Bilgisayar Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/253
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Article Remote laboratory development as an action research: A case study(2012) Çağıltay, Nergiz Erçil; Tokdemir, Gül; Aydın, Elif; Kara, AliThis work presents a case study about how action research (AR) has been conducted in developing a real-life educational system. An explanation is given of the modified implementation of the classical AR methodology, based on the requirements of a remote laboratory system developed for the vocational training of students in higher education. This study reports a successful implementation of AR stages which established for the development process of a remote laboratory system along with the design of several research questions explored in each step of the system development process. It is believed that the outcomes of the study will help AR implementers to organize their research objectives, more appropriately, by addressing the organizational problems. The results of this study are also expected to guide the AR implementers to better integrate their research in solving domain specific practical problemsArticle Topic Model Implementation To Find Related Documents In Corporate Archives In Real Life: “A Case Scenario On Knowledge Retrieval”(2013) Medeni, İhsan Tolga; Medeni, Tunç DurmuşToday’s organizations were mostly built over their documents. These documents are very crucial sources of knowledge. Even they know the existence of these documents, most of the time, it is nearly impossible to extract captive knowledge inside. In these conditions, organizations choose re-prepare same document again rather than finding proper documents in the archives. On the other hand, finding these documents would save precious time and decrease redundancy of the work. Topic model idea basically focuses on extraction of knowledge from these types of documents. In this study, our aim is to give a summary of Topic Model research and try to explain latest model concept over an imaginary case scenarioArticle Open Access Awareness in Scholarly Communication: The Case of Çankaya University(2011) Darvish, HamidThe Scholarly Communications processes consist of collecting and analyzing of data—including published information—through its transformation into publications or other output, and its usage or preservation by other users. In this respect, researchers, publishers, libraries and data managers play important roles in applying and implementing of scholarly communications.1 Conventionally, the flow of scientific papers’ publication starts by a research activity followed by manuscript submission, peer review, publishing cost by publisher and so on. Whereas, in open access publication, after peer review the cost of publication is paid by the author (See, Figure 1).Article Low-diameter topic-based pub/sub overlay Network Construction with minimum–maximum node Degree(PeerJ Inc., 2021) Yumusak, Semih; Layazali, Sina; Öztoprak, Kasım; Hassanpour, RezaIn the construction of effective and scalable overlay networks, publish/subscribe (pub/sub) network designers prefer to keep the diameter and maximum node degree of the network low. However, existing algorithms are not capable of simultaneously decreasing the maximum node degree and the network diameter. To address this issue in an overlay network with various topics, we present herein a heuristic algorithm, called the constant-diameter minimum–maximum degree (CD-MAX), which decreases the maximum node degree and maintains the diameter of the overlay network at two as the highest. The proposed algorithm based on the greedy merge algorithm selects the node with the minimum number of neighbors. The output of the CD-MAX algorithm is enhanced by applying a refinement stage through the CD-MAX-Ref algorithm, which further improves the maximum node degrees. The numerical results of the algorithm simulation indicate that the CD-MAX and CD-MAX-Ref algorithms improve the maximum node-degree by up to 64% and run up to four times faster than similar algorithms.Article İmge İçine Bilgi Gizlemede Kullanılan LSB Yöntemlerinin Karşılaştırması(2013) Saran, Nurdan; Olcay, CemDijital imgeleri temel olarak kayıplı sıkı¸stırılmı¸s tipte olanlar, sıkı¸stırılmamı¸slar ve kayıpsız sıkı¸stırılmı¸slar olarak ¨u¸ce ayırabiliriz. Sıkı¸stırılmamı¸s ve kayıpsız sıkı¸stırılmı¸s imgelerde bilgi gizlemek i¸cin en ¸cok kullanılan y¨ontem, imgenin son bitlerinin mesajın bitleri ile de˘gi¸stirilmesi y¨ontemidir. Son bitlerin de˘gi¸simi genellikle imgede g¨ozle g¨or¨ulebilir bir de˘gi¸sikli˘ge sebep olmamaktadır. Ort¨u imgedeki piksellerin son bitlerinin de˘gi¸simi ile ¨ veri gizleme y¨ontemlerini her renk kanalında 1 bit yada daha fazla veri gizleyenler ve birden ¸cok renk kanalında renk kanalı sayısından daha az miktarda veri gizleyenler olarak ikiye ayırabiliriz. Bu ¸calı¸smada en ¨onemsiz bite (least significant bit-LSB) gizleme y¨ontemlerinden yer de˘gi¸stirme [1], e¸sle¸stirme [2], e¸sle¸stirmenin geli¸stirilmi¸s bir hali olan Chan’ın algoritması [3], 2/3 verimli g¨omme [4], Hamming kodlarını kullanılarakArticle Did satellite imagery supersede aerial imagery? A perspective from 3D geopositioning accuracy(2016) Yilmaz, Altan; Erdogan, Mustafa; Maraş, Hadi Hakan; Aktuğ, Bahadır; Maraş, Süleyman SırrıIn this study, the geometric accuracy comparison of aerial photos and WorldView-2 satellite stereo image data is evaluated with the different number and the