Change orders are common and clearly noticeable in Jordanian construction industry. Several studies have identified change orders as significant problem in Jordanian construction projects, and they mainly cause delay ...Change orders are common and clearly noticeable in Jordanian construction industry. Several studies have identified change orders as significant problem in Jordanian construction projects, and they mainly cause delay and cost overrun. This situation spurs the researchers for investigating the significant causes of change orders in construction projects. Thus, this paper aims to determine the main causes of change orders in the Jordanian construction private sector which responsible for significant cost overrun. Both qualitative and quantitative methods, i.e. interview and questionnaire techniques, were used to achieve this aim. Interviews were conducted as the first stage of data collection, and the results formed the basis of the questionnaire, which was distributed across the Jordanian construction sector. Content analysis was used to analyse the interview responses, while factor analysis, correlation and the Severity Index (SI) were used to analyse the questionnaire results. The findings identified three main categories of causes of change orders in private sector, namely engineering causes, causes related to the client, and circumstances of the project, with sub-causes in each category which are related to each other in significant ways and which affect each other.展开更多
Length and concise structure of fuzzy logic reasoning program and its real-time reasoning characteris-tic have their effect on the performance of a digital single-chip fuzzy controller. The control effect of a digital...Length and concise structure of fuzzy logic reasoning program and its real-time reasoning characteris-tic have their effect on the performance of a digital single-chip fuzzy controller. The control effect of a digitalfuzzy controller based on looking up fuzzy control responding table is only relative to the table and not relative tothe fuzzy control rules in the practical control process. Aiming at above problem and having combined fuzzy log-ic reasoning with digital operational characteristics of a single-chip microcomputer, functioning-fuzzy-subset in-ference (FFSI) in binary, in which triangle membership functions of error and error-in-change are all represen-ted in binary and singleton membership functions of control variable is binary too, has been introduced. The cir-cuit principle plans of a single-chip fuzzy controller have been introduced for development of its hardware, andthe primary program structure, fuzzy logic reasoning subroutine, serial communication subroutine with PC andreliability design of the fuzzy controller are all discussed in detail. The control of indoor temperature by a fuzzycontroller has been conducted using a testing-room thermodynamic system. Research results show that the FFSIin binary can exercise a concise fuzzy control in a single-chip fuzzy controller, and the fuzzy controller is there-fore reliable and possesses a high performance-price ratio.展开更多
The combination of urbanization and global warming leads to urban overheating and compounds the frequency and intensity of extreme heat events due to climate change.Yet,the risk of urban overheating can be mitigated b...The combination of urbanization and global warming leads to urban overheating and compounds the frequency and intensity of extreme heat events due to climate change.Yet,the risk of urban overheating can be mitigated by urban green-blue-grey infrastructure(GBGI),such as parks,wetlands,and engineered greening,which have the potential to effectively reduce summer air temperatures.Despite many reviews,the evidence bases on quantified GBGI cooling benefits remains partial and the practical recommendations for implementation are unclear.This systematic literature review synthesizes the evidence base for heat mitigation and related co-benefits,identifies knowledge gaps,and proposes recommendations for their implementation to maximize their benefits.After screening 27,486 papers,202 were reviewed,based on 51 GBGI types categorized under 10 main divisions.Certain GBGI(green walls,parks,street trees)have been well researched for their urban cooling capabilities.However,several other GBGI have received negligible(zoological garden,golf course,estuary)or minimal(private garden,allotment)attention.The most efficient air cooling was observed in botanical gardens(5.0±3.5℃),wetlands(4.9±3.2℃),green walls(4.1±4.2℃),street trees(3.8±3.1℃),and vegetated balconies(3.8±2.7℃).Under changing climate conditions(2070–2100)with consideration of RCP8.5,there is a shift in climate subtypes,either within the same climate zone(e.g.,Dfa to Dfb and Cfb to Cfa)or across other climate zones(e.g.,Dfb[continental warm-summer humid]to BSk[dry,cold semi-arid]and Cwa[temperate]to Am[tropical]).These shifts may result in lower efficiency for the current GBGI in the future.Given the importance of multiple services,it is crucial to balance their functionality,cooling performance,and other related co-benefits when planning for the future GBGI.This global GBGI heat mitigation inventory can assist policymakers and urban planners in prioritizing effective interventions to reduce the risk of urban overheating,filling research gaps,and promoting community resilience.展开更多
