WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Conference Object Covariance Features for Trajectory Analysis(Institute of Electrical and Electronics Engineers Inc., 2016) Karadeniz, T.; Maras, H.H.In this work, we aimed to demonstrate that covariance estimation methods can be used for trajectory classification. We have shown that, features obtained via shrunk covariance estimation are suitable for describing trajectories. We have arrived to the conclusion that, when compared to Dynamic Time Warping, the explained technique is faster and may yield more accurate results. © 2017 Elsevier B.V., All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Ber Anaylsis for Super Lorentz-Gaussian Laser Beams Propagating in Turbulent Media(Gazi Univ, Fac Engineering Architecture, 2013) Gokce, Muhsin C.; Gökçe, Muhsin Caner; Sari, Filiz; Ozek, Faruk; Elektronik ve Haberleşme MühendisliğiIn this work, BER-SNR variation of super Lorentz-Gaussian laser beam that propagating horizontally path in turbulent media is analyzed. Using scintillation index which is obtained by extented Huygens-Fresnel principle, BER - SNR value is calculated. Matlab program is used to show BER - SNR variation depending on link distance and beamwidth. To conclude, in short link range, super Lorentz-Gaussian beam is proven to be better link performance superior to commercially available Gaussian beam.Article Citation - WoS: 9Citation - Scopus: 10Effect of Use of Cu-Cr P/M Electrodes on Machining Performance of Electric Discharge Machining(Gazi Univ, Fac Engineering Architecture, 2015) Gulcan, Orhan; Çoğun, Can; Uslan, Ibrahim; Usta, Yusuf; Cogun, Can; Çoʇun, Can; Mekatronik MühendisliğiIn this study, the effect of use of Cu-Cr powder metal (P/M) electrodes on EDM performance outputs, namely material removal rate (MRR), electrode wear rate (EWR), mean and maximum roughness of machined surface (R-a and R-z) and workpiece surface recast layer thickness, was investigated experimentally. The Cu-Cr P/M electrodes produced at different mixing ratios, compacting pressures and sintering temperatures were used to machine SAE 1040 steel. The analyses performed have shown that the electrode material is deposited on to the work surface as a layer and the powder mixing ratio, the compaction pressure and sintering temperature affect the EDM performance outputs.Article Citation - WoS: 3Citation - Scopus: 4An Analytical Investigation of Rigid Plastic Beams Under Impact Loading(Gazi Univ, Fac Engineering Architecture, 2015) Gultop, Tekin; Gültop, Tekin; Yilmaz, Mahmut Cem; Alyavuz, Bahadir; İnşaat MühendisliğiBeams might be subjected to impact loading which is a particular type of dynamic loading during their service lives. In this study the behaviour of beams under low speed impact loading has been investigated analytically. Simply supported and fixed ended beams have been analyzed with the assumption of rigid plastic behaviour. The collapse mechanism has been assumed to emerge by the instant formation of plastic hinges, hence, a limit analysis has been performed under dynamic loading considering the conservation principles of energy and momentum. The behaviour of rigid plastic beams under impact loading has been compared to the behaviour of elastic beams under similar loading conditions.Article Citation - WoS: 7Citation - Scopus: 7Development and Experimental Investigation of Electrochemical Drilling Method Using Rotary Tube Tool(Gazi Univ, Fac Engineering Architecture, 2013) Ozerkan, H. Bekir; Çoğun, Can; Cogun, Can; Mekatronik MühendisliğiIn this study, a new hybrid electrochemical drilling (ECD) method, based on electrochemical machining in nonconventional machining processes, was developed. In the developed method, tube tool makes rotary motion together with inner through hole flushing. A small scale prototype ECD machine has been designed and manufactured to test the developed method. One of the important features of the new system is the regulation of tool feed rate using current feedback control. The Hadfield (manganese) steel, whose strain hardening behavior makes it very difficult to machine with conventional methods, and AISI 1040 steel, whose machinability is fairly good, were drilled using the prototype machine and results were compared. Workpiece material removal rate increased with the increasing machining voltage, tool rotational speed, electrolyte concentration and flushing pressure in both types of steels. Average radial overcut values increased with the rotational speed of the tool. The AISI 1040 steel hole geometries were regular than that of Hadfield steel. Experimental results showed that deep holes can be drilled successfully with the proposed hybrid ECD method.Article Citation - WoS: 4Citation - Scopus: 4Influence of the Material Properties on the Elastic-Plastic Deformation in a Heat Generating Composite Solid Cylinder(Gazi Univ, Fac Engineering Architecture, 2013) Ozturk, Ali; Gülgeç, Müfit; Gulgec, Mufit; Mekatronik MühendisliğiBased on Tresca's yield criterion and its associated flow rule, the elastic-plastic deformation of a centrally heated composite cylinder with fixed ends is investigated by considering the influence of geometric parameters as well as material properties such as yield strength, modulus of elasticity, Poisson's ratio, coefficient of thermal conduction and thermal expansion. In the study, stress, strain and displacement distributions in the composite cylinder made of elastic-perfectly plastic material are derived. Stress distribution and evolution of plastic regions in the composite are presented for different levels of heat generation in the core.Article Citation - WoS: 