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Öğe Assessment of environmental factors affecting software reliability: a survey study(Tubitak Scientific & Technological Research Council Turkey, 2020) Ozcan, Alper; Catal, Cagatay; Togay, Cengiz; Tekinerdogan, Bedir; Donmez, EmrahCurrently, many systems depend on software, and software reliability as such has become one of the key challenges. Several studies have been carried out that focus on the impact of external environmental factors that impact software reliability. These studies, however, were all carried out in the same geographical context. Given the rapid developments in software engineering, this study aims to identify and reinvestigate the environmental factors that impact software reliability by also considering a different context. The environmental factors that have an impact on software reliability as reported in earlier studies have been analyzed and synthesized. Subsequently, a survey study is conducted to analyze the impact of 32 environmental factors from the perspective of multiple stakeholders. Several statistical analysis methods were applied for the analysis. Data were collected from 24 organizations and 70 software professionals. Most factors shown in top 10 lists of previous studies remain in the top 10 in our study, but their order is different. Testing coverage is now the most significant factor and testing effort is considered as the second most significant factor. The environmental factors defined previously retain their impact. The ordering of the importance of the environmental factors has changed though.Öğe Central nervous system thrombosis in pediatric acute lymphoblastic leukemia in Turkey: A multicenter study(Wiley, 2023) Guzelkucuk, Zeliha; Karapinar, Deniz Yilmaz; Gelen, Sema Aylan; Tokgoz, Huseyin; Ozcan, Alper; Ay, Yilmaz; Bahadir, AysenurBackgroundIn patients with acute lymphoblastic leukemia (ALL), the risk of thromboembolism increases due to hemostatic changes secondary to the primary disease and due to treatment-related factors. In this multicenter study, we aimed to research the frequency of central nervous system (CNS) thrombosis occurring during treatment, hereditary and acquired risk factors, clinical and laboratory features of patients with thrombosis, treatment approaches, and thrombosis-related mortality and morbidity rates in pediatric ALL patients. ProcedurePediatric patients who developed CNS thrombosis during ALL treatment from 2010 to 2021 were analyzed retrospectively in 25 different Pediatric Hematology Oncology centers in Turkiye. The demographic characteristics of the patients, symptoms associated with thrombosis, the stage of the leukemia treatment during thrombosis, the anticoagulant therapy applied for thrombosis, and the final status of the patients recorded through electronic medical records were determined. ResultsData from 70 patients with CNS thrombosis during treatment, out of 3968 pediatric patients with ALL, were reviewed. The incidence of CNS thrombosis was 1.8% (venous: 1.5 %; arterial: 0.03%). Among patients with CNS thrombosis, 47 had the event in the first 2 months. Low molecular weight heparin (LMWH) was the most commonly used treatment with a median of 6 months (min-max: 3-28 months). No treatment-related complications occurred. Chronic thrombosis findings occurred in four patients (6%). In five (7%) patients who developed cerebral vein thrombosis, neurological sequelae (epilepsy and neurological deficit) remained. One patient died related to thrombosis, and the mortality rate was 1.4%. ConclusionCerebral venous thrombosis and, less frequently, cerebral arterial thrombosis may develop in patients with ALL. The incidence of CNS thrombosis is higher during induction therapy than during other courses of treatment. Therefore, patients receiving induction therapy should be monitored carefully for clinical findings suggestive of CNS thrombosis.