Double BP Q-Learning Algorithm for Local Path Planning of Mobile Robot

Aiming at the dimension disaster problem, poor model generalization ability and deadlock problem in special obstacles environment caused by the increase of state information in the local path planning process of mobile robot, this paper proposed a Double BP Q-learning algorithm based on the fusion of Double Q-learning algorithm and BP neural network. In order to solve the dimensional disaster problem, two BP neural network fitting value functions with the same network structure were used to replace the two Q value tables in Double Q-Learning algorithm to solve the problem that the Q value table cannot store excessive state information. By adding the mechanism of priority experience replay and using the parameter transfer to initialize the model parameters in different environments, it could accelerate the convergence rate of the algorithm, improve the learning efficiency and the generalization ability of the model. By designing specific action selection strategy in special environment, the deadlock state could be avoided and the mobile robot could reach the target point. Finally, the designed Double BP Q-learning algorithm was simulated and verified, and the probability of mobile robot reaching the target point in the parameter update process was compared with the Double Q-learning algorithm under the same condition of the planned path length. The results showed that the model trained by the improved Double BP Q-learning algorithm had a higher success rate in finding the optimal or sub-optimal path in the dense discrete environment, besides, it had stronger model generalization ability, fewer redundant sections, and could reach the target point without entering the deadlock zone in the special obstacles environment.

AUV Local Path Planning Based on Acoustic Image Processing

The forward-looking image sonar is a necessary vision device for Autonomous Underwater Vehicles （AUV）. Based on the acoustic image received from forward-looking image sonar, AUV local path is planned. When the environment model is made to adapt to local path planning, an iterative algorithm of binary conversion is used for image segmentation. Raw data of the acoustic image, which were received from serial port, are processed. By the use of ＂Mathematic Morphology＂ to filter noise, a mathematic model of environment for local path planning is established after coordinate transformation. The optimal path is searched by the distant transmission （Dt） algorithm. Simulation is conducted for the analysis of the algorithm. Experiment on the sea proves it reliable.

Novel Algorithm for Mobile Robot Path Planning in Constrained Environment

This paper presents a development of a novel path planning algorithm, called Generalized Laser simulator (GLS), for solving the mobilerobot path planning problem in a two-dimensional map with the presence ofconstraints. This approach gives the possibility to find the path for a wheelmobile robot considering some constraints during the robot movement inboth known and unknown environments. The feasible path is determinedbetween the start and goal positions by generating wave of points in alldirection towards the goal point with adhering to constraints. In simulation,the proposed method has been tested in several working environments withdifferent degrees of complexity. The results demonstrated that the proposedmethod is able to generate efficiently an optimal collision-free path. Moreover,the performance of the proposed method was compared with the A-star andlaser simulator (LS) algorithms in terms of path length, computational timeand path smoothness. The results revealed that the proposed method hasshortest path length, less computational time and the best smooth path. Asan average, GLS is faster than A∗ and LS by 7.8 and 5.5 times, respectivelyand presents a path shorter than A∗ and LS by 1.2 and 1.5 times. In orderto verify the performance of the developed method in dealing with constraints, an experimental study was carried out using a Wheeled Mobile Robot(WMR) platform in labs and roads. The experimental work investigates acomplete autonomous WMR path planning in the lab and road environmentsusing a live video streaming. Local maps were built using data from a live video streaming with real-time image processing to detect segments of theanalogous-road in lab or real-road environments. The study shows that theproposed method is able to generate shortest path and best smooth trajectoryfrom start to goal points in comparison with laser simulator.

