The distribution and access to information by a much larger number of people on the Internet has grown in a exponential, way has been hard the which control of the originality of the information and facilitating the work of plagiarists users who make use of such information inappropriately. It is in this context that stands the importance of evalute the texts produced in the post-graduate and graduate courses in the classroom and distance modalities, that this paper proposes a new method to detect signs of plagiarism in academic work, which performs to searche similar fragments with web documents. The method developed analyzes the mosaic plagiarism, where the author shares copies of a work by changing only a few words without giving credit to the original work, and the bilingual plagiarism, where the contents of a document in English is translated for Portuguese without reference the original work. In addition, the method was implemented in an integrated tool and to the sending task module of the Moodle platform for access by desktop and by the mobile device aiming to empower the teachers the benefits of its utilization in the posting of work in a AVA, and implemented as a desktop computer system to allow users the access also outside theAVA Moodle. The results showed that the developed method reached satisfactory results in relation to other techniques found in literature, getting over a collection of 14 documents indexs of similarities ranging from 30.07% to 40% and with a precision in the returned results between 71.42 % and 96.15%. The experimental results of a translated document from English to Portuguese had a 100% accuracy in the returned results. / A distribuição e o acesso a informações por um número muito maior de pessoas na internet tem crescido de forma exponencial, o que vem dificultando o controle da originalidade de tais informações e facilitando o trabalho dos usuários plagiadores que fazem uso de tais informações de forma inadequada. Neste contexto que se destaca a importância de avaliar os textos produzidos nos cursos de pós-graduação e graduação, nas modalidades à distância e presenciais, que esta dissertação propõe um novo método para detecção de índicios de plágio em trabalhos acadêmicos, o qual realiza buscas por fragmentos similares com documentos da web. O método desenvolvido analisa o plágio mosaico, onde o autor copia partes de uma obra trocando somente algumas palavras sem dar crédito ao autor da obra original; e o plágio bilíngue, onde o conteúdo de um documento no idioma inglês é traduzido para o idioma português sem fazer referência à obra original. Além disso, o método foi implementado em uma ferramenta e integrada ao módulo de envio de tarefas da plataforma Moodle para acesso via desktop e pelo dispositivo móvel, visando potencializar aos professores os benefícios de sua utilização, já na postagem dos trabalhos no AVA; e implementada como um sistema computacional desktop para permitir aos usuários seu acesso também fora do AVA Moodle. Os resultados obtidos mostram que o método desenvolvido alcançou resultados satisfatórios em relação a outras técnicas encontrados na literatura, obtendo sobre uma coleção de 14 documentos índices de similaridades variando de 30,07% a 40% e com uma precisão nos resultados retornados entre 71,42% e 96,15%. Os resultados do experimento de um documento traduzido do inglês para o português teve uma precisão de 100% nos resultados retornados.

The research overview is expected to contribute with knowledge of MLE, Mediated Learning Enrichment and FIE, Feuerstein's Instrumental Enrichment program/Feuerstein's cognitive intervention program and its effects, primarily among students with learning disabilities but also among educators.   A research overview focusing on scientific articles, published in 2010-2020. The purpose of the study is to analyze results in current research that evaluates the effects of MLE and FIE among students with learning disabilities and among educators, as reported in scientific articles and to relate the results analysis to a Swedish school context. The research questions are based on scientific articles in which a program for pedagogical work and attitudes (MLE and FIE) has been analyzed: 1.              Which effects of the program are described in the current studies? 2.              Which opportunities and obstacles can be found in working with the program? 