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Indexing valid time intervals [chapter]

Tolga Bozkaya, Meral Ozsoyoglu
1998 Lecture Notes in Computer Science  
To support temporal operators and to increase the efficiency of temporal queries, indexing based on temporal attributes is required. We consider the problem of indexing the temporal dimension in valid time databases. We assume that the temporal information of data objects are represented as valid time intervals that have to be managed dynamically by an efficient index structure. Unlike the time intervals in transaction time databases, valid time intervals can be inserted, deleted, and modified
more » ... t any point in time. Furthermore, their lifespans can go beyond the current time point and extend into the future. We propose an indexing scheme that uses augmented B+trees called Interval B+trees for indexing a dynamic set of valid time intervals. Interval B+trees (IB+trees) use beginning points of the intervals as key points and keep maximum end point information of its subtrees for each internal node. We introduce an algorithm to apply time-splits at the leaf level of the IB+tree that would partition long valid time intervals into disjoint subintervals and distribute them among several leaf nodes to increase efficiency of search operation, especially for timeslice queries. We compared IB+trees with time-splits to one dimensional R-trees and observed that while their performances for timeslice queries are comparable, IB+trees are far more superior for many temporal queries that are based on beginning points of time intervals. This is expected as the IB+trees use the beginning points of intervals as keys and therefore support such queries naturally. We also show the extensions to our indexing scheme for handling open ended valid time intervals (valid time intervals whose lifespans extend into future indefinitely), and valid time intervals whose end points move along the current timeline.
doi:10.1007/bfb0054512 fatcat:b5ara3wl2jhjvmyflp4oflbqxm

Distance-based indexing for high-dimensional metric spaces

Tolga Bozkaya, Meral Ozsoyoglu
1997 SIGMOD record  
In many database applications, one of the common queries is to find approximate matches to a given query item from a collection of data items. For example, given an image database, one may want to retrieve all images that are similar to a given query image. Distance based index structures are proposed for applications where the data domain is high dimensional, or the distance function used to compute distances between data objects is non-Euclidean. In this paper, we introduce a distance based
more » ... dex structure called multi-vantage point (mvp) tree for similarity queries on high-dimensional metric spaces. The mvptree uses more than one vantage point to partition the space into spherical cuts at each level. It also utilizes the pre-computed (at construction time) distances between the data points and the vantage points. We have done experiments to compare mvp-trees with vp-trees which have a similar partitioning strategy, but use only one vantage point at each level, and do not make use of the pre-computed distances. Empirical studies show that mvptree outperforms the vp-tree 20% to 80% for varying query ranges and different distance distributions.
doi:10.1145/253262.253345 fatcat:xwwra6arz5fe5ayx2tnavxw2n4

Business Modeling Using SQL Spreadsheets [chapter]

Andrew Witkowski, Srikanth Bellamkonda, Tolga Bozkaya, Nathan Folkert, Abhinav Gupta, Lei Sheng, Sankar Subramanian
2003 Proceedings 2003 VLDB Conference  
One of the critical deficiencies of SQL is the lack of support for array and spreadsheet like calculations which are frequent in OLAP and Business Modeling applications. Applications relying on SQL have to emulate these calculations using joins, UNION operations, Window Functions and complex CASE expressions. The designated place in SQL for algebraic calculations is the SELECT clause, which is extremely limiting and forces applications to generate queries with nested views, subqueries and
more » ... x joins. This distributes Business Modeling computations across many query blocks, making applications coded in SQL hard to develop. The limitations of RDBMS have been filled by spreadsheets and specialized MOLAP engines which are good at formulas for mathematical modeling but lack the formalism of the relational model, are difficult to manage, and exhibit scalability problems. This demo presents a scalable, mathematically rigorous, and performant SQL extensions for Relational Business Modeling, called the SQL Spreadsheet. We present examples of typical Business Modeling computations with SQL spreadsheet and compare them with the ones using standard SQL showing performance advantages and ease of programming for the former. We will show a scalability example where data is processed in parallel and will present a new class of query optimizations applicable to SQL spreadsheet.
doi:10.1016/b978-012722442-8/50119-1 dblp:conf/vldb/WitkowskiBBFGSS03 fatcat:7uivilf6hbf4bg7fjppv6syeji

