32,525 research outputs found

    Tree pruning/inspection robot climbing mechanism design, kinematics study and intelligent control : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronics at Massey University, Manawatu Campus, New Zealand

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    Forestry plays an important role in New Zealand’s economy as its third largest export earner. To achieve New Zealand Wood Council’s export target of $12 billion by 2022 in forest and improve the current situation that is the reduction of wood harvesting area, the unit value and volume of lumber must be increased. Pruning is essential and critical for obtaining high-quality timber during plantation growing. Powerful tools and robotic systems have great potential for sustainable forest management. Up to now, only a few tree-pruning robotic systems are available on the market. Unlike normal robotic manipulators or mobile robots, tree pruning robot has its unique requirements and features. The challenges include climbing pattern control, anti-free falling, and jamming on the tree trunk etc. Through the research on the available pole and tree climbing robots, this thesis presents a novel mechanism of tree climbing robotic system that could serve as a climbing platform for applications in the forest industry like tree pruning, inspection etc. that requires the installation of powerful or heavy tools. The unique features of this robotic system include the passive and active anti-falling mechanisms that prevent the robot falling to the ground under either static or dynamic situations, the capability to vertically or spirally climb up a tree trunk and the flexibility to suit different sizes of tree trunk. Furthermore, for the convenience of tree pruning and the fulfilment of robot anti-jamming feature, the robot platform while the robot climbs up should move up without tilting. An intelligent platform balance control system with real-time sensing integration was developed to overcome the climbing tilting problem. The thesis also presents the detail kinematic and dynamic study, simulation, testing and analysis. A physical testing model of this proposed robotic system was built and tested on a cylindrical rod. The mass of the prototype model is 6.8 Kg and can take 2.1 Kg load moving at the speed of 42 mm/s. The trunk diameter that the robot can climb up ranges from 120 to 160 mm. The experiment results have good matches with the simulations and analysis. This research established a basis for developing wheel-driven tree or pole climbing robots. The design and simulation method, robotic leg mechanism and the control methodologies could be easily applied for other wheeled tree/pole climbing robots. This research has produced 6 publications, two ASME journal papers and 4 IEEE international conference papers that are available on IEEE Xplore. The published content ranges from robotic mechanism design, signal processing, platform balance control, and robot climbing behavior optimization. This research also brought interesting topics for further research such as the integration with artificial intelligent module and mobile robot for remote tree/forest inspection after pruning or for pest control

    Correct-by-Construction Tactical Planners for Automated Cars

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    One goal of developing automated cars is to completely free people from driving tasks. Automated cars that require no human driver need to handle all traffic situations that a human driver is expected to handle, and possibly more. Although human drivers cause a lot of traffic accidents, they still have a very low accident and failure rate that automated systems must match.Tactical planners are responsible for making discrete decisions during the coming seconds or minute. As with all subsystems in an automated car, these planners need to be supported with a credible and convincing argument of their correctness. The planners\u27 decisions affect the environment and the planners need to interact with other road users in a feedback loop, so the correctness of the planners depend on their behavior in relation to other drivers and the environment over time. One possibility to ascertain their correctness is to deploy the planners in real traffic. To be sufficiently certain that a tactical planner is safe by that methods, it needs to be tested on 255 million miles without having an accident.Formal methods can, in contrast to testing, mathematically prove that the requirements are fulfilled. Hence, they are a promising alternative for making credible arguments of tactical planners\u27 correctness. The topic of this thesis is how formal methods can be used in the automotive industry to design safe tactical planners. What is interesting is both how automotive systems should be modeled in formal frameworks, and how formal methods can be used practically within the automotive development process.The main findings of this thesis are that it is natural to express desired properties of tactical planners in formal languages and use formal methods to prove their correctness. Model Checking, Reactive Synthesis, and Supervisory Control Theory have been used in the design and development process of tactical planners, and all three methods have their benefits, depending on the application.Formal synthesis is an especially interesting class of formal methods because they can automatically generate a planner based on requirements and models. Formal synthesis removes the need to manually develop and implement the planner, so the development efforts can be directed to formalizing good requirements on the planner and good assumptions on the environment. However, formal synthesis has two limitations: the resulting planner is a black box that is difficult to inspect, and it is difficult to find a level of abstraction that allows detailed requirements and generic planners

    School Leadership Interventions Under the Every Student Succeeds Act: Evidence Review - Updated and Expanded

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    This RAND analysis offers guidance to states and districts on how they can choose to use the Every Student Succeeds Act to help achieve their school improvement goals by supporting principals and other school leaders

