Development in information and communication technology has increased the attention of personalization in the 21st century and the benefits to both marketers and customers are claimed to be many. The need to efficiently deliver personalized content in different web applications has increased the interest in the field of machine learning. In this thesis project, the aim is to develop a decision model that autonomously optimizes a commercial web service to increase the click through rate. The model should be based on previously collected data about previous usage of the web service. Different requirements for efficiency and storage must be fulfilled at the same time as the model should produce valuable results. An algorithm for a binary decision tree is presented in this report. The evolution of the binary tree is controlled by an entropy minimizing heuristic approach together with three specified stopping criteria. Tests on both synthetic and real data sets were performed to evaluate the accuracy and efficiency of the algorithm. The results showed that the running time is dominated by different parameters depending on the sizes of the test sets. The model is capable of capturing inherent patterns in the the available data.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13812号 / 工博第2916号 / 新制||工||1431(附属図書館) / 26028 / UT51-2008-C728 / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 椹木 哲夫, 教授 吉村 允孝, 教授 松原 厚 / 学位規則第4条第1項該当

A method of estimating the relative position and orientation of a known target satellite is presented, using only passive imagery. Such a method is intended as a prelude to a system required in future autonomous satellite docking missions. Using a single monocular image, and utilising knowledge of the target spacecraft, estimation of the target's six relative rotation and translation parameters with respect to the camera are found. Pose estimation is divided into modular sections. Each frame is processed to detect the major lines in the image, and correspondence information between detected lines and a-priori target information is estimated, resulting in a list of line-to-model correspondences. This correspondence information is used to estimate the pose of the target required to produce such a correspondence list. Multiple possible pose estimates are generated and tested, where each estimate contains the three rotation and translation parameters. The best estimates go through to the least-squares minimisation phase, which reduces estimation error and provides statistical information for multi-frame filtering. The final estimate vector and covariance matrix is the end result for each frame. Estimates of the target location over time allow the relative orbit parameters of the target to be estimated. Location estimates are filtered to fit an orbit model based on Hill's Equations, and statistical information gathered with each estimate is including in the filter process when estimating the orbit parameters. These orbit parameters allow prediction of the target location with time, which will enable mission planning and safety analysis of potential orbit manoeuvres in close proximity to the target. Testing is carried out by a detailed simulation system, which renders accurate images of the target satellite given the true pose of the target with respect to the inertial reference frame. The rendering software used takes into account lighting conditions, reflections, shadowing, specularity, and other considerations, and further post-processing is involved to produce a realistic image. Target position over time is modelled on orbit dynamics with respect to a defined inertial frame. Transformation between inertial, target, and camera frames of reference are dealt with, to transform a rotating target in the inertial frame to the apparent rotation in the camera frame.

An increasing number of intelligent information agents employ Nearest Neighbour learning algorithms to provide personalised assistance to the user. This assistance may be in the form of recognising or locating documents that the user might find relevant or interesting. To achieve this, documents must be mapped into a representation that can be presented to the learning algorithm. Simple heuristic techniques are generally used to identify relevant terms from the documents. These terms are then used to construct large, sparse training vectors. The work presented here investigates an alternative representation based on sets of terms, called set-valued attributes, and proposes a new family of Nearest Neighbour learning algorithms that utilise this set-based representation. The importance of discarding irrelevant terms from the documents is then addressed, and this is generalised to examine the behaviour of the Nearest Neighbour learning algorithm with high dimensional data sets containing such values. A variety of selection techniques used by other machine learning and information retrieval systems are presented, and empirically evaluated within the context of a Nearest Neighbour framework. The thesis concludes with a discussion of ways in which attribute selection and dimensionality reduction techniques may be used to improve the selection of relevant attributes, and thus increase the reliability and predictive accuracy of the Nearest Neighbour learning algorithm.

Neural machine translation has been lately established as the new state of the art in machine translation, especially with the Transformer model. This model emphasized the importance of self-attention mechanism and sug- gested that it could capture some linguistic phenomena. However, this claim has not been examined thoroughly, so we propose two main groups of meth- ods to examine the relation between these two. Our methods aim to im- prove the translation performance by directly manipulating the self-attention layer. The first group focuses on enriching the encoder with source-side syn- tax with tree-related position embeddings or our novel specialized attention heads. The second group is a joint translation and parsing model leveraging self-attention weight for the parsing task. It is clear from the results that enriching the Transformer with sentence structure can help. More impor- tantly, the Transformer model is in fact able to capture this type of linguistic information with guidance in the context of multi-task learning at nearly no increase in training costs. 1

