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Strengthening of infilled rc frames with carbon fiber composites
Get PDFÇalışma kapsamında, birbirine bitişik, dolgu duvarlı çift taraflı sıva uygulamasının mümkün olmadığı betonarme yapılarda, tek yüz/çift yüz sıvanın etkisi ve çerçeveye olan katkısı, tek/çift taraflı karbon lifler ile güçlendirmenin yapıda nasıl bir performans göstereceği üzerinde çalışılmıştır. 6 adet, 1/3 ölçekli, tek açıklıklı, tek katlı numuneler üzerinde, bu tür sistemlerin yatay yük taşıma kapasiteleri, rijitlik ve enerji sönümleme gibi özelliklerini karşılaştırmak amacıyla deneysel ve analitik çalışmalar yapılmıştır. Numuneler; boş çerçeve, dolgu duvarlı / tek yüzü ve çift yüzü sıvalı çerçeve, dolgu duvarlı tek yüzü sıvalı tek yüzü/çift yüzü karbon lifli kompozitler ile güçlendirilmiş çerçeve olarak üretilmiş, her numune üzerinde yerdeğiştirme kontrollü yük artırımı yöntemi uygulanarak, numuneler deneye tabi tutulmuşlardır. Elde edilen sonuçlar kuramsal çözümlemeden elde edilen sonuçlar ile karşılaştırılmıştır. Deney sonuçlarına göre belirli işlem kriterlerine bağlı kalındığında söz konusu tek ve çift taraflı güçlendirme yönteminin her ikisinin de deney elemanlarının göçme davranışları, yatay yük taşıma gücü, enerji sönümleme miktarı ve rijitlik değerleri bakımından olumlu sonuçlar sağladığı ortaya konmuştur. Eşdeğer diyagonal basınç çubuğu kavramı kullanılarak dolgu duvarlar modellenmiş, analitik çalışma deneysel çalışmada elde edilen global davranışı yeterli bir yakınsaklıkla tahmin etmiştir. Anahtar Kelimeler: Karbon lifli kompozitler, dolgu duvarlı çerçeve, güçlendirme.The main contribution of this study is to analyze the effect of frames with single/double-sided plasters and its benefits on the frame in adjacent reinforced concrete structures with infilled walls where it is not possible to apply double-sided plasters as well as strengthening the walls with carbon fiber composites materials. Within the scope of work, 6 single-bay, one-story, 1/3 scaled reinforced concrete frames were designed which reflects the properties of reinforced concrete structures in practice and these specimens were tested to compare the lateral load capacity, rigidity and energy dissipation values of the specimens. Specimens were designed as bare frame, infilled frames with single/double side plastered and infilled frames of single side plastered, single side/double side strengthened with carbon fiber composites and tested under cyclic horizontal loads. Various researches have investigated the performance of reinforced concrete frames with infilled walls strengthened/unstrengthened with carbon fiber composites and applied single/double sided plastered and some principles were suggested for a successful application. The test results were compared with the numerical results obtained from the nonlinear static pushover analyses. For this purpose, the scope and purpose of the study, the concept of retrofitting, the effects of infilled walls to the behavior of rc frames and strengthening methods of infilled walls with carbon fiber composites were described in this study. It was highlighted that the strengthening method with carbon fiber composites would be used very frequently in the future. Also, the geometric properties of the specimens, the mechanical properties of materials used at producing the specimens and the procedure of the experimental study were explained. After the experimental results were described in detail, the analytical study was completed and the conclusions and recommendations based on the test results compared with the analytical studies. The test results proved that the both single and double sided strengthening method with carbon fiber composites applied on the infilled walls improved the lateral load capacity, rigidity and energy dissipation values of the specimens. The infilled walls were modeled by using equivalent diagonal strut concept and calibrated with the test results. The models generally predicted the global behavior of the specimens satisfactorily. The procedure of strengthening diagonally of the reinforced concrete frames with carbon fiber composites from one corner to other was suggested as a useful method and it was observed that the lateral load capacity of strengthened infilled frames is approximately two times bigger than the unstrengthened infilled frame with successful anchorage. More important, while the unstrengthened infilled frames shows bare frame behaviour after failure under cyclic horizontal loads, the strengthend frame dissipated more energy after failure of the specimen. CFRP anchors applied to the diagonal carbon fiber composites on the infilled walls provided to hold the CFRP on the infilled walls more efficiently. To increase the number of CFRP anchors from double sides on the infilled wall and at beam-column joints is recommended for efficient strengthening. Strengthened test specimens behaved more ductile and their maxiumum load carrying capacities were at higher values than unstrengthened specimens after failure of the specimen. Keywords: Carbon fiber, strengthening, infilled wall, equivalent strut, test
Studying on critical exponents around glass transition; A fast transient fluorescence study
