10,789 research outputs found

    Online Predictive Optimization Framework for Stochastic Demand-Responsive Transit Services

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    This study develops an online predictive optimization framework for dynamically operating a transit service in an area of crowd movements. The proposed framework integrates demand prediction and supply optimization to periodically redesign the service routes based on recently observed demand. To predict demand for the service, we use Quantile Regression to estimate the marginal distribution of movement counts between each pair of serviced locations. The framework then combines these marginals into a joint demand distribution by constructing a Gaussian copula, which captures the structure of correlation between the marginals. For supply optimization, we devise a linear programming model, which simultaneously determines the route structure and the service frequency according to the predicted demand. Importantly, our framework both preserves the uncertainty structure of future demand and leverages this for robust route optimization, while keeping both components decoupled. We evaluate our framework using a real-world case study of autonomous mobility in a university campus in Denmark. The results show that our framework often obtains the ground truth optimal solution, and can outperform conventional methods for route optimization, which do not leverage full predictive distributions.Comment: 34 pages, 12 figures, 5 table

    Missing Lensed Images and the Galaxy Disk Mass in CXOCY J220132.8-320144

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    The CXOCY J220132.8-320144 system consists of an edge-on spiral galaxy lensing a background quasar into two bright images. Previous efforts to constrain the mass distribution in the galaxy have suggested that at least one additional image must be present (Castander et al. 2006). These extra images may be hidden behind the disk which features a prominent dust lane. We present and analyze Hubble Space Telescope (HST) observations of the system. We do not detect any extra images, but the observations further narrow the observable parameters of the lens system. We explore a range of models to describe the mass distribution in the system and find that a variety of acceptable model fits exist. All plausible models require 2 magnitudes of dust extinction in order to obscure extra images from detection, and some models may require an offset between the center of the galaxy and the center of the dark matter halo of 1 kiloparsec. Currently unobserved images will be detectable by future James Webb Space Telescope (JWST) observations and will provide strict constraints on the fraction of mass in the disk.Comment: 10 pages, 8 figures, 6 tables. Minor changes, version accepted for publication in Ap

    Light trapping within the grooves of 1D diffraction gratings under monochromatic and sunlight illumination

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    The Rayleigh-Modal method is used to calculate the electromagnetic field within the grooves of a perfectly conducting, rectangular-shaped 1D diffraction grating. An \emph{enhancement coefficient} (η\eta) is introduced in order to quantify such an energy concentration. Accordingly, η>\eta >1 means that the amount of electromagnetic energy present within the grooves is larger than that one will have, over the same volume, if the diffraction grating is replaced by a perfectly reflecting mirror. The results in this paper show that η\eta can be as large as several decades at certain, often narrow, ranges of wavelengths. However, it reduces to approximately 20% under sunlight illumination. In this latter case, such values are achieved when the \textit{optical spacing} between the grooves dndn is greater than 500 nm, where dd is the groove spacing and nn is the refractive index of the substance within the grooves. For dndn smaller than 500 nm the enhancement coefficient turns negligibly small.Comment: This paper contains 11 pages and 4 figures, and will be published elsewher

    Design and Development of Inquiry-based Materials for Conducting Observational Astronomy Research at UTRGV

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    The purpose of this work is to develop instructional materials to enhance the expertise of students in conducting observational astronomy research. The designed instructional units aim to provide students with an adequate knowledge of astronomy and hone their skills necessary in conducting observations, collecting and analyzing data including processing of astronomical images. The instructional design is anchored on the ADDIE model (Analyze, Design, Develop, Implement and Evaluate). The phases from ADDIE were used as a framework to accomplish the process of developing the instructional materials. After following the ADDIE, it was possible to define performance goals and tasks which were used to define a general structure of the material, composed of two instructional units: Observational Astronomy and Data Analysis, each one composed of two tasks and several subtasks. Twelve inquiry-based activities were developed following the three phases of the Karplus’ learning cycle. These activities focus on developing specific knowledge of Astronomy and enhancing skills of the students, leading them to do real science at the observatory. In this paper, the development process and pilot-testing of the inquiry-based activities will be presented

