DATA REPLICATION IN DISTRIBUTED SYSTEMS USING OLYMPIAD OPTIMIZATION ALGORITHM

Achieving timely access to data objects is a major challenge in big distributed systems like the Internet of Things (IoT) platforms. Therefore, minimizing the data read and write operation time in distributed systems has elevated to a higher priority for system designers and mechanical engineers. Replication and the appropriate placement of the replicas on the most accessible data servers is a problem of NP-complete optimization. The key objectives of the current study are minimizing the data access time, reducing the quantity of replicas, and improving the data availability. The current paper employs the Olympiad Optimization Algorithm (OOA) as a novel population-based and discrete heuristic algorithm to solve the replica placement problem which is also applicable to other fields such as mechanical and computer engineering design problems. This discrete algorithm was inspired by the learning process of student groups who are preparing for the Olympiad exams. The proposed algorithm, which is divide-and-conquer-based with local and global search strategies, was used in solving the replica placement problem in a standard simulated distributed system. The 'European Union Database' (EUData) was employed to evaluate the proposed algorithm, which contains 28 nodes as servers and a network architecture in the format of a complete graph. It was revealed that the proposed technique reduces data access time by 39% with around six replicas, which is vastly superior to the earlier methods. Moreover, the standard deviation of the results of the algorithm's different executions is approximately 0.0062, which is lower than the other techniques' standard deviation within the same experiments

Historic Reinforced Concrete in Alberta: Analysis and Conservation of Two Structures

The Brooks Aqueduct and the Greenhill mine tipple structure were built in the turn of the twentieth century in southern Alberta. They were among the first reinforced concrete structures to be built in that region and are considered great engineering and construction achievements for their time. They were both built at a time when there was no standard for the design of reinforced concrete structures in North America and lots of issues about the concrete design and construction, especially from the durability point of view, were still unknown. Both structures had a great impact on the economy of their local regions and now are designated as national and provincial historic sites respectively. Frequent repair and maintenance became necessary from the early stages of operation of Brooks Aqueduct due to design and construction deficiencies. Both structures show significant signs of damage and deterioration and need to be evaluated and properly repaired and maintained. This research involves evaluation of the two structures through site inspections and laboratory tests on the samples taken from them. The work also involves numerical modelling of the structures to identify areas of possible over stress and find the main causes of damage and deterioration. Several similarities and differences are found between the concrete used in these structures and their deterioration mechanism. The main goal in evaluation and repair of Brooks Aqueduct is to maintain it as a monument and an engineering and construction achievement. In the case of the Greenhill mine tipple structure, two scenarios were studied: adaptive reuse as a restaurant and maintaining the structure as a monument. Results of the analyses show that although there was clear lack of understanding about the behaviour of concrete in the design of these structures, most of the damage and deterioration are non-structural and has happened due to durability issues mainly from exposure to freeze-thaw cycles and corrosion of the reinforcement. Service life analysis of the two structure is also performed based on theoretical models and test results. Recommendations for extending the remaining service life and conservation and retrofitting of the two structures and similar cases are provided based on the results of the tests and analyses. The research identifies common types of problems in historic reinforced concrete structures constructed in Alberta in the early twentieth century and ways to recognise and overcome these problems. The results also emphasize that in evaluation of concrete from the early twentieth century, one has to look for certain problems such as lack of resistance against durability issues (mainly freeze-thaw and carbonation), lack of precision in placement of the reinforcing steel (rebar), lack of rebar splice lengths, lack of proper cover of concrete and lack of proper grading and selection of aggregates

Comparing the effectiveness of acceptance and commitment therapy and dialectical behavioral therapy on coherent self knowledge, emotional regulation and life quality of hemodialysis patients

Introduction: Chronic kidney diseases are one of the problems that threaten people's physical and psychological health. Aim: The present study aims to compare the effectiveness of acceptance and commitment therapy and dialectical behavioral therapy on coherent self-knowledge, emotional regulation and life quality of hemodialysis patients. Method: The present study is a semi-experimental one with a pre-test, post-test and a control group design. The statistical population of this research was hemodialysis patients of Shafa Hospital and Javad Al-Aima Clinic in Kerman in 2022. For this research 45 hemodialysis patients were selected using convenience sampling and randomly placed into two experimental groups of effectiveness of acceptance and commitment therapy and dialectical behavioral therapy and a control group. The research tools included Qorbani Coherent Self-knowledge (2008), Gross Emotional Regulation (2003) and World Health Organization Life Quality (1996) Questionnaire. The collected data were analyzed using covariance analysis or ANACOVA statistical exams, Tukey's b post Hoc exam using SPSS-24 statistical software. Results: The result of covariance analysis showed significance difference between the experimental and control groups as (P<0.001). Compare to the control group, improvements were observed in coherent self-knowledge, emotional regulation and life quality of hemodialysis patients participated in both experimental groups. Conclusion: Acceptance and commitment therapy and dialectical behavioral therapy, are proper methods in increasing coherent self-knowledge, emotional regulation and life quality of hemodialysis patients. It is recommended that these approaches can be used alongside other medical treatments

