Adaptive Space Expansion for Fast Motion Planning

The sampling process is very inefficient for sam-pling-based motion planning algorithms that excess random sam-ples are generated in the planning space.In this paper,we pro-pose an adaptive space expansion(ASE)approach which belongs to the informed sampling category to improve the sampling effi-ciency for quickly finding a feasible path.The ASE method enlarges the search space gradually and restrains the sampling process in a sequence of small hyper-ellipsoid ring subsets to avoid exploring the unnecessary space.Specifically,for a con-structed small hyper-ellipsoid ring subset,if the algorithm cannot find a feasible path in it,then the subset is expanded.Thus,the ASE method successively does space exploring and space expan-sion until the final path has been found.Besides,we present a particular construction method of the hyper-ellipsoid ring that uniform random samples can be directly generated in it.At last,we present a feasible motion planner BiASE and an asymptoti-cally optimal motion planner BiASE*using the bidirectional exploring method and the ASE strategy.Simulations demon-strate that the computation speed is much faster than that of the state-of-the-art algorithms.The source codes are available at https://github.com/shshlei/ompl.

Coordinated Planning Transmission Tasks in Heterogeneous Space Networks:A Semi-Distributed Approach

This paper studies the coordinated planning of transmission tasks in the heterogeneous space networks to enable efficient sharing of ground stations cross satellite systems.Specifically,we first formulate the coordinated planning problem into a mixed integer liner programming(MILP)problem based on time expanded graph.Then,the problem is transferred and reformulated into a consensus optimization framework which can be solved by satellite systems parallelly.With alternating direction method of multipliers(ADMM),a semi-distributed coordinated transmission task planning algorithm is proposed,in which each satellite system plans its own tasks based on local information and limited communication with the coordination center.Simulation results demonstrate that compared with the centralized and fully-distributed methods,the proposed semi-distributed coordinated method can strike a better balance among task complete rate,complexity,and the amount of information required to be exchanged.

Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology

China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area.

Wind and Snow Impacts on Urban Space Planning:A Multiphase Numerical Simulation

The wind and snow environment outside the planned space plays a key role in the comfort and safety of the human habitat in severe cold regions. Traditional studies of the external environment of human settlements, however, frequently overlook the combined impacts of wind and snow environments. Furthermore, in urban meteorological studies, it is impossible to accurately assess the wind and snow environment in specific areas or locations. In this study, a refined Computational Fluid Dynamics(CFD) multiphase flow numerical method was used to simulate a planning space's wind and snow environment. The study classified the Snowstorm Weather Grade(SWG) by incorporating the Snowstorm Weather Index(SWI) to generate calculation results of the wind environment and snow environment. In particular, 150 measurement points in the planning space were chosen for analysis and evaluation of their wind and snow environments. The results demonstrated that the SWI index can effectively correlate to the wind and snow environment calculation results. In addition, the graph of SWI showed that 55% of the measurement points had a moderate wind and snow grade SWI, which exceeds the average grade for the entire region. The practical application shows that the wind and snow environment assessment indexes and technical methods developed in this paper can be successfully applied to wind and snow environment studies in other cold cities.

Landscape Planning and Design of Urban Waterfront Green Spaces

Definition of urban waterfront green spaces is given,its design principles are summarized as:human-centered,ecology-first,integrated nature and humanity,highlighting regional characteristics,unified planning and overall coordination.Design of ecological plant community,design of traffic network and revetment management is analyzed to explore design contents and techniques of urban waterfront green spaces.In terms of the design of ecological plant community,the selection of landscape plants and landscaping of waterfront green spaces are analyzed;traffic network is further classified into water traffic,waterfront pathway,and driveway system;waterfront revetment management is specifically discussed from the original natural revetment,natural revetment reinforced by natural designs,and natural revetment reinforced by artificial designs.Problems in the modern urban waterfront green spaces are proposed,such as contradictions between diversified functions and simple designs,lack of regional characteristics,viewers are kept away from water;countermeasures are also given in the hope of pushing urban waterfront green spaces in a healthy development road,so as to improve the overall landscape quality of urban waterfront green spaces.

Ecological Planning for Urban Green Space System——A Case Study of Chongqing Economic and Technological Development Zone

Based on overview of development history and research advances of do- mestic and foreign urban green space system planning, this paper made clear rele- vant concepts of the urban green space system. Urban green space system is a key region for protecting ecological resources. Taking Chongqing Economic and Technological Development Zone as an example, on the basis of in-depth survey, it made a systematic study on green space system planning combining current situa- tions of green space and regional spatial characteristics of Chongqing Economic and Technological Development Zone. It discussed how to restore and build urban green space system, protect ecological environment, and promote regional economic de- velopment and harmony between human and nature through design of ecological technologies and landscape in the ecological planning of urban green space system.

