586,967 research outputs found
A Practical Blended Analysis for Dynamic Features in JavaScript
The JavaScript Blended Analysis Framework is designed to
perform a general-purpose, practical combined static/dynamic
analysis of JavaScript programs, while handling dynamic
features such as run-time generated code and variadic func-
tions. The idea of blended analysis is to focus static anal-
ysis on a dynamic calling structure collected at runtime in
a lightweight manner, and to rene the static analysis us-
ing additional dynamic information. We perform blended
points-to analysis of JavaScript with our framework and
compare results with those computed by a pure static points-
to analysis. Using JavaScript codes from actual webpages
as benchmarks, we show that optimized blended analysis
for JavaScript obtains good coverage (86.6% on average per
website) of the pure static analysis solution and nds ad-
ditional points-to pairs (7.0% on average per website) con-
tributed by dynamically generated/loaded code
Nanoscale resolution interrogation scheme for simultaneous static and dynamic fiber Bragg grating strain sensing
A combined interrogation and signal processing technique which facilitates high-speed simultaneous static and dynamic strain demodulation of multiplexed fiber Bragg grating sensors is described. The scheme integrates passive, interferometric wavelength-demodulation and fast optical switching between wavelength division multiplexer channels with signal extraction via a software lock-in amplifier and fast Fourier transform. Static and dynamic strain measurements with noise floors of 1 nanostrain and 10 nanostrain/sqrt(Hz), between 5 mHz and 2 kHz were obtained. An inverse analysis applied to a cantilever beam set up was used to characterise and verify strain measurements using finite element modeling. By providing distributed measurements of both ultahigh-resolution static and dynamic strain, the proposed scheme will facilitate advanced structural health monitoring
Double symbolic joint entropy in nonlinear dynamic complexity analysis
Symbolizations, the base of symbolic dynamic analysis, are classified as
global static and local dynamic approaches which are combined by joint entropy
in our works for nonlinear dynamic complexity analysis. Two global static
methods, symbolic transformations of Wessel N. symbolic entropy and base-scale
entropy, and two local ones, namely symbolizations of permutation and
differential entropy, constitute four double symbolic joint entropies that have
accurate complexity detections in chaotic models, logistic and Henon map
series. In nonlinear dynamical analysis of different kinds of heart rate
variability, heartbeats of healthy young have higher complexity than those of
the healthy elderly, and congestive heart failure (CHF) patients are lowest in
heartbeats' joint entropy values. Each individual symbolic entropy is improved
by double symbolic joint entropy among which the combination of base-scale and
differential symbolizations have best complexity analysis. Test results prove
that double symbolic joint entropy is feasible in nonlinear dynamic complexity
analysis.Comment: 7 pages, 4 figure
The Vibroacoustic Analysis of The Hydrocarbon Processing Plant Piping System Operating at Elevated Temperature.
In this paper it is presented the vibroacoustic analysis of the selected section of the
hydrocarbon processing chemical plant piping system operating at elevated temperature and subjected to dynamic load exciting vibration of the structure. The pump suction and discharge piping system is a part of chemical plant for processing hydrocarbon mixture at 270° C. Elevated temperature is one of static loads that influences the boundary conditions of the piping structure thus generating pump nozzle loadings leading to possible pump body deflection. Deflected shape of the pump body results in generation of flow fluctuation, visible and measurable as a pressure pulsation. This kind of fluctutation has been assumed further to be one of the dynamic loading on piping system structure. The dynamic analysis was performed to quantify the loading effect of pressure pulsation excited in the pump discharge nozzles on the structure of pipelines and the connected pump nozzles. The simulation was based on the numerical analysis of the excitation by acoustic waves propagation in subjected piping system. Measured on–site pressure pulsation at pumps nozzles has been identified and assumed to be the source of the acoustic waves. In the simulation elastic features of the piping structure as well as the fluid, and pressure loses in pipes, taken into account. Final result of the acoustic part of
the simulation was spectral characteristics of the acoustic shock forces, defined further as harmonic loads for the dynamic structural analysis. To observe an influence of the acoustic excitation on the piping there was performed structural analysis of the piping system and the combined results of static and dynamic loading influence determined. This part of the analysis has been perfomed by means of FEM computer software Bentley AutoPIPE as well as some use of ANSYS FEM program. Important step in this simulation there was the theoretical modal analysis. This analysis allows to predict possible vibroacoustic resonance in the structural system under specific conditions of the coincidence between acoustic excitation and modals. The results of the combined static and dynamic loadings analysis contain the information on the node displacements, internal forces, resulting stresses in the pipe walls and loads on the pump nozzles and piping supports
Turbulence-resolving simulations of wind turbine wakes
Turbulence-resolving simulations of wind turbine wakes are presented using a
high--order flow solver combined with both a standard and a novel dynamic
implicit spectral vanishing viscosity (iSVV and dynamic iSVV) model to account
for subgrid-scale (SGS) stresses. The numerical solutions are compared against
wind tunnel measurements, which include mean velocity and turbulent intensity
