limited bandwidth
Recently Published Documents


TOTAL DOCUMENTS

412
(FIVE YEARS 136)

H-INDEX

22
(FIVE YEARS 6)

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260697
Author(s):  
Bin Huang ◽  
You Tang

Background Along with the vigorous development of Internet technology, increasing the functions of the various types of equipment, network communication easy and diversity, at the same time, the amount of data is very huge, under the network bandwidth limitations, through long lead to a data need to be cut into more, one by one, transfer times, information delay problems. Results Aiming at the problems of poor data integrity, low efficiency and poor serialization efficiency of traditional data storage information, this article introduces Protobuf technology to study the serialization of data storage information. The serpentine gap method is used to complete the allocation interval of the sequence nodes, so that the working state and the resting state always maintain a dynamic balance. According to the first-level rules, the storage data of the completed target node is obtained, and the grammatical structure and the semantics of the target data are analyzed, Meanwhile corresponding correspondences are established, and the data storage information is serialized. In order to verify the effectiveness of Protobuf’s data storage information serialization method, a comparative experiment is designed. By using three methods of HDVM, Redis and Protobuf to serialize JSON data, the comparative analysis shows that HDVM has the longest processing time and Protobuf has the shortest processing time, and the data integrity is not affected. The simulation data shows that the Protobuf serialization method has short conversion time, high space utilization, and the Obvious advantages in correctness and integrity. It is vary suitable for serialization of JSON data in the case of limited bandwidth.


Metrologia ◽  
2021 ◽  
Author(s):  
Mun-Seog Kim ◽  
Hehree Cho ◽  
Stephane Solve

Abstract A high-precision sampler, Fluke 8588A multimeter in the sampling mode, was utilised to perform differential sampling of AC waveforms with a programmable Josephson voltage standard. The systematic error on the differential sampling, induced by the inherent voltage-response characteristics and built-in low-pass filter of the sampler, was estimated. Experimental results and numerical simulations revealed that the sampler could be used for reliable differential sampling of AC waveforms at frequencies up to several kilohertz, with an appropriate number of the voltage steps per the waveform period, when the input bandwidth was set to 3 MHz. In addition, the sampler was compared to an integrating sampler, Keysight 3458A, now widely used for differential sampling. At 62.5 Hz, a key frequency in the future on-site key comparison of the differential sampling on AC voltage, the difference in RMS-amplitude values obtained by the differential sampling using the two different samplers is approximately 150 nV/V due to the systematic error caused by the limited bandwidth of 150~kHz for the integrating sampler.


Author(s):  
Yong-jian Zhao ◽  
Xiao-long Zhu ◽  
Pei-yu Luo ◽  
Ang Li ◽  
Wei Xiao ◽  
...  

Abstract Objective This paper proposes a new photoacoustic computed tomography (PACT) imaging system employing dual ultrasonic transducers with different frequencies. When imaging complex biological tissues, photoacoustic (PA) signals with multiple frequencies are produced simultaneously; however, due to the limited bandwidth of a single-frequency transducer, the received PA signals with specific frequencies may be missing, leading to a low imaging quality. Methods In contrast to our previous work, the proposed system has a compact volume as well as specific selection of the detection center frequency of the transducer, which can provide a comprehensive range for the detection of PA signals. In this study, a series of numerical simulation and phantom experiments were performed to validate the efficacy of the developed PACT system. Results The images generated by our system combined the advantages of both high resolution and ideal brightness/contrast. Conclusion The interchangeability of transducers with different frequencies provides potential for clinical deployment under the circumstance where a single frequency transducer cannot perform well.


Webology ◽  
2021 ◽  
Vol 18 (Special Issue 04) ◽  
pp. 1479-1498
Author(s):  
R. Deeptha

Mobile Ad Hoc NETwork (MANET) is the most desired topic of research amidst researchers mainly because of its flexibility and independent nature of network infrastructures. MANET's unique characteristics, like the dynamic behaviour related to network topology, limited bandwidth and battery resources, make routing a challenging task. Currently, several efficient routing protocols based on topology and geographical information have been proposed for MANET. However, most of them assume a trusted and cooperative oriented environment. With the influence of adversaries, the MANET routing protocols are vulnerable to various kinds of attacks. Recently, several research efforts have been made to counter these adversarial activities. This survey investigates the latest and on demand security concerns in MANET. This paper comprehensively discusses the existing attacks in the network layer, various categories of defense mechanisms in the literature, and their benefits and defects when applying to MANET. This paper also classifies the attacks and defense mechanisms based on the routing nature, such as topological and geographical. It also discusses intrusion detection systems as well as anonymous routing in MANETs. Finally, it discusses the challenges and future directions in routing security over the MANET environment.


2021 ◽  
Vol 2021 (1) ◽  
pp. 9-17
Author(s):  
Thibaud Biatek ◽  
Mohsen Abdoli ◽  
Mickael Raulet ◽  
Adam Wieckowski ◽  
Christian Lehman ◽  
...  

