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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Active Sensing for Collaborative Localization in Swarm Robotics

Yang, Shengsong 26 May 2020 (has links)
Localization is one of the most important capabilities of mobile robots. Thanks to the fast development of embedded computing hardware in recent years, many localization solutions, such as simultaneous localization and mapping (SLAM), have been vastly investigated. However, popular localization solutions rely heavily on the working environment and are not applicable to scenarios such as search and rescue in the wild, where the working environment is not accessible before the localization operation or where the environment lacks information on features and textures. The thesis thus proposes a design for an innovative localization sensor and a collaborative pose estimation scheme using the localization sensor in order to alleviate the reliance on information from the environment, while providing reliable and accurate pose estimates for mobile robots. The proposed collaborative pose estimation scheme is comprised of individual and collaborative landmark position estimation, localization sensor inter-calibration, and collaborative sensor pose estimation, among which the inter-calibration process ensures that the sensor provides capability to also estimate orientations. In the collaborative scheme, multiple instances of the proposed sensor collaborate to estimate their respective poses by measuring the relative distance and angle among them, where the measurement errors are characterized as Gaussian white noise. Two instances of the proposed localization sensor are implemented, and the collaborative scheme is tested with the instances in the thesis. Both sensor instances reliably and accurately estimate the position of a stationary landmark, and it is demonstrated that the collaboratively estimated position estimate is more accurate than its individual counterpart. Additionally, the two instances also demonstrate their ability to track and estimate the position of a moving landmark. Lastly, the inter-calibration is experimentally validated with the instances with satisfactory performance. The experimental results presented in this work confirm the feasibility and usability of the proposed collaborative pose estimation scheme in a wide range of robotic applications.
52

High Resolution Robust GPS-free Localization for Wireless Sensor Networks and its Applications

Mirza, Mohammed 12 December 2011 (has links)
In this thesis we investigate the problem of robustness and scalability w.r.t. estimating the position of randomly deployed motes/nodes of a Wireless Sensor Network (WSN) without the help of Global Positioning System (GPS) devices. We propose a few applications of range independent localization algorithms that allow the sensors to actively determine their location with high resolution without increasing the complexity of the hardware or any additional device setup. In our first application we try to present a localized and centralized cooperative spectrum sensing using RF sensor networks. This scheme collaboratively sense the spectrum and localize the whole network efficiently and with less difficulty. In second application we try to focus on how efficiently we can localize the nodes, to detect underwater threats, without the use of beacons. In third application we try to focus on 3-Dimensional localization for LTE systems. Our performance evaluation shows that these schemes lead to a significant improvement in localization accuracy compared to the state-of-art range independent localization schemes, without requiring GPS support.
53

Food re-network: A reduced food chain to address food insecurity

January 2018 (has links)
A problem facing over 41 million Americans today is food insecurity [15]. The root of this problem lies in the inequitable distribution of healthy and affordable food to low-income neighborhoods because of an industry that is profit-based and lacks a physical connection between the production and consumption of food. Even though 82 percent of consumers live in cities, food is produced in rural areas and transported several times before arriving in the consumer’s hands [03]. Grocery stores are profit-based and invest in locations with higher buying power, resulting in a lack of access to food in low-income areas. In order to create a new attitude around providing food for underserved neighborhoods, the design of a new, highly-visible, sector of food processing must be independent from the existing profit-based food industry. This consolidated and localized system should not only serve as an equitable distributor of food but also as the beacon of security and example of efficiency that the contemporary food system lacks. This thesis explores the utilization of urban resources, in the physical reconfiguration and consolidation of the elements of the contemporary food chain. The resulting solution aims to create an efficient, self-sustaining, and accessible source of nutrition in low-income neighborhoods. / 0 / SPK / specialcollections@tulane.edu
54

Řízení čtyřkolového mobilního robotu / 4 Wheel mobile robot control

Deďo, Michal January 2011 (has links)
The purpose of this thesis is to design and implement four-wheel mobile robot control which will be used in future in the field of mapping and localization. Concretely, it will be a design of drive control with microcontrollers Xmega, which will also process the signals of the sensors. Communication with the PC will ensure the BlueTooth module. In view of the future use of the robot, there will be designed and carried out modifications of the mechanical part. Correctness and functionality of all parts of the robot will be verified by carrying out basic movements.
55

Postranslační modifikace ovlivňující funkci jaderného lokalizačního signálu / Posttranslational modifications affecting function of nuclear localization signal

