931 resultados para many-objective problems


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Object recognition has long been a core problem in computer vision. To improve object spatial support and speed up object localization for object recognition, generating high-quality category-independent object proposals as the input for object recognition system has drawn attention recently. Given an image, we generate a limited number of high-quality and category-independent object proposals in advance and used as inputs for many computer vision tasks. We present an efficient dictionary-based model for image classification task. We further extend the work to a discriminative dictionary learning method for tensor sparse coding. In the first part, a multi-scale greedy-based object proposal generation approach is presented. Based on the multi-scale nature of objects in images, our approach is built on top of a hierarchical segmentation. We first identify the representative and diverse exemplar clusters within each scale. Object proposals are obtained by selecting a subset from the multi-scale segment pool via maximizing a submodular objective function, which consists of a weighted coverage term, a single-scale diversity term and a multi-scale reward term. The weighted coverage term forces the selected set of object proposals to be representative and compact; the single-scale diversity term encourages choosing segments from different exemplar clusters so that they will cover as many object patterns as possible; the multi-scale reward term encourages the selected proposals to be discriminative and selected from multiple layers generated by the hierarchical image segmentation. The experimental results on the Berkeley Segmentation Dataset and PASCAL VOC2012 segmentation dataset demonstrate the accuracy and efficiency of our object proposal model. Additionally, we validate our object proposals in simultaneous segmentation and detection and outperform the state-of-art performance. To classify the object in the image, we design a discriminative, structural low-rank framework for image classification. We use a supervised learning method to construct a discriminative and reconstructive dictionary. By introducing an ideal regularization term, we perform low-rank matrix recovery for contaminated training data from all categories simultaneously without losing structural information. A discriminative low-rank representation for images with respect to the constructed dictionary is obtained. With semantic structure information and strong identification capability, this representation is good for classification tasks even using a simple linear multi-classifier.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In the standard Vehicle Routing Problem (VRP), we route a fleet of vehicles to deliver the demands of all customers such that the total distance traveled by the fleet is minimized. In this dissertation, we study variants of the VRP that minimize the completion time, i.e., we minimize the distance of the longest route. We call it the min-max objective function. In applications such as disaster relief efforts and military operations, the objective is often to finish the delivery or the task as soon as possible, not to plan routes with the minimum total distance. Even in commercial package delivery nowadays, companies are investing in new technologies to speed up delivery instead of focusing merely on the min-sum objective. In this dissertation, we compare the min-max and the standard (min-sum) objective functions in a worst-case analysis to show that the optimal solution with respect to one objective function can be very poor with respect to the other. The results motivate the design of algorithms specifically for the min-max objective. We study variants of min-max VRPs including one problem from the literature (the min-max Multi-Depot VRP) and two new problems (the min-max Split Delivery Multi-Depot VRP with Minimum Service Requirement and the min-max Close-Enough VRP). We develop heuristics to solve these three problems. We compare the results produced by our heuristics to the best-known solutions in the literature and find that our algorithms are effective. In the case where benchmark instances are not available, we generate instances whose near-optimal solutions can be estimated based on geometry. We formulate the Vehicle Routing Problem with Drones and carry out a theoretical analysis to show the maximum benefit from using drones in addition to trucks to reduce delivery time. The speed-up ratio depends on the number of drones loaded onto one truck and the speed of the drone relative to the speed of the truck.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In elections, majority divisions pave the way to focal manipulations and coordination failures, which can lead to the victory of the wrong candidate. This paper shows how this flaw can be addressed if voter preferences over candidates are sensitive to information. We consider two potential sources of divisions: majority voters may have similar preferences but opposite information about the candidates, or opposite preferences. We show that when information is the source of majority divisions, Approval Voting features a unique equilibrium with full information and coordination equivalence. That is, it produces the same outcome as if both information and coordination problems could be resolved. Other electoral systems, such as Plurality and Two-Round elections, do not satisfy this equivalence. The second source of division is opposite preferences. Whenever the fraction of voters with such preferences is not too large, Approval Voting still satisfies full information and coordination equivalence.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Sociais, Departamento de Sociologia, 2016.