distribution of the ground control points (GCPs) on the basis of large scale map production. Also, the current situation of rivalry between airborne and satelliteborne imagery was mentioned. The geometric accuracy of Microsoft UltraCam X 45 cm ground sampling distance (GSD) aerial imagery and WorldView-2 data both with and without GCPs are also separately analyzed. The aerial photos without any GCP by only using global navigation satellite system (GNSS) and inertial measurement unit (IMU) data with tie points give an accuracy of +/- 1.17 m in planimetry and +/- 0.71 m in vertical that means nearly two times better accuracy than the rational polynomial coefficient (RPC) of stereo WorldView-2. Using one GCP affects the accuracies of aerial photos and WorldView-2 in different ways. While this situation distorts the aerial photo block, it corrects the shift effect of RPC in WorldView-2 and increases the accuracy. By using four or more GCPs, 1/2 pixel (similar to 0.23 m) accuracy in aerial photos and 1 pixel (similar to 0.50 m) accuracy in WorldView-2 can be achieved in horizontal. In vertical, aerial photos have 1 pixel (similar to 0.55 m) and WorldView-2 has 1.5 pixels (similar to 0.85 m) accuracy. These results show that Worldview-2 imagery can be used in the production of class I 1: 5000 scale maps according to the ASPRS Accuracy Standards for Digital Geospatial Data in terms of geometric accuracy. It is concluded that the rivalry between aerial and satellite imagery will continue for some time in the future.Article An Exploratory Study to Assess Digital Map Zoom/Pan/Rotate Methods with HoloLens(2018) Kılınç, İsmail; Yılmaz, MuratGeographical map display plays an important part of a GIS (GeographicalInformation System). The usability of a map display is certainly depends on how easilyuser navigates through spatial data and selects features on it. Currently, desktop computerbased GIS applications uses mouse movements, buttons and scroll for a set of functionssuch as zoom, pan and rotate. However currently Hololens supports only gaze, air tapgesture and voice commands as an input. Although the functionality looks simple, it ischallenging to find optimal solution by using input devices for those functions even whilecreating in a desktop application. This study aims to assess an optimal way to enable thesefunctions on hologram maps by investigating its validity and usability.Article Behavior Analysis Of Routing Protocols For A Health Decision Support System(2014) Alyeksyeyenkov, Yuriy; Abdullah, Mohammed Najm; Tareq Nafea, MustafaMobile ad-hoc network (MANET) is an infrastructure less network, that is a collection of mobile devices connected together without centralized infrastructure that can be configured at any time and any where, it gives the network dynamic topology. The most important thing in MANETs is a routing protocol. MANETs have a three major routing protocols proactive, reactive and hybrid. In this work, the performance of reactive routing protocol Ad hoc on demand Distance Vector (AODV) and proactive routing protocol Destination Sequenced Distance Vector (DSDV) for a health decision support system (HDSS) were evaluated. The major goal of this work is to analyze the performance of well-known MANETs routing protocol in mobility case under low, medium and high density scenario. Hence it becomes important to study the performance of these routing protocols. The performance is analyzed with respect to Average End-to-End Delay, drop packets, Packet Delivery ratio (PDR) and Throughput. Simulation results verify that AODV gives better performance as compared to DSDV.Conference Object Kişisel Sağlık Kaydı Sistemleri Kullanılabilirlik Durum Çalışması(2015) Gökay, Gonca; Ercil, Yavuz; Tokdemir, Gül; Ercil Çağıltay, NergizYeni teknolojilerle birlikte sağlk sektöründe de süreçlerin iyileştirilmesi ve sağlk hizmetlerinin kalitesinin artrlmasna yönelik çalşmalar her geçen gün artmaktadr. Bu alanda yaplan çalşmalar sonucunda önceliklerin bütünleşik ve paylaşlabilen sağlk ve kişiye özel uygulamalar adreslemesi gerektiği görülmüştür. Bu uygulamalarn temel yaptaş hasta verilerinin kullanlmas yoluyla hzl ve doğru teşhis ve tedavi için yeni yöntemlerin geliştirilmesidir. Bu bağlamda kişilerin sağlkl ve hasta olduklar durumlarda sağlk durumlar ile ilgili tutacaklar verilerin önemi büyüktür. Dünyada ve ülkemizde sağlk hizmetlerinin iyileştirilmesi amacyla vatandaşlarn bu konuda bilincinin artrlmas giderek önem kazanmakta ve bu konuda ciddi çalşmalar yürütülmektedir. Bu kapsamda bireyin kendi sağlğ ile ilgili takipleri yapmak amacyla daha aktif bir rol almas ön plana çkmaktadr. Bu çalşmada Microsoft Health Vault olarak isimlendirilen ve kişisel sağlk verilerinin tutulmasna yönelik olarak geliştirilmiş olan sisteminin kullanlabilirlik çalşmas yaplmş ve sonuçlar tartşlmştr.Article Residual Lsf Vector Quantization Using Arma Prediction(2016) Özaydın, SelmaThe residual LSF vector quantization yields bit rate reduction in the vocoders. In this work, a residual LSF vector quantization obtained from Auto Regressive Moving Average (ARMA) prediction is proposed for designing codebooks at very low bit rates. This residual quantization method is applied to multi stage vector quantization method and codebooks are designed. For each codebook, the effectiveness and quality are investigated by calculating the spectral distortion and outliers. The proposed quantization method reduced the distortion without any additional complexity.