A technique is presented for calculating the solution of Maxwell's equations using a CFIE based on the Cauchy integral and formulated in the guise of Clifford algebra. This formulation has a geometric interpretation leading to an iterative method of solution which is easily proven as convergent and correct for both perfectly reflective and perfectly transmissive interfaces. Simple test cases involving a cubic boundary and plane wave and dipole sources are used to investigate the numerical performance of the method.
In our model, we first calculate the conditional expectation for the complete-data likelihood, Q(Γ, Γ k−1) = E Φ|D,Γ k {log P (D, Φ|Γ)} = E Φ|D,Γ k { N ∑ i=1 log P (D i , ϕ i |Γ)} = N ∑ i=1
It is well-known that the analog FM radio channels in suburban areas are underutilized. Before reallocating the unused channels for other applications, a regulator must analyze the spectrum occupancy. Many researchers proposed the spectrum occupancy models to find vacant spectrum. However, the existing models do not analyze each channel individually. This paper proposes an approach consisting (i) a spectrum measurement strategy, (ii) an appropriate decision threshold, and (iii) criteria for channel classification, to find the unused channels. The measurement strategy monitors each channel’s activity by capturing the power levels of the passband and the guardband separately. The decision threshold is selected depending on the monitored channel’s activity. The criteria classifies the channels based on the passband’s and guardband’s duty cycles. The results show that the proposed channel classification can identify 42 unused channels. If the power levels of wholebands (existing model) were analyzed instead of passband’s and guardband’s duty cycles, only 24 unoccupied channels were found. Furthermore, we propose the interference criteria, based on relative duty cycles across channels, to classify the abnormally used channels into interference sources and interference sinks, which have 16 and 15 channels, respectively. This information helps the dynamic spectrum sharing avoid or mitigate the interferences.
A water management strategy to cope with severe climate change needs an efficient streamline model to play the important role of predicting the direction of flood-water. Generally a model is constructed using various image processing techniques which, depending on the particular area, can be quite complicated. In this paper two conceptually different approaches for determining streamlines from DEM data, in raster and vector forms, are reviewed. The advantages and limitations of both approaches are considered and compared using the numerical results of streamlines for the geometrically complex region containing Khao Luang National Park.
Abstract-This work presents the design of a magneto-electric dipole (MED) antenna for the base station antenna of FM radio broadcasting implementation. The advantages of MED antenna are high gain, stable and symmetrical radiation patterns in both electric and magnetic planes, and low back lobe radiation pattern. The antenna was designed and studied to achieve the optimal dimensions of configuration parameters. The prototype antenna was fabricated and measured to validate its S 11 , radiation patterns, and gain. The impedance bandwidth was 33.49%, and the average gain was 7.78 dBi at the entire operating frequency (88-108 MHz). The measured results are in good agreement with the simulated ones.
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