Experimental Study on Channel Reciprocity in Wireless Key Generation

Key generation from wireless channels is a promising alternative to public key cryptography for the establishment of cryptographic keys. It is the first paper to experimentally study the channel reciprocity principle of key generation, through investigating and quantifying channel measurements' cross-correlation relationship affected by noise and non-simultaneous measurements. Channel measurements, both received signal strength and channel state information, are collected from a real experimental platform using the wireless open access research platform (WARP) in a multipath office room. We found that in a slow fading channel (e.g., with a coherence time of about 50~ms), the channel cross-correlation is impacted greatly by noise but little by non-simultaneous measurements with a small sampling time difference (e.g., 0.06 ms). The resolution of the sampling time difference can be satisfied by wireless systems such as IEEE 802.11 to maintain an acceptable cross-correlation coefficient without affecting the bandwidth and communication efficiency.

Efficient statistical electromagnetic analysis in reverberant environments

This paper presents a statistical approach to the electromagnetic analysis of a system that lies within a reverberant cavity that has random or uncertain properties. The need to solve Maxwell's equations within the cavity is avoided by employing a relation known as the diffuse field reciprocity principle, which leads directly to the ensemble mean squared response of the system; all that is required is the impedance matrix of the system associated with radiation into infinite space. The general theoretical approach is presented, and the analysis is then applied to a five-cable bundle in a reverberation room © 2013 EMC Europe Foundation.

三维油藏数值模拟正反演算法研究

The dynamic prediction of complex reservoir development is one of the important research contents of dynamic analysis of oil and gas development. With the increase development of time, the permeabilities and porosities of reservoirs and the permeability of block reservoir at its boundaries are dynamically changing. How to track the dynamic change of permeability and porosity and make certain the permeability of block reservoir at its boundary is an important practical problem. To study developing dynamic prediction of complex reservoir, the key problem of research of dynamic prediction of complex reservoir development is realizing inversion of permeability and porosity. To realize the inversion, first of all, the fast forward and inverse method of 3-dimension reservoir simulation must be studied. Although the inversion has been widely applied to exploration and logging, it has not been applied to3-dimension reservoir simulation. Therefore, the study of fast forward and inverse method of 3-dimension reservoir simulation is a cutting-edge problem, takes on important realistic signification and application value. In this dissertation, 2-dimension and 3-dimension fluid equations in porous media are discretized by finite difference, obtaining finite difference equations to meet the inner boundary conditions by Peaceman's equations, giving successive over relaxation iteration of 3-dimension fluid equations in porous media and the dimensional analysis. Several equation-solving methods are compared in common use, analyzing its convergence and convergence rate. The alternating direction implicit procedure of 2-dimension has been turned into successive over relaxation iteration of alternating direction implicit procedure of 3-dimension fluid equations in porous media, which possesses the virtues of fast computing speed, needing small memory of computer, good adaptability for heterogeneous media and fast convergence rate. The geological model of channel-sandy reservoir has been generated with the help of stochastic simulation technique, whose cross sections of channel-sandy reservoir are parabolic shapes. This method makes the hard data commendably meet, very suit for geological modeling of containing complex boundary surface reservoir. To verify reliability of the method, theoretical solution and numerical solution are compared by simplifying model of 3-dimension fluid equations in porous media, whose results show that the only difference of the two pressure curves is that the numerical solution is lower than theoretical at the wellbore in the same space. It proves that using finite difference to solve fluid equations in porous media is reliable. As numerical examples of 3-dimension heterogeneous reservoir of the single-well and multi-well, the pressure distributions have been computed respectively, which show the pressure distributions there are clearly difference as difference of the permeabilities is greater than one order of magnitude, otherwise there are no clearly difference. As application, the pressure distribution of the channel-sandy reservoir have been computed, which indicates that the space distribution of pressure strongly relies on the direction of permeability, and is sensitive for space distributions of permeability. In this dissertation, the Peaceman's equations have been modified into solving vertical well problem and horizontal well problem simultaneously. In porous media, a 3D layer reservoir in which contain vertical wells and horizontal wells has been calculated with iteration. For channel-sandy reservoir in which there are also vertical wells and horizontal wells, a 3D transient heterogeneous fluid equation has been discretized. As an example, the space distribution of pressure has been calculated with iteration. The results of examples are accord with the fact, which shows the modification of Peaceman's equation is correct. The problem has been solved in the space where there are vertical and horizontal wells. In the dissertation, the nonuniform grid permeability integration equation upscaling method, the nonuniform grid 2D flow rate upscaling method and the nonuniform grid 3D flow rate upscaling method have been studied respectively. In those methods, they enhance computing speed greatly, but the computing speed of 3D flow rate upscaling method is faster than that of 2D flow rate upscaling method, and the precision of 3D flow rate upscaling method is better than that of 2D flow rate upscaling method. The results also show that the solutions of upscaling method are very approximating to that of fine grid blocks. In this paper, 4 methods of fast adaptive nonuniform grid upscaling method of 3D fluid equations in porous media have been put forward, and applied to calculate 3D heterogeneous reservoir and channel-sandy reservoir, whose computing results show that the solutions of nonuniform adaptive upscaling method of 3D heterogeneous fluid equations in porous media are very approximating to that of fine grid blocks in the regions the permeability or porosity being abnormity and very approximating to that of coarsen grid blocks in the other region, however, the computing speed of adaptive upscaling method is 100 times faster than that of fine grid block method. The formula of sensitivity coefficients are derived from initial boundary value problems of fluid equations in porous media by Green's reciprocity principle. The sensitivity coefficients of wellbore pressure to permeability parameters are given by Peaceman's equation and calculated by means of numerical calculation method of 3D transient anisotropic fluid equation in porous media and verified by direct method. The computing results are in excellent agreement with those obtained by the direct method, which shows feasibility of the method. In the dissertation, the calculating examples are also given for 3D reservoir, channel-sandy reservoir and 3D multi-well reservoir, whose numerical results indicate: around the well hole, the value of the sensitivity coefficients of permeability is very large, the value of the sensitivity coefficients of porosity is very large too, but the sensitivity coefficients of porosity is much less than the sensitivity coefficients of permeability, so that the effect of the sensitivity coefficients of permeability for inversion of reservoir parameters is much greater than that of the sensitivity coefficients of porosity. Because computing the sensitivity coefficients needs to call twice the program of reservoir simulation in one iteration, realizing inversion of reservoir parameters must be sustained by the fast forward method. Using the sensitivity coefficients of permeability and porosity, conditioned on observed valley erosion thickness in wells (hard data), the inversion of the permeabilities and porosities in the homogeneous reservoir, homogeneous reservoir only along the certain direction and block reservoir are implemented by Gauss-Newton method or conjugate gradient method respectively. The results of our examples are very approximating to the real data of permeability and porosity, but the convergence rate of conjugate gradient method is much faster than that of Gauss-Newton method.

