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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

An Evaluation of current IDS

Fernandez, Maria del Mar, Porres, Ignacio January 2008 (has links)
<p>With the possibility of connecting several computers and networks the necessity of protecting the whole data and machines from attackers (hackers) that try to get some confident information to use for their own benefit or just destroy or modify valuable information was born. At this point IDS appears to help users, companies or institutions to detect when they are getting compromised. This thesis will cover two main parts: the first one consists of an intense research study about the world of IDS and its environment. Subsequently, we will conclude this part with some points where IDS still needs to be questioned and show up desirable requirements for “the perfect” intrusion detection system. This “perfect” adjective can of course be discussed variously. The second part of the thesis approaches the implementation of the most used open source IDS: Snort. Some basic attacks on the machine where Snort is installed will be performed in order to make the future user see what kind of protection it ensures and the usability of this. There is a brief discussion about two of the main challenges in IDS will follow: analyzing big amounts of packets and encrypted traffic. Finally there are conclusions for a safe computer environment as well as the suggestion that some skilled programmer should give Snort a more friendly interface for every kind of users and a built in programme package which includes webserver, database and other libraries that are needed to run it properly with all its features.</p>
212

Multichannel functional data decomposition and monitoring

Kababji, Hani 01 June 2005 (has links)
With current advances in sensors and information technology, online measurements of process variables become increasingly accessible for process control and monitoring. Such measurements may take the shape of curves rather than scalar values. The term Multichannel Functional Data (MFD) is used to represent the observations of multiple process variables in the shape of curves. Generally MFD contains rich information about processes. The challenge of process control in MFD is that Statistical Process Control (SPC) is not directly applicable. Furthermore, there is no systematic approach to interpret the complex variation in MFD. In this research, our objective is to develop an approach to systematically analyze the complex variation in MFD for process change detection and process faulty condition discrimination. The main contributions of this thesis are: MFD decomposition, process change detection, and process faulty condition discrimination. We decomposed MFD into global and local components. The approach reveals global and local variations that are due to global signal shifts and local variations. Global variation was extracted using weighted spline smoothing technique, whereas, local variation was obtained by subtracting the global variation from original signals. Weights were obtained using the local moving average of the generalized residuals. The proposed approach helps in process change detection and process faulty condition discrimination based on further MFD analysis using Principal Curve Regression (PCuR) Test. For process change detection, global variation component was used in the PCuR test. In-control global data sets were used as training data to detect process change that is due to global and local variation. On the other hand, for faulty condition discrimination purpose, local variation component was used in the PCuR test. In-control local variation data sets were used as training data in the PCuR test; therefore, process faulty condition that is due to local variations remains in control, whereas, process faulty condition that is due to global shifts appears as random out of control points in the PCuR test. We applied our approach on real life forging data sets. A simulation study was also conducted to verify the approach and results are promising for wide applications.
213

Optimization of Proximity Judgment

Day, Brian 01 January 2011 (has links)
As humans, we have evolved to see in three dimensions. Our ancestors developed two eyes that only look forward, which allows the visual area that can perceive depth to be most of the field of view. A variety of sensors have been developed which can determine depth in the environment. They range from producing individual points of depth to the depth of everything in the environment. These sensors have become cheap and can now reliably produce accurate depth. Research is needed to determine how to present the proximity information to the people using the sensors. Touch, sound, and vision have all been used to provide depth information to the users. This research focuses on vision and compares methods of visually presenting proximity information to a user. The methods examined are stereovision and false color visual proximity mapping. False color mapping proved most effective while, surprisingly, stereovision was not helpful.
214

Statistical Learning and Behrens Fisher Distribution Methods for Heteroscedastic Data in Microarray Analysis

