Vanduo – tai labiausiai organizmui reikalingas elementas. Geriamasis vanduo turi būti ne tik skanus, skaidrus, bet, svarbiausia, ir saugus. Baigiamajame darbe tirta kaip buitiniai vandens filtrai išvalo vandenį. Gauti rezultatai parodė, kad tiek vandentiekio, tiek gręžinio filtruotame vandenyje oksidacijos – redukcijos potencialas yra aukštesnis nei nefiltruotame. Filtrai turi įtakos vandens kietumui – Ca, Mg druskų koncentracija neviršija 1,5 mmol/l, vanduo tampa minkštas arba labai minkštas. Taip pat, kiekvieną kartą filtruojant vandenį, mažėja elektrinis laidis. Filtruoto vandens pH, tiek vandentiekio, tiek gręžinio vandenyje, žemesnis nei nefiltruoto. Tai reiškia, kad vanduo tampa rūgštesnis. Didžiausi vandens kokybės pokyčiai gauti organinių medžiagų kiekių atžvilgiu. Šių medžiagų koncentracija sparčiai didėjo tiek vandentiekio, tiek gręžinio filtruotame vandenyje priklausomai nuo filtro kasetės naudojimo laiko. Tai rodo ir determinacijos koeficiento reikšmės – vandentiekio vandenyje – R2 = 0,9, gręžinio vandenyje - R2 = 0,8. / Water - it's most needed element in the body. Drinking water has to be not only delicious, clear, but most importantly, safe and secure. There was studied domestic water filter cleaning efficiency. The results showed that both tap water and borehole water oxidation - reduction potential of the filtered water is higher than the unfiltered. Filters affect the hardness of water - Ca, Mg salt concentration less than 1.5 mmol / l, the water becomes soft or very soft. The observed in the electrical conductivity decrease each time by filtering the water. In assessing the pH parameter, shows that the filtered water is more acidic than the unfiltered. This means that the water becomes more acidic. The most significant changes observed in filtered water by organic matter content changes. These concentrations increased rapidly, depending on the filter cartridge life both tap water and borehole water. This shows a determination coefficient values - tap water – R2 = 0.9, borehole water – R2 = 0.8.

Šio darbo tikslas – sukurti efektyvius įvykių atpažinimo filtrus duomenims, gautiems pasitelkiant pagreičių matavimo prietaisus mobiliosiose technologijose. Atlikus sukurtų filtrų nuodugnius tyrimus įvertinti, kurie iš filtrų įvykius atpažįsta efektyviausiai. Neuroninių tinklų pagalba išskirti duobę ir greičio ribojimo kalnelį iš bendro įvykių srauto. Sukurtą prototipą realizuoti praktiškai ir išsamiai atvaizduoti gaunamus rezultatus. Taip pat susipažinti su kitų autorių sukurtais atpažinimo modeliais bei sistemomis, palyginti jų sukurtų algoritmų bei šio darbo atpažinimo rezultatus, praktiškai realizuoti išnagrinėtą modelį. Užfiksuotoms eismo įvykių koordinatėms pritaikyti tinkamiausią duomenų grupavimo algoritmą ir išsamiai atvaizduoti gautus rezultatus. / The aim of this work was to analyze the data which was gotten from accelerometer mounted in mobile device during the test drives through the city together with GPS (Global Positioning System) coordinates, to detect and report the surface conditions of roads as well as to find the way, how it could be represented in the map. The research was started by analyzing oscillation data from accelerometer. We had to keep in mind that there can be road bumps, pit holes, speed bumps and other road anomalies, car can accelerate quickly and break sharply or even crash into something, what would cause a sudden stop. In order to recognize events, different detection filters were applied on data. In addition to this, neuron network was used to recognize pit holes and speed bumps from all event flow. The results of event detection algorithms were compared with other scientist’s works. In order to represent results clearly, database was created holding coordinates of the road events and other information like time, etc. The results were represented using an application programming interface made-up by Google, which was really suitable solution in our case. The whole system was programmed using Java servlets, which allowed to gather data from database using SQL (Structured Query Language) queries. While trying to represent accelerometer data, we faced difficulties in representing these road events on the map, as GPS each time returned answer with small variation of coordinates. In this case, we... [to full text]

In this work is analyzed the use of digital filter to improve the quality of a speech signal. For this purpose the influence of noises on the understanding of language is inspected and the digital filter design with optimal pole placement is presented. In the process of experimentation the speech signal was recorded by using Praat program, generated noise is made by means of Matlab function randn (n) or the sum two or one cosines. The notated speech signal is mixed with the generated noise. The algorithm based on Matlab program is created to sum up the meanings of speech signal with the corresponding meanings of the noise amplitudes. In order to improve the quality of speech signal mixed with the generated noise, the low pass, notch and strip filters is used, depending on noise, which has been used for connection of noise and a speech signal. The used programs are written down by program Matlab. In the end of the work are show the texts of the algorithms, the text of the created filters and groups of words.

Most of the common DBMS (ORACLE, Microsoft SQL Server, MySQL, DB2, etc.) use disk storage as run time memory. When data becomes necessary from database, DBMS reads them from disk and loads it to RAM (Random Access Memory). This approach uses small amount of RAM, but DBMS efficiency is relative poor. In this work was created prototype of DBMS. This prototype is read-only DBMS and holds all database data in RAM. The purpose of this work is to compare efficiency of common DBMS against created prototype. For this prototype was developed and optimized bunch of data searching, sorting, grouping, joining algorithms. All of these algorithms are based on the main prototype data model idea: database table stores all data into table tree. Prototype and other DBMS were tested with TPCH test, which consists of very different 22 SQL queries to test DBMS efficiency. The test result produced good results for prototype: prototype was 30-40 times faster against ORACLE on complex joining queries and 100-200 times faster against ORACLE on simple joining and searching queries.

