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Article
Publication date: 19 September 2016

Ziqiang Cui, Qi Wang, Qian Xue, Wenru Fan, Lingling Zhang, Zhang Cao, Benyuan Sun, Huaxiang Wang and Wuqiang Yang

Electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) are promising techniques for multiphase flow measurement due to their high speed, low…

Abstract

Purpose

Electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) are promising techniques for multiphase flow measurement due to their high speed, low cost, non-invasive and visualization features. There are two major difficulties in image reconstruction for ECT and ERT: the “soft-field”effect, and the ill-posedness of the inverse problem, which includes two problems: under-determined problem and the solution is not stable, i.e. is very sensitive to measurement errors and noise. This paper aims to summarize and evaluate various reconstruction algorithms which have been studied and developed in the word for many years and to provide reference for further research and application.

Design/methodology/approach

In the past 10 years, various image reconstruction algorithms have been developed to deal with these problems, including in the field of industrial multi-phase flow measurement and biological medical diagnosis.

Findings

This paper reviews existing image reconstruction algorithms and the new algorithms proposed by the authors for electrical capacitance tomography and electrical resistance tomography in multi-phase flow measurement and biological medical diagnosis.

Originality/value

The authors systematically summarize and evaluate various reconstruction algorithms which have been studied and developed in the word for many years and to provide valuable reference for practical applications.

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Article
Publication date: 19 June 2017

Qi Wang, Pengcheng Zhang, Jianming Wang, Qingliang Chen, Zhijie Lian, Xiuyan Li, Yukuan Sun, Xiaojie Duan, Ziqiang Cui, Benyuan Sun and Huaxiang Wang

Electrical impedance tomography (EIT) is a technique for reconstructing the conductivity distribution by injecting currents at the boundary of a subject and measuring the…

Abstract

Purpose

Electrical impedance tomography (EIT) is a technique for reconstructing the conductivity distribution by injecting currents at the boundary of a subject and measuring the resulting changes in voltage. Image reconstruction for EIT is a nonlinear problem. A generalized inverse operator is usually ill-posed and ill-conditioned. Therefore, the solutions for EIT are not unique and highly sensitive to the measurement noise.

Design/methodology/approach

This paper develops a novel image reconstruction algorithm for EIT based on patch-based sparse representation. The sparsifying dictionary optimization and image reconstruction are performed alternately. Two patch-based sparsity, namely, square-patch sparsity and column-patch sparsity, are discussed and compared with the global sparsity.

Findings

Both simulation and experimental results indicate that the patch based sparsity method can improve the quality of image reconstruction and tolerate a relatively high level of noise in the measured voltages.

Originality/value

EIT image is reconstructed based on patch-based sparse representation. Square-patch sparsity and column-patch sparsity are proposed and compared. Sparse dictionary optimization and image reconstruction are performed alternately. The new method tolerates a relatively high level of noise in measured voltages.

Details

Sensor Review, vol. 37 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 21 September 2015

Hailing Hou, Shihong Yue, Xiaoguang Huang and Huaxiang Wang

This paper aims to discuss flow pattern transition (FPT) as an important factor in multiple-phase flow measurements. Several methods have been proposed to control FPT, but…

Abstract

Purpose

This paper aims to discuss flow pattern transition (FPT) as an important factor in multiple-phase flow measurements. Several methods have been proposed to control FPT, but those methods fail to address the many issues in complex flow conditions that can affect flow patterns.

Design/methodology/approach

In this paper, a non-intrusive sensor instrumentation is applied to extract measurable data under different flow conditions. Using these data, a simple theoretical–mathematical method along with an orthogonal design is applied to FPT optimization. Orthogonal experiments are designed and carried out according to theoretical guidelines. Three selected process parameters – phase fraction, gas pressure in the initial independent process and liquid speed – are optimized for FPT results to produce a minimum FPT time.

Findings

The following results are obtained: the phase fraction in the initial independent process can lead to significant reductions in FPT time, gas pressure plays an important role and liquid speed has no apparent effect on FPT results. Under optimized conditions, FPT time can be shortened to 0.3-0.6 times by controlling the above three parameters compared with normal conditions.

Originality/value

The proposed method is simple, rapid and efficient for evaluating an FPT process and lays the foundation for further FPT applications.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 20 March 2018

Dongming Kong

The purpose of this paper is to test a catering theory by examining impacts of minority shareholders’ pressures on earnings management (EM), and attempt to answer: what is…

Abstract

Purpose

The purpose of this paper is to test a catering theory by examining impacts of minority shareholders’ pressures on earnings management (EM), and attempt to answer: what is the role of minority shareholders participation (MSP) in corporate governance? and does MSP serve as an external monitor to managers, or does it put excessive pressure on them?

Design/methodology/approach

Using a novel online voting data set in China’s stock market, the author constructs the measure of MSP, and regress the EM on MSP. To address the endogeneity, the author introduces propensity score matching and difference-in-difference methods, instrumental variables, and Heckman estimation to show that the results are robust to different specifications and alternative measures.

Findings

The author documents that: MSP plays limited role in external monitoring; and firms facing high MSP levels tend to manage earnings more actively. In addition, information asymmetry, proposals’ importance, managerial incentives, and CEO financial expertise significantly affect firms’ catering behaviors.

Originality/value

This paper contributes to different strands of the literature. First, the finding significantly supports the catering hypothesis from a new perspective of EM. Second, the author contributes to a hotly debated issue in corporate governance: whether minority shareholders should be granted increased participation in corporate decisions? The results also provide timely empirical evidence for government regulators who are concerned about the costs and benefits of granting minority shareholders direct control over corporate decisions.

Details

China Finance Review International, vol. 9 no. 1
Type: Research Article
ISSN: 2044-1398

Keywords

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Article
Publication date: 25 September 2018

Zhe Sun

The purpose of this paper is to unpack the black box of post-merger and acquisition (M&A) integration of reverse M&A by Chinese multinational enterprises (MNEs).

Abstract

Purpose

The purpose of this paper is to unpack the black box of post-merger and acquisition (M&A) integration of reverse M&A by Chinese multinational enterprises (MNEs).

Design/methodology/approach

This research adopts multiple cases of Chinese reverse M&A. Data are collected using the approaches of in-depth interviews, storytelling and narratives.

Findings

This research identifies various antecedents underlying Chinese post-M&A integration, such as asymmetries in resources, capabilities, vision and status between Chinese MNEs and acquired firms. The post-M&A integration process of Chinese reverse M&A consists of a top-down effortless integration initiated by Chinese MNEs with both benefits and problems, and a bottom-up reverse integration conducted by acquired firms.

Originality/value

By linking the pre-M&A phase and the post-M&A phase, this research builds a new model of post-M&A integration of Chinese reverse M&A from an indigenous Wu Wei paradigm. The new model counterpoises extant literature, shifting from the task and efficiency-focussed view to the people and harmony-focussed view.

Details

Chinese Management Studies, vol. 12 no. 4
Type: Research Article
ISSN: 1750-614X

Keywords

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