- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Topology Design for Geosynchronous Spaceborne–Airborne Multistatic SAR
摘要： Geosynchronous (GEO) spaceborne–airborne multistatic synthetic aperture radar (GEO MulSAR) is more flexible and accessible in remote sensing applications because of the high-altitude illuminator and the separation of the receivers and transmitter. In addition, the information obtained by the multiple airborne receivers can be fused to enhance the spatial resolution. However, the fused spatial resolution severely depends on the applied multistatic topology. To achieve the optimal fused spatial resolution by properly adjusting the imaging topology, a topology design method is proposed in this letter. First, the spatial resolution model of GEO MulSAR is given, and the dependence of the spatial resolution on the multistatic topology is analyzed in detail. Then, a topology design method is proposed to obtain the best multistatic topology that simultaneously optimizes the resolution cell area and resolution disequilibrium factor. Finally, the simulation results validate the effectiveness of the proposed method, and some insights into designing the multistatic topology are given.
关键词： resolution enhancement,topology design,Geosynchronous (GEO) spaceborne–airborne synthetic aperture radar (SAR),multistatic SAR
更新于2025-09-09 09:28:46
-
Incoherent Synthesis of Sparse Arrays for Frequency-Invariant Beamforming
摘要： Frequency-invariant beamformers are used to prevent signal waveform distortions in real world applications like audio, underwater acoustics, and radar. Most of existing methods assume uniform arrays, and only few consider sparse designs, which may lead to higher performance in terms of robustness and directivity factor. We propose an incoherent approach that first determines for each frequency bin a sparse set of sensors positions. Subsequently, by using tools of dimensionality reduction and clustering, these selections are merged together yielding the optimal sensors on a sparse array layout. We present design examples of sparse linear and planar superdirective array designs. We show that the proposed incoherent sparse design obtains superior performance in terms of white noise gain, directivity factor, and computational load compared to a uniform array design and compared to a coherent sparse approach, where the sensors’ locations and the beamformer coefficients are optimized simultaneously for all frequencies.
关键词： Frequency-invariant beamformer,superdirective beamformers,differential microphone arrays,sparse design
更新于2025-09-09 09:28:46
-
Rationalizing Perovskites Data for Machine Learning and Materials Design
摘要： Machine learning has been recently used for novel perovskite designs, owing to the availability of large amount of perovskite formability data. Trustworthy results should be based on the valid and reliable data that can reveal the nature of materials as much as possible. In this study, a procedure has been developed to identify the formability of perovskites for all the compounds with the stoichiometry of ABX3 and (A′A′′)(B′B′′)X6, that exist in experiments and are stored in the database of Materials Projects. Our results have enriched data of perovskite formability in a large extent and corrected the possible errors of previous data in ABO3 compounds. Furthermore, machine learning with multiple models approach have identified the A2B′B′′O6 compounds that have suspicious formability results in current experimental data. Therefore, further experimental validation experiments are called for. This work paves a way for cleaning perovskite formability data for reliable machine learning work in future.
关键词： Perovskites,Energy Conversion and Storage,Machine Learning,Plasmonics and Optoelectronics,Materials Design
更新于2025-09-09 09:28:46
-
Same but different - Scale up and numbering up in electrobiotechnology and photobiotechnology
摘要： Facing energy problems, there is a strong demand for new technologies dealing with the replacement of fossil fuels. The emerging fields of biotechnology, photobiotechnology and electrobiotechnology, offer solutions for the production of fuels, energy or chemicals using renewable energy sources (light or electrical current e.g. produced by wind or solar power) or organic (waste) substrates. From an engineering point of view both technologies have analogies and some similar challenges, since both light and electron transfer are primarily surface-dependent. In contrast to that, bioproduction processes are typically volume-dependent. To allow large scale and industrially relevant applications of photobiotechnology and electrobiotechnology, this opinion first gives an overview over the current scales reached in these areas. We then try to point out the challenges and possible methods for the scale up or numbering up of the reactors used. It is shown that the field of photobiotechnology is by now much more advanced than electrobiotechnology and has achieved industrial applications in some cases. We argue that transferring knowledge from photobiotechnology to electrobiotechnology can speed up the development of the emerging field of electrobiotechnology. We believe that a combination of scale up and numbering up, as it has been shown for several photobiotechnological reactors, may well lead to industrially relevant scales in electrobiotechnological processes allowing an industrial application of the technology in near future.
关键词： numbering up,photobiotechnology,reactor design,scale up,Electrobiotechnology
更新于2025-09-09 09:28:46
-
Radiation-induced loss of silica optical fibres with fluorine-doped cladding
摘要： The effect of gamma-irradiation of the fluorine-doped silica depressed cladding graded-index fibre (DCGIF) has been researched. New mechanism of the non-bridging oxygen hole centers (NBOHC) defect formation, conditioned by different mobility of diffusion counter flows of fluorine and oxygen at the core-cladding interface, has been proposed. Using silica tubes with 0.02 wt% of OH groups and hydrogen in free state in MCVD-technology of DCGIF fabrication completely eliminates the NBOHC absorption at the wavelength of 630 nm. However, gamma-irradiation of such fibres results in anomalously high attenuation level in the visible range of optical spectrum. It was established that irradiation of DCGIF leads to light scattering which is probably due to the appearance of optical inhomogeneities in the glass matrix.
