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Book part
Publication date: 18 January 2022

Arnab Bhattacharjee, Jan Ditzen and Sean Holly

The authors provide a way to represent spatial and temporal equilibria in terms of error correction models in a panel setting. This requires potentially two different processes…

Abstract

The authors provide a way to represent spatial and temporal equilibria in terms of error correction models in a panel setting. This requires potentially two different processes for spatial or network dynamics, both of which can be expressed in terms of spatial weights matrices. The first captures strong cross-sectional dependence, so that a spatial difference, suitably defined, is weakly cross-section dependent (granular) but can be non-stationary. The second is a conventional weights matrix that captures short-run spatio-temporal dynamics as stationary and granular processes. In large samples, cross-section averages serve the first purpose and the authors propose the mean group, common correlated effects estimator together with multiple testing of cross-correlations to provide the short-run spatial weights. The authors apply this model to the 324 local authorities of England, and show that our approach is useful for modeling weak and strong cross-section dependence, together with partial adjustments to two long-run equilibrium relationships and short-run spatio-temporal dynamics. This exercise provides new insights on the (spatial) long-run relationship between house prices and income in the UK.

Details

Essays in Honor of M. Hashem Pesaran: Panel Modeling, Micro Applications, and Econometric Methodology
Type: Book
ISBN: 978-1-80262-065-8

Keywords

Article
Publication date: 28 June 2021

Flávio Arrais, Nuno Lopes and Paulo Vila Real

Sigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible…

Abstract

Purpose

Sigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible to local, distortional and lateral-torsional buckling, as possible failure modes when compared to common I-sections and hollow cross-sections. However, the instability phenomena associated to these members are not completely understood in fire situation. Therefore, the purpose of this study is to analyse the behaviour of beams composed of cold-formed sigma sections at elevated temperatures.

Design/methodology/approach

This study presents a numerical analysis, using advanced methods by applying the finite element software SAFIR. A numerical analysis of the behaviour of simply supported cold-formed sigma beams in the case of fire is presented considering different cross-section slenderness values, elevated temperatures, steel grades and bending moment diagrams. Comparisons are made between the obtained numerically ultimate bending capacities and the design bending resistances from Eurocode 3 Part 1–2 rules and its respective French National Annex (FN Annex).

Findings

The current design expressions revealed to be over conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the general prescriptions, the first having a better agreement with the numerical results.

Originality/value

Following the previous comparisons, new fire design formulae are analysed. This new methodology, which introduces minimum changes in the existing formulae, provides at the same time safety and accuracy when compared to the numerical results, considering the occurrence of local, distortional and lateral-torsional buckling phenomena in these members at elevated temperatures.

Details

Journal of Structural Fire Engineering, vol. 12 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 11 July 2016

Shuyun Ren and Tsan-Ming Choi

Panel data-based demand forecasting models have been widely adopted in various industrial settings over the past few decades. Despite being a highly versatile and intuitive…

Abstract

Purpose

Panel data-based demand forecasting models have been widely adopted in various industrial settings over the past few decades. Despite being a highly versatile and intuitive method, in the literature, there is a lack of comprehensive review examining the strengths, the weaknesses, and the industrial applications of panel data-based demand forecasting models. The purpose of this paper is to fill this gap by reviewing and exploring the features of various main stream panel data-based demand forecasting models. A novel process, in the form of a flowchart, which helps practitioners to select the right panel data models for real world industrial applications, is developed. Future research directions are proposed and discussed.

Design/methodology/approach

It is a review paper. A systematically searched and carefully selected number of panel data-based forecasting models are examined analytically. Their features are also explored and revealed.

Findings

This paper is the first one which reviews the analytical panel data models specifically for demand forecasting applications. A novel model selection process is developed to assist decision makers to select the right panel data models for their specific demand forecasting tasks. The strengths, weaknesses, and industrial applications of different panel data-based demand forecasting models are found. Future research agenda is proposed.

Research limitations/implications

This review covers most commonly used and important panel data-based models for demand forecasting. However, some hybrid models, which combine the panel data-based models with other models, are not covered.

