Graphical vector description of sampling weights in phase-detecting algorithms

In this day of digitalization, you can work within the technology of optics without having to fully understand the science behind it. However, for those who wish to master the science, rather than merely be its servant, it's essential to learn the nuances, such as those involved with studying fringe patterns produced by optical testing interferometers.When Interferogram Analysis for Optical Testing originally came to print, it filled the need for an authoritative reference on this aspect of fringe analysis. That it was also exceptionally current and highly accessible made its arrival even more relevant. Of course, any book on something as cutting edge as interferogram analysis, no matter how insightful, isn't going to stay relevant forever. The second edition of Interferogram Analysis for Optical Testing is designed to meet the needs of all those involved or wanting to become involved in this area of advanced optical engineering. For those new to the science, it provides the necessary fundamentals, including basic computational methods for studying fringe patterns. For those with deeper experience, it fills in the gaps and adds the information necessary to complete and update one's education. Written by the most experienced researchers in optical testing, this text discusses classical and innovative fringe analysis, principles of Fourier theory, digital image filtering, phase detection algorithms, and aspheric wavelength testing. It also explains how to assess wavefront deformation by calculating slope and local average curvature.

This paper presents a synchronous detection with Fourier analysis (SDFA) method. The proposed method is used to calculate the reference current of single-phase shunt active power filters. The SDFA method is operated bases on a synchronous detection (SD) and the sliding window with Fourier analysis (SWFA) technique. The harmonic elimination in single-phase power system is considered in this paper. The performance comparison of the SD and SDFA methods is also presented. The simulation results by using the Simulink program confirm that the SDFA method can provide the better performance compared with the SD method. Furthermore, the total harmonic distortion percentage (%THD) of the source current after compensation is satisfied under the IEEE std 519–2014.

Can Deep Learning Algorithms Help Identify Surgical Workflow and Techniques?

Wireless capsule endoscopes take and send photos of the human digestive tract, which are used for medical diagnosis. The capsule’s location enables exact identification of the regions with lesions. This can be carried out by analyzing the parameters of the electromagnetic wave received from the capsule. Because the human body is a complex heterogeneous environment that impacts the propagation of wireless signals, determining the distance between the transmitter and the receiver based on the received power level is challenging. An enhanced approach of identifying the location of endoscope capsules using a wireless signal phase detection algorithm is presented in this paper. For each capsule position, this technique uses adaptive estimation of human body model permittivity. This approach was tested using computer simulations in Remcom XFdtd software using a numerical, heterogeneous human body model, as well as measurements with physical phantom. The type of transmitting antenna employed in the capsule also has a significant impact on the suggested localization method’s accuracy. As a result, the helical antenna, which is smaller than the dipole, was chosen as the signal’s source. For both the numerical and physical phantom studies, the proposed technique with adaptive body model enhances localization accuracy by roughly 30%.

Phase detection system based on digital signal processing in millimeter wave interferometer for fusion plasma diagnostics

The main objective of this work is to make an algorithm to detect onset and offset of stance and swing phase of human gait cycle. In order to proceed, the signal from the force sensors (placed underneath each foot) were first divided according to the fundamental period by auto-correlation. This ensures that each period contains a full stance phase and two fragmented swing phases. After this step, Short Time Fourier transform has been performed on each period of the signal to detect the initial search point (highest DC value) on the stance phase. Then by judging the width and slope of the straight line from changing search points on the signal to a changing destination point (starting from the minimum or maximum time value) of the graph the onset and offset of the stance and swing phase has been detected. The changing search point has small distance from the previous one, if the slope of the signal is small, but the distance increases with the increasing change of slope of the signal. The destination point changes with the change of slope of the straight line. This algorithm has been applied to the signals in the database of Parkinsons disease, which shows a success rate of more than 90%.

In this paper, robust and efficient frame detection, symbol timing synchronization, frequency synchronization and cell ID detection techniques suitable for IEEE 802.16d/e wireless MAN system are proposed. The proposed timing synchronization algorithm exploits periodicity in preamble and also cyclic prefix (CP) periodicity to find the orthogonal frequency division multiplexing (OFDM) symbol boundary. This algorithm is a novel combination of preamble and CP self-correlation information to achieve symbol timing synchronization. The proposed frequency synchronization algorithm also uses self-correlation result of preamble and CP. Cell ID detection is done using the cross correlation properties of the preamble. The proposed synchronization algorithms can do synchronization even under low SNRs, high frequency offset, and multipath fading channels.

