825 resultados para declarative and procedural knowledge
Resumo:
Visualization of program executions has been found useful in applications which include education and debugging. However, traditional visualization techniques often fall short of expectations or are altogether inadequate for new programming paradigms, such as Constraint Logic Programming (CLP), whose declarative and operational semantics differ in some crucial ways from those of other paradigms. In particular, traditional ideas regarding flow control and the behavior of data often cannot be lifted in a straightforward way to (C)LP from other families of programming languages. In this paper we discuss techniques for visualizing program execution and data evolution in CLP. We briefly review some previously proposed visualization paradigms, and also propose a number of (to our knowledge) novel ones. The graphical representations have been chosen based on the perceived needs of a programmer trying to analyze the behavior and characteristics of an execution. In particular, we concéntrate on the representation of the program execution behavior (control), the runtime valúes of the variables, and the runtime constraints. Given our interest in visualizing large executions, we also pay attention to abstraction techniques, Le., techniques which are intended to help in reducing the complexity of the visual information.
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CIAO is an advanced programming environment supporting Logic and Constraint programming. It offers a simple concurrent kernel on top of which declarative and non-declarative extensions are added via librarles. Librarles are available for supporting the ISOProlog standard, several constraint domains, functional and higher order programming, concurrent and distributed programming, internet programming, and others. The source language allows declaring properties of predicates via assertions, including types and modes. Such properties are checked at compile-time or at run-time. The compiler and system architecture are designed to natively support modular global analysis, with the two objectives of proving properties in assertions and performing program optimizations, including transparently exploiting parallelism in programs. The purpose of this paper is to report on recent progress made in the context of the CIAO system, with special emphasis on the capabilities of the compiler, the techniques used for supporting such capabilities, and the results in the áreas of program analysis and transformation already obtained with the system.
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The purpose of this investigation was the determination of the aerodynamic performance of sails and gain knowledge of the phenomena involved in order to improve the aerody¬namic characteristics. In this research, the airflow around different sails in four scenarios was studied. The method to analyze these scenarios was the combination of numerical simulations and experimental tests by taking advantage of the best of each tool. Two different Com¬putational Fluid Dynamic codes were utilized: the ANSYS-CFX and the CD-Adapco’s STAR-CCM+. The experimental tests were conducted in the Atmospheric Boundary Layer Wind Tunnel at the Universidad de Granada (Spain), the Twisted Flow Wind Tunnel at the University of Auckland (New Zealand) and the A9 Wind Tunnel at the Universidad Polit´ecnica de Madrid (Spain). Through this research, it was found the three-dimensional effect of the mast on the aerodynamic performance of an IMS Class boat. The pressure distribution on a Transpac 52 Class mainsail was also determined. Moreover, the aerodynamic perfor¬mance of the 43ft and 60ft Dhow Classes was obtained. Finally, a feasibility study was conducted to use a structural wing in combination with conventional propulsions systems. The main conclusion was that this research clarified gaps on the knowledge of the aerodynamic performance of sails. Moreover, since commercial codes were not specifically designed to study sails, a procedure was developed. On the other hand, innovative experimental techniques were used and applied to model-scale sails. The achievements of this thesis are promising and some of the results are already in use by the industry on a daily basis. El propósito de este estudio era determinar el comportamiento aerodinámico de unas velas y mejorar el conocimiento de los fenómenos que suceden para optimizar las características aerodinámicas de dichas velas. En esta investigación se estudió el flujo de aire alrededor de diferentes velas en cuatro escenarios. El método para analizar estos escenarios fue la combinación de simulaciones numéricas y ensayos experimentales mediante el aprovechamiento de las ventajas de cada herramienta. Se utilizaron dos códigos de dinámica de fluidos computacional: el ANSYS-CFX y el STAR-CCM+ de la empresa CD-Adapco. Los ensayos experimentales se desarrollaron en el túnel de viento de capa límite de la Universidad de Granada (España), el túnel de viento de la Universidad de Auckland (Nueva Zelanda) y en el túnel A9 de la Universidad Politécnica de Madrid (España). Mediante esta investigación, se determinó el efecto tridimensional del mástil en un velero de la clase IMS. También se describió la distribución de presiones sobre una mayor de un Transpac 52. Además, se obtuvo el comportamiento aerodinámico de las clases 43ft y 60ft de los veleros Dhows. Finalmente, se llevó a cabo un estudio de viabilidad de la utilización de un ala estructural en combinación con sistemas de propulsión convencionales. La conclusión principal de esta investigación fue la capacidad de explicar ciertas lagunas en el conocimiento del comportamiento aerodinámico de las velas en diferentes escenarios. Además, dado que los códigos comerciales no están específicamente diseñados para el estudio de velas, se desarrolló un procedimiento a tal efecto. Por otro lado, se han utilizado innovadoras técnicas experimentales y se han aplicado a modelos de velas a escala. Los logros de esta investigación son prometedores y algunos de los resultados obtenidos ya están siendo utilizados por la industria en su día a día.
