14 research outputs found

    An Approach Based on Particle Swarm Optimization for Inspection of Spacecraft Hulls by a Swarm of Miniaturized Robots

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    The remoteness and hazards that are inherent to the operating environments of space infrastructures promote their need for automated robotic inspection. In particular, micrometeoroid and orbital debris impact and structural fatigue are common sources of damage to spacecraft hulls. Vibration sensing has been used to detect structural damage in spacecraft hulls as well as in structural health monitoring practices in industry by deploying static sensors. In this paper, we propose using a swarm of miniaturized vibration-sensing mobile robots realizing a network of mobile sensors. We present a distributed inspection algorithm based on the bio-inspired particle swarm optimization and evolutionary algorithm niching techniques to deliver the task of enumeration and localization of an a priori unknown number of vibration sources on a simplified 2.5D spacecraft surface. Our algorithm is deployed on a swarm of simulated cm-scale wheeled robots. These are guided in their inspection task by sensing vibrations arising from failure points on the surface which are detected by on-board accelerometers. We study three performance metrics: (1) proximity of the localized sources to the ground truth locations, (2) time to localize each source, and (3) time to finish the inspection task given a 75% inspection coverage threshold. We find that our swarm is able to successfully localize the present so

    Fedco Seeds 2021: Seeds and Supplies

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    When is a seed catalog more than a seed catalog? When it is the Fedco Seed catalog. Fedco, founded in 1978, is a worker-consumer cooperative in Maine known for promoting the ideals of cooperation, transparency, and the common ownership of seeds. These archives contain thousands of pages of Fedco’s seed catalogs. As one of its editors noted, “We give our readers things to think about.” Annual themes have included the role played by soil bacteria—the microscopic heroes that make life on this planet possible; the contributions of plant breeders and seed keepers; poetry by Walt Whitman, Vergil, and Russell Libby, among others. Editorials often stress the negative impact multinational corporations have on the genetic diversity of food crops, and provide annual updates on genetic engineering and the consolidation of the seed industry. Bits of humor are throughout, some of them in possibly the catalogs’ best feature: original art, and engravings from old seed catalogs and horticultural books. It is, in the words of Fedco’s founder CR Lawn, “More than a marketing tool.

    A Generic method for assembling software product line components

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    Software product lines (SPL) facilitate the industrialization of software development. The main goal is to create a set of reusable software components for the rapid production of a software systems family. Many authors propose different approaches to implement and assemble the reusable components of an SPL. However, the construction and assembly of these components continue to be a complex and time-consuming process. This thesis analyzes the advantages and disadvantages of the current approaches to implement and assemble the reusable components of an SPL. Taking advantage of these elements and with the goal of developing a generic method (which can be applied to several software components developed in different software languages), we develop Fragment-oriented programming (FragOP), a framework to design, implement and reuse SPL domain components. FragOP is based on: (i) domain components, (ii) domain files, (iii) fragmentation points, (iv) fragments, (v) customization points, and (vi) customization files. FragOP was implemented in an open-source tool called VariaMos, and we also carried out three evaluations: (i) we created a clothing stores SPL, derived five different products, and discussed the results. (ii) We developed a discussion about the comparison between FragOP and other approaches. And (iii) we designed and executed a usability test of VariaMos to support the FragOP approach. The results show preliminary evidence that the use of FragOP reduces the manual intervention when assembling SPL domain components and it can be used as a generic method for assembling assets and SPL components developed in different software languages.Las líneas de productos de software (LPS) promueven la industrialización del desarrollo de software mediante la definición y ensamblaje de componentes reutilizables de software. Actualmente existen diferentes propuestas para implementar y ensamblar estos componentes. Sin embargo, su construcción y ensamblaje continúa siendo un proceso complejo y que requiere mucho tiempo. Esta tesis analiza las ventajas y desventajas de las diferentes estrategias actuales para implementación y ensamblaje de componentes de LPS. Con base en esto y con el objetivo de desarrollar un método genérico (el cual se pueda aplicar a múltiples componentes de software desarrollados en diferentes lenguajes), esta tesis desarrolla la programación orientada a fragmentos (FragOP), la cual define un marco de trabajo para diseñar, implementar y reutilizar componentes de dominio de LPS. FragOP se basa en: (i) componentes de dominio, (ii) archivos de dominio, (iii) puntos de fragmentación, (iv) fragmentos, (v) puntos de personalización, y (vi) archivos de personalización. Además, se realizó una implementación de FragOP en una herramienta llamada VariaMos, y se llevaron a cabo tres evaluaciones: (i) se creó una LPS de tiendas de ropa, se derivaron cinco productos y se discutieron los resultados. (ii) Se realizó una discusión acerca de la comparación de FragOP y otras propuestas actuales. Y (iii) se diseñó una prueba de usabilidad acerca del soporte de VariaMos para FragOP. Los resultados muestran evidencia preliminar de que el uso de FragOP reduce la intervención manual cuando se ensamblan componentes, y que FragOP puede usarse como un método genérico para el ensamblaje de componentes.Doctorad

