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In essence, a qualitative study revealing what the inhabitants reflect as a deep and personal relationship with and within the region, which contributes significantly to their sense of emotional security and self identity. This includes a strong conservation-orientated attitude with regard to the natural rural character of a clan, tribe or unbounded region using linguistic families, especially in the inner core. It acknowledges the journey though time of the dwellers, changes in requirements in a natural way. The principle behind this thesis is to identify the regional, cultural and environmental demands of where and how a fractal spatial function can be observed as well as how a community can be organised to maintain and preserve its culture in a natural way. Thus, responding to specific characteristics of the local environment and climatic conditions. This lifelong interaction between the cognitive and physical realms has existed overtime. During the evolution of values inhabitants adapted form and materials to the conditions of nature working with natural forms and climatic cycles rather than considering forces as obstacles to overcome has hermeneutic and practical values used by intentional makers. The cultural identity in the inhabitant made the home, and then the process of home-making ‘made’ the inhabitant a reciprocal reward. This will include their connection to the culture, region and environment while proposing a self-organizational solution. The future of conserving African tangible and intangible values, need to take lessons from the past into the future through present resolutions while documenting what maybe an interrupted progression. To achieve the above, I modified an approach using cultural fractal organizational approach as a basis for defining 1) The structure of research framework using computer simulations and thus establishing linkages between space, region and communal activities. 2) Using African linguistic families (Niger-Congo: Yoruba), as a distinct way of documenting within the context of co-existing social and discursive practices. 3) By generating a background in ethnographic and sensory archaeological data on Yoruba regional cities, focusing on the fractal structure of settlements in relation to the social activities that take place in and around them.

Bu tez marka topluluklarındaki bireylerin özbenzeşim ve aidiyet konusunda olası tutumlarını anlamak ve topluluk üyelerinin nostalji eğilimlerini, nostaljik tüketimlerini ‘imaj tüketimi’ kavramı üzerinden açıklamak amacıyla yazılmıştır. Tezin temel sorusu, Türkiye’deki marka topluluklarında nostaljik tüketimin, nostaljik imaj üzerinden yapılıp yapılmadığı ve bunun bir kendini ifade etme biçimi olup olmadığıdır.Tezin ilk bölümünde nostalji kavramının teorik arkaplanı incelenmiş ve imaj tüketimi kavramıya ilişkisi ortaya konulmuştur. Tezin ikinci bölümünde ise marka topluluk olma, kolektif benlik kavramları üzerinden marka toplulukları ve marka topluluklarında nostaljik tüketiminin imaj tüketimi kavramıyla ilişkisi açıklanmıştır.Tezin araştırması üçüncü bölümde yer almaktadır ve iki aşamalı olarak tasarlanmıştır. Araştırmanın birinci aşamasında Türkiye’deki Volkswagen Beetle toplulukları üyelerinden 8 kişiyle nitel araştırma yöntemlerinden odak grup görüşmesi yapılmış ve açıklayıcı repertuarlar üzerinden yorumlanmıştır. Araştırmanın ikinci aşamasında ise odak grup görüşmesinden alınan cevapları sorgulamak amacıyla yine aynı topluluğun üyelerinden 410 kişiyle nicel araştırma yöntemlerinden çevrimiçi anket çalışması yapılmıştır. Araştırma sonucunda Türkiye’deki Volkswagen Beetle topluluklarında nostalji eğiliminin ve nostaljik tüketimin yüksek olduğu bulgulanmıştır. Topluluk üyelerinin, kolektif özbenlik üzerinden geliştirdikleri topluluk aidiyetinin ve özbenzeşimlerinin yüksek olduğu sonucuna ulaşılmıştır. Teorik arkaplan ve yapılan iki aşamalı araştırma sonucunda topluluk üyelerinin, nostaljik tüketimi kişisel nostaljilerinden ziyade meta tüketimi üzerinden kendilerini ifade etmek amacıyla gerçekleştirdikleri ortaya çıkmıştır. Bu bağlamda kendilerini imaj tüketimiyle bir marka üzerinden ifade ettikleri sonucuna ulaşılmıştır.--------------------This thesis is prepared to understand the potential attitudes of the individuals in brand communities towards identification and belonging and to clarify the nostalgia proneness and nostalgic consumption of the community members through “image consumption”. The main question of the thesis is whether the nostalgic consumption in brand communities in Turkey are realized through nostalgic image and whether this is a self-expression method. In the first section of the thesis, the background of the nostalgia concept is investigated and its relationship with the notion of image consumption is presented. In the second section, the association of nostalgic consumption with image consumption in brand communities is clarified through notions of being a brand community and collective self.The thesis research can be found in the third section and is designed to contain two phases. For the first phase of the research; among the qualitative research methods, a focus group discussion is realized with 8 people from the Volkswagen Beetle communities in Turkey and this is interpreted through explanatory repertory. In the second phase, in order to support the answers gathered from the focus group discussion; a quantitative research method, an online survey research is conducted with 410 people from the same community. The research concluded that nostalgia proneness and nostalgic consumption is high in the Beetle communities in Turkey. It was concluded that the community belonging and identification that the brand members have developed through collective self is high. As an effect of theoretical background and two-phase research, it was realized that the community members carry out nostalgic consumption through meta consumption, rather than personal nostalgia, in order to express themselves. In this sense, it was concluded that they express themselves through a brand, with the process of image consumption.

