Berezin symbol and invertibility of operators on the functional Hilbert spaces

We give in terms of reproducing kernel and Berezin symbol the sufficient conditions ensuring the invertibility of some linear bounded operators on some functional Hilbert spaces.     

OFDM的原理及技术特点

正交频分复用(OFDM)是一种新型调制技术,特别适合在多径传播的无线移动信道中高速传输数据。本文简要介绍了OFDM的发展概况和基本原理,以及调制、同步等几个关键技术,最后概述了OFDM技术的优点及不足之处。     

基于模拟电感的混沌同步电路的研究

介绍了3种有源模拟电感电路，以及他们在混沌同步电路中的应用，最后对其性能进行了比较。通过仿真研究，证实模拟电感可以代替混沌电路中实际的电感，而不影响其性能，既可以使电感元件在电路中实现集成化，又有利于解决混沌同步电路对初值敏感的缺点，因此有着非常广泛的应用前景。     

A Novel OFDM Timing Offset Estimation Algorithm

1　Introduction　OrthogonalFrequencyDivisionMultiplexing(OFDM )isamethodsuitableforhigh ratedatatransmissioninwirelesscommunications .However,thereareseverallimitingfactorsinthecommercialapplicationofOFDMforapplyingtohigh ratemo bilecommunication ,suchasDopplerfrequencyshift,synchronization ,channelestimation ,peak to averagepowerratio .　Schmidl[1 ] completedsynchronizationusingspecialPNsequence,buttheestimateisnot precise.Minn[2～ 3] andByungjoon[4] improvethealgorithmperformance,butth…     

分布式对象缓存框架设计研究

对象缓存是一种通过在使用对象后不立即释放，而是存储在内存或硬盘中并被后来的客户端请求重用，避免重新建立对象的昂贵成本的机制。在考查了业界广泛使用的几种对象缓存框架后，提出了一种分布式对象缓存框架的设计方案LiteCS。该框架中服务器不需要负责对象更改消息的传递，即使缓存对象被频繁地修改，也不会大大增加系统的整体负载，可有效降低网络负荷．现所做的两组测试证明了LiteCS框架适用于多台服务器通过网络共享缓存对象。     

A new explicit expression of the Contou-Carrère symbol

The aim of this note is to offer a new explicit expression of the Contou-Carrère symbol that depends only on a product of a finite number of terms. As an application, we obtain an explicit formula for a Witt Residue.

     

Experimental observation of direct current voltage-induced phase synchronization

The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.     

Games of timing related to distribution of resources

The paper considers a class of zero-sum, two-person games which are related to distribution of resources. Each of the players is in possession of an amount of resource, to be distributed by him in the time interval [0, 1] according to an arbitrary measure. The payoff function is defined in such a manner that the games are a generalization of the so-called silent, nondiscrete duels. It is proven that these games have a value, and the optimal strategies for the players are found. The results of the paper bring to light new, essential elements, common to almost all games of timing on [0, 1].     

实现混沌系统同步的非线性状态观测器方法

针对一类状态不能全部测量且含有不确定因素的混沌系统的同步问题，设计了一个带有控制器的非线性观测器.当系统的非线性项满足一定条件时，不论系统是处于平衡点、周期、拟周期、混沌或超混沌状态，都可使观测器的状态按照目标系统给定的轨道演化，并且是大范围内可同步的.计算机仿真结果表明了所提出方法的有效性. 关键词： 状态观测器 混沌 超混沌 同步     

Synchronization of ultraviolet-preionization in a Marx-driven TEA CO2 laser

In a TEA CO₂ laser a two-stage spark gap was used to control the predischarge, which produced the ultraviolet-preionization, and to generate a trigger pulse for the Marx bank, which excited the main discharge. The time-sequence of the predischarge and the trigger pulse could be reversed so that the main discharge could commence before the preionization process. This set-up has enabled temporal synchronization on the laser performance, or basically the time delay between the pre- and the main discharges, to be investigated from about − 150 ns to 600 ns.