130 research outputs found

    Efficient Structure and Motion: Path Planning, Uncertainty and Sparsity

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    This thesis explores methods for solving the structure-and-motion problem in computer vision, the recovery of three-dimensional data from a series of two-dimensional image projections. The first paper investigates an alternative state space parametrization for use with the Kalman filter approach to simultaneous localization and mapping, and shows it has superior convergence properties compared with the state-of-the-art. The second paper presents a continuous optimization method for mobile robot path planning, designed to minimize the uncertainty of the geometry reconstructed from images taken by the robot. Similar concepts are applied in the third paper to the problem of sequential 3D reconstruction from unordered image sequences, resulting in increased robustness, accuracy and a reduced need for costly bundle adjustment operations. In the final paper, a method for efficient solution of bundle adjustment problems based on a junction tree decomposition is presented, exploiting the sparseness patterns in typical structure-and-motion input data

    Institutions and Indirectness in Intellectual Property

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    Institutions are important to intellectual property. Information is a major subject of exchange, and the special challenges of contracting over information have long been at the heart of economic theories of contracting. Exchanges involving information are difficult because a buyer will be reluctant to make a purchase without knowing what he is buying, but once the seller reveals the information, the buyer will no longer need to pay for it. Contractors can also face challenges from asymmetric information, and some of the limits on people’s ability to contract stem from the problems of incomplete information

    Institutions and Indirectness in Intellectual Property

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    Air transportation schedule planning

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    Cover titleJune 1972Includes bibliographical referencesOne of the routing and scheduling problems faced by an airline is to configure a route network. It seeks to answer the following two questions: First, should scheduled service be provided for a city pair market? Second, if market entry is warranted, should the city pair be served by a non-stop, multi-stop, or connect routing? A profit maximizing airline, in trying to answer these questions, has to abide by the route regulations imposed by the Civil Aeronautics Board. The airline has to take into account the inter carrier route competition. It has to recognize that its share of the passenger demand is a function of the level of service offered, and that passengers usually want to reach their destination in the most convenient routing for themselves. An optimization model is formulated for the route network configuration problem. Because of the huge combinatorial dimensionality inherent in the problem, a special solution method has to be devised. Only a handful of the most promising, feasible route candidates are identified at a time. An optimal choice is immediately made out of the few candidates. These route candidates are generated "as needed" by graph theoretic schemes, while route selection is performed by solving an integer program characterized by an ill-behaved objective function. At each generation/selection step, route network improvement is made by the optimal selection of the route candidate (i) to add to an existing network, (ii) to replace an unprofitable route, or simply (iii) to be deleted from the route network. The solution algorithm is based on the method of successive approximation in dynamic programming. Primal feasibility is maintained at all times. If the algorithm is stopped prematurely, due to limited computational resources, an improved (but not necessarily optimal) solution is always available. A 40-routine computer software package for the algorithm has been developed. It was successfully used to analyze a case study from American Airlines. Our limited computational experience showed that execution time is at least seven times faster than a comparable algorithm.Sponsored in part by Slater Funds for Flight Transportation and the NASA research grant -- Joint University Research Program for Air Transportation Needs, and a fellowship from the M.I.T.-Harvard Joint Center for Urban Studies

