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Article
Publication date: 15 November 2011

Mehdi Dehghan and Masoud Hajarian

The purpose of this paper is to find the efficient iterative methods for solving the general matrix equation A1X+ XA2+A3XH+XHA4=B (including Lyapunov and Sylvester matrix

Abstract

Purpose

The purpose of this paper is to find the efficient iterative methods for solving the general matrix equation A1X+ XA2+A3XH+XHA4=B (including Lyapunov and Sylvester matrix equations as special cases) with the unknown complex (reflexive) matrix X.

Design/methodology/approach

By applying the principle of hierarchical identification and the Hermitian/skew‐Hermitian splitting of the coefficient matrix quadruplet A1; A2; A3; A4 the authors propose a shift‐splitting hierarchical identification (SSHI) method to solve the general linear matrix equation A1X+XA2+A3XH+XHA4=B. Also, the proposed algorithm is extended for finding the reflexive solution to this matrix equation.

Findings

The authors propose two iterative methods for finding the solution and reflexive solution of the general linear matrix equation, respectively. The proposed algorithms have a simple, neat and elegant structure. The convergence analysis of the methods is also discussed. Some numerical results are given which illustrate the power and effectiveness of the proposed algorithms.

Originality/value

So far, several methods have been presented and used for solving the matrix equations by using vec operator and Kronecker product, generalized inverse, generalized singular value decomposition (GSVD) and canonical correlation decomposition (CCD) of matrices. In several cases, it is difficult to find the solutions by using matrix decomposition and generalized inverse. Also vec operator and Kronecker product enlarge the size of the matrix greatly therefore the computations are very expensive in the process of finding solutions. To overcome these complications and drawbacks, by using the hierarchical identification principle and the Hermitian=skew‐Hermitian splitting of the coefficient matrix quadruplet (A1; A2; A3; A4), the authors propose SSHI methods for solving the general matrix equation.

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Article
Publication date: 3 July 2017

Masoud Hajarian

The purpose of this paper is to obtain an iterative algorithm to find the solution of the coupled Sylvester-like matrix equations.

Abstract

Purpose

The purpose of this paper is to obtain an iterative algorithm to find the solution of the coupled Sylvester-like matrix equations.

Design/methodology/approach

In this work, the matrix form of the conjugate direction (CD) algorithm to find the solution X of the coupled Sylvester-like matrix equations:

{A1XB1+M1f1(X)N1=F1,A2XB2+M2f2(X)N2=F2,
with fi(X) = X, fi(X) = X¯, fi(X) = XT and fi(X) = XH for i = 1; 2 has been established.

Findings

It is proven that the algorithm converges to the solution within a finite number of iterations in the absence of round-off errors. Finally, four numerical examples were used to test the proficiency and convergence of the established algorithm.

Originality/value

The numerical examples have led the author to believe that the generalized CD (GCD) algorithm is efficient and it converges more rapidly in comparison with the CGNR and CGNE algorithms.

Details

Engineering Computations, vol. 34 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 27 May 2014

Masoud Hajarian

The linear matrix equations have wide applications in engineering, physics, economics and statistics. The purpose of this paper is to introduce iterative methods for…

Abstract

Purpose

The linear matrix equations have wide applications in engineering, physics, economics and statistics. The purpose of this paper is to introduce iterative methods for solving the systems of linear matrix equations.

Design/methodology/approach

According to the hierarchical identification principle, the authors construct alternating direction gradient-based iterative (ADGI) methods to solve systems of linear matrix equations.

Findings

The authors propose efficient ADGI methods to solve the systems of linear matrix equations. It is proven that the ADGI methods consistently converge to the solution for any initial matrix. Moreover, the constructed methods are extended for finding the reflexive solution to the systems of linear matrix equations.

Originality/value

This paper proposes efficient iterative methods without computing any matrix inverses, vec operator and Kronecker product for finding the solution of the systems of linear matrix equations.

Details

Engineering Computations, vol. 31 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 3 September 2018

Kurnianingsih Kurnianingsih, Lukito Edi Nugroho, Widyawan Widyawan, Lutfan Lazuardi, Anton Satria Prabuwono and Teddy Mantoro

The decline of the motoric and cognitive functions of the elderly and the high risk of changes in their vital signs lead to some disabilities that inconvenience them. This…

Abstract

Purpose

The decline of the motoric and cognitive functions of the elderly and the high risk of changes in their vital signs lead to some disabilities that inconvenience them. This paper aims to assist the elderly in their daily lives through personalized and seamless technologies.

