247 research outputs found

    A Bio-Wicking System to Mitigate Capillary Water in Base Course

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    Water within pavement layers is the major cause of pavement deteriorations. High water content results in significant reduction in soil’s resilient behavior and increase in permanent deformation. Conventional drainage systems can only drain gravity water but not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. This bio-wicking system aims at resolving the potential issues that the original design may encounter: (1) H2Ri ultraviolet degradation, (2) H2Ri mechanical failure, (3) loss of drainage function under high suction, and (4) clogging and salt concentration. Both elemental level and full-scale test results indicated that the bio-wicking system is more effective in draining capillary water within the base courses compared with original design, in which the geotextile is directly exposed to the open air. However, a good drainage condition is required for the bio-wicking system to maintain its drainage efficiency. Accumulation of excess water will result in water re-entering the road embankment. Moreover, grass root and geotextile share the same working mechanism in transporting water. In the proposed bio-wicking system, the relatively smaller channels in the grass roots further ensures water moving from H2Ri geotextile, transporting through the stems of grass, and eventually evapo-transpiring into the air at the leaf-air interfaces. In sum, the bio-wicking system seemed to successfully address the concerns in the preliminary design and is a more efficient system to dehydrate the road embankment under unsaturated conditions.TenCate Geosynthetic

    Higher rank (q,t)(q,t)-Catalan polynomials, affine Springer fibers, and a finite Rational Shuffle Theorem

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    We introduce the higher rank (q,t)(q,t)-Catalan polynomials and prove they equal truncations of the Hikita polynomial to a finite number of variables. Using affine compositions and a certain standardization map, we define a dinv statistic on rank rr semistandard (m,n)(m,n)-parking functions and prove codinv counts the dimension of an affine space in an affine paving of a parabolic affine Springer fiber. Combining these results, we give a finite analogue of the Rational Shuffle Theorem in the context of double affine Hecke algebras. Lastly, we also give a Bizley-type formula for the higher rank Catalan numbers in the non-coprime case.Comment: 38 pages, 6 figures. Comments welcome

    Frequency Domain Decomposition of Digital Video Containing Multiple Moving Objects

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    Motion estimation has been dominated by time domain methods such as block matching and optical flow. However, these methods have problems with multiple moving objects in the video scene, moving backgrounds, noise, and fractional pixel/frame motion. This dissertation proposes a frequency domain method (FDM) that solves these problems. The methodology introduced here addresses multiple moving objects, with or without a moving background, 3-D frequency domain decomposition of digital video as the sum of locally translational (or, in the case of background, a globally translational motion), with high noise rejection. Additionally, via a version of the chirp-Z, fractional pixel/frame motion detection and quantification is accomplished. Furthermore, images of particular moving objects can be extracted and reconstructed from the frequency domain. Finally, this method can be integrated into a larger system to support motion analysis. The method presented here has been tested with synthetic data, realistic, high fidelity simulations, and actual data from established video archives to verify the claims made for the method, all presented here. In addition, a convincing comparison with an up-and-coming spatial domain method, incremental principal component pursuit (iPCP), is presented, where the FDM performs markedly better than its competition

    Settings for collective control : design and programmatic propositions for the reinforcement of resident serive capacity in low-income housing developments/

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    Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Bibliography: leaves 179-182.Major "redevelopment" projects are being planned and undertaken by the Boston Housing Authority to reverse the "cycle of deterioration" threatening the existence of most of Boston's largest and oldest public housing developments. This thesis focuses on the West Broadway and Franklin Field Developments which have together been earmarked by State and Federal governments to receive a total of nearly $50 million for "redevelopment" programs. The central problem concerning this thesis is the lack of design and programmatic principles with which to apply not only the information generated by recent housing research but that of the collective service needs, capacities and responsibilities existing for present and future communities in public housing. The physical and social contexts as the West Broadway Development are examined as the bases for design and programmatic "propositions" generated to define the following "organizational elements": circulation hierarchy, residential clustering, service supports and facilities, and service facility clusters. The propositions are intended to provide explicit definition to existing and potential levels of resident organization and collective service responsibilities, levels which are seen as essential where residents are destined to become increasingly more involved in the management, maintenance and security of their non-private living environment. The "propositions" are then applied to the Franklin Field development to evaluate their generalizability outside a specific context. The application served both to illuminate a number of new opportunities for and constraints upon the use of the propositions and to distinguish general 'service zones' which represent relatively distinct sets of security and maintenance problems and associations between household clusters. A compilation of relevant excerpts from recent housing research literature is presented in the Appendices to supplement the analyses, and propositions forwarded for each of the main "organizational elements" as highlighted in the main chapters.by Rad Collier Acton.M.Arch

