Identification and correction of besouro's faults: impact on test‐driven development experiments

Context. This thesis is framed in experimental software engineering. More concretely, it addresses the problems arisen when assessing process conformance in test-driven development experiments conducted by UPM's Experimental Software Engineering group. Process conformance was studied using the Eclipse's plug-in tool Besouro. It has been observed that Besouro does not work correctly in some circumstances. It creates doubts about the correction of the existing experimental data which render it useless. Aim. The main objective of this work is the identification and correction of Besouro's faults. A secondary goal is fixing the datasets already obtained in past experiments to the maximum possible extent. This way, existing experimental results could be used with confidence. Method. (1) Testing Besouro using different sequences of events (creation methods, assertions etc..) to identify the underlying faults. (2) Fix the code and (3) fix the datasets using code specially created for this purpose. Results. (1) We confirmed the existence of several fault in Besouro's code that affected to Test-First and Test-Last episode identification. These faults caused the incorrect identification of 20% of episodes. (2) We were able to fix Besouro's code. (3) The correction of existing datasets was possible, subjected to some restrictions (such us the impossibility of tracing code size increase to programming time. Conclusion. The results of past experiments dependent upon Besouro's data could no be trustable. We have the suspicion that more faults remain in Besouro's code, whose identification requires further analysis

Towards an operationalization of test-driven development skills: An industrial empirical study

Abstract Context: The majority of the empirical studies on Test-driven development (TDD) are concerned with verifying or refuting the effectiveness of the technique over a traditional approach, and they tend to neglect whether the subjects possess the necessary skills to apply TDD, though they argue such skills are necessary. Objective: We evaluate a set of minimal, a priori and in process skills necessary to apply TDD. We determine whether variations in external quality (i.e., number of defects) and productivity (i.e., number of features implemented) can be associated with different clusters of the TDD skills? set. Method: We executed a quasi-experiment involving 30 practitioners from industry. We first grouped the participants according to their TDD skills? set (consisting of a priori experience on programming and testing as well as in-process TDD conformance) into three levels (Low-Medium-High) using k-means clustering. We then applied ANOVA to compare the clusters in terms of external quality and productivity, and conducted post-hoc pairwise analysis. Results: We did not observe a statistically significant difference between the clusters either for external software quality ( F ( 2 , 27 = 1.44 , p = . 260 ), or productivity ( F ( 2 , 27 ) = 3.02 , p = . 065 ). However, the analysis of the effect sizes and their confidence intervals shows that the TDD skills? set is a factor that could account for up to 28% of the external quality, and 38% for productivity. Conclusion: We have reason to conclude that focusing on the improvement of TDD skills? set investigated in this study could benefit software developers in improving their baseline productivity and the external quality of the code they produce. However, replications are needed to overcome the issues related with the statistical power of this study. We suggest practical insights for future work to investigate the phenomenon further.hisresearchispartiallysupportedbytheAcademyofFinlandwithdecisionno.:278354,andbyFinnishDistinguishedProfessor(Fi.Di.Pro.) programme, ESEIL

Understanding Software Development and Testing Practices

A bad software development process leads to wasted effort and inferior products. In order to improve a software process, it must be first understood. In this work I focus on understanding software processes. The first process we seek to understand is Continuous Integration (CI). CI systems automate the compilation, building, and testing of software. Despite CI rising as a big success story in automated software engineering, it has received almost no attention from the research community. For example, how widely is CI used in practice, and what are some costs and benefits associated with CI? Without answering such questions, developers, tool builders, and researchers make decisions based on folklore instead of data. We use three complementary methods to study the usage of CI in open-source projects. To understand which CI systems developers use, we analyzed 34,544 open-source projects from GitHub. To understand how developers use CI, we analyzed 1,529,291 builds from the most commonly used CI system. To understand why projects use or do not use CI, we surveyed 442 developers. With this data, we answered several key questions related to the usage, costs, and benefits of CI. Among our results, we show evidence that supports the claim that CI helps projects release more often, that CI is widely adopted by the most popular projects, as well as finding that the overall percentage of projects using CI continues to grow, making it important and timely to focus more research on CI. Furthermore, we present a qualitative study of the barriers and needs developers face when using CI. In this paper, we conduct 16 semi-structured interviews with developers from different industries and development scales. We triangulate our findings by running two surveys. The Focused Survey samples 51 developers at a single company. The Broad Survey samples a population of 523 developers from all over the world. We identify trade-offs developers face when using and implementing CI. Developers face trade-offs between speed and certainty (Assurance), between better access and information security (Security), and between more configuration options and better ease of use (Flexibility). We present implications of these trade-offs for developers, tool builders, and researchers. Additionally, we seek to use code and test changes to understand conformance to the Test Driven Development (TDD) process. We designed and implemented TDDViz, a tool that supports developers in better understanding how they conform to TDD. TDDViz supports this understanding by providing novel visualizations of developers’ TDD process. To enable TDDViz’s visualizations, we developed a novel automatic inferencer that identifies the phases that make up the TDD process solely based on code and test changes. We evaluate TDDViz using two complementary methods: a controlled experiment with 35 participants to evaluate the visualization, and a case study with 2601 TDD Sessions to evaluate the inference algorithm. The controlled experiment shows that, in comparison to existing visualizations, participants performed significantly better when using TDDViz to answer questions about code evolution. In addition, the case study shows that the inferencing algorithm in TDDViz infers TDD phases with an accuracy (F-measure) of 87%

