Improved lazy theta algorithm based on octree map for path planning of UAV

This paper investigates the path planning method of unmanned aerial vehicle(UAV)in threedimensional map.Firstly,in order to keep a safe distance between UAV and obstacles,the obstacle grid in the map is expanded.By using the data structure of octree,the octree map is constructed,and the search nodes is significantly reduced.Then,the lazy theta*algorithm,including neighbor node search,line-of-sight algorithm and heuristics weight adjustment is improved.In the process of node search,UAV constraint conditions are considered to ensure the planned path is actually flyable.The redundant nodes are reduced by the line-of-sight algorithm through judging whether visible between two nodes.Heuristic weight adjustment strategy is employed to control the precision and speed of search.Finally,the simulation results show that the improved lazy theta*algorithm is suitable for path planning of UAV in complex environment with multi-constraints.The effectiveness and flight ability of the algorithm are verified by comparing experiments and real flight.

Overall Planning of Development of Urban-Rural Areas:A Policy Mechanism for Urban-Rural Coordinated Growth

While analyzing overall planning and coordinated development of urban-rural areas, this paper shows that overall planning for the development of urban-rural areas is a requirement for the best use of productive forces. It means the setting up of a policy mechanism for coordinated growth. Recognizing this, the government should set up a way to lead and manage a unified program to increase service and decrease controlling administration power, while safeguarding and fulfilling the farmers' ownership to the means of production.

Development of suburb farm landscape in the process of urban-rural overall planning from the perspective of ecological economics:a case study of Chengdu City

With the accelerating development of Chinese urbanization and the widening gap between rural and urban areas,urban-rural overall planning is to be an inevitable choice for economic and social development.However,the specific patterns and methods in urban-rural overall planning are greatly different.From the persperctive of ecological economy,taking the main physical and biological pattern of the farmland as research objects,this paper analyzes the components and characteristics of farm landscape,the relationship between farm landscape exploitation and rural tourism,and the role of farm landscape exploitation in planning urban and rural development.It expatiates on the pattern,method and principle of farm landscape development.Furthermore,based on the actual development case,this paper explores how to make high-grade tourism products with scientific and reasonable farm landscape development method,how to increase peasant income,how to improve urban and rural ecological economic environment,so as to promote urban-rural overall planning.

利用内部信息的农用自动引导行走车的研究(第2报)——MAP(Map And Planning)系统

介绍农用自动引导行走车研究的地图和路径计划系统(MAP系统)。针对农业领域作业的实际情况,建立了农田的环境模型和环境地图,并采用图论的方法开发了路径计划系统,进而构造了路径地图。

A Flexible Multi-Layer Map Model Designed for Lane-Level Route Planning in Autonomous Vehicles

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.

Research on AGV task path planning based on improved A^(*) algorithm

Background Automatic guided vehicles(AGVs)have developed rapidly in recent years and have been used in several fields,including intelligent transportation,cargo assembly,military testing,and others.A key issue in these applications is path planning.Global path planning results based on known environmental information are used as the ideal path for AGVs combined with local path planning to achieve safe and rapid arrival at the destination.Using the global planning method,the ideal path should meet the requirements of as few turns as possible,a short planning time,and continuous path curvature.Methods We propose a global path-planning method based on an improved A^(*)algorithm.The robustness of the algorithm was verified by simulation experiments in typical multiobstacle and indoor scenarios.To improve the efficiency of the path-finding time,we increase the heuristic information weight of the target location and avoid invalid cost calculations of the obstacle areas in the dynamic programming process.Subsequently,the optimality of the number of turns in the path is ensured based on the turning node backtracking optimization method.Because the final global path needs to satisfy the AGV kinematic constraints and curvature continuity condition,we adopt a curve smoothing scheme and select the optimal result that meets the constraints.Conclusions Simulation results show that the improved algorithm proposed in this study outperforms the traditional method and can help AGVs improve the efficiency of task execution by planning a path with low complexity and smoothness.Additionally,this scheme provides a new solution for global path planning of unmanned vehicles.

