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基于属性相似性的Item-based协同过滤算法 被引量:21
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作者 彭玉 程小平 《计算机工程与应用》 CSCD 北大核心 2007年第14期144-147,共4页
通过分析传统Item-based协同过滤推荐中的稀疏性问题以及新项目的冷开始问题,提出了一个基于属性相似性的Item-based协同过滤算法。该算法利用项目属性的相似性来修正原始相似性计算,综合考虑项目属性和用户评价对推荐的影响,改进了传... 通过分析传统Item-based协同过滤推荐中的稀疏性问题以及新项目的冷开始问题,提出了一个基于属性相似性的Item-based协同过滤算法。该算法利用项目属性的相似性来修正原始相似性计算,综合考虑项目属性和用户评价对推荐的影响,改进了传统相似性度量方法在评价数据稀疏和新项目推荐中测量结果不够准确的问题。 展开更多
关键词 item—based协同过滤 项目属性 评价相似性 属性相似性
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PEV:一种新的用于Item-Based协同过滤算法的相似性度量方法 被引量:5
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作者 张忠平 郭献丽 《小型微型计算机系统》 CSCD 北大核心 2009年第4期716-720,共5页
在Item-Based协同过滤算法中,项目之间相似性的度量是整个算法的关键.通过分析传统的相似性度量方法在系统评分数据稀疏的情况下所存在的弊端,提出一种新的用于Item-Based协同过滤算法的相似性度量方法,该方法从邻近度、影响力、有用性... 在Item-Based协同过滤算法中,项目之间相似性的度量是整个算法的关键.通过分析传统的相似性度量方法在系统评分数据稀疏的情况下所存在的弊端,提出一种新的用于Item-Based协同过滤算法的相似性度量方法,该方法从邻近度、影响力、有用性三个方面综合考虑了用户评分对项目相似性的影响.实验结果表明,该方法能够有效地避免传统相似性度量方法所存在的问题,使得数据稀疏性对最终推荐结果的负面影响变小,在一定程度上提高系统的推荐精度. 展开更多
关键词 推荐系统 item—Based协同过滤 项目相似性 稀疏性
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一种优化的Item-based协同过滤推荐算法 被引量:25
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作者 汪静 印鉴 《小型微型计算机系统》 CSCD 北大核心 2010年第12期2337-2342,共6页
针对传统的Item-based协同过滤推荐算法在推荐系统应用中存在的不足,提出一种优化的Item-based协同过滤推荐算法.从项目相似性计算,项目近邻选取和预测评分计算三个方面对算法进行了优化,使计算结果更具有实际意义和准确性.实验结果表明... 针对传统的Item-based协同过滤推荐算法在推荐系统应用中存在的不足,提出一种优化的Item-based协同过滤推荐算法.从项目相似性计算,项目近邻选取和预测评分计算三个方面对算法进行了优化,使计算结果更具有实际意义和准确性.实验结果表明,提出的算法可解决传统方法中由于数据稀疏所导致的相似性度量不准确的问题,并显著地提高了算法的推荐精度. 展开更多
关键词 项目相似性 项目近邻选取 预测评分 item-based协同过滤 推荐系统
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基于组合加权评分的Item-based协同过滤算法 被引量:4
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作者 马丽 《现代图书情报技术》 CSSCI 北大核心 2008年第11期60-64,共5页
针对Item-based协同过滤算法中用户评分数据稀疏性严重影响推荐质量的问题,提出一种基于组合加权评分的Item-based协同过滤算法,以用户评分项并集作为用户相似性计算基础,并提出一种组合加权评分方法来对并集中的未评分项进行计算和填补... 针对Item-based协同过滤算法中用户评分数据稀疏性严重影响推荐质量的问题,提出一种基于组合加权评分的Item-based协同过滤算法,以用户评分项并集作为用户相似性计算基础,并提出一种组合加权评分方法来对并集中的未评分项进行计算和填补,从而降低了数据稀疏性。实验结果表明该算法能有效提高推荐质量。 展开更多
关键词 数字图书馆 电子商务 item—based协同过滤算法 组合加权评分
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一种改进的Item-based协同过滤推荐算法 被引量:17
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作者 彭玉 程小平 徐艺萍 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2007年第5期146-149,共4页
分析了协同过滤推荐系统中存在的用户多兴趣和项目多内容问题,提出了一种基于项的协同过滤改进算法,算法综合考虑了项目自身属性和用户评价的影响.试验表明该算法有效的解决了用户的多兴趣和项目的多内容问题,并且在用户评分数据比较稀... 分析了协同过滤推荐系统中存在的用户多兴趣和项目多内容问题,提出了一种基于项的协同过滤改进算法,算法综合考虑了项目自身属性和用户评价的影响.试验表明该算法有效的解决了用户的多兴趣和项目的多内容问题,并且在用户评分数据比较稀疏的情况下也能有较好的推荐精度. 展开更多
关键词 推荐系统 基于项的协同过滤 属性相似性
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众创空间创客团队的“ITEM”融合模式与循环迭代——基于青创迭代创空间案例研究 被引量:1
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作者 冯锋 曹阳 《华南理工大学学报(社会科学版)》 2019年第3期29-38,共10页
以青创迭代创空间两个典型创客团队为案例研究对象,从创客团队的角度,研究其兑现创意、实现创业的过程和内在机理,提出了众创空间"ITEM"融合与循环迭代模型。研究发现:第一,创客团队的创新创业包括创意、技术、企业家精神、... 以青创迭代创空间两个典型创客团队为案例研究对象,从创客团队的角度,研究其兑现创意、实现创业的过程和内在机理,提出了众创空间"ITEM"融合与循环迭代模型。研究发现:第一,创客团队的创新创业包括创意、技术、企业家精神、制造四个主环节且相互融合;第二,创客团队"ITEM"融合是一个循环迭代的过程。通过深入现实创客团队调研,总结出的融合模式和循环迭代模式对深入理论探讨和创客团队创新创业实践具有参考价值。 展开更多
关键词 创新 技术创新 众创空间 item”融合 循环迭代
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自适应用户的Item-based协同过滤推荐算法 被引量:9
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作者 汪从梅 王成良 徐玲 《计算机应用研究》 CSCD 北大核心 2013年第12期3606-3609,共4页
传统Item-based协同过滤算法计算两个条目间相似性时,将每个评分视为同等重要,忽略了共评用户(对两个条目共同评分的用户)与目标用户间的相似性对条目间相似性的影响。针对此问题,提出了一种自适应用户的Item-based协同过滤算法。该算... 传统Item-based协同过滤算法计算两个条目间相似性时,将每个评分视为同等重要,忽略了共评用户(对两个条目共同评分的用户)与目标用户间的相似性对条目间相似性的影响。针对此问题,提出了一种自适应用户的Item-based协同过滤算法。该算法将共评用户与目标用户的相似性作为共评用户评分重要性的权重,以实现针对不同的目标用户,为目标条目选择不同的、适合目标用户的最近邻居集,从而提高推荐准确性。实验结果表明,提出的算法可以显著提高推荐系统的推荐质量。 展开更多
关键词 推荐系统 协同过滤 item—based 自适应用户 条目相似性 信息过载
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ITEM ToolKit软件在电力系统可靠性分析中的应用