Šebrle, Erik January 2016 (has links)
Transport of proteins to the nucleus through a nuclear envelope is controlled mostly via nuclear localization signal (NLS). Nuclear localization signal is rich in positively charged amino acids arginine and lysine. It was observed that activity of this NLS could be regulated through a phosphorylation of serine in its close proximity. Either a phosphorylation of serine or phosphomimetic changes of these "presequences" could represent an important mechanism regulating a localization of protein in cells in relation to a cellular activation. In our laboratory was identified protein - Fragile X mental retardation syndrome 1 neighbor (Fmr1nb), whose cellular localization could be driven by this posttranslational modification.
56

Machine Learning Enabled-Localization in 5G and LTE Using Image Classification and Deep Learning

Mukhtar, Hind 23 July 2021 (has links)
Demand for localization has been growing due to the increase in location-based services and high bandwidth applications requiring precise localization of users to improve resource management and beam forming. Outdoor localization has been traditionally done through Global Positioning System (GPS), however it’s performance degrades in urban settings due to obstruction and multi-path effects, creating the need for better localization techniques. This thesis proposes a technique using a cascaded approach composed of image classification and deep learning using LIDAR or satellite images and Channel State In-formation (CSI) data from base stations to predict the location of moving vehicles and users outdoors. The algorithm’s performance is assessed using 3 different datasets. The first two use simulated data in the Milli-meter Wave (mmWave) band and lidar images that are collected from the neighbourhood of Rosslyn in Arlington, Virginia. The results show an improvement in localization accuracy as a result of the hierarchical architecture, with a Mean Absolute Error (MAE) of 6.55m for the proposed technique in comparison to a MAE of 9.82m using one Convolutional Neural Network (CNN). The third dataset uses measurements from an LTE mobile communication system along with satellite images that take place at the University of Denmark. The results achieve a MAE of 9.45 m fort he heirchichal approach in comparison to a MAE of 15.74 m for one Feed-Forward Neural Network (FFNN).
57

Indoor Localization Using Magnetic Fields

Pathapati Subbu, Kalyan Sasidhar 12 1900 (has links)
Indoor localization consists of locating oneself inside new buildings. GPS does not work indoors due to multipath reflection and signal blockage. WiFi based systems assume ubiquitous availability and infrastructure based systems require expensive installations, hence making indoor localization an open problem. This dissertation consists of solving the problem of indoor localization by thoroughly exploiting the indoor ambient magnetic fields comprising mainly of disturbances termed as anomalies in the Earth’s magnetic field caused by pillars, doors and elevators in hallways which are ferromagnetic in nature. By observing uniqueness in magnetic signatures collected from different campus buildings, the work presents the identification of landmarks and guideposts from these signatures and further develops magnetic maps of buildings - all of which can be used to locate and navigate people indoors. To understand the reason behind these anomalies, first a comparison between the measured and model generated Earth’s magnetic field is made, verifying the presence of a constant field without any disturbances. Then by modeling the magnetic field behavior of different pillars such as steel reinforced concrete, solid steel, and other structures like doors and elevators, the interaction of the Earth’s field with the ferromagnetic fields is described thereby explaining the causes of the uniqueness in the signatures that comprise these disturbances. Next, by employing the dynamic time warping algorithm to account for time differences in signatures obtained from users walking at different speeds, an indoor localization application capable of classifying locations using the magnetic signatures is developed solely on the smart phone. The application required users to walk short distances of 3-6 m anywhere in hallway to be located with accuracies of 80-99%. The classification framework was further validated with over 90% accuracies using model generated magnetic signatures representing hallways with different kinds of pillars, doors and elevators. All in all, this dissertation contributes the following: 1) provides a framework for understanding the presence of ambient magnetic fields indoors and utilizing them to solve the indoor localization problem; 2) develops an application that is independent of the user and the smart phones and 3) requires no other infrastructure since it is deployed on a device that encapsulates the sensing, computing and inferring functionalities, thereby making it a novel contribution to the mobile and pervasive computing domain.
58

Dual encoding in memory : evidence from temporal-lobe lesions in man

Jaccarino, Gina Ellen. January 1975 (has links)
No description available.
59

Effect of hippocampal stimulation on Feeding in the rat.

Milgram, N. W. (Norton William) January 1968 (has links)
No description available.
60

Organization of eating and drinking sites in the lateral hypothalamus.

Wise, Roy A. January 1968 (has links)
No description available.

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