Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14517/19

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Analysis and Implementation of Sensorless Pmsm Drive With Reduced Dc-Link Capacitance Under Parameter Variations
(Ieee, 2024) Sumsek, Reha Ozgur; Calik, Ramazan; Yavuz, Fikri Serkan; Kivanc, Omer Cihan
In AC drives used in heating, ventilation and air-conditioning applications, film capacitors are becoming widespread instead of electrolytic capacitors in DC-link. These drives with reduced capacitor value provide cost and volume advantages. However, dc-link oscillation increases due to the reduced capacity value. These oscillations cause instability, overvoltage and an increase in total harmonic distortion (THD). On the other hand, the winding temperatures of these motors, which operate continuously under rated operating conditions, reach 80 degrees C. The stator resistance and rotor flux value, which change with the increase in temperature, cause these drives, controlled without sensors, to operate even more unstable. In this study, a hybrid approach is proposed to improve the performance of the inverter using a 16 mu F film capacitor at the dc-link and to reduce the THD. The active damping method regulates the inverter output voltage for DC-link voltage stabilization. A permanent magnet synchronous machine (PMSM) sensorless speed control based on stator feedforward voltage estimation and a model reference adaptive system (MRAS) based on a multiparameter estimation algorithm is performed to minimize the effects of parameter variations. As a result of the experimental studies, it is observed that the grid input current complies with the IEC61000-3-2 standard, even under severe parameter variations.
Anaplastic Thyroid Carcinoma
(Springer Science+Business Media, 2018) Kebudi, A.; Deveci, U.; Çitgez, B.
Anaplastic thyroid carcinoma (ATC) is a relatively uncommon highly malignant tumor originating from the follicular cells of the thyroid gland having a poor prognosis. It accounts for 2-5% of all thyroid carcinomas, and patients typically present with a rapidly growing anterior neck mass with aggressive symptoms. A 66-year-old male presented with dyspnea, neck pain, and voice changes. Ultrasonographic neck examination demonstrated an enlarged thyroid gland and substernal extension of the right thyroid lobe. Fine needle aspiration (FNA) from the thyroid nodule biopsy showed benign cytology. Because of symptomatic disease and radiologic malignancy doubt, operation has been done. Histopathologic examination with frozen section demonstrated anaplastic thyroid carcinoma. After total thyroidectomy, the patient is discharged. The patient died 20 days after the start of systemic treatment because of septic multiorgan failure derived from bronchopneumonic lung infection. In the evaluation of sudden growing neck masses in elderly patients, anaplastic thyroid cancer should be considered as a differential diagnosis, even if the needle biopsy is normal. © Springer International Publishing AG, part of Springer Nature 2019.
Artificial Neural Networks; Definition, Properties and Misuses
(Nova Science Publishers, Inc., 2011) Guresen, E.; Kayakutlu, G.
There are no such clear and good definitions of ANNs in the literature. Many of the definitions refer to the figures instead of well explaining the ANNs. That is why many weighted graphs (as in shortest path problem networks) fit the definition of ANN. This study aims to give a clear definition that will differentiate ANN and graphs (or networks) by referring to biological neural networks. Although there is no input choice limitation or prior assumption in ANN, sometimes researchers compare ANN achievements with the results of other methods using different input data and make comments on these results. This study also gives examples from literature to misuses, unfair comparisons and evaluates the underlying reasons which will guide researchers. © 2011 Nova Science Publishers, Inc. All rights reserved.
Barriers to E-Procurement Adoption: The Turkish Case
(IGI Global, 2009) Yamamoto, G.T.; Karaman, F.
E-procurement practice is not well-established in emerging countries. There are barriers in terms of transportation, financial, telecommunication, and legal infrastructures. Also, a lack of a qualified workforce, cultural barriers, and security problems hinder the development of e-procurement activities. These are not such significant problems in the developed countries. In this study, we examined the Turkish practice. We gave country background information including macroeconomic data and Internet penetration data, and we gave a picture of the current situation of Turkey. We then discussed how these barriers can be overcome in Turkey. Finally, we gave predictions about how m-procurement may alter the situation and its potential for the Turkish market. © 2010 by IGI Global. All rights reserved.
