Multi-criteria optimization manipulator trajectory planning

In the last twenty years genetic algorithms (GAs) were applied in a plethora of fields such as: control, system identification, robotics, planning and scheduling, image processing, and pattern and speech recognition (Bäck et al., 1997). In robotics the problems of trajectory planning, collision avoidance and manipulator structure design considering a single criteria has been solved using several techniques (Alander, 2003). Most engineering applications require the optimization of several criteria simultaneously. Often the problems are complex, include discrete and continuous variables and there is no prior knowledge about the search space. These kind of problems are very more complex, since they consider multiple design criteria simultaneously within the optimization procedure. This is known as a multi-criteria (or multiobjective) optimization, that has been addressed successfully through GAs (Deb, 2001). The overall aim of multi-criteria evolutionary algorithms is to achieve a set of non-dominated optimal solutions known as Pareto front. At the end of the optimization procedure, instead of a single optimal (or near optimal) solution, the decision maker can select a solution from the Pareto front. Some of the key issues in multi-criteria GAs are: i) the number of objectives, ii) to obtain a Pareto front as wide as possible and iii) to achieve a Pareto front uniformly spread. Indeed, multi-objective techniques using GAs have been increasing in relevance as a research area. In 1989, Goldberg suggested the use of a GA to solve multi-objective problems and since then other researchers have been developing new methods, such as the multi-objective genetic algorithm (MOGA) (Fonseca & Fleming, 1995), the non-dominated sorted genetic algorithm (NSGA) (Deb, 2001), and the niched Pareto genetic algorithm (NPGA) (Horn et al., 1994), among several other variants (Coello, 1998). In this work the trajectory planning problem considers: i) robots with 2 and 3 degrees of freedom (dof ), ii) the inclusion of obstacles in the workspace and iii) up to five criteria that are used to qualify the evolving trajectory, namely the: joint traveling distance, joint velocity, end effector / Cartesian distance, end effector / Cartesian velocity and energy involved. These criteria are used to minimize the joint and end effector traveled distance, trajectory ripple and energy required by the manipulator to reach at destination point. Bearing this ideas in mind, the paper addresses the planning of robot trajectories, meaning the development of an algorithm to find a continuous motion that takes the manipulator from a given starting configuration up to a desired end position without colliding with any obstacle in the workspace. The chapter is organized as follows. Section 2 describes the trajectory planning and several approaches proposed in the literature. Section 3 formulates the problem, namely the representation adopted to solve the trajectory planning and the objectives considered in the optimization. Section 4 studies the algorithm convergence. Section 5 studies a 2R manipulator (i.e., a robot with two rotational joints/links) when the optimization trajectory considers two and five objectives. Sections 6 and 7 show the results for the 3R redundant manipulator with five goals and for other complementary experiments are described, respectively. Finally, section 8 draws the main conclusions.

Evolutionary trajectory optimization for redundant robots

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms have been investigated in the last years. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms. In this case the trajectory planning is formulated as an optimization problem with constraints.

Complex dynamics in the trajectory control of redundant manipulators

Redundant manipulators allow the trajectory optimization, the obstacle avoidance, and the resolution of singularities. For this type of manipulators, the kinematic control algorithms adopt generalized inverse matrices that may lead to unpredictable responses. Motivated by these problems this paper studies the complexity revealed by the trajectory planning scheme when controlling redundant manipulators. The results reveal fundamental properties of the chaotic phenomena and give a deeper insight towards the development of superior trajectory control algorithms.

Trajectory planning of redundant manipulators using genetic algorithms

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms. The results are compared with a genetic algorithm that adopts the direct kinematics. In both cases the trajectory planning is formulated as an optimization problem with constraints.

Fractional dynamics in the trajectory control of redundant manipulators

Under the pseudoinverse control, robots with kinematical redundancy exhibit an undesirable chaotic joint motion which leads to an erratic behavior. This paper studies the complexity of fractional dynamics of the chaotic response. Fourier and wavelet analysis provides a deeper insight, helpful to know better the lack of repeatability problem of redundant manipulators. This perspective for the study of the chaotic phenomena will permit the development of superior trajectory control algorithms.

