Browsing by Author "Dogan, E"

Now showing 1 - 18 of 18
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    An improved particle swarm optimizer for steel grillage systems
    Erdal, F; Dogan, E; Saka, MP
    In this paper, an improved version of particle swarm optimization based optimum design algorithm (IPSO) is presented for the steel grillage systems. The optimum design problem is formulated considering the provisions of American Institute of Steel Construction concerning Load and Resistance Factor Design. The optimum design algorithm selects the appropriate W-sections for the beams of the grillage system such that the design constraints are satisfied and the grillage weight is the minimum. When an improved version of the technique is extended to be implemented, the related results and convergence performance prove to be better than the simple particle swarm optimization algorithm and some other meta-heuristic optimization techniques. The efficiency of different inertia weight parameters of the proposed algorithm is also numerically investigated considering a number of numerical grillage system examples.
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    A comparative analysis of metaheuristic algorithms for optimizing curved roof structures
    Üstüner, B; Aydogdu, I; Özyürek, C; Dogan, E
    This article explores the optimal design of curved steel structures with a focus on minimizing their weight by determining the most suitable cross-sections. Customized optimization algorithms were developed to identify structural designs that meet safety and durability requirements, adhering to design constraints set by the ASDAISC specification. To ensure reliable results, the study employs a variety of metaheuristic optimization methods: Biogeography-Based Optimization (BBO), Dynamic Harmony Search (DHS), Wolf Colony Algorithm (WCA), and Honey Badger Algorithm (HBA). The Honey Badger Algorithm, a relatively new addition to the field, was used for the first time in the context of structural optimization for curved roof systems. This unique approach aims to evaluate its performance in civil engineering problems and compare it with other established algorithms. The major challenges of this study lie in the inherent complexity of dome structures, which involve a large number of elements and nonlinear constraints. The subdivision of the structure into smaller groups was necessary to manage the computational load, although this introduced additional complexities. Despite these challenges, the metaheuristic methods demonstrated their robustness in addressing such intricate engineering problems. Additionally, data retrieval is facilitated through Open Application Interface (OAPI) functions, enabling seamless data transfer between SAP 2000 and Visual Basic. The study's final design example involves a dome model with 2556 elements, which was both modeled and optimized. The results demonstrate the effectiveness of these optimization algorithms in achieving structurally sound and efficient designs. The insights gained from this study contribute to our understanding of optimized cross-sections in curved steel structures, offering valuable guidance for improving structural performance and minimizing material usage.
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    The effect of motivational climate and conscientiousness on athletes' maximal voluntary contraction level of biceps brachii muscle
    Tok, S; Dal, N; Dogan, E; Yaman, Ç; Binboga, E
    We investigated the effect of induced motivational climates (a mastery climate and a performance climate) on maximal voluntary contraction (MVC) level of the biceps brachii muscle. We also aimed to explore whether motivational orientations, together with conscientiousness, are associated with MVC level in mastery and performance climate conditions. The sample consisted of 53 college student athletes ranging in age from 20 to 26. Participants first completed the Task and Ego Orientation in Sport Questionnaire and items relating to conscientiousness from the Short Form of the Five Factor Personality Inventory. Then, during isometric elbow flexion, MVCs were measured in a neutral condition. Afterwards, participants were informed of their MVC levels measured in the neutral condition via biofeedback software, and randomly assigned to either the mastery or the performance condition. Participants in the mastery climate condition were instructed to exceed their own highest MVC level observed in the neutral condition. In contrast, participants in the performance climate condition were instructed to exceed an unrealistic MVC level described as the best ever recorded so far. Results indicated that percentage change in MVC differed significantly between the mastery and performance climate conditions. Specifically, while there was a 13.5% increase in MVC value in the performance climate condition, there was an 8.8% decrease in the mastery climate condition. Results also showed that regardless of motivational climate, the percentage change in MVC was unrelated to motivational orientations and conscientiousness.
