SOAP Services with Clarens: Guide for Developers and Administrators

The Clarens application server enables secure, asynchronous SOAP services to run on a Grid cluster such as one of those of the TeraGrid. There is a Client, who wants to use the service and understands the application domain enough to form a reasonable service request; a Developer, who is a power-user of the TeraGrid, who understands both Clarens and the application domain, and creates and deploys a service on a TeraGrid head node; and there is a Root system administrator, who controls the Clarens installation and the cluster on which it runs. The purpose of this document is to provide all of the information a service developer needs to know in order to deploy a Clarens service, with information also provided for the system administrator of the Clarens installation. First we discuss how each of the three roles see the service

MEASURING THE PERFORMANCE COST OF MANUAL SYSTEM CALL DETECTIONS VIA PROCESS INSTRUMENTATION CALLBACK (PIC)

This quasi-experimental before-and-after study measured the performance impact of using Process Instrumentation Callback (PIC) to detect the use of manual system calls on the Windows operating system. The Windows Application Programming Interface (WinAPI), the impacts of system call monitoring, and the limitations of current detection mechanisms and their downsides were reviewed in-depth. Previous literature was evaluated that identified PIC as a unique solution to monitor system calls entirely from User-Mode, being able to rely on the Windows Kernel to intercept a target process. Unlike previous monitoring techniques, PIC must handle all system calls when performing analysis which requires an increase in processing. The impact on a single process was evaluated by recording CPU time, memory utilization, and clock time. Three different iterations that performed additional analysis were developed and tested to determine the cost of increased fidelity in detection. Results showed a statistically significant increase when PIC was applied in each version. However, the rate of impact was drastically reduced by restricting dynamic lookups to process initialization and the elimination of the Microsoft Debugging Engine. Future integration with existing detection mechanisms such as User-Mode hooks and Event-Tracing for Windows is encouraged and discussed

Análisis contrastivo de la negación gramatical en español y en agni morofué

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Ligand-receptor binding kinetics in surface plasmon resonance cells: A Monte Carlo analysis

Surface plasmon resonance (SPR) chips are widely used to measure association and dissociation rates for the binding kinetics between two species of chemicals, e.g., cell receptors and ligands. It is commonly assumed that ligands are spatially well mixed in the SPR region, and hence a mean-field rate equation description is appropriate. This approximation however ignores the spatial fluctuations as well as temporal correlations induced by multiple local rebinding events, which become prominent for slow diffusion rates and high binding affinities. We report detailed Monte Carlo simulations of ligand binding kinetics in an SPR cell subject to laminar flow. We extract the binding and dissociation rates by means of the techniques frequently employed in experimental analysis that are motivated by the mean-field approximation. We find major discrepancies in a wide parameter regime between the thus extracted rates and the known input simulation values. These results underscore the crucial quantitative importance of spatio-temporal correlations in binary reaction kinetics in SPR cell geometries, and demonstrate the failure of a mean-field analysis of SPR cells in the regime of high Damk\"ohler number Da > 0.1, where the spatio-temporal correlations due to diffusive transport and ligand-receptor rebinding events dominate the dynamics of SPR systems.Comment: 21 pages, 9 figure

An Architecture for Scaling NVO Services to TeraGrid

The term "cyberinfrastructure" has been adopted by the US National Science Foundation to mean "advanced computing engines, data archives and digital libraries, observation and sensor systems, and other research and education instrumentation [linked] into a common framework". One of the largest awards in this program is the TeraGrid, a linkage of large supercomputer centers based on the Globus software. Another cyberinfrastructure program is the National Virtual Observatory, a linkage of astronomical data publishers into a service-oriented framework. There are different philosophies behind the TeraGrid and the NVO architecture. This note explains a proposed service-oriented architecture for TeraGrid nodes that is an attempt to bridge these ways of working, and a prototype instantiation at Caltech

Formative assessment: Comparing immediate and delayed feedback

The current study compared feedback via the Immediate Feedback Assessment Technique to typical scantron with delayed feedback. Following students during the course of one semester in two introductory psychology courses, students alternated between using the IFAT and using a typical scantron with feedback for formative assessment before taking each exam. Summative examination (post-tests) performance on assessments containing questions comparable and identical to questions seen on formative pre-tests were compared in order to assess any differences in performance depending on type of formative assessment and feedback experienced. Results showed mixed findings as to whether the IFAT is more effective at increasing retention compared to more delayed feedback using the typical scantron response form. Limitations and future directions are provided