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2,686 Results Found

  • Article
  • Open Access
3 Citations
3,505 Views
16 Pages

22 July 2024

The extent of correlation or co-movement among the returns of developed and emerging stock markets remains pivotal for efficiently diversifying global portfolios. This correlation is prone to variation over time as a consequence of escalating economi...

  • Article
  • Open Access
1,656 Views
19 Pages

29 January 2024

The transient responses of distributed energy resources (DERs) in a microgrid are dynamically correlated in spatial and temporal dimensions. Hence, the transient stability prediction in microgrids would require an effective modeling of time-varying c...

  • Article
  • Open Access
3 Citations
9,819 Views
29 Pages

Forecasting correlations between stocks and commodities is important for diversification across asset classes and other risk management decisions. Correlation forecasts are affected by model uncertainty, the sources of which can include uncertainty a...

  • Article
  • Open Access
1 Citations
3,356 Views
41 Pages

A Parsimonious Test of Constancy of a Positive Definite Correlation Matrix in a Multivariate Time-Varying GARCH Model

  • Jian Kang,
  • Johan Stax Jakobsen,
  • Annastiina Silvennoinen,
  • Timo Teräsvirta and
  • Glen Wade

We construct a parsimonious test of constancy of the correlation matrix in the multivariate conditional correlation GARCH model, where the GARCH equations are time-varying. The alternative to constancy is that the correlations change deterministicall...

  • Article
  • Open Access
3 Citations
2,726 Views
19 Pages

A Structural Reliability Analysis Method Considering Multiple Correlation Features

  • Xiaoning Bai,
  • Yonghua Li,
  • Dongxu Zhang and
  • Zhiyang Zhang

21 March 2024

The paper analyzes the correlation features between stress strength, multiple failure mechanisms, and multiple components. It investigates the effects of different correlation features on reliability and proposes a method for structural reliability a...

  • Article
  • Open Access
1 Citations
1,492 Views
18 Pages

25 June 2024

When a target moves at hypersonic speed, the aerodynamic thermal effect will cause air molecules to form a plasma sheath that envelopes the outer surface of the target, which consists of a large number of charged particles. The plasma sheath imposes...

  • Article
  • Open Access
2 Citations
2,428 Views
11 Pages

Risk Appetite and Jumps in Realized Correlation

  • Riza Demirer,
  • Konstantinos Gkillas,
  • Christos Kountzakis and
  • Amaryllis Mavragani

21 December 2020

This paper examines the role of non-cash flow factors over correlation jumps in financial markets. Utilizing time-varying risk aversion measure as a proxy for investor sentiment and the cross-quantilogram method applied to intraday data, we show that...

  • Article
  • Open Access
Energies2026, 19(3), 614;https://doi.org/10.3390/en19030614 
(registering DOI)

24 January 2026

This paper proposes a coordinated capacity configuration method for Virtual Power Plant (VPP) distributed resources that considers time-varying power coupling. The method addresses the inadequate economic efficiency and reliability of existing config...

  • Article
  • Open Access
1 Citations
2,242 Views
23 Pages

Beneath the Surface: Disentangling the Dynamic Network of the U.S. and BRIC Stock Markets’ Interrelations Amidst Turmoil

  • Neenu Chalissery,
  • T. Mohamed Nishad,
  • J. A. Naushad,
  • Mosab I. Tabash and
  • Mujeeb Saif Mohsen Al-Absy

13 December 2024

The study examines the time-varying correlation and return spillover mechanism among developed (U.S.) and emerging (BRIC) stock markets during major crises from 2000 to 2023, namely the global financial crisis, COVID-19, and the Russia–Ukraine...

  • Article
  • Open Access
15 Citations
3,967 Views
18 Pages

In the Dynamic Conditional Correlation with Mixed Data Sampling (DCC-MIDAS) framework, we scrutinize the correlations between the macro-financial environment and CO2 emissions in the aftermath of the COVID-19 diffusion. The main original idea is that...

  • Article
  • Open Access
1 Citations
3,819 Views
30 Pages

This study contributes to the ongoing debate on the size effect and size-based investment styles by investigating the return and volatility spillovers and time-varying conditional correlations among Saudi large-, mid-, and small-cap indices. To this...

  • Article
  • Open Access
13 Citations
4,362 Views
23 Pages

26 January 2018

In this study, we proposed a new empirical method by combining generalized autoregressive score functions and a copula model with high-frequency data to model the conditional time-varying joint distribution of the government bond yields between Polan...

