Searches for Fast Radio Bursts

Following the discovery of fast radio bursts (FRBs) in 2007, astronomers have entered a new era in astronomy in which understanding the nature of these type of radio transients is one of the most important modern astronomy questions. In this thesis I detail our current state of knowledge in this rapidly evolving field and describe real-time search systems designed to find FRBs using the 20-meter radio telescope at the Green Bank Observatory and the Arecibo L-band Feed Array (ALFA) receiver of the Arecibo 300-meter telescope in Puerto Rico. These experiments are called GBTrans and ALFABURST, respectively. I give details of the observing systems and report on the non-detection of FRBs for both surveys. GBTrans is sensitive enough to detect approximately half of all currently known FRBs while ALFABURST is sensitive enough to detect almost all of the current FRB population. I estimate that GBTrans survey probed redshifts out to about 0.3 corresponding to an effective survey volume of around 124,000 Mpc3. Assuming a constant density for sources per unit co-moving volume and considering the possibility of detecting bright FRBs in the sidelobes of the ALFA beams, I estimate ALFABURST probed redshifts out to about 3.5. Based on this, the expected event rate would be at most two FRBs per year at the 99% confidence level. Modeling the FRB rate as a function of fluence, F, as a power law with Fα, I constrain the index α \u3c 2.5 at the 90% confidence level based on the GBTrans results. A number of pulses from previously known pulsars were detected in both the GBTrans and ALFABURST surveys which provided excellent verification on the survey sensitivity used to compute the effective volumes quoted above. One Galactic transient, J1845+00, was found in the ALFABURST survey. This is most likely a member of the rotating radio transient (RRAT) population. It has so far not been seen in follow-up observations. Eight further single-pulse candidates from ALFABURST are also reported. At the time of writing, due to incomplete metadata records, the positions of these sources are not well enough known to allow further follow-up. Future observations with ALFABURST are anticipated in the coming year. Finally, I also describe preliminary observations from an Arecibo survey of gamma-ray burst sources

Complex dynamic behaviors of the complex Lorenz system

AbstractThis study compares the dynamic behaviors of the Lorenz system with complex variables to that of the standard Lorenz system involving real variables. Different methodologies, including the Lyapunov Exponents spectrum, the bifurcation diagram, the first return map to the Poincaré section and topological entropy, were used to investigate and compare the behaviors of these two systems. The results show that expressing the Lorenz system in terms of complex variables leads to more distinguished behaviors, which could not be achieved in the Lorenz system with real variables, such as quasi-periodic and hyper-chaotic behaviors

A Reinforcement Learning Based Model for Adaptive ServiceQuality Management in E-Commerce Websites

Providing high-quality service to all users is adifficult and inefficient strategy for e-commerce providers,especially when Web servers experience overload condi-tions that cause increased response time and requestrejections, leading to user frustration and reduced revenue.In an e-commerce system, customer Web sessions havediffering values for service providers. These tend to: givepreference to customer Web sessions that are likely tobring more profit by providing better service quality. Thispaper proposes a reinforcement-learning based adaptivee-commerce system model that adapts the service qualitylevel for different Web sessions within the customer’snavigation in order to maximize total profit. The e-com-merce system is considered as an electronic supply chainwhich includes a network of basic e- providers used tosupply e-commerce services for end customers. The learneragent noted as e-commerce supply chain manager(ECSCM) agent allocates a service quality level to thecustomer’s request based on his/her navigation pattern inthe e-commerce Website and selects an optimized combi-nation of service providers to respond to the customer’srequest. To evaluate the proposed model, a multi agentframework composed of three agent types, the ECSCMagent, customer agent (buyer/browser) and service provideragent, is employed. Experimental results show that theproposed model improves total profits through costreduction and revenue enhancement simultaneously andencourages customers to purchase from the Websitethrough service quality adaptation

A Robust Adaptive Workload Orchestration in Pure Edge Computing

Pure Edge computing (PEC) aims to bring cloud applications and services to the edge of the network to support the growing user demand for time-sensitive applications and data-driven computing. However, mobility and limited computational capacity of edge devices pose challenges in supporting some urgent and computationally intensive tasks with strict response time demands. If the execution results of these tasks exceed the deadline, they become worthless and can cause severe safety issues. Therefore, it is essential to ensure that edge nodes complete as many latency-sensitive tasks as possible. \\In this paper, we propose a Robust Adaptive Workload Orchestration (R-AdWOrch) model to minimize deadline misses and data loss by using priority definition and a reallocation strategy. The results show that R-AdWOrch can minimize deadline misses of urgent tasks while minimizing the data loss of lower priority tasks under all conditions.Comment: 9 pages, Accepted in ICAART conferenc

Age- and sex-related variations in the brain white matter fractal dimension throughout adulthood: an MRI study.

