Browsing by Subject "World Wide Web"
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Item Open Access Advantage of using Web 2.0 applications in class(ACM, 2010) Aydinol, Ayşe Begüm; Gültekin, ÖzgürIn this study the advantage of using Web 2.0 applications in terms of increasing student attention and enthusiasm will be emphasized by presenting the example of community service activities which were supported by the blog usage. Copyright 2010 ACM.Item Open Access Architecture of a grid-enabled Web search engine(Elsevier Ltd, 2007) Cambazoglu, B. B.; Karaca, E.; Kucukyilmaz T.; Turk, A.; Aykanat, CevdetSearch Engine for South-East Europe (SE4SEE) is a socio-cultural search engine running on the grid infrastructure. It offers a personalized, on-demand, country-specific, category-based Web search facility. The main goal of SE4SEE is to attack the page freshness problem by performing the search on the original pages residing on the Web, rather than on the previously fetched copies as done in the traditional search engines. SE4SEE also aims to obtain high download rates in Web crawling by making use of the geographically distributed nature of the grid. In this work, we present the architectural design issues and implementation details of this search engine. We conduct various experiments to illustrate performance results obtained on a grid infrastructure and justify the use of the search strategy employed in SE4SEE. © 2006 Elsevier Ltd. All rights reserved.Item Open Access Automated web services composition with the event calculus(Springer, 2007-10) Aydın, Onur; Kesim-Çiçekli, Nihan; Çiçekli, İlyasAs the web services proliferate and complicate it is becoming an overwhelming job to manually prepare the web service compositions which describe the communication and integration between web services. This paper analyzes the usage of the Event Calculus, which is one of the logical action-effect definition languages, for the automated preparation and execution of web service compositions. In this context, abductive planning capabilities of the Event Calculus are utilized. It is shown that composite process definitions in OWL-S can be translated into Event Calculus axioms so that planning with generic process definitions is possible within this framework. © 2008 Springer-Verlag Berlin Heidelberg.Item Open Access An automatic approach to construct domain-specific web portals(ACM, 2007-11) Altıngövde, İsmail Şengör; Özcan, Rıfat; Çetintaş, Süleyman; Yılmaz, Hakan; Ulusoy, ÖzgürWe describe the architecture of an automatic domain-specific Web portal construction system. The system has three major components: i) a focused crawler that collects the domain-specific pages on the Web, ii) an information extraction engine that extracts useful fields from these Web pages, and iii) a query engine that allows both typical keyword based queries on the pages and advanced queries on the extracted data fields. We present a prototype system that works for the course homepages domain on the Web. A user study with the prototype system shows that our approach produces high quality results and achieves better precision figures than the typical keyword based search. Copyright 2007 ACM.Item Open Access Automatic performance evaluation of Web search engines(Elsevier, 2004) Can, F.; Nuray, R.; Sevdik, A. B.Measuring the information retrieval effectiveness of World Wide Web search engines is costly because of human relevance judgments involved. However, both for business enterprises and people it is important to know the most effective Web search engines, since such search engines help their users find higher number of relevant Web pages with less effort. Furthermore, this information can be used for several practical purposes. In this study we introduce automatic Web search engine evaluation method as an efficient and effective assessment tool of such systems. The experiments based on eight Web search engines, 25 queries, and binary user relevance judgments show that our method provides results consistent with human-based evaluations. It is shown that the observed consistencies are statistically significant. This indicates that the new method can be successfully used in the evaluation of Web search engines. © 2003 Elsevier Ltd. All rights reserved.Item Open Access Automatic Ranking of Retrieval Systems in Imperfect Environments(ACM, 2003-07-08) Nuray, Rabia; Can, FazlıThe empirical investigation of the effectiveness of information retrieval (IR) systems requires a test collection, a set of query topics, and a set of relevance judgments made by human assessors for each query. Previous experiments show that differences in human relevance assessments do not affect the relative performance of retrieval systems. Based on this observation, we propose and evaluate a new approach to replace the human relevance judgments by an automatic method. Ranking of retrieval systems with our methodology correlates positively and significantly with that of human-based evaluations. In the experiments, we