Abstract: Disclosed are a temporary plugging agent and a preparation method thereof, and a method for temporary plugging and fracturing of a high-temperature reservoir. The temporary plugging agent includes the following components in mass fractions: acrylamide 5%, composite crosslinking agent 1%, laponite 1%, ammonium persulfate 0.1% and water 92.9%.

Abstract: An image processing method is provided. In the method, a target video frame set is acquired from video data of a plurality of video frames. The target video frame set includes a subset of the video frames that is selected based on characteristics of the subset of the video frames. A global color feature of a reference video frame is acquired. An image semantic feature of the reference video frame is acquired. An enhancement parameter of the reference video frame is acquired for each of at least one image information dimension according to the global color feature and the image semantic feature. Image enhancement is separately performed on the video frames in the target video frame set according to each enhancement parameter of the reference video frame to obtain target image data for each of the video frames in the target video frame set.

Abstract: Systems, methods, apparatuses, and computer program products for providing an anti-piracy framework for Deep Neural Networks (DNN). A method may include receiving authorized raw input at a protective transform module. The method may also include receiving unauthorized raw input at a restrictive deep neural network. The method may further include processing the authorized raw input at the protective transform module to generate a processed input. In addition, the method may include feeding the processed input into the restrictive deep neural network. The method may also include generating a result based on the processed input and the unauthorized raw input. Further, the result may include a different learning performance between the authorized raw input and the unauthorized raw input.

Abstract: Systems, methods, apparatuses, and computer program products for tracking weak signal traces under severe noise and/or distortions. A method may include tracking at least one candidate frequency trace from a time-frequency representation of a signal. The method may also include identifying a frequency trace of the signal based on tracking results. In addition, the method may include outputting an estimated frequency vector related to the frequency trace. Further, the tracking may be performed under a noisy condition environment.

Abstract: An apparatus for vital sign extraction. The apparatus may receive a vital signal of a subject from a sensing device. The apparatus may also perform a preprocessing procedure on the vital signal via bandpass filtering and normalization to obtain a preprocessed signal. The apparatus may also perform a time-frequency analysis of the preprocessed signal, and estimate a heart rate of the subject from a dominant component of the preprocessed signal by finding location of a maximum spectral energy of the time-frequency analysis. In addition, the apparatus may identify guard components in the preprocessed signal in view of the dominant component, and derive a respiratory rate of the subject from a length of an interval between the dominant component and each of the guard components.

Abstract: The present disclosure relates to a training method of a denoising model, an image denoising method and device. The training method includes: obtaining a plurality of to-be-denoised sample images; for each of the to-be-denoised sample images, obtaining a priori knowledge information corresponding to noise in the to-be-denoised sample image; for each of the to-be-denoised sample images, constructing a model training sample based on the to-be-denoised sample image and the a priori knowledge information; training a denoising model based on the model training samples to obtain a target denoising model for removing noise in image.

Abstract: Systems, methods, apparatuses, and computer program products for contact-free heart rate monitoring and/or measurement are provided. One method may include receiving video(s) that include visual frame(s) of individual(s) performing exercises, detecting some exposed skin from the video(s), and performing motion compensation to generate color signals for the exposed skin to precisely align frames of the exposed skin. The method may also include generating the color signals by estimating a skin color for each frame by taking a spatial average over pixels of a cheek of the face(s) for R, G, and B channels, respectively, applying an operation to remove remaining motion traces from the frames such that the heart rate traces dominate, and extracting and/or outputting the heart rate of the individuals using a frequency estimator of the skin color signals.

Abstract: Methods and devices for magnetic resonance imaging are provided. In one aspect, a method includes: obtaining undersampled k-space data as first partial k-space data by scanning a subject in an accelerated scanning manner, generating a first image by performing image reconstruction for the first partial k-space data according to a trained deep neural network and an explicit analytic solution imaging algorithm, obtaining mapped data of complete k-space by mapping the first image to k-space, extracting second partial k-space data from the mapped data of complete k-space, the second partial k-space data being distributed in the k-space at a same position as the first partial k-space data in the k-space, obtaining a residual image by performing image reconstruction according to the first partial k-space data and the second partial k-space data, and finally generating a magnetic resonance image of the subject by adding the first image with the residual image.

