Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(66)
- Merdan, Mehmet(56)
- Duran, Celal(50)
- Ozdes, Duygu(47)
- Kaygusuz, Abdullah(42)
- Demir, Selim(37)
- Turan, Ibrahim(37)
- Ashyralyyev, Charyyar(34)
- Dokuz, Abdurrahman(33)
- Araz, Onur(31)
- Öztürk, Serkan(31)
- Sipahi, Ferkan(30)
- Kandemir, Raif(28)
- Arslan, Mehmet(27)
- Karsli, Orhan(27)
- Kulakaç, Nurşen(26)
- Baltacı, Cemalettin(25)
- Gücer, Mehmet Ali(25)
- Kurt, Kemal(25)
- Maden, Nafiz(25)
- Ozturk, Samet(25)
- Topal, Fevzi(25)
- Baltaci, Cemalettin(24)
- Yücel, Cem(24)
- Aliyazicioglu, Yuksel(23)
- Bayrakdaroglu, Serdar(23)
- Kankal, Murat(23)
- Peker, Iskender(23)
- Yolcu, Halil(23)
- Reis, Hatice Catal(21)
- Topal, Meryem(21)
- Vural, Alaaddin(21)
- Aydin, Aydanur(20)
- Aydin, Faruk(20)
- Bayraktar, Alemdar(20)
- Kurnaz, Muammer(20)
- Çelik, Necati(20)
- Ürkek, Bayram(20)
- Cakir, Tufan(18)
- Günen, Mehmet Akif(18)
Yayınlar
- MakaleAçık Erişim2018Scopus SJRQ1The effects of ownership concentration and institutional distance on the foreign entry ownership strategy of Turkish MNEs
Ilhan-Nas, Tulay; Okan, Tarhan; Tatoglu, Ekrem; Demirbag, Mehmet; Glaister, Keith W.
We investigate how ownership concentration and institutional distance both directly influence the equity-based ownership strategies of a sample of Turkish MNEs, and also how institutional differences moderate the link between ownership concentration and the equity-based ownership strategies of these firms. The findings suggest that neither ownership concentration nor institutional distance significantly affects the level of equity ownership. Although institutional distance variables have no direct effects on equity ownership, they tend to moderate the relationships between the ownership concentration and foreign equity ownership strategy of Turkish MNEs. In particular, we provide evidence that the regulative and normative dimensions of institutional distance affect the strength of the relationships between equity ownership strategy of MNEs and ownership concentration more so than the cognitive dimension of institutional distance.
AtıfScopus37WoS38OpenAlex42
İncele - MakaleAçık Erişim2018Scopus SJRQ3PRODUCTION OF STRUCTURED LIPIDS FROM HAZELNUT OIL WITH CONJUGATED LINOLEIC ACID BY LIPASE-CATALYZED ESTERIFICATION: OPTIMIZATION BY RESPONSE SURFACE METHODOLOGY
Bakir, N.; Ilyasoglu, H.; Yucetepe, A.; Kasapoglu, K. N.; Demircan, E.; Ozcelik, B.
The aim of this study was to synthesize structured lipid from hazelnut oil with conjugated linoleic acid (CLA) by lipase-catalyzed esterification reaction. The incorporation of CLA into hazelnut oil was optimized by response surface methodology (RSM). Substrate molar ratio, time, and temperature were independent variables chosen for optimization of the reaction. Substrate molar ratio was the most significant variable on the incorporation of conjugated linoleic acid. Good quadratic model was achieved by multiple regression analysis and backward elimination. Optimal incorporation conditions were determined as follows: reaction temperature, 59 degrees C; time, 6 hours; substrate molar ratio, 4. Under these optimum conditions, a maximum incorporation ratio of CLA into hazelnut oil of 49.42% was achieved.
