The Experts below are selected from a list of 34644 Experts worldwide ranked by ideXlab platform
Walter Binder - One of the best experts on this subject based on the ideXlab platform.
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jp2 call site aware calling context profiling for the java virtual machine
Science of Computer Programming, 2014Co-Authors: Aibek Sarimbekov, Walter Binder, Philippe Moret, Andreas Sewe, Mira MeziniAbstract:Calling context profiling fulfills programmers' information needs to obtain a complete picture of a program's inter- and intra-procedural control flow, which are important for workload characterization, debugging, profiling, program comprehension, and reverse engineering. Many existing calling context Profilers for Java, however, resort to sampling or other incomplete instrumentation techniques; thus, they collect incomplete profiles only. In this article we present JP2, a new calling context Profiler for the Java Virtual Machine, which collects profiles that are not only complete but also call-site aware; that is, JP2 is able to distinguish between multiple call sites within a single method. JP2 supports selective profiling of the dynamic extent of chosen methods and supports profiling of native method invocations. Moreover, produced profiles contain execution statistics at the level of individual basic blocks of code, thereby preserving the intra-procedural control flow of the profiled applications. We rigorously evaluate the overhead incurred by JP2. This overhead is acceptable in tasks such as workload characterization. JP2 is freely available under an Open Source license.
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complete and platform independent calling context profiling for the java virtual machine
Electronic Notes in Theoretical Computer Science, 2011Co-Authors: Aibek Sarimbekov, Walter Binder, Philippe Moret, Andreas Sewe, Mira MeziniAbstract:Calling context profiling collects statistics separately for each calling context. Complete calling context profiles that faithfully represent overall program execution are important for a sound analysis of program behavior, which in turn is important for program understanding, reverse engineering, and workload characterization. Many existing calling context Profilers for Java rely on sampling or on incomplete instrumentation techniques, yielding incomplete profiles; others rely on Java Virtual Machine (JVM) modifications or work only with one specific JVM, thus compromising portability. In this paper we present a new calling context Profiler for Java that reconciles completeness of the collected profiles and full compatibility with any standard JVM. In order to reduce measurement perturbation, our Profiler collects platform-independent dynamic metrics, such as the number of method invocations and the number of executed bytecodes. In contrast to prevailing calling context Profilers, our tool is able to distinguish between multiple call sites in a method and supports selective profiling of (the dynamic extent of) certain methods. We have evaluate the overhead introduced by our Profiler with standard Java and Scala benchmarks on a range of different JVMs.
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locating performance bottlenecks in embedded java software with calling context cross profiling
Quantitative Evaluation of Systems, 2009Co-Authors: Philippe Moret, Walter Binder, Danilo Ansaloni, Alex Villazon, Martin SchoeberlAbstract:Prevailing approaches to analyze embedded software performance either require the deployment of the software on the embedded target, which can be tedious and may be impossible in an early development phase, or rely on simulation, which can be extremely slow. We promote cross-profiling as an alternative approach, which is particularly well suited for embedded Java processors. The embedded software is profiled in any standard Java Virtual Machine in a host environment, but the generated cross-profile estimates the execution time on the target. We implemented our approach in the customizable cross-Profiler CProf, which generates calling-context cross-profiles. Each calling-context stores dynamic metrics, such as the estimated CPU cycle consumption on the target. We visualize the generated calling-context cross-profiles as ring charts, where callee methods are represented in segments surrounding the caller's segment. As the size of each segment corresponds to the relative CPU consumption of the corresponding calling-context, the visualization eases the location of performance bottlenecks in embedded Java software, revealing hot methods, as well as their callers and callees, at one glance.
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analyzing performance and dynamic behavior of embedded java software with calling context cross profiling
Principles and Practice of Programming in Java, 2009Co-Authors: Philippe Moret, Walter Binder, Alex Villazon, Martin Schoeberl, Danilo AnsaloniAbstract:Prevailing approaches to analyze embedded software performance either require the deployment of the software on the embedded target, which can be tedious and may be impossible in an early development phase, or rely on simulation, which can be extremely slow. We promote cross-profiling as an alternative approach, which is particularly well suited for embedded Java processors. The embedded software is profiled in any standard Java Virtual Machine in a host environment, but the generated cross-profile estimates the execution time on the target. We implemented our approach in the customizable cross-Profiler CProf, which generates calling-context cross-profiles. Each calling-context stores dynamic metrics, such as the estimated CPU cycle consumption on the target. We visualize the generated calling-context cross-profiles as ring charts, where callee methods are represented in segments surrounding the caller's segment. As the size of each segment corresponds to the relative CPU consumption of the corresponding calling-context, the visualization eases the location of performance bottlenecks in embedded Java software, revealing hot methods, as well as their callers and callees, at one glance.
