Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse...Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.展开更多
A subset S of V is called a k-connected dominating set if S is a dominating set and the induced subgraph S has at most k components.The k-connected domination number γck（G） of G is the minimum cardinality taken ove...A subset S of V is called a k-connected dominating set if S is a dominating set and the induced subgraph S has at most k components.The k-connected domination number γck（G） of G is the minimum cardinality taken over all minimal k-connected dominating sets of G.In this paper,we characterize trees and unicyclic graphs with equal connected domination and 2-connected domination numbers.展开更多
Image forensics is a form of image analysis for finding out the condition of an image in the complete absence of any digital watermark or signature.It can be used to authenticate digital images and identify their sour...Image forensics is a form of image analysis for finding out the condition of an image in the complete absence of any digital watermark or signature.It can be used to authenticate digital images and identify their sources.While the technology of exemplar-based inpainting provides an approach to remove objects from an image and play visual tricks.In this paper, as a first attempt, a method based on zero-connectivity feature and fuzzy membership is proposed to discriminate natural images from inpainted images.Firstly, zero-connectivity labeling is applied on block pairs to yield matching degree feature of all blocks in the region of suspicious, then the fuzzy memberships are computed and the tampered regions are identified by a cut set.Experimental results demonstrate the effectiveness of our method in detecting inpainted images.展开更多
Abstract：A space-filling polyhedron is a polyhedron which ＇tile＇ space, analogous to the way of certain polygons tiled the plane. The cube is the unique space-filling platonic solid. If we make line connections the...Abstract：A space-filling polyhedron is a polyhedron which ＇tile＇ space, analogous to the way of certain polygons tiled the plane. The cube is the unique space-filling platonic solid. If we make line connections the center with the vertices in the certain cube, the cube is divided into six pyramids. And if we glued six pyramids to the faces of the cube, we obtain a ＇rhombic dodecahedron＇. Since cubes are packing a space, rhombic dodecahedra are also space-filling polyhedra and a rhombic dodecahedron is divided into two regular tetrahcdra and one regular octahedron. In this study, we present how rhombic dodecahedron can be split into tetrahedra and octahedron. In this process, we can research a variety of divisions of regular polyhedron.展开更多
In this paper, we conduct research on the accurate computer music composition mode under the basic background of big data. From the perspective of music theory, in terms of micro notes jump within a certain range, wil...In this paper, we conduct research on the accurate computer music composition mode under the basic background of big data. From the perspective of music theory, in terms of micro notes jump within a certain range, will not cause discomfort, notes there are upward at the same time, the downward makes the whole piece will not boring. From the macroscopic, the nature of the chord with internal connection between motivation and motivation as support, at the same time, the whole range can maintain in a certain range, making sound effects is can let a person feel cheerful. Computer science first occupied is music in the music sound production and the propagation of position as it is mainly used for digital audio clips and automated synthesis. But there is a certain distance away from the traditional concept of composition. Therefore, our research proposes the innovative perspective to deal with the issues for achieving the better performance.展开更多
The author＇s proposal is to show how an apparently marginal text by Walter Benjamin, ＂The Destructive Character＂, can be taken as a hermeneutic model for understanding the connection of Benjamin＇s with history and...The author＇s proposal is to show how an apparently marginal text by Walter Benjamin, ＂The Destructive Character＂, can be taken as a hermeneutic model for understanding the connection of Benjamin＇s with history and tradition and for characterizing his thought as philosophy of threshold. It is the author＇s intention to show how the destructive character, on the threshold between destruction and construction, succeeds in remaining in that transition area that announces a change, showing its creative and conservative features; thus it appears as a figure of coexistence between stillness and movement, passage and interruption, and past and future. What the author wants to point out is that, in the description of this figure, Benjamin is driven by a cognitive demand, which tends to focalize the process of destruction itself rather than the result of the destruction process. The space in which the destructive character is acting is the space of the possibility of change and emancipation, and the space where it is possible to keep together past and future, and memory and redemption. Starting from these reflections, an important question arises about the problem of the relation between history and tradition, and culture and its memory： Neither the destruction of memory by a culture nor its canonization is meaningful. The concept of destructive character then represents a preferential point of observation for analyzing the articulations of Benjamin＇s thought. From this perspective, a decisive point of Benjamin＇s reflection seems to emerge on one side, strengthened in the permeation of Hebraic ancestors between destruction and salvation; on the other side, some of the concepts and images of the Berliner philosopher seem to show up in a new light.展开更多
