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Mostrando recursos 1 - 20 de 144,829

1. Stochastic Reconstruction of Loading Histories from a Rainflow Matrix - Klaus Dreßler; Michael Hack; Wilhelm Krüger
This paper is devoted to the mathematical description of the solution of the so-called rainflow reconstruction problem, i.e. the problem of constructing a time series with an a priori given rainflow matrix. The algorithm we present is mathematically exact in the sense that no approximations or heuristics are involved. Furthermore it generates an uniform distribution of all possible reconstructions and thus an optimal randomization of the reconstructed series. The algorithm is a genuine on--line scheme. It is easy adjustable to all variants of rainflow such as symmetric and asymmetric versions and different residue techniques.

2. Decay of correlations for non Hölderian dynamics. A coupling approach - Xavier Bressaud; Antonio Galves
: We present an upper bound on the mixing rate of the equilibrium state of a dynamical system defined by the one-sided shift and a non Holder potential of summable variations. The bound follows from an estimation of the relaxation speed of chains with complete connections with summable decay, which is obtained via a explicit coupling between pairs of chains with different histories. Keywords: dynamical systems, non-Holder dynamics, mixing rate, chains with complete connections, relaxation speed, coupling methods AMS subject classification: 58F11, 60G10 Work done within the Projeto Tem'atico "Fenomenos Cr'iticos em Processos Evolutivos e Sistemas em Equil'ibrio", supported by...

3. A Geometric Framework for Specifying Spatiotemporal Objects - Jan Chomicki; Peter Z. Revesz
We present a framework for specifying spatiotemporal objects using spatial and temporal objects, and a geometric transformation. We define a number of classes of spatiotemporal objects and study their closure properties. 1 Introduction Many natural or man-made phenomena have both a spatial and a temporal extent. Consider for example, a forest fire or property histories in a city. To store information about such phenomena in a database one needs appropriate data modeling constructs. We claim that a new concept, spatiotemporal object, is necessary. In this paper, we introduce a very general framework for specifying spatiotemporal objects. To define a spatiotemporal...

4. Open-loop Stable Control of Running Robots - A Numerical Method for Studying Stability in the Context of Optimal Control Problems - K. D. Mombaur; H. G. Bock; J. P. Schlöder; M. J. Winckler; R. W. Longman
An open-loop controlled robot must have strong stability properties. This paper presents a numerical method for studying the stability of robots in the context of optimal control problems. Parameter studies for a one-legged hopping robot are performed. 1 Introduction Most running robots use sensor-based feedback to actively control the stability of their motion. Perturbations of the desired position histories are detected and appropriate counteractions are computed and performed. In the case of complex robot congurations this task can be too compute-intensive to be handled in real time. It has been shown that it is also possible to construct legged monopods...

5. , George Lake - Ben Moore; Thomas Quinn Joachim; Joachim Stadel
We follow the evolution of disk galaxies within a cluster that forms hierarchically in a cold dark matter N-body simulation. At a redshift z = 0:5 we select several dark matter halos that have quiet merger histories and are about to enter the newly forming cluster environment. The halos are replaced with equilibrium high resolution model spirals that are constructed to represent examples of low surface brightness (LSB) and high surface brightness (HSB) galaxies. Varying the disk and halo structural parameters reveals that the response of a spiral galaxy to tidal encounters depends primarily on the potential depth of the...

6. Using Relations on Streams to Solve the RPC-Memory Specification Problem - Ketil Stølen
. We employ a specification and refinement technique based on streams to solve the RPC-memory specification problem. Streams are used to represent the communication histories of channels. We distinguish between input and output streams. Each input stream represents the communication history of an input channel; each output stream represents the communication history of an output channel. Specifications are relations between input and output streams. These relations are expressed as logical formulas. Composition corresponds to logical conjunction. We distinguish between time-independent and timedependent specifications. A time-independent specification is based on untimed streams; a time-dependent specification employs timed streams. Timed streams are...

7. Real-Time Monitoring of Dense Continuous Data - Andrej Semrl
: We've implemented a monitoring system that assists a perfusionist during open-heart procedures. The monitoring system supports the perfusionist by performing intelligent monitoring, including state recognition and prediction, adaptive alarming system, and data visualization supported by audio feedback. The system performs in an on-line, real-time mode in the dataintensive environments of operating rooms. The system is an open-loop system, where all interventions and decisions are made by perfusionist. For efficient implementation of such a system, adequate knowledge representation must be chosen. By extending the semantics of generalized discrimination trees with frame-like structures, we've been able to integrate medical primitives, such...