Manipulator trajectory planning using a MOEA

Generating manipulator trajectories considering multiple objectives and obstacle avoidance is a non-trivial optimization problem. In this paper a multi-objective genetic algorithm based technique is proposed to address this problem. Multiple criteria are optimized considering up to five simultaneous objectives. Simulation results are presented for robots with two and three degrees of freedom, considering two and five objectives optimization. A subsequent analysis of the spread and solutions distribution along the converged non-dominated Pareto front is carried out, in terms of the achieved diversity.

Optimal brake specific fuel consumption trajectory for stand-alone variable speed Diesel Gen-Set

Energy efficiency plays an important role to the CO2 emissions reduction, combating climate change and improving the competitiveness of the economy. The problem presented here is related to the use of stand-alone diesel gen-sets and its high specific fuel consumptions when operates at low loads. The variable speed gen-set concept is explained as an energy-saving solution to improve this system efficiency. This paper details how an optimum fuel consumption trajectory based on experimentally Diesel engine power map is obtained.

Resource Scheduling in Residential Microgrids Considering Energy Selling to External Players

The operation of distribution networks has been facing changes with the implementation of smart grids and microgrids, and the increasing use of distributed generation. The specific case of distribution networks that accommodate residential buildings, small commerce, and distributed generation as the case of storage and PV generation lead to the concept of microgrids, in the cases that the network is able to operate in islanding mode. The microgrid operator in this context is able to manage the consumption and generation resources, also including demand response programs, obtaining profits from selling electricity to the main network. The present paper proposes a methodology for the energy resource scheduling considering power flow issues and the energy buying and selling from/to the main network in each bus of the microgrid. The case study uses a real distribution network with 25 bus, residential and commercial consumers, PV generation, and storage.

Chaos Dynamics in the Trajectory Conjtrol of Redundant Manipulators

Nonlinear Dynamics, chaos, Control, and Their Applications to Engineering Sciences: Vol. 6 - Applications of nonlinear phenomena

Chaotic Phenomena and Performance Optimization in the Trajectory Control of Redundant Manipulators

Redundant manipulators have some advantages when compared with classical arms because they allow the trajectory optimization, both on the free space and on the presence of abstacles, and the resolution of singularities. For this type of manipulators, several kinetic algorithms adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through several experiments that reveal the difficulties that often arise. Motivated by theseproblems this paper presents a new method that ptimizes the manipulability through a least squre polynomialapproximation to determine the joints positions. Moreover, the article studies influence on the dynamics, when controlling redundant and hyper-redundant manipulators. The experiment confirm the superior performance of the proposed algorithm for redundant and hyper-redundant manipulators, revealing several fundamental properties of the chaotic phenomena, and gives a deeper insight towards the future development of superior trajectory control algorithms.

FIRST REPORT ON Cryptococcus neoformans IN PIGEON EXCRETA FROM PUBLIC AND RESIDENTIAL LOCATIONS IN THE METROPOLITAN AREA OF CUIABÁ, STATE OF MATO GROSSO, BRAZIL

SUMMARYCryptococcosis is a severe systemic mycosis caused by two species of Cryptococcus that affect humans and animals: C. neoformans and C. gattii. Cosmopolitan and emergent, the mycosis results from the interaction between a susceptible host and the environment. The occurrence of C. neoformanswas evaluated in 122 samples of dried pigeon excreta collected in 49 locations in the City of Cuiabá, State of Mato Grosso, Brazil, including public squares (n = 5), churches (n = 4), educational institutions (n = 3), health units (n = 8), open areas covered with asbestos (n = 4), residences (n = 23), factory (n = 1) and a prison (n = 1). Samples collected from July to December of 2010 were seeded on Niger seed agar (NSA). Dark brown colonies were identified by urease test, carbon source assimilation tests and canavanine-glycine-bromothymol blue medium. Polymerase chain reaction primer pairs specific for C. neoformans were also used for identification. Cryptococcus neoformans associated to pigeon excreta was isolated from eight (6.6%) samples corresponding to six (12.2%) locations.Cryptococcus neoformans was isolated from urban areas, predominantly in residences, constituting a risk of acquiring the disease by immunocompromised and immunocompetent individuals.