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    Taguchi-enhanced Grey Wolf Optimizer for robust design of cellular beams
    Ciftcioglu, AO; Ustuner, B; Dogan, E; Arafat, S; Hussain, A
    This research presents a comprehensive comparative analysis of optimization techniques for achieving the optimal design of cellular beams. The incorporation of gaps within cellular beams reduces the weight of the beam and increases section height, resulting in the production of lighter and stronger sections. The Taguchi method is employed to fine-tune the parameters of the Grey Wolf Optimizer, enabling the achievement of a robust design. The performance of each algorithm is evaluated through three design examples, facilitating comprehensive comparisons among the seven algorithms. Moreover, the study encompasses the modeling and analysis of optimally designed cellular beams using finite element software.
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    INVESTIGATING THE EFFECT OF JOINT BEHAVIOR ON THE OPTIMUM DESIGN OF STEEL FRAMES VIA HUNTING SEARCH ALGORITHM
    Dogan, E; Seker, S; Saka, MP; Kozanoglu, C
    This study aims to carry out the effect of beam-to-column connections on the minimum weight design of steel plane frames In the practical analysis of steel frames, end connections are assumed to be either fully restrained or pin-connected. However, experiments reveal that the real behavior is between these extremes and should be taken into account for the realistic design of structures. Hunting search algorithm is used for the automation of optimum design process. It is a numerical optimization method inspired by group hunting of animals such as wolves and lions. It is proven that it is a reliable and efficient technique for obtaining the solution of discrete structural optimization problems. Present design algorithm developed on the basis of hunting search algorithm selects w- sections for the members of semi rigid steel frame from the complete list of w- sections given in LRFD- AISC (Load and Resistance Factor Design, American Institute of Steel Construction). The design constraints are implemented from the specifications of the same code which covers serviceability and strength limitations. The selection of w-sections is carried out such that the design limitations are satisfied and the weight of semirigid frame is the minimum. In order to demonstrate its efficiency, three different steel frames are designed by the optimum design algorithm presented. The designs obtained by use of this algorithm are also compared with the ones produced by particle swarm optimization method.
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    Investigation of scaffolding accident in a construction site: A case study analysis
    Dogan, E; Yurdusev, MA; Yildizel, SA; Calis, G
    The construction sector is one of the few high-risk businesses due to occupational accidents, their rate of frequencies, and related serious consequences, sometimes even resulting in the death of individuals. Therefore, it is a vital necessity and priority for employers and employees during the course of a project to comply with occupational safety rules under any circumstances. Nothing should deter or compromise the safety of any individual working in a potential risk environment. Within the scope of this study, the analysis addresses a scaffolding accident that occurred on a construction site. Once the information about how the accident possibly happened was received, the scaffolding in question identified at the construction was kept for an investigation to carry out the corrective and renovation works. In this paper the suspended scaffoldings are firstly categorized. Then how the accident happened was examined and theorized. The examination and analysis were supported by the results. This study is intended to prevent similar accidents and establish necessary precautions as a matter of procedure.
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    MAJOR CONSTRUCTIONAL DISPUTE CAUSES IN TURKEY
    Yildizel, SA; Dogan, E; Kaplan, G; Ergut, A
    The possibility of construction disputes can be reduced, but they cannot be avoided due to the uncertain and risky nature of the building industry. Conflicts between construction parties often have very unfavourable effects, such as cost increases, poor construction quality and time extension in the schedule. Lots of studies have been carried out in order to try and avoid these disagreements. However, there are no common resolution tools or techniques due to the improving conditions and scope of contracted works. Advanced methods and dispute reasons should be fully monitored and updated for the applicable solutions. This paper discusses the current major constructional dispute reasons in Turkey. The questionnaire method was applied within the scope of this study. The questionnaire documents were randomly distributed to 80 contractors to analyse major dispute reasons in Turkey. Analysis of the questionnaire results indicates that the major current dispute causes are poor quality of performed works, delays in progress payments, inefficient site management, poorly written contracts and design mistakes.
