المؤلفون: Dan Keun Sung, Xinming Zhang, Hui Zhang

المصدر: IEEE Transactions on Mobile Computing. 22:1880-1893

مصطلحات موضوعية: Computer Networks and Communications, business.industry, Computer science, Retransmission, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Latency (audio), Data_CODINGANDINFORMATIONTHEORY, Interference (wave propagation), law.invention, Relay, law, Metric (mathematics), Redundancy (engineering), Overhead (computing), Electrical and Electronic Engineering, business, Software, Selection (genetic algorithm), Computer network

الوصف: In VANETs, it is important to support fast and reliable multi-hop broadcast for safety-related applications. The performance of multi-hop broadcast schemes is greatly affected by relay selection strategies. However, the relationship between the relay selection strategies and the expected broadcast performance has not been fully characterized yet. Furthermore, conventional broadcast schemes usually attempt to minimize the waiting time difference between adjacent relay candidates to reduce the waiting time overhead, which makes the relay selection process vulnerable to internal interference, occurring due to retransmissions from previous forwarders and transmissions from redundant relays. In this paper, we jointly take both of the relay selection and the internal interference mitigation into account and propose a fast, reliable, opportunistic multi-hop broadcast scheme, in which we utilize a novel metric called the expected broadcast speed in relay selection and propose a delayed retransmission mechanism to mitigate the adverse effect of retransmissions from previous forwarders and an expected redundancy probability based mechanism to mitigate the adverse effect of redundant relays. The performance evaluation results show that the proposed scheme yields the best broadcast performance among the four schemes in terms of the broadcast coverage ratio and the end-to-end delivery latency.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::3edf7e5ffe048be6beec26d962c48309Test
https://doi.org/10.1109/tmc.2021.3119015Test

المؤلفون: Bingyan Chen, Fengshou Gu, Weihua Zhang, Yao Cheng, Guiming Mei

المصدر: ISA Transactions. 127:395-414

مصطلحات موضوعية: Bearing (mechanical), Frequency band, Computer science, business.industry, Applied Mathematics, Spectrum (functional analysis), Pattern recognition, Fault (power engineering), Interference (wave propagation), Radio spectrum, Computer Science Applications, law.invention, Control and Systems Engineering, Feature (computer vision), law, Artificial intelligence, Electrical and Electronic Engineering, Envelope (radar), business, Instrumentation

الوصف: Identifying a spectral frequency band with abundant fault information from spectral coherence is essential for improved envelope spectrum-based bearing diagnosis. Both blind features and targeted features have been employed to distinguish informative spectral frequency band of spectral coherence. However, how to select appropriate feature to correctly discriminate the optimal frequency band of spectral coherence in different scenarios is problematic. In this study, a new targeted feature is presented to quantify the signal-to-noise ratio in narrow frequency bands of spectral coherence, and further a method based on the proposed feature is developed to distinguish an optimal spectral frequency band of spectral coherence for bearing diagnostics. The efficiency of the developed method, typical blind feature-based methods and typical targeted feature-based methods in identifying the defect-sensitive frequency band of spectral coherence and bearing fault diagnosis is validated and compared using simulated signals with different interference noises and bearing experimental signals. The advantages and limitations of typical blind and targeted feature-based methods in different scenarios are summarized to guide the application. The results demonstrate that the developed targeted feature can efficiently evaluate bearing failure information in the cyclic frequency domain, and the presented approach can accurately discriminate the failure-related spectral frequency band of spectral coherence and detect different bearing faults compared with the methods based on the state-of-the-art features.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::39b782f865b9dd60bb13d6cfb4c792b6Test
https://doi.org/10.1016/j.isatra.2021.08.025Test

المؤلفون: Deepak Saluja, Rohit Singh, Suman Kumar

المصدر: IEEE Transactions on Intelligent Transportation Systems. 23:10418-10426

مصطلحات موضوعية: Computer science, Mechanical Engineering, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Real-time computing, Interference (wave propagation), Computer Science Applications, law.invention, Spread spectrum, Transmission (telecommunications), law, Automotive Engineering, Range (statistics), Graph (abstract data type), Resource allocation, Waveform, Radar