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a portable and customizable profiling framework for java based on bytecode instruction counting
Asian Symposium on Programming Languages and Systems, 2005Co-Authors: Walter BinderAbstract:Prevailing Profilers for Java, which rely on standard, native-code profiling interfaces, are not portable, give imprecise results due to serious measurement perturbation, and cause excessive overheads. In contrast, program transformations allow to generate reproducible profiles in a fully portable way with significantly less overhead. This paper presents a profiling framework that instruments Java programs at the bytecode level to build context-sensitive execution profiles at runtime. The profiling framework includes an exact Profiler as well as a sampling Profiler. User-defined profiling agents can be written in pure Java, too, in order to customize the runtime processing of profiling data.
Toshitaka Tsuda - One of the best experts on this subject based on the ideXlab platform.
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preliminary observation of temperature profiles by radio acoustic sounding system rass with a 1280 mhz lower atmospheric wind Profiler at gadanki india
Atmospheric Measurement Techniques Discussions, 2012Co-Authors: T Chandrasekhar V Sarma, P Srinivasulu, Toshitaka TsudaAbstract:A UHF wind Profiler operating at 1280 MHz has been developed at NARL for atmospheric studies in the planetary boundary layer. In order to explore application of radio acoustic sounding system (RASS) technique to this Profiler, a suitable acoustic attachment was designed and preliminary experiments were conducted on 27–30 August 2010. Height profiles of virtual temperature, T v , in the planetary boundary layer were derived with 1 μs and 0.25 μs pulse transmission, corresponding to a height resolution of 150 m and about 40 m, respectively. Diurnal variation of T v is clearly recognized, and perturbations of T v are also seen in association with a precipitation event. Simultaneous profiles obtained from the MST Radar-RASS and an onsite 50 m tower demonstrate the capability to continuously profile the atmospheric temperature from near the ground to upper tropospheric altitudes.
Chris Lennard - One of the best experts on this subject based on the ideXlab platform.
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short tandem repeat str genotyping of keratinised hair part 2 an optimised genomic dna extraction procedure reveals donor dependence of str profiles
Forensic Science International, 2005Co-Authors: Dennis Mcnevin, Linzi Wilsonwilde, James Robertson, Jennelle M Kyd, Chris LennardAbstract:Abstract A feasibility study of short tandem repeat (STR) genotyping of telogen phase hairs in particular, and hair shaft in general, is presented. A number of extraction procedures in common use were investigated and the quantities of nuclear DNA (nuDNA) delivered were quantified via a real-time PCR assay. The extracts were subjected to two variations on AmpFlSTR ® Profiler Plus™ PCR amplification strategies (extended cycles, two rounds of PCR) and the genotypes compared. Nuclear DNA was found to persist in human hair shafts, albeit at very low levels. Full Profiler Plus™ profiles consistent with the hair donor were obtained from 100mg hair shaft samples (bleached and unbleached). These were, however, mixed profiles, indicating low copy number (LCN) contamination in the extracts. Single telogen hair clubs and single hair shafts delivered partial profiles with usually only one allele of heterozygous loci. Telogen phase hairs yielded the same amount of nuDNA (and no more) as hair shafts (either anagen or telogen). Whether hair shafts dissolved or not in lysis buffer had no effect on either the quantitated yield of DNA or on the chance of obtaining a correct genotype. These results provide evidence that genomic DNA resides on the exterior of the hair shaft and we use this information to suggest an optimal procedure for nuDNA extraction from keratinised hair samples: soaking hairs in simple digestion buffers containing Tris–HCl, a salt and a chelating agent without prior cleaning of the hair shafts. It is proposed that cleaning removes most of the recoverable DNA. This procedure was applied to obtain genotypes from 3cm hair shafts which matched reference profiles from the donors at up to 9 out of 10 AmpFlSTR ® Profiler Plus™ STR loci. When the genotyping success was measured by counting the number of matches between the two dominant alleles at each locus for each extract with the reference DNA profile of the hair donor, the success was found to be highly dependent on the donor. The number of matching alleles varied between not less than 10 for one donor to no more than two for another donor. These results may well be linked to the environmental experience of the hairs from each donor prior to removal.
