Character N-Gram Tokenization for European Language Text Retrieval

The Cross-Language Evaluation Forum has encouraged research in text retrieval methods for numerous European languages and has developed durable test suites that allow language-specific techniques to be investigated and compared. The labor associated with crafting a retrieval system that takes advantage of sophisticated linguistic methods is daunting. We examine whether language-neutral methods can achieve accuracy comparable to language-specific methods with less concomitant software complexity. Using the CLEF 2002 test set we demonstrate empirically how overlapping character n-gram tokenization can provide retrieval accuracy that rivals the best current language-specific approaches for European languages. We show that n = 4 is a good choice for those languages, and document the increased storage and time requirements of the technique. We report on the benefits of and challenges posed by n-grams, and explain peculiarities attendant to bilingual retrieval. Our findings demonstrate clearly that accuracy using n-gram indexing rivals or exceeds accuracy using unnormalized words, for both monolingual and bilingual retrieval.     

Historical case study: A research strategy for diachronic analysis

History and case study are two diachronic research strategies commonly used to study political discourse as it relates to public libraries. Though suitable for some studies, these strategies are inexhaustive. A new, blended research strategy is therefore needed to accomplish what history and case study alone cannot. This hybrid strategy, historical case study, must analyze cases from the distant past to the present, using eclectic data sources, in order to produce both idiographic and nomothetic knowledge. To develop historical case study, the universal components of diachronic analysis are first identified. A general research design for historical case study is then introduced. Finally, historical case study is tested in an actual research project. Findings from this project reveal that historical case study is a successful diachronic research strategy. Historical case study is a new and valuable research design suitable for addressing questions related to change, continuity, development, and evolution.     

Persistent Misperceptions: Americans’ Misplaced Confidence in Privacy Policies, 2003–2015

This paper examines the persistence of Americans’ misunderstanding of the function of privacy policies. We also identify groups that have misplaced confidence in the privacy policy label and address whether the groups’ patterns of misperception have changed over time. The findings add a new dimension to the argument that the usefulness of privacy policies needs to be reassessed. As a remedy, we call for media literacy programs to address structural features of media systems that lead to broadly held misperceptions such as the one examined here.     

让我们更多地认识城市与城市研究(二)

本文是美国圣地亚哥大学教授詹姆斯·A·克莱普2008年4月在北京城市学院的演讲,演讲共三场。为便于读者全面地理解克莱普教授的演讲内容,全部演讲内容被编译成一篇。本文是根据演讲记录稿整理后,经克莱普教授本人审定英文稿编译。