3.              Which significance can the program have for the design of the learning environment and in relation to the role of the special education teacher? In which context?  I have chosen three perspectives to analyze the scientific articles: a sociocultural, a special educational and an organizational theory perspective. The program benefits the development of cognitive abilities for everyone and should be applied at a group level.  The impact of the home on the cognitive capacity of the students is crucial and a rich or less favorable home environment makes a difference. Parental training in MLE are advocated and differences between the conditions for children at school start could disappear completely through such intervention.  When children do not bring developed cognitive abilities to school, the school needs to be prepared to meet and mediate for positive learning. If teachers are educated in mediated learning, they can lay the foundation for their students. It is recommended that the program becomes part of the curriculum and teacher training. In order to see the effects of the program there is a need of; FIE teacher training, effective implementation of the program, sufficient time that students are exposed to the FIE program and coverage of instruments.  Effective digital MLE tools are needed to enhance self-regulating learning in our digital age. Obstacles are organizational, in terms of the cost and time of training; the fact that the education takes place in English and that it requires a licensed FIE instructor.  The socratic questions stimulate motivation and sense of meaning for everyone. Students develop more effective strategies, based on “Stop and think!”, instead of using the exclusion method.  There is a need for close cooperation between educators and special educators to include everyone at a group level. / Forskningsöversikten förväntas bidra med kunskap om MLE, Mediated Learning Enrichment och FIE, Feuersteins Instrumental Enrichment program/ Feuersteins kognitiva interventionsprogram och dess effekter, främst för elever i inlärningssvårigheter men även för pedagoger.  En forskningsöversikt med fokus på vetenskapliga artiklar, publicerade år 2010-2020. Syftet med studien är att analysera resultat i aktuell forskning som utvärderar effekterna av MLE och FIE för elever i inlärningssvårigheter och för pedagoger. Resultatanalysen relateras till en svensk skolkontext.  Forskningsfrågorna bygger på vetenskapliga artiklar där ett program för pedagogiskt arbete och attityder (MLE och FIE) har analyserats: -Vilka effekter av programmet beskrivs i de aktuella studierna?  -Vilka möjligheter och hinder finns i arbetet med programmet?  -Vilken betydelse kan programmet ha för utformningen av lärmiljön och i förhållande till specialpedagogens roll? I vilket sammanhang? Jag har valt tre perspektiv för att analysera de vetenskapliga artiklarna; ett sociokulturellt, ett specialpedagogiskt och ett organisationsteoretiskt perspektiv. Programmet gynnar utvecklingen av kognitiva förmågor för alla och bör tillämpas på gruppnivå. Hemmets inverkan på elevers kognitiva kapacitet är avgörande och en rik eller mindre gynnsam hemmiljö gör skillnad. Föräldrautbildning i MLE förespråkas och skillnader mellan villkor för barn vid skolstart kan försvinna helt. När barn inte tar med sig utvecklade kognitiva förmågor till skolan måste skolan vara beredd att mediera för ett positivt lärande. Om lärare utbildas i medierat lärande kan de lägga grunden hos sina elever. Det rekommenderas att programmet blir en del av läroplanen och lärarutbildning. För att se effekterna av programmet finns det ett behov av; FIE-lärarutbildning, effektiv implementering av programmet, tillräckligt med tid för att eleverna exponeras för FIE-programmet och täckning av instrument. Effektiva digitala MLE-verktyg behövs för att förbättra självreglerat lärande i vår digitala tidsålder. Hinder är organisatoriska när det gäller kostnader och tid för utbildning, utbildningen sker på engelska och den kräver en licensierad FIE-instruktör. De sokratiska frågorna stimulerar motivation och känslan av mening för alla. Eleverna utvecklar effektivare strategier, baserade på "Stanna upp och tänk efter!", istället för att använda exkluderingsmetoder. Det finns ett behov av ett nära samarbete mellan pedagoger och specialpedagoger för att inkludera alla på gruppnivå.

