Proactive controller assignment schemes in SDN for fast recovery

​© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A sizeable software defined network with a single controller responsible for all forwarding elements is potentially failure-prone and inadequate for dynamic network loads. To this end, having multiple controllers improves resilience and distributes network control overhead. However, when there is a disruption in the control plane, a rapid and performant controller-switch assignment is critical, which is a challenging technical question. In this work, we propose a proactive switch assignment approach in case of controller failures using a genetic algorithm based heuristic that considers controller load distribution, reassignment cost and probability of failure. Moreover, we compare the performance of our scheme with random and greedy algorithms. Experiment results show that our proposed PREFCP framework has better performance in terms of probability of failure and controller load distributio

THE COMPARISON OF ATTENTION LEVELS OF UNIVERSITY STUDENTS IN DIFFERENT SPORT BRANCHES

In this study, it was desired to measure the attention levels of university students in different branches and reveal the severity, direction of the relationship between sportspeople in different branches of sport and sedentary and also the effect of sport on attention. The population of the research is composed of 942 students between the ages of 17-28 who studied at the University of Firat in 2016-2017 academic year and are active in sport activities in 16 branches (Athletics, Basketball, Volleyball, Soccer, Futsal, Table Tennis, Tennis, Badminton, Boxing, Wrestling, Taekwon-do, Handball, Kickboxing, Folk Dance, Karate, and Marksmanship). The sample of the study consisted of 342 students selected by simple random sample method among 942 students (273 active students and 69 sedentary students). The d2 attention test was used to measure the attention levels of the students participating in the study and the obtained data were analyzed and evaluated by chi-square test, independent groups t-test and one- way analysis of variance (ANOVA) with the help of SPSS 22 statistical package program. In the study, it was observed that the students who play sports in the indoor fields have better attention skills than those who do sports in the outdoor fields when sport branches played in the indoor fields were compared with the ones played in outdoor fields.  Article visualizations

The comparative effects of esmolol and amiodarone on isolated coronary artery bypass grafts

Background/aim: Esmolol and amiodarone are two most commonly used antiarrhythmic drugs in coronary artery bypass grafting (CABG) surgery. Nevertheless, blockade of beta-2 receptors by increasing doses raise concerns about possible vasospasms. We studied the vasoactive effects of amiodarone and esmolol on left internal mammary artery (LIMA), radial artery (RA), and saphenous vein (SV) grafts. Materials and methods: After determining the presence of functional smooth muscle and endothelial layers, the responses of submaximally preconstricted graft samples were recorded in a tissue bath system. A total of 96 graft samples from 40 patients were used: 16 LIMA, 16 RA, and 16 SV grafts for each drug. Esmolol and amiodarone were added to reservoirs separately, starting from a concentration of 10-8 M until a concentration of 10-4 M. Results: Although both drugs caused vasodilatation, amiodarone exhibited a more potent vasodilatory effect than esmolol (P < 0.0001 for LIMA, P = 0.0128 for RA, and P < 0.0001 for SV). The vasodilatation rates with esmolol were 48.99 +/- 1. 2.28% in LIMA, 49.77 +/- 3.03% in RA, and 41.90 +/- 4.05% in SV grafts and with amiodarone they were 71.65 +/- 5.18% in LIMA, 58.61 +/- 5.87% in RA, and 65.07 +/- 4.09% in SV grafts. Conclusion: This in vitro study revealed that even increasing doses of both drugs induce vasodilatation of CABG grafts, with amiodarone having a more potent vasodilatory effect than esmolol

The Crisis and After: There Is No Alternative?

The present paper devises an account of the possibilities that the recent crisis opens up for capitalism, which dwells upon its history. The paper takes three propositions as its starting point: First, capitalism, which must solve the problem of coordination of the decisions of different agents in changing environment, is prone to periodic and structural crises because of its very institutional structure. Second, thus, crises should be seen as signs that indicate that economic and social institutional matrix is at fault, which requires new “solutions”. Third, an appropriate account of capitalism must also take into account that crises usually require transformation almost the entire economic and socio-political institutional structure of the system. Having said this, we try to address briefly to possible and likely transformation.Capitalism, Crisis, Institutional transformation

Monte Carlo Simulation of Boundary Crossing Probabilities with Applications to Finance and Statistics

This dissertation is cumulative and encompasses three self-contained research articles. These essays share one common theme: the probability that a given stochastic process crosses a certain boundary function, namely the boundary crossing probability, and the related financial and statistical applications. In the first paper, we propose a new Monte Carlo method to price a type of barrier option called the Parisian option by simulating the first and last hitting time of the barrier. This research work aims at filling the gap in the literature on pricing of Parisian options with general curved boundaries while providing accurate results compared to the other Monte Carlo techniques available in the literature. Some numerical examples are presented for illustration. The second paper proposes a Monte Carlo method for analyzing the sensitivity of boundary crossing probabilities of the Brownian motion to small changes of the boundary. Only for few boundaries the sensitivities can be computed in closed form. We propose an efficient Monte Carlo procedure for general boundaries and provide upper bounds for the bias and the simulation error. The third paper focuses on the inverse first-passage-times. The inverse first-passage-time problem deals with finding the boundary given the distribution of hitting times. Instead of a known distribution, we are given a sample of first hitting times and we propose and analyze estimators of the boundary. Firstly, we consider the empirical estimator and prove that it is strongly consistent and derive (an upper bound of) its asymptotic convergence rate. Secondly, we provide a Bayes estimator based on an approximate likelihood function. Monte Carlo experiments suggest that the empirical estimator is simple, computationally manageable and outperforms the alternative procedure considered in this paper

A communication and participation-oriented model proposal for current urban transformation processes

Research Problem: Urban transformation planning policies, which have been the focus during the last decade in Turkey, have begun to progress with renewal of risky areas with the introduction of Law No. 6306. While it was stated that increasing the quality of life and social rehabilitation of area residents were targeted in transformations where neighborhoods are transformed into urban land, in fact, resident expectations were not met and the residents, who experienced dissatisfaction in the transformed environments that were not suitable for their lifestyles, left these areas or continued their lives in despair due to economic reasons. Ignorance of resident expectations in transformation process reduces their quality of life and only through participation the residents, who are the actors that experience the impact of transformation the most, could express their preferred lifestyle. Aim: The present study aimed to propose a participatory transformation model in transforming the current transformation framework into a user-oriented approach. Method: In the development of the model, the participation scenarios / strategies were integrated into the break points in the process defined in Law No. 6306 which underlines the current urban transformation dynamics. Findings: Each experience that different transformation processes which the proposed model could be applied based on its own dynamics would create new structuring processes that would contribute to the model. Based on the model, it was aimed to establish continuous communication and information flow between users, architects, authorities and other stakeholders, to increase socio-physical satisfaction of the residents since the residence and residential environment would be built based on resident demands and to sustain the sense of belonging and satisfaction of the residents with the preferences. Conclusion: The process based on the proposals that were determined with participation principle and continuous communication between all stakeholders and especially the architect and residents would establish the foundation for not only to secure risky buildings, but also for socially and economically sustainable urban transformation projects that would provide added value to the city and improve the quality of life of urban residents