İçerik Tabanlı Görüntü Erişimi

Digital image collections are expanding day by day, and image retrieval becomes even harder. Both individuals and institutions encounter serious problems when building their image archives and later when retrieving the archived images. Visual information cannot be fully expressed in words and normally depends on intuitive human perception. Consequently, this causes us to find the plain text-based information inadequate, and as a result, increases the value of the visual content. However describing, storing and retrieving the visual content is not simple. The research activities in this area, which escalated in the 90’s, have brought several solutions to the understanding,design and development of the image retrieval systems. This article reviews the studies on image retrieval systems in general, and content-based image retrieval systems specifically. The article also examines the features of content-based image retrieval systems

Anticausal inverses for IIR filter banks, quincunx wavelets and image coding

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Content-Based Image Retrieval Systems

Digital image collections are expanding day by day, and imageretrieval becomes even harder. Both individuals and institutionsencounter serious problems when building their image archives andlater when retrieving the archived images. Visual information cannot be fully expressed in words and normally depends on intuitive humanperception. Consequently, this causes us to find the plain text-basedinformation inadequate, and as a result, increases the value of thevisual content. However describing, storing and retrieving the visualcontent is not simple. The research activities in this area, whichescalated in the 90’s, have brought several solutions to the under-standing, design and development of the image retrieval systems. Thisarticle reviews the studies on image retrieval systems in general, andcontent-based image retrieval systems specifically. The article alsoexamines the features of content-based image retrieval systems

Türkiye'nin Bilimsel Yayınlarının Sosyal Ağ Analizi Yöntemiyle Değerlendirilmesi

Scientists publish their studies in order to announce the research results to a wide audience. The impact of published works is measured and examined qualitatively by bibliometric methods. By means of research evaluation studies, publication tendencies of specific fields are revealed, comparisons are made between countries, institutions or individuals, and consequently all these efforts help the formation of scientific publication policies of countries and institutions. Research evaluation studies also provide information on what is worth researching for the scientists and whatis valuable for the academia.The aim of this project is to examine Turkey’s scientific publications in the citation indexes in terms of their bibliometric features to reveal the relationships among the authors, institutions and countries by using the social network analysis method. Social network analysis is used by several disciplines to examine the relationships of communities, to describe their network structures and to visualise and model the existing nodes which cannot be observed with the naked eye. In this project, Turkey’s partners in producing scientific publications, institutional co-operations, commonly cited journals were also investigated.The research started by obtaining Turkey addressed publications from the Science Citation Index Expanded, Social Sciences Citation Indexand Arts & Humanities Citation Indexdatabases of Web of Knowledge. An extensive data cleaning process was performed on the obtained data in order to be able to make reliable evaluations.In this data cleaning process somefields, such as address, publication date, publication type, of almost 200,000 records were verified by different techniques.The data cleaning process is an obligation in such projects to be able to achieve accurate results and it takes considerable time. In our study different softwares were used and several macros were produced in order to correct errors generated from the databases. It is also important to perform a visual inspection along with the computer based examinations to be able to detect the possible errors and create a proper and accurate data set. Therefore the project staff spent most of their times for checking and creating this correct database.This project contains the most comprehensive analysis results which target Turkey’s scientificpublications within the international literature. Studies that used the citation indexes as their data sets usually perform superficial evaluations. With this study, Turkey’s tendency for the process of producing scientific publications and the scientificcommunication with other disciplines were investigated longitudinally. The findings of this project will help the decision makers to take informed decisions on scientific publication policy.Bilim insanları yaptıkları çalışmaların sonuçlarını geniş kesimlere duyurabilmek için araştırma sonuçlarını yayımlamaktadır. Yayımlanan çalışmaların etkinliği bibliyometrik araştırmalarla ölçülmekte ve niteliksel olarak sorgulanmaktadır. Araştırma değerlendirme çalışmaları ile disiplinlere özgü yayın yapma eğilimleri ortaya çıkmakta, kişiler, kurumlar ya da ülkeler arasında karşılaştırmalar yapılmakta, ülkelerin veya kurumların bilimsel yayın politikaları şekillenmektedir. Aynı zamanda araştırma değerlendirme çalışmaları neyin araştırma yapmaya değer olduğunu ve bilim camiasının nelere değer verdiğini göstermektedir.Bu projenin amacı Türkiye’nin atıf dizinleri kapsamındaki bilimsel yayınlarını bibliyometrik özellikleri açısından incelemek, sosyal ağ analizi aracılığıyla yazarlar, kurumlar ve ülkeler arasındaki ilişkileri ortaya çıkarmaktır. Sosyal ağ analizi birçok disiplin tarafından sıklıkla kullanılan bir yöntem olup, toplulukların yapısını incelemek, ağ yapılarını betimlemek ve topluluklar arasında kolayca gözlemlenemeyen ilişkileri görselleştirerek var olan bağlantıları modellemek için kullanılmaktadır. Proje kapsamında ayrıca, Türkiye’nin ortak yayın faaliyetinde bulunduğu ülkeler, kurumlararası işbirlikleri, ortak atıf yapılan dergiler de incelenmiştir. Araştırmayı gerçekleştirmek amacıyla ilk olarak Web of Knowledgeiçerisinde yer alan Science Citation Index Expanded, Social Sciences Citation Indexve Arts & Humanities Citation Indexveri tabanlarındaki Türkiye adresli yayınlar elde edilmiştir. Söz konusu yayınlar elde edildikten sonra değerlendirmelerin sağlıklı bir şekilde yapılabilmesi için kapsamlı bir veri temizleme işlemi gerçekleştirilmiştir. Veri temizleme işleminde yaklaşık 200.000 kayda ait adres, yayın yılı, yayın türügibi bilgilerinfarklı tekniklerle doğrulaması yapılmıştır. Bu tip projelerdedoğru sonuçlar elde edebilmek içinyapılması zorunlu olan veri temizleme işlemi oldukça fazla zaman almaktadır.Çalışmamızda da veri temizleme süreci boyunca farklı yazılımlardan yararlanılmış, çeşitli makrolar yazılarakveri tabanı kaynaklı hatalar düzeltilmiştir. Olası hataların saptanıp veri setinin tam ve doğru şekilde oluşturulmasında bilgisayar yardımının yanı sıra gözle yapılan kontrollerin önemi büyüktür. Bu nedenle proje çalışanları projeye ayırdıkları zamanlarının önemli bir kısmını söz konusu verileri kontrol etmekle geçirmişlerdir.Bu proje Türkiye’nin uluslararası literatürdekiyayınlarına ilişkin şimdiye kadar yapılmış en kapsamlı analiz sonuçlarını içermektedir. Veri kaynağı olarak atıf dizinlerinin kullanıldığı çalışmalarda genellikle yüzeysel değerlendirmeler ön plana çıkmaktadır. Bu çalışma ile Türkiye’nin bilimsel yayın yapma sürecindeki eğilimi ve farklı disiplinlerdeki bilimsel iletişimin ne şekilde gerçekleştirildiği konuları uzunlamasına araştırılmıştır. Proje sonucunda elde edilen bulgular ile kişi ve ve kurumların bilimsel yayın politikasına yönelik sağlıklı kararlar alabilmesi için gerekli olan arka plan bilgiler elde edilmiştir

