Bilgisayar Mühendisliği Bölümü

Permanent URI for this communityhttps://hdl.handle.net/20.500.12416/13

Browse

Now showing 1 - 4 of 4

Classification of Linked Data Sources Using Semantic Scoring
(Ieice-inst Electronics information Communication Engineers, 2018) Dogdu, Erdogan; Kodaz, Halife; Yumusak, Semih
Linked data sets are created using semantic Web technologies and they are usually big and the number of such datasets is growing. The query execution is therefore costly, and knowing the content of data in such datasets should help in targeted querying. Our aim in this paper is to classify linked data sets by their knowledge content. Earlier projects such as LOD Cloud, LODStats, and SPARQLES analyze linked data sources in terms of content, availability and infrastructure. In these projects, linked data sets are classified and tagged principally using VoID vocabulary and analyzed according to their content, availability and infrastructure. Although all linked data sources listed in these projects appear to be classified or tagged, there are a limited number of studies on automated tagging and classification of newly arriving linked data sets. Here, we focus on automated classification of linked data sets using semantic scoring methods. We have collected the SPARQL endpoints of 1,328 unique linked datasets from Datahub, LOD Cloud, LODStats, SPARQLES, and SpEnD projects. We have then queried textual descriptions of resources in these data sets using their rdfs: comment and rdfs: label property values. We analyzed these texts in a similar manner with document analysis techniques by assuming every SPARQL endpoint as a separate document. In this regard, we have used WordNet semantic relations library combined with an adapted term frequency-inverted document frequency (tfidf) analysis on the words and their semantic neighbours. In WordNet database, we have extracted information about comment/label objects in linked data sources by using hypernym, hyponym, homonym, meronym, region, topic and usage semantic relations. We obtained some significant results on hypernym and topic semantic relations; we can find words that identify data sets and this can be used in automatic classification and tagging of linked data sources. By using these words, we experimented different classifiers with different scoring methods, which results in better classification accuracy results.
Citation - WoS: 31
Density Functional Study of Physical and Chemical Properties of Nano Size Boron Clusters: Bn (n=13-20)
(Chinese Physical Soc, 2009) Ozdogan, Cem; Guvenc, Ziya B.; Atis, Murat
Boron is an element that has ability to build strong and highly directional bonds with boron itself. As a result, boron atoms form diverse structural motifs, ultimately can yield distinct nano structures, such as planar, quasi-planar, convex, cage, open-cage, tubular, spherical., ring, dome-like, shell, capsule, and so on, i.e., it can take almost any shape. Therefore, a deep understanding of the physical and chemical properties becomes important in boron cluster chemistry. Electronic and geometric structures, total and binding energies, harmonic frequencies, point symmetries, charge distributions, dipole moments, chemical bondings and the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps of neutral B-n (n=13-20) clusters have been investigated by, density functional theory (DFT), B3LYP with 6-311++G(d,p) basis set. Furthermore, the first and the second energy differences are used to obtain the most stable sizes. We have observed that almost all physical properties are size dependent, and double-ring tubular form of B-20 has the highest binding energy per atom. The icosahedral structure with an inside atom is found as impossible as a stable structure for the size thirteen. This structure transforms to an open-cage form. The structural transition from two-dimensional to three-dimensional is found at the size of 20 and consistent with the literature. The calculated charges by the Mulliken analysis show that there is a symmetry pattern with respect to the x-z and y-z planes for the charge distributions. The unusual planar stability of the boron clusters may be explained by the delocalized pi and sigma bonding characteristic together with the existence of the multicentered bonding. The results have been compared to available studies in the literature.
Citation - WoS: 2
Citation - Scopus: 2
Improvement of Dwt-Svd With Curve Fitting and Robust Regression: an Application To Astronomy Images
(Kaunas Univ Technology, 2016) Elbasi, Ersin; Karadeniz, Talha
DWT-SVD is a frequency domain based eigenanalysis watermarking technique. In this work, we improve this method by exploring the relationship between the cover image's DWT singular values and those of the watermark. We show that, via the usage of curve fitting and robust regression, it is possible to achieve accurate results. We also demonstrate that the improved scheme is suitable for the watermarking of astronomy images. In addition to encoding and decoding examples, statistical results on stealth and robustness are deduced from the experiments so that the clear advance can be observed. Quality of the watermark is measured by testing against various attack types.
Citation - WoS: 25
Citation - Scopus: 31
Supporting Foreign Language Vocabulary Learning Through Multimedia Messages Via Mobile Phones
(Hacettepe Univ, 2010) Saran, Murat; Saran, Murat; Seferoglu, Goelge; Bilgisayar Mühendisliği
This study explored the effectiveness of mobile learning in foreign language education. With this purpose, instructional materials to be delivered through mobile phones operated in second generation GSM technology in order to improve English language learners' vocabulary acquisition were developed. The multimedia messages in this study allowed students to see the definitions of words, example sentences, related visual representations, and pronunciations. After students finished reading multimedia messages, interactive short message service (SMS) quizzes for testing their learning were sent. In addition, the study examined students' tendencies in using MMS in their second language vocabulary study and explored the opinions of the students toward the use of mobile phones for instructional purposes. The findings of this study suggest some important points to consider while creating MMS content and a SMS quiz system for educational purposes.

Browse

Browsing Bilgisayar Mühendisliği Bölümü by WoS Q "Q4"