Atay, İrem | Kırmızıbekmez, Hasan | Yeşilada, Erdem | Gören, Ahmet Ceyhan

Other | 2015 | Turkish Journal of Chemistry39 ( 1 ) , pp.34 - 41

Abstract: A new nonglycosidic iridoid, sambulin B (1), was isolated from the methanol extract of Sambucus ebulus L. leaves along with a recently reported new nonglycosidic iridoid, 10-O-acetylpatrinoside aglycone (sambulin A) (2); 2 flavonoids, isorhamnetin-3-O-eta-D-glucopyranoside (3) and isorhamnetin-3-O-rutinoside (4); and a mixture of 2 flavonoids (5), quercetin-3-O-eta-D-glucopyranoside and quercetin-3-O-eta-D-galactopyranoside. Their structures were elucidated by 1-D and 2-D nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) experiments.

Saatçı, Gökhan Erkin | Tahralı, Necati

Other | 2003 | Havacılık ve Uzay Teknolojileri Dergisi1 ( 2 ) , pp.33 - 39

Daha önceden bilindiği üzere, malzemelerin Wohler eğrisini elde etmek oldukça güçtür. Ancak işletmelerde dinamik yüklemelere maruz makina parçalarının servis ömürlerini tayin edebilmek için birikimli hasar teorilerine ihtiyaç duyulmakta ve teorileri kullanabilmek içinse malzemelerin zorlandığı gerilmelerdeki maksimum ömür değerlerinin bilinmesi gerekmektedir. Bu ömür değerleri ise Wohler eğrilerinden okunmaktadır. Bu çalışmada Wohler eğrilerinden bağımsız olarak eşdeğer yorulma ömrünün hesaplanması amaçlanmıştır. Dolayısıyla birikimli hasar teorilerinin ihtiyaç duyduğu ömür değerleri, yorulma çatlağının artışını toplama prensibine d . . .ayanan ampirik bir ifadeden elde edilmiştir. Çalışmada öncelikle bu ampirik ifade tanıtılmış ve 1013. Ord. Ana. Tam. Fabrikasında üretilen GTD model 4X4 askeri aracın çeşitli değişken gerilmeler altında çalışan aktarma elemanının yorulma ömrü hesaplarında kullanılarak eşdeğer ömür hesabı yapılmıştır. As known before, obtaining Woehler diagrams of the materials are very difficult. But to predict the service life of machine elements that are subject to cyclic loads, the cumulative damage theories are needed, and to use the teories maximum life values at the stresses that the specimen is loaded must known. These values are being read from Woehler diagrams: In this study, it is aimed to calculate the equivalent fatigue life, independent from Woehler diagrams. Therefore life values that are needed for cumulative failure theories, are obtained from an emprical expression that is related to fatigue crack growth rate. First of all, this emprical expression is described and then it is used to calculate the equivalent life of the transmission component of "GTD model 4X4 military vehicle" that is being produced in "1013. Ord. Ana. Tarn. Fabrikası" which is working under several variable stresses Daha fazlası Daha az

İnce, Ahmet T. | Snook, Richard D. | Dawson, John B.

Other | 2000 | Turkish Journal of Chemistry24 ( 1 ) , pp.43 - 58

A study of inherent noise sources present in a purpose built flame atomic magneto-optic rotation (AMOR) spectrometer system was carried out with a view to identifying their sources. Two different optical configurations were employed, a crossed polariser and a 45° offset polariser configuration. The offset polariser configuration was operated in both an AMOR and atomic absorption (AA) mode for the noise measurements. Two main interference frequencies were found to occur in all the optical measurement modes. An interference flame feature frequency (15.5 Hz -39.0 Hz) which arose from an "organ-pipe" effect in the gas flow . . . through the flame cooling sheets. The second interference frequency (at 100 Hz) was thought, to arise due to modulation of the analytes magneto-optic properties due to ripple on the electromagnet d.c. power supply. Photon noise and fluctuation noise were found to be present as background noise. The fluctuation noise was dominant at. higher analyte concentrations. The characteristics and origins of fluctuation noise are discussed and investigated for each measurement mode. The noise spectra of the conventional AA measurements were compared with those of the contemporary AMOR measurements, to ascertain any differences in noise power spectra which may affect, the signal-to-noise ratio Daha fazlası Daha az