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Ligand-protein docking is an optimization problem based on predicting the position of a ligand with the lowest binding energy in the active site of the receptor. Molecular docking problems are traditionally tackled with single-objective, as well as with multi-objective approaches, to minimize the binding energy. In this paper, we propose a novel multi-objective formulation that considers: the Root Mean Square Deviation (RMSD) difference in the coordinates of ligands and the binding (intermolecular) energy, as two objectives to evaluate the quality of the ligand-protein interactions. To determine the kind of Pareto front approximations that can be obtained, we have selected a set of representative multi-objective algorithms such as NSGA-II, SMPSO, GDE3, and MOEA/D. Their performances have been assessed by applying two main quality indicators intended to measure convergence and diversity of the fronts. In addition, a comparison with LGA, a reference single-objective evolutionary algorithm for molecular docking (AutoDock) is carried out. In general, SMPSO shows the best overall results in terms of energy and RMSD (value lower than 2A for successful docking results). This new multi-objective approach shows an improvement over the ligand-protein docking predictions that could be promising in in silico docking studies to select new anticancer compounds for therapeutic targets that are multidrug resistant.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertação para obtenção do grau de Mestre em Design da Comunicação, apresentada na Universidade de Lisboa - Faculdade de Arquitetura.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertação de mest. Ciências Económicas e Empresariais, Faculdade de Economia, Univ. do Algarve, Instituto Superior de Economia e Gestão, Univ. Técnica de Lisboa, 2007

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A preocupação com a qualidade dos serviços prestados pelas organizações de saúde é uma realidade. Em resultado de várias pressões e diferentes metodologias têm sido implementadas nas instituições Sistemas de Informação a fim de melhorar a qualidade e segurança dos procedimentos aí desenvolvidos. A qualidade dos Sistemas de Informação assume um destaque pela sua componente de mais-valia, neste trabalho procuramos avalia-la e verificar a sua correta implementação. A presente dissertação reporta-se ao estudo dos Sistemas de informação no Serviço de Radiologia do HCC, tendo como objetivo principal saber se os Sistemas de Informação, potenciaram a melhoria da qualidade de desempenho dos profissionais de saúde, assim como caracterizar a qualidade dos Sistemas de Informação. Como estratégia de pesquisa optamos por um estudo de natureza descritiva, utilizando um modelo de análise quantitativo. Aplicou-se um questionário elaborado pela investigadora, tendo sido aceites as respostas de 55 questionários realizados aos utilizadores dos SI. De uma forma geral os resultados demonstram que os Sistemas de Informação foram bem aceites por parte dos profissionais deste serviço, existindo porem algumas deficiências que não permite que se atinja níveis de qualidade elevados. Relativamente à formação depreendemos que existem algumas lacunas relativas ao processo de formação dos utilizadores, que podem ser colmatadas por uma intervenção adequada. ABSTRACT: The concern about the quality of the accounted services by the health organizations is a reality. Information Systems have been installed in many establishments as a result of many pressures and different methodologies in order to improve the quality and safety of the procedures developed in such places. The quality of the Information Systems gains relevance due to its “rise” character; on this essay we aimed to evaluate and verify its adequate execution. The present essay is about the study of the Information Systems on the Radiology Service of Hospital Curry Cabral (HCC) being its main objective to know if the Information Systems improved the performance of the health professionals, as well as to point out their quality. We decided to build a study of descriptive nature using a quantitative analysis method. We applied an inquiry elaborated by the researcher and accepted the answers of 55 inquiries made to the SI users. In general, the results revealed that the Information Systems were well accepted by the professionals of this service. However, some minor problems do not allow high standard of quality to be obtained. As regards training we understand that there are a few defaults concerning the process of formation of the users which can be surpassed if using an adequate intervention.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

No mundo do trabalho, o êxito depende da capacidade revelada para conhecer e desempenhar o nosso papel. E a carreira docente não foge a esta regra. À semelhança do que acontece com os actores e as actrizes - que são avaliados pela qualidade que imprimem aos papéis representados - também os juízos de valor sobre os docentes assentam na aptidão demonstrada para dominarem todas as subtilezas inerentes ao papel de professores. A sua forma de actuar perante situações melindrosas e excepcionais, de indisciplina e de violência, o seu sentir, constituirão o objecto de análise neste trabalho. Os professores, muitas vezes, actuam com base em conceitos veiculados pelos seus pais e formadores, que poderão ter sido válidos para eles, mas que não o são, decerto, hoje em dia. Podem ter resultado no início das carreiras, mas, em regra, foram perdendo utilidade em fases posteriores. Pela análise das histórias de vida dos professores levantam-se várias hipóteses quanto à construção dessas posturas e aos condimentos que possibilitam uma adesão à mudança necessária. Urge implementar uma alteração da sua maneira de pensar