profiles, as well as integral rotor quantities such as power and thrust
coefficients. For the standard (also termed static) case the magnitude of the
spectral vanishing viscosity is selected via a heuristic analysis of the wake
statistics, while in the case of the dynamic model the magnitude is adjusted
both in space and time at each time step. The study focuses on examining the
ability of the two approaches, standard (static) and dynamic, to accurately
capture the wake features, both qualitatively and quantitatively. The results
suggest that the static method can become over-dissipative when the magnitude
of the spectral viscosity is increased, while the dynamic approach which
adjusts the magnitude of dissipation locally is shown to be more appropriate
for a non-homogeneous flow such that of a wind turbine wake
Fast approximately timed simulation
International audienceIn this paper we present a technique for fast approximately timed simulation of software within a virtual prototyping framework. Our method performs a static analysis of the program control flow graph to construct annotations of the simulated program, combined with dynamic performance information. The static analysis estimates execution time based on a target architecture model. The delays introduced by instruction fetch and data cache misses are evaluated dynamically. At the end of each block, static and dynamic information are combined with branch target prediction to compute the total execution time of the blocks. As a result, we can provide approximate performance estimates with a high simulation speed that is still usable for software developers
Detection of static and dynamic activities using uniaxial accelerometers
Rehabilitation treatment may be improved by objective analysis of activities of daily living. For this reason, the feasibility of distinguishing several static and dynamic activities (standing, sitting, lying, walking, ascending stairs, descending stairs, cycling) using a small set of two or three uniaxial accelerometers mounted on the body was investigated. The accelerometer signals can be measured with a portable data acquisition system, which potentially makes it possible to perform online detection of static and dynamic activities in the home environment. However, the procedures described in this paper have yet to be evaluated in the home environment. Experiments were conducted on ten healthy subjects, with accelerometers mounted on several positions and orientations on the body, performing static and dynamic activities according to a fixed protocol. Specifically, accelerometers on the sternum and thigh were evaluated. These accelerometers were oriented in the sagittal plane, perpendicular to the long axis of the segment (tangential), or along this axis (radial). First, discrimination between the static or dynamic character of activities was investigated. This appeared to be feasible using an rms-detector applied on the signal of one sensor tangentially mounted on the thigh. Second, the distinction between static activities was investigated. Standing, sitting, lying supine, on a side and prone could be distinguished by observing the static signals of two accelerometers, one mounted tangentially on the thigh, and the second mounted radially on the sternum. Third, the distinction between the cyclical dynamic activities walking, stair ascent, stair descent and cycling was investigated. The discriminating potentials of several features of the accelerometer signals were assessed: the mean value, the standard deviation, the cycle time and the morphology. Signal morphology was expressed by the maximal cross-correlation coefficients with template signals for the different dynamic activities. The mean signal values and signal morphology of accelerometers mounted tangentially on the thigh and the sternum appeared to contribute to the discrimination of dynamic activities with varying detection performances. The standard deviation of the signal and the cycle time were primarily related to the speed of the dynamic activities, and did not contribute to the discrimination of the activities. Therefore, discrimination of dynamic activities on the basis of the combined evaluation of the mean signal value and signal morphology is propose
Ednem: A Malware Detection Framework Based on Static and Dynamic Analysis
Information technology is now at the core of many basic needs, and spreading to all industries, not limited to financial transactions, critical infrastructures, military logistics, traveling, shopping, and education. Software and hardware both have flaws, and, especially when unwitting users use computers, these flaws can be exploited by malicious authors to wreak havoc. Software code is the core of information technology, and weaknesses in software applications are exploited using sophisticated malware purposely designed to circumvent security measures. Malware authors these days employ varied tactics, such as encryption, compression, and polymorphic and metamorphic approaches to hide their intentions. The majority of malware are obfuscated. Detecting malware using static analysis is not enough; combining static and dynamic analysis especially at kernel level is critical to curb malware activities, especially at runtime when intended behaviors can be captured and learned at the kernel mode based on their activities. Ednem Analysis Tool uses both static and dynamic analysis to observe malware at the kernel level to understand the intricacies of malware in order to classify them as benign or malicious. Our evaluation and testing results show that Ednem Analysis Tool detected 87% of the malware samples during static analysis, and, when combined with dynamic analysis, the detection rate increased to 97 .42%. Static detection from similar tools such as PortEx Analyzer and Pev were 73.57% and 38.41%, respectively. Ednem is effective when static and dynamic analysis are combined to detect malware. Researchers can use Ednem Analysis Tool to perform reverse engineering and to learn the behavior of malware
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