1,004 research outputs found

    The Schwinger SU(3) construction - I: Multiplicity problem and relation to induced representations

    Full text link
    The Schwinger oscillator operator representation of SU(3) is analysed with particular reference to the problem of multiplicity of irreducible representations. It is shown that with the use of an Sp(2,R)Sp(2,R) unitary representation commuting with the SU(3) representation, the infinity of occurrences of each SU(3) irreducible representation can be handled in complete detail. A natural `generating representation' for SU(3), containing each irreducible representation exactly once, is identified within a subspace of the Schwinger construction; and this is shown to be equivalent to an induced representation of SU(3).Comment: Latex, 25 page

    PHOTOVOLTAIC BASED FLEXIBLE MICROGRID SYSTEM USING FUZZY LOGIC

    Get PDF
    This paper presents a flexible ac distribution system device for microgrid applications. The device aims to improve the power quality and reliability of the overall power distribution system that the microgrid is connected to. The control design employs a new model predictive control algorithm which allows faster computational time for large power systems by optimizing the steady-state and the transient control problems separately. In this paper Fuzzy logic controlling technique has been introduced to extract the harmonic spectra of the grid voltage and the load currents in the microgrid. The design concept is verified through different test case scenarios to demonstrate the capability of the proposed device and the Matlab/Simulink results are Presented

    Observational evidence for remote forcing of the West India coastal current

    Get PDF
    Circulation in the north Indian Ocean is influenced by both local and remote wind forcing. So far, however, determining the contribution of these two forcing mechanisms at a location has been possible only in numerical experiments. Here we separate remote and local forcing in observations. Using field measurements (current, sea level, and wind) for a month during March-April 2003 off Goa in the near-coast regime of the West India Coastal Current (WICC), we show that the current was driven by local winds only at periods less than ∼10 days, with remote forcing contributing at longer periods. The high-passed (HP; period less than ~10 days) component of the along-shore current was strongly correlated with the HP component of the along-shore wind, the current lagging the wind by half a day. The low-passed (LP) components of the wind and current were not correlated: the former was unidirectional, but the latter reversed during the period of observation. The relationship between the HP wind and current was used to estimate the locally forced LP current, permitting an estimate of the remote current, the LP residual. This separation of locally forced and remotely forced currents showed that remote forcing contributed as much as local forcing to the WICC. The local current behaved like a classical eastern boundary current forced by local winds. The reversal in the remote current was due to winds 700 km farther south along the coast; frictional damping had an impact only at periods less than 10 days, there being no remotely forced HP current

    Control Barrier Functions in UGVs for Kinematic Obstacle Avoidance: A Collision Cone Approach

    Full text link
    In this paper, we propose a new class of Control Barrier Functions (CBFs) for Unmanned Ground Vehicles (UGVs) that help avoid collisions with kinematic (non-zero velocity) obstacles. While the current forms of CBFs have been successful in guaranteeing safety/collision avoidance with static obstacles, extensions for the dynamic case with torque/acceleration-controlled unicycle and bicycle models have seen limited success. Moreover, with these nonholonomic UGV models, applications of existing CBFs have been conservative in terms of control, i.e., steering/thrust control has not been possible under certain common scenarios. Drawing inspiration from the classical use of collision cones for obstacle avoidance in path planning, we introduce its novel CBF formulation with theoretical guarantees on safety for both the unicycle and bicycle models. The main idea is to ensure that the velocity of the obstacle w.r.t. the vehicle is always pointing away from the vehicle. Accordingly, we construct a constraint that ensures that the velocity vector always avoids a cone of vectors pointing at the vehicle. The efficacy of this new control methodology is experimentally verified on the Copernicus mobile robot. We further extend it to the bicycle model and demonstrate collision avoidance under various scenarios in the CARLA simulator.Comment: Submitted to 2023 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). 8 pages, 8 figures, For supplement video follow https://youtu.be/4qWYaWEPduM. The first and second authors have contributed equall

    Over-expression of 60s ribosomal L23a is associated with cellular proliferation in SAG resistant clinical isolates of Leishmania donovani