NOISE GENERATED BY CAVITATION IN ORIFICE-PLATES WITH SOME GASEOUS EFFECTS.

An experimental investigation of the noise generated by cavitation in turbulent shear flows produced by confined sharp-edge orifice-plates is reported. The acoustic source strength of cavitation was determined by means of reciprocity type measurements. Experimentally determined scaling parameters are applied to a model to prototype scaling formula derived from dimensional analysis. The proposed formula is checked experimentally. Comparative photographic observations of the cavitation patterns for two different values of gas content are presented. The observed sound reduction, that occurs when supersaturated conditions exist downstream the orifice-plates, is explained by the effects of gas diffusion into the cavitation bubbles, and by simple acoustic attenuation.

Performatividade e gênero nas interações em teletandem

Pós-graduação em Estudos Linguísticos - IBILCE

AS MALDIÇÕES DO SALMO 137: O princípio da reciprocidade na justiça do Antigo Testamento como chave bíblica para a interpretação

Esta tese, baseada na exegese, defende que as maldições do Salmo 137 devem ser interpretadas levando-se em conta o princípio da reciprocidade praticado na justiça do AT, o famoso "olho por olho, dente por dente". Apresenta auxílios para a interpretação das maldições nos salmos; analisa o estado atual da questão; verifica a coerência ou não da utilização do termo "Salmo Imprecatório"; trata da difícil questão do contexto histórico dos salmos e, ainda, destaca alguns pontos que dificultam a interpretação cristã deste tipo de literatura. Ela trata das questões do texto, da estrutura, do gênero literário, da autoria, e do contexto de vida e histórico do Salmo 137. Além disso, apresenta paralelos deste gênero no mundo bíblico e compara versões do Salmo 137 em português. Mostra que no AT a palavra era tratada como algo que possui poder intrinseco; verifica como, normalmente, era feito o uso das maldições no AT em geral, preparando o caminho para a verificação de seu uso específico no Salmo 137; faz uma rápida retrospectiva histórica mostrando a longa trajetória de desavenças de Israel/Judá com Edom e Babilônia, o que leva o salmista a sentir-se no direito de pedir que estas duas nações sejam destruídas e sofram; levanta, ainda, a possibilidade do Salmo 137 não ser o único do Saltério com maldições contra Edom e Babilônia, e destaca que nesta composição existe uma automaldição e duas maldições, uma contra Edom e outra contra Babilônia, todas elas levando em conta o princípio da reciprocidade na justiça do AT.(AU)