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rapid communication short tandem repeat str genotyping of keratinised hair part 2 an optimised genomic dna extraction procedure reveals donor dependence of str profiles
2005Co-Authors: Dennis Mcnevin, Linzi Wilsonwilde, James Robertson, Jennelle M Kyd, Chris LennardAbstract:A feasibility study of short tandem repeat (STR) genotyping of telogen phase hairs in particular, and hair shaft in general, is presented. A number of extraction procedures in common use were investigated and the quantities of nuclear DNA (nuDNA) delivered were quantified via a real-time PCR assay. The extracts were subjected to two variations on AmpF‘STR 1 Profiler Plus TM PCR amplification strategies (extended cycles, two rounds of PCR) and the genotypes compared. Nuclear DNA was found to persist in human hair shafts, albeit at very low levels. Full Profiler Plus TM profiles consistent with the hair donor were obtained from 100 mg hair shaft samples (bleached and unbleached). These were, however, mixed profiles, indicating low copy number (LCN) contamination in the extracts. Single telogen hair clubs and single hair shafts delivered partial profiles with usually only one allele of heterozygous loci. Telogen phase hairs yielded the same amount of nuDNA (and no more) as hair shafts (either anagen or telogen). Whether hair shafts dissolved or not in lysis buffer had no effect on either the quantitated yield of DNA or on the chance of obtaining a correct genotype. These results provide evidence that genomic DNA resides on the exteriorof thehair shaft and we use this information tosuggest an optimal procedure fornuDNA extraction from keratinised hair samples: soaking hairs in simple digestion buffers containing Tris‐HCl, a salt and a chelating agent without prior cleaning of the hair shafts. It is proposed that cleaning removes most of the recoverable DNA. This procedure was applied to obtain genotypes from 3 cm hair shafts which matched reference profiles from the donors at up to 9 out of 10 AmpF‘STR 1 Profiler Plus TM STR loci. When the genotyping success was measured by counting the number of matches between the two dominant alleles at each locus for each extract with the reference DNA profile of the hair donor, the success was found to be highly dependent on the donor. The number of matching alleles varied between not less than 10 for one donor to no more than two for another donor. These results may well be linked to the environmental experience of the hairs from each donor prior to removal. # 2005 Elsevier Ireland Ltd. All rights reserved.
T Chandrasekhar V Sarma - One of the best experts on this subject based on the ideXlab platform.
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preliminary observation of temperature profiles by radio acoustic sounding system rass with a 1280 mhz lower atmospheric wind Profiler at gadanki india
Atmospheric Measurement Techniques Discussions, 2012Co-Authors: T Chandrasekhar V Sarma, P Srinivasulu, Toshitaka TsudaAbstract:A UHF wind Profiler operating at 1280 MHz has been developed at NARL for atmospheric studies in the planetary boundary layer. In order to explore application of radio acoustic sounding system (RASS) technique to this Profiler, a suitable acoustic attachment was designed and preliminary experiments were conducted on 27–30 August 2010. Height profiles of virtual temperature, T v , in the planetary boundary layer were derived with 1 μs and 0.25 μs pulse transmission, corresponding to a height resolution of 150 m and about 40 m, respectively. Diurnal variation of T v is clearly recognized, and perturbations of T v are also seen in association with a precipitation event. Simultaneous profiles obtained from the MST Radar-RASS and an onsite 50 m tower demonstrate the capability to continuously profile the atmospheric temperature from near the ground to upper tropospheric altitudes.
M A Shapiro - One of the best experts on this subject based on the ideXlab platform.
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radio acoustic sounding system rass and wind Profiler observations of lower and midtropospheric weather systems
Monthly Weather Review, 1992Co-Authors: Paul J Neiman, Peter T May, M A ShapiroAbstract:Abstract The National 0ceanic and Atmospheric Administration (NOAA) Wave Propagation Laboratory (WPL) wind Profilers and accompanying radio acoustic sounding system (RASS) temperature Profilers in eastern Colorado jointly measure nearly continuous (≤1 h), high vertical resolution (≤300 m) wind-velocity and virtual-temperature profiles. This study presents NOAA/WPL wind Profiler and RASS observations and diagnostics of propagating lower- and midtropospheric weather systems over Colorado. The wind and temperature remote-sensing systems observed wind-velocity and virtual-temperature structures associated with a synoptic-scale trough and embedded fronts, and a propagating short-wave trough and trailing midtropospheric jet-stream-frontal-zone (jet-front) system. Single-station hourly diagnostic calculations of geopotential heights, horizontal virtual potential temperature gradients, thermal advections, vertical velocities gradient Richardson numbers, and cross-frontal isentropic potential vorticity demonstrate...
