Analysis Of Signal Attenuation Research Articles

A Review on Rainfall Measurement Based on Commercial Microwave Links in Wireless Cellular Networks.

As one of the most critical elements in the hydrological cycle, real-time and accurate rainfall measurement is of great significance to flood and drought disaster risk assessment and early warning. Using commercial microwave links (CMLs) to conduct rainfall measure is a promising solution due to the advantages of high spatial resolution, low implementation cost, near-surface measurement, and so on. However, because of the temporal and spatial dynamics of rainfall and the atmospheric influence, it is necessary to go through complicated signal processing steps from signal attenuation analysis of a CML to rainfall map. This article first introduces the basic principle and the revolution of CML-based rainfall measurement. Then, the article illustrates different steps of signal process in CML-based rainfall measurement, reviewing the state of the art solutions in each step. In addition, uncertainties and errors involved in each step of signal process as well as their impacts on the accuracy of rainfall measurement are analyzed. Moreover, the article also discusses how machine learning technologies facilitate CML-based rainfall measurement. Additionally, the applications of CML in monitoring phenomena other than rain and the hydrological simulation are summarized. Finally, the challenges and future directions are discussed.

Analysis of Signal Attenuation in Digital Terrestrial Television (DTTV) Broadcasting

This paper presents the prediction of signal attenuation Digital Terrestrial Television (DTTV) in Port Harcourt, Rivers State, Nigeria A signal Tracker (WS6916), Micronix Global Positioning System (GSP) module alongside a drive test was used to carry out the research work at Star times office, Olu-Obasanjo Road. The Power Density change with the varying distance between the receiver and the transmitter (Nobe B). For a more concise measurement, readings were taken between April and August 2019 (wet season) at different times of the day. The path loss exponent (n) of 4.7 reveals that Olu-Obasanjo road is an urban area. As the location changed, the path loss exponent (n) increased to 15.4, revealing the interference of tall buildings, and other forms of obstruction. The exponential shape of the graph shows a decaying signal along the distance axis with distance, expatiating that the inverse relationship between powers received (dbm) and distance (km). Attenuation was observed to have increased while increasing the distance between the transmitter and receiver. The results obtained were analyzed using the log-distance empirical model to obtain both the parameters of Path loss exponent and the Mean Square Error (MSE).

Analysis of signal attenuation in global shutter CMOS image sensor

This paper focuses on a new non-ideal phenomenon induced by the power supply crosstalk (PSC) of the row drive circuit in 8 T global shutter (GS) CMOS image sensors (CISs). A method to eliminate the non-ideal phenomenon is presented. Based on the circuit simulation, the relationship between the parasitic resistance and PSC is analyzed. The PSC would cause a charge leakage on the sampling hold (S/H) capacitors in the 8 T pixel, which in turn attenuates the output signal of the image sensor. Through the mathematical model of the in-pixel S/H circuit, the effect of PSC and exposure on signal attenuation is analyzed. To eliminate signal attenuation, this paper utilizes a separate power layout method that isolates the row drivers in different columns by using multiple power supplies. In contrast to the method of sharing the power supply, the proposed method can reduce the maximum power supply crosstalk noise from 1.17 V to 2.58 μV in the 2000 × 2 row drive array. Based on the 0.13 μm CMOS process, the measurement results of the 1st chip design using the typical shared power structure and the 2nd chip design using the separate power supply structure are compared. The measurement results show that the output signal of the 1st chip design is limited to about 303 ADU due to the power supply crosstalk. The saturated output signal of the 2nd chip design is 2200 ADU, which is in accordance with the theoretical signal output value (2200 ADU) when the pixel is saturated. The proposed method can effectively eliminate signal attenuation induced by the PSC, thereby improving the image quality of 8 T GS CIS.

SegCloud: a novel cloud image segmentation model using a deep convolutional neural network for ground-based all-sky-view camera observation

Abstract. Cloud detection and cloud properties have substantial applications in weather forecast, signal attenuation analysis, and other cloud-related fields. Cloud image segmentation is the fundamental and important step in deriving cloud cover. However, traditional segmentation methods rely on low-level visual features of clouds and often fail to achieve satisfactory performance. Deep convolutional neural networks (CNNs) can extract high-level feature information of objects and have achieved remarkable success in many image segmentation fields. On this basis, a novel deep CNN model named SegCloud is proposed and applied for accurate cloud segmentation based on ground-based observation. Architecturally, SegCloud possesses a symmetric encoder–decoder structure. The encoder network combines low-level cloud features to form high-level, low-resolution cloud feature maps, whereas the decoder network restores the obtained high-level cloud feature maps to the same resolution of input images. The Softmax classifier finally achieves pixel-wise classification and outputs segmentation results. SegCloud has powerful cloud discrimination capability and can automatically segment whole-sky images obtained by a ground-based all-sky-view camera. The performance of SegCloud is validated by extensive experiments, which show that SegCloud is effective and accurate for ground-based cloud segmentation and achieves better results than traditional methods do. The accuracy and practicability of SegCloud are further proven by applying it to cloud cover estimation.