    Get PDF
    Background: Sodium antimony gluconate (SAG) unresponsiveness of Leishmania donovani (Ld) had effectively compromised the chemotherapeutic potential of SAG. 60s ribosomal L23a (60sRL23a), identified as one of the over-expressed protein in different resistant strains of L. donovani as observed with differential proteomics studies indicates towards its possible involvement in SAG resistance in L. donovani. In the present study 60sRL23a has been characterized for its probable association with SAG resistance mechanism. Methodology and principal findings: The expression profile of 60s ribosomal L23a (60sRL23a) was checked in different SAG resistant as well as sensitive strains of L. donovani clinical isolates by real-time PCR and western blotting and was found to be up-regulated in resistant strains. Ld60sRL23a was cloned, expressed in E.coli system and purified for raising antibody in swiss mice and was observed to have cytosolic localization in L.donovani. 60sRL23a was further over-expressed in sensitive strain of L. donovani to check its sensitivity profile against SAG (Sb V and III) and was found to be altered towards the resistant mode. Conclusion/Significance: This study reports for the first time that the over expression of 60sRL23a in SAG sensitive parasite decreases the sensitivity of the parasite towards SAG, miltefosine and paramomycin. Growth curve of the tranfectants further indicated the proliferative potential of 60sRL23a assisting the parasite survival and reaffirming the extra ribosomal role of 60sRL23a. The study thus indicates towards the role of the protein in lowering and redistributing the drug pressure by increased proliferation of parasites and warrants further longitudinal study to understand the underlying mechanism

    The Great Tsunami of 26 December 2004: A description based on tide-gauge data from the Indian subcontinent and surrounding areas

    Get PDF
    The Great Tsunami of 26 December 2004 is described using data from seven tide gauges in India and others from surrounding areas in the Indian Ocean. The tsunami struck the Indian east coast around 0330 UTC. The amplitude was 2 m above the tide at Chennai, Paradip, and Colombo. The east coast of India (and of Sri Lanka) was hit shortly after high tide; Tuticorin and Colombo, however, were hit shortly after low tide. The tsunami wave propagated northward along the Indian west coast. All these gauges are to the west of the earthquake zone and the detided sea levels show first a rise in sea level with the arrival of the tsunami, and then a sharp decrease. Spectral and wavelet analysis of the detided series show that the maximum amplitude was at a period of 35-45 minutes, with another maximum around 20 minutes. Along the Indian east coast, however, there is another broad peak between 1-2 hours within the first few hours after the first tsunami wave

    Traumatic acute posterior fossa subdural hematoma: A case report and review of literature

    Get PDF
    Traumatic subdural hematomas of the posterior fossa are rare but dangerous neurosurgical emergencies that require prompt diagnosis and management to avoid the uniformly poor outcome. We present a case of a teenager with severe TBI and acute subdural hematoma of the posterior fossa that deteriorated rapidly before surgery but eventually made a good recovery. We also the review the literature concerning traumatic posterior fossa subdural hematomas [PFSDH]

    Traumatic Acute Posterior Fossa Subdural Hematoma -A case report and review of literature

    Get PDF
    Abstract Traumatic subdural hematomas of the posterior fossa are rare but dangerous neurosurgical emergencies that require prompt diagnosis and management to avoid the uniformly poor outcome. We present a case of a teenager with severe TBI and acute subdural hematoma of the posterior fossa that deteriorated rapidly before surgery but eventually made a good recovery. We also the review the literature concerning traumatic posterior fossa subdural hematomas [PFSDH]

    Inner wellbeing: concept and validation of a new approach to subjective perceptions of wellbeing-India

    Get PDF
    © The Author(s) 2013. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This paper describes the conceptual development of a multi-domain, psychosocial model of 'Inner Wellbeing' (IWB) and assesses the construct validity of the scale designed to measure it. IWB expresses what people think and feel they are able to be and do. Drawing together scholarship in wellbeing and international development it is grounded in field research in marginalised, rural communities in the global South. Results from research in India at two points in time (2011 and 2013) are reported. At Time 1 (n = 287), we were unable to confirm an eight-factor, correlated model as distinct yet interrelated domains. However, at Time 2 (n = 335), we were able to confirm a revised, seven-factor correlated model with economic confidence, agency and participation, social connections, close relationships, physical and mental health, competence and self-worth, and values and meaning (five items per domain) as distinct yet interrelated domains. In particular, at Time 2, a seven-factor, correlated model provided a significantly better fit to the data than did a one-factor model.This work is supported by the Economic and Social Research Council/Department for International Development Joint Scheme for Research on International Development (Poverty Alleviation) grant number RES-167-25-0507 ES/H033769/1. Special thanks are due to Chaupal and Gangaram Paikra, Pritam Das, Usha Kujur, Kanti Minjh, Susanna Siddiqui, and Dinesh Tirkey
    corecore