Practical implications

The reviewed panel data-based demand forecasting models are applicable in the real world. The proposed model selection flowchart is implementable in practice and it helps practitioners to select the right panel data-based models for the respective industrial applications.

Originality/value

This paper is the first one which reviews the analytical panel data models specifically for demand forecasting applications. It is original.

Details

Industrial Management & Data Systems, vol. 116 no. 6
Type: Research Article
ISSN: 0263-5577

Keywords

Article
Publication date: 9 June 2022

Thong Duc Hong, Quan Thien Phan Nghiem, Binh Trong Nguyen and Tinh Van Mai

The purpose of this paper is to investigate the effect of different guide fins structures (i.e. single-layer and double-layer guide fins) on the exhaust flow and thermal…

Abstract

Purpose

The purpose of this paper is to investigate the effect of different guide fins structures (i.e. single-layer and double-layer guide fins) on the exhaust flow and thermal uniformity of the motorcycle exhaust thermoelectric generator.

Design/methodology/approach

One single-layer guide fins structure and three double-layer guide fins structures are numerically investigated in terms of exhaust flow uniformity with different exhaust properties. Then, the double-layer guide fins structure achieving the highest flow uniformity is fabricated and experimentally investigated on a motorcycle at different engine speeds together with the single-layer guide fins structure to evaluate the thermal uniformity.

Findings

The double-layer guide fins structure obtains a better flow uniformity and thermal uniformity compared to the single-layer structure. Among surveyed structures, the double-layer structure with three closed V-shape guide fins achieves the highest flow uniformity. This structure also improves the thermal uniformity from 3.0 to 90.1% in comparison with the single-layer structure in experiments.

Originality/value

In this paper, the double-layer guide fins structures are derived from the improvement of the single-layer guide fins structure. The fluid flow uniformity index is applied as a measure for assessing the exhaust flow uniformity. The enhancement of thermal uniformity of the double-layer guide fins structure is expected to increase the longevity and performance of the motorcycle exhaust thermoelectric generator.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 31 August 2020

Rui Dan and Zhen Shi

Objective appraisal of pressure comfort is the key point of optimal designing of clothing. The purpose of this paper is to study a new method to provide pressure comfort for the…

Abstract

Purpose

Objective appraisal of pressure comfort is the key point of optimal designing of clothing. The purpose of this paper is to study a new method to provide pressure comfort for the waist of elastic pantyhose through the relationship between pressure and displacement using the finite element method (FEM).

Design/methodology/approach

This paper presented a simulation model of the waist cross section consisting of three parts, namely skin, soft tissue and lumbar vertebrae, respectively, according to CT scan. The finite element the model of waist cross-section was established using Mimics software. The pressure–displacement quadratic equation can be obtained using ANSYS software and fitting curves. Meanwhile, we divide the waist cross-section into 12 equal regions according to angle, and then the area shrinkage mass of the waist cross-section can be calculated, respectively.

Findings

In this research work, we got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of 12 regions, and this displacement could be used as an objective evaluation index for pressure comfort. All these solutions supply a theoretical reference for optimal design of the women's elastic pantyhose.

Originality/value

The paper analyzed the relationship between pressure and displacement for the waist of elastic pantyhose using FEM, and then got the displacement distribution trend of elastic pantyhose at the waist cross section according to the area shrinkage mass of different regions. It can supply a new method to appraise pressure comfort.

Details

International Journal of Clothing Science and Technology, vol. 33 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 21 October 2019

Rui Dan and Zhen Shi

The area shrinkage of the body under pressure is very important to evaluate the comfort of pressure sense, and it is an important index that appraises compression garment. The…

Abstract

Purpose

The area shrinkage of the body under pressure is very important to evaluate the comfort of pressure sense, and it is an important index that appraises compression garment. The purpose of this paper is to obtain the area shrinkage mass of the waist cross section by using the finite-element method (FEM), and the waist of women’s pantyhose could be designed with a different degree of elasticity during the course of design based on clothing pressure comfort.