    WeaFQAs: A Software Product Line Approach for Customizing and Weaving Efficient Functional Quality Attributes

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    Fecha de Lectura de Tesis: 10 de julio de 2018Los atributos de calidad funcionales (FQA) son aquellos que tienen una clara implicación en la funcionalidad del sistema, es decir, existen unos componentes específicos que deben ser incorporados a la arquitectura software del sistema para satisfacer sus requisitos de atributos de calidad. Ejemplos de FQAs son seguridad, usabilidad, o persistencia. Modelar estos atributos es una tarea compleja. Por un lado, se componen de muchas características relacionadas, por ejemplo seguridad está compuesto, entre otros, por autenticación, confidencialidad y encriptación. Tienen dependencias entre ellos, por ejemplo, seguridad puede ser requerido por usabilidad o persistencia. Por otro lado, tienen muchos puntos de variabilidad: una aplicación concreta puede requerir autenticación y control de acceso mientras que otra puede necesitar sólo encriptación. Además, su funcionalidad suele estar dispersa afectando a varios componentes del sistema en desarrollo. El objetivo de esta tesis es definir una línea de productos software orientada a aspectos que permita: (1) modelar las similitudes y la variabilidad de los FQAs desde las primeras etapas del proceso de desarrollo, (2) gestionar las dependencias existentes entre los FQAs, (3) independizar el modelado de los FQAs de la arquitectura de la aplicación afectada, (4) configurar los FQAs en base a los requisitos de cada aplicación teniendo además en cuenta propiedades no funcionales como el rendimiento y el consumo energético de cada solución, (5) incorporar las configuraciones a la arquitectura de la aplicación de manera automática; y (6) gestionar la evolución de los FQAs cuando los requisitos cambien en el futuro. Como resultado se ha definido WeaFQAs, un proceso software para gestionar los FQAs que cubre todos los puntos mencionados. Se han realizado y comparado dos instanciaciones de WeaFQAs usando diferentes lenguajes de variabilidad y de modelado, además de proporcionar soporte con una herramienta basada en el lenguaje CVL

    A survey on quality attributes in servicebased systems

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    Service-based systems have become popular in the software industry. In software engineering, it is widely acknowledged that requirements on quality attributes (e.g., performance, security, reliability) significantly impact the design of software systems. This study explores the role of quality attributes during the design of service-based systems. We investigate the significance of quality attributes when designing service-based systems and how quality attributes are addressed through design decisions, across application domains, and related to other aspects of software development, e.g., architecture documentation. We conducted a descriptive survey. The survey was done as an online questionnaire targeting practitioners. Furthermore, we included researchers with practical design experience. We obtained 56 valid responses. Most survey participants consider quality attributes and functionality as equally important and treat quality attributes explicitly rather than implicitly. Furthermore, dependability is the most relevant quality attribute in service-based systems; we do not find quality attributes that are particularly important in specific application domains. Most quality attributes are addressed by ad hoc decisions, rather than established architecture or design patterns or technologies. Only few decision alternatives are considered when making architectural decisions to address quality attributes. Our results partially confirm anecdotal evidence from current literature, but also strengthen previous claims by providing empirical evidence. Our results point to future research directions (e.g., exploring the impact of decision types on how well quality attributes can be achieved) and implications for practitioners (e.g., training makes a difference to how quality attributes are treated).Peer ReviewedPostprint (author’s final draft

    Variability in Software Systems – Extracted Data and Supplementary Material from a Systematic Literature Review

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    Variability in Software Systems – Extracted Data and Supplementary Material from a Systematic Literature Review

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    The Granite Monthly, a New Hampshire magazine, devoted to literature, history, and state progress. vol. 61

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    Covers January - December, 1929. Vol. LXI, Nos. 1-1
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