Analysis on the Green Space System Planning of Small Cities in Mountainous Areas

With the urban green space system planning of small cities in mountainous areas as the study object,the planning practices are analyzed and studied to summarize the common characteristics of urban green space system planning in those small cities.Being combined with relevant national standards and regulations,the problems that those small cities are faced with in their urban green space system planning are analyzed,then corresponding countermeasures and suggestions are put forward to resolve problems in the practical planning.

Study on the Planning of Urban Green Space System in the Precinct Area of Dali City

This paper elaborated natural conditions of Dali City,jurisdictions which included 2 offices,2 towns,89 village offices and 429 natural villages,and planning scope which contained the precinct area of Dali City and covers a total area of 1 815 km2.In accordance with the urban development space and functional layout of "one lake,two lines and two slices"("one lake" refers to Erhai Lake;"two lines" stands for the area in the east and west of Erhai Lake;"two slices" indicates the area in the north and south of Erhai Lake),based on the construction of provincial and national garden city and of large landscape city,green spatial network system with the combination of "spot","line" and "surface" was put forward,so as to manifest "largeness","wideness","harmony" and "linkage".And finally,the planning structure of green space system of "two circles,two slices,four belts,seven spots and eighteen waterfronts area"("two circles" refers to the area around the lake and the area around the mountain,"two slices" stands for the area in the north and south of Erhai Lake,"four belts" means four landscape belts of the garden city,"seven spots" indicates the seven green landscape spots in villages and towns,"eighteen waterfronts area" is colored green belt in eighteen stream's basin) was proposed.

Analysis of the Green Space System Planning in Small Towns with Yifeng Township, Yancheng City as an Example

Taking the green space systems in Yifeng Township for an example, this paper analyzed the characteristics and planning principles of green space system in small towns under the background of rapid urbanization. It also proposed the construction of stable ecological green space pattern of towns, the development of forest-type green space and the planning ideas of green space system in small towns that can embody regional context and implement multifunctional composite.

Green Space System Planning of Huaiyang County in Henan Province

The characteristics of small cities in Henan Province were summarized in this study, with Huaiyang County as an example, guiding concepts, goals and contents of green space system planning of county-level cities in Henan Province were analyzed through reviewing the general situation of its green space system and the planning of green space system in the construction of garden cities.

Trajectory Planning for OTFS-Based UAV Communications

Unmanned aerial vehicles(UAVs)have attracted growing research interests in recent years,which can be used as cost-effective aerial platforms to transmit collected data packets to ground access points(APs).Thus,it is crucial to investigate robust airto-ground(A2G)wireless links for high-speed UAVs.However,the A2G wireless link is unstable as it suffers from large path-loss and severe Doppler effect due to the high mobility of UAVs.In order to meet these challenges,we propose an orthogonal time frequency space(OTFS)-based UAV communication system to relief the Doppler effect.Besides,considering that the energy of UAV is limited,we optimize the trajectory planning of UAV to minimize the energy consumption under the constraints of bit error rate(BER)and transmission rate,where the Doppler compensation is taken into account.Simulation results show that the performance of OTFS-based UAV system is superior to orthogonal frequency division multiplexing(OFDM)-based UAV systems,which can accomplish transmission tasks over shorter distances with lower energy consumption.

Analysis of problems in urban green space system planning in China

This paper discusses the major problems in urban green space system （UGSS） planning at both general and special planning levels in China. At general planning level, the problems of the UGSS are mainly from the ignorance in the characteristics of urban nature spaces and the limitation factors of the urban planning system. Great importance is attached to the green spaces in the built area of city, but the green spaces in surrounding areas of the city is unnoticed. Furthermore, because the area of UGSS planning is strictly limited by the administrative zoning, the green space system loses its integrity and rationality in spatial patterns. The schedules of urban development planning mismatched the paces and progresses of the ecological restoration cycles. At special plan level, the problem of the UGSS in China is that the green spaces quantity was over emphasized but the rationality of their layouts is neglected.. Meanwhile, the requirement of the spatial structures and the green spaces layouts to balance between the urban development and the natural ecological environments is often ignored. With regard to the layouts in the UGSS planning practices, the existing problems are the compromising to the existing land-uses, the ＇filling in＇ approach to plan green spaces and an over-emphasis on the layout patterns.