Get PDFSerbest radikal çaprazbağ kopolimerizasyonu (FCC) ile elde edilen etilmetakrilat (EMA) kopolimerizasyonunda zaman ayrımlı floresans teknik kullanılarak camsı geçiş çalışılmıştır. Floresans molekül olarak Piren (Py) seçilmiştir. Floresans bozunum eğrilerinden piren molekülünün floresans yaşam zamanı hesaplanmış ve camsı geçişin izlenmesi için kullanılmıştır. Camsı yapı oluşumu ile reaksiyon ortamının yoğunluğundaki değişim piren moleküllerinin floresans verimini etkiler. Bu etki farklı sıcaklık ve çapraz bağlayıcı konsantrasyonlarında EMA’nın camsı geçişinin çalışılmasına olanak sağlamıştır. Camsı geçiş noktası civarında jel kesrine ve ortalama küme büyüklüğü ait kritik üsler b=0.36±0.002 ve g=1.68±0.01 hesaplamış ve sonuçlar sızma teorisi ile uyum içerisinde bulunmuştur. Anahtar Kelimeler: Camsı geçiş, kritik üsler, zaman ayrımlı floresans teknik.The bulk free radical crosslinking copolymerization is divided into three different stages; low conversion stage, gel effect stage, and glass effect stage. The glass effect stage occurs as the last stage of polymerization, if the reaction temperature is lower than the glass transition point of the polymer. The glass transition during polymerization was studied in free-radical crosslinking copolymerization (FCC) of ethyl methacrylate, (EMA) using the fast transient fluorescence (FTRF) techniques. Pyrene (Py) was used as a fluorescence probe. The fluorescence lifetimes of Py from its decay traces were measured and used to monitor the glass transition. Changes in the viscosity of the pregel solutions due to glassy formation dramatically enhance the fluorescent yield of Py molecules. The reaction time at which the Py lifetime exhibit sudden increase corresponds to the reaction time at which the rate of polymerization becomes maximum resulting from the gel effcet. This effect is used to study the glassy formation of EMA, as a function of time, at various crosslinker concentrations and different temperatures. The results were interpreted in the view of percolation theory. The gel fraction, b and weight average degree of polymerization, g exponents were measured near the glass transition point as b =0.36±0.002, g =1.687±0.01 and the results are found in agreement with percolation results. Keywords: Glass transition, critical exponents, time resolved fluorescence technique
Separation and determination of some metals in sodium trimetaphosphate media, with cation-exchange chromotography
Get PDFSülfolanmış bir polystiren reçine olan Dowex 50W-X8 (200-400 mesh) üzerinde, 0,01 ile 0,3 M arasında sodyum trimetafosfat konsantrasyonları kullanılarak bazı elementlerin dağılım katsayıları incelenmiştir. Dağılım katsayılarının değerlendirilmesiyle 0.1 M sodyum trimetafosfat kullanılarak elementlerin ayrılmaları sağlandı. Küçük miktardaki ayırmalar için her elementten 0.5’er mg, büyük miktardaki ayırmalar için her elementten 30’ar mg kullanıldı. Sonuçlardan anlaşılacağı gibi sodyum trimetafosfat, incelenen elementler için yeni bir elüent olarak kullanılabilir. Bu ayırmalar için sodyum trimetafosfat, diğer elüentlere göre bazı avantajlara sahiptir. Kuyruk etkisi çok küçük, ayırma zamanı diğer bilinen metotlardan daha kısadır. Elüsyon pikleri dar ve hemen hemen simetriktir. Kalitatif ve kantitatif incelemeler spektroflorometre ile yapılmıştır. Anahtar Kelimeler: Sodyum Trimetafosfat, metal iyonlarının ayrılması, iyon değişimi kromatografisi.In this study it was thought that sodium trimetaphosphate can be studied as an eluent for the separation of elements with ion exchange method. For this purpose the elements which are suitable were selected. Firstly the distribution coefficients of these elements (Ba, Cd, Co, Ga, K, Ni, Zn ve Pd) with Dowex 50W-X8, 200-400 mesh, a sulphonated polystyrene resin were determined by using different concentration ranges between 0.01-0.3 M of sodium trimetaphosphate. By concidering of these distribution coefficients separation were performed with 0.1 M sodium trimetaphosphate at room temperature. For quantitative and qualitative small scale separation, 0.5 mg of each element and for preparative large scale separation 30 mg of each was used. From the obtained results it has been seen that sodium trimetaphosphate can be used as a new elution agent for determination and preparative separation of mentioned metal ions. For the separation of these metals, sodium trimetaphosphate as elution agent has the following advantages over the other elution agents. The tailing effects are very small and the separation time much shorter than the other known methods. The elution peaks are narrow and nearly symmetrical. Qualitative and quantitative determination of ions were done by using spectrofluorimeter method. Keywords: Sodium trimetaphosphate, metal ions separations, cation-exchange chromatography
Direct determination of manganese in vitamin?mineral tablets using SS-GFAAS
