In this thesis, 41 years of bright sunshine duration (SD) data of 192 meteorological stations in Turkey were analyzed. The main objective is to determine the trends of SD data and the importance of such analyses is the high correlation between SD data and solar irradiation reaching the surface of the earth. Because of the missing value problems, only the data set for 72 stations were examined. After imputing missing values of these stations by expectation maximization algorithm, to test the homogeneity Kruskal Wallis test (K-W) and Wald-Wolfowitz runs test for randomness were applied. Only 36 of the stations passed from these homogeneity tests therefore, trend analysis was carried out for these locations. To exclude the data sets which did not pass from the tests was important to reach more accurate trend analysis of the data in hand. Results of the trend analysis showed that the change of SD over the 41 years are in agreement with the globally identified surface solar radiation dimming and brightening time periods all over the world. The dimming period is mainly between the years 1970 and about 1990 while the brightening period is from about 1990 to 2010. The yearly averages of SD data sets of 27 locations out of 36, for the years in the dimming period, were in a good agreement with the global dimming trends. However, for the brightening period the agreement was not as clear as it was in the dimming period. Nevertheless, during the brightening period, the data set of most of the locations had zero trends or noticeably reduced rates of decrease of SD. The dimming might be attributed to the increase in air pollution and this might be an indication of human induced climate change. Larger amounts of negative trends during winter months supported this conclusion. However, to reach a concrete conclusion more accurate of different climatic parameters should be analyzed. Satellites images may be helpful for further clarifications of such conclusions on climate change issues.

(None) Technical Summary of Thesis: The topic of my thesis is currency crisis. Currency crises have been a recurrent feature of the international economy from the invention of paper money. They are not confined to particular economies or specific region. They take place in developed, emerging, and developing countries and are spread all over the globe. Countries that experience currency crises face economic losses that can be huge and disruptive. However, the exacted toll is not only financial and economic, but also human, social, and political. It is clear that the currency crisis is a real threat to financial stability and economic prosperity. The main objective of this thesis is to analyze the determinants of currency crises for twenty OECD countries and South Africa from 1970 through 1998. It systematically examines the role of economic fundamentals and contagion in the origins of currency crises and empirically attempts to identify the channels through which the crises are being transmitted. It also examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. The first chapter identifies the episodes of currency crisis in our data set. Determining true crisis periods is a vital step in the empirical studies and has direct impact on the reliability of their estimations and the relevant policy implications. We define a period as a crisis episode when the Exchange Market Pressure (EMP) index, which consists of changes in exchange rates, reserves, and interest rates, exceeds a threshold. In order to minimize the concerns regarding the accuracy of identified crisis episodes, we apply extreme value theory, which is a more objective approach compared to other methods. In this chapter, we also select the reference country, which a country’s currency pressure index should be built around, in a more systematic way rather than by arbitrary choice or descriptive reasoning. The second chapter studies the probability of a currency exiting a tranquil state into a crisis state. There is an extensive literature on currency crises that empirically evaluate the roots and causes of the crises. Despite the interesting results of the current empirical literature, only very few of them account for the influence of time on the probability of crises. We use duration models that rigorously incorporate the time factor into the likelihood functions and allow us to investigate how the amount of time that a currency has already spent in the tranquil state affects the stability of a currency. Our findings show that high values of volatility of unemployment rates, inflation rates, contagion factors (which mostly work through trade channels), unemployment rates, real effective exchange rate, trade openness, and size of economy increases the hazard of a crisis. We make use of several robustness checks, including running our models on two different crisis episodes sets that are identified based on monthly and quarterly type spells. The third chapter examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. As in our previous paper, duration analysis is our methodology to study the probability of a currency crisis occurrence under different exchange rate regimes and capital mobility policies. The third chapter finds that there is a significant link between the choice of exchange rate regime and the incidence of currency crises in our sample. Nevertheless, the results are sensitive to the choice of the de facto exchange rate system. Moreover, in our sample, capital control policies appear to be helpful in preventing low duration currency crises. The results are robust to a wide variety of sample and models checks.

With the extant work on civil war duration as a starting point, this project uses the Ugandan case to identify and address theoretical aporias in our existing understanding of the determinants of duration. The vast majority of existing work begins with the assumption that the rebel force is the determining factor in the duration of conflict. Challenging this assumption, I argue that civil war duration should be understood as a function of the calculations made by both the rebel units and the established state, a dynamic that has implications for the way in which we think of the preferences of the state. Finally, that incentive structures exist, given the nature of post-colonial states that lower the utility of peace for elected leadership and reduce their willingness to provide peace as a collective good to the broader population as civil war can be used as one of Jeffrey Herbst’s buffer mechanisms.

