Applied Mechanics and Materials Vols. 143-144

Abstract: Sparse representation of signals has many important applications in signal processing. However, this issue is well known as a complex and NP problem, which is a key factor to depress the application and progress of sparse decomposition. In this work, seeker optimization algorithm(SOA)- based method is used to search for the best matching atoms in sparse decomposition. For comparision, the conventional matching pursuit (MP) method and two versions of PSO algorithms are also consid- ered in the simulation studies. The simulation results show that the proposed approach is an effective and reliable technique for time-frequency atom decomposition.

Abstract: By the use of "cut and suture" algorithm and the introduction of control points, a three-dimensional entity creation algorithm was proposed, with the characteristics of the local flat taken into account. This method cut the adjacent contour lines into two parallel line segments through the automatic search of feature contour's control points (or human interaction selection). After the construction of unconstrained Delaunay triangulation network on the basis of lines' planar points, line sections were sutured from the incisions, followed by the completion the three-dimensional entity surface reconstruction of contours. The multi-layers ore profile data based on drilling geological interpretation were tested. The results show that this algorithm is fast and reliable. The reconstructed three-dimensional surface is smooth and natural, similar to the actual surface morphology.The method bears a practical merit for assisting the interpretation of three-dimensional geological forms in geological survey.

Abstract: Considering the fitness of each individual, a hybrid intelligence algorithm is established, which combine the excellent probing ability of free search algorithm (FS) with exploiting ability of invasive weed optimization algorithm (IWO). The hybrid algorithm can overcome the disadvantage of lower optimization rate in late evolution for FS and taking advantage of powerful exploiting abilities for IWO. Identity between FS and IWO is analyzed and convergence of the two algorithms in solving continuous function optimization is provided. Simulations confirmed the analysis. Multi-model Shubert function is chosen to carry out the simulation. Compared with FS and IWO, the hybrid algorithm is superior in convergence speed and robustness.

Abstract: Active-control algorithms such as optimal control or impulse control methods generally achieve satisfactory control effectiveness, but it often fails to control dynamic systems with time-delay effectively. In view of this reason, a novel active controller using Genetic Algorithm (GA) is proposed in this paper, which is based on discrete motion equation of multi-freedom degree system with time delay. It can solve such subsistent problems as effective control for a seismically excited structure with an explicit time delay. Meanwhile it is also prone to achieve a desired vibration state in accordance with different control objectives. Finally in order to verify its validity, the GA controller are applied to a three-storey and a eight-storey structures excited by different seismic forces, numerical examples of which are given to prove it capable of providing satisfactory control effect with time delay.

Abstract: According the present complicated and lacks of high-leveled automation ground operation supporting system, based on the concept of ICAO'S A-SMGCS (advanced surface movement guidance and control systems) and the existed facilities of the airport, this paper focuses on the research of a new ground operation supporting system in accordance with A-SMGCS, including the basis system hardware, the surveillance ground monitoring subsystem and the lighting subsystem, etc. The system is capable of not only detecting and predicting the traffic conflicts on the ground but also providing solutions and suggestions. Meanwhile the system can help controllers to arrange and use the airport resources so as to reduce the ground holding time and delay time.

Abstract: With the explosive use of internet, contemporary web servers are susceptible to overloads during which their services deteriorate drastically and often lead to denial of services. Many companies are trying to address this problem using multiple web servers with a front-end load balancer. Load balancing has been found to provide an effective and scalable way of managing the ever-increasing web traffic. Load balancing is one of the central problems that have to be solved in parallel queueing web server system. To analyze load balancing this paper presents a queueing system that has two web servers. Firstly the centralized load balancing system is considered. The next, two routing policies are studied, the average response time and the rejection rate are derived. Finally some of our results are further considered.

Abstract: In order to improve the dynamic servo performance of PMLSM, a classical direct torque control (DTC) scheme based on bang-bang control is proposed in the paper. The proposed control method uses the bang-bang hysteresis controller formed a dual-closed loop control system, it contains torque loop and flux loop. The DTC control model was established and the simulation experiment was made. The simulation experiment results show that the DTC can improve the dynamic performance of PMLSM. It can reduce the ripples of speed and torque, so that it can provide more precision and accuracy servo performance.

Abstract: In this paper, we study the attitude control problems based on model of spherical pendulum. Three degrees of freedom pendulum (3D pendulum) is a rigid body supported by a frictionless pivot. According to relative position of the center of mass and the fixed pivot without friction, the 3D rigid pendulum can be divided into two balanced attitudes, Hanging equilibrium and inverted equilibrium. For the axisymmetric 3D rigid pendulum, the axis of symmetry is equivalent to axis of inertia of rigid body, and angular velocity around the axis of symmetry is equal to zero, as a result, the 3D rigid pendulum can be equal to the spherical pendulum. According to the motion attitude of spherical pendulum, one control method based on passive theory is proposed in this paper, Firstly, we use the passive theory to research the equilibrium stability of spherical pendulum. Secondly, passive theory and the Lyapunov function are utilized to deduce the control law .Finally, the spherical pendulum reach asymptotically stable in equilibrium position.

Abstract: A novel control approach is introduced for strict-feedback nonlinear systems based on the dynamic equilibrium state theory. First, the basic idea of the dynamic equilibrium state theory is presented. The dynamic equilibrium state is not the origin or the constant, but means change under the effect of input for non-free systems. Then, the method of steady state control is combined with backstepping technology, realizing the feedback linearization and stability step by step and guaranteeing uniform ultimate boundedness of all signals in the closed-loop system. The proposed approach has much simpler expression and is easy to understand. Finally, two simulation examples are used to demonstrate the effectiveness of the proposed scheme.

Abstract: The differential equation(physical model) is derived based on giving the structure and working principle of some micro-gyroscope. The sense and drive equations are solved for analyzing the basic working laws. According to the form of the solutions the motion form is analyzed, and further the performances are analyzed from the view of range, sensitivity, bandwidth, linearity, zero bias and other indicators, and provided theoretical basis for to improve the gyroscope design.