A deformable surface model for real-time water drop animation

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.     

Short-term load forecasting using bayesian neural networks learned by Hybrid Monte Carlo algorithm

This paper presents a short term load forecasting model based on Bayesian neural network (shorted as BNN) learned by the Hybrid Monte Carlo (shorted as HMC) algorithm. The weight vector parameter of the Bayesian neural network is a multi-dimensional random variable. In learning process, the Bayesian neural network is considered as a special Hamiltonian dynamical system, and the weights vector as the system position variable. The HMC algorithm is used to learn the weight vector parameter with respect to Normal prior distribution and Cauchy prior distribution, respectively. The Bayesian neural networks learned by Laplace algorithm and HMC algorithm and the artificial neural network (ANN) learned by the BP algorithm were used to forecast the hourly load of 25 days of April (Spring), August (Summer), October (Autumn) and January (Winter), respectively. The roots mean squared error (RMSE) and the mean absolute percent errors (MAPE) were used to measured the forecasting performance. The experimental result shows that the BNNs learned by HMC algorithm have far better performance than the BNN learned by Laplace algorithm and the neural network learned BP algorithm and the BNN learned by HMC has powerful generalizing capability, it can welly solve the overfitting problem.     

Robust H ∞ control of uncertain nonlinear switched systems using constructive method

This paper focuses on the problem of robust H _?? control of nonlinear switched systems with parameter uncertainty via the multiple Lyapunov functions (MLFs) approach. The uncertain parameters are assumed to be in a known compact set and are allowed to enter the system nonlinearly. Based on the explicit construction of Lyapunov functions, which avoids solving the Hamilton-Jacobi-Isaacs (HJI) inequalities, sufficient conditions for the solvability of the robust H _?? control problem of cascade nonlinear switched systems are derived under some switching signal. Then, the result is extended to solve the robust H _?? control problem of nonlinear switched systems in strict feedback form. Finally, the effectiveness of the proposed results is illustrated through a simulation example.     

FD—140型高灵敏测氡仪及其应用

FD—140型高灵敏测氡仪用于测量氡的浓度,测氡灵敏度可达15mBq/m~3 min。该仪器可用于普查与勘探铀矿床,也可用于找石油、煤、金、地下水和地震预报以及地质构造调查等方面。     

基于CDMA的停车场车位引导系统设计

本文介绍了基于CDMA的停车场车位引导系统的设计方案,阐述了系统软硬件设计、CDMA主要特点及接口电路图。该系统采用CDMA无线通信模块,使系统性能更加完善。实验结果表明本系统与485通信系统、CAN总线通信系统相比,通信距离和通信速率明显提高。本系统避免了一路出错导致整个系统瘫痪的问题,使停车场车位引导系统更加智能化。     

项目管理在IT企业中的推广与应用

现阶段传统的管理模式还是一些中小型IT企业的主要管理方式。这种方式导致很多中小型IT企业发展的新旧项目成功率都很小。所以,在当前情况下,要大大加强项目管理的涉及度,使之进入中小IT企业。从而,提高中小企业的核心竞争力。那么什么IT企业,何为项目管理,项目管理在IT企业中的推广应用,以及二者之间的相互关系就是我们研究的重要课题。     

组态王和VB在远程定位中的应用

为了利用组态王6.53接收远程数据功能和VB(Visual Basic)对MapX控件进行二次开发功能,利用DDE(Dynamic Data Exchange)技术,实现了组态王6.53与VB通信,根据组态王通信使用的MODBUS协议格式和GPS(Global Positioning System)数据格式,来提取经纬度信息,以此控制动态图层中的图元,来而实现远程车辆的定位,同时也扩大了监控中心软件的功能。     

PTA氧化过滤干燥系统典型问题及对策

介绍了精对苯二甲酸(PTA)装置氧化过滤干燥系统存在的典型问题,系统分析了产生这些问题的原因,并提出相应的对策。     

Damping forced oscillations in power system via interline power flow controller with additional repetitive control

With the continuous expansion of power systems and the application of power electronic equipment, forced oscillation has become one of the key problems in terms of system safety and stability. In this paper, an interline power flow controller (IPFC) is used as a power suppression carrier and its mechanism is analyzed using the linearized state-space method to improve the system damping ratio. It is shown that although the IPFC can suppress forced oscillation with well-designed parameters, its capability of improving the system damping ratio is limited. Thus, combined with the repetitive control method, an additional repetitive controller (ARC) is proposed to further dampen the forced power oscillation. The ARC control scheme is characterized by outstanding tracking performance to a system steady reference value, and the main IPFC controller with the ARC can provide higher damping, and further reduce the amplitude of oscillations to zero compared with a supplementary damping controller (SDC). Simulation results show that the IPFC with an ARC can not only greatly reduce the oscillation amplitude, but also actively output the compensation power according to the reference value of the ARC tracking system.