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Article
Publication date: 11 June 2018

Bing Hua, Lin Chen, Yunhua Wu and Zhiming Chen

The three-axis simulator relies on the air film between the air bearing and the bearing seat to achieve weightlessness and the frictionless motion condition, which is…

Abstract

Purpose

The three-axis simulator relies on the air film between the air bearing and the bearing seat to achieve weightlessness and the frictionless motion condition, which is essential for simulating the micro-disturbance torque of a satellite in outer space. However, at the beginning of the experiment, the disturbance torque caused by the misalignment between the center of gravity of the simulator and the center of rotation of the bearing is the most important factor restricting the use of the space three-axis simulator. In order to solve this problem, it is necessary to set the balance adjustment system on the simulator to compensate the disturbance torque caused by the eccentricity. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, a study of L1 adaptive automatic balancing control method for micro satellite with motor without other actuators is proposed. L1 adaptive control algorithm adds the low-pass filter to the control law, which in a certain sense to reduce the high-frequency signal and speed up the response time of the controlled system. At the same time, by estimating the adaptive parameter uncertainty in object, the output error of the state predictor and the controlled object can be stabilized under Lyapunov condition, and the robustness of the system is also improved. The automatic balancing method of PID is also studied in this paper.

Findings

Through this automatic balancing mechanism, the gravity disturbance torque can be effectively reduced down to 10−6 Nm, and the automatic balancing time can be controlled within 7 s.

Originality/value

This paper introduces an automatic balancing mechanism. The experimental results show that the mechanism can greatly improve the convergence speed while guaranteeing the control accuracy, and ensuring the feasibility of the large angle maneuver of spacecraft three-axis simulator.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 11 no. 2
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 18 July 2018

Bing Hua, Zhiwen Zhang, Yunhua Wu and Zhiming Chen

The geomagnetic field vector is a function of the satellite’s position. The position and speed of the satellite can be determined by comparing the geomagnetic field vector…

Abstract

Purpose

The geomagnetic field vector is a function of the satellite’s position. The position and speed of the satellite can be determined by comparing the geomagnetic field vector measured by on board three-axis magnetometer with the standard value of the international geomagnetic field. The geomagnetic model has the disadvantages of uncertainty, low precision and long-term variability. Therefore, accuracy of autonomous navigation using the magnetometer is low. The purpose of this paper is to use the geomagnetic and sunlight information fusion algorithm to improve the orbit accuracy.

Design/methodology/approach

In this paper, an autonomous navigation method for low earth orbit satellite is studied by fusing geomagnetic and solar energy information. The algorithm selects the cosine value of the angle between the solar light vector and the geomagnetic vector, and the geomagnetic field intensity as observation. The Adaptive Unscented Kalman Filter (AUKF) filter is used to estimate the speed and position of the satellite, and the simulation research is carried out. This paper also made the same study using the UKF filter for comparison with the AUKF filter.

Findings

The algorithm of adding the sun direction vector information improves the positioning accuracy compared with the simple geomagnetic navigation, and the convergence and stability of the filter are better. The navigation error does not accumulate with time and has engineering application value. It also can be seen that AUKF filtering accuracy is better than UKF filtering accuracy.

Research limitations/implications

Geomagnetic navigation is greatly affected by the accuracy of magnetometer. This paper does not consider the spacecraft’s environmental interference with magnetic sensors.

Practical implications

Magnetometers and solar sensors are common sensors for micro-satellites. Near-Earth satellite orbit has abundant geomagnetic field resources. Therefore, the algorithm will have higher engineering significance in the practical application of low orbit micro-satellites orbit determination.

Originality/value

This paper introduces a satellite autonomous navigation algorithm. The AUKF geomagnetic filter algorithm using sunlight information can obviously improve the navigation accuracy and meet the basic requirements of low orbit small satellite orbit determination.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 11 no. 4
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 4 October 2018

Zhiming Chen, Lei Li, Yunhua Wu, Bing Hua and Kang Niu

On-orbit service technology is one of the key technologies of space manipulation activities such as spacecraft life extension, fault spacecraft capture, on-orbit debris…

Abstract

Purpose

On-orbit service technology is one of the key technologies of space manipulation activities such as spacecraft life extension, fault spacecraft capture, on-orbit debris removal and so on. It is known that the failure satellites, space debris and enemy spacecrafts in space are almost all non-cooperative targets. Relatively accurate pose estimation is critical to spatial operations, but also a recognized technical difficulty because of the undefined prior information of non-cooperative targets. With the rapid development of laser radar, the application of laser scanning equipment is increasing in the measurement of non-cooperative targets. It is necessary to research a new pose estimation method for non-cooperative targets based on 3D point cloud. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, a method based on the inherent characteristics of a spacecraft is proposed for estimating the pose (position and attitude) of the spatial non-cooperative target. First, we need to preprocess the obtained point cloud to reduce noise and improve the quality of data. Second, according to the features of the satellite, a recognition system used for non-cooperative measurement is designed. The components which are common in the configuration of satellite are chosen as the recognized object. Finally, based on the identified object, the ICP algorithm is used to calculate the pose between two frames of point cloud in different times to finish pose estimation.