Impinging jets have been widely used in the industry for cooling, heating, drying and many other purposes due to their excellent level of mass and heat transfer capacities. When issued into a confinement gap fully filled with working liquid, which is a typical configuration for the compact cooling devices designed to handle the extremely high heat fluxes generated by continuously working electronic components, they are classified as submerged confined impingement jets. Though the complicated flow field induced by the jet has attracted enormous amount of research efforts from heat transfer as well as fluid dynamics points of view, many key questions still remain unanswered. The present work reports a detailed experimental study of the flow field surrounding an axisymmetric, confined, impingement jet using stereo particle image velocimetry (SPIV). The experiments are conducted at three different orifice-to-plate spacings (2, 4 and 8 jet diameters) across Reynolds number ranging from 1000 to 9000. A maximum spatial resolution of 25 μm is achieved and the temporal resolution of the measurement remains 750 Hz. Special attention has been paid to the development of the triple-layered wall-jet with incomplete self-similarity. The jet core length and expansion angle for the vertical impingement jet has been calculated and presented. At small confinement height, the recirculating vortical structure has been found to strongly affect the wall-jet development. These flow field measurements and analysis will serve to inform a variety of practical applications in which impinging jets are used.

International audience; We propose top-down and bottom-up interval propagation techniques for identifying low leakage input vectors at primary inputs of an RTL datapath. Empirically, we observed self-similarity in the leakage distribution of adder/multiplier modules i.e., leakage distribution at the sub-space level is similar to that at the entire input space. We exploit this property to quickly search low leakage vectors. The proposed module library leakage characterization is scalable and is demonstrated on adders/multipliers. Given an RTL datapath, interval propagation is carried out with the low leakage intervals of the module instances with primary inputs. The reduced interval set is further processed with simulated annealing, to arrive at the best low leakage vector set at the primary inputs. Experimental results for various DSP filters simulated in 16 nm CMOS technology with top-down and bottom-up approaches yield leakage savings of 93.6 % and 89.2 % respectively with no area, timing, or control overheads.

航空宇宙技術研究所 16-18 Jun. 1999 東京 日本, National Aerospace Laboratory 16-18 Jun. 1999 Tokyo Japan, 計算機の急速な進歩とシミュレーション技術の不断の進歩により、CFD(数値流体力学)は製品設計、流れの予測の現場で広く普及している。一方、現在の工学CFDが抱える最も重要な課題は実用的な乱流モデルの開発であるが、この点ではまだ現在提案されている乱流モデルは複雑すぎ、実際にそれを用いることが難しい。乱流モデルを用いた計算には、その手法の根幹に関わる欠陥がないわけではないが、将来的には乱流モデルを用いた計算が工学CFDの現場で主流を占める可能性は大きいであろう。「乱流モデル応用研究会」は、実際に工学CFDにたずさわる若手研究者からなり、(1)各種実用問題に対する乱流の数値計算精度向上のための系統立った手法の確立と実行、および(2)既存乱流モデルの新しい利用法を確立すること、を目的として掲げている。乱流モデル自体の構築は研究会の主眼ではなく、モデルの純粋な利用者が無理なく参加できるようになっている。現在のメンバは24人で、メンバの数は徐々に増え続けている。会合は2ヶ月に1度で、幹事が中心となって設定した流れを研究会のメンバは各自のコードと乱流モデルを用いて計算し、結果を検討する。研究会のホームページでも結果を公開している。研究会の課題として、Karlssonら(1993)による2次元壁面噴流の実験を取り上げた。本稿では、低レイノルズ数型k-εモデル(Myong-Kasagiモデル)を用いて計算した計算結果の一例を報告した。平均速度や自己保存性などについて実験結果と計算結果を比較した。, By rapid progress in computer and steady development of simulation techniques, CFD (Computational Fluid Dynamics) is widely and practically used for product designs and flow predictions. Although one of the most important subjects in present engineering CFD is development of practical turbulence models, turbulence models having been proposed are too complicated for actual applications. Though computations using turbulence models have some problems, there is a possibility that computations using turbulence models are in the main stream of engineering CFD fields in future. The research group for the application of turbulence models consists of young researchers who actually work in the field of engineering CFD. The aims of the group are: (1) establishment and conduction of a systematic method which improves computation accuracy of the turbulent flows in various application problems; and (2) establishment of new applications of the existing turbulence models. The principal aim of the group is not for the construction of a turbulence model, so pure users of models can take part in the group without difficulty. Now there are 24 members in the group, and the members are increasing. A seminar is held once every two months, and the members compute a flow problem given by the host using their own code and model, and have discussions. The results are published on the Web site of the group. As a subject of the group, the two-dimensional wall jet experiment by Karlsson et al. (1993) is given. In this report, one example of the calculated results using low Reynolds number k-epsilon model (Myong-Kasagi model) is presented. The computation results are compared to the result of experiment on the average velocity, self-similarity, and so on., 資料番号: AA0001961044, レポート番号: NAL SP-44