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    Autonomic Cardiac Activity Among Novice Archers During Baseline, Shooting, and Recovery
    Tok, S; Dal, N; Zekioglu, A; Çatikkas, F; Balikçi, I; Dogan, E
    Tok, S, Dal, N, Zekioglu, A, catikkas, F, Balikci, I, and Dogan, E. Autonomic cardiac activity among novice archers during baseline, shooting and recovery.J Strength Cond Res34(9): 2627-2635, 2020-In the present study, we aimed to investigate whether heart rate variability (HRV) of novice archers may vary during baseline, shooting, and recovery periods. In addition, we aimed to explore whether HRV may have different patterns between successful and less successful archers and man and woman archers. The sample consisted of 39 (12 woman) novice archers ranging in age from 21 to 27. Baseline HRV activity was measured in the first stage of the experiment. Then, participants shot 10 arrows, from 18 m to an 80 cm diameter target, whereas their HRV was measured. Lastly, HRV recovery response was measured immediately after shooting. HRV was represented as low frequency (LF), high frequency (HF), and LF/HF ratio. When considering the entire sample, repeated measures of analysis of variance (ANOVA) indicated that only HF power differed among baseline, shooting, and recovery periods [F(2, 76) = 6.90,p= 0.002, omega(2)= 0.15]. When the data partitioned, based on the median split of the shooting scores, repeated measures of ANOVA demonstrated that none of the HRV components differed in the less successful group from baseline to recovery. However, in the successful group, both LF [F(1.47, 30.98) = 4.75,p= 0.024, omega(2)= 0.18] and HF [F(1.54, 32.37) = 6.61,p= 0.007, omega(2)= 0.24] power significantly differed among baseline, shooting, and recovery. No differences were found between man and woman archers in terms of HRV indices. The results of the present study indicated that physical activities requiring the use of perceptual motor skills, in addition to physical qualities, may lead to different HRV responses. Moreover, coaches aiming to develop archers' shooting accuracy may take into account LF power measured during an arrow shooting session.
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    Solving design optimization problems via hunting search algorithm with Levy flights
    Dogan, E
    This study presents a hunting search based optimum design algorithm for engineering optimization problems. Hunting search algorithm is an optimum design method inspired by group hunting of animals such as wolves, lions, and dolphins. Each of these hunters employs hunting in a different way. However, they are common in that all of them search for a prey in a group. Hunters encircle the prey and the ring of siege is tightened gradually until it is caught. Hunting search algorithm is employed for the automation of optimum design process, during which the design variables are selected for the minimum objective function value controlled by the design restrictions. Three different examples, namely welded beam, cellular beam and moment resisting steel frame are selected as numerical design problems and solved for the optimum solution. Each example differs in the following ways: Unlike welded beam design problem having continuous design variables, steel frame and cellular beam design problems include discrete design variables. Moreover, while the cellular beam is designed under the provisions of BS 5960, LRFD-AISC (Load and Resistant Factor Design-American Institute of Steel Construction) is considered for the formulation of moment resisting steel frame. Levy Flights is adapted to the simple hunting search algorithm for better search. For comparison, same design examples are also solved by using some other well-known search methods in the literature. Results reveal that hunting search shows good performance in finding optimum solutions for each design problem.
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    Structure Optimization with Metaheuristic Algorithms and Analysis by Finite Element Method
    Üstüner, B; Dogan, E
    In engineering, design is made by considering functionality, reliability, manufacturability, usability, and total cost. There are a wide variety of methods for design optimization. Metaheuristic methods inspired by nature are one of them. In this study, the Refinement firefly algorithm is proposed as a new method. Grey Wolf, Particle Swarm, and Firefly algorithms are compared with the proposed Refinement Firefly Algorithm. Mathematical benchmark problems are used to examine the performance of algorithms. Also, welded beam, cellular beam, and frame system designs are considered sample problems. These design examples are solved by algorithms and the sections are determined. The sections determined by optimization were analyzed using the ABAQUS CAE program and its reliability was examined. Numerical analysis with the finite element method is very useful as it provides realistic solutions. ABAQUS CAE is used to detect and show deformations in the structure. Finite element solution with ABAQUS solves the problems analytically and it is seen that the sections determined by the optimum design algorithm remain within the limits. The proposed Refinement Firefly algorithm demonstrates superior performance compared to the Firefly algorithm. However, it yields inferior results when compared to the Grey Wolf and Particle Swarm algorithms.
