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Article
Publication date: 18 December 2023

Xiaojie Xu and Yun Zhang

This study aims to investigate dynamic relations among office property price indices of 10 major cities in China for the years 2005–2021.

Abstract

Purpose

This study aims to investigate dynamic relations among office property price indices of 10 major cities in China for the years 2005–2021.

Design/methodology/approach

Using monthly data, the authors adopt vector error correction modeling and the directed acyclic graph for the characterization of contemporaneous causality among the 10 indices.

Findings

The PC algorithm identifies the causal pattern, and the linear non-Gaussian acyclic model algorithm further determines the causal path from which we perform innovation accounting analysis. Sophisticated price dynamics are found in price adjustment processes following price shocks, which are generally dominated by the top tier of cities.

Originality/value

This suggests that policies on office property prices, in the long run, might need to be planned with particular attention paid to the top tier of cities.

Article
Publication date: 17 April 2024

Cheng Xiong, Bo Xu and Zhenqian Chen

This study aims to investigate the rarefaction effects on flow and thermal performances of an equivalent sand-grain roughness model for aerodynamic thrust bearing.

Abstract

Purpose

This study aims to investigate the rarefaction effects on flow and thermal performances of an equivalent sand-grain roughness model for aerodynamic thrust bearing.

Design/methodology/approach

In this study, a model of gas lubrication thrust bearing was established by modifying the wall roughness and considering rarefaction effect. The flow and lubrication characteristics of gas film were discussed based on the equivalent sand roughness model and rarefaction effect.

Findings

The boundary slip and the surface roughness effect lead to a decrease in gas film pressure and temperature, with a maximum decrease of 39.2% and 8.4%, respectively. The vortex effect present in the gas film is closely linked to the gas film’s pressure. Slip flow decreases the vortex effect, and an increase in roughness results in the development of slip flow. The increase of roughness leads to a decrease for the static and thermal characteristics.

Originality/value

This work uses the rarefaction effect and the equivalent sand roughness model to investigate the lubrication characteristics of gas thrust bearing. The results help to guide the selection of the surface roughness of rotor and bearing, so as to fully control the rarefaction effect and make use of it.

Details

Industrial Lubrication and Tribology, vol. 76 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 13 October 2022

Pablo Durán Santomil, Pablo Crisanto Lombardero Fernández and Luis Otero González

The purpose of this study is to evaluate whether the classification of the equity mutual fund depends on the performance measure used.

Abstract

Purpose

The purpose of this study is to evaluate whether the classification of the equity mutual fund depends on the performance measure used.

Design/methodology/approach

The sample for this study includes stock mutual funds for the USA, Europe and emerging market economies covering the period 2010 to 2020. Using more than 20 performance measures the results are compared using the Sharpe ratio as the reference.

Findings

The results show that performance measures based on absolute reward–risk ratios like Sortino, Treynor, etc. have similar rankings, because in general the numerator (mean excess return) is the same. However, when the authors employ other types of performance measures, results may be significantly different, especially in the case of metrics for “incremental returns”, i.e. alphas. Focussing on markets, their results show that choosing performance measures is more relevant for emerging markets.

Research limitations/implications

The sample is only limited to the USA, Europe and the emerging market, and there are other performance metrics in the literature which have not been covered in this work.

Practical implications

The ordering of equity mutual funds depends on the measure used, specially if investors employ factor models to measure excess returns (alphas). Hence, policy formulation on disclosure of mutual fund performance should encourage the use of several metrics from different families. Investors must be aware of the different rankings made and the most appropriate metrics based on their preferences.

Originality/value

This paper focusses specifically on the effect that performance metrics have on relative fund performance. Previous studies have ignored alpha metrics to rank funds, which are commonly employed by investors. The authors’ study performs an analysis for three different markets considering the two main developed ones (the American and European equity markets), as well as the emerging one, largely ignored until now.

Details

International Journal of Emerging Markets, vol. 19 no. 7
Type: Research Article
ISSN: 1746-8809

Keywords

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