Advancing research on comparative and international education in Asia: contribution of the Asia Pacific Education Review

Enes Gok,John C. Weidman 서울대학교 교육연구소 2015 Asia Pacific Education Review Vol.16 No.3

This article explored the contribution of Asia Pacific Education Review (APER) to expanding the scope of research on comparative and international education in Asia. We developed a rubric based on extensive studies (Rust et al. in Comp Educ Rev, 43(1):86–109, 1999; Foster et al. in Int J Educ Dev 32:711–732, 2012) of research in the field to compare three highly ranked journals in the field of comparative and international education (Comparative Education, Comparative Education Review, and International Journal of Educational Development) with the fledgling APER on the content of the articles they published between 2006 and 2010. Results were also compared with sources included in the 2011, 2012, and 2013 bibliographies prepared for the Comparative Education Review. The study highlights publication patterns of these journals, focusing on methodology, education level, region, and topics. Findings suggest that these journals, while sharing some things in common, also show distinct patterns, suggesting questions about the extent to which distinctively Asian topics and approaches are fully represented.

Non-preemptive Queueing Model of Spectrum Handoff Scheme Based on Prioritized Data Traffic in Cognitive Wireless Networks

Muhammed Enes Bayrakdar,Ali Çalhan 한국전자통신연구원 2017 ETRI Journal Vol.39 No.4

In this study, a non-preemptive M/G/1 queueing model of a spectrum handoff scheme for cognitive wireless networks is proposed. Because spectrum handoff gives secondary users an opportunity to carry on their transmissions, it is crucially important to determine the actions of primary users. In our queueing model, prioritized data traffic is utilized to meet the requirements of the secondary users. These users’ packets are categorized into three different priority classes: urgent, real-time, and non-real time. Urgent data packets have the highest priority, while non-real time data packets have the lowest priority. Riverbed (OPNET) Modeler simulation software was used to simulate both reactive and proactive decision spectrum handoff schemes. The simulation results were consistent with the analytical results obtained under different load and traffic conditions. This study also revealed that the cumulative number of handoffs can be drastically decreased by exploiting priority classes and utilizing a decent spectrum handoff strategy, such as a reactive or proactive decision-based strategy.

Weight Optimization of the Gearbox Using Interior Point Method

Mehmet Enes Avcu,Harun Gökçe 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.1

Weight is important subject to industry that produce machine like truck, grader etc. Thus, weight optimization problem is challenging area to work at optimization area. A few optimization solution is already exit in literature. However, these algorithms are meta-heuristic algorithms. In this study, numerical optimization algorithm implemented for weight optimization problem. The interior point method (IPM) is most powerful algorithm for nonlinear programming (Nocedal and Wright in Numerical optimization, Springer, Berlin, 2006). We show the result of IPM algorithm and check against meta-heuristic algorithms.

Exploiting cognitive wireless nodes for priority-based data communication in terrestrial sensor networks

Bayrakdar, Muhammed Enes Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.1

A priority-based data communication approach, developed by employing cognitive radio capacity for sensor nodes in a wireless terrestrial sensor network (TSN), has been proposed. Data sensed by a sensor node-an unlicensed user-were prioritized, taking sensed data importance into account. For data of equal priority, a first come first serve algorithm was used. Non-preemptive priority scheduling was adopted, in order not to interrupt any ongoing transmissions. Licensed users used a nonpersistent, slotted, carrier sense multiple access (CSMA) technique, while unlicensed sensor nodes used a nonpersistent CSMA technique for lossless data transmission, in an energy-restricted, TSN environment. Depending on the analytical model, the proposed wireless TSN environment was simulated using Riverbed software, and to analyze sensor network performance, delay, energy, and throughput parameters were examined. Evaluating the proposed approach showed that the average delay for sensed, high priority data was significantly reduced, indicating that maximum throughput had been achieved using wireless sensor nodes with cognitive radio capacity.

Steady State Voltage Stability Estimation by Using Local Bus Parameters

Gümüş Talha Enes,Yalçın Mehmet Ali,Turan Mustafa,Aksoy Tırmıkçı Ceyda,Yavuz Cenk 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

In this study, an estimation approach based on local bus measurements of voltage, current and phase angle is presented to assess voltage stability at any of the system load bus. For this purpose, Thevenin equivalent circuit parameters of the IEEE 30-bus standard test system are estimated by using local measurements from Bus k which is selected to be evaluated in terms of voltage stability. Estimated Thevenin equivalent circuit parameters are used to calculate critical voltage values and voltage stability margin values of Bus k online for the voltage stability assessment. In conclusion, the voltage stability margin results of the proposed approach are compared with three diff erent Thevenin equivalent based voltage stability estimation approaches. Simulation results show that the proposed approach successfully estimates the voltage stability margins of any load bus in the system. From the perspective of voltage stability, estimated voltage stability margins can be used to assess the loading levels of any load bus, to defi ne critical busses and to make decision for load shedding.

