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Article
Publication date: 1 May 1992

LIN JIAHAO and F.W. WILLIAMS

Because of the extensive use of long‐span structures in modern engineering, much attention has been given to the extent to which ground motion phase‐lags affect the…

Abstract

Because of the extensive use of long‐span structures in modern engineering, much attention has been given to the extent to which ground motion phase‐lags affect the internal forces of such structures. In this paper, this problem is studied from the aspect of random seismic analysis, i.e. the random seismic responses of long‐span structures are explored with the phase‐lags of the ground joints of the structures taken into account. The earthquake is regarded as a stationary random process. Formulae for calculating the random responses of the structural displacements and internal forces are derived. Numerical examples are presented which illustrate some basic features of such random response, and also show that the ground motion phase‐lags have considerable effects on structural safety analysis.

Details

Engineering Computations, vol. 9 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 March 2002

JOSE S. PENALVA ZUASTI

This article examines the economic impact of a major California earthquake, by focusing on the catastrophic damage to residential real estate. It asserts that the damage…

Abstract

This article examines the economic impact of a major California earthquake, by focusing on the catastrophic damage to residential real estate. It asserts that the damage, although substantial, would be small relative to the U.S. GNP. The author also asserts that the risk can be optimally allocated through reasonably priced insurance contracts and well‐functioning insurance derivative markets.

Details

The Journal of Risk Finance, vol. 3 no. 4
Type: Research Article
ISSN: 1526-5943

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Article
Publication date: 16 April 2018

Yan Zhao, L.T. Si and H. Ouyang

A novel frequency domain approach, which combines the pseudo excitation method modified by the authors and multi-domain Fourier transform (PEM-FT), is proposed for…

Abstract

Purpose

A novel frequency domain approach, which combines the pseudo excitation method modified by the authors and multi-domain Fourier transform (PEM-FT), is proposed for analyzing nonstationary random vibration in this paper.

Design/methodology/approach

For a structure subjected to a nonstationary random excitation, the closed-form solution of evolutionary power spectral density of the response is derived in frequency domain.

Findings

The deterministic process and random process in an evolutionary spectrum are separated effectively using this method during the analysis of nonstationary random vibration of a linear damped system, only modulation function of the system needs to be estimated, which brings about a large saving in computational time.

Originality/value

The method is general and highly flexible as it can deal with various damping types and nonstationary random excitations with different modulation functions.

Details

Engineering Computations, vol. 35 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 16 April 2018

Xuanhua Fan, Keying Wang and Shifu Xiao

As a practical engineering method, earthquake response spectra play an important role in seismic hazard assessment and in seismic design of structures. However, the…

Abstract

Purpose

As a practical engineering method, earthquake response spectra play an important role in seismic hazard assessment and in seismic design of structures. However, the computing scale and the efficiency of commercial software restricted the solution of complex structures. There is a clear need of developing large-scale and highly efficient finite element procedures for response spectrum analysis.

Design/methodology/approach

In this paper, the kernel theories for earthquake response spectra are deduced and the corresponding parallel solution flow via the modal superposition method is presented. Based on the algorithm and the parallel data structure of JAUMIN framework, a parallel finite element (FE) solution module is established. Using the solution procedure on a supercomputer equipped with up to thousands of processors, the correctness and parallel scalability of the algorithm are evaluated via numerical experiments of typical engineering examples.

Findings

The results show that the solution module has the same precision as the commercial FE software ANSYS; the maximum solution scale achieves 154 million degrees of freedom (DOFs) with a favorable parallel computing efficiency, going far beyond the computing ability of the commercial FE software.

Originality/value

The solution scale in this paper is very challenging for the large-scale parallel computing of structural dynamics and will promote the dynamic analysis ability of complex facilities greatly.

Details

Engineering Computations, vol. 35 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 14 August 2017

Wei Xu, Lingyu Liu and Wei Shang

Timely detection of emergency events and effective tracking of corresponding public opinions are critical in emergency management. As media are immediate sources of…

Abstract

Purpose

Timely detection of emergency events and effective tracking of corresponding public opinions are critical in emergency management. As media are immediate sources of information on emergencies, the purpose of this paper is to propose cross-media analytics to detect and track emergency events and provide decision support for government and emergency management departments.