The purpose of the present study was to investigate response allocation amongst two concurrently available computerized slot machines, one dispensing Losses Disguised as Wins (LDWs) while the other did not. Both payouts were equal in the beginning and became consistently worst for the LDW machine by lowering the payout each phase. LDWs are slot machine outcomes, participants bet on a slot machine and win back less than their wager. This may be a problem because participants may react to LDWs as a win, misleading the participant to think they are winning more than they actually are. In the present study the LDW outcome payout started at 80 percent payback and decrease by 20 percent each phase and non LDW, maintained at 400 percent payback over 12 percent of the trials. Twenty individuals were recruited by the researcher. Results indicated that a higher percentages of spins were allocated to the machine dispensing LDW. These results suggest that gamblers have a preference for LDW machines because of the reinforcement of the misleading factors that may indicated a win. Keywords: Gambling, LDW, slot machine, visual basic

AN ABSTRACT OF THE THESIS OF Katelyn Louise Decker, Master of Science Degree in Behavior Analysis and Therapy, presented on April 30, 2015, at Southern Illinois University TITLE: EFFECTS OF GAMBLING OUTCOMES ON LEVEL OF IMPULSIVITY MAJOR PROFESSOR: Dr. Mark R. Dixon The effects of exposure to winning and losing gambling outcomes on levels of impulsivity among non-gamblers were investigated in a within-subjects experimental design with randomization of treatment phases. Participants included 20 non-gamblers (10 male, 10 female), 18 years or older, selected from a sample of 40 volunteers who completed the South Oaks Gambling Screen (Lesieur & Blume, 1987) and received a score of 0, indicating no predictors of potential pathological gambling. Dependent measures of levels of impulsivity were recorded using an abbreviated version of the delayed discounting questionnaire described by Dixon et al. (2003). Derived k-values were calculated by fitting indifference points at each delay to the hyperbolic equation proposed by Mazur (1987) and average k-value was calculated for each participant across delays. Participants were exposed to both winning and losing outcomes by completing 25 trials within a slot-machine task programmed in Microsoft Visual Basic Express Edition 2008 (Maclin, et al., 2006, p. 127-154). Results were subjected to statistical analysis to determine whether a statistically significant, functional relationship existed between increases and decreases in level of impulsivity (k-value) in comparison to baseline. Across all participants, regardless of order of experimental conditions, results indicated a more than 26% decrease (-82.20-3133.33) in level of impulsivity (0-2.1694) following a losing outcome and a more than 24% decrease (-89.95-3300) in level of impulsivity (0-2.1694) following a winning outcome in comparison to baseline (0-2.3056). Results are consistent with the hypothesis that exposure to winning outcomes decrease impulsivity, but inconsistent with the hypothesis that exposure to losing outcomes increase impulsivity. Historical perspectives of pathological gambling, social impacts of gambling disorder, and trait and state-dependent perspectives of impulsivity are discussed. Potential implications for further research using delayed discounting measures are provided, as well as potential limitations of the present study. Keywords: gambling, impulsivity, delayed discounting, slot-machine, outcomes

Methods of compression-based text classification have proven their usefulness for various applications. However, in some classification problems, such as spam filtering, a classifier confronts one or many adversaries willing to induce errors in the classifier's judgment on certain kinds of input. In this thesis, we consider the problem of finding thrifty strategies for character-based text modification that allow an adversary to revert classifier's verdict on a given family of input texts. We propose three statistical statements of the problem that can be used by an attacker to obtain transformation models which are optimal in some sense. Evaluating these three techniques on a realistic spam corpus, we find that an adversary can transform a spam message (detectable as such by an entropy-based text classifier) into a legitimate one by generating and appending, in some cases, as few additional characters as 20% of the original length of the message.

