Progressive refinement: more than a means to overcome limited bandwidth

2009 ◽  
Author(s):  
René Rosenbaum ◽  
Heidrun Schumann
Keyword(s):  
Limited Bandwidth ◽  
Progressive Refinement

Infant Responses to Recorded Sounds

1968 ◽  
Vol 11 (4) ◽  
pp. 811-816 ◽  
Author(s):  
Maurice I. Mendel
Keyword(s):  
White Noise ◽  
Narrow Band ◽  
Limited Bandwidth ◽  
Broadband Spectrum ◽  
Continuous Band

Thirty infants, ranging in age from 4 to 11 months, were tested with five different recorded sounds that varied in bandwidth and temporal configuration: a continuous band of white noise, the same band of noise interrupted twice per second, the crinkling of onionskin paper, a narrow band of noise centered at 3000 Hz, and a warbled 3000 Hz tone. With loudness and duration of the stimuli held constant, more responses occurred to sounds composed of a broadband spectrum than to those of a limited bandwidth. Temporal configuration of the sound had no effect on the number of responses elicited.

Virtualized Fog Network with Load Balancing for IoT based Fog-to-Cloud

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Istabraq M. Al-Joboury ◽  
Emad H. Al-Hemiary
Keyword(s):  
Load Balancing ◽  
Packet Loss ◽  
Fog Computing ◽  
Transport Protocol ◽  
Network Simulator ◽  
Huge Number ◽  
Message Queue ◽  
Limited Bandwidth ◽  
Cloud Architecture ◽  
Fog Network

Fog Computing is a new concept made by Cisco to provide same functionalities of Cloud Computing but near to Things to enhance performance such as reduce delay and response time. Packet loss may occur on single Fog server over a huge number of messages from Things because of several factors like limited bandwidth and capacity of queues in server. In this paper, Internet of Things based Fog-to-Cloud architecture is proposed to solve the problem of packet loss on Fog server using Load Balancing and virtualization. The architecture consists of 5 layers, namely: Things, gateway, Fog, Cloud, and application. Fog layer is virtualized to specified number of Fog servers using Graphical Network Simulator-3 and VirtualBox on local physical server. Server Load Balancing router is configured to distribute the huge traffic in Weighted Round Robin technique using Message Queue Telemetry Transport protocol. Then, maximum message from Fog layer are selected and sent to Cloud layer and the rest of messages are deleted within 1 hour using our proposed Data-in-Motion technique for storage, processing, and monitoring of messages. Thus, improving the performance of the Fog layer for storage and processing of messages, as well as reducing the packet loss to half and increasing throughput to 4 times than using single Fog server.

scholarly journals Single-Layer Line-Fed Broadband Microstrip Patch Antenna on Thin Substrates

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Roberto Vincenti Gatti ◽  
Riccardo Rossi ◽  
Marco Dionigi
Keyword(s):  
Patch Antenna ◽  
State Of The Art ◽  
Low Cost ◽  
Single Layer ◽  
Microstrip Antennas ◽  
Microstrip Patch Antenna ◽  
Layer Line ◽  
Limited Bandwidth ◽  
Microstrip Patch ◽  
Effective Design

In this work, the issue of limited bandwidth typical of microstrip antennas realized on a single thin substrate is addressed. A simple yet effective design approach is proposed based on the combination of traditional single-resonance patch geometries. Two novel shaped microstrip patch antenna elements with an inset feed are presented. Despite being printed on a single-layer substrate with reduced thickness, both radiators are characterized by a broadband behavior. The antennas are prototyped with a low-cost and fast manufacturing process, and measured results validate the simulations. State-of-the-art performance is obtained when compared to the existing literature, with measured fractional bandwidths of 3.71% and 6.12% around 10 GHz on a 0.508-mm-thick Teflon-based substrate. The small feeding line width could be an appealing feature whenever such radiating elements are to be used in array configurations.

scholarly journals Investigating Master–Slave Architecture for Underwater Wireless Sensor Network

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3000
Author(s):  
Sadeeq Jan ◽  
Eiad Yafi ◽  
Abdul Hafeez ◽  
Hamza Waheed Khatana ◽  
Sajid Hussain ◽  
...  
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Propagation Delay ◽  
Data Packet ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Term Survival ◽  
Limited Bandwidth ◽  
Delay Tolerant

