A New Primary Lazy Update Propagation Protocol for Replicated Databases

This paper proposes a new primary lazy update protocol, PTCS （Primary Transaction Commit Schedule）. In the PTCS protocol, a serializable primary transaction schedule is generated firstly and then the secondary transactions are committed according to the serializable primary transaction schedule. PTCS protocol can guarantee serializability if the data copy graph contains no directed circles. It can also be ex tended to eliminate all requirements on the data copy graph. Compared to earlier works, PTCS protocol not only imposes a much weaker requirement on the data placement, but also avoids the deadlock caused by transaction waits and extra message overhead. The performance experiments show that the degradation of the performance caused by the replica man- agement of the PTCS protocol is tolerable.     

An Energy-Aware Routing Protocol Based on Effective Transmission in Sensor Networks

In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission （ET） that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.     

A TTP-Independent Watermarking Protocol Based on Commutative Cryptosystem for Copyright Protection in E-Commerce

For the purpose of deterring unauthorized duplication and distribution of multimedia contents in e-commerce, some Buyer-seller watermarking protocols which combine of traditional watermarking and fingerprinting techniques have been proposed, However, previous protocols have potential risk from trust third party （TTP） because all entities （including multi-buyers and multi-sellers） mentioned in protocol construct a star tupology like connection, in which the watermark certification authority （WCA） serves as the central point in the interaction and therefore its availability probably turns out to be the vital bottleneck of reliability and efficiency to the whole system. Secondly, WCA holds entire information about watermark used hy Buyers so that an innocent Buyer can he found as guilty if WCA collude with the Seller. In this paper, we propose a watermarking protocol to address the problems using cryptographic technologies in phase of watermark generation. The resuh is a TTP-independent and collusion-secure buyer-seller watermarking protocol.     

Improved Authenticated Multi-Key Agreement Protocol

Zhou et al give an attack on Ham＇s modified authenticated multi-key agreement protocol, and give a protocol that can prevent the unknown key-share attack. The paper points out that the protocol is vulnerable to a concatenation attack. This paper proposes an improved authenticated multi-key agreement protocol which shows how to make Harn＇s protocol more secure by modifying the signature and verification. And this protocol can escape the concatenation attack.     

L-Fuzzy拓扑空间中的T21/3分离性

在LF拓扑空间中定义T_(2~(1/3)),ST_(2~(1/3))和层T_(2~(1/3))分离性,讨论与其他分离性的关系,论证了它们是L-好的推广,并研究了它们的一些性质.     

一种快速高效二维时域有限元束传播法

提出并建立了一种新型的快速分析平面光波光路器件传输特性的2D时域有限元束传播法(FE-TD-BPM)模型.与常规时域差分格式的有限元束传播法相比,在时域实现了一维有限元(FEM)离散化处理,基于完全匹配层(PML)边界条件给出了全有限元离散化模型.为了验证算法的精度以及速度,模拟分析了直脊波导以及波导光栅,并且与已有文献的计算结果进行比较,结果表明,该算法无条件稳定、计算速度快,与常规时域差分格式的有限元束传播法相差在0.002%以内,并节省了约70%的机时.     

锌铝水滑石的香豆素-3-甲酸和9-蒽甲酸共插层

以层状锌铝水滑石为主体，乙二醇为分散介质，通过离子交换法，成功地将一对具有给体-受体性质的生色团香豆素-3-甲酸(3-CCA)与9-蒽甲酸(9-ACA)共插入到层状锌铝水滑石层间。采用XRD、IR、TG-DTA等测试技术对共插层产物进行了结构表征，采用UV-visible吸收光谱和荧光光谱研究了产物的光谱特性。结果表明，由于给体-受体进入层间，不仅客体与主体层板存在静电力和氢键相互作用，而且在限域空间内存在客体之间的相互作用，从而产生了给体-受体间的能量转移。     

一种用于模拟汉字认知过程的多层自组织神经网络

为了模拟汉语初学者的汉字认知过程,在Kohonen神经网络的基础上,改进了其网络结构和算法,并且将改进后的网络输出层根据Hebbian学习规则连接,构建了一个多Kohonen网络协同工作的汉字认知自组织神经网络模型.模拟研究结果表明,模型能够成功地学习到汉字的结构类型,且能有效识别出汉字的部件,在一定程度上模拟了汉字认知的部分过程,说明该模型用于汉字认知乃至汉语言习得的可行性.     

旧路加宽路面结构层参数变化的敏感性分析

旧路加宽改造后,由于沉降和变形的差异而可能造成路面结构层的层底脱空,从而使路面结构处于非常不利的受力状态.路面结构受力状态的变化受诸多因素的影响,其中最为值得关注的结构层参数的变化.运用三维有限元法分析了结构层参数变化对层底脱空状态路面结构受力影响的敏感性,提出了在旧路加宽加铺改造工程中可供借鉴的结构层参数取值.     

简单网络时间协议分析及实现

介绍了信息技术对时间同步技术的需求,分析了简单网络时间同步的工作原理,讨论了时间同步的客户端软件实现.软件测试的结果表明同步精度可达1～50 ms.