Проаналізовано процес модифікації структури поверхнi гiбридного покриття TiN/Al2O3 пiд впливом низькоенергетичного сильнострумового електронного пучка. Шорсткiсть поверхнi розглянуто як функцiю струму пучка. Поверхнi отриманих зразкiв дослiджувались за допомогою двовимiрного мультифрактального флуктуацiйного аналiзу. Для кiлькiсного аналiзу змiни шорсткостi розрахована функцiя мультифрактального спектру. Показано, що зi збiльшенням енергії пучка поверхня стає бiльш регулярною та рiвномiрною. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/33940 A modification of the surface structure of the hybrid coating TiN/Al2O3 with a low energy high current electron beam (NCEB) is performed. The surface roughness is considered as a function of beam current. Surfaces of the obtained samples are investigated within the two dimensional multifractal detrended fluctuation analysis(MFDFA). The multifractal spectrum of the surface is calculated as a quantitative parameter of the roughness. It is shown that with an increase of the beam energy, the surface becomes more regular and uniform. При цитировании документа, используйте ссылку http://essuir.sumdu.edu.ua/handle/123456789/33940

Yonga üzeri ağlar, yonga üzeri sistemlerin ölçeklenebilirliğini ve performansını artıran yeni ve gelişen bir yonga üzeri haberleşme yöntemidir. Tasarım aşamasında karşılaşılan uygulama eşleştirme problemi genellikle toplam haberleşme enerjisi azaltma problemi olarak çözülür. Bu çalışma, problemi ağ tasarımı açısından ele alır ve toplam haberleşme enerjisini azaltırken arabelleklerdeki paket sayısı gibi ağ parametrelerini iyileştiren eşleştirme çözümleri bulmaya çalışır. Bunun için bir yonga üzeri trafik modeli gereklidir. Öz benzerlik, Ethernet trafiklerini olduğu gibi yonga üzeri haberleşmeyi de karakterize edebilen bir modeldir. Bu tezde yonga üzeri ağlar için bir öz benzer trafik modeli oluşturularak, hem enerji hem de arabellek kullanımı ölçütlerini içeren bir uygulama eşleştirme problem tanımı önerilmiş ve bu problemi çözmek için genetik algoritma temelli bir model geliştirilmiştir. Yapılan deneyler sonucunda bu problem tanımının haberleşme enerjisini düşük tutarken yüksek arabellek kullanımını önlediği görülmüştür. Network-on-Chip (NoC) is a developing and promising on-chip communication paradigm that improves scalability and performance of System-on-Chips. NoC design flow contains many problems from different areas, for example networking, embedded design and computer architecture. Application mapping is one of these problems, which is generally considered as a communication energy minimization problem. This dissertation approaches to this problem from a networking point of view and tries to find a mapping solution which improves the network performance in terms of the number of packets in the buffers while still minimizing the total communication energy consumption. For this purpose an on-chip network traffic model is required. Self similarity is a traffic model that is used to characterize Ethernet and/or wide area network traffic, as well as most of on-chip network traffic. In this thesis, by using an on-chip traffic characterization that contains self similarity, an application mapping problem definition that contains both energy and buffer utilization concerns is proposed. In order to solve this intractable problem a genetic algorithm based model is implemented. Execution of the algorithm on different test cases has proved that such a mapping formulation avoids high buffer utilizations while still keeping the communication energy low. 97

We construct a process with inverse gamma increments and an asymptotically self-similar limit. This construction supports the use of long-range-dependent t subordinator models for actual financial data as advocated in Heyde and Leonenko (2005), in that it allows for noninteger-valued model parameters, as is found empirically in model estimation from data.

7th International Wireless Communications and Mobile Computing Conference, IWCMC 2011 -- 4 July 2011 through 8 July 2011 -- Istanbul -- 86373 Metropolitan ring networks are usually used to connect the high speed backbone networks with access networks. Until now, the metropolitan network and the access network are gained much attention of researchers. However they have been investigated in separate ways. There is no work in which the end-to-end performance from end-users of the access network to metropolitan network is evaluated. How to simulate a complete end-to-end network while keeping basic characteristics of access and metro traffic is an emergence problem to evaluate the end-to-end performance. In reality, a complete end-to-end network in which hundreds of Ethernet Passive Optical Network (EPON) are connected to metro ring networks cannot be simulated because of the huge amount of traffic generated from the access network side. In this paper, we aim to obtain trace files of incoming traffic at the entrance of Optical Line Terminal (OLT) by running simulations of an EPON network which implements Interleaved Polling with Adaptive Cycle Time (IPACT). Then, the generated traffic pattern will be characterized in order to find corresponding traffic model among well known traffic models and this model will be used as output traffic of OLTs. After, we can use this traffic model without simulating a complete EPON network. Through various simulations, we observe that the generated traffic that comes to OLT is similar to the traffic obtained with Poisson sources © 2011 IEEE.

