Optimum and Robust Design of Fibre-Reinforced Hybrid Composites with Manufacture Related Uncertainties

In this research, different methods are presented for design and multi-objective optimization of laminated hybrid composites when design variables are not deterministic due to manufacture related uncertainties. Since, flexural properties are more affected by hybridization of fibres, this research has focused on the design and optimization of laminated hybrid composites under flexural load. Robustness and hybrid effect are investigated with optimal and robust designs for carbon and glass fibre reinforced epoxy composites being presented

Design Optimization and Security For Communication Networks

In this work we introduce a new mathematical tool for optimization of routes, topology design, and energy efficiency in wireless sensor networks. We introduce a vector field formulation that models communication in the network, and routing is performed in the direction of this vector field at every location of the network. The magnitude of the vector field at every location represents the density of amount of data that is being transited through that location. We define the total communication cost in the network as the integral of a quadratic form of the vector field over the network area. With the above formulation, we introduce a mathematical machinery based on partial differential equations very similar to the Maxwell's equations in electrostatic theory. We show that in order to minimize the cost, the routes should be found based on the solution of these partial differential equations. In our formulation, the sensors are sources of information, and they are similar to the positive charges in electrostatics, the destinations are sinks of information and they are similar to negative charges, and the network is similar to a non-homogeneous dielectric media with variable dielectric constant (or permittivity coefficient). In one of the applications of our mathematical model based on the vector fields, we offer a scheme for energy efficient routing. Our routing scheme is based on changing the permittivity coefficient to a higher value in the places of the network where nodes have high residual energy, and setting it to a low value in the places of the network where the nodes do not have much energy left. Our simulations show that our method gives a significant increase in the network life compared to the shortest path and weighted shortest path schemes. Our initial focus is on the case where there is only one destination in the network, and later we extend our approach to the case where there are multiple destinations in the network. In the case of having multiple destinations, we need to partition the network into several areas known as regions of attraction of the destinations. Each destination is responsible for collecting all messages being generated in its region of attraction. The complexity of the optimization problem in this case is how to define regions of attraction for the destinations and how much communication load to assign to each destination to optimize the performance of the network. We use our vector field model to solve the optimization problem for this case. We define a vector field, which is conservative, and hence it can be written as the gradient of a scalar field (also known as a potential field). Then we show that in the optimal assignment of the communication load of the network to the destinations, the value of that potential field should be equal at the locations of all the destinations. Another application of our vector field model is to find the optimal locations of the destinations in the network. We show that the vector field gives the gradient of the cost function with respect to the locations of the destinations. Based on this fact, we suggest an algorithm to be applied during the design phase of a network to relocate the destinations for reducing the communication cost function. The performance of our proposed schemes is confirmed by several examples and simulation experiments. In another part of this work we focus on the notions of responsiveness and conformance of TCP traffic in communication networks. We introduce the notion of responsiveness for TCP aggregates and define it as the degree to which a TCP aggregate reduces its sending rate to the network as a response to packet drops. We define metrics that describe the responsiveness of TCP aggregates, and suggest two methods for determining the values of these quantities. The first method is based on a test in which we drop a few packets from the aggregate intentionally and measure the resulting rate decrease of that aggregate. This kind of test is not robust to multiple simultaneous tests performed at different routers. We make the test robust to multiple simultaneous tests by using ideas from the CDMA approach to multiple access channels in communication theory. Based on this approach, we introduce tests of responsiveness for aggregates, and call it CDMA based Aggregate Perturbation Method (CAPM). We use CAPM to perform congestion control. A distinguishing feature of our congestion control scheme is that it maintains a degree of fairness among different aggregates. In the next step we modify CAPM to offer methods for estimating the proportion of an aggregate of TCP traffic that does not conform to protocol specifications, and hence may belong to a DDoS attack. Our methods work by intentionally perturbing the aggregate by dropping a very small number of packets from it and observing the response of the aggregate. We offer two methods for conformance testing. In the first method, we apply the perturbation tests to SYN packets being sent at the start of the TCP 3-way handshake, and we use the fact that the rate of ACK packets being exchanged in the handshake should follow the rate of perturbations. In the second method, we apply the perturbation tests to the TCP data packets and use the fact that the rate of retransmitted data packets should follow the rate of perturbations. In both methods, we use signature based perturbations, which means packet drops are performed with a rate given by a function of time. We use analogy of our problem with multiple access communication to find signatures. Specifically, we assign orthogonal CDMA based signatures to different routers in a distributed implementation of our methods. As a result of orthogonality, the performance does not degrade because of cross interference made by simultaneously testing routers. We have shown efficacy of our methods through mathematical analysis and extensive simulation experiments

