World Wide Web search engines process millions of queries per day from users all over the world. Efficient query evaluation is achieved through the use of an inverted index, where, for each word in the collection the index maintains a list of the documents in which the word occurs. Query processing may also require access to document specific statistics, such as document length; access to word statistics, such as the number of unique documents in which a word occurs; and collection specific statistics, such as the number of documents in the collection. The index maintains individual data structures for each these sources of information, and repeatedly accesses each to process a query. A by-product of a web search engine is a list of all queries entered into the engine: a query log. Analyses of query logs have shown repetition of query terms in the requests made to the search system. In this work we explore techniques that take advantage of the repetition of user queries to improve the accuracy or efficiency of text search. We introduce an index organisation scheme that favours those documents that are most frequently requested by users and show that, in combination with early termination heuristics, query processing time can be dramatically reduced without reducing the accuracy of the search results. We examine the stability of such an ordering and show that an index based on as little as 100,000 training queries can support at least 20 million requests. We show the correlation between frequently accessed documents and relevance, and attempt to exploit the demonstrated relationship to improve search effectiveness. Finally, we deconstruct the search process to show that query time redundancy can be exploited at various levels of the search process. We develop a model that illustrates the improvements that can be achieved in query processing time by caching different components of a search system. This model is then validated by simulation using a document collection and query log. Results on our test data show that a well-designed cache can reduce disk activity by more than 30%, with a cache that is one tenth the size of the collection.

To protect the environment and save human lives, the detection of various hazardous toxins of biological or chemical origin has been a major challenge to the researchers at Oregon State University. Living fish cells can indicate the presence of a wide range of toxins by reactions such as changing color and shape changes. A research team in Electrical and Computer Engineering Department is developing a hybrid detection device (Cytosensor) that combines biological reaction and digital technology. The functions of Cytosensor can be divided into three parts, which are real-time image acquisition, data processing and statistical data analysis. User-friendly Web-Based Distributed Applications (WBDA) for Cytosensor offer various utilities. WBDA allow the users to control and observe the local Cytosensor, search and retrieve data acquired by the sensor network, and process the acquired images remotely using only a web browser. Additionally, these applications minimize the user's exposure to dangerous chemicals or biological products. This thesis describes the design of a remote controller, system observer, remote processor, and search engine using JAVA applets, XML, Perl, MATLAB, and Peer-to-Peer models. Furthermore, the implementations of image segmentation technique in MATLAB and the Machine Vision Algorithm in JAVA for independent web-based processing are investigated. / Graduation date: 2003

After completing this tutorial you will be able to use multiple search terms and other advanced features in "Google." This flash tutorial requires a screen resolution of 1024 x 768 or higher.

In this thesis we study a problem that arises in answering boolean queries submitted to a search engine. Usually a search engine stores the set of IDs of documents containing each word in a pre-computed sorted order and to evaluate a query like "computer AND science" the search engine has to evaluate the union of the sets of documents containing the words "computer" and "science". More complex queries will result in more complex set expressions. In this thesis we consider the problem of evaluation of a set expression with union and intersection as operators and ordered sets as operands. We explore properties of comparison-based algorithms for the problem. A <i>proof of a set expression</i> is the set of comparisons that a comparison-based algorithm performs before it can determine the result of the expression. We discuss the properties of the proofs of set expressions and based on how complex the smallest proofs of a set expression <i>E</i> are, we define a measurement for determining how difficult it is for <i>E</i> to be computed. Then, we design an algorithm that is adaptive to the difficulty of the input expression and we show that the running time of the algorithm is roughly proportional to difficulty of the input expression, where the factor is roughly logarithmic in the number of the operands of the input expression.

Due to the information explosion on the Internet, effective information search techniques are required to retrieve the desired information from the Web. Based on much analysis on users' search intention and the variant forms of Web content, we find that both the query and the indexed web content are often associated with various context information, which can provide much essential information to indicate the ranking relevance in Web search. This dissertation seeks to develop new search algorithms and techniques by taking advantage of rich context information to improve search quality and consists of two major parts. In the first part, we study the context of the query in terms of various ranking objectives of different queries. In order to improve the ranking relevance, we propose to incorporate such query context information into the ranking model. Two general approaches will be introduced in the following of this dissertation. The first one proposes to incorporate query difference into ranking by introducing query-dependent loss functions, by optimizing which we can obtain better ranking model. Then, we investigate another approach which applies a divide-and-conquer framework for ranking specialization. The second part of this dissertation investigates how to extract the context of specific Web content and explore them to build more effective search system. This study is based on the new emerging social media content. Unlike traditional Web content, social media content is inherently associated with much new context information, including content semantics and quality, user reputation, and user interactions, all of which provide useful information for acquiring knowledge from social media. In this dissertation, we seek to develop algorithms and techniques for effective knowledge acquisition from collaborative social media environments by using the dynamic context information. We first propose a new general framework for searching social media content, which integrates both the content features and the user interactions. Then, a semi-supervised framework is proposed to explicitly compute content quality and user reputation, which are incorporated into the search framework to improve the search quality. Furthermore, this dissertation also investigates techniques for extracting the structured semantics of social media content as new context information, which is essential for content retrieval and organization.