关键词： fibre optics,Rayleigh scattering,fibre design and fabrication,radiation-resistant optical fibres
更新于2025-09-09 09:28:46
-
HW/SW co-design of a visual SLAM application
摘要： Vision-based advanced driver assistance systems (ADAS), appeared in the 2000s, are increasingly integrated on-board mass-produced vehicles, as off-the-shelf low-cost cameras are now available. But ADAS implement most of the time-specific and basic functionalities such as lane departure or control of the distance to other vehicles. Integrating accurate localization and mapping functionalities meeting the constraints of ADAS (high-throughput, low-consumption, and small-design footprint) would pave the way towards obstacle detection, identification and tracking on-board vehicles at potential high speed. While the SLAM problem has been widely addressed by the robotics community, very few embedded operational implementations can be found, and they do not meet the ADAS-related constraints. In this paper, we implement the first 3D monocular EKF-SLAM chain on a heterogeneous architecture, on a single System on Chip (SoC), meeting these constraints. In order to do so, we picked up a standard co-design method (Shaout et al. Specification and modeling of hw/sw co-design for heterogeneous embedded systems, 2009) and adapted it to the implementation of potentially any of such complex processing chains. The refined method encompasses a hardware-in-the-loop approach allowing to progressively integrate hardware accelerators on the basis of a systematic rule. We also have designed original hardware accelerators for all the image processing functions involved, and for some algebraic operations involved in the filtering process.
关键词： SLAM,ADAS,FPGA,Co-design,Machine-vision
更新于2025-09-09 09:28:46
-
Reference Module in Earth Systems and Environmental Sciences || Solar Energy in Buildings☆
摘要： Solar Energy can be utilized in many ways (e.g., photovoltaics, solar–thermal–electrical systems, solar ponds, and biomass conversion), but in the current chapter only applications associated with covering the heating and cooling requirements of buildings will be discussed. These applications require low or medium -temperature heat and include water heating, either for domestic hot water systems or swimming pools, space heating, and possibly also space cooling.
关键词： Net Zero Energy Buildings,Economics,Passive Systems,Design Methods,Thermal Behavior of Buildings,Buildings,Solar Energy,Solar Collectors,Space Heating and Cooling Systems,Hot Water Systems
更新于2025-09-09 09:28:46
-
Metamaterials - Devices and Applications || Development of Metamaterial EBG Absorbers for Application of Wireless Inter/Intrachip Communication Systems
摘要： First, the chapter presents a novel design of electromagnetic bandgap (EBG) absorber with the characteristics of broad bandwidth, low profile, and polarization‐independence to a normal incident electromagnetic wave. The absorber is composed of three consecutive octagon or decagon loops, and highly‐resistive frequency selective surface (FSS) layers. Second, based on the feature of the designed absorber unit, a broadband, meta‐material absorber‐bounded, wireless inter/intrachip (WIIC) communication channel is constructed at the center frequency of 60 GHz. Third, in order to validate the developed methodology used in WIIC analysis, a wired channel on a conventional PCB has been measured, simulated, and analyzed. Fourth, with the extracted S‐parameters of the WIIC system and wired PCB channel, the system impulse responses and transfer functions of the investigated channels have been further extracted, which are used for validation and BER analysis of the WIIC system. Finally, it has been shown that based on the derived BER results, the performance of the designed WIIC channel is close to that of an additive Gaussian white noise (AWGN) channel when the WIIC transceivers are built in with the functionalities of forward error control (FEC), channel estimation, and equalization.
关键词： metamaterial EBG,channel design,absorber,wireless inter/intra chip communication,bit error rate
更新于2025-09-09 09:28:46
-
[IEEE 2018 4th International Conference on Computer and Information Sciences (ICCOINS) - Kuala Lumpur (2018.8.13-2018.8.14)] 2018 4th International Conference on Computer and Information Sciences (ICCOINS) - Designing Page Scrolling Gesture using Gesture-Specific Heuristics in Leap Motion Validating The Gesture-Specific Heuristics By Creating Optimal Gestures
摘要： Optimal gesture creation is marred with many uncertainties, challenges and is still at its infancy stage. For hand-tracking devices such as that invented by Leap Motion, there is a lack of well-established gestures on controlling the operating system to perform basic operations. The gesture-specific heuristics (GSH) are a set of guidelines that could be used to evaluate and design gestures that would suit the limitation of the device and operating environment. This study narrows the gesture design to a single activity – simulating mouse wheel scrolling. However, the designing process comes with major obstacles. GSH needs to be supplemented with existing usability heuristics that tackles non-gestural design issues. The end results of combining GSH with existing usability heuristics produces a gesture that is more optimal than the existing available solutions. Moving forward, additional heuristics, taking into account user expectancy of the gesture nature needs to be considered.
关键词： mobile application,usability model,gesture interaction,gesture design
更新于2025-09-09 09:28:46
-
A Double-Cladding Single Polarization Photonic Crystal Fiber and Its Structure Deviation Tolerance
摘要： We propose a novel broadband single-polarization single-mode photonic crystal fiber (SPSM-PCF) with hexagonally latticed circular airholes. Combined with our fabricated polarization maintaining fiber, it has demonstrated that the enlarged air holes in the outmost layer are superior for the confinement loss reduction. At the optimized parameters, the wavelength of SPSM region is ranging from 1.52 μm to 2.13 μm, where only y-polarized fundamental mode exists and the confinement loss is 0.051 dB/km at 1.55 μm. The influence of realistic fabrication errors involving structure deviation on SPSM operation has also been systematically investigated.
关键词： fiber properties.,Fiber design and fabrication,photonic crystal fibers,single-polarization single mode
更新于2025-09-09 09:28:46