265 research outputs found

    Conversions between barycentric, RKFUN, and Newton representations of rational interpolants

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    We derive explicit formulas for converting between rational interpolants in barycentric, rational Krylov (RKFUN), and Newton form. We show applications of these conversions when working with rational approximants produced by the AAA algorithm [Y. Nakatsukasa, O. S\`ete, L. N. Trefethen, arXiv preprint 1612.00337, 2016] within the Rational Krylov Toolbox and for the solution of nonlinear eigenvalue problems

    Maintenance performance evaluation of offsite and in situ bathrooms

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    Purpose ā€“ Offsite is one of the main innovative techniques employed in the contemporary UK construction sector. Building maintenance accounts for over 5 percent of the UK's gross domestic product of which bathrooms are regarded as a critical area, with potential high risks and defects. However, the importance of its maintenance has been largely underestimated and research into this area appears to be limited. This paper aims to address this knowledge gap by investigating the maintenance performance of offsite and in situ bathrooms for student accommodation. Design/methodology/approach ā€“ The paper examines 732 maintenance records over three years of 216 precast concrete modules, 84 Glass Reinforced Polyester (GRP) modules and 96 traditionally-built in situ bathrooms. Findings ā€“ The research found that offsite modules outperformed in situ bathrooms in terms of maintenance. GRP modules created the least maintenance problems, compared to precast modules and in situ bathrooms. The maintenance of in situ bathrooms was more complex than offsite modules, and involved more diverse problematic areas. The main causes of the problems included inappropriate design; poor build workmanship, lack of quality of component materials and improper usage by occupants. This supports a parallel study that found that the costs associated with maintenance were significantly higher for in situ bathrooms than for the equivalent offsite solutions. Research limitations/implications ā€“ The paper contributes to understanding the problems of offsite bathroom modules requiring maintenance in comparison with in situ bathrooms and their possible causes. Key aspects of offsite bathrooms including drainage, toilets, vents and sinks should be improved. Quality of component materials used for in situ bathrooms should be ensured. These improvements can only be achieved through better design for maintenance with clients' aspiration embodied. The findings should assist in design decision making of selecting bathrooms for residential buildings. However, a balanced approach, taking into account other factors for such selection, is open for future investigation. Originality/value ā€“ The framework of strategies developed should improve the innovative design of bathrooms manufactured offsite and help maintain them for better lifecycle performance

    Strategic planning of UK housebuilders: case study of a major property developer

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    Current global economic crisis has presented the UK housebuilding industry with unprecedented period of volatility and uncertainty. In light of this, the development of strategic plans is becoming more critical for ensuring future competitiveness. Evidence from early literature suggests that firms in the development sector have not put sufficient emphasis on this management function. Further, there is little information on the manner by which housebuilders formulate their strategic plans, let al.one how the actors participate in the process of strategising. The research intends to contribute to this important but little understood area by presenting case study of a leading UK housebuilder, and a proposed activity framework, with a view to obtain a greater understanding of the strategic process within the organisation. Contrary to the popular belief, the finding provides evidence that longer-term thinking underpinned by sound and defendable business principles which are mobilised within organisation, does contribute to successful business in volatile and competitive environment of construction sector. Further, their longer-term thinking might have been responsible for their survival in the current difficult economic time. However, there is little evidence of any attempt to further utilise potential knowledge and creativity of staff. Further research should look at possible barriers to staff participation as professed by the activity framework

    Briefing: future trends in UK housebuilding

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    Homes have more influence on the way that people live and behave in society than anything else they spend their money on. A house usually represents an individualā€™s largest ever single investment, and is expected to last for decades, if not indefinitely. In order to make the most appropriate investment today, however, people need to know how they will be living and working in the future, both individually and as a society. A Royal Institution of Chartered Surveyors (RICS) report The Future of UK Housebuilding, published in December 2010, investigates and debates this issue. This briefing discusses the implications of the report for municipal engineers and others. In particular, the issues of sustainability, zero carbon dioxide, offsite technologies, technology changes and community impact are discussed

    Housebuilding business models and offsite construction take-up

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    The potential benefits of offsite construction have been widely reported. However, its takeā€up in UK construction has been lower than hoped. Previous studies have contributed solutions to accelerating takeā€up of offsite technology, albeit few examining the issue in business contexts. This paper contributes a novel approach to addressing offsite construction takeā€up in relation to business models. It reviews the challenges facing UK housebuilding business, maps conventional and emergent business models, and identifies factors capturing and creating value, centering on process and activities, risks, and finance. UK housebuilding is often decoupled from contracting, instead focusing on land acquisition, in response to the dominance of landā€use planning. The competitive edge potentially available from technological innovation is often rendered less important or prevalent. However, exemplars do exist regarding incorporating offsite into housebuildersā€™ business strategy, as well as adapting or creating business models to optimize such an approach. A conceptual model is presented here to help illustrate the multiā€faceted relationship between business models and offsite construction, which is examined drawing on a number of case studies of large UK housebuilders, the findings of which should help position future enquiries

