform infrared (FTIR) spectroscopy. IR lines related to Mg–O bonds are found for ZnO:Mg films with dopant concentrations of 2 and 3 wt%. The optical characterization showed that the transmittance of ZnO:Mg thin films increased from 74.5% (undoped ZnO) to about 89.1% and the optical band gap energy from 3.24 to 3.56 eV. Mg doping leads to a higher refractive index compared to undoped ZnO films. The FESEM (field emission scanning electron microscopy) technique is used for observation of the surface morphology modification of ZnO:Mg films. The doped ZnO films possess a smoother grained surface structure, opposite to the wrinkle-type morphology of undoped sol–gel ZnO films. The smoother surface leads to improved transparency of ZnO:Mg films.

The structural, vibrational, optical and morphological properties of ZnO:N:F films, obtained by the sol-gel method, were investigated. The effect of single (fluorine, nitrogen) and F, N co-doping and thermal treatments (300–600 °C) on the properties of ZnO films was analyzed. X-ray Diffraction (XRD) revealed that ZnO:N:F films crystallized in a polycrystalline wurtzite structure. F and N incorporation changed lattice parameters, crystallite sizes, texture coefficients (TC) and residual stress. TC (002) of ZnO:N:F films increased with annealing, reaching 1.94 at 600 °C lower than the TC (002) of ZnO and ZnO:N films. The shifting of the characteristic absorption bands and/or the appearance of new IR lines were detected for ZnO:N:F samples. The highest transmittance (90.98%) in the visible spectral region was found for ZnO:F films. ZnO:N:F films possessed optical transparency up to 88.18% and their transmittance decreased at the higher annealings. The optical band gap (Eg) values of ZnO:N:F films were changed with fluorine and nitrogen concentrations. The formation of the wrinkle-like structures on the surface of ZnO and ZnO:N films was depicted in Field Emission Scanning Electron Microscopy (FESEM) images. The F, N dual doping modified ZnO morphology and suppressed wrinkle formation.

The article describes the morphological features and mineral composition of two amethyst geodes from the exposition of Moscow State University’s mineralogical gallery “Nature’s Art in Stone”, based on the Primo Rovis collection. The article presents data from the studies of the phase composition of the geodes by powder X-ray diffraction (XRD) and micro X-ray spectral (XRD) analyses, and contains microphotographs. The mechanism of mineral phase crystallization of the described geodes is proposed.

The relevance of this study is tied to the fact, that more effective application of export potential represents a major step towards the integration of Latvia’s economy into a unified economic framework with other European Union countries. In addition, the lack of a generally accepted methodology for assessing export potential increases the significance of these studies from a methodological point of view. The purpose of this study is to analyse the trends in Latvian exports and assess the possibilities of increasing the volume of exports of goods to the EU countries. This study applied quantitative and qualitative methods of analysis, analysis of statistical data, methods for assessing the intensity, complementarity of trade between two countries and the potential for exporting Latvian goods to EU countries. The study identifies the countries and categories of goods where Latvian trade potentialto EU can be increased. The authors of the article propose criteria for determining possibility of increasing the export of various groups of goods. The paper may be of interest to all export transaction participants, including manufacturers, merchants, and professional associations. The export expansion assessment method applied by the authors may be adopted by exporting companies to identify groups of goods that have export growth reserves.

ZnO/Ag/ZnO nanolaminate structures were deposited by consecutive RF sputtering at room temperature.The optical transparency, sheet resistance, and figure of merit are determined in relation to the deposition time of Ag and to the film thickness of the ZnO top layer. An improved transmittance has been found in the visible spectral range of the ZnO/Ag/ZnO structure compared to ZnO multilayers without Ag. High transmittance of 98% at 550 nm, sheet resistance of 8 Ω/sq, and figure of merit (FOM) of 111.01 × 10−3 Ω−1are achieved for an optimized ZnO/Ag/ZnO nanolaminate structure. It is suggested that the good optical and electrical properties are due to the deposition of the discontinuous Ag layer. The electrical metallic type conductivity is caused by planar located silver metal granules. The deposition of a discrete layer of Ag nano-granules is confirmed by atomic force microscopy (AFM) and cross-section high-resolution transmission electron microscopy (HRTEM) observations.

