Pitfalls and guide lines in the transition to object oriented software design methodologies

A research report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering.Due to the dynamic nature of the software engineering industry there is a constant move towards new strategies for solving design problems. More specifically there is a move towards Object Oriented (OO) methodologies, presumably because of the various advantages offered in terms of maintainability, and reuse of code produced this way. As with various other aspects of the software industry there are however also problems encountered in this transition and lessons to be learned from the experience of companies who have already performed this change. This research report investigates possible guidelines for companies who are currently contemplating a change to the OO software design methodologies, by covering a collection of issues one should know about prior to this change. It also summarises the problems faced in the transition so far, the reasons for these problems and suggests possible solutions. Lastly it also investigates new trends in the OO arena. The emphasis is on South African companies and projects. The results obtained are compared with results obtained overseas to find out what the differences and similarities are. Areas of concern are also identified, where theoreticians' views have been ignored, and both South African and overeeas companies have not implemented any of the suggestions made.Andrew Chakane 201

Couples’ Attitudes, Childbirth, and the Division of Labor

In this article, the authors examine effects of partners’ attitudes on the timing of the birth of a first child, the division of domestic labor, the division of child care, and the division of paid labor of couples. They use data from the Panel Study of Social Integration in the Netherlands, which includes independent measures of both partners’ attitudes in one wave (1995) and family life behavior in the next wave (1999). Using theories about decision rules, the authors formulate hypotheses about possible outcomes when partners have dissimilar attitudes. The results show that partners’ attitudes are not always identical. Most important, attitudes of both partners are found to be equally important in joint decisions

Análise dinâmica de cristais fonônicos e metamateriais elásticos utilizando abordagens semi-analíticas e numéricas