Experimental and theoretical investigation of phosphorus in-situ doping of germanium epitaxial layers

유현용,Enes Battal,Ali Kemal Okyay,Jaewoo Shim,박진홍,백정우,Krishna C. Saraswat 한국물리학회 2013 Current Applied Physics Vol.13 No.6

We investigate phosphorus in-situ doping characteristics in germanium (Ge) during epitaxial growth by spreading resistance profiling analysis. In addition, we present an accurate model for the kinetics of the diffusion in the in-situ process, modeling combined growth and diffusion events. The activation energy and pre-exponential factor for phosphorus (P) diffusion are determined to be 1.91 eV and 3.75 x 105 cm2/s. These results show that P in-situ doping diffusivity is low enough to form shallow junctions for high performance Ge devices.

The Importance of Arrhythmia Burden for Outcomes and Management Related to Catheter Ablation of Atrial Fibrillation

Paula Sánchez-Somonte,Enes Elvin Gul,Atul Verma 대한심장학회 2021 Korean Circulation Journal Vol.51 No.6

Atrial fibrillation (AF) ablation has been shown to be an effective treatment for AF, although our understanding of AF ablation outcomes until now, has been based on AF recurrence as a dichotomous variable. Reduction in AF burden, defined as the proportion of time that an individual is in AF during a monitoring period, has been already correlated to an improvement in quality of life and is likely a better assessment of success. Clinically, many patients may still have a few short recurrences of AF but feel much better. In addition, several studies have related higher AF burden with poorer health outcomes and a higher risk of stroke. Despite the growing understanding of AF burden, it is not clear yet which threshold of AF burden would be considered an appropriate outcome measure for AF ablation. Further investigations are needed to address that question. However, the reduction of AF burden seems to be a more accurate reflection of procedural success and a better predictor of prognosis and stroke risk than a single measure of AF.

Core-Type Transformer Design Method with Integrated Series Inductance for DC-DC Converters

Murat Kaymak,Mustafa Enes Fincan,Rik W. De Doncker 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper presents two different methods to design Medium-Frequency Transformers (MFT) with required ac-link series inductance of a galvanically isolated dc-dc converter. The series inductance of the ac-link is usually formed by the leakage or stray inductance of the MFT and an additional external inductor. Here, two approaches are presented, avoiding the extra external series inductor by designing the transformer with an increased and defined leakage inductance.

Investigation of the Microstructure and Mechanical Characteristics of Lattice Structures Produced by Laser Powder Bed Fusion Method

A. Tamer Erturk,M. Enes Bulduk,Gürkan Tarakçi,Gökhan Özer,Eser Yarar 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

This study includes experimental research conducted to produce lattice structures and to examine their mechanical properties by taking advantage of the design freedom provided by additive manufacturing. Much of the existing literature involvesmainly process parameters on mechanical behaviors. Thus, more lattice geometry studies are needed. In this study, diferentlattice structures designed according to the unit cell types selected through the SpaceClaim program were produced usingAlSi10Mg powder material with the laser powder bed fusion (LPBF) method the metal additive manufacturing productionmethods. Cell sizes, Maxwell criterion, relative densities, and mechanical behaviors under semi-static compression forcewere investigated. It was concluded that with increasing relative density, the strength increased, and the structures withstress-dominating were more resistant than those with bending-dominating strength. It was determined that the mechanicalproperties of lattices depended on unit cell design and LPBF process parameters. The C1 and C2 coefcients of latticesproduced by the LPBF process included in the Gibson and Ashby equation were determined.

Can ultrasound-guided infraclavicular block be an alternative option for forearm reduction in the emergency department? A prospective randomized study

Erdal Tekin,Muhammed Enes Aydin,Mehmet Cenk Turgut,Selahattin Karagoz,Irem Ates,Elif Oral Ahiskalioglu 대한응급의학회 2021 Clinical and Experimental Emergency Medicine Vol.8 No.4

Objective Ultrasound-guided infraclavicular nerve block (IB) has become a well-established method in several outpatient procedures; however, its use in emergency departments (EDs) remains limited. The aim of this study was to compare procedural sedation and anlagesia (PSA) and IB in the pain management for patients who underwent forearm fracture reduction in the ED. Methods This prospective randomized study included 60 patients aged 18 to 65 years, who visited the ED with forearm fractures. They were randomly divided into two groups: Group PSA (n=30) and Group IB (n=30). The pain scores of patients were evaluated before and during the procedure with the visual analog scale. Complications and patient and operator satisfaction levels were recorded. Results There was no difference between the two groups in terms of demographic characteristics. The median (interquartile range) pain scores observed during the procedures were significantly higher in Group PSA than in Group IB (4 [4–6] vs. 2 [0–2], respectively; P