Title: Binary Signed Digit Representations of Integers in Cryptanalysis of Hash Functions Author: Jiří Vábek Department: Department of Algebra Supervisor: doc. RNDr. Jiří Tůma, DrSc., Department of Algebra Abstract: The work summarizes two main papers, A New Type of 2-block Colli- sions in MD5 and On the Number of Binary Signed Digit Representations of a Given Weight, while containing also the wider introduction to the topic of crypt- analysis of MD5 and binary signed digit representations (BSDR's). In the first paper we have implemented and applied Stevens algorithm to the newly proposed initial message differences and constructed a new type of collisions in MD5. In the second paper we have introduced and proved a new improved bound for the number of optimal BSDR's and also a new recursive bound for the number of BSDR's of a given integer with a given overweight. In addition to the results in mentioned papers, the generalized result is stated with the new bound for the number of optimal D-representations of natural numbers with D = {0, 1, 3}. Keywords: hash function, MD5, binary signed digit representation (BSDR), non- adjacent form (NAF) 1

abstract: The development of advanced, anthropomorphic artificial hands aims to provide upper extremity amputees with improved functionality for activities of daily living. However, many state-of-the-art hands have a large number of degrees of freedom that can be challenging to control in an intuitive manner. Automated grip responses could be built into artificial hands in order to enhance grasp stability and reduce the cognitive burden on the user. To this end, three studies were conducted to understand how human hands respond, passively and actively, to unexpected perturbations of a grasped object along and about different axes relative to the hand. The first study investigated the effect of magnitude, direction, and axis of rotation on precision grip responses to unexpected rotational perturbations of a grasped object. A robust "catch-up response" (a rapid, pulse-like increase in grip force rate previously reported only for translational perturbations) was observed whose strength scaled with the axis of rotation. Using two haptic robots, we then investigated the effects of grip surface friction, axis, and direction of perturbation on precision grip responses for unexpected translational and rotational perturbations for three different hand-centric axes. A robust catch-up response was observed for all axes and directions for both translational and rotational perturbations. Grip surface friction had no effect on the stereotypical catch-up response. Finally, we characterized the passive properties of the precision grip-object system via robot-imposed impulse perturbations. The hand-centric axis associated with the greatest translational stiffness was different than that for rotational stiffness. This work expands our understanding of the passive and active features of precision grip, a hallmark of human dexterous manipulation. Biological insights such as these could be used to enhance the functionality of artificial hands and the quality of life for upper extremity amputees. / Dissertation/Thesis / Ph.D. Mechanical Engineering 2013

Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-30T11:13:52Z No. of bitstreams: 2 Dissertação - Antônio Dionísio Feitosa Noronha Filho - 2013.pdf: 1195605 bytes, checksum: 6407e61f5c39652f43701aff78788bfd (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-30T12:42:48Z (GMT) No. of bitstreams: 2 Dissertação - Antônio Dionísio Feitosa Noronha Filho - 2013.pdf: 1195605 bytes, checksum: 6407e61f5c39652f43701aff78788bfd (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-30T12:42:48Z (GMT). No. of bitstreams: 2 Dissertação - Antônio Dionísio Feitosa Noronha Filho - 2013.pdf: 1195605 bytes, checksum: 6407e61f5c39652f43701aff78788bfd (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-03-15 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Digital diseases worries livestock industry and arouse interest in extensionists because of the economic losses and difficult control. Losses come from decrease in productive and reproductive performance and, in some cases, the premature culling of high value breeding animals. Besides these, lameness causes negative impact on animal welfare. Digital diseases assume different characteristics in distinct production systems, requiring specific solutions