Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14365/3

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Citation - Scopus: 318
1-D Convolutional Neural Networks for Signal Processing Applications
(Institute of Electrical and Electronics Engineers Inc., 2019-05) Kiranyaz, Serkan; İnce, Türker; Abdeljaber, O.; Avci, O.; Gabbouj, M.
1D Convolutional Neural Networks (CNNs) have recently become the state-of-the-art technique for crucial signal processing applications such as patient-specific ECG classification, structural health monitoring, anomaly detection in power electronics circuitry and motor-fault detection. This is an expected outcome as there are numerous advantages of using an adaptive and compact 1D CNN instead of a conventional (2D) deep counterparts. First of all, compact 1D CNNs can be efficiently trained with a limited dataset of 1D signals while the 2D deep CNNs, besides requiring 1D to 2D data transformation, usually need datasets with massive size, e.g., in the »Big Data» scale in order to prevent the well-known »overfitting» problem. 1D CNNs can directly be applied to the raw signal (e.g., current, voltage, vibration, etc.) without requiring any pre- or post-processing such as feature extraction, selection, dimension reduction, denoising, etc. Furthermore, due to the simple and compact configuration of such adaptive 1D CNNs that perform only linear 1D convolutions (scalar multiplications and additions), a real-time and low-cost hardware implementation is feasible. This paper reviews the major signal processing applications of compact 1D CNNs with a brief theoretical background. We will present their state-of-the-art performances and conclude with focusing on some major properties. Keywords - 1-D CNNs, Biomedical Signal Processing, SHM. © 2019 IEEE.
A 2-Hop Coloring-Based Collision Free Infrastructure Design for Wireless Sensor Networks
(Institute of Electrical and Electronics Engineers Inc., 2016-10) Korkmaz I.; Dagdeviren O.; Dalkilic M.E.
This paper mainly proposes a design for a communication infrastructure for Wireless Sensor Networks. The proposed design prevents message collisions by arranging the time schedules to send, receive, forward and overhear packets of the nodes considering 2-hop graph coloring mechanism. The system aims to exclude the compromised nodes in the network using the overhearing mechanism, and copes with recovering the paths of the legitimate nodes using multipath redundancy. The proposed scheduling-based and overhearing supported infrastructure brings the advantage of providing the Sensor Networks with both reliable communication using backup paths and energy conservation by preventing the collisions. © 2016 IEEE.
Citation - WoS: 4
Citation - Scopus: 5
3d Helmholtz Coil System Setup for Thermal Conductivity Measurements of Magnetic Nanofluids
(Pergamon-Elsevier Science Ltd, 2023-10) Alsangur, Rahime; Dog, Serkan; Ateş, Ismet; Turgut, Alpaslan; Çetin, Levent; Doğanay, Serkan
This study aims to design a mechatronic system that involves a 3D Helmholtz coil system implemented with the 3 omega; method to measure the thermal conductivity of magnetic nanofluids under uniform and rotating magnetic fields. For this purpose, a 3D Helmholtz coil system was designed and manufactured to generate a uniform and rotating magnetic field up to 400 G. First, the uniformity and rotation abilities of the magnetic field generated by the system were investigated numerically and experimentally. The investigations pointed out that the 3D Helmholtz coil system can generate a uniform magnetic field in 1D, 2D, and 3D with a maximum non-uniformity factor of 0.0016. After that, the thermal conductivity of Fe3O4 - water magnetic nanofluid samples with 1, 2, 3, 4, and 4.8 vol.% were measured under 1D, 2D, and 3D uniform magnetic field application. The magnetic field was applied at different direction angles between X, Y, and Z axes in the Cartesian coordinate system. The results pointed out that the thermal conductivity of the samples increases as the magnetic field and particle concentration increase. The maximum thermal conductivity enhancement was observed as similar to 9.1% and the minimum thermal conductivity was observed as similar to 1.9% when the magnetic field is applied in parallel and perpendicular directions, respectively. The measurement results also pointed out that under the external uniform magnetic field application at 2D and 3D, thermal conductivity enhancement is less affected by the particle concentration increment.