We present a parametric space study of the decay of turbulence in rotating flows combining direct numerical simulations, large eddy simulations, and phenomenological theory. Several cases are considered: (1) the effect of varying the characteristic scale of the initial conditions when compared with the size of the box, to mimic "bounded" and "unbounded" flows; (2) the effect of helicity (correlation between the velocity and vorticity); (3) the effect of Rossby and Reynolds numbers; and (4) the effect of anisotropy in the initial conditions. Initial conditions include the Taylor-Green vortex, the Arn'old-Beltrami-Childress flow, and random flows with large-scale energy spectrum proportional to $k^4$. The decay laws obtained in the simulations for the energy, helicity, and enstrophy in each case can be explained with phenomenological arguments that separate the decay of two-dimensional from three-dimensional modes, and that take into account the role of helicity and rotation in slowing down the energy decay. The time evolution of the energy spectrum and development of anisotropies in the simulations are also discussed. Finally, the effect of rotation and helicity in the skewness and kurtosis of the flow is considered., Sections reordered to address comments by referees

This paper reviews and extends some recent results on the multivariate fractional Brownian motion (mfBm) and its increment process. A characterization of the mfBm through its covariance function is obtained. Similarly, the correlation and spectral analyses of the increments are investigated. On the other hand we show that (almost) all mfBm's may be reached as the limit of partial sums of (super)linear processes. Finally, an algorithm to perfectly simulate the mfBm is presented and illustrated by some simulations., D\'epartement Images et Signal

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009, Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009, Bu çalışmada, tarihten günümüze mimarlık kavramı geniş bir perspektifte incelenmiş, her dönem farklı tasarım kriterleriyle mimari öğelerin üretildiği gözlemlenmiştir. Yapı tasarımlarına bakıldığında Öklid geometri ve Öklid geometri şekillerinin etkin olarak kullanıldığı tasarımlar biçimsel olarak değerlendirilmiştir. Diğer yandan bazı mimari akımların doğa tabanlı olduğu açıkça görülmektedir ve birçok doğa tabanlı mimaride de fraktallerin etkin rol oynadığı belirtilmiştir. Geçmişte de fraktallerin mimaride, doğadaki modellerin kopyalanmasından daha ileri boyutta kullanıldığı verisi elde edilmiştir. Günümüz mimarisinde kullanılan farklı yaklaşımlar irdelenerek, geometrik kurgular ile mimari biçimlenme arasındaki ilişki incelenmiştir. Bu ilişkiye biyolojik tabanlı önermeler getirilerek, bir yaşam formunda simbiyoz oluşturan elemanların fraktal kurgusunda var olan ilkeler kullanılarak mimari tasarımda bir yaklaşım önerilmiştir. Bu öneri ile yüzyıllarca doğada yaşamını sürdüren bir organizmanın –likenlerin- fraktal boyutuna dayanarak üretken bir tasarım ile yeni formların üretilmesi amaçlanmıştır. Tez kapsamında önerilen üretken mimari yaklaşım uygulanmıştır. Doğa tabanlı ve fraktal kurguya dayalı olarak ortaya çıkan tasarımın değerlendirilmesi yapılmıştır. Mevcut olduğu dokudan bağımsız olarak tasarlanan projenin, fraktal hesaplar sonucu oluşan yeni dokusuyla eskisi karşılaştırılmıştır. Bir bitki ve hayvanın birbirlerini besledikleri ve birinin diğerini görünür kıldığı - simbiyotik bir alan - ortak yaşamdaki kaosu fraktal geometriyle çözmek; biyolojiyi matematiksel bilime oturtmak ve bunu mimarlığa uyarlamak mimari tasarım bağlamında tartışılmıştır. Tezde elde edilen bulguların günümüz mimarlığına sağlayacağı katkılar ve uygulanabilirliği değerlendirilmiştir., The concept of “architecture“ is analyzed in the wide perspective since its early times, it is observed that in every time period within the distinct criteria architectural components have been produced. In the case of structural design; the shapes of the Euclid Geometry – bricks, steels, profiles, plates – are presented in manufacturing and marketing with easy solutions. Besides, the designs in which Euclid Geometry is used effectively are no surprise to encounter. On the other hand, it is clearly seen that some architectural trends are based on the nature and it is supposed that in some of this type of architecture, fractals are playing the key role. At this point, it is not hard to reach the further: Instead of copying the existing models in the nature, the real fractal architecture. In this study, while the approaches which are used in today’s architecture are examined, the relation between geometrical fictions and architectural formations are also observed. In this context of relation, a biology based architectural design is presented and in the same direction an approach is proposed by using the principles which are already existed in the fractal fiction elements. With this proposition, based on the fractal dimension of the organism that maintains its life for the centuries, new formations are the first targets to be reached in this generative approach. In consequence, the same approach is applied. The results of the constituted design based on the nature and fractal rules are evaluated in this part. Apart from the existing texture, the new texture obtained with different calculations is compared the old texture. An alga and a fungus are feeding each other and one of them makes other one visible – a symbiotic area – solving the chaos in common life via fractal geometry, predicating biology to mathematical basis and adapted this to the architecture are argued in the architectural design context. The contributions and applicability of the symptoms achieved from this thesis are evaluated., Yüksek Lisans, M.Sc.

