This paper describes various network monitoring technologies and anomaly detection methods. NetFlow were chosen for anomaly detection system being developed. Anomalies are detected using a deviation value. After evaluating quality of developed system, new enhancements were suggested and implemented. Flow data distribution was suggested, to achieve more precise NetFlow data representation, enabling a more precise network monitoring information usage for anomaly detection. Arithmetic average calculations were replaced with more flexible Exponential Weighted Moving Average algorithm. Deviation weight was introduced to reduce false alarms. Results from experiment with real life data showed that proposed changes increased precision of NetFlow based anomaly detection system.

Since the introduction of CUSUM statistic by E.S. Page (1951), detection of change or a structural break in time series has gained significant interest as its applications span across various disciplines including economics, industrial applications, and environmental data sets. However, many of the early suggested statistics, such as CUSUM or MOSUM, lose their effectiveness when applied to time series data. Either the size or power of the test statistic gets distorted, especially for higher order autoregressive moving average processes. We use the test statistic from Gombay and Serban (2009) for detecting change in the mean of an autoregressive process and show how the application of sieve bootstrap to the time series data can improve the performance of our test to detect change. The effectiveness of the proposed method is illustrated by applying it to economic data sets.

ABSTRACT THE EFFECT OF PRE-TRANSFER GRADE POINT AVERAGE ON POST-TRANSFER GRADE POINT AVERAGE AS AN INDICATOR OF PERSISTENCE FROM TWO-YEAR COLLEGES TO STATE COLLEGES AND UNIVERSITIES WITHIN THE UNIVERSITY SYSTEM OF GEORGIA by Marci M. Middleton Community colleges provide an important access point for students who want to continue their educational studies and obtain a baccalaureate or advanced degree. Students have the opportunity to complete core curricula or the general education component of their education at a two-year college and then transfer to a four-year college or university in many higher education systems around the country including the University System of Georgia. Using linear regression initially and later multiple regression, this quantitative research study tested grade point average to project student academic performance at a state or research university upon transfer to such institutions. Data obtained for state systems institutions from fall 2001 through fall 2005 was used for the administration of this study. Research questions concerning the relationship between grade point averages before and after transfer were examined at various matriculation points with specific attention paid to pre-transfer grade point average and post-transfer grade assessment at three points across a student’s academic career. In addition, the strength of the relationship was tested for the aggregate student cohort of matriculants from fall 2001 through fall 2005 as well as sub-groups within the cohort.

In this thesis, we study two methods for inference of parameters in the accelerated failure time model with right censoring data. One is the Wald-type method, which involves parameter estimation. The other one is empirical likelihood method, which is based on the asymptotic distribution of likelihood ratio. We employ a monotone censored data version of Kendall estimating equation, and construct confidence intervals from both methods. In the simulation studies, we compare the empirical likelihood (EL) and the Wald-type procedure in terms of coverage accuracy and average length of confidence intervals. It is concluded that the empirical likelihood method has a better performance. We also compare the EL for Kendall’s rank regression estimator with the EL for other well known estimators and find advantages of the EL for Kendall estimator for small size sample. Finally, a real clinical trial data is used for the purpose of illustration.

Darbo objektas – kariūnų blauzdą tiesiančių ir lenkiančių raumenų funkcinių ypatybių nustatymas ir palyginimas metų eigoje. Tikslas – nustatyti, kaip pasikeičia kariūnų blauzdos raumenų funkcinės ypatybės per 6 mėnesių trukmės fizinio rengimo ciklą. Uždaviniai: 1. Nustatyti blauzdą tiesiančių ir lenkiančių raumenų susitraukimo vidutinį galingumą, maksimalią jėgą, susitraukimo kampą, nuovargį ir atsigavimo kaitą. 2. Palyginti blauzdos raumenų nuovargio ir atsigavimo skirtumą, tarp pirmojo ir antrojo testavimo, esant dinaminiam raumens susitraukimui. Hipotezė - manome, kad atliekant antrąjį testavimą kariūnai po 6 mėn. studijų turi būti fiziškai pajėgesni, labiau turi pasireikšti blauzdą tiesiančių ir lenkiančių raumenų nuovargis ir atsigavimas. Išvados: 1. Abiejų testavimų metu blauzdą tiesiančių ir lenkiančių raumenų susitraukimo vidutinė galia krūvio metu sumažėjo, o praėjus 5 min. po krūvio atsigavo. 2. Blauzdą tiesiančių raumenų maksimali jėga bei atliktas darbas I-ojo testavimo metu yra didesnis negu blauzdą lenkiančių raumenų, tačiau II-ojo testavimo metu pastebimas didesnis nuovargis abiejų raumenų. 3. Blauzdą tiesiančių raumenų maksimalios jėgos kampas abiejų testavimų metu yra vienodas, tačiau blauzdą lenkiančių raumenų II-ojo testavimo metu yra didesnis. 4. Pastebimas ryškus blauzdos raumenų atsigavimas abiejų testavimų metu. / Object of this work – to determine function features of cadets’ shank straighten and bend muscle and to make comparison in the course of year. Aim – to find out how function features of cadets’ shank muscle are changing during 6 months physical training period. Tasks: 1. To establish contraction average power, maximum power, peak torque, tiredness and recuperation alternation of shank straighten and bend muscle. 2. To compare the difference between 1st and 2nd test of shank muscle tiredness and recuperation when there is dynamic contraction of the muscle Hypothesis – it is thought that during 2nd test after 6 months cadets should have more physical power, there should be displayed more intense tiredness and recuperation of shank straighten and bend muscle. Conclusions: 1. During 1st and 2nd test muscle contraction average power in the course of strain has decreased and after 5 min. it has recuperated. 2. Maximum power of shank straighten muscle and work done during the 1st test is bigger than of bend muscle, but during 2nd test there is seen larger tiredness of both muscle. 3. Peak torque of shank straighten muscle during both tests is the same, but peak torque of shank bend muscle is bigger during the 2nd test. 4. There is seen a distinct shank muscle recuperation during both test.