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作者 蒋纬纬 丁坚勇 《西北电力技术》 2002年第6期11-14,共4页
美国ITEM软件公司推出的ITEM ToolKit可靠性分析软件,功能强大,操作方便,在介绍其基本功能的基础上,阐述了如何将其应用于电力系统可靠性分析中,该软件可以满足电力系统多种可靠性分析的需求。
关键词 电力系统 可靠性 ToolKit软件 item公司
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ITEM软件在基于故障树诊断中的应用 被引量:1
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作者 金亮亮 姜斌 刘剑慰 《控制工程》 CSCD 2007年第S3期90-92,共3页
在复杂的故障树中,手工定量分析故障树和求取最小割集比较的困难。利用可靠性工程软件ITEM对故障树进行建造和分析,快速地求取出了故障树的顶事件的发生概率,最小割集数及其发生的概率。从结果中得到各个底事件的重要度,分析出各个底事... 在复杂的故障树中,手工定量分析故障树和求取最小割集比较的困难。利用可靠性工程软件ITEM对故障树进行建造和分析,快速地求取出了故障树的顶事件的发生概率,最小割集数及其发生的概率。从结果中得到各个底事件的重要度,分析出各个底事件在故障树中对顶事件发生贡献度大小和在故障树结构中的重要性,从而给出了系统设计的薄弱环节,为提高和保证系统的可靠性提供了有效的方法。并从给的最小割集量级上进行比较,为系统故障源搜索提供较好的测试步骤。 展开更多
关键词 item 故障树 故障诊断
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一种基于Web日志的Item-Based协同过滤算法改进
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作者 王春才 邢晖 吕东方 《软件导刊》 2015年第3期46-48,共3页
在目前众多的电子商务推荐方法中,协同过滤的研究和应用最为广泛。但由于其自身存在的一些诸如数据稀疏性与缺少个性化等问题,导致推荐的准确度与效率不高。而且User-Based协同过滤算法存在用户规模过大、不易寻找最近邻的问题。因此,... 在目前众多的电子商务推荐方法中,协同过滤的研究和应用最为广泛。但由于其自身存在的一些诸如数据稀疏性与缺少个性化等问题,导致推荐的准确度与效率不高。而且User-Based协同过滤算法存在用户规模过大、不易寻找最近邻的问题。因此,引入了Web日志挖掘方法,并利用Item-Based等相关技术,以提高推荐准确度。 展开更多
关键词 WEB日志挖掘 item-Based 协同过滤 电子商务
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Optimization approach of background value and initial item for improving prediction precision of GM(1,1) model 被引量:34
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作者 Yuhong Wang Qin Liu +2 位作者 Jianrong Tang Wenbin Cao Xiaozhong Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第1期77-82,共6页
A combination method of optimization of the back-ground value and optimization of the initial item is proposed. The sequences of the unbiased exponential distribution are simulated and predicted through the optimizati... A combination method of optimization of the back-ground value and optimization of the initial item is proposed. The sequences of the unbiased exponential distribution are simulated and predicted through the optimization of the background value in grey differential equations. The principle of the new information priority in the grey system theory and the rationality of the initial item in the original GM(1,1) model are ful y expressed through the improvement of the initial item in the proposed time response function. A numerical example is employed to il ustrate that the proposed method is able to simulate and predict sequences of raw data with the unbiased exponential distribution and has better simulation performance and prediction precision than the original GM(1,1) model relatively. 展开更多
关键词 background value initial item grey system theory grey prediction.
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The Application of Trapezoidal Fuzzy AHP on Evaluation Item Weight Calculation of Highway Network Programming Schemes 被引量:1
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作者 吴晓琼 邵世煌 蒲芳 《Journal of Donghua University(English Edition)》 EI CAS 2004年第6期98-103,共6页
The fuzzy theory is invited in this paper to calculate weights of evaluation items, which is a very important stage in highway network evaluation. Highway network evaluation is a composite of various attributes that l... The fuzzy theory is invited in this paper to calculate weights of evaluation items, which is a very important stage in highway network evaluation. Highway network evaluation is a composite of various attributes that lack of pertinency and comparability, and their commonality is that they are more or less tainted with uncertainty, with different daily decision making problems of diverse intensity, the results can be misleading if the fuzziness of human decision-making is not taken into account. So we introduce fuzzy theory into the measurement of evaluating weights to overcome the issue and Analytic Hierarchy Process in scheme ranking. It is testified to be a more reliable way through the case study of Yangtze River Delta highway network evaluation. 展开更多
