Perception and experience of incivility by urban youth : a field survey in Ankara

Ankara : The Department of Interior Architecture and Environmental Design and the Institute of Economics and Social Sciences of Bilkent University, 2009.Thesis (Ph. D.) -- Bilkent University, 2009.Includes bibliographical references leaves 191-203.There is a growing interest in studying (in)civility within the contemporary urban context due to disordered image of the city. This study focuses on incivilities resulting from daily encounters with strangers and experiences of incivility in daily life within a Turkish city context. Groups of youth around and their attitudes in urban public spaces are discussed to be the main incivil events in the social realm that prompt anxiety and unease among adult users of those spaces. In this respect, the aim of the study is to inquire different perceptions of incivility thoroughly and the ways it is perceived and experienced within the context of urban public spaces by the Turkish urban youth. First of all, the overall understanding of incivility in the Turkish urban realm is investigated through the statements of the urban youth and adults living in different neighborhoods of Ankara. Secondly, in order to explore the context dependent embodiment and locatedness of incivility as well as the role of space and physical environment, a field survey is conducted within a street context where everyday incivilities are mostly encountered. In this survey, Sakarya is chosen as the survey site concerning its significance with the variety of services and leisure activities on offer for the urban youth. The main purpose of this research is to investigate perceived and experienced incivilities and their interconnection with young people’s patterns of street use, which are expected to indicate problems in relation to social and physical environments of the street. Information on these issues was obtained through semistructured interviews and observation. The results indicate that while describing and explaining incivility, Turkish urban youth focuses on the importance of ‘respecting the norms and rules of the adult order of the society’ and the role of education and the family. They are observed to have different meanings and experiences of incivility in the street context and mostly describe and explain them in relation to the social environment. A mutual interference is found between perception and experience of incivility and the patterns of street use and young people’s attribution of meaning to the street. Likewise, variations in time of the day and gender differences among the youth appear to be influential on perception and experience of incivility on the street. Furthermore, Turkish youth is observed to be responsive to politics and social issues as well as planning and design of the urban spaces.Muğan, GülizPh.D

Social discrimination against teenagers in the mall environment : a case study in Migros shopping mall

Cataloged from PDF version of article.This study focuses on the issue of social discrimination against teenagers in shopping malls. Young people, as often being perceived to be threats to the dominant forces of adult world, experience constraints of the adult values in different public spaces. Considering the teenagers’ use of leisure time and spaces, the shopping mall has been observed as an extensively used space by this group for various reasons. In this research, Migros Shopping Center is the survey site, since its physical and social structures are appropriate to analyze the perceived social discrimination against teenagers. The main purpose of this research is to obtain clues for the sources of perceived discrimination patterns against teenagers in the mall environment, which is expected to indicate physical and social aspects of the problem, concerning the mall space of Migros. Information on these issues was obtained through observation and in-depth interviews. The results indicate that, although there are some dislikes, problems, injustices and perceived discrimination patterns of the respondents, most of the teenagers in the mall do not perceive social discrimination that has a mall origin on the contrary to their foreign counterparts. However, teenagers’ presence in the mall can be argued as resulting from discriminating factors such as parental restrictions, financial dependence and limited financial resources.Muğan, GülizM.S