This article discusses the use of alternative inexpensive adsorbents – wastes from the metal production - red mud (RM) and black nickel mud (BNM) and their sorption efficiency in 3,5-dichlorophenol removal. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and chlorine atoms. The effects of adsorbent dose, contact time, and temperature on sorption process were monitored. The results showed that the optimal conditions to achieve the highest sorption efficiency of 3,5-dichlorophenol were reached with the use of black nickel mud at the amount (2.0 g), sorption time (1 hour) and at increased temperature (45 °C). The sorption efficiency under these conditions was 87.99 %. With increasing sorption time, the sorption efficiency decreased and desorption occurred. The same behaviour was observed using red mud of the same amount (2.0 g) at the same temperature (45 °C); however, after 1 hour, sorption efficiency was slightly reduced (85.16 %) compared to black nickel mud. Anyway, both of used materials are suitable for the use as alternative sorbents of 3,5-dichlorophenol under suitable conditions.

Buffaloes from intensive (farm 1 - Fm1; 438 normal, 115 short lactations) and pasture (farm 2 - Fm2; 330 + 58 lactations) system were assigned to study lactation curve via ANOVA (LSMLMW and MIXMDL) per each 10-day period (“tenday”), as well as overall (PI1) and post-peak (PIP) persistency. Greatest is the effect of parity and season, also of year on 2nd-12th tenday. Persistency is affected by parity, year and season of calving, and especially by peak month and DIM (P≤0.001). The curves showed peak averagely at 2nd tenday in both herds. Compared to the buffaloes on pasture, Fm1 has significantly lower milk in initial two and in 15th to 21st tendays, defining slower decline to mid-lactation and faster after that. These differences in the curves predetermine a non-significant difference in PI1 between Fm1 and Fm2 (0.932 and 0.940) and a significant but still small superiority in PIP of Fm2 (0.893) over Fm1 (0.880). The lactations below 210 days are 17.8%, persistency being 0.859 to 0.742, and peak by 17 to 32% worse than normal lactation. Long and very long lactations’ persistency is 0.923 and 0.950. Only very long lactations have а typical curve – 4th tenday peak, by 10% lower than normal lactation., Бяха включени биволици от интензивна (Fm1 – 438 нормални и 115 къси лактации) и пасищна (Fm2 - 330 + 58 лактации) технология на отглеждане, за проучване на лактационната крива чрез ANOVA (LSMLMW и MIXMDL) за всяка 10-дневка, както и на общото (PI1) и след-пиково (PIP) постоянство. Най-значим е ефектът на поредната лактация и сезона,, както и на годината за 2-ра–12-та десетдневка. Постоянството се влияе от поредната лактация, годината, сезона, и особено от пиковия месец и дойните дни (P≤0.001). Пикът е средно през 2-ра десетдневка в двете стада. В сравнение с биволиците на паша, Fm1 има достоверно по-ниска млечност в първите две и в 15та–21ва десетдневка, дефинирайки по-бавен спад до средата на лактацията и по-бърз след това. Тези разлики в кривите предопределят недостоверна разлика в PI1 между Fm1 и Fm2 (0.932 и 0.940) и и малко но достоверно превъзходство в PIP на Fm2 (0.893) спрямо Fm1 (0.880). Лактациите под 210 дни съставляват 17,8%, като постоянството е от 0,859 до 0,742, а пика е със 17 до 32% по-нисък от нормалната лактация. Постоянството на дългите и много дългите лактации е 0,923 и 0,950. Само много дългите лактации имат типична крива – пик в четвърто десетдневие, с 10% по-нисък от нормалната лактация.

Introduction Allergic rhinosinusitis (AR) is a clinical manifestation of a type 1 hypersensitive reaction. A complex of reactions involving components of the immune system - cells, mediators, cytokines, neuropeptides, adhesion molecules etc., are involved in the manifestation of the disease symptoms. Aim To evaluate the role of some serum and local cytokines and IgE molecules in the pathogenesis of AR comparing results in patients and healthy controls. Material and methods The study was conducted at the Prof. Dr. St. Kirkovich University Hospital and Medical University, Stara Zagora, Bulgaria. Results A trend towards higher serum levels in patients with AR compared to controls was found for IL-4, but with no significant difference. In the group of AR patients, those with the intermittent form had higher, although with no significance, interleukin 4 (IL-4) levels in the lavage compared to those with the persistent form. In nasal lavage fluids a tendency towards higher IL-5 levels was found in intermittent AR patients compared to those with persistent AR. A slight trend towards significantly higher serum levels of IL-13 in overweight patients compared to those with normal weight was found. Conclusions Regardless of the obvious differences of the concentrations of the cytokines studied in our groups, oftentimes no significant difference is observed. More studies should be conducted in order to show the role of IL-4, -5, -13, and IgE in the pathogenesis and severity of the disease.