8. A Case Study in Knowledge Acquisition for Insurance Risk Assessment using a KDD Methodology - Graham Williams; Zhexue Huang
We describe some initial experiences in dealing with the task of acquiring knowledge where a very large collection of case histories is available. A Knowledge Discovery in Databases (KDD) approach is taken. KDD is the process of extracting novel information and knowledge from large databases, consisting of many interacting stages performing specific data manipulation and transformation operations with an information flow from one stage onto the next (and usually with feedback into previous stages). We characterise our experiences of this process for the task of acquiring knowledge for the domain of motor vehicle insurance premium setting for NRMA Insurance Limited....

9. A Self-Scaling and Self-Configuring Benchmark for Web Servers - Stephen Manley, et al.
... In this paper, we present a self-configuring, scalable benchmark, that generates a server benchmark load based on actual server loads. In contrast to other web benchmarks, our benchmark characterizes request latency instead of focusing exclusively on throughput sensitive metrics. We present our new benchmark, hbench:Web, and demonstrate how it accurately captures the load observed by an actual server. We then go on to show how it can be used to assess how continued growth or changes in the workload will affect future performance. Using existing log histories, we show that these predictions are sufficiently realistic to provide insight into...

10. Integration of Case Studies on Global Change by Means of Artificial Intelligence - Gerhard Petschel-Held And; Gerhard Petschel-held; Matthias K. B. Lüdeke
We present a novel methodology to integrate qualitative knowledge from different case studies on Global Change related issues into a single framework. The method is based on the concept of qualitative differential equations (QDEs) which represents a mathematically well-defined approach to investigate classes of ordinary differential equations (ODEs) used in conventional modeling exercises. These classes are defined by common qualitative features, e.g. monotonicity, signs, etc. Using the QSIMAlgorithm it is possible to derive the set of possible solutions of all ODEs in the class. Using this one can formulate a common, qualitatively specified cause-effect scheme valid for all case studies....

11. Building a Stochastic Dynamic Model of Application Use - Peter J. Gorniak; David Poole
Many intelligent user interfaces employ application and user models to determine the user's preferences, goals and likely future actions. Such models require application analysis, adaptation and expansion. Building and maintaining such models adds a substantial amount of time and labour to the application development cycle. We present a system that observes the interface of an unmodified application and records users' interactions with the application. From a history of such observations we build a coarse state space of observed interface states and actions between them. To refine the space, we hypothesize substates based upon the histories that led users to a...

12. Decentralised Process Enactment in a Multi-Perspective Development Environment - Ulf Leonhardt; Jeff Kramer; Bashar Nuseibeh; Anthony Finkelstein
The ViewPoints framework for distributed and concurrent software engineering provides an alternative approach to traditional centralised software development environments. We investigate the use of decentralised process models to drive consistency checking and conflict resolution in this framework. Our process models use pattern matching on local development histories to determine the particular situation (state) of the development process, and employ rules to trigger situationdependent assistance to the user. We describe how communication between such process models facilitates the decentralised management of explicitly defined consistency constraints in the ViewPoints framework.

13. SAZ: SSADM version 4 and Z - Fiona Polack
el is then validated against the scope of the system. The data flow diagram is reworked to function definitions. These, rather than the DFDs, are the specification of system processing. Function definitions are text descriptions of the processing required of the system, and are derived by identifying system events and tracing their effects through the DFD. SSADM advises that the results are referred to client users, who may combine, divide or replicate the functions. The RS also considers the dynamics of each entity, using entity life histories (ELHs). The case studies use the notations suggested (but not mandated) by SSADM...

14. Diagenetic Variations between Upper Cretaceous Outcrop and Deeply Buried Reservoir Chalks of the North Sea Area* By - Morten L. Hjuler; Ida L. Fabricius
In the central North Sea Basin hydrocarbon-bearing chalks are deeply buried (2-3 km) whereas chalks in the rim areas are cropping out in the surrounding countries. The differing diagenetic histories between buried and outcrop chalk result in different rock properties, which are of great importance when simulating reservoir conditions using outcrop chalks as models. In general, deeply buried reservoir chalks show significant overgrowth as witnessed by reshaping of particles together with strengthening of particle contacts. Most outcrop chalks are moderately affected with looser interparticle connections and less altered particle shapes. The non-carbonate mineralogy of outcrop chalks is dominated by quartz,...