Resumo:
Visualisation of program executions has been used in applications which include education and debugging. However, traditional visualisation techniques often fall short of expectations or are altogether inadequate for new programming paradigms, such as Constraint Logic Programming (CLP), whose declarative and operational semantics differ in some crucial ways from those of other paradigms. In particular, traditional ideas regarding the behaviour of data often cannot be lifted in a straightforward way to (C)LP from other families of programming languages. In this chapter we discuss techniques for visualising data evolution in CLP. We briefly review some previously proposed visualisation paradigms, and also propose a number of (to our knowledge) novel ones. The graphical representations have been chosen based on the perceived needs of a programmer trying to analyse the behaviour and characteristics of an execution. In particular, we concentrate on the representation of the run-time values of the variables, and the constraints among them. Given our interest in visualising large executions, we also pay attention to abstraction techniques, i.e., techniques which are intended to help in reducing the complexity of the visual information.
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One of the advantages of social networks is the possibility to socialize and personalize the content created or shared by the users. In mobile social networks, where the devices have limited capabilities in terms of screen size and computing power, Multimedia Recommender Systems help to present the most relevant content to the users, depending on their tastes, relationships and profile. Previous recommender systems are not able to cope with the uncertainty of automated tagging and are knowledge domain dependant. In addition, the instantiation of a recommender in this domain should cope with problems arising from the collaborative filtering inherent nature (cold start, banana problem, large number of users to run, etc.). The solution presented in this paper addresses the abovementioned problems by proposing a hybrid image recommender system, which combines collaborative filtering (social techniques) with content-based techniques, leaving the user the liberty to give these processes a personal weight. It takes into account aesthetics and the formal characteristics of the images to overcome the problems of current techniques, improving the performance of existing systems to create a mobile social networks recommender with a high degree of adaptation to any kind of user.
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The Common European Framework of Reference for Languages (CEFR) "describes in a comprehensive way what language learners have to learn to do in order to use a language for communication and what knowledge and skills they have to develop so as to be able to act effectively" (Council of Europe, 2001: 1). This paper reports on the findings of two studies whose purpose was to assess written production competence descriptors meant for their inclusion into the Academic and Professional English Language Portfolio KELP) for students of engineering and architecture. The main objective of these studies was to establish whether the language competence descriptors were a satisfactory valid tool in their language programmes from the point of view of clarity, relevance and reliability, as perceived by the students and fellow English for Academic Purposes (RAP) / English for Science and Technology (EST) instructors. The studies shed light on how to improve unsatisfactory descriptors. Results show that the final descriptor lists were on the whole well calibrated and fairly well written: the great majority was considered valid for both teachers and students involved.