AS MALDIÇÕES DO SALMO 137: O princípio da reciprocidade na justiça do Antigo Testamento como chave bíblica para a interpretação

Esta tese, baseada na exegese, defende que as maldições do Salmo 137 devem ser interpretadas levando-se em conta o princípio da reciprocidade praticado na justiça do AT, o famoso "olho por olho, dente por dente". Apresenta auxílios para a interpretação das maldições nos salmos; analisa o estado atual da questão; verifica a coerência ou não da utilização do termo "Salmo Imprecatório"; trata da difícil questão do contexto histórico dos salmos e, ainda, destaca alguns pontos que dificultam a interpretação cristã deste tipo de literatura. Ela trata das questões do texto, da estrutura, do gênero literário, da autoria, e do contexto de vida e histórico do Salmo 137. Além disso, apresenta paralelos deste gênero no mundo bíblico e compara versões do Salmo 137 em português. Mostra que no AT a palavra era tratada como algo que possui poder intrinseco; verifica como, normalmente, era feito o uso das maldições no AT em geral, preparando o caminho para a verificação de seu uso específico no Salmo 137; faz uma rápida retrospectiva histórica mostrando a longa trajetória de desavenças de Israel/Judá com Edom e Babilônia, o que leva o salmista a sentir-se no direito de pedir que estas duas nações sejam destruídas e sofram; levanta, ainda, a possibilidade do Salmo 137 não ser o único do Saltério com maldições contra Edom e Babilônia, e destaca que nesta composição existe uma automaldição e duas maldições, uma contra Edom e outra contra Babilônia, todas elas levando em conta o princípio da reciprocidade na justiça do AT.(AU)

AS MALDIÇÕES DO SALMO 137: O princípio da reciprocidade na justiça do Antigo Testamento como chave bíblica para a interpretação

Esta tese, baseada na exegese, defende que as maldições do Salmo 137 devem ser interpretadas levando-se em conta o princípio da reciprocidade praticado na justiça do AT, o famoso "olho por olho, dente por dente". Apresenta auxílios para a interpretação das maldições nos salmos; analisa o estado atual da questão; verifica a coerência ou não da utilização do termo "Salmo Imprecatório"; trata da difícil questão do contexto histórico dos salmos e, ainda, destaca alguns pontos que dificultam a interpretação cristã deste tipo de literatura. Ela trata das questões do texto, da estrutura, do gênero literário, da autoria, e do contexto de vida e histórico do Salmo 137. Além disso, apresenta paralelos deste gênero no mundo bíblico e compara versões do Salmo 137 em português. Mostra que no AT a palavra era tratada como algo que possui poder intrinseco; verifica como, normalmente, era feito o uso das maldições no AT em geral, preparando o caminho para a verificação de seu uso específico no Salmo 137; faz uma rápida retrospectiva histórica mostrando a longa trajetória de desavenças de Israel/Judá com Edom e Babilônia, o que leva o salmista a sentir-se no direito de pedir que estas duas nações sejam destruídas e sofram; levanta, ainda, a possibilidade do Salmo 137 não ser o único do Saltério com maldições contra Edom e Babilônia, e destaca que nesta composição existe uma automaldição e duas maldições, uma contra Edom e outra contra Babilônia, todas elas levando em conta o princípio da reciprocidade na justiça do AT.(AU)

Royalty payments : hearings before the Committee on Patents, House of Representatives, seventy-seventh Congress, first session, on H.J. Res. 32, H.J. Res. 73 and H.J. Res. 123, joint resolutions to define the principle of international reciprocity in the protection of American patents, trade-marks, secret formulas and processes, and copyrights by providing a method for assuring the payments of amounts due to persons in the United States from users thereof in countries restricting international payments from their territories /

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