KEVIN AMARATUNGA and JOHN R. WILLIAMS
We describe how wavelets may be used to solve partial differential equations. These problems are currently solved by techniques such as finite differences, finite elements and…
Abstract
We describe how wavelets may be used to solve partial differential equations. These problems are currently solved by techniques such as finite differences, finite elements and multigrid. The wavelet method, however, offers several advantages over traditional methods. Wavelets have the ability to represent functions at different levels of resolution, thereby providing a logical means of developing a hierarchy of solutions. Furthermore, compactly supported wavelets (such as those due to Daubechies) are localized in space, which means that the solution can be refined in regions of high gradient, e.g. stress concentrations, without having to regenerate the mesh for the entire problem. To demonstrate the wavelet technique, we consider Poisson's equation in two dimensions. By comparison with a simple finite difference solution to this problem with periodic boundary conditions we show how a wavelet technique may be efficiently developed. Dirichlet boundary conditions are then imposed, using the capacitance matrix method described by Proskurowski and Widlund and others. The convergence of the wavelet solutions are examined and they are found to compare extremely favourably to the finite difference solutions. Preliminary investigations also indicate that the wavelet technique is a strong contender to the finite element method.
Details
Keywords
S. D'Heedene, K. Amaratunga and J. Castrillón‐Candás
This paper presents a novel framework for solving elliptic partial differential equations (PDEs) over irregularly spaced meshes on bounded domains.
Abstract
Purpose
This paper presents a novel framework for solving elliptic partial differential equations (PDEs) over irregularly spaced meshes on bounded domains.
Design/methodology/approach
Second‐generation wavelet construction gives rise to a powerful generalization of the traditional hierarchical basis (HB) finite element method (FEM). A framework based on piecewise polynomial Lagrangian multiwavelets is used to generate customized multiresolution bases that have not only HB properties but also additional qualities.
Findings
For the 1D Poisson problem, we propose – for any given order of approximation – a compact closed‐form wavelet basis that block‐diagonalizes the stiffness matrix. With this wavelet choice, all coupling between the coarse scale and detail scales in the matrix is eliminated. In contrast, traditional higher‐order (n>1) HB do not exhibit this property. We also achieve full scale‐decoupling for the 2D Poisson problem on an irregular mesh. No traditional HB has this quality in 2D.
Research limitations/implications
Similar techniques may be applied to scale‐decouple the multiresolution finite element (FE) matrices associated with more general elliptic PDEs.
Practical implications
By decoupling scales in the FE matrix, the wavelet formulation lends itself particularly well to adaptive refinement schemes.
Originality/value
The paper explains second‐generation wavelet construction in a Lagrangian FE context. For 1D higher‐order and 2D first‐order bases, we propose a particular choice of wavelet, customized to the Poisson problem. The approach generalizes to other elliptic PDE problems.
Details
Keywords
Richard Haigh and Dilanthi Amaratunga
The purpose of this paper is to present an integrative review of the literature to explore the nature of the built environment discipline's potential role in the development of…
Abstract
Purpose
The purpose of this paper is to present an integrative review of the literature to explore the nature of the built environment discipline's potential role in the development of society's resilience to disasters.
Design/methodology/approach
The integrative literature review method is used to address this emerging topic and present a holistic conceptualisation of the literature. For the purpose of this review, the Business Source Premier (EBSCO), Emerald Management eJournals, Management & Organization Studies (CSA) and Science Direct (Elsevier) electronic databases are the main source for identifying studies, along with conference proceedings from the events of major built environment and disaster‐related networks.
Findings
A review of the literature reveals that the built environment “discipline”, at each stage of the disaster management process, has invaluable expertise and a key role to play in the development of society's resilience to disasters. However, the collaborative definition of the built environment hides many of its underlying properties, which are multi‐disciplinary in nature. It is important that a suitable conceptual framework is developed that explores the interaction between the built environment, its disciplines, and the disaster management process.
Originality/value
At present, research on disasters and the built environment is sporadic, hindered by an ill‐defined disciplinary base. When searching for emergent theory, a conceptual framework is important for situating further study in the relevant knowledge bases that lay the foundation for the development of a theoretical base for the field.
Details
Keywords
Kumar Kaushik Ranjan, Sandeep Kumar, Amit Tyagi and Ambuj Sharma
The real challenge in the solution of contact problems is the lack of an optimal adaptive scheme. As the contact zone is a priori unknown, successive refinement and iterative…
Abstract
Purpose
The real challenge in the solution of contact problems is the lack of an optimal adaptive scheme. As the contact zone is a priori unknown, successive refinement and iterative method are necessary to obtain a high-accuracy solution. The purpose of this paper is to provide an optimal adaptive scheme based on second-generation finite element wavelets for the solution of non-linear variational inequality of the contact problem.
Design/methodology/approach
To generate an elementary multi-resolution mesh, the authors used hierarchical bases (HB) composed of Lagrange finite element interpolation functions. These HB functions are customized using second-generation wavelet techniques for a fast convergence rate. At each step of the algorithm, the active set method along with mesh adaptation is used for solving the constrained minimization problem of contact case. Wavelet coefficients-based error indicators are used, and computation is focused on mesh zones with a high error indication. The authors take advantage of the wavelet transform to develop a parameter-free adaptive scheme to generate an appropriate and optimal mesh.
