It is difficult to analyze the inter-relationship for the construction layout of a reservoir project scientifically and intuitively.According to the characteristics of broad field and huge information,the modeling met...It is difficult to analyze the inter-relationship for the construction layout of a reservoir project scientifically and intuitively.According to the characteristics of broad field and huge information,the modeling methods of digital terrain and solid model as well as the techniques of texture mapping and scene navigation are adopted.The simulation system is developed by C program language,which includes the functions of the interactive navigation of 3D scene,the visual inquiry of project digital model information,the storage and management of project information.A certain reservoir is taken as a case.The 3D visual analysis for the construction layout and engineering information are obtained.The proposed system is of great advantages in dealing with large amount of information and the method provides a theoretical basis and technical support for the construction layout of a reservoir project.展开更多
Projects delay and cost overrun have become general facts in the construction industry. Project cost risk analysis considers the different costs associated with a project and focuses on the uncertainties and risks tha...Projects delay and cost overrun have become general facts in the construction industry. Project cost risk analysis considers the different costs associated with a project and focuses on the uncertainties and risks that may affect these costs. An implementation of PRM （project risk management） process on regional construction project has been carried out to maximize the likelihood of project meeting its objectives within its constraints. Qualitative and quantitative risk analyses have been carried out. The qualitative analysis is presented in a table that shows top ranked risks in Libyan construction projects based on probability-impact grid technique. In quantitative risk analyses, Mont Carlo simulation technique has been conducted to quantify and evaluate the overall level of risk exposure associated with the project completion cost. A project simulation uses a model that translates cost uncertainties into their potential impact on project objectives. A frequency curve model that represents simulation results of project completion costs has been constructed. The frequency curve model shows all possible outcomes of expected project cost at different probabilities. Project manager or decision maker can select the appropriate project budget. If a probability of 0.95 confident project budget is selected that means cost overrun risk can be minimized to a probability of 0.05. It is very helpful for project manager to take decisions based on information that shows project completion cost and its associated probability rather than usin single information of estimated cost.展开更多
Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of ...Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of agreements and compromises between the interests of the government, common interests, and the motives and interests of individual owners and prospective investors. Research that deals with any portion of cultural heritages always carried out very precisely, but there is still no precise knowledge of how to define a system and draw up a model that accurately represents a cultural heritage. In the existing literature on this topic, the authors have written about the different views of how to explain the construction project as a system. While many authors focus on ＂sub-phases＂ directly connected to the building of an object, the process involved in the construction phase often neglects the phases required before beginning work, which culminates in a logical sequence in the process of preparing a project. Irregularities or deficiencies which occur during the preparation process of a project often directly impact the construction itself. What the scope of this impact depends on the approach of the contractual organization, the organization of construction companies and on co-operation between the customer （or architects） and the contractors. Unlike the projects for newly built objects, the conservation projects of cultural heritage are not only more demanding because of lack of knowledge of the building materials, construction, foundation and interaction of the mentioned individual parts into a unit called a building. The authors analyzed the structural aspects of building conservation which were suggested by Beckmaun and Bowles and another methodology, which was developed as part of the 5th framework program for the purpose of providing a comprehensive and interdisciplinary treatment of the revitalization of a historical city. The authors found that both methodologies do not include modern IT tools and methods. By analyzing and monitoring the restoration of historic buildings in Slovenia, specifically in the city of Maribor （including all documentation, interviews and direct views） the authors found that the project was regarded as a collection of individual projects rather than a unified whole （a system）. The authors have demonstrated the consequences of structuring a historic building restoration project in a non-systemic way. This type of project can be classified as a non-sustainable renovation. In this article, at first the authors will try to clarify what types of systems and subsystems are considered in renovating historic buildings. The authors show when and why a system becomes stochastic （a probability） and in the end what would be needed to successfully re-establish it back to a determined system. By analyzing the work and reconstruction of old buildings in Maribor, the authors found that it would be necessary to give a new framework with IT tools for the preparation of a historic building restoration project.展开更多
The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing...The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.展开更多
基金Supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.51021004)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC29200)National Key Technology R and D Program in the 12th Five-Year Plan of China(No.2011BAB10B06)
文摘It is difficult to analyze the inter-relationship for the construction layout of a reservoir project scientifically and intuitively.According to the characteristics of broad field and huge information,the modeling methods of digital terrain and solid model as well as the techniques of texture mapping and scene navigation are adopted.The simulation system is developed by C program language,which includes the functions of the interactive navigation of 3D scene,the visual inquiry of project digital model information,the storage and management of project information.A certain reservoir is taken as a case.The 3D visual analysis for the construction layout and engineering information are obtained.The proposed system is of great advantages in dealing with large amount of information and the method provides a theoretical basis and technical support for the construction layout of a reservoir project.