In our study, transparent and conductive films of NiOx were successfully deposited by sol-gel technology. NiOx films were obtained by spin coating on glass and Si substrates. The vibrational, optical, and electrical properties were studied as a function of the annealing temperatures from 200 to 500 °C. X-ray Photoelectron (XPS) spectroscopy revealed that NiO was formed at the annealing temperature of 400 °C and showed the presence of Ni+ states. The optical transparency of the films reached 90% in the visible range for 200 °C treated samples, and it was reduced to 76–78% after high-temperature annealing at 500 °C. The optical band gap of NiOx films was decreased with thermal treatments and the values were in the range of 3.92–3.68 eV. NiOx thin films have good p-type electrical conductivity with a specific resistivity of about 4.8 × 10−3 Ω·cm. This makes these layers suitable for use as wideband semiconductors and as a hole transport layer (HTL) in transparent solar cells.

This paper proposes results of the literature analysis of Intelligent Tutoring Systems (ITSs) from technological point of view. Exploring and classifying used architectures and technologies we outline important criteria for comparison of used intelligent technologies and it’s usefulness of for tutoring and learning and outline trends in the area of ITSs.

The intelligent tutoring systems (ITSs) are e-learning systems that apply artificial intelligence techniques to achieve a behavior, similar to teacher’s behavior during tutoring process. A significant number of ITSs have been developed during the last decade. In this paper we present our results of the analysis of valuable scientific sources, discussed usage of ontologies for development of knowledge models for ITSs. We present a general methodology for development of lower-cost ITSs, containing reusable components, and general classification of tutoring strategies to ensure dynamic selection of the best strategy by the tutor.

Many educational systems are focused predominantly on such an organization of the learning process to be uniform for all learners. This approach is not the best for many learners, especially for those with various difficulties or interests. Strategies for personalization and adaptation can increase the tutoring quality and ensure efficient learning for groups of learners with different needs, goals, or interests. Intelligent technologies can enable the personalization of the learning process. However, no one system can contain all the knowledge needed for all learners, so interoperability between e-learning systems is of greater importance. Standards are needed for ensuring interoperability, but they are not sufficient. This paper first analyzes and classifies sources for learning on the Internet. The findings help to develop a knowledge model needed for a personalized recommendation of web-based sources, complementary to the learning content that a well-organized intelligent educational system can propose to learners. Having in mind specifics of the ontologies needed for modeling the learning domain, a model of the ontological repository for storing ontologies that can be useful for building intelligent educational systems is suggested. We also discussed mapping problems between ontologies and modeling e-learning standards.

Introduction. The article discusses the relationship of the real economy and the credit sector. An attempt has been made to assess the financial consequences of the over-indebtedness of business entities and its impact on the state of the banking sector of the Republic of Belarus. Purpose. Based on a study of theoretical and applied aspects of the relationship between the real and financial sectors, to assess the impact of bank lending on the state and development of the economy of the Republic of Belarus and the financial consequences of the borrowing of business entities. Results. It has been established that there is a contradiction between the sectors, which is reflected in the fact that with the improved financial results of economic entities, there is an increase in credit risk in the banking sector, which is caused by many factors, including key lending and refinancing of loans. It was concluded that the growth is not due to the effective use of credit resources, but to excessive government intervention in the regulation of credit processes. Originality. It has been established that there is a contradiction between sectors, which is manifested in the fact that with the improving financial performance of business entities, there is an increase in credit risk in the banking sector, which is due to many factors, among which a key role is played by directed lending and refinancing of loans. It is concluded that the growth is caused not by the efficient use of credit resources, but by excessive government intervention in the regulation of credit processes. Conclusion. Studying the relationship between the real sector of the economy and the credit market, it was found that they are in contradiction, which is expressed in the fact that with the growth of financial results in the first, credit risk in the banking sector increases. This is due to excessive government interference in lending processes through direct lending, refinancing of loans, and the fact that the regulator recommends issuing loans to insolvent state enterprises. Excessive borrowing of the non-financial sector of the Belarusian economy, associated with the constant refinancing of credit debts, cannot be considered in the long term as a means of solving the problem of maintaining sustainable growth and can aggravate the situation not only in this sector, but also in the banking sector, which is the main supplier of financial resources.