3d Printing With Bacterial Cellulose-Based Bioactive Composites for Design Applications
(Ecaade-education & research computer aided architectural design europe, 2022) Turhan, Gözde Damla; Afşar, Seçil; Özel, Berfin; Doyuran, Aslıhan; Varinlioglu, Güzden; Bengisu, Murat
The bacterial cellulose (BC) biofilms are explored in design applications as replacements to petroleum-based materials in order to overcome the irreversible effects of the Anthropocene. Unlike biomaterials, designers as mediators could collaborate with bioactive polymers as a form of wetware to manufacture living design products with the aid of novel developments in biology and engineering. Past and ongoing experiments in the literature show that BC has a strong nanofibril structure that provides adhesion for attachment to plant cellulose-based networks and it could grow on the surfaces of the desired geometry thanks to its inherited, yet, controllable bio-intelligence. This research explores BC-based bioactive composites as wetware within the context of digital fabrication in which the methodology involves distinct, yet integrated, three main stages: Digital design and G-code generation (software stage); BC cultivation and printable bioactive composite formulation (wetware stage); digital fabrication with a customized 3D printer (hardware stage). The results have shown that the interaction of BC and plant-based cellulose fibers of jute yarns has enhanced the structural load-bearing capacity of the form against compressive forces, while pure BC is known only by its tensile strength. Since the outcomes were fabricated with the use of a bioactive material, the degradation process also adds a fourth dimension: Time, by which the research findings could further establish a bio-upcycling process of wastes towards biosynthesis of valuable products. Moreover, developing a BC-based bioactive filament indicates potentially a feasible next step in the evolution of multiscale perspectives on the growth of habitable living structures that could reinforce the interaction between nature and architecture through collaboration with software, hardware, and wetware in innovative and sustainable ways.
Citation - Scopus: 3
3d Printing With Bacterial Cellulose-Based Bioactive Composites for Design Applications
(Education and research in Computer Aided Architectural Design in Europe, 2022) Turhan G.D.; Afsar S.; Ozel B.; Doyuran A.; Varinlioglu G.; Bengisu, Murat
The bacterial cellulose (BC) biofilms are explored in design applications as replacements to petroleum-based materials in order to overcome the irreversible effects of the Anthropocene. Unlike biomaterials, designers as mediators could collaborate with bioactive polymers as a form of wetware to manufacture living design products with the aid of novel developments in biology and engineering. Past and ongoing experiments in the literature show that BC has a strong nanofibril structure that provides adhesion for attachment to plant cellulose-based networks and it could grow on the surfaces of the desired geometry thanks to its inherited, yet, controllable bio-intelligence. This research explores BC-based bioactive composites as wetware within the context of digital fabrication in which the methodology involves distinct, yet integrated, three main stages: Digital design and G-code generation (software stage); BC cultivation and printable bioactive composite formulation (wetware stage); digital fabrication with a customized 3D printer (hardware stage). The results have shown that the interaction of BC and plant-based cellulose fibers ofjute yarns has enhanced the structural load-bearing capacity of the form against compressive forces, while pure BC is known only by its tensile strength. Since the outcomes were fabricated with the use of a bioactive material, the degradation process also adds a fourth dimension: Time, by which the research findings could further establish a bio-upcycling process of wastes towards biosynthesis of valuable products. Moreover, developing a BC-based bioactive filament indicates potentially a feasible next step in the evolution of multiscale perspectives on the growth of habitable living structures that could reinforce the interaction between nature and architecture through collaboration with software, hardware, and wetware in innovative and sustainable ways. © 2022, Education and research in Computer Aided Architectural Design in Europe. All rights reserved.