Business Ethics and Technology in Turkey: An Emerging Country at the Crossroad of Civilizations
(IGI Global, 2009) Yamamoto, G.T.; Karaman, F.
IT ethics cannot be analyzed without assessing business ethics in general and the cultural environment. This study is based on the Turkish case. Turkey lies at the crossroads of civilizations, making it hard to define a generally accepted set of ethical principles. Western, Islamic, and Turkish cultures are in competition with each of them, and a synthesis has not yet been achieved. Therefore, a common identity and common ethical standards cannot be acquired. In fact, such a synthesis could be categorized as a new civilization. This disagreement causes proliferation of unethical behaviors such as the illegal copying of software. The majority of highly educated technical people in Turkey approves of the illegal copying of software, if it is necessitated by the interests of the country. This shows that we have a long way to go to reach global ethical standards, and country-specific differences cannot be eliminated in the short term. © 2010 by IGI Global. All rights reserved.
Cardio-Oncology: Cancer and Treatment-Related Cardiotoxicity and Imaging Methods for Assessment of Cardiotoxicity
(Springer Nature, 2024) Guvenc, R.C.; Guler, E.C.; Güvenc, T.S.
Cardio-oncology is a new branch of cardiology that specializes in the diagnosis and treatment of cancer-related and treatment-related cardiac disorders in patients with malignant disease. Being a highly aggressive form of malignancy, esophageal cancer is known to locally invade nearby cardiac structures and great veins, as well as metastasize to the pericardium and myocardium. The chemoradiotherapy regimens used to treat this aggressive form of cancer also expose patients to the risk of treatment-induced cardiac damage and dysfunction. Imaging modalities for the diagnosis and follow-up of cardiac dysfunction range from simple transthoracic echocardiography to advanced imaging modalities such as speckle-tracking echocardiography to cardiac MRI. This chapter summarizes available evidence on the diagnosis and management of cardiotoxicity related to esophageal cancer and its various treatments, as well as imaging modalities used to monitor cancer- and treatment-related cardiac dysfunction. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.
Central nervous system parasites
(Nova Science Publishers, Inc., 2024) Aydinli, A.
When parasitic infections of the Central Nervous System (CNS) are examined, we encounter quite a lot of parasites. Among protozoans, especially free-living amoebae (such as Naegleria, Acanthamoeba, Balamuthia, and Sappinia) have attracted attention in recent years. In addition to these, Microsporidia (Encephalitozoon), Hartmanella, Malaria, Toxoplasma, etc. will appear. It is important that different parasites are identified using different laboratory methods and their treatments are also different. © 2024 Nova Science Publishers, Inc. All rights reserved.
Clinical Application of New Possible Biomarkers in the Assessment and Monitoring of Nutritional Status
(Bentham Science Publishers, 2022) Yesilkaya, B.
Nutrition is directly related to human health. It is very critical to determine the nutritional status to prevent or diagnose diseases and create the right treatment plans. The determination of the nutritional status provides an early diagnosis of growth and development retardation such as malnutrition. It also plays a major role in preventing diseases that may be caused by vitamin and mineral deficiencies. It helps in the surveillance of one of the world's most serious health problems, namely “obesity.” Different ways can be used to assess nutritional status. One of the best ways to assess the nutritional and health status is to use biomarkers. A biomarker is a substance whose detection indicates a specific disease state or a response to a therapeutic intervention. Biomarkers are used to detect nutrient consumption and deficiencies as early as possible, enabling early intervention for metabolic problems. Biomarkers also allow the visualization of diseases that a person might develop or potentially have with a sample, such as blood, tissue, and urine, from the person. Health interventions such as nutritional advice will preserve health or promote rapid recovery. In this chapter, the topic of biomarkers related to nutrition and nutrient deficiencies is discussed. The existence of new possible biomarkers is also reviewed. © 2022, Bentham Books imprint.
