1,096 research outputs found
Anthropology as an interdisciplinary field
No full textThe article discusses anthropology as an interdisciplinary field from the author's own research experience.AnthropologySociologySSCI0ARTICLE120-243
JDOS: A Jini Based Distributed Operating System.
No full textJ-DOS provides and integrated JAVA environment for the execution of a program across an interconnected network of heterogeneous computers. The system provides a file system, shared memory and a distributed execution scheme, all of which is transparent to the user. The framework used to provide these service is sufficiently general as to allow the provision of extra services by the user. We describe the client-server execution, remote execution and the shared file system, paying particular attention to the techniques used to distribute threads over many nodes. Distributed Mandelbrot set generation and rendering is used to benchmark and validate the remote execution and load balancing aspects of the system
Stratego/XT 0.17. A Language and Toolset for Program Transformation
No full textPreprint of paper published in: Science of Computer Programming (Elsevier), 72 (1-2), 2008; doi:10.1016/j.scico.2007.11.003 Stratego/XT is a language and toolset for program transformation. The Stratego language provides rewrite rules for expressing basic transformations, programmable rewriting strategies for controlling the application of rules, concrete syntax for expressing the patterns of rules in the syntax of the object language, and dynamic rewrite rules for expressing context-sensitive transformations, thus supporting the development of transformation components at a high level of abstraction. The XT toolset offers a collection of flexible, reusable transformation components, and tools for generating such components from declarative specifications. Complete program transformation systems are composed from these components. This paper gives an overview of Stratego/XT 0.17, including a description of the Stratego language and XT transformation tools; a discussion of the implementation techniques and software engineering process; and a description of applications built with Stratego/XT.Software Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc
XT-ADS sensitivity analysis
No full textThis work has been carried out in the first period (March-June 2010) In which the author Joined the Central Design Team in Mol (B) for the CDT/FASTEF EU FP7 project. Before to start with the deep characterisation foreseen during the WP2 for FASTEF (100 MW LBE cooled reactor, working in both critical and sub-critical modes), a preliminary code tuning has been carried out by adopting the XT-ADS core layout (developed in IP EUROTRANS, EU FP6 project). The tuning deals with the neutronic codes, in particular: ERANOS (deterministic) and MCNPX (Monte Carlo). The main results have been included in the two SCK-CEN calculation notes here reported. The first calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-15) highlights the main differences between the ERANOS and MCNPX models for XT-ADS. Then the ERANOS input has been modified to consider the same assumptions adopted by MCNPX. A further tuning of both models yields, as a whole, a reduction of the MCNPX-ERANOS keff difference (at BoL) from by about 2700 pcm down to 1000 pcm. The second calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-16) summarizes the XT-ADS sensitivity analysis performed by ERANOS ver. 2.1 with two different nuclear data Iibraries: JEFF3.1 and ENDF/BVI.8. The study, carried out by exploiting the basics of standard perturbation theory, points out which nuclides, which cross-section and which range of energy yield the most significant impact on the core reactivity. As in the first note, the ERANOS evaluations (performed in a reference and voided configurations) have been compared with the results obtained with the MCNFX code
Multi-scale space-variant FRep cellular structures
No full textExisting mesh and voxel based modeling methods encounter difficulties when dealing with objects containing cellular structures
on several scale levels and varying their parameters in space. We describe an alternative approach based on using real functions evaluated procedurally at any given point. This allows for modeling fully parameterized, nested and multi-scale cellular
structures with dynamic variations in geometric and cellular properties. The geometry of a base unit cell is defined using Function Representation (FRep) based primitives and operations. The unit cell is then replicated in space using periodic
space mappings such as sawtooth and triangle waves. While being replicated, the unit cell can vary its geometry and topology due
to the use of dynamic parameterization. We illustrate this approach by several examples of microstructure generation within a given volume or
along a given surface. We also outline some methods for direct rendering and fabrication not involving auxiliary mesh and voxel
representations
IBM/XT-based automatic monitoring instrumentation system for eating behavior studies in rats
No full textAn auto-feeding system based on the IBM-XT microcomputer has been designed for use in the anti-obesity research program in the Pharmacology Department at Hoffmann-La Roche Inc. By using this system, experimental rats can be automatically fed, some which have been given anti-obesity drugs and some which have not. The system can also collect data, such as eating times and food intake, which are used for studying the rat\u27s eating behavior.
The system is designed to control thirty six cages with one experimental rat in each cage and it performs three functions:
1 ) To automatically dispense a preset quantity of food, either when the food left in the food cup falls below a minimum value or at a set interval of time.
2 ) To collect ongoing data such as eating frequency, quantity of food in the cups and quantity of food delivered.
