The potential of artificial neural network technique in daily and monthly ambient air temperature prediction

Ambient air temperature prediction is of a concern in environment, industry and agriculture. The increase of average temperature results in natural disasters, higher energy consumption, damage to plants and animals and global warming. Ambient air temperature predictions are notoriously complex and stochastic models are not able to learn the non-linear relationships among the considered variables. Artificial Neural Network (ANN) has potential to capture the complex relationships among many factors which contribute to prediction. The aim of this study is to develop ANN for daily and monthly ambient air temperature prediction in Kerman city located in the south east of Iran. The mean, minimum and maximum ambient air temperature during the years 1961-2004 was used as the input parameter in Feed Forward Network and Elman Network. The values of R, MSE and MAE variables in both networks showed that ANN approach is a desirable model in ambient air temperature prediction, while the results of one day ahead mean temperature and one month ahead maximum temperature are more precise using Elman network

Cross layer routing and scheduling for multi-channel Wimax mesh networks

Broadband wireless networks are becoming increasingly popular due to their fast and inexpensive deployment and their capabilities of providing flexible and ubiquitous Internet access. Due to the limitation of shared resources in wireless mesh network such as bandwidth, spatial reuse is introduced for concurrent transmissions. The simultaneous transmissions face many challenges regarding interference on the ongoing transmission. To maximize the network performance of mesh networks in terms of spatial reuse, it is essential to consider a cross-layer for resource allocation in different layers such as the routing network layer, the scheduling resource allocation Media Access Control (MAC) layer and physical layer. Therefore, this thesis focuses on improving the spatial reuse for resource allocation mechanism including routing tree construction by taking into consideration the reliable path, channel assignment and scheduling algorithms. Firstly, a Fuzzy based Constructed Routing Tree (FLCRT) is proposed to incorporate fuzzy logic with routing to enable cognitive capability in packet forwarding for uplink or downlink communication. Secondly, the link-aware routing path is proposed to satisfy the connection lifetime and better routing stability for successful requirements of transmission using multi sponsor node technique. Then, a better understanding of reliability analysis is pursued in the context of homogeneous wireless network. Ultimately, heuristic resource allocation including channel assignment and centralized scheduling algorithms are proposed based on the cellular learning automata to enhance the number of concurrent transmissions in the network by efficiently reusing the spectrum spatially. The attempt of heuristic resource allocation algorithms is to find the maximal number of nodes that could transmit data concurrently. The numerical and simulation results show that FLCRT, Learning Automata Heuristic Channel Assignment (LAHCA), and Learning Automata Heuristic Centralized Scheduling (LAHCS) perform better in terms of scheduling length, channel utilization ratio, and average transmission delay as compared with the existing approaches. The proposed FLCRT scheme with respect to the number of subscriber station (SS) nodes performs better in decreasing the scheduling length, average transmission delay, and channel utilization ratio by 38%, 19%, and 38% compared with Interference-Load-Aware routing. LAHCA algorithm improves the number of channels in comparison with random selection algorithm by 8%. LAHCS algorithm using multi channels proposed by LAHCA can reduce the scheduling time, average transmission delay as well as enhance channel utilization ratio versus number of SS nodes by 7%, 8%, and 6% respectively compared with Nearest algorithm in higher traffic demands

Adaptive resource allocation for WiMAX mesh network

Worldwide Interoperability for Microwave Access is a technology used to enable fast and cost-effective network deployment as well as facilitating multimedia based services and applications available to the users. However, Interference constitutes a major constraint in the widespread use of shared resources for interaction among devices. In this paper, a greedy resource allocation mechanism, which consists of Learning Automata based Greedy Channel Assignment and Learning Automata based Greedy Centralized Scheduling algorithms, is presented to cope with interference as well as to improve spatial reuse in the resource allocation mechanism. Finally, the simulation results demonstrate that our proposed algorithms outperform existing approaches

