15,376 research outputs found

    Computational medical imaging for total knee arthroplasty using visualitzation toolkit

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    This project is presented as a Master Thesis in the field of Civil Engineering, Biomedical specialization. As the project of an Erasmus exchange student, this thesis has been under supervision both the Universite Livre de Bruxelles and the Universitat Politecnica de Catalunya. The purpose of this thesis to put in practice all the knowledges acquired during this Master in Industrial Engineering in UPC and to be a support for medical staff in total knee arthoplasty procedures. Prof. Emmanuel Thienpont has been working for years as orthopaedic surgeon at the Hospital Sant Luc, Brussels. His years of work and research have been mainly focused on Total Knee Arthroplasty or TKA. During one of the most important steps of this procedure, the orthopaedic surgeon has to cut the head of the femur following two perpendicular cutting planes. Nevertheless, the orientation of these planes are directly dependant of the femur constitution. This Master Thesis has been conceived in order to offer the surgeon a tool to determine the proper direction planes in a previous step before the surgical procedure. This project pretends to give the surgeon an openfree computational platform to access to patient geometrical and physiological information before involving the subject in any invasive procedure

    An evolutionary behavioral model for decision making

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    For autonomous agents the problem of deciding what to do next becomes increasingly complex when acting in unpredictable and dynamic environments pursuing multiple and possibly conflicting goals. One of the most relevant behavior-based model that tries to deal with this problem is the one proposed by Maes, the Bbehavior Network model. This model proposes a set of behaviors as purposive perception-action units which are linked in a nonhierarchical network, and whose behavior selection process is orchestrated by spreading activation dynamics. In spite of being an adaptive model (in the sense of self-regulating its own behavior selection process), and despite the fact that several extensions have been proposed in order to improve the original model adaptability, there is not a robust model yet that can self-modify adaptively both the topological structure and the functional purpose\ud of the network as a result of the interaction between the agent and its environment. Thus, this work proffers an innovative hybrid model driven by gene expression programming, which makes two main contributions: (1) given an initial set of meaningless and unconnected units, the evolutionary mechanism is able to build well-defined and robust behavior networks which are adapted and specialized to concrete internal agent's needs and goals; and (2)\ud the same evolutionary mechanism is able to assemble quite\ud complex structures such as deliberative plans (which operate in the long-term) and problem-solving strategies

    Personal aircraft: a more affordable luxury

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    Access to luxury products has been limited traditionally to the upper classes. Products and services related to the means of transport have usually been considered of luxury and industrialization has made accessible to much of the population in developed countries. An emerging market is personal aircraft which is currently restricted to certain layers of society but it is expected that their use will represent the next great advance in transport. This article has the object of presenting the results of ongoing research and it focuses on possible demand and the tendency to use this transport option in Spanish societ

    That-clauses: Retention and Omission of Complementizer that in some Varieties of English

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    An OBJECT CLAUSE, also sporadically referred to as a COMMENT CLAUSE (Warner 1982: 169; Huddleston & Pullum 2002: 951), is that kind of clause functioning as the direct object of the matrix verb. In English, the most common type of object clause is introduced by the complementizer that, hence its traditional label that-clause (Quirk et al. 1985: 1049). Regarding its different usages when occurring in post-predicate position, these constructions are employed to report the speech (i.e. He said that nine indictments have been returned publicly in such investigations), thoughts (i.e. I think Stuart’s gone a bit mad) or attitudes (i.e. I was quite confident that it would stay in very well), among others (Biber et al. 1999: 660-661). As observed, the complementizer that can either be retained or omitted with no meaning alteration and Biber et al. (1999: 681-682) enumerated a series of discourse factors favouring that omission (the presence of co-referential subjects in the main clause and the that-clause, among others) and favouring that retention (the use of coordinated that-clauses, among others). Even though the topic has been extensively researched in British and American English (Biber 1999) and the history of English (Fanego 1990a, 1990b; Suárez-Gómez 2000; Calle- Martín and Romero-Barranco 2014), the academia is still in want of such studies in other varieties of contemporary English. This considered, the present paper will analyze that-clauses in Indian English, Hong Kong English and New Zealand English with the following objectives: 1) to analyze the distribution of that/zero in the mentioned varieties of English; 2) to assess the phenomenon in terms of register and the informants’ age and gender; 3) to classify the instances regarding the verb taking the that-clause (i.e. mental verbs, speech act verbs and other communication verbs); and 4) to evaluate the contribution of some factors favouring the omission and the retention of complementizer that in these environments. The source of evidence comes from the New Zealand, Indian and Hong Kong components of the International Corpus of English.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    ‘I got into the room by means of a picklock key and found him’ Complex Prepositions in Early Modern English

