MonetDB: Two Decades of Research in Column-oriented Database Architectures

MonetDB is a state-of-the-art open-source column-store database management system targeting applications in need for analytics over large collections of data. MonetDB is actively used nowadays in health care, in telecommunications as well as in scientific databases and in data management research, accumulating on average more than 10,000 downloads on a monthly basis. This paper gives a brief overview of the MonetDB technology as it developed over the past two decades and the main research highlights which drive the current MonetDB design and form the basis for its future evolution

An Empirical Comparison of Reuse in Embedded and Nonembedded Systems

High-quality software, delivered on time and budget, constitutes a critical part of most products and services in modern society. Our government has invested billions of dollars to develop software assets, often to redevelop the same capability many times. Recognizing the waste involved in redeveloping these assets, in 1992 the Department of Defense issued the Software Reuse Initiative. The vision of the Software Reuse Initiative was To drive the DoD software community from its current re-invent the software cycle to a process-driven, domain-specific, architecture-centric, library-based way of constructing software.\u27\u27 Twenty years after issuing this initiative, there is evidence of this vision beginning to be realized in nonembedded systems. However, virtually every large embedded system undertaken has incurred large cost and schedule overruns. Investigations into the root cause of these overruns implicates reuse. Why are we seeing improvements in the outcomes of these large scale nonembedded systems and worse outcomes in embedded systems? This question is the foundation for this research. The experiences of the Aerospace industry have led to a number of questions about reuse and how the industry is employing reuse in embedded systems. For example, does reuse in embedded systems yield the same outcomes as in nonembedded systems? Are the outcomes positive? If the outcomes are different, it may indicate that embedded systems should not use data from nonembedded systems for estimation. Are embedded systems using the same development approaches as nonembedded systems? Does the development approach make a difference? If embedded systems develop software differently from nonembedded systems, it may mean that the same processes do not apply to both types of systems. What about the reuse of different artifacts? Perhaps there are certain artifacts that, when reused, contribute more or are more difficult to use in embedded systems. Finally, what are the success factors and obstacles to reuse? Are they the same in embedded systems as in nonembedded systems? The research in this dissertation is comprised of a series of empirical studies using professionals in the aerospace and defense industry as its subjects. The main focus has been to investigate the reuse practices of embedded systems professionals and nonembedded systems professionals and compare the methods and artifacts used against the outcomes. The research has followed a combined qualitative and quantitative design approach. The qualitative data were collected by surveying software and systems engineers, interviewing senior developers, and reading numerous documents and other studies. Quantitative data were derived from converting survey and interview respondents\u27 answers into coding that could be counted and measured. From the search of existing empirical literature, we learned that reuse in embedded systems are in fact significantly different from nonembedded systems, particularly in effort in model based development approach and quality where the development approach was not specified. The questionnaire showed differences in the development approach used in embedded projects from nonembedded projects, in particular, embedded systems were significantly more likely to use a heritage/legacy development approach. There was also a difference in the artifacts used, with embedded systems more likely to reuse hardware, test products, and test clusters. Nearly all the projects reported using code, but the questionnaire showed that the reuse of code brought mixed results. One of the differences expressed by the respondents to the questionnaire was the difficulty in reuse of code for embedded systems when the platform changed. The semistructured interviews were performed to tell us why the phenomena in the review of literature and the questionnaire were observed. We asked respected industry professionals, such as senior fellows, fellows and distinguished members of technical staff, about their experiences with reuse. We learned that many embedded systems used heritage/legacy development approaches because their systems had been around for many years, before models and modeling tools became available. We learned that reuse of code is beneficial primarily when the code does not require modification, but, especially in embedded systems, once it has to be changed, reuse of code yields few benefits. Finally, while platform independence is a goal for many in nonembedded systems, it is certainly not a goal for the embedded systems professionals and in many cases it is a detriment. However, both embedded and nonembedded systems professionals endorsed the idea of platform standardization. Finally, we conclude that while reuse in embedded systems and nonembedded systems is different today, they are converging. As heritage embedded systems are phased out, models become more robust and platforms are standardized, reuse in embedded systems will become more like nonembedded systems

