Showing papers by "Xidian University published in 1990"
01 Aug 1990
TL;DR: An approach for recognition of a planar polygon from a single 2-D perspective projection using the basic viewpoint invariant cross-ratio (CR) is presented and the shape CR-descriptor of a spatial planarpolygon, i.e. the CR sequence extracted from its single projective image is proposed.
Abstract: An approach for recognition of a planar polygon from a single 2-D perspective projection using the basic viewpoint invariant cross-ratio (CR) is presented. The shape CR-descriptor of a spatial planar polygon, i.e. the CR sequence extracted from its single projective image, is proposed. The minimum mean square error is used as the matching criterion. Examples are given. The approach can be directly applied to the recognition and motion analysis of 3-D objects that contain planar polygons. >
46 citations
TL;DR: A new digital signature scheme based on error-correcting codes is proposed, which can be combined with the McEliece public-key cryptosystem, and obtained that cannot only sign, but also encipher, messages.
Abstract: A new digital signature scheme based on error-correcting codes is proposed. The security of this scheme relies on the difficulty of factoring large matrices and the properties of error-correcting codes. The features of the author's scheme are that the ciphertext for a given message M is not repeated and errors in the ciphertext received can be detected and corrected. If this scheme is combined with the McEliece public-key cryptosystem, a scheme is obtained that cannot only sign, but also encipher, messages.
42 citations
TL;DR: Analysing the possible stable state of the system is based on both the flowrate rule and the invariability in volume satisfied by the potential and shows that the neural system with fluid properties is well-done to intelligence search problem.
Abstract: Hopfield presented a neural network with continuous states, associated with an analogue circuit (1984). On the condition that the weights keep
$$T_{ii} = - \sum {_{j
e i} {\text{T}}_{ij} }$$
and
$$T_{ii} = T_{ji} \geqslant 0$$
for i≠j, the potential u
iof the neurons in the system can be of the properties like those of fluid and the communication among neurons is the result of the flowing of the potential like the flowing of fluid (ideal liquid) affected only by gravity. This means that the flowing of the potential among neurons is from higher level to lower level and that the cause for the varing of a neuron in its state is due to that the net input flowrate of all the potential to the neuron is nonzero. Therefore, the system has a quite clear convergent process and, has a unique stable state. Analysing the possible stable state of the system is based on both the flowrate rule and the invariability in volume satisfied by the potential. The experiment of solving labyrinthian puzzle shows that the neural system with fluid properties is well-done to intelligence search problem.
28 citations
6 citations
16 Jun 1990
TL;DR: A novel effective regional descriptor based on the normalized rapid descriptor (NRD) and regional projections is presented, which is significantly superior to the normalized Fourier descriptor (NFD) in computational speed and storage requirement.
Abstract: A novel effective regional descriptor based on the normalized rapid descriptor (NRD) and regional projections is presented. The NRD is significantly superior to the normalized Fourier descriptor (NFD) in computational speed and storage requirement. The proposed descriptor was used for shape analytical experiments for several types of synthesized images. The descriptor was applied to the target recognition of four sequential images varying in size and orientation relative to the sensor. The results show that the descriptor is quite effective. >
5 citations
TL;DR: The main purpose of as discussed by the authors is to give a numerical analysis for the electric field of the Spindt device using the boundary element method, where the boundary integral equation and the fundamental solution of the field are derived.
4 citations
01 Aug 1990
TL;DR: Some errors in a paper by Wong et al. on the effects of random sensor motion on bearing estimation by the MUSic algorithm are corrected and the theoretical performance prediction of the MUSIC algorithm under the condition of random sensors motion is given.
Abstract: Some errors in a paper by Wong et al. on the effects of random sensor motion on bearing estimation by the MUSIC algorithm are corrected and the theoretical performance prediction of the MUSIC algorithm under the condition of random sensor motion is given.
3 citations
TL;DR: In this paper, the reliability of the reflector accuracy of the parabolic antenna under the action of random wind load is analyzed by means of the theory of reliability, and a corresponding computer program is designed, with which an 8m-diameter paraboloid antenna structure is calculated as an illustration.
2 citations
31 Oct 1990
TL;DR: The authors report on their work to introduce the reflective architecture in a popular compilation-based language, C++, without modifying the compiler, which provides a disciplined split between the object level and the meta-object level in a class-based form.
