Computer vision-based inspection methods show promise for automating post-earthquake building inspections.These methods survey a building with unmanned aerial vehicles and automatically detect damage in the collected ...Computer vision-based inspection methods show promise for automating post-earthquake building inspections.These methods survey a building with unmanned aerial vehicles and automatically detect damage in the collected images.Nevertheless,assessing the damage′s impact on structural safety requires localizing damage to specific building components with known design and function.This paper proposes a BIM-based automated inspection framework to provide context for visual surveys.A deep learning-based semantic segmentation algorithm is trained to automatically identify damage in images.The BIM automatically associates any identified damage with specific building components.Then,components are classified into damage states consistent with component fragility models for integration with a structural analysis.To demonstrate the framework,methods are developed to photorealistically simulate severe structural damage in a synthetic computer graphics environment.A graphics model of a real building in Urbana,Illinois,is generated to test the framework;the model is integrated with a structural analysis to apply earthquake damage in a physically realistic manner.A simulated UAV survey is flown of the graphics model and the framework is applied.The method achieves high accuracy in assigning damage states to visible structural components.This assignment enables integration with a performance-based earthquake assessment to classify building safety.展开更多
The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional method...The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional methods for creating digital surface models are insufficient to reflect the details of earth’s features. These models only represent three-dimensional objects in a single texture and fail to offer a realistic depiction of the real world. Furthermore, the need for current and precise geographic information regarding urban areas has been increasing significantly. This study proposes a new technique to address this problem, which involves integrating remote sensing, Geographic Information Systems (GIS), and Architecture Environment software environments to generate a detailed three-dimensional model. The processing of this study starts with: 1) Downloading high-resolution satellite imagery; 2) Collecting ground truth datasets from fieldwork; 3) Imaging nose removing; 4) Generating a Two-dimensional Model to create a digital surface model in GIS using the extracted building outlines; 5) Converting the model into multi-patch layers to construct a 3D model for each object separately. The results show that the 3D model obtained through this method is highly detailed and effective for various applications, including environmental studies, urban development, expansion planning, and shape understanding tasks.展开更多
The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturin...The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturing the details of Earth’s features. This is because they represent only three-dimensional objects in a single texture and do not provide a realistic representation of the real world. Additionally, there is a growing demand for up-to-date and accurate geo-information, particularly in urban areas. To address this challenge, a new technique is proposed in this study that involves integrating remote sensing, Geographic Information System, and Architecture Environment software to generate a highly-detailed three-dimensional model. The method described in this study includes several steps such as acquiring high-resolution satellite imagery, gathering ground truth data, performing radiometric and geometric corrections during image preprocessing, producing a 2D map of the region of interest, constructing a digital surface model by extending the building outlines, and transforming the model into multi-patch layers to create a 3D model for each object individually. The research findings indicate that the digital surface model obtained with comprehensive information is suitable for different purposes, such as environmental research, urban development and expansion planning, and shape recognition tasks.展开更多
In order to improve the efficiency of 3D near-surface velocity model building, we develop a layer-stripping method using seismic first-arrival times. The velocity model within a Common Mid-Point (CMP) gather is assu...In order to improve the efficiency of 3D near-surface velocity model building, we develop a layer-stripping method using seismic first-arrival times. The velocity model within a Common Mid-Point (CMP) gather is assumed to be stratified into thin layers, and the velocity of each layer var- ies linearly with depth. The thickness and velocity of the top layer are estimated using minimum-offset first-arrival data in a CMP gather. Then the top layer is stripped and the second layer becomes a new top layer. After removing the effect of the top layer from the former first-arrival data, the new first-arrival data are obtained and then used to estimate the parameters of the second layer. In this manner, the velocity model, being regarded as that at a CMP location, is built layer-by-layer from the top to the bottom. A 3D near-surface velocity model is then formed using the velocity models at all CMP locations. The tests on synthetic and observed seismic data show that the layer-stripping method can be used to build good near-surface velocity models for static correction, and its computation speed is approximately hundred times faster than that of grid tomography.展开更多
