Abstract: A method to predict and fit an APC of a LEO satellite considering attitude information is provided, which includes: transforming a spacecraft body-fixed coordinate system, obtaining a transformation matrix from orbital coordinate system to transformed spacecraft body-fixed coordinate system, obtaining rotation angles during a rotation process, obtaining rotation angles in orbit determination time period to predict rotation angles in orbit prediction time period, obtaining a transformation matrix from spacecraft body-fixed coordinate system to Earth-fixed coordinate system of each prediction moment, obtaining a correction vector from a CoM to a phase center of a downlink signal antenna in the Earth-fixed coordinate system at each prediction moment, and obtaining an orbit of the phase center of the downlink signal antenna of a LEO satellite, and performing an ephemeris parameter fitting on the orbit of the phase center of the downlink signal antenna of the LEO satellite in a fitting time period.

Abstract: The technology described herein is directed towards designing and implementing multibeam metasurfaces, based on deriving the directions of grating lobes within a general rectangular grid structure. The derivation is used to design and implement multibeam metasurfaces. A multibeam metasurface is designed based on the directions of the grating lobes and desired beam splitting angles, which are used to determine unit cell/element grid characteristics of periodicity data and orientation. When deployed, the multibeam metasurface splits an impinging electromagnetic wave/beam in the desired multiple beam splitting directions. In one implementation, the multibeam metasurface is implemented in a single surface.

Abstract: A target identification method includes: obtaining an image containing a target to be identified; performing feature extraction on the image to obtain image features in the image; and inputting the image features into a target identification network model to obtain an identification result that determines a class to which the target to be identified belongs. The target recognition network model includes a loss function that is to constrain a first distance corresponding to each triplet in a number of triplets and a second distance corresponding to each triplet in the triplets. The first distance represents a distance between anchor image features and positive sample image features in each triplet in the triplets, and the second distance represents a distance between the anchor image features and a class center mean of a number of classes in each triplet in the triplets.

Abstract: A display panel has a display region and a non-display region, and the non-display region includes a second bendable region. The display panel includes a substrate, a first inorganic layer, an organic protection layer, a light-emitting function layer, an encapsulation layer, and a second inorganic layer. The second inorganic layer is disposed on a side of the encapsulation layer away from the substrate and extends from the display region to the non-display region and beyond a boundary of the encapsulation layer. A plurality of openings are provided in an edge part of the second inorganic layer away from the display region.

Abstract: The technology described herein is directed towards a design and implementation of a unit cell for a reconfigurable intelligent surface/reflectarray by incorporating reconfigurability within a phase-delay element of the unit cell. Reconfigurability is directly incorporated into the unit cell via a variable length phase delay line element and PCM-based (e.g., mmWave) phase shifter that determines the unit cell's phase shift by changing the length of the phase delay line element. One implementation is directed to a monolithic integration of the element using chalcogenide materials as switch elements with pulsed actuation to switch among different available lengths that determine the length of the phase delay line element, resulting in a significant reduction in power consumption, area saving, and digital reconfigurability.

Abstract: A human body information extraction method includes: obtaining a target image to be detected; performing shallow feature extraction on the target image by using a first feature extraction network in a preset human body information extraction model to obtain shallow features of the target image; performing deep feature extraction on the shallow features by using a second feature extraction network in the human body information extraction model to obtain deep features of the target image; performing multi-scale feature fusion on the shallow features and the deep features by using a feature fusion network in the human body information extraction model to obtain fused features of the target image; and performing a fully connected operation on the fused features by using a fully connected network in the human body information extraction model to obtain human body information corresponding to the target image.

Abstract: Disclosed herein are impedance-based biosensor systems comprising an impedance-based biosensor having an electrode, a meter in electrical communication with the electrode, a processor in electrical communication with the impedance-based biosensor and the meter, and a memory storing instructions to be executed by the processor. The instructions can cause the impedance-based biosensor system to measure the impedance of the electrode, derive one or more electrical properties of the impedance-based biosensor from the impedance of the electrode, and calculate a viable cell count based on the one or more electrical properties.

Abstract: The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via actuators, e.g., piezoelectric motors. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Moveable partitions in the resonators, controlled by piezoelectric actuators, facilitates changing of the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

Abstract: The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via heaters that change the internal temperatures of the resonators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A heater, controlled by a controller, facilitates changing of the air temperature in the unit cells to adjust the resonant frequencies thereof, to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

Abstract: The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the server's fan(s), with an opening in the frame structure to facilitate airflow therethrough, without obstructing or substantially obstructing the airflow to the surrounding environment.

Abstract: A time transfer method based on undifferenced and uncombined PPP-RTK is applied to a time transfer system including a PPP-RTK network end observation station network and PPP-RTK user end observation stations. The network end observation station network includes GNSS reference stations and a network data processing center. The user end observation stations include a time reference station and an ordinary user station. The method includes: acquiring GNSS observations collected by the GNSS reference stations and performing an undifferenced and uncombined PPP-RTK resolution to generate network end products; each of the user end observation stations performing an undifferenced and uncombined PPP-RTK resolution by using collected GNSS observations and the network end product to generate multi-GNSS receiver clock biases; and solving a combined inter-station clock bias by using the receiver clock biases of the ordinary user end observation stations and those of the time reference station serving also as user end.