Indexing large metric spaces for similarity search queries

Tolga Bozkaya, Meral Ozsoyoglu
1999 ACM Transactions on Database Systems  
Bozkaya and M. Ozsoyoglu Table IV .  ...  Bozkaya and M. Ozsoyoglu in every node recording the center point (routing object) and the covering radius for each partition.  ... 
doi:10.1145/328939.328959 fatcat:k2xqxbkqbrcl7kofz6taps7n6a

Comment on "Origin and evolution of hydrothermal fluids in epithermal Pb-Zn-Cu + Au + Ag deposits at Koru and Tesbihdere mining districts, Canakkale, Biga Peninsula, NW Turkey" by Mustafa Cicek and Tolga Oyman, [Ore Geology Review, 2016, 78, 176–195]

David A. Banks, Gulcan Bozkaya, Omer Bozkaya
2017 Ore Geology Reviews  
This was clearly shown in the papers by Bozkaya et al (2014) and Bozkaya and Banks (2015) , which the authors have chosen to ignore in their discussions and interpretations.  ...  (Bozkaya et al., 2007) . There is no definitive proof to exclude other possibilities.  ... 
doi:10.1016/j.oregeorev.2016.10.022 fatcat:4ilmim3vwngeppokfa3ksr4ery

Distance-based indexing for high-dimensional metric spaces

Tolga Bozkaya, Meral Ozsoyoglu
1997 Proceedings of the 1997 ACM SIGMOD international conference on Management of data - SIGMOD '97  
In many database applications, one of the common queries is to find approximate matches to a given query item from a collection of data items. For example, given an image database, one may want to retrieve all images that are similar to a given query image. Distance based index structures are proposed for applications where the data domain is high dimensional, or the distance function used to compute distances between data objects is non-Euclidean. In this paper, we introduce a distance based
more » ... dex structure called multi-vantage point (mvp) tree for similarity queries on high-dimensional metric spaces. The mvptree uses more than one vantage point to partition the space into spherical cuts at each level. It also utilizes the pre-computed (at construction time) distances between the data points and the vantage points. We have done experiments to compare mvp-trees with vp-trees which have a similar partitioning strategy, but use only one vantage point at each level, and do not make use of the pre-computed distances. Empirical studies show that mvptree outperforms the vp-tree 20% to 80% for varying query ranges and different distance distributions.
doi:10.1145/253260.253345 dblp:conf/sigmod/BozkayaO97 fatcat:7zqybhoebfb5rnlo4cjglcdeze

Spreadsheets in RDBMS for OLAP

Andrew Witkowski, Srikanth Bellamkonda, Tolga Bozkaya, Gregory Dorman, Nathan Folkert, Abhinav Gupta, Lei Shen, Sankar Subramanian
2003 Proceedings of the 2003 ACM SIGMOD international conference on on Management of data - SIGMOD '03  
One of the critical deficiencies of SQL is lack of support for ndimensional array-based computations which are frequent in OLAP environments. Relational OLAP (ROLAP) applications have to emulate them using joins, recently introduced SQL Window Functions [18] and complex and inefficient CASE expressions. The designated place in SQL for specifying calculations is the SELECT clause, which is extremely limiting and forces the user to generate queries using nested views, subqueries and complex
more » ... Furthermore, SQL-query optimizer is pre-occupied with determining efficient join orders and choosing optimal access methods and largely disregards optimization of complex numerical formulas. Execution methods concentrated on efficient computation of a cube [11], [16] rather than on random access structures for inter-row calculations. This has created a gap that has been filled by spreadsheets and specialized MOLAP engines, which are good at formulas for mathematical modeling but lack the formalism of the relational model, are difficult to manage, and exhibit scalability problems. This paper presents SQL extensions involving array based calculations for complex modeling. In addition, we present optimizations, access structures and execution models for processing them efficiently.
doi:10.1145/872757.872767 dblp:conf/sigmod/WitkowskiBBDFGSS03 fatcat:g6f52zdz6jfnja3cneqzhqd2mu

