The COVID-19 pandemic, which first spread to the People of Republic of China and then to other countries in a short time, affected the whole world by infecting millions of people and have been increasing its impact day by day. Hundreds of researchers in many countries are in search of a solution to end up this pandemic. This study aims to contribute to the literature by performing detailed analyses via a new three-staged framework constructed based on data envelopment analysis and machine learning algorithms to assess the performances of 142 countries against the COVID-19 outbreak. Particularly, clustering analyses were made using k-means and hierarchic clustering methods. Subsequently, efficiency analysis of countries were performed by a novel model, the weighted stochastic imprecise data envelopment analysis. Finally, parameters were analyzed with decision tree and random forest algorithms. Results have been analyzed in detail, and the classification of countries are determined by providing the most influential parameters. The analysis showed that the optimum number of clusters for 142 countries is three. In addition, while 20 countries out of 142 countries were fully effective, 36% of them were found to be effective at a rate of 90%. Finally, it has been observed that the data such as GDP, smoking rates, and the rate of diabetes patients do not affect the effectiveness level of the countries.

As of 21 th century, the terms of efficiency and productivity have become notions which dwells on both business and academic world more frequently compared to past. It is known that it is hard to increase the efficiency and productivity of both production and service systems. In this study, the efficiency analysis of the branches of a bank was conducted. Furthermore, a Weighted Stochastic Imprecise Data Envelopment Analysis (WSIDEA), which is a new approach developed based on Data Envelopment Analysis (DEA), was proposed. Efficiency levels and results of decision-making units were examined according to the proposed new method. Additionally, six different DEA model results are obtained. The results of the six different DEA model and the proposed "WSIDEA" model were compared in terms of efficiency level of decision-making units, and the differences between them were examined. Sensitivity of the inefficient units were also examined. On the other hand, unrealistic efficiency levels created by traditional methods for branches were also analyzed. Apart from all these sensitivity analyses, the sensitivity of the data set used in the analysis is scrutinized.

Objective: Many individuals with cigarette addiction are known for beginning to smoke cigarettes during adolescence years. In this study, we aimed to present the clinical outcomes of smoking cessation project conducted in an Anatolian school in Kartal district of Istanbul, Turkey. Methods: Social and motivational studies were carried out on adolescent smokers after scanning in terms of smoking in an Anatolian school and 44 of these adolescents who are clinical requirements were evaluated and followed by Chest disease and child and adolescent mental health for six months. Carbonmonoxide (CO) measurements in the expiratory air and carboximeter (piCO smokerlyzer, Bedfont Scientific Ltd, England) were made at the first visit and follow-up. Simultaneously, K-SADS PL (Schedule for Schizophrenia and Affective disorders for School Age Children) was administered diagnostically in mental health evaluation. Results: A total of 44 adolescents, 13 girl (29.5%) and 31 boy (70.5%), with a mean age of 17.31 were followed up. The mean age of initiation of cigarette smoking was 14.2 ± 1 and 32 (82.7%) adolescent were found to have at least one smoker in their home. While 22.7% of adolescents did not try smoking cessation, 77.3% of them did. Six of these adolescents indicated that they did not smoke during the six months; 55.5% of these adolescents have at least one mental illness; the most common diagnoses were 25.0% (n = 11) of ADHD (Attention Deficit Hyperactivity Disorder) and 20% (10) of MD (Major Depression). While depression was significantly frequent in girls (p = 0.043), the frequency of ADHD was not significant in terms of gender. Depression presence was associated with early onset of cigarette smoking in males (p = 0.019), but not with females (p = 0.394). There was a statistically significant correlation between smoking cessation effort and age in the follow-up period (p = 0.022), and earlier adolescents stated that they wanted to quit smoking more. While there is no significant association between smoking cessation effort and mental disease, there was a statistically close relation with parent and sibling smoking (p = 0.07) and significant correlation with motivation and smoking cessation effort (p = 0.016). Conclusions: Smoking cessation work in adolescents is much more difficult than in adults. Biological and social factors and peer impact influence interventions. In our study, very few adolescents stated to quit smoking for 6 months, and the rate of psychiatric illnesses among adolescents and the presence of individuals smoking at home were found to be quite high. It has been the result of these factors also affecting the success of adolescents to start smoking and to quit smoking.

Öz 21. yüzyılda gelişmiş ve gelişmekte olan ülkelerin en önemli problemlerinden birisi de trafik problemidir. Birçok ülkede trafik probleminin çözümüne yönelik planlamalar, faaliyetler ve bu soruna ilişkin harcanan zaman ve bütçeler her geçen gün artırılmaktadır. Bununla beraber literatüre bakıldığında küme örtme ve p-medyan modelleri ile yapılmış birçok çalışmaya rastlanmaktadır. Paralel olarak ulaşım üzerine yapılan çalışmalar da literatürde sıklıkla yer almaktadır. Ancak küme örtme ve alternatif servis seviyeli p-medyan modelleri ile raylı sistem üzerine yapılmış çalışmalar diğer alanlara kıyasla daha sınırlı ve az sayıdadır. Bu sebeple bu çalışmada Kocaeli ili sınırları içerisinde yer alan Gebze ve Darıca ilçelerinde yapılması planlanan metro projesi bağlamında, güzergâh üzerinde yapılacak metro hattının optimum istasyon sayısının ve istasyonların lokasyonunun belirlenmesi problemine küme kapsama ve alternatif servis seviyeli p-medyan modelleri ile çözüm aranmıştır. Sonuçlar detaylıca analiz edilmiştir.