文摘Change orders are common and clearly noticeable in Jordanian construction industry. Several studies have identified change orders as significant problem in Jordanian construction projects, and they mainly cause delay and cost overrun. This situation spurs the researchers for investigating the significant causes of change orders in construction projects. Thus, this paper aims to determine the main causes of change orders in the Jordanian construction private sector which responsible for significant cost overrun. Both qualitative and quantitative methods, i.e. interview and questionnaire techniques, were used to achieve this aim. Interviews were conducted as the first stage of data collection, and the results formed the basis of the questionnaire, which was distributed across the Jordanian construction sector. Content analysis was used to analyse the interview responses, while factor analysis, correlation and the Severity Index (SI) were used to analyse the questionnaire results. The findings identified three main categories of causes of change orders in private sector, namely engineering causes, causes related to the client, and circumstances of the project, with sub-causes in each category which are related to each other in significant ways and which affect each other.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 59908001)Multidiscipline Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. MD200030)
文摘Length and concise structure of fuzzy logic reasoning program and its real-time reasoning characteris-tic have their effect on the performance of a digital single-chip fuzzy controller. The control effect of a digitalfuzzy controller based on looking up fuzzy control responding table is only relative to the table and not relative tothe fuzzy control rules in the practical control process. Aiming at above problem and having combined fuzzy log-ic reasoning with digital operational characteristics of a single-chip microcomputer, functioning-fuzzy-subset in-ference (FFSI) in binary, in which triangle membership functions of error and error-in-change are all represen-ted in binary and singleton membership functions of control variable is binary too, has been introduced. The cir-cuit principle plans of a single-chip fuzzy controller have been introduced for development of its hardware, andthe primary program structure, fuzzy logic reasoning subroutine, serial communication subroutine with PC andreliability design of the fuzzy controller are all discussed in detail. The control of indoor temperature by a fuzzycontroller has been conducted using a testing-room thermodynamic system. Research results show that the FFSIin binary can exercise a concise fuzzy control in a single-chip fuzzy controller, and the fuzzy controller is there-fore reliable and possesses a high performance-price ratio.
基金This work has been commissioned by the UKRI(EPSRC,NERC,AHRC)funded by RECLAIM Network Plus project(EP/W034034/1,EP/W033984)under its synthesis review seriesThe following authors acknowledge the funding received through their grants:P.K.and L.J.(NE/X002799/1,NE/X002772/1),L.J.(H2020 REGREEN,EU Grant agreement No.821016,2021YFE93100),G.M.L.(FAPESP 2019/08783-0),C.D.F.R.(EP/R017727),L.M.(ARC Grant No.IC220100012),H.G.(RGC Grant No.C5024-21G),M.F.A.and E.D.F.(FAPESP Grant No.2016/18438-0,2022/02365-5),S.J.C.(NSFC Grant No.52225005),R.Y.(NSFC Grant No.52278090),F.W.(NKP Grant No.2020YFC180700),J.E.(NE/X000443/1),and F.C.(NE/M010961/1,NE/V002171/1).The authors thank Andrea Sofia Majjul Fajardo for her contribution to the initial design of certain figures.We also thank the team members of GCARE and its Guildford Living Lab(GLL),as well as the participants in the RECLAIM Network Plus Horizon Scanning Workshop.
文摘The combination of urbanization and global warming leads to urban overheating and compounds the frequency and intensity of extreme heat events due to climate change.Yet,the risk of urban overheating can be mitigated by urban green-blue-grey infrastructure(GBGI),such as parks,wetlands,and engineered greening,which have the potential to effectively reduce summer air temperatures.Despite many reviews,the evidence bases on quantified GBGI cooling benefits remains partial and the practical recommendations for implementation are unclear.This systematic literature review synthesizes the evidence base for heat mitigation and related co-benefits,identifies knowledge gaps,and proposes recommendations for their implementation to maximize their benefits.After screening 27,486 papers,202 were reviewed,based on 51 GBGI types categorized under 10 main divisions.Certain GBGI(green walls,parks,street trees)have been well researched for their urban cooling capabilities.However,several other GBGI have received negligible(zoological garden,golf course,estuary)or minimal(private garden,allotment)attention.The most efficient air cooling was observed in botanical gardens(5.0±3.5℃),wetlands(4.9±3.2℃),green walls(4.1±4.2℃),street trees(3.8±3.1℃),and vegetated balconies(3.8±2.7℃).Under changing climate conditions(2070–2100)with consideration of RCP8.5,there is a shift in climate subtypes,either within the same climate zone(e.g.,Dfa to Dfb and Cfb to Cfa)or across other climate zones(e.g.,Dfb[continental warm-summer humid]to BSk[dry,cold semi-arid]and Cwa[temperate]to Am[tropical]).These shifts may result in lower efficiency for the current GBGI in the future.Given the importance of multiple services,it is crucial to balance their functionality,cooling performance,and other related co-benefits when planning for the future GBGI.This global GBGI heat mitigation inventory can assist policymakers and urban planners in prioritizing effective interventions to reduce the risk of urban overheating,filling research gaps,and promoting community resilience.