الوصف: Autonomous Vehicles (AVs) rely on a set of radar sensors operated on frequency modulated waveforms. Due to the large bandwidth requirement of frequency modulated radars, only a limited number of proximate vehicles can be allowed for a concurrent transmission within the available spectrum. However, with the explosive growth of AVs, the available spectrum may soon reach its capacity. As a results, the coexistence of multiple AVs working on same resource, may lead to the problem of Radar-to-Radar (R2R) interference, also known as radar blindness. In this paper, we propose the notion of coded waveforms to minimize the R2R interference among the vehicles operating on the same resource. Specifically, the spread spectrum codes have been used as another degree of freedom (i.e., along with time-frequency resources) to spread the inter-vehicular radar interference over the wider spectrum, which enable to orthogonalize more number of AVs over the available range of spectrum. In addition, we have formulated a Spread Spectrum-based Radar Transmission Scheme (SS-RTS), and described the transmission and reception through SS-RTS. Also, the SS-RTS has been compared with the existing Graph-based Resource Allocation (GRA) scheme. Further, simulation results verified that SS-RTS significantly reduces the inter-vehicular R2R interference and outperforms GRA in terms of blind probability.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::80caf185bdb25aa7ea75fd8284afef97Test
https://doi.org/10.1109/tits.2021.3094199Test

المؤلفون: Hong Wen, Zhumu Fu, Dun Cao, Peng Li, Baofeng Ji, Fazhan Tao, Han Ying, Yanan Wang

المصدر: IEEE Transactions on Intelligent Transportation Systems. 23:9712-9725

مصطلحات موضوعية: Correctness, Computer science, Mechanical Engineering, Node (networking), ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Interference (wave propagation), Telecommunications network, Computer Science Applications, law.invention, Transmission (telecommunications), Relay, law, Automotive Engineering, Algorithm, 5G, Decoding methods

الوصف: The Internet of Vehicles (IoV) has always attracted attention as the emerging communication network with the most development potential in the 5G era. However, the performance of IoV under 5G ultra-dense networks is an open issue, especially in practice the outage probability and ergodic capacity of the relay cooperative IoV network under aggregate interference are still unclear. Therefore, an opportunistic Decoding and Forwarding (DF) relay cooperative transmission algorithm was proposed in this paper when the destination node of IoV has aggregated interference. In addition, based on mathematical theoretical knowledge such as numerical analysis, the closed expressions of the outage probability and ergodic capacity of the IoV system under aggregated interference was derived. Finally, simulation experiments verify the effectiveness of the proposed scheme and the correctness of the theoretical analysis, which improves the transmission rate of the system.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::b524087cb9d5bc041b1914a416696f43Test
https://doi.org/10.1109/tits.2021.3106545Test

المؤلفون: Yuh-Ren Tsai, Yi-Ming Chiu

المصدر: IEEE Systems Journal. 16:3400-3409

مصطلحات موضوعية: Beamforming, Computer Networks and Communications, Computer science, Phased array, Radio Link Protocol, MIMO, Transmitter, Interference (wave propagation), Computer Science Applications, law.invention, Control and Systems Engineering, law, Distortion, Electronic engineering, Electrical and Electronic Engineering, Antenna (radio), Information Systems

الوصف: Multiple-input–multiple-output (MIMO) is a key technology used to meet the requirements of 5G systems. In millimeter-wave (mmWave) bands, directional beamforming is applied at both the transmitter and the receiver to establish an efficient radio link. The mmWave bands specified in 5G specifications range from 24.25 to 40.0 GHz. Accordingly, different countries may allocate different bands to support 5G services because of the availability of the spectrum and the countries’ radio management policies. For international roaming, user equipment (UE) must support multiband operations based on a fixed antenna hardware structure that is designed to target a specific operating band. Hence, the frequency discrepancy that results from using different operating bands causes distortion in the achieved beamforming pattern. In this article, we investigate the impact of frequency discrepancy on beamforming performance in mmWave phased array antenna systems at the UE side, considering the resultant beam pattern and interference. In this effort, we studied three major side effects—deviation of the beamforming direction, change in the effective array length, and change in the normalized interelement spacing. The numerical results indicate that a large frequency discrepancy causes severe distortion in the resultant beamforming pattern and introduces more interference into the system.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::a66e1f2bbf5d17319880664ee48552c6Test
https://doi.org/10.1109/jsyst.2021.3088588Test