关键词 HIGHWAY network trapezoidal fuzzy AHP WEIGHTS of EVALUATION items
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Analysis of an Inventory System for Items with Stochastic Demand and Time Dependent Three-Parameter Weibull Deterioration Function 被引量:1
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作者 Nwoba Pius Ophokenshi Chukwu Walford Ikechukwu Emmanuel Maliki Olaniyi Sadik 《Applied Mathematics》 2019年第9期728-742,共15页
In recent times, mathematical models have been developed to describe various scenarios obtainable in the management of inventories. These models usually have as objective the minimizing of inventory costs. In this res... In recent times, mathematical models have been developed to describe various scenarios obtainable in the management of inventories. These models usually have as objective the minimizing of inventory costs. In this research work we propose a mathematical model of an inventory system with time-dependent three-parameter Weibull deterioration and a stochastic type demand in the form of a negative exponential distribution. Explicit expressions for the optimal values of the decision variables are obtained. Numerical examples are provided to illustrate the theoretical development. 展开更多
关键词 INVENTORY Model Deteriorating items Weibull Distribution STOCHASTIC DEMAND MathCAD14
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Frequent item sets mining from high-dimensional dataset based on a novel binary particle swarm optimization 被引量:2
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作者 张中杰 黄健 卫莹 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第7期1700-1708,共9页
A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset(BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial partic... A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset(BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial particles was designed to ensure the reasonable initial fitness, and then, the dynamically dimensionality cutting of dataset was built to decrease the search space. Based on four high-dimensional datasets, BPSO-HD was compared with Apriori to test its reliability, and was compared with the ordinary BPSO and quantum swarm evolutionary(QSE) to prove its advantages. The experiments show that the results given by BPSO-HD is reliable and better than the results generated by BPSO and QSE. 展开更多
关键词 data mining frequent item sets particle swarm optimization
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Reducing Item Exposure in Computerized Adaptive Testing Systems Using Automatic Item Generation 被引量:1
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作者 Harutyun Terteryan 《Computer Technology and Application》 2014年第1期21-24,共4页
This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during e... This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during examinees prior testing. Disadvantage of the mentioned item calibration method is the item exposure; when test items become familiar to the examinees. To reduce the item exposure, automatic item generation method is used, where item models are being constructed based on already calibrated test items without losing already estimated item parameters. A technic of item model extraction method from the already calibrated and therefore exposed test items described, which can be used by the test item development specialists to integrate automatic item generation principles with the existing testing applications. 展开更多
关键词 item exposure calibration IRT item response theory) adaptive testing automatic item generation item model.
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An Ordering Policy for Deteriorating Items with Time-Dependent Quadratic Demand and Salvage Value under Permissible Delay in Payment 被引量:1
