Tele-Autonomous control involving contact

Object localization and its application in tele-autonomous systems are studied. Two object localization algorithms are presented together with the methods of extracting several important types of object features. The first algorithm is based on line-segment to line-segment matching. Line range sensors are used to extract line-segment features from an object. The extracted features are matched to corresponding model features to compute the location of the object. The inputs of the second algorithm are not limited only to the line features. Featured points (point to point matching) and featured unit direction vectors (vector to vector matching) can also be used as the inputs of the algorithm, and there is no upper limit on the number of the features inputed. The algorithm will allow the use of redundant features to find a better solution. The algorithm uses dual number quaternions to represent the position and orientation of an object and uses the least squares optimization method to find an optimal solution for the object's location. The advantage of using this representation is that the method solves for the location estimation by minimizing a single cost function associated with the sum of the orientation and position errors and thus has a better performance on the estimation, both in accuracy and speed, than that of other similar algorithms. The difficulties when the operator is controlling a remote robot to perform manipulation tasks are also discussed. The main problems facing the operator are time delays on the signal transmission and the uncertainties of the remote environment. How object localization techniques can be used together with other techniques such as predictor display and time desynchronization to help to overcome these difficulties are then discussed

Co-Optimization of Communication, Motion and Sensing in Mobile Robotic Operations

In recent years, there has been considerable interest in wireless sensor networks and networked robotic systems. In order to achieve the full potential of such systems, integrative approaches that design the communication, navigation and sensing aspects of the systems simultaneously are needed. However, most of the existing work in the control and robotic communities uses over-simplified disk models or path-loss-only models to characterize the communication in the network, while most of the work in networkingand communication communities does not fully explore the benefits of motion.This dissertation thus focuses on co-optimizing these three aspects simultaneously in realistic communication environments that experience path loss, shadowing and multi-path fading. We show how to integrate the probabilistic channel prediction framework, which allows the robots to predict the channel quality at unvisited locations, into the co-optimization design. In particular, we consider four different scenarios: 1) robotic routerformation, 2) communication and motion energy co-optimization along a pre-defined trajectory, 3) communication and motion energy co-optimization with trajectory planning, and 4) clustering and path planning strategies for robotic data collection. Our theoretical, simulation and experimental results show that the proposed framework considerably outperforms the cases where the communication, motion and sensing aspects of the system are optimized separately, indicating the necessity of co-optimization. They furthershow the significant benefits of using realistic channel models, as compared to the case of using over-simplified disk models

Editable View Optimized Tone Mapping For Viewing High Dynamic Range Panoramas On Head Mounted Display

Head mounted displays are characterized by relatively low resolution and low dynamic range. These limitations significantly reduce the visual quality of photo-realistic captures on such displays. This thesis presents an interactive view optimized tone mapping technique for viewing large sized high dynamic range panoramas up to 16384 by 8192 on head mounted displays. This technique generates a separate file storing pre-computed view-adjusted mapping function parameters. We define this technique as ToneTexture. The use of a view adjusted tone mapping allows for expansion of the perceived color space available to the end user. This yields an improved visual appearance of both high dynamic range panoramas and low dynamic range panoramas on such displays. Moreover, by providing proper interface to manipulate on ToneTexture, users are allowed to adjust the mapping function as to changing color emphasis. The authors present comparisons of the results produced by ToneTexture technique against widely-used Reinhard tone mapping operator and Filmic tone mapping operator both objectively via a mathematical quality assessment metrics and subjectively through user study. Demonstration systems are available for desktop and head mounted displays such as Oculus Rift and GearVR

An approximation of the ideal scintillation detector line shape with a generalized gamma distribution

An approximation of the real line shape of a scintillation detector with a generalized gamma distribution is proposed. The approximation describes the ideal scintillation line shape better than the conventional normal distribution. Two parameters of the proposed function are uniquely defined by the first two moments of the detector response.Comment: 26 pages, 8 figures, 2 table

TMA Handbook: A Guide to Successful Transportation Management Associations

Matilda Perry - wifehttps://stars.library.ucf.edu/cfm-ch-register-vol21/1483/thumbnail.jp