Manandhr-Shrestha, Nabin K. 29 March 2010 (has links)
The aim of the present study is to identify the di®erentially expressed genes be- tween two di®erent conditions and apply it in predicting the class of new samples using the microarray data. Microarray data analysis poses many challenges to the statis- ticians because of its high dimensionality and small sample size, dubbed as "small n large p problem". Microarray data has been extensively studied by many statisticians and geneticists. Generally, it is said to follow a normal distribution with equal vari- ances in two conditions, but it is not true in general. Since the number of replications is very small, the sample estimates of variances are not appropriate for the testing. Therefore, we have to consider the Bayesian approach to approximate the variances in two conditions. Because the number of genes to be tested is usually large and the test is to be repeated thousands of times, there is a multiplicity problem. To remove the defect arising from multiple comparison, we use the False Discovery Rate (FDR) correction. Applying the hypothesis test repeatedly gene by gene for several thousands of genes, there is a great chance of selecting false genes as di®erentially expressed, even though the signi¯cance level is set very small. For the test to be reliable, the probability of selecting true positive should be high. To control the false positive rate, we have applied the FDR correction, in which the p -values for each of the gene is compared with its corresponding threshold. A gene is, then, said to be di®erentially expressed if the p-value is less than the threshold. We have developed a new method of selecting informative genes based on the Bayesian Version of Behrens-Fisher distribution which assumes the unequal variances in two conditions. Since the assumption of equal variances fail in most of the situation and the equal variance is a special case of unequal variance, we have tried to solve the problem of ¯nding di®erentially expressed genes in the unequal variance cases. We have found that the developed method selects the actual expressed genes in the simulated data and compared this method with the recent methods such as Fox and Dimmic’s t-test method, Tusher and Tibshirani’s SAM method among others. The next step of this research is to check whether the genes selected by the pro- posed Behrens -Fisher method is useful for the classi¯cation of samples. Using the genes selected by the proposed method that combines the Behrens Fisher gene se- lection method with some other statistical learning methods, we have found better classi¯cation result. The reason behind it is the capability of selecting the genes based on the knowledge of prior and data. In the case of microarray data due to the small sample size and the large number of variables, the variances obtained by the sample is not reliable in the sense that it is not positive de¯nite and not invertible. So, we have derived the Bayesian version of the Behrens Fisher distribution to remove that insu±ciency. The e±ciency of this established method has been demonstrated by ap- plying them in three real microarray data and calculating the misclassi¯cation error rates on the corresponding test sets. Moreover, we have compared our result with some of the other popular methods, such as Nearest Shrunken Centroid and Support Vector Machines method, found in the literature. We have studied the classi¯cation performance of di®erent classi¯ers before and after taking the correlation between the genes. The classi¯cation performance of the classi¯er has been signi¯cantly improved once the correlation was accounted. The classi¯cation performance of di®erent classi¯ers have been measured by the misclas- si¯cation rates and the confusion matrix. The another problem in the multiple testing of large number of hypothesis is the correlation among the test statistics. we have taken the correlation between the test statistics into account. If there were no correlation, then it will not a®ect the shape of the normalized histogram of the test statistics. As shown by Efron, the degree of the correlation among the test statistics either widens or shrinks the tail of the histogram of the test statistics. Thus the usual rejection region as obtained by the signi¯cance level is not su±cient. The rejection region should be rede¯ned accordingly and depends on the degree of correlation. The e®ect of the correlation in selecting the appropriate rejection region have also been studied.
215

Memory performance in young adults with language and learning disabilities

Voss, Kellie Kathleen 19 November 2013 (has links)
This thesis investigated the memory skills of young adults with and without language and learning disabilities (LLD) using the Deese-Roediger-McDermott word recall paradigm (Roediger & McDermott, 1995). Three types of word lists were presented: semantic lists consisted of words that are related to a non-presented critical item (CI) (e.g., bad) in meaning (good, rotten, harmful, worse); phonological lists included words related to the CI in sound (e.g., had, lad, bat, bag); and hybrid lists included words related to the CI in both meaning and sound (e.g., good, lad, rotten, bat). Individuals with diagnoses of LLD were classified as "true LLD" or "compensated LLD" based on language test scores and a discriminating composite score, while those without LLD were considered the "typical language" (TL) group. Hypotheses were made regarding veridical recall and memory intrusions, including intrusions of the non-presented critical item (CI). For veridical recall, the compensated LLD and TL groups were expected to have higher recall accuracy than the true LLD group. As for CI intrusions, two possible outcomes were considered: the true LLD group may recall more CIs due to inability to discriminate between presented and non-presented words (Kirchner & Klatzky, 1985); or they may recall fewer CIs due to difficulties forming traces of the gist of the word list (Weekes et al., 2005). Data from 30 participants (ages 18 to 25) -- 12 true LLD, 8 compensated LLD, and 10 TL -- were included in this thesis. Results indicated that the true LLD group showed a non-significant tendency to have lower recall accuracy scores than the other two groups, and a higher number of CI intrusions. List-type also affected accuracy and CI intrusions, as semantically-related lists increased recall accuracy and hybrid semantic-phonological lists increased CI intrusions. Possible conclusions from these data are presented along with recommendations for future research. / text
216