Design/methodology/approach

This study aimed at the problems existing in the wearing of women’s elastic pantyhose, took the waist of pantyhose as the research object, and the contact between human body and pantyhose as elastic contact. The finite-element model of the waist cross section and elastic pantyhose fabric was acquired through CT scan and Mimics software. After simulating on the corresponding displacement distribution of the waist of sample elastic pantyhose during the process of dressing by using ANSYS, the authors divided the waist cross section into 24 equal regions according to angle (every 15 degrees as a region), and then the area shrinkage mass of each region was obtained by area calculation formula. According to the tendency of area shrinkage distribution, the waist of women’s elastic pantyhose could be designed for different regions of tension considering the pressure comfort, so as to guarantee that the wearing comfort can be maintained on the premise of ensuring the functionality of the elastic pantyhose.

Findings

In this paper, the authors obtained the area shrinkage mass of elastic pantyhose at waist cross section, and this area shrinkage distribution could be used as an objective evaluation index for pressure comfort. All these solutions are of great significance to the optimization design of pantyhose and can provide theoretical basis for the structural improvement of functional pantyhose and the prediction of clothing pressure.

Originality/value

This paper simulated the area shrinkage mass for the waist of elastic pantyhose by using FEM, and the waist of women’s elastic pantyhose could be designed for different regions of tension considering the pressure comfort according to the area shrinkage distribution tendency, so as to guarantee the wearing comfort during the wearing process.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 7 August 2023

Rui Dan, Yujie Zheng, ZhiQin Liu and Zhen Shi

The inward displacement perpendicular to the body surface produced by compression garment is an important index to evaluate pressure comfort and optimal design of tight clothing…

Abstract

Purpose

The inward displacement perpendicular to the body surface produced by compression garment is an important index to evaluate pressure comfort and optimal design of tight clothing products. The purpose of this study is to explore the pressure distribution state at waist position of elastic legwear and then to solve the common problem of excessive pressure or easy slippage for waist of elastic legwear.

Design/methodology/approach

In this paper, the authors obtained the waist cross-section model of human body using CT scanning and mimics modeling and then simulated the pressure and displacement distribution after wearing sample four elastic legwear using finite element method. The dressing process of elastic legwear was divided into six periods (instantaneous, 1, 2, 4, 8 and 12 h) in this study, and the finite element software ANSYS was used to simulate the displacement and deformation of the waist cross section. The authors finally obtained the functional relationship between pressure/displacement ratio and angle using curve fitting.

Findings

In this paper, the authors obtained the functional relationship between pressure/displacement ratio and angle using curve fitting. Comparison found that the “pressure/displacement–angle” function curve showed an almost consistent trend at any time. That was to say, when the human body was in the state of clothing pressure, the corresponding displacement value of the human body can be calculated by the curve equation under the premise of known pressure value.

Originality/value

This study solves the difficult problem which hard to measure displacement values by conventional methods due to the small deformation of the human body after dressing the compression garment. Conclusions also provide a theoretical reference for evaluating pressure comfort and optimizing clothing structure for the elastic legwear, and this method is also applicable to other types of compression garment.

Details

International Journal of Clothing Science and Technology, vol. 35 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 5 May 2015

Da-Wei Zhang and He Yang

The purpose of this paper is to explore the basic loading state in local loading forming process of large-sized complicated rib-web component, which is important for understanding…

Abstract

Purpose

The purpose of this paper is to explore the basic loading state in local loading forming process of large-sized complicated rib-web component, which is important for understanding process characteristic, controlling metal flow and designing preformed geometry of the local loading forming process. Moreover the analytical models for different loading states are established to quickly predict the metal flow.

Design/methodology/approach

Through analysis of geometric characteristic of large-sized complicated rib-web component and the deformation characteristic on planes of metal flow by local loading method, a representative cross-section is put forward and designed, which could reflect the local loading forming characteristics of large-sized complicated rib-web component. Finite element method (FEM) is used to analyze the stress and metal flow, and the analytical models of metal flow are established by using slab method (SM).