Abstract: The technology described herein is directed towards a transceiver with beam scanning capability based on leaky wave antenna technology, which facilitates a compact transceiver design. The leaky wave antenna can be incorporated into a substrate integrated waveguide design, and can include different respective groups of slot pairs having different respective periodicities, corresponding to different respective beam steering directions. The transceiver can thus steer signals to a wearable or portable device that includes a passive metasurface while mitigating null regions; the transceiver transmits a wireless radio frequency signal towards the metasurface integrated into the wearable device, whereby the metasurface reflects an (e.g., metasurface-altered) instance of the incoming signal back to the transceiver. The receipt of the reflected signal can, for example, facilitate proximity detection of the user.

Abstract: The technology described herein is directed towards a transceiver with beam scanning capability based on leaky wave antenna technology and substrate integrated waveguide technology, along with a metallic covering that determines which direction the antenna radiates signals. The leaky wave antenna can include different respective groups of slot pairs having different respective periodicities, corresponding to different respective beam steering directions. One or more metallic covers can be used to cover some of the slot pair sections, such that the sections under cover behave like a conventional substrate integrated waveguide and the exposed section(s) behave like conventional leaky wave antennas. The metallic covers can be moved as desired, such as attached via magnets. The transceiver can thus steer signals to a wearable or portable device that includes a passive metasurface while mitigating null regions.

Abstract: The technology described herein is directed towards designing and deploying a wearable device that includes a passive metasurface of unit cells with a segmented ground plane of electrically separated segments. When the wearable device is worn, e.g., as a ring or wristband that contacts the wearer's skin, the wearer's skin conductivity electrically connects the separated segments to provide a ground plane. With a complete ground plane, the metasurface's unit cells resonate when exposed to a transmitted signal and reflect a distinct signature corresponding to a physical radiation pattern of signals reflected by the activated metasurface. When not worn, the metasurface is deactivated because of the electrically disconnected ground plane segments. Discontinuity parameters of size, position, and quantity of ground discontinuities are iteratively varied during modeling of a metasurface to determine the design with the largest difference in performance characteristics for when the device is worn versus not worn.

Abstract: A gesture recognition method, a gesture recognition device, an electronic device and a computer-readable storage medium are provided. The gesture recognition method includes steps: obtaining a reference feature vector set including M gesture categories and a gesture category set including M reference feature vectors, where each of the reference feature vectors is obtained by performing vector fusion on initial feature vectors of N sample images of each of the gesture categories, and the initial feature vectors are obtained by performing hand feature extraction on the sample images; performing hand feature extraction on the image to be recognized to obtain a gesture feature vector; and determining a target gesture category of the image to be recognized based on similarities between the gesture feature vector and the M reference feature vectors.

Abstract: The technology described herein is directed towards a metasurface for protection against high power electromagnetic (EM)/radio frequency signals, including at high frequencies. The metasurface unit cell design is based on using metal-insulator transition material (e.g., VO2) patch elements, which can be monolithically integrated during fabrication. At lower power levels, the VO2 patch elements are in a high resistance state, allowing inner and outer metal portions of a unit cell to resonate at a desired incoming frequency, thereby passing the signals through the metasurface. At a high power threshold level, determined by dimensions of the VO2 patch elements, the VO2 patch elements are in a low resistance state that couples the inner and outer metal portions into a single low resistance conductive surface that shields the signals from passing through the metasurface.

Abstract: A person re-identification method, a storage medium, and a terminal device are provided. In the method, a loss function used during model training is a preset distribution-based triplet loss function constraining a difference between a mean of a negative sample feature distance and a mean of a positive sample feature distance to be larger than a preset difference threshold; where the positive sample feature distance is a distance between a feature of a reference image, and a feature of a positive sample image, and the negative sample feature distance is a distance between the feature of the reference image and a feature of a negative sample image. In this manner, it can constrain the mean of the positive sample feature distance and that of the negative sample feature distance, thereby improving the accuracy of person re-identification results.

Abstract: Reminder methods, desks, devices, controllers, and computer program products are disclosed. The method includes determining the centroid of a user utilizing a desk by way of a millimeter-wave radar. The method further includes determining the posture of the user based on the centroid, and determining a first duration for which the user maintains the posture. The method also includes, in response to the first duration exceeding a time threshold, providing a reminder to the user. In this way, by calculating the centroid of a user utilizing the desk, the user's posture can be accurately determined, thereby enabling accurate reminders to be provided to the user.

Abstract: A method, an apparatus, a device and a medium for recommending data are provided. In a method, first feature data of an object is obtained. A permission type for using the first feature data is obtained, the permission type specifying a portion of the first feature data allowed to be used in data recommendation. The first feature data is updated based on the permission type to generate second feature data; and based on the second feature data, a group of data items matching the second feature data is determined from a data set including a plurality of data items.

Abstract: The technology described herein is directed towards a metasurface arranged with unit cells for broadband and/or multiband sound absorption, in which the unit cells are based on the principles of Helmholtz resonators. Deeply subwavelength sound absorbing unit cells are designed and constructed based on desired resonance frequencies. Each unit cell includes a neck portion and air chamber dimensioned to resonate at a desired resonance frequency and thereby inverse phase cancel corresponding frequencies of incoming sound waves. Differently designed and arranged subgroups of unit cells are part of the metasurface, which can be positioned proximate to a noise source. As practical examples, the metasurface or multiple metasurfaces can be placed near or wrapped around a computer server or rack of servers to absorb fan noise. The metasurface components (including the unit cells) can be printed by a 3D printer to result in a thin, light-weight, and cost effective noise absorbing metasurface.