Abstract: Provided are a direction of arrival (DOA) estimation method and system for a sparse array based on Vandermonde decomposition reconstruction, relating to the technical field of array signal processing. The method includes: constructing a covariance matrix completion optimization model based on sparse array signals and uniform linear array signals, and performing Vandermonde decomposition by using characteristics of a uniform linear array; introducing a nuclear norm to optimize a rank function in the model, and updating the covariance matrix completion optimization model; and introducing an auxiliary variable to transform the model into a solvable optimization problem, and solving the problem by an alternating direction multiplier method to obtain an optimal estimation value. The DOA is estimated using a root multiple signal classification algorithm.

Abstract: Provided are a direction of arrival (DOA) estimation method and system for a sparse array based on Vandermonde decomposition reconstruction, relating to the technical field of array signal processing. The method includes: constructing a covariance matrix completion optimization model based on sparse array signals and uniform linear array signals, and performing Vandermonde decomposition by using characteristics of a uniform linear array; introducing a nuclear norm to optimize a rank function in the model, and updating the covariance matrix completion optimization model; and introducing an auxiliary variable to transform the model into a solvable optimization problem, and solving the problem by an alternating direction multiplier method to obtain an optimal estimation value. The DOA is estimated using a root multiple signal classification algorithm.

Abstract: A DoA estimation method and device based on steering vector matrix reconstruction, related to the field of array signal processing. The method includes: obtaining an array sampling covariance matrix according to an array received signal; setting a target variable, and limiting a feasible domain of the target variable by using two operators to determine a first constraint condition; characterizing an estimation error based on the target variable and the array sampling covariance matrix, and using the characterized estimation error as a second constraint condition; establishing an initial optimization model according to a preset norm based on partial sum of singular values and constraint conditions of the target variable; determining a multivariable optimization model according to the initial optimization model; and solving the multivariable optimization model to obtain an optimal result; analyzing the optimal result to obtain a DoA of the target incident signal.

Abstract: A DoA estimation method and device based on steering vector matrix reconstruction, related to the field of array signal processing. The method includes: obtaining an array sampling covariance matrix according to an array received signal; setting a target variable, and limiting a feasible domain of the target variable by using two operators to determine a first constraint condition; characterizing an estimation error based on the target variable and the array sampling covariance matrix, and using the characterized estimation error as a second constraint condition; establishing an initial optimization model according to a preset norm based on partial sum of singular values and constraint conditions of the target variable; determining a multivariable optimization model according to the initial optimization model; and solving the multivariable optimization model to obtain an optimal result; analyzing the optimal result to obtain a DoA of the target incident signal.

Abstract: A battery cell appearance defect detection apparatus may comprise: a first detection assembly comprising a first image collector and a first light source, wherein the first light source emits first light, the first light forming a first included angle with a detection surface, and the first image collector collects a first image of the position on the battery cell irradiated by the first light; a second detection assembly comprising a second image collector and a second light source, wherein the second light source emits second light, the second light forming a second included angle with the detection surface, and the second image collector collects a second image of the position on the battery cell irradiated by the second light, with the second included angle being less than the first included angle; and a control assembly constructed to detect appearance defects of the battery cell.

Abstract: An electronic apparatus that includes a first port configured to receive an incoming audio signal, a second port, and a controller configured to be coupled to the first port and the second port. The electronic apparatus further includes a switch configured to selectively decouple the controller from the second port when the first port receives the incoming audio signal. Decoupling the controller prevents an electrostatic discharge occurring on the second port from reaching the controller when the controller is receiving the incoming audio signal from the first port.

Abstract: A method and apparatus for sign-bill return based on a blockchain, a device and a readable storage medium, through acquiring (S101) a sign-bill return request sent by a shipment terminal; acquiring (S102) pre-stored target sign-bill information according to the sign-bill return request; acquiring (S103) a target hash value corresponding to the target sign-bill information from the blockchain; and sending (S104) the target sign-bill information to the shipment terminal, when verifying that the target sign-bill information is correct by the target hash value, the tamper-proof blockchain storage of the target sign-bill information is achieved, which not only improves efficiency of the sign-bill return, but also improves reliability of the sign-bill return.

Abstract: An electronic apparatus that includes a first port configured to receive an incoming audio signal, a second port, and a controller configured to be coupled to the first port and the second port. The electronic apparatus further includes a switch configured to selectively decouple the controller from the second port when the first port receives the incoming audio signal. Decoupling the controller prevents an electrostatic discharge occurring on the second port from reaching the controller when the controller is receiving the incoming audio signal from the first port.

Abstract: A light spot arrangement, a surface profile measuring method and a method for calculating control data for an exposure field are disclosed. The light spot arrangement includes a plurality of measuring light spots (100) which define at least one set of orthogonal line segments, wherein the measuring light spots (100) lying on the orthogonal line segments radiate outward from a center, with each of the orthogonal line segments defined by at least four measuring light spots. With this light spot arrangement comprising at least one set of orthogonal line segments defined by measuring light spots radiating outward from a center, readings of multiple ones of the light spots (100) can be acquired in real time, and exposure can be performed with real-time focusing and leveling based on a surface profile of the wafer (200) derived from a surface fitting process carried out on the readings.

Abstract: A light spot arrangement, a surface profile measuring method and a method for calculating control data for an exposure field are disclosed. The light spot arrangement includes a plurality of measuring light spots (100) which define at least one set of orthogonal line segments, wherein the measuring light spots (100) lying on the orthogonal line segments radiate outward from a center, with each of the orthogonal line segments defined by at least four measuring light spots. The measuring light spots (100) are used to measure a profile of a planer surface. With this light spot arrangement comprising at least one set of orthogonal line segments defined by measuring light spots radiating outward from a center, readings of multiple ones of the light spots (100) can be acquired in real time, and exposure can be performed with real-time focusing and leveling based on a surface profile of the wafer (200) derived from a surface fitting process carried out on the readings.

Abstract: A method and a system for identifying a file type. A modification interface may be provided so that a user inputs a file feature parameter, and the file feature parameter input by the user is added to a file type configuration file, then the file type configuration file is loaded to a state machine to perform file type identification. Therefore, the user can modify a file feature parameter in the original file type configuration file, and when a file feature parameter of a file of a certain type is changed or a file of a new type appears, the user can update a file feature parameter in the state machine in time to identify the changed file or the file of the new type. In this way, the user does not need to search for an identification tool on the Internet.

Abstract: A method and a system for identifying a file type. A modification interface may be provided so that a user inputs a file feature parameter, and the file feature parameter input by the user is added to a file type configuration file, then the file type configuration file is loaded to a state machine to perform file type identification. Therefore, the user can modify a file feature parameter in the original file type configuration file, and when a file feature parameter of a file of a certain type is changed or a file of a new type appears, the user can update a file feature parameter in the state machine in time to identify the changed file or the file of the new type. In this way, the user does not need to search for an identification tool on the Internet.

Abstract: A method for identifying a file type and an apparatus for identifying a file type, so as to solve a problem in the prior art that a file type cannot be effectively identified when a sender tampers with a file being transmitted. The method includes: acquiring, from a transmitted data packet, a file header of a file to be identified, and determining whether a magic number can be obtained from the file header; if the magic number can be obtained, searching for the file type that corresponds to the magic number; determining whether data of the file to be identified complies with a data structure feature of the file type; if yes, determining that a file type of the file to be identified is the file type that corresponds to the magic number; and if not, determining that a file type of the file is an abnormal type.