An efficient multi-purpose construction crawler training simulator is developed based on windows platform using digital signal processing,multimedia,sensing,simulation modeling and real-time visualization simulation t...An efficient multi-purpose construction crawler training simulator is developed based on windows platform using digital signal processing,multimedia,sensing,simulation modeling and real-time visualization simulation technologies. The simulator architecture and each part are discussed in this paper. The module designs for data acquisition,dynamic modeling and visual,sound and assess simulation are focused. The system has been put into practice and the satisfactory results are got.展开更多
This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be u...This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be used to describe the status of entrepreneurial network construction. We use the Lagrange multiplier procedure to deal with our problem, but it is too complicated to get the exact solu-tion. So we introduce the homotopy method to deal with it. We give the flow chart to describe how to get the solution via the homotopy method. We also illustrate our model in both the classical procedure and the homotopy method. Comparing the two methods, we can see that the homotopy method is more exact and efficient.展开更多
As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence...As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence time distributions of the lab scale subsurface flow constructed wetland.Considering the presence of trailing and multiple peaks of the tracer breakthrough curve,the multi flow dispersion model(MFDM)was used to fit the experimental tracer breakthrough curves.According to the residual sum of squares and comparison between the experimental values and simulated values of the tracer concentration,MFDM could fit the residence time distribution(RTD)curve satisfactorily,the results of which also reflected the layered structure of wetland cells,thus to give reference for application of MFDM to the same kind of subsurface flow constructed wetlands.展开更多
As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stag...As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stages and calculated the life-cycle CO_2 emissions of the construction sector in 30 Chinese provincial jurisdictions to understand the disparity among them.Results show that building materials production was the key stage for carbon reduction in the construction sector,followed by the building operation stage.External variables,e.g.,economic growth,industrial structure,urbanization,price fluctuation,and marketization,were significantly correlated with the emission intensity of the construction sector.Specifically,economic growth exhibited an inverted U-shaped relation with CO_2 emissions per capita and per area during the period examined.Secondary industry and land urbanization were negatively correlated with CO_2 emission intensity indicators from the construction sector,whereas tertiary industry and urbanization were positively correlated.Price indices and marketization had negative effects on CO_2 emission intensity.The policy implications of our findings are that cleaner technologies should be encouraged for cement providers,and green purchasing rules for the construction sector should also be established.Pricing tools(e.g.,resource taxes)could help to adjust the demand for raw materials and energy.展开更多
With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference...With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference due to crossover working procedures, tight time schedule, high quality of reinforced concrete and showcase appearance requirements, hidden troubles affecting construction safety. With above-mentioned factors in consideration, a single-side-separated sliding formwork technology advanced from past sliding formwork experiences has been developed and applied successfully. This new technology is beneficial in quick and safe operation, capable to assure best quality and appearance of shiplock concrete works, and has filled up the gap in terms of construction sliding formwork in our country.展开更多
Selecting a contractor for construction project is a difficult decision to be taken by a client because it may lead to construction delivery problems or successful delivery of the project. This study, therefore, inves...Selecting a contractor for construction project is a difficult decision to be taken by a client because it may lead to construction delivery problems or successful delivery of the project. This study, therefore, investigated the contractor selection criteria in the Ghanaian construction industry, considering the benefits and challenges. A quantitative research method was adopted in this study through the use of a questionnaire. The target population for the study consisted of registered contractors and consultants in the Ashanti and Brong-Ahafo regions of Ghana. It was found that though the construction professionals are well vested with the prequalification selection criteria that are being used within the Ghanaian construction industry, they were not familiar with multi-criterial section methods. It was also found that the benefits of the contractor selection criteria include: enabling the client to select contractors who are performers for the project, saving the project owner a lot of time, minimizing the possibility of contractor default, and facilitating the achievement of project success and the objectives within the scheduled time. Furthermore, excessive cost and time overrun, poor quality standard, imprecise assessments due to lack of information, criteria being very complex and difficult to apply in practice, among others were identified as the challenges to the contractor selection criteria in Ghanaian construction industry. The study recommends for further studies to determine the impact of the identified challenges on construction projects, and ways to minimize the challenges.展开更多
