基于改进蚁群算法的植保无人机路径规划方法   总被引：1，自引：0，他引：1  

王宇  王文浩  徐凡  王泾涵  陈海涛 《农业机械学报》2020,51(11):103-112，92

为了规划出更加高效的植保无人机路径,提出一种基于改进蚁群算法的植保无人机路径规划方法,该方法适用于多个具有复杂多边形边界与内部障碍物的三维作业区域。采用扫描方式生成水平面内的作业路径,经过离散化处理后,在三维地形曲面上插值,获得三维作业路径。在此基础上,建立作业路径生成算法,以三维作业路径总长度尽量短、作业路径数量尽量少为目标,对植保无人机作业航向进行寻优。改进蚁群算法通过附加记录作业路径进入点的机制,实现对三维作业路径的合理排序,生成总长度较短的转移路径。经过算例检验,针对同一作业区域规划出的三维作业路径与水平面内的作业路径的航向角存在较大差异,相差最大为92°,这说明考虑三维地形的必要性。算例中,将改进的蚁群算法与贪婪算法进行了对比,针对一系列相同的作业起点,改进的蚁群算法所得的转移路径总长度均较短,比贪婪算法所得结果缩短3%~28%;在未选定作业起点情况下,改进的蚁群算法与贪婪算法求得的转移路径总长度最小值分别为1661m与1763m,说明改进的蚁群算法具有良好的寻优能力。实例检验情况与算例所得结论基本一致。算例与实例中的作业区域边界与地形复杂,涵盖情况全面,表明本文提出的路径规划方法具有一定实用性。  相似文献   

贵阳市植物景观规划设计探讨     

欧静  雷德宇 《中国园艺文摘》2009,25(11):82-85

对贵阳市植物景观现状调查分析,强调在城市总体规划中绿地同其它用地一样重要,植物景观规划应是城市绿地系统规划中重要一项。植物景观设计应遵循科学性与艺术性相结合的基本原则,要注重园林植物的形式美和意境美及体现地方文化特色。指出贵阳市植物景观特色的体现重要的一点就是向自然学习,体现植物的最佳适用性,把使用乡土树种、以乔木为主的植物配置从图纸上落实在建设中,以此推行节约型、生态型、可持续发展的园林绿化。最后列出几种宜于贵阳市的植物配置模式以供参考。  相似文献   

Tracking change in a human‐dominated landscape: developing conservation guidelines using freshwater fish     

Michael P. Carey  Martha E. Mather 《水产资源保护:海洋与淡水生态系统》2008,18(6):877-890

• 1. To conserve biodiversity in a human‐dominated landscape, a science‐based inventory and monitoring plan is needed that quantifies existing resources, isolates drivers that maintain natural communities, determines harmful stressors, and links ecological drivers and human stressors. A tactical approach is proposed for conservation planning using freshwater fish at the Cape Cod National Seashore.
• 2. Freshwater fish are well studied and occur across environmental gradients. The lentic systems at the national park are relatively pristine yet are enveloped by a region of high population density. Using fish community data, three steps were taken for tracking anthropogenic impacts in a human dominated landscape. First, fish and potential drivers were sampled intensively along a gradient to determine which fish metrics reflect natural communities and which abiotic and biotic factors structure them. Second, emerging and existing regional human threats were identified. Third, these human threats were linked to the potential drivers that maintain natural communities to identify the most informative metrics to monitor and track change.
• 3. Fish communities, water quality, habitat, and food resources were sampled concurrently in 18 ponds in 1999 and 2000. Three common fish species explained 98% of variation in numbers across systems. Based on ecological relationships, pH, depth, vegetation, prey, and community complexity were determined to maintain biodiversity of freshwater fish communities.
• 4. The primary human threats here included: development‐related, land‐use changes; non‐point source pollution; eutrophication from septic systems; and introduced species that are a byproduct of high human visitation. These are common threats in many rapidly urbanized areas and are likely to have relevance to many sites.
• 5. To track the impact of emerging threats to freshwater ponds related to increased human population, monitoring changes in water quality, vegetated habitat, fish diversity, and trophic interactions are recommended.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