The Abject Other in Turkish Politics: Populist Securitization, Affect, and the Victory Party
(Routledge Journals, Taylor & Francis Ltd, 2026-04-02) Kıcıroğlu, Ceren Melis; Adısönmez, Umut Can; Ermihan, Erman
This article examines the populist securitization of migration in Turkey through Julia Kristeva's concept of abjection, arguing that refugees are discursively constructed as the 'abject other,' contaminating the imagined national body. Far-right actors normalize exclusionary politics by mobilizing affects of disgust, fear, and anger to dramatize crisis, scapegoat refugees for socioeconomic grievances, and demand extraordinary measures. Drawing on discourse analysis (2011-2025), the study traces how metaphors of dirt, invasion, and purification are translated into securitizing logics. This dynamic is crystallized in the discourse of the Victory Party (Zafer Partisi) and its leaderÜmitÖzdağ, whose rhetoric diffuses contagiously across the political spectrum. Integrating Kristeva's psychoanalytic framework with scholarship on populism and securitization, the article theorizes how affective economies of revulsion underpin exclusionary politics. The findings reveal a paradox: far-right actors in Turkey remain electorally weak yet discursively hegemonic, illuminating affect-driven populist securitization in non-Western contexts and its global implications.
Citation - WoS: 9
Citation - Scopus: 17
Abnormal Ecg Beat Detection Based on Convolutional Neural Networks
(Institute of Electrical and Electronics Engineers Inc., 2020-11-19) Ozdemir M.A.; Guren O.; Cura O.K.; Akan A.; Onan A.; Ozdemir, Mehmet Akif; Guren, Onan; Cura, Ozlem Karabiber; Akan, Aydin; Onan, Aytug
The heart is the most critical organ for the sustainability of life. Arrhythmia is any irregularity of heart rate that causes an abnormality in your heart rhythm. Clinical analysis of Electrocardiogram (ECG) signals is not enough to quickly identify abnormalities in the heart rhythm. This paper proposes a deep learning method for the accurate detection of abnormal and normal heartbeats based on 2-D Convolutional Neural Network (CNN) architecture. Two channels of ECG signals were obtained from the MIT-BIH arrhythmia dataset. Each ECG signal is segmented into heartbeats, and each heartbeat is transformed into a 2-D grayscale heartbeat image as an input for CNN structure. Due to the success of image recognition, CNN architecture is utilized for binary classification of the 2-D image matrix. In this study, the effect of different CNN architectures is compared based on the classification rate. The accuracies of training and test data are found as 100.00% and 99.10%, respectively for the best CNN model. Experimental results demonstrate that CNN with ECG image representation yields the highest success rate for the binary classification of ECG beats compared to the traditional machine learning methods, and one-dimensional deep learning classifiers. © 2020 IEEE.
Accounting for digital products
(IGI Global, 2010) Karaibrahimo?lu Y.Z.
Digital products are "content" goods such as software, books, music, or movies which can be digitized and traded on a digital market place. With the increase in trade and ownership of digital products, several important management issues have arisen. Accounting treatment for digital products is one important management issue. It is argued that digital products require regulations in terms of recognition, measurement, valuation, reporting and taxation. Therefore, the purpose of this chapter is to discuss the accounting problems that arise as a result of the growing importance of digital products in the business environment and to propose suggestions based on the accounting concepts and standards. For this purpose, first, the increasing importance of digital products is briefly explained. Then, the challenge created as a result of expanding trading volume of digital products are discussed in terms of accounting with suggestions for the appropriate accounting for digital products. © 2011, IGI Global.