    Entity Identification Problem in Big and Open Data

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    Big and Open Data provide great opportunities to businesses to enhance their competitive advantages if utilized properly. However, during past few years’ research in Big and Open Data process, we have encountered big challenge in entity identification reconciliation, when trying to establish accurate relationships between entities from different data sources. In this paper, we present our innovative Intelligent Reconciliation Platform and Virtual Graphs solution that addresses this issue. With this solution, we are able to efficiently extract Big and Open Data from heterogeneous source, and integrate them into a common analysable format. Further enhanced with the Virtual Graphs technology, entity identification reconciliation is processed dynamically to produce more accurate result at system runtime. Moreover, we believe that our technology can be applied to a wide diversity of entity identification problems in several domains, e.g., e- Health, cultural heritage, and company identities in financial world.Ministerio de Ciencia e Innovación TIN2013-46928-C3-3-

    Avaliação da dor pós-operatória.

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    Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Clínica Médica

    Determination of the influence of specific building regulations in smart buildings

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    The automation of domestic services began to be implemented in buildings since the late nineteenth century, and today we are used to terms like ‘intelligent buildings’, ‘digital home’ or ‘domotic buildings’. These concepts tell us about constructions which integrate new technologies in order to improve comfort, optimize energy consumption or enhance the security of users. In conjunction, building regulations have been updated to suit the needs of society and to regulate these new facilities in such structures. However, we are not always sure about how far, from the quantitative or qualitative point of view, legislation should regulate certain aspects of the building activity. Consequently, content analysis is adopted in this research to determine the influence of building regulations in the implementation of new technologies in the construction process. This study includes the analysis of different European regulations, the collection and documentation of such guidelines that have been established and a study of the impact that all of these have had in the way we start thinking an architectural project. The achievements of the research could be explained in terms of the regulatory requirements that must be taken into account in order to achieve a successful implementation of a home automation system, and the key finding has been the confirmation of how the design of smart buildings may be promoted through specific regulatory requirements while other factors, such as the global economic situation, do not seem to affect directly the rate of penetration of home automation in construction

    Improvement of AlGaN/GaN HEMTs Linearity Using Etched-Fin Gate Structure for Ka Band Applications

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    In this paper, AlGaN/GaN high electron mobility transistors (HEMTs) with etched-fin gate structures fabricated to improve device linearity for Ka-band application are reported. Within the proposed study of planar, one-etched-fin, four-etched-fin, and nine-etched-fin devices, which have 50- m, 25- m, 10- m, and 5- m partial gate widths, respectively, the four-etched-fin gate AlGaN/GaN HEMT devices have demonstrated optimized device linearity with respect to the extrinsic transconductance (Gm) value, the output third order intercept point (OIP3), and the thirdorder intermodulation output power (IMD3) level. The IMD3 is improved by 7 dB at 30 GHz for the 4 50 m HEMT device. The OIP3 is found to reach a maximum value of 36.43 dBm with the four-etched-fin device, which exhibits high potential for the advancement of wireless power amplifier components for Ka band applications.Center for the Semiconductor Technology ResearchFeatured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in TaiwanMinistry of Science and Technology, Taiwan, under Grants NSTC 111-2218- E-A49-021NSTC 111-2634-F-A49-008NSTC 111-2221-E-A49 -173 -MY3NSTC 112-2622-8-A49 -013 –S

    Fiber polytopes for the projections between cyclic polytopes

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    The cyclic polytope C(n,d)C(n,d) is the convex hull of any nn points on the moment curve (t,t2,...,td):t∈R{(t,t^2,...,t^d):t \in \reals} in Rd\reals^d. For d′>dd' >d, we consider the fiber polytope (in the sense of Billera and Sturmfels) associated to the natural projection of cyclic polytopes π:C(n,d′)→C(n,d)\pi: C(n,d') \to C(n,d) which "forgets" the last d′−dd'-d coordinates. It is known that this fiber polytope has face lattice indexed by the coherent polytopal subdivisions of C(n,d)C(n,d) which are induced by the map π\pi. Our main result characterizes the triples (n,d,d′)(n,d,d') for which the fiber polytope is canonical in either of the following two senses: - all polytopal subdivisions induced by π\pi are coherent, - the structure of the fiber polytope does not depend upon the choice of points on the moment curve. We also discuss a new instance with a positive answer to the Generalized Baues Problem, namely that of a projection π:P→Q\pi:P\to Q where QQ has only regular subdivisions and PP has two more vertices than its dimension.Comment: 28 pages with 1 postscript figur
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