Contributions to the efficiency and safety of stand-alone DC microgrids

Currently, the distributed generation based on renewable energy sources is mainly DC. Those DC systems are used diverse applications such as airplanes, automobiles, ships, spaceships, computers, servers, telecommunications stations, among others. This thesis considers an isolated DC microgrid architecture composed of a renewable source, an energy storage system, and a DC load. The thesis is aimed at identifying and solving efficiency and safety problems at the source, the DC bus, and the load. During the development of this Thesis, six contributions to the state-of-the-art of DC microgrids were obtained. The first contribution is the mathematical model of a distributed maximum power point platform formed by multiple module-converter sets connected in series, which can be implemented in different programming languages and deployed on multiple platforms to evaluate optimization strategies. The second contribution is a vectorial MPPT algorithm for a distributed photovoltaic system, based in the perturb and observe algorithm. This algorithm provides a satisfactory trade-off between implementation cost and energy production since it uses a single I/V sensor. The third contribution is a reconfiguration algorithm that optimizes the electrical connections of a commercial photovoltaic array, which enables to maximize the energy extraction under arbitrary shading conditions. The fourth and fifth contributions are two control strategies, based on sliding-modes, designed for a charger/discharger DC/DC converter. Those solutions enable to regulate the voltage on the DC-bus of the microgrid to improve the microgrid safety. One of the strategies considers the current of the DC-bus into the sliding surface, which gives a better performance in terms of overshoot and settling time of the DC bus voltage. The final contribution concerns a control strategy, also based on sliding modes, to regulate a point-of-load DC/DC converter. Such a contribution enables to improve the conversion efficiency, and at the same time, to improve the load safety by reducing the current and voltage ripples delivered by the converter. Finally, those contributions improve the electrical efficiency and operational safety of DC microgrids based on renewable sources. The results obtained in this thesis were published in five journals articles and three communications to conferences. From those, three articles were published in Q1 journals, one article was published in Q3 journal, and another one was published in a Colombian journalResumen: Actualmente, la generación distribuida basada en fuentes de energía renovable es principalmente DC. Estos sistemas DC son utilizados en aviones, automóviles, barcos, naves espaciales, computadores, servidores, estaciones de telecomunicaciones, etc. Esta Tesis considera una arquitectura de microrred DC aislada compuesta por una fuente renovable, un sistema de almacenamiento de energía y una carga DC. La tesis tiene como objetivo identificar y solucionar problemas de eficiencia y seguridad de operación en la fuente, en el bus DC y en la carga. Durante el desarrollo de esta Tesis se obtuvieron seis aportes al estado del arte en microrredes DC. La primera contribución es el modelo matemático de una plataforma de seguimiento del punto de máxima potencia formada por múltiples conjuntos panel-convertidor conectados en serie, el cual se puede implementar en diferentes lenguajes de programación y desplegar en múltiples plataformas para evaluar estrategias de optimización. La segunda contribución es un algoritmo MPPT vectorial para un sistema fotovoltaico distribuido, basado en el algoritmo de perturbar y observar. Este algoritmo proporciona una compensación satisfactoria entre el costo de implementación y la producción de energía, ya que utiliza un solo sensor de I/V. La tercera contribución es un algoritmo de reconfiguración que optimiza las conexiones eléctricas de un arreglo de paneles fotovoltaicos comercial, el cual permite maximizar la extracción de energía bajo condiciones arbitrarias de sombreado. La cuarta y quinta contribución son dos estrategias de control, basadas en modos deslizantes, diseñadas para un convertidor DC/DC cargador/descargador. Estas soluciones permiten regular el voltaje del bus DC de la microrred para mejorar la seguridad de su operación. Una de las estrategias considera la corriente del bus DC en la superficie deslizante, lo cual da un mejor desempeño en cuanto al sobreimpulso y el tiempo de establecimiento del voltaje del bus DC. La contribución final es una estrategia de control, también basada en modos deslizantes, para regular un convertidor DC/DC point-of-load. Esta contribución permite mejorar la eficiencia de la conversión y al mismo tiempo mejorar la seguridad operativa de la carga reduciendo el rizado de voltaje y corriente entregado por el convertidor. Finalmente, estas contribuciones mejoran la eficiencia eléctrica y la seguridad operativa de microrredes DC basadas en fuentes de energía renovable. Los resultados obtenidos en esta Tesis fueron publicados en cinco artículo de revista y tres ponencias en conferencias. De estos, tres artículos fueron publicados en revistas clasificadas en Q1, un artículo fue publicado en una revista con clasificación Q3 y otro en una revista colombianaDoctorad

The National Space Science Data Center

An overview is presented of the services offered by the National Space Science Data Center (NSSDC). The NSSDC was established by the National Aeronautics and Space Administration (NASA) over 20 years ago to be the long-term archive for data from its space missions. NSSDC's goal is to provide the research community with data and attendant services in the most efficient, economical, and useful manner possible now and in the future. The organization is dedicated to getting the most scientific value out of NASA's initial investment in its missions. Each service available to scientists through the world is discussed. Also a contact person is identified for each service in case more information in needed

COBE's search for structure in the Big Bang

The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle

Image-Guided Robotic Dental Implantation With Natural-Root-Formed Implants

Dental implantation is now recognized as the standard of the care for tooth replacement. Although many studies show high short term survival rates greater than 95%, long term studies (\u3e 5 years) have shown success rates as low as 41.9%. Reasons affecting the long term success rates might include surgical factors such as limited accuracy of implant placement, lack of spacing controls, and overheating during the placement. In this dissertation, a comprehensive solution for improving the outcome of current dental implantation is presented, which includes computer-aided preoperative planning for better visualization of patient-specific information and automated robotic site-preparation for superior placement and orientation accuracy. Surgical planning is generated using patient-specific three-dimensional (3D) models which are reconstructed from Cone-beam CT images. An innovative image-guided robotic site-preparation system for implants insertion is designed and implemented. The preoperative plan of the implant insertion is transferred into intra-operative operations of the robot using a two-step registration procedure with the help of a Coordinate Measurement Machine (CMM). The natural-root implants mimic the root structure of natural teeth and were proved by Finite Element Method (FEM) to provide superior stress distribution than current cylinder-shape implants. However, due to their complicated geometry, manual site-preparation for these implants cannot be accomplished. Our innovative image-guided robotic implantation system provides the possibility of using this advanced type of implant. Phantom experiments with patient-specific jaw models were performed to evaluate the accuracy of positioning and orientation. Fiducial Registration Error (FRE) values less than 0.20 mm and final Target Registration Error (TRE) values after the two-step registration of 0.36±0.13 mm (N=5) were achieved. Orientation error was 1.99±1.27° (N=14). Robotic milling of the natural-root implant shape with single- and double-root was also tested, and the results proved that their complicated volumes can be removed as designed by the robot. The milling time for single- and double-root shape was 177 s and 1522 s, respectively