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    English complex prepositions can be subdivided into two-word and three-word sequences, the former containing an adverb, adjective or conjunction together with a simple preposition (i.e. instead ADV of PREP ); and the latter being composed of a preposition + noun + preposition (i.e. by PREP means NOUN of PREP ) (Quirk et al. 1985: 669-670). The complex prepositions BY WAY OF and BY MEANS OF are the result of a process of grammaticalization in which they lost part of their lexical functions and later were reanalysed as functional elements expressing instrumentality (Hoffman 2005: 71-76). From an etymological point of view, these words have different backgrounds. The word WAY, on the one hand, can be traced back to the Old English period (c. 950), with the meaning of ‘road, path’ (OED). MEAN, on the other, is a French borrowing, first attested in 1374, with the meaning of ‘an intermediary agent or instrument’ (OED). As complex prepositions in English, BY WAY OF and BY MEANS OF were first attested in 1390 and 1427, respectively (OED). The present paper has been conceived with the following objectives: 1) to assess the grammaticalization process by which nouns such as WAY and MEAN developed prepositional functions meaning instrumentality; 2) to analyse the use and distribution of BY WAY OF and BY MEANS OF in the History of English; and 3) to determine any likely preference in terms of the informants’ gender and social class. The source of evidence comes from the the Corpus of Early English Correspondence and the Old Bailey Corpus.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The single-electron transport in a three-ion magnetic molecule modulated by a transverse field

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    We study single-electron transport in a three-ion molecule with strong uniaxial anisotropy and in the presence of a transverse magnetic field. Two magnetic ions are connected to each other through a third, nonmagnetic ion. The magnetic ions are coupled to ideal metallic leads and a back gate voltage is applied to the molecule, forming a field-effect transistor. The microscopic Hamiltonian describing this system includes inter-ion hopping, on-site repulsions, and magnetic anisotropies. For a range of values of the parameters of the Hamiltonian, we obtain an energy spectrum similar to that of single-molecule magnets in the giant-spin approximation where the two states with maximum spin projection along the uniaxial anisotropy axis are well separated from other states. In addition, upon applying an external in-plane magnetic field, the energy gap between the ground and first excited states of the molecule oscillates, going to zero at certain special values of the field, in analogy to the diabolical points resulting from Berry phase interference in the giant spin model. Thus, our microscopic model provides the same phenomenological behavior expected from the giant spin model of a single-molecule magnet but with direct access to the internal structure of the molecule, thus making it more appropriate for realistic electronic transport studies. To illustrate this point, the nonlinear electronic transport in the sequential tunneling regime is evaluated for values of the field near these degeneracy points. We show that the existence of these points has a clear signature in the I-V characteristics of the molecule, most notably the modulation of excitation lines in the differential conductance.Comment: 10 pages, 13 figure

    On human motion prediction using recurrent neural networks

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    Human motion modelling is a classical problem at the intersection of graphics and computer vision, with applications spanning human-computer interaction, motion synthesis, and motion prediction for virtual and augmented reality. Following the success of deep learning methods in several computer vision tasks, recent work has focused on using deep recurrent neural networks (RNNs) to model human motion, with the goal of learning time-dependent representations that perform tasks such as short-term motion prediction and long-term human motion synthesis. We examine recent work, with a focus on the evaluation methodologies commonly used in the literature, and show that, surprisingly, state-of-the-art performance can be achieved by a simple baseline that does not attempt to model motion at all. We investigate this result, and analyze recent RNN methods by looking at the architectures, loss functions, and training procedures used in state-of-the-art approaches. We propose three changes to the standard RNN models typically used for human motion, which result in a simple and scalable RNN architecture that obtains state-of-the-art performance on human motion prediction.Comment: Accepted at CVPR 1

    Asymptotically Exact Approximations for the Symmetric Difference of Generalized Marcum-Q Functions

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    (c) 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. DOI: 10.1109/TVT.2014.2337263In this paper, we derive two simple and asymptotically exact approximations for the function defined as ΔQm(a, b) =Δ Qm(a, b) - Qm(b, a). The generalized Marcum Q-function Qm(a, b) appears in many scenarios in communications in this particular form and is referred to as the symmetric difference of generalized Marcum Q-functions or the difference of generalized Marcum Q-functions with reversed arguments. We show that the symmetric difference of Marcum Q-functions can be expressed in terms of a single Gaussian Q-function for large and even moderate values of the arguments a and b. A second approximation for ΔQm(a, b) is also given in terms of the exponential function. We illustrate the applicability of these new approximations in different scenarios: 1) statistical characterization of Hoyt fading; 2) performance analysis of communication systems; 3) level crossing statistics of a sampled Rayleigh envelope; and 4) asymptotic approximation of the Rice Ie-function.Universidad de Málaga. Campus de Excelencia Internacional. Andalucía Tech

    Firm Size and Regional Linkages. A Typology of Manufacturing Establishments in Southern Spain

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    Regions with different levels of development are characterized by different enterprise compositions according to firm size and regional productive linkages. Using these two variables and two additional ones -the technological level and the position in the value chain-, the composition of the industrial sector in any region can be studied. In this respect, a new theoretical enterprise typology is proposed in this paper as a powerful analytical tool. Furthermore, an empirical work is carried out using a data set from the survey done to estimate the regional input-output table of Andalusia, a backward region in southern Spain. Thus, the theoretical enterprise typology is applied to the industry in Andalusia, so that some strengths and weaknesses of the regional economy are identified
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