Frequency and time domain analysis of model order reduction techniques

Model derecesi düşürme teknikleri büyük boyutlu dinamik simülasyonlarda işlem zamanını azaltmak ve süper eleman yaratmak amacıyla kullanılmaktadır. Bu çalışmada, Sonlu Elemanlar Metodu (SEM) kullanılarak popüler model derecesi düşürme tekniklerinden “Component Mode Synthesis (CMS)”, “Quasi-Static Mode Synthesis (QSM)”, Doğrusal olmayan en küçük kareler metodu(DOEK) ve Alt uzay temelli “Subspace-Based” tanımlama (AUT) metotları frekans ve zaman uzayında yapısal bir problem üzerinde incelendi. DOEK metodu ile AUT metotlarının, CMS ve QSM metotlarından daha iyi sonuçlar verdiği, fakat model derecesi arttıkça DOEK metodunun yakınsamadığı ve AUT metodunun yüksek dereceden modeller uydurduğu görülmüştür. Çalışmanın ikinci bölümünde ayrık eşdeğerlik prensibine göre geliştirilen “Impulse Response Invariant (IRI)”, İleri Farklar ve Newmark zaman entegrasyon metotları model derecesi düşürme tekniği olarak kullanıldı.Anahtar Kelimeler: Sonlu elemanlar metodu, model derecesi düşürme teknikleri, sistem tanımlama metodları, yapısal analiz, ayrık eşdeğerlik.Model order reduction techniques are commonly employed for dynamic simulation of large models and creating superelements. "Component Mode Synthesis", "Quasi-Static Mode Synthesis", nonlinear least squares and "Subspace-Based" identification methods are studied in time and frequency domains by using Finite Element Methods. In literature, phase errors of model order reduction techniques are commonly ignored, whereas it is an indication of performance of these methods and plays an important role in response of dynamical systems. It is observed that in general nonlinear least squares and "Subspace-Based" identification methods have better performance than "Component Mode Synthesis" and "Quasi-Static Mode Synthesis" methods; however, as the size of problems increases, the nonlinear least squares method may have convergence problems and "Subspace-Based" identification method may yield estimated models having large orders. Time response of the methods, in which convergence satisfied in frequency ranges, can not be able to fit with that of the exact system. Therefore, IRI, forward difference and Newmark time integration methods are developed on the base of discrete equivalent principle and used as a model order reduction techniques. Those methods can give good results when the active degrees-of-freedom are selected as the degrees-of-freedom to which forces and/or moments are applied. Keywords: Finite element methods, model order reduction techniques, system identification methods, structural analysis, discrete equivalent

Integrated optimum design of structures and LQR control systems

Bu çalışmada, yapının ve kontrol sisteminin birleşik optimum tasarımı çalışılmıştır. Yapı sonlu elemanlar metodu kullanılarak modellenmiş ve kontrolcü “linear quadratik regulatör (LQR)” formülasyonu kullanılarak tasarlanmıştır. Yapı ve kontrolcü eşzamanlı ve ardışık olarak optimize edilmiştir. Yapıların ve LQR formülasyonları kullanılarak kontrolcülerin eş zamanlı optimizasyonunun, yapıların yapısal tekil değer şekillendirmesi ile optimize edildiği ve başarılı bir şekilde herhangi bir ilgili kontrol kuralının tasarlanabileceği bir eşdeğer ayrık optimizasyon problemine indirgenebileceği gösterilmiştir. Yapıların ve kontrolcülerin ayrık optimizasyonu özellikle çok serbestlik derecesine sahip yapılar için belirli üstünlüklere sahiptir. Yapıların ve kontrolcülerin eş zamanlı ve ardışık optimizasyonları bir kafes yapı ve kontrolcüsüne uygulanmıştır. Birleşik LQR tasarım problemi için ardışık optimizasyon yaklaşımının eş zamanlı optimizasyon yaklaşımından çok daha hızlı global minimumu verdiği sonucuna varılmıştır. Anahtar Kelimeler: Yapısal optimizasyon, optimum kontrol, tekil değer ayrıklaştırması, sonlu elemanlar metodu.  In this study, integrated optimum design of structures and control systems is studied. The structures are modeled by the use of finite elements method, and the controllers are designed by the use of linear quadratic regulator (LQR) formulation. The structures and controllers are optimized simultaneously and successively. It is shown that simultaneous optimization of structures and controllers by using LQR formulations can be achieved by an equivalent decoupled optimization problem where structures are optimized by shaping the structural singular values and succeedingly any control law of interest can be designed. Decoupled optimization of structures and controllers has certain advantages, especially for structures having large degrees-of-freedom (DOF). Computational cost of the associated singular value shaping problem is very low since it is only necessary to compute the largest and smallest singular values that can be computed by using selective eigenvalue solvers. Model order reduction techniques should be employed at every design iteration for simultaneous optimization approach in order to design LQR laws; however, successive optimization approach developed in this paper does not need any model order reduction technique during structural optimization and can easily be implemented into problems having large DOF. Then, simultaneous and successive optimization of structures and controllers are applied to a truss structure and its controller. it is concluded that successive optimization approach to integrated LQR design problem yields the global minimum much faster than the simultaneous optimization approach. Keywords: Structural optimization, optimum control, singular value decomposition, finite element method