Abstract: The authors report on their work to introduce the reflective architecture in a popular compilation-based language, C++, without modifying the compiler. The reflective architecture provides a disciplined split between the object level and the meta-object level in a class-based form. The unit of causal connections is the class member function. Mechanisms based on the methods diversion are constructed to support a kind of implicitly causal connection. A delegation mechanism is constructed for sharing meta-methods whose classes are not designed as having inheritance. A prototype has been constructed in the Advantage C++ 1.1 M4 running on MSDOS. >
2 citations
27 Mar 1990
TL;DR: In this article, a series of accelerated life tests, with high-temperature storage and electric ageing, for NPN silicon planar transistors is discussed, and it was found that at low current the current gain h/sub FE/ increases with time during the tests, and its drift is correlated with initial measured 1/f noise in the transistors.
Abstract: A series of accelerated life tests, with high-temperature storage and electric ageing, for NPN silicon planar transistors is discussed. It was found that at low current the current gain h/sub FE/ increases with time during the tests, and its drift is correlated with initial measured 1/f noise in the transistors. The correlation coefficient of relative drift Delta h/sub FE//h/sub FE/ and 1/f noise spectral density Si/sub B/(f) is far larger than that of Delta h/sub FE//h/sub FE/ and other initial DC parameters. A quantitative theory for the h/sub FE/ drift which can satisfactorily explain the h/sub FE/ drift characteristics in the tests is discussed. The model proves that h/sub FF/ drift and 1/f noise can be attributed to the same physical origin. Both are caused by the modulation of carrier traps near the Si-SiO/sub 2/ interface leading to Si surface recombination. 1/f noise measurement, therefore, can be used as a fast and nondestructive tool to predict h/sub FE/ instability of bipolar transistors. >
2 citations
TL;DR: An adaptive dummy spectrum insertion method which is applied to the asynchronous analogue–digital–analogue (ADA) speech scrambler greatly improves the security of the scrambler, and maintains good speech quality.
Abstract: An adaptive dummy spectrum insertion method which is applied to the asynchronous analogue–digital–analogue (ADA) speech scrambler is presented. Related analysis and computer simulation results are given. Both analysis and simulation results indicate that the method greatly improves the security of the scrambler, and maintains good speech quality.
01 Mar 1990
TL;DR: The Fourier transforms in finite fields and the concept of linear complexity of sequences are described and new theorems about the lower bounds of the minimum distance of cyclic codes are obtained.
Abstract: Firstly, the Fourier transforms in finite fields and the concept of linear complexity of sequences are described. Then several known lower bounds on the minimum distance of cyclic codes are outlined. Finally, the minimum distance of cyclic codes is analyzed via linear complexity of sequences, and new theorems about the lower bounds are obtained.
TL;DR: The sparse matrix technique in the device simulation can decrease, storage greatly with less CPU time and its implementation is very easy.
Abstract: A novel sparse matrix technique for the numerical analysis of semiconductor devices and its algorithms are presented. Storage scheme and calculation procedure, of the sparse matrix are described in detail. The sparse matrix technique in the device simulation can decrease, storage greatly with less CPU time and its implementation is very easy. Some algorithms and calculation examples to show the time and space characteristics of the sparse matrix are given.
TL;DR: Results indicate that II-HARQ using DC code gives a good throughput efficiency and some DC codes which have a better DDS than KM codes are designed and Hadamard transform decoding is regarded as a common decoding method.
Abstract: The letter gives general descriptions of II-GHARQ and defines a concept of minimum distance distributed sequence (DDS) which is more exact to represent the error-correcting capability of the codes used in II-GHARQ. Some DC codes which have a better DDS than KM codes are designed and Hadamard transform decoding is regarded as a common decoding method. Both analysis and simulation results indicate that II-HARQ using DC code gives a good throughput efficiency.
03 Apr 1990
TL;DR: An algorithm is developed to reconstruct the two-dimensional (2-D) image of the surface plane or section plane of an object from reflected signal data when a sensor moves along a straight-line path.
Abstract: An algorithm is developed to reconstruct the two-dimensional (2-D) image of the surface plane or section plane of an object from reflected signal data when a sensor moves along a straight-line path. It is considered as a tomographic imaging problem from arc projections. The principle of tomographic imaging is introduced and an imaging algorithm is derived. Computer simulation results are given. The imaging algorithm may be applied to radar imaging for a partial terrain area, and to reflection mode ultrasonic computerized tomography. >