Analysing and visualising areal crime data. A case study of residential burglary in San Francisco, USA

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Assessing the community needs of mental health residential care service users in Republic of Moldova

RESUMO: Background: Problemas de saúde mental são um grande problema clínico e social na República da Moldávia, representando uma quota significante de deficiência, sendo classificada no top cinco das dez linhas na hierarquia das condições. A taxa de incidência tem sido crescente na República da Moldávia, atingindo cerca de 15.000 por ano (14,655 em 2011), ou seja, 411,4 por 100 mil habitantes, e uma taxa de prevalência de 97.525 pessoas em 2011, ou seja, 2,737.9 por 100 mil habitantes. Sistema de atendimento psiquiátrico fornece serviços de saúde mental escassos a nível da comunidade, visando principalmente terapia hospitalar, centralizada, através de uma rede de três hospitais psiquiátricos, com 1.860 camas e 4 sanatórios psico- neurológicos com 1890 camas, assim alimentando-se a estigmatização do paciente. Objetivos: O objetivo deste estudo foi a avaliação das necessidades individuais dos beneficiários e do seu nível de autonomia dentro de cuidados residenciais, para o planeamento de reformas de saúde mental e desinstitucionalização na República da Moldávia. Este estudo foi encomendado pelo Ministério do Trabalho, Proteção Social e da Família e pelo Ministério da Saúde, com o apoio da Organização Mundial da Saúde, para determinar o cumprimento eficaz do artigo 19 da Convenção da ONU. O estudo tem os seguintes objetivos: Avaliar o nível de autonomia dos residentes nos hospitais psiquiátricos e sanatórios psico-neurológico, usando uma amostra representativa de 10 por ce nto do número total de pacientes/residentes e comparação cruzada; Para avaliar quatro sanatórios psico-neurológicos para adultos e três hospitais psiquiátricos; Para desenvolver recomendações para o planeamento da desinstitucionalização das pessoas com problemas de saúde mental e colocação na comunidade com base nos resultados do estudo. Metodologia e resultados: O estudo fez uso de duas ferramentas globais: questionário para a avaliação individual dos residentes do estabelecimento de saúde mental, e questionário de avaliação institucional. Todos os entrevistados foram divididos em quatro categorias conforme com o grau de dependência e preparação de viver de forma independente na comunidade. Apenas 1,2% dos entrevistados de PNHB eram totalmente dependentes de terceiros ou serviços especializados, tornando-se a categoria 4, que necessitam de cuidados e apoio contínuo. No PH esta categoria de pessoas é ausente. Conclusões: A condição dos entrevistados foi pior em PNBH que em PH. No entanto, ainda, aqueles que estão prontos para ser desinstitucionalizados correspondem com a maior parte dos entrevistados. Todos os hospitais tinham o consentimento do utente para admissão e tratamento, enquanto não houve consentimento qualquer em PNBH. É bastante óbvio que tanto os hospitais como também a sistema de assistência residencial não atingem a sua finalidade, o que significa que a maioria dos utentes pode ser desinstitucionalizados, sem qualquer terapia de suporte.------------------ABSTRACT: Background: Mental health problems are a major clinical and social issue in the Republic of Moldova,accounting for a significant share of disability and ranking in top five of the ten lines in the hierarchy of conditions. The incidence rate has been growing in the Republic of Moldova to reach approximately 15 thousand a year (14,655 in 2011), i.e. 411.4 per 100 thousand population, and a prevalence rate of 97,525 thousand people in 2011, i.e. 2,737.9 per 100 thousand population. Psychiatric care system provides for scanty mental health services at community level, aiming mainly at centralized hospital-based therapy through a network of three psychiatric hospitals tallying up 1,860 beds and 4 psycho-neurological boarding houses with 1,890 beds, thus fuelling up patient stigmatization. Objectives: The purpose of this study was to assess the individual needs of beneficiaries and their level of autonomy within residential care for the planning of mental health system reforms and deinstitutionalization in the Republic of Moldova. This study was commissioned by the Ministry of Labour, Social Protection and Family and by the Ministry of Health, with the World Health Organization support, to provide for effective enforcement of article 19 of the UN CRPD. The study pursued the following goals: To evaluate the level of autonomy of the psychiatric hospital and psycho-neurological boarding house residents by using a representative sample of 10 per cent of the total number of patients / residents and cross-comparison; To evaluate four psycho-neurological boarding houses for adults and three psychiatric hospitals; To develop recommendations for planning the deinstitutionalization of people with mental health problems and community placement based on the study findings.Methodology and results: The study made use of two global tools: questionnaire for individual assessment of mental health facility residents, and institutional assessment questionnaire. All interviewees were divided into four categories by one’s degree of dependence and readiness to live independently in the community. Only 1.2% of respondents from PNHB were fully dependent on a third party or specialized services, making up category 4, requiring continuous care and support. In PH this category of people is absent.Conclusions: The condition of respondents was worse in PNBH than in PH. However, yet, those ready to be deinstitutionalized accounted for most of respondents there. All hospitals had the resident’s consent to admission and treatment, whereas there was no consent in PNBH whatsoever. It is quite obvious that both the hospitals and residential care system do not achieve their intended purpose, meaning that the majority of residents may be deinstitutionalized without any support therapy.

