235 research outputs found

    The HSS/SNiC : a conceptual framework for collapsing security down to the physical layer

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    This work details the concept of a novel network security model called the Super NIC (SNIC) and a Hybrid Super Switch (HSS). The design will ultimately incorporate deep packet inspection (DPI), intrusion detection and prevention (IDS/IPS) functions, as well as network access control technologies therefore making all end-point network devices inherently secure. The SNIC and HSS functions are modelled using a transparent GNU/Linux Bridge with the Netfilter framework

    DC biased input stage with differential photocurrent sensing for VLC front-ends

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    The reverse bias voltage across the PIN photodiode is essential for the photodiode to operate in the photoconductive mode. This paper presents an input bias stage with differential photocurrent sensing for VLC front-ends. The bias voltage is provided from within the transimpedance amplifier’s (TIA) circuit eliminating the need of external bias voltage. The amount of bias voltage could be optimised according to the photodiode required sensitivity and capacitance. The differential configuration makes the TIA immune to any common mode noise. The proposed method is applied to a hypothetical TIA and results are compared with single ended structure. Simulation results showed that using this approach it is possible to achieve a transimpedance gain of 120 dBΩ over a maximum bandwidth of 14.5 MHz with a common mode rejection ratio of 61 dB while the circuit provides a controlled bias voltage of up to 6 V across the PIN photodiode eliminating the need for external bias voltage source

    Flows consumption assessment study for fuel cell vehicles: Towards a popularization of FCVs technology

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    Climate change can be caused by a major part from the high fossil fuel usage and consumption in transportation field. It contributes to the increase of pollutant emissions, which lead to serious problems on human health in addition to the environmental degradation phenomena. Hydrogen fuel cell vehicles (FCVs) are expected to have a significant impact in meeting both energy security and environmental concerns globally. Starting for the premise that public acceptance and attitudes studies were generally positive towards hydrogen and fuel cells vehicles, even if the public knows few things about this technology; authors then got the idea to present a simplified scientific work dealing with the description of the energy management and flows calculations on board FCVs. This work aims not only to the popularization of this technology but also to outreach people about its sustainable character. A variable driving profile is adopted with a total distance of 1 km with duration of 60 s. The total hydrogen amount consumed is 1,34 g km−1. Under pressure, only 5 kg of hydrogen give optimal autonomy of 700 km, which is really competitive to the conventional gasoline cars. A nice advantage is yet observed and its concerns the environmental profits

    A survey on smart traffic network control and optimization

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    In the current day and age, traffic in urban areas is becoming more and more complex leading to congested roads and intersections. Hence, the need for sophisticated traffic control system to reduce the congestion and provide better flow management. In this paper, we present briefly the basic notions and the most important parameters that affects the traffic control. Then, we provide a survey on the main flow management systems that are available in the literature. Some possible future research works and propositions on intelligent traffic control are also provided

    Robust fault estimation for stochastic Takagi-Sugeno fuzzy systems

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    Nowadays, industrial plants are calling for high-performance fault diagnosis techniques to meet stringent requirements on system availability and safety in the event of component failures. This paper deals with robust fault estimation problems for stochastic nonlinear systems subject to faults and unknown inputs relying on Takagi-Sugeno fuzzy models. Augmented approach jointly with unknown input observers for stochastic Takagi-Sugeno models is exploited here, which allows one to estimate both considered faults and full system states robustly. The considered unknown inputs can be either completely decoupled or partially decoupled by observers. For the un-decoupled part of unknown inputs, which still influence error dynamics, stochastic input-to-state stability properties are applied to take nonzero inputs into account and sufficient conditions are achieved to guarantee bounded estimation errors under bounded unknown inputs. Linear matrix inequalities are employed to compute gain matrices of the observer, leading to stochastic input-to-state-stable error dynamics and optimization of the estimation performances against un-decoupled unknown inputs. Finally, simulation on wind turbine benchmark model is applied to validate the performances of the suggested fault reconstruction methodologies

    Effectiveness-implementation hybrid type 2 study evaluating an intervention to support ‘information work’ in dementia care: an implementation study protocol

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    Introduction Patients with long-term conditions consistently report a lack of information around services and support available to them. This unmet need for information is significant among people with dementia and family carers. A quality improvement intervention is being carried out to tackle this issue as part of a co-creation initiative in the North East of England (UK). The intervention consists of the dissemination (via the local Community Mental Health Services for Older People) of a leaflet about services available to people with dementia and their family carers in the study site. This protocol is reported in accordance with the Standards for Reporting Implementation Studies. Methods and analysis This effectiveness–implementation hybrid type 2 study aims at understanding (1) the unfolding and outcomes of the implementation strategy, (2) the outcomes of the intervention (for people with dementia and family carers, staff implementing the intervention and local service providers) and (3) the contribution of co-creation to the design and implementation of the intervention and its outcomes. The prospective theory of change of the intervention articulated by local stakeholders is used as a reference framework against which to assess the implementation and outcomes of the intervention. Evaluation data will be collected through in-depth interviews with people with dementia and family carers receiving the intervention, staff implementing the intervention and managers from local service providers. Referral data from local service providers will be collected to triangulate the interview data. A focus group with key stakeholders will support the sense-making of findings. The realist configuration of mechanism–context–outcome, operationalised using an information behaviour model, will inform data analysis and interpretation. Ethics and dissemination Ethical and research governance approvals have been obtained from the West Midlands—South Birmingham Research Ethics Committee. The results of the study will be submitted for publication in peer-reviewed journals and disseminated through conferences