In the past few decades, the video broadcast ecosystem has gone through major changes; Originally transmitted using analog signals, it has been more and more transitioned toward digital, leveraging compression technologies and transport protocols, principally developed by MPEG. Along this way, the introduction of new video formats was achieved with standardization of new compression technologies for their better bandwidth preservation. Notably, SD with MPEG-2, HD with H.264, 4K/UHD with HEVC. In Brazil, the successive generations of digital broadcasting systems were developed by the SBTVD Forum, from TV-1.0 to TV-3.0 nowadays. The ambition of TV-3.0 is significantly higher than that of previous generations as it targets the delivery of IPbased signals for applications, such as 8K, HDR, virtual and augmented reality. To deliver such services, compressed video signals shall fit into a limited bandwidth, requiring even more advanced compression technologies. The Versatile Video Coding standard (H.266/VVC), has been finalized by the JVET committee in 2021 and is a relevant candidate to address the TV3.0 requirements. VVC is versatile by nature thanks to its dedicated tools for efficient compression of various formats, from 8K to 360°, and provides around 50% of bitrate saving compared to its predecessor HEVC. This paper presents the VVC-based compression system that has been proposed to the SBTVD call for proposals for TV-3.0. A technical description of VVC and an evaluation of its coding performance is provided. In addition, an end-to-end live transmission chain is demonstrated, supporting 4K real-time encoding and decoding with a low glass-to-glass latency.


Author(s):  
Nathanstee Q. Anayan ◽  
◽  
Virgil L. Penuela

The new era of technologies around the globe continues transforming the process of innovation particularly in the province of Romblon where the community is being active and updated about the trends of technology, however, due to the limited bandwidth signal of internet connection, their telecommunications are affected especially during this new normal where the Business Transactions, Learning Management System, and other Essential Services are done through online. The purpose of this study is to propose an IT business project especially a technology hub that will cater to and satisfy the needs of the community on the Island. The impact of this study is simply for connecting and moving people into the fastest and easiest way of communication using social media and other online platforms. The proposed Technology hub is composed of four areas, the Internet Café, Printing Press, Research Learning Area, and Photo Studio. This is very beneficial to the people in the community especially to the students that needs IT services. This study aims to help the people, the Local Government Unit, and the University to make their goals put into reality. This study will truly change and innovate the lives of the people even for the progress of the economy, culture, and lifestyle of the place. This study is also recommended for the implementation of Techno hub within the island since this could give an opportunity to give new jobs, especially for the IT professions. This is very responsive to the needs of the society in terms of socialization, communication, and education.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8000
Author(s):  
Johannes Hoffmann ◽  
Eric Elzenheimer ◽  
Christin Bald ◽  
Clint Hansen ◽  
Walter Maetzler ◽  
...  

Magnetoelectric (ME) sensors with a form factor of a few millimeters offer a comparatively low magnetic noise density of a few pT/Hz in a narrow frequency band near the first bending mode. While a high resonance frequency (kHz range) and limited bandwidth present a challenge to biomagnetic measurements, they can potentially be exploited in indirect sensing of non-magnetic quantities, where artificial magnetic sources are applicable. In this paper, we present the novel concept of an active magnetic motion sensing system optimized for ME sensors. Based on the signal chain, we investigated and quantified key drivers of the signal-to-noise ratio (SNR), which is closely related to sensor noise and bandwidth. These considerations were demonstrated by corresponding measurements in a simplified one-dimensional motion setup. Accordingly, we introduced a customized filter structure that enables a flexible bandwidth selection as well as a frequency-based separation of multiple artificial sources. Both design goals target the prospective application of ME sensors in medical movement analysis, where a multitude of distributed sensors and sources might be applied.


2021 ◽  
Author(s):  
◽  
Hang Yu

<p>Electromagnetic-based Wireless NanoSensor Networks (EM-WNSNs) operating in the Terahertz band (0.1 THz – 10 THz) will enable nano-scale applications and stimulate the evolution from the Internet of Things (IoT) to the Internet of Nano Things (IoNT). Data delivery, which is one of the key functionalities of EM-WNSNs, faces three major challenges that will affect network performance: the frequency-selective channel in the THz band due to molecular absorption, the limited ability to support networking functions due to their small size, and the limited bandwidth of the existing infrastructure for transferring sensed data to the Internet. However, to date, limited amount of research on data delivery has been done to address the peculiarities of IoNT from the networking perspective.  To fill the gap, in this thesis, data acquisition and dissemination solutions are studied for IoNT to improve the resource utilization efficiency during data delivery. Different from existing literatures that focus on standalone nanonetworks, this thesis investigates solutions for connecting nanodevices to the Internet.  In detail, the contributions of this thesis are composed of four components: First, a preliminary study namely the Channel-aware Forwarding (CForward) is conducted on multi-hop forwarding for THz networks; second, the On-demand Probabilistic polling (OP polling) is developed for IoNT with dynamic IoT bandwidth and channel conditions; third, a TTLbased Efficient Forwarding (TEForward) is designed for the polling-based nanonetworks under dynamic channel conditions; fourth, the Enhanced Adaptive Pulse Interval Scheduling (EAPIS) is implemented to collect data from event-based nanonetworks under limited IoT bandwidth.</p>


Sign in / Sign up

Export Citation Format

Share Document