15. Anonymous search histories featuring personalized advertisement - balancing privacy with economic interests - Thorben Burghardt; Klemens Böhm; Achim Guttmann; Chris Clifton
Abstract. Search engines are key to finding information on the web. Search presently is free for users – financed by targeted advertisement. Today, the current search terms determine the ad placement. In the near future, search-engine providers will make use of detailed user profiles for better ad placement. This puts user privacy at risk. Anonymizing search histories, which is a solution in principle, gives way to a trade-off between privacy and the usability of the data for ad placement. This paper studies this tradeoff systematically. To this end, we implement an algorithm for the anonymization of search histories which is...

16. To the Editors: - Dextromethorphan Abuse
A wide range of drugs is being abused by teenagers across the world, and over the years, they seem to have made the discovery that they could get "high " by taking over-the-counter medicines containing dextromethorphan (DXM). Cases of recreational use of DXM [1] and its sideeffects [2] have been reported in other countries. The following case histories are presented to emphasise the main clinical features and the management of dextromethorphan abuse among Sri Lankan youths. A 19-year old male, who had been abusing Corex-D for the last four years presented with elevated mood, visual hallucinations and a recent risk...

17. SELECTION OF THE APPROPRIATE METHODOLOGY FOR THE DETERMINISTIC SEISMIC HAZARD ASSESSMENT ON THE TERRITORY OF THE REPUBLIC OF SERBIA - Borko Bulajić; Miodrag Manić
Abstract. This paper presents a discussion regarding the most common approaches to the deterministic seismic hazard analysis, as well as their relation with the probabilistic hazard analysis. Different methodologies for estimation of the strong earthquake ground motion at a site of interest on the territory of the Republic of Serbia are also discussed. When generation of the synthetic ground motion time histories on the territory of the Republic of Serbia is concerned, a method developed by Trifunac and his associates is suggested, having in mind that this approach uses only those input parameters that can be easily and accurately defined...

18. Leading Articles Some reflections on child abuse in Sri Lanka - D G Harendra De Silva
Although child abuse is often denied in the Indian sub-continent, probably one of the oldest recorded histories of child abuse more than 2500 years ago was from the Buddhist story of a boy called Sopaka. Buddha came to his rescue and preached to the child, one of the earliest instances of counselling. The Buddhist scriptures also record the story of Mattakundali, who was severely neglected by a miserly father. Physical abuse Like all countries, Sri Lanka went through a phase of denial and 'acceptance of child abuse as a norm'. 'Ganadevi hella ' an 18th century verse reads as follows:...

19. Apoyo y fortalecimiento a familias para la crianza de niños con discapacidad - Manjarres Carrizalez, Dora
La investigación presentada en este artículo es un estudio interpretativo de tipo cualitativo que realiza el análisis de las historias de vida de 60 familias en cuatro departamentos de Colombia, con el fin de evidenciar dinámicas de crianza de personas con discapacidad y plantear propuestas apoyo y fortalecimiento al núcleo familiar.Como resultado de la investigación se realizó la caracterización del proceso de crianza identificando pautas, creencias, prácticas y se planteó una estructura que visibiliza tres estilos parentales: participativo, autoritario y permisivo. Se determinaron además, demandas de apoyo y fortalezas de las familias durante éste proceso y se plantearon cuatrolíneas de...

20. Estereotipos, discapacidad y pedagogas infantiles en formación de la Corporación Universitaria Iberoamericana - Torres Martínez, Myriam Lucero
Este artículo presenta los resultados de la investigación Estereotipos, discapacidad y Pedagogas infantiles en formación de la Corporación Universitaria Iberoamericana; la investigación tuvo un enfoque cualitativo y carácter descriptivo. El objetivo se centró en identificar los estereotipos construidos por un grupo de 50 estudiantes de laLicenciatura de Pedagogía Infantil en torno a la discapacidad quienes fueron seleccionadas de forma intencional para fines de la investigación. Se aplicaron dos talleres: Taller I la discapacidad desde la imagen y el Taller II discapacidad desde las historia de vida. Los resultados de los estereotipos se centraron más en creencias o imaginarios que en elconocimiento epistemológico y real...

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