Deterioration Of Signals Research Articles

Demonstration and optimization of coherent Doppler wind LiDAR with low sampling resolution

A low sampling resolution scheme for coherent Doppler wind LiDAR (CDWL) is proposed. The CDWL offers advantages in precision and detection resolution but suffers from the requirement of high-speed data acquisition (DAQ) with high sampling resolution, such as 12- or 14-bit, which leads to an increase of the computational complexity and the system cost. The use of a DAQ system with lower sampling resolution can provide a solution to mitigate this problem. The feasibility of the proposed scheme is validated by simulations and experiments. The detection performance can be greatly affected by the quantization interval selected during sampling. It is shown that the optimal quantization interval exists and only depends on the carrier-to-noise ratio (CNR), and the optimal quantization intervals of several sampling resolutions are given at different CNRs. With the given optimal quantization configuration, the low sampling resolution data can be used for reliable wind field measurements. For long-distance detection with a CNR lower than −13dB, the CNR deterioration of 1-bit, 2-bit, 3-bit, and 4-bit signals can be as low as 2, 0.5, 0.2, and 0.1 dB.

Biocomposite silk fibroin hydrogel with stretchability, conductivity and biocompatibility for wireless strain sensor

As a natural biopolymer material, silk fibroin with unique mechanical properties can be used in the preparation of biocomposite hydrogels for strain sensors. But, the electromechanical properties of biocomposite hydrogel strain sensors are still insufficient, such as the deterioration of electrical signals and low sensitivity, which need to develop a hydrogel with a stable transmission network for electric conduction. Herein, a silk fibroin biocomposite hydrogel is prepared by incorporating tannic acid and MXene nanosheets into a polyacrylamide and silk fibroin double network. The electromechanical properties of hydrogels are improved by optimizing the proportion of material components. As a result, the double network structure and supramolecular interaction enhance the stretchability of hydrogels (692% fracture strain). The hydrogel also exhibits good biocompatibility and conductivity (0.85 S/m), which shows the application prospect in wearable sensors. The wireless strain sensor assembled by this biocomposite hydrogel presents good portability and sensing performance, such as high sensitivity (gauge factor = 6.04), wide working range (500% strain), and outstanding stability (1000 cycles at 100% strain). The results indicate that the hydrogel strain sensor can be used to monitor human body movement. The biocomposite hydrogel is expected to be applied in the field of wearable strain sensors, and this study can provide a new way for the design of flexible electronic materials.

Research on IQ Imbalance Error of Orthogonal Alternating Sampling

In the signal acquisition of complete orthogonal frequency alternating acquisition system, we need to transform the broadband input signal to baseband through analogue orthogonal demodulation. Thus, the IQ imbalance errors will inevitably exist, including amplitude imbalance error and phase imbalance error, resulting in distortion deterioration of reconstruction signals. This paper makes an in‐depth study on such IQ imbalance errors and mathematically deduces the mathematical expressions of imbalance errors and the spurious frequency distribution caused by them, which shows that the positions where the spurious signals appear are closely related to the frequency of input signal and the tuning frequency of analogue quadrature demodulation. Meanwhile, the amplitude and phase imbalance parameters of the channels I and Q are also calculated. Finally, the spurious effects caused by imbalance errors are verified by simulation experiment, and the verification results are consistent with the theoretical derivation results.

An alternating high‐low impedance common‐mode filter for differential striplines

The conventional quarter/half-wavelength common-mode filter (CMF) cannot work well for a differential stripline when there is no ground via. A new and effective via-free CMF design for the differential striplines is proposed in this study. An alternating high-low impedance structure is developed to increase the coupling between the stripline and the CMF, thus achieving a good filtering effect. A cascaded CMF design is further studied to enhance the stopband without deterioration of the differential signals. Both simulation and measurement results demonstrate the effectiveness of the proposed high-low impedance CMF. The significant advantage of the proposed CMF is its compactness and simplicity, which has almost no impact on the original layout of differential striplines.