Made available in DSpace on 2016-08-29T15:33:14Z (GMT). No. of bitstreams: 1 tese_4163_.pdf: 479699 bytes, checksum: 04f01a137084c0859b4494de6db8b3ac (MD5) Previous issue date: 2011-02-23 / Classificadores do tipo máquina de vetores de suporte (SVM) são atualmente considerados uma das técnicas mais poderosas para se resolver problemas de classificação com duas classes. Para aumentar o desempenho alcançado por classificadores SVM individuais, uma abordagem bem estabelecida é usar uma combinação de SVMs, a qual corresponde a um conjunto de classificadores SVMs que são, simultaneamente, individualmente precisos e coletivamente divergentes em suas decisões. Este trabalho propõe uma abordagem para se criar combinações de SVMs, baseada em um processo de três estágios. Inicialmente, são usadas execuções complementares de uma busca baseada em algoritmos genéticos (GEFS), com o objetivo de investigar globalmente o espaço de características para definir um conjunto de subconjuntos de características. Em seguida, para cada um desses subconjuntos de características definidos, uma SVM que usa parâmetros otimizados é construída. Por fim, é empregada uma busca local com o objetivo de selecionar um subconjunto otimizado dessas SVMs, e assim formar a combinação de SVMs que é finalmente produzida. Os experimentos foram realizados num contexto de detecção de defeitos em máquinas industriais. Foram usados 2000 exemplos de sinais de vibração de moto bombas instaladas em plataformas de petróleo. Os experimentos realizados mostram que o método proposto para se criar combinação de SVMs apresentou um desempenho superior em comparação a outras abordagens de classificação bem estabelecidas.

Made available in DSpace on 2014-06-11T19:35:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-11Bitstream added on 2014-06-13T19:05:49Z : No. of bitstreams: 1 almeida_jlcn_dr_guara.pdf: 2749824 bytes, checksum: 914ada61e3a445e7cda7ed446f711961 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As máquinas síncronas de ímãs permanentes têm a vantagem de não consumir energia para a criação do campo magnético no rotor. O propósito específico desta Tese é o projeto, a construção e a avaliação de uma máquina com grande número de polos, de enrolamentos concentrados, com ímãs permanentes inseridos no interior do rotor, com duas formas geométricas diferentes: um com ímãs alinhados e a outra com ímãs inclinados axialmente. As justificativas para este estudo foram a possibilidade de eliminação de multiplicadores mecânicos de velocidade e sistemas auxiliares de excitação em centrais geradoras de energia. O projeto usou um motor de indução trifásico com rotor gaiola de esquilo de 250W de 12 polos. Partindo dos próprios dados construtivos do estator, calculou-se a densidade de fluxo magnético, especificando os ímãs permanentes de neodímio. No desenvolvimento foi construído um novo rotor modular e simples. Posteriormente, a máquina foi avaliada em laboratório com o objetivo de verificar a quantidade e a qualidade da energia com a máquina atuando como gerador. Por último, os resultados encontrados na avaliação da máquina funcionando como gerador com ímãs alinhados revelaram distorção harmônica total (DHT) 16%, capacidade de geração 475W a 221V – 60Hz e como aspecto desfavorável o alto torque de travamento. Com ímãs inclinados, DHT de 7 a 8%, capacidade de geração de 236W a 195V – 60Hz e baixo torque de travamento. Este trabalho mostra que os ímãs inclinados modularmente são uma opção de máquinas elétricas com satisfatório desempenho da máquina como gerador de energia com razoável qualidade no contexto de geração distribuída de pequena potência. Além das condições técnicas têm-se o baixo custo e a manutenção reduzida do gerador com ímãs inclinados em relação aos geradores síncronos convencionais / Synchronous machines of permanent magnets present the advantage of no power consumption for the creation of the magnetic field in the rotor. The specific purpose of this thesis is the project, its construction and the evaluation of a multi-pole of concentrated coils with permanent magnets inserted in the rotor by two different geometrical forms: aligned and skewed magnets. The vindications for this study were the possibility of eliminating both the mechanical speed reducers and the excitation energy systems in electrical powerplants. The project used a three-phase induction motor (squirrel cage rotor type) of 250W and 12 poles. Starting from the original stator constructive data, we proceeded the calculi of the magnetic flux density to determine the remanent flux of the neodymium permanent magnets. In the development of the work, a new simple and modular rotor was constructed. Subsequently, the machine was evaluated in a laboratory with the purpose of checking the quantity and quality of energy produced operating as a generator. The results obtained in the evaluation of the motor operating as a generator equipped with aligned magnets were 16% of total harmonic distortion (THD), with a generating capacity of 475W at 221V – 60 Hz, though with an adverse aspect of needing a high inertial torque (cogging torque). The machine working with skewed magnets produced 7 and 8% of total harmonic distortion (THD), with a generating capacity of 236W at 195V – 60 Hz and a low cogging torque. This work demonstrated that the modular skewed magnet is an option of electrical machines presenting satisfactory performance as a generator with a reasonable quality in the context of small distributed power generation. Besides the technical conditions, it should also be considered the low cost and reduced maintenance of skewed magnets in relation to the conventional synchronous generators