Get PDFElektrotermal Atomik Absorpsiyon Spektrometrisi ile geleneksel olarak yapılan analizlerde, örneklerin çözülmesi, istenmeyen maddelerin uzaklaştırılması ve eğer gerekiyor ise seyreltme veya ön zenginleştirme işlemlerine gerek vardır. Örneklerin çözülmesi ve analize hazır hale getirilmesi genel olarak analizin en zahmetli ve zaman alıcı bölümüdür. Eser ve ultra eser element analizlerinde yukarıdaki işlemler nedeniyle analat kaybı veya örneğin kirlenme riski oldukça artmaktadır. Bu çalışmanın amacı çözme işlemi gerektirmeden çeşitli örmekler içerisindeki metal analizleri için katı örnekleyici grafi fırınlı atomik absorpsiyon spektrometrisi (GFAAS) ile yöntem geliştirmektir. Doğrudan katı örneklerden edilen değerler çözelti tekniği sonuçlarıyla karşılaştırıldığında katıların doğrudan analizi tekniğinin vitamin-mineral tabletlerdeki Mn analizleri için başarıyla uygulanmasının gerçekleştirildiği görülmektedir. Anahtar Kelimeler: Katı örnekleme, mangan, eser element analizi, ETAAS.Analysis of trace elements using electrothermal atomic absorption spectrometry requires dissolution of samples, removal of unwanted materials from sample solutions or some pre concentration processes. Dissolution of samples and preparation of samples to analysis are the most troublesome and time consuming steps of any analysis. In case of trace and ultra trace elements, the loss of analyte and risk of contamination of sample increases due to above processes. The only way of overcoming this problem is to analyze sample directly without any pre-treatment. It can be only possible by using solid sampling system. The aim of this study is to investigate new methods for determination of trace metals in different samples without dissolution by using solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS). Working conditions (effects of pyrolysis temperature, atomization temperature and sample mass on absorbance) of solid sampling systems were investigated. Using optimum working conditions, Mn concentration of vitamin-mineral tablets was determined by using different calibration techniques. After dissolving samples with acid mixtures Mn content of vitamin-mineral tablets found as 193 + 5 mgkg-1. Mn concentration of vitamin-mineral tablets was determined by using solid sampling ETAAS with different calibration techniques. When these values are compared with the result of conventional solution technique, the results obtained by different direct solid sampling calibration techniques were in agreement with that found by solution technique. Keywords: Solid sampling, manganese, trace element analysis, ETAAS
Quaternization of poly(4-vinyl pyridine) beads with 2-chloroacetamide for selective mercury extraction
Get PDFÇapraz bağlı poli(4-vinil pridin) reçinesi ‘Reillex 425’ 2-kloroasetamid ile hemen hemen kantitatif olarak DMF çözücüsü içinde kuaternize edildi. 4.03 mmolg-1 kuaternizasyon yoğunluğu ile kuaternize reçine, sulu çözeltiden seçimli civa ayrılması için etkin bir sorbenttir. Reçinenin 4 mmolg-1 civarındaki civa yükleme kapasitesi, civa bağlanmasının monoamido civa yapısı ile gerçekleştiğini göstermektedir. Yabancı iyonlar Ca(II), Mg(II), Zn(II), Cd(II), Pb(II) ve Fe(III) iyonları için 0.15 M konsantrasyonda reçine tarafından ihmal edilebilir miktarda (0.1 mmolg-1) absorpsiyon gözlenmiştir. Civa bağlanması yeterince hızlı gerçekleşmekte ve birinci mertebe kinetik göstermektedir (civa asetat çözeltisinde k=2.38 x10-3 s-1 ve civa klorur cozeltisinde k = 1.29x10-3 s-1). Kuaternize reçine sıcak asetik asit ile bağlanan civanın ayrılması ile rejenere edilebilmektedir. Anahtar Kelimeler: Poli(4-vinil pridin) reçine, kuaternizasyon, seçimli civa ekstraksiyonu.Crosslinked poly(4-vinyl pyridine) resin Reillex® 425 has been quaternized almost quantitatively with 2- chloroacetamide in DMF solvent. The quaternized resin with 4.03 mmolg-1 quaternization density is an efficient sorbent for selective mercury extraction from aqueous solutions. About 4 mmolg-1 mercury loading capacity of the resin implies that mercury sorption takes place mostly by formation of monoamido-mercury structures. To inspect selectivity of the quaternary resin, metal extraction experiments have been repeated with Ca(II), Mg(II), Zn(II),Cd(II), Pb(II) and Fe(III) ions at the same conditions. As it might be expected only neglible amounts of metal sorptions are observed in Zn(II), Cd(II), Pb(II) and Fe(III) ions. Extracted amounts lie in experimental error limits and accounts for less than 3.2% of the mercury sorption. Ca(II) and Mg(II) ions on the other hand do not show any absorbtivity by the sorbent. The quaternary sorbent is also efficient for low mercury concentrations and mercury sorption kinetics represent first order kinetics. Rate constants (from slopes of corresponding semi log plots) of the sorption from mercuric acetate and chloride solutions were found k=2.38x10-3 s-1 and 1.29x10-3 s-1. The quaternized resin can be regenerated by stripping of the sorbed mercury with hot acetic acid without hydrolysis of amide group. Keywords: Poly(4-vinyl pyridine) resin, quaternization, selective mercury extraction
Preparation and comparison of standard and mesoporous WO3 films
