Search

The compression method for wellbore trajectory data is crucial for monitoring wellbore stability. However, classical methods like methods based on Huffman coding, compressed sensing, and Differential Pulse Code Modulation (DPCM) suffer from low real-time performance, low compression ratios, and large errors between the reconstructed data and the source data. To address these issues, a new compression method is proposed, leveraging a deep autoencoder for the first time to significantly improve the compression ratio. Additionally, the method reduces error by compressing and transmitting residual data from the feature extraction process using quantization coding and Huffman coding. Furthermore, a mean filter based on the optimal standard deviation threshold is applied to further minimize error. Experimental results show that the proposed method achieves an average compression ratio of 4.05 for inclination and azimuth data; compared to the DPCM method, it is improved by 118.54%. Meanwhile, the average mean square error of the proposed method is 76.88, which is decreased by 82.46% when compared to the DPCM method. Ablation studies confirm the effectiveness of the proposed improvements. These findings highlight the efficacy of the proposed method in enhancing wellbore stability monitoring performance. [ABSTRACT FROM AUTHOR]

Copyright of Elektronik Industrie is the property of Hüthig GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Medical imaging plays a significant role in clinical practice. Storing and transferring a large volume of images can be complex and inefficient. This paper presents the development of a new compression technique that combines the fast discrete curvelet transform (FDCvT) with state table set partitioning in the hierarchical trees (STS) encoding scheme. The curvelet transform is an extension of the wavelet transform algorithm that represents data based on scale and position. Initially, the medical image was decomposed using the FDCvT algorithm. The FDCvT algorithm creates symmetrical values for the detail coefficients, and these coefficients are modified to improve the efficiency of the algorithm. The curvelet coefficients are then encoded using the STS and differential pulse-code modulation (DPCM). The greatest amount of energy is contained in the coarse coefficients, which are encoded using the DPCM method. The finest and modified detail coefficients are encoded using the STS method. A variety of medical modalities, including computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI), are used to verify the performance of the proposed technique. Various quality metrics, including peak signal-to-noise ratio (PSNR), compression ratio (CR), and structural similarity index (SSIM), are used to evaluate the compression results. Additionally, the computation time for the encoding (ET) and decoding (DT) processes is measured. The experimental results showed that the PET image obtained higher values of the PSNR and CR. The CT image provides high quality for the reconstructed image, with an SSIM value of 0.96 and the fastest ET of 0.13 seconds. The MRI image has the shortest DT, which is 0.23 seconds. [ABSTRACT FROM AUTHOR]

In this paper, Barker code thermography is used to detect delamination defects incarbon fiber reinforced polymer (CFRP). Detection capability of this imaging technique is assessed through quantitative analysis of the signal-to-noise ratio (SNR) in the acquired feature images. An infrared thermography experimental system has been developed to implement the Barker code modulation for pulse compression excitation signals. A reference CFRP specimen with different diameter-to-depth ratio defects was tested. Three thermal wave imaging algorithms, namely principal component analysis (PCA), fitting correlation coefficient (FCC) and total harmonic distortion (THD), have been applied to process the acquired infrared images sequences, and determine SNR values characterizing the processing results. The experimental results show that Barker code thermography has the advantages of simple modulation and easy implementation. Also, the PCA algorithm outperforms the techniques of FCC and THD in terms of the SNR to enable effective identification defects in CFRP. [ABSTRACT FROM AUTHOR]

The study has outlined various photonic crystal fibers (PCFs) configurations for the key solution to the optimization of data rates transmission. The proposed fibers that are namely octagonal photonic crystal fiber (OPCF), hexagonal photonic crystal fiber (HPCF), and elliptical photonic crystal fiber (E-PCF) are used in the system. The dispersion parameter coefficient, pulse broadening variations, and data rates transmission are examined for proposed fibers under the same fiber lengths and number of quantization level with using pulse code modulation (PCM). The system performance is enhanced with OPCF with reducing dispersion factor, pulse broadening effects and consequently increasing data rates transmission. [ABSTRACT FROM AUTHOR]

Light field imaging, which can gather global visual data, has garnered attention from the computer world in recent years. Inter and intra frame correlation, big data storage, and poor reconstructed depth quality still plague light field area. In this work, greedy discrete wavelet and poincare recurrence network (GDW-PRN) is proposed for robust lossless image compression of hyper spectral images. First, spatial preprocessing is carried out using discrete reduction wavelet transform to remove unwanted artifacts. Next, dimensionality reduced visual data representation is applied by means of greedy band to the pre-processed images, therefore addressing the issues related to large data storage. Finally, lossless image compression is performed by utilizing poincare recurrence network. The entire proposed work was carried out on light field hyperspectral imagery data using MATLAB simulation tool. The proposed work has been compared to the existing methods such as compression based on differential pulse code modulation (C-DPCM), and 3D wavelet transform and spectrum learning with regression vector (3DWT-SRV). On comparison the acquired findings demonstrate that the suggested GDW-PRN process has high compression proportion light field image storage performance as well as leading to high peak signal to noise ratio (PSNR). [ABSTRACT FROM AUTHOR]