The notion of contact algebra is one of the main tools in the region-based theory of space. It is an extension of Boolean algebra with an additional relation C, called contact. Standard models of contact algebras are topological and are the contact algebras of regular closed sets in a given topological space. In such a contact algebra we add the predicate of internal connectedness with the following meaning—a regular closed set is internally connected if and only if its interior is a connected topological space in the subspace topology. We add also a ternary relation $$\vdash $$ meaning that the intersection of the first two arguments is included in the third. In this paper the extension of a Boolean algebra with $$\vdash $$ , contact and internal connectedness, satisfying certain axioms, is called an extended contact algebra. We prove a representation theorem for extended contact algebras and thus obtain an axiomatization of the theory, consisting of the universal formulas, true in all topological contact algebras with added relations of internal connectedness and $$\vdash $$ .

Introduction. The natural productive forces of each region have remained unchanged for thousands of years. The nature of their use is changing. Analysis of the process of construction of the Volga-Don channel in the scientific thought of Russia in the 18th – mid 20th centuries allows us to determine: 1) the formation and evolution of projects of infrastructure economic reforms in scientific and public thought, 2) the political conditions and reasons leading to their implementation. Methods and materials. The authors use the principles of historicism and objectivity, analysis, synthesis, historical and genetic method, systematic approach. The construction projects of the Volga-Don channel were discussed in the works of A.G. Brikner, S.V. Bernshtein-Kogan, V.F. Gnucheva, I.I. Golikov, A.N. Minkh, V.V. Bulatov, M.M. Zagorulko. These works deal with different options of project implementation and the possibility of its use on the basis of concession. Analysis. The paper analyzes how in the scientific thought of Russia in the 18th – 20th centuries different projects of connection of the Volga and the Don by the channel were created. The research shows that attention of the scientific society and the state powers to this scientific and technical question increased in the periods of the great reforms – in the times of Peter I, Catherine the Great and in the time of the Soviet economic reforms of the 1920s-1930s. From the beginning of the 18th century and till the middle of the 20th century empirical data on this problem were accumulated. Results. On the one hand, for over two centuries the empirical data on the channel construction had been accumulated, the focus had being shifted from the one-scale consideration of this problem as a transport and military-political one to the complex research of the channel influence on geography, economy, nature of the region. On the other hand, the most important details of economic model had remained unchanged, and finally, the connection of the Volga and the Don was carried out by the decision of the State power, with the use of unfree labor and was funded by the State, i.e. in the same way as it was planned in the times of Peter I. I. O. Tyumentsev has worked out the key conception of the work, carried out the academic editing of the paper. A. L. Kleytman has analyzed scientific projects of the Volga-Don channel construction in the 18th – early 20th century. T. B. Ivanova has analyzed economic and technological projects of the Volga-Don channel construction in the Soviet times.

In this work, the feasibility of atomic layer deposition (ALD) to prepare tran sition metal (Ni-, Co- or Fe-) doped ZnO thin films have been studied. The effects of dopant on the structure, morphology and optical properties of films have been investigated by a number of various techniques: X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ellipsometry, UV–Visible spectroscopy, Fourier transformed infrared spectroscopy (FTIR). The effect of substrate (glass, Si with different conductivity type and orientation) on the morphology of layers has also been studied. All layers have a hexagonal wurtzite structure but the preferential orientation of crystallites depends strongly on the dopant. In the case of Ni-doping, the results unambiguously reveal the incorporation of Ni in ZnO lattice. NiO clusters are also possibly formed in Ni:ZnO layers which can explain the observed significant decrease of their transparency. The investigations imply that under the doping scheme and technological conditions used in this study Co and Fe are incorporated only in small amounts in ZnO. Co-doping improves the transparency of ZnO films. The possibility to deposit thin homogeneous films of transition metal (Ni-, Co- or Fe- ) doped ZnO by ALD method opens-up new frontiers for implementation of these materials in advanced electronic, magnetic or optical applications.