Baigiamajame darbe tiriama grynų ir mišrių maumedynų našumas ir paplitimas Lietuvoje (pagal Lietuvos miškų kadastro elektroninę duomenų bazę, 2010). Darbo objektas – Lietuvos miškuose augantys maumedžiai bei gryni ir mišrūs maumedynai (pagal Lietuvos miškų kadastro elektroninę duomenų bazę, 2010). Darbo tikslas – ištirti svetimkraštės medžių rūšies maumedžio bendrijų našumą, paplitimą, taksacinius ypatumus ir juos palyginti su kitų Lietuvos spygliuočių medžių rūšių (paprastosios pušies ir paprastosios eglės) medynų parametrais. Darbo metodai – monografinis, dokumentų ir taksacinių normatyvų analizės bei taikomosios statistikos metodai. Darbo rezultatai. Atlikus maumedynų tyrimus nustatyta, kad gryni ir mišrūs maumedynai Lietuvoje užima 748,8 ha plotą. Turime 727 miško sklypų su grynais ir mišriais maumedynais. Bendras miškų, kuriuose auga maumedžiai, plotas lygus 2337,7 ha. Miškininkai neįvardina maumedynų rūšies tikslumu (kaip ir Lietuvos beržynų, kuriuos sudaryti gali karpotojo beržo arba plaukuotojo beržo medžiai). Lietuvoje dominuoja Europinio maumedžio medynai. Visi Lietuvos maumedynai kultūrinės kilmės. Jau 50 metų amžiuje (Ld augavietėje) maumedynai pasiekia 380 m3/ha, o brandžiuose ir perbrendusiuose maumedynuose tūris siekia net 800 – 1300 m3/ha. Maumedžiai Lietuvos miškuose pasiekia rekordinį 40 – 45 m aukštį, o savo gimtajame areale - net 55 m aukštį. Lietuvos teritorijoje dominuoja jauni maumedžio miškai (Lietuvos maumedynų vidutinis amžius 36 metai). Bendras... [toliau žr. visą tekstą] / In master's thesis were investigated Lithuanian Larch stands and their productivity. Object of the research work – Larch forests in Lithuania. The aim of the work – is to determine Larch prevalence in Lithuanian state and private forests. Analyze the estimation of forest parameters and compare with local coniferous tree species (Scots Pine and Norway Spruce) stands that grow in similar conditions. Methods of the research work - documents analysis, electronics database analysis The results of the work. Analysis showed that in Lithuania Larch stands occupies 748,8 ha. Best performance was in Ld forest site at age of 50 Larch stand reaches average 380 m3/ha stand volume. Old Larch Stands reach 1300 m3/ha.

Dailės terapijos mokslinės literatūros analizė parodė, jog sutrikusį intelektą turintys vaikai piešia nekreipdami dėmesio į realų objekto vaizdą, nepastebi esminių detalių, nesuvokia objektų tarpusavio ryšių. Tokių vaikų piešiniams būdingi šablonai, apimantys tiek besikartojančią temą, tiek pasikartojančius tuos pačius objektus. Piešinių stereotipiškumas atspindi vaikų reakciją į supantį pasaulį, kur dėmesys fiksuojamas ties aktualiu, keliančiu rūpestį išgyvenimu. Dažniausiai piešiami objektai – namas, medis, žmogus. / The analysis of the art therapy’s scientific sources has revealed that the children having mental disorder draw without focusing on a real image of the object, they don’t pay attention to essential details, don’t realize the existence of the relationship between the objects. The drawings of these kids have got typical patterns with a recurring theme and repeated objects in their pictures. The stereotypical drawings reflect the kids’ reaction to the surrounding. Their attention concentrates on the urgent emotionally stressful experience. The most common objects in such pictures are houses, trees and people.

