ln order to improve the level of investment promotion and redouble effortsto enhance services,on February l9th,the 2025 Action Plan for StabilizingForeign lnvestment was released,proposing 20 measures in four aspects....ln order to improve the level of investment promotion and redouble effortsto enhance services,on February l9th,the 2025 Action Plan for StabilizingForeign lnvestment was released,proposing 20 measures in four aspects.Cur-rently,with increasing uncertainties in the external environment,China facesmultple difficulties and challenges in attracting foreign investment.展开更多
The development of a multiple level underground mine is a complex task in which geology,engineering,ground control,and unit operations are integrated into a single mine design.The components are interdependent and mus...The development of a multiple level underground mine is a complex task in which geology,engineering,ground control,and unit operations are integrated into a single mine design.The components are interdependent and must function cohesively to ensure a profitable underground mining operation.To optimize reserve recovery,mine planning should begin from the lowest level and progress up.This limits any misjudgments or oversights of a given level affecting the underlying levels and ensures the ability to maximize recovery from each level.Mine planning should start with the exploration and characterization of the geologic setting.Once the reserve geology and quality is well understood,then mine planning can begin with respect to the following:(1)orientation of mine works with respect to horizontal stress;(2)access to the reserve;(3)determination of opening widths;(4)selection of back,floor horizons and pillar centers;(5)selection of development and secondary mining heights;(6)appropriate inter-burden thicknesses;and(7)examining the stability of the multiple level mine through numerical modeling.The multiple level mine design process and decisions are presented through a case history example.The theme is that there is one opportunity to"get it right"and many chances to overlook a small aspect within the design that will plague the mine throughout all levels and through the entirety of its operating life.展开更多
An increasing number of drivers are relying on digital map navigation systems in vehicles or mobile phones to select optimal driving routes in order to save time and improve safety. In the near future, digital map nav...An increasing number of drivers are relying on digital map navigation systems in vehicles or mobile phones to select optimal driving routes in order to save time and improve safety. In the near future, digital map navigation systems are expected to play more important roles in transportation systems. In order to extend current navigation systems to more applications, two fundamental problems must be resolved: the lane-level map model and lane-level route planning. This study proposes solutions to both problems. The current limitation of the lane-level map model is not its accuracy but its flexibility;this study proposes a novel seven-layer map structure, called as Tsinghua map model, which is able to support autonomous driving in a flexible and efficient way. For lane-level route planning, we propose a hierarchical route-searching algorithm to accelerate the planning process, even in the presence of complicated lane networks. In addition, we model the travel costs allocated for lane-level road networks by analyzing vehicle maneuvers in traversing lanes, changing lanes, and turning at intersections. Tests were performed on both a grid network and a real lane-level road network to demonstrate the validity and efficiency of the proposed algorithm.展开更多
This paper presents an adaptive path planner for unmanned aerial vehicles （UAVs） to adapt a real-time path search procedure to variations and fluctuations of UAVs’ relevant performances, with respect to sensory cap...This paper presents an adaptive path planner for unmanned aerial vehicles （UAVs） to adapt a real-time path search procedure to variations and fluctuations of UAVs’ relevant performances, with respect to sensory capability, maneuverability, and flight velocity limit. On the basis of a novel adaptability-involved problem statement, bi-level programming （BLP） and variable planning step techniques are introduced to model the necessary path planning components and then an adaptive path planner is developed for the purpose of adaptation and optimization. Additionally, both probabilistic-risk-based obstacle avoidance and performance limits are described as path search constraints to guarantee path safety and navigability. A discrete-search-based path planning solution, embedded with four optimization strategies, is especially designed for the planner to efficiently generate optimal flight paths in complex operational spaces, within which different surface-to-air missiles （SAMs） are deployed. Simulation results in challenging and stochastic scenarios firstly demonstrate the effectiveness and efficiency of the proposed planner, and then verify its great adaptability and relative stability when planning optimal paths for a UAV with changing or fluctuating performances.展开更多
Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability ...Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability and enhance long-term resilience of these regions.This study explored a framework for climate change vulnerability assessment in the new urban planning process in Jangwani Ward,Tanzania.Specifically,taking flood as an example,this study highlighted the steps and methods for climate change vulnerability assessment in the new urban planning process.In the study area,95 households were selected and interviewed through purposeful sampling.Additionally,10 respondents(4 females and 6 males)were interviewed for Focus Group Discussion(FGD),and 3 respondents(1 female and 2 males)were selected for Key Informant Interviews(KII)at the Ministry of Lands,Housing and Human Settlements Development.This study indicated that climate change vulnerability assessment framework involves the assessment of climatic hazards,risk elements,and adaptive capacity,and the determination of vulnerability levels.The average hazard risk rating of flood was 2.3.Socioeconomic and livelihood activities and physical infrastructures both had the average risk element rating of 3.0,and ecosystems had the average risk element rating of 2.9.Adaptive capacity ratings of knowledge,technology,economy or finance,and institution were 1.6,1.9,1.4,and 2.2,respectively.The vulnerability levels of socioeconomic and livelihood activities and physical infrastructure were very high(4.0).Ecosystems had a high vulnerability level(3.8)to flood.The very high vulnerability level of socioeconomic and livelihood activities was driven by high exposure and sensitivity to risk elements and low adaptive capacity.The study recommends adoption of the new urban planning process including preparation,planning,implementation,and monitoring-evaluation-review phases that integrates climate change vulnerability assessment in all phases.展开更多
A smart city provides a new idea and model for urban construction, management, and development. This article proposes the concepts and methodology for top-level design of smart cities based on the ＂ Integration of Fo...A smart city provides a new idea and model for urban construction, management, and development. This article proposes the concepts and methodology for top-level design of smart cities based on the ＂ Integration of Four Plans ＂, and the planning process and systems for implementing the top-level design of smart cities. This article discusses, from the perspective of a city, how to optimize resource allocation, coordinate the development of urban economy, society, resources, environment, and people＇s livelihood, and map out the blueprints for healthy and sustainable development of a smart city.展开更多
文摘ln order to improve the level of investment promotion and redouble effortsto enhance services,on February l9th,the 2025 Action Plan for StabilizingForeign lnvestment was released,proposing 20 measures in four aspects.Cur-rently,with increasing uncertainties in the external environment,China facesmultple difficulties and challenges in attracting foreign investment.
文摘The development of a multiple level underground mine is a complex task in which geology,engineering,ground control,and unit operations are integrated into a single mine design.The components are interdependent and must function cohesively to ensure a profitable underground mining operation.To optimize reserve recovery,mine planning should begin from the lowest level and progress up.This limits any misjudgments or oversights of a given level affecting the underlying levels and ensures the ability to maximize recovery from each level.Mine planning should start with the exploration and characterization of the geologic setting.Once the reserve geology and quality is well understood,then mine planning can begin with respect to the following:(1)orientation of mine works with respect to horizontal stress;(2)access to the reserve;(3)determination of opening widths;(4)selection of back,floor horizons and pillar centers;(5)selection of development and secondary mining heights;(6)appropriate inter-burden thicknesses;and(7)examining the stability of the multiple level mine through numerical modeling.The multiple level mine design process and decisions are presented through a case history example.The theme is that there is one opportunity to"get it right"and many chances to overlook a small aspect within the design that will plague the mine throughout all levels and through the entirety of its operating life.
基金the National Key Research and Development Program of China (2018YFB0105000)the National Natural Science Foundation of China (61773234 and U1864203)+2 种基金the Project of Tsinghua University and Toyota Joint Research Center for AI Technology of Automated Vehicle (TT2018-02)the International Science and Technology Cooperation Program of China (2016YFE0102200)the software developed in the Beijing Municipal Science and Technology Program (D171100005117001 and Z181100005918001).