Spider web anthropologies: ecologies, infrastructures, entanglements

Ecologies, infrastructures, entanglements. Anthropology and STS have recently found some unsuspected common groundings in the relational, emergent and self-organizational affordances of these three conceptual systems. Vibrant yet fragile, interactive and responsive whilst simultaneously resilient and solicitous, the earthy and muddled and tenacious engagements afforded by ‘ecologies’, ‘infrastructures’ and ‘entanglements’ have brought new sources of analytical vitality and valence to social theory. These are languages of description that conjure worlds of material and biotic interdependencies, human and non-human agencies weaving themselves into and around filaments of energy, matter, history and decay. Worlds that hold on; worlds that creep up. Spider worlds and spider webs calling for spider web anthropologies. In this chapter I want to introduce the figure of the spider web as a heuristic to helps us think our current predicament of expulsion, ruin and precarity. The spider web, I want to suggest, offers an apposite metaphor for a world that holds itself in precarious balance, that tenses itself with violence and catastrophe but also grace and beauty, and that calls out and silhouettes promissory worlds of entanglements. However, what draws me to the metaphoric seduction of the spider web, I must add, is one specific trait: its semblance and vocation as a trap. Spider webs are traps. It is their materiality as traps, their condition as material and epistemic interfaces between worlds, that helps us ‘capture’ new openings for the work of imagination and description today. I am interested in the work that traps can do for description, in the trap as a method for description. The spider web offers a beautiful example of how this method works: the spider web entangles the worlds of prey and predator and in so doing outlines and crystallizes the infrastructure of their ecologies. The spider-web-trap is an ecology, but it is also an entanglement, and it is also an infrastructure. I shall return to each one of these registers in some more detail shortly. The method of description that the spider-web-trap sets in motion is a specific type of ‘recursive’ operation: think of the spider’s spinning of the web, eating part of it daily to recuperate some of the energy expended in spinning. The operation of recursion works therefore as a source environment for future descriptions and an environmental palette itself. We may think of it as a technique of ‘double environmentalisation’: weaving worlds into existence at the same time as it re-captures existing worlds. Describing worlds and worldling descriptions. Worlds that hold on, worlds that creep up.Peer reviewe

Reutilización de soluciones arquitectónicas empleando razonamiento basado en casos

El diseño de arquitecturas de software es una actividad creativa y compleja realizada principalmente por arquitectos de software. Consiste de una colección de decisiones que generalmente están influenciadas por la experiencia y los conocimientos de los arquitectos involucrados. El razonamiento basado en casos es una técnica de inteligencia artificial que se emplea en este trabajo para brindar soporte al diseño, recordando a los diseñadores experiencias previas que pueden ayudar en nuevas situaciones, mediante la reutilización de soluciones arquitectónicas empleadas con anterioridad. El objetivo principal es proveer al arquitecto de un conjunto de soluciones que podrían ser aplicadas como una propuesta inicial para diseñar la arquitectura del sistema, que luego deberá ir extendiendo hasta incluir todos los requerimientos. Se describe también una herramienta desarrollada para dar soporte a la técnica planteada y un caso de estudio en dónde queda plasmada la propuesta.Sociedad Argentina de Informática e Investigación Operativ

THE ROLE OF UNDERLYING MECHANISMS IN ACHIEVING CONSISTENT HYBRID COMBINATIONS OF COMPETITIVE ADVANTAGES

This thesis takes a step beyond the current discussion on hybrid competitive strategies (HS) by identifying the underlying mechanisms and common elements of successful hybrid strategies. Reviewing empirical and theoretical literature revealed a significant gap in this respect. Therefore, the activity-based view of strategy is introduced to the discussion on HS. In a first step, four consistent and sustainable HS concepts are developed providing the basis for deriving specific HS models. A second step identifies commonalities among these HS types and theoretically derives a synthesized, common HS model. Thirdly, the critical realist stance was selected for answering this thesis’ research questions addressing consistent HS concepts, implementations, common activities achieving external and internal fit, as well as common capabilities and resources supporting these activities. In a case study approach, semi-structured, open ended interviews combining appreciative and laddering methods are conducted with twelve interviewees from five firms. The separate analysis of ladder elements and ladders allowed distinguishing constitutional from relational elements. Based on this, fourth, an empirically revised research construct is substantiated. This research finds HS firms applying intended and consistent, but mixed strategy concepts based on generating high customer benefits through combining competitive weapons of differentiation and price or total customer cost. Moreover, HS concepts centre on three strategic building blocks: customer centricity, fulfilment of customer needs and employee orientation. Additionally, the research indicates that firms apply activities primarily for achieving fit. While all firms combine both views, no activities are directed to both fit types simultaneously. Activities deploy capabilities and resources in general on two adaptive and two absorptive mechanisms. Several practical implications derive from this thesis. First, firms can apply the synthesized model as a kind of ‘blueprint’ providing orientation for how to combine competitive advantages. Second, policy makers can apply the outcomes as principles steering firms or industries to ‘higher’ levels of performance. Last, firm managers can adapt their own as well as their firm’s behaviour accordingly

Implementing OBDA for an end-user query answering service on an educational ontology

