Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-f...Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-fuel based car-oriented solutions. The paper investigates a range of case studies where “tram-based boulevards” have been planned or implemented to provide such opportunities. The case studies share a common broader policy objective: to transform the car-oriented or car-saturated areas to an intensified urban template based on a critical presence of dedicated mid-tier transit infrastructure and active transport. “Trams”, or mid-tier, mid-capacity transit when combined with Transit oriented development (TOD) along whole corridors can provide transformative pathways towards zero-carbon outcomes as well as multiple, strong urban benefits. However, many successful or instructive examples of this practice from non-English speaking countries, particularly in Europe, are underdocumented in the international literature. The paper addresses this gap by investigating opportunities and challenges evident in a range of European case studies. These are explored for insight towards policy learning particularly in New World cities seeking to transform into a zero-carbon and more transit-oriented template: How can decision-makers avoid repeating the identified pitfalls, and instead focus on emulating the successful approaches and outcomes? We conclude the need for recognition of the inherent synergies between transport and land use settings in any endeavour, and their translation into policy priorities in both fields of planning. We also conclude the importance of decision makers proactively identifying and critically appraising specific opportunities for change, concerning funding, technology, public opinion, stakeholder alliances or market dynamics, and capitalising on them at suitable moments in time.展开更多
Recently,reliability-based design is a universal method to quantify negative influence of uncertainty in geotechnical engineering.However,for deep foundation pit,evaluating the system safety of retaining structures an...Recently,reliability-based design is a universal method to quantify negative influence of uncertainty in geotechnical engineering.However,for deep foundation pit,evaluating the system safety of retaining structures and finding cost-effective design points are main challenges.To address this,this study proposes a novel system reliability-based robust design method for retaining system of deep foundation pit and illustrated this method via a simplified case history in Suzhou,China.The proposed method included two parts:system reliability model and robust design method.Back Propagation Neural Network(BPNN)is used to fit limit state functions and conduct efficient reliability analysis.The common source random variable(CSRV)model are used to evaluate correlation between failure modes and determine the system reliability.Furthermore,based on the system reliability model,a robust design method is developed.This method aims to find cost-effective design points.To solve this problem,the third generation non-dominated genetic algorithm(NSGA-III)is adopted.The efficiency and accuracy of whole computations are improved by involving BPNN models and NSGA-III algorithm.The proposed method has a good performance in locating the balanced design point between safety and construction cost.Moreover,the proposed method can provide design points with reasonable stiffness distribution.展开更多
Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced relia...Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced reliability-based robust geotechnical design method,which can consider multiple failures and uncertainty of statistical information.A universal design sample was conducted to verify the necessity of considering the uncertainty of statistical information.Ultimate limit state and serviceability limit state of braced excavations were defined,and point estimating method was used to evaluate the standard deviation of failure probabilities.Two-objective and three-objective optimization models were developed to illustrate the application of proposed methods in detail.In addition,the performance of optimization algorithms and further application of multiple-objective models were discussed.The results from this study indicate that the proposed method has a good performance in determining the optimal design with reasonable robustness and cost.New algorithms have higher efficiency in solving nonlinear and multiple-objective optimization problems than the 2nd Non-dominated sorting genetic algo-rithm.This study can guide the design of retaining systems of braced excavations in clay.展开更多
Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and a...Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and an effective NER method can provide a solid foundation for downstream applications to improve construction management efficiency.This study presents a NER method for Chinese construction documents based on conditional random field(CRF),including a corpus design pipeline and a CRF model.The corpus design pipeline identifies typical NER tasks in construction management,enables word-based tokenization,and controls the annotation consistency with a newly designed annotating specification.The CRF model engineers nine transformation features and seven classes of state features,covering the impacts of word position,part-of-speech(POS),and word/character states within the context.The F1-measure on a labeled construction data set is 87.9%.Furthermore,as more domain knowledge features are infused,the marginal performance improvement of including POS information will decrease,leading to a promising research direction of POS customization to improve NLP performance with limited data.展开更多
文摘Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-fuel based car-oriented solutions. The paper investigates a range of case studies where “tram-based boulevards” have been planned or implemented to provide such opportunities. The case studies share a common broader policy objective: to transform the car-oriented or car-saturated areas to an intensified urban template based on a critical presence of dedicated mid-tier transit infrastructure and active transport. “Trams”, or mid-tier, mid-capacity transit when combined with Transit oriented development (TOD) along whole corridors can provide transformative pathways towards zero-carbon outcomes as well as multiple, strong urban benefits. However, many successful or instructive examples of this practice from non-English speaking countries, particularly in Europe, are underdocumented in the international literature. The paper addresses this gap by investigating opportunities and challenges evident in a range of European case studies. These are explored for insight towards policy learning particularly in New World cities seeking to transform into a zero-carbon and more transit-oriented template: How can decision-makers avoid repeating the identified pitfalls, and instead focus on emulating the successful approaches and outcomes? We conclude the need for recognition of the inherent synergies between transport and land use settings in any endeavour, and their translation into policy priorities in both fields of planning. We also conclude the importance of decision makers proactively identifying and critically appraising specific opportunities for change, concerning funding, technology, public opinion, stakeholder alliances or market dynamics, and capitalising on them at suitable moments in time.