A Rhetoric Of Technology: The Discourse In U.S. Army Manuals And Handbooks

This dissertation examines the historical technical publications of the United States Army from 1775-2004. Historical research in Army technical communication reveals the persuasive characteristics of its technical publications. Elements of narrative, storytelling, and anthropomorphism are techniques writers used to help deliver information to readers. Research also reveals the design techniques writers adopted to unite the situated literacies of the troops. Analyses of print, comic, and digital media expose the increasing visualization of information since the eighteenth century. The results of such historical research can be applied to new media designs. Automating processes captured in paper-based technical manuals and adding intelligent functionality to these designs are two of many possible design options. Research also dispels a myth concerning the history of modern technical communication and illustrates the development of many genres and subgenres. Modern technical communication was not born of World War II as many scholars suggest, but was a legitimate field in eighteenth-century America. Finally, historical research in Army technical communication shows the systematic progression of a technological society and our increasing dependence on machine intelligence

Computational methods for percussion music analysis : the afro-uruguayan candombe drumming as a case study

Most of the research conducted on information technologies applied to music has been largely limited to a few mainstream styles of the so-called `Western' music. The resulting tools often do not generalize properly or cannot be easily extended to other music traditions. So, culture-specific approaches have been recently proposed as a way to build richer and more general computational models for music. This thesis work aims at contributing to the computer-aided study of rhythm, with the focus on percussion music and in the search of appropriate solutions from a culture specifc perspective by considering the Afro-Uruguayan candombe drumming as a case study. This is mainly motivated by its challenging rhythmic characteristics, troublesome for most of the existing analysis methods. In this way, it attempts to push ahead the boundaries of current music technologies. The thesis o ers an overview of the historical, social and cultural context in which candombe drumming is embedded, along with a description of the rhythm. One of the specific contributions of the thesis is the creation of annotated datasets of candombe drumming suitable for computational rhythm analysis. Performances were purposely recorded, and received annotations of metrical information, location of onsets, and sections. A dataset of annotated recordings for beat and downbeat tracking was publicly released, and an audio-visual dataset of performances was obtained, which serves both documentary and research purposes. Part of the dissertation focused on the discovery and analysis of rhythmic patterns from audio recordings. A representation in the form of a map of rhythmic patterns based on spectral features was devised. The type of analyses that can be conducted with the proposed methods is illustrated with some experiments. The dissertation also systematically approached (to the best of our knowledge, for the first time) the study and characterization of the micro-rhythmical properties of candombe drumming. The ndings suggest that micro-timing is a structural component of the rhythm, producing a sort of characteristic "swing". The rest of the dissertation was devoted to the automatic inference and tracking of the metric structure from audio recordings. A supervised Bayesian scheme for rhythmic pattern tracking was proposed, of which a software implementation was publicly released. The results give additional evidence of the generalizability of the Bayesian approach to complex rhythms from diferent music traditions. Finally, the downbeat detection task was formulated as a data compression problem. This resulted in a novel method that proved to be e ective for a large part of the dataset and opens up some interesting threads for future research.La mayoría de la investigación realizada en tecnologías de la información aplicadas a la música se ha limitado en gran medida a algunos estilos particulares de la así llamada música `occidental'. Las herramientas resultantes a menudo no generalizan adecuadamente o no se pueden extender fácilmente a otras tradiciones musicales. Por lo tanto, recientemente se han propuesto enfoques culturalmente específicos como forma de construir modelos computacionales más ricos y más generales. Esta tesis tiene como objetivo contribuir al estudio del ritmo asistido por computadora, desde una perspectiva cultural específica, considerando el candombe Afro-Uruguayo como caso de estudio. Esto está motivado principalmente por sus características rítmicas, problemáticas para la mayoría de los métodos de análisis existentes. Así , intenta superar los límites actuales de estas tecnologías. La tesis ofrece una visión general del contexto histórico, social y cultural en el que el candombe está integrado, junto con una descripción de su ritmo. Una de las contribuciones específicas de la tesis es la creación de conjuntos de datos adecuados para el análisis computacional del ritmo. Se llevaron adelante sesiones de grabación y se generaron anotaciones de información métrica, ubicación de eventos y secciones. Se disponibilizó públicamente un conjunto de grabaciones anotadas para el seguimiento de pulso e inicio de compás, y se generó un registro audiovisual que sirve tanto para fines documentales como de investigación. Parte de la tesis se centró en descubrir y analizar patrones rítmicos a partir de grabaciones de audio. Se diseñó una representación en forma de mapa de patrones rítmicos basada en características espectrales. El tipo de análisis que se puede realizar con los métodos propuestos se ilustra con algunos experimentos. La tesis también abordó de forma sistemática (y por primera vez) el estudio y la caracterización de las propiedades micro rítmicas del candombe. Los resultados sugieren que las micro desviaciones temporales son un componente estructural del ritmo, dando lugar a una especie de "swing" característico. El resto de la tesis se dedicó a la inferencia automática de la estructura métrica a partir de grabaciones de audio. Se propuso un esquema Bayesiano supervisado para el seguimiento de patrones rítmicos, del cual se disponibilizó públicamente una implementación de software. Los resultados dan evidencia adicional de la capacidad de generalización del enfoque Bayesiano a ritmos complejos. Por último, la detección de inicio de compás se formuló como un problema de compresión de datos. Esto resultó en un método novedoso que demostró ser efectivo para una buena parte de los datos y abre varias líneas de investigación