An explosive growth in demand for broadband mobile wireless services is currently being fuelled by cellular telephone users who, encouraged by service providers, are no longer content with voice transmission only but are demanding real-time video services, including multi-user, interactive games and 'movie' programmes. As these applications develop, expectations mount in other mobile user markets, especially the public safety arena, for comparable user features but with greater emphasis on reliability and robustness of the equipment and supporting network in adverse propagation conditions, remote locations and emergencies. These applications all have in common the requirements for efficient use of wireless bandwidth and of battery power, as well as seamless operation when moving, sometimes at high vehicle speeds, from one type of environment to another in a multi-user scenario. Orthogonal frequency-division multiplexed (OFDM) signals have been found to compare favourably with other modulation systems in these applications, the multi-carrier format being more tolerant of delay spread. It has been used in both code-division (MC-CDMA) and frequency-division (OFDMA) multi-user schemes, the latter having the advantage of maintaining orthogonality among users in fading-signal environments, with consequent simplification of signal processing. The major drawback of OFDM has been the high peak-to-average power ratio (PAPR) that is characteristic of signals with multiple sub-carriers. A result of this is that the transmitter requires a linear power amplifier (PA) that generally has to be 'backed off' to accommodate the high PAPR. Additional back-off is required to achieve linearity, as well as sometimes-complex linearisation circuitry. The power usage and cost of such a transmitter is more acceptable in a base station, tending to limit the application of OFDM to downlinks. The potential application to hand-portable terminals has severe constraints of size, cost and battery life, exacerbated by the use of video-capable LCD displays, increasing motivation for the use of MIMO (multi-antenna) technology and the development of mobile ad-hoc networks, the latter being particularly applicable in the public safety arena. Previous efforts to ameliorate the PAPR problem have been principally directed at two areas, the reduction of signal PAPR, by block coding, clipping or other techniques, and methods of achieving PA linearisation with improved power efficiency. The first object of the present research was to establish, as far as practicable, the current state of the art in these areas, to set a performance baseline. The next step was to develop an improved transmitter modulation scheme that would not only be able to take advantage of any existing peak reduction methods but would transmit a signal that would be compatible with existing OFDM receivers. A novel modulation technique is now presented, termed Quadrature Phase-Time Modulation (QPTM), that has been found to meet the requirements for linearity, simplicity and low cost, whilst being able to take advantage of constant-envelope PA technology, with its attendant power efficiency. After final amplification, the signal is restored by a passive narrow-band filter to standard OFDM form, having both phase and amplitude modulation. The QPTM system of modulation relies on a dual baseband pulse-width modulation process, performed at a substantially-higher rate than the upper baseband frequency, followed by direct quadrature modulation of a carrier signal. The work undertaken has been in the nature of a feasibility study, commencing with the theoretical basis of the technique, from which a behavioural system model was designed and simulated. After the system was simulated successfully, in several forms, a model was designed for realisation with available high-frequency integrated circuits. From this design, prototypes were constructed and tested. The prototype circuit boards also included an experimental UHF Class-D PA circuit, excluding the output filter, to facilitate ongoing development of the PA and filter subsystem as a separate project. This type of PA was seen as a potential complement to the QPTM modulator, although the technology was at an early stage of development. The prototype PA has a novel push-pull arrangement of GaAs FETs that employs a broadside-coupled tapered-stripline balun instead of the usual transformer. Preliminary measurements were made on the PA using both a spectrum analyser and a newly-available 8GHz-bandwidth digital oscilloscope to confirm basic operating characteristics. The performance of the QPTM technique at frequencies needed for broadband operation is dependent on its practical implementation, which has therefore been a major focus. The inherent difficulties in realising a highly-linear 40MHz triangle-wave reference generator, with a precise ultra-high-speed comparator and modulator system, have been overcome with the chosen design techniques and attention to several critical aspects. The result has been the successful demonstration of QPTM as an efficient PA modulation technique that is equally applicable to either narrow-band, high-capacity UHF or broadband OFDM microwave systems.

An average-value model of a rotating rectifier circuit in a brushless excitation system is set forth, where a detailed simulation is required to extract the essential averaged-model parameters using numerical averaging. In the proposed approach, a synchronous machine model with saturation and cross saturation and an arbitrary rotor network representation that uses a voltage-behind-reactance representation for the field winding of the main machine is proposed. This allows the field winding to be represented as branches in a circuit solver, permitting straightforward simulation with connected circuitry. Also a brushless exciter model is introduced to be compatible with the averaged-model, where the exciter armature windings are represented using a voltage-behind-reactance formulation. The resulting average-value model is verified in time domain against detailed simulation, and its validity is demonstrated in all rectifier modes of operation.

Even a modest positive autocorrelation results in a considerable increase in the number of false alarms that are produced when applying a CUSUM chart. Knowledge of the process to be controlled allows for suitable adaptation of the CUSUM procedure. If one has to suspect the normality assumption, nonparametric control procedures such as the rank-based CUSUM chart are a practical alternative. The paper reports the results of a simulation study on the robustness (in terms of sensitivity of the ARL) of the rank-based CUSUM chart against serial correlation of the control variable. The results indicate that the rank-based CUSUM chart is less affected by correlation than the observation-based chart: The rank-based CUSUM chart shows a smaller increase in the number of false alarms and a higher decrease in the ARL in the out-of-control case than the the observation-based chart. (author's abstract) / Series: Forschungsberichte / Institut für Statistik