Get PDFBu çalışmada, standart ve gözenekli WO3 filmler, başlangıç malzemesi olarak tungsten hekzaklorit (WCl6) ve ethanol kullanılarak sol-gel yöntemlerinden olan döndürme tekniğiyle hazırlanmıştır. Gözenekli tungsten oksit filmler, tungsten oksit solune dört farklı tip polimer eklenerek kaplanmıştır. Söz konusu polimerler: (BASFTM Pluronic p123) (p1), poly(ethylene glycol) (p2), polyethylene glycol-ran-propylene glycol (p3) ve polystyrene-co-allyl-alchl (p4)’dır. Bu polimerler kullanılarak gözenekli WO3 filmler hazırlanmış ve filmlerin optik, yapısal ve elektrokromik özellikleri standart (s1) WO3 filmler ile kıyaslanmıştır. Filmlerden UV aydınlatma yöntemi ile polimer kalıpların uzaklaştırılması başarılmıştır. Aynı zamanda UV aydınlatma işlemi uygulanmış tungsten oksit filmlerin renklenme etkinliği değerlerinde düzelme gözlenmiştir. Anahtar Kelimeler: Elektrokromism, gözenekli WO3 filmler, iyon giriş-çıkış kinetiği, sol-gel, uv aydınlatma.In this study, standard and mesoporous sol-gel WO3 thin films were prepared by a spin coating technique from an ethanolic solution of tungsten hexachloride (WCl6). Different types of polymers were employed as a template to generate the mesoporous structure. These polymers: (BASFTM Pluronic p123) (p1), poly(ethylene glycol) (p2), polyethylene glycol-ran-propylene glycol (p3) and polystyrene-co-allyl-alchl (p4). To avoid the varying degrees of crystallinity as a result of thermal treatment, a UV illumination method has been employed to remove the polymer surfactant. This room temperature approach uses ozone generated during UV illumination in air to oxidize the organic compounds. The electrochromic and optical properties of the mesoporous films are described and compared to standard sol-gel WO3 films. Results are also presented on the samples prepared by thermal treatment. We demonstrate that the UV illumination treatment is a superior method to remove templates which enables us to more effectively investigate the effect of mesoporosity on the electrokinetics of ion insertion into WO3 films. These mesoporous materials exhibit superior high rate ion-insertion performance when used as electrochromic layers, which is attributed to the high surface area of mesoporous WO3. The films were characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), ellipsometre and cyclic voltammetry. Keywords: Electrochromism, insertion kinetics, mesoporous WO3 films, sol-gel, uv illumination
Müşteri İlişkileri Yönetiminde etkinliği arttırmak için bir bulanık model önerisi
Get PDFBu çalışmada, dünya çapında yoğun bir ilgi görmekte olan Müşteri İlişkileri Yönetimi (MİY) uygulamalarının performans ölçümünü sağlamak amacıyla sayısal bir model önerilmiştir. Kurumsal Karne kavramı temelinde geliştirilen ölçüm modelinde, MİY ölçümünün 4 boyutta gerçekleşmesi önerilmektedir. MİY çıktıları boyutunda, firmanın MİY çalışmalarından beklediği temel faydalar yer almaktadır. Müşteri boyutu ise, müşterilerin firmaya karşı olan tutumunu ifade etmektedir. Süreçler boyutu, firmaların müşteri ile olan ilişkilerini yönettikleri süreçlerin ölçümünü içermektedir. Altyapı boyutu ise kurum kültürü, organizasyonel uyum ve teknoloji gibi MİY çalışmalarına yardımcı olan öğeleri barındırır. Oluşturulan mantıksal ilişki haritaları, Bulanık Analitik Ağ Süreci ile sayısallaştırılmıştır. Böylece temel boyutlar arasındaki ilişkiler göz ardı edilmeden bütünsel bir MİY başarı notu elde edilmesi sağlanmıştır. Ölçüm modelinde yer alan göstergelerin bir kısmı literatürden adapte edilirken, süreçler boyutunun ölçümü ile ilgili istatistiki bir çalışma gerçekleştirilmiştir. Bu çalışma ile MİY süreçlerinin yedi temel fonksiyon ile ölçümlenebileceği belirlenmiştir. Bunlar; Müşteri Hedefleme, Müşteri Tanıma, Ürün/Hizmet Özelleştirme, Müşteri Genişletme, Tavsiye Yönetimi, Müşteri Yeniden Kazanma ve İlişki bitirme süreçleri olarak tespit edilmiştir. Faktör analizi ile belirtilen süreçlerin ölçümünde kullanılabilecek 31 soruluk bir ölçü oluşturulmuş ve bu ölçü kullanılarak süreçlerin firma içinde yer alan alt yapı öğeleri, müşteri tatmin ve müşteri sadakati ve ekonomik performans ile olan ilişkileri incelenmiştir. Anahtar Kelimeler: Müşteri İlişkileri Yönetimi, performans, bulanık mantık, ANP.Customer Relationship Management (CRM), has been a new paradigm for business success. As a result of the promised outcomes, a huge amount of investment is done in CRM. But the result of these investments rarely fulfills the expected outcomes. In this study a model for performance measurement of Customer Relationship Management (CRM) is proposed, in order to maintain enhance the effectiveness of CRM. In this manner, a measurement model is developed basing on previous Balanced Scorecard studies. The model has two major steps. In the first step a causal map is developed which describes the cause and effect relationship between the major CRM concepts. The map is developed based on the current CRM literature and is confirmed by the CRM professionals. Four perspectives are proposed to be used in the model. The CRM outputs perspective is composed of the main goals of CRM. Customer Perspective covers the attitudes of the customers towards the company as a preliminary sign of the future behaviors. The process perspective covers the process that companies use to manage the relations with the customers. The Infrastructure perspective is composed of organizational alignment, organizational culture and technology which supports the CRM implementations and customer processes. The studies in second step of the model are concerned with quantifying the performance measures. In