Disertacijoje ištirti trupmeniškai integruotų tiesinių laiko eilučių modelių su nestacionaria ilgąja atmintimi dalinių sumų ribiniai skirstiniai ir tam tikros statistikos, susijusios su dalinių sumų procesais. Philippe, Surgailis, Viano 2006 ir 2008 m. darbuose apibrėžė kintančius laike trupmeniškai integruotus filtrus su baigtine dispersija ir nagrinėjo jų dalinių sumų ribinius skirstinius. Disertacijoje ištirti tokių procesų dalinių sumų ribiniai skirstiniai, kai dispersija begalinė, laikant, kad inovacijos priklauso α–stabilaus dėsnio traukos sričiai (čia 1<α<2). Įrodyta, kad dalinių sumų procesas konverguoja į tam tikrą α–stabilų savastingąjį procesą su nestacionariais pokyčiais. Surgailis, Teyssière, Vaičiulis 2008 m. darbe įvedė pokyčių santykių arba IR (= Increment Ratio) statistiką ir parodė, kad IR statistika gali būti naudojama tikrinti neparametrinėms hipotezėms apie stacionariosios laiko eilutės ilgąją atmintį bei ilgosios atminties parametrą d. Disertacijoje apibendrinti šių autorių gauti rezultatai, t. y. įrodyta IR statistikos centrinė ribinė teorema ir gauti poslinkio įverčiai, kai stebiniai aprašomi tiesiniu laiko eilutės modeliu su trendu. Praplėsta laiko eilučių klasė, kuriai IR statistika yra pagrįsta, t. y. konverguoja į vidurkį. / In the thesis is studied the limit distribution of partial sums of certain linear time series models with nonstationary long memory and certain statistics which involve partial sums processes. Philippe, Surgailis, Viano (2006, 2008) introduced time-varying fractionally integrated filters and studied the limit distribution of partial sums processes of these filters under finite variance set-up. In the thesis is studied the limit distribution of partial sums processes of infinite variance time-varying fractionally integrated filters. We assume that the innovations belong to the domain of attraction of an α-stable law (1<α<2) and show that the partial sums process converges to some α-stable self-similar process. In the thesis is studied the limit of the Increment Ratio (IR) statistic for Gaussian observations superimposed on a slowly varying deterministic trend. The IR statistic was introduced in Surgailis, Teyssière, Vaičiulis (2008) and its limit distribution was studied under the assumption of stationarity of observations. The IR statistic can be used for testing nonparametric hypotheses about d-integrated (-1/2 < d <3/2) behavior of the time series, which can be confused with deterministic trends and change-points. This statistic is written in terms of partial sums process and its limit is closely related to the limit of partial sums. In particularly, the consistency of the IR statistic uses asymptotic independence of distant partial sums, the fact is established in the... [to full text]

In the thesis is studied the limit distribution of partial sums of certain linear time series models with nonstationary long memory and certain statistics which involve partial sums processes. Philippe, Surgailis, Viano (2006, 2008) introduced time-varying fractionally integrated filters and studied the limit distribution of partial sums processes of these filters under finite variance set-up. In the thesis is studied the limit distribution of partial sums processes of infinite variance time-varying fractionally integrated filters. We assume that the innovations belong to the domain of attraction of an α-stable law (1<α<2) and show that the partial sums process converges to some α-stable self-similar process. In the thesis is studied the limit of the Increment Ratio (IR) statistic for Gaussian observations superimposed on a slowly varying deterministic trend. The IR statistic was introduced in Surgailis, Teyssière, Vaičiulis (2008) and its limit distribution was studied under the assumption of stationarity of observations. The IR statistic can be used for testing nonparametric hypotheses about d-integrated (-1/2 < d <3/2) behavior of the time series, which can be confused with deterministic trends and change-points. This statistic is written in terms of partial sums process and its limit is closely related to the limit of partial sums. In particularly, the consistency of the IR statistic uses asymptotic independence of distant partial sums, the fact is established in the... [to full text] / Disertacijoje ištirti trupmeniškai integruotų tiesinių laiko eilučių modelių su nestacionaria ilgąja atmintimi dalinių sumų ribiniai skirstiniai ir tam tikros statistikos, susijusios su dalinių sumų procesais. Philippe, Surgailis, Viano 2006 ir 2008 m. darbuose apibrėžė kintančius laike trupmeniškai integruotus filtrus su baigtine dispersija ir nagrinėjo jų dalinių sumų ribinius skirstinius. Disertacijoje ištirti tokių procesų dalinių sumų ribiniai skirstiniai, kai dispersija begalinė, laikant, kad inovacijos priklauso α–stabilaus dėsnio traukos sričiai (čia 1<α<2). Įrodyta, kad dalinių sumų procesas konverguoja į tam tikrą α–stabilų savastingąjį procesą su nestacionariais pokyčiais. Surgailis, Teyssière, Vaičiulis 2008 m. darbe įvedė pokyčių santykių arba IR (= Increment Ratio) statistiką ir parodė, kad IR statistika gali būti naudojama tikrinti neparametrinėms hipotezėms apie stacionariosios laiko eilutės ilgąją atmintį bei ilgosios atminties parametrą d. Disertacijoje apibendrinti šių autorių gauti rezultatai, t. y. įrodyta IR statistikos centrinė ribinė teorema ir gauti poslinkio įverčiai, kai stebiniai aprašomi tiesiniu laiko eilutės modeliu su trendu. Praplėsta laiko eilučių klasė, kuriai IR statistika yra pagrįsta, t. y. konverguoja į vidurkį.