Design/methodology/approach

The authors developed a personalized adaptive system for elderly care in a smart home using a fuzzy inference system (FIS), which consists of a predictive positioning system, reflexive alert system and adaptive conditioning system. Reflexive sensing is obtained from a body sensor and environmental sensor networks. Three methods comprising the FIS generation algorithm – fuzzy subtractive clustering (FSC), grid partitioning and fuzzy c-means clustering (FCM) – were compared to obtain the best prediction accuracy.

Findings

The results of the experiment showed that FSC produced the best F1-score (96 per cent positioning accuracy, 94 per cent reflexive alert accuracy, 96 per cent air conditioning accuracy and 95 per cent lighting conditioning accuracy), whereas others failed to predict some classes and had lower validation accuracy results. Therefore, it is concluded that FSC is the best FIS generation method for our proposed system.

Social implications

Personalized and seamless technologies for elderly implies life-share awareness, stakeholder awareness and community awareness.

Originality/value

This paper presents a model of personalized adaptive system based on their preferences and medical reference, which consists of a predictive positioning system, reflexive alert system and adaptive conditioning system.

Details

International Journal of Pervasive Computing and Communications, vol. 14 no. 3/4
Type: Research Article
ISSN: 1742-7371

Keywords

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Article
Publication date: 9 January 2017

Jaime Gil Aluja

This work aims to ask for the possibility to establish one or more Europes in a heterogeneous territory where the main goal is to create a common space. The use of a…

Abstract

Purpose

This work aims to ask for the possibility to establish one or more Europes in a heterogeneous territory where the main goal is to create a common space. The use of a specific methodology will help us to know whether it is possible to apply general policies in the whole territory or it will be necessary to adapt them to a different group of spaces.

Design/methodology/approach

Taking into account the experts’ opinions, causality relationships, grouping processes and distances techniques can be obtained to get an overall view of different groups of areas where it will be possible to develop the specific policies successfully.

Findings

Theoretically, the proposed model using fuzzy logic in grouping processes presents significant results that contribute to the theory on regional development.

Originality/value

This paper provides a new approach to solve the territorial problem to apply the European policies. Introducing these techniques, one will be able to approach the different positions to the specific areas in Europe to create a peaceful and harmonic space of cohabitation.

Details

Kybernetes, vol. 46 no. 1
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 24 May 2013

Emili Vizuete Luciano, Anna Maria Gil‐Lafuente, Ana García González and Sefa Boria‐Reverter

The purpose of this study is to develop a model that illustrated how influences are interpreted and then shaped by an economy into its commitment towards corporate social…

Abstract

Purpose

The purpose of this study is to develop a model that illustrated how influences are interpreted and then shaped by an economy into its commitment towards corporate social and environmental responsibility (CSER).

Design/methodology/approach

The paper considers this question: is this possible to find some first and second effects about CSER in 24 sectors of Catalonian economy?

Findings

The analytical model is used in order to develop a conceptual model to explain the forgotten effects or CSER in Catalonia, Spain.

Originality/value

This paper applies the theory of the forgotten effects with the analysis of the causes or external elements to the Catalonian economy and of the effects or reflections that it produces in the sustainability.

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Article
Publication date: 6 May 2020

Julio Rojas-Mora, Felipe Chávez-Bustamante and Cristian Mondaca-Marino

The purpose of this paper is to evaluate Chinese indirect trade relations in the global trade network to observe if the objectives identified by Cai (2017) in the Belt and…

Abstract

Purpose

The purpose of this paper is to evaluate Chinese indirect trade relations in the global trade network to observe if the objectives identified by Cai (2017) in the Belt and Road Initiative (BRI) are being fulfilled, especially with Latin America and the Caribbean (LAC) countries.

Design/methodology/approach

Using data from the UNCTAD (2016) for the period 2011–2015, a normalized exports network is built. It is analyzed with the Forgotten Effects Theory and the PageRank algorithm. A Monte Carlo experiment with 10,000 replicates is performed to account for its volatility.

Findings

The paper identifies one instance in which China's peripheral countries are importing raw materials and commodities -–oil products – to produce low technological value-added products, which, in turn, are exported to China. LAC countries do not have significant indirect trade relations with China when the former is the origin country, while the latter is the destination in a trade relationship. The trade network has a clear core-periphery structure, with China belonging to its core, although being only the fourth most central node in the network.

Originality/value

This paper contributes with both a new methodology for the analysis of indirect trade relations and the results found for China under the BRI and its trade relationship with LAC economies.