Design/methodology/approach

In this paper, a novel emergency event detection and opinion mining method is proposed for emergency management using cross-media analytics. In the proposed approach, an event detection module is constructed to discover emergency events based on cross-media analytics, and after the detected event is confirmed as an emergency event, an opinion mining module is used to analyze public sentiments and then generate public sentiment time series for early warning via a semantic expansion technique.

Findings

Empirical results indicate that a specific emergency can be detected and that public opinion can be tracked effectively and efficiently using cross-media analytics. In addition, the proposed system can be used for decision support and real-time response for government and emergency management departments.

Research limitations/implications

This paper takes full advantage of cross-media information and proposes novel emergency event detection and opinion mining methods for emergency management using cross-media analytics. The empirical analysis results illustrate the efficiency of the proposed method.

Practical implications

The proposed method can be applied for detection of emergency events and tracking of public opinions for emergency decision support and governmental real-time response.

Originality/value

This research work contributes to the design of a decision support system for emergency event detection and opinion mining. In the proposed approaches, emergency events are detected by leveraging cross-media analytics, and public sentiments are measured using an auto-expansion of the domain dictionary in the field of emergency management to eliminate the misclassification of the general dictionary and to make the quantization more accurate.

Details

Online Information Review, vol. 41 no. 4
Type: Research Article
ISSN: 1468-4527

Keywords

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Article
Publication date: 25 November 2020

Nibas Apu and Ravi Sinha

Increasing awareness of the society and complying with design requirements of building codes for seismic safety of structures and inhabitants during severe earthquakes are…

Abstract

Purpose

Increasing awareness of the society and complying with design requirements of building codes for seismic safety of structures and inhabitants during severe earthquakes are the primary purpose of seismic analysis. This study aims to present the variability in seismic fragility functions for frames of different heights for the most vulnerable condition of structure using nonlinear time history analysis.

Design/methodology/approach

A total of 4, 8 and 20 stories reinforced concrete (RC) moment-resisting two-dimensional frames are considered for this study. Ground motions (GM) are selected as per the conditional mean spectrum and these are conditioned on a target spectral acceleration at the concern time period. RC frames are designed and detailed as per Indian standards. A concentrated plasticity approach is adopted for non-linear analytical modeling of the RC frames. Deterministic capacity limit states in terms of maximum inter-story drift ratio are considered for different damage states. Fragility functions have been derived following a lognormal distribution from incremental dynamic analysis curves. Finally, the maximum likelihood estimation of the response is obtained for fitting curves with observed fragility.

Findings

The fragility functions of the three structures reflect that under critical or extreme conditions of GM the taller buildings have higher fragility than the shorter buildings for each level of limit states even though both are designed to meet their code-level design forces.

Research limitations/implications

The study is conducted on the extreme scenario of GM conditioned on the fundamental time period of each building, whereas comparison can be developed by selecting various methodologies of GM set. The probabilistic capacity model can be developed for future studies to check the fragility variation with deterministic and probabilistic capacity.

Originality/value

The investigation endeavors to present a comprehensive fragility assessment framework by analytical method. The outcome will be useful in the development of a disaster management strategy for new or old buildings and the response of seismic force with a variation of the building’s height. The findings will also be useful for updating the earthquake-resistant building codes for the new building construction in a similar context.

Details

International Journal of Disaster Resilience in the Built Environment, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-5908

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Article
Publication date: 30 May 2019

J. Esfandiari and Y. Khezeli

An analytical investigation is performed on zipper-braced frames. Zipper-braced frames are an innovative bracing system for steel structures. Conventional…

Abstract

Purpose

An analytical investigation is performed on zipper-braced frames. Zipper-braced frames are an innovative bracing system for steel structures. Conventional inverted-V-braced frames exhibit a design problem arising from the unbalanced vertical force generated by the lower story braces when one of them buckles. This adverse effect can be mitigated by adding zipper columns or vertical members connecting the intersection points of the braces above the first floor.

Design/methodology/approach

This paper critically evaluates over strength, ductility and response modification factors of these structures. To achieve the purpose of this research, several buildings of different stories are considered. Static pushover analysis, linear dynamic analysis and nonlinear incremental dynamic analysis are performed by OpenSees software concerning ten records of past earthquakes.

Findings

Also, ductility factor, over strength factor and response modification factor, has been calculated for zipper-braced frames system. The values of 3.5 and 5 are suggested for response modification factor in ultimate limit state and allowable stress methods, respectively.

Originality/value

The fragility curves were plotted for the first time for such kind of braces. It should be mentioned that these curves play significant roles in evaluating seismic damage of buildings.