  • Article
  • Open Access
516 Views
15 Pages

27 November 2025

Although greenhouse microclimates typically exhibit gradual and near-linear transitions, abrupt fluctuations in external weather conditions and actuator operations introduce nonlinear dynamics that complicate accurate interpretation and prediction. P...

  • Article
  • Open Access
27 Citations
7,189 Views
20 Pages

Do Tense Geopolitical Factors Drive Crude Oil Prices?

  • Fen Li,
  • Zhehao Huang,
  • Junhao Zhong and
  • Khaldoon Albitar

18 August 2020

Geopolitical factors are considered a crucial factor that makes a difference in crude oil prices. Over the last three decades, many political events occurred frequently, causing short-term fluctuations in crude oil prices. This paper aims to examine...

  • Article
  • Open Access
2,005 Views
9 Pages

14 July 2022

In this study, a modified non-stationary geometry-based scattering model for tunnel vehicle-to-vehicle (V2V) multiple-input multiple-output Ricean fading channels is presented. The proposed channel introduces non-line-of-sight three-dimensional multi...

  • Article
  • Open Access
1 Citations
5,885 Views
26 Pages

Amid the growing debate over how cryptocurrencies are reshaping global finance, this study explores the nexus between Bitcoin, Brent Crude Oil, Gold and the U.S. Dollar Index. We used a time-varying vector autoregressive (tvVAR) model to examine the...

  • Article
  • Open Access
6 Citations
2,731 Views
14 Pages

Noise Cancellation Method Based on TVF-EMD with Bayesian Parameter Optimization

  • Miaomiao Yu,
  • Hongyong Yuan,
  • Kaiyuan Li and
  • Lizheng Deng

12 June 2023

To separate the noise and important signal features of the indoor carbon dioxide (CO2) concentration signal, we proposed a noise cancellation method, based on time-varying, filtering-based empirical mode decomposition (TVF-EMD) with Bayesian optimiza...

  • Article
  • Open Access
5 Citations
3,765 Views
16 Pages

16 May 2021

This study investigates the daily co-movements in commodity prices over the period 2006–2020 using a novel approach based on a time-varying Gerber correlation. The statistic is computed considering a set of probabilities estimated via non-traditional...

  • Article
  • Open Access
13 Citations
17,454 Views
27 Pages

This article undertakes a literature review on the topic of market integration, covering over 380 articles from the 1980s to 2024. The review consists of a qualitative analysis for context and a quantitative analysis for content, identifying key rese...

  • Article
  • Open Access
3 Citations
4,077 Views
37 Pages

This paper proposes a methodology for building Multivariate Time-Varying STCC–GARCH models. The novel contributions in this area are the specification tests related to the correlation component, the extension of the general model to allow for a...

  • Article
  • Open Access
4 Citations
1,559 Views
13 Pages

A Three-Dimensional Time-Varying Channel Model for THz UAV-Based Dual-Mobility Channels

  • Kai Zhang,
  • Fenglei Zhang,
  • Yongjun Li,
  • Xiang Wang,
  • Zhaohui Yang,
  • Yuanhao Liu,
  • Changming Zhang and
  • Xin Li

30 October 2024

Unmanned aerial vehicle (UAV) as an aerial base station or relay device is a promising technology to rapidly provide wireless connectivity to ground device. Given UAV’s agility and mobility, ground user’s mobility, a key question is how t...

  • Article
  • Open Access
57 Citations
6,821 Views
18 Pages

4 October 2017

This paper explores the potential diversification benefits of socially responsible investments for conventional stock portfolios by examining the risk spillovers and dynamic correlations between conventional and sustainability stock indexes from a nu...

  • Article
  • Open Access
543 Views
25 Pages

A Dual-Layer Optimal Operation of Multi-Energy Complementary System Considering the Minimum Inertia Constraint

  • Houjian Zhan,
  • Yiming Qin,
  • Xiaoping Xiong,
  • Huanxing Qi,
  • Jiaqiu Hu,
  • Jian Tang and
  • Xiaokun Han

30 September 2025

The large-scale utilization of wind and solar energy is crucial for achieving carbon neutrality targets. However, as extensive wind and solar power generation is integrated via power electronic devices, the inertia level of power systems continues to...

  • Feature Paper
  • Article
  • Open Access
10 Citations
18,533 Views
13 Pages

Using DCC-GARCH model, this paper finds that, since 1990, the relationship between crude oil prices and the US dollar index is time-varying, demonstrating a process of ‘very weak correlation—negative correlation—enhanced negative co...

  • Article
  • Open Access
10 Citations
21,563 Views
15 Pages

The main aim of this paper is to examine the dynamic relationship between the three pillars of the economy: unemployment, inflation, and GDP in Ethiopia using the cross-wavelet transform (XWT) analysis, the multivariate Student-t generalized autoregr...