This paper proposed a new AC signal detection method based on variable N synchronous sampling to solve the problems on the harmonic detection and analysis of periodic sin waveform in power grid. Comparing with the traditional fixed N synchronous sampling detection in which the number of sampled data is constant in a period, the key difference of the new method is that the period of sampling points as an unknown variable N, to suit for signal detection in the actual situation. Through the acquisition processing and analysis of data detected, the entire period of synchronous sampling could be obtained to overcome the effects of spectral leakage and fence effect.

In order to improve the quality of wireless English multimedia communication, according to the characteristics of space multimedia communication environment and communication equipment, this paper proposes a wireless English synchronous QoS control algorithm with low complexity and easy implementation. Using RTCPSRRTP timestamp and NTP absolute timestamp, the wireless English RTP timestamp is mapped to the same absolute reference clock (sender system time) respectively, and the wireless English synchronization detection decision rule is established according to the synchronization QoS performance requirements between wireless English media. Wireless English synchronization control system model at the receiver. At the receiving end, the wireless English stream is the main media stream and the video stream is the slave media stream. The synchronization detection and judgment is implemented in real time before the video frame is played. The synchronization between audio and video media is realized by corresponding synchronization control of wireless English playback. State space model reflects all the information of system dynamic behavior and is a complete description of system behavior. The state space model has a wide range of applications. It is not only suitable for SISO linear constant systems, but also suitable for nonlinear systems, time-varying systems, MIMO systems and stochastic systems. The more outstanding advantage is that the state space model adopts local calculation and uses the state variables inside the system to describe its dynamic characteristics. This property of local calculation not only greatly simplifies the mathematical expression of multi-dimensional system, but also facilitates the analysis and research of the system. The air link rate of the wireless transceiver is set to 512Kbps. The video is encoded based on H.264 and the audio is encoded based on G.729 Speech coding standard. Compared with the wireless English media synchronization control algorithm based on RTP / RTCP, the results show that the RMSE value after adopting the synchronization algorithm in this paper is reduced by 60.09% and 77.69% at most; Compared with the wireless English media synchronization control algorithm based on RTP / RTCP, the synchronization performance of this algorithm is better than the wireless English media synchronization control algorithm. The RMSE value is reduced by 2% on average and 5.2% at most. In addition, the synchronization control algorithm between wireless English media performs synchronization control by losing frames or pausing decoding before video decoding at the receiver, which affects the quality of wireless English video decoding and reconstruction.

NMR is a unique methodology for obtaining information about the conformational dynamics of proteins in heterogeneous biomolecular systems. In various NMR methods, such as transferred cross-saturation, relaxation dispersion, and paramagnetic relaxation enhancement experiments, fast determination of the signal intensity ratios in the NMR spectra with high accuracy is required for analyses of targets with low yields and stabilities. However, conventional methods for the reconstruction of spectra from undersampled time-domain data, such as linear prediction, spectroscopy with integration of frequency and time domain, and analysis of Fourier, and compressed sensing were not effective for the accurate determination of the signal intensity ratios of the crowded two-dimensional spectra of proteins. Here, we developed an NMR spectra reconstruction method, “conservation of experimental data in analysis of Fourier” (Co-ANAFOR), to reconstruct the crowded spectra from the undersampled time-domain data. The number of sampling points required for the transferred cross-saturation experiments between membrane proteins, photosystem I and cytochrome b 6 f, and their ligand, plastocyanin, with Co-ANAFOR was half of that needed for linear prediction, and the peak height reduction ratios of the spectra reconstructed from truncated time-domain data by Co-ANAFOR were more accurate than those reconstructed from non-uniformly sampled data by compressed sensing.Electronic supplementary materialThe online version of this article (doi:10.1007/s10858-015-9908-9) contains supplementary material, which is available to authorized users.