Single-Cell Genomics of Uncultivated Marine Bacteria

Historically, the difficulty of obtaining pure cultures of abundant marine microbial plankton has an obstacle to reconstructing the underlying mechanisms of biogeochemistry in the ocean. While a number of dominant marine species from the ocean surface have been cultured, the dominant microbial plankton of the dark ocean proved far more difficult to tame. Genomic analyses of single cells emerged as a powerful means to expand knowledge of the diverse biochemical potential of these communities. Chapter 1 reviews the timeline of events in this field and summarizes current research with single-cell genomics and metagenomics within the framework of marine microbial ecology. The defining step in single-cell genomics approaches to environmental studies is the physical isolation of wild-type cells from heterogeneous microbial populations. In Chapter two I detail the construction and application of new instrumentation for optical trapping in conjunction with microfluidic devices (optofluidics) that allows for the selection of individual cells for genome amplification and sequencing. This approach has unique advantages for analyses of rare community members, cells with irregular morphologies, small quantity samples, and studies that employ advanced optical microscopy approaches to cell visualization.Fluorescence-activated cell sorting (FACS) approaches to single-cell genomics have reached full development and have been applied effectively to explore microbial diversity in the deep. In Chapter 3 I explore single amplified genomes obtained with FACS approaches, from several single-amplified genomes (SAGs) of the SAR202 clade, which has been shown to be ubiquitously abundant in the meso- and bathypelagic waters of the open ocean. Prior to this study the metabolism and geochemical role of the SAR202 clade was unknown, but their high abundance suggested they played an important role in nutrient cycling in the dark ocean. Due to their distinctive vertical profile, early accounts of the SAR202 clade speculated that they might be major mediators of recalcitrant organic carbon sequestration and turnover in the deep ocean, contributing to the "microbial carbon pump" through the conversion of labile carbon forms to more heterogeneous and refractory forms that could remain in the deep sea for thousands of years. I discovered that SAR202 encodes several families of oxidative enzymes and hypothesize that they are involved in the cycling of a major class of refractory deep-water marine dissolved organic matter (DOM), known as carboxyl-rich alicyclic matter, or CRAM. In Chapter 4 I revisit the optofluidic approach and describe its use to isolate single-amplified genomes (SAGS) from the marine environment. Several of these SAGs were shown to be representatives of groups of microbial plankton that are abundant in the ocean but not represented by genome sequences. In this chapter we evaluate the performance of this technique for single-cell genomics and outline the encoded metabolic features of three relatively-unstudied groups of marine microbes isolated using this technique. In Chapter 5, I outline potential areas of improvement for the optofluidic technology described in this thesis and discuss where the future of single-cell genomics technology