文摘Projects delay and cost overrun have become general facts in the construction industry. Project cost risk analysis considers the different costs associated with a project and focuses on the uncertainties and risks that may affect these costs. An implementation of PRM （project risk management） process on regional construction project has been carried out to maximize the likelihood of project meeting its objectives within its constraints. Qualitative and quantitative risk analyses have been carried out. The qualitative analysis is presented in a table that shows top ranked risks in Libyan construction projects based on probability-impact grid technique. In quantitative risk analyses, Mont Carlo simulation technique has been conducted to quantify and evaluate the overall level of risk exposure associated with the project completion cost. A project simulation uses a model that translates cost uncertainties into their potential impact on project objectives. A frequency curve model that represents simulation results of project completion costs has been constructed. The frequency curve model shows all possible outcomes of expected project cost at different probabilities. Project manager or decision maker can select the appropriate project budget. If a probability of 0.95 confident project budget is selected that means cost overrun risk can be minimized to a probability of 0.05. It is very helpful for project manager to take decisions based on information that shows project completion cost and its associated probability rather than usin single information of estimated cost.
文摘Approaches to building renovation require high professional levels, interdisciplinary elements, team work and time to study and do research on the buildings. The process of renovating historic buildings is made up of agreements and compromises between the interests of the government, common interests, and the motives and interests of individual owners and prospective investors. Research that deals with any portion of cultural heritages always carried out very precisely, but there is still no precise knowledge of how to define a system and draw up a model that accurately represents a cultural heritage. In the existing literature on this topic, the authors have written about the different views of how to explain the construction project as a system. While many authors focus on ＂sub-phases＂ directly connected to the building of an object, the process involved in the construction phase often neglects the phases required before beginning work, which culminates in a logical sequence in the process of preparing a project. Irregularities or deficiencies which occur during the preparation process of a project often directly impact the construction itself. What the scope of this impact depends on the approach of the contractual organization, the organization of construction companies and on co-operation between the customer （or architects） and the contractors. Unlike the projects for newly built objects, the conservation projects of cultural heritage are not only more demanding because of lack of knowledge of the building materials, construction, foundation and interaction of the mentioned individual parts into a unit called a building. The authors analyzed the structural aspects of building conservation which were suggested by Beckmaun and Bowles and another methodology, which was developed as part of the 5th framework program for the purpose of providing a comprehensive and interdisciplinary treatment of the revitalization of a historical city. The authors found that both methodologies do not include modern IT tools and methods. By analyzing and monitoring the restoration of historic buildings in Slovenia, specifically in the city of Maribor （including all documentation, interviews and direct views） the authors found that the project was regarded as a collection of individual projects rather than a unified whole （a system）. The authors have demonstrated the consequences of structuring a historic building restoration project in a non-systemic way. This type of project can be classified as a non-sustainable renovation. In this article, at first the authors will try to clarify what types of systems and subsystems are considered in renovating historic buildings. The authors show when and why a system becomes stochastic （a probability） and in the end what would be needed to successfully re-establish it back to a determined system. By analyzing the work and reconstruction of old buildings in Maribor, the authors found that it would be necessary to give a new framework with IT tools for the preparation of a historic building restoration project.
基金supported by the National Science and Technology Plan(Grant No.2013BAB06B01)the Graduate Student Scientific Research Innovation Projects of Regular Institutions of Jiangsu Province(Grant Nos.CXZZ11_0439&CXZZ13_0236)
文摘The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.