Findings
Adaptive wavelet Galerkin scheme (AWGS), a newly developed method for multi-scale mesh adaptivity in this work, is a combination of the second-generation wavelet transform and finite element method and significantly improves the accuracy of the results without approximating an additional problem of error estimation equations. A comparative study is performed taking a solution on a highly refined mesh and results are generated using AWGS.
Practical implications
The proposed adaptive technique can be utilized in the simulation of mechanical and biomechanical structures where multiple bodies come into contact with each other. The algorithm of the method is easy to implement and found to be successful in producing a sufficiently accurate solution with relatively less number of mesh nodes.
Originality/value
Although many error estimation techniques have been developed over the past several years to solve contact problems adaptively, because of boundary non-linearity development, a reliable error estimator needs further investigation. The present study attempts to resolve this problem without having to recompute the entire solution on a new mesh.
Details
Keywords
Dilanthi Amaratunga, Chamindi Ishara Malalgoda and Kaushal Keraminiyage
Construction industry and the built environment professions play an important role in contributing to society’s improved resilience. It is therefore important to improve their…
Abstract
Purpose
Construction industry and the built environment professions play an important role in contributing to society’s improved resilience. It is therefore important to improve their knowledgebase to strengthen their capacities. This paper aims to identify gaps in the knowledgebase of construction professionals that are undermining their ability to contribute to the development of a more disaster resilient society. The paper also provides a series of recommendations to key actors in the built environment on how to more effectively mainstream disaster resilience in the construction process.
Design/methodology/approach
The paper reports the findings of 87 stakeholder interviews with: national and local government organisations; the community; non-governmental organisations, international non-governmental organisation and other international agencies; academia and research organisations; and the private sector, which were supplemented by a comprehensive analysis of key policies related to disaster resilience and management. The findings were validated using focus group discussions that were conducted as part of six organised stakeholder workshops.
Findings
The primary and secondary data generated a long list of needs and skills. Finally, the identified needs and skills were combined “like-for-like” to produce broader knowledge gaps. Some of the key knowledge gaps identified are: governance, legal frameworks and compliance; business continuity management; disaster response; contracts and procurement; resilience technologies, engineering and infrastructure; knowledge management; social and cultural awareness; sustainability and resilience; ethics and human rights; innovative financing mechanisms; multi stakeholder approach, inclusion and empowerment; post disaster project management; and multi hazard risk assessment. The study also identifies a series of recommendations to key actors in the built environment on how to more effectively mainstream disaster resilience in the construction process. The recommendations are set out in five key themes: education, policy, practice, research and cross-cutting.
Research limitations/implications
This study is part of an EU funded research project that is seeking to develop innovative and timely professional education that will update the knowledge and skills of construction professionals in the industry and enable them to contribute more effectively to disaster resilience building efforts.
Originality/value
The paper provides an extensive analysis of the gaps in the knowledgebase of construction professionals that are undermining their ability to contribute to the development of a more disaster resilient society. Accordingly, the paper recommends major changes in construction education, research, policy and practice with respect to mainstreaming disaster resilience within the construction process.
Details
Keywords
Taufika Ophiyandri, Dilanthi Amaratunga and Kaushal Keraminiyage
The purpose of this paper is to discuss the advantages and limitations of the implementation of a community-based method in post-disaster housing reconstruction.
Abstract
Purpose
The purpose of this paper is to discuss the advantages and limitations of the implementation of a community-based method in post-disaster housing reconstruction.
Design/methodology/approach
The research was based on multiple case studies in the implementation of a community-based post-disaster housing reconstruction project (CPHRP) in Indonesia. Data were gathered by conducting semi-structured interviews and a questionnaire survey.
Findings
The research reveals 22 advantages of a CPHRP. Four advantages can be categorised as highly significant. They are create sense of ownership, fit to local culture/customs/wisdom, build beneficiaries’ confidence and minimize corruption. There are some advantages that cannot be delivered if the housing reconstruction is conducted using a contractor-based approach. It was also found that psychological advantages are more dominant than the physical advantages. Despite its numerous advantages, CPHRP has limitations. First, it requires a long pre-construction process and, second, there is a limitation with regard to the capacity of implementer and there are limitations within the community itself.
Originality/value
This paper is very specific because it attempts to discover the advantages and limitations of a CPHRP.
Details
Keywords
Kristen MacAskill and Peter Guthrie
This paper examines the role of government in New Zealand in facilitating the development of resilience in the built environment, with reference to the post-earthquake recovery of…
Abstract
Purpose
This paper examines the role of government in New Zealand in facilitating the development of resilience in the built environment, with reference to the post-earthquake recovery of Christchurch. A cross-case comparison of the institutional structures and arrangements for disaster risk management (DRM) between Sri Lanka and New Zealand provides a useful basis to consider the broader implications of the findings from both countries. Particular consideration is given to the role of community participation in DRM decisions.