�� �������������� �������������� �������������������� ���� ���������������� ���� ������������ ������������������ ���������������������� (long range correlations) ���� ���������������� �������� �������������� DNA. �� �������������� DNA ������������������������ �������� �������������������� ���������������������� ���������������� ��-����������. ������������ �������������������������� ���� �������������� ���� ������ ����������������������, ���� ���������� ������������ �� ������ ������ ������������������ �������������������� ��, ���� ������������ ������������������ ���� �������������������� ��������������������, �������� ������������������������ ������������ �� ������������������ ���������������������� �� ���������� �������������� ������ �������������������� ������ �������� ���������������� L ���� �������� k ��������������, ���������� ������ �� ���������������� ������ �������������� ������ �������������� ������ ������ ���������������������� ������ ���� ������������ ������������������ ���������������������� ������������������������ �������� �� ���������������� ������ ���������������������� ������������������������ ���� ������������������ ������ ������������ L. ������ ���������������� �������������������������� ���� ���������������������� ������������������ ������ ���� ������ ��������������������, ���������� ������ �� �������������������� �������� ���������� ���� ���������������������������� ��������������. �������������������������� �� �������������������� ������ ���������������������� ���������������� ������ ������ ������������������ (two-sided) ���������������� ������ ������������������������ �� ������������ ������ �������������������� (isotropy) ������ ���������������������� ������ ������������������������������ ���������������������� ����������������. ������ ������������������ ���������������� ������������������ �� ������������ ���������������������� ������������ ������������������ �������� �������������������� �������������� DNA ������ ���������� Arabidopsis Thaliana ������ �������������� �������������������� �������������� ������ ������������ ��. ����������, �������������� �������������������� ������ ���������������� ������ ���� ������ �������� �������������� �������� ���� ������������ ������ �������������� ������ ������ �� �������������� ��������., This work is referred to chains with long range correlations for application in DNA texts. The DNA chain is described through binary N-step Markov chains. At first the model is presented with two parameters, the memory length N and the correlation parameter �� which compose the conditional probability, with Moreover, the probability function of the words of definite length L and k unities, and the respective variance are obtained for and . When variance doesn���t exhibit linear dependence on L, long range correlations exist. Then, probabilities and are defined for and respectively and the probability of a word���s appearance in a permutative Markov chain. The equivalence of Markov���s symbolic sequences with the two-sided chains is proved and the isotropy of Markov and permutative Markov chains is established. In last section, the existence of long range correlations in Arabidopsis Thaliana is studied and we try to evaluate the memory length N. Finally, we investigate the statement that the probability depends only on the number k of unities, for

ジュリア集合の概念は今から60年以上前に数学者によって述べられていたがその当時は表現する手段が乏しかった。ジュリア集合に内在するフラクタル構造を，視覚的にとらえることができるようになったのは正にコンピュータの賜物である。フラクタル構造を特徴ずけるものに自己相似性がある。それは全体の構図がいくつかの全体の縮小した像で作られているものであり，その一つの例をジュリア集合に見ることができる。そこで，そのジュリア集合を求め種々の表現を用いて可視化することを試みる。, Concept of Julia set was drafted before one helf century. Meanwhile, The advent in recent years of inexpensive computer power and graphics are widely used in the solution of the problems of science.Fractal geometry, a concept introduced by B.B. Mandelbrot is a modern new language in the scientific world. Julia set is one of the fractal form with self similarity and I made several presentation (bird's eye view, colour) with visualization on computer.