Aygün, Birol

Other | 2004 | Turkish Journal of Electrical Engineering and Computer Sciences12 ( 2 ) , pp.107 - 116

The importance of projects in software engineering courses is well known. Both synthetic and real-life projects have various advantages and disadvantages. Our aim was to create a framework where students can develop projects which reflect some of the complexities of real-life, involving many concurrent, interacting, asynchronous processes, each in a different stage of development, with wide temporal differences among them - some occurring- within millisconds of each other and others executing sporadically over much longer periods. In this project, which was carried out in different arrangements in several software engineering course . . .s in three universities, the students developed both the sub- and super-structures required, with varying degrees of success. The projects were performed in parallel with and subsequent to one-semester courses in software engineering. The development was performed in accordance with the principles established in the lectures. The sub-structure consists of a discrete-time event simulator and a message passing mechanism. It can support many different super-structures. The super-structure we created was an e-business community simulator where a manufacturer, its trading partners and the transactions among them were simulated. In this paper we summarize the project and our experiences during the development. A literature search for similar projects for software engineering education did not yield any hits. However several reported industrial projects for virtual supply chain management were examined. Our project on the other hand was tailored for implementation by student groups in one semester with the primary purpose of getting experience in complex, multi-group software development rather than immediate industrial use of the software Daha fazlası Daha az

İnce, T Ahmet

Other | 2001 | Turkish Journal of Chemistry25 ( 2 ) , pp.135 - 143

Analytical signals in an Atomic Magneto-Optic Rotation spectrometer are buried in noise at the limit of detection. The noisy analytical signals were analysed by carrying out mathematical correlation of their time domain waveforms. The noise components of signals were removed by auto-correlation to simplify the study. If noise interferes in analytical signals whose source is unclear, a cross-correlation of the output waveform with noise source may identify the source, e.g., mains frequencies and background radio signals. A cross-correlation will reveal whether the two signals are derived from the same source. This can also lead to an . . . improvement in the signal detection limit. Either of the two above situations can occur in studying analytical signals. In this study, both auto-and cross-correlation studies were carried out on analytical signals which had discrete noise sources present in their waveforms Daha fazlası Daha az

Saatçı, Gökhan Erkin | Tahralı, Necati

Other | 2003 | Havacılık ve Uzay Teknolojileri Dergisi1 ( 1 ) , pp.21 - 30

Malzemelerde oluşan yorulma hasarının incelenip önceden saptanabilmesi, yorulma kırılmalarını önleyebilmek için çok büyük önem kazanmaktadır. Yorulma konusundaki en önemli konu ise çeşitli değişken gerilmelere maruz kalan malzemelerin gösterdikleri birikimli hasarlardır. Bu çalışmada, çeşitli araştırmacılar tarafından ortaya konmuş birikimli hasar metotları sunulmuş ve bu metotlar 1013. Ord. Ana. Tam. Fabrikasında üretilen GTD model 4X4 askeri aracın çeşitli değişken gerilmeler altında çalışan aktarma elemanına uygulanmıştır. Her metodun kendine özgü kuralları bulunduğundan herbiri farklı sonuçlar vermiştir. Çalışmadaki amaç, pratik . . .te karşılaşılan çeşitli birikimli hasar durumlarında bulunan metotlardan hangisinin kullanılması gerektiğini saptamaktır. Formüllerde kullanılan çentik, yüzey düzgünlük, boyut faktörleri, gerilmelerin uygulanma yüzdeleri ve malzemenin mukavemet özellikleri, örnek gösterilen aracın aktarma organları üzerinde uygulanmış başka bir çalışmadan elde edilen sonuçlara göre alınmıştır. The prediction of fatigue failure in the materials has great importance in preventing of fatigue cracks. The most important thing in fatigue topic is the cumulative damage that can be seen in the materials subjected to several variable stresses. In this study, the cumulative fatigue failure methods that are created by several researchers, are represented and these methods are applied to the transmission component of "GTD model 4X4 military vehicle" that is being produced in "1013. Ord. Ana. Tam. Fabrikası" which is working under several variable stresses. Because of having special characteristics, each method gave different solutions. This study is aimed at the problem that is encountered in practice which is the choice of the method for the several different cumulative failure conditions. Notch, surface quality, dimension factors, stresses' applying percents and the material's strength properties that are used in the equations are taken from another study that is applied on this example vehicle's transmission elements Daha fazlası Daha az

