2,103 research outputs found

    Fade depth scaling with channel bandwidth

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    The dependence of small-scale fading on bandwidth is quantified experimentally in the 3.1–10.6 GHz band for indoor channels. The fade depth converges to 4 dB at 1 GHz bandwidth, with little reduction for further increase in bandwidth. A simple yet accurate empirical fade depth model is developed, enabling convenient evaluation of the link budget for a channel with given bandwidth

    Construction output modelling: a systematic review

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    Purpose: Construction economics scholars have emphasised the importance of construction output forecasting and have called for increased investment in infrastructure projects, due to the positive relationship between construction output and economic growth. However, construction output tends to fluctuate over time. Excessive changes in the volume of construction output have a negative impact upon the construction sector, such as liquidation of construction companies and job losses. Information gleaned from extant literature suggests that fluctuation in construction output is a global problem. Evidence indicates that modelling of construction output provides information for understanding the factors responsible for these changes. Methodology: An interpretivist epistemological lens is adopted to conduct a systematic review of published studies on modelling of construction output. A thematic analysis is then presented and the trends and gaps in current knowledge are highlighted. Findings: It is observed that interest rate is the most common determinant of construction output. Also revealed is that very little is known about the underlying factors stimulating growth in the volume of investment in maintenance construction works. Further work is required to investigate the efficacy of using non-linear techniques for construction output modelling. Originality: This study provides a contemporary mapping of existing knowledge relating to construction output and provides insights into gaps in current understanding that can be explored by future researchers

    A Case Study of Building Information Modelling Enabled ‘Information Totem’ for Operations and Maintenance Integration

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    This paper reports upon the use of a semi-automated toolkit to aid the development of as-built Building Information Model (BIM) (As-built model reflects on-site changes by the contractor to the original BIM) from inception to final construction. An observational case study of two educational ‘multi-storey’ facilities obtained primary data from project archives and focus group meetings with key design team members. The results demonstrate that the data requirements for both structures evolve post occupation because of stakeholder tacit knowledge accrued via building operation and usage. The semi-automated toolkit developed can readily access operations and maintenance (O&M) manuals, retrieve room specific data (such as categories of equipment or building element) within the as-built BIM and, assist in the navigation and coordination of amendments and changes throughout the construction phase. This paper provides useful practice-based information for practitioners to develop suitable BIM data structures for future information requirements throughout a building’s lifecycle. The inherent value of the semi-automated toolkit resides in the facilitation of ease of handover for the Facilities Management team during the O&M stages

    Automating construction manufacturing procedures using BIM digital objects (BDOs): Case study of knowledge transfer partnership project in UK

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    Purpose This paper aims to present a novel proof-of-concept framework for implementing building information modeling (BIM) Digital Objects (BDO) to automate construction product manufacturers’ processes and augment lean manufacturing. Design/methodology/approach A mixed interpretivist and post-positivist epistemological lens is adopted to pursue the proof-of-concept’s development. From an operational perspective, a synthesis of literature using interpretivism provides the foundation for deductive research inquiry implemented within a case study approach. Within the case study, participatory action research (PAR) is implemented to test the proof of concept via three “waterfall” research phases, namely, literature diagnosis and BIM package selection, BDO development and validation and evaluation. Findings The findings illustrate that a BDO (which represents the digital twin of manufacturing products) can augment and drive automation processes and workflows for construction product manufacturers within a contractor’s supply chain. The developed framework illustrates the benefits of a BDO, by reducing the number of manufacturing processes to effectively eliminate early errors in the model, generates financial savings and reduces material wastage. Originality/value This research provides a seminal case study that implements BDO to automate construction product manufacturing processes and demonstrates the utilisation of BDO at an operational (vis-à-vis theoretical) level. Future research is proposed to implement a longitudinal approach to measure and report upon the success (or otherwise) of the proof of concept when implemented on fabrications and shop floor procedures

    FLIC-Overlap Fermions and Topology

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    APE smearing the links in the irrelevant operators of clover fermions (Fat-Link Irrelevant Clover (FLIC) fermions) provides significant improvement in the condition number of the Hermitian-Dirac operator and gives rise to a factor of two savings in computing the overlap operator. This report investigates the effects of using a highly-improved definition of the lattice field-strength tensor F_mu_nu in the fermion action, made possible through the use of APE-smeared fat links in the construction of the irrelevant operators. Spurious double-zero crossings in the spectral flow of the Hermitian-Wilson Dirac operator associated with lattice artifacts at the scale of the lattice spacing are removed with FLIC fermions composed with an O(a^4)-improved lattice field strength tensor. Hence, FLIC-Overlap fermions provide an additional benefit to the overlap formalism: a correct realization of topology in the fermion sector on the lattice.Comment: Lattice2002(chiral

    A Framework for Smart Building Technologies Implementation in the Ghanaian Construction Industry: A PLS-SEM Approach