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Doñana, a National Park since 1969, a UNESCO site since 1994 among other protected area designations of national and international character, is a coastal dune and marshland ecosystem of outstanding importance for biodiversity and conservation at the mouth of the Guadalaquivir River, Southwest Spain. However, the Doñana natural area is seriously threatened by global change factors such as humanly induced climate change, habitat loss, overexploitation of ecosystem services, and pollution. Not all stakeholders are convinced of the benefits of the national park, and management of Doñana, its environs and watershed are the subject of intense disagreement. This interplay between natural characteristics of great value with intense human pressure makes Doñana a fascinating workshop for the study of global human environment interactions. Here, we discuss the role of stakeholders in the application of a cellular automatabased model to Doñana and its environs and present the results of a series of exercises undertaken with stakeholders to parametrize the model, something often done by researchers without stakeholder engagement. By engaging with stakeholders early in the project, feedback generated from workshops contributes to model development. Stakeholders are therefore contributors of empirical data for the model as well as independent evaluators providing local and specialist knowledge.
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This paper introduces a semantic language developed with the objective to be used in a semantic analyzer based on linguistic and world knowledge. Linguistic knowledge is provided by a Combinatorial Dictionary and several sets of rules. Extra-linguistic information is stored in an Ontology. The meaning of the text is represented by means of a series of RDF-type triples of the form predicate (subject, object). Semantic analyzer is one of the options of the multifunctional ETAP-3 linguistic processor. The analyzer can be used for Information Extraction and Question Answering. We describe semantic representation of expressions that provide an assessment of the number of objects involved and/or give a quantitative evaluation of different types of attributes. We focus on the following aspects: 1) parametric and non-parametric attributes; 2) gradable and non-gradable attributes; 3) ontological representation of different classes of attributes; 4) absolute and relative quantitative assessment; 5) punctual and interval quantitative assessment; 6) intervals with precise and fuzzy boundaries
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This work shows a numerical procedure for bond between indented wires and concrete, and the coupled splitting of the concrete. The bond model is an interface, non-associative, plasticity model. It is coupled with a cohesive fracture model for concrete to take into account the splitting of such concrete. The radial component of the prestressing force, increased by Poisson’s effect, may split the surrounding concrete, decreasing the wire confinement and diminishing the bonding. The combined action of the bond and the splitting is studied with the proposed model. The results of the numerical model are compared with the results of a series of tests, such as those which showed splitting induced by the bond between wire and concrete. Tests with different steel indentation depths were performed. The numerical procedure accurately reproduces the experimental records and improves knowledge of this complex process.
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The aviation companies are facing some problems that argue in favor of biofuels: Rising cost of traditional fuel: from 0.71 USD/gallon in May 2003 to 3.09 USD/gallon in January 2012. Environmental concerns: direct emissions from aviation account for about 3 % of the EU’s total greenhouse gas emissions. The International Civil Aviation Organization (ICAO) forecasts that by 2050 they could grow by a further 300-700 %. On December 20th 2006 the European Commission approved a law proposal to include the civil aviation sector in the European market of carbon dioxide emission rights (European Union Emissions Trading System, EUETS)
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This paper presents the knowledge model of a distributed decision support system, that has been designed for the management of a national network in Ukraine. It shows how advanced Artificial Intelligence techniques (multiagent systems and knowledge modelling) have been applied to solve this real-world decision support problem: on the one hand its distributed nature, implied by different loci of decision-making at the network nodes, suggested to apply a multiagent solution; on the other, due to the complexity of problem-solving for local network administration, it was useful to apply knowledge modelling techniques, in order to structure the different knowledge types and reasoning processes involved. The paper sets out from a description of our particular management problem. Subsequently, our agent model is described, pointing out the local problem-solving and coordination knowledge models. Finally, the dynamics of the approach is illustrated by an example.
