52 research outputs found

    Computational rim illumination of dynamic subjects using aerial robots

    Get PDF
    Lighting plays a major role in photography. Professional photographers use elaborate installations to light their subjects and achieve sophisticated styles. However, lighting moving subjects performing dynamic tasks presents significant challenges and requires expensive manual intervention. A skilled additional assistant might be needed to reposition lights as the subject changes pose or moves, and the extra logistics significantly raises costs and time. The associated latencies as the assistant lights the subject, and the communication required from the photographer to achieve optimum lighting could mean missing a critical shot. We present a new approach to lighting dynamic subjects where an aerial robot equipped with a portable light source lights the subject to automatically achieve a desired lighting effect. We focus on rim lighting, a particularly challenging effect to achieve with dynamic subjects, and allow the photographer to specify a required rim width. Our algorithm processes the images from the photographer׳s camera and provides necessary motion commands to the aerial robot to achieve the desired rim width in the resulting photographs. With an indoor setup, we demonstrate a control approach that localizes the aerial robot with reference to the subject and tracks the subject to achieve the necessary motion. In addition to indoor experiments, we perform open-loop outdoor experiments in a realistic photo-shooting scenario to understand lighting ergonomics. Our proof-of-concept results demonstrate the utility of robots in computational lighting

    Controlled manipulation using autonomous aerial systems

    Get PDF
    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 134-135).The main focus of the thesis is to design and control Autonomous Aerial Systems, also referred to as Unmanned Aerial Vehicles (UAVs). UAVs are able to hover and navigate in space using the thrust forces generated by the propellers. One of the simplest such vehicles that is widely used is a Quadrotor. While UAVs have been predominantly used for "fly and sense" applications, very few investigations have focused on using them to perform manipulation by contact. The latter is challenging because of the dual goal of performing manipulation and maintaining stable flight. Because Quadrotors can quickly reach a location, their ability to manipulate can be impactful in many scenarios. While efficient flight control of Quadrotor has been an active research area, using Quadrotor to perform manipulation is novel and challenging. In this thesis, a range of Quadrotor designs and control strategies are proposed in order to carry out autonomous manipulation of objects. We first derive a dynamic model of the Quadrotor that accounts for the presence of contact, object dynamics and kinematics. To improve manipulation performance, a passive light-weight end-effector interface between the Quadrotor and the object is proposed. The complexity of the dynamics is systematically reduced by making certain assumptions. The resulting dynamic model is divided into nonlinear subsystems on the basis of their degrees of freedom, for each of which separate controllers are designed. An efficient docking approach is proposed that permits fast and aggressive docking, even at very high speeds. Because a single Quadrotor UAS is limited in manipulation capability, a multi Quadrotor cooperative manipulation scheme is proposed. Control strategies are proposed to deal with kinematic and parametric uncertainties. A manipulation scheme to open a door with unknown hinge location is proposed. A nonlinear adaptive controller is implemented to perform efficient tracking in the presence of parametric uncertainty. In order to improve robustness to accidental contacts, a novel flexible Quadrotor, denoted as ParaFlex, is designed. The advantages of ParaFlex over a rigid Quadrotor are demonstrated. A Simulation, Test and Validation Environment (STeVE) is developed to facilitate smooth and efficient transition from design process to simulation to experiments.by Manohar B. Srikanth.Ph.D

    Identification and authentication of Agnimantha plant species used in Ayurveda on the basis of anatomical and molecular phylogenetic analysis

