Multiple Signal Classification (MUSIC) Algorithm based and Wigner Distribution-Principal Component Analysis (WD-PCA) based classification techniques are very recently suggested resonance region approaches for electromagnetic target classification. In this thesis, performances of these two techniques will be compared concerning their robustness for noise and their capacity to handle large number of candidate targets. In this context, classifier design simulations will be demonstrated for target libraries containing conducting and dielectric spheres and for dielectric coated conducting spheres. Small scale aircraft targets modeled by thin conducting wires will also be used in classifier design demonstrations.

Distributed generation (DG) is electricity generation by small generating units, which are interconnected at distribution level with capacity less than 50 MW. Environmental concerns and the idea of using cheap and domestic renewable resources increased the popularity of DG following the developments in equipment technology. In Turkey, interconnection of DG is realized through the distribution busbars of 154/36 kV substation. The interconnection of DG at 36 kV feeders is not allowed by distribution system authority. This thesis proposes an interconnection rule which includes technical analyses to be conducted before the permission of interconnection of DG at 36 kV feeders. Moreover, the protection functions and operational requirements needed for the proper and safe operation of distribution system in presence of DG are introduced. A sample distribution system with relevant parameters is used for the simulation studies in Digsilent software. In order to determine the operational reserve requirement against the variations in wind generation, a statistical method including Weibull distribution, standard deviation and monthly average wind speeds is used. Convenience of hydropower plants&rsquo / response for being backup generation against the fluctuations in wind generation is analyzed by a mid-term dynamic model of the power system. A secondary control mechanism for the integration of wind power is suggested. Finally, an economic comparison between the interconnection alternatives of hydropower and photovoltaic power plants at the distribution busbar of the 154/36 kV substation and the 36 kV feeder is done by present worth analysis using the up to date power plant costs and incentives.

Radar systems have been very effective in gathering information in a battlefield, so that the tactical actions can be decided. On the contrary, self-protection systems have been developed to break this activity of radars, for which radar signals must be intercepted to be able to take counter measures on time. Ideally, interception should be done in a certain time with a 100% probability, but in reality this is not the case. To intercept radar signals in shortest time with the highest probability, a search strategy should be developed for the receiver. This thesis studies the conditions under which the intercept time increases and the probability of intercept decreases. Moreover, it investigates the performance of the search strategy of Clarkson with respect to these conditions, which assumes that a priori knowledge about the radars that will be intercepted is available. Then, the study identifies the cases where the search strategy of Clarkson may be not desirable according to tactical necessities, and proposes a probabilistic search strategy, in which it is possible to intercept radar signals with a specified probability in a certain time.

This thesis investigates the significant factors affecting municipal solid waste (MSW) generation in Turkey. For this purpose, both spatial and non-spatial tech&not / niques are utilized. Non-spatial technique is ordinary least squares (OLS) regression while spatial techniques employed are simultaneous spatial autoregression (SAR) and geographically weighted regression (GWR). The independent variables include socio-economic, demographic and climatic indicators. The results show that nearer provinces tend to have similar solid waste generation rate. Moreover, it is shown that the effects of independent variables vary among provinces. It is demonstrated that educational status and unemployment are significant factors of waste generation in Turkey.

ABSTRACT A GENETIC ALGORITHM FOR p-HUB CENTER PROBLEM WITH STOCHASTIC SERVICE LEVEL CONSTRAINTS Eraslan Demirci, S&uuml / kran M.Sc., Department of Industrial Engineering Supervisor: Asst. Prof. Dr. Sedef Meral December 2010, 170 pages The emphasis on minimizing the costs and travel times in a network of origins and destinations has led the researchers to widely study the hub location problems in the area of location theory in which locating the hub facilities and designing the hub networks are the issues. The p-hub center problem considering these issues is the subject of this study. p-hub center problem with stochastic service level constraints and a limitation on the travel times between the nodes and hubs is addressed, which is an uncapacitated, single allocation problem with a complete hub network. Both a mathematical model and a genetic algorithm are proposed for the problem. We discuss the general framework of the genetic algorithm as well as the problem-specific components of algorithm. The computational studies of the proposed algorithm are realized on a number of problem instances from Civil Aeronautics Board (CAB) data set and Turkish network data set. The computational results indicate that the proposed genetic algorithm gives satisfactory results when compared with the optimum solutions and solutions obtained with other heuristic methods.