    \u3ci\u3eThe Conference Proceedings of the 1998 Air Transport Research Group (ATRG) of the WCTR Society, Volume 1 \u3c/i\u3e

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    UNOAI Report 98-6https://digitalcommons.unomaha.edu/facultybooks/1154/thumbnail.jp

    Layered graphical models for tracking partially-occluded moving objects in video (PhD thesis)

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    Tracking multiple targets using fixed cameras with non-overlapping views is a challenging problem. One of the challenges is predicting and tracking through occlusions caused by other targets or by fixed objects in the scene. Considerable effort has been devoted toward developing appearance models that are robust to partial occlusions, tracking algorithms that cope with short-term loss of observations, and algorithms that learn static occlusion maps. In this thesis we consider scenarios where it is impossible to learn a static occlusion map. This is often the case when the scene consists of both people and large objects whose position is not permanently fixed. These objects may enter, leave or relocate within the scene during a short time span. We call such objects "relocatable objects" or "relocatable occluders." We develop a representation for scenes containing relocatable objects that can cause partial occlusions of people in a camera's field of view. In many practical applications, relocatable objects tend to appear often; therefore, models for them can be learned off-line and stored in a database. We formulate an occluder-centric representation, called a graphical model layer, where a person's motion in the ground plane is defined as a first-order Markov process on activity zones, while image evidence is aggregated in 2D observation regions that are depth-ordered with respect to the occlusion mask of the relocatable object. We represent real-world scenes as a composition of depth-ordered, interacting graphical model layers, and account for image evidence in a way that handles mutual overlap of the observation regions and their occlusions by the relocatable objects. These layers interact: proximate ground plane zones of different model instances are linked to allow a person to move between the layers, and image evidence is shared between the observation regions of these models. We demonstrate our formulation in tracking low-resolution, partially-occluded pedestrians in the vicinity of parked vehicles. In these scenarios some tracking formulations that rely on part-based person detectors may fail completely. Our pedestrian tracker fares well and compares favorably with the state-of-the-art pedestrian detectors---lowering false positives by twenty-nine percent and false negatives by forty-two percent---and a deformable-contour--based tracker

    Flow Measurements Using Particle Image Velocimetry in the Ultra Compact Combustor

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    Velocity measurements were performed using the Particle Image Velocimetry (PIV) technique on the Ultra Compact Combustor (UCC) test rig at the Air Force Institute of Technology (AFIT). Velocity patterns and time-averaged turbulence statistics were calculated for data taken with the UCC burning hydrogen fuel in the straight cavity vane and curved cavity vane configurations. The equivalence ratio was varied from 0.7 to 1.5, while the ratio of cavity air to main air was varied from 5% to 20% in testing performed on the straight vane configuration. Spanwise velocity was observed to decrease linearly with distance from the cavity vane over the width of the main channel, but spanwise turbulence intensity penetrated into less than 50% of the main channel for all conditions except the most fuel rich (φ=1.5) suggesting more rich conditions may prove better for both mixing and operability. A velocity effect study was performed in the curved and straight cavity vane configuration by increasing the flow rates, but holding the equivalence ratio and ratio of cavity to main air flow rates constant. Relative turbulence intensities were found to be independent of overall flow velocity in the straight configuration, while a negative correlation was observed in the curved configuration. Overall turbulence intensity levels were measured at 15% and 21% of the main channel velocity for the straight and curved configurations respectively. The highest average turbulence intensities were observed near the cross-flow of the cavity vane, and peak turbulence was observed just over the Radial Vane Cavity (RVC). The RVC was observed to generate flow rotation. Peak vorticity was observed farthest from the cavity vane suggesting the angle of the RVC is effective in generating increasing flow rotation with streamwise velocity
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