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      • KCI등재

        Determination of the stage and grade of periodontitis according to the current classification of periodontal and peri-implant diseases and conditions (2018) using machine learning algorithms

        Kübra Ertaş,Ihsan Pence,Melike Siseci Cesmeli,Zuhal Yetkin Ay 대한치주과학회 2023 Journal of Periodontal & Implant Science Vol.53 No.1

        Purpose: The current Classification of Periodontal and Peri-Implant Diseases and Conditions, published and disseminated in 2018, involves some difficulties and causes diagnostic conflicts due to its criteria, especially for inexperienced clinicians. The aim of this study was to design a decision system based on machine learning algorithms by using clinical measurements and radiographic images in order to determine and facilitate the staging and grading of periodontitis. Methods: In the first part of this study, machine learning models were created using the Python programming language based on clinical data from 144 individuals who presented to the Department of Periodontology, Faculty of Dentistry, Süleyman Demirel University. In the second part, panoramic radiographic images were processed and classification was carried out with deep learning algorithms. Results: Using clinical data, the accuracy of staging with the tree algorithm reached 97.2%, while the random forest and k-nearest neighbor algorithms reached 98.6% accuracy. The best staging accuracy for processing panoramic radiographic images was provided by a hybrid network model algorithm combining the proposed ResNet50 architecture and the support vector machine algorithm. For this, the images were preprocessed, and high success was obtained, with a classification accuracy of 88.2% for staging. However, in general, it was observed that the radiographic images provided a low level of success, in terms of accuracy, for modeling the grading of periodontitis. Conclusions: The machine learning-based decision system presented herein can facilitate periodontal diagnoses despite its current limitations. Further studies are planned to optimize the algorithm and improve the results.

      • KCI등재

        Apelin Levels In Isolated Coronary Artery Ectasia

        Mehmet Zihni Bilik,İbrahim Kaplan,Abdulkadir Yıldız,Mehmet Ata Akıl,Halit Acet,Murat Yüksel,Nihat Polat,Mesut Aydın,Mustafa Oylumlu,Faruk Ertaș,Hasan Kaya,Sait Alan 대한심장학회 2015 Korean Circulation Journal Vol.45 No.5

        Background and Objectives: The etiopathogenesis of coronary artery ectasia (CAE) is not known completely. In most of the cases, CAE is associated with atherosclerosis; however, isolated CAE has a nonatherosclerotic mechanism. The association between atherosclerotic coronary artery disease and apelin has been examined in previous studies. However, the role of plasma apelin in isolated coronary artery ectasia has not been studied. In this study, we investigated the relationship between plasma apelin levels and isolated coronary artery ectasia. Subjects and Methods: The study population included a total of 54 patients. Twenty-six patients had isolated CAE (53.6±8.1 years); 28 patients with normal coronary arteries (51.6±8.8 years) and with similar risk factors and demographic characteristics served as the control group. Apelin levels were measured using an enzyme-linked immunoassay kit. Results: Apelin level in the CAE group was significantly lower (apelin=0.181±0.159 ng/mL) than that in the control group (apelin=0.646±0.578 ng/mL) (p=0.033). Glucose, creatinine, total cholesterol, triglyceride, low density lipoprotein cholesterol, and high density lipoprotein cholesterol levels were not significantly different between the two groups. Conclusion: In this study, we showed that patients with isolated CAE have decreased plasma apelin levels compared with the control group. Based on the data, a relationship between plasma apelin and isolated CAE was determined.

      • Predictive Value of Malignancy Risk Indices for Ovarian Masses in Premenopausal and Postmenopausal Women

        Ertas, Sinem,Vural, Fisun,Tufekci, Ertugrul Can,Ertas, Ahmet Candost,Kose, Gultekin,Aka, Nurettin Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.4

        Background: To evaluate the predictive role of a risk of malignancy index in discriminating between benign and malignant adnexal masses preoperatively. Materials and Methods: A total of 408 patients with adnexal masses managed surgically between January 2010 and February 2014 were included. The risk of malignancy indices (RMI) 1, 2, 3 and 4 were calculated using findings for ultrasonography, menopausal status, and CA125 levels. Histopathologic results were the end point. ROC analysis was used for the sensitivity and the specificity of the models. Results: Some 37.6 % of the cases were malignant in the postmenopausal group while 7.9 % were malignant in the premenopausal group. Pelvic pain was the most common complaint, and the majority of the cases were diagnosed at stage 3. The RMI 1, 2, 3 and 4 yielded percentage sensitivities of 76.1, 79.1, 76.1 and 76.1 and specificities of 91.5, 89.1, 90.6, 88.6, respectively. RMI 1 was the most reliable test in the general population according to AUC levels and Kappa statistics. From ROC analysis results of post/premenopausal women, the RMI 1 (cut off: 200) yielded sensitivities of 84.0/60.9 and specificities of 87.7/92.5. With RMI 2 they were 88.6/60.9 and 80.0/91.0, with RMI 3 84.0/60.9 and 87.7/91.8, and with RMI 4 (cut off:400) 81.8/47.8 and 83.6 /44.0. Although test performance of RMI methods were good in a general population and postmenopausal women, the RMI inter-agreement validity was only moderate or fair in premenopausal women. Conclusions: Our study confirms the effectiveness of RMI algorithms in postmenopausal women. However, more sensitive tests are needed for premenopausal women.

