Water-table variation in a sloping aquifer due to random recharge

Variation in the level of the water table is closely linked with recharge. Therefore, any uncertainty associated with the recharge rate is bound to affect the nature of the water-table fluctuation. In this note, a ditch-drainage problem of a sloping aquifer is considered to investigate the effect of uncertainty in the recharge rate on water-table fluctuation. The rate of recharge is taken as an exponentially decaying function with its decay constant as a Gaussian random variable. Expressions for the first two moments of the water-table height, i.e. mean and standard deviation, are presented. By using these expressions, the effect of uncertainty in the recharge rate on the water-table fluctuation has been analyzed with the help of a numerical example.     

Property of Self-Similarity Between Baseband and Modulated Signals

Mobile Networks and Applications - The increment of communication technologies and the development of signal processing require efficient identification techniques for communication...     

A Comprehensive Review on the Application of Internet of Thing (IoT) in Smart Agriculture

Wireless Personal Communications - IoT-based smart farming techniques have come up as one of the solutions to tackle the effect of climate change, water scarcity, etc. which are the prime reason...     

Mie‐Resonant Membrane Huygens' Metasurfaces

All‐dielectric metasurfaces have become a new paradigm for flat optics as they allow flexible engineering of the electromagnetic space of propagating waves. Such metasurfaces are usually composed of individual subwavelength elements embedded into a host medium or placed on a substrate, which often diminishes the quality of the resonances. The substrate imposes limitations on the metasurface functionalities, especially for infrared and terahertz frequencies. Here a novel concept of membrane Huygens' metasurfaces is introduced. The metasurfaces feature an inverted design, and they consist of arrays of holes made in a thin membrane of high‐index dielectric material, with the response governed by the electric and magnetic Mie resonances excited within dielectric domains of the membrane. Highly efficient transmission combined with the 2π phase coverage in the freestanding membranes is demonstrated. Several functional metadevices for wavefront control are designed, including beam deflector, a lens, and an axicon. Such membrane metasurfaces provide novel opportunities for efficient large‐area metadevices, whose advanced functionality is defined by structuring rather than by chemical composition.     

A Secure Stop and Wait Communication Protocol for Disturbed Networks

Wireless Personal Communications - Secure data communication is the need of hour today specifically when the wireless communication channel is insecure. We are proposing a protocol which can be...     

A near infrared optical reflector using one-dimensional photonic crystal structure containing chalcogenide glasses

The reflectivity of one-dimensional chalcogenide photonic crystal (CGPC) structure with the first order reflection band in near infrared (NIR) region is theoretically studied. Sb-Se and Ge-S chalcogenide glasses are used as high and low refractive index layers respectively, because these materials have zero absorption in NIR region. The transfer matrix method (TMM) is employed to calculate the reflective spectra of the proposed structure. The theoretical results of reflective spectra of bulk chalcogenide materials with the composition of Sb₄₀Se₆₀ and Ge₃₀S₇₀ for 4, 8, 12 and 15 layers and thicknesses of 117 nm and 183 nm respectively, at normal incidence, are close agreement with the experimental results. Furthermore, by increasing the number of layers of Sb₄₀Se₆₀ and Ge₃₀S₇₀, the reflection bands can be enhanced in the wider range of the NIR region for the polarization at different angles and thus the broadband omnidirectional reflector can be designed.     

Empirical models for net-length probability distribution and applications

In this paper, we propose a novel, empirical, and parameterizable model for estimating the probability distribution of wire length for each net in a placed netlist. The model is simple and fast to compute. We did extensive experimentation with state-of-the-art commercial (Cadence) and academic (Parquet and Labyrinth) tools and validated our model. Our distribution model was around three times more accurate than assuming half-perimeter bounding box as the fixed net-length estimate. Since the model is parameterizable it can be easily tailored for different routing tools and benchmarks. This model would be very useful in defining a full fledged probabilistic design automation methodology in which various design metrics are optimized from a probabilistic point of view. We also discuss the application of our model in a novel probabilistic approach to the buffer insertion problem.     

Tunnel diode-loaded rectangular microstrip antenna for millimeter range

Theoretical investigations conducted for Ge tunnel diode-integrated rectangular patch antenna reveals that such an antenna exhibits frequency tunability with the bias voltage. The Ge tunnel diode-loaded patch can be operated in the millimeter range (51.042-54.013 GHz). The range of frequency obtainable for operation is 2971 MHz. The radiation pattern shows variation with the bias voltage and the radiated power, the beamwidth and the directivity vary inversely with the bias voltage. Thus, the Ge tunnel diode-loaded patch can be used to achieve electronic tuning (BW=5.66%) with the bias voltage.     

Countermeasures for Primary User Emulation Attack: A Comprehensive Review

Wireless Personal Communications - Cognitive radio (CR) is a flexible wireless network that can solve the scarcity and underutilization problem of the spectrum by permitting unlicensed users to...     

Optical GFDM: an improved alternative candidate for indoor visible light communication

Photonic Network Communications - This paper proposes generalized frequency division multiplexing (GFDM) for indoor visible light communication (VLC). GFDM is a flexible multi-carrier scheme that...