Cost Climate Survey Scale in Construction:Development and Empirical Research

To develop the cost climate survey scale( CCSS) used in construction enterprises,the design concepts,principles and the process diagrams of CCSS are proposed.Through questionnaire investigation and expert interviews,314 projects are established and the CCSS that is made up of 7 dimensions framework and 30 levels is preliminarily determined.After categorized merger,pre-test analysis and multiple items refining,16 projects of CCSS are eventually compiled.In order to verify the credibility and validity of the CCSS,200 employees in Qinhuangdao construction company as the samples are tested.SPSS 21.0 is used to analyze the reliability,validity and rationality of level divisions,and Amos 22.0 is for analyzing the degree of model adaptation in this survey.Finally,the current cost climate situation of the construction site in the company is evaluated,the deficiencies of the cost culture of the construction site are pointed out.This study shows that strengthening the cost knowledge training has a significant positive effect on the cost climate cognition of the employees.Nevertheless,accumulation of work experience has a dual impact on that.The CCSS is not only an important foundation for the cost climate research and its theoretical development,but also the premise of the cost climate quantitative research.An appropriate CCSS,to some extent,can reflect the cognitive level of all kinds of employees in one enterprise and cost savings degree of the enterprise in a certain time.The development of CCSS reflects the originality and interactivity,and fills a blank of the CCSS in construction,which is considered to be an effective tool for cost climate research in construction.

Optimisation of Thermal Comfort of Building in a Hot and Dry Tropical Climate: A Comparative Approach between Compressed Earth/Concrete Block Envelopes

Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.

A rapid assessment method for calculating the drag coefficient in wave attenuation by vegetation

Vegetation in wetlands is a large-scale nature-based resource that can provide multiple benefits to human beings and the environment,such as wave attenuation in coastal zones.Traditionally,there are two main calibration approaches to calculate the attenuation of wave driven by vegetation.The first method is a straightforward one based on the exponential attenuation of wave height in the direction of wave transmission,which,however,overlooks the crucial drag coefficient(CD).The other method is in accordance with more complicate equations for predicting the damping factor,which is regarded as a function of CD.In this study,a new relation,combining these above two conventional approaches,is proposed to predict the CD in an operative approach.Results show that values yielded by the new assessment method perform a strong linear relationship with a collection of historical observations,with a promising R2 value of 0.90.Besides,the linear regression derives a new predictive equation for the bulk drag coefficient.Additionally,a calibrated value of 4 for the empirical plant drag coefficient(CP)is revealed.Overall,this new equation,with the superiority of the convenient exponential regression,is expected to be a rapid assessment method for calculating wave attenuation by vegetation and predicting the drag coefficient.

Double-skin façade simulation with computational fluid dynamics:A review of simulation trends,validation methods and research gaps

Dynamic simulation of a double-skin façade(DSF)with computational fluid dynamics(CFD)can be challenging due to the lack of validated models and benchmarking datasets.Furthermore,there is a lack of consensus in the scientific community on what constitutes a successfully validated DSF model.The present review study identifies simulation trends and research gaps for DSFs simulated with CFD.Additionally,this article presents a series of CFD simulations in which key aspects of the DSF modelling are varied:2D or 3D modelling approaches,turbulence viscosity models(TVMs),radiation models,and wall function.These simulation results are compared to the empirical data(both temperature and velocity fields)of a benchmark test with laboratory-controlled boundary conditions.This analysis shows that using the k-εRNG model with enhanced wall treatment and surface-to-surface(S2S)radiation model yields the best results for the 2D case of natural convection flow.Moreover,it is shown that accounting for the velocity field in the validation process is essential to ensure the suitability of a model.Finally,the authors advocate for the use of selected dimensionless numbers to improve the comparability of the different DSF scientific studies.This would also help to identify relevant experimental datasets for validation and suitable CFD simulation settings for specific DSF cases.

A study of hybrid prediction method for ship parametric rolling

The parametric rolling（PR） in the head or following waves has been considered as one of the main stability failure modes in the development of the 2nd generation Intact Stability criterion by the International Maritime Organization（IMO）.According to previous studies,the estimation methods of the roll damping affect the prediction of the PR significantly,and most of them are based on experiment data or Ikeda＇s empirical formula.The accuracy of the estimation method for the roll damping could be a key aspect for the validity of its prediction for the full scale ship.In this research,a hybrid prediction method is developed for the numerical prediction of the parametric rolling when experiment data are not available for the roll damping.Comparison study is also carried out between the hybrid method and a nonlinear dynamics method,where the roll damping is estimated by the simplified Ikeda＇s method and the direct CFD prediction method in a direct non-linear simulation based on the 3-D CFD approach in the model scale.It is shown that the results of the hybrid method are in satisfactory agreements with the model experiment results,and the method can be used for analysis especially at the early design stage where experiment data are often not available.

DUSM： A Method for Requirements Specification and Refinement Based on Disciplined Use Cases and Screen Mockups

In this work, we present DUSM （Disciplined Use Cases with Screen Mockups）, a novel method for describing and refining requirements specifications based on disciplined use cases and screen mockups. Disciplined use cases are characterized by a quite stringent template to prevent common mistakes, and to increase the quality of the specifications. Use cases descriptions are formulated in a structured natural language, which allows to reach a good level of precision, avoiding the need for further notations and complex models. Screen mockups are precisely associated with the steps of the use cases scenarios and they present the corresponding GUIs （graphical user interfaces） as seen by the human actors before/after the steps executions, improving the comprehension and the expression of the non-functional requirements on the user interface. DUSM has been proposed and fine-tuned during several editions of a software engineering course at the University of Genova. Then, by means of a series of case studies and experiments, we validated the method and evaluated： 1） its effectiveness in improving the comprehension and, in general, the quality of the produced requirements specification, and 2） its applicability in the industry, where the method has been found useful and not particularly onerous.

A review of validation methods for building energy modeling programs

Building energy simulation analysis plays an important supporting role in the conservation of building energy.Since the early 1980s,researchers have focused on the development and validation of building energy modeling programs(BEMPs)and have basically formed a set of systematic validation methods for BEMPs,mainly including analytical,comparative,and empirical methods.Based on related papers in this field,this study systematically analyzed the application status of validation methods for BEMPs from three aspects,namely,sources of validation cases,comparison parameters,and evaluation indicators.The applicability and characteristics of the three methods in different validation fields and different development stages of BEMPs were summarized.Guidance were proposed for researchers to choose more suitable validation methods and evaluation indicators.In addition,the current development trend of BEMPs and the challenges faced by validation methods were investigated,as well as the existing progress of current validation methods under this trend was analyzed.Subsequently,the development direction of the validation method was clarified.