1.Yeduri Sreenivasa Reddy, Abhinav Kumar , Om Jee Pandey, and Linga Reddy Cenkeramaddi, “Spectrum Cartography Techniques, Challenges, Opportunities, and Applications: A Survey” has been accepted for publication in the Elsevier Pervasive and Mobile Computing Journal.
Keywords:Channel gain map,Channel state information,Interference map,Mean absolute error (MAE), Mean square error (MSE), Normalized MSE (NMSE), Power spectral density map, Power map, Radio frequency (RF) power, RF map, Root MSE (RMSE),Spectrum cartography, Spectrum map, Transmitter locations
Abstract:The spectrum cartography finds applications in several areas such as cognitive radios, spectrum aware communications, machine-type communications, Internet of Things, connected vehicles, wireless sensor networks, and radio frequency management systems, etc. This paper presents a survey on state-of-the-art of spectrum cartography techniques for the construction of various radio environment maps (REMs). Following a brief overview on spectrum cartography, various techniques considered to construct the REMs such as channel gain map, power spectral density map, power map, spectrum map, power propagation map, radio frequency map, and interference map are reviewed. In this paper, we compare the performance of the different spectrum cartography methods in terms of mean absolute error, mean square error, normalized mean square error, and root mean square error. The information presented in this paper aims to serve as a practical reference guide for various spectrum cartography methods for constructing different REMs. Finally, some of the open issues and challenges for future research and development are discussed.
2.Venkata satya chidambara swamy Vaddadi, Saidi Reddy Parne, Vijeesh V. P., Suman Gandi and Linga Reddy Cenkeramaddi, “Design and Implementation of Density Sensor for Liquids using Fiber Bragg Grating Sensor,” has been accepted for publication in the IEEE Photonics Journal.
Keywords:Liquids,Fiber gratings,Temperature measurement,Optical fiber sensors,Density measurement, Temperature sensors,Wavelength measurement
Abstract:In this paper, an optical fiber sensor based density sensor is proposed and demonstrated experimentally. The sensor is formed by fiber Bragg grating (FBG) sensor. The proposed sensor design is very simple and versatile for density measurements of liquids. The FBG strain sensor has one end mounted to a 3D printed rigid support, and the other end connected to a 3D manufactured clamp in this sensor design. A metal ball is suspended from this clamp by a non-stretchable cord. When it is completely immersed in liquid, the liquid buoyancy force acts on it. As a result, the strain in FBG varies depending on the force applied to the ball. This results in a wavelength shift in the FBG sensor. The proposed sensor design is tested for four distinct liquids, including water, gasoline, engine oil, and acetone, and the measured density values for each were tabulated. We estimated the density of water by varying the temperature and adding salt. Based on the measurements, the sensitivity of the sensor is 2.584 pm/Kg/m3 when the temperature of liquid changes and 3.375×10−2 pm/Kg/m3 when density varied by adding salt to the liquid is reported.
More details:DOI: 10.1109/JPHOT.2021.3129587