Multi-classifier information fusion in risk analysis

The present review examines decision-making methods developed for dealing with uncertainties and applied to solve problems of civil engineering. Several methodological difficulties emerging from uncertainty quantification in decision-making are identified. The review is focused on formal methods of multiple criteria decision-making (MCDM). Handling of uncertainty by means of fuzzy logic and probabilistic modelling is analysed in light of MCDM. A sensitivity analysis of MCDM problems with uncertainties is discussed. An application of stochastic MCDM methods to a design of safety critical objects of civil engineering is considered. Prospects of using MCDM under uncertainty in developing areas of civil engineering are discussed in brief. These areas are design of sustainable and energy efficient buildings, building information modelling, and assurance of security and safety of built property. It is stated that before long the decision-making in civil engineering may face several methodological problems: the need to combine fuzzy and probabilistic representations of uncertainties in one decision-making matrix, the necessity to extend a global sensitivity analysis to all input elements of a MCDM problem with uncertainties, and an application of MCDM methods in the areas of civil engineering where decision-making under uncertainty is presently not common.

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Solving Civil Engineering Problems by Means of Fuzzy and Stochastic MCDM Methods: Current State and Future Research

Background: The brain's continuous neural activity during sleep can be monitored by electroencephalogram (EEG) signals. The EEG wave pattern and frequency vary during five stages of sleep. These subtle variations in sleep EEG signals cannot be easily detected through visual inspection. Summary: A range of time, frequency, time-frequency and nonlinear analysis methods can be applied to understand the complex physiological signals and their chaotic behavior. This paper presents a comprehensive comparative review and analysis of 29 nonlinear dynamics measures for EEG-based sleep stage detection. Key Messages: The characteristic ranges of these features are reported for the five different sleep stages. All nonlinear measures produce clinically significant results, that is, they can discriminate the individual sleep stages. Feature ranking based on the statistical F-value, however, shows that the third order cumulant of higher order spectra yields the most discriminative result. The distinct value ranges for each sleep stage and the discriminative power of the features can be used for sleep disorder diagnosis, treatment monitoring, and drug efficacy assessment.

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Nonlinear Dynamics Measures for Automated EEG-Based Sleep Stage Detection.

Metaheuristic optimization within machine learning-based classification system for early warnings related to geotechnical problems

Condition assessment of shield tunnel using a new indicator: The tunnel serviceability index

Fuzzy analytic hierarchy process (fuzzy-AHP) synthetic evaluation models were applied to address the uncertainties in tunnel health evaluation These uncertainties occur because of a lack of specific information, missing data, misleading or conflicting information due to the complex nature of geo-materials, and even the ambiguity in the concept of tunnel health This fuzzy-AHP synthetic evaluation model merges different types of data from multiple sensors to map them into the health rating scores of shield tunnels A piecewise distribution was chosen for membership functions, and an exponential scale was introduced for a better characterization of the scales for weight sets A series of fuzzy operators were defined to yield the fuzzy synthetic evaluation indexes (FSEIs) for monitoring factors and the fuzzy-AHP evaluation procedure applied to the models was demonstrated In order to verify the feasibility and efficiency of the models and the procedure, a case study on Nanjing Yangtze River Tunnel was presented The calculated FSEIs were compared with the rating scales to determine the corresponding action strategies The fuzzy-AHP health evaluations for monitoring factors, segments, rings, and the whole tunnel were implemented in succession using the models and following the procedure The segments with poor health conditions can then be identified for administrative maintenance or repair The investigations presented indicate that the proposed fuzzy-AHP models characterize the fuzziness of tunnel health and will be useful for clarifying the tunnel health evaluation uncertainties to both designers and administrators These evaluations will result in enhancing the knowledge of designers and aid them for the optimization of the design of similar tunnels

Fuzzy Analytic Hierarchy Process Synthetic Evaluation Models for the Health Monitoring of Shield Tunnels

Intelligent sensor network-based emergency tunnel defect monitoring system

The invention provides a fire-resistant optimized design method for a reinforced concrete bidirectional compartment floor between a metro depot and a superstructure. The fire-resistant optimized design method comprises the following steps of establishing a numerical model of the floor according to four-sided clamped conditions through adopting a finite element method firstly, dividing finite element grids, calculating and drawing a deflection-time curve after burning and finding out inflection points of curvature on the curve; determining the distribution of plastic hinge lines at the inflection points and the node rotation amount of a hinge outlet section by adopting a subdivision node search method; calculating the thin film force and the section resistance at the plastic hinge lines through the plastic hinge rotation amount according to the material performance of concrete and rebars at corresponding temperature, and determining the corresponding residual bearing force of a burned plate; calculating the fire-resistant time and the residual bearing force of the burned reinforced concrete bidirectional plate, and carrying out optimized design. According to the fire-resistant optimized design method provided by the invention, the actual fire-resistant time and the residual bearing force after burning of the reinforced concrete bidirectional compartment floor can be accurately predicted, the construction cost increased for 3-hour fire-resistant duration time can be reduced, and the purpose of reducing the cost is achieved.

Zhang Yuncong

Papers

Fuzzy Analytic Hierarchy Process Synthetic Evaluation Models for the Health Monitoring of Shield Tunnels

Intelligent sensor network-based emergency tunnel defect monitoring system

Fire-resistant optimized design method for reinforced concrete bidirectional compartment floor of metro depot