11Citation - Scopus: 13Levels of Organizational Alienation of Private and Public High School Teachers(Turkish Education Assoc, 2011) Eryilmaz, Arzu; Eryılmaz, Arzu; Burgaz, Berrin; Yabancı Diller BölümüThe concept of organizational alienation reflects a feeling of disappointment with career expectations and professional development as well as the disappointment over the inability to fullfill professional norms (Aiken & Hage, 1966). The aims and objectives of this study were to investigate the organizational alienation perception levels of public and private high school teachers in the central districts of Ankara, Turkey. It also aimed to determine the differences between teachers' perceptions of alienation levels in terms of some independent variables. The survey instrument factors were determined by Seeman (1959) as (I) powerlessness, (2) meaninglessness, (3) normlessness, (4) social-isolation and (5) self isolation. The participants of the study (362) were administered "The Scale of Organizational Alienation", developed by the researcher on the basis of the scales and researches obtained from the relevant literature. As a result of the study, teachers' perceptions of organizational alienation were determined at a moderate level (2.04). Finally, the highest percentages of organizational alieantion factors were identified as; "normlessness and powerlessness" whereas the lowest mean scores of organizational alienation were determined as "meaninglessness and social isolation".Article Citation - Scopus: 1Alevism in Recent Researches Written in English(Gazi Univ, Turk Kulturu ve Haci Bektas veli, 2010) Kurt, Zeynep; Yilmaz Kurt, Zeynep; İngilizce Mütercimlik ve TercümanlıkAs a religious ethnic group that covers a considerable number of Turkish population, the history of Alevis goes back to the Ottoman-Safavid conflict in the 16(th) and 18(th) centuries. The history of Alevis, however, has not been well recorded, and relevantly researched. Starting from the 1980s, and due to the developing communication technologies and globalization, it has been possible to talk about an "Alevi revival" since the 1980s. This study aims to review the large bulk of research that is done on Alevism since the 1980s. The achieved results display a deep concern with Alevis in contemporary life, their history, traditions and beliefs as well as identity and integration problems of the Diasporas.Article Citation - WoS: 8Citation - Scopus: 8Dimensions of Agitation Based on the Cohen-Mansfield Agitation Inventory in Patients With Dementia(Turkiye Sinir ve Ruh Sagligi dernegi, 2015) Altunoz, Umut; Baştuğ, Gülbahar; Ozel Kizil, Erguvan Tugba; Kirici, Sevinc; Bastug, Gulbahar; Bicer Kanat, Bilgen; Sakarya, Aysegul; Turan, Engin; Kanat Biçer, Bilgen; PsikolojiObjective: The aim of this study was to investigate the dimensions of agitation in dementia patients using the Turkish version of the Cohen-Mansfield Agitation Inventory (CMAI-T). Materials and Method: The study included 100 patients diagnosed as dementia, according to the DSM-IV-TR. The CMAI-T was administered to the patients' caregivers via face-to-face interviews. The Standardized Mini Mental State Examination (SMMSE) was used to assess cognitive functions. The severity of depression and the functional state of the patients were assessed using the Cornell Scale for Depression in Dementia (CSDD) and the Functional Activities Questionnaire (FAQ). Principal component analysis and varimax rotation were used to determine the factor structure of the CMAI-T. Results: Factor analysis of the CMAI-T indicated a 3-factor structure: physically aggressive agitation, verbal agitation, and physically non-aggressive agitation. In 92% of the patients there >= 1 was agitation behavior during the previous 2 weeks. The CMAI-T total and factor scores were negatively correlated with the SMMSE scores, and positively correlated with the CSDD and the FAQ scores. Conclusions: The CMAI-T yielded 3 factors (physically aggressive agitation, verbal agitation, and physically non-aggressive agitation), which indicated the scale had construct validity Agitation behaviors were associated with cognitive dysfunction, symptoms of depression and general level of functioning. Additional research is necessary to identify the predictors of these dimensions in different dementia samples, and to determine the efficacy of therapeutic interventions.Article Citation - WoS: 3Citation - Scopus: 3Empirical and Statistical Modeling of Heat Loss From Surface of a Cement Rotary Kiln System(Gazi Univ, Fac Engineering Architecture, 2013) Simsek, Baris; Altunok, Taner; Simsek, Emir H.; Altunok, Taner; Makine MühendisliğiIn branches of industry too much energy consuming such as cement sector, controlled use of energy, only it is possible to know how energy is distributed in the system. In cement production process, a large portion of the heat losses which is due to energy consumption consist of convection and radiation heat losses from the surface of rotary kiln. In this study, empirical equation was derived for heat loss from surface of rotary kiln in a cement factory using empirical equations and statistical modeling techniques by the help of temperatures measured surface of rotary kiln. Measured with thermal cameras and the data necessary for experimental modeling was obtained the factory central control room. Total heat loss of system was calculated using Matlab. Statistical analysis related to results was carried out by Minitab 15.1.1 program. It was concluded that heat losses throughout rotary kiln increased toward the center of the kiln.
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