Resumo:
Una gestión más eficiente y equitativa del agua a escala de cuenca no se puede centrar exclusivamente en el recurso hídrico en sí, sino también en otras políticas y disciplinas científicas. Existe un consenso creciente de que, además de la consideración de las cambiantes condiciones climáticas, es necesaria una integración de ámbitos de investigación tales como la agronomía, planificación del territorio y ciencias políticas y económicas a fin de satisfacer de manera sostenible las demandas de agua por parte de la sociedad y del medio natural. La Política Agrícola Común (PAC) es el principal motor de cambio en las tendencias de paisajes rurales y sistemas agrícolas, pero el deterioro del medio ambiente es ahora una de las principales preocupaciones. Uno de los cambios más relevantes se ha producido con la expansión e intensificación del olivar en España, principalmente con nuevas zonas de regadío o la conversión de olivares de secano a sistemas en regadío. Por otra parte, el cambio de las condiciones climáticas podría ejercer un papel importante en las tendencias negativas de las aportaciones a los ríos, pero no queda claro el papel que podrían estar jugando los cambios de uso de suelo y cobertura vegetal sobre las tendencias negativas de caudal observadas. Esta tesis tiene como objetivo mejorar el conocimiento de los efectos de la producción agrícola, política agraria y cambios de uso de suelo y cobertura vegetal sobre las condiciones de calidad del agua, respuesta hidrológica y apropiación del agua por parte de la sociedad. En primer lugar, el estudio determina las tendencias existentes de nitratos y sólidos en suspensión en las aguas superficiales de la cuenca del río Guadalquivir durante el periodo de 1998 a 2009. Desde una perspectiva de política agraria, la investigación trata de evaluar mediante un análisis de datos de panel las principales variables, incluyendo la reforma de la PAC de 2003, que están teniendo una influencia en ambos indicadores de calidad. En segundo lugar, la apropiación del agua y el nivel de contaminación por nitratos debido a la producción del aceite de oliva en España se determinan con una evaluación de la huella hídrica (HH), teniendo en cuenta una variabilidad espacial y temporal a largo de las provincias españolas y entre 1997 y 2008. Por último, la tesis analiza los efectos de los cambios de uso de suelo y cobertura vegetal sobre las tendencias negativas observadas en la zona alta del Turia, cabecera de la cuenca del río Júcar, durante el periodo 1973-2008 mediante una modelización ecohidrológica. En la cuenca del Guadalquivir cerca del 20% de las estaciones de monitoreo muestran tendencias significativas, lineales o cuadráticas, para cada indicador de calidad de agua. La mayoría de las tendencias significativas en nitratos están aumentando, y la mayoría de tendencias cuadráticas muestran un patrón en forma de U. Los modelos de regresión de datos de panel muestran que las variables más importantes que empeoran ambos indicadores de calidad del agua son la intensificación de biomasa y las exportaciones de ambos indicadores de calidad procedentes de aguas arriba. En regiones en las que el abandono agrícola y/o desintensificación han tenido lugar han mejorado las condiciones de calidad del agua. Para los nitratos, el desacoplamiento de las subvenciones a la agricultura y la reducción de la cuantía de las subvenciones a tierras de regadío subyacen en la reducción observada de la concentración de nitratos. Las medidas de modernización de regadíos y el establecimiento de zonas vulnerables a nitratos reducen la concentración en subcuencas que muestran una tendencia creciente de nitratos. Sin embargo, el efecto de las exportaciones de nitratos procedente de aguas arriba, la intensificación de la biomasa y los precios de los cultivos presentan un mayor peso, explicando la tendencia creciente observada de nitratos. Para los sólidos en suspensión, no queda de forma evidente si el proceso de desacoplamiento ha influido negativa o positivamente. Sin embargo, los mayores valores de las ayudas agrarias aún ligadas a la producción, en particular en zonas de regadío, conllevan un aumento de las tasas de erosión. Aunque la cuenca del Guadalquivir ha aumentado la producción agrícola y la eficiencia del uso del agua, el problema de las altas tasas de erosión aún no ha sido mitigado adecuadamente. El estudio de la huella hídrica (HH) revela que en 1 L de aceite de oliva español más del 99,5% de la HH está relacionado con la producción de la aceituna, mientras que menos del 0,5% se debe a otros componentes, es decir, a la botella, tapón y etiqueta. Durante el período estudiado, la HH verde en secano y en regadío representa alrededor del 72% y 12%, respectivamente, del total de la HH. Las HHs azul y gris representan 6% y 10%, respectivamente. La producción de aceitunas se concentra en regiones con una HH menor por unidad de producto. La producción