3,379 research outputs found
Bandwidth EfïŹcient Root Nyquist Pulses for Optical Intensity Channels
Indoor diffuse optical intensity channels are bandwidth constrained due to the multiple reflected paths between the transmitter and the receiver which cause considerable inter-symbol interference (ISI). The transmitted signal amplitude is inherently non-negative, being a light intensity signal. All optical intensity root Nyquist pulses are time-limited to a single symbol interval which eliminates the possibility of finding bandlimited root Nyquist pulses. However, potential exists to design bandwidth efficient pulses. This paper investigates the modified hermite polynomial functions and prolate spheroidal wave functions as candidate waveforms for designing spectrally efficient optical pulses. These functions yield orthogonal pulses which have constant pulse duration irrespective of the order of the function, making them ideal for designing an ISI free pulse. Simulation results comparing the two pulses and challenges pertaining to their design and implementation are discussed
Accelerated modernity
This paper aims to show how current undergraduate students use social media in their daily lives, taking the first ten minutes of the day as a concentrated insight into their priorities of practice. The work draws on primary data from four focus groups of UK business students in higher education. Through the application of Rosaâs construct of social acceleration, initial findings indicate a hierarchy of priorities, shaped by economic, cultural and structural drivers in what social media is engaged with, in what sequence, and for what purpose. These choices reflect acceleration in the changes to the technology, the pace of social changes and the accelerated expectations of the pace of life. This article seeks to reimagine transmedia in the context of social media identity in an accelerated modernity. Here we have the intersection of three important rapidly changing constructs for the analysis of the use of media. These are the widespread, ubiquitous use of social media, the acceleration of late modernity and the impact of transmedia practice on how users engage with media
Effects of Neutrino Inverse Seesaw Mechanism on the Sparticle Spectrum in CMSSM and NUHM2
We study the implications of the inverse seesaw mechanism (ISS) on the
sparticle spectrum in the Constrained Minimal Supersymmetric Standard Model
(CMSSM) and Non-Universal Higgs Model (NUHM2). Employing the maximal value of
the Dirac Yukawa coupling involving the up type Higgs doublet provides a 2-3
GeV enhancement of the lightest CP-even Higgs boson mass. This effect permits
one to have lighter colored sparticles in the CMSSM and NUHM2 scenarios with
LSP neutralino, which can be tested at LHC14. We present a variety of LHC
testable benchmark points with the desired LSP neutralino dark matter relic
abundance.Comment: 18 pages, 10 figures and 2 table
Footwear-integrated force sensing resistor sensors: A machine learning approach for categorizing lower limb disorders
Lower limb disorders are a substantial contributor to both disability and lower standards of life. The prevalent disorders affecting the lower limbs include osteoarthritis of the knee, hip, and ankle. The present study focuses on the use of footwear that incorporates force-sensing resistor sensors to classify lower limb disorders affecting the knee, hip, and ankle joints. The research collected data from a sample of 117 participants who wore footwear integrated with force-sensing resistor sensors while walking on a predetermined walkway of 9 meters. Extensive preprocessing and feature extraction techniques were applied to form a structured dataset. Several machine learning classifiers were trained and evaluated. According to the findings, the Random Forest model exhibited the highest level of performance on the balanced dataset with an accuracy rate of 96%, while the Decision Tree model achieved an accuracy rate of 91%. The accuracy scores of the Logistic Regression, Gaussian Naive Bayes, and Long Short-Term Memory models were comparatively lower. K-fold cross-validation was also performed to evaluate the modelsâ performance. The results indicate that the integration of force-sensing resistor sensors into footwear, along with the use of machine learning techniques, can accurately categorize lower limb disorders. This offers valuable information for developing customized interventions and treatment plans
Nanoplasmonics beyond Ohm's law
In tiny metallic nanostructures, quantum confinement and nonlocal response
change the collective plasmonic behavior with important consequences for e.g.
field-enhancement and extinction cross sections. We report on our most recent
developments of a real-space formulation of an equation-of-motion that goes
beyond the common local-response approximation and use of Ohm's law as the
central constitutive equation. The electron gas is treated within a
semi-classical hydrodynamic model with the emergence of a new intrinsic length
scale. We briefly review the new governing wave equations and give examples of
applying the nonlocal framework to calculation of extinction cross sections and
field enhancement in isolated particles, dimers, and corrugated surfaces.Comment: Invited paper for TaCoNa-Photonics 2012 (www.tacona-photonics.org),
to appear in AIP Conf. Pro
Performance evaluation of LoRaWAN for Green Internet of Things
LoRa is a long-range, low power and single-hop wireless technology that has been envisioned for Internet of Things (IoT) applications having battery driven nodes. Nevertheless, increase in number of end devices and varying throughput requirements impair the performance of pure Aloha in LoRaWAN. Considering these limitations, we evaluate the performance of slotted Aloha in LoRaWAN using extensive simulations. We employed packet error rate (PER), throughput, delay, and energy consumption of devices under different payload sizes and varying number of end devices as benchmarks. Moreover, an analytical analysis of backlogged and non-backlogged under slotted Aloha LoRaWAN environment is also performed. The simulation shows promising results in terms of PER and throughput compared to the pure Aloha. However, increase in delay has been observed during experimental evaluation.Finally, we endorse slotted aloha LoRaWAN for Green IoT Environment
Optimal Pricing and order quantity strategies for a firm offering multiple products facing customers cannibalization and random market demand
This paper studies a firmâs profitability problem offering its products into different market segments at differentiated prices. In order to improve the firmsâ profitability the firm needs to decide the prices and order quantities allocations for each market segment. In perfect market segmentation, it is assumed that the customers do not cannibalize between market segments. Whereas, in the case of imperfect market segmentation, the customers are assumed to cannibalize from a high price market segment to a lower price segment. Models to determine the optimal strategies for pricing and order quantity for the perfect as well as for the imperfect market segmentations are proposed with both the deterministic and stochastic customersâ demand. The study has shown that the perfect market segmentation always yields higher revenues compared to no segmentation for a firm facing both the deterministic and stochastic demand situations. In addition to this, the study has also shown that when cannibalization exists, a firm is still able to yield higher revenues compared to the case of no market segmentation facing both the deterministic and stochastic demands, however, greater the extent of cannibalization could result substantial losses in the profitability
Coupled-resonator optical waveguides: Q-factor and disorder influence
Coupled resonator optical waveguides (CROW) can significantly reduce light
propagation pulse velocity due to pronounced dispersion properties. A number of
interesting applications have been proposed to benefit from such slow-light
propagation. Unfortunately, the inevitable presence of disorder, imperfections,
and a finite Q value may heavily affect the otherwise attractive properties of
CROWs. We show how finite a Q factor limits the maximum attainable group delay
time; the group index is limited by Q, but equally important the feasible
device length is itself also limited by damping resulting from a finite Q.
Adding the additional effects of disorder to this picture, limitations become
even more severe due to destructive interference phenomena, eventually in the
form of Anderson localization. Simple analytical considerations demonstrate
that the maximum attainable delay time in CROWs is limited by the intrinsic
photon lifetime of a single resonator.Comment: Accepted for Opt. Quant. Electro
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