Articles
http://repository.kln.ac.lk/handle/123456789/15894
2024-03-29T11:15:11ZProposed hybrid approach for three-dimensional subsurface simulation to improve boundary determination and design of optimum site investigation plan for pile foundations
http://repository.kln.ac.lk/handle/123456789/26138
Proposed hybrid approach for three-dimensional subsurface simulation to improve boundary determination and design of optimum site investigation plan for pile foundations
Oluwatuyi, O. E.; Rajapakshage, R.; Wulff, S. S.; Ng, K.
Geological uncertainty refers to the changeability of a geomaterial category embedded in another. It arises from predicting a geomaterial category at unobserved locations using categorical data from a site investigation (SI). In the design of bridge foundations, geological uncertainty is often not considered because of the difficulties of assessing it using sparse borehole data, validating the quality of predictions, and incorporating such uncertainties into pile foundation design. To overcome these problems, this study utilizes sparse borehole data and proposes a hybrid approach of various spatial Markov Chain (spMC) models and Monte Carlo simulation to predict three-dimensional (3D) geomaterial categories and assess geological uncertainties. The 3D analysis gives realistic and comprehensive information about the site. Characteristics of the proposed hybrid approach include the estimation of transition rates, prediction of 3D geomaterial categories, and simulation of multiple realizations to propagate the uncertainties quantified by information entropy. This proposed hybrid approach leads to specific novelties that include the development of optimal SI plans to reduce geological uncertainty and the determination of geomaterial layer boundaries according to the quantified geological uncertainty. Reducing the geological uncertainties and accurately determining spatial geomaterial boundaries will improve the design reliability and safety of bridge foundations. The hybrid approach is applied to the Lodgepole Creek Bridge project site in Wyoming to demonstrate the application of the hybrid approach and the associated novelties. Outcomes are cross-validated to evaluate the geomaterial prediction accuracy of the hybrid approach.
2023-01-01T00:00:00ZOptimal Site Investigation Through Combined Geological and Property Uncertainties Analysis
http://repository.kln.ac.lk/handle/123456789/26137
Optimal Site Investigation Through Combined Geological and Property Uncertainties Analysis
Oluwatuyi, O. E.; Ng, K.; Wulff, S. S.; Rajapakshage, R.
Site investigation is crucial in character-
izing the geomaterial profile for the design of bridge
pile foundations. A site investigation plan should be
conducted to maximize geomaterial information and
minimize uncertainty. Thus, both geological and
property uncertainties should be explicitly incorpo-
rated into a site investigation plan. This leads to the
question of how to choose the corresponding optimal
number and location of boreholes in a multiphase
site investigation plan in order to reduce these uncer-
tainties. This study addresses these problems using
multinomial categorical prediction and universal
kriging on a random field with multiple simulations.
Site investigation data for this study are taken from
a bridge project in Iowa, USA, which consists of
four boreholes, each within the proximity of the pile
foundation location. Subsequent numbers of recom-
mended boreholes and their associated locations are
determined to minimize the combined uncertain-
ties. The effectiveness of this combined analysis for
determining an optimal site investigation plan (OSIP)
is validated and compared to an analysis done solely
on property uncertainty. The proposed OSIP yields
a lower prediction error, improves the prediction of
geomaterial type and property, and reduces the sub-
surface uncertainties. The incorporation of OSIP
invariably improves the design efficiency and perfor-
mance of bridge pile foundations
2023-01-01T00:00:00ZAnti-Counterfeit Method for Computer Hardware using Blockchain
http://repository.kln.ac.lk/handle/123456789/25474
Anti-Counterfeit Method for Computer Hardware using Blockchain
Britto, C.D.; Dias, N.G.J.
Counterfeited computer hardware are products designed looks exactly the same as their genuine products. Most of the people are tricked by the counterfeiters using online markets. This influences the need for a secure and efficient mechanism to identify fake/counterfeited products. The proposed method is implemented using the Blockchain technology. Each Block represents a product and the hash key of that product, calculated using the specified Block attributes. The buyer details were updated by a verified retailer. Thereafter any user can check the validity of the product using the hash key and retailer name. Tampered Block is notified to the customer and then the product is invalid. This system can be upgraded by hosting the application on a web server for distribution and separating the application functions according to the user levels (Manufacturer, retailer, and buyer). Therefore, the proposed method provides a more secure and reliable way to handle computer hardware counterfeits.
2022-01-01T00:00:00ZInherent variability assessment from sparse property data of overburden soils and intermediate geomaterials using random field approaches
http://repository.kln.ac.lk/handle/123456789/25470
Inherent variability assessment from sparse property data of overburden soils and intermediate geomaterials using random field approaches
Oluwatuyi, O. E.; Holt, R.; Rajapakshage, R.; Wulff, S. S.; Ng, K.
This study assesses the inherent variability in the geomaterial parameter by quantifying the
parameter uncertainty and develops a site investigation plan with a low degree of uncertainty.
A key research motivation was using sparse borehole data to predict a site geomaterial
configuration in order to determine the design of a site investigation plan. This study develops
a systematic methodology for carrying out a study of inherent variability in light of the
limitations posed by borehole data. The data in this study was provided by the Iowa
Department of Transportation which consisted of eight boreholes from which 92 associated SPT
N-values was considered as the geomaterial parameter of interest. The systematic methodology
then involved the following steps. A general linear model was employed to fit and compare
various spatial covariance models with and without a nugget. These spatial covariance models
were also evaluated with variograms. Predicted SPT N-values were generated using universal
kriging. Simulations were performed conditionally and unconditionally to identify optimal site
investigation plans. The results identified site investigation plans with reduced parameter
uncertainty. The proposed approach can produce site investigation plans that target any or all
geomaterial layers to reduce uncertainty with respect to any geomaterial parameter of interest.
2022-01-01T00:00:00Z