International audience; Conformance testing for ad hoc routing protocols is crucial to the reliability of Wireless Mobile Ad Hoc Networks. Most of the works related to the validation of such protocols are based on simulation and emulation analysis of simulated/emulated implementations without taking into account formal specifications. However, for many reasons, it has often been shown that the results obtained from simulator studies are far from the real case studies. In this paper, we propose a new conformance testing methodology dedicated to the validation of MANET routing protocols, especially Dynamic Source Routing. After generating test sequences from the formal model, the main issue is to execute them. There exist many techniques in wired systems, but several MANET inherent constraints lead to cope with the diverse mobility patterns and the topological changes. Therefore, a nodes’ self similarity approach is introduced as well a specific testing architecture dealing with unexpected and unpredictable topology and messages. Interesting results have been provided as illustrated through experiments

�� ������������������ ������������������������ �������������� ���������������� ������ ���������������� ������ ������������������ ������ ������������������ ������ ������ ���������������� ���������� ������ ��������������������. ��' ���������� ������ �������������������� ���������������������� �������� ������������������ �������������������� ������������������������ ������ ������������������ �������� ���������������� ������ ������������ Hurst. �� �������������������� �������������� ���� ������������ ���������������� ������ ������ ������������ �������������� ���� ���������� �������������� ���� �������������� ������ �������� ���� �������������������������� ���� ������ ���������������� �������� �������������������� ������������������������ �������������� �������������������� ������ ���� ������������ ������ ������������ Hurst., Network intrusion detection aims at distinguishing the attacks on the internet from normal use of the internet. In this correspondence we propose an intrusion detection algorithm based on the estimation of Hurst exponent. The algorith input data comes from the network traffic. This data is seperated into several segments and after being hashed by applying a hash function to the algorithm can use them in order to estimate the Hurst exponent.

The Mumford process X is a stochastic distribution modulo constant and cannot be defined as a stochastic distribution invariant in law by dilations. We present two expansions of X—using wavelet bases—in X = X 0 + X 1 which allow us to confine the divergence on the “small term” X 1 and which respect the invariance in law by dyadic dilations of the process.

In studying the scale invariance of an empirical time series a twofold problem arises: it is necessary to test the series for self-similarity and, once passed such a test, the goal becomes to estimate the parameter H0 of self-similarity. The estimation is therefore correct only if the sequence is truly self-similar but in general this is just assumed and not tested in advance. In this paper we suggest a solution for this problem. Given the process {X(t),t∈T}, we propose a new test based on the diameter δ of the space of the rescaled probability distribution functions of X(t). Two necessary conditions are deduced which contribute to discriminate self-similar processes and a closed formula is provided for the diameter of the fractional Brownian motion (fBm). Furthermore, by properly choosing the distance function, we reduce the measure of self-similarity to the Smirnov statistics when the one-dimensional distributions of X(t) are considered. This permits the application of the well-known two-sided test due to Kolmogorov and Smirnov in order to evaluate the statistical significance of the diameter δ, even in the case of strongly dependent sequences. As a consequence, our approach both tests the series for self-similarity and provides an estimate of the self-similarity parameter.

Halfway between the N body model and the usual hydrodynamic, one the Vlasov equation (supplemented by the Poisson‐Maxwell equations) describes different media going from nuclear matter to the expanding universe (via semiconductors, plasmas, and stellar dynamics problems and the introduction of a quantum counterpart, the so‐called Wigner equation). In the first part we discuss the conditions of validity and how the equation can be pushed at the particle level through the dressed test particle picture. In a second part we discuss how, via water bag and multi water bag models, at least for one‐dimensional problems, the Vlasov model can be interpreted as a multifluid hydrodynamics and how mathematical similarities between 2D incompressible and the 2D phase space fluid can be used in vortex stability problems. The next part presents self similar group techniques and their embedding in the rescaling method to obtain the asymptotic solutions of expanding one species plasma and self‐gravitating universe. The last part shows how numerical methods must concentrate on keeping useful information and the interest of using as new numerical variables the dynamical invariants (energy, angular momentum, magnetic moment, etc.). This need to include analytical results into our numerical schemes for a better understanding of the Vlasov model will be our conclusion.