Information encryption technique has broad applications in individual privacy, military confidentiality, and national security, but traditional electronic encryption approaches are increasingly unable to satisfy the demands of strong safety and large bandwidth of high-speed data transmission over network. Optical encryption technology could be more flexible and effective in parallel programming and multiple degree-of-freedom data transmitting application. Here, we show a dual-layer optical encryption fluorescent polymer waveguide chip based on optical pulse-code modulation technique. Fluorescent oligomers were doped into epoxy cross-linking SU-8 polymer as a gain medium. Through modifying both the external pumping wavelength and operating frequency of the pulse-code modulation, the sender could ensure the transmission of vital information is secure. If the plaintext transmission is eavesdropped, the external pumping light will be switched, and the receiver will get warning commands of ciphertext information in the standby network. This technique is suitable for high-integration and high-scalability optical information encryption communications. Data security of internet is increasingly more demanding in the current era, yet the traditional electronic approach is limited in speed and efficiency. Here, the authors proposed a dual-layer optical encryption fluorescent polymer waveguide chip based on optical pulse-code modulation to mitigate the limitations. [ABSTRACT FROM AUTHOR]

Pulse code modulation (PCM) is an essential technique in digital communications, which transforms analog signals into digital data for transmission and processing. This technique is based on three fundamental processes: sampling, quantization and coding. With the growing demands on communication efficiency and quality, the optimization of PCM systems becomes crucial. This article explores advanced methods for the design and optimization of PCM systems, highlighting the use of sophisticated tools and algorithms to improve the overall performance of these systems. Approaches for bandwidth reduction, signal quality improvement, and error minimization are addressed. Innovative techniques such as variable pulse length coding and the use of optimization algorithms, such as genetic algorithms and the particle swarm optimization algorithm, are presented. Through practical case studies, it is demonstrated how these techniques can be applied to obtain superior results on real systems. This paper provides a comprehensive overview of advances in PCM modulation and its application in digital communication enhancement, offering recommendations for future research and applications in high-demand environments. [ABSTRACT FROM AUTHOR]

We propose a design of high-efficiency and direction-controllable spoof surface plasmon polaritons (SSPPs) coupler based on a Pancharatnam–Berry (PB) metasurface and a diode-controlled, linear-to-circular polarization conversion metasurface (PCM). The PB metasurface was designed to achieve high-efficiency excitation of SSPPs by manipulating the phase distribution. The PCM was placed above the PB metasurface at a certain distance, and the propagation direction of SSPPs could be controlled by changing the bias voltage of PCM. To validate the feasibility of the proposed design, a SSPPs coupler was fabricated and assessed. The experimental results were in good agreement with the simulation results. The conversion efficiency from the free space wave to SSPPs was obtained to be as high as 0.76 at 10 GHz, and the propagation direction of SSPPs became controllable under the normal incidence of x -polarized waves on the PCM. Compared to conventional devices such as prism, grating, and gradient-index metasurfaces, the proposed SSPPs coupler is more suitable for SSPPs excitation, thereby providing an interesting route toward developing plasmonic devices. [ABSTRACT FROM AUTHOR]

This paper focuses on Pulse Code Modulation (PCM) as a technology for digitizing analog signals. PCM is a widely used technique that enables precise encoding and transmission of analog information through digital pulse signals. The basic principles of PCM are explained here. PCM converts an analog signal into a digital form through sampling, quantization, and encoding. Sampling refers to the conversion of a continuous analog signal into discrete samples at regular time intervals. Then, quantization is applied to round each sample to the nearest possible quantization value, reducing the continuous range of values to discrete levels. Afterward, each quantized sample is encoded into a digital form. PCM is commonly used in various communication systems as well as in digital audio processing. In communication systems, PCM enables reliable transmission of voice signals, music, and other audio content over digital networks. In digital audio processing, PCM is used for recording, playback, and manipulation of sound, enabling high-quality reproduction and precise processing. [ABSTRACT FROM AUTHOR]

The correlation between pixels isn't completely removed, which degrade the performance of compression because the transform and quantization steps are bypassed in the lossless image compression with high efficiency video coding intra-prediction. To improve this situation, additional methods such as residual differential pulse code modulation is used in conjunction with the intra-prediction. The basic principle of residual differential pulse code modulation is based on the calculation of an enhanced residue of a pixel which is obtained with subtraction of the residue of left or top neighbor pixel from the residue of the pixel. In this study, a new residual differential pulse code modulation method, sampled-weighted residual differential pulse code modulation, considering an average of two or three neighboring pixels with weight is developed. A simple and fast algorithm is also proposed to determine the weight coefficients to be used in calculating the weighted average for the three neighboring pixels case. To obtain their compression performances the proposed sample-weighted residual differential pulse modulation methods are applied to various test images. The compression ratios of the compressed images are obtained. [ABSTRACT FROM AUTHOR]