Two layer system from sputtered indium tin oxide (ITO) and gallium doped zinc oxide (Ga:ZnO, GZO) were studied for transparency in the visible electromagnetic range, reflectivity in the near infrared range, conductivity and valent band for a solar cells with quantum dots. The bi-layer coatings produced at optimized oxygen partial pressure, films thickness and surface roughness exhibit improved optical properties without worsening the electrical parameters, even if additional oxygen introduction during the reactive sputtering of the GZO. With an average optical transmittance of 91.3% in the visible range, average reflection and resistivity lower than 0.4 × 10−2 Ω.cm, these coatings are suitable for top electrode in the solar cells. The obtained results reveal that multilayered stacks of transparent ITO/Ga-doped ZnO coatings possess relatively low surface roughness (7–9 nm) and appropriate refractive index. The additional oxidation of GZO films induces modification of the film thickness and respectively of their optical performances.

The paper is devoted to the analysis of seismic input characteristics from the point of view of their importance for engineers. It is noted that the design input does not need to have an external resemblance to the real one but it must provide for some properties of real actions. The paper considers three groups of seismic input characteristics: kinematic, spectral and energy ones. The stability of the characteristics under consideration is analyzed within the seismic intensity on the MSK scale. Among all characteristics, peak acceleration, peak velocity, harmonicity coefficient, Arias intensity, and absolute cumulative velocity are highlighted. It is noted that the kinematic characteristics significantly depend on the prevailing accelerogram period, and many energy characteristics are stable within the seismic intensity under consideration and can describe it. It is noted that for calculating structures under the design earthquake action, the kinematic characteristics should be fundamental for the engineer, and for calculating structures under the destructive (maximum design) earthquake action, the energy characteristics are fundamental. Two new seismic input characteristics are introduced, which are based on the response spectrum of the work of plastic deformation forces and on the structure damage spectrum.

The article develops the author’s methodology for assessing the rates of socio-economic development and their forecasting in the Russian Federation, which makes it possible to consider factors with heterogeneous metrics. For this, an index analysis of thirty-two indicators divided into seven macro-regional blocks (income, labor, business, ecology, society, prospects, finance) was carried out, integral indicators were calculated that characterize their changes and the pace of socio-economic development of the Russian Federation was determined. Further, using the means of mathematical modeling, a multifactorial mathematical model was built and tested in real-time, which makes it possible to obtain a high-quality predicted result. Based on the forecasts obtained, it can be stated that it is necessary to adjust certain indicators that actively influence the pace of development, which is a mathematical justification for making managerial decisions when developing strategies and programs related to socio-economic progress in the Russian Federation.

Paper The goal of search engines is to return accurate and complete results. Satisfying concrete user information needs becomes more and more difficult because of inability in it complete explicit specification and short comes of keyword-based searching and indexing. General search engines have indexed millions of web resources and often return thousands of results to the user query (most of them often inadequate). To increase result’s precession, users sometimes choose search engines, specialized in searching concrete domain, personalized or semantic search. A grand variety of specialized search engines may be found (and used) in the internet, but no one may guarantee finding of existing in the web and needed for the concrete user resources. In this paper we present our research on building a meta-search engine that uses domain and user profile ontologies, as well as information (or metadata), directly extracted from web sites to improve search result quality. We state main requirements to the search engine for students, PHD students and scientists, propose a conceptual model and discuss approaches of it practical realization. Our prototype metasearch engine first perform interactive semantic query refinement and then, using refined query, it automatically generate several search queries, sends them to different digital libraries and web search engines, augments and ranks returned results, using ontologically represented domain and user metadata. For testing our model, we develop domain ontologies in the electronic domain. We will use ontological terminology representation to propose recommendations for query disambiguation, and to ensure knowledge for reranking the returned results. We also present some partial initial implementations query disambiguation strategies and testing results.

There is a lot of research on ontology mapping. The importance of ontology alignment quality is obvious in the context of usage of systems of mapped ontologies in many applications. The assessment of the quality of the alignments or mapping algorithms have many dimensions. In this paper we will analyze ontology mapping evaluation, classify approaches and problems and discuss its applicability in various contexts.

