O objetivo deste trabalho é apresentar um novo método para a remoção do ruído Poisson em imagens de mamografia digital adquiridas com baixa dosagem de radiação. Sabe-se que a mamografia por raios X é o exame mais eficiente para a detecção precoce do câncer de mama, aumentando consideravelmente as chances de cura da doença. No entanto, a radiação absorvida pela paciente durante o exame ainda é um problema a ser tratado. Estudos indicam que a exposição à radiação pode induzir a formação do câncer em algumas mulheres radiografadas. Apesar desse número ser significativamente baixo em relação ao número de mulheres que são salvas pelo exame, existe a necessidade do desenvolvimento de meios que viabilizem a diminuição da dose de radiação empregada. No entanto, uma redução na dose de radiação piora a qualidade da imagem pela diminuição da relação sinal-ruído, prejudicando o diagnóstico médico e a detecção precoce da doença. Nesse sentido, a proposta deste trabalho é apresentar um método para a filtragem do ruído Poisson que é adicionado às das imagens mamográficas quando adquiridas com baixa dosagem de radiação, fazendo com que ela apresente qualidade equivalente àquela adquirida com a dose padrão de radiação. O algoritmo proposto foi desenvolvido baseado em adaptações de algoritmos bem estabelecidos na literatura, como a filtragem no domínio Wavelet, aqui usando o Shrink-thresholding (WTST), e o Block-matching and 3D Filtering (BM3D). Os resultados obtidos com imagens mamográficas adquiridas com phantom e também imagens clínicas, mostraram que o método proposto é capaz de filtrar o ruído adicional incorporado nas imagens sem perda aparente de informação. / The aim of this work is to present a novel method for removing the Poisson noise in digital mammography images acquired with reduced radiation dose. It is known that the X-ray mammography is the most effective exam for early detection of breast cancer, greatly increasing the chances of healing the disease. However, the radiation absorbed by the patient during the exam is still a problem to be treated. Some studies showed that mammography can induce breast cancer in a few women. Although this number is significantly low compared to the number of women who are saved by the exam, it is important to develop methods to enable the reduction of the radiation dose used in the exam. However, dose reduction led to a decrease in image quality by means of the signal to noise ratio, impairing medical diagnosis and the early detection of the disease. In this sense, the purpose of this study is to propose a new method to reduce Poisson noise in mammographic images acquired with low radiation dose, in order to achive the same quality as those acquired with the standard dose. The method is based on well established algorithms in the literature as the filtering in Wavelet domain, here using Shrink-thresholding (WTST) and the Block-matching and 3D Filtering (BM3D). Results using phantom and clinical images showed that the proposed algorithm is capable of filtering the additional noise in images without apparent loss of information.

O procedimento matching-to-sample (MTS) tem sido amplamente utilizado para o estabelecimento de relações condicionais emergentes. Nesse procedimento, respostas de escolha são emitidas em diferentes localizações. Tal característica pode favorecer o estabelecimento de um controle inadvertido pela localização. No procedimento go/no-go com estímulos compostos, respostas são emitidas em uma única localização. Com o objetivo de avaliar se relações condicionais emergentes poderiam ser produzidas em crianças com autismo a partir do procedimento go/no-go com estímulos compostos, sem o estabelecimento de controle inadvertido pela localização, foram realizados dois estudos. No Estudo 1, quatro crianças autistas, que apresentaram controle pela localização no procedimento MTS, foram submetidas ao treino das relações AB e BC com o procedimento go/no-go com estímulos compostos no qual, respostas emitidas na presença dos estímulos compostos A1B1, A2B2, B1C1 e B2C2 eram seguidas de reforço e respostas na presença de compostos A1B2, A2B1, B1C2 e B2C1 não eram. Em seguida, os participantes realizaram testes para verificar a emergência de relações que não foram diretamente treinadas (BA, CB, AC e CA). Os resultados mostraram que apenas um dos quatro participantes atingiu critério de aprendizado no treino das relações condicionais e exibiu desempenhos consistentes com a emergência de relações de simetria, transitividade e equivalência após a reapresentação de sessões de treino e testes. Todos os participantes