AtıfScopus1WoS1OpenAlex3İncele - Derleme MakaleAçık Erişim2018Scopus SJRQ3A REVIEW OF FLOW BOILING IN MINI AND MICROCHANNEL FOR ENHANCED GEOMETRIES
Çebi, Alican; Celen, Ali; Donmez, Aydin Haci; Karakoyun, Yakup; Celen, Pinar; Cellek, Mehmet Salih; Dalkiliç, Ahmet Selim; Taner, Tolga; Wongwises, Somchai
Flow boiling researches in enhanced geometries practiced recently have been summarized in this review. Classical approximations in macroscale flows have not applied to the flows with small hydraulic diameters, so, this subject has been paid attention by the researchers. Application areas of these structures are increasing continuously due to cooling need in small confined spaces. The related studies have been reviewed in a chronological manner and their parameters have been given in a table in order for the researchers to observe the scientific duration regarding the progresses on this subject. Almost all papers on this subject have been produced after 2000, therefore, this subject is considered as an actual one to improve and worth to study in the literature. This study can not only be evaluated as the beginning argument for the researchers involved in flow boiling process in mini and microchannel, but it also consists of new works on the investigated subject.
AtıfScopus35WoS30OpenAlex33TR Dizin4
İncele - MakaleYalnız künye2018Scopus SJRQ2Automatic extraction of sparse trees from high-resolution ortho-images
Bayram, Bulent; Seker, Dursun Zafer; Jamil, Akhtar; Reis, Hatice Catal; Demir, Nusret; Bozkurt, Salih; Ince, Abdulkadir; Kucuk, Turgay
Obtaining information about tree species distribution in agricultural lands is a topic of interest for various applications, such as tree inventory, forest management, agricultural land management, crop estimation, etc. This information can be derived from images obtained from modern remote sensing technology, which is the most economical way as compare to field surveys covering large geographic areas. Therefore, in this study, a new method is proposed for extraction and counting of sparse and regular distributed individual pistachio trees from agricultural areas on large scale from high-resolution digital ortho-photo maps, which were obtained using an airborne sensor (Ultracam-X). The input images were first smoothed by applying Gaussian filter to reduce the impact of noise. Normalized difference vegetation indices (NDVI) were then derived to obtain vegetation areas followed by Otsu's global thresholding algorithm to obtain candidate tree areas. Further, connected component (CC) analysis was applied to segregate each object. Morphological processing was performed to fill holes within tree objects and get smooth contours, which were obtained by using the Moore-neighbor tracing method (MNTM) for each CC, while geometrical constraints were applied to undermine possible non-tree elements from output image. To further improve the segmentation results for sparse trees, a new method was applied, called quadratic local analysis (QLA). QLA helped to segment the trees, which were missed by the Otsu method due to low contrast and resulted in improved accuracy (3-6%). The obtained results were compared with well-known support vector machine (SVM) classifier. Proposed method produced slightly better results (1-5%) than SVM for extraction of pistachio trees and obtained accuracy for QLA and SVM were 96 and 91% for region 1, while 91 and 90% for region 2 respectively.
AtıfScopus3WoS2OpenAlex3İncele - BildiriYalnız künye2017Real Time Sending and Monitoring Electronic Health Records
Dogan, Ramazan Ozgur; Kayikçioglu, Temel; Yagci, Yavuz
Innovations in the field of health increase with the developing technology nowadays. These technological advances in the health field have enabled us to meet with telemedicine applications. Telemedicine is the use of computer technologies and the Internet infrastructure so that we can access health services without going to the hospital. In telemedicine applications, patients can access past electronic health records of patients can be accessed as well as access real-time instant electronic health records is provided. Real-time telemedicine applications usually aim to provide remote access to the biological signs of the patient and to diagnose them through these signals. In this study, it is mentioned how a real time telemedicine application can be performed, which features should be provided, and which performance criteria should be taken into consideration while developing. In addition, performance values are examined for a sample implementation.
