6,612 research outputs found
P02.20. Mindfulness based tinnitus stress reduction (MBTSR) pilot study: a symptom perception shift program
Social and Physical Planning for the Elimination of Urban Poverty
The provision of public facilities is also a traditional planning emphasis, dating back to the days when the planner was an ally of the reformers who were fighting for the establishment of these facilities. Out of this has come the belief that public facilities are crucial agencies in people\u27s lives, that up-to-date facilities and programs will encourage intensive use of them and that this in turn will help significantly in achieving the aims of guided mobility planning.
Despite the intensity of the planner\u27s belief in neighborhood and public facility use, there is no evidence that these two planning concepts are as important to low income people as they are to planners. Consequently, it is fair to ask whether such concepts are as crucial to the elimination of urban poverty and deprivation as is signified by their appearance in some guided mobility plans. The answer to this question requires a brief discussion of the nature of contemporary urban poverty
Access regulation and the transition from copper to fiber networks in telecoms
In this paper we study the impact of different forms of access obligations on firms' incentives to migrate from the legacy copper network to ultra-fast broadband infrastructures. We analyze three different kinds of regulatory interventions: geographical regulation of access to copper networks-where access prices are differentiated depending on whether or not an alternative fiber network has been deployed; access obligations on fiber networks and its interplay with wholesale copper prices; and, finally, a mandatory switch-off of the legacy copper network-to foster the transition to the higher quality fiber networks. Trading-off the different static and dynamic goals, the paper provides guidelines and suggestions for policy makers' decision
Functional Aspects Of The Evolution Of Frog Tongues
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137442/1/evo00952.pd
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Efficient Computer Simulation of Polymer Conformation. I. Geometric Properties of the Hard-Sphere Model
A system of efficient computer programs has been developed for simulating the conformations of macromolecules. The conformation of an individual polymer is defined as a point in conformation space, whose mutually orthogonal axes represent the successive dihedral angles of the backbone chain. The statistical-mechanical average of any property is obtained as the usual configuration integral over this space. A Monte Carlo method for estimating averages is used because of the impossibility of direct numerical integration. Monte Carlo corresponds to the execution of a Markoffian random walk of a representative point through the conformation space. Unlike many previous Monte Carlo studies of polymers, which sample conformation space indiscriminately, importance sampling increases efficiency because selection of new polymers is biased to reflect their Boltzmann probabilities in the canonical ensemble, leading to reduction of sampling variance and hence to greater accuracy! in given computing time. The simulation is illustrated in detail. Overall running time is proportional to n^(5/4), where n is the chain length. Results are presented for a hard-sphere linear polymer of n atoms, with free dihedral rotation, with n = 20-298. The fraction of polymers accepted in the importance sampling scheme, fA, is fit to a Fisher-Sykes attrition relation, giving an effective attrition constant of zero. fA is itself an upper bound to the partition function, Q, relative to the unrestricted walk. The mean-squared end-to-end distance and radius of gyration exhibit the expected exponential dependence, but with exponent for the radius of gyration significantly greater than that of the end-to-end distance. The 90% confidence limits calculated for both exponents did not include either 6/5 or 4/3, the lattice and zero-order perturbation values, respectively. A self-correcting scheme for generating coordinates free of roundoff error is given in an Appendix
Structural optimization incorporating centrifugal and Coriolis effects
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76768/1/AIAA-1989-1310-955.pd
Estimation of electrical resistivity of conductive materials of random shapes
Introduction. Electrical resistivity is an important material characteristic in the field of electrical engineering and material science. There are several methods that can be used to measure resistance, like the 4-wire method which relates the resistance to a voltage drop at a given current flow, but to define the resistivity from the resistance value requires an analytical expression for the given system which requires a sufficient mathematical apparatus for describing complicated shapes. Therefore we use finite element method computations to compute the resistivity of a metal material. This approach has been already used for different materials like concrete and aluminum in the past. We then compare this method with an analytical expression that due to intuition could approximate the solution sufficiently. After that, the same material is used again to test the electrical isotropy of the sample. Novelty. A method is developed by combining the results of experimental studies and the results of mathematical modelling of the process of determining the electrical conductivity of metals. The goal is to describe and employ a method of measuring the electrical resistivity of metal objects of random shapes. Using this method, it is possible to measure the resistivity of materials without the need to manufacture them into wires or ribbons. Methods. The solution to the problem was carried out by the finite element method via the COMSOL Multiphysics 5.6 simulation program in a cartesian coordinate system and the resistance between two points of the metal sample was measured by the 4-wire method. Results. A similar resistance value was obtained when the measuring terminals were placed in different places. The difference between them was within 1,5 % and the obtained values were close to the values given by the literature for the electrical resistivity of electrical steels. Terminal size influences the measured conductivity and a max error of 5,2 % was estimated. Practical value. A method of estimating the resistivity of materials without the need to manufacture them into specific shapes, like wires or ribbons, for which analytical expressions between resistivity and resistance are easily derived.Вступ. Питомий електричний опір є важливою характеристикою матеріалу в галузі електротехніки та матеріалознавства. Існує кілька методів, які можна використовувати для вимірювання опору, наприклад, 4-провідний метод, який пов’язує опір з падінням напруги при заданому струмі, але для визначення питомого опору за значенням опору потрібен аналітичний вираз для даної системи, який вимагає достатнього математичного апарату для опису складних форм. Тому ми використовуємо розрахунки методом скінченних елементів до розрахунку питомого опору металевого матеріалу. Цей підхід вже використовувався в минулому для різних матеріалів, таких як бетон та алюміній. Потім ми порівнюємо цей метод з аналітичним виразом, який завдяки інтуїції може достатньо апроксимувати рішення. Після цього матеріал знову використовується для перевірки електричної ізотропії зразка. Новизна. Розроблено метод шляхом поєднання результатів експериментальних досліджень та результатів математичного моделювання процесу визначення електропровідності металів. Мета – описати та застосувати метод вимірювання питомого електичного опору металевих предметів довільної форми. Використовуючи цей метод, можна вимірювати питомий опір матеріалів без необхідності виготовлення дротів або стрічок. Методи. Розв’язання задачі здійснювалося методом скінченних елементів за допомогою програми моделювання COMSOL Multiphysics 5.6 у декартової системі координат, а опір між двома точками металевого зразка вимірювався 4-провідним методом. Результати. Отримано аналогічне значення опору під час розміщення вимірювальних клем у різних місцях. Різниця між ними знаходилася в межах 1,5% і отримані значення були близькими до наведених у літературі значень електричного опору електротехнічних сталей. Розмір клеми впливає на провідність, що вимірюється, максимальна похибка становить 5,2 %. Практична цінність. Метод оцінки питомого опору матеріалів без необхідності надання їм певної форми, наприклад, дроту або стрічок, для якого легко отримати аналітичні вирази між питомим опором та опором
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