Describing I2V Communication in Scenarios for Simulation-Based Safety Assessment of Truck Platooning

V2X communication plays an important role in the transition towards connected, cooperative, automated driving. Wireless communication enables instant information exchange between vehicles (V2V) to support, e.g., platooning, and between the infrastructure and vehicles (I2V) to inform vehicles on, e.g., the local speed limit information or the approach of an accident location. In the Horizon 2020 HEADSTART project, we have shown how to test V2V communication in a scenario-based safety assessment framework. Safety assessment aims to determine the impact on safety in the case of potentially critical scenarios, e.g., due to, or in parallel to deterioration of communication. In this study, we extend this methodology with the incorporation of I2V communication. The developed method allows us to treat V2V and I2V communication independently. We demonstrate the method in the use case of an Intelligent Speed Adaptation I2V-functionality for platooning trucks. The practical implementation of test descriptions that consider the potential deterioration of communication signals in the standardized OpenSCENARIO format is shown. The study illustrates how tests are performed in a hardware-in-the-loop setup specifically developed for testing platooning functions. The availability of a test method that is capable of dealing with V2X communication is an important step towards the implementation of type approval methods for Cooperative, Connected and Automated Mobility (CCAM) systems.

Phosphoinositide 3-Kinase Signaling in the Tumor Microenvironment: What Do We Need to Consider When Treating Chronic Lymphocytic Leukemia With PI3K Inhibitors?

Phosphoinositide 3-kinases (PI3Ks) and their downstream proteins constitute a signaling pathway that is involved in both normal cell growth and malignant transformation of cells. Under physiological conditions, PI3K signaling regulates various cellular functions such as apoptosis, survival, proliferation, and growth, depending on the extracellular signals. A deterioration of these extracellular signals caused by mutational damage in oncogenes or growth factor receptors may result in hyperactivation of this signaling cascade, which is recognized as a hallmark of cancer. Although higher activation of PI3K pathway is common in many types of cancer, it has been therapeutically targeted for the first time in chronic lymphocytic leukemia (CLL), demonstrating its significance in B-cell receptor (BCR) signaling and malignant B-cell expansion. The biological activity of the PI3K pathway is not only limited to cancer cells but is also crucial for many components of the tumor microenvironment, as PI3K signaling regulates cytokine responses, and ensures the development and function of immune cells. Therefore, the success or failure of the PI3K inhibition is strongly related to microenvironmental stimuli. In this review, we outline the impacts of PI3K inhibition on the tumor microenvironment with a specific focus on CLL. Acknowledging the effects of PI3K inhibitor-based therapies on the tumor microenvironment in CLL can serve as a rationale for improved drug development, explain treatment-associated adverse events, and suggest novel combinatory treatment strategies in CLL.

Crizotinib-resistant MET mutations in gastric cancer patients are sensitive to type II tyrosine kinase inhibitors.

Aim: Crizotinib has been used to counter MET amplification in different human malignancies. However, transient responses were observed in some patients with rapid acquisition of resistant mutations in MET. Materials & methods: MET mutations stably expressed Ba/F3 cell lines were used for IC50 detection. Signaling pathway analysis was done using 293T cell line. Results: Four MET mutations conferred resistance to crizotinib with sustained activation of downstream signaling pathways of MET. On the other hand, the four MET mutations displayed different response to type II tyrosine kinase inhibitors with variable deterioration of the downstream signals. Conclusion: This study suggested that patients carrying MET V1092L, D1228G or Y1230H mutations could benefit from type II tyrosine kinase inhibitor treatment, but not patients with G1163R or D1228Y/N mutations.

A 3D parameter correction technique for damage assessment of structural reinforced concrete beams by acoustic emission

Abstract Deterioration of ultrasonic signals obtained from nonhomogeneous mediums due to dispersion and attenuation is a crucial problem affecting the validities of elastic-wave-based nondestructive testing methods. Concrete, which is the main construction material, is also an excessively heterogeneous material as it consists of cement, water, aggregate and other admixtures. Because Acoustic Emission (AE) is known to be an appropriate method for detecting active damages nondestructively in concrete structures, enhancement of this technique is important for more reliable inspections. This paper describes development of a 3D Parameter Correction Technique (3D-PCT) and first application of AE parameter correction in reinforced concrete (RC). The technique was applied to plain and CFRP-strengthened RC beam specimens. Accordingly, AE data obtained from three-point-bending tests were localized, their signals and also amplitude and energy parameters were corrected in 3D space and parameter analyzes were conducted. By applying 3D-PCT for RC; corrected results were obtained, some AE parameter relations were altered and activity type classification was improved. Moreover, accordance with mechanical observations was enhanced.