- MakaleYalnız künye2017Mathematical modeling of thin-layer microwave drying of corn husk and investigation of powder properties
Akdogan, A.; Koç, G. Caliskan; Dirim, S. N.
The aim of this study is to investigate the effect of different microwave powers on the drying kinetics of chopped corn husks and to determine the properties of the corn husk powder obtained after grinding the dried product. The drying behavior of corn husks was determined using eleven commonly used thin-layer models. The obtained powders were analyzed for moisture content, water activity, color, tapped and bulk densities, wettability, flowability, and cohesiveness. In addition, the effective moisture diffusivity and activation energy of corn husks were calculated from drying data. From the analysis of the results, the drying rate and the drying time of corn husk slices considerably decreased with increasing microwave power. Among all used drying models, the Page model was found to satisfactorily describe the kinetics of microwave drying of corn husk. The effective moisture diffusivity values ranged from 2.264x10(-10) to 8.941x10(-10) m(2)s(-1).
AtıfWoS2İncele - BildiriYalnız künye2017Observing the Entropy of Crowd Movements
Akpulat, Murat; Ekinci, Murat
Providing security and managing it as well as trying to understand how it behaves have become an important research topic in our day. The aim of this study is to calculate the entropy value of the crowd movement regionally and to track how it. changes in time. Because, excessive changes in the entropy value in time might point to abnormal behaviour in the region. The motion information obtained from the optical flow method from the image in parallel to the target was converted to motion orbits by particle advection. Motion orbits are mapped into by the Braid Theory and entropy value is calculated. Braid Theory is a mathematical method that is used to express entropy as a qualitative value by determining the interaction among the movement orbits. The results are tested according to the video sequence in the PETS2009 and UCF database and they show that this method is functional for observing how the entropy changes in time within the crowd movement.
- BildiriYalnız künye2017Hardware Friendly Early Stopping Structure For Polar Code
Simsek, Cemaleddin; Albayrak, Cenk; Türk, Kadir
Polar code has become a major milestone in information theory field in recent times. Researchers are still observing more efficient encoding and decoding structures. In this study, a new WIB based structure is proposed which reduces the computational complexity of WIB introduced as an early termination method for BP polar decoder in literature. Both proposed and WIB methods are implemented with VHDL and hardware complexities are compared via XILINX ISE synthesis tool. Most important complexity reduction came with removing unnecessary addition operations which make early termination method possible to implement only with hit-wise logical operations. Results show that along with complexity reduction proposed approach can also acquire same performance in half time compared to previous counterpart with fewer logic gates.
- MakaleYalnız künye2017Chemical composition and bioactive properties of the essential oil of Rhinanthus angustifolius subsp grandiflorus
Kaya, A. A.; Üçüncü, O.; Ilter, S. M.; Baltaci, C.; Öztürk, S.
In this study, the chemical composition and antimicrobial activities of the essential oil of the Rhinanthus angustifolius subsp. grandiflorus plant were investigated. Essential oil was obtained from all parts of the plant by hydrodistillation and was analyzed by GC-FID and GC-MS. 31 components representing 99.46% of the total oils were characterized. The main components of these species were found to be 2,3-dihydro-5-methyl-1H-indene (25.14%), alpha-cubebene (19.27%), 1-hexadecene (15.59%) and hexadecanoic acid (12.14%). The antimicrobial activity of the isolated essential oil was investigated. Antimicrobial activity was observed against B. cereus, E. coli, E. coli O157:H7 and S. Aureus microorganisms. Moreover, an effect on the ferments of B. cereus, E. coli, E. coli O157:H7 and S. Aureus was detected.