Comparative Evaluation of Canal Transportation and Centering Ability of Various Ni-Ti Rotary Systems in Retreatment of Curved Root Canals
(Selcuk University, 2022) Çiftçioğlu, E.; Küçükay, E.S.
Background: The aim of the present study was to evaluate the canal transportation and centering ability of ProTaper, HeroShaper and two Ni-Ti rotary systems developed for retreatment ProTaperRetreatment and R-Endo. Methods: One hundred twenty mesial canals of mandibular molars with curvatures between 30-40 degrees and radii of curvatures between 4-9 mm were embedded in a modified muffle system. The teeth were randomly divided into 8 groups (n=15). The roots were sectioned horizontally at 3, 6 and 9 mm from the working length. Cross-sections were digitally photographed under standardized conditions. Half of the root canals were prepared with ProTaper and the rest with HeroShaper. Postoperative photographs were obtained. Root canals were obturated with the respective guttapercha cones of the systems and AHPlus sealer. Following retreatment with four systems, photographs were assessed for the canal transportation in 8 directions, and centering ratio. The data were analyzed with Friedman test for repeated measurements, Kruskal Wallis test for intergroup comparisons and Dunn's multiple comparison test for subgroup comparisons, and significance was set at P < 0.05. Results: Initial shaping with ProTaper resulted in more significant transportation than HeroShaper (p<0.05). After retreatment, REndo yielded negative transportation values in the apical and midsections. In canals prepared with ProTaper, in the apical and coronal root sections ProTaperRetreatment, and in the midsections ProTaper revealed more acceptable re-shaping results. In the canals prepared with HeroShaper, after retreatment, transportation and centering ability were relatively efficient with HeroShaper in the apical and mid-sections; and with ProTaper in the coronal sections. Conclusion: All systems caused a certain amount of transportation and eccentricity. Protaper, ProtaperRetreatment and HeroShaper showed similar re-shaping performance with regard to the initial shaping procedure. However, R-Endo yielded insufficient root canal cleaning in the apical and mid-sections. © 2022, Selcuk University. All rights reserved.
Comparison of Apical Transportation and Canal Straightening Between Protaper Next, Hyflex, Reciproc and Reciproc Blue Instruments
(Selcuk University, 2022) Türkyilmaz, A.; Erdoğan, D.; Akbal Dinçer, G.; Erdemir, A.
Background: This study aimed to compare apical transportation and canal straightening of ProTaper Next, HyFlex Electric Discharge Machining, Reciproc and Reciproc Blue nickel-titanium (NiTi) files with different apical enlargements. Methods: Forty-eight mandibular molar human teeth were included in the study. The teeth were divided into four groups according to the NiTi file types (n=12). A digital radiographic method was used to compare apical transportation and canal straightening in the buccolingual and mesiodistal directions using before-and-after images superimposed with Image J software. The Kruskal-Wallis test with Bonferroni correction and the Wilcoxon test were used; the P value was set at 5%. Results: The maximum transportation of the buccolingual and mesiodistal directions were 0.216 mm and 0.196 mm with Reciproc file. The maximum straightening of the buccolingual and mesiodistal directions were degrees of 8.661 and 8.048 respectively with ProTaper Next and Reciproc files. Conclusion: ProTaper Next, HyFlex Electric Discharge Machining and Reciproc Blue filespresented similar results. Using a larger instrument increased the apical transportation and canal straightening. © 2022, Selcuk University. All rights reserved.
A Cooperative Positioning Method of Connected and Automated Vehicles With Fusion of Data Information of Direction-Of Relative Distance and Vehicles Speed
(Institute of Electrical and Electronics Engineers Inc., 2025) Kaky, K.M.; Bilgen, S.