基于栅格法的机器人路径规划   总被引：2，自引：0，他引：2  

王娟娟  曹凯 《农业装备与车辆工程》2009,(4)

阐述了基于栅格法的机器人路径规划算法问题.首先通过将不完全可行栅格归于完全可行栅格,在粗略划分整个工作环境的情况下,采用概率搜索方法,先获得一条次优最短路径,然后在此基础上,将不完全可行栅格还原到原工作环境,剔除无效栅格后,通过将栅格长度等比递减的策略,最终获得一条所需精度下的最短无碰撞路径.  相似文献   

Dispersal of woody plants in forest edges and hedgerows in a Southern Swedish agricultural area: the role of site and landscape structure     

Sarlöv Herlin  Ingrid L.  Fry  Gareth L.A. 《Landscape Ecology》2000,15(3):229-242

The distribution of woody vegetation was studied in forest edges and hedgerows in a 28 km² southern Swedish agricultural area, characterised by species-rich edge zones. The occurrence of 21 selected woody species (taxa) was related to differences in both edge structure and landscape structure. All the species studied were represented in both edge types, but a higher frequency of animal-dispersed species was found in hedgerows.Animal dispersed species were more affected by edge width and density than wind dispersed species. A higher number of wind-dispersed species were more frequent in forest edges, in hedgerows near to forest, or with a high proportion of forest within 500 m. A clear relationship was found between the number of physically connected elements in hedgerow networks and increasing frequency of occurrence for Corylus avellana, Crataegus spp., Euonymus europaeus, and Quercus robur; which indicate the ecological significance of connectedness for certain animal dispersed species. The study supports the general principle that woody species distribution and landscape structure are linked in a positive feedback loop. The results match findings from studies in other countries and are interpreted in the context of landscape processes and the ecological characteristics of woody plant species. We emphasise the importance of understanding dispersal mechanisms of woody species for the design and improvement of edge habitats in agricultural landscapes.  相似文献   

Allergenic pollen of ornamental plane trees in a Mediterranean environment and urban planning as a prevention tool     

《Urban Forestry & Urban Greening》2017

Green spaces and urban green infrastructure are new concepts in urban planning, and lately, the influence of green spaces in cities and how this presence affects local climate change have been taken into account. Moreover, some of the ornamental trees most used in cities provoke allergic symptoms in sensitized people. Due to the importance the plane trees in our parks and cities have as ornamental trees, this article assesses the urban Platanus airborne pollen concentration in the air of five cities of the SW Iberian Peninsula and tries to determine the differential factors that its distribution has by means of combining continuous monitoring of the air using volumetric spore traps and the geolocation of plane trees. They were counted separately according to the direction (Q1 NE, Q2 SE, Q3 SW, Q4 NW) around the spore trap location in circles of 100, 200, 300, 400, 500, 1000, 1500, 2000 and 2500 m in diameter. Pollen sums were distributed according to the predominant wind direction for each day. The highest concentrations for Platanus pollen were recorded in Don Benito. Differences amongst pollen stations were found and were mainly related to their degree of maturity and their proximity to spore traps, and finally, with the number of plane trees. Furthermore, other factors, as the pruning, which is different in each city and even in a more local way, affects pollination and is frequently unknown to aerobiological studies. The geolocation of ornamental trees can be a useful tool for providing summarized information about their behavioral differences amongst cities, which can be used to create healthy itineraries, minimizing the natural hazards in human health (allergic diseases) and could be implemented into a model to help policy-makers to create measures to improve green urban development.  相似文献   

Impacts of water resource planning on regional water consumption pattern: A case study in Dunhuang Oasis,China     