that fits each farms condition. Innovative treatments have been discussed, but are not always economically viable, however, in last years in Veterinary Medicine has increased the interest on the possibility of applying cell therapy in the treatment of diseases related to the locomotor systems, including digital diseases. In the equine, it has been studied its use in the repair of tendineous, articular and osseous lesions, and the perspective of application in other important diseases like laminitis. Considering the importance of digital diseases, especially laminitis, for cattle, cell therapy can represent an additional option for treatment. This study evaluated the development of digital lesions in cattle intensively managed and its response to the treatment with bone marrow mononuclear cells. Were used 15 animals, male, cross-bred (Bos taurus X Bos indicus), healthy, aging about 12 months and with average weight of151,6 ± 24,65 kg, divided in two groups (GT, n=7, GC, n=8). The study was developed in three stages divided in evaluation moments. On first stage, on second month of confinement, after adjustment of management over concrete floor and feeding of corn silage and concentrate, hooves were trimmed and started evaluation of digital disease wich extended to the tenth month. At this time, were observed digital lesions that developed in the period, their influence over behavior and was conducted radiographic examinations trying to establish relationship between external and internal lesions of digits. After ten months of study all animals had its hooves trimmed and all digital lesions, in decorrence of management, were surgically treated. At this time, started last stage in wich animals received cell therapy. To obtain material needed for the protocol, were harvested samples of bone marrow from animals belonging to treatment group (GT). After this, mononuclear cells were isolated and samples were injected at jugular vein. In the protocol for bone marrow harvest and isolation of mononuclear cells was used Ficoll-Paque. On animals from control group (GC), their lesions were treated during hoof trimming, but all anials were evaluated at twelfth month. To certify the effect of cell therapy, besides clinical examination, identification of possible recidivance or new lesions, were done histological examination for occurrence of hyperemia, hemorrhages or edema on dermis, presence of white blood cells inside or outside vessels and necrosis of basal cells from epidermis, and radiographic examination. On direct inspection were observed expressive occurrence of digital lesions like heel horn erosion, haematoma and erosions of sole and white line disease, however with no difference between groups. Major changes in behavior observed along time were decrease in eating time and increase in times lying down and in leisure. Radiographic evaluation didn´t show signs of distal phalanx rotation suggesting external alterations may not be related to internal alterations. Protocols for bone marrow aspiration and for cell isolation using Ficoll-Paque were effective, resulting in obtainance of mononuclear cells with satisfatory viability. But, since it wasn´t observed significative differences between groups related to digital lesions, histological and radiographical examinations, the reoccurrence and appearance of new lesions after cell therapy cannot be related to this treatment, because seem to be more related to management conditions. It can be concluded that applying of bone marrow derived mononuclear cells at jugular vein didn´t show benefits as auxiliary treatment of digital lesions in cattle. The control of risk factors and site of cell application seem to explain the apparent failure of the therapeutic protocol used. / As doenças digitais causam preocupação ao setor produtivo e despertam grande interesse nos técnicos ligados à bovinocultura em função do impacto econômico e do difícil controle. Os prejuízos decorrem de queda no desempenho produtivo, reprodutivo, tratamento oneroso e em alguns casos descarte prematuro de animais de alto mérito genético. Além disso, ameaçam seriamente o bem estar animal. Essas doenças assumem características distintas nos diversos sistemas de produção, o que em alguns casos demandam soluções específicas e tratamentos que atendam a realidade do criatório. Tratamentos inovadores têm sido discutidos, mas nem sempre são viáveis economicamente. Contudo, nos