The Evaluation of Scientific Publications of Hacettepe University Using Social Network Analysis Method

Hacettepe University is the most productive institution of Turkey in terms of scientific publications which are included in the citation indexes. In this study, Hacettepe University- addressed publications are analyzed with regard to their bibliometric features from the year when first Hacettepe University-addressed publication took its place in citation indexes (1968) to 2009. Bibliographic data obtained from these were evaluated by the social network analysis method. Social network analysis is an interdisciplinary study and is often used in many different fields. It also examines the structure of communities, tries to describe the constructions of networks and models the existing connections by visualizing the relationships between the communities. Following research questions were addressed in this study: 1) What is the level of productivity of Hacettepe University in terms of scientific publications within the scale of Turkey and is there any change over time? 2) In which fields and journals do the members of Hacettepe University make publications most frequently? 3) What is the tendency of co-authorship for Hacettepe University-addressed publications and is there any change in the number of authors over time? 4) What other institutions do the authors of Hacettepe University collaborate most frequently? 5) In which countries do the authors who most frequently collaborate with Hacettepe University work? 6) Who are the most productive Hacettepe University-addressed authors in the citation indexes? Besides answering these research questions, co-authorship networks and institutions that were collaborated with are visually demonstrated via CiteSpace, which is an open-access social network analysis software. These attempts of visualization, along with the evaluation of the publications that were produced by the universities, will serve as a data source for the studies that aim to build a publication policy.Türkiye’deki üniversiteler içinde Hacettepe Üniversitesi atıf dizinleri kapsamında en fazla ya-yına imza atan kurum olma özelliğine sahiptir. Bu çalışmada Hacettepe Üniversitesi’nin atıf dizinlerine ilk yayınının girdiği yıldan (1968) 2009 yılına kadar olan yayınları çeşitli bibliyo-metrik özellikleri açısından incelenmekte, elde edilen bibliyometrik veriler sosyal ağ analizi yöntemiyle değerlendirilmektedir. Disiplinlerarası bir çalışma alanı olan sosyal ağ analizi bir-çok farklı alanda sıklıkla kullanılan bir yöntemdir. Bu yöntem ile toplulukların yapısı incelen-mekte, ağ yapısı betimlenmekte, topluluklar arasında kolayca gözlemlenemeyen ilişkiler gör-selleştirilerek var olan bağlantılar modellenmeye çalışılmaktadır. Araştırma kapsamında yanıt aranan soruları şu şekilde sıralamak olanaklıdır: 1) Hacettepe Üniversitesi’nin yayın üretimi Türkiye ölçeğinde ne düzeydedir ve zamana göre herhangi bir değişim söz konusu mudur? 2) Hacettepe Üniversitesi mensupları en sık hangi alanlarda ve hangi dergilerde yayın faaliye-tinde bulunmaktadırlar? 3) Hacettepe Üniversitesi’ne ait yayınlarda ortaklaşa yayın yapma açısından eğilim nedir ve zaman içerisinde yazar sayılarında herhangi bir farklılık gözlenmek-te midir? 4) Hacettepe Üniversitesi’ndeki yazarların en sık işbirliği içerisinde bulunduğu ku-rumlar hangileridir? 5) Hacettepe Üniversitesi bünyesindeki yazarların en sık ortaklaşa yayın yaptığı yazarlar hangi ülkelerde görev yapmaktadır? 6) Atıf dizinleri kapsamındaki en verimli Hacettepeli yazarlar hangileridir? Çalışmada bir taraftan yukarıda sıralanan sorulara yanıtlar verilirken diğer taraftan ortak yazar ağları ve ortak yayın yapılan kurumlar CiteSpace adlı açık erişime sahip bir sosyal ağ analizi yazılımdan yararlanılarak görselleştirilmektedir. Hem bu tip görselleştirme çalışmaları hem de üniversitelerin ürettikleri yayınların değerlendirilmesi bilimsel yayın politikası oluşturma amaçlı çalışmalara veri kaynağı sağlayacaktır