the manner, firstly the measures that will be used in the CRM components are selected for the case study. The goal for the measures and the minimum potential values for each measure is decided. These values are utilized in normalization formulas in order to convert the observed values of the measure to measure scores. Current CRM and performance literature sheds light on the measures that can be used in model. So most of the measures allocated in the model is adapted from the current literature. On the other hand, a new scale is developed for the process perspective. The steps that are proposed by Churchill (1979) and Devellis (2003) are followed to maintain the measurement scale. After defining the items depending on the CRM literature and confirming them with the professionals a survey is established. 167 useable survey responses are collected. Explanatory factor analysis with principle component analysis and varimax rotation is allocated for the analysis. As a result 7 major factors, that have eigen value higher than 1 are reached. As a result the customer process are found as; targeting, getting to know, customization, expending the customer, referrals management, win back and terminating the relationship. After the item purification, a measure that is composed of 31 questions is maintained. The measure is utilized in order to define the relationship between, infrastructure components, customer satisfaction and organizational performance. The results of the finding of the analysis support the proposed causal maps. At the final step, Fuzzy Analytical Network Process (F-ANP) is allocated in order to find the global performance. As the causal map defines there is dependence between the perspectives. Analytical Network Process is a method enables to model the problem as a hierarchy and take the dependence between the components. In order to find the relative weights of the components, the pair wise comparison matrixes for the perspectives, components and the dependence between the perspectives are formed. Using Buckley (1985)'s fuzzy analytical hierarchy process procedures with triangular fuzzy numbers, the weights of the perspectives and the components are calculated. Multiplying the result of the each measure with the related weight and summing the results; an overall numeric value is reached that represents the both overall and performance of each perspective. As a result the model provides the firms a framework that can be used to track the performance of the CRM implementations. The model both provides an overall performance value and the value of each perspective. Using the model, firms can define the areas that needs to be improved and tracks the effects of the current CRM activities within the company. Keywords: Customer Relationship Management, performance, customer process measurement
Video dizilerindeki araç plakalarının FE-Yoğunlaştırma algoritması kullanılarak izlenmesi
Get PDFAutomated vehicle identification (AVI) is still an important research issue and drawing attention in machine vision community. Its potential commercial applications are automatic barrier systems, automatic payment of parking or highway toll fee, automatic locating of a stolen vehicle, automatic calculation of traffic volume and so on. License plate enables us to identify a vehicle and its owner. License plate recognition is the most effective method for identification of the vehicle. A suitable and promising solution to vehicle identification is visual recognition of the license plate from camera view. This approach is applicable because it does not require vehicles to carry additional equipment such as special RF transmitters. Without additional cost, these systems are capable of installation to the field. But visual license plate detection and recognition is a very difficult task. It is quite a challenging problem because vehicles are running in an outdoor environment, where lighting conditions can change rapidly, weather conditions can cause poor image quality, license plates can be dirty or in poor condition and occlusions can occur frequently. Therefore, Visual License Plate Recognition (VLPR) systems may fail because of uncontrollable external conditions. Beside the challenging nature of the problem, the high-dimensional nature of the VLPR problem may impose a significant computational load on the target processing platform. The aim of this work is 3D tracking of license plate in order to determine the state (spatial position and 3D orientation) of the license plate from sequential frames of the video. This can be accomplished in a brute force way by testing every possible orientation and translation and then selecting the one that best fits the current frame. If all six degrees of spatial freedom of the object are to be determined, the state space of the object is six dimensional. Setting the number of possible values of each degree of freedom to 100, the task of tracking by brute force then requires 1006 comparisons of a state with the image data. Even with such a limited resolution and a six dimensional feature space it is clear that, it is computationally impossible to perform tracking in real time by brute force. That is where stochastic tracking