    Indoor visible light communication localization system utilizing received signal strength indication technique and trilateration method

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    Visible light communication (VLC) based on light-emitting diodes (LEDs) technology not only provides higher data rate for indoor wireless communications and offering room illumination but also has the potential for indoor localization. VLC-based indoor positioning using the received optical power levels from emitting LEDs is investigated. We consider both scenarios of line-of-sight (LOS) and LOS with non-LOS (LOSNLOS) positioning. The performance of the proposed system is evaluated under both noisy and noiseless channel as is the impact of different location codes on positioning error. The analytical model of the system with noise and the corresponding numerical evaluation for a range of signal-to-noise ratio (SNR) are presented. The results show that an accuracy of 12 dB

    Modelling and Synchronisation of Delayed Packet-Coupled Oscillators in Industrial Wireless Sensor Networks

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    In this paper, a Packet-Coupled Oscillators (PkCOs) synchronisation protocol is proposed for time-sensitive Wireless Sensor Networks (WSNs) based on Pulse-Coupled Oscillators (PCO) in mathematical biology. The effects of delays on synchronisation performance are studied through mathematical modelling and analysis of packet exchange and processing delays. The delay compensation strategy (i.e., feedforward control) is utilised to cancel delays effectively. A simple scheduling function is provided with PkCOs to allocate the packet transmission event to a specified time slot, by configuring reference input of the system to a non-zero value, in order to minimise the possibility of packet collision in synchronised wireless networks. The rigorous theoretical proofs are provided to validate the convergence and stability of the proposed synchronisation scheme. Finally, the simulations and experiments examine the effectiveness of PkCOs with delay compensation and scheduling strategies. The experimental results also show that the proposed PkCOs algorithm can achieve synchronisation with the precision of 26.3μs26.3\mu s (11 tick)

    Autonomous drone control within a Wi-Fi network

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    Over the past ten years there has been a substantial growth in the expenditure of quadcopter drones. Whilst the greatest expense remains with the military, drones are finding increased use in commercial applications such as construction, agriculture, oil and gas and cinematography. However, a major shortcoming of the quadcopter drone is its limited flight time of 30 minutes. Recharging and replacing batteries, significantly impedes and interrupts the desired drone mission. A possible solution is to deploy a number of drones connected and communicating over a network enabling greater area coverage for the same flight time. This paper describes the development of a multiple drone network constructed from commercially available drones. A single autonomous drone is initially constructed which is able to follow a predefined flight plan. The single autonomous drone is developed to enable the formation of a network with other similarly constructed autonomous drones. Flight command codes are able to be transmitted between drones to instruct the receiving drone to fly a particular flight path. Results presented confirm the performance of the controlled flightpath of the autonomous drone and the ability to pass flight command codes between drones across the network

    Steering Mirror System with Closed-Loop Feedback for Free-Space Optical Communication Terminals

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    Precision beam pointing plays a critical role in free-space optical communications terminals in uplink, downlink and inter-satellite link scenarios. Among the various methods of beam steering, the use of fast steering mirrors (FSM) is widely adopted, with many commercial solutions employing diverse technologies, particularly focusing on small, high-bandwidth mirrors. This paper introduces a method using lightweight, commercial off-the-shelf components to construct a custom closed-loop steering mirror platform, suitable for mirror apertures exceeding 100 mm. The approach involves integrating optical encoders into two off-the-shelf open-loop actuators. These encoders read the signal reflected on purposefully diamond-machined knurled screw knobs, providing maximum contrast between light and dark lines. The resulting steering mirror has the potential to complement or replace FSM in applications requiring a larger stroke, at the expense of motion speed. In the presented setup, the mirror tilt resolution achieved based on the encoder closed-loop signal feedback is 45 μrad, with a mean slew rate of 1.5 mrad/s. Importantly, the steering assembly is self-locking, requiring no power to maintain a steady pointing angle. Using the mirror to actively correct for a constantly moving incoming beam, a 5-fold increase in concentration of the beam spot on the center of the detector was obtained compared to a fixed position mirror, demonstrating the mirrors ability to correct for satellite platform jitter and drift
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