High-sensitivity in various gyrator-based circuits with exceptional points of degeneracy

Exceptional points of degeneracy (EPD) can enhance the sensitivity of circuits by orders of magnitude. We show various configurations of coupled LC resonators via a gyrator that support EPDs of second and third-order. Each resonator includes a capacitor and inductor with a positive or negative value, and the corresponding EPD frequency could be real or imaginary. When a perturbation occurs in the second-order EPD gyrator-based circuit, we show that there are two real-valued frequencies shifted from the EPD one, following a square root law. This is contrary to what happens in a Parity-Time (PT) symmetric circuits where the two perturbed resonances are complex valued. We show how to get a stable EPD by coupling two unstable resonators, how to get an unstable EPD with an imaginary frequency, and how to get an EPD with a real frequency using an asymmetric gyrator. The relevant Puiseux fractional power series expansion shows the EPD occurrence and the circuit's sensitivity to perturbations. Our findings pave the way for new types of high-sensitive devices that can be used to sense physical, chemical, or biological changes

How to achieve exceptional points in coupled resonators using a gyrator or PT-symmetry, and in a time-modulated single resonator: high sensitivity to perturbations

We study the rise of exceptional points of degeneracy (EPD) in various distinct circuit configurations such as gyrator-based coupled resonators, coupled resonators with PT-symmetry, and in a single resonator with a time-varying component. In particular, we analyze their high sensitivity to changes in resistance, capacitance, and inductance and show the high sensitivity of the resonance frequency to perturbations. We also investigate stability and instability conditions for these configurations; for example, the effect of losses in the gyrator-based circuit leads to instability, and it may break the symmetry in the PT-symmetry-based circuit, also resulting in instabilities. Instability in the PT-symmetry circuit is also generated by breaking PT-symmetry when one element (e.g., a capacitor) is perturbed due to sensing. We have turned this instability “inconvenience” to an advantage, and we investigate the effect of nonlinear gain in the PT-symmetry coupled-resonator circuit and how this leads to an oscillator with oscillation frequency very sensitive to perturbation. The circuits studied in this paper have the potential to lead the way for a more efficient generation of high-sensitivity sensors that can detect very small changes in chemical, biological, or physical quantities

Optimal Design of Air Quality Monitoring Network and its Application in an Oil Refinery Plant: An Approach to Keep Health Satus of Workers

Background: Industrial air pollution is a growing challenge to humane health, especially in developing countries, where there is no systematic monitoring of air pollution. Given the importance of the availabil­ity of valid information on population exposure to air pollutants, it is important to design an optimal Air Quality Monitoring Network (AQMN) for assessing population exposure to air pollution and predicting the magnitude of the health risks to the population. Methods: A multi-pollutant method (implemented as a MATLAB program) was explored for configur­ing an AQMN to detect the highest level of pollution around an oil refinery plant. The method ranks potential monitoring sites (grids) according to their ability to represent the ambient concentra­tion. The term of cluster of contiguous grids that exceed a threshold value was used to calculate the Station Dosage. Selection of the best configuration of AQMN was done based on the ratio of a sta­tion’s dosage to the total dosage in the network. Results: Six monitoring stations were needed to detect the pollutants concentrations around the study area for estimating the level and distribution of exposure in the population with total network effi­ciency of about 99%. An analysis of the design procedure showed that wind regimes have greatest effect on the location of monitoring stations. Conclusion: The optimal AQMN enables authorities to implement an effective program of air quality management for protecting human health

Mushroom Poisoning in the Southwest Region of the Caspian Sea, Iran: A Retrospective Study

Background: Mushroom poisoning as a medical emergency can be a challengingproblem for physicians. Despite the vast resources of poisonous mushrooms inIran, few studies have been done in this regard, especially in the southwest regionof the Caspian Sea that is very suitable for mushroom growth. Therefore, the aimof this study was to evaluate our experience with mushroom poisoning in thisregion.Methods: This retrospective study reviewed the records of 102 patients who wereadmitted to the Emergency Department of Razi Hospital of Rasht, the only referraldepartment in this region, from May 2006 to May 2011. Data were analyzed byChi-square test, ANOVA, and student’s t-test.Results: The patients’ age ranged from 13 to 75 years and 47 of them were maleand the rest 55 were female. Overall, 57.8% of mushroom poisoning casesoccurred in patients from urban areas. Most incidences were reported betweenSeptember and October, the rainy season in Guilan. Except for four patients withtachycardia, others had stable vital signs. The most frequent symptoms (86.4%)were nausea and vomiting. Complete blood cell count revealed that 28.4% of thepatients had leukocytosis but all of them had platelet counts of less than 100000.Conclusions: This study showed that all cases had mild to moderate symptomsthat were treated by simple supportive therapies. This suggested that mushroomspecies in our region are less dangerous but further studies need to establish whattoxins and species are responsible for mushroom toxicity