últimos anos, na Medicina Veterinária cresce o interesse na possibilidade de se empregar a terapia celular, que poderia ser aplicada como auxiliar no tratamento de várias enfermidades do aparelho locomotor, incluindo as enfermidades digitais. Em equinos, já se tem investigado seu emprego no reparo de lesões tendíneas, articulares e ósseas, havendo ainda a perspectiva de aplicação em outras doenças importantes como a laminite. Portanto, considerando a importância que as doenças digitais, em especial a laminite, assumem na espécie bovina, a terapia celular pode representar uma ferramenta adicional no tratamento. Esta pesquisa objetivou avaliar o desenvolvimento de lesões digitais em bovinos manejados intensivamente e sua resposta ao tratamento com células mononucleares da medula óssea. Foram empregados 15 bovinos machos, mestiços (Bos taurus X Bos indicus), hígidos com idade inicial aproximada de 12 meses e peso corporal médio de 151,6 ± 24,65 kg, alocados em dois grupos (Grupo tratamento, GT, n=7; Grupo controle, GC, n=8). O estudo foi desenvolvido em três etapas divididos em momentos de avaliação. Na primeira etapa, no 2o mês de confinamento após ajustar o manejo em piso de concreto e a alimentação a base de silagem de milho e concentrado, realizou-se ajuste nas medidas digitais dos animais e iniciou-se o acompanhamento para avaliar a ocorrência de doenças digitais, que se estendeu até o décimo mês. Nesse período, foram realizadas avaliações para diagnosticar as enfermidades que eventualmente surgissem. Estudou-se a influência delas sobre o comportamento diário dos bovinos e procedeu-se a análise macroscópica das lesões digitais e a avaliação radiográfica para se tentar estabelecer uma relação entre as lesões externas e internas dos dígitos. Após dez meses de confinamento, todos os animais tiveram as medidas digitais novamente ajustadas e as enfermidades digitais que surgiram na etapa anterior, em decorrência do manejo, foram tratadas cirurgicamente. Nesse momento iniciou-se a ultima etapa na qual os animais receberam a terapia celular. Para se obter o material necessário que o protocolo exigia colheu-se medula óssea dos bovinos pertencentes ao grupo tratamento (GT), na sequência, as células mononucleares foram isoladas e uma amostra destas foram aplicadas pela veia jugular em cada animal. No protocolo de colheita da medula óssea e isolamento celular empregou-se o Ficoll-Paque®. O grupo controle (GC) foi apenas submetido ao tratamento das lesões e tiveram as medidas dos cascos ajustadas, mas os bovinos de ambos os grupos foram reavaliados ao final do 12o mês do estudo. Para certificar o efeito da terapia celular, além do exame clínico, identificação de possível recrudescimento ou surgimento de novas lesões, realizou-se exame radiográfico, avaliação histológica da região coronária para avaliar presença de hiperemia, hemorragia ou edema da derme, presença de células brancas dentro ou fora dos vasos e necrose de células basais da epiderme. Na avaliação macroscópica foi observada ocorrência expressiva de lesões digitais como erosão de talão, hematoma e erosão de sola e lesão de linha branca, porém, sem diferenças entre grupos. As principais alterações de comportamento observadas ao longo das avaliações foram a redução no tempo de alimentação e aumento nos tempos em ócio e em decúbito, mas, sem diferenças entre grupos tratamento e controle. A avaliação radiográfica não mostrou ter ocorrido a rotação da falange distal indicando que as lesões externas podem não ter relação com as alterações internas. Os resultados obtidos indicam que o protocolo de aspiração de medula óssea e de isolamento celular usando Ficoll-Paque® foi eficaz, resultando na obtenção de células mononucleares com rendimento e viabilidade satisfatórios. Mas, como não foram observadas diferenças significativas entre grupos, tanto com relação as enfermidades como em relação aos resultados histológicos e radiográficos as recidivas ou o aparecimento de novas lesões após a terapia celular não podem ser imputadas a esse tratamento, pois parecem ter relação com o manejo. Conclui-se que a aplicação de células mononucleares da medula óssea pela veia jugular não apresentou benefícios no tratamento auxiliar de lesões digitais em bovinos, sendo que aspectos relacionados ao controle dos fatores de risco e local de aplicação das células parecem explicar a aparente falta de sucesso do protocolo terapêutico empregado.