The effects of cultural heritage on residential property values: Evidence from Lisbon, Portugal

This paper examines the impact of historic amenities on residential housing prices in the city of Lisbon, Portugal. Our study is directed towards identifying the spatial variation of amenity values for churches, palaces, lithic (stone) architecture and other historic amenities via the housing market, making use of both global and local spatial hedonic models. Our empirical evidence reveals that different types of historic and landmark amenities provide different housing premiums. While having a local non-landmark church within 100 meters increases housing prices by approximately 4.2%, higher concentrations of non-landmark churches within 1000 meters yield negative effects in the order of 0.1% of prices with landmark churches having a greater negative impact around 3.4%. In contrast, higher concentration of both landmark and non-landmark lithic structures positively influence housing prices in the order of 2.9% and 0.7% respectively. Global estimates indicate a negative effect of protected zones, however this significance is lost when accounting for heterogeneity within these areas. We see that the designation of historic zones may counteract negative effects on property values of nearby neglected buildings in historic neighborhoods by setting additional regulations ensuring that dilapidated buildings do not damage the city’s beauty or erode its historic heritage. Further, our results from a geographically weighted regression specification indicate the presence of spatial non-stationarity in the effects of different historic amenities across the city of Lisbon with variation between historic and more modern areas.

Analysis of portuguese residential buildings’ needs and proposed solutions

The Portuguese housing sector experienced a significant growth throughout the 20th century, particularly in the last quarter, after the democratic revolution in 1974. In fact, the number of buildings built between 1970 and 1990 is more than one third of the buildings actually existing in Portugal. Therefore most of them were built before the publication of the first regulation concerning the energy efficiency in buildings. Regarding this scenario, it would be expected that rehabilitation activities would represent most of the current construction activities. However, given some remaining barriers from old social policies, this situation is not observed; actually building retrofitting is the least significant sector, accentuating the degradation level of major part of the Portuguese housing stock. Several studies show that the main problems are found in the buildings envelope elements, such as roofs and façades. Based on this context, the aim of this paper is to introduce some examples of building retrofitting systems that, adapted to the Portuguese main needs and requirements may represent sustainable solutions to overcome the identified needs of Portuguese buildings' envelope.