MHC Klasse II Moleküle präsentieren Peptidantigene für die Überwachung durch CD4+ T Zellen an der Zelloberfläche. Um Sicherzustellen, dass diese Peptidliganden möglichst genau die intrazelluläre Proteinzusammensetzung widerspiegeln, hat sich im Verlauf der Evolution ein komplexer Prozessierungsweg entwickelt, welcher möglichst stabile Peptid/MHC Komplexe an die Zelloberfläche liefert. MHC Moleküle, welche ihren Liganden verloren haben, konvertieren zudem spontan in einen ‚nichtrezeptiven’ Zustand, was als zusätzlicher Sicherheitsmechanismus dient. Diese Studie zeigt jedoch, dass Aminosäureseitenketten kurzer Peptide diesen Sicherheitsmechanismus umgehen können indem sie katalytisch einen reversiblen Ligandenaustausch auslösen. Die katalytische Aktivität von Dipeptiden, wie z.B. Tyr-Arg (YR), war dabei stereospezifisch und konnte durch zusätzliche Modifikationen verstärkt werden, welche das konservierte H-Brückennetzwerk der so genannten P1-Tasche des MHC Moleküls adressierten. Die Dipeptide verstärkten dabei sowohl die Antigenbeladung als auch den Ligandenaustausch, wobei deren relative Aktivität genau mit den bekanten Ankerpräferenzen der P1 Tasche korrelierte. Letzteres weist somit auf eine direkte Interaktion der katalytischen Seitenkette des Dipeptides mit dieser Tasche hin. Der Verstärkungseffekt war auch in CD4+ T Zellassays zu beobachten, bei denen der alleleselektive Einfluss der Dipeptide direkt in eine deutliche Erhöhung der Sensitivität der antigenspezifischen T Zellantwort führte. Durch weitere molekulardynamische Berechnungen konnte die Hypothese unterstützt werden, dass die Besetzung der P1 Tasche durch Aminosäureseitenketten einen Kollaps der leeren Bindungstasche zum ‚nichtrezeptiven’ Zustand verhindert. Während der Antigenpräsentation könnte P1 somit unmittelbar als ‚Sensor’ für die Beladung mit Peptiden dienen. Diese Annahme konnte experimentell durch spektroskopische Untersuchungen unter Verwendung des ANS-Farbstoffes (8-Anilino-1-Naphtalensulfonsäure) sowie durch Messung der intrinsischen Tryptophanfluoreszenz bestätigt werden. Darüber hinaus konnten konformationsspezifische Antikörper, welche bislang lediglich mit unbeladenen MHC Molekülen in Verbindung gebracht wurden, hier als spezifische Sonden für den nichtrezeptiven Zustand definiert werden. Als mögliche Risikofaktoren könnten katalytische kurze Peptide eine Rolle bei der Auslösung von Autoimmunerkrankungen spielen. In dieser Studie konnte gezeigt werden, dass sie die Beladung von Glutenantigenen auf das Zöliakie-assozierte HLA-DQ2 Molekül verstärken können. Zumindest in vitro konnte ihre Anwesenheit deshalb auch die antigenspezifische Antwort von CD4+ T Zellen verstärken, welche zuvor von Zöliakiepatienten isoliert worden waren. Auf der einen Seite könnten diese Peptide als ‚MHC-loading enhancer’ (MLE) deshalb als mögliche Risikofaktoren die Ausbildung entzündlicher (Auto-) Immunerkrankungen beschleunigen. Auf der anderen Seite könnten sie jedoch auch als ‚drug-like’ Vakzinadditiv zur Verbesserung von Immuntherapien führen. / MHC class II molecules present antigenic peptides on the cell surface for the surveillance by CD4+ T cells. To ensure that these ligands accurately reflect the content of the intracellular MHC loading compartment, a complex processing pathway has evolved that delivers only stable peptide/MHC complexes to the surface. As additional safeguard mechanism, MHC molecules quickly acquire a ‘non-receptive’ state once they have lost their ligand. This study shows that amino acid side chains of short peptides can bypass these safety mechanisms by triggering the reversible ligand-exchange. The catalytic activity of dipeptides such as Tyr-Arg (YR) is stereo-specific and could be enhanced by modifications addressing the conserved H-bond network near the P1 pocket of the MHC molecule. It enhanced both antigen-loading and ligand-release and strictly correlated with reported anchor preferences of P1, the specific target site for the catalytic side chain of the dipeptide. The effect was evident also in CD4+ T cell assays, where the allele-selective influence of the dipeptides translated into increased sensitivities of the antigen-specific immune response. The hypothesis that occupation of P1 prevents the ‘closure’ of the ‘empty’ peptide binding site into the ‘non-receptive’ state was further supported by molecular dynamic calculations. During antigen processing and presentation P1 may therefore function as important ‘sensor’ for peptide-load. Spectroscopic studies using ANS dye (8-aninilino-1-napthalenesulfonic acid) and intrinsic tryptophan fluorescence data, confirm the postulate by providing direct evidence for the conformational transitions. Moreover conformation specific antibodies previously described to be specific for ‘empty’ MHC could be shown to be a ‘probe’ for ‘receptive conformation’. As potent risk factors short peptides may be involved in the induction of autoimmune diseases. It could be shown here that they could enhance the loading of gluten derived antigen on celiac disease linked-HLA-DQ2 allele. At least in vitro the effect could enhance gluten specific CD4+ T cell response on T cell clones obtained from celiac disease patients. Thus, on one hand short peptides might work as ‘MHC loading enhancer’ (MLE) in the precipitation of inflammatory-‘autoimmune’ disorder, on the other hand they might be used as drug like vaccine ‘additive’ in various therapeutic settings.