AtıfWoS4İncele - MakaleAçık Erişim2017Calculation of the Index of Turkey's Vulnerability in Natural Disasters
Bostan, Sedat; Yaprak, Unal
Aim: The aim of this study was to determine the vulnerability levels of Turkey in terms of natural disasters and to guide decision makers and strategists in this field. In the study, disaster data obtained for 1987-2011 were used, and the disaster of type was most observed in our country. Materials and Methods: Data vulnerability indices against the disasters were calculated using a Data Envelopment Analysis Program (DEAP) 2.1 program with a Data envelopment analysis-based output-oriented Malmquist Total Factor Productivity Index method. Results: The regions of Turkey, which have the highest vulnerability index for the disasters, were TRA2 (0.323), TRB2 (0.305), and TRB1 (0.287) regions. In addition, it was seen that in the Black Sea region, the TR82 (0.267) region was more vulnerable than the other places of the region. In this study, a picture of the whole country over a period of 25 years in terms of disasters was captured. Conclusion: In the picture, it is seen that economic and social costs endured due to disasters are separated into two regions starting from the region of Eastern Anatolia and the north branch extends across the Black Sea region and the other south branch reaches to the Mediterranean.
AtıfOpenAlex1İncele - MakaleYalnız künye2017THE USABILITY OF VOLCANIC ROCKS FROM UPPER EUPHRATES PART IN THE EASTERN ANATOLIA REGION AS CONCRETE AGGREGATE
Aksüt, Yavuz Selim; Yetgin, Sukru
In this study; the engineering properties of volcanic rocks obtained from four different quarries in the province of Erzincan region in the Upper Euphrates Part in the Eastern Anatolia Region were investigated. In laboratory studies, the experiments including bulk and aggregate tests (bulk and dense unit weight, specific mass, water absorption, Los Angeles test for resistance to wear, freezing resistance and uniaxial compressive strength) were conducted on 5 volcanic samples according to the standards (Turkish Standard, British Standard and ASTM) and in the second stage, grading of concrete tests (grading of the concrete aggregates, concrete preparation, slump test, specific density of concrete, uniaxial compressive strength, modulus of elasticity, splitting tensile strength, abrasion resistance and capillarity) were performed on the concrete samples with volcanic aggregates. For fresh concrete composition, water/cement ratio was selected as the main variable providing homogeneous mixing and the highest strength to the concrete samples with a specific granulometry. Cylindrical concrete samples were produced with a variety of water/cement ratios cured for 7 and 28 days in water and their compressive strengths were assessed in the light of their physical and mechanical properties. The results obtained from aggregates and concrete tests, which were performed in line with the standards showed that especially Yassitepe-Dogu (YTD) sample, one of the volcanic rocks from Erzincan region can be used as concrete aggregate. It was observed that compressive strength of the concrete samples could satisfy C25/30 strength class and upper classes. In addition, it was understood that they can be used in highways, bridges, dams, buildings etc., especially as structural concrete.
AtıfWoS1İncele - MakaleAçık Erişim2017Reconsideration of Orhon Inscriptions in the context of Cultural Memory of Turkish Society: The Body and Memory of Stone
Demir, Sertac Timur
This paper aims to deal with the Orhon Inscriptions among the concepts and debates on cultural memory for the purpose of 'remembering', 'adaptation', 'updating' and 'refunctionalising' through the television documentary Time Traveller: Following the Steps of the Turks. What do the inscriptions tell us about today? What does deducing, analysing and developing a methodology for this provide to the national heritage under the titles of past, identity, belonging and memory? In this article, accordingly, cultural memory questions and suggestions are offered through the Orhon Inscriptions. Documents and documentaries, without doubt, are instruments of interpreting the past and projecting the future. This research is conceptual as well as methodological. In this respect, a minimal cultural memory glossary is fictionalised and thus a sort of conceptual ground is generated.