    Get PDF
    Agnimantha plant species have been used in the Ayurvedic system of medicine for many years and is widely used as an ingredient in many ayurvedic formulations. However, the source for Agnimantha remained controversial as it is difficult to authenticate from various reports. Hence, the present study aims to identify and authenticate its original and substitute sources. As per the literature sources Clerodendrum phlomidis L.f., C. inerme (L.) Gaertn. and Premna serratifolia L. are considered Agnimantha species. The anatomy of the above mentioned species confirmed the presence of patches of up to 20 cells in the sclerenchyma of the root cortex, while in the absence of sclerenchyma of the stem cortex, abundant chambered crystals were also present in the bark of the stem and root in C. phlomidis as compared to C. inerme and P. serratifolia. Phylogenetic analysis using chloroplast (matK, trnH-psbA) and nuclear markers (ITS, rbcl) also indicates the close relation between C. inerme and P. serratifolia and hence places them both in the same clade, though C. phlomidis is closely related to the other species but placed in the adjacent clade. Hence, the study concludes that anatomical as well as molecular phylogenetic analysis reflect close relation between C. inerme and P. serratifolia. while a distant relation with C. phlomidis

    Medicinal plants used in the treatment of snakebite and scorpion sting by the tribesof Shahapur and Jawhar forest division

    Get PDF
    Many tribal communities living in the forest area deals with emergency cases of snakebite, scorpion sting by using traditional knowledge of medicinal plants. They possess Traditional and authentic information gained from their elders about the antidote for poisonous bites.  The present study was conducted in the tribal pockets of Shahapur and Jawhar forest division of Thane forest circle, Maharashtra. Data was collected by interviews with folk healers and informers by using specially design open and close-ended proforma. Collected data have been verified from the classical text of Ayurveda, books and available articles. This medico-ethno-botanical survey reveals the detail information on 27 plants belonging to 19 families. Total 17 and 10 claims have been reported for the treatment of snakebite and scorpion sting, respectively. Only 1 plant is claimed for veterinary use.  Tribal has been using flower, fruit, pod, root, stem, stem bark, leaf, etc. as an antidote in the form of fresh juice, powder for internal use and paste for local application. They also are administering medicine via Nasya (nasal administration) and Dhumapan (smoke). The observation generated by this article create scientific curiosity regarding further studies to evaluate the efficacy and develop antidote from medicinal plants based on tribal knowledg

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

    Get PDF
    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Acute otitis externa: Consensus definition, diagnostic criteria and core outcome set development.

    Get PDF
    OBJECTIVE: Evidence for the management of acute otitis externa (AOE) is limited, with unclear diagnostic criteria and variably reported outcome measures that may not reflect key stakeholder priorities. We aimed to develop 1) a definition, 2) diagnostic criteria and 3) a core outcome set (COS) for AOE. STUDY DESIGN: COS development according to Core Outcome Measures in Effectiveness Trials (COMET) methodology and parallel consensus selection of diagnostic criteria/definition. SETTING: Stakeholders from the United Kingdom. SUBJECTS AND METHODS: Comprehensive literature review identified candidate items for the COS, definition and diagnostic criteria. Nine individuals with past AOE generated further patient-centred candidate items. Candidate items were rated for importance by patient and professional (ENT doctors, general practitioners, microbiologists, nurses, audiologists) stakeholders in a three-round online Delphi exercise. Consensus items were grouped to form the COS, diagnostic criteria, and definition. RESULTS: Candidate COS items from patients (n = 28) and literature (n = 25) were deduplicated and amalgamated to a final candidate list (n = 46). Patients emphasised quality-of-life and the impact on daily activities/work. Via the Delphi process, stakeholders agreed on 31 candidate items. The final COS covered six outcomes: pain; disease severity; impact on quality-of-life and daily activities; patient satisfaction; treatment-related outcome; and microbiology. 14 candidate diagnostic criteria were identified, 8 reaching inclusion consensus. The final definition for AOE was 'diffuse inflammation of the ear canal skin of less than 6 weeks duration'. CONCLUSION: The development and adoption of a consensus definition, diagnostic criteria and a COS will help to standardise future research in AOE, facilitating meta-analysis. Consulting former patients throughout development highlighted deficiencies in the outcomes adopted previously, in particular concerning the impact of AOE on daily life

