Abstract
Purpose
Nowadays, the breakout of the COVID-19 pandemic has caused an important change in teaching models. The emotional experience of this change has an important impact on online teaching. This paper aims to explore its time evolution characteristics and provide reference for the development of online teaching in the post epidemic era.
Design/methodology/approach
The article firstly crawls the online teaching-related comment text data on Zhihu platform and performs emotional calculation to obtain a one-dimensional time series of daily average emotional values. Then, by using non-linear time-series analysis, this paper reconstructs the daily average emotion value time series in high-dimensional phase space, calculates the maximum Lyapunov exponent and correlation dimension and finally, explores the feature patterns through recurrence plot and recurrence quantification analysis.
Findings
It was found that the sequence has typical non-linear chaotic characteristics; its correlation dimension indicates that it contains obvious fractal characteristics; the public emotional evolution shows a cyclical rise and fall. By text mining and temporal evolution analysis, this paper explores the evolution law over chronically of the daily average emotion value time series, provides feasible strategies to improve students' online learning experience and quality and continuously optimizes this new teaching model in the era of pandemic.
Originality/value
Based on social knowledge sharing platform of Q&A, this paper models and analyzes users interaction data under online teaching-related topics. This paper explores the evolution law over a long time period of the daily average emotion value time series using text mining and temporal evolution analysis. It then offers workable solutions to enhance the quality and experience of students' online learning, and it continuously improves this new teaching model in the age of pandemics.
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Junwei Zhang, Muhammad Naseer Akhtar, Yajun Zhang and Shan Sun
Drawing from cognitive and emotional perspectives, the purpose of this paper is to theorize and test a dual-pathway model in which moral disengagement and anger toward…
Abstract
Purpose
Drawing from cognitive and emotional perspectives, the purpose of this paper is to theorize and test a dual-pathway model in which moral disengagement and anger toward organization act as two explanatory mechanisms of the association between perceived overqualification and employee cyberloafing. The authors further proposed that the strengths of these two mediating mechanisms depend on employee moral identity.
Design/methodology/approach
The authors used hierarchical linear modeling to examine the hypotheses by analyzing a sample of 294 employees working in 71 departments in China.
Findings
Results revealed that moral disengagement and anger toward organization mediated the positive link between perceived overqualification and cyberloafing beyond the influence of social exchange. Furthermore, moral identity attenuated the association between the mediators (i.e. moral disengagement and anger) and cyberloafing and the indirect relationship between perceived overqualification and cyberloafing.
Originality/value
Extant studies have examined the effects of perceived overqualification on employee behaviors in terms of task performance, organizational citizenship behavior, proactive behavior, as well as withdrawal behavior. The study expands this line of research by empirically investigating whether and how perceived overqualification influences cyberloafing.
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Bill B. Francis, Iftekhar Hasan and Eric Ofori
This paper investigates the impact of the development of capital markets on economic growth in Africa and reports a significant increase in real GDP per capita after stock…
Abstract
This paper investigates the impact of the development of capital markets on economic growth in Africa and reports a significant increase in real GDP per capita after stock exchanges are established. This paper also reveals that there are significant improvements in the level of private investments in the post stock market launch era. The results also indicate that stock markets play a complementary role to the banking sector by contributing to the availability of private credit. Although African capital markets are relatively less advanced when compared to capital markets on other continents (particularly in terms of technology, structure, and liquidity), we find that their establishment has been crucial in helping African countries catch up with the rest of the world.
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Weijia Lu, Chengxi Zhang, Fei Liu, Jin Wu, Jihe Wang and Lining Tan
This paper aims to investigate the relative translational control for multiple spacecraft formation flying. This paper proposes an engineering-friendly, structurally simple, fast…
Abstract
Purpose
This paper aims to investigate the relative translational control for multiple spacecraft formation flying. This paper proposes an engineering-friendly, structurally simple, fast and model-free control algorithm.
Design/methodology/approach
This paper proposes a tanh-type self-learning control (SLC) approach with variable learning intensity (VLI) to guarantee global convergence of the tracking error. This control algorithm utilizes the controller's previous control information in addition to the current system state information and avoids complicating the control structure.
Findings
The proposed approach is model-free and can obtain the control law without accurate modeling of the spacecraft formation dynamics. The tanh function can tune the magnitude of the learning intensity to reduce the control saturation behavior when the tracking error is large.
Practical implications
This algorithm is model-free, robust to perturbations such as disturbances and system uncertainties, and has a simple structure that is very conducive to engineering applications.
Originality/value
This paper verified the control performance of the proposed algorithm for spacecraft formation in the presence of disturbances by simulation and achieved high steady-state accuracy and response speed over comparisons.
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Chengxi Zhang, Jin Wu, Ran Sun, Mingjiang Wang and Dechao Ran
The purpose of this paper is to study the general actuator modeling in spacecraft attitude control systems.
Abstract
Purpose
The purpose of this paper is to study the general actuator modeling in spacecraft attitude control systems.
Design/methodology/approach
The proposed module in this paper provides various non-ideal factors such as the second-order dynamic time response, time-delay, bias torques, dead-zones and saturation. The actuator module can make the simulation as close to the practical situation as possible.
Findings
This paper presents a practical integrated module for the simulation of attitude control algorithms. Based on theoretical modeling, we give simulation modules and numerical examples. The proposed model can be directly used in spacecraft control simulation. Instead of considering only a few of them, it makes the simulation more convincing. Though it may not be perfect, it is better than totally ignoring the actuator dynamics.
Originality/value
The authors provide an integrated actuator model for spacecraft attitude control simulation, considering as many nonlinear factors as possible once time.