This study explores the potential of cellular-vehicle-to-everything (C-V2X) wireless communications in enhancing AV localization in GNSS-deprived scenarios. Specifically, we propose CV2X-LOCA, a novel unit (RSU)-assisted cooperative localization substructure utilizing only C-V2X channel state information to achieve lane-level precision. CV2X-LOCA comprises four main components: a data processing module, environment parameter correction module, coarse positioning module, and vehicle trajectory filtering module, collectively addressing challenges in dynamic C-V2X networks. Through extensive modelling we demonstrate that CV2X-LOCA attains cutting-edge localization performance even in noisy conditions, with fast-moving vehicles and sparse RSU coverage. The findings offer valuable insights for transportation agencies to make informed decisions regarding cost-effective RSU deployment in the future. © 2025 IEEE.
Dental Students’ Anxiety Level, Awareness of Dental Anxiety, and Attitudes in Treating Patients With Dental Anxiety
(Selcuk University, 2022) Aykol Şahin, G.; Özden, Z.T.; Altan Köran, S.M.
Background: Successful treatment of patients with dental anxiety requires particular attitudes and knowledge. Dentists who have severe stress, inadequate knowledge, or less sensitivity to anxious patients may affect the success of the treatment. The aim of this study was to evaluate the general anxiety level and occupational perceptions of the final-year dental students and their attitudes to and knowledge level about anxious patients. Methods: The anxiety levels of the dental students were assessed by the Beck Anxiety Inventory. A questionnaire that evaluated professional perceptions, dental anxiety awareness, attitude, and knowledge level was conducted. The answers between the groups were compared, and differences were assessed statistically. Results: One hundred fifty-nine final-year dental students answered the questionnaire. No statistical difference was found between the anxiety levels of the students. 69,2% of students agreed that patients evaluate dentists with their style or behavior rather than their perceived technical competence. Female students and the students with adverse patient experiences perceived dentistry as a more stressful profession (respectively p=0,001, p=0,003). 39,6% of students had never taken a course related to dental anxiety. 25,8% of students thought that there is a relationship between dental anxiety and wound healing, and 37,1% of students thought that dental anxiety aggravates the inflammatory disease. Conclusion: The final-year dental students need more training in managing their stress and increasing their knowledge about anxious patients. There is a need for further studies involving dental anxiety management strategies with a higher number of dental students or dentists. © 2022, Selcuk University. All rights reserved.
Design and Implementation of a High Power Density GaN-Based USB-PD Charger
(Institute of Electrical and Electronics Engineers Inc., 2025) Er, B.; Bavtar, G.; Kivanc, O.C.
This paper presents the design and implementation of a high-power-density GaN-based USB-PD charger capable of delivering up to 100 W. Gallium Nitride (GaN) power devices offer significant advantages over traditional silicon-based components, including higher efficiency, reduced switching losses, and increased power density, making them an ideal choice for modern fast-charging applications. In this study, various power conversion topologies and commercially available GaN-based integrated circuits (ICs) are analyzed and compared to determine the most efficient and thermally optimized solution. Extensive thermal analysis is performed to evaluate the heat dissipation and efficiency of the system under full-load conditions. Experimental tests verified the charger's performance, demonstrating high efficiency and superior thermal management compared to conventional silicon-based solutions. The results highlight the potential of GaN technology in achieving compact, efficient, and high-power-density USB-PD chargers suitable for next-generation consumer electronics. © 2025 IEEE.
Design of a Position Controlled Electric Actuator Used in Fluid Control Valves
(IEEE, 2016) Tosun, Gurkan; Kivanc, O. Cihan; Oguz, Ender; Mutlu, Yasar; Ustun, Ozgur
Valves are the main elements for controlling fluids in industry and other application areas. To control flow precisely, valves need a controlled action which leads to implement actuators, gear systems and electronic controllers. Increasing dominance of electrical actuators due to the advantages of easy control and intervention and space-efficient designs brings seldom implementation of hydraulic and pneumatic actuation. In fluid control applications, the main target is to obtain the right position, i.e. angle for rotary actuators, for adjusting flow rate. In this study, the design and implementation of a position controlled electrically actuated valve used for fluid control are presented. The design phases of system universal power supply and electronic control system are given and the experimental results of position control which are representing the validation the design study is also discussed. Also a special current control scheme is used to overcome transient disruptions.