Objective For computer-aided Chinese medical diagnosis and aiming at the problem of insufficient segmentation,a novel multi-level method based on the multi-scale fusion residual neural network(MF2ResU-Net)model is pro...Objective For computer-aided Chinese medical diagnosis and aiming at the problem of insufficient segmentation,a novel multi-level method based on the multi-scale fusion residual neural network(MF2ResU-Net)model is proposed.Methods To obtain refined features of retinal blood vessels,three cascade connected UNet networks are employed.To deal with the problem of difference between the parts of encoder and decoder,in MF2ResU-Net,shortcut connections are used to combine the encoder and decoder layers in the blocks.To refine the feature of segmentation,atrous spatial pyramid pooling(ASPP)is embedded to achieve multi-scale features for the final segmentation networks.Results The MF2ResU-Net was superior to the existing methods on the criteria of sensitivity(Sen),specificity(Spe),accuracy(ACC),and area under curve(AUC),the values of which are 0.8013 and 0.8102,0.9842 and 0.9809,0.9700 and 0.9776,and 0.9797 and 0.9837,respectively for DRIVE and CHASE DB1.The results of experiments demonstrated the effectiveness and robustness of the model in the segmentation of complex curvature and small blood vessels.Conclusion Based on residual connections and multi-feature fusion,the proposed method can obtain accurate segmentation of retinal blood vessels by refining the segmentation features,which can provide another diagnosis method for computer-aided Chinese medical diagnosis.展开更多
The current massive use of digital communications demands a secure link by using an embedded system（ES） with data encryption at the protocol level. The serial peripheral interface（SPI） protocol is commonly used by...The current massive use of digital communications demands a secure link by using an embedded system（ES） with data encryption at the protocol level. The serial peripheral interface（SPI） protocol is commonly used by manufacturers of ESs and integrated circuits for applications in areas such as wired and wireless communications. We present the design and experimental implementation of a chaotic encryption and decryption algorithm applied to the SPI communication protocol. The design of the chaotic encryption algorithm along with its counterpart in the decryption is based on the chaotic Hénon map and two methods for blur and permute（in combination with DNA sequences）. The SPI protocol is configured in 16 bits to synchronize a transmitter and a receiver considering a symmetric key. Results are experimentally proved using two low-cost dsPIC microcontrollers as ESs. The SPI digital-to-analog converter is used to process, acquire, and reconstruct confidential messages based on its properties for digital signal processing. Finally, security of the cryptogram is proved by a statistical test. The digital processing capacity of the algorithm is validated by dsPIC microcontrollers.展开更多
The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the form...The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the former gets analytic expression; the latter depends on heavy numerical calculation,which contains uncertainty.By using connection of fiber bundles,this paper establishes an analytic formula for the latter,and the numerical work is simplified.It shows the mathematical structure of molecule is fiber bundle.展开更多
An ultra-highly precise and long-term stable frequency transmission system over 120 km commercial fiber link has been proposed and experimentally demonstrated. This system is based on digital output compensation techn...An ultra-highly precise and long-term stable frequency transmission system over 120 km commercial fiber link has been proposed and experimentally demonstrated. This system is based on digital output compensation technique to suppress phase fluctuations during the frequency transmission process. A mode-locked erbium-doped fiber laser driven by a hydrogen maser serves as an optical transmitter. Moreover, a dense wavelength division multiplexing system is able to separate forward and backward signals with reflection effect excluded. The ultimate fractional frequency instabilities for the long-distance frequency distributed system are up to 3.14×10^(-15) at 1 s and 2.96×10^(-19) at 10 000 s, respectively.展开更多
基金The National Natural Science Foundation of China(No.50575140)
文摘Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.
文摘A subset S of V is called a k-connected dominating set if S is a dominating set and the induced subgraph S has at most k components.The k-connected domination number γck（G） of G is the minimum cardinality taken over all minimal k-connected dominating sets of G.In this paper,we characterize trees and unicyclic graphs with equal connected domination and 2-connected domination numbers.
文摘Image forensics is a form of image analysis for finding out the condition of an image in the complete absence of any digital watermark or signature.It can be used to authenticate digital images and identify their sources.While the technology of exemplar-based inpainting provides an approach to remove objects from an image and play visual tricks.In this paper, as a first attempt, a method based on zero-connectivity feature and fuzzy membership is proposed to discriminate natural images from inpainted images.Firstly, zero-connectivity labeling is applied on block pairs to yield matching degree feature of all blocks in the region of suspicious, then the fuzzy memberships are computed and the tampered regions are identified by a cut set.Experimental results demonstrate the effectiveness of our method in detecting inpainted images.
文摘Abstract：A space-filling polyhedron is a polyhedron which ＇tile＇ space, analogous to the way of certain polygons tiled the plane. The cube is the unique space-filling platonic solid. If we make line connections the center with the vertices in the certain cube, the cube is divided into six pyramids. And if we glued six pyramids to the faces of the cube, we obtain a ＇rhombic dodecahedron＇. Since cubes are packing a space, rhombic dodecahedra are also space-filling polyhedra and a rhombic dodecahedron is divided into two regular tetrahcdra and one regular octahedron. In this study, we present how rhombic dodecahedron can be split into tetrahedra and octahedron. In this process, we can research a variety of divisions of regular polyhedron.
文摘In this paper, we conduct research on the accurate computer music composition mode under the basic background of big data. From the perspective of music theory, in terms of micro notes jump within a certain range, will not cause discomfort, notes there are upward at the same time, the downward makes the whole piece will not boring. From the macroscopic, the nature of the chord with internal connection between motivation and motivation as support, at the same time, the whole range can maintain in a certain range, making sound effects is can let a person feel cheerful. Computer science first occupied is music in the music sound production and the propagation of position as it is mainly used for digital audio clips and automated synthesis. But there is a certain distance away from the traditional concept of composition. Therefore, our research proposes the innovative perspective to deal with the issues for achieving the better performance.