المؤلفون: Isami Nitta, Yosuke Tsukiyama

المصدر: Precision Engineering. 75:248-262

مصطلحات موضوعية: Materials science, Microscope, business.industry, General Engineering, Linear stage, Interference (wave propagation), Laser, law.invention, Vibration, Interferometry, Optics, law, Distortion, Wafer, business

الوصف: Here, we report measurements made with an external vibration-insensitive single-shot interferometer, which is applicable for on-machine measurement. Previously, we developed a simple single-shot interferometry method in which the optical intensities of interference fringes appear not as sinusoidal distributions but have a sawtooth-like distribution, and the peak distortion direction depicts the slope of the measured surfaces. These properties allow use of this method in vibration-insensitive interferometry. In this study, we have experimentally confirmed this concept through measurement of a quarter of a Si wafer specimen 50 mm in diameter. The vibration source was a motorized linear stage the surface of which fluctuated between ±400 nm in height. The obtained surface profiles of the Si wafer were consistent with measurements made with a commercial interferometer within 30 nm.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::a5c66d4413c540ac2e2044e6f6baa13eTest
https://doi.org/10.1016/j.precisioneng.2021.10.012Test

المؤلفون: Jiannan Tu, W. R. Johnston, Bodo W. Reinisch, Ivan Galkin, Paul Song

المصدر: IEEE Transactions on Antennas and Propagation. 70:2915-2927

مصطلحات موضوعية: Physics, Fresnel zone, business.industry, Plasma, Interference (wave propagation), law.invention, Magnetic field, Optics, law, Group velocity, Dipole antenna, Electrical and Electronic Engineering, Antenna (radio), business, Radiation resistance, Computer Science::Information Theory

الوصف: We treat whistler mode radiation from a dipole antenna in a cold magnetized plasma based on the Fresnel zone construction theory. Radiated waves from the antenna with different propagation directions interfere in space. Regions of enhanced waves are formed when the interference is predominantly constructive at the observing point. The coherently enhanced wave propagates at the group velocity. If the antenna is perpendicular to the background magnetic field, the regions of strong waves form two back-to-back Fresnel zones that are parabolic-shaped cones along the background magnetic field from the antenna. The power within each cone drops with distance at a rate of 1/r much more slowly than the 1/r2 thinning of a spherical wave as in vacuum. The total radiation can be approximately derived by the total energy flux integrated over the Fresnel zone. The derived radiation resistance is much greater than that in vacuum. It is proportional to frequency as 1/f2 and proportional to the antenna length as d2. To radiate more power a longer antenna is preferred, a result that is opposite to some previous theoretical studies.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::cf41cc24309d48c19f6b38d5ef2e95d3Test
https://doi.org/10.1109/tap.2021.3121144Test

المؤلفون: Yao Guo, Song Liu, David C. Jeong, Yuyu Jia, Chengxi Zhong

المصدر: IEEE Robotics and Automation Letters. 7:666-673

مصطلحات موضوعية: Forward kinematics, Control and Optimization, Inverse kinematics, Computer science, Phased array, Mechanical Engineering, Acoustics, Biomedical Engineering, Holography, Acoustic wave, Sound power, Interference (wave propagation), Computer Science Applications, law.invention, Computer Science::Robotics, Human-Computer Interaction, Transducer, Computer Science::Sound, Artificial Intelligence, Control and Systems Engineering, law, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, Computer Vision and Pattern Recognition