Spreadsheets in RDBMS for OLAP

Andrew Witkowski, Srikanth Bellamkonda, Tolga Bozkaya, Gregory Dorman, Nathan Folkert, Abhinav Gupta, Lei Shen, Sankar Subramanian
2003 Proceedings of the 2003 ACM SIGMOD international conference on on Management of data - SIGMOD '03  
One of the critical deficiencies of SQL is lack of support for ndimensional array-based computations which are frequent in OLAP environments. Relational OLAP (ROLAP) applications have to emulate them using joins, recently introduced SQL Window Functions [18] and complex and inefficient CASE expressions. The designated place in SQL for specifying calculations is the SELECT clause, which is extremely limiting and forces the user to generate queries using nested views, subqueries and complex
more » ... Furthermore, SQL-query optimizer is pre-occupied with determining efficient join orders and choosing optimal access methods and largely disregards optimization of complex numerical formulas. Execution methods concentrated on efficient computation of a cube [11], [16] rather than on random access structures for inter-row calculations. This has created a gap that has been filled by spreadsheets and specialized MOLAP engines, which are good at formulas for mathematical modeling but lack the formalism of the relational model, are difficult to manage, and exhibit scalability problems. This paper presents SQL extensions involving array based calculations for complex modeling. In addition, we present optimizations, access structures and execution models for processing them efficiently.
doi:10.1145/872766.872767 fatcat:3rlgkitm5vds7f3d3rstnyqtem

Research Trends in Turkish Distance Education: A Content Analysis of Dissertations, 1986-2014

Aras Bozkurt, Evrim Genc Kumtepe, Alper Tolga Kumtepe, İrem Erdem Aydın, Müjgan Bozkaya, Cengiz Hakan Aydın
2015 European Journal of Open, Distance and E-Learning  
This paper presents a content analytic approach on doctoral dissertations in the field of distance education in Turkish Higher Education context from the years of 1986 through 2014. A total of 61 dissertations were examined to explore keywords, academic discipline, research areas, theoretical/conceptual frameworks, research designs, research models, tests and analyses, data collection tools, participants, variables/research interests, and leading contributor institutions. It is believed that
more » ... s study can be beneficial to the field of distance education in Turkish context to identify research trends and set a research agenda by exploring dissertations that were published between 1986 and 2014.
doi:10.1515/eurodl-2015-0010 fatcat:4g5wkcpr3bdrfdp2sxbcekafmy

Multicenter Analysis of Gestational Trophoblastic Neoplasia in Turkey

Sabit Sinan Ozalp, Elcin Telli, Tufan Oge, Gokhan Tulunay, Nurettin Boran, Taner Turan, Mufit Yenen, Zehra Kurdoglu, Ali Ozler, Kunter Yuce, Volkan Ulker, Macit Arvas (+41 others)
2014 Asian Pacific Journal of Cancer Prevention  
To evaluate the incidence, diagnosis and management of GTN among 28 centers in Turkey. Materials and Methods: A retrospective study was designed to include GTN patients attending 28 centers in the 10-year period between January 2003 and May 2013. Demographical characteristics of the patients, histopathological diagnosis, the International Federation of Gynecology and Obstetrics (FIGO) anatomical and prognostic scores, use of single-agent and multi-agent chemotherapy, surgical interventions and
more » ... rognosis were evaluated. Results: From 2003-2013, there were 1,173,235 deliveries and 456 GTN cases at the 28 centers. The incidence was calculated to be 0.38 per 1,000 deliveries. According to the evaluated data of 364 patients, the median age at diagnosis was 31 years (range, 15-59 years). A histopathological diagnosis was present for 45.1% of the patients, and invasive mole, choriocarcinoma and PSTTs were diagnosed in 22.3% (n=81), 18.1% (n=66) and 4.7% (n=17) of the patients, respectively. Regarding final prognosis, 352 (96.7%) of the patients had remission, and 7 (1.9%) had persistence, whereas the disease was mortal for 5 (1.4%) of the patients. Conclusions: Because of the differences between countries, it is important to provide national registration systems and special clinics for the accurate diagnosis and treatment of GTN.
doi:10.7314/apjcp.2014.15.8.3625 fatcat:dx3tohfutzh65at3smrs5zmdz4