  • Article
  • Open Access
39 Citations
6,817 Views
22 Pages

An Improved VMD-LSTM Model for Time-Varying GNSS Time Series Prediction with Temporally Correlated Noise

  • Hongkang Chen,
  • Tieding Lu,
  • Jiahui Huang,
  • Xiaoxing He,
  • Kegen Yu,
  • Xiwen Sun,
  • Xiaping Ma and
  • Zhengkai Huang

24 July 2023

GNSS time series prediction plays a significant role in monitoring crustal plate motion, landslide detection, and the maintenance of the global coordinate framework. Long short-term memory (LSTM) is a deep learning model that has been widely applied...

  • Article
  • Open Access
1 Citations
2,370 Views
16 Pages

7 February 2024

In this work, an advanced 2D nonparametric correlogram method is presented to cope with output-only measurements of linear (slow) time-varying systems. The proposed method is a novel generalization of the kernel function-based regularization techniqu...

  • Article
  • Open Access
2,049 Views
15 Pages

This study examines the daily top 100 cryptocurrencies on Uniswap V3. It denoises the correlation coefficient matrix of cryptocurrencies by using sliding window techniques and random matrix theory. Further, this study constructs a time-varying correl...

  • Article
  • Open Access
583 Views
16 Pages

5 November 2025

Time-varying wind conditions, on which wind turbines depend, significantly influence power generation performance. Accordingly, this study proposes an approach to improve the accuracy of wind power generation prediction by incorporating time-varying...

  • Article
  • Open Access
14 Citations
4,935 Views
18 Pages

Sustainability of Global Economic Policy and Stock Market Returns in Indonesia

  • Shabir Mohsin Hashmi,
  • Muhammad Akram Gilal and
  • Wing-Keung Wong

12 May 2021

Interdependence in trade and financial globalization has increased the vulnerability of developed and developing countries to external shocks alike, whereas emerging markets are more vulnerable to the shocks originating from the world’s leading econo...

  • Article
  • Open Access
1 Citations
1,520 Views
20 Pages

10 December 2023

Time-varying reliability models of multi-cracked beam structures are established in this paper, which provide a theoretical method for the safety evaluation of multi-cracked beam structures. The reliability models proposed in this paper consider the...

  • Article
  • Open Access
7 Citations
2,106 Views
16 Pages

25 June 2023

Reliability-based robust design methods have been widely used in the field of product design; however, they are difficult to apply to the fatigue reliability design process of rolling bearings due to the problems of determining fatigue accumulated da...

  • Article
  • Open Access
12 Citations
3,529 Views
16 Pages

Vibration Characteristics of Corn Combine Harvester with the Time-Varying Mass System under Non-Stationary Random Vibration

  • Yanchun Yao,
  • Xiaoke Li,
  • Zihan Yang,
  • Liang Li,
  • Duanyang Geng,
  • Peng Huang,
  • Yongsheng Li and
  • Zhenghe Song

21 November 2022

In field harvesting conditions, the non-stationary random vibration characteristics of the harvester are rarely considered, and the results of vibration frequency calculated by different time–frequency transformation methods are different. In t...

  • Article
  • Open Access
9 Citations
2,584 Views
20 Pages

26 February 2022

Rolling bearings are critical to the normal operation of mechanical systems, which often undergo time-varying working conditions. When the local defects appear on a rolling bearing, the transient impulses will generate and be covered by the strong ba...

  • Article
  • Open Access
8 Citations
2,165 Views
17 Pages

Modeling and Characterization of Complex Dynamical Properties of Railway Ballast

  • Xia Hua,
  • Wael Zatar,
  • Xiangle Cheng,
  • Gang S. Chen,
  • Yini She,
  • Xiaotian Xu and
  • Zhicheng Liao

2 December 2024

The nonlinear mechanical properties of ballasted tracks along railways result in complex dynamics of the vehicle–track systems. Employing localized characterization of ballast and a simplified model might underestimate the vehicle–track s...

  • Article
  • Open Access
5 Citations
2,050 Views
24 Pages

3 October 2023

The relationship between foreign exchange rates and crude oil prices holds significant importance in comprehending the dynamics of oil markets and their implications for diverse economies. This study utilizes the time-varying copula to examine the in...

  • Article
  • Open Access
3 Citations
1,647 Views
15 Pages

Study on the Time-Varying Stiffness Characteristics of Four-Point Contact Ball Bearings

  • Runlin Chen,
  • Jiakai Li,
  • Yimo Wang,
  • Rushen Deng,
  • Weihao Chen and
  • Wenhui Li

This paper takes a four-point contact ball bearing of a wind turbine as the research object, analyzes the force and deformation relationship under the combined action of axial load and radial load, obtains the load distribution of rolling elements, a...