Design Optimization of Multi-Sink Sensor Networks by Analogy to Electrostatic Theory

In this work we introduce a new mathematical tool for optimization of routes, and topology design in wireless sensor networks. We introduce a vector field formulation that models communication in the network, and routing is performed in the direction of this vector field at every location of the network. The magnitude of the vector field at every location represents the density of amount of data that is being transited through that location. We define the total communication cost in the network as the integral of a quadratic form of the vector field over the network area. Our mathematical machinery is based on partial differential equations analogous to the Maxwell equations in electrostatic theory. We use our vector field model to solve the optimization problem for the case in which there are multiple destinations (sinks) in the network. In order to optimally determine the destination for each sensor, we partition the network into areas, each corresponding to one of the destinations. We define a vector field, which is conservative, and hence it can be written as the gradient of a scalar function (also known as a potential function). Then we show that in the optimal assignment of the communication load of the network to the destinations, the value of that potential function should be equal at the locations of all the destinations. Also, we show that such an optimal partitioning of the network load among the destination is unique, and we give iterations to find the optimal solution

Using Direct Sequence Spread Spectrum to Determine the Responsiveness of a TCP Aggregate to Packet Drops

In this paper we introduce a test through which the responsiveness of a TCP aggregate can be measured. The first introduced test is based on dropping a few packets from the aggregate and measuring the resulting rate decrease of that aggregate. This kind of test is not robust to multiple simultaneous tests performed at different routers. Extensions are done to make the test robust to multiple simultaneous tests by inspiring from the CDMA approach in the literature of multiple access channels in communication theory. The measurements of responsiveness can be utilized for different purposes like congestion control or mitigating a Distributed Denial of Service Attack

Predictors of Leisure Participation in 6 -14 Years Old Children with Cerebral Palsy: Structural Equation Modeling

AbstractObjective: The aim of this study was to test a model of child,family and environment and identify factors affecting intensity of leisure participation by children with cerebral palsy (CP).Materials & Methods: in this cross-sectional study,232 children with cerebral palsy (141 boys and 91 girls), age range 6 to 14 years and their parents were selected from 4 schools with special needs and 5 rehabilitation center through available sampling in Shiraz city. To evaluate leisure participation, we used the Persian version of Children’s Assessment of Participation and Enjoyment (CAPE) completed by participants. Demographic questionnaires, Craig Hospital Inventory of Environmental Factors (CHIEF), Strengths and Difficulties Questionnaire (SDQ), Family Environmental Scale (FES), SPARCLE cognitive level and parent's version of Gross Motor Function Classification System, Manual Ability Classification System and Communication Function Classification System were send to parents with some necessary explanations and completed. Structural equation modeling was used to test the model hypothesis. SPSS18 and AMOS16 were used for statistical data analysis. Results: Comparative fit index indicated a moderate to good fit model. The presented model explains 44% of the variance for intensity of participation. Constructs such as Family Activity Orientation with standardized total effect of (.31) and path coefficients P< .05 has shown most significant direct effect on participation, after that higher gross motor function (-.26), higher manual ability (-.19), communication function (-.17), higher cognitive level (-.16), more brothers and sisters in family (.15) and less emotional- behavioral problems (-.15) have shown direct effect on intensity of participation. Family Structures & Relationships (.17) and unsupportive environment constructs (-.14) have shown indirect but significant effect (P< .05). The relationship between family education level and income with participation were not significant (P>.05).Conclusion: Intensity of CP children participation is influenced by child, family and environmental factors. Parent's knowledge of recreational activities and their preferences to participation in leisure and recreations give children more opportunities to participate. higher gross motor function, manual ability, and communication function have an important role in participation. Family structure means family cohesion, roles organization, and conflicts between family members and also encountering physical, attitudinal and structural barriers in the home and community change children participation pattern indirectly. This study suggests therapists to support children’s behavior, family relationships and involvement in community activities and optimizing physical function for children who have limitations in self-mobility to enhance their participation

Nephroprotective effect of Gallic acid against mercuric chloride (HgCl2) induced damage in rats

