This chapter examines the limit properties of information criteria (such as AIC, BIC, and HQIC) for distinguishing between the unit-root (UR) model and the various kinds of…
Abstract
This chapter examines the limit properties of information criteria (such as AIC, BIC, and HQIC) for distinguishing between the unit-root (UR) model and the various kinds of explosive models. The explosive models include the local-to-unit-root model from the explosive side the mildly explosive (ME) model, and the regular explosive model. Initial conditions with different orders of magnitude are considered. Both the OLS estimator and the indirect inference estimator are studied. It is found that BIC and HQIC, but not AIC, consistently select the UR model when data come from the UR model. When data come from the local-to-unit-root model from the explosive side, both BIC and HQIC select the wrong model with probability approaching 1 while AIC has a positive probability of selecting the right model in the limit. When data come from the regular explosive model or from the ME model in the form of 1 + nα/n with α ∈ (0, 1), all three information criteria consistently select the true model. Indirect inference estimation can increase or decrease the probability for information criteria to select the right model asymptotically relative to OLS, depending on the information criteria and the true model. Simulation results confirm our asymptotic results in finite sample.
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Discrete element method (DEM) has been extensively used in the laboratory of particulate and multiphase processing at the University of New South Wales (UNSW) to study the…
Abstract
Discrete element method (DEM) has been extensively used in the laboratory of particulate and multiphase processing at the University of New South Wales (UNSW) to study the fundamentals of particulate matter at a particle scale. This paper briefly reviews the work in the laboratory, which covers the development of simulation techniques and their application to the study of particle packing and flow, transport properties and constitutive relationships of typical static or dynamic particulate systems. It is concluded, through representative comparison between simulated and measured results under different conditions, that DEM, as a major technique for discrete particle simulation, is an effective method for particle scale research of particulate matter.
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Chung-Gee Lin, Min-Teh Yu, Chien-Yu Chen and Pei-Hsuan Hsu
This chapter derives sentiment indicators (implied volatility and implied skewness) from the option pricing models of Corrado and Su (1996), Bakshi, Kapadia, and Madan (2003), and…
Abstract
This chapter derives sentiment indicators (implied volatility and implied skewness) from the option pricing models of Corrado and Su (1996), Bakshi, Kapadia, and Madan (2003), and Zhang, Zhen, Sun, and Zhao (2017), and then integrates these sentiment indicators with artificial intelligence deep neural network (AIDNN) for developing the behavioral finance AIDNN (BFAIDNN) algorithms. We apply the BFAIDNN algorithms to daily derivatives data of Taiwan Futures and Options markets from 2015 to 2017. Our results demonstrate that the trading strategies established by the BFAIDNN algorithms can generate positive rewards.
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Tian-Yu Wu, Jianfei Zhang, Yanjun Dai, Tao-Feng Cao, Kong Ling and Wen-Quan Tao
To present the detailed implementation processes of the IDEAL algorithm for two-dimensional compressible flows based on Delaunay triangular mesh, and compare the performance of…
Abstract
Purpose
To present the detailed implementation processes of the IDEAL algorithm for two-dimensional compressible flows based on Delaunay triangular mesh, and compare the performance of the SIMPLE and IDEAL algorithms for solving compressible problems. What’s more, the implementation processes of Delaunay mesh generation and derivation of the pressure correction equation are also introduced.
Design/methodology/approach
Programming completely in C++.
Findings
Five compressible examples are used to test the SIMPLE and IDEAL algorithms, and the comparison with measurement data shows good agreement. The IDEAL algorithm has much better performance in both convergence rate and stability over the SIMPLE algorithm.
Originality/value
The detail solution procedure of implementing the IDEAL algorithm for compressible flows based on Delaunay triangular mesh is presented in this work, seemingly first in the literature.
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Kangkang Yu, Jack Cadeaux, Ben Nanfeng Luo and Cheng Qian
This study aims to extend ambidexterity theory from the perspective of organisational learning and examine how process ambidexterity, which comprises operational flexibility and…
Abstract
Purpose
This study aims to extend ambidexterity theory from the perspective of organisational learning and examine how process ambidexterity, which comprises operational flexibility and operational routine, responds to environmental uncertainty and ultimately reduces organisational risks.
Design/methodology/approach
This study tests the hypotheses by analysing 464 annual reports of 115 listed companies in the Chinese agricultural and food industry using content and secondary data analyses. Four case studies are also provided.
Findings
The results show that (1) environmental uncertainty has a positive effect on either operational flexibility or operational routine; (2) both operational flexibility and operational routine have negative effects on organisational risks, supporting the view that process ambidexterity mediates the relationship between environmental uncertainty and organisational risks; and (3) organisational slack plays the role of “double-edged sword” by negatively moderating the effect of environmental uncertainty on operational flexibility and positively moderating the effect of environmental uncertainty on operational routine.
Originality/value
In an uncertain environment, companies are exposed to greater risk. This study contributes to risk management in three ways: first, it extends ambidexterity theory to process management and proposes how process ambidexterity balances operational flexibility and routines. Second, it distinguishes between the different conditions under which flexibility or routines are superior. Third, it explains the mechanisms related to how organisations can resolve environmental uncertainty into risk through process ambidexterity.
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Dong-Jin Lee, Grace B. Yu and M. Joseph Sirgy
The purpose of this paper is to reflect on the construct of phygital experiences and provide ideas that may spur future research on phygital consumer experiences in relation to…
Abstract
Purpose
The purpose of this paper is to reflect on the construct of phygital experiences and provide ideas that may spur future research on phygital consumer experiences in relation to consumer well-being using qualitative research methods.
