Reconfigurable Pattern Patch Antenna for Mid-Band 5G: A Review

New requirements in communication technologies make it imperative to rehash conventional features such as reconfigurable antennas to adapt with the future adaptability advancements. This paper presents a comprehensive review of reconfigurable antennas, specifically in terms of radiation patterns for adaptation in the upcoming Fifth Generation (5G) New Radio frequency bands. They represent the key of antenna technology for materializing a high rate transmission, increased spectral and energy efficiency, reduced interference, and improved the beam steering and beam shaping, thereby land a great promise for planar antennas to boost the mid-band 5G. This review begins with an overview of the underlying principals in reconfiguring radiation patterns, followed by the presentations of the implemented innovative antenna topologies to suit particular advanced features. The various adaptation techniques of radiation pattern reconfigurable planar antennas and the understanding of its antenna design approaches has been investigated for its radiation pattern enhancement. A variety of design configurations have also been critically studied for their compatibilities to be operated in the mid-band communication systems. The review provides new insights on pattern reconfigurable antenna where such antennas are categorized as beam steering antenna and beam shaping antennas where the operation modes and purposes are clearly investigated. The review also revealed that for mid-band 5G communication, the commonly used electronic switching such as PIN diodes have sufficient isolation loss to provide the required beam performance.     

The prerequisite for competition in the restructured wholesale Saudi electricity market

Protection of customers against monopoly is the first and main objective of the Saudi Electricity and Co-generation Regulatory Authority (ECRA). The second important objective, as recommended by the present study, is regulating natural monopoly businesses [Saudi electricity national grid (SENG) and Saudi electricity distribution (SED)] in addition to promoting real competition in competitive businesses [power supply providers (PSPs) and customer service providers (CSPs)]. Another four main objectives of ECRA are to promote the efficient use of energy and natural resources, to ensure a reasonable rate of return for PSPs and CSPs and at the same time to be fair to end-users, to ensure reasonable charges to SENG and SED services to be adequate for them to run the organization in a break-even manner and to maintain the system's security and reliability. The present paper discusses the way to improve and restructure the Saudi electricity market.     

Effect of oscillation amplitude on velocity distributions in an oscillatory baffled column (OBC)

This paper presents a numerical study of the effect of oscillation amplitude in oscillatory baffled column (OBC) using computational fluid dynamics. The numerical work was carried out for single phase liquid flow for an unsteady 3-D model using commercial software, Fluent (2006). This work was concentrated on the effect of oscillation amplitude. Three amplitudes of 5, 10 and 15 mm with constant frequency of 1 Hz are applied. Vortex and cycle average velocities at different points are analyzed. The studies show the maximum velocity for 5 mm, 10 mm and 15 mm in an OBC are 0.11 m/s, 0.25 m/s and 0.40 m/s respectively in the first cycle of oscillation. At a constant frequency, greater oscillation amplitude displaces the liquid to a further distance and builds a larger vortex. Vortex length was 1.5 times bigger when oscillation amplitude changes from 5 mm to 10 mm and 2 times when the amplitude is triple from 5 mm. The detailed validation is presented somewhere else; this research is focused on the effect of oscillation.     

Noise Adaptive Fuzzy Switching Median Filter for Salt-and-Pepper Noise Reduction

This letter presents a novel two-stage noise adaptive fuzzy switching median (NAFSM) filter for salt-and-pepper noise detection and removal. Initially, the detection stage will utilize the histogram of the corrupted image to identify noise pixels. These detected “noise pixels” will then be subjected to the second stage of the filtering action, while “noise-free pixels” are retained and left unprocessed. Then, the NAFSM filtering mechanism employs fuzzy reasoning to handle uncertainty present in the extracted local information as introduced by noise. Simulation results indicate that the NAFSM is able to outperform some of the salt-and-pepper noise filters existing in literature.      

Composition profiling of inhomogeneous SiGe nanostructures by Raman spectroscopy

In this work, we present an experimental procedure to measure the composition distribution within inhomogeneous SiGe nanostructures. The method is based on the Raman spectra of the nanostructures, quantitatively analyzed through the knowledge of the scattering efficiency of SiGe as a function of composition and excitation wavelength. The accuracy of the method and its limitations are evidenced through the analysis of a multilayer and of self-assembled islands.     

Exudates segmentation using inverse surface adaptive thresholding

This paper presents a new approach to detect exudates and optic disc from color fundus images based on inverse surface thresholding. The strategy involves the applications of fuzzy c-means clustering, edge detection, otsu thresholding and inverse surface thresholding. The main advantage of the proposed approach is that it does not depend on manually selected parameters that are normally chosen to suit the tested databases. When applied to two sets of databases the proposed method outperforms methods based on watershed segmentation and morphological reconstruction. The proposed method obtained 98.2 and 90.4 in terms of sensitivity for Standard Diabetic Retinopathy Database – Calibration Level 1 (DIARETDB1) and a local dataset provided by National University Hospital of Malaysia (NUHM), respectively.     

Effects of Residual Stress and Loading Geometry on Single-Edge Precracked-Beam (SEPB) Fracture-Toughness Test Results

The single-edge precracked-beam (SEPB) specimen test, using the "bridge indentation" method, is one of the standard test methods in the new ASTM standard for the determination of the fracture toughness of ceramics. In support of this effort, the effect of several test parameters on the fracture-toughness ( K _{I C} ) values was established. The effect of the residual stress, because of the indent and the alignment in three- and four-point bending, on the K _{I C} values was determined using aluminum nitride specimens. The results show that indent loads should be kept below 10 kgf, and the crack-plane angle should be <5°, to prevent artificially high K _{I C} values.     

Impaction of the stomachs in farmed ostriches (Struthio camelus) in Botswana

Impaction of the proventriculus, gizzard, and sometimes intestines due to sand was confirmed at postmortem in 25 cases involving ostriches (Struthio camelus). Although there was no age predisposition, impaction was more common in juvenile over 3 mo old. Clinical signs included sternal recumbency, outstretched neck, debility, and inability to stand. Palpation of the impacted stomachs gave a gritty sensation. Depletion of coronary fat was a consistent postmortem finding. The most common material causing impaction was sand. This report highlights impaction as one of the major causes of debility and death in intensively farmed ostriches. High levels of alkaline phosphatase coupled with low levels of plasma glucose, protein, and albumin detected in impacted ostriches may be useful diagnostic antemortem indicators of the syndrome.