446 research outputs found

    High speed train communications systems using free space optics

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    In this work, we propose a broad-band free space optical (FSO) wireless communications system for high-speed trains. The system consists of optical transceivers positioned outside the train and along the railway track. The train receivers are in the coverage area of base stations positioned along the railway track to ensure continuous link availability. In this paper, we present modelling of two cases for over-ground and underground train systems before embarking to practically implement the system in our research laboratory. Also discussed is the protocol for the data distribution along the track as well as the initial experimental demonstration of the proposed link

    Antiviral Activity of Some Plants Used in Nepalese Traditional Medicine

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    Methanolic extracts of 41 plant species belonging to 27 families used in the traditional medicine in Nepal have been investigated for in vitro antiviral activity against Herpes simplex virus type 1 (HSV-1) and influenza virus A by dye uptake assay in the systems HSV-1/Vero cells and influenza virus A/MDCK cells. The extracts of Astilbe rivularis, Bergenia ciliata, Cassiope fastigiata and Thymus linearis showed potent anti-herpes viral activity. The extracts of Allium oreoprasum, Androsace strigilosa, Asparagus filicinus, Astilbe rivularis, Bergenia ciliata and Verbascum thapsus exhibited strong anti-influenza viral activity. Only the extracts of A. rivularis and B. ciliata demonstrated remarkable activity against both viruses

    Single carrier optical FDM in visible light communication

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    In this paper a comparison between a spiral and a strip shaped LED is presented in terms of the maximum link distance achievable in visible light based car to car communications (VLC-C2C). The transmitted data is recovered from the frame brightness of the video signal. The intensity modulated LED is captured from two scenarios, using a focused and unfocused camera. A data rate of 180 bps with the bit error rate performance below the FEC limit of 10-3 at a distance of 100 cm is successfully achieved, sufficient for transmitting road safety messages for VLC-C2C. It is shown that under the same conditions, the strip LED can effectively recover the data from a greater distance than its spiral counterpart

    Handover - Enabling Learning in Communication for Safety (HELiCS): a report on achievements at two hospital sites

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    The provision of health care is becoming increasingly complex and fragmented.1,2 As a result, to ensure continuity of care, the handover of clinical tasks is becoming more frequent and important. However, the general lack of clinical handover planning and training in handover communication creates unacceptable risks for patients.1 Not surprisingly, clinical handover has been identified as a major international policy and research priority

    Vehicular Visible Light Positioning using Receiver Diversity with Machine Learning

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    This paper proposes a 2-D vehicular visible light positioning (VLP) system using existing streetlights and diversity receivers. Due to the linear arrangement of streetlights, traditional positioning techniques based on triangulation or similar algorithms fail. Thus, in this work, we propose a spatial and angular diversity receiver with machine learning (ML) techniques for VLP. It is shown that a multi-layer neural network (NN) with the proposed receiver scheme outperforms other ML algorithms and can offer high accuracy with root mean square (RMS) error of 0.22 m and 0.14 m during the day and night time, respectively. Furthermore, the NN shows robustness in VLP across different weather conditions and road scenarios. The results show that only dense fog deteriorates the performance of the system due to reduced visibility across the road

    Experimental evaluation of adaptive maximum power point tracking for a standalone photovoltaic system

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    The adaptability of maximum power point tracking (MPPT) of a solar PV system is important for integration to a microgrid. Depending on what fixed step-size the MPPT controller implements, there is an impact on settling time to reach the maximum power point (MPP) and the steady state operation for conventional tracking techniques. This paper presents experimental results of an adaptive tracking technique based on Perturb and Observe (P&O) and Incremental Conductance (IC) for standalone Photovoltaic (PV) systems under uniform irradiance and partial shading conditions. Analysis and verification of measured and MATLAB/Simulink simulation results have been carried out. The adaptive tracking technique splits the operational region of the solar PV’s power–voltage characteristic curve into four and six operational sectors to understand the MPP response and stability of the technique. By implementing more step-sizes at sector locations based on the distance of the sector from the MPP, the challenges associated with fixed step-size is improved on.The measured and simulation results clearly indicate that the proposed system tracks MPP faster and displays better steady state operation than conventional system. The proposed system’s tracking efficiency is over 10% greater than the conventional system for all techniques. The proposed system has been under partial shading condition has been and it outperforms other techniques with the GMPP achieved in 0.9 s which is better than conventional techniques

    Consulting (in Writing) to the Corporation: Principles and Pragmatics

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    Provenance information provides a useful basis to verify whether a particular application behavior has been adhered to. This is particularly useful to evaluate the basis for a particular outcome, as a result of a process, and to verify if the process involved in making the decision conforms to some pre-defined set of rules. This is significant in a healthcare scenario, where it is necessary to demonstrate that patient data has been processed in a particular way. Understanding how provenance information may be recorded, stored, and subsequently analyzed by a decision maker is therefore significant in a service oriented architecture, which involves the use of third party services over which the decision maker does not have control. The aggregation of data from multiple sources of patient information plays an important part in subsequent treatments that are proposed for a patient. A tool to navigate through and analyze such provenance information is proposed, based on the use of a portal framework that allows different views on provenance information to co-exist. The portal enables users to add custom portlets enabling application specific views that would facilitate particular decision making
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