الوصف: Holographic acoustic field has shown great potential for non-contact robotic manipulations of millimeter or sub-millimeter size objects to effectively deliver acoustic power. The latest technology for generating dynamic holographic acoustic field is through phased transducer array, where relative phases of emitted acoustic waves from transducers are independently controlled to modulate the acoustic interference field. While the forward kinematics of a phased array based robotic manipulation system is simple and straightforward, the inverse kinematics (i.e., the mapping from a given holographic acoustic field to array phases for control purpose), however, is mathematically non-linear and unsolvable, presenting challenges in developing wider applications of holographic acoustic field for robotic manipulation. Considering, thus far, there are still no effective solutions reported, the authors put intensive efforts to solve this problem using a machine learning approach, which we refer to as AcousNet. Experimental results demonstrate the effectiveness of the proposed method for dynamic holographic acoustic field generation from phased transducer array.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::766f29d0fc8a7f6685da80a04a265052Test
https://doi.org/10.1109/lra.2021.3130368Test

المؤلفون: Deepak Saluja, Rohit Singh, Suman Kumar

المصدر: IEEE Transactions on Intelligent Vehicles. 7:83-92

مصطلحات موضوعية: Control and Optimization, Computer science, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Real-time computing, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Communications system, Interference (wave propagation), law.invention, Transmission (telecommunications), Artificial Intelligence, law, Automotive radar, Automotive Engineering, Range (statistics), Radar, Joint (audio engineering), Intelligent transportation system

الوصف: Automotive radar and vehicular communication are the two primary means of establishing an intelligent transportation system. However, both the systems are susceptible to interference. The inter-vehicular interference significantly affects the radar and communication performance, especially in the dense traffic scenarios. In this work, we have shown that lowering down radar range in dense traffic scenario provides twofold advantages; (a) it reduces radar-to-radar interference and, (b) it provides resources to support the vehicular communication. We propose a joint Radar-Communication (R-Comm) algorithm which enables connected vehicles to use a fraction of radar resources for vehicular communication based on the traffic density. Also, two different schemes have been proposed for R-Comm transmission in the sparse and dense traffic scenarios. Further, through simulation results, it is shown that R-Comm benefits both the radar and communication systems.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::6f07880c947cab9b36aba4f02a47e37aTest
https://doi.org/10.1109/tiv.2021.3074389Test

المؤلفون: Xuefeng Ni, Hongli Liu, Ziji Ma, Bo Shi, Jianwei Liu

المصدر: IEEE Transactions on Industrial Informatics. 18:1694-1705

مصطلحات موضوعية: Artificial neural network, business.industry, Computer science, Machine vision, Deep learning, Pattern recognition, Interference (wave propagation), Computer Science Applications, law.invention, Control and Systems Engineering, law, Key (cryptography), Point estimation, Artificial intelligence, Hourglass, Electrical and Electronic Engineering, business, Information Systems, Block (data storage)

الوصف: Rail surface defect inspection based on machine vision faces challenges against the complex background with interference and severe data imbalance. To meet these challenges, we regard defect detection as a key-point estimation problem and present the attention neural network for rail surface defect detection via CASIoU-guided center-point estimation (CCEANN). CCEANN contains two crucial components. One is the stacked attention Hourglass backbone via cross-stage fusion of multi-scale features (CSFA-Hourglass), in which the convolutional block attention module with variable receptive fields (VRF-CBAM) is introduced, and a two-stage Hourglass structure balancing the network depth and feature fusion plays a key role. Furthermore, the CASIoU-guided center-point estimation head module (CASIoU-CEHM) integrating the delicate coordinate compensation mechanism regresses detection boxes flexibly to adapt to defects' large-scale variation, in which the proposed CASIoU loss, a loss regressing the consistency of Intersection-over-Union (IoU), central-point distance, area ratio, and scale ratio between the targeted defect and the predicted defect, achieves higher regression accuracy than state-of-the-art IoU-based losses. The experiments demonstrate that CCEANN outperforms competitive deep learning-based methods in four surface defect datasets.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::c863fca8b0dcc62a46fc7c2110ccaf90Test
https://doi.org/10.1109/tii.2021.3085848Test