is meaningful. A stochastic process is one whose behaviour is non-deterministic in that the next state of the environment is partially but not fully determined by the previous state of the environment. Instead of comparing every possible configuration of the object with each video frame, the idea behind stochastic tracking is to make a set of guesses of the state, compare these guesses with the current frame, and use the result of this comparison as the basis for a new set of guesses when the next frame comes. The new guesses are made by selecting the best guesses from the last frame and applying a model of the movement of the object from one frame to the next. The set of guesses (called particles or samples) will frame by frame converge around the correct state of the object. In recent years, there has been a great interest in applying Particle Filtering to computer vision problems. This specialized Particle Filtering method for computer vision problems is introduced as Condensation or Sequential Importance Sampling. Condensation algorithm utilizes factored sampling and given dynamic models to propagate an entire probability distribution for object's position and shape over time. It can perform successfully robust tracking of object motion. On the other hand, its convergence greatly depends on the trade off between the number of particles/hypotheses and the fitness of the dynamic model. For example, in cases where the dynamics are complex or poorly modelled, thousands of samples are usually required for realapplications. In order to improve the performance of the Condensation algorithm, DE-Condensation algorithm is proposed, which is an integration of the Differential Evolution and Condensation algorithms. DE-Condensation algorithm is utilized for spatial position estimation and tracking of license plates in 3D from monocular camera view. The performance and computational load of the Extended Kalman filter, Condensation Algorithm, DE-Condensation algorithm and Genetic Condensation algorithm are compared for evaluating DE-Condensation Algorithm's performance. Keywords: License Plate Tracking, Condensation, DE-Condensation. Bu çalışmanın amacı, araç plakalarının üç boyutlu uzayda konum ve yöneliminin bulunması için video görüntüsünden izlenmesidir. Eğer nesnenin altı dereceli uzay serbestliği belirlenmek isteniyorsa, durum uzayı altı boyutlu olur. Her serbestlik derecesi için olası değerler kümesini 100 elemanlı kabul edersek, bu nesneyi her olası durumu deneyerek izleyebilmek için görüntü verisi üzerinde 1006 karşılaştırma yapmamız gerekmektedir. Bu sınırlı çözünürlük ve altı dereceli serbestlik uzayında dahi, bu şekilde gerçek zamanlı izleme yapmanın mümkün olmadığı açıktır. Stokastik izlemenin ardında yatan düşünce, her olası nesne durumunu denemek yerine, durum hakkında tahminlerde bulunmak ve bu tahminleri o anki video karesi ile karşılaştırarak sonuçları bir sonraki video karesi için tahmin yapmakta kullanmaktır. Son yıllarda, bilgisayar ile görüntü işleme problemlerinde Parçacık Filtreleri’nin kullanımına yönelik bir ilgi görülmektedir. Bilgisayar ile görüntü işleme problemlerinde kullanılan özel Parçacık Filtresi’ne Yoğunlaştırma algoritması veya Ardışıl Önem Örnekleme denmektedir. Bu yöntem hareketli nesneler için gürbüz bir izleme olanağı sunmaktadır. Öte yandan, bu algoritmanın yakınsaması büyük oranda parçacık sayısı ve dinamik modelin doğruluğu arasındaki ilişkiye bağlıdır. Bu tezde Yoğunlaştırma algoritmasını iyileştirmek amacıyla FE-Yoğunlaştırma algoritması önerilmektedir. Bu algoritma Farksal Evrim ve Yoğunlaştırma algoritmalarının bir birleşimidir. FE-Yoğunlaştırma algoritması üç boyutlu uzayda tek bir kamerayla araç plakası konum ve yöneliminin izlenmesi için kullanıldı. Genişletilmiş Kalman filtresi, Yoğunlaştırma, Genetik Yoğunlaştırma ve FE-Yoğunlaştırma algoritmalarının izleme başarımları karşılaştırıldı. FE-Yoğunlaştırma algoritması diğer üç algoritmaya göre çok daha iyi başarım göstermektedir. Anahtar Kelimeler: Araç plakası izlenmesi, yoğunlaştırma, FE-Yoğunlaştırma
A novel MEMS based batteryless active RFID system
Get PDFBu makalede yeni bir titreşim temelli mikro enerji harmanlayıcı sistemi önerilmiştir. Titreşimler ve ani hareketlerin, mekanik yapının sadece eğilmesine değil aynı zamanda gerilmesine yol açması prensibine dayanarak, sistemin doğrusal olmayan bölgede çalışması sağlanmıştır. Tasarlanan ve modellemesi yapılan mekanik yapının üzeri ince bir piezoelektrik film tabakası ile kaplanmış ve bu tabaka üzerinde oluşan mekanik stres elektrik enerjisine çevrilerek devreleri beslemek için kullanılmıştır. Doğrusal olmayan bölgede çalışmanın, mikrowatt mertebesindeki güç seviyelerini mm3’lük aletlerle elde edebileceği göz önüne alındığında, güneş panellerinde elde edilen güç yoğunlukları kadar yüksek enerjilerin elde edilebileceği görülmüştür. Algılayıcı kabiliyeti sayesinde bilgi depolayabilen, kum tanesi büyüklüğünde olan ve üretiminde kullanılan temel malzeme silikon olan bu aletler “zeki kum” olarak isimlendirilmiştir. Mekanik yapının modellenmesi ve tasarımı geliştirilmiş ve üretim sonuçları da ayrıca verilmiştir. Sistemin bilgi gönderebilmesi ve alabilmesi amacıyla iyi bilinen RFID teknolojisi tabanlı bir kablosuz