Xifeng ZHANG 《干旱区科学》2019,11(5):713-728

Water resources are critical for the existence and development of oases in endorheic basins. Thus, to enable sustainable development, it is fundamentally important to understand how to allocate and use these resources in a reasonable way. We therefore simulated and analyzed changes in water consumption pattern within the Dunhuang Oasis of China under three scenarios using a system dynamic model that corresponds to different water consumption pattern. This was done to assess the impacts of regional water resource planning (comprehensive planning of the rational use of water resource and protection of ecosystem services in the Dunhuang Basin) on water consumption pattern within the Dunhuang Oasis. The first of these, Scenario 1, is a baseline in which the status quo is maintained, while Scenario 2 incorporates the comprehensive effects of agricultural water-saving irrigation measures with an inter-basin water diversion project, and Scenario 3 focuses on ecological rehabilitation. In the baseline Scenario 1, the total water consumption within the Dunhuang Oasis increased progressively while agricultural water consumption remained extremely high and threatened overall ecological security. In contrast, Scenario 2 would decrease agricultural water consumption by almost 5.30×10⁷ m³ following the implementation of water-saving practices. The additional water allocated from an inter-basin water diversion project would play an important role in alleviating ecological strain on the oasis. Finally, in Scenario 3, the total irrigated land must be decreased to 20.6×10³ hm² by 2025 assuming that water supply for ecosystem restoration would be at least 50% of the total consumption. Although water resource planning plays a very important role in alleviating the ecological water crisis within the oasis, it is necessary to consider the suitable scale of oasis with regard to current water consumption pattern.  相似文献   

紫花苜蓿不同种植布局对苹果害虫及其天敌的影响     

张硕  刘锦  陈鹏  王晓  迟宝杰  尹淑艳  刘永杰 《中国果树》2019,(4):53-57

为探究紫花苜蓿不同种植布局对苹果园害虫及天敌的影响,在山东省沂水市苹果园设置了紫花苜蓿逐行、隔1行和隔2行种植的布局方式,以自然生草区为对照,系统调查了4种生草方式苹果园果树上和生草上害虫及天敌的发生动态。结果表明:害虫的调查总量,紫花苜蓿逐行种植区最少,比隔1行种植区少20.29%,比隔2行种植区少48.53%,比自然生草区少49.91%;苹果树上天敌的调查总量,紫花苜蓿隔1行种植区最多,是逐行种植区的1.13倍、隔2行种植区的1.29倍、自然生草区的1.78倍;生草上天敌的调查总量,紫花苜蓿逐行种植区最多,是隔1行种植区的1.05倍、隔2行种植区的1.19倍、自然生草区的1.66倍;益害比方面,紫花苜蓿逐行种植区和隔1行种植区的益害比明显高于其他生草区。综合防治效果和种植成本,紫花苜蓿隔1行种植的布局方式更合理。  相似文献   

基于DSP与超声波测距的农业机器人定位与避障控制   总被引：1，自引：0，他引：1  

王盟 《农机化研究》2017,(8):207-211

随着新兴电子集成技术和自动化技术的发展,控制系统已逐渐向数字化转变,高集成芯片广泛应用于自动化控制领域,体积小、运算能力强的嵌入式系统慢慢开始取代计算机。为此,首先分析了超声波测距功能及其优越性,采用三球定位技术,设计研究了一种基于DSP和超声波的全局定位系统;然后,采用多路超声波收发模块设计了基于超声波的自主避障控制系统,并提出一种新的模糊推理方法,实现机器人的避障和路径规划功能;最后,采用Visual C++可视化程序设计软件对避障系统进行仿真和场地试验,验证了系统的可靠性和可行性,为机器人的研究和发展提供了更加宽广的空间。  相似文献   

智能轨迹控制割草机器人设计——基于FPGA神经网络   总被引：1，自引：0，他引：1  

袁路路  张娓娓 《农机化研究》2017,(4):212-216

为了提高割草机器人自主导航和定位的精确性和智能性,设计了一种新型的基于FPGA神经网络算法的割草机器人。该设计采用FPGA可重构技术,以3层误差反向传播神经网络作为典型的模型来展开;利用成熟的BP算法公式,设计了割草机器人智能控制的模型;利用FPGA技术,设计了割草机器人的硬件系统;最后采用文本输入的设计方法,利用田间试验的方式,对机器人的轨迹规划能力和控制精度进行了验证。试验结果表明:利用FPGA和神经网络模型可以有效地穿越5个障碍物,并可得到满意的轨迹规划结果。将普通的PID控制器和神经网络PID控制器得到的控制结果误差进行了对比,结果表明:神经网络PID控制器得到的割草机器人控制误差明显比传统的PID控制器误差小。该方法为神经网络的硬件实现提供了可靠的理论基础。  相似文献