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Article
Publication date: 10 October 2023

Zhaoying Lu and Hisashi Tanizaki

This study aims to investigate how the gold return and its volatility respond to the COVID-19 pandemic.

102

Abstract

Purpose

This study aims to investigate how the gold return and its volatility respond to the COVID-19 pandemic.

Design/methodology/approach

Stochastic volatility (SV) models are conducted to examine the response of gold to the number of new confirmed cases and deaths.

Findings

The results indicate that an increase in the change rate of the number of COVID-19 infections or fatalities leads to heightened volatility in gold prices. Moreover, the results suggest that gold volatility is more sensitive to the impacts from high-income countries than by those from middle- and low-income countries. In addition, the asymmetric effect is detected in the gold price volatility, which is contrary to the typical asymmetric effect seen in the stock market. Furthermore, the results remain robust after accounting for the US dollar and the volatility index in relation to gold returns.

Practical implications

This study presents whether and to what extent gold is incorporated in the information related to the number of COVID-19 cases and deaths.

Originality/value

This study augments the existing literature by exploring how the number of COVID-19 infections and fatalities influences gold prices. In addition, it examines the day-of-the-week and asymmetric effects that may contribute to the volatility of gold prices. To the best of the authors’ knowledge, the evolution of gold has not yet been investigated using SV models.

Details

Studies in Economics and Finance, vol. 40 no. 5
Type: Research Article
ISSN: 1086-7376

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Article
Publication date: 20 February 2025

Ying Zhao, Tao Zhang, Jie Xu, Jie Yang and Wen-Ze Wu

This study aims to design a novel seasonal discrete grey model for forecasting monthly natural gas consumption by incorporating damping accumulation and time-polynomial term.

0

Abstract

Purpose

This study aims to design a novel seasonal discrete grey model for forecasting monthly natural gas consumption by incorporating damping accumulation and time-polynomial term.

Design/methodology/approach

Considering the principle of new information priority and nonlinear patterns in the original series of monthly natural gas consumption, we establish a novel discrete seasonal grey model by adding the damping accumulation and time-polynomial term into the existing model. In addition, the order of damping accumulation and the coefficient of time-power term can be determined by the moth flame optimization (MFO) algorithm.

Findings

The empirical cases show that the proposed model has a better prediction performance when compared with other benchmark models, including six seasonal grey models, one statistical model and one artificial intelligent model. Based on forecasts, the proposed model can be considered a promising tool for monthly natural gas consumption (NGC) in US.

Originality/value

By combining the damping accumulation and the time-polynomial term, a new discrete seasonal grey model for improving the prediction performance of the existing grey model is proposed. The properties of the proposed model are given, and the newly-designed model is initially applied to predict monthly NGC in US.

Details

Grey Systems: Theory and Application, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2043-9377

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Article
Publication date: 8 August 2018

Hao Yin, Yun Wan, Jinjun Zhou, Dewen Sun, Bo Li and Qianping Ran

The purpose of this study is to prepare a new self-emulsified waterborne epoxy hardener which can emulsify the liquid epoxy resin in aqueous media without addition of acid…

367

Abstract

Purpose

The purpose of this study is to prepare a new self-emulsified waterborne epoxy hardener which can emulsify the liquid epoxy resin in aqueous media without addition of acid neutralizers.

Design/methodology/approach

Two synthetic steps were adopted to prepare novel self-emulsified amine-epoxy adduct type hardener composition based on the reaction of a commercially available polyetheramine, bisphenol A epoxy resin and triethylene tetramine. The different factors affecting the synthesis of the waterborne epoxy hardener were explored by emulsifying and curing properties. The process and products were analyzed and confirmed by FIRT.

Findings

Compared to an introduction of polyether as a hydrophilic segment in previous literature, whose reaction required Lewis acid catalysts and strict control of the presence of water, the introduction of polyetheramine to obtain a novel self-emulsified waterborne epoxy hardener were concise and convenient by mere two amine-epoxy addition steps in this research. Moreover, the final product offered good film formation with a practical value of mechanical properties, glass transition temperature and water-resistant property.

Practical implications

The self-emulsified waterborne epoxy hardener can be used to prepare water-resistant waterborne coatings from liquid epoxy resins while also providing the option of zero VOC formulations.

Originality/value

Introduction of hydrophilic polyether amine to prepare self-emulsified waterborne epoxy hardener without acid neutralizers has not been systematically studied previously.

Details

Pigment & Resin Technology, vol. 48 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 14 October 2019

Iwin Thanakumar Joseph S., Sasikala J. and Sujitha Juliet D.

The purpose of this paper is to study various ship detection methodologies. The accuracy of ship detection using satellite images still suffers from disturbances due to cluttered…

225

Abstract

Purpose

The purpose of this paper is to study various ship detection methodologies. The accuracy of ship detection using satellite images still suffers from disturbances due to cluttered scenes and varying ship sizes. The suitability of the techniques for various applications is explained in this survey.

Design/methodology/approach

A list of data on the subject was gathered and processed into tables. The test outcomes were then discussed to determine the most effective ship detection technique under various complex environments.

Findings

In this work, the advantages and disadvantages of different classification techniques of ship detection are highlighted. The suitability of the techniques for various applications is also explained in this survey. Several hybrid approaches can be developed in order to increase the accuracy of ship detection system. This survey also aids in highlighting the significant contributions of satellite images to effective ship detection system.

Originality/value

In this paper, studying various ship detection methodologies is given specific attention. A survey on ship detection and recognition is clarified with the detailed comparative analysis of various classifier techniques.

Details

International Journal of Intelligent Unmanned Systems, vol. 7 no. 4
Type: Research Article
ISSN: 2049-6427

Keywords

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