742 resultados para implementations
Resumo:
We present a detailed description of the Voronoi Tessellation (VT) cluster finder algorithm in 2+1 dimensions, which improves on past implementations of this technique. The need for cluster finder algorithms able to produce reliable cluster catalogs up to redshift 1 or beyond and down to 10(13.5) solar masses is paramount especially in light of upcoming surveys aiming at cosmological constraints from galaxy cluster number counts. We build the VT in photometric redshift shells and use the two-point correlation function of the galaxies in the field to both determine the density threshold for detection of cluster candidates and to establish their significance. This allows us to detect clusters in a self-consistent way without any assumptions about their astrophysical properties. We apply the VT to mock catalogs which extend to redshift 1.4 reproducing the ACDM cosmology and the clustering properties observed in the Sloan Digital Sky Survey data. An objective estimate of the cluster selection function in terms of the completeness and purity as a function of mass and redshift is as important as having a reliable cluster finder. We measure these quantities by matching the VT cluster catalog with the mock truth table. We show that the VT can produce a cluster catalog with completeness and purity > 80% for the redshift range up to similar to 1 and mass range down to similar to 10(13.5) solar masses.
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Visual representations of isosurfaces are ubiquitous in the scientific and engineering literature. In this paper, we present techniques to assess the behavior of isosurface extraction codes. Where applicable, these techniques allow us to distinguish whether anomalies in isosurface features can be attributed to the underlying physical process or to artifacts from the extraction process. Such scientific scrutiny is at the heart of verifiable visualization - subjecting visualization algorithms to the same verification process that is used in other components of the scientific pipeline. More concretely, we derive formulas for the expected order of accuracy (or convergence rate) of several isosurface features, and compare them to experimentally observed results in the selected codes. This technique is practical: in two cases, it exposed actual problems in implementations. We provide the reader with the range of responses they can expect to encounter with isosurface techniques, both under ""normal operating conditions"" and also under adverse conditions. Armed with this information - the results of the verification process - practitioners can judiciously select the isosurface extraction technique appropriate for their problem of interest, and have confidence in its behavior.
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To plan testing activities, testers face the challenge of determining a strategy, including a test coverage criterion that offers an acceptable compromise between the available resources and test goals. Known theoretical properties of coverage criteria do not always help and, thus, empirical data are needed. The results of an experimental evaluation of several coverage criteria for finite state machines (FSMs) are presented, namely, state and transition coverage; initialisation fault and transition fault coverage. The first two criteria focus on FSM structure, whereas the other two on potential faults in FSM implementations. The authors elaborate a comparison approach that includes random generation of FSM, construction of an adequate test suite and test minimisation for each criterion to ensure that tests are obtained in a uniform way. The last step uses an improved greedy algorithm.
Resumo:
In the paper, we discuss dynamics of two kinds of mechanical systems. Initially, we consider vibro-impact systems which have many implementations in applied mechanics, ranging from drilling machinery and metal cutting processes to gear boxes. Moreover, from the point of view of dynamical systems, vibro-impact systems exhibit a rich variety of phenomena, particularly chaotic motion. In this paper, we review recent works on the dynamics of vibro-impact systems, focusing on chaotic motion and its control. The considered systems are a gear-rattling model and a smart damper to suppress chaotic motion. Furthermore, we investigate systems with non-ideal energy source, represented by a limited power supply. As an example of a non-ideal system, we analyse chaotic dynamics of the damped Duffing oscillator coupled to a rotor. Then, we show how to use a tuned liquid damper to control the attractors of this non-ideal oscillator.