Mapping tacks may require mapping ontologies, labelled in various natural languages. OAEI proposes test sets for evaluation of alignments mainly in English. Only MultiFarm track in conference domain is adapted for evaluation of alignments in ten natural languages and Bulgarian language is not included. In this paper we propose and discuss an adaptation of MultiFarm test set for evaluation of alignment between Bulgarian language - labelled ontologies and alignments of multilingual ontologies.

Thin films of ZnO:Ga2O3 (ZGO) were deposited by radio frequency (RF) sputtering at voltages of 0.5, 0.9 and 1.1 kV. The films were studied with respect to their suitability in flexible piezoelectric nanogenerators. The analysis of the spectroscopic and microscopic results showed that piezoelectric features were revealed for the films grown at all sputtering voltages, but the most favorable morphology in terms of low roughness was achieved at 1.1 kV. The effect of the sputtering voltage on the films crystallinity and lattice strain was studied. It was found that the increasing sputtering voltage promoted the films crystallization. Additionally, the presence of oxygen vacancies in the piezoelectric films was negligible as it is not a major factor affecting their performance. The electrical measurements of the Ag/ZnO:Ga2O3/Ag harvester on a flexible substrate in the low-frequency range showed a piezoelectric voltage of 414 mV, a current of 10.4 &micro, A and an electric power output of 1.4 &micro, W at a mass load of 100 g. These results were achieved by a simple architecture of a single piezoelectric layer with a relatively small size of 3 cm2 and small piezoelectric film thickness (600 nm) containing lead-free material. It was proven that the sputtered ZGO films are suitable for energy harvesting elements and their performance could be tuned by the sputtering voltage. Another possible application of the proposed device, excluding low-frequency vibrational harvesting, could be a pressure sensor or strain gauge, due to the good linearity of the electrical parameter dependences on the strain.

Many ontologies have been developed recently, and evaluation is important for researchers or users when searching ontologies needed in their work. Ontology evaluation also is important phase of ontology development, refinement or evolution process. Automatically-developed ontologies as a result of ontology learning also need from evaluation. So, ontology evaluation is important both for selecting ontologies, meeting some requirements, and as a part of ontology life cycle. In this paper we propose deep analysis of ontology evaluation and discuss how multilingualism affects ontology evaluation. We classify ontology evaluation approaches, methods and metrics according to several dimensions. Our analysis and conclusions will be helpful for development of good ontologies and for finding or selection of needed ontologies.

Much research in the area of e-learning systems today is focused on personalization and adaptivity, but only a few of the proposed systems are intended for students, having learning disabilities. These learners are significant amount of all learners (children, having some dyslexia symptoms are between 10% and 20% of all children). Dyslexia symptoms can be specific for different learners and can require specific organization of learning. All the experts in learning say that suitable learning is a key for achieving excellent results for these learners.We made extensive study on the relevant theories intended for better understanding of the requirements of an e-learning for people, having learning disabilities and existing frameworks or tools for people with dyslexia. As a result we propose a knowledge model for developing, describing, searching and recommending personalized learning resources in the web for learners, having dyslexia learning disability. We also propose agent-based software architecture, that manage and use implemented knowledge for supporting leaning resource development, searching, ranking according to specified criteria and recommendation of these resources to dyslexic learners.

Bi-layer coatings from sputtered indium tin oxide (ITO) and gallium doped zinc oxide (Ga:ZnO) were investigated for transparency in the visible range of the electromagnetic spectrum, optical rejection ability in the near infrared spectrum and conductivity for the novel quantum dot based solar cells. The multilayer stack with optimized films thickness and surface roughness exhibit improved optical properties without to worsen the electrical ones, especially after additional oxidation during reactive sputtering of the metal-oxides. With an average optical transmittance of 90.7% over the visible region, average optical rejection greater than 65 % in the infrared range and resistivity lower than 100 Ω.cm, this coating is good candidate for front panel in CdS/ZnS core-shell quantum dots based solar cells. The efficiency of the cell increased with approximately 3 % as compared to the case with ITO only electrode. The results might be ascribed to the relatively low surface roughness and to the narrowed transmittance spectrum after ITO/Ga:ZnO interface has been established, targeting absorption of visible light only.