AtıfOpenAlex2İncele - MakaleAçık Erişim2017Reflections of the Terrorist Attacks in 2016 on Humor Magazines
Türten, Elif
Cartoon and politics have been in close relationship throughout the history of the press. Political structure of the period, social events that developed due to the political or political events that took place at that time and political actors are reflected on the caricatures and humor magazines. In our country, the year 2016 was very intense in terms of agenda. 27 terrorist attacks took place throughout 2016. During these attacks, hundreds of people lost their lives and thousands were injured. In the study, it was investigated how the terrorist incidents in 2016, which the country experienced in a state of mourning, were handled in the humor magazines, how much space was provided and how the terrorist incidents were evaluated. In this regard, the research question is set as how the political trends and ideological structures of the humor magazines that are the subject of study are reflected in the cartoons. In this context, cover pages of Penguin, Girgir and Uykusuz Magazines were used as a method of critical discourse analysis by Teun van Dijk. These magazines were selected because they constitute important examples of political cartoons and have a large reader base in Turkey. As a result of the examination, 8 cover pages were drawn in Penguen Magazine, 6 in Girgir Magazine and 7 in Uykusuz Magazine. A total of 21 cover pages were examined in the study. The Penguen Magazine approached at people who were exposed to terrorist incidents. Girgir Magazine criticized the events. However, the most serious criticism about the subject was made by Uykusuz Magazine. In general, disappointment from terrorist events has found place in cartoons.
- MakaleYalnız künye2017Scopus SJRQ3EXPERIMENTAL INVESTIGATION THE EFFECTS OF ETHANOL AND DIETHYL ETHER ADDITION INTO DIESEL FUEL ON ENGINE PERFORMANCE AND EXHAUST EMISSIONS
Sezer, Ismet
In this study, effects of ethanol and diethyl ether addition into diesel fuel on the performance and emissions of a diesel engine were experimentally investigated. A commercial diesel fuel and three different blends prepared with 15% ethanol, 15% ethanol and 2% diethyl ether and 15% ethanol and 4% diethyl ether were used in the tests. The experiments were performed at an engine speed of 1500 rpm and under various loads by using a single cylinder direct injection diesel engine. The injection, combustion, performance and emissions parameters were evaluated for baseline fuel and blends. The results show that, the injection pressure decreases for all blends, and diethyl ether addition causes a delay in the injection timing. The burnt mass fraction is lower for ethanol and diethyl ether blends during early combustion phase, while it increases for diethyl ether blends during the progressive combustion phase. Ethanol and diethyl ether blends also give the reductions in the cylinder pressure and temperature. Air excess coefficient increases the rate by 9.3-10.4%, but exhaust gas temperature decreases the rate by 4.8-5.5% when using ethanol and diethyl ether blends. Although ethanol blend causes a decrement of 1.4% in engine power, reductions in engine power are between 0.3% and 1.1% for diethyl ether blends. Both ethanol and diethyl ether blends yield increments the rate by 14.7-17.2% in brake thermal efficiency and a reduction of 8.5% in brake specific fuel consumption. The reductions were obtained the rate by 6.8-18.2% for NOx and 10.3-13.8% for CO2 emissions, when using the blended fuels. Ethanol and diethyl ether blends cause the increments the rate by 5-12.5% for HC emission, while CO emission fluctuates depending on the engine load.
AtıfWoS5İncele - MakaleYalnız künye2017MUSHROOM MANAGEMENT APPROACH
Kiliç, Taskin; Olgun, Hatun
The concept of Mushroom Management has been involved in the management science in recent years and is named after the metaphor of raising mushrooms. Just as mushrooms are fertilized, left in the dark and cultivated in a short time; mushroom managers also provide the necessary business resources to employees, however, they do not share the policies, revenues of the organization and business risks with them. The objective of study is to embrace and examine the concept of mushroom management theoretically, develop an assessment instrument for determining this perception and bring the concept and the scale in the Turkish literature. The theoretical part was formed by using the limited number of studies in literature. Field study was conducted by applying a questionnaire to 200 employees at a private health institution in the province of Trabzon with the help of an 8 point Likert scale, which was developed for measuring the concept of mushroom management. The acquired data were analyzed by using the SPSS and LISREL softwares. It was determined that study participants had moderate level of mushroom management perception. 58% of employees who participated in the study stated that the management did not establish a direct communication with junior employees and share all the information about the organization. On the other hand, a Turkish scale of eight items measuring the mushroom management perception was developed within the scope of this study. Besides, as mushroom management contains total opposite applications of open, democratic, participative and transparent management applications; it is perceived as a negative approach. However, it might turn into a useful means for managers in some cases (like preventing chaos, preserving the organization's confidentiality) in practice.