Throughout this project, we perform a multivariate analysis of the parameters of a long short-term memory (LSTM) system for handwritten digit recognition in order to understand the model’s behaviour. In particular, we are interested in explaining how this behaviour precipitate from its parameters, and what in the network is responsible for the model arriving at a certain decision. This problem is often referred to as the interpretability problem, and falls under scope of Explainable AI (XAI). The motivation is to make AI systems more transparent, so that we can establish trust between humans. For this purpose, we make use of the MNIST dataset, which has been successfully used in the past for tackling digit recognition problem. Moreover, the balance and the simplicity of the data makes it an appropriate dataset for carrying out this research. We start by investigating the linear output layer of the LSTM, which is directly associated with the models’ predictions. The analysis includes several experiments, where we apply various methods from linear algebra such as principal component analysis (PCA) and singular value decomposition (SVD), to interpret the parameters of the network. For example, we experiment with different setups of low-rank approximations of the weight output matrix, in order to see the importance of each singular vector for each class of the digits. We found out that cutting off the fifth left and right singular vectors the model practically losses its ability to predict eights. Finally, we present a framework for analysing the parameters of the hidden layer, along with our implementation of an LSTM based variational autoencoder that serves this purpose. / I det här projektet utför vi en multivariatanalys av parametrarna för ett long short-term memory system (LSTM) för igenkänning av handskrivna siffror för att förstå modellens beteende. Vi är särskilt intresserade av att förklara hur detta uppträdande kommer ur parametrarna, och vad i nätverket som ligger bakom den modell som kommer fram till ett visst beslut. Detta problem kallas ofta för interpretability problem och omfattas av förklarlig AI (XAI). Motiveringen är att göra AI-systemen öppnare, så att vi kan skapa förtroende mellan människor. I detta syfte använder vi MNIST-datamängden, som tidigare framgångsrikt har använts för att ta itu med problemet med igenkänning av siffror. Dessutom gör balansen och enkelheten i uppgifterna det till en lämplig uppsättning uppgifter för att utföra denna forskning. Vi börjar med att undersöka det linjära utdatalagret i LSTM, som är direkt kopplat till modellernas förutsägelser. Analysen omfattar flera experiment, där vi använder olika metoder från linjär algebra, som principalkomponentanalys (PCA) och singulärvärdesfaktorisering (SVD), för att tolka nätverkets parametrar. Vi experimenterar till exempel med olika uppsättningar av lågrangordnade approximationer av viktutmatrisen för att se vikten av varje enskild vektor för varje klass av siffrorna. Vi upptäckte att om man skär av den femte vänster och högervektorn förlorar modellen praktiskt taget sin förmåga att förutsäga siffran åtta. Slutligen lägger vi fram ett ramverk för analys av parametrarna för det dolda lagret, tillsammans med vårt genomförande av en LSTM-baserad variational autoencoder som tjänar detta syfte.

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The field of entrepreneurship is rapidly advancing and matures as a discipline that receives substantial amount of attention. One popular area of research in the discipline of entrepreneurship is to investigate one’s intent to start a business, which is entrepreneurial intention. This is an important construct that warrants ongoing research because entrepreneurial intention is not only a great predictor of entrepreneurial behavior but also an important step in the process of becoming an entrepreneur. The present study, based on a sample of 321 subjects along with 264 observers, makes five contributions to the entrepreneurship literature. First, I examined the psychometric property of entrepreneurial take-over intention and found that it is a construct different from entrepreneurial start-up intention. Second, the results demonstrated that risk propensity and proactive personality are positive predictors of entrepreneurial start-up and take-over intentions, whereas cognitive ability is a negative predictor of entrepreneurial start-up and take-over intentions. Rebelliousness is a positive predictor of entrepreneurial take-over intention and also has an inverted U-shaped relationship with entrepreneurial take-over intention. Third, entrepreneurial self-efficacy mediates the relationship between three individual traits (i.e., emotional intelligence, risk propensity, and proactive personality) and entrepreneurial start-up and take-over intentions. Need for cognition mediates the relationship between two individual traits (i.e., cognitive ability and proactive personality) and entrepreneurial start-up intention. Fourth, 2D:4D ratio (a proxy measure for prenatal testosterone exposure level) negatively predicts risk propensity. There also exist two two-step mediations from 2D:4D ratio to both entrepreneurial start-up and take-over intentions through risk propensity and entrepreneurial self-efficacy. Fifth, the results suggest that observer ratings of individual traits only contribute modest incremental validity above and beyond self-reported ratings of them in predicting entrepreneurial start-up and take-over intentions. I discuss implications, limitations, and future directions informed by the present study.

