Assessment of Satellite-Based Rainfall Products Using a X-Band Rain Radar Network in the Complex Terrain of the Ecuadorian Andes

Ground based rainfall information is hardly available in most high mountain areas of the world due to the remoteness and complex topography. Thus, proper understanding of spatio-temporal rainfall dynamics still remains a challenge in those areas. Satellite-based rainfall products may help if their rainfall assessment are of high quality. In this paper, microwave-based integrated multi-satellite retrieval for the Global Precipitation Measurement (GPM) (IMERG) (MW-based IMERG) was assessed along with the random-forest-based rainfall (RF-based rainfall) and infrared-only IMERG (IR-only IMERG) products against the quality-controlled rain radar network and meteorological stations of high temporal resolution over the Pacific coast and the Andes of Ecuador. The rain area delineation and rain estimation of each product were evaluated at a spatial resolution of 11 km2 and at the time of MW overpass from IMERG. The regionally calibrated RF-based rainfall at 2 km2 and 30 min was also investigated. The validation results indicate different essential aspects: (i) the best performance is provided by MW-based IMERG in the region at the time of MW overpass; (ii) RF-based rainfall shows better accuracy rather than the IR-only IMERG rainfall product. This confirms that applying multispectral IR data in retrieval can improve the estimation of rainfall compared with single-spectrum IR retrieval algorithms. (iii) All of the products are prone to low-intensity false alarms. (iv) The downscaling of higher-resolution products leads to lower product performance, despite regional calibration. The results show that more caution is needed when developing new algorithms for satellite-based, high-spatiotemporal-resolution rainfall products. The radar data validation shows better performance than meteorological stations because gauge data cannot correctly represent spatial rainfall in complex topography under convective rainfall environments.

Ultimate Fast Gyrosynchrotron Codes

The past decade has seen a dramatic increase in practical applications of microwave gyrosynchrotron emission for plasma diagnostics and three-dimensional modeling of solar flares and other astrophysical objects. This breakthrough became possible due to an apparently minor, technical development of fast gyrosynchrotron codes, which enormously reduced the computation time needed to calculate a single spectrum, while preserving the accuracy of the computation. However, the available fast codes are limited in that they can only be used for a factorized distribution over the energy and pitch angle, while the distribution of electrons over energy or pitch angle is limited to a number of predefined analytical functions. In realistic simulations, these assumptions do not hold; thus, the codes free from the mentioned limitations are called for. To remedy this situation, we extended our fast codes to work with an arbitrary input distribution function of radiating electrons. We accomplished this by implementing fast codes for a distribution function described by an arbitrary numerically defined array. In addition, we removed several other limitations of the available fast codes and improved treatment of the free–free component. The ultimate fast codes presented here allow for an arbitrary combination of the analytically and numerically defined distributions, which offers the most flexible use of the fast codes. We illustrate the code with a few simple examples.

Discrete Convolution-Based Energy Spectrum Configuring Method for the Analysis of the Intrinsic Radiation of 176Lu

There has been considerable interest in inorganic scintillators based on lutetium due to their favorable physical properties. Despite their advantages, lutetium-based scintillators could face issues because of the natural occurring radioisotope of 176Lu that is contained in natural lutetium. In order to mitigate its potential shortcomings, previous works have studied to understand the energy spectrum of the intrinsic radiation of 176Lu (IRL). However, few studies have focused on the various principal types of photon interactions with matter; in other words, only the full-energy peak according to the photoelectric effect or internal conversion have been considered for understanding the energy spectrum of IRL. Thus, the approach we have used in this study considers other principal types of photon interactions by convoluting each energy spectrum with combinations for generating the spectrum of the intrinsic radiation of 176Lu. From the results, we confirm that the method provides good agreement with the experiment. A significant contribution of this study is the provision of a new approach to process energy spectra induced by mutually independent radiation interactions as a single spectrum.

An Endmember Bundle Extraction Method Based on Multiscale Sampling to Address Spectral Variability for Hyperspectral Unmixing

With the improvement of spatial resolution of hyperspectral remote sensing images, the influence of spectral variability is gradually appearing in hyperspectral unmixing. The shortcomings of endmember extraction methods using a single spectrum to represent one type of material are revealed. To address spectral variability for hyperspectral unmixing, a multiscale resampling endmember bundle extraction (MSREBE) method is proposed in this paper. There are four steps in the proposed endmember bundle extraction method: (1) boundary detection; (2) sub-images in multiscale generation; (3) endmember extraction from each sub-image; (4) stepwise most similar collection (SMSC) clustering. The SMSC clustering method is aimed at solving the problem in determining which endmember bundle the extracted endmembers belong to. Experiments carried on both a simulated dataset and real hyperspectral datasets show that the endmembers extracted by the proposed method are superior to those extracted by the compared methods, and the optimal results in abundance estimation are maintained.