Photoacoustic signal attenuation analysis for the assessment of thin layers thickness in paintings

This study introduces a novel method for the thickness estimation of thin paint layers in works of art, based on photoacoustic signal attenuation analysis (PAcSAA). Ad hoc designed samples with acrylic paint layers (Primary Red Magenta, Cadmium Yellow, Ultramarine Blue) of various thicknesses on glass substrates were realized for the specific application. After characterization by Optical Coherence Tomography imaging, samples were irradiated at the back side using low energy nanosecond laser pulses of 532 nm wavelength. Photoacoustic waves undergo a frequency-dependent exponential attenuation through the paint layer, before being detected by a broadband ultrasonic transducer. Frequency analysis of the recorded time-domain signals allows for the estimation of the average transmitted frequency function, which shows an exponential decay with the layer thickness. Ultrasonic attenuation models were obtained for each pigment and used to fit the data acquired on an inhomogeneous painted mock-up simulating a real canvas painting. Thickness evaluation through PAcSAA resulted in excellent agreement with cross-section analysis with a conventional brightfield microscope. The results of the current study demonstrate the potential of the proposed PAcSAA method for the non-destructive stratigraphic analysis of painted artworks.

Analysis of Signal Attenuation in UHF Band

This paper deals with signal attenuation in ultra-high-frequency bands caused by rain. We focus mainly on the effect of the rain on the radio waves propagation in the frequency band 2.1 GHz. Two exact approaches for investigating this dependency are used. In the first approach, we use the fitting probability density function for determination Rician distribution K-factor. In the second approach, we want to find more concrete rain-rate dependency with using linear regression. The results achieved in our long-term investigation clearly indicate that the strong impact of rain itself is a minor. So-called secondary rain impacts such as scattering of reflections from wet surfaces cause the main attenuation contribution.

Foundational dendritic processing that is independent of the cell type-specific structure in model primary neurons

It has long been known that primary neurons in the brain and spinal cord exhibit very distinctive dendritic structures. However, it remains unclear whether dendritic processing for signal propagation and channel activation over dendrites is a function of the cell type-specific dendritic structure. By applying an extended analysis of signal attenuation for the physiological distributions of synaptic inputs and active channels on dendritic branches, we first demonstrate that regardless of their specific structure, all anatomically reconstructed models of primary neurons display a similar pattern of directional signal attenuation and locational channel activation over their dendrites. Then, using a novel modeling approach that allows direct comparison of the anatomically reconstructed primary neurons with their reduced models that exclusively retain anatomical dendritic signaling without being associated with structural specificity, we show that the reduced model can accurately predict dendritic excitability of the anatomical model in both passive and active mode. These results indicate that the directional signaling, locational excitability and their relationship are foundational features of dendritic processing that are independent of the cell type-specific structure across primary neurons.

Empirical Model Selection with Fitting Approximation using Drive Test for DIT University, Dehradun

An exact radio propagation model is important for coping up with new challenges in the field of communication like: appropriate design, deployment and service management strategies for any wireless network. Analysis of path loss for outdoor propagation models is important for the purpose of signal coverage prediction, data reception, reception schemes, and analysis of signal attenuation under different environments. The aim of this work is to survey different outdoor propagation models with respect to empirical data collected from DIT University (formally Dehradun Institute of Technology), Dehradun by drive testing using TEMS Investigation tools at 1.8GHz. Predication of path loss is based on obtaining the mean received power distribution at specified receiver distance from the respective GSM base station. The measurement process was based on signal strength measurement and the study revealed that out of all the outdoor propagation models. COST Hata model, COST Hata W-B model and Ericsson model approximated the measurement characteristics and hence they can be deployed for network planning in this region and select the best propagation model for that region. Measurement process of signal strength and data collection methodology also discuss in this paper.

