Weihua Zhang, Yuanchen Zeng, Dongli Song and Zhiwei Wang
The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system. This paper aims to…
Abstract
Purpose
The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system. This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice. The key principles and approaches will be proposed, and their applications to high-speed trains in China will be presented.
Design/methodology/approach
First, the structural integrity and dynamical integrity of high-speed trains are defined, and their relationship is introduced. Then, the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided. Finally, the principles and approaches for assessing the dynamical integrity of high-speed trains are presented and a novel operational assessment method is further presented.
Findings
Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system. For assessing the structural integrity of structural components, an open-loop analysis considering both normal and abnormal vehicle conditions is needed. For assessing the structural integrity of dynamical components, a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed. The analysis of vehicle system dynamics should follow the principles of complete objects, conditions and indices. Numerical, experimental and operational approaches should be combined to achieve effective assessments.
Originality/value
The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects, better lifespan management of train components and better maintenance decision-making for high-speed trains.
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Hanmei Chen, Shaowen Hua, Zenghui Liu and Mei Zhang
The purpose of this paper is to investigate how audit fees change in responding to the financial crisis of 2008. It also examines auditors’ perceived risk and how they priced the…
Abstract
Purpose
The purpose of this paper is to investigate how audit fees change in responding to the financial crisis of 2008. It also examines auditors’ perceived risk and how they priced the risk in the financial crisis.
Design/methodology/approach
Using a sample of 20,930 firm-year observations, this paper examines the change of audit fees before, during and after the financial crisis, as well as the relationship between audit fees and restatements. Furthermore, this study investigates whether this relationship between audit fees and restatements strengthened during the financial crisis.
Findings
The paper finds that audit fees increase as a result of the macro-systemic risks from the crisis. It also finds that there is a significantly positive relationship between audit fees and restatements, which is a proxy of risk factors related to poor financial reporting quality and poor audit quality. However, the results show that there is no significant change of the fees–restatements relationship in the financial crisis period.
Research limitations/implications
The main limitation of this study is that no definite answer can be provided for the question that whether auditors believe that poor audit quality and audit failures are leading up to the financial crisis. The test rejects the alternative hypothesis. However, it does not necessarily prove the null hypothesis is true.
Originality/value
This paper contributes to the current literature by analyzing not only the impact of the financial crisis on audit fees, but also how the accounting profession views its own role in the financial crisis.
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Kristin R. Eschenfelder, Kalpana Shankar, Rachel D. Williams, Dorothea Salo, Mei Zhang and Allison Langham
The purpose of this paper is to report on how library and information science (LIS) as a field operationalizes the concept of organizational sustainability for managing digital…
Abstract
Purpose
The purpose of this paper is to report on how library and information science (LIS) as a field operationalizes the concept of organizational sustainability for managing digital resources, projects and infrastructures such as digital libraries and repositories over time. It introduces a nine dimensional framework for organizational sustainability in the digital cultural heritage community.
Design/methodology/approach
Content analysis of publications from three LIS databases (2000–2015).
Findings
Comparing the articles to the nine dimension framework shows that most LIS articles discuss technology, financial or management dimensions. Fewer articles describe disaster planning, assessment or policy dimensions.
Research limitations/implications
Three LIS databases might not include all relevant journals, conferences, white papers and other materials. The data set also did not include books; library management textbooks might include useful material on organizational sustainability. Claims about the prevalence of themes are subject to methodological limits of content analysis.
Practical implications
Organizations that steward digital collections need to be clear about what they mean when they are referring to organizational sustainability so that they can make appropriate decisions for future-proofing their collections. The analysis would also suggest for a greater need to consider the full range of dimensions of organizational sustainability.
Originality/value
By introducing a new nine dimensional framework of organizational sustainability the authors hope to promote more and better conversations within the LIS community about organizational sustainability. The authors hope these conversations will lead to productive action and improvements in the arrangements of people and work necessary to keep digital projects and services going over time, given ongoing challenges.