Composting is a suitable low-cost strategy to transform animal waste into a stabilized end product,and the airflow field in the pile affects the fermentation states.For piles in the aeration weak zone,anaerobic fermen...Composting is a suitable low-cost strategy to transform animal waste into a stabilized end product,and the airflow field in the pile affects the fermentation states.For piles in the aeration weak zone,anaerobic fermentation may happen as the lack of oxygen.While in practice,due to the extremely low speed and harsh condition,the airflow field was scarcely researched.This study adopted Computational Fluid Dynamics(CFD)to investigate the airflow field in the compost pile.A three-dimensional CFD model was built;the compost pile in this model was simplified as porous media;unstructured mesh was adopted to discretize the geometric model;standard k-εmodel and SIMPLE scheme were employed for numerical methods.The CFD model was validated with the field experiment in the cooling period.Then the model was applied to research the airflow field in the pile with increased pipe diameter.Results showed that it was feasible to investigate the airflow field in the pile with CFD.For boundary conditions in the CFD model,treating the compost pile as a homogeneous porous media is reasonable.The CFD model was successfully validated by the field measurement(the average relative difference between the simulated and measured air speed was within 10%).Airflow in the existing compost pile showed nonuniform distribution with stagnation and vortex zones;the turbulence intensities were 3.57 and 1.43 for the airflow in the pile and the reactor,respectively.When pipe diameter increased,the airflow distribution uniformity in the pile was improved significantly.With diameter raising to 0.04 m,the turbulence intensity decreased to 1.54 and 0.42 for the airflow in the pile and the reactor,respectively.The CFD model developed in this research can provide qualitative and quantitative analyses of the airflow field in compost piles,and can be a theoretical basis for the aeration system design.展开更多
Underground pipeline networks constitute a major component of urban infrastructure,and thus,it is imperative to have an efficient mechanism to manage them.This study introduces a secondary development system to effici...Underground pipeline networks constitute a major component of urban infrastructure,and thus,it is imperative to have an efficient mechanism to manage them.This study introduces a secondary development system to efficiently model underground pipeline networks,using the building information modeling(BIM)-based software Revit.The system comprises separate pipe point and tubulation models.Using a Revit application programming interface(API),the spatial position and attribute data of the pipe points are extracted from a pipeline database,and the corresponding tubulation data are extracted from a tubulation database.Using the Family class in Revit API,the cluster in the self-built library of pipe point is inserted into the spatial location and the attribute data is added;in the same way,all pipeline instances in the pipeline system are created.The extension and localization of the model accelerated the modeling speed.The system was then used in a real construction project.The expansion of the model database and rapid modeling made the application of BIM technology in three-dimensional visualization of underground pipeline networks more convenient.Furthermore,it has applications in pipeline engineering construction and management.展开更多
An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended und...An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS.展开更多
Energy consumption reduction efforts in the residential buildings sector represent socio-economical, technological and environmental preoccupations which justify advanced scientific research. These lead to use inverse...Energy consumption reduction efforts in the residential buildings sector represent socio-economical, technological and environmental preoccupations which justify advanced scientific research. These lead to use inverse models to describe thermal behavior and to evaluate the energy consumption of buildings. Their principal goal is to provide supporting evidence of enhanced energy performances and predictions. More specifically, research questions are related to building thermal modeling which is the most appropriate in a smart grid context. In this context, the models are reviewed according to three categories. The first category is based on physical and basic principle modeling (white-box). The second offers a much simpler structure which is the statistical models (black-box). The black-box is used for prediction of energy consumption and heating/ cooling demands. Finally, the third category is a hybrid method (grey-box), which uses both physical and statistical modeling techniques. In this paper, we propose a detailed review and simulation of the main thermal building models. Our comparison and simulation results demonstrate that the grey-box is the most effective model for management of buildings energy consumption.展开更多
Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans....Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans. Researchers have made numerous efforts to accurately calculate emissions to reduce the life cycle carbon emissions of residential buildings. Nevertheless, there are still difficulties in quickly estimating carbon emissions in the design stage without specific data. To fill this gap, the study, based on Life Cycle Assessment (LCA) and Building Information Modeling (BIM), proposed a quick method for estimating Building’s Life Cycle Carbon Emissions (BLCCE). Taking a hospital building in Chuzhou City, Anhui Province, China as an example, it tested its possibility to estimate BLCCE. The results manifested that: 1) the BLCCE of the project is 40,083.56 tCO2-eq, and the carbon emissions per square meter per year are 119.91 kgCO2-eq/(m2·y);2) the stage of construction, operational and demolition account for 7.90%, 91.31%, and 0.79% of BLCCE, respectively;3) the annual carbon emissions per square meter of hospital are apparently higher than that of villa, residence, and office building, due to larger service population, longer daily operation time, and stricter patient comfort requirements. Considering the lack of BLCCE research in Chinese hospitals, this case study will provide a valuable reference for the estimated BLCCE of hospital building.展开更多
