Browsing by Subject "Metadata"

Now showing 1 - 14 of 14

Open Access
Activity recognition invariant to sensor orientation with wearable motion sensors
(MDPI AG, 2017) Yurtman, A.; Barshan, B.
Most activity recognition studies that employ wearable sensors assume that the sensors are attached at pre-determined positions and orientations that do not change over time. Since this is not the case in practice, it is of interest to develop wearable systems that operate invariantly to sensor position and orientation. We focus on invariance to sensor orientation and develop two alternative transformations to remove the effect of absolute sensor orientation from the raw sensor data. We test the proposed methodology in activity recognition with four state-of-the-art classifiers using five publicly available datasets containing various types of human activities acquired by different sensor configurations. While the ordinary activity recognition system cannot handle incorrectly oriented sensors, the proposed transformations allow the sensors to be worn at any orientation at a given position on the body, and achieve nearly the same activity recognition performance as the ordinary system for which the sensor units are not rotatable. The proposed techniques can be applied to existing wearable systems without much effort, by simply transforming the time-domain sensor data at the pre-processing stage. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
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.
Restricted
Bilkent Üniversitesi kurumsal arşivi "Institutional Repository"
(Bilkent University Library, 2015-04-28) Korkmaz, Taner
Kurumsal arşiv sistemi, bilginin daha hızlı ve daha çok kişiye kolayca ulaştırılmasını, yeni çalışmalar için kaynaklara kolay erişim ayrıcalığının sağlanması, daha önce aynı konuda neler yapıldığının kolayca belirlenmesi, yayınlara daha çok atıf yapılmasının sağlamasının yanında, araştırmacıların ve üniversitenin saygınlıklarının artmasını sağlar. Kurumsal arşiv sistemi, üniversitemizin entelektüel mirasını toplama, uzun dönem saklama işlevini yerine getirir ve geniş kitlelerin erişimine imkan sağlayacak biçimde yapılandırılır. Kurumsal arşiv sisteminde, birimlerce üretilen kitap, makale, bildiri, tez, proje, ödev, ders notu, mikroform, teknik rapor, fotoğraf, harita, ön baskı, veri setleri, ses ve video dosyaları gibi akademik dokümanlar derlenir.
Open Access
Compression of images in CFA format
(IEEE, 2006) Cüce, Halil İbrahim; Çetin, A. Enis; Davey, M. K.
In this paper, images in Color Filter Array (CFA) format are compressed without converting them to full-RGB color images. Green pixels are extracted from the CFA image data and placed in a rectangular array, and compressed using a transform based method without estimating the corresponding luminance values. In addition, two sets of color difference (or chrominance) coefficients are obtained corresponding to the red and blue pixels of the CFA data and they are also compressed using a transform based method. The proposed method produces better PSNR values compared to the standard approach of bilinear interpolation followed by compression.
Open Access
Database research at Bilkent University
(ACM, 2005) Ulusoy, Özgür
The research activities of the Database Research Group of Bilkent University are discussed. The research is mainly focused on the topics of multimedia databases, Web databases, and mobile computing. The Ottoman Archive Content-Based Retrieval system is a Web-based program that provides electronic access to digitally stored Ottoman document images. The issues involved in adding a native score management system to object-relational databases, to be used in querying web metadata are also discussed.
Open Access
Efficient discovery of join plans in schemaless data
(ACM, 2009-09) Acar, Aybar C.; Motro, A.
We describe a method of inferring join plans for a set of relation instances, in the absence of any metadata, such as attribute domains, attribute names, or constraints (e.g., keys or foreign keys). Our method enumerates the possible join plans in order of likelihood, based on the compatibility of a pair of columns and their suitability as join attributes (i.e. their appropriateness as keys). We outline two variants of the approach. The first variant is accurate but potentially time-consuming, especially for large relations that do not fit in memory. The second variant is an approximation of the former and hence less accurate, but is considerably more efficient, allowing the method to be used online, even for large relations. We provide experimental results showing how both forms scale in terms of performance as the number of candidate join attributes and the size of the relations increase. We also characterize the accuracy of the approximate variant with respect to the exact variant. Copyright ©2009 ACM.
Open Access
Implementation of a topic map data model for a Web-based information resource
(2002) Kutlutürk, Mustafa
The Web has become a vast information resource in recent years. Millions of people use the Web on a regular basis and the number is increasing rapidly. The Web is the largest center in the world presenting almost all of the social, economical, educational, etc. activities and anyone from all over the word can visit this huge place even though he does not have to stand up from his sit. Due to its hugeness, finding desired data on the Web in a timely and cost effective way is a problem of wide interest. In the last several years, many search engines have been created to help Web users find desired information. However, most of these search engines employ topic-independent search methods that rely heavily on keyword-based approaches where the users are presented with a lot of unnecessary search results. In this thesis, we present a data model using topic maps standards for Webbased information resources. In this model, topics, topic associations and topic occurrences (called as topic metalinks and topic sources in this study) are the fundamental concepts. In fact, the presented model is a metadata model that describes the content of the Web-based information resource and creates virtual knowledge maps over the modeled information resource. Thus, semantic indexing of the Web-based information resource is performed for allowing efficient search and querying the data on the resource. iv Additionally, we employ full text indexing in the presented model by using a widely accepted method that is inverted file index. Due to the rapid increase of data, the dynamic update of the inverted file index during the addition of new documents is inevitable. We have implemented an efficient dynamic update scheme in the presented model for the employed inverted file index method. The presented topic map data model provides combining the powers of both keyword-based search and topic-centric search methods. We also provide a prototype search engine verifying that our presented model contributes very much to the problem of efficient and effective search and querying of the Web-based information resources.