Stall-Warning Approach Based on Aeroacoustic Principle

In a fan/compressor, the pass of the blade is a periodic event and this periodicity deteriorates when rotating stall is gradually approached. The present work studies this periodicity of the pressure signal and explains when and why this periodicity deterioration happens from the perspective of the aeroacoustic principle. A theoretical analysis shows that the change of blade circulation has a close association with rotating stall and can be reflected on the periodicity deterioration of pressure signals sampled by a near-field dynamic pressure sensor located on the casing wall. A defined parameter , which can revalue this periodicity, has the potential to be a stall-warning criterion. Then, a stall-warning approach is developed in terms of this feature. The values of are calculated by the pressure signals of several blade pitches based on the current and the previous shaft periods. Statistical estimations are conducted on within statistical windows by calculating the probabilities of less than a threshold. The relevant experiments are carried out on a low-speed compressor, a transonic compressor, and a low-speed fan. The results show that the proposed approach has the capability of generating a stall-warning signal sufficiently in advance of the modal wave and spike in turbomachinery.

Ballistocardiogram artifact correction taking into account physiological signal preservation in simultaneous EEG-fMRI

The ballistocardiogram (BCG) artifact is currently one of the most challenging in the EEG acquired concurrently with fMRI, with correction invariably yielding residual artifacts and/or deterioration of the physiological signals of interest. In this paper, we propose a family of methods whereby the EEG is decomposed using Independent Component Analysis (ICA) and a novel approach for the selection of BCG-related independent components (ICs) is used (PROJection onto Independent Components, PROJIC). Three ICA-based strategies for BCG artifact correction are then explored: 1) BCG-related ICs are removed from the back-reconstruction of the EEG (PROJIC); and 2–3) BCG-related ICs are corrected for the artifact occurrences using an Optimal Basis Set (OBS) or Average Artifact Subtraction (AAS) framework, before back-projecting all ICs onto EEG space (PROJIC-OBS and PROJIC-AAS, respectively). A novel evaluation pipeline is also proposed to assess the methods performance, which takes into account not only artifact but also physiological signal removal, allowing for a flexible weighting of the importance given to physiological signal preservation. This evaluation is used for the group-level parameter optimization of each algorithm on simultaneous EEG-fMRI data acquired using two different setups at 3T and 7T. Comparison with state-of-the-art BCG correction methods showed that PROJIC-OBS and PROJIC-AAS outperformed the others when priority was given to artifact removal or physiological signal preservation, respectively, while both PROJIC-AAS and AAS were in general the best choices for intermediate trade-offs. The impact of the BCG correction on the quality of event-related potentials (ERPs) of interest was assessed in terms of the relative reduction of the standard error (SE) across trials: 26/66%, 32/62% and 18/61% were achieved by, respectively, PROJIC, PROJIC-OBS and PROJIC-AAS, for data collected at 3T/7T. Although more significant improvements were achieved at 7T, the results were qualitatively comparable for both setups, which indicate the wide applicability of the proposed methodologies and recommendations.

Research on high power inter-channel crosstalk attack in optical networks

While all-optical networks become more and more popular as the basis of the next generation Internet (NGI) infrastructure, such networks raise many critical security issues. High power inter-channel crosstalk attack is one of the security issues which have negative effect on information security in optical networks. Optical fiber in optical networks has some nonlinear characteristics, such as self phase modulation (SPM), cross phase modulation (XPM), four-wave mixing (FWM) and stimulated Raman scattering (SRS). They can be used to implement high power inter-channel crosstalk attack by malicious attackers. The mechanism of high power inter-channel crosstalk attack is analyzed. When an attack occurs, attack signal power and fiber nonlinear refractive index are the main factors which affect quality of legitimate signals. The effect of high power inter-channel crosstalk attack on quality of legitimate signals is investigated by building simulation system in VPI software. The results show that inter-channel crosstalk caused by high power attack signal leads to quality deterioration of legitimate signals propagated in the same fiber. The higher the power of attack signal is, the greater the fiber nonlinear refractive index is. The closer the channel spacing away from the attack signal is, the more seriously the legitimate signals are affected by attack. We also find that when attack position and power of attack signal are constant, attack signal cannot infinitely spread, while its attack ability shows a fading trend with the extension of propagation distance.

