1,721,012 research outputs found
Nuotolinių studijų vartotojų poreikių analizė
Get PDFNuotolinės studijos šiuo metu tampa viena populiariausių studijų formų Lietuvoje ir pasaulyje. Besivystant informacinėms ir komunikacinėms technologijoms daugelis žmonių studijuoja neatsitraukdami nuo savo darbo vietų. Tokiame studijų procese dalyvauja skirtingi vartotojai: studentai, dėstytojai, nuotolinių modulių kūrėjai, auditoriai, virtualaus mokymo aplinkų administratoriai. Straipsnyje analizuojamos atskiros vartotojų grupės, šių grupių atstovų poreikiai studijuojant nuotoliniu būdu ir tų
poreikių tenkinimo būdai.
The Analysis of Distance Education Users Needs
Leonidas Sakalauskas, Saulius Preidys
Summary
Different users are participating in distance learning process: teachers (tutors), distance course creators, auditors, VLE administrators. The quality of such studies depends on all of these groups: module developed qualitatively will be convenient for the learner and helpful for the tutor. All the study process depends on the administrator’s activities: if server is working with breaks, studies can become unpredictable and not attractive. In this article the needs of different user groups are analysed and conditions are created for the programming agent development which can improve distance education process.
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Nuotolinio mokymosi stilių personalizavimas
Get PDFMokymosi stiliai yra skirtingi. Kai kurie teikia pirmenybę klausymui ir kalbėjimui, kiti teksto analizei arba mokosi pasitelkę vaizdines priemones. Tačiau daugumos studentų mokymosi stilius yra mišrus. Ypač tai aktualu žinoti kuratoriams ir kursų autoriams, dirbantiems su studentais, studijuojančiais nuotoliniu būdu: reikiamai parengta mokymosi medžiaga, suasmenintos užduotys ir asmeniški komentarai padės studentui greičiau pasiekti iškeltus kurso tikslus ir uždavinius. Šiame straipsnyje
autoriai, remdamiesi Honey ir Mumfordo (1992) sukurta tipologija, nagrinėja mokymosi stilių nustatymą ir vizualizavimą, analizuodami studentų veiklą virtualaus mokymosi aplinkose ir sukauptiems duomenims taikydami duomenų gavybos metodus.
Personalization of Learning Styles in Distance Education
Saulius Preidys, Leonidas Sakalauskas
Summary
Different learners have different styles of learning. Some of them give the priority to listening and speaking, others to text analysis or visual tools. Nevertheless, the learning style of many learners is mixed. Tutors and course creators working with distance learners should be aware of this fact. Appropriate learning materials, personalised assignments and personal comments would help the learner in achieving the aims and objectives of the course. Referring to Honey and Mumford (1992), the authors of the article analyse the determination and visualisation of learning styles, by tracking learners’ activities in virtual learning environments and using data mining methods.
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Kovariantiškumas ir kodiferencija sudarant optimalų vertybinių popierių portfelį
Get PDFFormuojant vertybinių popierių portfelį svarbu nustatyti ryšius tarp atskirų akcijų grąžų. Tačiau laikantis stabilumo prielaidos (modeliuojant akcijų grąžų sekas stabiliaisiais dėsniais) klasikiniai ryšio matai (kovariacija, koreliacija) negali būti taikomi. Todėl apibendrintasis Markovitzo uždavinys yra sprendžiamas su apibendrintais ryšio matais (kovariantiškumas, kodiferencija). Parodyta, kad kodiferencijos tarp atskirų finansinių instrumentų koeficientas gerokai supaprastina portfelio formavimą.
Buvo sudaryti Baltijos šalių dešimties vertybinių popierių optimalūs portfeliai.