Comparison of Various Outdoor Propagation Models with Empirical Data Collection using TEMS 10. 0. 5 for DIT University, Dehradun

An exact radio propagation model is important for coping up with new challenges in the field of communication like: appropriate design, deployment and service management strategies for any wireless network. Analysis of outdoor propagation models is important for the purpose of signal coverage prediction, data reception analysis of performance parameters like Rx Lev, Rx Qual, FER, BER, reception schemes, and analysis of signal attenuation under different environments and in the determination of the optimum location for the purpose of installation of base stations. The aim of this work is to carry out a comparative study of different outdoor propagation models with respect to empirical data collected from DIT University (formally Dehradun Institute of Technology), Dehradun by drive testing using TEMS Investigation tools at 1.8GHz. This study involves obtaining the mean received power distribution at specified receiver distance from the respective GSM base station. The measurement process was based on signal strength measurement and the study revealed that out of all the outdoor propagation models. Only COST Hata model, COST Hata W-B model and Ericsson model approximated the measurement characteristics and hence they can be deployed for network planning in this region. Measurement process of signal strength and data collection methodology also discuss in this paper.

Analysis of Signal Attenuation of Continuous Wave in Drill String

In this study, the friction model in non-Newtonian drilling fluid is developed to evaluate the signal attenuation in the information transmission with the continuous wave. A model of transient non-Newtonian power- law pipe flow is developed by assuming a steady viscosity varied only with the radius and the solution is derived analytically in complex domain and time domain. The frequency-dependent friction is developed based on the solution in the time domain and is used in the pressure wave transmission. And the analysis results show that the highest pressure amplification with resonant frequency increases with the power-law index n increase and the resonant frequency increases with the n decrease.

Evaluating LNAPL contamination using GPR signal attenuation analysis and dielectric property measurements: Practical implications for hydrological studies

Groundwater and sub-surface contamination by Light Non-Aqueous Phase Liquids (LNAPLs) is one of the industrial world's most pressing environmental issues and a thorough understanding of the hydrological, physical and bio-chemical properties of the sub-surface is key to determining the spatial and temporal development of any particular contamination event. Non-invasive geophysical techniques (such as electrical resistivity, electromagnetic conductivity, Ground-Penetrating Radar, etc.) have proved to be successful sub-surface investigation and characterisation tools with Ground-Penetrating Radar (GPR) being particularly popular. Recent studies have shown that the spatial/temporal variation in GPR signal attenuation can provide important information on the electrical properties of the sub-surface materials that, in turn, can be used to assess the physical and hydrological nature of the pore fluids and associated contaminants. Unfortunately, a high percentage of current LNAPL-related GPR studies focus on contaminant mapping only, with little emphasis being placed on characterising the hydrological properties (e.g., determining contaminant saturation index, etc.). By comparing laboratory-based, dielectric measurements of LNAPL contaminated materials with the GPR signal attenuation observed in both contaminated and ‘clean’ areas of an LNAPL contaminated site, new insights have been gained into the nature of contaminant distribution/saturation and the likely signal attenuation mechanisms. The results show that, despite some practical limitations of the analysis technique, meaningful hydrological interpretations can be obtained on the contaminant properties, saturation index and bio-degradation processes. A generalised attenuation/saturation model has been developed that describes the physical and attenuation enhancement characteristics of the contaminated areas and reveals that the most significant attenuation is related to smeared zone surrounding the seasonally changing water table interface. It is envisaged that the model will provide a basis for the interpretation of GPR data from analogous LNAPL contaminated sites and provide investigators with an appreciation of the merits and limitations of GPR-based, attenuation analysis techniques for hydrological applications.

Analysis of signal attenuation for quantification of a planar imaging technique

An optical patternator can measure the fuel mass distribution of a spray usinglaser induced fluorescence (LIF) images obtained from a planar imaging technique.In the dense spray region, however, attenuation by scattering from particles in thepath of the detector is so significant that the true spray pattern mightbe altered into a false distribution. Therefore, the method to find thegeometric mean value of the intensities obtained from two cameras wasevaluated and verified in a solid-cone spray under the assumption thatthe optical depth is constant throughout the spray. The variation of theaveraged optical depth detected by the two cameras was negligible in thepresent study, so that the deviation of signal attenuation was within ±5%of the average value. The measurement of the mass distribution at Z = 25 mm using a single camera was estimated to have a large range of signalattenuation from 0 to 17%, while the method using two cameras has a small rangeof signal attenuation from 6.5% to 12.5%. Therefore, the effect of signalattenuation can be dealt with by the two-camera method. This method was alsoapplied to measure the size distribution by taking the ratio of fluorescence toMie-scattering signals. It was found that Mie-scattering and LIF signals wereattenuated at a similar rate within the range of the signal wavelength used in thismeasurement. Hence, the effect of signal attenuation on the size measurement wascancelled in the single image detection and agreed well with other techniques,such as PDPA.