    Microbial fuel cells: From fundamentals to applications. A review

    Get PDF
    © 2017 The Author(s) In the past 10–15 years, the microbial fuel cell (MFC) technology has captured the attention of the scientific community for the possibility of transforming organic waste directly into electricity through microbially catalyzed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions. In this review, several aspects of the technology are considered. Firstly, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Secondly, the development of the concept of microbial fuel cell into a wider range of derivative technologies, called bioelectrochemical systems, is described introducing briefly microbial electrolysis cells, microbial desalination cells and microbial electrosynthesis cells. The focus is then shifted to electroactive biofilms and electron transfer mechanisms involved with solid electrodes. Carbonaceous and metallic anode materials are then introduced, followed by an explanation of the electro catalysis of the oxygen reduction reaction and its behavior in neutral media, from recent studies. Cathode catalysts based on carbonaceous, platinum-group metal and platinum-group-metal-free materials are presented, along with membrane materials with a view to future directions. Finally, microbial fuel cell practical implementation, through the utilization of energy output for practical applications, is described

    Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial

    Get PDF
    Background: Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events. Methods: The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627). Findings: Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92). Interpretation: These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention

    Effects of antiplatelet therapy after stroke due to intracerebral haemorrhage (RESTART): a randomised, open-label trial

    Get PDF
    Background: Antiplatelet therapy reduces the risk of major vascular events for people with occlusive vascular disease, although it might increase the risk of intracranial haemorrhage. Patients surviving the commonest subtype of intracranial haemorrhage, intracerebral haemorrhage, are at risk of both haemorrhagic and occlusive vascular events, but whether antiplatelet therapy can be used safely is unclear. We aimed to estimate the relative and absolute effects of antiplatelet therapy on recurrent intracerebral haemorrhage and whether this risk might exceed any reduction of occlusive vascular events. Methods: The REstart or STop Antithrombotics Randomised Trial (RESTART) was a prospective, randomised, open-label, blinded endpoint, parallel-group trial at 122 hospitals in the UK. We recruited adults (≥18 years) who were taking antithrombotic (antiplatelet or anticoagulant) therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage, discontinued antithrombotic therapy, and survived for 24 h. Computerised randomisation incorporating minimisation allocated participants (1:1) to start or avoid antiplatelet therapy. We followed participants for the primary outcome (recurrent symptomatic intracerebral haemorrhage) for up to 5 years. We analysed data from all randomised participants using Cox proportional hazards regression, adjusted for minimisation covariates. This trial is registered with ISRCTN (number ISRCTN71907627). Findings: Between May 22, 2013, and May 31, 2018, 537 participants were recruited a median of 76 days (IQR 29–146) after intracerebral haemorrhage onset: 268 were assigned to start and 269 (one withdrew) to avoid antiplatelet therapy. Participants were followed for a median of 2·0 years (IQR [1·0– 3·0]; completeness 99·3%). 12 (4%) of 268 participants allocated to antiplatelet therapy had recurrence of intracerebral haemorrhage compared with 23 (9%) of 268 participants allocated to avoid antiplatelet therapy (adjusted hazard ratio 0·51 [95% CI 0·25–1·03]; p=0·060). 18 (7%) participants allocated to antiplatelet therapy experienced major haemorrhagic events compared with 25 (9%) participants allocated to avoid antiplatelet therapy (0·71 [0·39–1·30]; p=0·27), and 39 [15%] participants allocated to antiplatelet therapy had major occlusive vascular events compared with 38 [14%] allocated to avoid antiplatelet therapy (1·02 [0·65–1·60]; p=0·92). Interpretation: These results exclude all but a very modest increase in the risk of recurrent intracerebral haemorrhage with antiplatelet therapy for patients on antithrombotic therapy for the prevention of occlusive vascular disease when they developed intracerebral haemorrhage. The risk of recurrent intracerebral haemorrhage is probably too small to exceed the established benefits of antiplatelet therapy for secondary prevention
    • …
    corecore