Improvement of transmission quality using correlation of observational data in sensor networks

Author(s):  
Kentaro Kobayashi ◽  
Takaya Yamazato ◽  
Hiraku Okada ◽  
Masaaki Katayama
2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Wang ◽  
Dongming Peng ◽  
Honggang Wang ◽  
Hamid Sharif ◽  
Hsiao-Hwa Chen

Resource allocation for multimedia selective encryption and energy efficient transmission has not been fully investigated in literature for wireless sensor networks (WSNs). In this article, we propose a new cross-layer approach to optimize selectively encrypted image transmission quality in WSNs with strict energy constraint. A new selective image encryption approach favorable for unequal error protection (UEP) is proposed, which reduces encryption overhead considerably by controlling the structure of image bitstreams. Also, a novel cross-layer UEP scheme based on cipher-plain-text diversity is studied. In this UEP scheme, resources are unequally and optimally allocated in the encrypted bitstream structure, including data position information and magnitude value information. Simulation studies demonstrate that the proposed approach can simultaneously achieve improved image quality and assured energy efficiency with secure transmissions over WSNs.


Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3978 ◽  
Author(s):  
Yun-Shuai Yu ◽  
Yeong-Sheng Chen

Industrial wireless sensor networks (IWSNs) are a key technology for smart manufacturing. To identify the performance bottlenecks in an IWSN before its real-world deployment, the IWSN must first be evaluated through simulations using an error model which accurately characterizes the wireless links in the industrial scenario within which it will be deployed. However, the traditional error models used in most IWSN simulators are not derived from the real traces observed in industrial environments. Accordingly, this study first measured the transmission quality of IEEE 802.15.4 in a one-day experiment in a manufacturing factory and then used the measurement records to construct a second-order Markov frame-level error model for simulating the performance of an IWSN. The proposed model was incorporated into the simulator of OpenWSN, which is an industrial WSN implementing the related IEEE and IETF standards. The simulation results showed that the proposed error model improved the accuracy of the estimated transmission reliability by up to 12% compared to the original error model. Moreover, the estimation accuracy improved with increasing burst losses.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 198254-198264
Author(s):  
Wei-Chang Yeh ◽  
Yunzhi Jiang ◽  
Chia-Ling Huang ◽  
Neal N. Xiong ◽  
Cheng-Feng Hu ◽  
...  

1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.


1994 ◽  
Vol 144 ◽  
pp. 567-569
Author(s):  
V. Kulidzanishvili ◽  
D. Georgobiani

AbstractThe observational data of July 11, 1991 eclipse solar corona obtained by both electropolarimeter (EP) and CCD-matrix were processed. Using these data, the solar corona photometry was carried out. The results of EP data are compared with the ones of CCD data. It must be noted here that the CCD data give us only characteristics of the inner corona, while the EP data show the features of both the inner and middle corona up to 4R⊙. Standard flattening indexϵis evaluated from both data. The dependence of the flattening index on the distance from the solar limb is investigated. The isophotes in Na and Ca lines are plotted. Based on these data some ideas and conclusions on the type of the solar corona are presented.


1976 ◽  
Vol 32 ◽  
pp. 49-55 ◽  
Author(s):  
F.A. Catalano ◽  
G. Strazzulla

SummaryFrom the analysis of the observational data of about 100 Ap stars, the radii have been computed under the assumption that Ap are main sequence stars. Radii range from 1.4 to 4.9 solar units. These values are all compatible with the Deutsch's period versus line-width relation.


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