apresentaram o padrão de responder em todos os compostos apresentados. Como decorrência do Estudo 1, foi realizado um segundo estudo que pretendeu verificar se relações condicionais emergentes podem ser estabelecidas em indivíduos com diagnóstico de autismo a partir de um treino com o procedimento go/no-go com estímulos compostos em que a duração dos estímulos compostos aos quais o participante não deveria responder foi gradualmente aumentada com o objetivo de evitar respostas diante deles. Para tanto, outras três crianças diagnosticadas com autismo foram submetidas às mesmas fases experimentais do Estudo 1 dentre as quais algumas diferiam pela manipulação na duração dos compostos. Os resultados mostraram que apenas um dos participantes atingiu critério para realização dos testes de Simetria, mas não exibiu desempenho consistente com a emergência de tais relações. Os outros dois participantes não atingiram critério de aprendizagem na fase de Pré-treino ou de Treino, devido ao estabelecimento do padrão de responder em todos os compostos. Os resultados indicam ainda que o procedimento de aumento gradual na duração dos estímulos favoreceu o aprendizado das relações condicionais para um dos participantes, mas pode gerar o estabelecimento do controle inadvertido pela duração dos estímulos. Os participantes que realizaram o treino com o procedimento MTS não atingiram critério de aprendizagem e exibiram desempenhos indicativos do estabelecimento de controle inadvertido pela localização. Concluiu-se que o procedimento go/no-go com estímulos compostos, embora tenha permitido o estabelecimento de desempenhos emergentes para um dos participantes, pode gerar um padrão de responder em todos os compostos mesmo com o procedimento de aumento gradual na duração dos compostos diante dos quais o participante não deve responder. / Matching-to-sample procedure is widely used for establishing emergent conditional relations. However, adventitious control by location, rather than the conditional control, can be established with this procedure in individuals with autism. With the go/no-go procedure with compound stimuli, participants responses are emitted in a single location. Aiming to assess whether emergent conditional relations could be established in autistic children with a go/no-go procedure with compound stimuli, without the establishment adventitious control by location, two studies were conducted. Study 1 sought to verify if the go/no-go procedure with compound stimuli would establish emergent conditional relations in children diagnosed with autism who had control by the location in training with Matching-to-sample procedure. Four autistic children, who showed adventitious control by location in a matching-to-sample task, were submitted to AB and BC training with the go/no-go procedure with compound stimuli. Responses emitted in the presence of A1B1, A2B2, B1C1 and B2C2 compounds were followed by reinforcers and responses emitted in the presence of A1B2, A2B1, B1C2 and B2C1 were not. After that, participants were submitted to tests to verify emergence of conditional relations (BA, CB, AC and CA) that were not directly trained. The results showed that only one of the four participants met the learning criterion in training and exhibited emergent performances in tests only after retraining the baseline relations. In most of the training sessions, all participants responded to all compounds stimuli. These results show that refrain from responding is difficult to be established with the go/no-go procedure in children with autism. Study 2 was conducted to verify if refrain from responding would be established in children with autism if the duration of compounds that should not control responding in training was gradually increased. Other three children diagnosed with autism were submitted to the same procedure as conducted in Study 1, except that during pre-training and training duration of some compounds were gradually increased in some sessions. Results showed that only one participant met the learning criteria in training, but did not showed emergent performances in tests. The other two participants responded to all compounds in most of the sessions. The results indicate that the gradual increase of stimuli duration did not established refrain from responding for some participants and produced adventitious control by stimuli duration for most of them. Although one participant showed emergent performances with the go/no-go procedure with compound stimuli, this procedure can produce responses to all compounds stimuli even when some compounds duration is gradually increased.

