基于Web挖掘的关联推荐算法研究

对用户需求的分析中使用Web挖掘,其中Web个性化的实现使用的是关联规则,这一规则能够为用户提供个性化服务,并且成为Web技术的研究热点。本文以网络教学系统为案例,来对Web挖掘的关联推荐算法进行探讨。内容主要涉及到Web数据挖掘技术、关联推荐算法的思路、算法分析。     

基于关联规则的Web日志挖掘算法研究

关联规则挖掘是数据挖掘研究领域中的一个重要的方法,旨在挖掘事务数据库中有趣的模式。阐述了Web日志挖掘和关联规则的基本内容,分析了经典Apriori算法的不足之处,提出了改进的算法。另外,利用论坛Web日志数据进行了对比实验,实验结果表明改进后的算法性能有较大提高。将改进后的算法应用于网络论坛的日志挖掘,找出用户的个性化访问模式,从而提高论坛的服务质量。     

基于Web使用数据挖掘的个性化推荐系统设计

Web使用挖掘是实现个性化推荐系统的有效途径。通过对网站日志数据进行挖掘发现频繁访问模式,再结合活动用户的访问页面序列来实现个性化的在线推荐。本文从体系架构及功能模块两个方面进行分析,提出了基于Web使用数据挖掘的个性化推荐系统架构。它包括三个方面:数据预处理、频繁访问路径挖掘及在线推荐。     

基于数据挖掘技术的图书馆个性化快速推荐算法研究

随着高校图书管理系统建设的不断发展,广大师生的图书借阅活动产生了大量的浏览数据。为了对以上借阅信息进行数据挖掘以便为读者提供更高水平的服务,提出一种基于数据挖掘技术的图书馆个性化快速推荐算法。首先对数据挖掘的主要方法和组织结构进行了介绍;然后对经典关联规则挖掘算法中的Apriori算法进行改进,提高了关联规则的运算效率;最后采用改进的Apriori算法对图书借阅历史数据进行关联分析,从而对读者做出个性化的推荐。实验结果表明,提出的图书馆个性化快速推荐算法具有较高的准确度和运行效率。     

改进的Apriori算法在网络购物推荐中的应用

介绍了Apriori算法的基本理论,针对该算法没有考虑到每项权值对挖掘结构产生影响的缺点,并结合在线购物网站的实际情况提出了一种改进的加权Apriori算法。实验结果表明,该算法在应用于个性化推荐中能够突出权值对挖掘结果的影响,推荐准确率得到一定的提高。     

基于Apriori数据挖掘算法的信息推荐图书管理系统设计

传统应用于图书管理系统的Apriori算法因数据库扫描次数过多,以及候选项集数量过大导致系统运行缓慢,为解决此问题,设计基于改进Apriori数据挖掘算法的信息推荐图书管理系统。系统结合C/S架构与B/S架构,分别向图书馆工作人员和借阅者开放图书信息。系统功能模块中数据预处理子模块从读者借阅数据库中提取借阅者以及图书相关信息数据,对数据进行清洗、转换以及集成处理后,关联规则挖掘子模块利用改进Apriori算法依据处理后的数据,挖掘出支持度大于最小支持度阈值以及置信度大于最小置信度阈值的强关联规则,生成关联规则数据库。个性化信息推荐子模块依据关联规则数据库中的借阅者同借阅者所选图书进行关联匹配,向借阅者推送与所读图书相关联图书信息,实现图书信息的个性化推荐。实验结果表明,该系统可有效推荐图书关联信息,且在50个客户端同时运行的情况下CPU占有率仅为6.58%,运行性能佳。     

关联规则在移动电子商务推荐系统中的应用

以数据挖掘中的关联规则为基础,深入研究了个性化推荐系统的架构和推荐系统模型。针对传统关联规则挖掘算法在解决移动电子商务环境个性化推荐问题时反复扫描数据库,频繁项挖掘效率低,关联规则挖掘准确率低以及规则大量冗余等不足,采用基于事务矩阵和兴趣度的关联规则挖掘算法构建个性化的推荐系统模型,提升了个性化推荐质量。     

基于关联规则的Web挖掘技术研究

关联规则是Web挖掘中一个重要的研究领域。为了挖掘出隐藏在数据间的相互关系,将关联规则的概念引入到Web挖掘系统中,把用户的访问路径以关联规则的形式表现出来。基于Apriori算法的思想,给出了适合Web挖掘用户访问的新Apriori算法规则及其模式,最后将结果在一些较简单的网页上进行了验证,取得了较好的应用效果。     

E-Learning系统的个性化推荐方法研究

以E-Learning系统建设为背景,通过采用文献查找、调查研究等方法探讨个性化推荐理论的内涵,并结合当前建设中的E-Learning系统,分析了目前常用的个性化推荐策略,并进行介绍比较和分析以后,总结经验,以应用于E-Learning系统的建设。提出适合于E-learning系统建设的个性化推荐策略:采用关联规则推荐策略和协同过滤技术,基于WEB技术建立一个虚拟学习系统,利用推荐算法,结合用户需求,将学习的资源、学习活动和学习策略进行整合,向用户推荐完整的满足用户需求的E-Learning学习方案。     

基于关联规则的网络行为分析

网络用户访问网站的过程中,产生了大量的用户浏览网页的相关记录,隐含着用户在上网过程中的行为习惯。但其中潜在的用户信息难以发现。因此,急需有效的方法提取这些数据中的信息,数据挖掘应用而生。其中,关联规则技术是应用广泛的技术之一。文中利用Apriori算法对Web结构数据进行关联规则挖掘,所得到的规则反映出页面之间的链接关系。分析挖掘结果可得到用户访问的行为规律,为相关网站的安全性和优化改进提供有效的决策依据。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.