haberleşme yöntemi önerilmiştir. Bu bağlamda, paket taşımacılığında sürekli ivme denetleme, sınır güvenliği için kendinden beslemeli algılayıcılar, çabuk bozulan yiyeceklerin taşımacılığında sıcaklık denetleme ve pilsiz kalp atışı algılayıcı gibi birçok uygulama önerilmiştir. RFID devrelerinin tasarımı yapılmış ve benzetim sonuçları elde edilmiştir. Oku-yaz bellek olarak manyetik belleklerden yararlanılmıştır. Bu sayede, pil kullanılmadan aktif bir şekilde veri yazabilen bir sistem yaratılmıştır. “Zeki RFID” olarak isimlendirilen bu sistemde ayrıca bilginin iletimi için de yeni bir modülasyon yöntemi önerilmiştir. Anahtar Kelimeler: Enerji harmanlayıcı, RFID, mikroelektronik, MEMS.In this paper, a novel, vibration based micro energy harvester system has been proposed. The modeling, design and fabrication of the devices have been carried out. There are several propositions in this work. The biggest claim is to achieve high power density levels with a mm3 device by using a novel vibration based mechanical structure. The operating regime is nonlinear unlike its conventional counterparts, which yields to generate more electrical energy. The proposed packaging method of the device is very simple and easy to realize. Furthermore, a wireless communication scheme based on the well-known RFID (Radio Frequency Identification) technology has also been proposed. The mechanical structure of the device is based on a clamped-clamped beam where four tethers share a thick proof mass. The proof mass is used in order to bring the first eigenfrequency of the system below 50Hz which enlarges the operating frequency range. The surface of the proof mass also acts as a platform for the sensor circuits. Vibrations or sudden movements cause the mechanical structure do not only bend but also stretch, thus working in non-linear regime. The piezoelectric thin film layer on the silicon tethers converts the mechanical stress into the electrical energy. Microwatts of power can be achieved with a mm3 device which yields a high power density levels on the order of the solar panels. This device is named 'smart sand', because it has sensor capabilities that can store information, its size is almost a sand grain and the main material used for the fabrication is silicon. The modeling and design of the mechanical structure has been developed by using COMSOL" (a finite element analysis (FEA) tool) and SIMULINK" (an extension tool of MATLAB). Firstly, the stress levels have been calculated and the transient response of the structure has been investigated. Then, the theoretical analysis has been combined with these two tools and expected power density levels have been found. The fabrication of the "smart sand" has also been developed in this work. Bulk micromachining techniques have been used in order to form the proof mass. The piezoelectric thin film layer has been deposited onto the tethers by sol-gel method. Electrodes of the piezoelectric layer have been fabricated by the lift-off process. The packaging has been embedded into the fabrication process which reduced the handling issues during the process. An elastomer (poly dimethyl siloxane, PDMS) which is very easy to pattern, handle and cheap has been used for the packaging which has not been tried before. The "smart sand" serves as a typical accelerometer which senses the continuous vibrations or sudden accelerations. In order to further develop the sensor capabilities of the system, a new approach has been proposed which is called the "smart RFID" platform where the device has been combined with the RFID concept. In this context, an RFID transponder has been designed. The circuitry has the capabilities of sending and receiving 64 bits of data. The 64-bit memory has been constructed with the magnetic random access memory (MRAM) cells. Few bits have been reserved for the acceleration or temperature data. When a sudden or continuous acceleration happen, the "smart sand" generates voltage and this voltage is used to write the memory bits without the need of a battery. Therefore, the "smart RFID" platform behaves like a batteryless active RFID transponder. In order to determine whether the adequate voltage level is reached or not, a mechanical relay has been proposed and its design has been investigated. Other bits are used for standard identification and they are written or read via an external reader. The frequency of operation has been chosen 2.45GHz. Several applications have been proposed that is possible to use the "smart RFID" platform; such as continuous acceleration monitoring in package delivery, self-powered sensors for homeland security, temperature monitoring of the perishable food item delivery and a batteryless heart rate sensor. Their feasibilities have been investigated and discussed.The applications can be further enhanced and new application alternatives can be developed. The proposed RFID platform has been designed and simulated. All sub-blocks have been designed and the results have been given. In addition to the standard circuit designs, a new modulation technique has been proposed and simulated. This technique eases the data and clock recovery circuits. Keywords: Energy Harvester, RFID, Microelectronics, MEMS.