Urbanization and living comfort have revolutionized the construction industry. Many techniques and strategies have been used to improve the overall efficiency of construction and to reduce waste during and after the c...Urbanization and living comfort have revolutionized the construction industry. Many techniques and strategies have been used to improve the overall efficiency of construction and to reduce waste during and after the construction activity;some are cost effective and some not. Sustainable construction strategies have addressed these issues by proposing relatively more cost effective and environment-saving solutions. One strategy is to select sustainable construction materials at the building design stage. This article involved a questionnaire survey to collect data about local technical stakeholders’ (architects, designers, engineers, estimators, and managers) awareness of environmental sustainability and current practices for selecting construction materials. A sustainability index (SI) was developed using SPSS (Statistical Package for the Social Sciences) for the complex statistical analysis. These data were used to develop a decision support system (DSS) using the multi-criteria decision making (MCDM) technique, the TOPSIS. The support system was validated by applying it to sustainable roof products in a pilot case study—these materials are frequently used in local markets for residential construction in West Australia. So the main objective was to get insight to local market trends and features involved in construction materials selection. Data analysis was carried out to develop a decision support system to help technical stakeholders in construction materials selection process.展开更多
Based on methods for evaluating the overall planning and implementation of land use of domestic scholars, a comprehensive and highly-operable index system and evaluating method for land use planning multi-type impleme...Based on methods for evaluating the overall planning and implementation of land use of domestic scholars, a comprehensive and highly-operable index system and evaluating method for land use planning multi-type implementation has been established through selecting multi-type evaluating indicators and applied to the last-round overall planning of land use in Xinjiang Production and Construction Corps Agriculture-seven Division. The obtained comprehensive score was 86.40, indicating that land use overall planning has been excellently coordinated with land, society, economy as well as ecology and has exerted outstanding effect with the rank as "good". The evaluation results are in accordance with actual conditions, which displays that the established multi-type implementation evaluating system of land use overall planning is reasonable with scientific evaluating methods and can be the reference for evaluation of land use overall planning in other regiments and companies of Xinjiang Production and Construction Corps.展开更多
文摘An efficient multi-purpose construction crawler training simulator is developed based on windows platform using digital signal processing,multimedia,sensing,simulation modeling and real-time visualization simulation technologies. The simulator architecture and each part are discussed in this paper. The module designs for data acquisition,dynamic modeling and visual,sound and assess simulation are focused. The system has been put into practice and the satisfactory results are got.
文摘This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be used to describe the status of entrepreneurial network construction. We use the Lagrange multiplier procedure to deal with our problem, but it is too complicated to get the exact solu-tion. So we introduce the homotopy method to deal with it. We give the flow chart to describe how to get the solution via the homotopy method. We also illustrate our model in both the classical procedure and the homotopy method. Comparing the two methods, we can see that the homotopy method is more exact and efficient.
基金Under the auspices of the Creative Group Foundation of the National Natural Science Foundation of China(50721006)the National Basic Research Program of China(2006CB403402-3)+1 种基金the National Water Resource and Environment Special Item(2008ZX07207-006-04)the Natural Science Foundation of Shanghai(10ZR1400300)
文摘As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence time distributions of the lab scale subsurface flow constructed wetland.Considering the presence of trailing and multiple peaks of the tracer breakthrough curve,the multi flow dispersion model(MFDM)was used to fit the experimental tracer breakthrough curves.According to the residual sum of squares and comparison between the experimental values and simulated values of the tracer concentration,MFDM could fit the residence time distribution(RTD)curve satisfactorily,the results of which also reflected the layered structure of wetland cells,thus to give reference for application of MFDM to the same kind of subsurface flow constructed wetlands.