Using an image compression hybrid model, the suggested research created a practical method for integrating learning system advantages with a decision logic framework. The emphasis here is that when integrated with the conventional image coding technology the potential usefulness of the decision logic is used as decision making. The execution is divided into three stages. In the first place, the image DCT representation of the image transformed to a different energy usage and is computed for different energy levels. A parallel processing of each power coefficient would then result in a substantially higher processing speed. In the second phase, differential pulse code modulation is used to compress the coefficients that correspond to the lowest energy level. Coefficients from the learning system are used as energy component, used to extract the coefficients. Finally, the algorithm is fed the results of the probabilistic decisions made in the second step of the program's development. To validate the proposed approach, the suggested method is tested over different Magnetic resonance imaging (MRI) medical samples. The simulation findings reveal good results and suggest that the reconstructed images are better than the conventional system. The developed Neuro-Fuzzy image compression model, results in attaining high accuracy and precision with reduced processing overhead and computation complexity. [ABSTRACT FROM AUTHOR]

In order to solve the problem of low translation accuracy caused by complex sentence parameters in traditional machine translation systems, a method based on deep learning was proposed. First, MCU SPCE061A is used to study the problem of complex digital signal. The training data in the synchronous translation server support the translation services of a large number of users, and the translation results were displayed through the session interface of the user terminal. The PMDL model is used to detect the keyword signal, record the PCM audio data, and slice the collected pulse code modulation signal, so as to wake up the artificial intelligence voice service. Then, this study establishes a speech recognition process that accurately outputs the speech-related semantics. In this paper, a manual interactive synchronous translation program is designed with the input text as the search criterion, and the set is trimmed to obtain the best translation effect. The experimental results show that the sentence translation accuracy of the system is 0.9 ∼ 1.0. It is proved that the method based on deep learning solves the problem of low accuracy of the traditional translation system. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The object of the research is the unmanned aerial vehicle monitoring system, the data exchange protocol and the unmanned aerial vehicle control line. A study was conducted, based on the results of which the unmanned aerial vehicle protection protocol and criteria were selected. An algorithm has been developed that ensures the establishment of the fact that the received radio radiation belongs to the class of radio signals of unmanned aerial vehicle remote control systems with pulse-position and pulse-code modulations. The results of practical testing of possible solutions are presented and the results of the functioning of the developed communication components are given. The user interface was developed, and the hybrid data exchange protocol was implemented in software. [ABSTRACT FROM AUTHOR]

Currently, with the huge increase in modern communication and network applications, the speed of transformation and storing data in compact forms are pressing issues. Daily an enormous amount of images are stored and shared among people every moment, especially in the social media realm, but unfortunately, even with these marvelous applications, the limited size of sent data is still the main restriction's, where essentially all these applications utilized the well-known Joint Photographic Experts Group (JPEG) standard techniques, in the same way, the need for construction of universally accepted standard compression systems urgently required to play a key role in the immense revolution. This review is concerned with Differential pulse code modulation (DPCM) and pixel-based techniques, where the spatial domain is exploited to compress images efficiently in terms of compression performance and preserving quality. The new pixel-based method overcomes predictive coding constraints with fewer residues and higher compression ratios. [ABSTRACT FROM AUTHOR]

• Report a novel laser array with one lamp pumping six Nd:YAG rods for programmable laser reconstruction in space-power-time domains. • Only one xenon flash lamp, with advantageously cylindrical pumping characteristics comparing with LD pumping source, is introduced to structure a high-out laser array which reduces complicated power supplies and liquid cooling system and has a potential of laser miniaturization. • The laser array has a total output energy of 1.53 J at an electrical input of 93.3 J, corresponding to an overall electro-optical conversion efficiency of 1.64 % and an electro-optical slope efficiency of 3.17 %. • Laser array with controllable space-power combination and an accurate time code modulated in the space-power-time domains are achieved. We report a novel laser array with one lamp pumping six Nd:YAG rods for programmable laser reconstruction in space-power-time domains. A sextuple ellipse pump cavity is proposed, and this scheme permits one xenon flash lamp with advantageously cylindrical pumping characteristics to simultaneously efficiently pump multiple Nd:YAG lasers in a laser system. The experimental setup was designed, and further experiments were carried out. The laser array can stably operate at a pumping rate of 1 Hz-10 Hz. Each laser beam of the six laser outputs has a divergence angle of less than 1.7 mrad, an output pulse of greater than 208 mJ, and a pulse width of approximately 10 ns, corresponding to a pulse peak power of approximately 20 MW. The laser array has a total output energy of 1.53 J at an electrical input of 93.3 J, corresponding to an overall electro-optical conversion efficiency of 1.64 % and an electro-optical slope efficiency of 3.17 %. Finally, laser array output pulses coded modulation in the space-power-time domains are achieved by electro-optical Q-switching. Therefore, the laser array provides the capability for programmable laser reconstruction in the space-power-time domains in a laser system for multipurpose applications, such as energy-tailored material processing, coded pulse laser ranging for improved signal-to-noise ratio (SNR), active optical remote sensing and scientific research. [ABSTRACT FROM AUTHOR]