Design sensitivity analyses of structures based on singular value decomposition

Bu çalışmada, lineer cebirin araçlarından olan Tekil Değerlere Ayrıştırma “TDA” (Singular Value Decomposition, SVD) metodu, yapısal sistemlerin tasarım duyarlılığı analizlerine uygulanarak TDA'ya dayalı duyarlılık analizi yöntemi geliştirilmiştir. Bir yapısal sistemin tekil değerlerinin şekillendirilmesi, aynı zamanda sistem cevabının belirlenmesi anlamına gelmektedir. Buradan hareketle, geliştirilen TDA'ya dayalı duyarlılık analizi yöntemi ile mevcut klasik tasarım duyarlılığı metodlarının statik, dinamik analizler, çoklu yükleme hali ve yapısal gürbüzlük gibi alanlarda karşılaştırmaları yapılmış ve yöntemin performansı sayısal örnekler üzerinde denenmiştir. Yöntemin belli alanlarda klasik metodlara göre daha fazla bilgi açığa çıkarmasının yanı sıra, hesaplamalı alanda işlemci süresi ve hafıza kullanımında büyük avantajlara sahip olduğu görülmektedir. Anahtar Kelimeler: Tasarım duyarlılık analizi, tekil değerler, tekil değerlere ayrıştırma, en kötü yükleme hali, yapısal gürbüzlük.In this study, the singular value decomposition (SVD) is employed for design sensitivity analyses of structures. As the squares of singular values are the bounds of power, energy and power spectral density ratios between the input and output vectors, shaping the singular values of a structure. is equivalent to shaping the response of the structure. Comparison is made of the proposed sensitivity analysis based upon the SVD with static and dynamic responses, and eigenvalue design sensitivity analyses. The issues such as structural robustness, worst loading case and multiple load cases are studied. As shown, design sensitivity analyses based upon the SVD can give good insight into static and dynamic response characteristics of structures. Several numerical examples are also presented to illustrate the proposed approach. As a result, the SVD based analysis is compared with the classical techniques yield more information and computationally advantageous particularly in case of multiple load cases, finding worst case loading and sensitivity bounds of a structure. Another advantage of this method is that it is well suited for finite element method equations which is the most popular method among computational methods especially in modeling continuous structures. That?s why the proposed method can be applied to sensitivity and optimization algorithms of well-known commercial analysis softwares such as Ansys, Nastran etc.Keywords: Design sensitivity analysis, singular values, singular value decomposition, worst case loading, structural robustness

Improvement of structural dynamic finite elements responses by using super elements and structuring