    The future of offsite in housebuilding

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    UK housebuilding has evolved since the Second World War into a diverse and complex industry, continually trying to respond to multiple demands for quantity, quality, environmental sustainability and affordability. In response to this, offsite construction technologies seem to offer advantages of higher quality, faster build times and more cost certainty, as well as potential highvolume production and high environmental credentials. In order to investigate the potential for offsite in housebuilding, it is important that a long-term perspective is taken, informed by futures methodologies and techniques. The reasons for this are debated here, and we conclude that in order for the housebuilding industry to respond to the myriad challenges that lie ahead, it must take a longer-term view, and be more adaptable and responsive to changes, from both within the sector and in society generally

    A longitudinal investigation into utilising crosswall construction for multi-storey residential buildings

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    To address the under-supply and poor build quality of housing in the UK, the use of offsite technologies has been promoted. Precast concrete crosswall is an offsite technology encouraged for use for multi-storey developments. However, the uptake of crosswall is slow, which constitutes a risk to long-term housing delivery. This paper addresses this risk by revealing an insight into the utilisation of crosswall for multistorey residential buildings in the organisational context. The paper reports on longitudinal case study research of 20 crosswall buildings, consisting of 1930 apartments in total, constructed by a leading UK housebuilder in recent five years. The case study involved document analysis and personal interviews with the company and their supply chains. The rationale for utilising crosswall included considerations of design, technical, commercial, procurement and construction. The primary driver was simplicity from both procurement and contractual aspects, which enabled the developer to construct buildings up to 20 storeys without engaging specialist main contractors. Other benefits included reduced on-site duration, enhanced quality of finish, reduced waste, improved health and safety and cost savings, whilst issues existed in design, procurement and construction. To fully realise the potential benefits from utilising crosswall requires modifications to existing design process and supply chain management and cultural support to innovation and learning. Strategies are developed from the longitudinal learning process. They should encourage the uptake of crosswall and improve quality and efficiency of housing supply in the future

    Strategies for integrating the use of off-site production technologies in house building

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    Despite extensive research into attitudes and practice surrounding the uptake of off-site production technologies, there is limited understanding of how best to integrate their use into business processes at the organizational level. Drawing on an action-research case study with a leading U.K. house-building organization, this paper scrutinizes the processes through which off-site technologies were adopted and utilized. The use of off-site methods was fundamentally framed by the key stages and business milestone reviews of the house-building process, which together represented a complex and multilayered structure of business management. Five off-site reviews were aligned with the business processes. Strategies for integrating the use of off-site technologies are examined. It was crucial to establish an overall off-site strategy and integrate it into the process from land acquisition on. Organizational learning embraced the adoption of off-site methods, whereas extra reporting and management efforts introduced bureaucracy. Culture change was commonly perceived as difficult and painful. Earlier engagement with supply chains was advocated for favoring the off-site approach and improving business efficiency, whereas it also demanded greater commitment of the house builder to specific supply chains and therefore exposed the business to risks associated with planning and market changes. The strategies should facilitate building companiesā€™ strategic management of off-site technology

    Establishing and weighting decision criteria for building system selection in housing construction

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    A lack of value-based decision criteria leads to an inability to effectively compare prefabrication and off-site production with conventional construction, which inhibits the realization of benefits of off-site approaches. This paper develops value-based decision criteria and quantifies their relative importance for assessing building technologies systematically. The research employed a multimethodological strategy within a broad case-study-based design, with six large house-building organizations in the United Kingdom. These companies together accounted for more than one-tenth of new-build home completions in the United Kingdom. More than 50 criteria were developed, grouped under cost, time, quality, health and safety, sustainability, process, procurement, and regulatory and statutory acceptance. Cost was ranked most important, which, coupled with time and quality, predominated technology selection in these companies. Sustainability, process, and procurement were weighted lower, whereas health and safety and regulatory and statutory acceptance were deemed compulsory, hence offering no trade-off opportunity. A lack of incorporating innovative sustainable technology into corporate strategy was observed. The developed criteria and the systematic process should help house-building organizations manage technological innovation and hopefully achieve more informed corporate decisions

    Encouraging appropriate use of Offsite Production (OSP): perspectives of designers

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    The construction industry is being challenged to be more innovative in order to better satisfy the needs of clients and to enhance business competitiveness. Off-site production (OSP) offers significant opportunities for achieving improvements in process and productivity performance, especially in terms of delivering high quality, defect-free construction. Indeed, OSP is increasingly seen as a key part of the solution to improving the quality of construction and addressing skills constraints. However, many industry stakeholders have not realised that OSP requires systematic and strategic integration if these benefits are to be realised. In addition, many remain sceptical of the potential of OSP technology, particularly given the past failings in OSP practices. There is also an apparent lack of knowledge how to appropriately integrate different OSP techniques into the design process. After reviewing the concept of innovation, different levels of OSP techniques, and the current practices of UK architects and designers, this paper explores the drivers and barriers inherent in integrating OSP into the UK housing sector. This was examined through a range of interviews with architects and other designers. The findings reveal that barriers to the acceptance of OSP are centred around human perceptions grounded in the historical failure of off-site practices to deliver improved performance, technical difficulties (e.g. site specifics, delivery issues, interfacing problems, cost), lack of opportunities for benefiting from economies of scale, and the fragmented structure of the construction supply chain. This paper also discusses traditional and improved design processes (DFMA) in which major changes in the design role and the composition of the design team are called for. The findings of this study form part of a three-year ongoing study which aims to explore the successful integration of OSP in the UK housing sector
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