Recently, compressing cipher images by using compressive sensing (CS) has attracted a lot of attention. However, the previous CS-based works cannot provide satisfactory compression performance. In this article, a cipher-image compression scheme based on CS and interweaving permutation is proposed to address this concern. Before image compression, the nature image is down-sampled to generate a lot of patches by using interweaving permutation firstly and then each patch is encrypted by a scrambling matrix, where each patch is a down-sampled image. In this way, the encrypted patches are highly correlated from one to each other since they preserve the correlation of the original patches. Therefore, we can encode the cipher image by employing CS and differential pulse-code modulation (DPCM) in an efficient way. To reconstruct the image effectively, an iterative shrinkage-thresholding (IST) algorithm is developed. Compared with the previous CS-based works, our scheme achieves better ratio-distortion (R-D) performance. [ABSTRACT FROM AUTHOR]

Pulsed laser systems for long range target detection process multiple pulses to increase signal-to-noise ratio SNR from that of a single pulse. Unipolar on–off keying (OOK) periodic pulse modulation codes are appropriate for an incoherent system. Mismatched filters for cross-correlation with codes are solutions to exactly determined linear equations, so all zero sidelobes are realized for any nonsingular set of equations and codes that are not all zeros. Therefore, maximum SNR is proposed as the criterion for code-filter pair adoption at a given code length. The fast solution of the mismatched filtering circulant equations allows all codes for a set of balancing values [differences of numbers of on (ones) and off (zeros)] to be tested for odd code lengths up through 33. M-sequences and Legendre codes of prime lengths one less than a multiple of four and an excess of one more on than off lead to optimal SNR code-filter pairs. These Legendre codes are suggested for longer codes since they are easily constructed. Code-filter pairs that optimize SNR for a given code length and balancing values of ±1, ±3, ±5, and ±7 are reported. For a balancing value of –1, a new set of codes with corresponding two-value filters is found. [ABSTRACT FROM AUTHOR]

The on-board telemetry system of an aerospace vehicle sends the vehicle performance parameters to the ground receiving station at all instances of its trajectory. During the course of its trajectory, the communication channel of a long range vehicle, experiences various phenomena such as plume attenuation, stage separation, manoeuvring of a vehicle and RF blackout, causing loss of valuable telemetry data. The loss of communication link is inevitable due to these harsh conditions even when using the space diversity of ground receiving systems. Conventional telemetry systems do not provide redundant data for long range aerospace vehicles. This research work proposes an innovative delay data transmission, frame switchover and multiple frames data transmission schemes to improve the availability of telemetry data at ground receiving stations. The proposed innovative schemes are modelled using VHDL and extensive simulations have been performed to validate the results. The functionally simulated net list has been synthesised with 130 nm ACTEL flash based FPGA and verified on telemetry hardware. [ABSTRACT FROM AUTHOR]

This paper describes a new type of digital hydraulic valve run by two servo motors. Digital hydraulics is a cuttingedge technology, which saves more exhausted energy than conventional hydraulic valves. It includes conventional valves, but its working principle is different. Similar or different size valves constitute a digital hydraulic valve assembly. When the assigned valves are opened, a certain amount of flow is obtained from the output of the valve assembly. To control a digital hydraulic valve, Pulse Number Modulation (PNM) Control technique is used for equal valve flow rates, while Pulse Code Modulation (PCM) is used for different valve flow rates. Valves are exerted by independently launched electric coils. Previous studies used controller board and external power booster circuits for coils. In this study, a new type of digital hydraulic valve is designed, manufactured, and tested with the PNM method. The studied valve body has two different valve groups. Every group includes 16 equal valves and 1 camshaft rotated by 1 servo motor. The servo motors are controlled by a PLC. The calculated performance index is found to be 5.1ms which is similar to the results of previous studies. The experimental results showed that the cam and servo motor controlled digital hydraulics is applicable to variable speed control hydraulic systems. [ABSTRACT FROM AUTHOR]

Compressive Video Sensing (CVS) is the video coding framework that uses compressive sensing (CS) theory into video codec to reduce the burden of encoding. Various existing methods are developed for CVS, but enhancing reconstruction speed and reconstruction quality remains a great challenge in video compression. Hence, an optimal method is developed using the proposed Differential Pulse Code Modulation+Conditional Autoregressive-Salp Swarm (DPCM+CA-SS) model for CVS system by considering the characteristics of CVS frame. The spatial redundancy of video frames is explored by partitioning the video frames into several blocks such that each block is measured using the measurement matrix. The measurement vectors are quantized using DPCM. The key frames are compressed into bits using Huffman coding, and the packet is transmitted to the decoder side. The temporal redundancy of CVS model is explored by encoding the frames using CA-SS-based prediction model to achieve Motion Aligned (MA) optimal reconstruction. However, the proposed CA-SS is designed by the integration of Conditional Autoregressive Value at Risk (CAViaR) and Salp Swarm Algorithm (SSA), respectively. However, the proposed DPCM+CA-SS obtained maximum PSNR and SSIM of 39.6649 db and 0.9120, and the minimum total time of 4.9523 s, respectively. [ABSTRACT FROM AUTHOR]

