348 research outputs found

    Strategies for Improving Indian Railways’ Market Share of Port Based Coal Traffic: A Diagnostic Study

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    India is a vast country. After its independence in 1947, it steadily lost its position in international trade. With the beginning of economic liberalization in 1991, it has taken new initiatives in integrating itself with the world economy. Import restrictions have been removed for many commodities. One of the major impacts of liberalization has been on infrastructure: railways, roadways, ports and airports. Significant changes have also taken place in the composition of imported and exported commodities. Due to these changes, new challenges are being faced on the infrastructure front. One of the challenges is to rectify the mismatch of available infrastructure at ports where a modal change of commodities that are either imported or exported takes place. This paper examines such issues with a specific focus on improving infrastructure required for integration of railways and ports. This is achieved by focusing on coal which is a commodity that (i) brings significant revenues to Indian Railways, and (ii) is witnessing increasing imports. In this diagnostic study, we discuss the problems faced by Indian Railways and identify ways to increase its market share of coal movement between ports and the hinterland.

    DWT-Differential Analysis Optimization technique Used in the protection of Microgrid

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    This paper process DWT-differential analysis for optimal relay coordination issue for the microgrid. This solution works for grid-connected as well as the disconnected mode of operation. Coordination among relays of the microgrid is a complex part to handle, as the insertion of DG causes a bidirectional flow of current. Advanced protection methods involving DWT analysis of fault current can provide intelligent and smart ways of protection. Previous work has been applied with the differential algorithm on grid-connected and islanded mode, but one major deficiency is an increase in operating time of primary and secondary relay, which further decreases the reliability of Microgrid. The proposed system relies on DWT-differential Analysis based approach, which removes all unwanted noise and bandwidth from fault signal and differential analysis helps to select the best pair of a relay. The problem is formulated as a Non-linear programming constraint to minimize overall operating Relay time. The Scheme is tested with IEEE-9 bus system. The comparative analysis is carried out with two traditional methods, the result shows that it achieves a remarkable reduction in operating time in the primary and backup relay

    Study of Wavefront Tilt Variance with Various Telescope Apertures in Indoor Convective Turbulence

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    Turbulent atmosphere produces random wavefront tilt in the propagating laser beam and the dynamics of turbulence is largely depend on the receiving optics aperture size. In this paper, wavefront tilt variance is studied with various telescope aperture sizes in indoor convective turbulence. A simple experimental setup is described for simulating the near ground atmospheric turbulence by generating different strengths of convective turbulence in the laboratory. A laser beam is made to propagate through the turbulence subsequently induced wavefront tilt variances are experimentally measured and analyzed statistically. The wavefront tilt variance is used to estimate the temporal characteristics using Fourier transform by varying aperture sizes and turbulence strengths (i.e. ambient, weak and moderate). The Hurst exponent, the Fried parameter and the wavefront tilt frequencies for the different turbulence strengths are calculated. The power dependence of the wavefront tilt variance on the telescope aperture size is studied and a deviation from the classical D-1/3 dependence is reported

    Electroanatomic Mapping to determine Scar Regions in patients with Atrial Fibrillation

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    Left atrial voltage maps are routinely acquired during electroanatomic mapping in patients undergoing catheter ablation for atrial fibrillation. For patients, who have prior catheter ablation when they are in sinus rhythm, the voltage map can be used to identify low voltage areas using a threshold of 0.2 - 0.45 mV. However, such a voltage threshold for maps acquired during atrial fibrillation has not been well established. A prerequisite for defining a voltage threshold is to maximize the topologically matched low voltage areas between the electroanatomic mapping acquired during atrial fibrillation and sinus rhythm. This paper demonstrates a new technique to improve the sensitivity and specificity of the matched low voltage areas. This is achieved by computing omni-directional bipolar voltages and applying Gaussian Process Regression based interpolation to derive the atrial fibrillation map. The proposed method is evaluated on a test cohort of 7 male patients, and a total of 46,589 data points were included in analysis. The low voltage areas in the posterior left atrium and pulmonary vein junction are determined using the standard method and the proposed method. Overall, the proposed method showed patient-specific sensitivity and specificity in matching low voltage areas of 75.70% and 65.55% for a geometric mean of 70.69%. On average, there was an improvement of 3.00% in the geometric mean, 7.88% improvement in sensitivity, 0.30% improvement in specificity compared to the standard method. The results show that the proposed method is an improvement in matching low voltage areas. This may help develop the voltage threshold to better identify low voltage areas in the left atrium for patients in atrial fibrillation