3 ) To perform basic data analysis to show the rat\u27s eating patterns and display the data using tables and bar graphs.
The system consists of three sections: an IBM/XT microcomputer, external devices and electronic interface. The external devices of the system are constructed with the specially designed cage assembles, motor driven feeders, photo sensor pairs, position switches and electronic balances. The system is supported by electronic circuits which interface to the IBM-XT microcomputer. The electronic interfaces were designed and built by the author. The system is also equipped with a software package written in Quick Basic (a compiler BASIC) for performing experiments, testing the system and analyzing the collected data
Influence of irradiation distance on the mechanical performances of resin composites polymerized with high-irradiance light curing units
No full textBACKGROUND: The aim of this study was to evaluate the influence of increased irradiation distance on the flexural strength (FS), dentin micro-shear bond strength (μSBS), and the degree of conversion (DC) of bulk-fill flowable, conventional flowable, and packable resin composites. METHODS: The resin composites tested were Surefil® SDR™ (SDR), Filtek Z350 XT Flowable Restorative A2 shade (Z3F), and Filtek Z350 XT Universal Restorative A2 shade (Z3P). Specimens were cured at four irradiation distances (0, 2, 4, and 8 mm) with an Elipar DeepCure-S LED curing light for 20 s. FS tests were performed (n = 15) using bar-shaped specimens (8 mm × 2 mm × 2 mm) of the resin composites. μSBS tests were performed on the occlusal surfaces of extracted third molars from humans that were ground to expose dentin (n = 15). DC was measured by using Raman spectroscopy on the top and bottom surfaces of disk specimens (2-mm thick) (n = 3). To further investigate whether extended irradiation times could compensate for reduced irradiance, additional Z3P specimens were prepared, which were light-cured at 8-mm distances for 40 and 60 s and subjected to FS tests, μSBS tests, and Raman spectroscopy. Both two-way and one-way ANOVA were used for statistical analyses. RESULTS: Both FS and DC of Z3P specimens cured at an 8-mm distance were significantly lower than those cured at shorter distances (p < 0.05), whereas the FS and DC of the Z3F and SDR specimens were not significantly influenced by increasing distances. The μSBSs of the three types of resin composites reduced with increasing irradiation distances. The FS, μSBS, and DC of the Z3P specimen light-cured at 8 mm for 40 s were comparable to those of the Z3P specimen cured at 0 mm for 20 s. CONCLUSIONS: Increasing the irradiation distance to 8 mm can have a deleterious influence on mechanical performances, including the FS, DC, and dentin μSBS, of the resin composites polymerized with high-irradiance light curing units
Rates for branching particle approximations of continuous discrete filters.
No full textHerein, we analyze an efficient branching particle method for asymptotic solutions to a class of continuous-discrete filtering problems. Suppose that t→Xt is a Markov process and we wish to calculate the measure-valued process t→μt(⋅)≐P{Xt∈⋅|σ{Ytk, tk≤t}}, where tk=kɛ and Ytk is a distorted, corrupted, partial observation of Xtk. Then, one constructs a particle system with observation-dependent branching and n initial particles whose empirical measure at time t, μtn, closely approximates μt. Each particle evolves independently of the other particles according to the law of the signal between observation times tk, and branches with small probability at an observation time. For filtering problems where ɛ is very small, using the algorithm considered in this paper requires far fewer computations than other algorithms that branch or interact all particles regardless of the value of ɛ. We analyze the algorithm on Lévy-stable signals and give rates of convergence for E1/2{‖μnt−μt‖γ2}, where ‖⋅‖γ is a Sobolev norm, as well as related convergence results
Unambiguous Recovery of Multistatic SAR Datafor Nonzero Cross Track Baseline Case
No full textA wide-swath synthetic aperture radar (SAR) image is known to be achievable by merging multistatic aliased data that is collected with an appropriate along-track displacement. However, in terms of both flexibility requirements like potentiality of both along-track and cross-track (XT) interferometry and design requirements like orbital safety, etc., a XT baseline is not only demanded but also unavoidable. In this work, a method is proposed in order to merge SAR data to recover the Doppler spectrum unambiguously for the nonzero XT baseline case. The algorithm is compared and validated by simulating an azimuth invariant multistatic SAR satellite constellation. The results are promising in terms of dealing with XT baselines.Microwave Sensing, Signals & SystemsMathematical Geodesy and Positionin
Finite difference method for detonation waves
No full textAbstractWe study an upwind finite difference scheme for detonation waves. Convergences to weak and strong solutions are discussed with some extra hypothesis. A numerical example shows that beyond these hypothesis, the situation could be more complicated and interesting
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