Ultrasound Evaluation of Spinal Cord in Newborns with Sacral Pit

Background: Sacral pit is a shallow or deep dimple in the lower sacral region, with a reported prevalence of 3-5% among newborns. The aim of the present study was to investigate spinal cord abnormalities in newborns with sacral pit via ultrasound examinations. Methods: In this descriptive study, 3071 infants born at 34-42 weeks of gestation were studied in hospitals affiliated to Islamic Azad University of Mashhad, Iran during 2014-2015. Information including age, sex, and birth weight was recorded in a questionnaire. Infants with a sacral pit underwent ultrasonography; spinal shape and mobility in these infants were compared with their healthy counterparts. For statistical analysis, data were entered to Microsoft Excel software. Chi-square and student’s t-test were performed, using SPSS version 20. Results: Based on the findings, 1.6% of the studied infants were born with a sacral pit. The weight and age were not significantly different between healthy neonates and those with a sacral pit. The prevalence of sacral pit was higher in female cases (54.2%), although there was no significant difference between the genders. Ultrasound examination of the spinal cord revealed its normal position and motility in all newborns with a sacral dimple. Conclusion: The present results showed the normal shape and motility of the spinal cord in newborns with a sacral pit. Therefore, there was no correlation between sacral pit as a cutaneous marker and neural tube defects

Fault Tolerance Analysis Among Subscriber Stations in the WiMAX Mesh Network

The WiMAX mesh network based IEEE 802.16 standard provides maximum using of the bandwidth channel. Mesh WiMAX network is a promising technology by offering high data rate, broadband wireless access, high quality of service and large coverage area with the low cost of deployment. One of the most important issues in the WiMAX network is the failure of subscriber stations due to less power or mobility or etc during the relay multi hop transmission path so that knowing of the fault tolerant parameters such as connection resilience has received much attention recently. In this paper, we propose an analytical framework to estimate the connction availability and connection resilience for one node based on the Continuous Time Markov Chain (CTMC) using multiple back up nodes for the selection of sponsor nodes. The multiple backup sponsor node technique enhances the fault tolerance of network in front of failure of sponsor nodes. We also develop the analytical framework to analyze the connection resilience among subscriber stations in the mesh cluster. Knowing of the connection resilience improves the requirements of succeful transmission

A review on tissue engineering scaffolds and their function in regenerative medicine

 One of the challenges that medical sciences has long been facing is to find the best therapeutic method for the damaged tissues. The main purpose of tissue engineering and regenerative medicine is the development of biological implant or engineered tissues to repair, regenerate or replace the damaged tissue and maintain the organ function. At the moment, a lot of research has been done in the field of nanotechnology on the application of nanomaterials in medicine, because the surface of these nanomaterials increases with decreasing their size with change or increases in effect concommitantly. In recent decades, the production of medical textiles (Including nano fibers) has been provided good services to the regenerative medicine. In the field of biomedical applications, it is often necessary to combine biological and medical sciences with materials science and engineering. One of the most important application of tissue engineering is the usage of nanofiber matrix as scaffolds for the cell growth and proliferation. In this paper, various types of engineered scaffolds and their functions have been presented and evaluated. &nbsp

Improving the communication path reliability of WiMAX mesh network using multi sponsor technique

Recently Worldwide Interoperability for Microwave Access (WiMAX) mesh network has emerged as a promising wireless technology in order to enable fast, cost-effective network deployment. However, achieving these requirements is a daunting task due to the mesh subscriber station failures in the presence of the adversarial environment. In fact, mesh subscriber station failure is one of the important challenges in satisfying the requirements of the communication path in the WiMAX mesh network. To cope with the node failures during communication path bypassing the intermediate nodes, the enhancement of communication path reliability is of the utmost importance in the WiMAX mesh network. In this paper, a new technique based on multi sponsor nodes is presented to enhance the reliability of the multi hop communication path. Markov model based on the multi sponsor nodes is also applied to enhance the communication path reliability when the network face with malfunctioning nodes. Ultimately, a generic model based on the stochastic attribution of WiMAX mesh network is developed to measure the reliability of the multi hop communication path. Consequently, multi sponsor technique in WiMAX could more thoroughly improve the reliability of the communication path in the WiMAX mesh network