In his keynote address to the National Council of Teachers of Mathematics research pre-session, Sloane (2006b) challenged mathematics education researchers to ‘quantify qualitative insights’. This quasi-experimental study used blended methods to investigate the development of two-digit addition and subtraction strategies. Concurrent classroom teaching experiments were conducted in two intact first grade classrooms (n = 41) in a mid-Atlantic American public school. From a pragmatic emergent perspective, design research (Gravemeijer & Cobb, 2006) was used to develop local instructional theory. An amplified theoretical framework for early base-ten strategies is explicated. Multilevel modelling for repeated measures was used to evaluate the differences in strategy usage between classes across occasions and the association of particular pedagogical practices with the emergence of incrementing and decrementing by ten (N10) or decomposition (1010) strategies (Beishuizen, Felix, & Beishuizen, 1990).The two matched classes were not different in terms of gender, poverty, race, pre-assessment performance, and special education services. After the first unit of instruction with differentiated pedagogical tools, the collection class was significantly (p = .001) more likely to use 1010 than the linear class. No difference was demonstrated during the post-assessment. Students in both classes were more likely to use N10 during the last structured interview than in the first (p < .0001). Furthermore, there was no difference between the two classes in using any advanced strategy; however, students in both classes were more likely to use an advanced strategy at the conclusion of the study than they were initially (p = .033). The order of emergence of 1010 and N10 was not associated with the ability to develop both strategies, but there was an association (p < .001) between use of an advanced strategy and success on a district-mandated written assessment of two-digit addition and subtraction.Two original instructional sequences of contextually-based investigations are presented. Protocols transcribed from videotaped lessons and dynamic assessment interviews are presented to illuminate specific constructs detected and to illustrate the pedagogical techniques. An amplified framework for early place value constructs is proposed. Recommendations for future studies, curricular changes, and the need of early intervention are discussed.

<p>Master thesis work at ITN (Department of Science and Technology) in the areas of A/D-construction and RF-circuit design. Major goal of project were to research suitable possibilities for implementations of direct conversion in transceivers operating in the 160MHz band, theoretic study followed by development of components in the construction environment Cadence. Suitable A/D- converter and other important parts were selected at the end of the theoretic study. Subsampling technique was applied to make A/D sample requirements more realistic to achieve. Besides lowering requirements on A/D-converter it allows a more simple construction, which saves more components than subsampling adds. Subsampling add extra noise, because of that an A/D-converter based on the RSD algorithm was chosen to improve error rate. To achieve high bit-processing rate compared to the used number of transistors, pipeline structure were selected as conversion method. The receiver was that part which gained largest attention because it’s the part which is most interesting to optimise. A/D-conversion is more difficult to construct than D/A conversion, besides there’s more to gain from eliminating mixers in the receiver than in the transmitter.</p>

Master thesis work at ITN (Department of Science and Technology) in the areas of A/D-construction and RF-circuit design. Major goal of project were to research suitable possibilities for implementations of direct conversion in transceivers operating in the 160MHz band, theoretic study followed by development of components in the construction environment Cadence. Suitable A/D- converter and other important parts were selected at the end of the theoretic study. Subsampling technique was applied to make A/D sample requirements more realistic to achieve. Besides lowering requirements on A/D-converter it allows a more simple construction, which saves more components than subsampling adds. Subsampling add extra noise, because of that an A/D-converter based on the RSD algorithm was chosen to improve error rate. To achieve high bit-processing rate compared to the used number of transistors, pipeline structure were selected as conversion method. The receiver was that part which gained largest attention because it’s the part which is most interesting to optimise. A/D-conversion is more difficult to construct than D/A conversion, besides there’s more to gain from eliminating mixers in the receiver than in the transmitter.

Finite impulse response (FIR) digital filters are frequently used in many digital signal processing and communication applications, such as IS-95 CDMA, Digital Mobile Phone Systems (D-AMPS), etc. FIR filter achieves the frequency response of system requirement using a series of multiplications and additions. Previous papers on FIR hardware implementations usually focus on reducing area and delay of the multiple constant multiplications (MCM) through common sub-expression elimination (CSE) in the transpose FIR filter structure. In this thesis, we first perform optimization for the quantization of FIR filter coefficients that satisfy the target frequency response. Then suitable encoding methods are adopted to reduce the height of the partial products of the MCM in the direct FIR filter structure. Finally, by jointly considering the errors in the truncated multiplications and additions, we can design the hardware-efficient FIR filter that meets the bit accuracy requirement. Experimental results show that although CSE in the transpose FIR structure can reduce more area in MCM, the direct form takes smaller area in registers. Compared with previous approaches, the proposed FIR implementations with direct form has the minimum area cost.