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Abdullahil Mamun, Harun BAL and Emrah Eray AKCA
The study aims to examine the export-led growth (ELG) hypothesis for Bangladesh. The direction of causality between export and output largely determines the success of…
Abstract
Purpose
The study aims to examine the export-led growth (ELG) hypothesis for Bangladesh. The direction of causality between export and output largely determines the success of export-oriented trade policies. A unidirectional causality running from export to output growth is required according to the narrow definition, while bidirectional causality is allowed for the broader definition. The study offers the causality inference, both from narrow and broader senses.
Design/methodology/approach
The study uses the bootstrap version of Toda and Yamamoto-modified causality tests, a recent development in time series econometrics, robust against the regularity conditions such as stationarity, properties of integration and cointegration and constancy of parameters. It uses monthly secondary data for the period of 1990-2014.
Findings
Test results suggest a unidirectional positive causal relationship from exports to output growth, meaning that the policies and strategies supporting exports are promoting output growth and thereby approve the ELG hypothesis for Bangladesh from the narrow sense. However, the absence of bidirectional causality between export and output growth, necessary to support the ELG hypothesis from the broader perspective, discards the conjecture that output growth is reinvigorated through the probable second-round effects of ELG produced from output growth to exports.
Practical implications
Lower investments in infrastructure, technology and education are reasons for the absence of ELG from the broader sense. Therefore, directing returns generated from exports for the development of technology, infrastructure and human capital, with regular and continuous revision of trade-liberalization policies so as to make its exports more competitive in the world market, will help Bangladesh trigger the second-round effect of ELG produced from output growth to exports.
Originality/value
Beyond the conventional approaches, this is the first contemporary time series econometrics causality analysis between export and output growth of Bangladesh, both from narrow and broader senses.
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Xinghua Shan, Xiaoyan Lv, Jinfei Wu, Shuo Zhao and Junfeng Zhang
Revenue management (RM) is a significant technique to improve revenue with limited resources. With the macro environment of dramatically increasing transit capacity and rapid…
Abstract
Purpose
Revenue management (RM) is a significant technique to improve revenue with limited resources. With the macro environment of dramatically increasing transit capacity and rapid railway transport development in China, it is necessary to involve the theory of RM into the operation and decision of railway passenger transport.
Design/methodology/approach
This paper proposes the theory and framework of generalized RM of railway passenger transport (RMRPT), and the thoughts and methods of the main techniques in RMRPT, involving demand forecasting, line planning, inventory control, pricing strategies and information systems, are all studied and elaborated. The involved methods and techniques provide a sequential process to help with the decision-making for each stage of RMRPT. The corresponding techniques are integrated into the information system to support practical businesses in railway passenger transport.
Findings
The combination of the whole techniques devotes to railway benefit improvement and transit resource utilization and has been applied into the practical operation and organization of railway passenger transport.
Originality/value
The development of RMRPT would provide theoretical and technical support for the improvement of service quality as well as railway benefits and efficiency.
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Chengxi Zhang, Jin Wu, Yulong Huang, Yu Jiang, Ming-zhe Dai and Mingjiang Wang
Recent spacecraft attitude control systems tend to use wireless communication for cost-saving and distributed mission purposes while encountering limited communication resources…
Abstract
Purpose
Recent spacecraft attitude control systems tend to use wireless communication for cost-saving and distributed mission purposes while encountering limited communication resources and data exposure issues. This paper aims to study the attitude control problem with low communication frequency under the sampled-data.
Design/methodology/approach
The authors propose constructive control system structures based on quantization and event-triggered methods for intra-spacecraft and multi-spacecraft systems, and they also provide potential solutions to shield the control system's data security. The proposed control architectures can effectively save communication resources for both intra-spacecraft and multi-spacecraft systems.
Findings
The proposed control architectures no longer require sensors with trigger-ing mechanism and can achieve distributed control schemes. This paper also provides proposals of employing the public key encryption to secure the data in control-loop, which is transmitted by the event-triggered control mechanism.
Practical implications
Spacecraft attempts to use wireless communication, yet the attitude control system does not follow up promptly to accommodate these variations. Compared with existing approaches, the proposed control structures can save communication resources of control-loop in multi-sections effectively, and systematically, by rationally configuring the location of quantization and event-triggered mechanisms.
Originality/value
This paper presents several new control schemes and a necessary condition for the employment of encryption algorithms for control systems based on event-based communication.
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The purpose of this paper is to investigate the export‐led growth, growth‐led export, import‐led growth, growth‐led import and foreign deficit sustainability hypothesis in the…
Abstract
Purpose
The purpose of this paper is to investigate the export‐led growth, growth‐led export, import‐led growth, growth‐led import and foreign deficit sustainability hypothesis in the case of China, using annual time series data from 1978‐2009.
Design/methodology/approach
For estimation evidence this study employs the Phillips Perron unit root tests to examine the level of integration and the autoregressive distributed lag (ARDL) approach is employed to determine the long run relationship, and the direction of long run and short run causal relationship is examined by using modified Granger causality test.
Findings
The results confirm the bidirectional long run relationship between the economic growth and exports, economic growth and imports, and exports and imports. These findings guided the authors to conclude that the exports‐led growth, growth‐led exports, imports‐led growth and growth‐led imports hypothesis is valid, and foreign deficit is sustainable for China. The long run elasticities are as follows: the elasticity of economic growth with respect to exports is 0.591, and elasticity of exports with respect to economic growth is 1.635. The elasticity of economic growth with respect to imports is 0.621, and elasticity of imports with respect to economic growth is 1.392. Further more the elasticity of exports with respect to imports is 1.322, and imports elasticity with respect to exports is 0.975.
Originality/value
This study utilizes the relative new cointegration method of ARDL approach. The empirical findings of this study are vital for policy makers of China in the formulation of trade policies.