Nuclear Magnetic Resonance (NMR) spectroscopy is an analytical technique commonly used across the natural sciences that works upon the detection of magnetically spin-aligned atomic nuclei resonating with an externally applied radio source. This work presents an overview of music created using NMR data and outlines principles for its use in composition. Methods for the sonification and musical interpretation of NMR spectra are demonstrated and opportunities for its development as a musical technique are identified. Abbreviations: 12-TET: Twelve-Tone Equal Temperament; ADC: Analogue to Digital Converter; COSY: Correlation Spectroscopy; FID: Free Induction Decay; FT: Fourier Transform; NMR: Nuclear Magnetic Resonance; PCM: Pulse Code Modulation; PPM: Parts per million; SNR: Signal-to-noise ratio; TMS: Tetramethylsilane [ABSTRACT FROM AUTHOR]

This article presents a voltage-controlled oscillator (VCO)-based analog front end (AFE) for ExG readout applications with both a wide dynamic range (DR) and high linearity. By using a differential pulse code modulation (DPCM) technique, VCO non-linearity is mitigated by operating the VCO in the small-signal linear regime. To minimize power consumption from the power-hungry gain error calibration, the effect of VCO gain variation within the DPCM loop is investigated, leading to a calibration-free DPCM via a $\Delta \Sigma $ truncator. At the circuit level, a coarse–fine phase decoding scheme is proposed to increase signal-to-quantization-noise ratio (SQNR) while avoiding metastability issues. Fabricated in 65 nm, the AFE occupies an area of 0.056 mm2. It achieves 94.2-dB SNDR and 95.1-dB DR in 500 Hz of bandwidth while dissipating 1.68- $\mu \text{W}$ power from a single 0.8-V supply, yielding a Schreier FoM of 178.9 dB. Importantly, the techniques enable a virtually distortion-less spectrum with a noise-floor limited spurious-free dynamic range (SFDR) of 128 dB. In addition, the AFE is validated with ECG and EOG recording, demonstrating complete signal capturing in the presence of motion/stimulation artifacts. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In an increasingly connected world, consumer video experiences have diversified away from traditional broadcast video into new applications with increased use of non-camera-captured content such as computer screen desktop recordings or animations created by computer rendering, collectively referred to as screen content. There has also been increased use of graphics and character content that is rendered and mixed or overlaid together with camera-generated content. The emerging Versatile Video Coding (VVC) standard, in its first version, addresses this market change by the specification of low-level coding tools suitable for screen content. This is in contrast to its predecessor, the High Efficiency Video Coding (HEVC) standard, where highly efficient screen content support is only available in extension profiles of its version 4. This paper describes the screen content support and the five main low-level screen content coding tools in VVC: transform skip residual coding (TSRC), block-based differential pulse-code modulation (BDPCM), intra block copy (IBC), adaptive color transform (ACT), and the palette mode. The specification of these coding tools in the first version of VVC enables the VVC reference software implementation (VTM) to achieve average bit-rate savings of about 41% to 61% relative to the HEVC test model (HM) reference software implementation using the Main 10 profile for 4:2:0 screen content test sequences. Compared to the HM using the Screen-Extended Main 10 profile and the same 4:2:0 test sequences, the VTM provides about 19% to 25% bit-rate savings. The same comparison with 4:4:4 test sequences revealed bit-rate savings of about 13% to 27% for $Y'C_{B}C_{R}$ and of about 6% to 14% for $R'G'B'$ screen content. Relative to the HM without the HEVC version 4 screen content coding extensions, the bit-rate savings for 4:4:4 test sequences are about 33% to 64% for $Y'C_{B}C_{R}$ and 43% to 66% for $R'G'B'$ screen content. [ABSTRACT FROM AUTHOR]

In the conventional airborne telemetry system, the pre‐modulation filter with a multi‐pole active Bessel filter is preferred to use in Pulse Code Modulator (PCM)/FM transmission. In the existing system, it is not possible to change the cut‐off frequency for different data rates dynamically as required in the launch scenario of a long‐range aerospace vehicle. In general, aerospace vehicle has multiple propellant stages to travel a desired trajectory path. Each stage gets separated from the vehicle at different instances. Each stage measurement plan is defined and correspondingly the PCM format is generated with an optimum data rate. Hence, the telemetry system is required to transmit variable data rates at various instances of a long‐range aerospace vehicle from launch point to end point of a vehicle. This can be addressed by designing a dynamically tuneable pre‐modulation (DTPM) filter. Here, a suitable DTPM filter scheme is proposed to mitigate variable data rate transmission in the telemetry system. The scheme is analysed as per IRIG‐106 standard and simulated using MATLAB. The same has been modelled using VHDL and implemented targeting 28 nm technology Xilinx Zynq FPGA device. [ABSTRACT FROM AUTHOR]

In this paper, a simple color image compression system has been proposed using image signal decomposition. Where, the RGB image color band is converted to the less correlated YUV color model and the pixel value (magnitude) in each band is decomposed into 2-values; most and least significant. According to the importance of the most significant value (MSV) that influenced by any simply modification happened, an adaptive lossless image compression system is proposed using bit plane (BP) slicing, delta pulse code modulation (Delta PCM), adaptive quadtree (QT) partitioning followed by an adaptive shift encoder. On the other hand, a lossy compression system is introduced to handle the least significant value (LSV), it is based on an adaptive, error bounded coding system, and it uses the DCT compression scheme. The performance of the developed compression system was analyzed and compared with those attained from the universal standard JPEG, and the results of applying the proposed system indicated its performance is comparable or better than that of the JPEG standards. [ABSTRACT FROM AUTHOR]