- MakaleYalnız künye2017Scopus SJRQ1The efficiency of bedside ultrasonography in patients with wrist injury and comparison with other radiological imaging methods: A prospective study
Oguz, Ahmet Burak; Polat, Onur; Eneyli, Muge Gunalp; Gulunay, Behnan; Eksioglu, Merve; Gurler, Serdar
Study objective: Our aim was to determine the efficiency of ultrasound (US) scanning in patients with wrist trauma admitted to the emergency department and to compare US diagnostic usagewith other radiological imagingmethods. Methods: Patients who presented to the emergency department with wrist injury and who met the inclusion criteria and exclusion criteria were eligible. For all patients, US evaluation of thewhole wristwas performed by an emergency physician before other radiological imagingmethods (radiographies, computed tomography (CT) and magnetic resonance (MR) imaging). All of the patients included in the study underwent US, radiography, CT, and MR. Results: During the study, 122 patients were admitted with a wrist injury. After filtering for the exclusion criteria, 80 patients were included in the study. The sensitivity of US scanning in detecting fractures was 95.31% (95% confidence interval [CI]: 87.1-98.39), the specificity was 93.75% (95% CI: 71.67-98.89), and the positive predictive value was 98.39% (95% CI: 91.72-99.85), and the negative predictive value was 83.33% (95% CI: 72.98-90.41). The sensitivity of US scanning in detecting tendon and ligamentous structural injury was 66.67% (95% CI: 41.71-84.82), the specificity was 100% (95% CI: 94.42-100), the positive predictive valuewas 100% (95% CI: 94.29-99.89), and the negative predictive was 92.86% (95% CI: 84.25-97.14). Conclusion: US scanning is an effective method that can be applied in the emergency department to adult patients to diagnose distal forearm and carpal bones fractures. In soft tissue injuries, US and MR examinations produce similar results. (C) 2017 Elsevier Inc. All rights reserved.
AtıfWoS18OpenAlex25
İncele - BildiriAçık Erişim2017Scopus SJRQ1Pressure from superiors and older age increase the risk of burnout syndrome among psychiatric trainees: A nation-wide survey in Turkey
Capraz, N.; Ozalp, D. Ceylan Tufan; Yalcin, M.; Can, E. Tellioglu; Alkin, T.