In this thesis, transverse vibration of a cracked beam on an elastic foundation and the effect of crack and foundation parameters on transverse vibration natural frequencies are studied. Analytical formulations are derived for a beam with rectangular cross section. The crack is an open type edge crack placed in the medium of the beam and it is uniform along the width of the beam. The cracked beam rests on an elastic foundation. The beam is modeled by two different beam theories, which are Euler-Bernoulli beam theory and Timoshenko beam theory. The effect of the crack is considered by representing the crack by rotational springs. The compliance of the spring that represents the crack is obtained by using fracture mechanics theories. Different foundation models are discussed / these models are Winkler Foundation, Pasternak Foundation, and generalized foundation. The equations of motion are derived by applying Newton&#039 / s 2nd law on an infinitesimal beam element. Non-dimensional parameters are introduced into equations of motion. The beam is separated into pieces at the crack location. By applying the compatibility conditions at the crack location and boundary conditions, characteristic equation whose roots give the non-dimensional natural frequencies is obtained. Numerical solutions are done for a beam with square cross sectional area. The effects of crack ratio, crack location and foundation parameters on transverse vibration natural frequencies are presented. It is observed that existence of crack reduces the natural frequencies. Also the elastic foundation increases the stiffness of the system thus the natural frequencies. The natural frequencies are also affected by the location of the crack.

Stroke, a major cause of death and disability, is described as interruption or severe reduction of blood flow in cerebral arteries. Oxidative stress plays an important role in the pathogenesis of atherosclerosis and carotid atherosclerosis is a risk factor for stroke. Combination of multiple environmental and genetic risk factors is thought to increase susceptibility to the development of this disease. Therefore, investigation of the polymorphisms of drug metabolizing enzymes is of crucial importance to determine the molecular etiology of the disease. The main objective of this study was to investigate the possible association between polymorphisms of enzymes causing oxidative stress (CYP2E1, FMO3 and NOS3) and enzymes protecting against oxidative stress (GST and NQO1), and the pathogenesis of atherosclerosis and ischemic stroke risk. The study population consisted of 245 unrelated ischemic stroke patients and 145 healthy control subjects. There was no statistically difference between the patient and control groups in terms of age and gender. Hypertension, diabetes, smoking and obesity were found to be at least 2 times more common in stroke patients than controls. While total cholesterol, triglyceride and LDL-cholesterol level were higher in stroke patients, HDL-cholesterol level was lower in stroke patients when compared to controls. In the case-control analyses for the risk of ischemic stroke, CYP2E1*5B mutant allele, *5B was found to be associated with the development of disease (Odds Ratio / OR=7.876, 95%CI=1.025-60.525, P=0.019). In addition, significant difference was observed between stroke patients and controls with respect to CYP2E1*5B genotype distribution (OR=0.869, 95%CI=1.044-62.339, P=0.017). On the other hand, in the NQO1*2 polymorphism, together with NQO1 heterozygote (*1*2), NQO1 homozygote mutant (*2*2) genotype was found protective against ischemic stroke (OR=0.627, 95%CI=0.414-0.950, P=0.027). The risk of hypertensive individuals having stroke was highest in the FMO3 472GA group (OR=6.110, P=0.000). In diabetics, GSTP1 313AG genotype was found to be the highest risk factor for stroke (OR=3.808 P=0.001). On the other hand, NQO1 *1*2 heterozygote genotype was associated with 5 times increased risk for stroke in smokers (OR=5.000, P=0.000). In addition GSTM1 present genotype constituted 8 times increased stroke risk in obese individuals (OR=8.068, P=0.001). Logistic regression analysis revealed that hypertension, diabetes mellitus, obesity and smoking were significant risk factors for stroke. On the other hand, HDL-cholesterol and having NQO1 *1*2 heterozygote genotype were found to be protective factors against stroke.

