Hardware impairments(HI)are always present in low-cost wireless *** paper investigates the outage behaviors of intelligent reflecting surface(IRS)assisted non-orthogonal multiple access(NOMA)networks by taking into ac...
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Hardware impairments(HI)are always present in low-cost wireless *** paper investigates the outage behaviors of intelligent reflecting surface(IRS)assisted non-orthogonal multiple access(NOMA)networks by taking into account the impact of ***,we derive the approximate and asymptotic expressions of the outage probability for the IRS-NOMA-HI *** on the asymptotic results,the diversity orders under perfect self-interference cancellation and imperfect self-interference cancellation scenarios are obtained to evaluate the performance of the considered *** addition,the system throughput of IRS-NOMA-HI is discussed in delay-limited *** obtained results are provided to verify the accuracy of the theoretical analyses and reveal that:1)The outage performance and system throughput for IRS-NOMA-HI outperforms that of the IRS-assisted orthogonal multiple access-HI(IRS-OMA-HI)networks;2)The number of IRS elements,the pass loss factors,the Rician factors,and the value of HI are pivotal to enhancing the performance of IRS-NOMAHI networks;and 3)It is recommended that effective methods of reducing HI should be used to ensure system performance,in addition to self-interference cancellation techniques.
The use of terahertz time-domain spectroscopy(THz-TDS)for the nondestructive testing and evaluation(NDT&E)of materials and structural systems has attracted significant attention over the past two decades due to it...
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The use of terahertz time-domain spectroscopy(THz-TDS)for the nondestructive testing and evaluation(NDT&E)of materials and structural systems has attracted significant attention over the past two decades due to its superior spatial resolution and capabilities of detecting and characterizing defects and structural damage in non-conducting *** this study,the THz-TDS system is used to detect,localize and evaluate hidden multi-delamination defects(i.e.,a three-level multi-delamination system)in multilayered GFRP composite *** obtain accurate results,a wavelet shrinkage de-noising algorithm is used to remove the noise from the measured time-of-flight(TOF)*** thickness and location of each delamination defect in the z-direction(i.e.,through-the-thickness direction)are calculated from the de-noised TOF signals considering the interaction between the pulsed THz waves and the different interfaces in the GFRP composite laminates.A comparison between the actual and the measured thickness values of the delamination defects before and after the wavelet shrinkage denoising process indicates that the latter provides better results with less than 3.712%relative error,while the relative error of the non-de-noised signals reaches 16.388%.Also,the power and absorbance levels of the THz waves at every interface with different refractive indices in the GFRP composite laminates are evaluated based on analytical and experimental *** present study provides an adequate theoretical analysis that could help NDT&E specialists to estimate the maximum thickness of GFRP composite materials and/or structures with different interfaces that can be evaluated by the ***,the accuracy of the obtained results highlights the capabilities of the THz-TDS for the NDT&E of multilayered GFRP composite laminates.
Metamaterials(MMs)have become increasingly prominent in terahertz flexible ***,bending deformation often alters the structure of the unit,which affects the response performance and stability of ***,a metal-aperture me...
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Metamaterials(MMs)have become increasingly prominent in terahertz flexible ***,bending deformation often alters the structure of the unit,which affects the response performance and stability of ***,a metal-aperture metamaterial(MA-MM)utilizing the strong coupling effect induced by two resonance modes is innovatively proposed to address the mentioned ***,it is found that the coupling state between multiple resonance modes remains consistent at different bending *** these circumstances,the generated Rabi splitting peak presents stable response performance even under low resonance intensity caused by excessive *** experimental results demonstrate that despite the amplitude of two resonant peaks decreasing significantly by 87.6%,the Q-factor of the Rabi splitting only reduced by 14.8%.Furthermore,armed with the response mode of the Rabi splitting being unaffected by plasma excitation range,the designed MA-MMs are able to maintain constant Q-factors and frequencies on curved surfaces of varying *** findings exhibit the characteristics of electromagnetic response for multi-mode resonance-coupled MAMMs on different curved surfaces,presenting a novel design approach for terahertz flexible functional devices.
In terms of fault diagnosis and prediction, new equipment mainly has the characteristics of small data samples and increasing sample size. In the rulemaking process, there are problems such as incomplete data, insuffi...
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As a nondestructive testing technique,terahertz time-domain spectroscopy technology is commonly used to measure the thickness of ceramic coat in thermal barrier coatings(TBCs).However,the invisibility of ceramic/therm...
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As a nondestructive testing technique,terahertz time-domain spectroscopy technology is commonly used to measure the thickness of ceramic coat in thermal barrier coatings(TBCs).However,the invisibility of ceramic/thermally grown oxide(TGO)reflective wave leads to the measurement failure of natural growth TGO whose thickness is below 10μm in *** detect and monitor TGO in the emergence stage,a time of flight(TOF)improved TGO thickness measurement method is proposed.A simulative investigation on propagation characteristics of terahertz shows the linear relationship between TGO thickness and phase shift of feature *** accurate TOF increment could be acquired from wavelet soft threshold and cross-correlation function with negative effect reduction of environmental noise and system ***,the TGO thickness could be obtained efficiently from the TOF increment of the monitor area with different heating *** averaged error of 1.61μm in experimental results demonstrates the highly accurate and robust measurement of the proposed method,making it attractive for condition monitoring and life prediction of TBCs.
In terms of fault diagnosis and prediction, new equipment mainly has the characteristics of small data samples and increasing sample size. In the rulemaking process, there are problems such as incomplete data, insuffi...
In terms of fault diagnosis and prediction, new equipment mainly has the characteristics of small data samples and increasing sample size. In the rulemaking process, there are problems such as incomplete data, insufficient rules support, low accuracy data and information completeness, the current method is difficult to automatically correct forward rules based on continuously accumulated data. There is a lack of basic models and algorithms for rule correction, This method establishes an initial rule library after modeling system faults based on knowledge and data fusion. When a system fault occurs, it will exhibit various abnormal phenomena, and the collection of different types of abnormal phenomena (i.e. fault phenomena) corresponds to typical faults.
Sensing is the fundamental technique for sensor data acquisition in monitoring the operation condition of the machinery,structures,and manufacturing *** this paper,we briefly discuss the general idea and advances of v...
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Sensing is the fundamental technique for sensor data acquisition in monitoring the operation condition of the machinery,structures,and manufacturing *** this paper,we briefly discuss the general idea and advances of various new sensing technologies,including multiphysics sensing,smart materials and metamaterials sensing,microwave sensing,fiber optic sensors,and terahertz sensing,for measuring vibration,deformation,strain,acoustics,temperature,spectroscopic,*** on the observations from the state of the art,we provide comprehensive discussions on the possible opportunities and challenges of these new sensing technologies so as to steer future development.
ADAPTIVE control is a proven method for learning feedback controllers for systems with unknown dynamic models,exogenous disturbances,nonzero setpoints,and unmodeled *** control has been applied for years in process co...
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ADAPTIVE control is a proven method for learning feedback controllers for systems with unknown dynamic models,exogenous disturbances,nonzero setpoints,and unmodeled *** control has been applied for years in process control,industry,aerospace systems。
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