Using query expansion in graph-based approach for query-focused multi-document summarization

This paper presents a novel query expansion method, which is combined in the graph-based algorithm for query-focused multi-document summarization, so as to resolve the problem of information limit in the original query. Our approach makes use of both the sentence-to-sentence relations and the sentence-to-word relations to select the query biased informative words from the document set and use them as query expansions to improve the sentence ranking result. Compared to previous query expansion approaches, our approach can capture more relevant information with less noise. We performed experiments on the data of document understanding conference (DUC) 2005 and DUC 2006, and the evaluation results show that the proposed query expansion method can significantly improve the system performance and make our system comparable to the state-of-the-art systems.     

拟合用户偏好的个性化搜索

文章从用户偏好的角度对个性化搜索进行了优化研究,提出了基于语义关联树的查询扩展算法以及基于该算法的拟合用户偏好的个性化搜索系统架构。语义关联树可以灵活有效地控制查询扩展模型,在此之上的拟合用户偏好的个性化搜索系统具有用户偏好自学习能力。实验证明,该方法能有效提高文本检索的准确率。     

A new robust relevance model in the language model framework

In this paper, a new robust relevance model is proposed that can be applied to both pseudo and true relevance feedback in the language-modeling framework for document retrieval. There are at least three main differences between our new relevance model and other relevance models. The proposed model brings back the original query into the relevance model by treating it as a short, special document, in addition to a number of top-ranked documents returned from the first round retrieval for pseudo feedback, or a number of relevant documents for true relevance feedback. Second, instead of using a uniform prior as in the original relevance model proposed by Lavrenko and Croft, documents are assigned with different priors according to their lengths (in terms) and ranks in the first round retrieval. Third, the probability of a term in the relevance model is further adjusted by its probability in a background language model. In both pseudo and true relevance cases, we have compared the performance of our model to that of the two baselines: the original relevance model and a linear combination model. Our experimental results show that the proposed new model outperforms both of the two baselines in terms of mean average precision.     

用流体静力称衡法测定液体的膨胀系数

:探讨用流体静力称衡法测定液体膨胀系数的实验方法     

中国新时期儿童文学的深层拓展

新时期儿童文学以其开放性、创造性和丰富性 ,将中国儿童文学推入了一个全新的发展阶段。其深层拓展的表现有三 :一是突破了“教育工具论”的束缚 ,确认儿童文学具有多元的价值功能和美学目的 ,提升作家的使命意识与人文关怀 ;二是摆脱了“成人中心论”的羁縻 ,确认儿童文学必须以切合少年儿童的精神世界与思维特征为基准的主体性原则 ,重建人的意识 ,塑造未来民族性格 ;三是校正了儿童文学标准单一性与创作现象丰富性之间的矛盾错位 ,确认以少年儿童年龄特征与接受心理的差异性来建构多层次的儿童文学分类 ,以推进儿童文学创作的发展繁荣     

中国经济稳步进入新一轮景气状态

本文讨论了目前中国经济通货紧缩的国内外经济主导力量及其近期显著的演化趋势。在此基础上,我们对中国宏观经济包括经济增长,通货膨胀以及国际收支等变量的近期演变进行了分析,并给出了今明两年的相关预测结果。     

基于CA的城市扩展动态模拟与预测

城市扩展动态过程的模拟与预测可以为区域发展、城市规划和管理等提供决策依据 .传统的各种城市模型不能完整地表示城市动态过程的时空信息和时空关系 ,通常将空间抽象为均质平原或简单功能区 ,将时间作为一个变量纳入方程 ,缺乏对城市动态系统的直接模拟 .细胞自动机 (CellularAutomata)是一种“自下而上”的动态模拟建模框架 ,具有模拟复杂系统时空演化过程的能力 .本文将标准CA模型的四元组进行了扩展以满足GIS环境下的城市扩展动态模拟的要求 ,建立了土地持续利用动态模拟模型 .运用此模型对包头市城市扩展进行了比较成功的模拟和对未来 1 5年城市发展趋势进行了预测 .     

高校扩招必须保证教学质量

高等学校招生数量持续增加,教育投资,教师队伍、教学设施学生质量、教学管理等新问题的出现,要求学校在扩大招生的同时必须保证教学质量,本语文通过对高校扩如效应的分析,按照建立了“宽进严出”的教育质量保证体系的思路,提出高校必须走内涵发展道路,在扩大招生的同时如何确保教学质量。     

Schooling as a positional good: the Brazilian metropolitan regions in recent decades

In this article, I aim to determine whether, in view of the trend of educational expansion in recent decades in Brazil, the role played by schooling in the labor market of Brazilian major metropolitan regions has changed, becoming positional rather than absolute. To this end, I analyze the influence of schooling on people’s income and occupational status. Based on data from the National Household Sample Survey (PNAD-IBGE) for years 1995, 2005 and 2015, I compare ordinary least squares models that use absolute and positional measures of schooling. The results show that the explanatory power is greater for positional measures than for absolute ones, and that this advantage has increased over recent decades. As a result, it is argued that although educational expansion possibly makes the chances of access to a certain absolute schooling level less unequal, it also ends up undermining the opportunity structure related to it.