基金Under the auspices of the National Natural Science Foundation of China(No.41101567)
文摘As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stages and calculated the life-cycle CO_2 emissions of the construction sector in 30 Chinese provincial jurisdictions to understand the disparity among them.Results show that building materials production was the key stage for carbon reduction in the construction sector,followed by the building operation stage.External variables,e.g.,economic growth,industrial structure,urbanization,price fluctuation,and marketization,were significantly correlated with the emission intensity of the construction sector.Specifically,economic growth exhibited an inverted U-shaped relation with CO_2 emissions per capita and per area during the period examined.Secondary industry and land urbanization were negatively correlated with CO_2 emission intensity indicators from the construction sector,whereas tertiary industry and urbanization were positively correlated.Price indices and marketization had negative effects on CO_2 emission intensity.The policy implications of our findings are that cleaner technologies should be encouraged for cement providers,and green purchasing rules for the construction sector should also be established.Pricing tools(e.g.,resource taxes)could help to adjust the demand for raw materials and energy.
文摘With high rock slope in shiplock area, thin reinforced concrete lining walls are constructed for the shiplock system. The construction technology involves much complicated structures in formwork, frequent interference due to crossover working procedures, tight time schedule, high quality of reinforced concrete and showcase appearance requirements, hidden troubles affecting construction safety. With above-mentioned factors in consideration, a single-side-separated sliding formwork technology advanced from past sliding formwork experiences has been developed and applied successfully. This new technology is beneficial in quick and safe operation, capable to assure best quality and appearance of shiplock concrete works, and has filled up the gap in terms of construction sliding formwork in our country.
文摘Selecting a contractor for construction project is a difficult decision to be taken by a client because it may lead to construction delivery problems or successful delivery of the project. This study, therefore, investigated the contractor selection criteria in the Ghanaian construction industry, considering the benefits and challenges. A quantitative research method was adopted in this study through the use of a questionnaire. The target population for the study consisted of registered contractors and consultants in the Ashanti and Brong-Ahafo regions of Ghana. It was found that though the construction professionals are well vested with the prequalification selection criteria that are being used within the Ghanaian construction industry, they were not familiar with multi-criterial section methods. It was also found that the benefits of the contractor selection criteria include: enabling the client to select contractors who are performers for the project, saving the project owner a lot of time, minimizing the possibility of contractor default, and facilitating the achievement of project success and the objectives within the scheduled time. Furthermore, excessive cost and time overrun, poor quality standard, imprecise assessments due to lack of information, criteria being very complex and difficult to apply in practice, among others were identified as the challenges to the contractor selection criteria in Ghanaian construction industry. The study recommends for further studies to determine the impact of the identified challenges on construction projects, and ways to minimize the challenges.
文摘Urbanization and living comfort have revolutionized the construction industry. Many techniques and strategies have been used to improve the overall efficiency of construction and to reduce waste during and after the construction activity;some are cost effective and some not. Sustainable construction strategies have addressed these issues by proposing relatively more cost effective and environment-saving solutions. One strategy is to select sustainable construction materials at the building design stage. This article involved a questionnaire survey to collect data about local technical stakeholders’ (architects, designers, engineers, estimators, and managers) awareness of environmental sustainability and current practices for selecting construction materials. A sustainability index (SI) was developed using SPSS (Statistical Package for the Social Sciences) for the complex statistical analysis. These data were used to develop a decision support system (DSS) using the multi-criteria decision making (MCDM) technique, the TOPSIS. The support system was validated by applying it to sustainable roof products in a pilot case study—these materials are frequently used in local markets for residential construction in West Australia. So the main objective was to get insight to local market trends and features involved in construction materials selection. Data analysis was carried out to develop a decision support system to help technical stakeholders in construction materials selection process.
文摘Based on methods for evaluating the overall planning and implementation of land use of domestic scholars, a comprehensive and highly-operable index system and evaluating method for land use planning multi-type implementation has been established through selecting multi-type evaluating indicators and applied to the last-round overall planning of land use in Xinjiang Production and Construction Corps Agriculture-seven Division. The obtained comprehensive score was 86.40, indicating that land use overall planning has been excellently coordinated with land, society, economy as well as ecology and has exerted outstanding effect with the rank as "good". The evaluation results are in accordance with actual conditions, which displays that the established multi-type implementation evaluating system of land use overall planning is reasonable with scientific evaluating methods and can be the reference for evaluation of land use overall planning in other regiments and companies of Xinjiang Production and Construction Corps.