Memory intrusions in young adults with and without language learning disability

Blecher, Virginia Grace 17 June 2011 (has links)
This report investigated the various types of memory intrusion errors of adults with language learning disability (LLD) in comparison to age- and gender-matched typically developing (TD) adults using lists that are specifically designed to induce memory intrusions adapted from Roediger and McDermott (1995) and modified by Watson et al. (2001; 2003). The 28 participants between the ages of 18:9 - 24:3 listened to pre-recorded lists of twelve words that converged on a critical lure either semantically, phonologically, or dually with a hybrid list. This report tested the hypotheses that 1) hybrid lists would be more likely to induce memory intrusions of the critical lure than either semantic or phonological lists for each group; 2) adults with LLD would demonstrate more intrusion errors than their TD counterparts; 3) the error profiles of the LLD and TD groups should be largely similar; however, the adults with LLD might show deficits in extracting the semantic gist of word lists in light of such patterns in children with specific language impairment (Sheng & McGregor, 2010a). Results showed that the hybrid lists induced the greatest number of critical lure intrusions producing a super-additive effect. Contrary to our hypothesis, the LLD group did not produce more memory intrusions than the TD group. The fact that the two groups performed similarly on all standardized measures suggests that the participants with LLD may have outgrown their disability. Results also revealed that interference and intrusions increased when there was an increase in phonological similarity among words for both groups. Lastly, our preliminary evidence suggests that adults with LLD are not as efficient as their TD counterparts at extracting the gist of semantically-related words. The inclusion of a greater number of participants may provide stronger support for the hypothesis that lexical-semantic organization is less efficient in young adults with LLD. / text
217

The effect of phonological, semantic, and hybrid associates on accurate recall and false memories of adults who stutter : a preliminary study

Delahoussaye, Amy Leigh 08 July 2011 (has links)
There are data to suggest that the phonological representations of young children who stutter are less specified than their typically fluent peers. The purpose of the present study is to determine if this apparent difference in phonological encoding persists in adults who stutter. Utilizing a false memory paradigm, nine adults who stutter (AWS) were asked to listen to and then recall/produce 12 lists of 12 words each. Each word list was comprised of either semantic, phonological or an equal number of semantic and phonological associates of a single, unpresented, critical ‘lure’ word. Three parameters of recall performance were measured across these three conditions: 1) number of accurately recalled productions, 2) number of lure intrusions and 3) number of other intrusions. AWS produced significantly more accurate recalls in the semantic condition than either the hybrid or phonological conditions, and significantly more lure intrusions in the phonological and hybrid conditions than the semantic condition, but there was no significant difference on measures of other intrusions. These results extend the findings with young children who stutter, and indicate that the phonological representations are less robust than the semantic representations in the lexicon of AWS. / text
218

Investigating a Model of False Memory Construction: Is Seeing Believing?

Bays, Rebecca 07 May 2011 (has links)
In the current literature review I examine false memory research, including variables that affect memory accuracy, instrumentation, and analyses used to assess false memory construction, as well as possible frameworks accounting for the development of false memories. Do errors in memory occur during encoding of an event or during retrieval of a memory? I discuss two models of false memories, both born from the source-monitoring framework, to highlight the important cognitive processes leading to crucial errors in memory recall. In the study that follows I investigate whether repeated imaginings of an implausible autobiographical event will lead to the creation of false memories. Plausibility, in the form of prevalence ratings, and visual imagery are manipulated for six suggested events that could have occurred during childhood. A model proposed by Pezdek and colleagues supports the roles of plausibility and imagination in false memory construction (Pezdek, Finger & Hodge, 1997; Pezdek, Blandon-Gitlin & Gabbay, 2006). However, their model is based on research conducted using a Life Events Inventory, a survey that assesses a belief rather than a memory construct. In the present study, I use the Autobiographical Belief and Memory Questionnaire, a survey instrument that distinctly measures plausibility, belief and memory (Scoboria, Mazzoni, Kirsch & Relyea, 2004). Confirmatory factor analysis is employed for instrument validation, followed by a 2 (plausibility: high or low) x 3 (number of imaginings: 0, 1, 5) x 2 (time: pre or post) within subjects ANOVA to test the Pezdek model of false memory construction. Both belief and memory ratings increase significantly when imagination is employed, regardless of event plausibility. However, memory ratings increase as the number of imaginings increase. Belief ratings only increase with one imagining. Present results provide insight into the role of visual imagery on memory accuracy, and inform researchers of appropriate survey instruments and statistical analyses to detect false memories. False memory research is valuable for informing therapeutic techniques, evaluating the reliability of eyewitness testimony, and advising interrogation procedures used by law enforcement and legal officials.
219