Resumo:
In this work, we deal with the problem of packing (orthogonally and without overlapping) identical rectangles in a rectangle. This problem appears in different logistics settings, such as the loading of boxes on pallets, the arrangements of pallets in trucks and the stowing of cargo in ships. We present a recursive partitioning approach combining improved versions of a recursive five-block heuristic and an L-approach for packing rectangles into larger rectangles and L-shaped pieces. The combined approach is able to rapidly find the optimal solutions of all instances of the pallet loading problem sets Cover I and II (more than 50 000 instances). It is also effective for solving the instances of problem set Cover III (almost 100 000 instances) and practical examples of a woodpulp stowage problem, if compared to other methods from the literature. Some theoretical results are also discussed and, based on them, efficient computer implementations are introduced. The computer implementation and the data sets are available for benchmarking purposes. Journal of the Operational Research Society (2010) 61, 306-320. doi: 10.1057/jors.2008.141 Published online 4 February 2009
Resumo:
An all-in-one version of a capacitively coupled contactless conductivity detector is introduced. The absence of moving parts (potentiometers and connectors) makes it compact (6.5 cm(3)) and robust. A local oscillator, working at 1.1 MHz, was optimized to use capillaries of id from 20 to 100 lam. Low noise circuitry and a high-resolution analog-to-digital converter (ADC) (21 bits effective) grant good sensitivities for capillaries and background electrolytes currently used in capillary electrophoresis. The fixed frequency and amplitude of the signal generator is a drawback that is compensated by the steady calibration curves for conductivity. Another advantage is the possibility of determining the inner diameter of a capillary by reading the ADC when air and subsequently water flow through the capillary. The difference of ADC reading may be converted into the inner diameter by a calibration curve. This feature is granted by the 21-bit ADC, which eliminates the necessity of baseline compensation by hardware. In a typical application, the limits of detection based on the 3 sigma criterion (without baseline filtering) were 0.6, 0.4, 0.3, 0.5, 0.6, and 0.8 mu mol/L for K(+), Ba(2+), Ca(2+), Na(+), Mg(2+), and Li(+), respectively, which is comparable to other high-quality implementations of a capacitively coupled contactless conductivity detector.
Resumo:
The aim of the project is to develop a tool for a management system at the advertising agency ofConfetti. The company has during a longer period of time felt a need of introducing a quality and environmentalsystem but have a lack in resources of knowledge, time and money. Their goal is to have aconcrete documentation which describes their quality policy and the function of the activity.The work has been performed by mapping and analyzing the processes of the company according tothe process model with focus on one pilot process. New routines have been developed and documentedin a management system.Confetti would like their management system to fulfil the ISO-standard so that they eventually inthe future can be certified. Therefore a literature study has been done according to management systemsand standards. The project has been directed to fulfil the ISO-standards demands for a qualitymanagement system. It has resulted in the creation of a comprehensible and userfriendly managementsystem which includes a routine model and new routines for the pilot process of PDF-handling. A oneyear-plan has been created to facilitate for the continuos development of the quality management systemat Confetti. The new quality implementations demands investment, why a budget has been calculatedshowing profitability.Confetti has to continue the development of the management system very soon. They ought to createan analyzis of the companys current situation and choose the processes that they themeselves considermost important or easiest to improve. A management system will not operate by it self, it needsmaintenance and development.
Resumo:
Användargränssnittsdesign är en stor del av en webbsidas intryck och förändras snabbt i takt med teknologins utveckling och trender. Men det gäller även att locka rätt användare. Hur lockar en webbsida till sig rätt målgrupp? Målet med rapporten var att analysera målgruppen gamers utifrån hur de upplever det grafiska användargränssnittet på en spelrelaterad webbsida. Rapporten behandlar även översiktitligt om aktuella trender för webbdesign tilltalar gamers. Undersökningen utfördes i två delar. I den första delen undersöktes 20 av de största spelrelaterade webbsidornas användargränssnitt. Under del två genomfördes en enkät och intervjuer med målgruppen gamers. I både enkäten och intervjuerna fick respondenterna ta ställning till olika mockups av en fiktiv webbsida. Det var stor skillnad på vad gamers ansåg vara tilltalande jämfört med hur de analyserade webbsidorna såg ut. Exempelvis var endast 25 % av de analyserade webbsidorna mörka medan 71,9 % av respondenterna föredrog en mörk layout.
Resumo:
The aim of the project is to examine the music salon in Falun as a part of the mining community and in the historical context of European salon culture. A specifc goal is to develop a deeper understanding about the salon when it comes to education and pedagogic ideas. Of a certain interest is Johan Henrik Munktell’s (1804-1861) education travelling (bildningsresor). Inspired by Mendelssohn’s music salon in Berlin and the early salons in Upp-sala he created his own salon in Grycksbo. A letter collection from J.H. Munktell to his father J.J. Munktell in 1828-30 can be considered a unique historical material, which places the salon in Falun in a continental context of culture, education and industrial pretensions. The results have potential to extend the knowledge of Nordic salon culture and how it has infuenced general pedagogy and music education.