Details

World Journal of Engineering, vol. 16 no. 3
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 3 April 2017

François-Xavier Delmonteil and Marie-Ève Rancourt

The devastating impact of catastrophic disasters on terrestrial infrastructure requires the adoption of alternative technology solutions among humanitarian organizations…

Abstract

Purpose

The devastating impact of catastrophic disasters on terrestrial infrastructure requires the adoption of alternative technology solutions among humanitarian organizations. The purpose of this paper is to analyze the role of the most commonly used satellite technologies in relief logistics: imagery and mapping, portable global positioning system (GPS) positioning devices, telecommunications, and GPS vehicle tracking.

Design/methodology/approach

The paper examines both the benefits and limitations of satellite technologies in light of the existing literature and through a complementary questionnaire survey with field workers involved in humanitarian operations in the aftermath of the 2010 Haiti earthquake.

Findings

The results show that the use of satellite technologies can facilitate most of the key logistics challenges encountered by relief actors. However, they also highlight important barriers within humanitarian organizations such as the lack of skilled workers and high costs, underlining the need for long-term training, resource investments, and cooperation between users and technology providers.

Research limitations/implications

The research findings remain valid only in the context of catastrophic disaster responses, which lead to similar destructions, logistical problems, and needs for satellite technologies.

Practical implications

This paper shows how satellite technologies can support humanitarian professionals in the field. It also provides policy recommendations that can facilitate the use of these technologies.

Originality/value

The applications of satellite technologies within humanitarian supply chains are not well-defined in the literature. This paper is the first to be dedicated to analyze the role of the main satellite technologies used in a relief logistics setting.

Details

Journal of Humanitarian Logistics and Supply Chain Management, vol. 7 no. 1
Type: Research Article
ISSN: 2042-6747

Keywords

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Book part
Publication date: 1 January 2004

Jessica Lin and Eamonn Keogh

Given the recent explosion of interest in streaming data and online algorithms, clustering of time series subsequences has received much attention. In this work we make a…

Abstract

Given the recent explosion of interest in streaming data and online algorithms, clustering of time series subsequences has received much attention. In this work we make a surprising claim. Clustering of time series subsequences is completely meaningless. More concretely, clusters extracted from these time series are forced to obey a certain constraint that is pathologically unlikely to be satisfied by any dataset, and because of this, the clusters extracted by any clustering algorithm are essentially random. While this constraint can be intuitively demonstrated with a simple illustration and is simple to prove, it has never appeared in the literature. We can justify calling our claim surprising, since it invalidates the contribution of dozens of previously published papers. We will justify our claim with a theorem, illustrative examples, and a comprehensive set of experiments on reimplementations of previous work.

Details

Applications of Artificial Intelligence in Finance and Economics
Type: Book
ISBN: 978-1-84950-303-7

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Article
Publication date: 8 January 2020

Hailiang Su, Fengchong Lan, Yuyan He and Jiqing Chen

Because of the high computational efficiency, response surface method (RSM) has been widely used in structural reliability analysis. However, for a highly nonlinear limit…

Abstract

Purpose

Because of the high computational efficiency, response surface method (RSM) has been widely used in structural reliability analysis. However, for a highly nonlinear limit state function (LSF), the approximate accuracy of the failure probability mainly depends on the design point, and the result is that the response surface function composed of initial experimental points rarely fits the LSF exactly. The inaccurate design points usually cause some errors in the traditional RSM. The purpose of this paper is to present a hybrid method combining adaptive moving experimental points strategy and RSM, describing a new response surface using downhill simplex algorithm (DSA-RSM).

Design/methodology/approach

In DSA-RSM, the operation mechanism principle of the basic DSA, in which local descending vectors are automatically generated, was studied. Then, the search strategy of the basic DSA was changed and the RSM approximate model was reconstructed by combining the direct search advantage of DSA with the reliability mechanism of response surface analysis.

Findings

The computational power of the proposed method is demonstrated by solving four structural reliability problems, including the actual engineering problem of a car collision. Compared to specific structural reliability analysis methods, the approach of modified DSA interpolation response surface for structural reliability has a good convergent capability and computational accuracy.

Originality/value

This paper proposes a new RSM technology based on proxy model to complete the reliability analysis. The originality of this paper is to present an improved RSM that adjusts the position of the experimental points judiciously by using the DSA principle to make the fitted response surface closer to the actual limit state surface.

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