In this thesis, the development and implementation of fluorescence lifetime imaging microscopy that integrates time correlated single photon counting (TCSPC) and a confocal microscope will be described. The TCSPC method has high detection efficiency, with a time resolution limited only by the transit time spread of the detector, and directly delivers the decay functions in the time domain. TCSPC can also be used to obtain images that indicate the fluorescence resonance energy transfer (FRET) effect between critical fluorophores, an important method distinguish the difference between binding and co-localization. Estimation of distances between RET fluorophore pairs can also be established. Additionally, the effects of ion concentration, oxygen concentration, pH value, ..etc. can also be revealed.

Credit risk is one of the major risks banks and financial institutions are faced with. With the New Basel Capital Accord, banks and financial institutions have the opportunity to improve their risk management process by using Internal Rating Based (IRB) approach. In this thesis, we focused on the internal credit rating process. First, a short overview of credit scoring techniques and validation techniques was given. By using real data set obtained from a Turkish bank about manufacturing firms, default prediction logistic regression, probit regression, discriminant analysis and classification and regression trees models were built. To improve the performances of the models the optimum sample for logistic regression was selected from the data set and taken as the model construction sample. In addition, also an information on how to convert continuous variables to ordered scaled variables to avoid difference in scale problem was given. After the models were built the performances of models for whole data set including both in sample and out of sample were evaluated with validation techniques suggested by Basel Committee. In most cases classification and regression trees model dominates the other techniques. After credit scoring models were constructed and evaluated, cut-off values used to map probability of default obtained from logistic regression to rating classes were determined with dual objective optimization. The cut-off values that gave the maximum area under ROC curve and minimum mean square error of regression tree was taken as the optimum threshold after 1000 simulation. Keywords: Credit Rating, Classification and Regression Trees, ROC curve, Pietra Index

Contemporary approach performance based engineering generally relies on the approximate procedures that are based on the use of capacity curve derived from pushover analysis. The most important parameter in the displacement-based approach is the inelastic displacement demand computed under a given seismic effect and the most common procedures employed for this estimation / the Capacity Spectrum Method and the Displacement Coefficient Method are based on bi-linearization of the capacity curve. Although there are some recommendations for this approximation, there is a vital need for rational guidelines towards the selection of the most appropriate method among several alternatives. A comprehensive research has been undertaken to evaluate the influence of several existing alternatives used for approximating the capacity curve on seismic demands. A number of frames were analyzed under a set of 100 ground motions employing OpenSees. In addition, the pushover curves obtained from nonlinear static analyses were approximated using several alternatives and the resulting curves were assigned as the force-deformation relationships of corresponding equivalent single-degree-of-freedom systems. These simplified systems were later analyzed to compute the approximate seismic response parameters. Using the results of the complex and simplified analyses, the performance of each approximation method was evaluated in estimating the &amp / #8216 / exact&amp / #8217 / inelastic deformations of the multi-degree-of-freedom systems at various degrees of inelasticity. Dependency of the errors on ductility, strength reduction factor and period was also investigated. The interpretations made and the conclusions drawn in this study is believed to clarify the rationality and accuracy of selecting the appropriate idealization of the capacity curve.

Architectural curvilinear form has been on the scene since the time of the first building shelters. Curve is the most common form in nature. This phenomenon inspired human beings while they are building structures. Curvilinear form has developed over centuries, via structural enhancements and aesthetic tenets. A symbolic meaning is tailored to curvilinear structures such as use of domes in religious buildings. However, the difficulties in the construction process of these forms have been a challenge for people throughout the history. Today, introduction of computer aided design and manufacturing technologies into building industry encourages the use of curvilinear forms in architecture. This study intends to explore the relationship between structure and architectural curvilinear form. The curvilinear form will be examined basically according to its structural potentials through its geometrical configuration. A computer model of the roof of Channel Tunnel Railway Terminal at Waterloo is generated and with some geometrical modifications for the configuration of the roof, new schemes of structures are obtained. An analytical comparison of structural behavior and efficiency is made via the computer model of the roof and these modified configurations.

In this study, semi-distributed hydrological model studies were carried out with the Mike11 model in Yuvacik dam Basin. The basin with a drainage area of 257.8 km2 is located in 12 km South East of Izmit city in T&uuml / rkiye. The basin is divided into three sub-basins named as Kirazdere, Kazandere and Serindere where each sub-basin is represented by its own characteristics. The largest peaks of inflow were observed when the storm events occur due to both snowmelt and rain. Therefore, observed flows for the period of 2001-2006 were grouped as daily and hourly storm events according to the event types such as rainfall, snowmelt or mixed events. Rainfall- Runoff Model (NAM) module of the model was used for the simulation of daily snowmelt and rain on snow events and Unit Hydrograph Method (UHM) module was used for the simulation of hourly rainfall events. A new methodology is suggested for the determination of Curve Number (CN) of the sub-basins by using the fractional area and topographic index values combined with hourly model simulations. The resulting CN values were used in the UHM module v and the suggested CN approach has been validated with the classical SCS-CN approach with GIS analysis. As a result of the study, the parameters of each sub-basin are calibrated with hourly and daily model simulations. The resulting flows are compared with the observed flows where model efficiency is tested with visual and statistical evaluations. The modeling studies give promising results for the computation of runoff during different seasons of a year.