An Application of Armitage Trend Test to Genome-wide Association Studies

Scott, Nigel A 17 July 2009 (has links)
Genome-wide Association (GWA) studies have become a widely used method for analyzing genetic data. It is useful in detecting associations that may exist between particular alleles and diseases of interest. This thesis investigates the dataset provided from problem 1 of the Genetic Analysis Workshop 16 (GAW 16). The dataset consists of GWA data from the North American Rheumatoid Arthritis Consortium (NARAC). The thesis attempts to determine a set of single nucleotide polymorphisms (SNP) that are associated significantly with rheumatoid arthritis. Moreover, this thesis also attempts to address the question of whether the one-sided alternative hypothesis that the minor allele is positively associated with the disease or the two-sided alternative hypothesis that the genotypes at a locus are associated with the disease is appropriate, or put another way, the question of whether examining both alternative hypotheses yield more information.
220

Atsakomybė pateikus neteisingus duomenis apie pajamas, pelną ar turtą mokesčių administratoriui / Liability for submission of false data of income, profit or assets to tax administrator

Venclovaitė, Viktorija 22 January 2009 (has links)
Šiame magistro baigiamajame darbe autorė nagrinėja atsakomybę už neteisingų duomenų apie pajamas, pelną ir turtą pateikimą mokesčių administratoriui. Teisinė atsakomybė nagrinėjama sistemingai analizuojant Lietuvos Respublikos įstatymus, poįstatyminius teisės aktus, bei LRKT, LVAT ir LAT jurisprudenciją. Autorė nagrinėja administracinę, mokestinę ir baudžiamąją atsakomybę už neteisingų duomenų pateikimą mokesčių administratoriui. Analizuojant nagrinėjamos veikos sudėtį, iškeliamos teisinės atsakomybės rūšių atribojimo problemos. Daroma vienareikšmė išvada, kad neteisingų duomenų pateikimas mokesčių administratoriui yra valingas mokesčio mokėtojo veikimas siekiant išvengti arba nuslėpti mokesčius. Teisinės atsakomybės rūšies taikymas glaudžiai siejasi su mokesčių mokėtojo pareiga bendradarbiauti su mokesčių administratoriumi, tai atskleista nagrinėjat administracinę ir mokestinę atsakomybę už neteisingų duomenų pateikimą mokesčių administratoriui. Baudžiamoji atsakomybė mokesčių mokėtojui kyla tik tada, jeigu mokesčių administratoriui buvo pateikiami žinomai neteisingi duomenys apie savo pelną, turtą ar pajamas, taip siekiant išvengti mokesčių. Baigiamajame darbe taip pat atsakoma į klausimus, kaip mokesčių administratorius vertina mokesčio mokėtojo pateiktus duomenis, kaip nustatoma ar mokesčio mokėtojo duomenys yra neteisingi bei kaip tokiu atveju apskaičiuojami mokesčiai. Teisinė analizė paremta teisės normų taikymo praktika LRKT, LVAT ir LAT, taip pateikiant pagrindines... [toliau žr. visą tekstą] / The author of the thesis deals with liability for submission of false data to tax administrator. The thesis is based on system analysis of laws and bye-laws of the Republic of Lithuania as well as case-law of the Constitutional Court of the Republic of Lithuania, the Supreme Administrative Court of Lithuania and the Supreme Court of Lithuania. The author examines administrative, fiscal and criminal liability for submission of false data to tax administrator. The criteria used by tax administrator to determine whether the data submitted by a taxpayer is true are analyzed in the thesis. Also the methods of assessing tax base, when it is found that the data of a taxpayer is false, are comprehensively described. The conclusion is being drawn that submission of false data to tax administrator is a voluntary act of a taxpayer having an intention to avoid or conceal taxes. Application of type of legal liability is closely related to the duty of a taxpayer to cooperate with tax administrator; this is demonstrated by analyzing administrative and fiscal liability for submission of false data to tax administrator. Criminal liability is incurred only if a taxpayer has submitted knowingly false data regarding taxpayer’s profit, assets or income to tax administrator having an intention to avoid taxes. Legal analysis is based on application practice of legal norms by the Constitutional Court of the Republic of Lithuania, the Supreme Administrative Court of Lithuania and the Supreme Court of... [to full text]

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