In the age where productivity of society is no longer defined by the amount of information generated, but from the quality and assertiveness that a set of data may potentially hold, the right questions to do depends on the semantic awareness capability that an information system could evolve into. To address this challenge, in the last decade, exhaustive research has been done in the Ontology Based Data Access (OBDA) paradigm. A conspectus of the most promising technologies with data integration capabilities and the foundations where they rely are documented in this memory as a point of reference for choosing tools that supports the incorporation of a conceptual model under a OBDA method. The present study provides a practical approach for implementing an ontology based data access service, to educational context users of a Learning Analytics initiative, by means of allowing them to formulate intuitive enquiries with a familiar domain terminology on top of a Learning Management System. The ontology used was completely transformed to semantic linked data standards and some data mappings for testing were included. Semantic Linked Data technologies exposed in this document may exert modernization to environments in which object oriented and relational paradigms may propagate heterogeneous and contradictory requirements. Finally, to validate the implementation, a set of queries were constructed emulating the most relevant dynamics of the model regarding the dataset nature

Engineering context-aware systems and applications: a survey

Context-awareness is an essential component of systems developed in areas like Intelligent Environments, Pervasive & Ubiquitous Computing and Ambient Intelligence. In these emerging fields, there is a need for computerized systems to have a higher understanding of the situations in which to provide services or functionalities, to adapt accordingly. The literature shows that researchers modify existing engineering methods in order to better fit the needs of context-aware computing. These efforts are typically disconnected from each other and generally focus on solving specific development issues. We encourage the creation of a more holistic and unified engineering process that is tailored for the demands of these systems. For this purpose, we study the state-of-the-art in the development of context-aware systems, focusing on: A) Methodologies for developing context-aware systems, analyzing the reasons behind their lack of adoption and features that the community wish they can use; B) Context aware system engineering challenges and techniques applied during the most common development stages; C) Context aware systems conceptualization

Engineering context-aware systems and applications:A survey

Context-awareness is an essential component of systems developed in areas like Intelligent Environments, Pervasive & Ubiquitous Computing and Ambient Intelligence. In these emerging fields, there is a need for computerized systems to have a higher understanding of the situations in which to provide services or functionalities, to adapt accordingly. The literature shows that researchers modify existing engineering methods in order to better fit the needs of context-aware computing. These efforts are typically disconnected from each other and generally focus on solving specific development issues. We encourage the creation of a more holistic and unified engineering process that is tailored for the demands of these systems. For this purpose, we study the state-of-the-art in the development of context-aware systems, focusing on: (A) Methodologies for developing context-aware systems, analyzing the reasons behind their lack of adoption and features that the community wish they can use; (B) Context-aware system engineering challenges and techniques applied during the most common development stages; (C) Context-aware systems conceptualization

Representación y razonamiento sobre las decisiones de diseño de arquitectura de software

El objetivo general de la Tesis está directamente vinculado a brindar soporte al arquitecto de software durante el diseño arquitectónico. Partiendo de la hipótesis de que los arquitectos de software reutilizan soluciones conocidas en nuevos diseños, se identifica la necesidad de contar con una herramienta, tanto conceptual como computacional, que pueda colaborar con los arquitectos de software en dos aspectos: • uno individual, que se encuentra relacionado con facilitar a los arquitectos la recuperación de experiencias pasadas propias, haciéndolas accesibles de manera de que puedan mapearlas con los problemas actuales para dar solución al diseño de un sistema; • uno grupal, vinculado con facilitar a los arquitectos la recuperación de experiencias pasadas de otros arquitectos, haciéndolas accesibles de manera de que puedan mapearlas con los problemas actuales para dar solución al diseño de un sistema.Eje: Tesis Doctorales. Tesis presentada por la autora en 2015 para la obtención del título de Doctor en Ingeniería, mención Sistemas de Información, con la dirección de Horacio Leone y Silvio Gonnet.Red de Universidades con Carreras en Informática (RedUNCI

Representación y razonamiento sobre las decisiones de diseño de arquitectura de software

El objetivo general de la Tesis está directamente vinculado a brindar soporte al arquitecto de software durante el diseño arquitectónico. Partiendo de la hipótesis de que los arquitectos de software reutilizan soluciones conocidas en nuevos diseños, se identifica la necesidad de contar con una herramienta, tanto conceptual como computacional, que pueda colaborar con los arquitectos de software en dos aspectos: • uno individual, que se encuentra relacionado con facilitar a los arquitectos la recuperación de experiencias pasadas propias, haciéndolas accesibles de manera de que puedan mapearlas con los problemas actuales para dar solución al diseño de un sistema; • uno grupal, vinculado con facilitar a los arquitectos la recuperación de experiencias pasadas de otros arquitectos, haciéndolas accesibles de manera de que puedan mapearlas con los problemas actuales para dar solución al diseño de un sistema.Eje: Tesis Doctorales. Tesis presentada por la autora en 2015 para la obtención del título de Doctor en Ingeniería, mención Sistemas de Información, con la dirección de Horacio Leone y Silvio Gonnet.Red de Universidades con Carreras en Informática (RedUNCI