223 research outputs found

    Review on Cloud Computing Security Challenges

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    In this paper, security issues associated with cloud computing are reviewed. Additionally, the types of cloud and service models have also been pointed out. Cloud computing has ruled the data innovation industry as of late. Giant data centersthat provide cloud services are been set up due to the global approval of cloud and virtualization innovations. Cloud computing is characterized as a web-based software service since Information Technology (IT) resources like network, server, storage, and so on are based on the Web. Along these lines, cloud computing services can be utilized at any place and whenever on the Personal Computer (PC) or smart mobile phones. In light of the on-demand, adaptable and versatile administration it can give, a considerable measure of companies that beforehand deployed locally has moved their organizations to the cloud. Although cloud computing brings a whole lot of advantages, many security challenges have been brought up to both cloud providers and clients

    Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

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    In this paper, a conventional indirect stator flux oriented controlled (ISFOC) induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS) scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed from measured terminal voltages and currents. The IP gains speed controller and PI gains current controller are calculated and tuned at each sampling time according to the new estimated rotor speed. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load; and stability is preserved. Experimental results obtained with a general-purpose 1-kW induction machine are presented showing the effectiveness of the proposed approach in terms of dynamic performance

    Intra-Ring Wood Density and Dynamic Modulus of Elasticity Profiles for Black Spruce and Jack Pine from X-ray Densitometry and Ultrasonic Wave Velocity Measurement

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    Currently, ultrasonic measurement is a widely used nondestructive approach to determine wood elastic properties, including the dynamic modulus of elasticity (DMOE). DMOE is determined based on wood density and ultrasonic wave velocity measurement. The use of wood average density to estimate DMOE introduces significant imprecision: Density varies due to intra-tree and intra-ring differences and differing silvicultural treatments. To ensure accurateDMOEassessment, we developed a prototype device to measure ultrasonic wave velocity with the same resolution as that provided by the X-ray densitometer for measuring wood density. A nondestructive method based on X-ray densitometry and the developed prototype was applied to determine radial and intra-ring wood DMOE profiles. This method provides accurate information on wood mechanical properties and their sources of variation. High-order polynomials were used to model intra-ring wood density and DMOE profiles in black spruce and jack pine wood. The transition from earlywood to latewood was defined as the inflection point. High and highly significant correlations were obtained between predicted and measured wood density and DMOE. An examination of the correlations between wood radial growth, density, and DMOE revealed close correlations between density and DMOE in rings, earlywood, and latewood

    Preface

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    Preface

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    QCOF: New RPL Extension for QoS and Congestion-Aware in Low Power and Lossy Network

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    Low power and lossy networks (LLNs) require a routing protocol under real-time and energy constraints, congestion aware and packet priority. Thus, Routing Protocol for Low power and lossy network (RPL) is recommended by Internet Engineering Task force (IETF) for LLN applications. In RPL, nodes select their optimal paths towards their preferred parents after meeting routing metrics that are injected in the objective function (OF). However, RPL did not impose any routing metric and left it open for implementation. In this paper, we propose a new RPL objective function which is based on the quality of service (QoS) and congestion-aware. In the case paths fail, we define new RPL control messages for enriching the network by adding more routing nodes. Extensive simulations show that QCOF achieves significant improvement in comparison with the existing objective functions, and appropriately satisfies real-time applications under QoS and network congestion.info:eu-repo/semantics/publishedVersio

    An unusual etiology of posttraumatic Collet–Sicard Syndrome: a case report

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    Posttraumatic Unilateral paralysis of the last four cranial nerves (IX-XI), known as collet-Sicard syndrome, is rare following closed head injury. A 21-year-old man presented with slurred speech, hoarseness voice and difficulty swallowing his saliva following closed head trauma. The cranial nerve examination revealed left sided severe dysfunction of cranial nerves VII, IX, X, XI, and XII.A CT-Scan of the neck was performed demonstrating a fracture of the left styloid process at the base of the skull.The Magnetic Resonance Imaging showed unusually well seen lower cranial nerves due to nerve edema. The patient was managed conservatively with steroids and regular sessions of neuromuscular and orthophonic rehabilitation.The nutrition had to be administered by gastrostomy since he was unable to swallow.Six months after the injury a total neurological recovery was noted.We present the exceptional case of Collet-Sicard Syndrome caused by styloid process fracture.Pan African Medical Journal 2016; 2

    Multi-agent Adaptive Architecture for Flexible Distributed Real-time Systems

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    Recent critical embedded systems become more and more complex and usually react to their environment that requires to amend their behaviors by applying run-time reconfiguration scenarios. A system is defined in this paper as a set of networked devices, where each of which has its own operating system, a processor to execute related periodic software tasks, and a local battery. A reconfiguration is any operation allowing the addition-removal-update of tasks to adapt the device and the whole system to its environment. It may be a reaction to a fault or even optimization of the system functional behavior. Nevertheless, such scenario can cause the violation of real-time or energy constraints, which is considered as a critical run-time problem. We propose a multi-agent adaptive architecture to handle dynamic reconfigurations and ensure the correct execution of the concurrent real-time distributed tasks under energy constraints. The proposed architecture integrates a centralized scheduler agent (ScA) which is the common decision making element for the scheduling problem. It is able to carry out the required run-time solutions based on operation research techniques and mathematical tools for the system's feasibility. This architecture assigns also a reconfiguration agent (RA p ) to each device p to control and handle the local reconfiguration scenarios under the instructions of ScA. A token-based protocol is defined in this case for the coordination between the different distributed agents in order to guarantee the whole system's feasibility under energy constraints.info:eu-repo/semantics/publishedVersio

    System and method for operating a follower vehicle in a vehicle platoon

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    Patent no. US9927816B2A method for operating a follower vehicle in a vehicle platoon includes determining, during operation, whether the follower vehicle is operating in a normal state or an abnormal state based on an operation condition of a component of the follower vehicle, or a communication between the follower vehicle and a preceding vehicle in the vehicle platoon. The method further includes selecting a first control mode if the follower vehicle is in the normal state and a second control mode if the follower vehicle is in the abnormal state so as to control movement of the follower vehicle using the selected control mode. In the first control mode, the follower vehicle uses communication data received from the preceding vehicle in the vehicle platoon to control its movement. In the second control mode, the follower vehicle uses data obtained by one or more of its sensors to control its movement.info:eu-repo/semantics/publishedVersio
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