assume a Web-like imperfect environment: the indexing information for all documents is available for ranking, but some documents may not be available for retrieval. Such conditions can be due to document deletions or network problems. Our method of simulating imperfect environments can be used for Web search engine assessment and in estimating the effects of network conditions (e.g., network unreliability) on IR system performance.Item Open Access Detecting user types in object ranking decisions(ACM, 2009-10) Lu, X.; Schaal, Markus; Adalı, S.; Raju, A. K.With the emergence of Web 2.0 applications, where information is not only shared across the internet, but also syndicated, evaluated, selected, recombined, edited, etc., quality emergence by collaborative effort from many users becomes crucial. However, users may have low expertise, subjective views, or competitive goals. Therefore, we need to identify cooperative users with strong expertise and high objectivity. As a first step towards this aim, we propose criteria for user type classification based on prior work in psychology and derived from observations in Web 2.0. We devise a statistical model for many different user types, and detection methods for those user types. Finally, we evaluate and demonstrate both model and detection methods by means of an experimental setup. Copyright 2009 ACM.Item Open Access E-museum: web-based tour and information system for museums(IEEE, 2006) Baştanlar, Y.; Altıngövde, İsmail Şenol; Aksay, A.; Alav, O.; Çavuş, Özge; Yardımcı, Y.; Ulusoy, Ozgur; Güdükbay, Uğur; Çetin, A. Enis; Akar, G. B.; Aksoy, SelimA web-based system - consisting of data entrance, access and retrieval modules - is constructed for museums. Internet users that visit the e-museum, are able to view the written and visual information belonging to the artworks in the museum, are able to follow the virtual tour prepared for the different sections of the museum, are able to browse the artworks according to certain properties, are able to search the artworks having the similar visual content with the viewed artwork. © 2006 IEEE.Item Open Access eBay in the economic literature: analysis of an auction marketplace(Springer New York LLC, 2010) Hasker, K.; Sickles, R.This survey brings together theoretical and empirical questions that have been addressed in the economic literature on eBay, focusing on understanding the behavior of buyers and sellers. We discuss several puzzles of bidder behavior and the explanations that have been put forward by the literature for each. We then discuss structural estimates of bidder behavior and measuring the consumer surplus derived from eBay. We then try to understand why there are so many selling formats being used simultaneously, and then focus on the critical decision variables for a seller in an eBay English auction. Finally we analyze how trustworthy eBay sellers are on average, and whether the feedback system provides strong incentives for good behavior. © 2010 Springer Science+Business Media, LLC.Item Open Access Energy-price-driven query processing in multi-center web search engines(IEEE, 2011-07) Kayaaslan, Enver; Cambazoglu, B. B.; Blanco, R.; Junqueira, F. P.; Aykanat, CevdetConcurrently processing thousands of web queries, each with a response time under a fraction of a second, necessitates maintaining and operating massive data centers. For large-scale web search engines, this translates into high energy consumption and a huge electric bill. This work takes the challenge to reduce the electric bill of commercial web search engines operating on data centers that are geographically far apart. Based on the observation that energy prices and query workloads show high spatio-temporal variation, we propose a technique that dynamically shifts the query workload of a search engine between its data centers to reduce the electric bill. Experiments on real-life query workloads obtained from a commercial search engine show that significant financial savings can be achieved by this technique.Item Open Access Evolution of web search results within years(ACM, 2011-07) Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, ÖzgürWe provide a first large-scale analysis of the evolution of query results obtained from a real search engine at two distant points in time, namely, in 2007 and 2010, for a set of 630,000 real queries.Item Open Access Exploiting data mining techniques for broadcasting data in mobile computing environments(IEEE, 2002) Saygin, Y.; Ulusoy, ÖzgürMobile computers can be equipped with wireless communication devices that enable users to access data services from any location. In wireless communication, the server-to-client (downlink) communication bandwidth is much higher than the client-to-server (uplink) communication bandwidth. This asymmetry makes the dissemination of data to client machines a desirable approach. However, dissemination of data by broadcasting may induce high access latency in case the number of broadcast data items is large. In this