Dengue community capacity (DCC) is important for developing a sustainable approach to over-coming the problem of dengue. The objectives were 1) to develop and 2) evaluate a dengue community capacity building model for...Dengue community capacity (DCC) is important for developing a sustainable approach to over-coming the problem of dengue. The objectives were 1) to develop and 2) evaluate a dengue community capacity building model for the leader and non-leader group in three communities selected by purposive technique. A mixed method research design was used employing both qualitative and quantitative methods with qualitative studies conducted for community capacity building model: assessment, planning, implementation, and evaluation. DCC level was assessed by the Dengue Community Capacity Assessment Tool (DCCAT) including larval indices, and morbidity and mortality rate. To analyze the differences of the leader and non-leader’s DCC levels both pre and post-interventions in each model, the Mann-Whitney and Independent T-test were used and to analyze the difference of the DCC level among the three models (Ban Mon, Ban Nangpraya and Ban Kang), the Kruskal-Wallis Test, ANOVA, and ANCOVA were used. The findings showed that there were some differences among the three models in dengue community capacity building in terms model. The participants consisted of leader (n = 26, 24 and 28) and non-leader groups (n = 200, 215 and 176 respectively). The DCC levels of both leader and non-leader groups increased post-intervention in each model (p < 0.001) and in all three models, showing a statistically significant difference between pre and post-intervention (p < 0.001). Ban Kang model demonstrated the highest DCC levels of leader and non-leader groups, the lowest larval indices (HI, BI, and CI), and no dengue morbidity. In contrast, Ban Mon and Ban Nangpraya model showed low DCC level in both leader and non-leader groups, a high rate of larval indices and high dengue morbidity rate. However, there was no mortality rate in three areas. The conclusion indicates that the model with a high DCC level showed low risk on the dengue index both entomological and epidemiology index. The model of dengue community capacity building for dengue solution was sustainability not only needs to be maintained DCC levels but also increased dependent upon the contexts of each community.展开更多
To comply with the strategic goal of "mass entrepreneurship and innovation",universities and col eges adjusted the discipline cultivation objective to be cultivation of innovational and enterprising talents....To comply with the strategic goal of "mass entrepreneurship and innovation",universities and col eges adjusted the discipline cultivation objective to be cultivation of innovational and enterprising talents.Innovational and enterprising talents are inseparable from creative thinking,while the cultivation of creative thinking is the basis of cultivation of innovational and enterprising talents.This paper discussed cultivation of students' creative thinking through making building models in basic course of architectural design.Besides,it analyzed the relation between making of building models and creative thinking from divergent thinking,multi-directional thinking,element changing thinking,conversion thinking,and reverse thinking.It is expected to cultivate students' creative thinking through building models,to lay a solid foundation for architectural design courses,and to provide more architectural designers with more solid foundation and creative thinking.展开更多
Building Information Modelling (BIM) is a technology and a process that has brought changes in the construction’s traditional procurement system. Kenya lacks contractual guidelines on implementation of BIM;this makes...Building Information Modelling (BIM) is a technology and a process that has brought changes in the construction’s traditional procurement system. Kenya lacks contractual guidelines on implementation of BIM;this makes the adoption of BIM slow and difficult. Previous research has identified a gap in contractual relationships, roles and resulting risks. The objectives of this study were to investigate BIM adoption in Nairobi and to investigate the influence of BIM on Engineering Contract Management (ECM)</span><span style="font-family:Verdana;"> in Nairobi Kenya</span><span style="font-family:Verdana;">. The survey research was a descriptive study with 175 responsive questionnaires. Respondents comprised of Civil Engineers, Construction Project Managers, Architects, Quantity Surveyors, Contractors and Facility Managers. Data was collected through self-administered questionnaire and in-depth interview. Descriptive analytics, correlation and Exploratory factor analysis methods were used to analyse quantitative data. Qualitative data was analysed thematically. It emerged that adoption level was at 56.6% and shallow understanding of BIM capabilities remains to be a barrier to its adoption and implementation. It also emerged that BIM improves ECM;when time, cost, quality, collaboration and return on investment improve, ECM becomes easier. Latent factors found in BIM and ECM relationship were Legal Implications, awareness and knowledge, efficiency, versatility, mandate and leadership, and competitiveness. Further, the study found out that BIM influence on ECM demands for establishment of standards, guidelines, policy, legal framework, and regulations, which can be achieved by amending the public procurement act which dictates the operation of all the other standard forms of contract. Further research should be conducted to measure whether the understanding of BIM had positively improved.展开更多
The location and nature of the moisture leakages are sometimes difficult to detect. Moreover, the relation between observed inside surface moisture patterns and where the moisture enters the construction is often not ...The location and nature of the moisture leakages are sometimes difficult to detect. Moreover, the relation between observed inside surface moisture patterns and where the moisture enters the construction is often not clear. The objective of this paper is to investigate inverse modeling techniques as a tool for the detection of moisture leakage locations in building constructions from inside surface moisture patterns. It is concluded that although the presented methodology is promising, more research is needed to confirm its usability.展开更多