A leitura é uma habilidade complexa que envolve uma rede de relações entre estímulos e entre estímulos e respostas. Para que um repertório de leitura seja considerado proficiente, o leitor deve apresentar a leitura de novas palavras, não diretamente ensinadas e formadas pela recombinação de unidades aprendidas previamente em outras relações (leitura recombinativa). Um requisito fundamental para o desenvolvimento da leitura recombinativa é, portanto, o estabelecimento de um responder diferencial sob controle das unidades menores, como por exemplo, sílabas, letras ou fonemas, componentes das palavras. O objetivo do presente trabalho foi investigar o efeito do treino direto de fonemas, combinado com um treino de palavras, sobre a emergência da leitura recombinativa de palavras inteiras. Verificou-se também se o momento de inserção do treino de fonemas no procedimento de ensino, se prévio (Condição I) ou sobreposto (Condição II) ao treino de palavras, foi uma variável relevante para a emergência da leitura recombinativa. Os participantes do estudo foram 12 estudantes universitários, com idades entre 18 e 37 anos, e que foram distribuídos igualmente entre três Condições Experimentais: a) Condição I Treino Prévio de Fonemas; b) Condição II Treino Sobreposto de Fonemas; c) Condição IIITreino de palavras. A Condição III foi realizada com o objetivo permitir uma comparação entre o desempenho dos participantes que foram submetidos ao treino de fonemas (Condições I e II) com o dos participantes que foram expostos somente ao treino de palavra (Condição III). Os estímulos utilizados no estudo consistiram de palavras faladas (A) e palavras escritas com um pseudoalfabeto (C), bem como de fonemas e letras do pseudoalfabeto, correspondentes a estes fonemas. Os procedimentos empregados tanto para o treino de fonemas como para o treino de palavras inteiras foram os procedimentos de MTS (relação AC) e de Nomeação Oral (relação CD). Os testes para verificar a emergência da leitura recombinativa foram os mesmos nas três Condições Experimentais e consistiram em testes parciais de leitura oral (Testes CD) e de leitura receptiva (Testes AC), e em um Teste Final de Leitura Oral. Os resultados demonstraram que o treino direto de fonemas (Condições I e II) foi eficaz em estabelecer leitura recombinativa com elevados índices de acertos e pouca variabilidade intra e inter-participantes. O momento de inserção do treino de fonemas no procedimento de ensino foi uma variável relevante e possibilitou a observação de resultados distintos entre os participantes submetidos às Condições I e II. Os resultados sugerem que os participantes submetidos a Condição II (Sobreposto) foram os que apresentaram maior velocidade na recombinação e índices mais elevados de leitura recombinativa, enquanto os participantes submetidos a Condição I (Prévio) foram os que apresentaram menor variabilidade entre si / Reading is a complex skill that involves a network of relationships between stimuli and between stimuli and responses. A repertoire of proficient reading is considered when the reader is able to read new words, not directly taught and composed by the recombination of units previously learned in other relationships (recombinative reading). An essential requirement for the development of recombinative reading is thus establishing a differential responding under the control of smaller units, such as syllables, phonemes or letters, components of the words. The objective of this study was to investigate the effect of direct training of phonemes, combined with a training of words, upon the emergence of recombinative reading of whole words. It was also verified the effect of the moment of insertion of phoneme training in the teaching procedure, prior (Condition I) and overlapping (Condition II) to word training. The participants were 12 college students, aged between 18 and 37 years, which were equally distributed among three Experimental Conditions: a) Condition I Prior Phoneme Training, b) Condition II Overlapping Phoneme Training; c) Condition III Word Training. Condition III was conducted in order to allow a comparison between the performance of participants who were submitted to phoneme training (Condition I and II) and the performance of participants who were exposed only to word training (Condition III). The stimuli used in the study consisted of spoken pseudowords (A) and printed pseudowords (C), as well phonemes and letters form the pseudo-alphabet corresponding to these phonemes. The procedures applied for both phoneme and word training were MTS (AC relation) and Oral Naming (CD relation). Tests to verify the emergence of recombinative reading were the same in all three Experimental Conditions and consisted of partial tests of oral reading (Tests C\'D) and receptive reading (Tests A\'C\'), as well as of a Final Test of Oral Reading. The results showed that the direct training of phonemes (Conditions I and II) was effective in establishing recombinative reading with high scores and low variability within and among participants. Regarding the moment of the insertion of phoneme training on the procedure, the conclusion is that this is an important variable and enables the observation of different results among participants submitted to Conditions I and II. The results suggest that participants undergoing Condition II (Overlapping) were those with greater recombinative speed and higher rates of recombinative reading, while participants submitted to Condition I (Prior) presented the lowest variability among themselves