paper, we propose two methods aiming to reduce client access latency of broadcast data. Our methods are based on analyzing the broadcast history (i.e., the chronological sequence of items that have been requested by clients) using data mining techniques. With the first method, the data items in the broadcast disk are organized in such a way that the items requested subsequently are placed close to each other. The second method focuses on improving the cache hit ratio to be able to decrease the access latency. It enables clients to prefetch the data from the broadcast disk based on the rules extracted from previous data request patterns. The proposed methods are implemented on a Web log to estimate their effectiveness. It is shown through performance experiments that the proposed rule-based methods are effective in improving the system performance in terms of the average latency as well as the cache hit ratio of mobile clients.Item Open Access Exploiting query views for static index pruning in web search engines(ACM, 2009-11) Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, ÖzgürWe propose incorporating query views in a number of static pruning strategies, namely term-centric, document-centric and access-based approaches. These query-view based strategies considerably outperform their counterparts for both disjunctive and conjunctive query processing in Web search engines. Copyright 2009 ACM.Item Open Access Issues in the design and implementation of Web-based language courses(Bilkent University, 2003) Bingöl, Azra NihalThis study explored the factors that course designers have taken into account in the design and implementation of web-based courses, how the design and implementation of the web-based courses were effected, and course designers’ views of possible future directions for developing and implementing web-based courses. From the results of this study, some recommendations are made for Bilkent University School of English Language (BUSEL), which is thinking of designing and implementing web-based courses in an English for Foreign Language (EFL) setting. Nine English Language Teaching (ELT) professionals, from different institutions inside and outside of Turkey, participated in this study. A questionnaire was sent to eight participants through email in four different sections. One participant was interviewed as she lives in Ankara, Turkey. The interview consisted of the same questions as the questionnaire. The questionnaire and the interview results were analyzed qualitatively. The data analysis was based on the interpretation of the interview data and the interpretations of patterns emerging from participants’ responses. The data results reveal that it is important to take student concerns, technical concerns, and pedagogical concerns into consideration before designing and implementing web-based courses. The results especially suggest a need for teams of teachers to work together to reduce potential problems in their areas and maximize efficiency in the process. They also call for both teachers and students to receive orientations into the process of web-based instruction before commencing it.Item Open Access Metadata extraction from text in soccer domain(IEEE, 2008-10) Göktürk, Z. O.; Çiçekli, N. K.; Çiçekli, İlyasEvent detection is a crucial part for soccer video searching and querying. The event detection could be done by video content itself or from a structured or semi structured text files gathered from sports web sites. In this paper, we present an approach of metadata extraction from match reports for soccer domain. The UEFA Cup and UEFA Champions League Match Reports are downloaded from the web site of UEFA by a web-crawler. Using regular expressions we annotate these match reports and then extract events from annotated match reports. Extracted events are saved in an MPEG-7 file. We present an interface that is used to query the events in the MPEG-7 match corpus. If an associated match video is available, the video portions that correspond to the found events could be played. © 2008 IEEE.Item Open Access Metadata-based modeling of information resources on the web(Wiley, 2004) Özel, S. A.; Altingövde, S.; Ulusoy, Özgür; Özsoyoǧlu G.; Özsoyoǧlu, Z. M.This paper deals with the problem of modeling Web information resources using expert knowledge and personalized user information for improved Web searching capabilities. We propose a "Web information space" model, which is composed of Web-based information resources (HTML/XML [Hypertext Markup Language/Extensible Markup Language] documents on the Web), expert advice repositories (domain-expert-specified meta-data for information resources), and personalized information about users (captured as user profiles that indicates users' preferences about experts as well as users' knowledge about topics). Expert advice, the heart of the Web information space model, is specified using topics and relationships among topics (called metalinks), along the lines of the recently proposed topic