One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for stru...One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.展开更多
Global concerns toward environmental issues have induced growing demand for new approaches in the construction because of its considerable impact on the environment and use of natural resources. Through using construc...Global concerns toward environmental issues have induced growing demand for new approaches in the construction because of its considerable impact on the environment and use of natural resources. Through using construction sustainability tools, methods and techniques, a greener design can be applied during various building phases. In this connection, it is argued that the analytical and integrated models applied by Building Information Modelling (BIM) may also facilitate this process to be performed more efficiently. BIM and construction sustainability are quite different initiatives, but both have received much attention in recent years in the architecture, engineering and construction (AEC) industry. A rigorous analysis of the interactions between them implies that a synergy exists which, if properly it is understood that can be helpful to reduce the environmental impacts of the AEC industry. A BIM-based design model can contribute to sustainability through its three main dimensions which are environmental, economic and social. In this paper, by reviewing the existing literature on BIM and construction sustainability and using a matrix to analyze construction sustainability dimensions and BIM functionalities a number of interactions have been discussed. It can be concluded that despite there are many improvements in implementation of BIM in environmental and economic aspects of sustainability, its potential impact on social dimension has not been explicitly explored hence further studies need to be undertaken in this area.展开更多
A projection of the Canadian population shows that in 2024 one in five Canadians will be over 65 years old. This shift forces designers to consider the entire lifetime of occupants during the design of new buildings. ...A projection of the Canadian population shows that in 2024 one in five Canadians will be over 65 years old. This shift forces designers to consider the entire lifetime of occupants during the design of new buildings. Universal Design (UD), which is a design that accommodates all people to the greatest extent possible and aging in place design that is deeply rooted in the principles of UD, aim to house people irrespective of their age, ability, and chronic health conditions. Building Information Modeling (BIM) significantly helps advance the development of the Architecture, Engineering, and Construction (AEC) industry in a more collaborative and automated way. Integrating BIM and UD allows designers to incorporate UD standards easily and efficiently at the conceptual design stage of buildings by using the functionalities and capabilities of BIM tools. Therefore, this study presents the development of an automated computer model to facilitate the adoption of UD standards and processes. The novelty highlighted in this model resides in the creation of an automated method that employs a newly created plug-in and databases to assist designers to incorporate UD standards at the conceptual stage in a timely and cost-effective manner. Furthermore, the study introduces the methodology consisting of collecting, categorizing, and storing data from various universal design and accessible design guidelines in the developed databases and developing new plug-ins in BIM tool to link the developed databases in order to automate the process of retrieving necessary information and components to help designers and owners select optimal design alternatives based on their predefined criteria.展开更多
New development in urban planning, cityscape, real estate management and the like, calls for new demands for 3D city model. There are so many objects in 3D city model such as building, river, road, and so on. The buil...New development in urban planning, cityscape, real estate management and the like, calls for new demands for 3D city model. There are so many objects in 3D city model such as building, river, road, and so on. The building model is very important in 3D city model. In recent years,a lot of research work about visualization has been done. In our opinions,visualization is only a part of 313 city model, while interactive operation about buildings is rather important as well. In order to implement interactive operation (create , edit, query,etc. ), good data structure and model must be developed.展开更多
The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, buildi...The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, building information <span>modeling (BIM) and building energy modeling (BEM) are two important to</span>ols to make the transition to net-zero energy buildings (NZEB). So far, little attention has been devoted, in the literature, to discuss the connection between BIM, BEM, and Life-cycle assessment (LCA), which is the main topic of this article. A literature review of 157 journal articles and conference proceedings published between 1990 and 2020 is presented. This review outlines knowledge gaps concerning BIM, BEM, and environmental impact assessment. It suggests that defining the process with the right technology (at the right time) would result in a more integrated design process (IDP) and bridge current gaps. The most efficient way to improve process and technology is related to the competences of the architects, engineers and constructors (AEC). The review also indicates that the IDP in the early design phases (EDP) is in need of improvement for architects and engineers, where a better connection between design phases, specific levels of development (LOD) and BIM tools is needed. <span>Competences, process and technology are the three main themes addressed in the review. Their relation to design phases and LOD is discussed. The aim </span>is to propose possible solutions to the current hinders in BIM-to-BEM (BIM2BEM) and BIM-for-LCA (BIM4LCA) integration.展开更多