      • KCI등재

        Induction of Apoptosis in Intestinal Toxicity to a Histone Deacetylase Inhibitor in a Phase I Study with Pelvic Radiotherapy

        Erta Kalanxhi,Karianne Risberg,Imon S. Barua,Svein Dueland,Stein Waagene,Solveig Norheim Andersen,Solveig J. Pettersen,Jessica M. Lindvall,Kathrine Røe Redalen,Kjersti Flatmark,Anne Hansen Ree 대한암학회 2017 Cancer Research and Treatment Vol.49 No.2

        Purpose When integrating molecularly targeted compounds in radiotherapy, synergistic effects of the systemic agent and radiation may extend the limits of patient tolerance, increasing the demand for understanding the pathophysiological mechanisms of treatment toxicity. In this Pelvic Radiation and Vorinostat (PRAVO) study, we investigated mechanisms of adverse effects in response to the histone deacetylase (HDAC) inhibitor vorinostat (suberoylanilide hydroxamic acid, SAHA) when administered as a potential radiosensitiser. Materials and Methods This phase I study for advanced gastrointestinal carcinoma was conducted in sequential patient cohorts exposed to escalating doses of vorinostat combined with standard-fractionated palliative radiotherapy to pelvic target volumes. Gene expression microarray analysis of the study patient peripheral blood mononuclear cells (PBMC) was followed by functional validation in cultured cell lines and mice treated with SAHA. Results PBMC transcriptional responses to vorinostat, including induction of apoptosis, were confined to the patient cohort reporting dose-limiting intestinal toxicities. At relevant SAHA concentrations, apoptotic features (annexin V staining and caspase 3/7 activation, but not poly-(ADP-ribose)-polymerase cleavage) were observed in cultured intestinal epithelial cells. Moreover, SAHA-treated mice displayed significant weight loss. Conclusion The PRAVO study design implemented a strategy to explore treatment toxicity caused by an HDAC inhibitor when combined with radiotherapy and enabled the identification of apoptosis as a potential mechanism responsible for the dose-limiting effects of vorinostat. To the best of our knowledge, this is the first report deciphering mechanisms of normal tissue adverse effects in response to an HDAC inhibitor within a combined-modality treatment regimen.

      • SCIESCOPUS

        Simulation-based fatigue life assessment of a mercantile vessel

        Ertas, Ahmet H.,Yilmaz, Ahmet F. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.6

        Despite the availability of other transport methods such as land and air transportations, marine transportation is the most preferred and widely used transportation method in the world because of its economical advantages. In service, ships experience cyclic loading. Hence, it can be said that fatigue fracture, which occurs due to cyclic loading, is one of the most critical failure modes for vessels. Accordingly, this makes fatigue failure prevention an important design requirement in naval architecture. In general, a ship structure contains many structural components. Because of this, structural modeling typically relies on Finite Element Analysis (FEA) techniques. It is possible to increase fatigue performance of the ship structures by using FEA in computer aided engineering environment. Even if literature papers as well as rules of classification societies are available to assess effect of fatigue cracks onto the whole ship structure, analytical studies are relatively scarce because of the difficulties of modeling the whole structure and obtaining reliable fatigue life predictions. As a consequence, the objective of this study is to improve fatigue strength of a mercantile vessel against fatigue loads via analytical method. For this purpose, the fatigue life of the mercantile vessel has been investigated. Two different type of fatigue assessment models, namely Coffin-Manson and Morrow Mean stress approaches, were used and the results were compared. In order to accurately determine the fatigue life of the ship, a nonlinear finite element analysis was conducted considering plastic deformations and residual stresses. The results of this study will provide the designer with some guidelines in designing mercantile vessels.

