Use of statistics in civil engineering

Polazeći od tvrdnje da se statističke metode malo primjenjuju, a ponekad, i pogrešno u članku se upozorava na potrebu populariziranja i jače edukacije o primjeni suvremenih statističkih metoda u građevinarstvu. Navode se primjeri neodgovarajuće primjene statističkih proračuna naročito u nekim eksperimentalnim istraživanjima, iz čega proizlaze i neadekvatni zaključci. Ističe se potreba promjene odnosa prema primjeni suvremenih statističkih analiza u građevinskoj znanosti i struci.Starting from the assertion that statistical methods are used quite seldom, and sometimes rather inadequately, in the field of civil engineering, the authors caution that a greater attention should be placed on the popularization and education activities favouring the use of modern statistical calculations in this field. Practical examples are given of inadequate use of statistical calculations, particularly in some experimental research operations, where this may be the cause of inadequate conclusions. The need to change the current perception with respect to the use of modern statistical analysis in the scientific and practical fields of civil engineering is emphasized

The Neuro-genetic approach for estimating the compression index

In the last decade, a number of empirical correlations have been proposed to connect the compression index to other soil parameters, such as liquid limit, plasticity index and the void index. This paper presents a correlation study between the physical properties and compression index which was conducted on normally consolidated clay by the hybridization of two approaches (artificial neuronal networks and genetic algorithms). A comparison was made between the measured experimentally and predictions compression indexes. The obtained results indicate that the Neuro-genetic model has the ability to accurately predict the compression index thus be used in practice by geotechnicians

Reliability Analysis of Bending, Shear and Deflection Criteria of Reinforced Concrete Slabs

Reliability analysis of the safety levels of the criteria for bending, shear and deflection of singly reinforced, concrete slabs, have been evaluated over the practical range of thicknesses 100mm to 250mm.  The First Order Reliability Method was employed in the evaluation procedure for continuous slabs of equal spans as a case study.  Results indicate that the safety margins proposed and associated with the probability of failure (given as 1 x 10-6) for singly reinforced concrete slabs, in the British [CP110; BS8110] and European [EC2] codes for design are not achieved at all.  Also, the reliability levels are not uniform.  Thus, the current design formulations are not as safe and reliable as predicted.  This is because the intrinsic probability of failure, in bending, for example, is only 0.022, which, corresponds to an implied safety level of 2.015. Therefore, the design formulations in these codes need a review so that they can at least meet the target for approved structural safety as prescribed by the Joint Committee on Structural Safety

Intelligent Techniques for Photocatalytic Removal of Pollution in Wastewater

This paper discusses the elimination of C.I. AY23 (Acid Yellow 23) using UV/Ag-TiO2 process. To anticipate the photocatalytic elimination of AY23 with the existence of Ag-TiO2 nanoparticles processed under desired circumstances, two computational techniques namely NN (neural network) and PSO (particle swarm optimization) modeling are developed. A summed up of 100 data are used to establish the models, wherein introductory concentration of dye, UV light intensity, initial dosage of nano Ag-TiO2 and irradiation time are the four parameters applied as the input variables and elimination of AY23 as the output variable. The comparison among the predicted results by designed models and the experimental data proves that the performance of the NN model is comparatively sophisticated than the PSO model

ANWENDUNG DER STATISTIK IM BAUWESEN

Polazeći od tvrdnje da se statističke metode malo primjenjuju, a ponekad, i pogrešno u članku se upozorava na potrebu populariziranja i jače edukacije o primjeni suvremenih statističkih metoda u građevinarstvu. Navode se primjeri neodgovarajuće primjene statističkih proračuna naročito u nekim eksperimentalnim istraživanjima, iz čega proizlaze i neadekvatni zaključci. Ističe se potreba promjene odnosa prema primjeni suvremenih statističkih analiza u građevinskoj znanosti i struci.Starting from the assertion that statistical methods are used quite seldom, and sometimes rather inadequately, in the field of civil engineering, the authors caution that a greater attention should be placed on the popularization and education activities favouring the use of modern statistical calculations in this field. Practical examples are given of inadequate use of statistical calculations, particularly in some experimental research operations, where this may be the cause of inadequate conclusions. The need to change the current perception with respect to the use of modern statistical analysis in the scientific and practical fields of civil engineering is emphasized.En partant de l'assertion que les méthodes statistiques sont utilisées assez rarement, et quelquefois de manière inadéquate, dans le domaine du génie civil, les auteurs soutiennent qu'une attention plus grande devrait être accordée à la popularisation et à l'étude des calculs statistiques modernes dans ce domaine. Les exemples pratiques sont donnés d'un emploi inadéquat des calculs statistiques, notamment dans les recherches expérimentales, où cela peut mener à des conclusions inadéquates. La nécessité de changer la perception courante par rapport à l'usage des analyses statistiques modernes dans les recherches et dans le travail pratique en génie civil est mise en relief.In Bezug zur Behauptung dass man statistische Methoden sehr spärlich anwendet, manchmal auch falsch, wird im Artikel darauf aufmerksam gemacht dass im Bauwesen die Anwendung zeitgemässer statistischer Methoden popularisiert und besser erklärt werden sollte. Angeführt sind Beispiele unentsprechender Anwendung statistischer Berechnungen, besonders in einigen experimentalen Forschungen, woraus auch unadäquate Schlüsse folgen. Hervorgehoben ist die Notwendigkeit der Änderung der Stellungnahme zur Anwendung zeitgemässer statistischer Analysen in der Bauwissenschaft und -Praxis

The Neuro-genetic approach for estimating the compression index

In the last decade, a number of empirical correlations have been proposed to connect the compression index to other soil parameters, such as liquid limit, plasticity index and the void index. This paper presents a correlation study between the physical properties and compression index which was conducted on normally consolidated clay by the hybridization of two approaches (artificial neuronal networks and genetic algorithms). A comparison was made between the measured experimentally and predictions compression indexes. The obtained results indicate that the Neuro-genetic model has the ability to accurately predict the compression index thus be used in practice by geotechnicians

Integrated Fuzzy System and Multi-Expression Programming Techniques for Supplier Selection

Supplier selection problem is a multi-objective problem in which different criteria should be taken into consideration. This article presents a new approach to supplier pre-qualification, supplier selection and evaluation. In the first stage of the model, multi-expression programming (MEP) techniques are used for a supplier pre-qualification. Techniques implemented in MEP allow construction of experiential models using the knowledge contained in the experimental information. Evaluation of the qualified suppliers is done in the second stage using fuzzy logic and Fuzzy Inference System (FIS). In this way, it is possible to retain expert knowledge of the subject phenomenon in a model with the possibility of selecting different operators which lead to the possibility of the faster selection of parameters and making more reliable decisions. Numerical examples are presented to demonstrate the proposed approach