Jump diffusion models are being used more and more often in financial applications. Consisting of a Brownian motion (with drift) and a jump component, such models have a number of parameters that have to be set at some level. Maximum Likelihood Estimation (MLE) turns out to be suitable for this task, however it is computationally demanding. For a complicated likelihood function it is seldom possible to find derivatives. The global maximum of a likelihood function defined for a jump diffusion model can however, be obtained by numerical methods. I chose to use the Bound Optimization BY Quadratic Approximation (BOBYQA) method which happened to be effective in this case. However, results of Maximum Likelihood Estimation (MLE) proved to be hard to interpret.

Η παρούσα μεταπτυχιακή διατριβή εντάσσεται ερευνητικά στην περιοχή της Στατιστικής Θεωρίας Αποφάσεων και ειδικότερα στην εκτίμηση των παραμέτρων στο μοντέλο της διπαραμετρικής εκθετικής κατανομής με παράμετρο θέσης μ και παράμετρο κλίμακος σ. Θεωρούμε ένα δείγμα n τυχαίων μεταβλητών, καθεμία από τις οποίες ακολουθεί την διπαραμετρική εκθετική κατανομή. Λογοκρίνουμε κάποιες αρχικές παρατηρήσεις και έστω ότι τερματίζουμε το πείραμά μας πριν αποτύχουν όλες οι συνιστώσες. Τότε προκύπτει ένα διπλά διακεκομμένο δείγμα διατεταγμένων παρατηρήσεων. Η εκτίμηση των παραμέτρων της διπαραμετρικής εκθετικής κατανομής, γίνεται από το συγκεκριμένο δείγμα. Πρώτα μελετάμε κάποιες βασικές έννοιες της Στατιστικής και της Εκτιμητικής και βρίσκουμε εκτιμητές για τις παραμέτρους. Πιο συγκεκριμένα, βρίσκουμε αμερόληπτο εκτιμητή ελάχιστης διασποράς, εκτιμητή μέγιστης πιθανοφάνειας, εκτιμητή με την μέθοδο των ροπών και τον βέλτιστο αναλλοίωτο εκτιμητή σε συγκεκριμένη κλάση, αντίστοιχα και για τις δύο παραμέτρους. Σαν βελτίωση των προηγούμενων εκτιμητών, ακολουθούν οι εκτιμητές τύπου Stein και, ολοκληρώνοντας, ασχολούμαστε με πρόβλεψη κατά Bayes για μια μελλοντική παρατήρηση / The present master thesis deals with the estimation of the location parameter μ and the scale parameter σ of the two-parameter exponential distribution. A sample n of random variables from the two-parameter exponential distribution is assumed. Part of the initial variables is censored and the experiment is terminated before all the components fail. A doubly censored sample emerges from which the two-parameter exponential distribution's parameters are estimated. First of all, basic Statistics' concepts are studied in order to estimate the parameters. More specifically, the Minimum Variance Unbiased Estimator (MVUE), the Maximum Likelihood Estimator (MLE), the estimator based on the Method of Moments and the best affine equivariant estimator are computed for both the parameters. To improve the previous estimators, the Stein method is used and to conclude the Bayes prediction is used for future observation

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The rapid increasing interest in wireless communication has led to the continuous development of wireless devices and technologies. The modern convergence and interoperability of wireless technologies has further increased the amount of services that can be provided, leading to the substantial demand for access to the radio frequency spectrum in an efficient manner. Cognitive radio (CR) an innovative concept of reusing licensed spectrum in an opportunistic manner promises to overcome the evident spectrum underutilization caused by the inflexible spectrum allocation. Spectrum sensing in an unswerving and proficient manner is essential to CR. Cooperation amongst spectrum sensing devices are vital when CR systems are experiencing deep shadowing and in a fading environment. In this thesis, cooperative spectrum sensing (CSS) schemes have been designed to optimize detection performance in an efficient and implementable manner taking into consideration: diversity performance, detection accuracy, low complexity, and reporting channel bandwidth reduction. The