Open Access
Integration of structural and semantic models for multimedia metadata management
(IEEE, 2007-06) Little, S.; Martinelli, M.; Salvetti, O.; Güdükbay, Uğur; Ulusoy, Özgür; De Chalendar, G.; Grefenstette, G.
The management and exchange of multimedia data is challenging due to the variety of formats, standards and intended applications. In addition, production of multimedia data is rapidly increasing due to the availability of off-the-shelf, modern digital devices that can be used by even inexperienced users. It is likely that this volume of information will only increase in the future. A key goal of the MUSCLE (Multimedia Understanding through Semantics, Computation and Learning) network is to develop tools, technologies and standards to facilitate the interoperability of multimedia content and support the exchange of such data. One approach for achieving this was the creation of a specific "E-Team", composed of the authors, to discuss core questions and practical issues based on the participant's individual work. In this paper, we present the relevant points of view with regards to sharing experiences and to extracting and integrating multimedia data and metadata from different modes (text, images, video). © 2007 IEEE.
Open Access
Metadata extraction from text in soccer domain
(IEEE, 2008-10) Göktürk, Z. O.; Çiçekli, N. K.; Çiçekli, İlyas
Event 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.
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.
Open Access
PetaShare: A reliable, efficient and transparent distributed storage management system
(2011) Kosar, T.; Akturk I.; Balman, M.; Wang X.
Modern collaborative science has placed increasing burden on data management infrastructure to handle the increasingly large data archives generated. Beside functionality, reliability and availability are also key factors in delivering a data management system that can efficiently and effectively meet the challenges posed and compounded by the unbounded increase in the size of data generated by scientific applications. We have developed a reliable and efficient distributed data storage system, PetaShare, which spans multiple institutions across the state of Louisiana. At the back-end, PetaShare provides a unified name space and efficient data movement across geographically distributed storage sites. At the front-end, it provides light-weight clients the enable easy, transparent and scalable access. In PetaShare, we have designed and implemented an asynchronously replicated multi-master metadata system for enhanced reliability and availability, and an advanced buffering system for improved data transfer performance. In this paper, we present the details of our design and implementation, show performance results, and describe our experience in developing a reliable and efficient distributed data management system for data-intensive science. © 2011 - IOS Press and the authors. All rights reserved.
Open Access
Querying web metadata: Native score management and text support in databases
(Association for Computing Machinery, 2004) Özsoyoǧlu, G.; Altingövde, I. S.; Al-Hamdani, A.; Özel, S. A.; Ulusoy, Özgür; Özsoyoǧlu, Z. M.
In this article, we discuss the issues involved in adding a native score management system to object-relational databases, to be used in querying Web metadata (that describes the semantic content of Web resources). The Web metadata model is based on topics (representing entities), relationships among topics (called metalinks), and importance scores (sideway values) of topics and metalinks. We extend database relations with scoring functions and importance scores. We add to SQL score-management clauses with well-defined semantics, and propose the sidewayvalue algebra (SVA), to evaluate the extended SQL queries. SQL extensions and the SVA algebra are illustrated through two Web resources, namely, the DBLP Bibliography and the SIGMOD Anthology. SQL extensions include clauses for propagating input tuple importance scores to output tuples during query processing, clauses that specify query stopping conditions, threshold predicates (a type of approximate similarity predicates for text comparisons), and user-defined-function-based predicates. The propagated importance scores are then used to rank and return a small number of output tuples. The query stopping conditions are propagated to SVA operators during query processing. We show that our SQL extensions are well-defined, meaning that, given a database and a query Q, under any query processing scheme, the output tuples of Q and their importance scores stay the same. To process the SQL extensions, we discuss two sideway value algebra operators, namely, sideway value algebra join and topic closure, give their implementation algorithms, and report their experimental evaluations.
Open Access
Topic-Centric Querying of Web Information Resourcest
(Springer, Berlin, Heidelberg, 2001) Altıngövde, İsmail Şengör; Özel, Selma A.; Ulusoy, Özgür; Özsoyoğlu G.; Özsoyoğlu, Z.M.
This paper deals with the problem of modeling web information resources using expert knowledge and personalized user information, and querying them in terms of topics and topic relationships. We propose a model for web information resources, and a query language SQL-TC (Topic-Centric SQL) to query the model. The model is composed of web-based information resources (XML or HTML documents on the web), expert advice repositories (domain-expert-specified metadata for information resources), and personalized information about users (captured as user profiles, that indicate users’ preferences as to which expert advice they would like to follow, and which to ignore, etc). The query language SQL-TC makes use of the metadata information provided in expert advice repositories and embedded in information resources, and employs user preferences to further refine the query output. Query output objects/tuples are ranked with respect to the (expert-judged and user- preference-revised) importance values of requested topics/metalinks, and the query output is limited by either top n-ranked objects/tuples, or objects/tuples with importance values above a given threshold, or both. © Springer-Verlag Berlin Heidelberg 2001.
Open Access
Turkish keyphrase extraction using KEA
(IEEE, 2007-11) Pala, Nagehan; Çiçekli, İlyas
Keyphrases provide semantic metadata to summarize and characterize documents. Unfortunately, there are many digital documents especially on the Internet that do not have a list of assigned keyphrases. Assigning keyphrases to these documents manually is a tedious process and requires knowledge of the subject. Automatic Keyphrase Extraction solves this problem. In this paper, we present implementation of Keyphrase Extraction Algorithm (KEA) for Turkish as well as extending it with new features to improve its performance. ©2007 IEEE.