Geographic space is an important friction preventing the instantaneous matching of unemployed workers to job vacancies. Cities reduce spatial frictions by decreasing the average distance between potential match partners. Owing to these search efficiencies, theories of agglomeration predict that unemployed workers in larger labor markets find employment faster than observationally similar workers in smaller markets. Existing studies rely on cross-sectional variation in aggregate unemployment rates across spatially distinct labor markets to test for scale effects in job search. A major difficulty with these studies is that the unemployment rate is, at any given time, simultaneously the incidence and duration of unemployment. Therefore, conclusions about unemployment exits using the unemployment rate are confounded by transitions into unemployment. This dissertation examines the relationship between market scale unemployment duration for permanently laid off workers in the U.S. Using a large sample of individual unemployment spells in 259 MSAs, proportional hazard model estimates predict a negative relationship between market scale and the hazard of exiting unemployment. This effect is strengthened when space is explicitly controlled for and measured with greater precision. These results are consistent with the hypothesis that search efficiencies lead workers to increase their reservation wages. 2SLS estimates show that re-employment earnings for permanently laid off workers increase with market scale after controlling for endogenous search duration. These effects are robust to standard controls, as well as controls for local labor market conditions. These results challenge the view that search efficiencies lead to lower unemployment rates through faster job-finding rates.

Reading is a fundamental skill for functioning in today’s society. Given the breadth of activities that require reading, it is important to develop a comprehensive model of basic reading processes. Furthermore, considering that many pictures co-appear with words in everyday life, it is imperative to understand the nature of picture identification processes, as well as how they interact with reading processes. As such, the present thesis focuses on developing a model of reading and extending it to include picture processing. In the present research, experiments on word identification (Experiments 1 and 2) examined onset reaction time (RT) in a word naming task using an additive factors method. The pattern of additive and overadditive joint effects on naming RT among Instructions (INST: name all, name words), Word Frequency (WF: log10HAL), Semantic Neighbourhood Density (SND: Inverse Ncount), and Word Type (WT: regular, exception) supported a cognitive chronometric architecture consisting of at least two cascaded stages of processing, with the orthographic lexical system as the locus of the INST x WF and the INST x SND interactions, and the phonological output system as the locus of the WF x WT and the SND x WT interactions. Additivity between INST and WT supports the notion that these variables affect separable systems, and a WF x SND interaction supports a common locus of their effects. These results support a dual-route cascaded model over parallel processing models of basic reading. We also examined response duration (RD) in these data by recording and hand-marking vocal responses, which provides evidence that reading processes are ongoing even after the initiation of a vocal response, and supports the notion that the more lexically a word is read, the shorter the RD. As such, the effects of WT and INST on RD were opposite to their effects on RT. Given the dissociating effects between RT and RD, these results provide new challenges to all models of basic reading processes. Experiments on picture and word identification (Experiments 3 and 4) involved localizing common systems and connections between these processes, and served to extend the dual-route model of reading. These experiments examined naming RT and RD for exception and regular words, and their corresponding pictures. The pattern of joint effects on RT among Format (pictures, words), Picture-Orthography Agreement, WF, and WT (regular, exception) supported a triple-route cascaded model. The results suggest the orthographic lexical system is accessed for both picture and word naming, and demonstrated a dissociation between regular and exception words on RT versus RD, whereas pictures consistently yielded an exception item advantage for both measures. Experiment 4 examined Arabic digits and their corresponding number words, and found that Arabic digits produce shorter RDs than number words. In general, the results suggest that the picture and word identification systems are strongly coupled between the picture memory system and the orthographic lexical system, particularly for items that rely on “whole-word” lexical representations. We argue that RD provides a wider window for exploring cognition, and a converging measure of lexical processing, which must be considered when studying basic identification processes of any stimulus type. The development of a comprehensive model of basic reading processes will help identify behavioural markers of normal reading processes, and will serve to advance research on basic word recognition. In addition, given that a broad definition of ‘literacy’ should include picture processing, the development of a model that includes picture processing will serve to advance research on how reading and picture processing interact with each other, which may be critical for individuals with low literacy skills.

In the last decade, 802.11 wireless devices data-rates have increased by three orders of magnitude, while communications experiencing low throughput are still largely present. Such throughput loss is a fundamental problem of wireless networking that is difficult to diagnose and amend. My research addresses two key causes of throughput loss: MAC layer protocol overhead and destructive link interference. First, I design WiFi-Nano reducing the channel access overhead by an order of magnitude leveraging an innovative speculative technique to transmit preambles. This new concept is based on simultaneous preamble transmission and detection via a self-interference cancellation design, and paves the way to the realization of the collision detection paradigm in wireless networks. Next, I propose 802.11ec (Encoded Control), the first 802.11-based protocol that eliminates the overhead of control packets. Instead, 802.11ec coordinates node transmissions via a set of predefined pseudo-noise codewords, resulting in the dramatic increase of throughput and communication robustness. Finally, I design MIDAS, a model-driven network management tool that alleviates low throughput wireless links identifying key corrective actions. MIDAS' key contribution is to reveal the fundamental role of node transmission coordination in characterizing destructive interference. I implement WiFi-Nano, 802.11ec, and MIDAS using a combination of WARP FPGA-based radio boards, custom emulation platforms, and network simulators. The results obtained show that WiFi-Nano increases the network throughput by up to 100%, 802.11ec improves network access fairness by up to 90%, and MIDAS identifies corrective actions with a prediction error as low as 20%.