Hearing aid through skin sensory for profound deaf people

An individual with profound deafness or total hearing loss has a hearing threshold of 80dB or more. The ineffectiveness of hearing aids, surging costs and complex surgeries for cochlear implants have discouraged many to opt for these types of treatments. Hence, this research aims to provide an alternative hearing aid that stimulates “hearing” through the skin sensory, which is more affordable and accessible for the profoundly deaf or total hearing loss community. We have developed four initial vibrating transducers with single spectrum, which are strapped to a belt. The transducers pick up audible sounds through a microphone, amplifies the sound to a high-level signal, stimulating a vibration pattern on the human skin sensory. The belt was tested on 30 random people who identified as normal, partial, and profoundly deaf. When the belt was strapped to the individual’s waist, audible sound was played (stimulus) and the individual was asked whether he/she can feel a stimulation or vibration on their skin, and if so, state the sound source direction. Based on the test, all individuals were able to feel the vibrating stimulation on their skin, and they were also able to state the directions accurately. The various vibrating pattern that stimulates the human sensory system for the profoundly deaf can be learned over time, which could serve as useful information. However, interpreting and identifying the different types of vibrating pattern perceived through the skin remains a huge challenge for profoundly deaf people. As hearing through skin sensory is a very new area of research, there are very limited research articles published in this field. Thus far, this is the first study to evaluate the method of audio spectrum to develop hearing aid through skin sensory.

Impact of measured global spectrum variation on solar photovoltaic efficiencies

In comparisons of solar photovoltaic performance, variation in the spectrum of sunlight is infrequently considered. A single spectrum, AM1.5, is used as the standard condition both for comparison of competing solar cell technologies and evaluation of energy generation from solar power plants. The addition of solar spectrum variation provides a more relevant basis for comparison and reduces prediction error and its financial impacts. Ground-level measurements collected worldwide have been pooled to provide an extensive – though by no means comprehensive – sampling of the global variation in spectral irradiance. Applied to nine solar cell types, the resulting variation in solar cell performance indicates that a single spectrum is not sufficient for comparison of cells with different spectral responses. The performance of different cell types diverges from that under standard conditions. Increases in the degree of sun tracking decrease efficiency for cells with a narrow spectral response. Cells with two or more junctions tend to have efficiencies below that obtained under AM1.5. Of the nine cell types, silicon exhibits the least spectral sensitivity: the median relative variation at a single site is 3%.

Possibility to Construct a Machine for Primality Testing of Numbers

Like the optical prism to break white light up into its constituent spectral colors, the machine to show a prime as a single spectrum is proposed. From the theoretical analysis, it can be shown that the machine to recognize the prime number as a single spectrum can be realized by using the correlation function of Riemann zeta function. Moreover, this method can be used for a factorization of the integer consisted of two primes.

Determination of Silicon and Chromium in Gold Matrix Using Proton Induced X-Ray Emission

The research aimed at the determination of elemental concentrations of silicon and chromium in five geological samples at the mining site of Garin Awwal area using the method of PIXE for analyses. The choice PIXE method in this research was due to its high sensitivity and multi-element capability that analyzes any element from sodium to uranium in a single spectrum. PIXE technique of 2.5MeV proton beam was used to characterize five samples. Samples were irradiated and analyzed at Centre for Energy Research and Development, Ile-Ife, Osun State, Nigeria. From the Spectra and results generated, silicon and chromium are of commercial deposit in the area, alongside other elements such as Iron(Fe), Magnesium(Mg) and Aluminium(Al) which appear to be deposited in commercial quantities in the area.

Separation of the Structure Signal by the Maximal Overlap Discrete Wavelet Transform and Fast Fourier Transform

Power spectral density (PSD) is used for evaluating a structure’s vibration process. Moreover, PSD not only shows a discrete form of vibration but also presents various components in a vibration structure. The superposition of multiple vibration patterns on the same spectrum poses difficulty in analyzing the spectral information in the way needed to find the structure’s discrete vibration. This paper proposes a method for separating the synthetic vibration signal into a structure’s discrete vibration and other extraneous vibrations using the maximal overlap discrete wavelet transform (MODWT) method combined with the method of fast Fourier transform (FFT). With the combination of these two algorithms, MODWT and FFT, the signals of the synthesized vibration have been separated into component signals with different frequency ranges. This means that PSD will be formed, which is based on the combination of the single power spectra of the component signals. Thus, the single spectrum of each of these constructed components can be used to evaluate the types of discrete vibrations coexisting in a structure’s vibration process. The survey results in this paper show the sensitivity and suitability of select types of discrete vibrations to be separated out during the assessment of the structural change, so as to achieve the best possible plan for eliminating the unwanted and unexpected noise and vibration components.