Bu çalışmada yapısal dinamik problemlerin analizlerinde sonlu elemanlar yöntemi ile elde edilen cevaplarının süper elemanlar ile iyileştirilmesi incelenmiştir. Geliştirilen yeni model derecesi düşürme (MDD) yaklaşımları ile olumlu sonuçlar elde edilmiştir. Bu yeni yaklaşımlar sistem zaman cevaplarının eşitliğini sağlayacak serbestlik derecelerinin aktif serbestlik dereceleri olarak MDD uygulanmış sistemin içine taşınması temeline dayanmaktadır. Hazırlanan Matlab kodları ile geliştirilen model derecesi düşürme yöntemi örnek yapılara uygulanmış ve alınan zaman cevabı sonuçları, orijinal modelin sonuçları ile karşılaştırılmıştır. Tüm bu karşılaştırmalarda Rayleigh sönüm modeline uygun farklı katılık orantılı sönüm matrisi durumları dikkate alınmış ve farklı model dereceleri için hesaplama zamanları açısından sonuçlar değerlendirilmiştir. Ayrıca farklı MDD teknikleri ile elde edilen sistem toplam enerji miktarı orijinal modelin toplam enerjisi ile karşılaştırılmıştır. Çalışmada alt yapılara bölme (AYB)-“Substructuring” yöntemi de incelenmiştir. Geliştirilen Matlab kodu ile plak sistemleri üzerinde AYB uygulamları yapılmış, sonuçlar orijinal model cevabı ile karşılaştırılmıştır. Oluşturulan süper elemanların kullanılması ile de hesaplama zamanları önemli ölçüde düşürülmüştür. Ancak süper eleman oluşturmaya harcanan zamanın yüksek olduğu ve AYB yönteminin geliştirilen MDD yönteminden daha kötü performans gösterdiği görülmüştür. Yapılan tüm karşılaştırmalar sonucunda çalışmada incelenen yöntemlerin çok düşük olan sönüm durumları dışında, orijinal model ile uyumlu zaman ve frekans cevapları verdiği, MDD uygulanmış sistemin orijinal model ile aynı enerji seviyelerinde bulunduğu ve karşılaştırılan diğer MDD yöntemlerinden çok daha az hesaplama zamanına ihtiyaç duyulduğu görülmüştür.  Anahtar Kelimeler: Sonlu elemanlar yöntemi, model derecesi düşürme, alt yapılara bölme, süper eleman.In this study, the responses obtained by the Finite Element Analyses of structural dynamic problems are studied. With the developed model order reduction approach, some improvements have been gained. The developed model order reduction method is essentially based on the equality of the total energies of both original and reduced systems and therefore it is named as “Equality of the total energies”. In the new approach, respecting the degrees of freedoms (DOF)s that give responses conforming with original system is assumed as the main criteria for selection of active DOFs. In this study, the main significant step is the selection of the active DOFs according to their influence to the system time response. The groups of active are application points of the external loadings and the DOFs having high stress or deflection values maximum because they are very important to reveal the right system response. For better accuracy, DOFs close to loading application points are also transferred into reduced system. Heuristic method had been also used for the selection of the active DOFs by some trials and errors to get better consistency between the original system response and reduced system response. Developed model order reduction method was applied to a sample 2D truss system and cantilever plate by some Matlab codes, and the results of the reduction analyses are compared with the original system responses in response to various loadings, eg. İmpulse, step and sinusoidal inputs. In the same Matlab codes, time responses of some other model order reduction methods –Forward differences, Newmark integration and impulse response invariant (IRI)- are also implemented to the same original model. Various Rayleigh damping models for the sample system are taken into account in all these comparisons and the results of analyses for different model orders are evaluated in terms of calculation time and accuracy. Frequency domain responses of the original and the reduced systems by different approaches are also compared with each other based on Bode diagrams by considering the stiffness proportional damping. In parallel, the total energy levels of the reduced systems are also compared with the original system energy level. While auditing of the system responses and Bode diagrams, it is noted that the compatibility of both the original and the reduced systems increases in parallel with the stiffness proportional damping value. In evaluation of the results, it could be expressed that the change in stiffness proportional damping value does not affect the calculation time. While comparing the total energies of original and reduced systems, it is observed that their consistency is good enough to state that both systems have the same system characteristic. Bode diagrams which reflect frequency response of a system, are assumed to be the main criteria to evaluate the performance of the reduced system for both high and low frequencies. It is concluded in general that when the number of an element type used in the analyses decreases, the amount of the DOFs which could be omitted from the original system increases and also the order of the reduced system decreases by keeping the same expected accuracy. As a result of observation, the limit of the model order reduction depends on the selected elemen type. Another conclusion is that general behavior of the damped or undamped systems do not affect the selected element numbers for the reduced system. In the study, substructing method is also taken into considerations. By using Matlab codes, substructuring is implemented into a plate system and the results are compared with the original system. It is observed that the calculation time is extremely reduced by using super elements Nevertheless, since the time for calculation of super elements is long, it is seen that substructuring exhibits worse performance than developed model order reduction method. After all comparisons, it is noted that the developed method gives compatible time and frequency responses with the original model except too low stiffness proportional dampings. It is also observed that the energy level of the reduced system obtained by this new model order reduction method is almost the same with the energy level of the original model. Finally, the most advantageous feature of equality of the total energies method was determined on the calculation time and it needs less calculation time than the other compared model order reduction methods during all examples carried out in the study. Keywords: Finite element method, model order reduction, substructuring, super element