基金The authors are grateful to the financial support from National Natural Science Foundation of China(No.52078086)Postdoctoral innovative talents support program,Chongqing(Grant No.CQBX2021022)Financial support from China Southwest Geotechnical Investigation&Design Institute Co.,Ltd(C2021-0264).
文摘Recently,reliability-based design is a universal method to quantify negative influence of uncertainty in geotechnical engineering.However,for deep foundation pit,evaluating the system safety of retaining structures and finding cost-effective design points are main challenges.To address this,this study proposes a novel system reliability-based robust design method for retaining system of deep foundation pit and illustrated this method via a simplified case history in Suzhou,China.The proposed method included two parts:system reliability model and robust design method.Back Propagation Neural Network(BPNN)is used to fit limit state functions and conduct efficient reliability analysis.The common source random variable(CSRV)model are used to evaluate correlation between failure modes and determine the system reliability.Furthermore,based on the system reliability model,a robust design method is developed.This method aims to find cost-effective design points.To solve this problem,the third generation non-dominated genetic algorithm(NSGA-III)is adopted.The efficiency and accuracy of whole computations are improved by involving BPNN models and NSGA-III algorithm.The proposed method has a good performance in locating the balanced design point between safety and construction cost.Moreover,the proposed method can provide design points with reasonable stiffness distribution.
基金supported by the National Natural Science Foundation of China(Grant No.52078086)Program of Distinguished Young Scholars,Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyj-jq0087).
文摘Reliability design of braced excavation is still a challenge for geotechnical community.Optimization design is a normal method to control the safety and cost of braced excavations.This study presents an advanced reliability-based robust geotechnical design method,which can consider multiple failures and uncertainty of statistical information.A universal design sample was conducted to verify the necessity of considering the uncertainty of statistical information.Ultimate limit state and serviceability limit state of braced excavations were defined,and point estimating method was used to evaluate the standard deviation of failure probabilities.Two-objective and three-objective optimization models were developed to illustrate the application of proposed methods in detail.In addition,the performance of optimization algorithms and further application of multiple-objective models were discussed.The results from this study indicate that the proposed method has a good performance in determining the optimal design with reasonable robustness and cost.New algorithms have higher efficiency in solving nonlinear and multiple-objective optimization problems than the 2nd Non-dominated sorting genetic algo-rithm.This study can guide the design of retaining systems of braced excavations in clay.
基金This work is supported by the National Natural Science Foundation of China(Grant No.71971196).
文摘Named entity recognition(NER)is essential in many natural language processing(NLP)tasks such as information extraction and document classification.A construction document usually contains critical named entities,and an effective NER method can provide a solid foundation for downstream applications to improve construction management efficiency.This study presents a NER method for Chinese construction documents based on conditional random field(CRF),including a corpus design pipeline and a CRF model.The corpus design pipeline identifies typical NER tasks in construction management,enables word-based tokenization,and controls the annotation consistency with a newly designed annotating specification.The CRF model engineers nine transformation features and seven classes of state features,covering the impacts of word position,part-of-speech(POS),and word/character states within the context.The F1-measure on a labeled construction data set is 87.9%.Furthermore,as more domain knowledge features are infused,the marginal performance improvement of including POS information will decrease,leading to a promising research direction of POS customization to improve NLP performance with limited data.
