情境感知的移动阅读个性化推荐算法研究

针对移动环境下资源的个性化推荐问题,提出一种结合情境和协同过滤的移动阅读推荐算法。该算法汇聚了两阶段的情境感知思想,首先使用朴素贝叶斯方法推算用户某情境下偏好度最高的资源类别,然后对该类别下的资源,通过情境相似度的计算,过滤出仅当前情境或者与当前情境最相似的情境的"用户-资源"二维评分模型,再运用传统的基于用户的协同过滤算法产生推荐列表。抓取新浪博文进行实验测试,结果表明相同条件下所提出算法的平均绝对偏差值比其他相关算法要低,具有更高的推荐质量。     

特征聚类的混合协同过滤算法研究

针对推荐系统的准确性提出了一种优化算法,该算法首先利用用户的特征进行聚类,然后在聚类之后的各个聚簇中运用混合协同过滤框架为每个聚簇训练一个模型;同时在运用混合协同过滤时,针对传统的基于用户的协同过滤推荐算法在计算用户相似度方面进行了改进.实验表明,提出的优化算法显著提高了预测的准确性,从而提高了推荐结果的质量.     

基于用户画像与协同过滤的大规模定制智能推荐算法研究

大规模定制模式的兴起与发展有效缓解了用户对差异化、个性化产品的需求与追求定制化产品成本高昂之间的矛盾。为更高效地辅助用户在大规模定制过程中做出满意的产品定制决策,对传统面向大规模定制的推荐算法进行相应改进,并结合大规模定制的特征,提出基于用户画像的定制方案推荐算法。选用基于物品的协同过滤算法作为基础推荐算法,引入大数据工具——用户画像模型对初始推荐结果进行二次过滤,以改善传统协同过滤推荐算法易忽视用户自身兴趣偏好特征的问题,提高用户定制体验与推荐精准性。给出手机产品定制案例,对产生最终推荐结果的整个过程进行模拟与分析,验证该推荐算法的有效性和可行性。     

面向燃气具的用户个性化推荐模型

基于协同过滤推荐技术,构建了面向燃气具的用户个性化推荐模型。首先,根据用户注册信息与评分信息获取目标用户的相似用户以及偏好产品集;然后,根据目标用户的购买偏好确定产品的评价指标,并对偏好产品集进行评价。最后,通过算例分析证明了提出模型对燃气具个性化推荐的可行性和推荐结果的有效性。     

基于用户行为聚类的个性化推荐算法

将介绍一种基于用户行为聚类的协同过滤推荐算法苛刻算法首先采用web日志和数据库记录的方法,将用户的行为记录下来,并将这些隐性的用户行为转化为显性的用户对项目评价;然后采用改进后的相似度计算方法计算用户之间的相似度;接着对用户进行聚类,将用户按照他们的行为自动地划分为若干个用户聚类簇;最后根据用户对最近邻居的评分来预测其对目标项目的评分,进而产生推荐。     

基于GPS轨迹挖掘的兴趣地点个性化推荐方法

随着全球定位系统(GPS)等定位设备的普及,用户可方便地记录其GPS轨迹,这使得自动从用户的GPS轨迹中发现兴趣地点(POI)(如餐厅、商场、景点)并在用户之间进行推荐成为可能。因此,本文提出了一种基于GPS轨迹挖掘的兴趣地点个性化推荐方法。该方法与现有主流的兴趣地点推荐平台具有以下不同:首先,现有平台假设兴趣地点是事先已知的,而该方法通过一个层次化聚类算法从用户GPS轨迹中自动挖掘兴趣地点。其次,现有平台的推荐模式为平台向用户推荐,因此仅考虑了用户的偏好,忽略了用户之间的社交关联对推荐效果的影响。针对此问题,该方法基于用户交叠访问行为计算用户之间的社交信任度,基于用户访问行为的相似性计算其对兴趣地点偏好的相似度,在此基础上提出了一种能够融合用户信任度和相似度的评分算法。文本基于真实GPS轨迹数据对提出的方法进行了评测,实验结果表明,本文所提方法的综合推荐性能明显优于简单的基于访问数量的推荐方法、仅基于用户信任度的推荐方法及仅基于偏好相似度的推荐方法。     

利用序列模型实现基于影片简介的相似影片推荐

相似性推荐是一种根据影片特征进行相似影片匹配的算法,不同于协同过滤推荐算法需要使用大量的用户行为数据,相似性推荐算法致力于影片本身的特征信息.本文涉及实验旨在实现一种能够应用于缺少用户行为数据场景下的影片推荐算法.文章基于序列模型和相似性计算方法,使用影片简介作为影片推荐的主要素材,搭建了一套在缺少用户订购历史数据的应...     

基于综合信任的奇异值分解推荐算法研究

针对传统矩阵分解推荐算法中数据稀疏、冷启动和用户信任矩阵数据稀疏等问题,本文提出了一种改进的基于路径的信任计算模型,利用用户-用户之间的直接信任关系和受信任者对用户信任关系的影响,计算用户-用户之间存在的间接信任关系,从而填充用户-用户信任矩阵。在此基础上,将用户之间的信任关系与奇异值分解(SVD)模型相结合,提出了一种融合综合信任的奇异值分解算法,即CT-SVD算法。该推荐算法结合用户评分矩阵和信任关系矩阵,对传统的奇异值分解推荐算法进行优化,提高了推荐系统评分预测的准确性。在FilmTrust和Ciao数据集上的实验结果表明,该算法能够有效地缓解推荐系统的数据稀疏性和冷启动问题。     

基于协同过滤的大规模定制个性化推荐方法

为了对用户的产品定制决策进行动态辅助和引导,让用户在大规模定制系统中的产品配置过程变得更简单、方便,在产品定制环节引入了协同过滤推荐算法的思想,并结合大规模定制的特点对推荐算法进行适当改进后提出了一种新的面向大规模定制的个性化推荐算法。给出一个手机定制的实例,对算法产生推荐结果的具体过程进行了模拟与分析。仿真实验产生的可行推荐方案表明,该算法对于解决大规模定制模式下的个性化推荐问题是可行有效的。     

注入主流价值导向的电影个性化推荐研究

互联网促进了文化产业飞速发展,电影个性化推荐作为电影搜索的补充,取得了较好的效果。个性化推荐在提高用户体验的同时,注入主流价值导向有助于网络环境向更健康的方向发展。一方面可以通过用户画像技术获取用户的电影内容偏好,并结合协同过滤算法为用户推荐可能感兴趣的电影;同时还应尝试从数据中分析用户的情绪与价值观,在推荐的召回环节和排序环节,有针对性地引入具有正向引导作用的电影内容。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.