Advanced Materials Research Vols. 204-210

Abstract: A single model can hardly describe all viruses because computer viruses replicate in a variety of ways. Therefore, this paper proposes a model, which is based on multiple characteristics of the virus. Traditional models cannot effectively reflect the characteristics and process of computer virus propagation. This paper presents a new virus propagation model to describe the spread of viruses in the network environment. By solving the model equations, running data analyses, and conducting simulation experiments, this study collected the actual statistical data and compared them with the experimental data. The result indicates that the model can effectively reflect the characteristics of the spread of the virus. Therefore, this model provides a scientific basis for the computer virus prevention.

Abstract: This paper studies the design of robust H∞ controller for stochastic wind power generation systems. Assuming the system is convex uncertain，this article presents the H∞ performance criterion for uncertain stochastic system , deduces sufficiency conditions of the existence of H∞ controller with state feedback, and expresses them into a form of the linear matrix inequality (LMI), then utilizes schur complement lemma to transform them into LMIs which can be solved. At last we utilize standard digital software to get the disturbance attenuation level and the state feedback matrix.

Abstract: Multicast delivery has become more and more important in modern multimedia applications for broadband satellites over ATM networks. Multimedia integrates texts, audios, videos and still images in a variety of applications. The data in this media can be time critical in terms of maximum delay and delay jitter. In order to satisfy all these applications, the network needs to have an efficient multicasting mechanism using the true capability of ATM networks. In this paper, a bi-directional multipoint-to-multipoint multicast model was proposed for broadband multimedia satellites over ATM networks, which uses a single tree for a multicast group consisting of multiple participants that are either senders, receivers, or a mix of both. We first discuss why the resequencer model will not be suitable for multimedia traffics, then propose the model to solve the problems. The mean queueing delays of our model are not sensitive to mean size of the data packet while the mean queueing delays and of the resequencer model are very sensitive to mean size of the data packet.

Abstract: To detect and receive the high dynamic and high information-rate signal for communication platform in the stratosphere, it is necessary to design digital system to acquire and track the carrier. In the high dynamic and high information-rate situation, the most important aspect is the great influence of Doppler frequency shift and high information rate on the carrier acquisition and track. Carrier acquisition and track in the high dynamic and high information-rate situation was implemented by means of the combination of FPGA and frequency, phase lock loop. A new algorithm using DQPSK for carrier acquisition and track was proposed and the validity of the design and algorithm was proved by means of trials and comparison with EKF method in the high dynamic and high information-rate situation.

Abstract: In service networks, the location of servers and allocation of demand nodes to them have a strong impact on the congestion at each server. The previous efforts in this area have concentrated on enhancing the reliability and quality of service with a probabilistic and fuzzy orientation. This paper considers the uncertain nature of such services and utilizes uncertainty theory to develop an uncertain queuing maximal covering location-allocation model. Our model considers one type of service call, one type of server and includes one constraint on the quality of queue length. To solve the proposed model, we design a hybrid intelligent algorithm which integrates 99-method and differential evolution algorithm. Finally, a numerical example is performed to show the application of the model and the algorithm.

Abstract: It is proposed the method based on particle movement to simulate flow in this paper. The force on particles can be obtained from N-S equations, and the calculation error caused by particles’ simulation is discussed. Results show that the method is more effective through the example of flow field affected by the cube. The advantage of this method is to solve problems of multiphase flow and fluid-structure interaction.

Abstract: The reconfiguration technology of CNC system is divided into two interactive levels: hardware system reconfiguration and software system reconfiguration. The hardware system reconfiguration is based on a rapid field programming of Field which is performed with different FPGA configuration files. Meanwhile, software system reconfiguration is conducted through design, modification, selection and configuration of different databases on a guiding software reconfiguration development platform. Then, the software-hardware co-design of the system reconfiguration is discussed. Finally, an application case of aforementioned reconfiguration methods is given. A CNC system with 5 synchronously moveable axes in total 8 stepping axes is reconfigured successfully from the existing CNC system with 3 synchronously moveable axes in 4 ones.

Abstract: This paper developed an EOQ model, in which the demand follows a general distribution, under the assumption that lead time can be shortened and setup cost can be reduced by added investment, and backorder rate depends on inventory level and price discount in the period of shortage. We proved the existence and uniqueness of optimal solution and proposed an algorithm searching for it. We find that order quantity, safety stock and inventory total cost can be normally reduced by shortening lead time and reducing setup cost, furthermore, backordering parameter and probability of shortage have a great impact on inventory total cost, so an enterprise should do its best to reduce probability of shortage, especially when backordering parameter is small.

Abstract: Maximum likelihood estimation is a very popular method to estimate the independent component analysis model because of good performance. Independent component analysis algorithm (the natural gradient method) based on this method is widely used in the field of blind signal separation. It potentially assumes that the source signal was symmetrical distribution, in fact in practical applications, source signals may be asymmetric. This article by distinguishing that the source signal is symmetrical or asymmetrical, proposes an improved natural gradient method based on symmetric generalized Gaussian model (People usually call generalized Gaussian model) and asymmetric generalized Gaussian model. The random mixed-signal simulation results show that the improved algorithm is better than the natural gradient separation method.

Abstract: The Smart Antenna which can adaptively track the user signals plays an important role in reducing the interferences among users in TD-SCDMA. This paper focuses on the study of the smart antenna adaptive beam-forming algorithm and aims at realizing the design and emulation of it by using the least mean square algorithm (LMS) and the recursive least squares algorithm (RLS). And by the comparison and analysis of the result, we want to learn its effectiveness in reducing the interferences in TD-SCDMA system.