¡§Intergenerational (IG) appeal¡¨ is an ad focusing on the relationship between parents and children in order to enhance heritage image of a brand and facilitate the likelihood that parents introduce the brand to their sons and daughters. This study examines the application of IG appeal on advertising. An experimental study is conducted to examine the moderating effects of brand duration and (in)congruent brand-gender extension on the effect of IG appeal. The experiment in a 4 advertising appeal (IG appeal: male vs. female, non-IG appeal: male vs. female) x 2 brand duration (long vs. short) x 2 brand-gender extension (congruent vs. incongruent) factorial design is developed. A series of analysis of variance (ANOVA) are used to test the proposed hypotheses. Results of the experiment indicate that brand duration facilitates the effects of IG appeal. In addition, congruent brand extension increases the effects of IG appeal. More importantly, a three-way interaction is observed. In incongruent brand-gender extension, IG appeals used to present brands with short brand duration are more effective than Non-IG appeal. These findings should be incorporated into heritage branding when media campaign is developed to increase branding influences.

The purpose of the present study was to examine the effects of positive and negative symptoms, and duration of illness on emotion processes / ability to understand emotion related cues, experience of emotion, and expression of emotion. A total of 46 schizophrenia patients from Ankara Oncology Hospital Psychiatry Clinic / 23 of them were diagnosed with schizophrenia for at least 10 years, and 23 of them were diagnosed for less than 10 years, participated in the study. Besides, a total of 23 non-clinical subjects / which were similar to the clinical group in terms of educational information, participated to the study. A video-clip which consists of scenes that elicited four types of emotions (fear, disgust, sadness, happiness) was presented to the participants. Understanding of emotion related cues and the experienced emotion were rated through self-report. Facial expressions of the participants were rated through their recorded faces by three psychologists, who were specifically trained for emotional facial expression rating. Symptomatology was assessed by Positive and Negative Symptom Scale (PANSS), and Calgary Depression Scale for schizophrenia patients. Presence of any psychopathology of healthy group was measured through Brief Symptom Inventory. Multivariate Analysis of Variance (MANOVA) revealed that chronic patients presented more understanding of context impairments than acute patients and non-clinical group. In addition to these findings, positive symptoms assessed by PANSS were found to be positively correlated with the understanding context impairment. Therefore, It was suggested that positive symptoms, such as hallucinations and delusions interfere with understanding context task. The results were discussed in the light of the literature and clinical and research implications of the study presented. Finally, necessity of using neurological, biological and cognitive assessment methods for further studies was suggested in order to understand deficits in emotional processes.

Estimation of construction durations is a very crucial part of project planning, as several key decisions are based on the estimated durations. In general, construction durations are estimated by using planning and scheduling techniques such as Gannt or bar chart, the Critical Path Method (CPM), and the Program Evaluation and Review Technique (PERT). However, these techniques usually require detailed design information for estimation of activity durations and determination of the sequencing of the activities. In some cases, pre-design duration estimates may be performed by using these techniques, however, accuracy of these estimates mainly depends on the experience of the planning engineer. In this study, it is aimed to develop and compare alternative methods for conceptual duration estimation of building constructions with basic data information available at the early stages of projects. Five parametric duration estimation models are developed with the data of 17 building projects which were constructed by a contractor in United States. Regression analysis and artificial neural networks are used in the development of these five duration estimation models. A parametric cost estimation model is developed using regression analysis for cost estimations to be used in calculating the prediction performances of cost based duration estimation models. Finally, prediction performances of all parametric duration estimation models are determined and compared. The models provided reasonably accurate estimates for construction durations. The results also indicated that construction durations can be predicted accurately without making an estimate for the project cost.

Reference models developed for software process improvement (SPI) provide guidelines about what to do while assessing and improving the processes, but they do not answer the questions of how. There have been a number of studies that try to find effective and strategic implementation models or to identify factors that affect the SPI success. However, these studies do not provide answers to questions about the effect of these factors on SPI program duration or accelerated SPI studies. This study aims to investigate the factors that affect CMMI-based SPI duration. It consists of two phases: in the first phase, factors that influence SPI success are identified and hypotheses related to these factors are formulated based on the case studies published in the literature. In the second phase of the study, hypotheses are revised based on the results of the qualitative research conducted in seven companies, six of which have obtained CMMI-Level 3 certification as a consequence of their SPI effort. The study has shown that management commitment and involvement as well as process documentation have had a significant shortening effect on CMMI-based SPI duration, within the context of the studied cases. Software process improvement / CMMI / Success factors / Duration factors. Enter specific words or phrases that are listed in thesis.