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    Weight optimization of steel frames with cellular beams through improved hunting search algorithm
    Dogan, E; Ciftcioglu, AO
    Hunting search method-based optimum design algorithm is presented to investigate the weight optimization of steel frames with cellular beams. Unlike practical applications where rolled sections are assigned to both the beams and columns, built-up sections are used for beams. Design specifications including the design of steel frames and that of cellular beams are taken from Load and Resistance Factor Design-American Institute of Steel Construction. The algorithm presented selects optimal W-sections to be used for the members of the unbraced plane frame from the ready section pool of the same code. In addition, number of holes and hole diameter of the beams are selected for optimal frame by the algorithm for satisfying the design constraints and making the weight of the frame to be minimum. Besides, Levy Flight procedure is also adopted to the simple hunting search method for better designs. Optimized steel frames with cellular beams are then analyzed by ABAQUS three-dimensional finite element software. The results attained from nonlinear finite element analysis of the steel frames are then taken into account for comparison with optimization outcomes. Results reveal that designing the beam members as cellular beams reduces the weight of the frame.
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    Simulation Optimization for Transportation System: A Real Case Application
    Akpinar, ME; Yildizel, SA; Karabulut, Y; Dogan, E
    Simulation applications help decision makers to give right decisions to eliminate some problems such as: create a new firm, need some changes inside a factory; improve the process of a hospital etc. In this engineering simulation study, there are two points which are used by students to arrive at the University. Initial point is the train station and the final point is the arrival point. Students' transportation is provided with buses. The main problem is to decide the number of buses by taking number of student into consideration. To be able to solve this real-life application PROMODEL pack software is used.
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    Wind Load Design of Hangar-Type Closed Steel Structures with Different Roof Pitches Using Abaqus CAE Software
    Çiftçioglu, AO; Yildizel, SA; Yildirim, MS; Dogan, E
    Structures convert the kinetic energy available in the air into potential energy which is in the form of pressure and suction forces reducing or fully stopping its motion. The potential impact of the wind depends on the geometric properties and pertinacity of a building, the angle of the wind flow, its strength and velocity. Design gains importance for tall buildings against the impact of the resonance along with the force based on pressure. Relevant calculations are made in Turkey based on the TS 498 Wind Load Velocity Criterion and this standard is currently being updated. This study develops the wind load design of hangar-type closed steel structures with different roof pitches using Abaqus CAE software.
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    Isokinetic evaluation of knee extensor/flexor muscle strength in Behcet's patients
    Durmus, B; Emre, S; Sahin, N; Karincaoglu, Y; Dogan, E; Baysal, O; Ersoy, Y; Altay, Z
    Background: Behcet's disease (BD) is an idiopathic, multisystemic, progressive disease. The purpose of this study is to compare the knee flexor and extensor isokinetic muscle strengths of Behcet's patients with that of healthy subjects. Methods: Twenty-five (13 male and 12 female) patients with BD and 25 (15 male and 10 female) healthy individuals were included in the study Velocities of 90 degrees/sec, 120 degrees/sec, and 150 degrees/sec were used for the isokinetic muscle strength testing. Patients with active inflammatory knee arthritis were excluded. Peak torque (Nm) and peak torque adjusted to body weight (%) were taken into consideration for comparison between study groups. Results: Compared to healthy controls, there was a statistically significant decrease in both the bilateral knee extensor and flexor muscle isokinetic peak torques (Nm) as well as the peak torques adjusted to body weight (%) at velocities of 90 degrees/sec, 120 degrees/sec and 150 degrees/sec in patients with BD (p < 0.05). However, there was no significant difference in the agonist-antagonist ratio of the isokinetic peak torques of knee muscles between the two groups. Conclusion: In light of these findings, we have concluded that both knee flexor and extensor isokinetic muscle strengths are lower in BD. We therefore recommend careful monitoring of patients with BD in temis of muscle strength.
