TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7149

Browse

Filters

2007 - 200922010 - 202019

Settings

Publisher: search.filters.publisher.Türkiye Klinikleri Journal of Medical SciencesScopus Q: search.filters.scopusQuartile.Q2

Search Results

Now showing 1 - 10 of 21
  • Article
    Citation - WoS: 2
    Citation - Scopus: 1
    Mutant Selection by Using Fourier Expansion
    (Türkiye Klinikleri Journal of Medical Sciences, 2020) Takan, Savaş; Ayav, Tolga
    Mutation analysis is a widely used technique to evaluate the effectiveness of test cases in both hardware and software testing. The original model is mutated systematically under certain fault assumptions and test cases are checked against the mutants created to see whether the test cases can detect the faults or not. Mutation analysis is usually a computationally intensive task, particularly in finite state machine (FSM) testing due to a possibly huge amount of mutants. Random selection could be a practical reduction method under the assumption that each mutant is identical in terms of the probability of occurrence of its associating fault. The present study proposes a mutant selection method based on Fourier analysis of Boolean functions. Fourier helps to identify the most effective transitions on the output so that the mutants related to those transitions can be selected. Such mutants are considered more important since they are more likely to be killed. To evaluate the method, test cases are generated by the well-known W method, which has the capability of detecting every potential fault. The original and reduced sets of mutants are compared with respect to their importance values. Evaluations show that the mutants selected by the proposed technique are more effective, which reduces the cost of mutation analysis without sacrificing the performance of the mutation analysis.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 7
    Fast Texture Classification of Denoised Sar Image Patches Using Glcm on Spark
    (Türkiye Klinikleri Journal of Medical Sciences, 2020) Özcan, Caner; Ersoy, Okan; Oğul, İskender Ülgen
    Classification of a synthetic aperture radar (SAR) image is an essential process for SAR image analysis and interpretation. Recent advances in imaging technologies have allowed data sizes to grow, and a large number of applications in many areas have been generated. However, analysis of high-resolution SAR images, such as classification, is a time-consuming process and high-speed algorithms are needed. In this study, classification of high-speed denoised SAR image patches by using Apache Spark clustering framework is presented. Spark is preferred due to its powerful open-source cluster-computing framework with fast, easy-to-use, and in-memory analytics. Classification of SAR images is realized on patch level by using the supervised learning algorithms embedded in the Spark machine learning library. The feature vectors used as the classifier input are obtained using gray-level cooccurrence matrix which is chosen to quantitatively evaluate textural parameters and representations. SAR image patches used to construct the feature vectors are first applied to the noise reduction algorithm to obtain a more accurate classification accuracy. Experimental studies were carried out using naive Bayes, decision tree, and random forest algorithms to provide comparative results, and significant accuracies were achieved. The results were also compared with a state-of-the-art deep learning method. TerraSAR-X images of high-resolution real-world SAR images were used as data.
  • Article
    Estimating Spatiotemporal Focus of Documents Using Entropy With Pmi
    (Türkiye Klinikleri Journal of Medical Sciences, 2020) Yaşar, Damla; Tekir, Selma
    Many text documents are spatiotemporal in nature, i.e. contents of a document can be mapped to a specific time period or location. For example, a news article about the French Revolution can be mapped to year 1789 as time and France as place. Identifying this time period and location associated with the document can be useful for various downstream applications such as document reasoning or spatiotemporal information retrieval. In this paper, temporal entropy with pointwise mutual information (PMI) is proposed to estimate the temporal focus of a document. PMI is used to measure the association of words with time expressions. Moreover, a word’s temporal entropy is considered as a weight to its association with a time point and a single time point with the highest overall score is chosen as the focus time of a document. The proposed method is generic in the sense that it can also be applied for spatial focus estimation of documents. In the case of spatial entropy with PMI, PMI is used to calculate the association between words and place entities. The effectiveness of our proposed methods for spatiotemporal focus estimation is evaluated on diverse datasets of text documents. The experimental evaluation confirms the superiority of our proposed temporal and spatial focus estimation methods.