Les travaux de recherche menés autour de la description de services Web utilisent de plus en plus des modèles sémantiques pour fournir une représentation interprétable automatiquement. Toutefois, nous avons décelé des lacunes dans les approches sémantiques actuelles qui engendrent ambiguïté et non pertinence au niveau de l’appariement et de la découverte de services Web. Pour remédier à ces lacunes nous proposons des contributions à la description et à la découverte de services Web sémantiques. En ce qui concerne la description de services, nous avons défini un langage basé sur une recommandation W3C. En plus d’une annotation métier sémantique des éléments d’un service, notre principale contribution à la description sémantique consiste à spécifier la nature de ces annotations en utilisant une ontologie technique que nous avons définie. Cette ontologie met en relation plusieurs concepts sémantiques de services Web que nous avons identifiés dans des approches existantes et intègrera d’autres concepts qu’on définira ultérieurement sans pour autant modifier notre langage de description ou nos techniques d’appariement associées. Nous avons également défini un algorithme d’appariement entre une requête de service et les descriptions des services publiés. Cet algorithme se base sur un appariement entre éléments d’une requête et un service publié et trois techniques d’agrégation des résultats d’appariements élémentaires. L’algorithme tire avantage de la description sémantique que nous avons définie. Il a été mis en œuvre dans un annuaire de services Web sémantiques et a été également comparé aux algorithmes de référence. Les expérimentations montrent clairement l’efficacité de notre approche en termes de temps de réponse et de précision / Researches conducted around Web service description use more and more of semantic models to provide an automatically interpretable representation. However, we identified gaps in current approaches that generate semantic ambiguity and impertinence at Web service matching and discovery. To address these shortcomings we propose contributions about semantic Web service description and discovery. As for the Web services description, we have defined a language based on a W3C Recommendation. In addition to a semantic business annotation of service components, our main contribution about the semantic description is to specify the nature of these annotations using a technical ontology that we have defined. This ontology merges several semantic concepts of web services that we identified in existing approaches and may include other concepts that can be defined later without changing our description language or our matching techniques. We also defined a matching algorithm between a service request and published service descriptions. This algorithm is based on matching between elements of a service request and descriptions of published services. This matching is may be computed by three aggregation techniques of the results of those elements’ matching. The algorithm takes advantage of the semantic description we have defined. It was implemented in a semantic web services registry and was also compared to referenced algorithms. The experiments clearly demonstrate the effectiveness of our approach in terms of response time and precision

In this thesis, we explore two different approaches to causal inferences. The traditional approach models the theoretical relationship between the outcome variables and their explanatory variables, i.e., the science, at the same time as the systematic differences between treated and control subjects are modeled, i.e., the assignment mechanism. The alternative approach, based on Rubin's Causal Model (RCM), makes it possible to model the science and the assignment mechanism separately in a two-step procedure. In the first step, no outcome variables are used when the assignment mechanism is modeled, the treated students are matched with similar control students using this mechanism, and the models for the science are determined. Outcome variables are only used in the second step when these pre-specified models for the science are fitted. In the first paper, we use the traditional approach to evaluate whether a husband is more prone to quit smoking when his wife quits smoking than he would have been had his wife not quit. We find evidence that this is the case, but that our analysis must rely on restrictive assumptions. In the subsequent two papers, we use the alternative RCM approach to evaluate if a Harvard freshman who does not smoke (observed potential outcome) is more prone to start smoking when he shares a suite with at least one smoker, than he would have been had he shared a suite with only smokers (missing potential outcomes). We do not find evidence that this is the case, and the small and insignificant treatment effect is robust against various assumptions that we make regarding covariate adjustments and missing potential outcomes. In contrast, we do find such evidence when we use the traditional approach previously used in the literature to evaluate peer effects relating to smoking, but the treatment effect is not robust against the assumptions that we make regarding covariate adjustments. These contrasting results in the two latter papers allow us to conclude that there are a number of advantages with the alternative RCM approach over the traditional approaches previously used to evaluate peer effects relating to smoking. Because the RCM does not use the outcome variables when the assignment mechanism is modeled, it can be re-fit repeatedly without biasing the models for the science. The assignment mechanism can then often be modeled to fit the data better and, because the models for the science can consequently better control for the assignment mechanism, they can be fit with less restrictive assumptions. Moreover, because the RCM models two distinct processes separately, the implications of the assumptions that are made on these processes become more transparent. Finally, the RCM can derive the two potential outcomes needed for drawing causal inferences explicitly, which enhances the transparency of the assumptions made with regard to the missing potential outcomes. / Diss. Stockholm : Handelshögskolan, 2006 S. 1-13: sammanfattning, s. [15]-161: 4 uppsatser

近年來，越來越多單身男女希望能夠透過網路交友平台找到自己的另一半。本論文考慮一個網路交友平台的經營，期望能夠讓每位參與者都找到適合彼此的另一半。我們使用工作指派問題的數學模型整合配對問題及穩定室友問題的概念建構男女配對問題的數學模型。並且考慮多位交友對象、拒絕對象與分級制度等問題，分別提出不同的數學模型。最後，我們使用隨機產生的資料模擬參與者的雙向配度，以GAMS軟體求解，分析不同的配對結果，亦探討不同模型的難易度及求解所需之運算時間。 / In recent years, more and more single women and men hope that they can find their Mr. or Mrs. Right through the internet dating platform. This paper considers the operation of an internet dating platform which expects each participant to find the other half of each other. We propose mathematical models of the women and men matching problem by using the mathematical model of the assignment problem and integrating the idea of matching problem as well as the stable roommate problem. We also consider the problems of multiple dating objects, matching with rejection, and classification member. Finally, a simulate study will be performed by using the randomly generating data to simulate the two-way matching degree of each pair of participants. We analyze the different matching results obtained by the different models. We also present the difficulty of different models and the solution times.