This study analyzes the J-curve effect for Turkey&rsquo / s bilateral trade with her three main trading partners / Germany, USA and Italy, for consumption, capital and intermediate goods. The bounds test is used to test for cointegration among the trade balance, the real bilateral exchange rate, the real domestic income and the real foreign income. The results show that the real exchange rate is not a significant determinant of trade in the short run. In the long run, it is significant only for trade with USA in consumption goods. Moreover, J-curve does not exist for Turkey&rsquo / s bilateral trade with Germany, USA, and Italy in consumption, capital and intermediate goods. The results support existence of a link between the bilateral trade balances and the real domestic income both in the short run and the long run.

Turkish Electricity Market is modeled as a non-cooperative game with complete information in order to simulate the behavior of market participants and analyze their possible strategies. Player strategies are represented with multipliers in a discrete strategy set. Different market scenarios are tested through different game settings. As the novelty of this thesis, similar market participants are clustered and treated as single players in order to apply game theory in an efficient way. Generators are clustered using Agglomerative Hierarchical Clustering and Square Sum of Deviations is used as the proximity measure. The game is constructed with three players that reflect the main characteristics of the market participants. Clusters and game scenarios are constructed using the real market data of the Turkish Electricity Market at four different time points in 2008 and results are compared. Clustering results reflect the actual installed capacity distribution based on the main companies and fuel types in Turkish Electricity Market. According to four games of clustered electricity generators, when there is not enough competition in the market, dominant player is advised to submit bids with lower price for energy surplus cases and offers with higher price for energy deficit cases. However, when there is competition in the market, players are advised to submit offers with lower price in order to take a share of the limited demand for up-regulation.

Recent devastating earthquakes revealed that bridges are one of the most vulnerable components of the transportation systems. These seismic events have emphasized the need to mitigate the risk resulting from the failure of the bridges. Depending on the seismicity of the bridge local site, seismic vulnerability assessment of the bridges can be done based on the fragility curves. These curves are conditional probability functions which give the probability of a bridge attaining or exceeding a particular damage level for an earthquake of a given intensity level. In this dissertation, analytical fragility curves are developed for the ordinary highway bridges in Turkey constructed after the 1990s to be used in the assessment of their seismic vulnerability. Bridges are first grouped into certain major bridge classes based on their structural attributes and sample bridges are generated to account for the structural variability. Nonlinear response history analyses are conducted for each bridge sample with their detailed 3-D analytical models under different earthquake ground motions having varying seismic intensities. Several engineering demand parameters are employed in the determination of seismic response of the bridge components as well as defining damage limit states in terms of member capacities. Fragility curves are obtained from the probability of exceeding each specified damage limit state for each major bridge class. Skew and single-column bent bridges are found to be the most vulnerable ones in comparison with the other bridge classes. Developed fragility curves can be implemented in the seismic risk assessment packages for mitigation purposes.

The representation of field elements has a great impact on the performance of the finite field arithmetic. In this thesis, we give modified version of redundant representation which works for any finite fields of arbitrary characteristics to design arithmetic circuits with small complexity. Using our modified redundant representation, we improve many of the complexity values. We then propose new representations as an alternative way to represent finite fields of characteristic two by using Charlier and Hermite polynomials. We show that multiplication in these representations can be achieved with subquadratic space complexity. Charlier and Hermite representations enable us to find binomial, trinomial or quadranomial irreducible polynomials which allows us faster modular reduction over binary fields when there is no desirable such low weight irreducible polynomial in other representations. These representations are very interesting for the NIST and SEC recommended binary fields GF(2^{283}) and GF(2^{571}) since there is no optimal normal basis (ONB) for the corresponding extensions. It is also shown that in some cases the proposed representations have better space complexity even if there exists an ONB for the corresponding extension.

This study focuses on the evaluation of seismic safety of masonry buildings in Turkey by using fragility curves. Fragility curves for masonry buildings are generated by two behavior modes for load bearing walls: in-plane and out-of-plane. By considering the previous research and site investigations, four major parameters have been used in order to classify masonry buildings with in-plane behavior mode. These are number of stories, strength of load-bearing wall material, regularity in plan and the arrangement of walls (required length, openings in walls, etc.). In addition to these four parameters, floor type is also taken into account for the generation of fragility curves by considering out-of-plane behavior mode. During generation of fragility curves, a force-based approach has been used. In this study there exist two limit states, or in other words three damage states, in terms of base shear strength for in-plane behavior mode and flexural strength for out-of-plane behavior mode. To assess the seismic vulnerability of unreinforced masonry buildings in Turkey, generated fragility curves in terms of in-plane behavior, which is verified by damage statistics obtained during the 1995 Dinar earthquake, and out-of-plane behavior, which is verified by damage statistics obtained during the 2010 Elazig earthquake, is combined. Throughout the analysis, ground motion uncertainty, material variability and modeling uncertainty have also been considered. In the final part of the study, a single-valued parameter, called as &lsquo / vulnerability score&rdquo / , has been proposed in order to compare the seismic safety of unreinforced masonry buildings in Fatih sub province of Istanbul and to assess the influence of out-of-plane behavior together with the in-plane behavior of these existing masonry buildings.