Co-management of small-scale fishery in the Tonle Sap Lake,Cambodia

In Cambodia,fishery co-management is an important process to transfer authority and ownership to the communities along the Tonle Sap Lake to manage fishery.This paper aims to determine why the co-management of small-scale fishery has not been implemented satisfactorily in the Tonle Sap Lake of Cambodia.The research was primarily based on a household survey among 404 house-holds for quantitative data,equally divided between the Cham(202 households)and Khmer(202 households).Participatory process was also applied to collect qualitative data from key stake-holders.We found that limited interaction among the involved stakeholders,i.e.,unequal distribution of authority and resources co-management,has impeded implementation.The engagement of fisherfolk was influenced by dependence on fishery,law enforcement,and events organized by the communities.While the Khmer had better opportunities to participate in planning at the provincial and district levels,the Cham were only engaged in local development activities initiated by their people.However,the latter evinced a higher rate of satisfaction due to their access tofishery resources and to a large quantity of fishing gear.In the future,efforts should be made to:(1)improve resource and authority sharing among all key stakeholders;(2)urgently resolve issues pertinent to capacity building,insufficient budgets for commune councils(CoCs)and community fishery(CFi);and(3)urge law enforcement regarding illegal fishing.

Sub-optimality analysis of mobile robot rolling path planning

Rolling planning is an efficient method for path planning in uncertain environment. In this paper, the general principle and algorithm of mobile robot path planning based on rolling windows are studied. The sub-optimality of rolling path planning is analyzed in details and explained with a concrete example.

A Topological Implementation for Motion Planning of a Robotic Arm

An efficient path planning algorithm based on topologic method is presented in this paper.The colli- sion free path planning for three-joint robotic arm consists of three parts:partition of C-space,construc- tion of CN and search for a path in CN.We mainly solved the problems of partitioning the C-space and judging the connectivity between connected blocks,etc.For the motion planning of a robotic arm with a gripper,we developed the concepts of global planning and local planning,and discussed the basic fac- tors for constructing the planning system.In the paper,some evaluation and analysis of the complexity and reliability of the algorithm are given,together with some ideas to improve the efficiency and increase the reliability.At last,some experimental results are presented to show the efficiency and accuracy of the nigorithm.

Mainstreaming Disaster Risk Reduction and Climate Change Adaptation in Comprehensive Development Planning of the Cities in Nueva Ecija in the Philippines

Recent scientific consensus suggests that climate-related disasters are becoming more frequent and destructive.Consequently,increasing importance is given to disaster risk reduction(DRR)and climate change adaptation(CCA)in global governance.The projected global warming at 1.5℃and the climate variability that the Philippine archipelago experiences make DRR-CCA the key priorities of both the national and local government units.In this study,we assessed and measured the degree of mainstreaming of DRR-CCA in the comprehensive development plans(CDPs)of the five component cities in the province of Nueva Ecija in the Philippines.These are among the areas in Central Luzon that are susceptible to hydrometeorological and geologic hazards.We distributed survey questionnaires to 25 employees of the local government units in the five component cities in Nueva Ecija who are directly involved in planning activities.We triangulated their responses using archival data(review of written policies and plans).The main findings of the study indicate that in spite the presence of laws and policies on DRR-CCA,their implementation is only in the preliminary stages.The results also provide insights to policymakers and future researchers on the challenges and opportunities influencing the systemic mainstreaming of DRR-CCA in the province.

Evaluating Nebraska’s local comprehensive plans to achieve the national wetland conservation missions in the USA

The U.S.federal government’s requirements and guidance for wetland conservation are reflected in a series of federal laws,regulations,and policies.However,the degree to which these requirements are reflected in local planning efforts is unclear.This study using five components with 56 indicators evaluates how well wetland conservation efforts are integrated into 112 local comprehensive plans in Nebraska,USA.The results show that the majority of local comprehensive plans pay little direct attention to wetland conservation,although many conservation efforts are conducted under the umbrella of environmental protection frameworks.The indicators include water resource protection received the highest score and was the descriptor of natural or environmental resources and resulted in the highest level of local awareness on natural assets.The indicator of setting goals for no net loss of wetlands received the lowest score among all indicators,demonstrating a clear gap between the national vision and the local reality of wetland conservation.Findings suggest local governments need more direct and proactive inputs to improve wetland conservation.Further findings from this research provide a practical roadmap for planners globally,particularly for the developing countries,to integrate wetland conservation into the local planning systems.