Details

Asian Education and Development Studies, vol. 10 no. 3
Type: Research Article
ISSN: 2046-3162

Keywords

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Article
Publication date: 3 June 2014

Hung-Chun Huang and Hsin-Yu Shih

This paper aims to provide a macro perspective on diffusion structure research, and to investigate the deep structure of international technology diffusion and structural…

Abstract

Purpose

This paper aims to provide a macro perspective on diffusion structure research, and to investigate the deep structure of international technology diffusion and structural differences between technology diffusion networks. This work also provides an understanding of the nature of globalization. Globalization has highlighted changes in socioeconomics and is reshaping the world. However, when comparing endogenous factors, exogenous factors are complex and demonstrate themselves as network phenomena. These network phenomena compose themselves as neither sole nor independent units. Countries in the global network act interdependently, and heavily influence one another.

Design/methodology/approach

This study utilizes social network analysis to investigate the structural configuration of international technology diffusion. This investigation uses a sample of 42 countries over the period from 1997 to 2008. The data set contains two categories: bilateral trade flow and aggregate R&D expenditure. Meanwhile, this study uses block model analysis to reveal a network structure, which can precisely illustrate a global network configuration.

Findings

The findings not only illustrate the pattern change of diffusion from a cascade-like to radial-like structure, but also present the structural configuration of technologically advanced countries and their competitive positions.

Practical implications

In the shift to a diffusive structure, time and space are represented in new ways. Therefore, radial-like diffusion structure can provide some technological development approaches for countries interested in exogenous effects for technological growth and managing their international relation.

Originality/value

This study is the first to use a multilateral perspective and longitudinal data to examine a cross-country network structure, to provide an understanding of the nature of globalization, its conceptualization and how influence and effects are transmitted through the interconnectedness of international technology diffusion.

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Article
Publication date: 11 November 2013

William Varey

The development of capacities for sustainability thinking by large-scale social systems requires of the skilled practitioner complex abstract logics. There is an intricate…

Abstract

Purpose

The development of capacities for sustainability thinking by large-scale social systems requires of the skilled practitioner complex abstract logics. There is an intricate complexity of relationships to consider in the observation of the landscape of thought. This paper aims to introduce a matrix as an orientating heuristic to guide this form of praxis and provides reflections on its use in the enactment of social learning.

Design/methodology/approach

The signifiers for four different orientations to learning and four abstractions in levels of learning are described. The configurations that result from their conjunction generate a matrix of 16 alternatives. These are combined into a heuristic to guide and inform reflexive praxis.

Findings

The conjunction of these two dimensions enables observations of the cybernetic interactions between levels of learning and orientations to learning. This depiction prompts considerations of the ethics and aesthetics of large-scale collaborative learning. In reflecting on the use of the heuristic device in practice, four primary observations are offered as possible considerations to inform ethical practice.

Originality/value

The value of this research is in enabling awareness of the relationship between levels of learning and orientations to learning. The originality is the application of apithology principles to the multi-dimensional learning landscapes found in complex thought-ecologies.

Details

Kybernetes, vol. 42 no. 9/10
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 13 July 2012

Mehdi Dehghan and Masoud Hajarian

The purpose of this paper is to find two iterative methods to solve the general coupled matrix equations over the generalized centro‐symmetric and central antisymmetric matrices.

Abstract

Purpose

The purpose of this paper is to find two iterative methods to solve the general coupled matrix equations over the generalized centro‐symmetric and central antisymmetric matrices.

Design/methodology/approach

By extending the idea of conjugate gradient (CG) method, the authors present two iterative methods to solve the general coupled matrix equations over the generalized centro‐symmetric and central antisymmetric matrices.

Findings

When the general coupled matrix equations are consistent over the generalized centro‐symmetric and central anti‐symmetric matrices, the generalized centro‐symmetric and central anti‐symmetric solutions can be obtained within nite iterative steps. Also the least Frobenius norm generalized centrosymmetric and central anti‐symmetric solutions can be derived by choosing a special kind of initial matrices. Furthermore, the optimal approximation generalized centrosymmetric and central anti‐symmetric solutions to given generalized centro‐symmetric and central anti‐symmetric matrices can be obtained by finding the least Frobenius norm generalized centro‐symmetric and central anti‐symmetric solutions of new matrix equations. The authors employ some numerical examples to support the theoretical results of this paper. Finally, the application of the presented methods is highlighted for solving the projected generalized continuous‐time algebraic Lyapunov equations (GCALE).

Originality/value

By the algorithms, the solvability of the general coupled matrix equations over generalized centro‐symmetric and central anti‐symmetric matrices can be determined automatically. The convergence results of the iterative algorithms are also proposed. Several examples and an application are given to show the efficiency of the presented methods.

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