Findings

The new method enhances the matching speed and improves the accuracy of pose estimation compared with traditional methods by reducing the number of matching points. The recognition of components on non-cooperative spacecraft directly contributes to the space docking, on-orbit capture and relative navigation.

Research limitations/implications

Limited to the measurement distance of the laser radar, this paper considers the pose estimation for non-cooperative spacecraft in the close range.

Practical implications

The pose estimation method for non-cooperative spacecraft in this paper is mainly applied to close proximity space operations such as final rendezvous phase of spacecraft or ultra-close approaching phase of target capture. The system can recognize components needed to be capture and provide the relative pose of non-cooperative spacecraft. The method in this paper is more robust compared with the traditional single component recognition method and overall matching method when scanning of laser radar is not complete or the components are blocked.

Originality/value

This paper introduces a new pose estimation method for non-cooperative spacecraft based on point cloud. The experimental results show that the proposed method can effectively identify the features of non-cooperative targets and track their position and attitude. The method is robust to the noise and greatly improves the speed of pose estimation while guarantee the accuracy.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 12 no. 1
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 21 December 2020

Wang Chen, Luo Wei and Wu Yuefei

This paper traces the incorporation of western educational histories in the development of normal-school curricula during the late Qing Dynasty and the Republic of China…

Abstract

Purpose

This paper traces the incorporation of western educational histories in the development of normal-school curricula during the late Qing Dynasty and the Republic of China (1901–1944). It uses publication networks to show how the study of comparative educational history facilitated the international circulation of knowledge in the teaching profession, and how the “uses” of educational history were shaped by larger geopolitical forces.

Design/methodology/approach

This paper analyzes the international exchange of texts between normal schools in China and Japan and, subsequently, between normal schools in China and the United States. A database of 107 publications in the field of western educational history that were adopted in China reveals specific patterns of textual citation, cross-reference, and canon-formation in the field of educational historiography.

Findings

With conclusions derived from a combination of social network analysis and clustering analysis, this paper identifies three broad stages in China's development of normal-school curricula in comparative educational history: “Japan as Teacher,” “transitional period” and “America as Teacher.”

Research limitations/implications

Statistical analysis can reveal citation and reference patterns but not readers' understanding of the deeper meaning of texts – in this case, textbooks on the subject of western educational history. In addition, the types of publications analyzed in this study are relatively limited, the articles on the history of education in journals have not become the main objects of this study.

Originality/value

This paper uses both quantitative and qualitative methods to uncover the transnational circulation of knowledge in the field of comparative educational history during its formative period in China.

Details

History of Education Review, vol. 50 no. 1
Type: Research Article
ISSN: 0819-8691

Keywords

Article
Publication date: 1 May 1999

Zhiming Zhang, Gary Ching, Chen Gong, John Moody and Wing Sun Liu

Major findings of a project, Investigating The Markets Of Denim Wear In Hong Kong And China, sponsored by Institute of Textiles and Clothing, Hong Kong Polytechnic…

Abstract

Major findings of a project, Investigating The Markets Of Denim Wear In Hong Kong And China, sponsored by Institute of Textiles and Clothing, Hong Kong Polytechnic University, are discussed. The project was conducted in Hong Kong and six other major cities in China, including Beijing, Shanghai, Guangzhou, Harbin, Xi'an and Chengdu. Total sample size was 3,623. Three aspects of denim wear consumption were investigated and are discussed in the paper: dressing habit of Chinese consumers in denim wear, their consumption pattern, and brand awareness. Based on the findings, marketing implications are discussed as well. This information should be of use to manufacturers and retailers of denim wear and denim products for more effective marketing.

Details

Research Journal of Textile and Apparel, vol. 3 no. 2
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 10 February 2022

Meng-Long Huo, Zhou Jiang, Zhiming Cheng and Adrian Wilkinson

Grounded in the job demands–resources (JD-R) theory, this study investigates how the difficulty in social distancing at work, resulting from the COVID-19 crisis, may lead…

Abstract

Purpose

Grounded in the job demands–resources (JD-R) theory, this study investigates how the difficulty in social distancing at work, resulting from the COVID-19 crisis, may lead to intention to quit and career regret and how and when these effects may be attenuated.

Design/methodology/approach

Three-wave survey data were collected from 223 frontline service workers in a large restaurant company during the COVID-19 crisis.

Findings

The results show that difficulty in social distancing reduced employees' work engagement, and consequently, increased their turnover intention and career regret. These relationships were moderated by external employability, such that the influence of difficulty in social distancing weakened as external employability increased.

Originality/value

Social distancing measures have been applied across the globe to minimize transmission of COVID-19. However, such measures create a new job demand for service workers who find it difficult to practice social distancing due to the high contact intensity of service delivery. This study identified personal resources that help service workers cope with the demand triggered by COVID-19.