thesis first investigates state of the art spectrums sensing algorithms in CR. Comparative analysis and simulation results highlights the different pros, cons and performance criteria of a practical CSS scheme leading to the problem formulation of the thesis. Motivated by the problem of diversity performance in a CR network, the thesis then focuses on designing a novel relay based CSS architecture for CR. A major cooperative transmission protocol with low complexity and overhead - Amplify and Forward (AF) cooperative protocol and an improved double energy detection scheme in a single relay and multiple cognitive relay networks are designed. Simulation results demonstrated that the developed algorithm is capable of reducing the error of missed detection and improving detection probability of a primary user (PU). To improve spectrum sensing reliability while increasing agility, a CSS scheme based on evidence theory is next considered in this thesis. This focuses on a data fusion combination rule. The combination of conflicting evidences from secondary users (SUs) with the classical Dempster Shafter (DS) theory rule may produce counter-intuitive results when combining SUs sensing data leading to poor CSS performance. In order to overcome and minimise the effect of the counter-intuitive results, and to enhance performance of the CSS system, a novel state of the art evidence based decision fusion scheme is developed. The proposed approach is based on the credibility of evidence and a dissociability degree measure of the SUs sensing data evidence. Simulation results illustrate the proposed scheme improves detection performance and reduces error probability when compared to other related evidence based schemes under robust practcial scenarios. Finally, motivated by the need for a low complexity and minmum bandwidth reporting channels which can be significant in high data rate applications, novel CSS quantization schemes are proposed. Quantization methods are considered for a maximum likelihood estimation (MLE) and an evidence based CSS scheme. For the MLE based CSS, a novel uniform and optimal output entropy quantization scheme is proposed to provide fewer overhead complexities and improved throughput. While for the Evidence based CSS scheme, a scheme that quantizes the basic probability Assignment (BPA) data at each SU before being sent to the FC is designed. The proposed scheme takes into consideration the characteristics of the hypothesis distribution under diverse signal-to-noise ratio (SNR) of the PU signal based on the optimal output entropy. Simulation results demonstrate that the proposed quantization CSS scheme improves sensing performance with minimum number of quantized bits when compared to other related approaches.

The amount of carbon dioxide in the Earth’s atmosphere has significantly increased in the last few decades as compared to the last 80,000 years approximately. The increase in carbon dioxide levels are affecting the temperature and therefore need to be understood better. In order to study the effects of global events on the carbon dioxide levels, one need to properly estimate the trends in carbon dioxide in the previous years. In this project, we will perform the task of estimating the trend in carbon dioxide measurements taken in Mauna Loa for the last 46 years, also known as the Keeling Curve, using estimation techniques based on a Taylor and Fourier series model equation. To perform the estimation, we will employ Maximum Likelihood Estimation (MLE) and the Cramér-Rao Lower Bound (CRLB) and review our results by comparing it to other estimation techniques. The estimation of the trend in Keeling Curve is well-posed however, the estimation for the first derivative of the trend is an ill-posed problem. We will further calculate if the estimation error is under a suitable limit and conduct statistical analyses for our estimated results.

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