基金Financial support for this research was provided in part by the US Army Corps of Engineers through a subaward from the University of California,San Diego,USA。
文摘Computer vision-based inspection methods show promise for automating post-earthquake building inspections.These methods survey a building with unmanned aerial vehicles and automatically detect damage in the collected images.Nevertheless,assessing the damage′s impact on structural safety requires localizing damage to specific building components with known design and function.This paper proposes a BIM-based automated inspection framework to provide context for visual surveys.A deep learning-based semantic segmentation algorithm is trained to automatically identify damage in images.The BIM automatically associates any identified damage with specific building components.Then,components are classified into damage states consistent with component fragility models for integration with a structural analysis.To demonstrate the framework,methods are developed to photorealistically simulate severe structural damage in a synthetic computer graphics environment.A graphics model of a real building in Urbana,Illinois,is generated to test the framework;the model is integrated with a structural analysis to apply earthquake damage in a physically realistic manner.A simulated UAV survey is flown of the graphics model and the framework is applied.The method achieves high accuracy in assigning damage states to visible structural components.This assignment enables integration with a performance-based earthquake assessment to classify building safety.
文摘The growing demand for current and precise geographic information that pertains to urban areas has given rise to a significant interest in digital surface models that exhibit a high level of detail. Traditional methods for creating digital surface models are insufficient to reflect the details of earth’s features. These models only represent three-dimensional objects in a single texture and fail to offer a realistic depiction of the real world. Furthermore, the need for current and precise geographic information regarding urban areas has been increasing significantly. This study proposes a new technique to address this problem, which involves integrating remote sensing, Geographic Information Systems (GIS), and Architecture Environment software environments to generate a detailed three-dimensional model. The processing of this study starts with: 1) Downloading high-resolution satellite imagery; 2) Collecting ground truth datasets from fieldwork; 3) Imaging nose removing; 4) Generating a Two-dimensional Model to create a digital surface model in GIS using the extracted building outlines; 5) Converting the model into multi-patch layers to construct a 3D model for each object separately. The results show that the 3D model obtained through this method is highly detailed and effective for various applications, including environmental studies, urban development, expansion planning, and shape understanding tasks.
文摘The use of three-dimensional maps is more effective than two-dimensional maps in representing the Earth’s surface. However, the traditional methods used to create digital surface models are not efficient for capturing the details of Earth’s features. This is because they represent only three-dimensional objects in a single texture and do not provide a realistic representation of the real world. Additionally, there is a growing demand for up-to-date and accurate geo-information, particularly in urban areas. To address this challenge, a new technique is proposed in this study that involves integrating remote sensing, Geographic Information System, and Architecture Environment software to generate a highly-detailed three-dimensional model. The method described in this study includes several steps such as acquiring high-resolution satellite imagery, gathering ground truth data, performing radiometric and geometric corrections during image preprocessing, producing a 2D map of the region of interest, constructing a digital surface model by extending the building outlines, and transforming the model into multi-patch layers to create a 3D model for each object individually. The research findings indicate that the digital surface model obtained with comprehensive information is suitable for different purposes, such as environmental research, urban development and expansion planning, and shape recognition tasks.
基金supported by the National Natural Science Foundation of China(Nos.41230318,41074077)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130132110023)the Fundamental Research Funds for the Central Universities of China(No.201413004)
文摘In order to improve the efficiency of 3D near-surface velocity model building, we develop a layer-stripping method using seismic first-arrival times. The velocity model within a Common Mid-Point (CMP) gather is assumed to be stratified into thin layers, and the velocity of each layer var- ies linearly with depth. The thickness and velocity of the top layer are estimated using minimum-offset first-arrival data in a CMP gather. Then the top layer is stripped and the second layer becomes a new top layer. After removing the effect of the top layer from the former first-arrival data, the new first-arrival data are obtained and then used to estimate the parameters of the second layer. In this manner, the velocity model, being regarded as that at a CMP location, is built layer-by-layer from the top to the bottom. A 3D near-surface velocity model is then formed using the velocity models at all CMP locations. The tests on synthetic and observed seismic data show that the layer-stripping method can be used to build good near-surface velocity models for static correction, and its computation speed is approximately hundred times faster than that of grid tomography.