Introduction: Mercury has hematotoxic, hepatotoxic, neurotoxic, nephrotoxic and genotoxic effects. Tissue damage induced by mercuric chloride (HgCl2) is associated with the promotion of oxidative stress. In this study, Gallic acid (GA), as potent antioxidant compound, was examined against mercuric chloride (HgCl2)-induced kidney injury in Wistar rats. Methods and Results: In this experimental study, animals were divided into five groups (n=7). Groups 1 and 2 respectively received normal saline (2 ml/kg, orally.) and HgCl2 (0.4 mg/kg, orally) for 28 consecutive days. Group 3 only received GA (200 mg/kg, orally) for 28 consecutive days. Groups 4 and 5 received orally GA at doses of 50 and 200 mg/kg, respectively, one hour after administration of HgCl2 for 28 consecutive days. Then On the 29th day, the rats were sacrificed, and blood samples were collected to determine biochemical parameters such as serum creatinine (Cr) and blood urea nitrogen (BUN) levels. For oxidative stress evaluation, malondialdehyde (MDA) and reduced glutathione (GSH) levels and also catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were evaluated in left kidney tissue. The right kidney was used for histological examination. The results obtained from our study showed a significant increase in the levels of MDA, Cr and BUN, and decrease of GSH, CAT and SOD after ingestion of HgCl2 (p<0.05). Pre-treatment with GA showed diminished in the levels of MDA, Cr and BUN and enhanced of GSH, CAT, GPx and SOD activity (p<0.05). Additionally the nephroprotective effect of the GA was established by the histological evaluation of the kidneys. Conclusions: Our results indicate that GA has protective effect against HgCl2-induced renal damage probably by scavenging free radicals, reducing the oxidative stress, and increasing the antioxidant defense mechanism

Sensory processing patterns and sleep quality in primary school children

ABSTRACTObjectives: Sensory processing and sleep quality affect children's academic performance and their quality of life. The purpose of this study was to investigate the relationship between sensory processing patterns and sleep quality in primary schoolchildren.Materials & Methods: In this cross-sectional study, 231 primary school students aged 7 to 12 years old (133 girls and 98 boys, mean age of 8.68±1.51) who were studying in schools in Tehran were randomly selected through cluster sampling. Researchers distributed a questionnaire for children's sleep habits to assess the quality of sleep and a Sensory Profile Questionnaire to assess the sensory processing patterns.Results: In this study, we found a meaningful moderate relationship between sensory processing patterns and the general scores of sleep habits (p <0.001) and each of the patterns of sensory processing (avoidance, sensitivity, seeking, and registration) had a negative relationship with areas of sleep habits (p =.005). Also, there was a significant difference between children who had more challenges with sleep and children with normal sleep patterns in sensory processing; mean differences in all four sensory quadrants were significant (p <001).Conclusion: Sensory processing patterns and sleep habits in primary school children have moderate correlation. Occupational therapists should consider the relationship between sensory challenges and sleep habits during their practice decisions with sensory challenges and sleep problems. Better sleep may occur with attention to sensory needs within the sleep routines. When sleep is better, this may lead to improved quality of life for the family and student performance at school

Identifying the Elements and Components of the Curriculum of the Books Din va Zendegi (Religion and Life) Based on a Transpersonal View: A Qualitative Study

This study aims to identify the elements and components of the curriculum of the books Din va Zendegi (Religion and Life) in senior high schools based on a transpersonal view. The method of this study was developmental-applicative in terms of purpose, and in terms of the type of method, content analysis was based on three-stage coding (open, axial , and selective). The field of study included all the experts and teachers in curriculum planning, educational sciences, and educational management, and through the purposive sampling method, the teachers with the desired qualifications were interviewed in a semi-structured way until arriving at the theoretical saturation of the findings, the number of study samples reached 12 teachers. To analyze the data obtained from the interviews, three-step coding methods were used. According to the findings, 18 categories and 5 elements were identified from the coding of the interviews: the objective element with 5 categories, the evaluation element with 4 categories, the elements of learners’ characteristics, and content and method with 3 categories, which were identified as the elements and contents  for the books Din va Zendegi (Religion and Life) in senior high schools based on a transpersonal view. The identified elements and components can be used in designing a model based on a transpersonal view in the curriculum of the books Din va Zendegi