Catálogo de publicaciones - libros

Most existing spreading models for network viruses are developed refereing to the epidemic models for biological viruses. However, Why most network viruses spread much slower than those models predicate? Why most network viruses still exist when they go beyond the threshold predicated by those models? Contrary to the prior models, the paper points out network viruses have different spreading features compared with biological viruses, such as the connectivity rate and cure rate are both functions of the time which are also key factors to affect the spreading of viruses. Based on which the paper constructs a more general epidemiological model for the network viruses. For several particular cases the paper presents the simulations of the connectivity rate and cure rate and find they are consistent well with the statistics of some real viruses. Thus the paper opens one path to modifying the traditional epidemic models.

In this paper, a novel optimal design method for PID controller is proposed based on the ant system (AS) algorithm. In this method, for a given control system with a PID controller, by taking the overshoot, settling time, and steady-state error of unit step response of the system as the performance indexes and using the AS algorithm, the optimal PID controller parameters , , and can be obtained. The proposed method has excellent features, including easy implementation, good convergence property, and efficient tuning of PID controller parameters. The PID controller designed using this method is called the AS-PID controller. In order to verify the good performance of the AS-PID controller, four typical control systems were tested. The simulation results show that the proposed method is indeed adaptive and robust in quick search of the optimal PID controller parameters.

This paper presents a novel approach for visual inspection of textures. The approach applies the artificial immune theory to learning the filters for texture flaw detection, which are invariant to changes of texture orientations and scales. In this paper, defect textures and defect-free textures are regarded as non-self and self respectively, and texture filters are regarded as antibodies. The clonal selection based algorithm is presented to evolve antibodies. Experimental results on TILDA textile images were done to show the feasibility of the proposed method.

A standard cell placement algorithm based on adaptive simulated annealing is presented in this paper. Considering the characters of different circuits to be placed, adaptively initial temperature and adaptive searching region are added to traditional simulated annealing algorithm. At the same time, the punishment item in objective function and initial placement approach are improved for the standard cell placement problem. This algorithm is applied to test a set of benchmark circuits, and experiments reveal its advantages in placement results and time performance when compared with the traditional simulated annealing algorithm.

A novel text watermarking algorithm is presented. It combines natural language watermarking and Chinese syntax based on BP neural networks. Since the watermarking signals are embedded into some Chinese syntactic structure rather than the appearance of text elements, the algorithm is totally based on the content that can prove to be very resilient. It will play an important role in protecting the security of Chinese documents over Internet.

The proposed method of text watermarking by exploits nouns and verbs in a sentence parsed with a grammar parser while using semantic networks. Change is done on the structure of the sentence to generate nouns and verbs whose non terminals, away from the root sentence are used with random numbers to hide the watermark. The modifications, range from active to passive voices or use of linking verbs or using mid-sentence modifiers, terminal modifiers to combining modifiers.

In this paper, we propose the steganalysis based on sequence synchronization analysis against chaos based spread spectrum image steganography (CSSIS). This method uses the correlation between the estimated chaotic sequences in two stegoimages to buildup synchronization measure, which can effectively detect the presence of CSSIS. Based on the analysis, a more secure method is presented, which is constructed on key transmission channel (KTC). This improved method uses the stochastic modulation to realize the steganography. It avoids the sequences synchronization fault in CSSIS by randomly choosing the parameters of chaotic map, which is proved by the experimental results.

Multisensory fusion is being increasing viewed as an important activity in the filed of mobile robot navigation and obstacle avoidance. The fusion of data from a variety of sensors makes the mobile robot more easily survival in a hostile environment. It takes advantage of the redundancy and reciprocity of multisensory data and increases the precision and reliability of inference and judgment for the mobile robot. This paper presents a method which employs fuzzy logic and neural networks to fuse data from several kinds of sensors. As a result, more exact navigation and quick obstacle avoidance can be achieved.

Current techniques used to detect hacker intrusion are postmortem in that they get into action only if someone or something is intruding, in other words, they are reactionary. This paper proposes a PDE-based intrusion forecast model that aims to forecast hacker intrusion before they actually occur.

Hierarchical convolutional neural networks are a well-known robust image-recognition model. In order to apply this model to robot vision or various intelligent real-time vision systems, its VLSI implementation is essential. This paper proposes a new algorithm for reducing multiply-and-accumulation operation by sorting neuron outputs by magnitude. We also propose a VLSI architecture based on this algorithm. We have designed and fabricated a sorting LSI by using a 0.35 m CMOS process. We have verified successful sorting operations at 100 MHz clock cycle by circuit simulation.