Optimization of Map Compilation for County-level Land Consolidation Planning

Based on practice of the land consolidation planning in Changfeng County of Hefei City,taking full account of reality of land consolidation and its significance as livelihood project,we analyzed map compilation procedure.In combination with actual effect of land consolidation,we carried out consolidation assessment of same elements by overall planning method,and optimized the map compilation for county-level land consolidation planning.Results show that planning map of land consolidation potential is to be improved and legends should be merged.After consolidation of legends,it is convenient to apply in potential planning map and solve complicated problem of reading maps.

基于Gmapping和A*算法的运输机器人系统的设计

在流行病毒活跃的季节,为了降低室内隔离点的病毒交叉感染几率,减轻医护人员负担,设计了可以根据医护人员指令完成室内医疗货物运输的防疫辅助机器人。机器人由背部的NVIDIA Tegra X2计算单元运行Ubuntu操作系统用于算法设计与功能开发,配有显示器、键盘摄像头、激光雷达。系统利用GMapping算法实现了机器人的定位与建图,并利用改进的A*算法和动态窗口法融合的方式进行路径规划。仿真实验结果表明,机器人建图轮廓清晰,误差在允许范围内,午间运行轨迹平滑且成功躲避行人,可以在确保安全性的前提下应用在运输机器人领域。

Ant Colony Optimization with Potential Field Based on Grid Map for Mobile Robot Path Planning

For the mobile robot path planning under the complex environment,ant colony optimization with artificial potential field based on grid map is proposed to avoid traditional ant colony algorithm's poor convergence and local optimum.Firstly,the pheromone updating mechanism of ant colony is designed by a hybrid strategy of global map updating and local grids updating.Then,some angles between the vectors of artificial potential field and the orientations of current grid are introduced to calculate the visibility of eight-neighbor cells of cellular automata,which are adopted as ant colony's inspiring factor to calculate the transition probability based on the pseudo-random transition rule cellular automata.Finally,mobile robot dynamic path planning and the simulation experiments are completed by this algorithm,and the experimental results show that the method is feasible and effective.

The Concept of Using the Strategic Noise Maps inPlanning of Urban Space in Poland

In the territory of Poland the manner of urban space management is defined by a planning document called LLUP （local land use plan）. When analyzing the development process of Polish cities, an obvious conclusion emerges about the lack of complex studies and researches of the environment concerning the issue of acoustic climate. The procedures of development of local land use plan involve merely a general diagnosis of an environment excluding measured values of pollution, including noise levels. The main aim of this article is to introduce the issue of the influence that acoustic climate has on the urban space planning with the application of SNM （strategic noise mapping）. The map enables holistic assessment of the degree to which urban areas are exposed to noise, determines its sources and forecasts variations of its levels. Preliminary research results confirmed the necessity of including noise level influence in the procedures related to urban space planning especially concerning its forecasted levels resulting from estimates of local land use plans. Applying SNM in verification of conceptual space arrangements in terms of protection against noise in the preparation of LLUP as well as their further application in the plan is a considerable advantage.

The Application of MAPGIS in Basic Farmland Protection Plan Mapping

In this study,MAPGIS software was used in production of basic farmland protection plan maps based on the related practice of Jinkong town,Yanting County,Sichuan Province,China.It was proved that MAPGIS software could improve the efficiency of mapping greatly,and resolved technical problems in basic farmland protection plan mapping.

Changing Concepts of City and Urban Planning Practices in Guangzhou(1949–2010): An Approach to Sustainable Urban Development

By focusing on Guangzhou, this paper examines how different concepts of city in terms of urban-rural relationships are shaped in transforming China since 1949, and explores how they influence the way in which urban planning are practiced. In the pre-reform era, the city was defined as a productive space under the system of urban-rural segregation established for securing rapid industrialization. Urban planning was thus only concerned with the development of urban areas. In the 1980 s and 1990 s after the reform, institutional change and economic transformation mobilized the urban-rural linkages. The development of suburban areas was then considered by urban planning, but this consideration was a passive response to urban problems such as population explosion and water resources protection. Since the new millennium, the agenda for sustainable development and problems of uneven urban-rural development have called for the development of urban-rural integration. In this context, the city is conceptualized as a complex of mountain, city, river, farmland and sea, reconstructing the ideology of urban-rural division in defining urban development. Urban planning has therefore sought in an active way to develop a sustainable city embracing rural and natural elements, and to balance economic growth and environmental protection. It is argued that developing the concept of city as a complex of urban and rural elements contributes to the urban planning for sustainable urban development, while this conceptualization relies on the recognition of the integrated urban-rural relationship.