Evaluating the efficiencies of alternative energy resources for electricity generation in Turkey
Get PDFBirden çok girdi ve çıktıya sahip karar birimlerinin göreli performanslarının ölçülmesi için kullanılan klasik Veri Zarflama Analizi (VZA) modellerinde yalnızca kesin sayısal veriler kullanılabilir. Oysa gerçek hayattaki birçok uygulamada karar birimlerinin kullanıldığı girdiler ve ürettiği çıktılar belirsiz, aralıklar halinde veya sözel olarak ifade edilmiş olabilir. Enerji kaynak alternatiflerinin etkinlik analizindeki uzman görüşleri sözel olarak, maliyet girdisi de belirsiz olduğu için bulanık sayılarla ifade edilmektedir. Bu çalışmada, Türkiye’de elektrik üretimi için kullanılabilecek enerji kaynak alternatiflerinin etkinliğinin ölçülmesi için Bulanık VZA (BVZA) kullanılmıştır. Makalede, Charnes vd. (1978) tarafından geliştirilen klasik VZA modelinin (CCR modeli) dual formunu temel alan yeni bir bulanık VZA formülasyonu (Dual Bulanık Veri Zarflama analizi–DBVZA) önerilmektedir. Bulanık model, α-kesmeleri yaklaşımı kullanılarak doğrusallaştırılmıştır. DBVZA modelinde, diğer bulanık VZA modellerinden farklı olarak, Karar Birimlerinin (KB) etkinliği ölçülürken, bulanık girdi ve çıktı değerlerinin α-kesmelerinin uç noktaları yerine, tüm α-kesmeleri performans ölçümünde kullanılmakta ve böylelikle aralığın içindeki verilerin de etkinlik analizinde dikkate alınması sağlanmaktadır. DBVZA’nın karar vericilere sağladığı bir diğer avantaj, tüm α seviyelerinde etkinlik sınırında yer alan, bir başka deyişle %100 etkin olan KB sayısının diğer bulanık VZA yöntemlerine göre düşük olmasıdır. Bu durum KB’lerin etkinliklerine göre sıralanmasını kolaylaştırmaktadır. Ayrıca DBVZA ile yapılan uygulamalarda karar birimlerinin etkinliklerine göre sıralanabilmesi için herhangi bir bulanık sıralama yöntemine ihtiyaç duyulmamaktadır. Anahtar Kelimeler: Veri zarflama analizi, bulanık matematik programlama, etkinlik analizi, enerji alternatifleri, elektrik üretimi.With the beginning of 21st century, the consumption of energy all over the world is increasing far more rapidly than in the last century. Today, energy is the most important basic input for economical and industrial development. Especially for developing countries like Turkey, alternative energy resources for power plants have very high strategic importance. In Turkey, like many other countries, the generation of electric power is based on fossil fuels. The volatility of oil prices, the exhaustibility of fossil fuels and environmental issues force developing industries to revise their alternatives for electricity generation. Now, it is the time to give more attention to stable, reliable and non-polluting energy resources. Most forms of alternative energy resources are dependent on geographical and environmental factors which vary from country to country. Every country has to determine its energy policy considering its specific conditions like demand and supply equilibrium, dependency on other countries, geographical conditions, variations of population, etc.Turkey is a country that lacks sufficient conventional energy resources and is importing oil and natural gas from other countries. As an emerging country, Turkey has been one of the fastest growing energy markets in the world. Turkey's share in total OECD production is expected to increase from 2% in 1995 to 7% in 2020s, making Turkey a significant economic power within the OECD countries but this will be possible only with a proper energy policy and efficient selection of alternative energy resources. Selecting among different resource alternatives is a very difficult task as the factors which affect the efficiency of energy resources are imprecise and require expert knowledge. The criteria, such as sustainability, security etc. are defined in linguistic form as it is impossible to quantify them. As a result, some of the criteria of efficiency have to be introduced in analysis as fuzzy data. The performance assessment methods which enable us to use fuzzy inputs and outputs are suitable for the evaluation of energy alternatives efficiencies. The potentially viable electricity resources considered for Turkey are oil, coal, natural gas, nuclear power, hydropower, wind power, solar power and biomass power. For the evaluation criteria of these energy resources and their values, we refer to expert opinions. The details about efficiency criteria and results of the analysis can be found in the application. The energy resources are ranked by their efficiency scores as follows: Wind, natural gas, hydropower, biomass, coal, oil, solar power and nuclear power. The existing data envelopment analysis (DEA) models for measuring the relative efficiencies of a set of decision making units (DMUs) using various inputs to produce various outputs are limited to crisp data. However, the data acquired from expert opinions for evaluating the efficiencies of alternative energy resources is generally in linguistic form. This paper proposes a fuzzy DEA formulation based on dual form of the DEA model developed by Charnes et al. (1978) to deal with imprecise or linguistic data that we frequently come across in real-world applications. The model is transformed into a family of crisp linear problems using the "-cut approach. In dual fuzzy DEA formulation, the entire "-cut interval is taken into account unlike many other fuzzy DEA formulations which use the boundary points of "-cuts when calculating the efficiency scores of DMUs. Dual fuzzy DEA is suitable to rank every DMU in all "-levels as we are not faced with the problem of having too many DMUs on the efficient frontier. Another advantage of the dual fuzzy DEA formulation is that, it does not require any fuzzy ranking method to rank the DMUs. As the result, dual fuzzy DEA can be very useful in performance evaluation, especially when decision makers or researchers have few DMUs and a large number of decision criteria (inputs and outputs) as they will be able to rank all DMUs according their efficiency scores. The paper is organized as follows: A literature survey of fuzzy DEA models is followed by the presentation of the classical DEA model (CCR formulation), dual form of the CCR formulation and fuzzy DEA model. Then, the linearization of dual fuzzy DEA by ?-cut approach and variable alterations is introduced. After a real life application concerning the assessment of energy alternatives for electricity production in Turkey, the paper ends with the conclusion. Keywords: Data envelopment analysis, fuzzy mathematical programming, efficiency analysis, energy alternatives, electricity generation
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