关于加强计算机网络安全的几点思考

随着计算机网络的不断发展,全球信息化已成为人类发展的大趋势。但由于计算机网络具有联结形式多样性、终端分布不均匀性和网络的开放性、互连性等特征,致使网络易受黑客、怪客、恶意软件和其他不轨的攻击,所以网上信息的安全和保密是一个至关重要的问题。     

异质社交网络中多通道特征融合的好友推荐模型

合理有效的好友推荐算法对于社交网络的发展和扩张有重大的意义。然而随着社交网络的复杂化和异质化,传统推荐系统中协同过滤推荐方法不能满足需求。针对异质社交网络中存在着大量的内容相关信息这一特点,根据好友推荐的需求,提出了多通道特征融合的好友推荐模型。该模型对用户相关的多维特征进行挖掘与利用,包括显性特征(如用户profile,用户tag,社交关系等)和隐性特征(如用户重要度,挖掘用户标注发现其领域兴趣等),并进一步将这些内容相关的多特征融合到协同排序算法中进行学习训练。实验结果表明,随着多个内容特征的逐步融合,算法的MAP值稳步提高,最终相对未融合的协同排序方法提高了12%,并在一定程度上的解决了冷启动问题,提高了好友推荐的多样性。     

我国页岩气产业发展分析

页岩气作为天然气的替代品为缓解能源紧张起到了积极的推动作用,越来越引起了世界各国的重视。本文从全球视角统筹考虑,通过对美国、欧洲页岩气的发展进程、技术水平、政策措施等方面的分析,结合国内页岩气储量、分布、成藏等资源状况,对我国页岩气产业发展当前存在的主要问题进行了详细分析,提出了做好页岩气地质调查基础工作、加快页岩气技术创新、完善页岩气产业政策、设定合理价格、注重开发与环保协调、借鉴国外先进经验迅速发展我国页岩气产业的一系列政策建议。     

Optimisation and performance assessment of a digital signal-processing method for jitter measurement in PDH/SDH-based digital telecommunication networks

The paper deals with jitter measurement in telecommunication networks based on plesiochronous (PDH) or synchronous (SDH) digital hierarchies. The attention is mostly focused on PDH/SDH analysers compliant to the ITU-T recommendations, the accuracy of which seems to be unsatisfying for both designers and manufacturers. Trying to give an answer to this problem, a digital signal-processing method was already proposed by the author. It succeeded in improving jitter measurement accuracy by avoiding the use of timing recovery circuitry, always needed, on the contrary, in the aforementioned analysers.The method is here optimised with the aim both of automating jitter performance test of network elements that operate at the PDH bit rate of 140 Mbit/s and the SDH bit rate of 155 Mbit/s, and further enhancing the accuracy on jitter estimates. In particular, an innovative procedure for automatically recovering the binary information conveyed by the jittered signal under analysis is introduced, and a proper strategy for carrying out instantaneous jitter measurements at uniform time intervals is developed.After a brief outline of the old version of the method, the proposed enhancements are described in detail. Then, the performance of the optimised method is assessed through many laboratory tests on emulated signals, the results of which are given and discussed. At the end, the outcomes of real automatic tests, conducted on PDH/SDH-based equipment produced by Marconi Sud S.p.A., are also presented.     

Using Information Retrieval techniques for supporting data mining

The classic two-stepped approach of the Apriori algorithm and its descendants, which consisted of finding all large itemsets and then using these itemsets to generate all association rules has worked well for certain categories of data. Nevertheless for many other data types this approach shows highly degraded performance and proves rather inefficient.

We argue that we need to search all the search space of candidate itemsets but rather let the database unveil its secrets as the customers use it. We propose a system that does not merely scan all possible combinations of the itemsets, but rather acts like a search engine specifically implemented for making recommendations to the customers using techniques borrowed from Information Retrieval.     

超高层建筑屋顶直升飞机停机坪设置探讨及建议

为适应城市对国防、治安、反恐、消防、金融、通信、旅游等的需求,许多超高层建筑在屋顶设置了直升飞机停机坪,但现行的消防设计规范对超高层建筑屋顶设置直升机停机坪未做强制的规定,各方意见不一。笔者结合实践工作经验,试图以建筑高度为界限对超高层建筑屋顶直升飞机停机坪进行探讨并提出一些直升飞机停机坪设置的建议。     

我国生态保护和建设若干战略问题研究

为探索在生态文明建设理念指导下,如何总体上把握生态保护和建设的发展战略,采取多学科、宽领域、全方位、深层次、开放式的战略研究方法进行了深入研究分析,提出了我国生态保护和建设的基本思路、基本原则、战略目标、战略布局、主要任务、战略重点以及政策建议,以期对我国生态保护和建设起到推动作用。     

“十一五”期间我国能源市场供需前景研究

本文深入分析了“十一五”期间我国能源市场发展的环境、面临的问题与挑战,对“十一五”期间我国能源供需总量变化趋势做出了预测,最后提出了发展能源市场的政策建议。     

基于用户行为的网站推荐系统模型

网上营销的难点是如何寻找潜在客户。识别用户行为是一个复杂的过程,建议采用二维模型来寻找相关的项目,然后推荐给用户。但太多不相干的建议转化为用户信息过载问题。本研究的目的是在每个维度中找出已被用户搜索的项目／对象,最受好评的每个维度中的项目可给予建议。要做到这一点,我们采用张量,它可以有效地模拟多维Web日志中的用户搜索数据,然后确定在每一个搜索维度上的用户模型。所有的评估均基于真实数据集,这清晰地显示出比其他广泛使用的向量和矩阵方法的有效性。     

重庆市保障性住房影响因素分析及政策建议

重庆市被国务院批准为城乡统筹综合改革试验区,保障性住房发展正处在一个有利的时机,同时也面临着发展的压力和挑战.分析了重庆市保障性住房的市场和政策环境,借鉴发达国家住房保障模式,从城市区域范围的角度,对健全住房保障体系所需做出的基础性和支撑性工作提出建议.