Öğe A hybrid DNN-LSTM model for detecting phishing URLs(Springer London Ltd, 2023) Ozcan, Alper; Catal, Cagatay; Donmez, Emrah; Senturk, BehcetPhishing is an attack targeting to imitate the official websites of corporations such as banks, e-commerce, financial institutions, and governmental institutions. Phishing websites aim to access and retrieve users' important information such as personal identification, social security number, password, e-mail, credit card, and other account information. Several anti-phishing techniques have been developed to cope with the increasing number of phishing attacks so far. Machine learning and particularly, deep learning algorithms are nowadays the most crucial techniques used to detect and prevent phishing attacks because of their strong learning abilities on massive datasets and their state-of-the-art results in many classification problems. Previously, two types of feature extraction techniques [i.e., character embedding-based and manual natural language processing (NLP) feature extraction] were used in isolation. However, researchers did not consolidate these features and therefore, the performance was not remarkable. Unlike previous works, our study presented an approach that utilizes both feature extraction techniques. We discussed how to combine these feature extraction techniques to fully utilize from the available data. This paper proposes hybrid deep learning models based on long short-term memory and deep neural network algorithms for detecting phishing uniform resource locator and evaluates the performance of the models on phishing datasets. The proposed hybrid deep learning models utilize both character embedding and NLP features, thereby simultaneously exploiting deep connections between characters and revealing NLP-based high-level connections. Experimental results showed that the proposed models achieve superior performance than the other phishing detection models in terms of accuracy metric.Öğe Hydrothorax caused by catheter malposition misdiagnosed via using plain radiography(2017) Ergul, Ayse Betul; Ozcan, Alper; Altuner Torun, YaseminWe report the case of a child with hydrothorax caused by the misidentification of catheter malposition using plain radiography. A 9-month-old girl underwent central venous catheterization via the right subclavian vein. Catheter tip was evaluated mistakenly as in the right atrium by plain radiography. The catheter was retracted 2 cm and 1/3 normal saline infusion was initiated at 15 ml/hr. The patient became hypoxemic at the 20th hour of fluid infusion. On radiography, the right lung was completely opaque and the catheter tip was positioned in the right lung. Bedside sonography revealed a massive pleural effusion in the right lung and the catheter tip in the right pleural space. The catheter was removed and the pleural effusion was drained via chest tube. The location of the catheter tip should be determined by an accurate technique before infusing fluid. Plain radiography can be misleading for the detection of malposition.Öğe Inherited prothrombotic risk factors in children with hereditary angioedema(2019) Cansever, Murat; Ozcan, Alper; Ozkul, Yusuf; Patiroglu, TurkanAim: Hereditary angioedema is characterized with recurrent mucocutaneous angioedema, abdominal pain, edema of larynx and extremities. Dermal vascular thrombosis and systemic coagulation may occur in patients with hereditary angioedema due to inhibition of activated factor XII, thrombin and plasmin. Aim of this study was to screen patients with HAE for prothrombotic genetic risk factors before treatment.Material and Methods: Ten patients with hereditary angioedema who were followed up at our clinic were included in our study. The type and frequency of attack, use of prophylaxis and family history of hereditary angioedema were questioned and prothrombotic risk factors were studied.Results: Among the 10 included patients, five of them were male (50%) and five were female (50%). Four patients had abdominal edema (40%), four patients had edema of hands, feet and face (40%). One patient (10%) had heterozygous factor V G1691A mutation, another one had also heterozygous protrombin G20210A mutation. The heterozygous methylene tetrahydrofolate reductase (MTHFR) mutation were identified in seven patients (70%) and homozygous MTHFR mutation were found two patients (20%).Conclusion: In patients with hereditary angioedema, evaluation of protrombotic risk factors was crucial to estimate attack frequency-severity and treatment related thrombosis risk.Keywords: Hereditary angioedema; prothrombotic risk factors; C1 inhibitor; thrombosis.Öğe Multiple hepatic epithelioid hemangioendothelioma in an adolescent girl mimicking liver metastasis(2018) Yilmaz, Ebru; Yikilmaz, Ali; Gul Kirkas, Ozlem; Ozcan, Alper; Deniz, Kemal; Patiroglu, Turkan; Unal, Ekrem; Karakukcu, MusaÖğe Succesful treatment of extravasation injury with topical heparinoid in a pediatric patient(2017) Ozcan, Alper; Ergul, Ayse Betul; Akbiyik, Demet; Altuner Torun, Yasemin