New contiguity relation of the sixth Painlev\'e equation from a truncation

For the master Painlev\'e equation P6(u), we define a consistent method, adapted from the Weiss truncation for partial differential equations, which allows us to obtain the first degree birational transformation of Okamoto. Two new features are implemented to achieve this result. The first one is the homography between the derivative of the solution $u$ and a Riccati pseudopotential. The second one is an improvement of a conjecture by Fokas and Ablowitz on the structure of this birational transformation. We then build the contiguity relation of P6, which yields one new second order nonautonomous discrete equation.Comment: LaTex 2e. To appear, Physica

On the Schlesinger transformations of the sixth Painlev\'e equation

Following the recent discovery of two new Schlesinger transformations (ST) for the sixth Painlev\'e equation, we give the interrelations between all the known STs. We thus isolate the unique one which at the same time conserves the independent variable and is not a product of other STs.Comment: in French, LaTeX, 5 pages, to appear, Comptes rendus Acad. Sci. Pari

Growing tendency to harmonisation with IFRS: some evidences from Turkey

Motivated by the recent developments in accounting regulations, we explore the tendency of countries to converge to IFRS for both public and private companies and present some evidence on the issue from an emerging market. We explore how the legal system – civil vs. common law – and the stock market development stage in a country affects the acceptance of IFRS by the regulators. We find that stock market influences the acceptance of IFRS for both public and private companies while the legal system affects the requirement of IFRS for the private companies. In Turkey, different regulatory bodies control different types of companies. Capital Markets Board that controls the listed companies issued the first set of translated IFRS in 2003. Established in 2002, Turkish Accounting Standards Board (TASB) is responsible to translate and issue the international accounting standards. Examination of issue and effective dates of both standards reveals that TASB closely follows the IASB efforts. © 2009 Inderscience Enterprises Ltd

Metal hidrür bataryalar için CaNi₅-xMx esaslı bileşiklerin üretimi ve karakterizasyonu.

Ni - MH batteries have superior properties which are long cycle life, low maintenance, high power, light weight, good thermal performance and configurable design. Hydrogen storage alloys play a dominant role in power service life of a Ni - MH battery and determining the electrochemical properties of the battery. LaNi5, belonging to the CaCu5 crystal structure type, satisfy many of the properties. The most important property of LaNi5 is fast hydrogen kinetics. Recently, CaNi5, belonging to same crystal type, has taken some attention due to its low cost, higher hydrogen storage capacity, good kinetic properties. However, the main restriction of its use is its very low cycle life. The aim of the study is to obtain a more stable structure providing higher cycle life by the addition of different alloying elements. In this study, the effect of sixteen alloying elements (Mn, Sm, Sn, Al, Y, Cu, Si, Zn, Cr, Mg, Fe, Dy, V, Ti, Hf and Er) on cycle life was investigated. Sm, Y, Dy, Ti, Hf and Er were added for replacement of Ca and Mn, Sn, Al, Cu, Si, Zn, Cr, Mg, Fe and V were added for replacement of Ni. Alloys were produced by vacuum casting and heat treating followed by ball milling. The cells assembled, using the produced active materials as anode, which were cycled for charging and discharging. As a result, replacement of Ca with Hf, Ti, Dy and Er, and replacement of Ni with Si and Mn were observed to show better cycle durability rather than pure CaNi5.M.S. - Master of Scienc