I storstadsregionerna blir trafikläget allt mer ansträngt för vart år som går. Inflyttningen fortsätter i oförändrad takt och fler människor måste försöka samsas om samma utrymme. Situationen på vägarna börjar bli ohållbar och det måste till att dessa problem löses snart för att utvecklingen i regionerna inte ska stagnera. Möjligheter för ytterligare utbyignationer finns dock i en begränsad grad och man måste börja se till andra lösningar. Inom området för intelligenta transportsystem(ITS) erbjuds många nya tillämpningar där man med ny teknik försöker hitta lösningar till dagens trafikproblem. Ett led i detta är att samla in och distribuera information om restider på vägarna, för att försöka fördela trafiken mer jämt över hela vägnätet. Det finns olika metoder för att hämta in den här typen av information, men den här rapporten fokuserar sig vid att beskriva system baserat på Floating Car Data(FCD). Arbetet som beskrivs i rapporten har i huvudsak analyserat fyra olika restidsuppskattnings-modeller och jämfört dessa med varandra. Modellerna baserar sina beräkningar på observationer från oidentifierade fordon, dvs att observationerna inte har någon identitetsstämpel som kan kopplas till ett specifikt fordon. Två av modellerna betraktar länkarna som en helhet och utför beräkningarna med detta som grund, medan de två andra delar upp varje länk i mindre segment vilket skapar möjlighet för en större noggrannhet. Modellerna testades inledningsvis på simulerad data baserat på trafikmätningar i Göteborgstrakten. Alla beräkningar begränsades ner till länknivå och inte hela vägnät. Detta p.g.a. att det initialt var för komplicerat att skapa en map- matchingmetod som skulle krävas för genomföra beräkningar på olika länkar samtidigt. Efter genomförda tester på simulerad data prövades modellerna även på en reella datamängd hämtad från projektet Probe i Stockholmsområdet. Resultaten från de utförda testerna visar på att det inte skiljer sig nämnvärt i restidsuppskattningarna mellan de olika modellerna. Sträckan som valdes att analyseras i de simulerade fallen, påverkades inte av några större störningar eller flödesvariationer. Det resulterade i att alla modellerna genererade likvärdiga restider. Även i fallet med den reella datamängden, som innehöll större flödesvariationer över tiden, kunde de olika modellernas uppskattningar inte skiljas åt nämnvärt. Slutsatsen är att trafiken i allmänhet inte har så kraftiga förändringar i flödet över tiden, att det krävs särskilt avancerade modeller för att beräkna restider på länknivå. I alla fall inte om man bortser från incidenter. De framräknade restiderna och den information som dessa ger, bör främst användas för direkt trafikstyrning för att uppnå önskat resultat. Människor förlitar sig mer till sina egna erfarenheter i kända områden, så information av den här typen lämpar sig mer som hjälpmedel för den enskilde individen vid resor i okänd trafik.