  • Article
  • Open Access
11 Citations
5,067 Views
17 Pages

22 February 2019

Traditional correlation analysis is analyzed separately in the time domain or the frequency domain, which cannot reflect the time-varying and frequency-varying characteristics of non-stationary signals. Therefore, a time–frequency (TF) correlat...

  • Article
  • Open Access
1 Citations
2,213 Views
26 Pages

29 March 2024

Underwater signal processing is primarily based on sound waves because of the unique properties of water. However, the slow speed and limited bandwidth of sound introduce numerous challenges, including pronounced time-varying characteristics and sign...

  • Article
  • Open Access
9 Citations
2,805 Views
28 Pages

21 February 2024

Accurate short-term load forecasting (STLF) is essential for power grid systems to ensure reliability, security and cost efficiency. Thanks to advanced smart sensor technologies, time-series data related to power load can be captured for STLF. Recent...

  • Article
  • Open Access
7 Citations
3,764 Views
15 Pages

Several studies have explored the linkage between non-performing loans and major macroeconomic indicators, using a wide variety of methodologies, sometimes with different results. This occurs, we argue, because these relationships are generally deriv...

  • Article
  • Open Access
15 Citations
5,590 Views
16 Pages

31 May 2023

More accurate traffic prediction can further improve the efficiency of intelligent transportation systems. However, the complex spatiotemporal correlation issues in transportation networks pose great challenges. In the past, people have carried out a...

  • Article
  • Open Access
10 Citations
6,618 Views
17 Pages

The nature of the relation between stock returns and the three monetary variables of interest rates (bond yields), inflation and money supply growth, while oft studied, is one that remains unclear. We argue that the nature of the relation changes ove...

  • Article
  • Open Access
9 Citations
2,532 Views
16 Pages

Theoretical Research on Diffusion Radius of Cement-Based Materials Considering the Pore Characteristics of Porous Media

  • Bao Xie,
  • Hua Cheng,
  • Xuesong Wang,
  • Zhishu Yao,
  • Chuanxin Rong,
  • Ruihe Zhou,
  • Liangliang Zhang,
  • Longhui Guo,
  • Hong Yu and
  • Xusong Xiang
  • + 1 author

3 November 2022

In engineering, loose sandy (gravelly) strata are often filled with cement-based grout to form a mixed material with a certain strength and impermeability, so as to improve the mechanical properties of sandy (gravelly) strata. The tortuosity effect o...

  • Article
  • Open Access
3 Citations
3,884 Views
16 Pages

The aim of this study is to investigate the herding of beta transmission between return and volatility. We have used the dynamic conditional correlation model with the mixed-data sampling (DCC-MIDAS) model for the analysis. The evidence demonstrates...

  • Article
  • Open Access
12 Citations
6,593 Views
23 Pages

For this paper, we dynamically analysed the comovements between three major stock markets—Germany, the UK, and the US—and the countries of the European Union, divided into two groups: Eurozone and non-Eurozone. Correlation coefficients ba...

  • Technical Note
  • Open Access
1 Citations
1,469 Views
13 Pages

28 August 2024

The conventional average acceleration approach relies on K-band range observation, containing an unknown bias, which leads to possible degradation of the precision of Earth’s gravity field modelling. It also suffers from correlated errors cause...

  • Article
  • Open Access
8 Citations
3,378 Views
13 Pages

23 September 2018

This paper focuses on the time-varying correlation among China’s seven emissions trading scheme markets. Correlation analysis shows a weak connection among these markets for the whole sample period, which spans from 9 June 2014 to 30 June 2017....

  • Article
  • Open Access
3 Citations
2,231 Views
17 Pages

Time-Varying Channel Estimation Based on Distributed Compressed Sensing for OFDM Systems

  • Yong Ding,
  • Honggao Deng,
  • Yuelei Xie,
  • Haitao Wang and
  • Shaoshuai Sun

1 June 2024

For orthogonal frequency division multiplexing (OFDM) systems in high-mobility scenarios, the estimation of time-varying multipath channels not only has a large error, which affects system performance, but also requires plenty of pilots, resulting in...

  • Article
  • Open Access
22 Citations
1,712 Views
24 Pages

This paper shows solicitude for the generalized projective synchronization of Caputo fractional-order uncertain memristive neural networks (FOUMNNs) with multiple delays. By extending the constant scale factor to the time-varying function matrix, we...

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