scholarly journals A Research Study on Protocol Stack of Space-Based Optical Backbone Network

2021 ◽  
Vol 11 (5) ◽  
pp. 2367
Author(s):  
Yu Zhang ◽  
Yabo Yuan ◽  
Bingli Guo ◽  
Qingsong Luo ◽  
Bingfeng Zhao ◽  
...  
Keyword(s):  
Satellite Communications ◽  
Protocol Stack ◽  
High Data ◽  
Backbone Network ◽  
Management Efficiency ◽  
Communication Capacity ◽  
Frame Switching ◽  
Efficient Control ◽  
Control And Management ◽  
Orbiting Systems

Facing the growing high data rate and large communication capacity demands, optical communications are widely recognized to be used to implement satellite communications. For a space-based optical backbone network, an appropriately designed protocol stack is important. In this paper, we proposed a protocol stack that is suitable for a space-based optical backbone network. Following this, we then used software to simulate this stack, built a hardware platform to test it, and finally, analyzed the results. The results showed that the proposed protocol stack was well designed to provide efficient control and management of the space-based optical backbone network. It could improve management efficiency by collecting resources and automatically calculating and building route paths. It could also facilitate data forwarding in intermediate satellite nodes with limited source and power, by using an advanced orbiting systems (AOS) frame switching scheme to avoid unnecessary processes, such as unpacking, upper-layer processing and repacking for passing services. The protocol stack could also support the use of unidirectional links to improve the link resource utilization. Finally, it could also provide transparent transmission for different kinds of services.

scholarly journals The COVID-19 pandemic preparedness simulation tool: CovidSIM

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Kristan A. Schneider ◽  
Gideon A. Ngwa ◽  
Markus Schwehm ◽  
Linda Eichner ◽  
Martin Eichner
Keyword(s):  
Decision Support ◽  
Simulation Models ◽  
Simulation Tool ◽  
Web Interface ◽  
Pandemic Preparedness ◽  
Seasonal Fluctuations ◽  
Seir Model ◽  
Peak Number ◽  
Efficient Control ◽  
Control And Management

Abstract Background Efficient control and management in the ongoing COVID-19 pandemic needs to carefully balance economical and realizable interventions. Simulation models can play a cardinal role in forecasting possible scenarios to sustain decision support. Methods We present a sophisticated extension of a classical SEIR model. The simulation tool CovidSIM Version 1.0 is an openly accessible web interface to interactively conduct simulations of this model. The simulation tool is used to assess the effects of various interventions, assuming parameters that reflect the situation in Austria as an example. Results Strict contact reduction including isolation of infected persons in quarantine wards and at home can substantially delay the peak of the epidemic. Home isolation of infected individuals effectively reduces the height of the peak. Contact reduction by social distancing, e.g., by curfews, sanitary behavior, etc. are also effective in delaying the epidemic peak. Conclusions Contact-reducing mechanisms are efficient to delay the peak of the epidemic. They might also be effective in decreasing the peak number of infections depending on seasonal fluctuations in the transmissibility of the disease.

Smart Home Design Based on Wireless Transmission Technology

2013 ◽  
Vol 291-294 ◽  
pp. 2132-2136 ◽  
Author(s):  
Tao Xu ◽  
Zhi Hua Hu ◽  
Jian Jun Wang ◽  
Hai Hui Song
Keyword(s):  
Smart Home ◽  
Video Data ◽  
Wireless Transmission ◽  
Security Requirements ◽  
Protocol Stack ◽  
Video Monitor ◽  
High Data ◽  
Tcp Protocol ◽  
Technology Users ◽  
Transmission Speed

In this article, a design of smart home control system which based on wireless transmission technology was presented. Through WIFI and 3G technology, users can monitor the equipments of their homes in everywhere. With WIFI’s ADHOC characteristics, equipments can be added or reduced easily. The high data transmission speed capability of WIFI and 3G makes the video monitor become possible. Both UDP and TCP protocol are used, thereinto, the UDP protocol is used to transmit video data, while the TCP protocol is used to transmit the data with security requirements. In order to save cost, Lwip protocol stack have been used to implement the requirements of this design.

scholarly journals No Free Lunch—Characterizing the Performance of 6TiSCH When Using Different Physical Layers

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4989
Author(s):  
Mina Rady ◽  
Quentin Lampin ◽  
Dominique Barthel ◽  
Thomas Watteyne
Keyword(s):  
Physical Layer ◽  
Industrial Applications ◽  
Data Rate ◽  
Protocol Stack ◽  
Physical Layers ◽  
Wireless Applications ◽  
High Data ◽  
Standardized Protocol ◽  
Performance Results ◽  
No Free Lunch

Low-power wireless applications require different trade-off points between latency, reliability, data rate and power consumption. Given such a set of constraints, which physical layer should I be using? We study this question in the context of 6TiSCH, a state-of-the-art recently standardized protocol stack developed for harsh industrial applications. Specifically, we augment OpenWSN, the reference 6TiSCH open-source implementation, to support one of three physical layers from the IEEE802.15.4g standard: FSK 868 MHz which offers long range, OFDM 868 MHz which offers high data rate, and O-QPSK 2.4 GHz which offers more balanced performance. We run the resulting firmware on the 42-mote OpenTestbed deployed in an office environment, once for each physical layer. Performance results show that, indeed, no physical layer outperforms the other for all metrics. This article argues for combining the physical layers, rather than choosing one, in a generalized 6TiSCH architecture in which technology-agile radio chips (of which there are now many) are driven by a protocol stack which chooses the most appropriate physical layer on a frame-by-frame basis.

scholarly journals The Role and Challenges of Free-space Optical Systems

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Sushank Chaudhary ◽  
Angela Amphawan
Keyword(s):  
Free Space ◽  
Satellite Communications ◽  
Radio Networks ◽  
Optical Systems ◽  
Free Space Optics ◽  
Free Space Optical ◽  
Optical Carrier ◽  
High Data ◽  
Space Optics ◽  
Data Rates

AbstractComplementing wireless radio networks with free-space optics (FSO) achieves high data rates by modulating radio subcarriers over an optical carrier without expensive optical fiber cabling, enabling a pervasive platform for reaching underserved areas. In this paper, we review the main features of FSO for terrestrial and inter-satellite communications. Simulations of 1 Gbps data transmission through FSO links in both terrestrial and inter-satellite communications have been investigated to highlight potential atmospheric challenges in FSO.

scholarly journals Isoniazid, The Frontline of Resistance in Mycobacterium tuberculosis

2002 ◽  
Vol 6 (2) ◽  
Author(s):  
James B. Whitney ◽  
Mark A. Wainberg
Keyword(s):  
Public Health ◽  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Genome Sequence ◽  
Molecular Mechanisms ◽  
Close Association ◽  
Drug Resistant ◽  
Efficient Control ◽  
Control And Management ◽  
Developed Nations

Tuberculosis is an ancient disease that has held close association with humans for millennia. Through persistence, this remarkably successful organism has managed to infect an estimated third of the world's population. Declining rates of tuberculosis in developed nations have masked an emerging epidemic of drug resistant cases that have been reported in almost every country under scrutiny. The recent completion of the genome sequence of Mycobacterium tuberculosis has mandated more efficient control and management of this disease. The momentum for this public health imperative will come from information gleaned from advances in genomics and related technologies towards deciphering molecular mechanisms of mycobacterial drug resistance.

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