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    Investigation of hematologic findings related to brucellosis in Anatolian region
    Çelik, M; Arslan, Y; Topcu, E; Sahinoglu, MS; Altindag, D; Gürbüz, E; Atalay, E; Demircan, SK; Emre, S; Kirik, Y; Atasoy, PY; Özer, D; Ipek, D; Dogan, E; Atli, SB; Kusçu, EG; Alkan, S; Çiçek, Y; Yüksekkaya, E; Aldemir,Ö; Sahin, A; Ürkmez, EY; Al, SÖ; Boran, R; Mizrakçi, SO; Demiray, EKD; Ceylan, MR; Erdogdu, H; Tekin, S
    Objectives: To investigate the prevalence of hematologic findings and the relationship between hemogram parameters and brucellosis stages in patients. Methods: This multi-center study included patients older than 16 years of age who were followed up with a diagnosis of brucellosis. Patients' results, including white blood cell, hemoglobin, neutrophil, lymphocyte, monocyte, mean platelet volume, platelet and eosinophil counts were analyzed at the initial diagnosis. Results: In this study 51.3% of the patients diagnosed with brucellosis were male. The age median was 45 years for female and 41 years for male. A total of 55.1% of the patients had acute brucellosis, 28.2% had subacute, 7.4% had chronic and 9% had relapse. The most common hematologic findings in brucellosis patients were anemia (25.9%), monocytosis (15.9%), eosinopenia (10.3%), and leukocytosis (7.1%). Pancytopenia occurred in 0.8% of patients and was more prominent in the acute phase. The acute brucellosis group had lower white blood cell, hemoglobin, neutrophil, eosinophil, and platelet counts and mean platelet volume, and higher monocyte counts compared to subacute and chronic subgroups. Conclusion: It was noteworthy that in addition to anemia and monocytosis, eosinopenia was third most prominent laboratory findings in the study. Pancytopenia and thrombocytopenia rates were low.
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    Push and Pull Factors of Why Medical Students Want to Leave Turkiye: A Countrywide Multicenter Study
    Eser, E; Cil, E; Sen Gundogan, NE; Col, M; Ozturk, ENY; Thomas, DT; Sunter, AT; Arslan, HN; Citil, R; Onder, Y; Picakciefe, M; Dede, B; Demirel, C; Aydin, N; Caglayan, C; Aker, AA; Borlu, A; Durmus, H; Can, G; Siddikoglu, E; Sumer, EH; Uygun, T; Alkoy, S; Aycan, KA; Koruk, I; Kuzan, R; Demir, LS; Hacilar, E; Sari, H; Kilinc, Z; Onal, O; Dogan, E; Emek, M; Terzioglu, R; Yapici, G; Erdal, D; Eser, S; Akman, EA; Kosan, Z; Yilmaz, S; Ayoglu, FN; Acikgoz, B; Musal, B; Suner, AF; Erdogan, A; Cilburunoglu, I; Saygun, M; Daymaz, D; Arslantas, D; Onsuz, MF; Beyhun, NE; Ustundag, MG; Ekuklu, G; Tas, FO; Abacigil, F; Oncu, S; Hidiroglu, S; Ozaydin, AN; Pirincci, E; Bulut, I; Tozun, M; Eskiocak, M; Gunel, P; Torun, SD; Yavuz, M; Hasde, M; Camur, D; Gunes, G; Kurt, B; Baysoy, NG; Bakirci, N; Demir, F; Catak, B; Ozyurda, F; Turan, M
    Phenomenon: Physician immigration from other countries is increasing as developed countries continue to be desirable destinations for physicians; however, the determinants of Turkish physicians' migration decisions are still unclear. Despite its wide coverage in the media and among physicians in Turkiye, and being the subject of much debate, there is insufficient data to justify this attention. With this study, we aimed to investigate the tendency of senior medical students in Turkiye to pursue their professional careers abroad and its related factors. Approach: This cross-sectional study involved 9881 senior medical students from 39 different medical schools in Turkiye in 2022. Besides participants' migration decision, we evaluated the push and pull factors related to working, social environment and lifestyle in Turkiye and abroad, medical school education inadequacy, and personal insufficiencies, as well as the socioeconomic variables that may affect the decision to migrate abroad. The analyses were carried out with a participation rate of at least 50%. Findings: Of the medical students, 70.7% had emigration intentions. Approximately 60% of those want to stay abroad permanently, and 61.5% of them took initiatives such as learning a foreign language abroad (54.5%) and taking relevant exams (18.9%). Those who wanted to work in the field of Research & Development were 1.37 (95% CI: 1.22-1.54) times more likely to emigrate. The push factor that was related to emigration intention was the working conditions in the country (OR: 1.89, 95% CI: 1.56-2.28) whereas the social environment/lifestyle abroad was the mere pull factor for the tendency of emigration (OR: 1.73, 95% CI: 1.45-2.06). In addition, the quality problem in medical schools also had a significant impact on students' decisions (OR: 2.20, 95% CI: 1.83-2.65). Insights: Although the percentage of those who want to emigrate definitely was at the same level as in the other developing countries, the tendency to migrate permanently was higher in Turkiye. Improving working conditions in the country and increasing the quality of medical faculties seem vital in preventing the migration of physicians.