Abstract: Systems, methods, apparatuses, and computer program products for providing an anti-piracy framework for Deep Neural Networks (DNN). A method may include receiving authorized raw input at a protective transform module. The method may also include receiving unauthorized raw input at a restrictive deep neural network. The method may further include processing the authorized raw input at the protective transform module to generate a processed input. In addition, the method may include feeding the processed input into the restrictive deep neural network. The method may also include generating a result based on the processed input and the unauthorized raw input. Further, the result may include a different learning performance between the authorized raw input and the unauthorized raw input.

Abstract: Methods and devices for magnetic resonance imaging are provided. In one aspect, a method includes: obtaining undersampled k-space data as first partial k-space data by scanning a subject in an accelerated scanning manner, generating a first image by performing image reconstruction for the first partial k-space data according to a trained deep neural network and an explicit analytic solution imaging algorithm, obtaining mapped data of complete k-space by mapping the first image to k-space, extracting second partial k-space data from the mapped data of complete k-space, the second partial k-space data being distributed in the k-space at a same position as the first partial k-space data in the k-space, obtaining a residual image by performing image reconstruction according to the first partial k-space data and the second partial k-space data, and finally generating a magnetic resonance image of the subject by adding the first image with the residual image.

Abstract: A self-oscillating flyback converter includes a controller integrated circuit housed in a 3-pin package. A switch control terminal is coupled to the base of an inductor switch that controls the current through a primary inductor of the converter. The controller IC adjusts the on time of the switch such that output current remains constant in constant current mode and output voltage remains constant in constant voltage mode. A signal received on a switch control terminal turns the switch off and provides an indication of the output current when the switch is on. A signal received on a feedback terminal powers the controller IC and provides an indication of the output voltage when the switch is off. The controller IC is grounded through a ground terminal. The flyback converter transitions from critical conduction mode to discontinuous conduction mode at light loads to prevent its efficiency from deteriorating at high switching frequencies.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: A primary side controlled power converter having a voltage sensing means coupled to a transformer of the power converter and configured to provide a voltage feedback waveform representative of an output of the transformer is provided. A primary switching circuit operates to control energy storage of a primary side of the transformer. The primary switching circuit is operable during an on time and inoperable during an off time. The on and off time is switched at a system frequency. A feedback amplifier generates an error signal indicative of a difference between the voltage feedback waveform and a reference voltage. A sample and hold circuit samples the error signal at a periodic frequency during the off time. An error signal amplifier is configured to provide the sampled value to the primary switching circuit wherein the primary switching circuit controls the transformer and thereby regulates an output of the power converter.

Abstract: A self-oscillating flyback converter includes a controller integrated circuit housed in a 3-pin package. A switch control terminal is coupled to the base of an inductor switch that controls the current through a primary inductor of the converter. The controller IC adjusts the on time of the switch such that output current remains constant in constant current mode and output voltage remains constant in constant voltage mode. A signal received on a switch control terminal turns the switch off and provides an indication of the output current when the switch is on. A signal received on a feedback terminal powers the controller IC and provides an indication of the output voltage when the switch is off. The controller IC is grounded through a ground terminal. The flyback converter transitions from critical conduction mode to discontinuous conduction mode at light loads to prevent its efficiency from deteriorating at high switching frequencies.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: A primary side controlled power converter having a voltage sensing means coupled to a transformer of the power converter and configured to provide a voltage feedback waveform representative of an output of the transformer is provided. A primary switching circuit operates to control energy storage of a primary side of the transformer. The primary switching circuit is operable during an on time and inoperable during an off time. The on and off time is switched at a system frequency. A feedback amplifier generates an error signal indicative of a difference between the voltage feedback waveform and a reference voltage. A sample and hold circuit samples the error signal at a periodic frequency during the off time. An error signal amplifier is configured to provide the sampled value to the primary switching circuit wherein the primary switching circuit controls the transformer and thereby regulates an output of the power converter.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: A lower-cost and more precise control methodology of regulating the output voltage of a flyback converter from the primary side is provided, which works accurately in either continuous voltage mode (CCM) and discontinuous mode (DCM), and can be applied to most small, medium and high power applications such cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant voltage flyback converter.

Abstract: A lower-cost and more precise control methodology of regulating the output current of a Flyback converter from the primary side is provided. The methodology regulates the output current accurately in both continuous current mode (CCM) and discontinuous mode (DCM) and can be applied to most small, medium, and high power applications such as cell phone chargers, power management in desktop computers and networking equipment, and, generally, to a wide spectrum of power management applications. Two highly integrated semiconductor chips based on this control methodology are also described that require very few components to build a constant current Flyback converter.