The next generation digital TV (DTV) broadcast, namely Advanced Television System Committee (ATSC) 3.0, relies on substantial single frequency networks (SFN), each of which requires a studio to transmitter link (STL) to transmit data from the broadcast gateway (BG), leading to significant construction costs. Therefore, the wireless in-band distribution link (IDL) technology is proposed, which uses layered-division multiplexing (LDM) to transmit the STL data via wireless links from the BG to the SFN transmitters within the same spectrum as the broadcast services. In this paper, we propose the time synchronization and signal detection algorithm for wireless IDL systems with both unicast and broadcast signals. We introduce two multiplexing schemes, N-LDM and 3-LDM, and demonstrate their superiority over traditional frequency division multiplexing (FDM). To overcome the challenge of multi-access interference and synchronization errors caused by multipath, we develop a unique word (UW) design algorithm for transmitted signals and a double threshold correlation detection algorithm (DTCDA) that outperforms traditional ones. We employ a second threshold to enhance detection performance at low signal-to-noise ratios, and utilizes successive interference cancellation (SIC) to mitigate multiple-access interference. More importantly, our approach requires no knowledge of the unicast user number or channel state information. Simulation results validate the effectiveness of the proposed scheme.

Photon counting (PhC) is an effective detection technology for underwater optical wireless communication (OWC) systems. The presence of signal-dependent Poisson shot noise and asynchronous multi-user interference (MUI) complicates the processing of received data signals, hindering the effective signal detection of PhC OWC systems. This paper proposes a novel iterative signal detection method in grant-free, multi-user, underwater PhC OWC systems with signal-dependent Poisson shot noise. We first introduce a new synchronization algorithm with a unique frame structure design. The algorithm performs active user identification and transmission delay estimation. Specifically, the estimation is performed first on a user group basis and then at the individual user level with reduced complexity and latency.We also develop a nonlinear iterative multi-user detection (MUD) algorithm that utilizes a detection window for each user to identify interfering symbols and estimate MUI on a slot-by-slot basis, followed by maximum <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a-posteriori</i> probability detection of user signals. Simulations demonstrate that our scheme achieves bit error rates comparable to scenarios with transmission delays known and signal detection perfectly synchronized.

Die Serie Communications in Asteroseismology (CoAst) stellt eine international gefragte Plattform für wissenschaftliche Publikationen der neuesten Forschungsergebnisse auf dem Gebiet der Asteroseismologie dar. Forschungsgegenstand der Asteroseismologie sind veränderliche und pulsierende Sterne. Neben den halbjährlich erscheinenden regulären Ausgaben mit Beiträgen aus der laufenden Forschung werden auch Sonderausgaben für Konferenzberichte bzw. Programmhandbücher herausgegeben. Volume 153 beinhaltet eine Vielzahl von Arbeiten mit Ergebnissen aus erdgebundenen und satellitengestüzten Beobachtungen pulsierender Sterne sowie über den Vergleich mit theoretischen Modellen. Erstmals berichtet auch das von der EU eingerichtete Forschungsnetzwerk HELAS - European Helio- and Asteroseismology Network - über neue Instrumente und Strukturen für den Daten- und Wissensaustausch unter Astronomen.

In recent years, simulation has become an essential tool for planning, designing, and managing terminal operations. Simulation modeling of various aspects related to the dynamic nature of the pedestrian/passenger behavior within a transport terminal can effectively assist in the analysis, evaluation, emergency response planning, and decision support phases of the terminal's operation. In this paper, the development of an object‐oriented environment that enables both the graphical description and simulation of pedestrian traffic flows at the microscopic level is discussed. The simulation environment provides generation capabilities so that a terminal station model is directly formed on the basis of preconstructed component models. Essential experimentation capabilities, including graphical representation, are provided for pedestrian‐oriented and system‐oriented measures of interest with explicit emphasis on the level of service. A case study for a 4–level station in the new Athens subway system is also used to demonstrate the potential and functionality of the simulation environment.

MIMO-OFDM is currently being considered as a promising technology for future wideband wireless systems. Meanwhile, the detection of MIMO-OFDM system forms one of the most intensive tasks in baseband signal processing. There have been a great number of algorithms proposed for MIMO-OFDM detection. This paper investigates the real-time implementation of MIMO OFDM systems using programmable multi-SIMD (single instruction multiple data) processor targeting for software defined radio. We analyze the computational characteristic and cost of major algorithms of LPF, symbol synchronization, OFDM modulation, channel estimation and MIMO detection of a 4x4 MIMO-OFDM system based on 3GPP-LTE R-12 standard. The evaluation and implementation results show that our SDR architecture supports 300Mbps LTE system with 20MHz bandwidth. Finally, we discuss the architecture perspective of our SDR processor for future wireless communication standards with higher throughput.KeywordsMIMO-OFDMMulti-SIMDSDR3GPP-LTE