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    This study sought to identify the dimensions and the significant critical factors capable of enhancing Smart Building Technologies' (SBTs') implementation for smart building projects in developing countries. A desk literature review is first conducted to identify and categorize the potential factors. It is further analyzed using partial least square structural equation modelling (PLS-SEM) based on 227 valid data from experts in Ghana. The study revealed four underlying dimensions (i.e., ‘processes and control'[PC], ‘people and skills'[PS], ‘methods and techniques'[MT], and ‘knowledge sharing'[KS]) consisting 14 significant critical factors capable of enhancing SBTs implementation for smart building projects, with the top three comprising ‘appropriate procedures/practices for managing smart building projects (MT3)', ‘appropriate tools/techniques to guide smart building projects to their delivery (MT2)', and ‘skills and experience required to pick project team members for smart building projects (PS1)’. Further analysis with PLS-SEM revealed a significant positive effect of the four underlying dimensions and their positive interrelationships toward framework development. Besides the unique contribution of this study to the knowledge body, it also provides project managers and a construction design team with a structured knowledge of the skills, expertise, attitudes, decision-making, processes, control mechanisms, and effective delivery of smart building projects in developing countries

    The prevalence and impact of Fusarium Head Blight pathogens and mycotoxins on malting barley quality in UK

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    Fusarium head blight (FHB) caused by Fusarium and Microdochium species can significantly affect the yield of barley grain as well as the quality and safety of malt and beer. The present study provides new knowledge on the impacts of the FHB pathogen complex on the malting and brewing quality parameters of naturally infected barley. Quantitative real-time PCR and liquid chromatography double mass spectrometry were used to quantify the predominant FHB pathogens and Fusarium mycotoxins, respectively, in commercially grown UK malting barley samples collected between 2007 and 2011. The predominant Fusarium species identified across the years were F. poae, F. tricinctum and F. avenaceum. Microdochium majus was the predominant Microdochium species in 2007, 2008, 2010 and 2011 whilst Microdochium nivale predominated in 2009. Deoxynivalenol and zearalenone quantified in samples collected between 2007 and 2009 were associated with F. graminearum and F. culmorum, whilst HT-2 and T-2, and nivalenol in samples collected between 2010 and 2011 correlated positively with F. langsethiae and F. poae, respectively. Analysis of the regional distribution and yearly variation in samples from 2010 to 2011 showed significant differences in the composition of the FHB species complex. In most regions (Scotland, the South and North of England) the harvest in 2010 had higher concentrations of Fusarium spp. than in 2011, although no significant difference was observed in the Midlands between the two years. Microdochium DNA was significantly higher in 2011 and in the North of England and Scotland compared to the South or Midlands regions. Pathogens of the FHB complex impacted negatively on grain yield and quality parameters. Thousand grain weight of malting barley was affected significantly by M. nivale and M. majus whilst specific weight correlated negatively with F. avenaceum and F. graminearum. To determine the impact of sub-acute infections of the identified Fusarium and Microdochium species on malting and brewing quality of naturally infected samples, selected malting barley cultivars (Optic, Quench and Tipple) were micromalted and subjected to malt and wort analysis of key quality parameters. F. poae and M. nivale decreased germinative energy and increased water sensitivity of barley. The fungal biomass of F. poae and F. langsethiae correlated with increased wort free amino nitrogen and with decreased extract of malt. DNA of M. nivale correlated with increased malt friability as well as decreased wort filtration volume. The findings of this study indicate that the impact of species such as the newly emerging F. langsethiae, as well as F. poae and the two non-toxigenic Microdochium species should be considered when evaluating the quality of malting barley. © 2014

    Collaborative procurement and private-sector housebuilding and refurbishment works: A pilot study investigation of the UK

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    Purpose Framed as a pilot study, the purpose of this paper is to study the perceived appropriateness of an existing collaborative procurement procedures (CPP) framework from the housebuilder’s perspective; seeking to improve its utility and stimulate further exploration. Design/methodology/approach Informed by an existing CPP framework, and conducted by a UK-based development professional, four in-depth semi-structured interviews were undertaken with senior housebuilding practitioners from London and surrounding counties. A qualitative analysis was then conducted for this sociological study. Findings Perceived appropriateness of the framework was high; however, a number of procedural improvements were identified, along with limitations. Future studies are recommended including the influence upon project performance of groundworker integration at the design stage. Research limitations/implications Limited to four interviews from one regional area, the study is an initial insight into the appropriateness of an existing CPP framework. Insights into why CP uptake is marginal within housebuilding were also gained. The research purpose was achieved but by offering a self-reflection upon practice (vis-à-vis wider generalisations) the findings provide a springboard for further studies. Practical implications The research identifies with current practice, industry perceptions, and paths towards improving the utility of the CPP framework. Social implications This study offers insights into the perceptions of private housebuilding practitioners of their own practices and the factors they find challenging within the social constructs of their industry. Originality/value This research constitutes one of the first studies in the UK to examine the CPP framework from the perspective of the private housebuilder and is undertaken with the express purpose of furthering that framework’s utility
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