  • Article
    Citation - Scopus: 1
    Reconstruction of Geometrical and Reflection Properties of Surfaces by Using Structured Light Imaging Technique
    (Türkiye Klinikleri Journal of Medical Sciences, 2018) Ozan, Şükrü; Gümüştekin, Şevket
    When a robust and dense surface reconstruction is aimed, structured light imaging techniques are usually much appreciated. In this paper we propose a method to reconstruct both geometrical and reflective properties of surfaces by using structured light imaging. We use a technique where a camera and a projector are both treated as viewing devices. They are calibrated in the same manner. Each visible point can be correctly located on both image planes without solving a correspondence problem; hence, a dense reconstruction can be obtained. Since both the camera and the projector are explicitly calibrated, lighting and viewing directions can be identified for each surface point. It is also possible to measure reflected radiance by using high dynamic range (HDR) images for each surface point. The lighting and viewing directions that are known after calibration are combined with the reflected radiance and the incoming irradiance measurements to determine the bidirectional reflectance distribution function (BRDF) values of the material at the reconstructed surface points. We illustrate the reconstruction of surface reflection properties of sample surfaces by fitting the Phong BRDF model to the BRDF measurements.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Elimination of Useless Images From Raw Camera-Trap Data
    (Türkiye Klinikleri Journal of Medical Sciences, 2019) Tekeli, Ulaş; Baştanlar, Yalın
    Camera-traps are motion triggered cameras that are used to observe animals in nature. The number of images collected from camera-traps has increased significantly with the widening use of camera-traps thanks to advances in digital technology. A great workload is required for wild-life researchers to group and label these images. We propose a system to decrease the amount of time spent by the researchers by eliminating useless images from raw camera-trap data. These images are too bright, too dark, blurred, or they contain no animals To eliminate bright, dark, and blurred images we employ techniques based on image histograms and fast Fourier transform. To eliminate the images without animals, we propose a system combining convolutional neural networks and background subtraction. We experimentally show that the proposed approach keeps 99% of photos with animals while eliminating more than 50% of photos without animals. We also present a software prototype that employs developed algorithms to eliminate useless images.
  • Article
    Citation - WoS: 2
    Privacy Issues in Post Dissemination on Facebook
    (Türkiye Klinikleri Journal of Medical Sciences, 2019) Sayın, Burcu; Şahin, Serap; Kogias, Dimitrios G.; Patrikakis, Charalampos Z.
    With social networks (SNs) being populated by a still increasing numbers of people who take advantage of the communication and collaboration capabilities that they offer, the probability of the exposure of people's personal moments to a wider than expected audience is also increasing. By studying the functionalities and characteristics that modern SNs offer, along with the people's habits and common behaviors in them, it is easy to understand that several privacy risks may exist, many of which people may be unaware of. In this paper, we focus on users' interactions with posts in a social network (SN), using Facebook as our research domain, and we emphasize some privacy leakages currently existing in Facebook's privacy policy. We also propose a solution to detected privacy issues, featuring a reference implementation of a tool based on a simulation, which visualizes the effect of potential privacy risks on Facebook and directs users to control their privacy. The proposed and simulated tool allows a post owner to observe the spreading area of his or her post depending on the selected privacy settings. Moreover, it provides preliminary feedback for all Facebook users that have interacted with this post, to make them aware of the possible privacy changes, aiming to give them a chance to protect the privacy of their interaction on this post by deleting it when an unwanted privacy change takes place. Finally, an online survey to increase privacy awareness in Facebook usage with over 500 volunteer participants has illuminated the need for such a tool or solution.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 10
    Performance Evaluation of Webrtc-Based Online Consultation Platform
    (Türkiye Klinikleri Journal of Medical Sciences, 2019) Tarım, Ergün Alperay; Tekin, Hüseyin Cumhur
