Vilnius University Institutional Repository

    Agent nouns in Latvian

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    Defining Belarusian tourists’ segment by the example of Vilnius as their destination

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    The paper is devoted to the analysis of the Belarusian tourist market on the example of Vilnius as a tourism destination. The main objectives of the article are: 1) to identify the dynamics of inbound tourist arrivals from Belarus to Lithuania for 2008–2013 and 2) to define preferences of tourists from Belarus and the main target audience on the Belarusian tourist market. The research has been conducted using such methods as secondary statistical data analysis of the main inbound tourism indicators and a survey using an online questionnaire. The paper has revealed that tourist arrivals from Belarus to Lithuania have been constantly growing, making up 1,045 million in 2013, which corresponds to 19.8% of all tourists that visited Lithuania that year. The empirical research has also found out that the prospective consumer of tourist services provided in Vilnius is a Belarusian aged 26–45, married, employed, with the average monthly income 501–1000 euro, has children, has been to Vilnius more than 4 times, prefers individual travelling, usually travels with family, visits Vilnius for shopping, events, excursions and transit purposes, stays in Vilnius for 2 days and spends about 340 euro. Taking into consideration the mentioned facts, the paper concludes that the development of marketing activities specifically tailored to the needs of Belarusian tourists will help to increase tourist arrivals and tourists’ expenses

    Economic impacts of EU-Belarusian

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    The main goal of the research is to assess the efficiency of Belarus–EU trade and to develop an econometric model to find out which goods Belorus should export in order to ensure its GDP growth. Authors have made an analysis of the main trade theories, reviewed the common EU trade policy, determined a relationship between Belarusian trade in goods with the EU and its economic growth, studied the consequences of the potential free trade agreement with the EU. The research used secondary data that have been analysed by means of a system of indicators, the matrix method, and regression correlation analysis. The analysis revealed that the trade balance between Belarus and the EU in most years has been negative, that the degree of trade concentration between Belarus and the EU is low, and that trade between the two parties has both intra-industry and inter-industry features. The econometric model has revealed a negative impact of the Belarusian export of agricultural products and iron and steel on its GDP growth rate. The study has also shown that so far it is difficult to forecast the timelines and consequences of Belarus–EU free trade agreement

    Business intelligence in the process of decision making: changes and trends

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    The concept of business intelligence has drawn substantial attention of both academicians and practitioners. As one of the fastest developing business application areas, business intelligence has also created a trail of confusion regarding its role, potential, sources of value creation. This study aimed at elucidating the role of business intelligence in the near future through the analysis of the current research and practical trends. The current prevailing trends in business intelligence technologies and systems are mobile business intelligence, location intelligence, software as a service, big data and predictive analytics. The paper points out that human factors in business intelligence are often underestimated, while a thorough consideration of their role should create additional ground for effective business intelligence applications. Some of the important considerations regarding human factors, such as support of problem-solving patterns and an efficient coordination of business intelligence activities, are presented

    The euroization of Lithuania and Poland: a comparison

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    Usually, euroization is connected with the necessity of passing through not easy to fulfil and to maintain the Maastricht Treaty criteria and to accept (à) priori a definite course of resigning from the national currency. Upon fulfilling the required adjustment periods of euro adoption, the European law forces a total departure from the national currency. This process is subjected to a solid supervision and control of the EU organs. Additionally, the Maastricht Treaty obliges to introduce the euro when a country is in a good economic condition, confirmed by the fulfilment of nominal convergence criteria. In such a situation, the common currency adoption must be (or should be) always interpreted as a proof of a stable economic development and abilities of keeping such parameters in the future. However, in case of euroization accomplished with omission (or even with infringing) the Treaty, there is no necessity of complementing any European law duties, and especially there is no obligation of totally resigning the national currency. Such kind of euro adoption means not a full but a partial euroization, which can appear in a very difficult situation in country`s economy or when currency independence is not safe and profitable. Resignation from the national currency is like an act of desperation, or at least it is forced by the lack of the abilities to manage the economic problems. The purpose of this publication is to show euroization as state (partly also as process), particularly on the examples of Lithuania and Poland. It obviously it does not seem new, but many changes in the world economy (with special regard to the crisis hurting the European Union) and the lower enthusiasm for joining the Euroland (euro zone) show the need to consider such a problem

    Elektrocheminis Cu-Zn-Sn pirmtako nusodinimas ir Cu2ZnSnSe4 saulės elemento formavimas

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    In this study Cu2ZnSnSe4 (CZTSe) solar cells have been formed by selenizing electrochemically deposited Cu-Zn-Sn (CZT) precursor. Two approaches have been presented for forming CZT precursor: a) co-deposition of Cu-Zn-Sn and stacked Cu, Sn, Zn layer deposition using flow cell. Deposition parameters (deposition potential, current density, electrolyte composition, flow rate) were optimized in order to obtain well-adherent to Mo substrate, uniform in thickness and composition CZT precursor layers. The detailed SEM combined with EDX investigation of CZT precursor morphology, cross-section and composition have been carried out. CZT precursors were preliminary annealed at 200 – 350 °C temperature in order to reduce film porosity and to form intermetallic compounds. The XRD and XRD in situ methods have been applied to investigate the formation of intermetallic compound of as-deposited and preheated CZT precursors. The influence of initial CZT composition and selenization conditions (temperature, duration, amount of Se) on the CZTSe morphology, phase composition and CZTSe solar cell performance has been investigated. Cu-poor, Zn-rich composition and preheating of CZT precursor was necessary to obtain relatively efficient CZTSe solar cells