maps. Topics and metalinks constitute metadata that describe the contents of the underlying HTML/XML Web resources. The metadata specification process is semiautomated, and it exploits XML DTDs (Document Type Definition) to allow domain-expert guided mapping of DTD elements to topics and metalinks. The expert advice is stored in an object-relational database management systems (DBMS). To demonstrate the practicality and usability of the proposed Web information space model, we created a prototype expert advice repository of more than one million topics/metalinks for DBLP (Database and Logic Programming) Bibliography data set. We also present a query interface that provides sophisticated querying facilities for DBLP Bibliography resources using the expert advice repository.Item Open Access A new approach to search result clustering and labeling(Springer, Berlin, Heidelberg, 2011) Türel, Anıl; Can, FazlıSearch engines present query results as a long ordered list of web snippets divided into several pages. Post-processing of retrieval results for easier access of desired information is an important research problem. In this paper, we present a novel search result clustering approach to split the long list of documents returned by search engines into meaningfully grouped and labeled clusters. Our method emphasizes clustering quality by using cover coefficient-based and sequential k-means clustering algorithms. A cluster labeling method based on term weighting is also introduced for reflecting cluster contents. In addition, we present a new metric that employs precision and recall to assess the success of cluster labeling. We adopt a comparative strategy to derive the relative performance of the proposed method with respect to two prominent search result clustering methods: Suffix Tree Clustering and Lingo. Experimental results in the publicly available AMBIENT and ODP-239 datasets show that our method can successfully achieve both clustering and labeling tasks. © 2011 Springer-Verlag Berlin Heidelberg.Item Open Access Re-ranking of web image search results using a graph algorithm(IEEE, 2008-12) Zitouni, Hilal; Sevil, Sare; Özkan, Derya; Duygulu, PınarWe propose a method to improve the results of image search engines on the Internet to satisfy users who desire to see relevant images in the first few pages. The method re-ranks the results of text based systems by incorporating visual similarity of the resulting images. We observe that, together with many unrelated ones, results of text based systems include a subset of correct images, and this set is, in general, the largest one which has the most similar images compared to other possible subsets. Based on this observation, we present similarities of all images in a graph structure, and find the densest component that corresponds to the largest set of most similar subset of images. Then, to re-rank the results, we give higher priority to the images in the densest component, and rank the others based on their similarities to the images in the densest component. The experiments are carried out on 18 category of images from [8]. © 2008 IEEE.Item Open Access Recognizing faces in news photographs on the web(IEEE, 2009-09) Zitouni, Hilal; Bulut, Muhammed Fatih; Duygulu, PınarWe propose a graph based method in order to recognize the faces that appear on the web using a small training set. First, relevant pictures of the desired people are collected by querying the name in a text based search engine in order to construct the data set. Then, detected faces in these photographs are represented using SIFT features extracted from facial features. The similarities of faces are represented in a graph which is then used in random walk with restart algorithm to provide links between faces. Those links are used for recognition by using two different methods. © 2009 IEEE.Item Open Access Replacement problem in Web caching(IEEE, 2003-06-07) Çakıroğlu, Seda; Arıkan, ErdalCaching has been recognized as an effective scheme for avoiding service bottleneck and reducing network traffic in World Wide Web. Our work focuses on the replacement problem in Web caching, which arises due to limited storage. We seek the best configuration for a fully connected network of N caches. The problem is formulated as a discrete optimization problem. A number of low complexity heuristics are studied to obtain approximate solutions. Performances are tested under fictitious probabilistic request sequences access logs of real Web traffic. LFD (longest-forward-distance), the classical optimal off-line paging algorithm, is observed not to be optimal. Instead a window scheme should be used. Under an unchanging request pattern, a simple static placement algorithm achieves the maximum hit rates using the arrival probabilities. Otherwise, for quick adaptation to changing requests and for better worst-case performances a randomized algorithm should be chosen. We also give an analysis of Web data to propose best heuristics for its characteristics. © 2003 IEEE.