CIRA annual report FY 2017/2018

Reporting period April 1, 2017-March 31, 2018

Integrated multi-functional morphing aircraft technologies

In the past years, the development of morphing wing technologies has received a great deal of interest from the scientific community. These technologies potentially enable an increase in aircraft efficiency by changing the wing shape, thus allowing the aircraft to fly near its optimal performance point at different flight conditions. This thesis explores the development, analysis, building and integration of two new functional Variable-Span Wing (VSW) concepts to be applied in Remotely Piloted Aircraft Systems (RPAS). Additional studies are performed to synthesize the mass of such morphing concepts and to develop mass prediction models. The VSW concept is composed of one fixed rectangular inboard part, inboard fixed wing (IFW), and a moving rectangular outboard part: outboard moving wing (OMW). An aerodynamic shape optimization code is used to solve a drag minimization problem to determine the optimal values of wingspan for various speeds of the vehicle’s flight envelope. It was concluded that, at low speeds, the original wing has slightly better performance than the VSW and for speeds higher than 25 m/s the opposite occurs, due to the reduction in wing area and consequently the total wing drag. A structural Finite Element Model (FEM) of the VSW is developed, where the interface between wing parts is modelled. Deflections and stresses resulting from static aerodynamic loading conditions showed that the wing is suitable for flight. Flutter critical speed is studied. FEM is used to compute the VSW mode shapes and frequencies of free vibration, considering a rigid or the real flexible interface, showing that the effect of rigidity loss in the interface between the IFW and the OMW, has a negative impact on the critical flutter speed. A full-scale prototype is built using composite materials and an electro-mechanical actuation system is developed using a rack and pinion driven by two servomotors. Bench tests, performed to evaluate the wing and its actuation mechanism under load, showed that the system can perform the required extension/retraction cycles and is suitable to be installed on a RPAS airframe, which has been modified and instrumented to serve as test bed for evaluating the prototype in-flight. Two sets of flight tests are performed: aerodynamic and energy characterization. The former aims at determining the lift-to-drag ratio for different airspeeds and the latter to measure the propulsive and manoeuvring energy when performing a prescribed mission. In the aerodynamic testing, in-flight evaluation of the RPAS fitted with the VSW demonstrates full flight capability and shows improvements produced by the VSW over a conventional fixed wing for speeds above 19 m/s. At low speeds, the original wing has slightly better lift-to-drag ratio than the VSW. Contrarily, at 30 m/s, the VSW in minimum span configuration is 35% better than the original fixed wing. In the other performed test, it is concluded that the VSW fitted RPAS has less overall energy consumption despite the increased vehicle weight. The energy reduction occurs only in the high speed condition but it is so marked that it offsets the increase in energy during takeoff, climb and loiter phases. Following the work on the first VSW prototype, a new telescopic wing that allows the integration of other morphing strategies is developed, within the CHANGE EU project. The wing adopted span change, leading and trailing edge camber changes. A modular design philosophy, based on a wing-box like structure, is implemented, such that the individual systems can be separately developed and then integrated. The structure is sized for strength and stiffness using FEM, based on flight loads derived from the mission requirements. A partial span, fullsized cross-section prototype is built to validate the structural performance and the actuation mechanism capability and durability. The wing is built using composite materials and an electromechanical actuation system with an oil filled nylon rack and pinion is developed to actuate it. The structural static testing shows similar trends when compared with numerical predictions. The actuation mechanism is characterized in terms of actuation speed and specific energy consumption and it was concluded that it functioned within its designed specifications. A full-scale prototype is later built by the consortium and the leading and trailing edge concepts from the different partners integrated in a single wing. Wind tunnel tests confirmed that the wing can withstand the aerodynamic loading. Flight tests are performed by TEKEVER, showing that the modular