Abstract: A zero-watermarking method and device for BIM data, and a medium are provided, which relate to the field of watermarking information security technologies. Aiming at existing zero-watermarking method for the BIM data cannot resist primitive attacks, vertical stability of a model is used to construct a mapping relationship between primitive clusters and watermarking bits, calculate norms of primitives in each primitive cluster of the primitive clusters, take positivity and negativity of norm skewness measurement of the primitives as eigenvalues to construct a binary sequence, and performs an XOR process on the binary sequence and an original watermarking sequence to construct the zero-watermarking for the BIM data. Experimental results indicate that the zero-watermarking method has uniqueness, robustness and security.

Abstract: A method for developing an epoxy resin impregnated glass fiber Direct Current (DC) bushing, comprising: according to length parameters of each layer of capacitive screen or resistive screen designed depending on insulation requirements, selecting bushing design parameters, determining a winding machine program according to the bushing design parameters, and winding a core body according to the winding machine program, wherein during the core body winding process, the core body begins to be initially cured; after the core body is wound, curing the core body by an oven according to a preset oven temperature and duration; machining the cured core body according to a preset core body design drawing; after the inner wall of a flange is polished and cleaned and is heated and pretreated by the oven, injecting glue at the position of a glue injection hole of the flange for gluing the core body and the flange; sequentially assembling a collector ring, a hollow composite insulator, and a voltage-equalizing sealing cove

Abstract: A dual watermarking method for trajectory data based on robust watermarking and fragile watermarking uses an encryption algorithm to construct robust watermark information, and then a farthest pair of feature points in a minimum convex hull of is set as constant points. Further quantization index modulation technology is used to embed robust watermark information into angles constructed from feature points and constant points. Finally, the angles and distance ratios constructed by trajectory points and constant points are used to group trajectory points. Within each group, spatiotemporal attributes of the trajectory points are taken as fragile watermark bits to be embedded in the distance ratios constructed by the trajectory points. A process of watermark detection is consistent with the embedding of watermark information. Watermarks embedded in the trajectory data based on the dual watermarking method have high robustness against translation, rotation, and scaling attacks.

Abstract: A watermarking method for a high-definition map based on invisible characters includes: firstly, establishing mapping relations between invisible characters and bit characters, a space character, and decimal digits; and combining watermark characters with corresponding positions thereof, adding Hamming code into a watermark character sequence, and converting the watermark character sequence into invisible characters to construct a composite watermark character sequence. Before watermark detection, a sequence of elements in map data is scrambled according to logistic chaotic mapping, and then the composite watermark character sequence is embedded according to the scrambled sequence. During watermark detection, the data are preprocessed, a sequence during watermark embedding is obtained, and then watermark information is extracted, errors are corrected, and an error correcting code is removed after correction to obtain final watermark information.

Abstract: A generation method of zero watermarking for trajectory data, a detection method of zero watermarking for trajectory data, a generation device of zero watermarking for trajectory data, a detection device of zero watermarking for trajectory data, and a storage medium are provided. The generation method divides a trajectory based on a coordinate system constructed by trajectory feature points of trajectory data into blocks, and then the moment invariants of trajectory in each block are used to construct a watermark sequence, which can achieve copyright protection without modifying the trajectory data. In addition, since the generation method uses moment invariants which can represent overall features of the trajectory to construct the watermark sequence, the generation method has strong stability in the face of common attacks and can resist almost all common types of attacks.

Abstract: A method for developing an epoxy resin impregnated glass fiber Direct Current (DC) bushing, comprising: according to length parameters of each layer of capacitive screen or resistive screen designed depending on insulation requirements, selecting bushing design parameters, determining a winding machine program according to the bushing design parameters, and winding a core body according to the winding machine program, wherein during the core body winding process, the core body begins to be initially cured; after the core body is wound, curing the core body by an oven according to a preset oven temperature and duration; machining the cured core body according to a preset core body design drawing; after the inner wall of a flange is polished and cleaned and is heated and pretreated by the oven, injecting glue at the position of a glue injection hole of the flange for gluing the core body and the flange; sequentially assembling a collector ring, a hollow composite insulator, and a voltage-equalizing sealing cove