de aceite de oliva ha aumentado su productividad del agua durante 1997-2008, incentivado por los crecientes precios del aceite, como también lo ha hecho la cantidad de exportaciones de agua virtual. De hecho, las mayores zonas productoras presentan una eficiencia alta del uso y de productividad del agua, así como un menor potencial de contaminación por nitratos. Pero en estas zonas se ve a la vez reflejado un aumento de presión sobre los recursos hídricos locales. El aumento de extracciones de agua subterránea relacionadas con las exportaciones de aceite de oliva podría añadir una mayor presión a la ya estresada cuenca del Guadalquivir, mostrando la necesidad de equilibrar las fuerzas del mercado con los recursos locales disponibles. Los cambios de uso de suelo y cobertura vegetal juegan un papel importante en el balance del agua de la cuenca alta del Turia, pero no son el principal motor que sustenta la reducción observada de caudal. El aumento de la temperatura es el principal factor que explica las mayores tasas de evapotranspiración y la reducción de caudales. Sin embargo, los cambios de uso de suelo y el cambio climático han tenido un efecto compensatorio en la respuesta hidrológica. Por un lado, el caudal se ha visto afectado negativamente por el aumento de la temperatura, mientras que los cambios de uso de suelo y cobertura vegetal han compensado positivamente con una reducción de las tasas de evapotranspiración, gracias a los procesos de disminución de la densidad de matorral y de degradación forestal. El estudio proporciona una visión que fortalece la interdisciplinariedad entre la planificación hidrológica y territorial, destacando la necesidad de incluir las implicaciones de los cambios de uso de suelo y cobertura vegetal en futuros planes hidrológicos. Estos hallazgos son valiosos para la gestión de la cuenca del río Turia, y el enfoque empleado es útil para la determinación del peso de los cambios de uso de suelo y cobertura vegetal en la respuesta hidrológica en otras regiones. ABSTRACT Achieving a more efficient and equitable water management at catchment scale does not only rely on the water resource itself, but also on other policies and scientific knowledge. There is a growing consensus that, in addition to consideration of changing climate conditions, integration with research areas such as agronomy, land use planning and economics and political science is required to meet sustainably the societal and environmental water demands. The Common Agricultural Policy (CAP) is a main driver for trends in rural landscapes and agricultural systems, but environmental deterioration is now a principal concern. One of the most relevant changes has occurred with the expansion and intensification of olive orchards in Spain, taking place mainly with new irrigated areas or with the conversion from rainfed to irrigated systems. Moreover, changing climate conditions might exert a major role on water yield trends, but it remains unclear the role that ongoing land use and land cover changes (LULCC) might have on observed river flow trends. This thesis aims to improve the understanding of the effects of agricultural production, policies and LULCC on water quality conditions, hydrological response and human water appropriation. Firstly, the study determines the existing trends for nitrates and suspended solids in the Guadalquivir river basin’s surface waters (south Spain) during the period from 1998 to 2009. From a policy perspective, the research tries to assess with panel data analysis the main drivers, including the 2003 CAP reform, which are having an influence on both water quality indicators. Secondly, water appropriation and nitrate pollution level originating from the production of olive oil in Spain is determined with a water footprint (WF) assessment, considering a spatial temporal variability across the Spanish provinces and from 1997 to 2008 years. Finally, the thesis analyzes the effects of the LULCC on the observed negative trends over the period 1973-2008 in the Upper Turia basin, headwaters of the Júcar river demarcation (east Spain), with ecohydrological modeling. In the Guadalquivir river basin about 20% of monitoring stations show significant trends, linear or quadratic, for each water quality indicator. Most significant trends of nitrates are augmenting than decreasing, and most significant quadratic terms of both indicators exhibit U-shaped patterns. The panel data models show that the most important drivers that are worsening nitrates and suspended solids in the basin are biomass intensification and exports of both water quality indicators from upland regions. In regions that agricultural abandonment and/or de-intensification have taken place the water quality conditions have improved. For nitrates, the decoupling of agricultural subsidies and the reduction of the amount of subsidies to irrigated land underlie the observed reduction of nitrates