concept works reliably. From the previous works, it is inferred that morphing concepts are promising and feasible methodologies but present an undesired mass increase due to their inherent complexity. On the other hand, mass prediction methods to aid the design of morphing wings at the conceptual design phase are rare. Therefore, a mass model of a VSW with a trailing edge device is proposed. The structural mass prediction is based on a parametric study. A minimum mass optimization problem with stiffness and strength constraints is implemented and solved, being the design variables structural thicknesses and widths, using a parametric FEM of the wing. The study is done for a conventional fixed wing and the VSW, which are then combined to ascertain the VSW mass increment, i.e., the mass penalization of the adopted morphing concept. Polynomials are found to produce good approximations of the wing mass. Additionally, the effects of various VSW design parameters in the structural mass are discussed. On one hand, it was found that the span and chord have the highest impact in the wing mass. On the other hand, the VSW to fixed wing ratio proved that the influence of span variation ratio in the wing mass is not trivial. It is found that the mass increase does not grow proportionally with span variation ratio increase and that for each combination of span and chord, exists a span variation ratio that minimizes the mass penalty. Using the VSW to fixed wing ratio function, the mass model is derived. To ascertain its accuracy, a case study is performed, which demonstrated prediction errors below 10%. Although the mass model results are encouraging, more case studies are necessary to prove its applicability over a wide range of VSWs. The work performed successfully demonstrated that VSW concepts can achieve considerable geometry changes which, in turn, translate into considerable aerodynamic gains, despite the increased weight. They influence all aspects of the wing design, from the structural side to the actuation mechanisms. The parametric study summarizes the mass penalties of such concepts, being successful at demonstrating that the mass penalty is not straightforward and that a careful selection of span, chord and variable-span ratio can minimize the mass increase.Nos últimos anos, o desenvolvimento de asas adaptativas tem sido alvo de um grande interesse por parte da comunidade científica. Nesta tese explora-se o desenvolvimento, análise, construção e integração de dois novos conceitos de Asas de Envergadura Variável (VSWs) funcionais a serem aplicados em Sistemas de Aeronaves Pilotadas Remotamente (RPASs). Estudos adicionais são levados a cabo para sintetizar a massa desses conceitos e desenvolver modelos de previsão de massa. O conceito da VSW é constituído por uma parte interna retangular fixa, Asa Fixa Interna (IFW), e por uma parte externa retangular móvel, Asa Móvel Externa (OMW). Um código de otimização aerodinâmica é utilizado para minimizar a resistência ao avanço, determinando os valores ótimos de envergadura para várias velocidades de voo do veículo. Concluiu-se que, a baixas velocidades, a asa original apresenta um desempenho ligeiramente melhor que a VSW, enquanto que a velocidades superiores a 25 m/s, a VSW apresenta um desempenho melhor devido à redução da área das asas e, consequentemente, à redução da resistência total das asas. Para levar a cabo um estudo estrutural, foi desenvolvido um Modelo de Elementos Finitos (FEM) estrutural da VSW, no qual se modelou a interface entre a IFW/OMW. As deflexões e tensões resultantes dos carregamentos aerodinâmicos estáticos mostraram que a asa é capaz de suportar as cargas em voo. A velocidade de flutter é também investigada, sendo o FEM utilizado para calcular as formas dos modos de vibração da VSW e respetivas frequências de vibração livre. Considerou-se uma interface colada ou flexível, confirmando-se que o efeito da perda de rigidez na interface IFW/OMW, tem um impacto negativo sobre a velocidade de flutter. Um protótipo da VSW é construído, utilizando materiais compósitos, e um sistema de atuação eletromecânico é desenvolvido usando um sistema de pinhão e cremalheira movido por dois servomotores. Os testes de bancada, realizados para avaliar a asa e o mecanismo de atuação, mostraram que o sistema é capaz de realizar a extensão/retração da asa, sendo adequado para ser instalado num RPAS. Este RPAS foi modificado e instrumentado para servir de banco de ensaio para avaliação do protótipo em voo. São realizados dois conjuntos de testes de voo: caracterização aerodinâmica e energética. O primeiro incide na determinação da razão de planeio para diferentes velocidades e o segundo é levado a cabo para determinar a energia propulsiva