      • KCI등재

        Simulation-based fatigue life assessment of a mercantile vessel

        Ahmet H. Ertas,Ahmet F. Yilmaz 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.6

        Despite the availability of other transport methods such as land and air transportations, marine transportation is the most preferred and widely used transportation method in the world because of its economical advantages. In service, ships experience cyclic loading. Hence, it can be said that fatigue fracture, which occurs due to cyclic loading, is one of the most critical failure modes for vessels. Accordingly, this makes fatigue failure prevention an important design requirement in naval architecture. Ingeneral, a ship structure contains many structural components. Because of this, structural modeling typically relies on Finite Element Analysis (FEA) techniques. It is possible to increase fatigue performance of the ship structures by using FEA in computer aided engineering environment. Even if literature papers as well as rules of classification societies are available to assess effect of fatigue cracks onto the whole ship structure, analytical studies are relatively scarce because of the difficulties of modeling the whole structure and obtaining reliable fatigue life predictions. As a consequence, the objective of this study is to improve fatigue strength of a mercantile vessel against fatigue loads via analytical method. For this purpose, the fatigue lifeof the mercantile vessel has been investigated. Two different type of fatigue assessment models, namely Coffin-Manson and Morrow Mean stress approaches, were used and the results were compared. In order to accurately determine the fatigue life of the ship, a nonlinear finite element analysis was conducted considering plastic deformations and residual stresses. The results of this study will provide the designer with some guidelines in designing mercantile vessels.

      • KCI등재

        Design optimization of spot welded structures to attain maximum strength

        Ahmet H. Ertas 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.4

        This study presents design optimization of spot welded structures to attain maximum strength by using the Nelder-Mead (Simplex) method. It is the main idea of the algorithm that the simulation run is executed several times to satisfy predefined convergence criteria and every run uses the starting points of the previous configurations. The material and size of the sheet plates are the pre-assigned parameters which do not change in the optimization cycle. Locations of the spot welds, on the other hand, are chosen to be design variables. In order to calculate the objective function, which is the maximum equivalent stress, ANSYS, general purpose finite element analysis software, is used. To obtain global optimum locations of spot welds a methodology is proposed by modifying the Nelder-Mead (Simplex) method. The procedure is applied to a number of representative problems to demonstrate the validity and effectiveness of the proposed method. It is shown that it is possible to obtain the global optimum values without stacking local minimum ones by using proposed methodology.

      • An investigation of non-linear optimization methods on composite structures under vibration and buckling loads

        Akbulut, Mustafa,Sarac, Abdulhamit,Ertas, Ahmet H. Techno-Press 2020 Advances in computational design Vol.5 No.3

        In order to evaluate the performance of three heuristic optimization algorithms, namely, simulated annealing (SA), genetic algorithm (GA) and particle swarm optimization (PSO) for optimal stacking sequence of laminated composite plates with respect to critical buckling load and non-dimensional natural frequencies, a multi-objective optimization procedure is developed using the weighted summation method. Classical lamination theory and first order shear deformation theory are employed for critical buckling load and natural frequency computations respectively. The analytical critical buckling load and finite element calculation schemes for natural frequencies are validated through the results obtained from literature. The comparative study takes into consideration solution and computational time parameters of the three algorithms in the statistical evaluation scheme. The results indicate that particle swarm optimization (PSO) considerably outperforms the remaining two methods for the special problem considered in the study.

      • KCI등재

        Dynamic Phase Transition and Multicritical Dynamic Phase Diagrams of The Kinetic Spin-2 Ising Model With Repulsive Biquadratic Coupling under a Time-dependent Oscilating External Field

        Mustafa Keskin,Mehmet Ertas,Osman Canko 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.4

        We calculate the dynamic phase transition (DPT) temperatures and present the dynamic phase diagrams in the kinetic spin-2 Blume-Emery-Griffiths model with repulsive biquadratic coupling under the presence of a time-dependent oscillating external magnetic eld. First, we employ the Glauber transition rates to construct the set of mean-field dynamic equations. Then, we study the time variation of the average order parameters to nd the phase in the system. We also investigate the behavior of the dynamic order parameters to characterize the nature (continuous or discontinu- ous)of the transition and to obtain the DPT points. We present the dynamic phase diagrams in the plane of the reduced temperature versus magnetic field amplitude. The phase diagrams exhibit the ferrimagnetic, ferromagnetic -1, antiquadrupolar and disordered fundamen- tal phases. In addition to these fundamental phases, depending on the interaction parameters, we find ten coexisting or mixed phases composed of binary and ternary combinations of fundamental phases. The phase diagrams also display many special points, such as a dynamic tricritical point, a zero-temperature critical point, a critical end point, a double critical end point, a multicritical point, a triple point and a tetracritical point.

      • KCI등재

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