Three-dimension path planning for UAV using improved A＊ algorithm in complicated threat environment

In order to improve the battle effectiveness of the unmanned aerial vehicle （UAV） under the increasingly complex threat environment, a three-dimension path planning method based on an A ＊ al- gorithm is proposed and simulated in this paper which makes the UAV satisfy requirements of different missions. At first, the digital map information is processed vdth an integrated terrain smoothing algorithm, and a safe flight surface which integrates the vehicle dynamic is built and added on the terrain, and then, models of the complicated threats are established and integrated into the digital terrain. At last, an improved A ＊ algorithm is used to plan the three-dimension path on the safe sur- face, and then smooth the path. Simulation results indicate that the approach has a good perform- ance in creating an optimal path in the three-dimension environment and the path planning algorithm is more simple, efficient and easily realized in the engineering field.

Study on Low-carbon City Planning Strategies Based on Urban Greenhouse Gas Inventory

From the perspective of urban greenhouse gas inventory, this paper analyzed the composition and tendency of urban greenhouse gas inventory of Guangzhou, and compared greenhouse gas inventory of representative international cities. Taking Guangzhou Haizhu Eco-city for example, this paper from the perspective of urban-rural planning put forward the low-carbon development paths and strategies such as increasing carbon sink, industrial transformation, spatial restructuring, traffic organization, green civil engineering and resource utilization, and green building for the main carbon-emitting fields such as industry, energy supply, transport, building and waste disposal.

融合改进D*与Gmapping算法的自主导航仿真研究

为了实现移动机器人在未知环境下能够同时进行自主建图与导航,首先通过引入障碍物距离影响系数和四点式的梯度下降法优化了D*算法在动态路径规划时出现效率低下和路径不平滑问题。其次通过梯度式增加粒子数和扫描匹配迭代次数,改善了Gmapping建图容易出现模糊和重叠的现象。接着将优化后的Gmapping算法和基于改进D*算法的全局规划器、基于Teb算法的局部规划器,放在同一tf树下,并加入延时决策设计,融合集成了一个在ROS平台下的自主导航模块。最后仿真结果验证了上述方法实现自主建图与导航的可行性,能够在同时建图与导航的基础上,保证建图的准确性与路径的最佳选取。

Feasibility of a Direct-Conversion Method from Magnetic Susceptibility to Relative Electron Density for Radiation Therapy Treatment Planning

Recently, several institutions have been developing magnetic resonance imaging (MRI)-guided radiotherapy treatment systems. In this study, we examine whether it is possible to perform radiation therapy planning (RTP) using a magnetic susceptibility map obtained using MRI. The head of a healthy volunteer was scanned using dual-energy computed tomography (CT) and MRI. A T2-star-weighted 3D gradient echo-based sequence (GRE) with images taken at four different echo times was acquired using the MRI scanner. The CT images were converted to relative electron density (rED) using a predefined ΔCT-rED conversion table. ΔCT was derived using the energy-subtraction method. The rED map was obtained from a single-linear relationship with the ΔCT-rED conversion table, whereas the magnetic susceptibility map was obtained from quantitative susceptibility mapping (QSM) via MRI. Subsequently, to obtain the relationship between the magnetic susceptibility and the rED, the rED map was rigidly aligned to the susceptibility map and resampled at the susceptibility map’s resolution. Finally, the magnetic susceptibility rED conversion table was obtained via voxel-by-voxel mapping between the two maps. No strong relationship between magnetic susceptibility and rED was obtained in the healthy volunteer’s head or in this study. The coefficient correlation between these parameters was 0.0145. Magnetic susceptibility values may be not able to convert to rED using our proposed method in healthy volunteer’s head. In contrast to the magnetic-susceptibility values obtained from the QSM algorithm, which were strongly affected by calcification and iron content, the rED or CT number was not considerably affected by such materials.