Orientador: José Maria Campos dos SantosTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: Nesta tese, os métodos de expansão em ondas planas (PWE), expansão em ondas planas melhorado (IPWE) e expansão em ondas planas estendido (EPWE) são utilizados para obter a estrutura de banda de cristais fonônicos (PnCs) e de metamateriais elásticos (EMs) uni- (1D) e bi-dimensionais (2D), isto é, estruturas arti?ciais projetadas para criarem bandas proibidas de Bragg e/ou localmente ressonantes. Estas estruturas periódicas estão sendo aplicadas em vários ramos da ciência e possuem diversas aplicações ¿ controle passivo/ativo de vibração, ?ltros/barreiras acústicas, metamateriais para captação de energia, guias de onda, dentre outras. A principal aplicação considerada nesta tese é o controle passivo de vibração. Primeiro, as formulações do PWE, IPWE e EPWE são apresentadas para alguns casos e vantagens e limitações são discutidas. Os casos considerados são PnCs 1D de barra, cristais sônicos 2D e EMs 1D de viga de Euler-Bernoulli. Posteriormente, alguns exemplos de propagação de ondas mecânicas nestas estruturas periódicas são abordados através da análise da estrutura de banda. Em seguida, algumas aplicações dos PnCs e EMs para controle passivo de vibração são discutidas em artigos anexados. Inicialmente, a estrutura de banda e a resposta forçada harmônica de um PnC simples de viga de Euler-Bernoulli são calculadas. Vários métodos são aplicados e os resultados simulados podem localizar a posição e a largura das bandas proibidas de Bragg próximas dos resultados experimentais. Posteriormente, é considerada a formação de bandas proibidas de ondas de ?exão em um PnC de placa com diferentes inclusões em redes quadrada e triangular, considerando-se a teoria de Mindlin-Reissner. O melhor desempenho é encontrado para a inclusão com seção transversal circular em uma rede triangular. Em seguida, a estrutura de banda de ondas elásticas se propagando em PnCs com nanoestruturas de carbono e em nanocristais fonônicos piezoelétricos com diferentes tipos de rede e inclusão são calculadas. Bandas proibidas totais entre os modos XY e Z são observadas para todos os tipos de inclusão. A piezoeletricidade in?uencia signi?cativamente as bandas proibidas para inclusão circular vazada em frequências mais baixas. Posteriormente, um PnC magnético-elétrico-elástico 2D é considerado. Diferentes tipos de rede e de inclusão também são considerados. A piezoeletricidade e o piezomagnetismo in?uenciam signi?cativamente as bandas proibidas. Finalmente, são considerados EMs 1D de viga de Euler-Bernoulli e 2D de placa ?na. A in?uência de ressonadores de um grau de liberdade e de múltiplos graus de liberdade periodicamente conectados nas células unitárias do EM de viga de Euler-Bernoulli e EM 2D de placa ?na são investigadas. Diferentes con?gurações da distribuição dos ressonadores são consideradas para investigar os mecanismos de formação das bandas proibidas, isto é, ressonância local e espalhamento de BraggAbstract: In this thesis, plane wave expansion (PWE), improved plane wave expansion (IPWE) and extended plane wave expansion (EPWE) methods are used in order to obtain the band structure of one- (1D) and two-dimensional (2D) phononic crystals (PnCs) and elastic metamaterials (EMs), i.e., arti?cial structures designed to open up Bragg-type and/or locally resonant band gaps. Such periodic structures are being applied in many branches of science, and have many applications ¿ passive/active vibration control, acoustic barriers/?lters, metamaterials-based enhanced energy harvesting, waveguides, among others. The main application considered in this thesis is passive vibration control. First, PWE, IPWE and EPWE formulations are presented for some cases and advantages and drawbacks are discussed. The cases regarded are 1D PnC rods, 2D sonic crystals and 1D EM Euler-Bernoulli beams. Afterwards, some examples of mechanical wave propagation in these periodic structures are addressed by means of band structure analysis. Next, some applications of PnCs and EMs for passive vibration control are discussed in attached papers. Initially, the band structure and harmonic forced response of a simple 1D PnC Euler-Bernoulli beam are carried out. Several approaches are applied and the simulated results can localize the Bragg-type band gap position and width close to the experimental results. Next, it is considered the formation of ?exural wave band gaps in a PnC plate with different inclusions in square and triangular lattices, considering Mindlin-Reissner theory. The best performance is found for circular cross section inclusion in a triangular lattice. Afterwards, the band structure of elastic waves propagating in carbon nanostructure PnCs and nano-piezoelectric PnCs with different types of lattice and inclusion are calculated. Full band gaps between XY and Z modes are observed for all types of inclusions. Piezoelectricity in?uences signi?cantly the band gaps for hollow circular inclusion in lower frequencies. After that, a magnetoelectroelastic 2D PnC is considered. Different types of lattice and inclusion are also addressed. Piezoelectricity and piezomagnetism in?uence signi?cantly the band gaps. Finally, elastic wave propagating in 1D EM Euler-Bernoulli beams and in 2D EM thin plates is regarded. The in?uence of single degree of freedom and multiple degrees of freedom resonators periodically attached in unit cells of the EM Euler-Bernoulli beam and 2D EM thin plate are investigated. Different con?gurations of resonator distribution are carried out in order to investigate the band gap formation mechanisms, i.e., local resonance and Bragg scatteringDoutoradoMecanica dos Sólidos e Projeto MecanicoDoutor em Engenharia Mecânic

Temporal variation in the occurrence of whale and dolphin species in the Azores from 2010 to 2017

Global climate change (CC) affects marine mammals, such as cetaceans, by exposing them to an altered marine environment. Cetaceans are indirectly influenced by CC (e.g. through their prey, warmer environment). They are indicator species, significant to marine ecosystems and one of the most endangered vertebrate groups on this planet. Since oceanic water temperatures have increased, a noticeable shift in diversity of cetaceans present in marine hotspots is expected. In this paper, the community structure (occurrence) of cetacean species present around São Miguel Island, Portugal were investigated to contribute to the current understanding of the effects of CC on cetaceans

Samen kiezen, samen delen?:De invloed van waardenoriëntaties van levenspartners op de geboorte van kinderen en de taakverdeling

In this article, we examine effects of partners' values on the birth of a child, division of domestic labor, division of childcare and division of paid labor of couples. We use panel data from the Panel Study of Social Integration in the Netherlands (PSIN), that include independent measures of partners' values in one wave (1995) and family life behavior in the next wave (1999). Two kinds of values are distinguished: values towards women's emancipation and values towards children. Using theories about 'decision rules' we formulated hypotheses about possible outcomes when partners have dissimilar values. The results show that partners' values are not always identical. Furthermore, values of both partners are found to be equally important in joint decisions. No evidence is found for male or female dominance in values. Partners' values towards children affect mainly choices concerning children and work. Partners' values towards emancipation play a role in choices concerning division of labor within a household