ABSTRACT A LABORATORY MODEL STUDY ON SETTLEMENT REDUCTION Effect OF STONE COLUMNS IN SOFT CLAY S&uuml / nnetcioglu, Mehmet Emrah M.Sc., Department of Civil Engineering Supervisor: Prof. Dr. Mehmet Ufuk Ergun August 2012, 177 pages An experimental study was conducted in order to examine settlement reduction ratios of footing supported by both floating and end bearing type of stone columns. For the floating types, tests were done with varying column lengths of one and two widths of footing (L=B,2B). Tests were conducted in 200 mm* 200 mm* 200 mm cubic loading tanks. The reinforcement effect was achieved by the installation of four stone columns with 20 mm diameter under 70 mm* 70mm model footing. Parameters such as area replacement ratio (a_s), loading plate dimensions, consolidation and vertical pressures applied, and the relative density (D_R) of the granular column were kept constant, the column length (L) was set as the only variable in the experimental tests conducted. In the tests, footing settlements together with subsurface settlements at depths equal to footing width (B) and two times the footing width (2B) were measured by specially designed telltales. The settlement reduction ratios both at surface and subsurface were evaluated in order to determine the effect of column length on settlement improvement. It has been found out that as the column length increases the settlement reduction ratios decrease for all depth intervals. However, there exists a threshold column length (L=2B), beyond which the composite ground demonstrates little settlement improvement.

The purpose of this study was to investigate the effects of conceptual change oriented instruction accompanied by demonstrations and gender on tenth grade students&rsquo / understanding of gases concepts, and attitudes toward chemistry. Hundred tenth grade students from two classes taught by the same teacher in a public high school were enrolled in the study in the Fall semester of 2003-2004. Control group students were taught by traditionally designed chemistry instruction (TI), while experimental group students were instructed by conceptual change oriented instruction accompanied by demonstrations (CCID). Gases Concept Test and Attitude Scale toward Chemistry were administered to both groups as a pre-test and post-test to assess the students understanding of gases concepts and students&rsquo / attitudes toward chemistry, respectively. Science Process Skills Test was given at the beginning of the study to determine students&rsquo / science process skills. Learning Style Inventory was also given to all students to determine their learning styles. After treatment, interviews were conducted with the teacher and several students from the two groups. The hypotheses were tested by using analysis of covariance (ANCOVA) and two-way analysis of variance (ANOVA). The results showed that CCID caused significantly better acquisition of the scientific conceptions related to gases than TI. There was no significant effect of the treatment on the students&rsquo / attitudes toward chemistry. No significant effect of gender difference on students&rsquo / understanding the concepts about gases and students&rsquo / attitudes toward chemistry was found. Science process skill was determined as a strong predictor in understanding the concepts related to gases.

This thesis studies interactions between coupled acoustic domain(s) and enclosing rigid or elastic boundary. Boundary element-finite element (BE-FE) sound-structure interaction models are developed by coupling frequency domain BE acoustic and FE structural models using linear inviscid acoustic and elasticity theories. Flexibility in analyses is provided by discontinuous triangular and quadrilateral elements in the BE method (BEM), and a rectangular plate and a triangular shell element in the FE method (FEM). An analytical formulation is developed for an extended fundamental sound-structure interaction problem that involves locally reacting sound absorptive treatment on interior elastic boundary. This new formulation is built upon existing analytical solutions for a configuration known as the cavity-backed-plate problem. Results from developed analytical formulation are compared against those from independent BE-FE analyses. Analytical and BE-FE analysis results for a selection of cavity-plate(s) interaction cases are given. Single- and multi-domain BE analyses of cavity-Helmholtz resonator interaction are provided as an alternative to modal method of acoustoelasticity. A discrete-form of the existing BE acoustic particle velocity formulation is presented and demonstrated on a basic case study. Both the existing and the discretized BE acoustic particle velocity formulations could be utilized in acoustic studies. A selection of case studies involving fundamental configurations are studied both analytically and computationally (by BE or BE-FE methods). These studies could provide a basis for benchmark case development in the field of acoustics.