Details

Journal of Service Theory and Practice, vol. 32 no. 2
Type: Research Article
ISSN: 2055-6225

Keywords

Article
Publication date: 18 November 2019

Guanying Huo, Xin Jiang, Zhiming Zheng and Deyi Xue

Metamodeling is an effective method to approximate the relations between input and output parameters when significant efforts of experiments and simulations are required…

Abstract

Purpose

Metamodeling is an effective method to approximate the relations between input and output parameters when significant efforts of experiments and simulations are required to collect the data to build the relations. This paper aims to develop a new sequential sampling method for adaptive metamodeling by using the data with highly nonlinear relation between input and output parameters.

Design/methodology/approach

In this method, the Latin hypercube sampling method is used to sample the initial data, and kriging method is used to construct the metamodel. In this work, input parameter values for collecting the next output data to update the currently achieved metamodel are determined based on qualities of data in both the input and output parameter spaces. Uniformity is used to evaluate data in the input parameter space. Leave-one-out errors and sensitivities are considered to evaluate data in the output parameter space.

Findings

This new method has been compared with the existing methods to demonstrate its effectiveness in approximation. This new method has also been compared with the existing methods in solving global optimization problems. An engineering case is used at last to verify the method further.

Originality/value

This paper provides an effective sequential sampling method for adaptive metamodeling to approximate highly nonlinear relations between input and output parameters.

Details

Engineering Computations, vol. 37 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 March 2002

Zhiming Zhang, Yi Li, Chen Gong and Haidong Wu

In this paper, the importance of product attributes of casual wear for Chinese consumers was investigated. Data were gathered from a questionnaire survey conducted in six…

3845

Abstract

In this paper, the importance of product attributes of casual wear for Chinese consumers was investigated. Data were gathered from a questionnaire survey conducted in six cities of China. A total of 15 attributes were identified, and it was found that fit, comfort, style, color and workmanship were the most important attributes for Chinese consumers. It was also found that geographic and demographic factors had impacts on the importance of these attributes. These 15 attributes could be grouped into four factors, which may indicate a simplified process in information processing on the attributes by Chinese consumers. Marketing implication of the results was also discussed.

Details

Journal of Fashion Marketing and Management: An International Journal, vol. 6 no. 1
Type: Research Article
ISSN: 1361-2026

Keywords

Article
Publication date: 3 May 2016

Hong Men, Bin Sun, Xiao Zhao, Xiujie Li, Jingjing Liu and Zhiming Xu

The purpose of this study is to analyze the corrosion behavior of 304SS in three kinds of solution, 3.5 per cent NaCl, 5 per cent H2SO4 and 1 M (1 mol/L) NaOH, using…

Abstract

Purpose

The purpose of this study is to analyze the corrosion behavior of 304SS in three kinds of solution, 3.5 per cent NaCl, 5 per cent H2SO4 and 1 M (1 mol/L) NaOH, using electrochemical noise.

Design/methodology/approach

Corrosion types and rates were characterized by spectrum and time-domain analysis. EN signals were evaluated using a novel method of phase space reconstruction and chaos theory. To evaluate the chaotic characteristics of corrosion systems, the delay time was obtained by the mutual information method and the embedding dimension was obtained by the average false neighbors method.

Findings

The varying degrees of chaos in the corrosion systems were indicated by positive largest Lyapunov exponents of the electrochemical potential noise.

Originality/value

The change of correlation dimension in three kinds of solution demonstrated significant differences, clearly differentiating various types of corrosion.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 25 January 2021

Lijuan Luo, Siqi Duan, Shanshan Shang and Yu Pan

The reviews submitted by users are the foundation of user-generated content (UGC) platforms. However, the rapid growth of users brings the problems of information overload…

Abstract

Purpose

The reviews submitted by users are the foundation of user-generated content (UGC) platforms. However, the rapid growth of users brings the problems of information overload and spotty content, which makes it necessary for UGC platforms to screen out reviews that are really helpful to users. The authors put forward in this paper the factors influencing review helpfulness voting from the perspective of review characteristics and reviewer characteristics.

Design/methodology/approach

This study uses 8,953 reviews from 20 movies listed on Douban.com with variables focusing on review characteristics and reviewer characteristics that affect review helpfulness. To verify the six hypotheses proposed in the study, Stata 14 was used to perform tobit regression.

Findings

Findings show that review helpfulness is significantly influenced by the length, valence, timeliness and deviation rating of the reviews. The results also underlie that a review submitted by a reviewer who has more followers and experience is more affected by review characteristics.

Originality/value

Previous literature has discussed the factors that affect the helpfulness of reviews; however, the authors have established a new model that explores more comprehensive review characteristics and the moderating effect reviewer characteristics have on helpfulness. In this empirical research, the authors selected a UGC community in China as the research object. The UGC community may encourage users to write more helpful reviews by highlighting the characteristics of users. Users in return can use this to establish his/her image in the community. Future research can explore more variables related to users.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-05-2020-0186.

Details

Online Information Review, vol. 45 no. 3
Type: Research Article
ISSN: 1468-4527

Keywords

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