基金The project acknowledges that this work was financially supported by the Open Project of Key Laboratory of Ministry of Agriculture and Rural Affairs(KLTMCUAR2020-3).
文摘Composting is a suitable low-cost strategy to transform animal waste into a stabilized end product,and the airflow field in the pile affects the fermentation states.For piles in the aeration weak zone,anaerobic fermentation may happen as the lack of oxygen.While in practice,due to the extremely low speed and harsh condition,the airflow field was scarcely researched.This study adopted Computational Fluid Dynamics(CFD)to investigate the airflow field in the compost pile.A three-dimensional CFD model was built;the compost pile in this model was simplified as porous media;unstructured mesh was adopted to discretize the geometric model;standard k-εmodel and SIMPLE scheme were employed for numerical methods.The CFD model was validated with the field experiment in the cooling period.Then the model was applied to research the airflow field in the pile with increased pipe diameter.Results showed that it was feasible to investigate the airflow field in the pile with CFD.For boundary conditions in the CFD model,treating the compost pile as a homogeneous porous media is reasonable.The CFD model was successfully validated by the field measurement(the average relative difference between the simulated and measured air speed was within 10%).Airflow in the existing compost pile showed nonuniform distribution with stagnation and vortex zones;the turbulence intensities were 3.57 and 1.43 for the airflow in the pile and the reactor,respectively.When pipe diameter increased,the airflow distribution uniformity in the pile was improved significantly.With diameter raising to 0.04 m,the turbulence intensity decreased to 1.54 and 0.42 for the airflow in the pile and the reactor,respectively.The CFD model developed in this research can provide qualitative and quantitative analyses of the airflow field in compost piles,and can be a theoretical basis for the aeration system design.
基金supported by a grant(No.14DZ2292800,http://www.greengeo.net/)from“Technology Service Platform of Civil Engineering”of Science and Technology Commission of Shanghai Municipality.
文摘Underground pipeline networks constitute a major component of urban infrastructure,and thus,it is imperative to have an efficient mechanism to manage them.This study introduces a secondary development system to efficiently model underground pipeline networks,using the building information modeling(BIM)-based software Revit.The system comprises separate pipe point and tubulation models.Using a Revit application programming interface(API),the spatial position and attribute data of the pipe points are extracted from a pipeline database,and the corresponding tubulation data are extracted from a tubulation database.Using the Family class in Revit API,the cluster in the self-built library of pipe point is inserted into the spatial location and the attribute data is added;in the same way,all pipeline instances in the pipeline system are created.The extension and localization of the model accelerated the modeling speed.The system was then used in a real construction project.The expansion of the model database and rapid modeling made the application of BIM technology in three-dimensional visualization of underground pipeline networks more convenient.Furthermore,it has applications in pipeline engineering construction and management.
基金Supported by the National Nature Foundation of China (No.59975073)
文摘An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS.
文摘Energy consumption reduction efforts in the residential buildings sector represent socio-economical, technological and environmental preoccupations which justify advanced scientific research. These lead to use inverse models to describe thermal behavior and to evaluate the energy consumption of buildings. Their principal goal is to provide supporting evidence of enhanced energy performances and predictions. More specifically, research questions are related to building thermal modeling which is the most appropriate in a smart grid context. In this context, the models are reviewed according to three categories. The first category is based on physical and basic principle modeling (white-box). The second offers a much simpler structure which is the statistical models (black-box). The black-box is used for prediction of energy consumption and heating/ cooling demands. Finally, the third category is a hybrid method (grey-box), which uses both physical and statistical modeling techniques. In this paper, we propose a detailed review and simulation of the main thermal building models. Our comparison and simulation results demonstrate that the grey-box is the most effective model for management of buildings energy consumption.
文摘Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans. Researchers have made numerous efforts to accurately calculate emissions to reduce the life cycle carbon emissions of residential buildings. Nevertheless, there are still difficulties in quickly estimating carbon emissions in the design stage without specific data. To fill this gap, the study, based on Life Cycle Assessment (LCA) and Building Information Modeling (BIM), proposed a quick method for estimating Building’s Life Cycle Carbon Emissions (BLCCE). Taking a hospital building in Chuzhou City, Anhui Province, China as an example, it tested its possibility to estimate BLCCE. The results manifested that: 1) the BLCCE of the project is 40,083.56 tCO2-eq, and the carbon emissions per square meter per year are 119.91 kgCO2-eq/(m2·y);2) the stage of construction, operational and demolition account for 7.90%, 91.31%, and 0.79% of BLCCE, respectively;3) the annual carbon emissions per square meter of hospital are apparently higher than that of villa, residence, and office building, due to larger service population, longer daily operation time, and stricter patient comfort requirements. Considering the lack of BLCCE research in Chinese hospitals, this case study will provide a valuable reference for the estimated BLCCE of hospital building.