Az MVP fa hatékonyságának vizsgálata, implementációja

Zoltán Krizsán
2002 Fiatal Műszakiak Tudományos Ülésszaka  
[l]Tolga Bozkaya, Meral Ozsologlu: DISTANCE-BASED INDEXING FOR HIGH-DIMENSIONAL METRIC SPACES [2] Tolga Bozkaya, Meral Ozsologlu: INDEXING LARGE METRIC SPACES FOR SIMILARITY SEARCH QUERIES Krizsán Zoltán  ... 
doi:10.36243/fmtu-2002.39 fatcat:hskxqhvfyfhbxl5gh6r4boxshq

Frontmatter

2020 Turk biyokimya dergisi = Turkish journal of biochemistry  
Mohamed Erdal Simsek, Gulcin Simsek, Mehmet Fazil Tolga Soyal, Pinar Kaygin, Ali Cemal Duzgun, Sezen Sarialtin, Sadi Kaplan and Serpil Oguztuzun New pathway in rheumatic mitral valve disease: cytochrome  ...  Nazmi Can Doğan, Merve Aktar, Alev Mahşer, Gizem Yıldırım, Ali Serel and Erhan Tatar Analysis of blood gas beyond bicarbonate in outpatients with stage 3-5 chronic kidney disease 891 Murat Aksit, Giray Bozkaya  ... 
doi:10.1515/tjb-2020-frontmatter6 fatcat:wekujbp5qzccbjedewjma7az3q

Çocuk ve Savaş Yazar Dizini

A Filiz, Yetimakman
unpublished
, S66 Timur Meşe, S150 Tolga Altuğ Şen, S87 Tolga İnce, S39, S73 Tuba Giray, S74 Tuba Koçkar, S1, S2, S3, S122 Tufan Kutlu, S48, S49, S64, S74 Tuğba Koca, S41, S50, S51, S52, S77 Tuğba Zengin, S84, S105  ...  Tiraje Çelkan, S64 Tamay Gürbüz, S101 Tamer Karaaslan, S30 Taner Atılgan, S136 Taner Hafızoğlu, S137 Tanyel Zübarioğlu, S113, S114, S115, S116, S117 Tarık Kırkgöz, S180 Thony Beat, S115 Tijen Alkan Bozkaya  ... 
fatcat:34buku6zsbbkjaq6tsdylux75i

SURİYELİ MÜLTECİ KRİZİNİN TÜRKİYE VE AVRUPA BİRLİĞİ İLİŞKİSİNE YANSIMASI: DÜNYA SİSTEMLERİ ANALİZİ ÜZERİNDEN BİR DEĞERLENDİRME

Tolga ÖZTÜRK, Ece BOYACI
2022 Alanya Akademik Bakış  
Buna ek olarak 3 milyar Euro daha verileceği açıklanmış ve toplamda 6 milyar Euro'luk ödeme yapılmıştır (Bozkaya ve Kıncal, 2018: 115) . 2021 yılında ise Avrupa Parlamentosu'nda onaylandıktan sonra göç  ...  bulundurulursa Avrupa Birliği'nin dış sınır güvenliği için Türkiye'yle uyum içerisinde kalıp bir iş birliği yapması zorunludur çünkü Suriyeliler, Avrupa Birliği için büyük bir sorunu teşkil etmektedir (Bozkaya  ... 
doi:10.29023/alanyaakademik.1035028 fatcat:3gerx5e6vvgfhorsvybsaxrmyy

Çataltepe (Lapseki-Çanakkale) Pb-Zn±Cu±Ag Yatağı'nın Jeolojisi ve Alterasyon Özellikleri

Gökhan DEMİRELA, Sinan AKISKA, İ. Sönmez SAYILI, İlkay KUŞCU
2014 Yerbilimleri/Hacettepe Üniversitesi Yerbilimleri Uygulama ve Araştırma Merkezi Dergisi  
ye ve bu makalenin son şeklini almasını sağlayan hakemler (Tolga Oyman ve diğer anonim hakem) ile baş editör Yurdal Genç'e teşekkür ederler.  ...  ve Gökçe, 2009; Bozkaya, 2011; İlbars vd., 2010 (Akıska, 2010; Akıska vd., 2010; Akıska vd., 2013) .  ... 
doi:10.17824/huyuamd.20100 fatcat:2ktczix7o5dejifoucwz3a5jbq
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