    Information technologies give patients the opportunity to communicate with medical professionals remotely. Telemedicine uses these technologies to provide advanced healthcare and medical services. We present a medical online consultation application based on Web Real-Time Communications (WebRTC) technology enabling chat, audio, and video calls. Communication architecture and protocols of the application are explained in detail. Additionally, the user interface of the application is shown via performed calls. The application is tested and evaluated on different network connections (3G, 4G, local, and DSL) and different browsers and mobile operating systems (Android, Chrome, Firefox, Internet Explorer, iOS, Opera, Safari). During calls, communication quality parameters such as round-trip time (RTT) and packet loss, obtained via the WebRTC application programming interface, are analyzed. 3G, 4G, and local connections show low packet losses (<1%). Packet losses are high (>1%) in Android, Chrome, iOS, Opera, and Safari for DSL connection, but RTT values are low (<100 ms) in all different conditions excluding iOS. In the presented application, RTT and packet loss remain lower than 100 ms and 1%, respectively, in various scenarios, indicating good communication quality. RTT and packet loss are related to total time and hang time parameters, which describe the necessary time to establish and to end a call. It is shown that communication quality of the application can simply be measured by analyzing the total time parameter. This enables predictable information for communication quality for WebRTC-based applications without continuously monitoring RTT and packet loss for the first time.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Quantification of Resistive Wall Instability for Particle Accelerator Machines
    (Türkiye Klinikleri Journal of Medical Sciences, 2019) Yaman, Fatih
    The aim of this study is to quantify longitudinal resistive wall impedances, corresponding wake functions, and wake potentials for different accelerator machines of interest. Accurate calculations of wake potentials by particle-in-cell codes are extremely difficult for the investigated parameters; therefore, we use an analytical approach and consider large domains with fine discretization for the required numerical integrations. The semianalytical wake potential computations are benchmarked against numerical general purpose 2D/3D Maxwell solver software codes and a different analytical approach for a certain set of parameters. We report examples to illustrate limitations of wake potential estimations from coupling impedances, and computations for the machines using realistic beam parameters and machine conditions. A numerical example where the aim is to find the wake potential of the machine from the 5% noisy impedance data is given.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Investigating the Experimental Limits of the Brewster’s Angle Method
    (Türkiye Klinikleri Journal of Medical Sciences, 2018) Sümer, Can; Kuştepeli, Alp; Dinleyici, Mehmet Salih
    We present the method, analysis, and experimental results of the Brewster’s angle method commonly used for determining the refractive indices of optical films. We show the significance of the intersection of reflectance curves, in that the necessity for substrate refractive index and film layer thickness knowledge are both eliminated. We present the conditions for the existence of the second intersection of reflectance curves and introduce a method for determining the refractive index of the substrate layer by using the angular information alone. Analytical results reveal impressive practical sensitivity and accuracy limits for the method, where the experimental results also support the theoretical analysis.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Characterization of the Beta1 Gene, Which Might Play a Role in Beta Vulgaris Subsp. Maritima Salt Tolerance
    (Türkiye Klinikleri Journal of Medical Sciences, 2017) Uysal, Özge; Çakıroğlu, Çiğdem; Koç, Ahmet; Karakaya, Hüseyin Çağlar
    Salinity stress has a negative impact on plant growth, which affects homeostasis and productivity. The uptake of nonessential salt ions changes the osmotic balance of the cell and causes dehydration. Higher plants develop salt tolerance mechanisms to avoid dehydration. Sea beet (Beta vulgaris subsp. maritima) is a halophytic ancestor of cultivated sugar beet that displays salt stress tolerance. In this study, we screened a B. vulgaris subsp. maritima cDNA library in Saccharomyces cerevisiae strain Ab11c (ena1Δ, nha1/4Δ, nhx1Δ), which is deficient in sodium transport, to find sodium-detoxifying genes. We identified a cDNA construct, named BETA1, providing salt tolerance to yeast cells. This gene had no previously described function. Intracellular sodium measurements demonstrated no significant differences between yeast cells expressing BETA1 or a sham vector, suggesting that sodium was not effluxed in BETA1-expressing cells. Transcriptionally, BETA1 mRNA levels were induced immediately in leaves and later in the root system in response to the salt stress. Our results suggest that the BETA1 gene is part of the salt tolerance network in B. vulgaris subsp. maritima.