Smart Laser Interferometer with Electrically Tunable Lenses for Flow Velocity Measurements through Disturbing Interfaces

Interferometric velocity measurements are of great importance at flow investigations. However, the laser beams can be distorted at the interfaces between optical media of different refractive indices. Temporal fluctuations of these distortions will cause a deterioration of the laser interferometer signals. We have harnessed the power of programmable photonics devices to eliminate this signal deterioration. Non-invasive flow velocity measurements through a rapidly fluctuating media interface with large strokes of about 100 microns are presented. Our work represents a paradigm shift for interferometric velocity measurement techniques from using static to dynamic optical elements.

Coding Techniques for High-Speed Data Transmission Based on Spectrum Shaping

The performance of advanced VLSI systems is limited by the interconnection bandwidthinside/between chips rather than individual performance of transistors. The attenuation or deteriorationof signals, arises from physical phenomena in transmission lines, restricts the maximum frequencyat which the signal can transmit. This paper investigates coding techniques that can modifysignal spectrum suited to channel frequency response based on the concept of spectrum shaping ofsignals. We discuss three types of coding techniques for high-speed serial links to evaluate their performanceas well as the feasibility for realizing efficient data transmission.

Tailing of Chromatographic Peaks in GC-MS Caused by Interaction of Halogenated Solvents with the Ion Source

The injection of analytes into a gas chromatography-mass spectrometry (GC-MS) system using dichloromethane (DCM) as solvent led to gradual deterioration of chromatographic signals, with significant tailing and loss of sensitivity for C17+ hydrocarbons. The injector, gas chromatograph and transfer line were excluded as causes. Normal peak shape could only be restored by the insertion of a cleaned MS ion source. To elucidate potential surficial contaminants, the ion source was heated from 260 to 320°C, leading to the release of increasing concentrations of ferrous chloride [FeCl2(g)]. The ferrous chloride probably formed through the decomposition of DCM on metal surfaces in the ion source. We posit that the tailing was caused by the adsorption of analytes to sub-µm layers of FeCl2 at crystal defect sites in the metal, followed by the slow release of molecules back into the gas phase. There are at least two other cases in the literature in which tailing is specifically associated with the use of halogenated solvents. However, it is possible that the problem is relatively common, albeit rarely diagnosed and reported. The tailing of chromatographic peaks caused by the formation of ferrous chloride in the mass spectrometer can be diagnosed by scanning the MS background signal for the diagnostic isotopic pattern of FeCl2(+). The problem is easily solved by cleaning the MS ion source and avoiding halogenated solvents.

Multiple-Valued Pulse-Position Modulation Techniques for Efficient Data Transmission

This paper proposes multiple-valued pulse-position modulation (MVPPM) techniques toachieve efficient data transmission in VLSI systems. The MVPPM coding employs 2-dimensional informationrepresentation in both time and amplitude domain to increase data rates. This time-domaininformation processing uses timing resolution, and therefore fits well with advanced high-speed lowvoltageCMOS processes. An 8-valued MVPPM transceiver is designed and simulated using SPICE todemonstrate the capability of compensating for deterioration of signals caused by interconnections.

A 2nd-Order PWM Pre-Emphasis Technique and its Experimental FPGA Implementation

In this paper, a Pulse-Width Modulation (PWM) pre-emphasis technique is extended to a2nd-order version to equalize a higher-order transfer function of an interconnection inside/betweenVLSI chips. The PWM pre-emphasis method does not change the pulse amplitude as for conventionalFIR pre-emphasis, but instead exploits timing resolution. As a proof of concept, a 2nd-order timedomainpre-emphasis technique is designed and implemented using an FPGA to demonstrate thecapability of compensating for deterioration of signals caused by interconnections with higher-ordertransfer functions.