    A Survey of the Fifty States to Determine Design Standards for the Multiple Car Method

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    A survey of the supervisors of traffic safety education programs of the fifty states was conducted to determine what, if any, design standards or guidelines were imposed upon school districts when designing multiple-car facilities for use in traffic safety education programs. From the information gathered it is apparent that many states are improving the pupil-teacher ratio through the inclusion of the multiple-car methods of instruction and thereby reducing the cost of the traffic safety education programs. However, only two states, Texas and Minnesota, had well-defined minimum standards for the design and approval of such facilities in approved programs. Georgia and Tennessee had suggested sizes and inclusion of certain exercises but had no requirements as all of the other states had indicated

    Development and Initial Findings of an Implementation Process Measure for Child Welfare System Change

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    This article describes a new measure designed to examine the process of implementation of child welfare systems change. The measure was developed to document the status of the interventions and strategies that are being implemented and the drivers that are being installed to achieve sustainable changes in systems. The measure was used in a Children’s Bureau-supported national effort to assess the ongoing implementation of 24 systems-change projects in child welfare jurisdictions across the country. The article describes the process for measure development, method of administration and data collection, and quantitative and qualitative findings

    Mapping the Implementation Landscape: Assessing the Systemic Capacity of Statewide Community Corrections Agencies to Deliver Evidence-Based Practices

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    Treatment quality is recognized as a critical moderator for programs to successfully reduce recidivism. Yet, the implementation of any new initiative takes place within a context—a system comprised of varying structures, norms, policies, and relationships to external stakeholders. Surprisingly little evidence exists about how to build organizational capacity to successfully achieve program fidelity and sustain innovations over time. This study provides results from a process evaluation measuring implementation capacity to deliver evidence-based practices (EBPs) in the state of Oregon. Using the ImpleMap interview procedure created by the National Implementation Research Network, findings from ten county-level community corrections agencies demonstrated how systemic, actionable implementation can be facilitated. Aggregate statewide patterns of organizational capacity emerged, as well as individual variation in the strengths and gaps of implementation among each county. By understanding county-level variation, we reveal that sustainable implementation requires purposeful attention to systemic capacities that go beyond training and coaching. To advance the science and practice of offender rehabilitation, we need to broaden our focus to rediscover the importance of process, structure, and context. Responsibility for change needs to shift from individuals to implementation systems.This research was supported by Award Number 2012-SM-BX-0004, awarded by the Bureau of Justice Assistance, Office of Justice Programs. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the U.S. Department of Justice

    Towards an Improved Safety Benefit Assessment for Heavy Trucks - Introduction of a framework for the combination of different data sources

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    Although heavy goods vehicles (HGVs) were only involved in 4.4% out of more than 1 million crashes that occurred on European roads in 2017, their share in crashes with fatal outcome was almost three times larger (12%). Advanced Driver Assistance Systems (ADAS) have the potential to mitigate the consequences of these crashes or avoid them altogether. In order to prioritise the most promising system, several types of safety benefit assessment are performed separately and independently of each other. These assessments miss however a combination into a common output, i.e. they are not able to provide a holistic overview but only show compartmentalised results.The first objective of this thesis is to provide a framework that can incorporate multiple data sources and combine their results into one common safety benefit output. The proposed framework within this thesis is based on Bayesian modelling and can update prior information (e.g. simulation results of a new ADAS) with new observations (e.g. test track results of the ADAS). The framework can incorporate additional information such as user acceptance and market penetration of the ADAS for an improved benefit assessment. The output of the framework can easily be incorporated as prior knowledge in new safety benefit assessments, e.g. when new data is available.The second objective is to prepare the application of the framework for the assessment of the safety benefit associated to the introduction of new ADAS for long-haul trucks. In order to specify the most critical crash scenarios for HGVs in Europe, a detailed, three-level analysis of crashes involving long-haul trucks was performed, starting on a general European level and going to in-depth crash data. The identified target scenarios are (a) rear-end crashes with the truck as the striking vehicle, (b) crashes between a right-turning truck and adjacent cyclist and (c) crashes between a truck and a pedestrian crossing in front of the truck. These three scenarios should be the basis for ADAS development and further addressed by driver behaviour modelling in the future.Future work will focus on improving simulation results by incorporating more accurate driver models, that are better able to represent truck driver behaviour, e.g. brake or steering reactions. These models will help to obtain more valid simulation results, and thereby increase the output quality of the framework
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