1,249 research outputs found

    Multi-sensor fusion on mobile platforms

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    An important goal for many mobile platforms---terrestrial, aquatic, or airborne---is reliable, accurate, and on-time sensing of the world around them. The PRIME Lab has been investigating multi-sensor fusion for many applications, including explosive hazard detection and infrastructure inspection, from terrestrial vehicles and unmanned aerial vehicles (UAVs). New developments in multi-sensor fusion using radars, imaging sensors, and LIDAR will be discussed that encompass advancements from novel signal processing approaches for mobile ground-penetrating radar to more theoretical approaches for optimal fusion of measurements from multi-modal sensors. This talk will explore the area of sensor-fusion both from a practical, application-focused standpoint and also from a theoretical learning-theory approach to information fusion.https://digitalcommons.mtu.edu/techtalks/1027/thumbnail.jp

    Clustering in relational data and ontologies

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    Title from PDF of title page (University of Missouri--Columbia, viewed on August 20, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. James M. Keller.Vita.Ph. D. University of Missouri--Columbia 2010.This dissertation studies the problem of clustering objects represented by relational data. This is a pertinent problem as many real-world data sets can only be represented by relational data for which object-based clustering algorithms are not designed. Relational data are encountered in many fields including biology, management, industrial engineering, and social sciences. Unlike numerical object data, which are represented by a set of feature values (e.g. height, weight, shoe size) of an object, relational object data are the numerical values of (dis) similarity between objects. For this reason, conventional cluster analysis methods such as k-means and fuzzy c-means cannot be used directly with relational data. I focus on three main problems of cluster analysis of relational data: (i) tendency prior to clustering -- how many clusters are there?; (ii) partitioning of objects -- which objects belong to which cluster?; and (iii) validity of the resultant clusters -- are the partitions \good"?Analyses are included in this dissertation that prove that the Visual Assessment of cluster Tendency (VAT) algorithm has a direct relation to single-linkage hierarchical clustering and Dunn's cluster validity index. These analyses are important to the development of two novel clustering algorithms, CLODD-CLustering in Ordered Dissimilarity Data and ReSL-Rectangular Single-Linkage clustering. Last, this dissertation addresses clustering in ontologies; examples include the Gene Ontology, the MeSH ontology, patient medical records, and web documents. I apply an extension to the Self-Organizing Map (SOM) to produce a new algorithm, the OSOM-Ontological Self-Organizing Map. OSOM provides visualization and linguistic summarization of ontology-based data.Includes bibliographical references

    A Possible Explanation of Concrete Pop-Outs

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    This report summarizes several years of research relating to damage to concrete and aggregates undergoing freezing and thawing. Basic principles involving freezing and attendant pressures are considered. Application of these principles to the evaluation of concrete was accomplished in experiments on concrete having low and high air contents. Freeze-thaw characteristics of saturated aggregates relative to physical properties such as porosity, absorption, and bulk specific gravity were studied by submerging individual particles in pre-chilled mercury. Pressures associated with pop-outs in concrete were monitored and are presented along with accompanying theoretical considerations

    Fatigue Analysis from Strain Gage Data and Probability Analysis

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    The Central Bridge over the Ohio River between Newport, Kentucky, and Cincinnati, Ohio, was completed in 1891 and in 1972-73 was considered to be in danger of fatigue failure. A series of investigations were undertaken to determine the likelihood of failure and to estimate the time of probable failure. During the investigation, a methodology was developed to determine fatigue damage from a probability analysis of traffic data by reconstituting or synthesizing the load (traffic) history of bridges. Strain gage data obtained with Prewitt scratch gages and SR-4 resistivity gages were used to evaluate fatigue damage incurred by the Central Bridge

    Freeze-and-Thaw of Concretes and Aggregates

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    This report summarizes several years of research relating to damage to concrete and aggregates undergoing freezing and thawing. Basic principles involving freezing and attendant pressures are considered. Application of these principles to the evaluation of concrete was accomplished in experiments on concrete having low and high air contents. The effects of air entrainment upon freeze-thaw resistance were demonstrated. Freeze-thaw characteristics of saturated aggregates relative to physical properties such as porosity, absorption, and bulk specific gravity were studied by submerging individual particles in pre-chilled mercury. Pressures associated with popouts in concrete were monitored and are presented along with accompanying theoretical considerations

    Bridges: Synthesis of Load Histories and Analysis of Fatigue

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    Repeated stressing of metals above certain limits induces inter- and intra-crystalline dislocations and cleavages and eventually cracks which propagate to failure. Some authorities consider crack propagation to be a separate and discrete stage in the failure process. The internal damage is insidiously cumulative and irreversible. This phenomenon was recognized as early as 1829 and was termed fatigue as early as 1839(1). From the beginning of fatigue testing (Wohler, 1858-1870), results have been reported as S-N, S-log N, or log S-log N curves, where N is the number of repetitions of stress S. From a structural design point of view, the purpose of fatigue testing then was to find the endurance or fatigue limit (i.e., fEL) and so to establish the design or working stress (for many steels, fEL came to be regarded as 55 percent of fy, the yield stress, or 46 percent of fu, the ultimate strength)

    Landslides in Kentucky

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    The reoccurrence of certain features of landslides in Kentucky suggests that the difficulties in the State can be readily classified. Because of this repetitive nature, one can be alerted to the possibility of slides in certain situations early in the planning and design stages of the facility to be constructed. Thus, the traveling public might be spared the inconvenience illustrated in Figure 1. Enough cannot be said concerning the necessity for having adequate soils and geological information concerning possible routes for highway locations, and a review of a number of landslides in Kentucky suggests that there are certain troublesome geologic formations

    Some Effects of Fabrication Practices on the Strength Characteristics of Reinforced Concrete Culvert Pipe

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    Underground conduits have been used for hundreds of years for drainage and water supply purposes. With the advent of railway and auto-mobile transportation, the use of underground conduits for drainage purposes beneath the roadways increased greatly. It soon became apparent that there was a definite need for knowledge concerning the manufacture, installation, and field behavior of pipe culverts. Accordingly, in the first half of the century, much attention and research has been directed toward the development and establishment of acceptable techniques and specifications fot the manufacture and installation of pipe culverts. This work has been accomplished by many individuals and organizations
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