Design/methodology/approach
With the increase in consumers’ online and offline interactions, there is a greater need for marketers to prompt integrated consumer experiences (i.e. integrated customer experiences through online and offline interactions). The authors developed this essay based on a literature review of phygital experiences and consumer well-being.
Findings
This commentary provides suggestions on how to expand the conceptual boundaries of phygital experiences by examining the effects of consumer phygital experiences in relation to consumer need satisfaction, consumer happiness and benefits to the firm. The commentary also includes several methodological suggestions that can guide future qualitative research.
Originality/value
The value of this commentary involves insights about research methods stimulated by the current research on consumer well-being.
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Zhangyu Wu, Hongfa Yu, Haiyan Ma, Bo Da and Yongshan Tan
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of…
Abstract
Purpose
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of different kinds of rebar in CASC exposed to simulated seawater for 0-270 d, the electrochemical techniques, including linear polarization resistance (LPR) technique and the electrochemical impedance spectroscopy (EIS), were used in the present work.
Design/methodology/approach
The electrochemical techniques, including LPR technique and the EIS, were used in the present work.
Findings
Based on the time-varying law of linear polarization curves, self-corrosion potential (Ecorr), polarization resistance (Rp), corrosion current density (Icorr), corrosion rate (i), and the characteristics of EIS diagrams for different types of rebar in CASC, it can be found that the anti-corrosion property of them can be ranked as epoxy resin coated steel > 2205 duplex stainless steel (2205S) > 316 L stainless steel (316 L) > organic coated steel > ordinary steel. Additionally, the linear regression equation between Rp and charge transfer resistance (Rct) was established. Finally, the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
Originality/value
The linear regression equation between polarization resistance and charge transfer resistance was established. And the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
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Qian Wang, Biao Ma, Liang Yu, Man Chen, Guoyu Wang and Liangjie Zheng
This paper aims to explore the influence of applied pressure on the tribological properties of the friction component in a wet multi-disc clutch during the running-in process.
Abstract
Purpose
This paper aims to explore the influence of applied pressure on the tribological properties of the friction component in a wet multi-disc clutch during the running-in process.
Design/methodology/approach
The running-in evolutionary was explored in terms of global friction performance. The variation of friction torque and mean COF of the initial 300 engagement cycles was obtained by full-scale tests. Finally, an optical microscope was used to detect the wear characteristics of friction surfaces.
Findings
The applied pressure showed a significant influence on the tribological behaviors of wet clutches during the running-in process. The mean COF decreased and then increases with the increase of the applied pressure. A higher applied pressure contributed to more asperity summits being sheared, thus resulting in a smoother surface. Considering a suitable wore performance, properly applied pressure is necessary.
Originality/value
The results provide theoretical guidance for selecting the optimal applied pressure in the running-in of wet clutches.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2022-0256/
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Yu Liu and Ziming Zeng
Previous research mainly uses graph neural networks on syntactic dependency graphs, often neglecting emotional cues in sarcasm detection and failing to integrate image features…
Abstract
Purpose
Previous research mainly uses graph neural networks on syntactic dependency graphs, often neglecting emotional cues in sarcasm detection and failing to integrate image features for multimodal information effectively. To address these limitations, this study proposes a novel multimodal sarcasm detection model based on the directed graph isomorphism network with sentiment enhancement and multimodal fusion (DGIN-SE-MF).
Design/methodology/approach
The approach extracts image and text features through vision transformer and BERT, respectively. To deeply integrate the extracted features, the author develops a text-guided multi-head attention fusion mechanism module. Subsequently, a directed graph is constructed through SE and the multimodal factorized bilinear pooling method to integrate image features into the graph. The DGIN then fuses the image and text features, using a weighted attention mechanism to generate the final representation.
Findings
The model is validated on three datasets: English, Chinese and an Indonesian–English dataset. The results demonstrate that the proposed model consistently outperforms other baseline models, particularly on the Chinese and English sarcasm datasets, achieving F1 scores of 88.75 % and 83.10 %, respectively.
Originality/value
The proposed model addresses the inadequacies of previous methods by effectively integrating emotional cues and image features into sarcasm detection. To the best of the authors’ knowledge, this is the first work to leverage a DGIN-SE-MF for this task, leading to significant improvements in detection performance across different languages.
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Siying Lin, Feng Yu and Zijun Zhou
In response to the challenges of maintaining the configuration and navigation stability of low-cost unmanned aerial vehicle swarms under intermittent global navigation satellite…
Abstract
Purpose
In response to the challenges of maintaining the configuration and navigation stability of low-cost unmanned aerial vehicle swarms under intermittent global navigation satellite system (GNSS) signal conditions, this study aims to introduce a fast network topology generation algorithm and a hybrid covariance filter.
Design/methodology/approach
First, using spatially stable structures and the principle of three-sphere intersection, connectivity between nodes is rapidly generated, ultimately forming a network topology with tetrahedrons as the basic unit. This ensures the stability of the configuration. Subsequently, a problem arises from the improper distribution of internal confidence within the system when some nodes are connected to GNSS, whereas others rely solely on ranging. In response, a hybrid covariance method with independent relative and absolute covariance matrices is proposed, which can improve the overall navigation precision of the swarm.
Findings
Simulation results show that the approach achieves rapid convergence of relative positioning errors to less than 0.5 m for internode distances over 100 m. When one, two and three anchor nodes are accessed, the positioning accuracy of the proposed method is improved by 31.59 %, 64.53 % and 64.48 %, respectively, compared with the existing methods.
Originality/value
The proposed method can stabilize configurations and improve overall positioning accuracy, providing support for addressing distributed navigation issues in intermittent GNSS signals.