Accurate Dictionary Matching for Mr Fingerprinting Using Neural Networks and Feature Extraction
(Institute of Electrical and Electronics Engineers Inc., 2020-10-05) Soyak R.; Ersoy E.O.; Navruz E.; Fakultesi M.; Unay D.; Oksuz I.; Ersoy, Eda Ozgu; Unay, Devrim; Navruz, Ebru; Fakultesi, Muhendislik; Soyak, Refik; Oksuz, Ilkay
Magnetic Resonance Fingerprinting is a recent technique which aims at providing simultaneous measurements of multiple parameters. MRF works by varying acquisition parameters in a pseudorandom manner so as to get unique, uncorrelated signal evolutions from each tissue. MRF is a dictionary based approach, and thus requires a database. This database can be created by simulating the signal evolutions from first principles using different physical models for a wide variety of tissue parameter combinations. Having this dictionary, a pattern recognition algorithm is used to match the acquired signal evolutions from each voxel with each signal evolution in the dictionary. In this paper, we compare the efficiency of deep learning based feature extraction method and neural network architectures in order to achieve state-of-the-art accuracy in dictionary matching for MRF. Our results showcase successful dictionary matching with high accuracy both quantitatively and qualitatively. © 2020 IEEE.
Acoustic Emission Response of Macro Synthetic Fibre Reinforced Concrete Beams
(Natl Inst Science Communication-Niscair, 2025) Selman, Efe; Kilic, Gokhan
Macro synthetic fibre reinforced concrete(MSFRC) has been frequently preferred owing to their adequate ductility, post cracking capacity and toughness values, being potential sustainable alternative material to steel fibre concrete. Their fracture processes and possible failure mechanisms have been simultaneously scrutinized in order to fully exploit from their advantageous structural characteristics. AE methods have accurately provided comprehensive information on the origination and development of a flaw that is located in inner sections of material. With this current study, AE technique has been selected in order to determine the crack evolution and propagation in MSFRC structures. To study the AE response of MSFRC specimens, three MSFRC specimens in the volumetric ratios 0.5%,1% and 1.5% have been prepared and tested with reference concrete specimen. Average frequency, RA(Rise time to Amplitude ratio) and Sentry function parameters have been examined during three-point bending tests for specimens. AE features which correspond to the damage occurrences have been identified and shown during load history. AE method has been found to predict adequately the damage progression of MSFRC elements and the experimental behaviours of specimens have been typically captured well.
Citation - WoS: 6
Citation - Scopus: 5
Acrylamide-Encapsulated Glucose Oxidase Inhibits Breast Cancer Cell Viability
(Walter De Gruyter Gmbh, 2020-08-04) Rrustemi, Trendelina; Geyik, Oyku Gonul; Ozkaya, Ali Burak; Ozturk, Taylan Kurtulus; Yuce, Zeynep; Kilinc, Ali
Objectives: Cancer cells modulate metabolic pathways to ensure continuity of energy, macromolecules and redoxhomeostasis. Although these vulnerabilities are often targeted individually, targeting all with an enzyme may prove a novel approach. However, therapeutic enzymes are prone to proteolytic degradation and neutralizing antibodies leading to a reduced half-life and effectiveness. We hypothesized that glucose oxidase (GOX) enzyme that catalyzes oxidation of glucose and production of hydrogen peroxide, may hit all these targets by depleting glucose; crippling anabolic pathways and producing reactive oxygen species (ROS); unbalancing redox homeostasis. Methods: We encapsulated GOX in an acrylamide layer and then performed activity assays in denaturizing settings to determine protection provided by encapsulation. Afterwards, we tested the effects of encapsulated (enGOX) and free (fGOX) enzyme on MCF-7 breast cancer cells. Results: GOX preserved 70% of its activity following encapsulation. When fGOX and enGOX treated with guanidinium chloride, fGOX lost approximately 72% of its activity, while enGOX only lost 30%. Both forms demonstrated remarkable resilience against degradation by proteinase K and inhibited viability of MCF-7 cells in an activity-dependent manner. Conclusions: Encapsulation provided protection to GOX against denaturation without reducing its activity, which would prolong half-life of the enzyme when administered intravenously.