    Optinio ZnMgRE kvazikristalų atsako tyrimai

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    The main goal of the dissertation was to reveal the electronic structure of ZnMgRE (RE = Y, Ho, Er) quasicrystals by investigations of their optical response. The thesis comprises experimental X-ray diffraction (XRD) and optical spectroscopy studies of the quasicrystals, a construction of their electron subsystem model, and a theoretical description of their optical response. The XRD studies were carried out to determine the reciprocal quasicrystalline lattice vectors, which define the atomic potential field acting on an electron subsystem. The optical spectroscopy studies were carried out by the combined spectroscopic ellipsometry and reflectance spectroscopy technique, based on a suggested anchor-window method. High-accuracy ZnMgRE optical conductivity spectra were recorded in the wide, 0.01 – 6 eV, spectral range. The model of ZnMgRE electron energy spectrum, previously suggested for an interpretation of experimental ZnMgRE photoemission spectra, was developed. The nearly-free-electron gas model of independent intersections was formulated in the extended zone presentation. A scheme of the theoretical optical conductivity calculations was extended to account for various positions of the Fermi level with respect to a pseudogap. The experimental ZnMgRE optical conductivity spectra can be reproduced in detail by theoretical calculations performed within the framework of the suggested electron energy spectrum model. The set of the electron energy spectrum parameters determined from analysis of the optical data predicts actually the same structure of the Fermi level-vicinity electron energy spectrum, as was previously predicted from an analysis of photoemission data. The electron subsystem in ZnMgRE quasicrystals maintains the nearly free electron gas character. The energy spectrum of electrons in a vicinity of the Fermi level is determined by the Fermi surface intersections with (222100) and (311111) families of Bragg planes. The optical response of ZnMgRE quasicrystals, as of other metallic compounds, is determined by the intraband Drude-type and interband optical transitions. The intraband transitions contribute to the total optical conductivity with the relative spectral weight of about 10 %. The Drude relaxation times are of about 0.14–0.4 10^(-14) s. The intersections of the Fermi surface with Bragg planes lead to an essential increase of the optical mass in quasicrystals, as compared to the usual crystalline metals. The ZnMgRE optical mass is of the order of 10 m0. The interband ZnMgRE optical conductivity is predominantly due to the optical transitions across 222100 and 311111 pseudogaps. Their relative spectral weight is of about 80 %. An influence of the low structure-factor Sg pseudopotentials on the optical response of ZnMgRE quasicrystals was revealed. The relative spectral weight of the low-Sg contribution is of about 10 %

    Efficient encryption and digital signature schemes

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    This submission called “Efficient encryption and digital signature schemes” consists of three parts. I. In Part I theoretical analysis of popular public key cryptosystems RSA (Rivest, Shamir, Adleman) with security based on the large integer factorization problem and ElGamal with security based on the discrete logarithm problem, along with new cryptographic primitive termed as "signcryption" proposed by Y. Zheng which simultaneously fulfills both the functions of digital signature and public key encryption in a logically single step, and with a cost significantly smaller than that required by "signature followed by encryption" using popular public key cryptosystem composition is done. For the completeness of analysis description of supplemental algorithms and functions such as AES block cipher, SHA hash functions, HMAC keyed hash function is present. II. In Part II the results of the practical implementation done in Python programming language are analyzed. Effectiveness is described by two factors: 1. Total computation time of signing – encryption – decryption – verification operations; 2. Communication overhead – signed and encrypted message length increase compared to the original plaintext. III. In Part III two effective Signcryption implementation algorithms are proposed: secret sharing without threshold and (k, n) threshold schemes. Results of analysis prove Signcryption being secure and extremely effective signature and encryption cryptosystem. It has very low requirements for the computational power as well as provides almost no data expansion. These properties make it perfect solution for battery-powered small devices such as smart cards, mobile phones and personal digital assistants (PDAs) and applications operating in resource-constrained environment such as contactless wireless identification tokens

    Growth of GaᵧIn₁₋ᵧAs₁₋ₓBiₓ layers by molecular beam epitaxy for optoelectronic applications

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    Bismuth-containing compounds are attractive due to the possibility of usage as emitters or detectors operating in the near- and mid- infrared spectrum region, solar cells, components of spintronic devices and terahertz (THz) frequency systems. THz time-domain spectroscopy systems based on GaAs are currently the most common, but they are large in size and expensive. They could be replaced by more compact and rather cheaper systems, operating in the range of telecommunication wavelengths (1−1.5 µm), if the components – emitters and detectors – would be produced from GaᵧIn₁₋ᵧAs₁₋ₓBiₓ compound. Orienting to the development of mid-range infrared radiation detectors, GaᵧIn₁₋ᵧAs₁₋ₓBiₓ compounds can also be useful because it is known that it is possible to achieve compounds in which the optical absorption edge moves up to 6 μm. Optimization of the growth conditions of GaᵧIn₁₋ᵧAs₁₋ₓBiₓ layers is described in this dissertation. Bismide-based THz components for 1.55 µm spectroscopic systems were made and compact THz time-domain spectroscopy system was fabricated. GaᵧIn₁₋ᵧAs₁₋ₓBiₓ layers with the absorption edge up to 2.3 µm were grown in this dissertation; the investigation of the influence of post-annealing process on the properties of quaternary compounds has showed the good prospective of their applications in optoelectronic devices
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