a abordagem às situações de indisciplina e de violência escolares, porque tal é essencial para alterar comportamentos que lhes podem ser prejudiciais. Este trabalho obedeceu a dois propósitos: proporcionar informação enquadrada em bases teóricas sólidas que possa sustentar intervenções ajustadas na sala de aula e suscitar a reflexão dos docentes sobre os seus papéis e as suas práticas. Não temos, contudo, a pretensão de que essa informação seja bastante para a resolução dos problemas de indisciplina, mas alimentamos a esperança de que as pistas de reflexão e de acção, bem como os conceitos mobilizados, possam ajudar a uma acção educativa simultaneamente mais eficaz e satisfatória. Assim, acreditamos que este trabalho estimulará os professores a encarar as situações de indisciplina e violência de um modo mais tranquilo, emocionalmente mais distante, sem o rígido recurso à auto culpabilização ou às hetero-acusações. ABSTRACT: ln the working world, success depends on the way we know and play our roles. And the teaching role is not different. An actor (or actress) is evaluated by the quality of his (or her) role performance; in the same way, the value judgements about teachers are linked with their capacity to dominate all the aspects of their teaching role. Their way to intervene in problematic and special situations, dealing with violence and indiscipline, their feelings, are the main objective of this research project. Many times, teachers act remembering what their parents and old teachers taught them. These old concepts and ideas worked well in the beginning of their careers but are not valid today. Analyzing the life stories of teachers, we can find several answers for their positions when facing these problems. It is necessary to compel them to change their minds, to transform their reactions over problematic situations of indiscipline and violence or they will face more problems in the near future. This research project has two intentions: to give theoretical information helping teachers to act correctly in the classrooms and to show that a time for reflection is necessary, to analyse their roles and procedures. We are not so naïve in thinking that this project is enough to find a solution for all the indiscipline and violence problems in schools, but we really believe that it will help teachers to face those problems in a more peaceful way, not so emotional and with better results.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Natural stone has been a popular and reliable building material throughout history appearing in many historic monuments and in more recent buildings. Research into the intrinsic properties of specific stones is important because it gives us a greater understanding of the factors that limit and act on them. This can help prevent serious problems from occurring in our buildings bringing both esthetic benefits and financial savings. To this end, the main objective of this research has been to study the influence of the fabric and the mineral composition of two types of sandstone on their durability. The first is a red continental sandstone from the Buntsandstein Age called “Molinaza Roja”, which is quarried in Montoro (Cordoba). The second is quarried in Ronda (Malaga) and is sold under the trade name of “Arenisca Ronda”. It is a light pink-whitish calcarenite deposited during the Late Tortonian to Late Messinian. We characterized their petrological and petrophysical properties by studying their rock fabrics, porous systems and mechanical properties. In order to obtain a complete vision of the behavior of their rock fabrics, we also carried out two decay tests, the salt crystallization and the freeze–thaw tests. We then measured the effects on the textures of the altered samples during and after the decay tests and we evaluated the changes in the porous system. By comparing the results between intact and altered samples, we found that Arenisca Ronda is less durable because it has a high quantity of expandable clays (smectites) and a high percentage of pores in the 0.1–1 μm range, in which the pressure produced by salt crystallization is strongest. In Molinaza Roja the decay agents caused significant sanding due to loss of cohesion between the clasts, especially during the salt crystallization test. In both stones, the anisotropies (oriented textures) have an important role in their hydric and dynamic behavior and also affect their mechanical properties (especially in the compression resistance). No changes in color were detected.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: Complex chronic diseases are a challenge for the current configuration of Health services. Case management is a service frequently provided for people with chronic conditions and despite its effectiveness in many outcomes, such as mortality or readmissions, uncertainty remains about the most effective form of team organization, structures, and the nature of the interventions. Many processes and outcomes of case management for people with complex chronic conditions cannot be addressed with the information provided by electronic clinical records. Registries are frequently used to deal with this weakness. The aim of this study was to generate a registry-based information system of patients receiving case management to identify their clinical characteristics, their context of care, events identified during their follow-up, interventions developed by case managers, and services used. Methods and design: The study was divided into three phases, covering the detection of information needs, the design and its implementation in the healthcare system, using literature review and expert consensus methods to select variables that would be included in the registry. Objective: To describe the essential characteristics of the provision of ca re lo people