- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Remote Sensing-Based Proxies for Urban Disaster Risk Management and Resilience: A Review
摘要： Rapid increase in population and growing concentration of capital in urban areas has escalated both the severity and longer-term impact of natural disasters. As a result, Disaster Risk Management (DRM) and reduction have been gaining increasing importance for urban areas. Remote sensing plays a key role in providing information for urban DRM analysis due to its agile data acquisition, synoptic perspective, growing range of data types, and instrument sophistication, as well as low cost. As a consequence numerous methods have been developed to extract information for various phases of DRM analysis. However, given the diverse information needs, only few of the parameters of interest are extracted directly, while the majority have to be elicited indirectly using proxies. This paper provides a comprehensive review of the proxies developed for two risk elements typically associated with pre-disaster situations (vulnerability and resilience), and two post-disaster elements (damage and recovery), while focusing on urban DRM. The proxies were reviewed in the context of four main environments and their corresponding sub-categories: built-up (buildings, transport, and others), economic (macro, regional and urban economics, and logistics), social (services and infrastructures, and socio-economic status), and natural. All environments and the corresponding proxies are discussed and analyzed in terms of their reliability and sufficiency in comprehensively addressing the selected DRM assessments. We highlight strength and identify gaps and limitations in current proxies, including inconsistencies in terminology for indirect measurements. We present a systematic overview for each group of the reviewed proxies that could simplify cross-fertilization across different DRM domains and may assist the further development of methods. While systemizing examples from the wider remote sensing domain and insights from social and economic sciences, we suggest a direction for developing new proxies, also potentially suitable for capturing functional recovery.
关键词： damage,urban DRM,vulnerability,proxy,indirect measurement,social,resilience,remote sensing,recovery,economic
更新于2025-09-09 09:28:46
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[IEEE NAECON 2018 - IEEE National Aerospace and Electronics Conference - Dayton, OH, USA (2018.7.23-2018.7.26)] NAECON 2018 - IEEE National Aerospace and Electronics Conference - Improved Image Processing in Quaternary Logic
摘要： Quaternary logic is a four-valued logic. In quaternary logic, the gray level of the image is divided into more levels. This helps to increase the resolution and to decrease the quantization error of the image than that in binary logic representation. This improvement improvement of target detection, medical imaging, weather monitoring, environmental change detection, planetary and astrophysical imaging and other fields. There are different image inversions in quaternary logic, which are shown in this work. Besides this, successful image transmission through the bandwidth limited channel is also revealed in this work. The comparative study of Peak-Signal-to-Noise Ratio (PSNR) of the received image in this work shows better performance compared to other similar works.
关键词： Image compression,Quaternary,Image processing,Image resolution,Image inversion,Image recovery,Image transmission
更新于2025-09-09 09:28:46
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ISAR IMAGING BASED ON ITERATIVE REWEIGHTED LP BLOCK SPARSE RECONSTRUCTION ALGORITHM
摘要： Sparse signal recovery algorithms can be used to improve radar imaging quality by using the sparse property of strong scatterers. Traditional sparse inverse synthetic aperture radar (ISAR) imaging algorithms mainly consider the recovery of sparse scatterers. However, the scatterers of an ISAR target usually exhibit block or group sparse structure. By utilizing the inherent block sparse structure of ISAR target images, an iterative reweighted lp (0 < p ≤ 1) block sparse signal recovery algorithm is proposed to enhance imaging quality in this paper. Firstly, an ISAR imaging signal model is established with the aid of sparse basis, and the imaging is mathematically converted into block reweighted cost function optimization problem. Then, an iterative algorithm is used to solve the reweighted function minimization problem. In each iteration, the weights are updated based on the closed form solution of the previous iteration. The proposed method is e?ective to exploit the underlying block sparse structures which does not need the prior knowledge of the number of the blocks. Real data ISAR imaging results are provided to verify that the proposed algorithm in this paper can achieve better images than the images obtained by several popular sparse signal recovery algorithms.
关键词： iterative reweighted lp,block sparse,signal recovery,ISAR imaging
更新于2025-09-09 09:28:46
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Low-complexity Blind Carrier Phase Recovery for C-mQAM Coherent Systems
摘要： A novel carrier phase recovery algorithm is proposed for coherent optical systems with circular multilevel quadrature amplitude modulation (C-mQAM). After amplitude segmentation and phase rotation, the particular distribution of the constellation points in a C-mQAM signal is exploited to construct a special cost function to provide a rough estimate of phase noise. The cost function can be replaced with a simple cosine function, and only two or three test phases are required for the calculation of its parameters. The performances of different cost functions are compared and simulation results show that the cost function can be chosen with the high phase noise tolerance and low computational complexity. Maximum-likelihood (ML) phase noise estimation algorithm is combined with the proposed algorithm to mitigate residual phase noise. Compared to the single-stage blind phase search (BPS) and n-phase shift keying (n-PSK) partitioning algorithms, the numerical results demonstrate that the proposed two-stage algorithm shares similar phase noise tolerance and offers a lower computational complexity for a 28GBaud back-to-back coherent optical QAM transmission system.
关键词： circular multilevel quadrature amplitude modulation (C-mQAM),coherent optical communication,blind phase recovery (BPR),computational complexity (CC)
更新于2025-09-09 09:28:46
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Optical Interferometry || Digital Processing Techniques for Fringe Analysis
摘要： Digital image processing techniques are needed in order to recover the object information encoded in fringe patterns generated in a determined interferometric setup. Main fringe analysis techniques are reviewed in order to give the reader the most fundamental insights for the interpretation of interferograms. Phase shifted, open fringe, lateral shear and other types of interferograms make use of specific procedures to correctly retrieving the searched phase. Here, algorithms are described and tested in numerical simulations and real data.