e de manobra ao executar uma missão típica. Nos testes aerodinâmicos ficou comprovado que o RPAS equipado com a VSW é capaz de uma normal operação e ainda que mostra melhorias sobre uma asa fixa convencional para velocidades acima de 19 m/s. A velocidades mais reduzidas, a asa original tem um desempenho ligeiramente melhor do que a VSW. Por outro lado, a 30 m/s, a VSW na configuração de envergadura mínima é 35% melhor do que a asa fixa original. No outro ensaio realizado, conclui-se que o RPAS de envergadura variável tem menos consumo de energia global, apesar do aumento de peso do veículo. A redução de energia ocorre apenas na fase de cruzeiro de alta velocidade, mas foi tão acentuada que compensou o aumento da energia durante as fases de descolagem, subida e espera. Na sequência do trabalho anterior e no âmbito do projeto europeu CHANGE, é desenvolvida uma nova VSW que permite a integração de outras estratégias adaptativas. A nova asa adotou a mudança de envergadura, e a mudança de curvatura nos bordos de ataque e de fuga. Esta adotou uma filosofia de projeto modular, baseada numa caixa de torção, permitindo o desenvolvimento das diferentes tecnologias adaptativas separadamente. A estrutura é divmensionada para resistência e rigidez usando FEM, com base em cargas de voo derivadas dos requisitos da missão. Um primeiro protótipo é construído para validar o desempenho estrutural e a funcionalidade do mecanismo de atuação. A asa é construída usando materiais compósitos e utiliza um sistema de pinhão e cremalheira e um servomotor, para variar a envergadura. Testes estruturais estáticos mostram que as deflexões corroboram as previsões numéricas. O mecanismo de atuação é caracterizado em termos de velocidade de atuação e consumo de energia específica, concluindo-se que funciona dentro do previsto. O segundo protótipo é construído pelo consórcio e os conceitos de bordo de ataque e de fuga são integrados. Testes em túnel de vento confirmaram que a asa suporta o carregamento aerodinâmico. Os testes de voo, realizados pela TEKEVER, mostram que o conceito modular funciona de forma fiável. Baseado nos trabalhos anteriores, conclui-se que os conceitos adaptativos são promissores e viáveis, mas apresentam um aumento de massa indesejável devido à sua inerente complexidade. Por outro lado, os métodos de previsão de massa para auxiliar o projeto de asas adaptativas na fase de projeto conceitual são raros. Deste modo, um modelo de massa da VSW com um dispositivo de borda de fuga é proposto. A previsão de massa estrutural é baseada num estudo paramétrico. Um problema de minimização de massa com constrangimentos de rigidez e resistência é implementado e resolvido, sendo as variáveis de projeto espessuras e larguras estruturais. Para o levar a cabo, um FEM paramétrico da VSW é desenvolvido. O estudo é feito para uma asa fixa convencional e para a VSW, os quais são combinados para determinar o incremento de massa da VSW. Aproximações polinomiais das massas da asa são produzidas, mostrando serem capazes de produzir uma adequada representação. Adicionalmente, são discutidos os efeitos dos vários parâmetros de design da VSW na massa estrutural. Por um lado, verificou-se que a envergadura e a corda têm o maior impacto na massa da asa. Por outro lado, a razão de massas da VSW e da asa fixa provou que a influência da razão de variação de envergadura na massa das asas não é trivial. Verifica-se que o aumento de massa não cresce proporcionalmente com o aumento da razão de variação de envergadura e que para um dado conjunto de envergadura e corda existe uma razão de variação de envergadura que minimiza o aumento de massa. O modelo de massa é derivado usando a aproximação polinomial da razão da VSW com a asa fixa. Para verificar a precisão do modelo, é realizado um caso de estudo que demonstrou erros de previsão abaixo dos 10%. Embora os resultados do modelo de massa sejam encorajadores, mais casos de estudo são necessários para provar a sua aplicabilidade a uma ampla gama de VSW. O trabalho realizado demonstrou com sucesso que os conceitos de VSW podem alcançar consideráveis mudanças de geometria, que se traduzem em ganhos aerodinâmicos consideráveis, apesar do aumento de peso. Estes influenciam todos os aspetos do projeto da asa, desde a parte estrutural até aos mecanismos de atuação. O estudo paramétrico tentou resumir a penalização de massa de tais conceitos, sendo bem sucedido em demonstrar que esta penalização não é simples e que uma seleção cuidadosa de envergadura, corda e razão de variação de envergadura pode minimizar o aumento de peso.This thesis and the associated research was partially funded by the European Community’s Seventh Framework Programme (FP7) under the Grant Agreement 314139