Development of a Lithium-Ion Hybrid Battery for Electric Forklifts
(Avestia Publishing, 2023) Özcan, M.A.; Yılmaz, C.H.; Tuncay, R.N.; Kıvanç, Ö.C.
Forklifts are widely used to transport loads in many facilities. Although the power of forklifts with internal combustion engine is quite sufficient, it is impossible to operate them in indoor environments such as factories and warehouses. For this reason, electric forklifts are used in indoor environments. For many years, lead acid batteries have been used as energy storage units in electric forklifts. While heavy lead acid batteries have a positive feature in terms of stability, the requirement of keeping spare batteries for each forklift is a must due to their slow charging phenomena. In addition, other disadvantages of lead acid batteries are that they need regular maintenance, have a low depth of discharge (DoD) and have a low cycle life [1]. This has made Li batteries more favorable. In parallel to the developments in general transportation applications, the usage of lithium-ion batteries in forklifts is spreading [2]. Despite the above advantages, lithium batteries are sensitive to excessive current pulses. For this reason, it is recommended to add supercapacitors to compensate the overcurrent pulses. Supercapacitors can supply very large current for a short time with cycle life up to 1,000,000 [3]. Thus, in this study a hybrid storage system is proposed. Thanks to the hybrid battery and an optimized energy management system, the high power pulses that exerted on the lithium-ion battery are cropped by the supercapacitor, and the peak current on the lithium-ion battery is decreased. The reduction of the pulse currents in lithium-ion batteries will have a positive effect on their State of Health (SoH) and State of Charge (SoC), the efficiency and the cost by reducing the battery capacity to lower levels. This study is on the design of a forklift battery with a Lithium Iron Phosphate (LFP) battery and Supercapacitor (SC). The measurements were made to obtain the load profile of an actively used forklift. The pulse currents during acceleration and regenerative braking were measured, and the necessity for adding a supercapacitor is justified. In addition, supercapacitor was tested. 10 kW power can be supplied for 10 seconds until its voltage is half of its rated voltage. The hybrid battery system of this study includes 80-volt LFP battery and 54-volt 166F supercapacitor. While the lithium-ion battery feeds the 80-volt DC bus, the 54-volt supercapacitor is connected to the DC bus via a bidirectional DC/DC converter. In order to operate this hybrid system efficiently a battery management and control system is developed. This system is not only control the power sharing between battery and super capacitor but also keep the Li battery in best operational condition. It is ensured that the batteries cell voltage, current and temperature limits are not exceeded. Thus, it will be possible to extend the life of the lithium-ion battery without sacrificing the performance capabilities of the forklift. © 2023, Avestia Publishing. All rights reserved.
Diş Hekimliğinde Fotopolimerizasyon ile 3 Boyutlu Üretim Yöntemleri ve Kullanım Alanları
(Selcuk University, 2023) Özay, M.; Saridağ, S.
In recent years with the rapid development of production technologies there has been a remarkable increase in the use of 3D printers. This technology, which is also used in the fields of aviation, defense, art and design, has an important place in dentistry. With many materials used with different methods, patient and dentist comfort is increased and working time is shortened. New production methods; contrary to traditional methods such as plaster model casting and orthodontic treatment with brackets, it has advanced the efficiency and success of treatments and has also enabled many new developments. Photopolymerized resins; in addition to the production of prosthetic base material, obturator, temporary crown-bridge, it is also used in the production of models in the field of dental education. The aim of this review is to provide an overview of the use of light-cured resins in the 3D production process. Also; it is aimed to give information about additive manufacturing technologies, materials used in these technologies, advantages and disadvantages. © 2023, Selcuk University. All rights reserved.