关键词： fringe analysis,phase unwrapping,phase recovery
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Deploying enclosed trough for thermal EOR at commercial scale
摘要： Solar energy, in the form of enclosed trough direct steam generation, is now being deployed at scale to supply a portion of the energy demand for thermal enhanced oil recovery in Amal, Oman. Construction of the 1,021 MW Miraah project is well along and progress in cost reduction and labor productivity are evaluated. Results from the successful Manufacturing Verification Test and the Miraah Solar Steam Generator Project are presented and discussed. The Miraah data shows substantial reductions in material usage as a result of improved designs, increases in construction speed, and reductions in labor per unit of construction with deployment of enhanced tooling.
关键词： labor productivity,enclosed trough,thermal enhanced oil recovery,cost reduction,solar energy,direct steam generation
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Miramar Beach, FL (2018.8.22-2018.8.24)] 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Electrical and Structural Characterization of Si Implanted Homoepitaxially Grown AlN
摘要： AlN is an attractive material for UV optoelectronics and high-power device applications; however, obtaining high n-type conductivity is still a challenge. Ion implantation may provide an avenue to realize electrical conductivities suitable for device operation. A novel annealing procedure to recover lattice damage is presented.
关键词： damage and recovery,annealing,ion implantation
更新于2025-09-04 15:30:14
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Molecular Modeling of CO2 and n-Octane in Solubility Process and α-Quartz Nanoslit
摘要： After primary and secondary oil recovery, CO2-enhanced oil recovery (EOR) has become one of the most mentioned technologies in tertiary oil recovery. Since the oil is confined in an unconventional reservoir, the interfacial properties of CO2 and oil are different from in conventional reservoirs, and play a key role in CO2 EOR. In this study, molecular dynamics simulations are performed to investigate the interfacial properties, such as interfacial tension, minimum miscibility pressure (MMP), and CO2 solubility. The vanishing interfacial tension method is used to get the MMP (~10.8 MPa at 343.15 K) which is in agreement with the reported experimental data, quantitatively. Meanwhile, the diffusion coefficients of CO2 and n-octane under different pressures are calculated to show that the diffusion is mainly improved at the interface. Furthermore, the displacement efficiency and molecular orientation in α-quartz nanoslit under different CO2 injection ratios have been evaluated. After CO2 injection, the adsorbed n-octane molecules are found to be displaced from surface by the injected CO2 and, then, the orientation of n-octane becomes more random, which indicates that and CO2 can enhance the oil recovery and weaken the interaction between n-octane and α-quartz surface. The injection ratio of CO2 to n-octane is around 3:1, which could achieve the optimal displacement efficiency.
关键词： molecular dynamics simulation,CO2-enhanced oil recovery,minimum miscibility pressure,α-quartz pore,n-octane
更新于2025-09-04 15:30:14
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[IEEE 2016 IEEE International Symposium on Circuits and Systems (ISCAS) - Montréal, QC, Canada (2016.5.22-2016.5.25)] 2016 IEEE International Symposium on Circuits and Systems (ISCAS) - A 800-Mb/s 0.89-pJ/b reference-less optical receiver with pulse-position-modulation scheme
摘要： A 800-Mb/s optical receiver based on pulse-position-modulation (PPM) scheme is presented. The proposed PPM receiver can recover the clock without any help of a reference clock or a forwarded clock. As a result, the number of wire and pin count is minimized. Moreover, the proposed receiver employs optical front-end circuits for fiber-optic communications which is optimized for low-power operation. The clock and data recovery (CDR) circuit is implemented with only a PLL and a sampling flip-flop to minimize the power consumption of the proposed receiver. A prototype chip is fabricated in 65-nm CMOS technology and dissipates 711 μW at 800-Mb/s data rate, achieving the power efficiency of 0.89 pJ/b. The measured jitter tracking bandwidth of the proposed receiver is about 10 MHz and the receiver sensitivity is measured to be -9.7 dBm for the BER of 10-12.
关键词： low-power,pulse position modulation (PPM),Clock and data recovery (CDR),optical front-end,reference-less receiver
更新于2025-09-04 15:30:14
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UAV Scale Coaxial Rotor Aerodynamic Interactions Investigation Through High-Speed PIV and Performance Measurements
摘要： Coaxial rotor UAVs are compact compared to single rotor UAVs of comparable capacity. At the low Reynolds Numbers (Re) where they operate, the simplifying assumptions from high Re rotor aerodynamics are not valid. The low Re coaxial rotor ?ow?eld is studied including aerodynamic interactions and their effect on performance. The evolution of the wake is captured using high speed Stereo Particle Image Velocimetry (SPIV). Improvement of upper rotor performance due to viscous swirl recovery from the lower rotor is discovered and then veri?ed by analyzing PIV data. Interesting vortex - vortex sheet interactions are observed under the coaxial rotor affecting wake structure spatially and temporally. A qualitative model explaining the observed wake interaction phenomena is presented. Comparison with the performance of high Re rotors shows higher pro?le and induced drag at low Re for the same thrust coef?cient.
关键词： Viscous swirl recovery,High-speed PIV,Aerodynamic interactions,Performance measurements,Low Reynolds number,Coaxial rotor,Vortex-vortex sheet interactions,UAV
更新于2025-09-04 15:30:14