Findings

Three local loading states and one whole loading state are found in the local loading forming process of representative cross-section. Further, four loading states also exist in local loading forming process of large-sized complicated rib-web components. With the metal distribution in the process, some local loading states may turn into whole loading state. For the representative cross-section, the relative error of metal distribution between SM and FEM results is less than 15 per cent, and the relative error of metal in the rib cavity between SM and FEM results is less than 10 per cent.

Originality/value

Metal flow can be controlled by adjusting the loading states in the process. According to the metal flow laws in different loading states, a simple unequal-thickness billet can be designed to achieve initial metal distribution, and then, the secondary metal distribution can be achieved in the process.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 17 May 2013

Akhmad Affandi and Dewi Puji Astuti

The purpose of this paper is to examine the poverty rates of Indonesia, Malaysia and Pakistan, representing majority Muslim populations, and of India as a minority Muslim…

1420

Abstract

Purpose

The purpose of this paper is to examine the poverty rates of Indonesia, Malaysia and Pakistan, representing majority Muslim populations, and of India as a minority Muslim population, according to Ibn Khaldun's dynamic model on poverty.

Design/methodology/approach

According to Ibn Khaldun, poverty is not merely influenced by economic dimension. He initiated fundamental factors as mentioned in his formula P=f(W,G,N,S,g,J ) where P is a function of Wealth of the Nation (W ), Government (G ), Human Resource (N ), Sharia (S ), Growth ( g) and Justice ( J ). This study generates secondary data covering from 2000‐2010 or after financial crisis of 1997. These data employed using Panel method.

Findings

The study's findings reveal that the variable of Dynamic model of Ibn Khaldun influenced significantly the level of poverty in Indonesia as a Muslim majority population, whereas in Pakistan only the HDI variable has significant influence. Meanwhile (like Malaysia) in India, the variable of Dynamic model of Ibn Khaldun does not influence significantly.

Research limitations/implications

Each country has certain characteristics and background with respect to economic growth, government policy and population that might influence poverty. As a result, the application of Ibn Khaldun model varies accordingly.

Practical implications

The findings reveal that quite a few challenges lie ahead in applying Ibn Khaldun model in these countries. This needs to be taken on promptly by each country, especially Muslim countries.

Originality/value

This paper is one of few studies which employ Ibn Khaldun theory on poverty, using panel data to investigate the appropriateness of the model.

Article
Publication date: 6 May 2014

Akhmad Affandi and Dewi Puji Astuti

The purpose of this study is to examine the poverty rate of Indonesia, Malaysia and Pakistan representing majority Muslim populations and that of India as a minority Muslim…

Abstract

Purpose

The purpose of this study is to examine the poverty rate of Indonesia, Malaysia and Pakistan representing majority Muslim populations and that of India as a minority Muslim population according to Ibn Khaldun's dynamic model on poverty.

Design/methodology/approach

According to Ibn Khaldun, poverty is not merely influenced by economic dimensions. He initiated fundamental factors, as mentioned in his formula, which are the functions of Wealth of the Nation, Government, Human Resource, Shariah, Growth and Justice. This study generates secondary data covering the period from 2000 to 2010 or after the financial crisis of 1997. These data were generated using the Panel method.

Findings

The findings of this study reveal that the dynamic model of Ibn Khaldun significantly influenced the level of poverty in Indonesia as a Muslim-majority population, whereas in Pakistan, only the human development index variable has a significant influence. Meanwhile, like Malaysia, in India, the dynamic model of Ibn Khaldun did not have significant influence.

Research limitations/implications

Each country has certain characteristics and background with respect to economic growth, government policy and population that might influence poverty. As a result, the application of Ibn Khaldun's model varies accordingly.

Practical implications

The findings reveal that quite a few challenges lie ahead in applying Ibn Khaldun's model in these countries. This needs to be taken on promptly by each country, especially Muslim countries.

Originality/Value

This paper is one of the few studies which use Ibn Khaldun' theory on poverty using panel data to investigate the appropriateness of the model.

Details

Humanomics, vol. 30 no. 2
Type: Research Article
ISSN: 0828-8666

Keywords

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