concentration. Measures of irrigation modernization and establishment of vulnerable zones to nitrates ameliorate the concentration of nitrates in subbasins showing an increasing trend. However, the effect of nitrates load from upland areas, intensification of biomass and crop prices present a greater weight leading to the final increasing trend in this subbasins group, where annual crops dominate. For suspended solids, there is no clear evidence that decoupling process have influenced negatively or positively. Nevertheless, greater values of subsidies still linked to production, particularly in irrigated regions, lead to increasing erosion rates. Although agricultural production has augmented in the basin and water efficiency in the agricultural sector has improved, the issue of high erosion rates has not yet been properly faced. The water footprint (WF) assessment reveals that for 1 L Spanish olive oil more than 99.5% of the WF is related to the olive fruit production, whereas less than 0.5% is due to other components i.e. bottle, cap and label. Over the studied period, the green WF in rainfed and irrigated systems represents about 72% and 12%, respectively, of the total WF. Blue and grey WFs represent 6% and 10%, respectively. The olive production is concentrated in regions with the smallest WF per unit of product. The olive oil production has increased its apparent water productivity from 1997 to 2008 incentivized by growing trade prices, but also did the amount of virtual water exports. In fact, the largest producing areas present high water use efficiency per product and apparent water productivity as well as less nitrates pollution potential, but this enhances the pressure on the available water resources. Increasing groundwater abstractions related to olive oil exports may add further pressure to the already stressed Guadalquivir basin. This shows the need to balance the market forces with the available local resources. Concerning the effects of LULCC on the Upper Turia basin’s streamflow, LULCC play a significant role on the water balance, but it is not the main driver underpinning the observed reduction on Turia's streamflow. Increasing mean temperature is the main factor supporting larger evapotranspiration rates and streamflow reduction. In fact, LULCC and climate change have had an offsetting effect on the streamflow generation during the study period. While streamflow has been negatively affected by increasing temperature, ongoing LULCC have positively compensated with reduced evapotranspiration rates, thanks to mainly shrubland clearing and forest degradation processes. The research provides insight for strengthening the interdisciplinarity between hydrological and spatial planning, highlighting the need to include the implications of LULCC in future hydrological plans. These findings are valuable for the management of the Turia river basin, as well as a useful approach for the determination of the weight of LULCC on the hydrological response in other regions.
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According to the PMBOK (Project Management Body of Knowledge), project management is “the application of knowledge, skills, tools, and techniques to project activities to meet the project requirements” [1]. Project Management has proven to be one of the most important disciplines at the moment of determining the success of any project [2][3][4]. Given that many of the activities covered by this discipline can be said that are “horizontal” for any kind of domain, the importance of acknowledge the concepts and practices becomes even more obvious. The specific case of the projects that fall in the domain of Software Engineering are not the exception about the great influence of Project Management for their success. The critical role that this discipline plays in the industry has come to numbers. A report by McKinsey & Co [4] shows that the establishment of programs for the teaching of critical skills of project management can improve the performance of the project in time and costs. As an example of the above, the reports exposes: “One defense organization used these programs to train several waves of project managers and leaders who together administered a portfolio of more than 1,000 capital projects ranging in Project management size from $100,000 to $500 million. Managers who successfully completed the training were able to cut costs on most projects by between 20 and 35 percent. Over time, the organization expects savings of about 15 percent of its entire baseline spending”. In a white paper by the PMI (Project Management Institute) about the value of project management [5], it is stated that: “Leading organizations across sectors and geographic borders have been steadily embracing project management as a way to control spending and improve project results”. According to the research made by the PMI for the paper, after the economical crisis “Executives discovered that adhering to project management methods and strategies reduced risks, cut costs and improved success rates—all vital to surviving the economic crisis”. In every elite company, a proper execution of the project management discipline has become a must. Several members of the software industry have putted effort into achieving ways of assuring high quality results from projects; many standards, best practices, methodologies and other resources have been produced by experts from different fields of expertise. In the industry and the academic community, there is a continuous research on how to teach better software engineering together with project management [4][6]. For the general practices of Project Management the PMI produced a guide of the required knowledge that any project manager should have in their toolbox to lead any kind of project, this guide is called the PMBOK. On the side of best practices 10 and required knowledge for the Software Engineering discipline, the IEEE (Institute of Electrical and Electronics Engineers) developed the SWEBOK (Software Engineering Body of Knowledge) in collaboration with software industry experts and academic researchers, introducing into the guide many of the needed knowledge for a 5-year expertise software engineer [7]. The SWEBOK also covers management from the perspective of a software project. This thesis is developed to provide guidance to practitioners and members of the academic community about project management applied to software engineering. The way used in this thesis to get useful information for practitioners is to take an industry-approved guide for software engineering professionals such as the SWEBOK, and compare the content to what is found in the PMBOK. After comparing the contents of the SWEBOK and the PMBOK, what is found missing in the SWEBOK is used to give recommendations on how to enrich project management skills for a software engineering professional. Recommendations for members of the academic community on the other hand, are given taking into account the GSwE2009 (Graduated Software Engineering 2009) standard [8]. GSwE2009 is often used as a main reference for software engineering master programs [9]. The standard is mostly based on the content of the SWEBOK, plus some contents that are considered to reinforce the education of software engineering. Given the similarities between the SWEBOK and the GSwE2009, the results of comparing SWEBOK and PMBOK are also considered valid to enrich what the GSwE2009 proposes. So in the end the recommendations for practitioners end up being also useful for the academic community and their strategies to teach project management in the context of software engineering.
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El objetivo de esta Tesis es crear un Modelo de Diseño Orientado a Marcos que, intermedio entre el Mundo Externo y el Modelo Interno del Mundo que supone el sistema ímplementado, disminuya la pérdida de conocimiento que se produce al formalizar la realidad en Bases de Conocimientos. El modelo disminuye la pérdida de conocimiento al formalizar Bases de Conocimiento, acercando el formalismo de Marcos al Mundo Externo, porque: 1. Crea una base teórica que uniformiza el concepto de Marco en el plano de la Formalización, estableciendo un conjunto de restricciones sintácticas y semánticas que impedirán, al Ingeniero del Conocimiento (IC) cuando formaliza, definir elementos no permitidos o el uso indebido de ellos. 2. Se incrementa la expresividad del formalismo al asociar a cada una de las propiedades de un marco clase un parámetro adicional que simboliza la representatividad de la propiedad en el concepto. Este parámetro, y las técnicas de inferencia que trabajan con él, permitirán al IC introducir en el Modelo Formalizado conocimiento que antes no introducía al construir la base de conocimientos y que, sin embargo, sí existía en la realidad. 3. Se propone una técnica de equiparación que trabaja con el conocimiento incierto presente en el dominio. Esta técnica de equiparación, utiliza la representatividad de las propiedades en los marcos clase y el grado de certeza de las propiedades de las entidades para calcular el valor de equiparación y, así, determinar en qué medida los marcos clase seleccionados son consistentes con la descripción de la situación actual dada por una entidad. 