With the wide applications of dual‐rotor flux‐modulation machines for the growing wind power generations, research activities for the control of dual‐rotor flux‐modulation machines are intensified in recent years. Most of the existing control schemes are based on indirect measurements of the d‐axis inductance, the q‐axis inductance and the stator resistance to achieve high torque density and low torque ripple for the dual‐rotor flux‐modulation machines. However, conventional measurements of the d‐axis inductance, the q‐axis inductance and the stator resistance may suffer from (i) low accuracy and (ii) additional sensor costs. To this end, an adaptive differential evolution algorithm is proposed to identify the machine parameters by considering the magnetic saturation and cross‐coupling issue at low rotational speed of dual‐rotor flux‐modulation machines. Finite element analysis is adopted in simulation to preliminarily monitor the actual machine parameter values based on the length and cross section area of the conductor and inductance matrix computation. Both simulation and experimental results reveal that the adopted adaptive differential evolution algorithm can identify the three parameters more steadily and accurately than the conventional genetic algorithm. [ABSTRACT FROM AUTHOR]

Signal processing techniques incorporated with data compression processes enrich the signals and boost up storage efficiency and transmission reliability. Transmitting uncompressed original data consume wide bandwidth, which increases transmission time and leads to data hammering. These limitations enforce to look for strategic data compression techniques. Lossless compression techniques are requisite where it is important that the original and the decompressed data should be identical or where deviations from the original data would lead to catastrophic consequences, especially in biomedical signal analysis and diagnostics. For which, the input signal preprocessed with differential pulse code modulation (DPCM) reduces the interchannel dependencies to get the desired output. A whole array of unique compression techniques are being utilized in the compression process. The combination of (K‐means clustering, arithmetic encoding [AE], Huffman encoding [HE]) clustering and coding compression techniques are analyzed using electro cardiogram (ECG) and electroencephalogram (EEG) signals. The proposed method employs k‐means clustering combined with Huffman encoding (DiKHE) and k‐means clustering combined with arithmetic encoding (DiKAE) individually. Compression ratio (CR) is analyzed with these combinations of compression techniques for various cluster size K (K = 2,3,4,5,6). A maximum CR of 6.03144 and 4.54126 is obtained for ECG and EEG signals respectively. The compressions based on these techniques are efficient since the compressed signal is reconstructed perfectly as it matches exactly with the original signal. [ABSTRACT FROM AUTHOR]

The adaptive communication systems require a good estimation technique to offer beneficial performances. In this work, a new robust estimation algorithm based on a non-quadratic error function (RNQ) was proposed for Bit Error Rate (BER) reduction, and improving of the spectral efficiency (SE) and transmission throughput in Adaptive Modulation and Coding-Coded Orthogonal Frequency Division Multiplexing (AMC-COFDM) systems. Also, this technique is compared to the Normalised Least Mean Square (NLMS) estimation method. The obtained results show clearly that the estimation method based on the RNQ algorithm is very efficient in term of the convergence speed and minimum average error and works very satisfactorily. [ABSTRACT FROM AUTHOR]

In this paper, a simple image compression algorithm is proposed for wireless capsule endoscopy. The proposed algorithm consists of new simplified YUV colour space, corner clipping, uniform quantization, subsampling, differential pulse code modulation and Golomb Rice code. Simplified YUV colour space is proposed based on special nature of endoscopic images and provide good results. The quantization and subsampling are used as lossy compression techniques and fixed Golomb-Rice code is used to encode residual value obtained after differential pulse code modulation operation. Here performance of different combination of quantization and subsampling techniques are analyzed based combination along with the proposed compression algorithm provides compression ratio of 89.3% and peak signal noise ratio of 45.1. the proposed algorithm provided better results as compared to various reported algorithms in literature in term of CR and PSNR. [ABSTRACT FROM AUTHOR]

Music rhythm detection and tracking is an important part of the music comprehension system and visualization system. The music signal is subjected to a short-time Fourier transform to obtain the frequency spectrum. According to the perception characteristics of the human auditory system, the spectrum amplitude is logarithmically processed, and the endpoint intensity curve and the phase information of the peak value are output through half-wave rectification. The Pulse Code Modulation (PCM) characteristic value is extracted according to the autocorrelation characteristic of the endpoint intensity curve. This article proposes a rhythm detection algorithm based on multipath search and cluster analysis; that is, based on the clustering algorithm, it absorbs the idea of multipath tracking and proposes its own detection and tracking algorithm. It overcomes the weakness of the clustering algorithm that needs to use Musical Instrument Digital Interface (MIDI) auxiliary input to achieve the desired effect. This algorithm completely uses the PCM signal as the input, which is more robust than the clustering algorithm. The whole process is carried out in the time domain, and the amount of calculation is much smaller than the frequency domain calculation of multipath tracking, and the linear relationship with the rhythm of the music is much better than the filter bank algorithm. This algorithm can successfully detect the rhythm of the music with a strong sense of rhythm and can track the specific position of the rhythm point. [ABSTRACT FROM AUTHOR]