Thesis (M.S.)--University of Florida, 2002. / Title from title page of source document. Includes vita. Includes bibliographical references.

Google Inc. struggles arduously on the digital battlefield in China’s Internet search engine market. In China, Baidu.com has been described as China’s Google for years and challenged Google’s expansion. This study provides an overview of the Internet service development in China, an illustration of the search engines’ profitability models, and an evaluation of Guge (Google China) and Baidu’s service designs. Overall, the research shows an attempt to understand the possible advantages and disadvantages when a multinational Internet service company enters China. Two notions emerge. First, standardization and adaptation may need to be nicely balanced for the subsidiary company in order to profit in China’s Internet market. Second, Google’s operation in China, Guge, stands strong on the service design end, especially in the area of “ease of use,” “informativeness,” and “fulfillment/reliability.” However, Guge’s major rival, Baidu, shows its advantage on a wider selection of online services. Therefore, in the long run, which company will win at the finishing line is still too early to tell / Google in China -- Google, Baidu and Guge -- Search engine's revenue model in China. / Department of Telecommunications

This exploratory research investigates the factors that might influence a specific group of users’ mental models of a Web search engine, Google, as measured in the dimension of completeness. A modified mental model completeness scale (MMCS) was developed based on Borgman’s, Dimitroff s, and Saxon’s models, encompassing the perception of (1) the nature of the Web search engine, (2) searching features of the Web search engine, and (3) the interaction between the searcher and the Web search engine. With this scale, a participant’s mental model completeness level was determined by how many components of the first two parts of the scale were described and which level of interaction between the participant and Google was revealed during the searches. The choice of the factors was based on the previous studies on individual differences among information seekers, including user’s search experience, cognitive style, learning style, technical aptitudes, training received, discipline, and gender. Sixteen Ph.D. students whose first language is English participated in the research. Individual semi-structured interviews were conducted to determine the students’ mental model completeness level (MMCL) as well as their search experience, training received, discipline and gender. Direct observation technique was employed to observe students’ actual interactions with Google. Standard tests were administered to determine the students’ cognitive styles, learning styles and technical aptitudes. / Cette recherche préliminaire examine les facteurs qui peuvent influencer les modèles mentaux d’un groupe spécifique d’utilisateurs d’un moteur de recherche sur le Web: Google, mesurés selon l’étendue de leur réussite.Une échelle de cette réussite en suivant un modèle mental a été constituée en adaptant les modèles présentés par Borgman, Dimitroff et Saxon, incluant la perception (1) de la nature du moteur de recherche sur le Web, (2) des caractéristiques de la recherche propres à ce moteur, (3) de l’interaction entre le chercheur et le moteur de recherche. A l’aide de cette échelle, le niveau de réussite par un sujet donné utilisant un modèle mental a été déterminé en fonction du nombre de composantes des deux premières parties de l’échelle décrites et du niveau d’interaction entre le sujet et le moteur Google, tel que révélé par ses recherches. Le choix des facteurs a été fondé sur des études précédentes portant sur les différences individuelles entre les chercheurs d’information, comprenant le degré d’expérience d’une telle recherche par l’utilisateur, son style cognitif, son style d’apprentissage, ses aptitudes techniques, la formation reçue, la discipline et le sexe. Seize étudiants en doctorat ayant l’anglais comme première langue ont participé à cette étude. Des entretiens individuels semi-dirigés ont permis de déterminer le niveau de réussite des étudiants suivant leur modèle mental, ainsi que leur expérience de la recherche, la formation reçue, la discipline et le sexe. Une observation technique directe a été utilisée pour observer l’interaction réelle des étudiants avec Google. Des tests standardisés ont été administrés pour déterminer le style cognitif des étudiants, leur style d’apprentissage et leurs aptitudes techniques. fr

Proefschrift Universiteit van Amsterdam. / Met lit.opg. en samenvatting in het Nederlands.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.