To observe age- and sex-related differences in the complexity of the global and hemispheric white matter (WM) throughout adulthood by means of fractal dimension (FD)

The study of validity and reliability of formetric 4D system in measuring of deformites in kyphosis and lordosis in women

زمینه و هدف: یکی از مسائل مهم در حیطه حرکات اصلاحی، اندازه گیری قوس های ستون فقرات به ویژه کیفوز و لوردوز است، یکی از این ابزارها، دستگاه ارزیاب فورمتریک 4 بعدی است که وسیله ای دقیق و بدون خطر اشعه می باشد. هدف از این پژوهش توصیفی، بررسی میزان روایی و پایایی دستگاه ارزیاب ستون فقرات در اندازه گیری ناهنجاری های کیفوز و لوردوز می باشد. روش بررسی: در این پژوهش که جامعه آماری آن را کلیه بیماران مراجعه کننده به متخصصان ارتوپد و مغز و اعصاب شهرستان اراک تشکیل می دادند 27 نفر خانم به روش در دسترس به عنوان نمونه انتخاب شدند. از ضریب همبستگی درون طبقه ای درون گروهی (Intraclass correlation coefficient=ICC) برای بررسی پایایی درونگرای دستگاه و برای تعیین روایی دستگاه از ضریب همبستگی پیرسون استفاده گردید. تمامی تجزیه و تحلیل‌های آماری توسط نرم افزار SPSS و در سطح معنی‌داری 05/0 α= مورد بررسی قرار گرفت. یافته ها: نتایج نشان داد که روایی دستگاه ارزیاب در اندازه گیری زوایای کیفوز ICT-ITL، VP–ITL، VP– T12 در مقایسه با رادیوگرافی به ترتیب همبستگی ای برابر با 712/0، 771/0 و 745/0 (05/0>P) و پایایی درونگرای بدست آمده (ICC) برابر با 966/0، 947/0 و 887/0 (001/0>P) بوده است. همچنین بررسی روایی دستگاه ارزیاب در اندازه گیری زوایای لوردوز ITL-ILS، ITL-DM، T12-DM در مقایسه با رادیوگرافی، میزان همبستگی به ترتیب 713/0، 734/0 و 458/0 (05/0>P) و پایایی درونگرای دستگاه (ICC)، 923/0، 884/0، 896/0 (001/0>P) بوده است. نتیجه گیری: بر اساس نتایج این مطالعه، دستگاه فورمتریک در اندازه گیری عارضه های کیفوز و لوردوز، روایی و پایایی درونگرای خوبی دارد، از این رو می‌توان گفت دستگاه ارزیاب برای اندازه گیری این ناهنجاری ها، ابزاری روا و پایا است و جایگزینی مناسب برای رادیوگرافی می باشد

Effectiveness of Group Counselling on Improvement of Marital Relationship in Infidelity-Affected Mothers of Students in Tehran City

 Disclosure of infidelity may have destructive effects both on couples and children. Given the fact that children’s physical and psychological health depends on their parents’ healthy mutual relationship, attending improvement of couples’ relationships after infidelity disclosure seems necessary. The present study aimed to determine effectiveness of group counselling on improvement of marital relationship in infidelity-affected mothers. This applied study used quasi-experimental design with pre-posttest approach. Of the study population comprising all infidelity-affected mothers of students in Tehran city who had referred to counselling centers of Department of Education, 16 mothers were selected and randomly divided into the experimental and control groups.  Vaughan’s Spouse Infidelity Questionnaire and scholar-made Improvement of Marital Relations Questionnaire were used. The experimental group received 20 sessions of group counselling twice weekly. Data were analyzed via covariance and multivariable variance analysis. The results confirmed positive effects of group counselling on improvement of marital relationships (F = 11/10, p<. 0.05 ) and verbal communication skills (F=12.188, P<0.05) in infidelity-affected mothers, but it was not effective for enhancing security feeling of students growing up in these families (F=1. 139, p<0.05)