502 research outputs found
EAST: Energy Efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
In this paper, we propose Energy-efficient Adaptive Scheme for Transmission
(EAST) in WSNs. EAST is IEEE 802.15.4 standard compliant. In this approach,
open-loop is used for temperature-aware link quality estimation and
compensation. Whereas, closed-loop feedback helps to divide network into three
logical regions to minimize overhead of control packets on basis of Threshold
transmitter power loss (RSSIloss) for each region and current number of
neighbor nodes that help to adapt transmit power according to link quality
changes due to temperature variation. Simulation results show that propose
scheme; EAST effectively adapts transmission power to changing link quality
with less control packets overhead and energy consumption compared to classical
approach with single region in which maximum transmitter power assigned to
compensate temperature variation
Crystal structure of 3-{(E)-[(3, 4-dichloro-phenyl)imino]methyl}benzene-1, 2-diol
The authors acknowledge the provision of funds for the purchase of diffractometer and encouragement by Dr.Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan.Peer reviewedPublisher PD
A Novel Hybrid GWO-LS Estimator for Harmonic Estimation Problem in Time Varying Noisy Environment
The power quality of the Electrical Power System (EPS) is greatly affected by electrical harmonics. Hence, accurate and proper estimation of electrical harmonics is essential to design appropriate filters for mitigation of harmonics and their associated effects on the power quality of EPS. This paper presents a novel statistical (Least Square) and meta-heuristic (Grey wolf optimizer) based hybrid technique for accurate detection and estimation of electrical harmonics with minimum computational time. The non-linear part (phase and frequency) of harmonics is estimated using GWO, while the linear part (amplitude) is estimated using the LS method. Furthermore, harmonics having transients are also estimated using proposed harmonic estimators. The effectiveness of the proposed harmonic estimator is evaluated using various case studies. Comparing the proposed approach with other harmonic estimation techniques demonstrates that it has a minimum mean square error with less complexity and better computational efficiency
Fine particulate matter in the tropical environment: monsoonal effects, source apportionment, and health risk assessment
The health implications of PM2:5 in the tropical
region of Southeast Asia (SEA) are significant as PM2:5
can pose serious health concerns. PM2:5 concentration and
sources here are strongly influenced by changes in the monsoon
regime from the south-west quadrant to the north-east
quadrant in the region. In this work, PM2:5 samples were
collected at a semi-urban area using a high-volume air sampler
at different seasons on 24 h basis. Analysis of trace elements
and water-soluble ions was performed using inductively
coupled plasma mass spectroscopy (ICP-MS) and ion
chromatography (IC), respectively. Apportionment analysis
of PM2:5 was carried out using the United States Environmental
Protection Agency (US EPA) positive matrix factorization
(PMF) 5.0 and a mass closure model. We quantitatively
characterized the health risks posed to human populations
through the inhalation of selected heavy metals in
PM2:5. 48% of the samples collected exceeded the World
Health Organization (WHO) 24 h PM2:5 guideline but only
19% of the samples exceeded 24 h US EPA National Ambient
Air Quality Standard (NAAQS). The PM2:5 concentration
was slightly higher during the north-east monsoon compared
to south-west monsoon. The main trace metals identified
were As, Pb, Cd, Ni, Mn, V, and Cr while the main ions
were SO
Dual-sense slot-based CP MIMO antenna with polarization bandwidth reconfigurability
In this letter, a compact, planar circularly polarized (CP) sub-GHz slot-based multiple-input-multiple-output (MIMO) antenna with dual sense CP along with polarization bandwidth reconfigurability is presented. The pentagonal reactively loaded slot is fed by two folded tapered feedlines to achieve CP. The antenna offers left-hand-circular polarization (RHCP) with the as well as right hand circular polarization (LHCP). The antenna exhibit linearly polarization (LP) by exciting two ports simultaneously. Moreover, the antenna CP resonance can be reconfigured by varying the capacitance of the varactor diode. The antenna has a wide −10 dB operating frequency band from 578–929 MHz. while the axial ratio (AR) bandwidth ranges from 490–810 MHz. Moreover, the two elements MIMO are optimized and placed on compact dimensions 100 × 100 × 0.76 mm3 to realize pattern diversity. The antenna’s key characteristics are compact size, wide-band sub-GHz operation, dual sense CP, polarization bandwidth reconfigurability and good MIMO performance. Thus, it is a suitable candidate to be utilized in CubeSats applications in sub-GHz bands
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