文摘The author＇s proposal is to show how an apparently marginal text by Walter Benjamin, ＂The Destructive Character＂, can be taken as a hermeneutic model for understanding the connection of Benjamin＇s with history and tradition and for characterizing his thought as philosophy of threshold. It is the author＇s intention to show how the destructive character, on the threshold between destruction and construction, succeeds in remaining in that transition area that announces a change, showing its creative and conservative features; thus it appears as a figure of coexistence between stillness and movement, passage and interruption, and past and future. What the author wants to point out is that, in the description of this figure, Benjamin is driven by a cognitive demand, which tends to focalize the process of destruction itself rather than the result of the destruction process. The space in which the destructive character is acting is the space of the possibility of change and emancipation, and the space where it is possible to keep together past and future, and memory and redemption. Starting from these reflections, an important question arises about the problem of the relation between history and tradition, and culture and its memory： Neither the destruction of memory by a culture nor its canonization is meaningful. The concept of destructive character then represents a preferential point of observation for analyzing the articulations of Benjamin＇s thought. From this perspective, a decisive point of Benjamin＇s reflection seems to emerge on one side, strengthened in the permeation of Hebraic ancestors between destruction and salvation; on the other side, some of the concepts and images of the Berliner philosopher seem to show up in a new light.
基金Key R&D Projects in Hebei Province(22370301D)Scientific Research Foundation of Hebei University for Distinguished Young Scholars(521100221081)Scientific Research Foundation of Colleges and Universities in Hebei Province(QN2022107)。
文摘Objective For computer-aided Chinese medical diagnosis and aiming at the problem of insufficient segmentation,a novel multi-level method based on the multi-scale fusion residual neural network(MF2ResU-Net)model is proposed.Methods To obtain refined features of retinal blood vessels,three cascade connected UNet networks are employed.To deal with the problem of difference between the parts of encoder and decoder,in MF2ResU-Net,shortcut connections are used to combine the encoder and decoder layers in the blocks.To refine the feature of segmentation,atrous spatial pyramid pooling(ASPP)is embedded to achieve multi-scale features for the final segmentation networks.Results The MF2ResU-Net was superior to the existing methods on the criteria of sensitivity(Sen),specificity(Spe),accuracy(ACC),and area under curve(AUC),the values of which are 0.8013 and 0.8102,0.9842 and 0.9809,0.9700 and 0.9776,and 0.9797 and 0.9837,respectively for DRIVE and CHASE DB1.The results of experiments demonstrated the effectiveness and robustness of the model in the segmentation of complex curvature and small blood vessels.Conclusion Based on residual connections and multi-feature fusion,the proposed method can obtain accurate segmentation of retinal blood vessels by refining the segmentation features,which can provide another diagnosis method for computer-aided Chinese medical diagnosis.
基金Project supported by the CONACYT,México(No.166654)
文摘The current massive use of digital communications demands a secure link by using an embedded system（ES） with data encryption at the protocol level. The serial peripheral interface（SPI） protocol is commonly used by manufacturers of ESs and integrated circuits for applications in areas such as wired and wireless communications. We present the design and experimental implementation of a chaotic encryption and decryption algorithm applied to the SPI communication protocol. The design of the chaotic encryption algorithm along with its counterpart in the decryption is based on the chaotic Hénon map and two methods for blur and permute（in combination with DNA sequences）. The SPI protocol is configured in 16 bits to synchronize a transmitter and a receiver considering a symmetric key. Results are experimentally proved using two low-cost dsPIC microcontrollers as ESs. The SPI digital-to-analog converter is used to process, acquire, and reconstruct confidential messages based on its properties for digital signal processing. Finally, security of the cryptogram is proved by a statistical test. The digital processing capacity of the algorithm is validated by dsPIC microcontrollers.
文摘The evolution of electronic states in molecule has two origins: dynamical one produced by Schr¨odinger equation and kinematical one caused by base transformation due to nuclear motion.In current theories,the former gets analytic expression; the latter depends on heavy numerical calculation,which contains uncertainty.By using connection of fiber bundles,this paper establishes an analytic formula for the latter,and the numerical work is simplified.It shows the mathematical structure of molecule is fiber bundle.
基金supported by the National Natural Science Foundation of China(Nos.61571244 and 61501262)the Science and Technology Project of Tianjin(No.16YFZCSF00540)the Natural Science Foundation of Tianjin(No.15JCYBJC51600)
文摘An ultra-highly precise and long-term stable frequency transmission system over 120 km commercial fiber link has been proposed and experimentally demonstrated. This system is based on digital output compensation technique to suppress phase fluctuations during the frequency transmission process. A mode-locked erbium-doped fiber laser driven by a hydrogen maser serves as an optical transmitter. Moreover, a dense wavelength division multiplexing system is able to separate forward and backward signals with reflection effect excluded. The ultimate fractional frequency instabilities for the long-distance frequency distributed system are up to 3.14×10^(-15) at 1 s and 2.96×10^(-19) at 10 000 s, respectively.