    All-Silicon-Based Photonic Quantum Random Number Generators

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    Random numbers are fundamental elements in different fields of science and technology such as computer simulation like Monte Carlo-method simulation, statistical sampling, cryptography, games and gambling, and other areas where unpredictable results are necessary. Random number generators (RNG) are generally classified as “pseudo”-random number generators (PRNG) and "truly" random number generators (TRNG). Pseudo random numbers are generated by computer algorithms with a (random) seed and a specific formula. The random numbers produced in this way (with a small degree of unpredictability) are good enough for some applications such as computer simulation. However, for some other applications like cryptography they are not completely reliable. When the seed is revealed, the entire sequence of numbers can be produced. The periodicity is also an undesirable property of PRNGs that can be disregarded for most practical purposes if the sequence recurs after a very long period. However, the predictability still remains a tremendous disadvantage of this type of generators. Truly random numbers, on the other hand, can be generated through physical sources of randomness like flipping a coin. However, the approaches exploiting classical motion and classical physics to generate random numbers possess a deterministic nature that is transferred to the generated random numbers. The best solution is to benefit from the assets of indeterminacy and randomness in quantum physics. Based on the quantum theory, the properties of a particle cannot be determined with arbitrary precision until a measurement is carried out. The result of a measurement, therefore, remains unpredictable and random. Optical phenomena including photons as the quanta of light have various random, non-deterministic properties. These properties include the polarization of the photons, the exact number of photons impinging a detector and the photon arrival times. Such intrinsically random properties can be exploited to generate truly random numbers. Silicon (Si) is considered as an interesting material in integrated optics. Microelectronic chips made from Si are cheap and easy to mass-fabricate, and can be densely integrated. Si integrated optical chips, that can generate, modulate, process and detect light signals, exploit the benefits of Si while also being fully compatible with electronic. Since many electronic components can be integrated into a single chip, Si is an ideal candidate for the production of small, powerful devices. By complementary metal-oxide-semiconductor (CMOS) technology, the fabrication of compact and mass manufacturable devices with integrated components on the Si platform is achievable. In this thesis we aim to model, study and fabricate a compact photonic quantum random number generator (QRNG) on the Si platform that is able to generate high quality, "truly" random numbers. The proposed QRNG is based on a Si light source (LED) coupled with a Si single photon avalanche diode (SPAD) or an array of SPADs which is called Si photomultiplier (SiPM). Various implementations of QRNG have been developed reaching an ultimate geometry where both the source and the SPAD are integrated on the same chip and fabricated by the same process. This activity was performed within the project SiQuro—on Si chip quantum optics for quantum computing and secure communications—which aims to bring the quantum world into integrated photonics. By using the same successful paradigm of microelectronics—the study and design of very small electronic devices typically made from semiconductor materials—, the vision is to have low cost and mass manufacturable integrated quantum photonic circuits for a variety of different applications in quantum computing, measure, sensing, secure communications and services. The Si platform permits, in a natural way, the integration of quantum photonics with electronics. Two methodologies are presented to generate random numbers: one is based on photon counting measurements and another one is based on photon arrival time measurements. The latter is robust, masks all the drawbacks of afterpulsing, dead time and jitter of the Si SPAD and is effectively insensitive to ageing of the LED and to its emission drifts related to temperature variations. The raw data pass all the statistical tests in national institute of standards and technology (NIST) tests suite and TestU01 Alphabit battery without a post processing algorithm. The maximum demonstrated bit rate is 1.68 Mbps with the efficiency of 4-bits per detected photon. In order to realize a small, portable QRNG, we have produced a compact configuration consisting of a Si nanocrystals (Si-NCs) LED and a SiPM. All the statistical test in the NIST tests suite pass for the raw data with the maximum bit rate of 0.5 Mbps. We also prepared and studied a compact chip consisting of a Si-NCs LED and an array of detectors. An integrated chip, composed of Si p+/n junction working in avalanche region and a Si SPAD, was produced as well. High quality random numbers are produced through our robust methodology at the highest speed of 100 kcps. Integration of the source of entropy and the detector on a single chip is an efficient way to produce a compact RNG. A small RNG is an essential element to guarantee the security of our everyday life. It can be readily implemented into electronic devices for data encryption. The idea of "utmost security" would no longer be limited to particular organs owning sensitive information. It would be accessible to every one in everyday life

    Brigham-Kanner Property Rights Journal, Volume 10

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    Where Theory Meets Practice October 1-2, 2020 Panel 1: Where Theory Meets Practice: A Tribute to Henry E. Smith Panel 2: The Housing Crisis Lunch Roundtable: Emerging Issues in Takings and Eminent Domain Law Panel 3: The Reach of Government\u27s Confiscatory Powers Over Exigencies and Emergencies Panel 4: The Risk of Unjust Compensationhttps://scholarship.law.wm.edu/propertyjournal/1010/thumbnail.jp
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