Pattern matching is a well-established concept in the functional programming community. It provides the means for concisely identifying and destructuring values of interest. This enables a clean separation of data structures and respective functionality, as well as dispatching functionality based on more than a single value. Unfortunately, expressive pattern matching facilities are seldomly incorporated in present object-oriented programming languages. We present a seamless integration of pattern matching facilities in an object-oriented and dynamically typed programming language: Newspeak. We describe language extensions to improve the practicability and integrate our additions with the existing programming environment for Newspeak. This report is based on the first author’s master’s thesis.

This research deals with the second harmonic generation of Lamb waves in nonlinear elastic, homogeneous, isotropic plates. These waves find current applications in the field of ultrasonic, nondestructive testing and evaluation of materials. The second harmonic Lamb wave generation is investigated analytically in order to provide information on suitable excitation modes maximizing the second harmonic amplitude. Using an existing solution for the problem of second harmonic generation in wave guides, the solution is explained for the plate and examined as to the symmetry properties of the second harmonic wave, since published results are contradictory. It is shown that the cross-modal generation of a symmetric secondary mode by an antisymmetric primary mode is possible. Modes showing internal resonance, whose conditions are nonzero power flux from the primary wave and phase velocity matching, are shown to be most useful for measurements. In addition, group velocity matching is required. A material-independent analysis of the linear Lamb mode theory provides mode types satisfying all three requirements. Using the example of an aluminum plate, the found internally resonant modes are evaluated with regard to the rate of second harmonic generation and practical issues such as excitability and ease of measurement. Pros and cons of each mode type are presented.

<p>I storstadsregionerna blir trafikläget allt mer ansträngt för vart år som går. Inflyttningen fortsätter i oförändrad takt och fler människor måste försöka samsas om samma utrymme. Situationen på vägarna börjar bli ohållbar och det måste till att dessa problem löses snart för att utvecklingen i regionerna inte ska stagnera. Möjligheter för ytterligare utbyignationer finns dock i en begränsad grad och man måste börja se till andra lösningar. Inom området för intelligenta transportsystem(ITS) erbjuds många nya tillämpningar där man med ny teknik försöker hitta lösningar till dagens trafikproblem. Ett led i detta är att samla in och distribuera information om restider på vägarna, för att försöka fördela trafiken mer jämt över hela vägnätet. Det finns olika metoder för att hämta in den här typen av information, men den här rapporten fokuserar sig vid att beskriva system baserat på Floating Car Data(FCD). </p><p>Arbetet som beskrivs i rapporten har i huvudsak analyserat fyra olika restidsuppskattnings-modeller och jämfört dessa med varandra. Modellerna baserar sina beräkningar på observationer från oidentifierade fordon, dvs att observationerna inte har någon identitetsstämpel som kan kopplas till ett specifikt fordon. Två av modellerna betraktar länkarna som en helhet och utför beräkningarna med detta som grund, medan de två andra delar upp varje länk i mindre segment vilket skapar möjlighet för en större noggrannhet. Modellerna testades inledningsvis på simulerad data baserat på trafikmätningar i Göteborgstrakten. Alla beräkningar begränsades ner till länknivå och inte hela vägnät. Detta p.g.a. att det initialt var för komplicerat att skapa en map- matchingmetod som skulle krävas för genomföra beräkningar på olika länkar samtidigt. </p><p>Efter genomförda tester på simulerad data prövades modellerna även på en reella datamängd hämtad från projektet Probe i Stockholmsområdet. Resultaten från de utförda testerna visar på att det inte skiljer sig nämnvärt i restidsuppskattningarna mellan de olika modellerna. Sträckan som valdes att analyseras i de simulerade fallen, påverkades inte av några större störningar eller flödesvariationer. Det resulterade i att alla modellerna genererade likvärdiga restider. Även i fallet med den reella datamängden, som innehöll större flödesvariationer över tiden, kunde de olika modellernas uppskattningar inte skiljas åt nämnvärt. </p><p>Slutsatsen är att trafiken i allmänhet inte har så kraftiga förändringar i flödet över tiden, att det krävs särskilt avancerade modeller för att beräkna restider på länknivå. I alla fall inte om man bortser från incidenter. De framräknade restiderna och den information som dessa ger, bör främst användas för direkt trafikstyrning för att uppnå önskat resultat. Människor förlitar sig mer till sina egna erfarenheter i kända områden, så information av den här typen lämpar sig mer som hjälpmedel för den enskilde individen vid resor i okänd trafik.</p>