who receive case management (structure, process and outcomes), with special emphasis on those with complex chronic diseases. Study population: Patients from any District of Primary Care, who initiate the utilization of case management services, to avoid information bias that may occur when including subjects who have already been received the service, and whose outcomes and characteristics could not be properly collected. Results: A total of 102 variables representing structure, processes and outcomes of case management were selected for their inclusion in the registry after the consensus phase. Total sample was composed of 427 patients, of which 211 (49.4%) were women and 216 (50.6%) were men. The average functional level (Barthel lndex) was 36.18 (SD 29.02), cognitive function (Pfeiffer) showed an average of 4.37 {SD 6.57), Chat1son Comorbidity lndex, obtained a mean of 3.03 (SD 2.7) and Social Support (Duke lndex) was 34.2 % (SD 17.57). More than half of patients include in the Registry, correspond lo immobilized or transitional care for patients discharged from hospital (66.5 %). The patient's educational level was low or very low (50.4%). Caregivers overstrain (Caregiver stress index), obtained an average value of 6.09% (SD 3.53). Only 1.2 % of patients had declared their advanced directives, 58.6 had not defined the tutelage and the vast majority lived at home 98.8 %. Regarding the major events recorded at RANGE Registry, 25.8 % of the selected patients died in the first three months, 8.2 % suffered a hospital admission at least once time, 2.3%, two times, and 1.2% three times, 7.5% suffered a fall, 8.7% had pressure ulcer, 4.7% had problems with medication, and 3.3 % were institutionalized. Stroke is the more prevalent health problem recorded (25.1%), followed by hypertension (11.1%) and COPD (11.1%). Patients registered by NCMs had as main processes diabetes (16.8%) and dementia (11.3 %). The most frequent nursing diagnoses referred to the self-care deficit in various activities of daily living. Regarding to nursing interventions, described by the Nursing Intervention Classification (NIC), dementia management is the most used intervention, followed by mutual goal setting, caregiver and emotional support. Conclusions: The patient profile who receive case management services is a chronic complex patient with severe dependence, cognitive impairment, normal social support, low educational level, health problems such as stroke, hypertension or COPD, diabetes or dementia, and has an informal caregiver. At the first follow up, mortality was 19.2%, and a discrete rate of readmissions and falls.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Efficient hill climbers have been recently proposed for single- and multi-objective pseudo-Boolean optimization problems. For $k$-bounded pseudo-Boolean functions where each variable appears in at most a constant number of subfunctions, it has been theoretically proven that the neighborhood of a solution can be explored in constant time. These hill climbers, combined with a high-level exploration strategy, have shown to improve state of the art methods in experimental studies and open the door to the so-called Gray Box Optimization, where part, but not all, of the details of the objective functions are used to better explore the search space. One important limitation of all the previous proposals is that they can only be applied to unconstrained pseudo-Boolean optimization problems. In this work, we address the constrained case for multi-objective $k$-bounded pseudo-Boolean optimization problems. We find that adding constraints to the pseudo-Boolean problem has a linear computational cost in the hill climber.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Technologies for Big Data and Data Science are receiving increasing research interest nowadays. This paper introduces the prototyping architecture of a tool aimed to solve Big Data Optimization problems. Our tool combines the jMetal framework for multi-objective optimization with Apache Spark, a technology that is gaining momentum. In particular, we make use of the streaming facilities of Spark to feed an optimization problem with data from different sources. We demonstrate the use of our tool by solving a dynamic bi-objective instance of the Traveling Salesman Problem (TSP) based on near real-time traffic data from New York City, which is updated several times per minute. Our experiment shows that both jMetal and Spark can be integrated providing a software platform to deal with dynamic multi-optimization problems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Sequence problems belong to the most challenging interdisciplinary topics of the actuality. They are ubiquitous in science and daily life and occur, for example, in form of DNA sequences encoding all information of an organism, as a text (natural or formal) or in form of a computer program. Therefore, sequence problems occur in many variations in computational biology (drug development), coding theory, data compression, quantitative and computational linguistics (e.g. machine translation). In recent years appeared some proposals to formulate sequence problems like the closest string problem (CSP) and the farthest string problem (FSP) as an Integer Linear Programming Problem (ILPP). In the present talk we present a general novel approach to reduce the size of the ILPP by grouping isomorphous columns of the string matrix together. The approach is of practical use, since the solution of sequence problems is very time consuming, in particular when the sequences are long.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertação (mestrado)—Universidade de Brasília, Instituto de Letras, Departamento de Línguas Estrangeiras e Tradução, Programa de Pós-Graduação em Estudos da Tradução, 2016.