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Chunyun Zhang, Jie Mei, Yushuai Bai, Miao Cui, Haifeng Peng and X. W. Gao
The purpose of this study is to simultaneously determine the constitutive parameters and boundary conditions by solving inverse mechanical problems of power hardening…
Abstract
Purpose
The purpose of this study is to simultaneously determine the constitutive parameters and boundary conditions by solving inverse mechanical problems of power hardening elastoplastic materials in three-dimensional geometries.
Design/methodology/approach
The power hardening elastoplastic problem is solved by the complex variable finite element method in software ABAQUS, based on a three-dimensional complex stress element using user-defined element subroutine. The complex-variable-differentiation method is introduced and used to accurately calculate the sensitivity coefficients in the multiple parameters identification method, and the Levenberg–Marquardt algorithm is applied to carry out the inversion.
Findings
Numerical results indicate that the complex variable finite element method has good performance for solving elastoplastic problems of three-dimensional geometries. The inversion method is effective and accurate for simultaneously identifying multi-parameters of power hardening elastoplastic problems in three-dimensional geometries, which could be employed for solving inverse elastoplastic problems in engineering applications.
Originality/value
The constitutive parameters and boundary conditions are simultaneously identified for power hardening elastoplastic problems in three-dimensional geometries, which is much challenging in practical applications. The numerical results show that the inversion method has high accuracy, good stability, and fast convergence speed.
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Tieliu T. Yu and Miranda M. Zhang
This article discusses the intra‐industry trade (IIT) aspect of international trade. The authors focus primarily on the trade between the United States and the 15 newly…
Abstract
This article discusses the intra‐industry trade (IIT) aspect of international trade. The authors focus primarily on the trade between the United States and the 15 newly independent states of the former Soviet Union. Using data for these countries and the United States, this paper estimate the share of IIT of the 15 newly independent countries. The Pearson Product‐Moment Correlation and the Spearman's Rank Correlation Coefficients were employed to determine the relationship between the IIT share and the stages of economic development. The test of has been hypothesis was conducted to examine the significance of the relationship. As a result, the paper reveals that the IIT share is more closely related to GNP per capita than to the overall GNP, which suggests that GNP per capita may be a better measure of the stage of economic development.
Yazhou Wang, Dehong Luo, Xuelin Zhang, Zhitao Wang, Hui Chen, Xiaobo Zhang, Ningning Xie, Shengwei Mei, Xiaodai Xue, Tong Zhang and Kumar K. Tamma
The purpose of this paper is to design a simple and accurate a-posteriori Lagrangian-based error estimator is developed for the class of backward differentiation formula (BDF…
Abstract
Purpose
The purpose of this paper is to design a simple and accurate a-posteriori Lagrangian-based error estimator is developed for the class of backward differentiation formula (BDF) algorithms with variable time step size, and the adaptive time-stepping in BDF algorithms is demonstrated for efficient time-dependent simulations in fluid flow and heat transfer.
Design/methodology/approach
The Lagrange interpolation polynomial is used to predict the time derivative, and then the accurate primary result is obtained by the Gauss integral, which is applied to evaluate the local error. Not only the generalized formula of the proposed error estimator is presented but also the specific expression for the widely applied BDF1/2/3 is illustrated. Two essential executable MATLAB functions to implement the proposed error estimator are appended for practical applications. Then, the adaptive time-stepping is demonstrated based on the newly proposed error estimator for BDF algorithms.
Findings
The validation tests show that the newly proposed error estimator is accurate such that the effectivity index is always close to unity for both linear and nonlinear problems, and it avoids under/overestimation of the exact local error. The applications for fluid dynamics and coupled fluid flow and heat transfer problems depict the advantage of adaptive time-stepping based on the proposed error estimator for time-dependent simulations.
Originality/value
In contrast to existing error estimators for BDF algorithms, the present work is more accurate for the local error estimation, and it can be readily extended to practical applications in engineering with a few changes to existing codes, contributing to efficient time-dependent simulations in fluid flow and heat transfer.