Citation - Scopus: 2
Activating Co-Creation Methodologies of 3d Printing With Biocomposites Developed From Local Organic Wastes
(Education and research in Computer Aided Architectural Design in Europe, 2022) Afsar S.; Estevez A.T.; Abdallah Y.K.; Turhan G.D.; Oze B.; Doyuran A.; Doyuran, Aslihan; Turhan, Gozde Damla; Estevez, Alberto T.; Afsar, Secil; Oze, Berfin; Abdallah, Yomna K.; Ozel, Berfin
Compared to the take-make-waste-oriented linear economy model, the circular model has been studied since the 1980s. Due to consumption-oriented lifestyles along with having a tendency of considering waste materials as trash, studies on sustainable materials management (SMM) have remained at a theoretical level or created temporary and limited impacts. To ensure SMM supports The European Green Deal, there is a necessity of developing top-down and bottom-up strategies simultaneously, which can be metaphorized as digging a tunnel from two different directions to meet in the middle of a mountain. In parallel with the New European Bauhaus concept, this research aims to create a case study for boosting bottom-up and data-driven methodologies to produce short-loop products made of bio-based biocomposite materials from local food & organic wastes. The Architecture departments of two universities from different countries collaborated to practice these design democratization methodologies using data transfer paths. The 3D printable models, firmware code, and detailed explanation of working with a customized 3D printer paste extruder were shared using online tools. Accordingly, the bio-based biocomposite recipe from eggshell, xanthan gum, and citric acid, which can be provided from local shops, food & organic wastes, was investigated concurrently to enhance its printability feature for generating interior design elements such as a vase or vertical gardening unit. While sharing each step from open-source platforms with adding snapshots and videos allows further development between two universities, it also makes room for other researchers/makers/designers to replicate the process/product. By combining modern manufacturing and traditional crafting methods with materials produced with DIY techniques from local resources, and using global data transfer platforms to transfer data instead of products themselves, this research seeks to unlock the value of co-creative design practices for SMM. © 2022, Education and research in Computer Aided Architectural Design in Europe. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Active Vibration Control of Cantilever Structures by Integrating the Closed Loop Control Action Into Transient Solution of Finite Element Model and an Application To Aircraft Wing
(Mdpi, 2025-04-30) Bulbul, Ilker; Akdag, Murat; Karagulle, Hira
In this study, the active vibration control (AVC) of a cantilever beam with an end mass is considered first and studied experimentally and through simulation. The Laplace transform method, Newmark method, and ANSYS are used for simulations. An impulse force applied to the mass and the velocity actuation applied to the base are assumed to be disturbance and controlling input, respectively. The displacement of the mass is taken as the feedback signal in simulations. Four strain gauges are located near the bottom point, connected with a Wheatstone bridge, and the output voltage of a load-cell amplifier (LCA) is used as the feedback signal in experiments. Strain feedback is considered in experiments because it is easy to implement, cost-effective, and can be used in applications. Experimental displacement signals obtained from the top of the beam are compared with the output signals from LCA and it is observed that they are approximately linearly dependent. Velocity input is generated with a servo motor-driven linear actuator in experiments. The closed loop control is achieved by a personal computer with an Adlink-9222 PCI DAQ card and a C program in the experiments. The integration of the closed loop control action into the transient solution with Newmark method and ANSYS is implemented in simulations. The input reference value is taken as zero for vibration control. The instantaneous value of the feedback signal at a time step is subtracted from zero to find the error signal value and the error value is multiplied by the control gain to calculate the controlling signal. The simulation results obtained with the Newmark method and ANSYS are in good agreement with the analytical results obtained with Laplace transform method. Simulation results are also in acceptable agreement with the experimental results for explaining the behavior of the success of AVC depending on the control gain, Kp. After verifying ANSYS solutions, the ANSYS procedure is applied to an aircraft wing as a real complex cantilever structure. The wing, with a length of 810.8 mm, 13 ribs with a length of 300 mm, and NACA 4412 airfoil, is considered in this study. It is observed that the AVC of real engineering structures can be simulated by integrating control action into transient solution in ANSYS.