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    Push and Pull Factors of Why Medical Students Want to Leave Türkiye: A Countrywide Multicenter Study
    Eser, E; Cil, E; Sen Gundogan, NE; Col, M; Ozturk, ENY; Thomas, DT; Sunter, AT; Arslan, HN; Citil, R; Onder, Y; Picakciefe, M; Dede, B; Demirel, C; Aydin, N; Caglayan, C; Aker, AA; Borlu, A; Durmus, H; Can, G; Siddikoglu, E; Sumer, EH; Uygun, T; Alkoy, S; Aycan, KA; Koruk, I; Kuzan, R; Demir, LS; Hacilar, E; Sari, H; Kilinc, Z; Onal, O; Dogan, E; Emek, M; Terzioglu, R; Yapici, G; Erdal, D; Eser, S; Akman, EA; Kosan, Z; Yilmaz, S; Ayoglu, FN; Acikgoz, B; Musal, B; Suner, AF; Erdogan, A; Cilburunoglu, I; Saygun, M; Daymaz, D; Arslantas, D; Onsuz, MF; Beyhun, NE; Ustundag, MG; Ekuklu, G; Tas, FO; Abacigil, F; Oncu, S; Hidiroglu, S; Ozaydin, AN; Pirincci, E; Bulut, I; Tozun, M; Eskiocak, M; Gunel, P; Torun, SD; Yavuz, M; Hasde, M; Camur, D; Gunes, G; Kurt, B; Baysoy, NG; Bakirci, N; Demir, F; Catak, B; Ozyurda, F; Turan, M
    Phenomenon: Physician immigration from other countries is increasing as developed countries continue to be desirable destinations for physicians; however, the determinants of Turkish physicians' migration decisions are still unclear. Despite its wide coverage in the media and among physicians in T & uuml;rkiye, and being the subject of much debate, there is insufficient data to justify this attention. With this study, we aimed to investigate the tendency of senior medical students in T & uuml;rkiye to pursue their professional careers abroad and its related factors. Approach: This cross-sectional study involved 9881 senior medical students from 39 different medical schools in T & uuml;rkiye in 2022. Besides participants' migration decision, we evaluated the push and pull factors related to working, social environment and lifestyle in T & uuml;rkiye and abroad, medical school education inadequacy, and personal insufficiencies, as well as the socioeconomic variables that may affect the decision to migrate abroad. The analyses were carried out with a participation rate of at least 50%. Findings: Of the medical students, 70.7% had emigration intentions. Approximately 60% of those want to stay abroad permanently, and 61.5% of them took initiatives such as learning a foreign language abroad (54.5%) and taking relevant exams (18.9%). Those who wanted to work in the field of Research & Development were 1.37 (95% CI: 1.22-1.54) times more likely to emigrate. The push factor that was related to emigration intention was the working conditions in the country (OR: 1.89, 95% CI: 1.56-2.28) whereas the social environment/lifestyle abroad was the mere pull factor for the tendency of emigration (OR: 1.73, 95% CI: 1.45-2.06). In addition, the quality problem in medical schools also had a significant impact on students' decisions (OR: 2.20, 95% CI: 1.83-2.65). Insights: Although the percentage of those who want to emigrate definitely was at the same level as in the other developing countries, the tendency to migrate permanently was higher in T & uuml;rkiye. Improving working conditions in the country and increasing the quality of medical faculties seem vital in preventing the migration of physicians.
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