A significant increase has been observed in the use of Underwater Wireless Sensor Networks (UWSNs) over the last few decades. However, there exist several associated challenges with UWSNs, mainly due to the nodes’ mobility, increased propagation delay, limited bandwidth, packet duplication, void holes, and Doppler/multi-path effects. To address these challenges, we propose a protocol named “An Efficient Routing Protocol based on Master–Slave Architecture for Underwater Wireless Sensor Network (ERPMSA-UWSN)” that significantly contributes to optimizing energy consumption and data packet’s long-term survival. We adopt an innovative approach based on the master–slave architecture, which results in limiting the forwarders of the data packet by restricting the transmission through master nodes only. In this protocol, we suppress nodes from data packet reception except the master nodes. We perform extensive simulation and demonstrate that our proposed protocol is delay-tolerant and energy-efficient. We achieve an improvement of 13% on energy tax and 4.8% on Packet Delivery Ratio (PDR), over the state-of-the-art protocol.

SecRET

2021 ◽  
Vol 15 (1) ◽  
pp. 1-26
Author(s):  
Sudip Misra ◽  
Tamoghna Ojha ◽  
Madhusoodhanan P
Keyword(s):  
Sensor Networks ◽  
Error Rates ◽  
Location Information ◽  
Underwater Sensor Networks ◽  
Node Localization ◽  
Limited Bandwidth ◽  
Secure Localization ◽  
Localization Scheme ◽  
Monitoring Application ◽  
Fundamental Requirement

Node localization is a fundamental requirement in underwater sensor networks (UWSNs) due to the ineptness of GPS and other terrestrial localization techniques in the underwater environment. In any UWSN monitoring application, the sensed information produces a better result when it is tagged with location information. However, the deployed nodes in UWSNs are vulnerable to many attacks, and hence, can be compromised by interested parties to generate incorrect location information. Consequently, using the existing localization schemes, the deployed nodes are unable to autonomously estimate the precise location information. In this regard, similar existing schemes for terrestrial wireless sensor networks are not applicable to UWSNs due to its inherent mobility, limited bandwidth availability, strict energy constraints, and high bit-error rates. In this article, we propose SecRET , a <underline>Sec</underline>ure <underline>R</underline>ange-based localization scheme empowered by <underline>E</underline>vidence <underline>T</underline>heory for UWSNs. With trust-based computations, the proposed scheme, SecRET , enables the unlocalized nodes to select the most reliable set of anchors with low resource consumption. Thus, the proposed scheme is adaptive to many attacks in UWSN environment. NS-3 based performance evaluation indicates that SecRET maintains energy-efficiency of the deployed nodes while ensuring efficient and secure localization, despite the presence of compromised nodes under various attacks.

scholarly journals Broadband terahertz absorber based on dispersion-engineered catenary coupling in dual metasurface

Nanophotonics ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Ming Zhang ◽  
Fei Zhang ◽  
Yi Ou ◽  
Jixiang Cai ◽  
Honglin Yu
Keyword(s):  
Optical Model ◽  
Dispersion Management ◽  
Bandwidth Extension ◽  
Limited Bandwidth ◽  
Terahertz Absorber ◽  
Simple Strategy ◽  
Management Ability ◽  
Potential Applications ◽  
Resolution Imaging ◽  
Different Thickness

AbstractTerahertz (THz) absorbers have attracted considerable attention due to their potential applications in high-resolution imaging systems, sensing, and imaging. However, the limited bandwidth of THz absorbers limits their further applications. Recently, the dispersion management of metasurfaces has become a simple strategy for the bandwidth extension of THz devices. In this paper, we used the capability of dispersion management to extend the bandwidth of THz absorbers. As a proof-of-concept, a dual metasurface-based reflective device was proposed for broadband near-unity THz absorber, which was composed of two polarization-independent metasurfaces separated from a metallic ground by dielectric layers with different thickness. Benefiting from the fully released dispersion management ability in adjusting the dimensions of the metasurfaces, we obtained an absorbance above 90% in the frequency range from 0.52 to 4.4 THz and the total thickness for the bandwidth approaching the theoretical Rozanov limit. The experimental results verified the ability of dispersion management in designing broadband absorbers and the performance of the designed absorber. The underlying physical mechanism of dispersion management was interpreted in the general equivalent circuit theory and transmission line model. In addition, the catenary optical model was used to further interpret the physics behind this dual metasurface. Moreover, we found that the alignment deviations between the dual metasurface had little impact on the performance of the designed absorber, which indicates that the dual-metasurface does not require center alignment and is easy to be fabricated. The results of this work could broaden the application areas of THz absorbers.

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