Citation - WoS: 23
Citation - Scopus: 31
Activity-Based Costing Approach in the Measurement of Cost of Quality in Smes: a Case Study
(Routledge Journals, Taylor & Francis Ltd, 2013-04) Ozkan, Serdar; Karaibrahimoglu, Yasemin Zengin
Since the 1950s, a considerable amount of attention has been given on the cost of quality (CoQ) in theory and in practice. Overall, it is argued that a precise measurement of the CoQ requires a well-established accounting system that provides accurate cost information. However, in the literature, it is generally considered that traditional cost accounting methods do not provide accurate cost data for the measurement of quality costs. Therefore, the aim of this study is to explore the role of activity-based costing (ABC) in supporting the measurement of CoQ in small and medium-sized enterprises in order to discuss the results of implementation, its benefits and drawbacks. Overall, it was found that the use of ABC in the CoQ measurement provides the organisation with the means to determine both value-added and non-value-added quality-related activites and to detect improvement opportunities in the production process.
Actuation and Sensor Issues: Portable CPR Machine
(Institute of Electrical and Electronics Engineers Inc., 2025-10-26) Dulger, L. Canan; Gulek, T.; Eroglu, D.; Kizil, Melahat; Gunes, M.G.; Uzsen, A.; Karaaslan, B.
A portable CPR (cardiopulmonary resuscitation) B machine is designed as a prototype. A nonlinear viscoelastic model is used to consider the human thoracic properties. Based on the mechanical movements and force-acceleration accruals associated with CPR deployment. The system model is studied for the chest response to CPR by considering the viscoelastic properties of the rib cage and intrathoracic organs. It is then numerically simulated in MATLAB/Simulink. Actuation and sensor integration details are discussed. A DC motor is applied for driving the slider crank mechanism.
Citation - WoS: 14
Citation - Scopus: 13
Adaptation of Local Businesses To the New Era During the Covid-19 and the Russia-Ukraine War: Case of Cesme
(Routledge Journals, Taylor & Francis Ltd, 2023-04-20) Nazli, Murat
Turkey's economic impact has been severe due to the lack of international tourists and the Covid-19 pandemic. Specifically, the tourist destination cesme has suffered economic fluctuations due to decreased international visitors, the Russia-Ukraine war, and insufficient domestic tourists to fill the gap. The study aims to identify deficiencies that help stakeholders manage tourism development amid Covid-19 and the Russia-Ukraine war. The data were collected through semi-structured interviews (n = 34) with local business owners operating for at least 25 years. The study provides insights into the recent tourism development during the pandemic and presents a high level of resilience among local businesses. The business owners perceive the current pandemic and the Russia-Ukraine war situation differently psychologically. Most resilient business owners look for business opportunities by adapting their business models for long-term survival despite the pandemic and the Russia-Ukraine war affecting international tourism.