ÖZET ÇOĞULORTAM VERİ İLETİŞİMİNDE ÖZBENZEŞ DAĞILIM KULLANILAN TRAFİK MODELLEMESİ Analitik olarak basit ifade edilebildiklerinden dolayı ağ ortamındaki paket ulaşımları genellikle Poisson süreçlere uygun olarak modellenirler ve paket ulaşımlarının üssel dağılıma uyduğu varsayılır. Fakat son yıllarda yapılan araştırmalar göstermiştir ki, yerel alan ağlarında ve geniş alan ağlarındaki paket ulaşımlarının dağılımları üssel değildir. Bu çalışmalar ve araştırmalardan sonra, modern iletişim ağlarında özbenzeş süreçlerin Poisson süreçlerden daha iyi modeller sunduğu kabul edilmeye başlamıştır. Bu tezde, ilk olarak özbenzeşlik ile ilgili genel tanımlar yapılmış ve ilgili matematiksel eşitlikler gösterilmiştir. Ayrıca fraktallar, kaos torisi ve uzun süreli bağımlılık gibi özbenzeşlik ile ilgili diğer kavramlar açıklanmıştır. Daha sonra da çeşitli ağ ortamlarında yapılan deneylerden elde edilen trafik izlemeleri ve bunların incelenmesinden çıkarılan sonuçlar anlatılacaktır. Daha sonra, özbenzeşliğin derecesini belirlemekte kullanılan Hurst parametresinin kestiriminde en sık olarak kullanılan R/S analizi, değişinti - zaman analizi, periodogram tabanlı analiz, Whittle kestirimi ve dalgacık tabanlı analiz gibi metodlar ve arkasından da özbenzeşliğin orijinleri anlatılacaktır. Tezin son kısmında, tezin pratik kısmım oluşturan, C++ ve Matlab dillerinde yazılmış olan 2 program bulunmaktadır. İlk program C++ dili ile yazılmış, Pareto dağılımlı ON - OFF periyotlara sahip olan kaynaklardan oluşacak ağ trafiğinin toplanması ile özbenzeş trafik üreten bir simülasyon programıdır. Matlab dilinde yazılmış olan ikinci program ise gerek ilk program tarafından üretilen özbenzeş trafiğin gerek ise gerçek bir ağ ortamından alman trafik izlemelerin VIHurst parametresini değişinti - zaman metodunu kullanarak tahmin eden ve elde bulunan trafik izlemelerinin özbenzeş olduğunu ispat etmektedir. VII SUMMARY TRAFFIC MODELLING IN MULTIMEDIA DATA COMMUNICATION BY USING SELF - SIMILAR DISTRIBUTION Network arrivals are often modeled as Poisson processes for analytic simplicty, and packet interarrivals are assumed to be exponentially distributed. A number of studies have shown, however, that for local - area and wide - area network traffic, the distribution of packet interarrivals clearly differs from exponential. After that studies, it is generally accepted that self- similar (ox fractal) processes may provide better models for teletraffic in modern telecommunication networks than Poisson processes. In this thesis, first, general definitions and mathematical expressions related with self - similarity are explained. In addition to that all concepts related with self - similarity like fractals, chaos theory and long range dependence are summarized. After that diverse traffic measurements in a wide variety of networking situations are shown and their results are stated. After that, several approaches like for instance fractional Gaussian noise, fractional ARIMA processes, using of shot - noise processes, using of renewal reward processes and their superposition and chaotic deterministic maps are explained modeling self- similar traffic and origins of self- similarity are explained. At the last part of the thesis, there are 2 programs written by used C++ and Matlab programming languages. First program is written by using C++ programmin language and produce self - similar traffic by aggregating network traffic due to sources that have pareto distributed ON -OFF periods. On the other hand, second program is written by used Matlab programming language and estimates Hurst parameter of traffic traces produced by the simulation program and get from a real network. By means of this program, it is proven that the traffic traces are self- similar. VIII 95

ÖZET Yüksek Lisans Tezi ÖZ-BENZEŞÎMLÎ TRAFİK ANALİZ YÖNTEMİ İLE YEREL ALAN AĞLARINDA PERFORMANS TAHMİNİ Taner TUNCER Fırat Üniversitesi Fen Bilimleri Enstitüsü Bilgisayar Mühendisliği 2003, Sayfa: 66 Ağ mühendislerinin amacı ağ tasarımı yapıldıktan sonra mümkün olduğu kadar sorunsuz bir ağ ortamını kullanıcılara sunmaktır. Bu amaç için kullanıcıların istekleri olan yeterli bant genişliği, hafıza gereksinimi ve minimum paket kayıpları kriterlerini garanti etmek zorundadırlar. Bu önemli kriterler 1990'ların başına kadar Markov zinciri ve Poisson dağılımı gibi geleneksel ağ trafik analizi yöntemleri ile yapılmaktaydı. Oysa paket anahtarlamalı ağlar, zamanla patlamalı değişim göstermektedir. Böyle zamanla değişen patlamalı ağların analizini geleneksel yöntemler kullanarak yapmak doğru sonuç vermemektedir. Bu tür ağların analizinde, 1990' ların başında öz-benzeşimli trafik analiz yöntemi önerilmiştir. Öz-benzeşimli trafik analiz yöntemi ile bant genişliği, hafıza gereksinimi ve paket kayıplarının tahmini geleneksel yöntemlere göre daha doğru tahmin edilmiştir. Bu tez çalışmasında Fırat Üniversitesi yerel alan ağı için paket trafiği ölçümleri elde edilmiştir. Toplam ağ trafiğinin öz-benzeşimli özellik gösterdiği hesaplanmıştır. Ölçümlerin yapıldığı her bir zaman dilimi için bant genişliği, hafıza gereksinimi ve paket kayıplarının tahmini yapılmıştır. Anahtar Kelimeler: Geleneksel ağ trafik modeli, öz-benzeşimli trafik, trafik patlaması, Hurst parametresi. VII ABSTRACT Master Thesis PERFORMANCE EVALUATION OF LOCAL AREA NETWORKS BY SELF - SIMILARITY TRAFFIC ANALYSIS Taner TUNCER Fırat University Graduate School of Natural and Applied Sciences Department of Computer Engineering 2003, Page: 66 Having designed a network, the objective of network engineers is to provide the users with a network free from problems. For this reason, they must make sure that they allow sufficient bandwidth, memory requirement and minimal packet loss in the network. Such criteria were performed with conventional network traffic analysis such as Markov chaining and Poission distribution until the beginning of 1990's. However, packed-switching networks burst in time. It may not usually be possible to obtain accurate results in the above mentioned networks by conventional methods. In the analysis of such networks, the self-similarity traffic analysis method was suggested at the beginning of 1990's. With this method, memory requirement and packet loss can be estimated more accurately, compared with conventional methods. In this study, the packet traffic measurement was performed for the LAN of Fırat University. It was calculated that the total network traffic exhibited self-similar properties. The estimation of band-width, memory requirement and packet losses were realized for each time interval. Keywords: Conventional network traffic model, self-similarity traffic, traffic burst, Hurst parameter. VIII 66