文摘Dengue community capacity (DCC) is important for developing a sustainable approach to over-coming the problem of dengue. The objectives were 1) to develop and 2) evaluate a dengue community capacity building model for the leader and non-leader group in three communities selected by purposive technique. A mixed method research design was used employing both qualitative and quantitative methods with qualitative studies conducted for community capacity building model: assessment, planning, implementation, and evaluation. DCC level was assessed by the Dengue Community Capacity Assessment Tool (DCCAT) including larval indices, and morbidity and mortality rate. To analyze the differences of the leader and non-leader’s DCC levels both pre and post-interventions in each model, the Mann-Whitney and Independent T-test were used and to analyze the difference of the DCC level among the three models (Ban Mon, Ban Nangpraya and Ban Kang), the Kruskal-Wallis Test, ANOVA, and ANCOVA were used. The findings showed that there were some differences among the three models in dengue community capacity building in terms model. The participants consisted of leader (n = 26, 24 and 28) and non-leader groups (n = 200, 215 and 176 respectively). The DCC levels of both leader and non-leader groups increased post-intervention in each model (p < 0.001) and in all three models, showing a statistically significant difference between pre and post-intervention (p < 0.001). Ban Kang model demonstrated the highest DCC levels of leader and non-leader groups, the lowest larval indices (HI, BI, and CI), and no dengue morbidity. In contrast, Ban Mon and Ban Nangpraya model showed low DCC level in both leader and non-leader groups, a high rate of larval indices and high dengue morbidity rate. However, there was no mortality rate in three areas. The conclusion indicates that the model with a high DCC level showed low risk on the dengue index both entomological and epidemiology index. The model of dengue community capacity building for dengue solution was sustainability not only needs to be maintained DCC levels but also increased dependent upon the contexts of each community.
基金Sponsored by the Experimental Teaching Reform and Laboratory Construction Project of University of Science and Technology Liaoning in 2015"Experimental Teaching Reform of Form Composition in Basis of Architectural Design"Project of the 13th Five-Year Plan for Education and Science of Liaoning Province in 2016(JG16DB222)
文摘To comply with the strategic goal of "mass entrepreneurship and innovation",universities and col eges adjusted the discipline cultivation objective to be cultivation of innovational and enterprising talents.Innovational and enterprising talents are inseparable from creative thinking,while the cultivation of creative thinking is the basis of cultivation of innovational and enterprising talents.This paper discussed cultivation of students' creative thinking through making building models in basic course of architectural design.Besides,it analyzed the relation between making of building models and creative thinking from divergent thinking,multi-directional thinking,element changing thinking,conversion thinking,and reverse thinking.It is expected to cultivate students' creative thinking through building models,to lay a solid foundation for architectural design courses,and to provide more architectural designers with more solid foundation and creative thinking.
文摘Building Information Modelling (BIM) is a technology and a process that has brought changes in the construction’s traditional procurement system. Kenya lacks contractual guidelines on implementation of BIM;this makes the adoption of BIM slow and difficult. Previous research has identified a gap in contractual relationships, roles and resulting risks. The objectives of this study were to investigate BIM adoption in Nairobi and to investigate the influence of BIM on Engineering Contract Management (ECM)</span><span style="font-family:Verdana;"> in Nairobi Kenya</span><span style="font-family:Verdana;">. The survey research was a descriptive study with 175 responsive questionnaires. Respondents comprised of Civil Engineers, Construction Project Managers, Architects, Quantity Surveyors, Contractors and Facility Managers. Data was collected through self-administered questionnaire and in-depth interview. Descriptive analytics, correlation and Exploratory factor analysis methods were used to analyse quantitative data. Qualitative data was analysed thematically. It emerged that adoption level was at 56.6% and shallow understanding of BIM capabilities remains to be a barrier to its adoption and implementation. It also emerged that BIM improves ECM;when time, cost, quality, collaboration and return on investment improve, ECM becomes easier. Latent factors found in BIM and ECM relationship were Legal Implications, awareness and knowledge, efficiency, versatility, mandate and leadership, and competitiveness. Further, the study found out that BIM influence on ECM demands for establishment of standards, guidelines, policy, legal framework, and regulations, which can be achieved by amending the public procurement act which dictates the operation of all the other standard forms of contract. Further research should be conducted to measure whether the understanding of BIM had positively improved.