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Srijana Baral and Bin Mei
The purpose of this study is to examine the return sensitivity of public farmland and timberland real estate investment trusts (REITs) to private-equity farmland, timberland and…
Abstract
Purpose
The purpose of this study is to examine the return sensitivity of public farmland and timberland real estate investment trusts (REITs) to private-equity farmland, timberland and real estate, long-term corporate bonds and large- and small-cap stocks. The study also examines time-dependent contributions of selected asset classes to farmland and timberland REIT volatility.
Design/methodology/approach
The authors use a multi-factor asset pricing model under a seemingly unrelated regression framework to evaluate farmland and timberland REIT returns, and a state-space model with the Kalman filter to evaluate the time-dependent contributors of farmland and timberland REIT volatility. The authors first perform orthogonalized regressions to obtain pure independent factors, and then decompose volatility into individual asset components.
Findings
Significant loadings on financial assets are found for both farmland and timberland REITs, suggesting that they are generally driven by some common state variables. Large-cap stocks are found to be the major contributor of farmland and timberland REIT volatility, despite some differing patterns over time.
Originality/value
Empirical analysis of farmland REIT is very scarce. The authors compare the risk-return characteristics of farmland and timberland REITs under a state-space framework with the Kalman filter. This study can improve the understanding of the roles of farmland and timberland REITs in a multi-asset portfolio.
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Mukesh Kumar, Joginder Singh, Sunil Kumar and Aakansha
The purpose of this paper is to design and analyze a robust numerical method for a coupled system of singularly perturbed parabolic delay partial differential equations (PDEs).
Abstract
Purpose
The purpose of this paper is to design and analyze a robust numerical method for a coupled system of singularly perturbed parabolic delay partial differential equations (PDEs).
Design/methodology/approach
Some a priori bounds on the regular and layer parts of the solution and their derivatives are derived. Based on these a priori bounds, appropriate layer adapted meshes of Shishkin and generalized Shishkin types are defined in the spatial direction. After that, the problem is discretized using an implicit Euler scheme on a uniform mesh in the time direction and the central difference scheme on layer adapted meshes of Shishkin and generalized Shishkin types in the spatial direction.
Findings
The method is proved to be robust convergent of almost second-order in space and first-order in time. Numerical results are presented to support the theoretical error bounds.
Originality/value
A coupled system of singularly perturbed parabolic delay PDEs is considered and some a priori bounds are derived. A numerical method is developed for the problem, where appropriate layer adapted Shishkin and generalized Shishkin meshes are considered. Error analysis of the method is given for both Shishkin and generalized Shishkin meshes.
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Xiaoyi He, Liping Li, Xiaojian Liu, Yongsheng Wu, Shujiang Mei and Zhen Zhang
Hand, foot and mouth disease (HFMD) is a common infectious disease in infants and children. HFMD has caused millions of cases and a large epidemic worldwide. A number of studies…
Abstract
Purpose
Hand, foot and mouth disease (HFMD) is a common infectious disease in infants and children. HFMD has caused millions of cases and a large epidemic worldwide. A number of studies have shown that the incidence of HFMD is closely related to various factors such as meteorological factors, environmental air pollution factors and socio-economic factors. However, there are few studies that systematically consider the impact of various factors on the incidence of HFMD. The paper aims to discuss these issues.
Design/methodology/approach
This study used grey correlation analysis and principal component analysis (PCA) method to systematically analyse the impact of meteorological factors, health resource factors, socio-economic factors and environmental air pollution factors on the incidence of HFMD in Shenzhen.
Findings
The incidence of HFMD in Shenzhen was affected by multiple factors. Grey correlation analysis found eight influencing factors which are as follows: volume of industrial waste gas emission; the days of air quality equal to or above grade; the volume of industrial nitrogen oxide emission; precipitation; the mean air temperature; the gross domestic product; the expenditure for medical and health care; and the gross domestic product per capita. PCA found that the gross domestic product, the volume of industrial soot emission, the relative humidity, and the days of air quality equal to or above grade have a higher load value.
Originality/value
This study is the one of the first studies that apply the grey correlation analysis to analyse the influencing factors of HFMD in the English literature, which to some extent fills up the blank in this field.