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作者 Trailokyanath Singh Madan Mohan Muduly +2 位作者 Chittaranjan Mallick Rahul Kumar Gupta Hadibandhu Pattanayak 《American Journal of Operations Research》 2019年第5期201-218,共18页
The article deals with an economic order quantity (EOQ) inventory model for deteriorating items in which the supplier provides the purchaser a permissible delay in payment. This is so when deterioration of units in th... The article deals with an economic order quantity (EOQ) inventory model for deteriorating items in which the supplier provides the purchaser a permissible delay in payment. This is so when deterioration of units in the inventory is subject to constant deterioration rate, demand rate is quadratic function of time and salvage value is associated with the deteriorated units. Shortages in the system are not allowed to occur. A mathematical formulation is developed when the supplier offers a permissible delay period to the customers under two circumstances: 1) when delay period is less than the cycle of time;and 2) when delay period is greater than the cycle of time. The method is suitable for the items like state-of-the-art aircrafts, super computers, laptops, android mobiles, seasonal items and machines and their spare parts. A solution procedure algorithm is given for finding the optimal order quantity which minimizes the total cost of an inventory system. The article includes numerical examples to support the effectiveness of the developed model. Finally, sensitivity analysis on some parameters on optimal solution is provided. 展开更多
关键词 Constant Deterioration RATE Deteriorating items Economic Order Quantity Permissible Delay in PAYMENT SALVAGE Value TIME-DEPENDENT QUADRATIC DEMAND RATE
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Financial reporting of cash flow: Arbitrary items and management preferences 被引量:1
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作者 Lau Chee Kwong 《Journal of Modern Accounting and Auditing》 2010年第4期1-14,25,共15页
The international financial reporting standard for cash flow statement (IAS 7) provides options for the classification of certain cash flow items (arbitrary items). Therefore, business firms may classify the arbit... The international financial reporting standard for cash flow statement (IAS 7) provides options for the classification of certain cash flow items (arbitrary items). Therefore, business firms may classify the arbitrary items using the option that would maximize their own interest. This reduces the comparability of financial statements amongst business firms. This study aims to investigate the factors explaining management preferences in the selection of financial reporting practices on the arbitrary cash flow items. It concludes that managers tend to magnify the CFO reported in order to maximize the shareholders' wealth, which in turn would maximize their compensation. Managers of business firms with a relatively smaller size of CFO tend to classify interest paid and dividends paid as non-CFO in order to magnify their CFO. They also tend to classify interest received as CFO in order to inflate their relatively smaller size of CFO up to expectation. Similarly, managers of business firms with a relative larger size of dividends paid would classify the dividends paid outside CFO. 展开更多
关键词 cash flow reporting arbitrary items management preference
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Study on C-E Translation of Lexical Items with Chinese Characteristics in the Report on the 19th National Congress of the CPC
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作者 何晴 侯先绒 《海外英语》 2018年第13期150-151,155,共3页