Citation - WoS: 5
Citation - Scopus: 6
Adaptation of Quality of Life Measure for Limb Lymphedema-Arm in Turkish Women With Breast Cancer-Related Lymphedema
(Lippincott Williams & Wilkins, 2019-08-30) Karayurt, Ozgul; Deveci, Zeynep; Eyigor, Sibel; Inbat, Menekse Ozgur; Özgür nbat, Menekse
Background Quality-of-life measures are needed for clinicians and researchers to identify quality of women's life with breast cancer-related lymphedema (BCRL). Objective To adapt Quality of Life Measure for Limb Lymphedema-Arm into Turkish (TR) and to test its validity and reliability. Methods This is a methodological and cross-sectional study and was conducted in the lymphedema outpatient clinic of a university hospital. The study included 109 women with BCRL. After linguistic validity of the scale was achieved, confirmatory factor analyses and known group validity were used to test its construct validity. Reliability of the scale was tested with Cronbach's alpha, item-total correlations, and Spearman-Brown coefficient. Results After linguistic validity was achieved, opinions requested from 5 experts specializing in lymphedema showed that item and content validity indexes of the scale were 1. Fit indexes of confirmatory factor analysis were as follows: chi(2)/df = 1.86, root mean square error of approximation = 0.089, standardized root mean square residual = 0.09, and comparative fit index = 0.81. Known group validity analysis showed a significant difference in the mean scores for the subscales of Quality of Life Measure for Limb Lymphedema-Arm-TR, symptom, function, and body image/appearance in terms of lymphedema stages (P < .05). The internal reliability coefficients for the subscales ranged from 0.78 and 0.86. The item-total correlation coefficients ranged between 0.36 and 0.73. Conclusion Quality of Life Measure for Limb Lymphedema-Arm-TR was found to be valid and reliable in the TR population. It could be used in research to evaluate the quality of life in patients with BCRL. Implications for Practice The scale can be used to evaluate effectiveness of nursing interventions directed toward patients developing breast cancer-related lymphedema in clinical settings and studies.
Adaptive business device integration architecture: Event manager
(2010) Ünlütürk, Mehmet Süleyman; Kurtel, Kaan
Today's heterogeneous business environments are complex and highly collaborative in which several different types of business events shape. Many devices that coexist in the same business environment generate these events, and this situation requires better integration and real-time communication solutions. We propose a fully integrated communications network solution called Integrated Event Management System (IEMS) that provides a range of mechanisms to meet the individual requirements of the business environments. IEMS is a software product designed to improve the quality and management of any heterogeneous business environment such as Hospital Nurse Call System (HNCS). The functionality of this network is invaluable to offer communication solutions to everyone in the system. Some of those do not have fixed locations such as mobile personnel that are dependent on being alerted immediately anywhere. Furthermore, IEMS also provides protection for others that work in interview rooms. An alarm event can be sent to a team over Local Area Network (LAN), alerting them of an incident and the location in order to provide a rapid response.
Citation - WoS: 14
Citation - Scopus: 18
Adaptive Controller Based on Grid Impedance Estimation for Stable Operation of Grid-Connected Inverters Under Weak Grid Conditions
(Inst Engineering Technology-Iet, 2020-09-02) Temiz, Hakan; Keysan, Ozan; Demirok, Erhan
An electric grid having high impedance seen from the connection point is considered as a weak grid and it adversely affects the system stability of grid-tied voltage source inverters in renewable power devices. In this study, an adaptive controller is proposed by configuring the settling time of the phase-locked loop based on the estimated grid impedance. Pseudorandom binary sequence injection and Fourier techniques are carried out for grid impedance estimation. Impedance-based stability analysis is performed for a predetermined steady-state operation point. The proposed method is verified by a 300-kVA inverter prototype for wide-range grid impedance varying from 0.3 to 3 mH.
Citation - WoS: 1
Citation - Scopus: 2
Adaptive Evolution of Finite State Machines for the Tartarus Problem
(Institute of Electrical and Electronics Engineers Inc., 2019-10) Oguz K.; Oguz, Kaya
Genetic algorithms can be used to evolve finite state machines for problems that require a large number of states and transitions. Tartarus problem is such a problem in which the purpose is to push the boxes towards the walls of a six by six grid using a bulldozer that can only sense its 8-neighbourhood. The bulldozer can rotate left, right, or move forward, each taking a single move out of its initial 80 moves. The result is scored by the number of boxes that are against a wall when the bulldozer is out of moves. Several approaches have been proposed, with genetic algorithms being the most common. We are proposing a representation of the problem using varying number of states and adaptive modification of the mutation parameter to decrease the probability of the population getting stuck at a local minima. Our results show improvement over the application of the genetic algorithm without parameter modification and dependency on the number states and the size of the population. © 2019 IEEE.

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