Özkaya, Mert

Other | 2018 | Havacılık ve Uzay Teknolojileri Dergisi11 ( 2 ) , pp.119 - 133

In this paper, the existing 31 different UML-based software modelling languages have been analysed for anumber of requirements that are believed to be highly important for practitioners. These requirements areformal semantics, multiple viewpoints modelling, model analysis, code-generation, and modelling toolset.According to the analysis results, only the UWE, TTool, Pi-ADL languages support all those requirements. While21% of the languages offer general-purpose notation set, the rest offer domain-specific notation set and the topdomains of interest are the multi-agent, embedded, and real-time systems. 38% of the languages use UML’sp . . .rofiling mechanism for extending UML, 18% of the languages extend UML’s class diagram, and 13% of thelanguages extend UML’s state and sequence diagrams. 41% of the languages support the logical viewpoint and36% support the behaviour viewpoint – the rest of the viewpoints are rarely used. 58% of the languages aredefined formally and many of them are based on formal verification languages. 44% of the languages ignoremodel analysis. Among the rest, 25% of the languages support the exhaustive model checking and 14% supportthe analysis for well-formedness. Generating software code from software models and the modelling toolsupport are the least supported requirements by the UML-based languages. Bu makalede, mevcut 31 farklı UML-tabanlı yazılım modelleme dili yazılımcılar için önemli olan bir takımgereksinimler bakımından analiz edilmiştir. Bu gereksinimler, biçimsel semantik, çoklu bakış-açısı ilemodelleme, modellerin analizi, modellerden kod üretme, ve modelleme araçları desteği olarak belirlenmiştir.Analiz sonuçlarına göre, 31 farklı UML-tabanlı modelleme dili arasından sadece UWE, TTool, ve Pi-ADLdillerinin tüm belirtilen gereksinimleri karşılayabildiği gözlemlenmiştir. UML-tabanlı dillerin 21%’i genelamaçlı diller olarak belirlenmişken, geri kalanı ise alana özgü dillerdir ve en yaygın olan alanlar ise gömülüsistemler, çok etmenli sistemler, ve gerçek zamanlı sistemlerdir. UML-tabanlı dillerin 38%’i UML’in profilmekanizmasını kullanarak UML’i genişletirken, 18%’i UML’in sınıf diyagramını ve 13%’ü UML’in durum vesıra diyagramlarını genişletmektedirler. UML-tabanlı dillerin 41%’i mantıksal bakış açısını desteklerken,36%’sı da davranış bakış açısını desteklemektedir. Diğer bakış açıları (aynı anda kullanım, fiziksel, dağıtım, veoperasyonel gibi) pek destek görememektedir. UML-tabanlı dillerin 58%’inin semantiği biçimsel metotlarkullanılarak tanımlandığı belirlenmiştir. Dillerin 44%’ü modellerin analizini desteklememektedir. Geri kalanının25%’i ise kapsamlı model sınaması ile modellerin analizini desteklerken, 14%’ü ise dillerin biçim kurallarınagöre analizini desteklemektedirler. Yazılım modellerinin koda dönüştürülmesi hemen hemen hiçbir UML-tabanlıdil tarafından destek görmemektedir. Yine aynı şekilde, dillerin hemen hemen hiçbiri modelleme araçları iledesteklenmemektedir Daha fazlası Daha az

Kalender, Murat | Korkmaz, Emin Erkan

Other | 2017 | Turkish Journal of Electrical Engineering and Computer Sciences25 ( 3 ) , pp.2388 - 2398

Entity-linking systems link noun phrase mentions in a text to their corresponding knowledge base entities in order to enrich a text with metadata. Wikipedia is a popular and comprehensive knowledge base that is widely used in entity-linking systems. However, long-tail entities are not popular enough to have their own Wikipedia articles. Therefore, a knowledge base created by using Wikipedia entities would be limited to only popular entities. In order to overcome the knowledge base coverage limitation of Wikipedia-based entity-linking systems, this paper presents an entity-discovery system that can detect semantic types of entities t . . .hat are not defined in Wikipedia. The effectiveness of the proposed system was validated empirically through the use of generated data sets for the Turkish language. The experimental results show that, in terms of accuracy, our system performs competitively in comparison to the previous methods in the literature. Its high performance is achieved through a method that learns word embeddings for candidate entitie Daha fazlası Daha az