Drivers and Barriers to Adopting Sustainable Air Travel Behavior
(IGI Global, 2024) Tavman, E.B.
In recent years, concepts such as "sustainable aviation, " "sustainable flying, " and "carbon offset programs" have become more frequently heard. The number of sustainable aviation services is increasing daily, and with the rapid growth of the world economy, passenger flights worldwide are expected to double by 2040 (IATA, 2023). Air transportation accounts for 2.4% of all anthropogenic CO2 emissions and contributes three times more to global warming (Lee et al., 2021). Choosing sustainable air travel will help to reduce CO2 emissions and thus reduce the rate of global warming. However, the drivers and barriers affecting sustainable air travel choices have not yet been fully identified. A better understanding of sustainable airline preferences will enable the development of strategies for behavior change and more effective marketing efforts. In this section, the barriers and drivers to the adoption of sustainable aviation behavior will be discussed. © 2025, IGI Global Scientific Publishing. All rights reserved.
E-HRM as a Reality in Virtual World
(IGI Global, 2009) Yamamoto, G.T.; Özbek, A.
The human resources (HR) profession has had a rich history: that is, from the concept of labor unions in 1930 to the creation of selection tools in 1940 then to the reward systems in 1970 shifting to teamwork and then to partnerships in 1990. After the 1990s, like all other businesses, HR also influenced the Internet revolution. Classical human resources management (HRM) concerns the recruitment, selection, development, compensation, retention, evaluation, and promotion of personnel within an organization (Bernardin & Russel, 1993), which could be mostly transferred to the virtual world. Therefore, the HR profession faces an important challenge with new e-HRM and virtual actions encountered in the business world. This chapter examines the e-HRM phenomenon in the virtual world in detail and tries to bring new angles to e-HRM, and then manifests new definitions for the new reality while changes and interactions take place in the virtual world. © 2010 by IGI Global. All rights reserved.
Effect of Etl and Htl Layers on the Performance of Perovskite Solar Cells Using Scaps-1d Algorithm
(Institute of Electrical and Electronics Engineers Inc., 2024) Muslim, A.; Altürk, E.; Bilgiç, I.
The photovoltaic conversion efficiency of perovskite solar cells has been significantly improved by the global scientific community in a short period of time. From 3.8% to 25.7%, this efficiency has increased dramatically. The goal of the current study is to model perovskite solar cells and enhance the performance of hole and electron transport layers. In this study, the SCAPS-1D simulation software is employed to assess the efficiency of solar cells. This study elaborated on different Electron transport layers and hole transport layers with SCAPs-1D. TiO2 functions effectively as an electron transport layer, while Cu2O serves as an ideal hole transport layer. The device demonstrated an impressive photovoltaic conversion efficiency of 28.31%, an open-circuit voltage (Voc) of 1.09 V, a current density of 30.14 mA/cm2, and a fill factor of 85.93%. Thus, lead-free perovskite solar cells are environmentally friendly and promising for future solar cells. The objective of this study is to determine the ideal thickness of the absorbent layer. © 2024 IEEE.
Effect of External Innovation Capacity on Company Level Innovativeness
(Management & Business Acad, 2021) Okatan, Kagan; Alankus, Orhan Behic
This study focuses on the correlation of national innovation inputs and the external innovation environment with the company-level innovation output. Since all companies are aiming at sustainable innovation to ensure sustainable profit growth, the current literature has highlighted the need for a well-structured internal innovation system for innovation success and discussed the factors affecting the performance of organisations. The internal innovation system has its own dimensions that affect the success of the whole system and emphasize the significant impact of firms on innovation results. Do all companies with a high internal innovation competency and a suitable corporate culture have the chance to become worldwide innovative? What are the impacts of the external environment where the companies are located on the innovation success? And how big is the importance of external environmental inputs? This study seeks to answer these questions and draws attention to the appropriate external environment and conditions to increase firms' innovation competencies.

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