Effect of Oxidation on Surface-Enhanced Raman Scattering Activity of Silver Nanoparticles: A Quantitative Correlation

We quantitatively studied, using X-ray photoelectron spectroscopy (XPS), oxidation of substrate-immobilized silver nanoparticles (Ag NPs) in a wide range of conditions, including exposure to ambient air and controlled ozone environment under UV irradiation, and we correlated the degree of silver oxidation with surface-enhanced Raman scattering (SERS) enhancement factors (EFs). The SERS activity of pristine and oxidized Ag NPs was assessed by use of trans-1,2-bis(4-pyridyl)ethylene (BPE) and sodium thiocynate as model analytes at the excitation wavelength of 532 nm. Our study showed that the exposure of Ag NPs to parts per million (ppm) level concentrations of ozone led to the formation of Ag(2)O and orders of magnitude reduction in SERS EFs. Such an adverse effect was also notable upon exposure of Ag NPs under ambient conditions where ozone existed at parts per billion (ppb) level. The correlated XPS and SERS studies suggested that formation of just a submonolayer of Ag(2)O was sufficient to decrease markedly the SERS EF of Ag NPs. In addition, studies of changes in plasmon absorption bands pointed to the chemical enhancement as a major reason for deterioration of SERS signals when substrates were pre-exposed to ambient air, and to a combination of changes in chemical and electromagnetic enhancements in the case of substrate pre-exposure to elevated ozone concentrations. Finally, we also found UV irradiation and ozone had a synergistic effect on silver oxidation and thus a detrimental effect on SERS enhancement of Ag NPs and that such oxidation effects were analyte-dependent, as a result of inherent differences in chemical enhancements and molecular binding affinities for various analytes.

Sleep deprivation impairs precision of waggle dance signaling in honey bees

Sleep is essential for basic survival, and insufficient sleep leads to a variety of dysfunctions. In humans, one of the most profound consequences of sleep deprivation is imprecise or irrational communication, demonstrated by degradation in signaling as well as in receiving information. Communication in nonhuman animals may suffer analogous degradation of precision, perhaps with especially damaging consequences for social animals. However, society-specific consequences of sleep loss have rarely been explored, and no function of sleep has been ascribed to a truly social (eusocial) organism in the context of its society. Here we show that sleep-deprived honey bees (Apis mellifera) exhibit reduced precision when signaling direction information to food sources in their waggle dances. The deterioration of the honey bee's ability to communicate is expected to reduce the foraging efficiency of nestmates. This study demonstrates the impact of sleep deprivation on signaling in a eusocial animal. If the deterioration of signals made by sleep-deprived honey bees and humans is generalizable, then imprecise communication may be one detrimental effect of sleep loss shared by social organisms.

Reflective SOA-Based Bidirectional WDM-PON Sharing Optical Source for Up/Downlink Data and Broadcasting Transmission

We proposed and experimentally demonstrated the reflective semiconductor optical amplifier (RSOA)-based wavelength-division-multiplexed passive optical network (WDM-PON) scheme where not only up/downlink data services but also broadcasting service could be provided using a single optical source. In the proposed scheme, the digital signal and subcarrier multiplexing (SCM) signal for downstream were simultaneously modulated by a single distributed feedback laser diode and RSOA in optical network unit remodulated downstream source as an upstream. Without performance deterioration of digital signals both in up- and downstream, the proposed WDM-PON scheme can stably offer the SCM signal for broadcasting service. In the experiment, 1-Gb/s digital signals both for up- and downstream and 20-Mb/s SCM signal at 2.2 GHz for broadcasting were demonstrated in 10-km bidirectional link

A 80-gbit/s D-type flip-flop circuit using InP HEMT technology

80-Gbit/s operation of a static D-type flip-flop (D-FF) circuit was achieved using InP-based HEMT technology, which has a cut-off frequency of 245 GHz and a transconductance of 1500 mS/mm. The circuit was designed with differential operation based on source-coupled FET logic (SCFL). To overcome deterioration of the 80-GHz clock signals in a single-ended to differential signal converter in the input buffer, a rat-race circuit was used as a converter. Measurements showed that the circuit achieved a gain of over 2 dB higher than a conventional converter using a differential pair circuit, and power consumption was reduced from 380 to 260 mW. The power supply voltage was -5.7 V, and total power consumption was 1.2 W. Since there is no commercially available 80-Gbit/s-pulse pattern generator, we developed a selector module to measure the D-FF. These measurements showed that the D-FF successfully operated at 80 Gbit/s, which is almost twice the speed reported to date.