1,322 research outputs found

    A Nurse is to a Patient What a Mother is to a Child

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    A physician\u27s tribute the profession of nursing

    FCC structured ferromagnetic ultra-thin films with two spin layers described by fourth order perturbed Heisenberg Hamiltonian

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    Fourth order perturbation was applied to study a small variation of the azimuthal angle of spin of fcc structured ferromagnetic thin films with two spin layers. The variation of magnetic energy and the orientation of magnetic easy axis with the fourth order magnetic anisotropy constant in two spin layers was investigated. When the second order magnetic anisotropy constant at the top spin layer is higher than that of bottom spin layer, the total magnetic energy is slightly higher. Some spikes appeared in the 2D plot of of magnetic energy versus azimuthal angle of spin. According to the 3D plots, the peak value of the magnetic energy gradually decreases with the increase of the stress induced anisotropy constant, and thereafter the peak value of the magnetic energy gradually increases with the increase of the stress induced anisotropy constant. The angle between magnetic easy and hard directions was not 90 degrees. The magnetic easy and hard directions of the film with a higher second order magnetic anisotropy constant of top layer are different from the magnetic easy and hard directions of the film with a lower second order magnetic anisotropy constant of top layer. When the second order magnetic anisotropy constant of the bottom layer is increased, the total magnetic energy does not change

    Disaster-Resilient Control Plane Design and Mapping in Software-Defined Networks

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    Communication networks, such as core optical networks, heavily depend on their physical infrastructure, and hence they are vulnerable to man-made disasters, such as Electromagnetic Pulse (EMP) or Weapons of Mass Destruction (WMD) attacks, as well as to natural disasters. Large-scale disasters may cause huge data loss and connectivity disruption in these networks. As our dependence on network services increases, the need for novel survivability methods to mitigate the effects of disasters on communication networks becomes a major concern. Software-Defined Networking (SDN), by centralizing control logic and separating it from physical equipment, facilitates network programmability and opens up new ways to design disaster-resilient networks. On the other hand, to fully exploit the potential of SDN, along with data-plane survivability, we also need to design the control plane to be resilient enough to survive network failures caused by disasters. Several distributed SDN controller architectures have been proposed to mitigate the risks of overload and failure, but they are optimized for limited faults without addressing the extent of large-scale disaster failures. For disaster resiliency of the control plane, we propose to design it as a virtual network, which can be solved using Virtual Network Mapping techniques. We select appropriate mapping of the controllers over the physical network such that the connectivity among the controllers (controller-to-controller) and between the switches to the controllers (switch-to-controllers) is not compromised by physical infrastructure failures caused by disasters. We formally model this disaster-aware control-plane design and mapping problem, and demonstrate a significant reduction in the disruption of controller-to-controller and switch-to-controller communication channels using our approach.Comment: 6 page

    Optimized reduction approach of congestion in mobile ad hoc network based on Lagrange multiplier

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    Over the past decades, computer networks have experienced an outbreak and with that came severe congestion problems. Congestion is a crucial determinant in the delivery of delay-sensitive applications (voice and video) and the quality of the network. in this paper, the Lagrangian optimization rate, delay, packet loss, and congestion approach (LORDPC) are presented. A congestion avoidance routing method for device-to-device (D2D) nodes in an ad hoc network that addresses the traffic intensity problem. The method of Lagrange multipliers is utilized for active route election to dodge heavy traffic links. To demonstrate the effectiveness of our proposed method, we applied extensive simulation that presents path discovery and selection. Results show that LORDPC decreases delay and traffic intensity while maintaining a high bitrate and low packet loss rate and it outperformed the ad hoc on-demand distance vector (AODV) protocol and the Lagrangian optimization rate, delay, and packet loss, approach (LORDP)

    Optimal resource allocation for route selection in ad-hoc networks

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    Nowadays, the selection of the optimum path in mobile ad hoc networks (MANETS) is being an important issue that should be solved smartly. In this paper, an optimal path selection method is proposed for MANET using the Lagrange multiplier approach. The optimization problem considers the objective function of maximizing bit rate, under the constraints of minimizing the packet loss, and latency. The obtained simulation results show that the proposed Lagrange optimization of rate, delay, and packet loss algorithm (LORDP) improves the selection of optimal path in comparison to ad-hoc on-demand distance vector protocol (AODV). We increased the performance of the system by 10.6 Mbps for bit rate and 0.133 ms for latency

    Pelaksanaan Pendekatan Scientific pada Pembelajaran Fisika di SMA Negeri di Kabupaten Pidie

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    This study examines the problem of how the implementation of the scientific approach has been carried out in Physics learning in SMA Negeri Pidie district. The purpose of this research is to know how far the implementation of scientific approach in Physics subject in SMA Negeri in Pidie district. Subjects in this study were all physics teachers of SMAN applying Curriculum 2013 that is SMAN 1 Sigli, SMAN 2 Sigli, SMAN Unggul Sigli, SMAN 1 Mutiara, and SMAN 1 Sakti. While the Object is the plan of implementation of learning in the teacher and questionnaire implementation of scientific approach. The type of this research is qualitative research. Data collection in this research is done by method (1) questionnaire, and (2) documentation. The data were analyzed descriptive qualitative using percentage equation. The results showed that the implementation of the scientific approach in Physics learning in SMA Negeri in Pidie district has been running well. The average percentage of the implementation of the scientific approach of 77.85% means that teachers always take a scientific approach in the learning process