4. Proporciona nuevas técnicas de inferencia basadas en la transferencia de propiedades y modifica las ya existentes. Las transferencias de propiedades realizadas sobre relaciones "ad hoc" definidas por el IC al construir el sistema, es una nueva técnica de inferencia independiente y complementaria a la transferencia de propiedades llamada tradicionalmente Herencia (cesión de propiedades entre padres e hijos). A esta nueva técnica, se le ha llamado Donación, es decir, cesión de propiedades entre marcos sin parentesco. Como aportación práctica, se ha construido un entorno de construcción de Sistemas Basados en el Conocimiento formalizados en Marcos, donde se han introducido todos los nuevos conceptos del Modelo Teórico de la Tesis. Se trata de una cierta anidación. Es decir, son marcos que permiten formalizar cualquier SBC en marcos. El entorno permitirá al IC formalizar bases de conocimientos automáticamente y éste podrá validar el conocimiento del dominio en la fase de formalización en lugar de tener que esperar a que la BC esté implementada. Todo ello lleva a describir el Modelo de Diseño Orientado a Marcos como un puente que aproxima y comunica el Mundo Externo con el Modelo Interno asociado a la realidad e implementado en una computadora, disminuyendo así las diversas pérdidas de conocimiento que si bien no ocurren simultáneamente al construir Sistemas Basados en el Conocimiento, sí coexisten en él.---ABSTRACT---The goal of this thesis is to créate a Frame-Orlented Deslgn Model that, bridging the Outside World and the implemented system's Internal Model of the World, reduces the amount of knowledge lost when reality is formalized in Knowledge Bases (KB). The model diminishes the loss of knowledge when formalizing a KB and brings the Frame-formalized Model closer to the Outside World because: 1. It creates a theory that standardizes the concept of trame at the formalization level to establish a set of syntactic and semantic constraints that will prevent the Knowledge Engineer (KE) from defining forbidden elements or their undue use in the formalization process. 2. The formalism's expressiveness is increased by associating an additional parameter to each of the properties of a class frame to symbolize the representativeness of the concept property. This parameter and the related inference techniques will allow the KE to enter knowledge into the Formalized Model that actually existed but that was not used previously when building the KB. 3. The proposed technique involves matching and works with uncertain knowledge present in the domain. This matching technique takes the representativeness of the properties in the class frame and the degree of certainty of the properties of the entities to calcúlate the matching valué and thus determine to what extent the class frames selected are consistent with the description of the present situation given by an entity. 4. It offers new inference techniques based on property transfer and alters existing ones. Property transfer on ad hoc relations defined by the KE when building a system is a new inference technique independent of and complementary to property transfer traditionally termed Inheritance (transfer of properties between parents and children). This new technique has been callad Donation (transfer of properties between trames without relationships). 5. It improves control of the procedural knowledge defined in the trames by introducing OO concepta. A frame-formalized KBS building environment has been constructed, incorporating all the new concepts of the theoretical model set out in the thesis. There is some embedding, that is, they are trames that provide for any KBS to be formalizad in trames. The environment will enable the KE to formaliza KB automatically, and he will be able to valídate the domain knowledge in the formalization stage instead of havíng to wait until the KB has been implemented. This is a description of the Frame-oriented Design Model, a bridge that brings closer and communicates the Outside World with the Interna! Model associated to reality and implemented on a computar, thus reducing the different losses in knowledge that, though they do not occur simultaneosly when building a Knowledge-based System, coexist within it.
Resumo:
This study proposes a marketing approach to service recovery (SR) models in order to help to explain what factors affect cumulative satisfaction, loyalty and word-of-mouth following complaint behavior. The model has its base on the definition of perceived justice and its influence on satisfaction with service recovery (SSR) and on emotions (positive and negative). Trust acts as a central construct in the model, receiving influence from the affective and cognitive aspect and mediating the relationship between SSR and cumulative satisfaction and between positive/negative emotions and loyalty. The sample for this study consists of 303 Spanish B2C-EC users who made a complaint after an electronic transaction. Results from the analysis show the influence of perceived justice ?mainly interactional justice and procedural justice? on SSR, and the relevance of positive emotions as a key factor in SSR processes, in contrast to the major role which negative emotions have traditionally played in these models. Furthermore, trust mediates the relation between SSR and cumulative satisfaction, and is the factor which has a higher influence on loyalty, whilst cumulative satisfaction becomes the more relevant factor affecting WOM.