HYDRAULIC CHARACTERISTICS OF WATER-WINGS FOR THE MIDDLE-PIER OF A DISCHARGE TUNNEL

1. INTRODUCTION In the design of a discharge tunnel with high water head and large flow, it is important to study the cavitation and the energy dissipation, such as the prevention of cavitation for slots of various gates [1-4], the effects of entrained ai…     

消失模铸造模成型机的特点及应用

介绍了消失模铸造工艺对成型机的特殊要求,高性能成型机在大规模工业化消失模生产中的重要性,重点阐述了德国Teubert公司TVY130/90消失模成型机的特点及应用,并对成型机的国产化研究与开发提出了建议。     

Seismic Physical Modeling Technology and Its Applications

1. Introduction Seismic physical modeling technology is an important method for the research on seismic exploration theory and methods. In seismic physical experiments, the earth, mantle or field site are scaled down to physical models according to the similarity principle, and then the seismic field and its variation are observed in the laboratory for the research work on the theories and methods of the earth structure, earthquake forecasting, energy and mineral resource exploration, and engi…     

Morphology control of titanium oxides by tetramethylammonium cations in hydrothermal conditions

The effect of tetramethylammonium cations (TMA⁺) on TiO₂ crystal morphology in hydrothermal conditions has been studied. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The morphologies including besom-like particle, nanosheet and nanotube have been observed. The different ways TMA⁺ cations in the hydrothermal bases affect the crystal growth manner are suggested to be responsible for the different morphologies of the as-synthesized samples.     

A novel approach to detecting DDoS Attacks at an Early Stage

Distributed Denial-of-Service (DDoS) attacks pose a serious threat to Internet security. Most current research focuses on detection and prevention methods on the victim server or source side. To date, there has been no work on defenses using valuable information from the innocent client whose IP has been used in attacking packets. In this paper, we propose a novel cooperative system for producing warning of a DDoS attack. The system consists of a client detector and a server detector. The client detector is placed on the innocent client side and uses a Bloom filter-based detection scheme to generate accurate detection results yet consumes minimal storage and computational resources. The server detector can actively assist the warning process by sending requests to innocent hosts. Simulation results show that the cooperative technique presented in this paper can yield accurate DDoS alarms at an early stage. We theoretically show the false alarm probability of the detection scheme, which is insensitive to false alarms when using specially designed evaluation functions. This work is partially supported by HK Polyu ICRG A-PF86 and CERG Polyu 5196/04E, and by the National Natural Science Foundation of China under Grant No. 90104005.     

基于RBF网络和IMM的机动目标跟踪方法

文中提出了一种应用RBF神经网络对标准IMM算法中的卡尔曼滤波结果进行校正的方法。网络输人为预测误差、卡尔曼增益以及测量值与估计值之差．网络输出反映了由于目标机动所带来的滤波误差．将网络输出结果和直接由卡尔曼滤波求解得到的结果相加．可以得到更为准确的滤波值。同时．在网络的学习算法中．在网络权值矩阵的修正公式中增加了反映滤波残差的调整项．若卡尔曼滤波的残差较大，网络调整权值的幅度也相应增大。仿真结果表明．在目标发生机动转弯处．校正后的IMM算法的跟踪误差要明显小于标准IMM算法的跟踪误差．跟踪精度较高。     

不复杂也尊贵--手表装饰工艺

它们贯穿手表内外．机芯已经不是它们唯一的居处。当机械痴谜者还沉醉于复杂的机芯时．你是否发现它们的踪影？一只陀飞轮万年历能够清楚地让你知道钱的去向．但除了这些．手表装饰也可以使表的价值迅速窜升。这也可以说是进入高级手表的门槛．[编者按]     

人-车-路虚拟仿真中人机交互模块开发

使用VisualC++6.0作为开发平台,论述了基于VegaAPI的人-车-路系统虚拟仿真中人机交互的实现原理,使用Di-rectX的DirectInput组件,实现了在主线程中转向、制动、加速等人机交互驾驶操作信号的读取,并给出了主要的伪代码实现。     

与国际接轨积极开展国际间贯标认证工作创国际品牌

论述了中国的金、银生产企业在中国加入世界贸易组织(WTO)和黄金、白银市场放开的形势下开展国际间认证的必要性，介绍了内蒙古乾坤金银精炼股份有限公司开展各项认证的经险和体会。