This article presents a high-dynamic-range (DR) voltage-controlled oscillator (VCO)-based front end for sensor readout applications. Unlike conventional VCO-based quantizers, which suffer from large voltage-to-frequency non-linearities, the proposed design leverages differential pulse-code modulation (DPCM) from compression theory to substantially reduce the amplitude of the signal incident to the VCO quantizer, thereby achieving an ultra-low total harmonic distortion (THD) of −112 dB. In addition, background digital gain calibration is employed to overcome gain deviation of the VCO, thus ensuring a robust design. Together with dynamic element matching (DEM), the techniques enable a high DR using only the first-order noise shaping inherent in VCO-based quantizers and a moderate 32 × oversampling ratio. Fabricated in 65 nm, the sensor front end consumes 3.2-μW power and achieves an SNDR of 89 dB and a DR of 94 dB in 500 Hz of bandwidth. Together with a 1.18-μVrms integrated input-referred noise, it achieves a noise efficiency factor (NEF) of 4 and a Schreier FoM of 171 dB. [ABSTRACT FROM AUTHOR]

Ultra-stable room-sized environmental chambers may involve significant power variations leading to hysteresis and nonlinearities of the stabilization system. This paper describes utilization of a pulse code modulation control which significantly reduces observed nonlinearity of the chamber actuation system. Stability of environmental conditions for temperature Δ T = ± 25 mK (15–35 °C dynamic range), relative humidity Δ R h = ± 0. 1 % (3%–95% dynamic range), and pressure Δ P = ± 12 Pa (± 500 Pa dynamic range) was achieved within 27 m 3 chamber volume, which is two orders of magnitude better than the corresponding stabilization achievable using a standard linear proportional–integral–derivative (PID) controller. Utilizing this chamber we have demonstrated two orders of magnitude improvement of the operational relative frequency stability of ultrastable quartz oscillators (USO), reaching 2 × 1 0 − 13 stability at 1- 1 0 5 s averaging time. • The chamber allow the development of instruments before the environment is available. • The chambers simulate conditions to test the failure rates of the novel instruments. • Control of the environmental factors is the key to qualify the source of failure. • The chamber is tuned to qualify atomic clocks, masers, oscillators, frequency units. • A pulse code modulation control reduces nonlinearity of the chamber actuation system. [ABSTRACT FROM AUTHOR]

Video compression has great significance in the communication of motion pictures. Video compression techniques try to remove the different types of redundancy within or between video sequences. In the temporal domain, the video compression techniques remove the redundancies between the highly correlated consequence frames of the video. In the spatial domain, the video compression techniques remove the redundancies between the highly correlated consequence pixels (samples) in the same frame. Evolving neural-networks based video coding research efforts are focused on improving existing video codecs by performing better predictions that are incorporated within the same codec framework or holistic methods of end-to-end video compression schemes. Current neural network-based video compression adapts static codebook to achieve compression that leads to learning inability from new samples. This paper proposes a modified video compression model that adapts the genetic algorithm to build an optimal codebook for adaptive vector quantization that is used as an activation function inside the neural network's hidden layer. Background subtraction algorithm is employed to extract motion objects within frames to generate the context-based initial codebook. Furthermore, Differential Pulse Code Modulation (DPCM) is utilized for lossless compression of significant wavelet coefficients; whereas low energy coefficients are lossy compressed using Learning Vector Quantization (LVQ) neural networks. Finally, Run Length Encoding (RLE) is engaged to encode the quantized coefficients to achieve a higher compression ratio. Experiments have proven the system's ability to achieve higher compression ratio with acceptable efficiency measured by PSNR. [ABSTRACT FROM AUTHOR]

The present experimental work aims to improve the performance of solar-powered tubular direct contact membrane distillation (TDCMD) systems. To investigate this idea, the membrane distillation system was integrated with thermal energy storage mediums and the evaporative cooler. The novelty of the present configuration is addition the energy storage mediums (phase change materials PCM) which represent the energy source to extend the water production time after sunset with high rates, as well as, improve the productivity in the period of low solar intensity before sunset. To obtain the influences of PCM on the performance of solar-assisted TDCMD with an evaporative cooler, the present configuration was tested first without PCM and again with utilizing the PCM within different test days under Egyptian climatic conditions. The experimental results show that as increases the rate of feed saltwater from 12 to 16 l/min, the accumulated productivity of solar-assisted TDCMD with evaporative cooler varying between 28.9 and 35.67 l/day while additional the PCM augments the productivity to 41.38–47.48 l/day, representing 33.11–43.18% enhancement in the productivity. Also, the gain output ratio of solar-assisted TDCMD with evaporative cooler varying between 0.77 and 0.93 while additional the PCM augments the gain output ratio to 1.123–1.25, representing 34.4–45.84% enhancement in the gain output ratio. • Thermal storage mediums (PCM) have a great influence on the performance of TDCMD. • Novelty of this configuration is addition the PCM to the solar-assisted TDCMD with evaporative cooler. • PCM represent the energy source to extend the water production time after sunset with high rates. • Improvement in distillate water production of TDCMD for utilizing the PCM reached 47.48%. • Improvement in gain output ratio of TDCMD for utilizing the PCM reached 45.84%. [ABSTRACT FROM AUTHOR]