文摘The location and nature of the moisture leakages are sometimes difficult to detect. Moreover, the relation between observed inside surface moisture patterns and where the moisture enters the construction is often not clear. The objective of this paper is to investigate inverse modeling techniques as a tool for the detection of moisture leakage locations in building constructions from inside surface moisture patterns. It is concluded that although the presented methodology is promising, more research is needed to confirm its usability.
基金Research Committee,University of Macao,China Under Grant No.RG077/07-08S/09R/YKV/FST
文摘One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.
文摘Global concerns toward environmental issues have induced growing demand for new approaches in the construction because of its considerable impact on the environment and use of natural resources. Through using construction sustainability tools, methods and techniques, a greener design can be applied during various building phases. In this connection, it is argued that the analytical and integrated models applied by Building Information Modelling (BIM) may also facilitate this process to be performed more efficiently. BIM and construction sustainability are quite different initiatives, but both have received much attention in recent years in the architecture, engineering and construction (AEC) industry. A rigorous analysis of the interactions between them implies that a synergy exists which, if properly it is understood that can be helpful to reduce the environmental impacts of the AEC industry. A BIM-based design model can contribute to sustainability through its three main dimensions which are environmental, economic and social. In this paper, by reviewing the existing literature on BIM and construction sustainability and using a matrix to analyze construction sustainability dimensions and BIM functionalities a number of interactions have been discussed. It can be concluded that despite there are many improvements in implementation of BIM in environmental and economic aspects of sustainability, its potential impact on social dimension has not been explicitly explored hence further studies need to be undertaken in this area.
文摘A projection of the Canadian population shows that in 2024 one in five Canadians will be over 65 years old. This shift forces designers to consider the entire lifetime of occupants during the design of new buildings. Universal Design (UD), which is a design that accommodates all people to the greatest extent possible and aging in place design that is deeply rooted in the principles of UD, aim to house people irrespective of their age, ability, and chronic health conditions. Building Information Modeling (BIM) significantly helps advance the development of the Architecture, Engineering, and Construction (AEC) industry in a more collaborative and automated way. Integrating BIM and UD allows designers to incorporate UD standards easily and efficiently at the conceptual design stage of buildings by using the functionalities and capabilities of BIM tools. Therefore, this study presents the development of an automated computer model to facilitate the adoption of UD standards and processes. The novelty highlighted in this model resides in the creation of an automated method that employs a newly created plug-in and databases to assist designers to incorporate UD standards at the conceptual stage in a timely and cost-effective manner. Furthermore, the study introduces the methodology consisting of collecting, categorizing, and storing data from various universal design and accessible design guidelines in the developed databases and developing new plug-ins in BIM tool to link the developed databases in order to automate the process of retrieving necessary information and components to help designers and owners select optimal design alternatives based on their predefined criteria.
基金Project supported by the National Natural Science Foundation of China(No.69833010)
文摘New development in urban planning, cityscape, real estate management and the like, calls for new demands for 3D city model. There are so many objects in 3D city model such as building, river, road, and so on. The building model is very important in 3D city model. In recent years,a lot of research work about visualization has been done. In our opinions,visualization is only a part of 313 city model, while interactive operation about buildings is rather important as well. In order to implement interactive operation (create , edit, query,etc. ), good data structure and model must be developed.
文摘The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, building information <span>modeling (BIM) and building energy modeling (BEM) are two important to</span>ols to make the transition to net-zero energy buildings (NZEB). So far, little attention has been devoted, in the literature, to discuss the connection between BIM, BEM, and Life-cycle assessment (LCA), which is the main topic of this article. A literature review of 157 journal articles and conference proceedings published between 1990 and 2020 is presented. This review outlines knowledge gaps concerning BIM, BEM, and environmental impact assessment. It suggests that defining the process with the right technology (at the right time) would result in a more integrated design process (IDP) and bridge current gaps. The most efficient way to improve process and technology is related to the competences of the architects, engineers and constructors (AEC). The review also indicates that the IDP in the early design phases (EDP) is in need of improvement for architects and engineers, where a better connection between design phases, specific levels of development (LOD) and BIM tools is needed. <span>Competences, process and technology are the three main themes addressed in the review. Their relation to design phases and LOD is discussed. The aim </span>is to propose possible solutions to the current hinders in BIM-to-BEM (BIM2BEM) and BIM-for-LCA (BIM4LCA) integration.