Critical assessment of human metabolic pathway databases: a stepping stone for future integration

<p>Abstract</p> <p>Background</p> <p>Multiple pathway databases are available that describe the human metabolic network and have proven their usefulness in many applications, ranging from the analysis and interpretation of high-throughput data to their use as a reference repository. However, so far the various human metabolic networks described by these databases have not been systematically compared and contrasted, nor has the extent to which they differ been quantified. For a researcher using these databases for particular analyses of human metabolism, it is crucial to know the extent of the differences in content and their underlying causes. Moreover, the outcomes of such a comparison are important for ongoing integration efforts.</p> <p>Results</p> <p>We compared the genes, EC numbers and reactions of five frequently used human metabolic pathway databases. The overlap is surprisingly low, especially on reaction level, where the databases agree on 3% of the 6968 reactions they have combined. Even for the well-established tricarboxylic acid cycle the databases agree on only 5 out of the 30 reactions in total. We identified the main causes for the lack of overlap. Importantly, the databases are partly complementary. Other explanations include the number of steps a conversion is described in and the number of possible alternative substrates listed. Missing metabolite identifiers and ambiguous names for metabolites also affect the comparison.</p> <p>Conclusions</p> <p>Our results show that each of the five networks compared provides us with a valuable piece of the puzzle of the complete reconstruction of the human metabolic network. To enable integration of the networks, next to a need for standardizing the metabolite names and identifiers, the conceptual differences between the databases should be resolved. Considerable manual intervention is required to reach the ultimate goal of a unified and biologically accurate model for studying the systems biology of human metabolism. Our comparison provides a stepping stone for such an endeavor.</p

Microscopia eletrônica de varredura da interação entre Cryptococcus magnus e Colletotrichum gloeosporioides em frutos de mamão

ABSTRACTThe objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides) on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after harvest. Results showed that C. magnus is able to colonize wound surfaces much faster than the pathogen, outcompeting the later for space and probably for nutrients. In addition, C. magnus produces a flocculent matrix, which affects hyphae integrity. The competition for space and the production of substances that affect hyphae integrity are among the most important modes of action of this yeast. ______________________________________________________________________________ RESUMOO objetivo deste trabalho foi investigar prováveis modos de ação da levedura Cryptococcus magnus, que resultam no controle da antracnose (Colletotrichum gloeosporioides) em frutos de mamoeiro na póscolheita. A microscopia eletrônica de varredura foi utilizada para avaliar o efeito da levedura sobre inoculações realizadas após a colheita. Os resultados mostraram que C. magnus é capaz de colonizar a superfície de ferimentos nos frutos e vencer a competição por espaço e, provavelmente, por nutrientes. Além disso, C. magnus produz uma matriz de textura característica que afeta a integridade da hifa do patógeno. A competição por espaço e a produção de substâncias que afetam a integridade das hifas estão entre os mais importantes modos de ação desta levedura

ELASTIC WAVE BAND GAPS IN A TWO-DIMENSIONAL MAGNETOELECTROELASTIC PHONONIC CRYSTAL

In this study we investigated the band structure of elastic waves propagating in a magnetoelectroelastic phononic crystal (MPC), consisting of a polymer matrix reinforced by BaTiO3”“CoFe2O4 inclusions in a square, triangular and honeycomb lattices. We also studied the influence of the inclusion geometry cross section ”“ circular, hollow circular, square and rotated square with a 45° angle of rotation with respect to the x, y axes. The plane wave expansion (PWE) method was used to solve the constitutive equations of a magnetoelectroelastic material considering the wave propagation in the xy plane (longitudinal-transverse vibration, XY mode, and transverse vibration, Z mode). The complete band gaps between the XY and Z modes were observed to all types of inclusion and the best performance depends on the lattice. For square lattice, the best performance was found for square inclusion in lower frequencies, for triangular lattice, the circular, square and rotated square present, approximately, the same behavior and for honeycomb lattice, the best performance was found for circular inclusion