文摘An increasing number of drivers are relying on digital map navigation systems in vehicles or mobile phones to select optimal driving routes in order to save time and improve safety. In the near future, digital map navigation systems are expected to play more important roles in transportation systems. In order to extend current navigation systems to more applications, two fundamental problems must be resolved: the lane-level map model and lane-level route planning. This study proposes solutions to both problems. The current limitation of the lane-level map model is not its accuracy but its flexibility;this study proposes a novel seven-layer map structure, called as Tsinghua map model, which is able to support autonomous driving in a flexible and efficient way. For lane-level route planning, we propose a hierarchical route-searching algorithm to accelerate the planning process, even in the presence of complicated lane networks. In addition, we model the travel costs allocated for lane-level road networks by analyzing vehicle maneuvers in traversing lanes, changing lanes, and turning at intersections. Tests were performed on both a grid network and a real lane-level road network to demonstrate the validity and efficiency of the proposed algorithm.
基金the National Natural Science Foundation of China(No.60904066)
文摘This paper presents an adaptive path planner for unmanned aerial vehicles （UAVs） to adapt a real-time path search procedure to variations and fluctuations of UAVs’ relevant performances, with respect to sensory capability, maneuverability, and flight velocity limit. On the basis of a novel adaptability-involved problem statement, bi-level programming （BLP） and variable planning step techniques are introduced to model the necessary path planning components and then an adaptive path planner is developed for the purpose of adaptation and optimization. Additionally, both probabilistic-risk-based obstacle avoidance and performance limits are described as path search constraints to guarantee path safety and navigability. A discrete-search-based path planning solution, embedded with four optimization strategies, is especially designed for the planner to efficiently generate optimal flight paths in complex operational spaces, within which different surface-to-air missiles （SAMs） are deployed. Simulation results in challenging and stochastic scenarios firstly demonstrate the effectiveness and efficiency of the proposed planner, and then verify its great adaptability and relative stability when planning optimal paths for a UAV with changing or fluctuating performances.
文摘Climate change vulnerability assessment is an essential tool for identifying regions that are most susceptible to the impacts of climate change and designing effective adaptation actions that can reduce vulnerability and enhance long-term resilience of these regions.This study explored a framework for climate change vulnerability assessment in the new urban planning process in Jangwani Ward,Tanzania.Specifically,taking flood as an example,this study highlighted the steps and methods for climate change vulnerability assessment in the new urban planning process.In the study area,95 households were selected and interviewed through purposeful sampling.Additionally,10 respondents(4 females and 6 males)were interviewed for Focus Group Discussion(FGD),and 3 respondents(1 female and 2 males)were selected for Key Informant Interviews(KII)at the Ministry of Lands,Housing and Human Settlements Development.This study indicated that climate change vulnerability assessment framework involves the assessment of climatic hazards,risk elements,and adaptive capacity,and the determination of vulnerability levels.The average hazard risk rating of flood was 2.3.Socioeconomic and livelihood activities and physical infrastructures both had the average risk element rating of 3.0,and ecosystems had the average risk element rating of 2.9.Adaptive capacity ratings of knowledge,technology,economy or finance,and institution were 1.6,1.9,1.4,and 2.2,respectively.The vulnerability levels of socioeconomic and livelihood activities and physical infrastructure were very high(4.0).Ecosystems had a high vulnerability level(3.8)to flood.The very high vulnerability level of socioeconomic and livelihood activities was driven by high exposure and sensitivity to risk elements and low adaptive capacity.The study recommends adoption of the new urban planning process including preparation,planning,implementation,and monitoring-evaluation-review phases that integrates climate change vulnerability assessment in all phases.
文摘A smart city provides a new idea and model for urban construction, management, and development. This article proposes the concepts and methodology for top-level design of smart cities based on the ＂ Integration of Four Plans ＂, and the planning process and systems for implementing the top-level design of smart cities. This article discusses, from the perspective of a city, how to optimize resource allocation, coordinate the development of urban economy, society, resources, environment, and people＇s livelihood, and map out the blueprints for healthy and sustainable development of a smart city.