The Impact of Turkey in The Library and Information Science

This paper investigates the contribution of Turkey to the world library and information science literature. In this study we investigate the bibliometric characteristics of 219 library and information science journal articles written by authors affiliated with Turkish institutions and indexed in the Social Sciences Citation Index (SSCI) between the years 1974-2013. The most preferred library and information science journals to publish articles for Turkey addressed authors are Information Processing & Management and Scientometrics. 159 of 219 articles of Turkey addressed library and information science articles were cited at least once by the publications in citation indexes. Total number of citations of Turkey addressed 159 articles was 1304. All of the contributions were written in English and one-third of them had single authorship. Turkey addressed library and information science articles have been cited by 69 different countries and in particular mostly by the United States of America, China and England. On the other hand the country self-citation was 27%

Effect of 38% silver diamine fluoride on fracture resistance of leucite reinforced feldspathic ceramic CAD/CAM class I inlay restorations

Introduction: Silver diamine fluoride (SDF) is a topical agent that has recently gained popularity for its ability to stop and prevent dental caries. Aim: The aim of this study was to evaluate the effect of SDF applied to class I cavities of extracted non-caries molar teeth on the fracture resistance of CAD/CAM block. Materials and methods: Twenty eight extracted noncarious molars were selected for the study. They were divided into two groups (n=14 per group). In each tooth, a diamond head was used to create Class I cavities that were 2 mm deep and 2 mm wide. The fracture strength test was carried out by applying a force at a speed of 5 mm/min, while continuously increasing the long axis of the tooth at the point corresponding to the central fossa. Results: SDF application did not have a statistically significant effect on fracture resistance in teeth restored with Class I cavities CAD/CAM blocks. The two groups did not differ statistically significantly according to the two-way ANOVA [mean fracture force (N) ± standard deviation: without SDF 1138.19±581.65 and with SDF 1067.93±555.65; p=0.712]. Conclusions: This study showed that SDF did not have either a positive or negative effect on the fracture resistance for restoration or easy application in cavities. Long-term clinical studies with different mechanical tests are needed for the safe use of SDF in pre-restoration cavities with CAD/CAM blocks

Collaboration of Turkish Scholars: Local or Global?

Collaboration patterns of scholars have been the subject of many studies. This paper investigates the collaboration patterns of the Turkish scholars’ publications within the citation indexes. Turkey’s contribution to the world’s scientifi c literature has increased signifi cantly during the recent years. It is important to understand the collaboration types in scholarly communication in order to derive a legitimate scientifi c publication policy in Turkey. In this context, the following research questions have been addressed: 1. Is the multiple authorship prevalent in the Turkish publications? 2. Does the collaboration rate change by year? 3. What is the distribution of collaboration types (intranational/international) authored by Turkish scholars? 4. Does the rate and type of collaboration diff er across the disciplines? 5. Which countries are the most important collaborative partners of Turkish scholars? Based on the analysis of fi ndings, we found that Turkish scholars generally collaborate intranationall

Nvis Hf Signal Propagation In Ionosphere Using Calculus Of Variations

Modeling Near Vertical Incidence Sounding (NVIS) High Frequency (HF) signal propagation in the ionosphere is important. Because, ionosondes which are special types of radars probing the ionosphere with certain HF frequencies (between 2 and 30 MHz), work mostly in NVIS mode (where elevation angle is between 89 and 90 degrees). In this work, we are going to propose a new method for NVIS wave propagation in the ionosphere by discretizing the NVIS wave propagation path into mediums in which the refractive index changes linearly, where we solve the ray propagation in each medium analytically using calculus of variations and use Snell's Law at medium changes. The main advantage of the proposed solution is the reduced computational complexity and time. This algorithm can be used to simulate and compare the behavior of vertical ionosondes together with other ray tracing algorithms. (C) 2018 Institute of Seismology, China Earthquake Administration, etc. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.WoSScopu