ÖZET DVB ÜZERİNDEN IP: ÖZBENZEŞLİGİN YÖNETİMİ Sayısal Video Yayını (D VB) çoklu ortam verilerinin kullanıcılara iletimini MPEG-2 Taşıma Katan (TS) aracılığıyla sağlar. Çokluortam verisi kodlama ve sıkıştırmaya bağlı olarak değişken bit hızlı (VBR) veri özelliği sergiler. Çokluortam verisi bununla birlikte, farklı zaman ölçeklerinde çoğuşma özelliği gösterir. Çoğuşma özelliğinden dolayı VBR video, ortalama bit hızmdan daha fazla bant genişliğine ihtiyaç duyar. TS'i sabit hızlı kılmak için TS içine dolgu bitleri yerleştirilir. Bu tezde, MPEG-2 TS'de boşa harcanan bant genişliğinin, dolgu bitleri yerine İP trafiğinin doldurulması yoluyla kullanılmasına yönelik bir dizge önerilmiştir. Dizge üzerindeki trafiğin istatiksel özellikleri incelenmiş ve özellikler (özbenzeşlik, uzun-süreli bağımlılık) detaylı olarak anlatılmıştır. Önerilen dizgenin değişik ağ konfigürasyonlan ( darboğaz bant genişliği, ara bellek büyüklüğü) ve farklı trafik karakteristikleri (özbenzeşlik, Hurst parametresi) için benzetimi NS ağ benzetim aracı kullanılarak yürütülmüştür. Benzetim sonuçlarının analizi sonrasında bant genişliğini uyarlamanın,hem başarımı hem de kuyruk gecikmesini, ara bellek sığasını uyarlamaya göre daha etkince iyileştirmesi sebebiyle yeğlenen ağ özkaynağı olduğu sonucuna varılmıştır. IV ABSTRACT IP OVER DVB: MANAGEMENT OF SELF-SIMILARITY Digital Video Broadcasting (DVB) defines the carriage of multimedia information to clients by means of MPEG-2 Transport Streams (TS). Multimedia information, due to coding and compression, is variable bit rate (VBR) in nature. Furthermore it displays burstiness on different time scales. Due to its bursty nature, VBR video requires more bandwidth than its mean bit rate. Stuffing bits are inserted into the TS to make TS constant bit-rate. In this thesis, we propose a system, which makes use of the wasted bandwidth, due to stuffing bits in MPEG-2 TS, by carrying best-effort IP traffic with the prioritized video traffic. We investigate the statistical properties of the traffic on the proposed network. We give a detailed description for the traffic characteristics, i.e., self-similarity and long-range dependence. We use the NS simulator to simulate the proposed system for different network resource configurations, i.e., bottleneck bandwidth, buffer size, and different traffic characteristics, i.e., self-similarity (Hurst parameter). Analyzing the results, we suggest a bandwidth-driven network resource allocation policy, assuming a fixed overall traffic demand, since it improves both throughput and queuing delay. 82

We characterize the coordinate functions of Hilbert's space-filling curve using a directed-graph iterated function system and use this to analyze their fractal properties. In particular, we show that both coordinate functions have graphs of Hausdorff dimension $\frac{3}{2}$ and level sets of dimension $\frac{1}{2}$.

A major application of rescaled adjusted range analysis (RS analysis) is the study of price fluctuations in financial markets. There, the value of the Hurst constant, H, in a time series may be interpreted as an indicator of the irregularity of the price of a commodity, currency or similar quantity. Interval estimation and hypothesis testing for H are central to comparative quantitative Analysis. In this paper we propose a new bootstrap, or Monte Carlo, approach to such problems. Traditional bootstrap methods in this context file based on fitting a process chosen from a wide but relatively conventional range of discrete time series models, including autoregressions, moving averages, autoregressive moving averages and many more. By way of contrast we suggest simulation using a single type of continuous-time process, with its fractal dimension. We provide theoretical justification for this method, and explore its numerical properties and statistical performance by application 1,0 real data on commodity prices and exchange rates.