Xem 1-19 trên 19 kết quả Propagation prediction
  • Many events in news articles don’t include time arguments. This paper describes two methods, one based on rules and the other based on statistical learning, to predict the unknown time argument for an event by the propagation from its related events. The results are promising – the rule based approach was able to correctly predict 74% of the unknown event time arguments with 70% precision.

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  • S/N ratio should be above a certain threshold (a function of modulation scheme). Signal power should be above the sensitivity threshold. Predict received signal strength when the transmitter and receiver have a clear line-of-sight path between them.

    ppt57p nhq_khtn 12-03-2011 81 33   Download

  • Tham khảo sách 'matlab – a fundamental tool for scientific computing and engineering applications – volume 2', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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  • A back -propagation artificial neural net has been trained to estimate the activity values of a set of 18 N-alkyl-N-acyl- -aminoamide derivatives from the results of molecular mechanics and RHF/PM3/SCF MO semi-empirical calculations. The input descriptors include molecular properties such as the partition coefficient P, 3d structure dependent parameters, charge dependent parameters, and topological descriptors.

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  • BRIEF HISTORY OF RF AND MICROWAVE WIRELESS SYSTEMS The wireless era was started by two European scientists, James Clerk Maxwell and Heinrich Rudolf Hertz. In 1864, Maxwell presented Maxwell's equations by unifying the works of Lorentz, Faraday, Ampere, and Gauss. He predicted the propagation of electromagnetic waves in free space at the speed of light. He postulated that light was an electromagnetic phenomenon of a particular wavelength and predicted that radiation would occur at other wavelengths as well.

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  • Scientists and mathematicians of the nineteenth century laid the foundation of telecommunication and wireless technology, which has affected all facets of modern society. In 1864, James C. Maxwell put forth fundamental relations of electromagnetic ®elds that not only summed up the research ®ndings of Laplace, Poisson, Faraday, Gauss, and others but also predicted the propagation of electrical signals through space. Heinrich Hertz subsequently veri®ed this in 1887 and Guglielmo Marconi successfully transmitted wireless signals across the Atlantic Ocean in 1900...

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  • The wireless era was started by two European scientists, James Clerk Maxwell and Heinrich Rudolf Hertz. In 1864, Maxwell presented Maxwell's equations by unifying the works of Lorentz, Faraday, Ampere, and Gauss. He predicted the propagation of electromagnetic waves in free space at the speed of light. He postulated that light was an electromagnetic phenomenon of a particular wavelength and predicted that radiation would occur at other wavelengths as well. His theory was not well accepted until 20 years later, after Hertz validated the electromagnetic wave (wireless) propagation.

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  • The history of mobile radio goes back almost to the origins of radio communication itself. The very early work of Hertz in the 1880s showed that electromagnetic wave propagation was possible in free space and hence demonstrated the practicality of radio communications. In 1892, less than ®ve years later, a paper written by the British scientist Sir William Crookes [1] predicted telegraphic communication over long distances using tuned receiving and transmitting apparatus.

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  • Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In modern materials science, fracture mechanics is an important tool in improving the mechanical performance of materials and components.

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  • This however brings about models and simulation, which is now applied generally to look into the inter-relationship between the parameters and its resultant effects on the environments (Abdulkareem et al., 2011). In this work, mathematical modelling that can be used to predict the quantity of heat radiation from gas flaring station will be developed. The developed model will be simulated and find interaction between various parameters such as distance, volume of gas flared, flared stack efficiency that influence the rate of heat radiation from gas flaring station.

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  • Planning Radio Networks In earlier chapters we discussed the characteristics of the radio propagation channel in some detail. We introduced methods for predicting the mean signal level within a small area in rural, suburban and urban environments and it became clear that this is a complicated process involving a knowledge of several factors, including the details of the terrain, the building clutter and the extent of foliage along the radio path.

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  • Characterisation of Multipath Phenomena In Chapter 3 we described some methods for predicting path losses, concentrating on those applicable to mobile communication systems. The discussion centred around techniques that deal principally with radio propagation over irregular terrain; methods of predicting signal strength in urban areas or in other environments, e.g. inside buildings, were deliberately left until Chapter 4. These propagation models are extremely important since the vast majority of mobile communication systems operate in and around centres of population....

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  • Sounding, Sampling and Simulation In the earlier chapters we discussed the characteristics of mobile radio channels in some detail. It emerged that there are certain parameters which provide an adequate description of the channel and it remains now to describe measuring equipment (channel sounders) that can be used to obtain experimental data from which these parameters can be derived.

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  • The first is Faraday’s law of induction, the second is Amp`ere’s law as amended by Maxwell to include the displacement current ∂D/∂t, the third and fourth are Gauss’ laws for the electric and magnetic fields. The displacement current term ∂D/∂t in Amp`ere’s law is essential in predicting the existence of propagating electromagnetic waves. Its role in establishing charge conservation is discussed in Sec. 1.7. Eqs. (1.1.1) are in SI units.

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  • A number of studies (see, for example, Iacoviello (2005) or Calza et al (2009)) apply the nancial accelerator to the housing market, where a similar mechanism is at work. A reduction in interest rates increases the value of collateral (housing) by increasing the discounted value of future user costs. The borrowers' debt capacity and consequently the demand for housing increases further, generating an even larger increase in house prices. Persistence and amplication would be mutually reinforcing and propagate the effect of the initial shock to interest rates on housing activity.

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  • Kihm et al. Nanoscale Research Letters 2011, 6:361 http://www.nanoscalereslett.com/content/6/1/361 NANO EXPRESS Open Access A new heat propagation velocity prevails over Brownian particle velocities in determining the thermal conductivities of nanofluids Kenneth D Kihm1,3*, Chan Hee Chon2, Joon Sik Lee3 and Stephen US Choi4 Abstract An alternative insight is presented concerning heat propagation velocity scales in predicting the effective thermal conductivities of nanofluids.

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  • Floods in urban areas due to levee overtopping and/or breaking may cause a lot of severe damage of property and lost of human lives. In case of river dike and/or dam break, the problem is characterized by the overland propagation of discontinuity fronts or hydraulic jumps. !t is of immense importance that urban planners and personnel have tools to assist in predicting and evaluating beforehand the flood process in such incidents.

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  • Low-frequency acoustic energy released within the Earth's crust and mantle mostly propagates - depending on the density and elasticity of the medium - through several types of seismic waves categorized as body waves (longitudinal P and transverse S) or surface waves (long L and ground roll R). The importance of seismic wave research lies not only in our ability to understand and predict earthquakes and tsunamis, it also reveals information on the Earth's composition and features in much the same way as it led to the discovery of Mohorovicic's discontinuity....

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  • However, it has been recently shown (Gabaix, 2010) that the cross sectional distribution of firms’ size matters a lot for the validity of this assumption. If the distribution of firms’ size has fat tails, then firm-level shocks may propagate to the overall economy. Gabaix indeed showed that the idiosyncratic shocks to the rate of growth in the sales of the largest US firms can predict the one-quarter-ahead growth rate of the US GDP.

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