Geospatial Analysis of Geotechnical Data Applied to Urban Infrastructure Planning

The urbanization process inside the State of S?o Paulo (Brazil) facilitated, in approximately five decades, the migration of thousands of peasants to the urban areas of great industrial centers inducing and requesting, at the same time and very often, an amplification of the systems of local urban infrastructure not appropriate for the natural potential of the physical territory. In this content, the city of S?o José do Rio Preto (State of S?o Paulo) with little more than 350.000 inhabitants, currently faces serious problems related to the urban planning originating from the unusual occupation and without previous study of suitability. Therefore, the present paper intends to guide and indicate the areas whose potential of urban development leads to an occupation suitable for the construction of shallow foundations in residential buildings of single floor, using an interpretative chart produced by the software GIS-SPRING-4.0 developed by Instituto Nacional de Pesquisas Espaciais/INPE (Brazil), and based in the methodology of geotechnical mapping developed by the department of geotechnical engineering of EESC/USP (Brazil). The chart for shallow foundation shows that a large portion of the studied area presents serious relationship problems with layers of highly collapsible soils.

A Bicycle Tourism Based Study on Planning and Designing of Urbanrural Recreational Greenway--A Case Study of Harbin City

The types of urban-rural recreational greenways were summarized,based on bicycle tourism and their planning methodology was explored.Taking the urban and rural areas of Harbin City as the research objects,the current situation of urban-rural recreational greenway environment and tourism resources was investigated and the evaluation system of bicycle tourism resources was established and tourism resources were evaluated according to the AHP-fuzzy comprehensive evaluation method to select suitable resources for bicycle tourism.Through the ArcGIS software,the currently available resources(rivers,wetlands,transportations and urban-layout)and suitable bicycle tourism resources were superimposed,and the spatial pattern planning and classification planning of urban-rural recreational greenway based on bicycle tourism were carried out.To the end,insights for the development of urbanrural recreational greenway in the future were provided.

Land-Use Planning Guidelines for Optimal Coastal Environmental Management

The objective of this study is to weigh and recommend environmentally-optimal regional land-use planning guidelines for coastal regions. The present malaise is assessed, as regards inefficiencies, non-suitability, non-sustainability, enhancing factors of environmental degradation, and potentially destructive consequences of current land-use alteration. Desired situations and goals are considered, and means are proposed for bridging the gap between the present malaise and a desired situation, based on five key approaches developed by the authors. Specific examples of regional approaches are presented. Guidelines and operational measures for sound regional planning the authors have employed in similar circumstances are recommended.

Localizing the Language Network with fMRI and Functional Connectivity: Implications for Pre-Surgical Planning

Object: Functional MRI is frequently applied to lateralize language in pre-surgical planning, with potential to localize functionally important cortex too. Here we present BOLD signal activation maps and related functional connectivity, in response to three commonly administered fMRI language tasks. Methods: Datasets from 55 pre-surgical fMRI studies were analyzed. Verbal response naming, covert word generation and passive listening tasks were administered in all studies. Single-subject analyses, group analyses and region-of-interest analyses were conducted, and a multi-subject functional connectivity analysis was performed. Results: Single-subject analyses revealed that clinically important language regions were activated in all but three patients using the panel of tasks. Group analyses revealed significant bilateral BOLD signal increases in anterior and posterior language regions in response to verbal response naming and bilateral signal increase in posterior language regions only in response to passive listening. Covert word generation activated anterior language regions bilaterally and posterior language cortex in the dominant hemisphere. Functional connectivity analyses confirmed that activated regions were significantly correlated in all tasks. Conclusion: The findings of single-subject and group analyses add to the evidence supporting the use of a panel of fMRI tasks to map the language network for pre-surgical planning. Our findings support the additional use of functional connectivity analysis in routine language mapping to add to the localization value to fMRI. In addition, the results of our investigation demonstrate these three commonly applied tasks reliably activate unique aspects of the language network, which advocates closer individual inspection, guided by the surgical intervention planned.