Design/methodology/approach
Malalgoda and Amaratunga (2015) recently published an article on empowering local governments to develop resilience in the built environment in Sri Lanka. This paper provides a response to their discussion in conjunction with a New Zealand case study.
Findings
Despite being one of the most advanced countries in the world with regards to DRM, New Zealand faces significant challenges in implementation, chief amongst which is that local governments have yet to truly prioritize DRM in urban development. While community consultation is embedded in the legislative framework, requirements for consultation were somewhat misjudged by the local government in Christchurch’s recovery. A lesson to be learnt from Christchurch’s experience is that even if the Sri Lankan authorities follow Malalgoda and Amaratunga’s recommendations for greater devolution of powers to local government, there will be tensions if community expectations over consultation are not met.
Originality/value
The cross-case analysis offers a helpful lens through which it is possible to examine DRM. It is useful for informing governments and other stakeholders, helping them to understand the challenges their institutions may face in facilitating DRM and building resilience.
Details
Keywords
Tri Yumarni and Dilanthi Amaratunga
The purpose of this paper is to discuss policy-relevant findings regarding strategies for mainstreaming gender in achieving sustainable post-disaster reconstruction (PDR).
Abstract
Purpose
The purpose of this paper is to discuss policy-relevant findings regarding strategies for mainstreaming gender in achieving sustainable post-disaster reconstruction (PDR).
Design/methodology/approach
An exploratory case study was used to explore the implementation of gender mainstreaming strategies and the link to sustainable PDR. The Bantul and Sleman regencies of Yogyakarta province provide a unique site for researching PDR as they are located in a region that is more strongly affected by earthquakes than nearly any other in Indonesia. Data were collected through interviews with 17 key stakeholders and 26 beneficiaries who were involved during and after the earthquake. To support the interview findings, surveys involving 50 policy makers and 150 beneficiaries were conducted. Content analysis and t-statistics were used in analyzing the data.
Findings
Gender mainstreaming strategies within sustainable reconstruction should incorporate strategies for protecting against gender vulnerabilities and for promoting gender capacities. Both are fundamental to the achievement of sustainable PDR.
Originality/value
The paper establishes comprehensive strategies for mainstreaming gender under three pillars (i.e. economic, social and environmental) of sustainable development. The findings benefit relevant policy makers by improving the policy performance of gender mainstreaming in the affected communities in enhancing sustainable PDR.
Details
Keywords
Taufika Ophiyandri, Dilanthi Amaratunga, Chaminda Pathirage and Kaushal Keraminiyage
The purpose of this paper is to investigate the critical success factors (CSFs) of community‐based post‐disaster housing reconstruction projects (CPHRP) during the…
Abstract
Purpose
The purpose of this paper is to investigate the critical success factors (CSFs) of community‐based post‐disaster housing reconstruction projects (CPHRP) during the pre‐construction stage.
Design/methodology/approach
An extensive literature review and interviews were undertaken to establish selected factors contributing to the success of community‐based post disaster housing reconstruction projects. Following this, a questionnaire survey was administered to key stakeholders in order to perceive their view on CSFs of CPHRP. Data were analysed by deploying statistical software.
Findings
It was found that 12 factors are considered to be the CSFs: transparency and accountability, appropriate reconstruction policy/strategy, an understanding of the community‐based method, gathering trust from the community, facilitator capacity, good coordination and communication, sufficient funding availability, implementer capacity, having a significant level of community participation/control, government support, involvement of all community members, and successful beneficiary identification.
Practical implications
The establishment of CSFs in CPHRP helps key stakeholders to identify factors that must exist and go well during pre‐construction of CPHRP, in order to ensure the success of the programme.
Originality/value
The paper is very specific as it attempts to discover the CSFs of CPHRP during the pre‐construction stage.
Details
Keywords
Gayani Karunasena and Dilanthi Amaratunga
The purpose of this paper is to focus on the identification of the existing capacities of post disaster C & D waste management in developing countries, with a special…
Abstract
Purpose
The purpose of this paper is to focus on the identification of the existing capacities of post disaster C & D waste management in developing countries, with a special emphasis on Sri Lanka to determine the capacity gaps and related influencing factors.
Design/methodology/approach
Multiple case studies and expert interviews were conducted to gather primary information on the existing capacities of disaster C & D waste management. Three case studies, including 15 individuals and six experts representing government, non-government institutions and others, were selected.
Findings
The results revealed the existing capacities, capacity gaps and influencing factors for post disaster C & D waste management in the areas of skills and confidence building, links and collaborations, continuity and sustainability, research and development, communication and coordination, organisational implementation and investment in infrastructure.
Research limitations/implications
This study limited disaster C & D waste to debris generated from totally or partially damaged buildings and infrastructure as a direct impact of natural disasters or from demolished buildings and infrastructure at rehabilitation or at early recovery stages.
Originality/value
The research enabled an analysis of existing capacities and identified capacity gaps in post disaster C & D waste management with influencing factors developing countries.