On covariation and Codifference in optimal portfolio construction
Igoris Belovas, Audrius Kabašinskas, Leonidas Sakalauskas
Summary
Constructing an optimal portfolio it is essential to determine possible relationships between different stock returns. However, under the assumption of stability (stock returns are modelled with stable laws) accustomed relationship measures covariance, correlation) can not be applied. Thus generalized Markowitz problem is solved with generalized relationship measures (covariation, codifference). Portfolio construction strategies with and without codifference coefficients matrix are given. We show that
the codifference application strongly simplifies the construction of the optimal portfolio. Optimal stock portfolios (with 10 most realizable Baltic States stocks) with and without codifference coefficients matrix are constructed
Tinklo apkrovos savastingumo tyrimas realiu laiku
Get PDFStraipsnyje analizuojami indikatoriai, taikomi tinklo apkrovos savastingumui tirti: Hursto indeksas, stabilumo indeksas, IR (Increment Ratio) statistika. Kompiuteriniu modeliavimu ištirtas šių indikatorių tinkamumas tinklo apkrovos savastingumui vertinti realiu laiku. Sukurta programinių modulių biblioteka SSE (Self-Similarity Estimator), skirta fiksuoti ir agreguoti tinklo duomenų paketus, vertinanti tinklo apkrovos srautų savastingumą realiu laiku. Naudojant SSE programinių modulių biblioteką, suformuotų laiko eilučių Hursto indeksas ir IR statistika apskaičiuotos naudojant analitines formules, o stabilumo indeksas – robastiniu empirinių kvantilių regresijos metodu. Modulių bibliotekos SSE analizės efektyvumas ištirtas kompiuterinio modeliavimo būdu apskaičiuojant savastingumo indikatorius stabiliųjų procesų realizacijoms.
Pagrindiniai žodžiai: savastingumas (self-similarity), Hursto indeksas, stabilumo indeksas, IR statistika.
The Real-time Mode Research of Network Traffic Fractality
Liudvikas Kaklauskas, Leonidas Sakalauskas
Summary
he article analyses the indicators implemented for investigating the network self-similarity: the Hurst index, stability index, IR (Increment Ratio) statistics. The suitability of these indicators for the on-line estimation of network traffic self-similarity was investigated by applying computer-based modelling. The software SSE (Self-Similarity Estimator) module library was developed; it was designed for the recording and aggregation of network traffic packages as well as for the on-line estimation of network traffic self-similarity. By using the SSE software module library, the Hurst index and the IR statistics of time series were estimated by applying analytic formulas, and the index of stability was estimated applying the robust method of regression of empirical quantiles. The efficiency of the analysis of the SSE module library was investigated by estimating the self-similarity indicators for realisation of the stabile processes while applying the method of computer-based modelling
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Statistinis dažnų posekių paieškos algoritmas
Get PDFŠiuolaikinis gyvenimas susijęs su dideliais informacijos bei duomenų kiekiais. Paieška yra viena iš pagrindinių kompiuterio darbo operacijų. Paieškos tikslas – rasti dideliame duomenų kiekyje tam tikrą elementą ar elementų seką arba patvirtinti, kad jos nėra. Pagrindinis duomenų gavybos tikslas – rasti duomenyse prasmę, t. y. ryšius tarp duomenų, jų pasikartojamumą ir pan. Straipsnyje pasiūlytas naujas statistinis dažnų posekių paieškos algoritmas, eksperimentų rezultatai bei išvados. Statistinio dažnų posekių paieškos algoritmo esmė – greitai nustatyti dažnus posekius. Šis algoritmas netikrina viso rinkmenos turinio keletą kartų. Vykdant algoritmą rinkmena peržiūrima vieną kartą pagal pasirinktą tikimybę p. Šis algoritmas yra netikslus, tačiau jo vykdymo laikas daug trumpesnis nei tiksliųjų algoritmų. Statistinis dažnų posekių paieškos algoritmas gali būti taikomas struktūrų paieškos uždaviniui, kai aktualu nustatyti, koks posekis yra dažniausias, tačiau nėra labai svarbu tikslus dažnų posekių skaičius.
Pagrindiniai žodžiai: posekis, kandidatinė seka, duomenų rinkinys, dažnas elementas, elementų rinkinių generavimas, hash funkcija, pirmos rūšies klaida, antros rūšies klaida, pasikliautinumo intervalas.
Statistical Algorithm for Mining Frequent Sequences
Loreta Savulioniene, Leonidas Sakalauskas
Summary
Modern life involves large amounts of data and information. Search is one of the major operations performed by a computer. Search goal is to find a sequence (element) in large amounts of data or to confirm that it does not exist. Amounts of data in databases have reached terabytes, and therefore data retrieval, analysis, rapid decision-making become increasingly complicated. Large quantities of information cover both important and void information. The main goal of data mining is to find the meaning in data, i.e. a relationship between the data, their reproducibility, etc. This technology applies to business, medicine and other areas where large amounts of information are processed and a relationship among data is detected, i.e. new information is obtained from large amounts of data. The paper proposes a new statistic algorithm for repeated sequence search. The essence of this statistic algorithm is to identify repeated sequences quickly. During the algorithm all contents of the file are not checked several times. During the algorithm, the file is checked once according to the chosen probability p. This algorithm is inaccurate, but its execution time is shorter than of the accurate algorithms
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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