    Electroanatomic Mapping to Determine Scar Regions in Patients with Atrial Fibrillation

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    Left atrial voltage maps are routinely acquired during electroanatomic mapping in patients undergoing catheter ablation for atrial fibrillation (AF). For patients, who have prior catheter ablation when they are in sinus rhythm (SR), the voltage map can be used to identify low voltage areas (LVAs) using a threshold of 0.2 - 0.45 mV. However, such a voltage threshold for maps acquired during AF has not been well established. A prerequisite for defining a voltage threshold is to maximize the topologically matched LVAs between the electroanatomic mapping acquired during AF and SR. This paper demonstrates a new technique to improve the sensitivity and specificity of the matched LVA. This is achieved by computing omni-directional bipolar voltages and applying Gaussian Process Regression based interpolation to derive the AF map. The proposed method is evaluated on a test cohort of 7 male patients, and a total of 46,589 data points were included in analysis. The LVAs in the posterior left atrium and pulmonary vein junction are determined using the standard method and the proposed method. Overall, the proposed method showed patient-specific sensitivity and specificity in matching LVAs of 75.70% and 65.55% for a geometric mean of 70.69%. On average, there was an improvement of 3.00% in the geometric mean, 7.88% improvement in sensitivity, 0.30% improvement in specificity compared to the standard method. The results show that the proposed method is an improvement in matching LVA. This may help develop the voltage threshold to better identify LVA in the left atrium for patients in AF

    Evaluation of analgesic activity of Emblica officinalis in albino rats

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    Background: Amla is one of the most often used herbs in indigenous medicine, whose all parts including fruit, seed, leaves, root, bark, and flowers are used in various Ayurvedic/Unani medicines. However, studies to establish analgesic potential of amla were limited, so the purpose of the present study was to evaluate analgesic activity of amla, if it possesses any.Methods: Albino rats were divided randomly in three groups of six rats each. Group 1 (control) received distilled water orally, Group 2 (test) received Emblica officinalis extract in dose of 600 mg/kg orally and Group 3 (standard) received Pentazocine in dose 10 mg/kg intraperitoneally.Results: Emblica officinalis extract did not produced statistically significant (p>0.05) analgesia when compared with the control group in hot plate latency, but produced a statistically significant reduction in 6% NaCl induced abdominal writhing (p<0.05). Conclusions: Since the plant extract significantly reduced the number of writhes in abdominal writhing model, but do not increase hot plate latency, the commercially available crude extract of Emblica officinalis exhibit analgesic activity involving peripheral mechanisms

    Computer Aided Clinical Trials for Implantable Cardiac Devices

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    In this paper we aim to answer the question, ``How can modeling and simulation of physiological systems be used to evaluate life-critical implantable medical devices?\u27\u27 Clinical trials for medical devices are becoming increasingly inefficient as they take several years to conduct, at very high cost and suffer from high rates of failure. For example, the Rhythm ID Goes Head-to-head Trial (RIGHT) sought to evaluate the performance of two arrhythmia discriminator algorithms for implantable cardioverter defibrillators, Vitality 2 vs. Medtronic, in terms of time-to-first inappropriate therapy, but concluded with results contrary to the initial hypothesis - after 5 years, 2,000+ patients and at considerable ethical and monetary cost. In this paper, we describe the design and performance of a computer-aided clinical trial (CACT) for Implantable Cardiac Devices where previous trial information, real patient data and closed-loop device models are effectively used to evaluate the trial with high confidence. We formulate the CACT in the context of RIGHT using a Bayesian statistical framework. We define a hierarchical model of the virtual cohort generated from a physiological model which captures the uncertainty in the parameters and allows for the systematic incorporation of information available at the design of the trial. With this formulation, the CACT estimates the inappropriate therapy rate of Vitality 2 compared to Medtronic as 33.22% vs 15.62% (
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