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In a global economy, manufacturers mainly compete with cost efficiency of production, as the price of raw materials are similar worldwide. Heavy industry has two big issues to deal with. On the one hand there is lots of data which needs to be analyzed in an effective manner, and on the other hand making big improvements via investments in cooperate structure or new machinery is neither economically nor physically viable. Machine learning offers a promising way for manufacturers to address both these problems as they are in an excellent position to employ learning techniques with their massive resource of historical production data. However, choosing modelling a strategy in this setting is far from trivial and this is the objective of this article. The article investigates characteristics of the most popular classifiers used in industry today. Support Vector Machines, Multilayer Perceptron, Decision Trees, Random Forests, and the meta-algorithms Bagging and Boosting are mainly investigated in this work. Lessons from real-world implementations of these learners are also provided together with future directions when different learners are expected to perform well. The importance of feature selection and relevant selection methods in an industrial setting are further investigated. Performance metrics have also been discussed for the sake of completion.
Resumo:
Architectural description languages (ADLs) are used to specify high-level, compositional view of a software application. ADLs usually come equipped with a rigourous state-transition style semantics, facilitating specification and analysis of distributed and event-based systems. However, enterprise system architectures built upon newer middleware (implementations of Java’s EJB specification, or Microsoft’s COM+/ .NET) require additional expressive power from an ADL. The TrustME ADL is designed to meet this need. In this paper, we describe several aspects of TrustME that facilitate specification and anlysis of middleware-based architectures for the enterprise.
Resumo:
Architecture description languages (ADLs) are used to specify high-level, compositional views of a software application. ADL research focuses on software composed of prefabricated parts, so-called software components. ADLs usually come equipped with rigorous state-transition style semantics, facilitating verification and analysis of specifications. Consequently, ADLs are well suited to configuring distributed and event-based systems. However, additional expressive power is required for the description of enterprise software architectures – in particular, those built upon newer middleware, such as implementations of Java’s EJB specification, or Microsoft’s COM+/.NET. The enterprise requires distributed software solutions that are scalable, business-oriented and mission-critical. We can make progress toward attaining these qualities at various stages of the software development process. In particular, progress at the architectural level can be leveraged through use of an ADL that incorporates trust and dependability analysis. Also, current industry approaches to enterprise development do not address several important architectural design issues. The TrustME ADL is designed to meet these requirements, through combining approaches to software architecture specification with rigorous design-by-contract ideas. In this paper, we focus on several aspects of TrustME that facilitate specification and analysis of middleware-based architectures for trusted enterprise computing systems.
Resumo:
The Object Managment Group’s Meta-Object Facility (MOF) is a semiformal approach to writing models and metamodels (models of models). The MOF was developed to enable systematic model/metamodel interchange and integration. The approach is problematic, unless metamodels are correctly specified: an error in a metamodel specification will propagate throughout instantiating models and final model implementations. An important open question is how to develop provably correct metamodels. This paper outlines a solution to the question, in which the MOF metamodelling approach is formalized within constructive type theory.
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BDI agent languages provide a useful abstraction for complex systems comprised of interactive autonomous entities, but they have been used mostly in the context of single agents with a static plan library of behaviours invoked reactively. These languages provide a theoretically sound basis for agent design but are very limited in providing direct support for autonomy and societal cooperation needed for large scale systems. Some techniques for autonomy and cooperation have been explored in the past in ad hoc implementations, but not incorporated in any agent language. In order to address these shortcomings we extend the well known AgentSpeak(L) BDI agent language to include behaviour generation through planning, declarative goals and motivated goal adoption. We also develop a language-specific multiagent cooperation scheme and, to address potential problems arising from autonomy in a multiagent system, we extend our agents with a mechanism for norm processing leveraging existing theoretical work. These extensions allow for greater autonomy in the resulting systems, enabling them to synthesise new behaviours at runtime and to cooperate in non-scripted patterns.
Resumo:
Esta pesquisa é uma extensão do trabalho de doutorado Studying Configurational Technology Implementation: A Mediation Process, cujo foco de análise foi o processo de mediação nas implementações de ERP. Processo de mediação é o processo através do qual clientes e consultores conjuntamente influenciam as decisões que são feitas sobre como o sistema será configurado. A partir dessa análise, foram identificados alguns padrões no processo de mediação, estabelecendo-se associações entre esses padrões e os resultados da implementação. Nosso estudo busca analisar o processo de implementação de tecnologias configuráveis, mais precisamente ERP Enterprise Resource Planning, sob o mesmo enfoque do trabalho de doutorado descrito acima, mas observando-se empresas brasileiras. Nossos resultados serão comparados aos resultados encontrados nas empresas canadenses, buscando-se identificar diferenças e similaridades e seu impacto nos resultados do projeto. Visamos, dessa maneira, promover um melhor entendimento sobre o processo de implementação de ERP, contribuindo para minimizar o risco de fracasso de tal empreendimento em empresas brasileiras.