Sparse representation provides an efficient way for the compression of hyperspectral images in the literature. In this work, an improved version of the Spectral-Spatial Adaptive Sparse Representation (SSASR), Modified SSASR (MSSASR), is proposed for hyperspectral image compression. In the first step of the proposed method, superpixel maps are generated for adaptive spatio-spectral representation. Then, the best possible dictionary is computed for the representation of the data. Afterwards, sparse coefficients are determined depending on the dictionary by Simultaneous Orthogonal Matching Pursuit (SOMP) method. In the final step, the dictionary and sparse coefficients are encoded by quantization and entropy encoding. This paper has the following novelties: modified dictionary learning step, new ordering scheme and Differential Pulse Code Modulation (DPCM) usage. Owing to modified dictionary learning, the sparse coefficients can be represented more compact than traditional SSASR. By using of new ordering scheme, it is not needed to send the superpixel map as side information. Moreover, DCPM usage lowers the magnitudes of sparse coefficients. Thanks to these modifications, the proposed method achieves an important improvement on compression performance. In the experimental results, the proposed method is compared with PCA+JPEG2000, DWT+JPEG2000, 3D-SPECK, 3D-TARP and SSASR methods on Indian Pines, Washington DC Mall, Jasper Ridge and Moffett Field scenes. The evaluation is carried out not only using distance and similarity metrics, namely, signal-to-noise ratio, mean spectral angle and mean spectral correlation metrics but also computation times. Additionally, reconstruction quality in anomaly regions is also used for comparison. Experimental results show that the proposed method outperforms the other compression methods in terms of quality metrics and anomaly preserving performance. [ABSTRACT FROM AUTHOR]

• Experimentally validated 2D transient numerical model for PV/PCM is developed. • New non-rectangular designs with strategic mass distribution of PCM are proposed. • Melting rate enhanced due to convection domination and delayed quasi-steady regime. • Proposed design exhibits better thermo-electric performance. Encapsulated phase change materials (PCM) are used to improve the electrical efficiency of photovoltaic (PV) panel by absorbing waste heat during the melting process. Previous investigators reported the melting process of PCM in a rectangular encapsulation and observed four transient regimes of heat transfer in sequence as: conduction, mixed conduction-convection, quasi-steady convection and solid-shrinking regimes. For higher heat extraction from the PV panel, longer duration of quasi-steady convection regime is desirable. However, this steady regime is suppressed in the rectangular PCM enclosure due to the nature of natural convection and consequently, the melting rate of the PCM is arrested. In this paper, we report on electrical and thermal performance of non-rectangular PCM integrated PV panels using an experimentally validated numerical model that enhances the quasi-steady regime by more than 100% compared to the conventional rectangular design. The strategic mass distribution of PCM for better thermal management was achieved with encapsulation designs having profile of right wall varying as y = a x - b 1 / n , w i t h n = 1 (l i n e a r) , 2 (p a r a b o l i c) a n d 3 (c u b i c) with different lower thickness ratio. Compared to conventional design, the proposed design increased the PCM melting rate by 17% due to which PV cell temperature dropped by 11.5% and consequently, electrical conversion efficiency approaches to 12%. [ABSTRACT FROM AUTHOR]

• A wall system composed by a CO 2 -filled transparent insulation and PCM is evaluated. • A detailed mathematical model for thermal performance evaluation has been developed. • The proposed model has been validated with outputs from complex simulation tools. • The wall system has been modelled considering a Mexico City office as case study. • CO 2 as a gas filling insulation option presents the best technoeconomic potential. Novel thermal insulation materials and wall configurations have the potential to play a major role in reducing energy demand and carbon emissions from the building sector. In this study, a passive heating wall system composed by a CO 2 -filled transparent thermal insulation (TTI) and an organic phase change material (PCM), and a passive cooling system composed by a Tromble Wall with nano-film and a CO 2 -filled TTI are proposed and evaluated. The aim is to present a detailed analytical model for rapidly calculating thermal performance of the proposed wall configurations. As case study, a 108 m2 south façade of a building located in Mexico has been used. Outputs suggest that as a passive heating measure, the system has the potential to supply heat in the order of 118 W, 126 W, 134 W, and 157 W, during the months of December, January, February, and March respectively. Additionally, thermal performance and air velocity simulations suggest that for the heating case, considering an outdoor and indoor temperature conditions of 0 °C and 21 °C respectively, the internal layer surface reaches a temperature of 9.2 °C; while for the cooling case, considering outdoor and indoor temperature conditions of 25 °C and 21 °C respectively, it reaches 22.5 °C with a maximum indoor air velocity of 0.5 m/s. Compared to other gases, CO 2 could hold a greater potential due to its low thermal conductivity and capital costs. Large-scale implementation of such systems could make the building sector an interesting option as an artificial sink for carbon storage. [ABSTRACT FROM AUTHOR]