The 19th National Congress of the Communist Party of China is a meeting of great importance held during the decisivestage of building a moderately prosperous society in all respects.As a window to know about the lates... The 19th National Congress of the Communist Party of China is a meeting of great importance held during the decisivestage of building a moderately prosperous society in all respects.As a window to know about the latest changes of China,it is au-thoritative and of much value to study.As time goes by,there emerge more lexical items with Chinese characteristics.This articlestudies Chinese-English translation skills of lexical items with Chinese Characteristics in the Report on the 19th National Congressof the CPC.First,it classifies these lexical items into several kinds including those related with economy,politics,culture,peo-ple’s wellbeing and other lexical items,and then studies them respectively. 展开更多
关键词 the Reporton the 19th NATIONAL CONGRESS of the CPC LEXICAL items with CHINESE Characteristics Chinese-English TRANSLATION skills
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STROBE Statement—Checklist of items that should be included in reports of case-control studies STROBE声明:病例对照研究报告写作清单①对文题、摘要、引言、方法的写作要求 被引量:1
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《中国组织工程研究》 CAS CSCD 2012年第20期3800-3800,共1页
Ⅰ.Title and abstract标题和摘要1(a)Indicate the study's design with acommonly used term in the title or the abstract
关键词 摘要 写作要求 文题 Checklist of items that should be included in reports of case-control studies STROBE STROBE Statement 声明 病例对照 清单 case
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Effects of Imperfect Quality and Defective Items on Economic Production Lot Size
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作者 Raafat N Ibrahim Paul Lochert 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期247-,共1页
The classical EPQ model has been used for a long ti me and is widely accepted and implemented. Nevertheless, the analysis for finding an economic lot size has based on a number of unrealistic assumptions. A common unr... The classical EPQ model has been used for a long ti me and is widely accepted and implemented. Nevertheless, the analysis for finding an economic lot size has based on a number of unrealistic assumptions. A common unrealistic assumption in using EPQ is that all units produced are of good quali ty. The classical EPQ model shows that the optimal lot size will generate minimum ma nufacturing cost, thus producing minimum setup cost and inventory cost. However, this is only true if all products manufactured in the process are assumed to be of good quality (i.e. all products are within the specification limits). In rea lity this is not the case, therefore, it is necessary to consider the cost of im perfect quality items, because this cost can influence the economic lot size. Ma ny studies and recent papers have indicated that there is a significant relation ship between economic production lot size and process/product quality. However, their models included either the imperfect quality items (not necessarily de fective) which are to be sold at a discounted price or defective items which can be reworked or rejected. The aim of this paper is to provide a framework to integrate three different sit uations (discounted pricing/rework/reject) into a single model. 100% inspection is performed in order to distinguish the amount of good quality items, imper fect quality items and defective items in each lot. In this paper, a mathematica l model is developed, and a numerical example is presented to illustrate the sol ution procedures. It is found that the economic production lot size tends to inc rease as the average percentage of imperfect quality items and defectives (rejec ted items) increases. 展开更多
关键词 EPQ lot size imperfect/defective items
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