AtıfWoS2OpenAlex2İncele - MakaleYalnız künye2017Scopus SJRQ1Late Jurassic Magmatism and Stratigraphy in the Eastern Sakarya Zone, Turkey: Evidence for the Slab Breakoff of Paleotethyan Oceanic Lithosphere
Dokuz, Abdurrahman; Aydinçakir, Emre; Kandemir, Raif; Karsli, Orhan; Siebel, Wolfgang; Derman, Ahmet Sami; Turan, Mehmet
Middle-Late Jurassic Cimmerian events in Turkey have been actively discussed in the past three decades, but proposed tectonic models associated with magmatism, metamorphism, and stratigraphic features remain controversial. To address this issue, Upper Jurassic mafic lavas are investigated at three locations (Alucra, Gumushane, and Olur) in the eastern Sakarya Zone, northeastern Turkey. These lavas are submarine and form planar flows parallel with the bedding plane in the Upper Jurassic carbonate sequence near the base or just below in the clastic sedimentary rocks. The basaltic lavas show calc-alkaline features and possess Nb-Ta values and Nb/U, Nb/La, and Ce/Pb ratios that are greater than those of island arc basalts. Multielement patterns are almost hump shaped, similar to ocean island basalts, which experience Pb depletion and weak negative Nb-Ta, Zr-Hf, and Ti anomalies. The low initial (Sr-87/Sr-86) ratios (0.70372-0.70554), positive initial epsilon(Nd) values (+2.7 to +4.4), and initial Pb isotope ratios that plot between mid-ocean-ridge and ocean island basalts are consistent with a melt derived from subcontinental lithospheric mantle, metasomatized by earlier fluids from subducted sediments and plume materials from the asthenosphere. Moderate Dy/Yb ratios with an average value of 1.8 imply partial melting in the spinel-garnet transition zone at depths of similar to 70-100 km. Slab breakoff is suggested as a geodynamic mechanism that accounts for these geochemical signatures. This inference is also favored by stratigraphic and sedimentologic evidence from the Upper Jurassic-Lower Cretaceous sedimentary rocks, which is consistent with short-lived vertical (epirogenic) movements in the region. Lower-Middle Jurassic sequences are transgressive, suggesting that subduction-related extension opened a backarc basin (Neotethys) in the south of the Sakarya Zone. Upper Jurassic-Lower Cretaceous carbonates point tectonically to tranquility during carbonate deposition in the Neotethys Ocean, which seems to have been achieved by complete closure of the Paleotethys in the north. About 15-20 m.yr. later (Kimmeridgian), after first carbonate deposition, intraplate-typemafic lavas ascended up to the shelf surface of the Neotethys. This was followed by formation of disconformity surfaces and then accumulation of coarse clastic sediments. All this points to a short-lived epirogenic movement that we ascribe to the breakoff of the southward-subducting Paleotethyan oceanic lithosphere in the Late Jurassic.
AtıfWoS73OpenAlex76İncele - BildiriAçık Erişim2017Scopus SJRQ1MEDIAN AND ULNAR NERVE CROSS-SECTIONAL AREA IN CARPAL TUNNEL SYNDROME WITH EXTRATERRITORIAL SPREAD OF SENSORY SYMPTOMS
Kaplan, B. Mansiz; Leblebicier, M. Akdeniz; Yagci, I.
- MakaleYalnız künye2017Scopus SJRQ2Finite Modeling Updating Effects on the Dynamic Response of Building Models
Günaydin, M.; Adanur, S.; Altunisik, A. C.; Sevim, B.; Bayraktar, A.
An improved finite element model was used to obtain more accurate modeling of engineering structures. The main goal of this paper was to determine how this improved modeling procedure affects the dynamic response of buildings based on experimental modal parameters such as natural frequencies, mode shapes and damping ratios. For experimental assessment, three small, one-story, two-bay, reinforced concrete buildings with raft foundation were constructed under laboratory conditions. The initial three-dimensional finite element models, built with the ANSYS software, were used to analytically identify modal parameters, including natural frequencies and mode shapes. Following the analytical study, the ambient vibration tests were performed to obtain modal parameters, experimentally. The enhanced frequency domain decomposition method and the stochastic subspace identification method were used to identify the modal parameter. The analytical and experimental modal parameters were compared and then initial finite element models were updated to minimize the differences by changing of some uncertain parameters such as materials properties. With model updating, the maximum difference between the measured and initially obtained frequency was reduced from 28.47 to 4.88%. To show the model updating effect on dynamic response of building models, dynamic analysis with the experimental computed damping ratios and 5% damping ratio were carried out using 1992 Erzincan earthquake ground motion record. For the experimental damping ratios, the maximum differences in the displacements and stresses between the initial and updated models were obtained as 23 and 32%, respectively. These differences were calculated as 43 and 15 % for the 5 % damping ratio. Comparisons of dynamic analyses results for the initial and updated model show that the finite element model updating affects the dynamic response of the buildings considerably.
AtıfWoS12OpenAlex11İncele