User-oriented data acquisition chain task planningalgorithm for operationally responsive space satellite

With the development of operationally responsive space（ORS） and on-board processing techniques, the end users canreceive the observation data from the ORS satellite directly. Tosatisfy the demand for reducing the requirements-tasking-effectscycle from one day to hours, the various resources of the wholedata acquisition chain （including satellites, ground stations, dataprocessing centers, users, etc.） should be taken into an overallconsideration, and the traditional batch task planning mode shouldbe transformed into the user-oriented task planning mode. Consideringthere are many approaches for data acquisition due tothe new techniques of ORS satellite, the data acquisition chaintask planning problem for ORS satellite can be seen as the multimodalroute planning problem. Thereby, a framework is presentedusing label-constrained shortest path technique with the conflictresolution. To apply this framework to solve the ORS satellite taskplanning problem, the preprocessing and the conflict resolutionstrategies are discussed in detail. Based on the above work, theuser-oriented data acquisition chain task planning algorithm forORS satellite is proposed. The exact solution can be obtainedin polynomial time using the proposed algorithm. The simulationexperiments validate the feasibility and the adaptability of the proposedapproach.

Planning Overall Landscapes,Building a Garden City:on the Revision of Guangzhou Urban Green Space System Planning

The concept of urban green space system planning was proposed after analyzing the background of compiling Guangzhou green space system planning and current situation of local green spaces,i.e. design landscape pattern of Guangzhou City during urban agglomeration of the Pearl River Delta,and highlight Lingnan cultures(Lingnan refers to south of the Five Ridges) and features of "Flower City"(another name of Guangzhou). Key points of planning are protecting ecological barriers in the north,improving urban garden structure in the center,using wetland reasonably in the south,to maintain integrality and continuity of the landscape pattern.

Planning of Urban Public Disaster-prevention Green Spaces: A Case Study of Living Water Park in Chengdu City

Based on disaster-prevention functions of urban public green spaces, necessity and significance of emergency shelters in a city were analyzed. Taking Living Water Park in Chengdu for example, planning of urban public disaster-prevention green spaces was analyzed to further explore planning of urban disaster-prevention green space system and refugee spaces, and provide instructions for the planning and construction of urban disaster-prevention green spaces in China.

Science Research and Utilization Planning of China’s Space Station in Operation Period 2022–2032

The core module of China’s Space Station(CSS)is scheduled to be launched around the end of 2020,and the experimental module I and II will be launched in the next two years.After on-orbit constructions,CSS will be transferred into an operation period over 10 years(2022–2032 and beyond)to continuously implement space science missions.At present,based on the project selection and research work in the ground development period of CSS,China is systematically making a utilization mission planning for the operation period,which focuses on the fields of aerospace medicine and human research,space life science and biotechnology,microgravity fluid physics,combustion science,materials science,fundamental physics,space astronomy and astrophysics,Earth science,space physics and space environment,space application technology,etc.In combination with the latest development trend of space science and technology,China will continue to update planning for science research and technology development,carry out project cultivation,payload R&D,and upgrade onboard and ground experiment supporting systems to achieve greater comprehensive benefits in science,technology,economy,and society。

Green Space System Planning in Shuangcheng City and Creation of the City's Characteristics

Characteristic urban construction has already become a trend of modern social development,in this context,components of characteristic urban green spaces,and ways of demonstrating features of urban green space system were analyzed.Shuangcheng City in Heilongjiang Province was taken for example to analyze planning objectives and principles of characteristic urban green space system.Moreover,the green space layout of "A Hundred Years Old Castle,A Hundred of Enterprises and A Hundred of Gardens" was introduced.It was proposed that green space system planning suited to the development features and ecological conditions of the city should be developed from the perspective of greater regional environment,historical and cultural deposits,urban development pattern and lifestyle of the locals,so as to create urban green space system with regional features.

Space station short-term mission planning using ontology modelling and time iteration

This paper studies the problem of the space station short-term mission planning, which aims to allocate the executing time of missions effectively, schedule the corresponding resources reasonably and arrange the time of the astronauts properly. A domain model is developed by using the ontology theory to describe the concepts, constraints and relations of the planning domain formally, abstractly and normatively. A method based on time iteration is adopted to solve the short-term planning problem. Meanwhile, the resolving strategies are proposed to resolve different kinds of conflicts induced by the constraints of power, heat, resource, astronaut and relationship. The proposed approach is evaluated in a test case with fifteen missions, thirteen resources and three astronauts. The results show that the developed domain ontology model is reasonable, and the time iteration method using the proposed resolving strategies can successfully obtain the plan satisfying all considered constraints.

Genius Loci of Urban Public Spaces: A Case Study of Daihu Lake Landscape Planning in New Shouzhan District, Changle City, Fujian Province

Connotations of genius loci of urban public spaces were explored, geographical position and composition of Daihu landscape design in New Shouzhan District, Changle City, Fujian Province was introduced. Design concepts, layouts and patterns were summarized by combining with geographical and cultural conditions of the study area. Functional zoning of Daihu landscape design was analyzed, human-centered site planning stressed to realize functions of new urban public spaces, regression of cultural and humanistic properties of these spaces, so as to provide diverse options for the future construction of urban public spaces.

Ecological Planning and Design of Urban Green Space System of Sanya City

The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.