Sources Of Random Uncertainty Research Articles

Probabilistic analysis of FRP efficacy in seismic risk reduction

Engineers are tasked with the challenging task of evaluating the performance and analyzing the risk of systems in the context of performance-based seismic design. All sources of random uncertainty must be taken into account during the design phase in order to complete this assignment. The performance limit states for a structure must be defined using appropriate procedures that take into consideration the system characteristics describing the structure, the soil, and the loads applied to the structural reactions. The main objective of this study is to conduct an in-depth analysis, both linear and non-linear (Pushover), of seismic vulnerability for a reinforced concrete (RC) structure. This aims to probabilistically evaluate the effectiveness of composite materials, particularly those reinforced with glass and carbon fibers, in reducing seismic risk when used to reinforce structural columns. The outcomes of this study will provide valuable insights into the efficacy of FRP reinforcements in enhancing seismic resistance, regardless of the analytical approach adopted (linear or non-linear). They reveal a seismic risk reduction of 48 % for structures equipped with glass fiber-reinforced columns and 67 % for those with carbon fiber-reinforced columns.

Investigation into sources of random uncertainties in the NanoScan-3Di metrological scanning probe microscope

The construction and operation principle of the metrological NanoScan-3Di scanning probe microscope (SPM) are briefly described. This device is a combination of a commercial NanoScan-3D SPM and a three-coordinate heterodyne laser interferometer. The metrological characteristics and main sources of random uncertainties of this measurement complex have been analyzed. The experiments have demonstrated high reproducibility and low noise level when measuring linear displacements on the nanometer-length scale.

The Feasibility of Testing the Inverse Square Law of Gravitation at Newtonian Strength and at Mass Separations of 1 μm

We examine the feasibility of searching for violations of the inverse square law of gravitation with Newtonian strength and at particle separations of 1 μm. We discuss systematic uncertainties, such as spurious forces due to the Casimir force, and various sources of random uncertainty, including those due to patch fields and detector noise. Our analysis suggests that a cryogenic, drag-free space environment is necessary to make the experiment feasible, as thermal and vibrational noise could potentially be reduced to the required level in such an environment.

On estimation of uncertainties in analog measurements (of power systems)

A range of measurements is obtained from a substation that spans peak-load and light-load conditions and includes bus voltages, phase angles and line flows. Then the redundancies in measurements are used to formulate several functions relating these measurements to their attending errors. Minimization of these functions yields the required corrective coefficients. Specifically, the instruments, their arrangement and their characteristics for the 69/13.2 kV South Athens substation of the Athens Utilities Board, are described. Then an error analysis is presented showing the various sources of random uncertainties in the analog measurements. Next the redundancies in the measurements are used to establish several functions whose minimizations provide the required corrective coefficients. This is followed by estimation of propagation of random uncertainties and evaluation of the systematic errors.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A study of uncertainties in the prediction of neutron porosity logging-tool responses

The prediction of logging-tool responses suffers from both systematic and random sources of error of which only the latter can be treated in a scientifically objective manner. The use of a point-energy Monte Carlo code with a versatile modeling package essentially eliminates systematic error. The authors present a detailed discussion of all sources of random uncertainty, with particular reference to the responses of a dual-spaced neutron porosity tool (WILT, Winfrith Logging Tool) in both water and sandstone. Sensitivity analysis is used to identify the principal contributions to the total calculational uncertainty, and the statistical credibility of the comparison between measurements and calculations is discussed. Uncertainty in nuclear cross-sections is shown to be the dominant single source of uncertainty in calculated reaction rates. This applies with particular force as source-counter separation increases. The accuracy of the counting ratio calculation depends largely on the accuracy of the far counter calculation. >