Sensible heat flux is an essential quantity in the surface energy budget. Information about it is crucial for the derivation of models of air-surface interaction which in turn are needed for larger scale climate model...
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Sensible heat flux is an essential quantity in the surface energy budget. Information about it is crucial for the derivation of models of air-surface interaction which in turn are needed for larger scale climate models. Sensible heat flux varies greatly across short distances and thus many sensors are required in order to obtain measurements of sufficient spatial density. The standard measurement method however requires expensive equipment which constrains the deployment of a large number of sensors. Our work implements a method relying only on the variance of the measured temperature to compute the sensible heat flux. We first verify the validity of this method and then modify Sensorscope, a commercially available weather station, to capture the required data. The resulting setup is able to provide sensible heat flux measurements with high spatial density in near real time at negligible additional cost.
Self-assembly is a key coordination mechanism for large multi-unit systems and a powerful bottom-up technology for micro/nanofabrication. Controlled self-assembly and dynamic reconfiguration of large ensembles of micr...
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Self-assembly is a key coordination mechanism for large multi-unit systems and a powerful bottom-up technology for micro/nanofabrication. Controlled self-assembly and dynamic reconfiguration of large ensembles of microscopic particles can effectively bridge these domains to build innovative systems. In this perspective, we present SelfSys, a novel platform for the automated control of the fluidic self-assembly of microparticles. SelfSys centers around a water-filled microfluidic chamber whose agitation modes, induced by a coupled ultrasonic actuator, drive the assembly. Microparticle dynamics is imaged, tracked and analyzed in real-time by an integrated software framework, which in turn algorithmically controls the agitation modes of the microchamber. The closed control loop is fully automated and can direct the stochastic assembly of microparticle clusters of preset dimension. Control issues specific to SelfSys implementation are discussed, and its potential applications presented. The SelfSys platform embodies at microscale the automated self-assembly control paradigm we first demonstrated in an earlier platform.
In the context of robotics and automation, learning from demonstration (LfD) is the paradigm in which robots acquire new skills by learning to imitate an expert. The choice of LfD over other robot learning methods is ...
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In the context of robotics and automation, learning from demonstration (LfD) is the paradigm in which robots acquire new skills by learning to imitate an expert. The choice of LfD over other robot learning methods is compelling when ideal behavior can be neither easily scripted (as is done in traditional robot programming) nor easily defined as an optimization problem, but can be demonstrated. While there have been multiple surveys of this field in the past, there is a need for a new one given the considerable growth in the number of publications in recent years. This review aims to provide an overview of the collection of machine-learning methods used to enable a robot to learn from and imitate a teacher. We focus on recent advancements in the field and present an updated taxonomy and characterization of existing methods. We also discuss mature and emerging application areas for LfD and highlight the significant challenges that remain to be overcome both in theory and in practice.
The design, development, and deployment of Ultra-Wideband (UWB) localization systems involves digital and Radio-Frequency (RF) hardware, embedded software, localization algorithms, security and reliability aspects, el...
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The design, development, and deployment of Ultra-Wideband (UWB) localization systems involves digital and Radio-Frequency (RF) hardware, embedded software, localization algorithms, security and reliability aspects, electromagnetics, and others. Design and integration decisions affect the performance of an UWB system, in particular the most important metrics: localization accuracy and position update rate. To facilitate further development of UWB localization systems and to analyze some of the major trade-offs we share our experience in deploying the EPFL UWB-Lite test bed (U-Lite). We describe an approach to numerical simulation modeling that can help in the design and evaluation of UWB localization systems. To validate our approach we show experimental results with one transmitter and one receiver. Our UWB test bed includes a mobile robot platform, so we can study and evaluate the UWB performance trade-offs in real-world conditions.
Ultra-Wideband Impulse Radio (UWB-IR) is a technology that has great potential to solve numerous mobile robotic and asset tracking problems in GPS-denied environments. Our goal is to help software and hardware designe...
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Ultra-Wideband Impulse Radio (UWB-IR) is a technology that has great potential to solve numerous mobile robotic and asset tracking problems in GPS-denied environments. Our goal is to help software and hardware designers in improving the state-of-the-art in UWB-based robotic localization. We developed a test-bed where an UWB transmitter is attached to a mobile robot. By combining the received signals with the robot's position log acquired through the dead-reckoning sensors, we obtain UWB signals which are well referenced with respect to the transmitter-receiver distance and orientation. In addition, we provide a model for every component of the setup. The entire setup allows us to simulate from first principles every aspect of an UWB localization system and then to implement low-level signal processing as well as higher-level modulation and localization techniques. We implement an Automatic Gain Control (AGC) algorithm to demonstrate the rapid proto-typing capabilities of the test-bed. Our work shows how an UWB robotic system and its models can be involved in all phases of the development of a technology that can help robot's navigation, localization and communication algorithms.
This project incorporates modular robots as building blocks for furniture that moves and self-reconfigures. The reconfiguration is done using dynamic connection/disconnection of modules and rotations of the degrees of...
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ISBN:
(纸本)9781424420575
This project incorporates modular robots as building blocks for furniture that moves and self-reconfigures. The reconfiguration is done using dynamic connection/disconnection of modules and rotations of the degrees of freedom. This paper introduces a new approach to self-reconfiguration planning for modular robots based on the graph signature and the graph edit-distance. The method has been tested in simulation on two type of modules: YaMoR and M-TRAN. The simulation results shows interesting features of the approach, namely rapidly finding a near-optimal solution.
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