A cost model for testing unmanned and autonomous systems of systems

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2011.Vita. Page 124 blank. Cataloged from PDF version of thesis.Includes bibliographical references (p. 113-114).The evolutionary nature of Unmanned and Autonomous Systems of Systems (UASoS) acquisition needs to be matched by equally evolutionary test capabilities in the future. There is currently no standard method to determine what is required to make programs safe for deployment, nor is there the ability to make effective contingency plans should testing requirements change. Spending too much effort designing goals when causal understandings are still in flux is inefficient. As such, policy making and enforcing policies on the deployment of UASoS becomes very problematic. Testing is required especially for UASoS to identify risk, improve capabilities and minimize unpleasant surprises. It needs to be effective and focused, determining the issues and working towards ensuring the risks of the UASoS are known. It is important to have adequate feedback loops, a culture of information sharing and learning from best practices, as well as the development of metrics and/or performance indicators that adequately reflect the effectiveness of the test process. This thesis describes a model that is part of a larger Prescriptive and Adaptive Testing Framework (PATFrame), which uses knowledge acquisition to minimize risk through a decision support system. This work presents the cost and risk considerations for UASoS T&E and provides the preliminary parameters to conduct trade-off analyses for T&E. It also provides guidance on how the DoD can adopt such tools to transform the DoD T&E enterprise. The model is a combination of information collected from various normative and descriptive views of testing based on literature review, surveys, and interviews with members of the Department of Defense (DoD) T&E community A cost estimation model can have significant impacts on how the DoD currently does testing and would help maximize the use of the resources available. It is a model based method for calculating effort for test and evaluation and forms a baseline for strategic decision making in DoD acquisition programs. The intent is to predict within a certain probability that a test program can be completed within a certain budget given the assumptions used in characterizing the UASoS and the T&E process.by Indira D. Deonandan.S.M.in Technology and PolicyS.M

Feasibility of elastomeric composites as alternative materials for marine applications: A compendious review on their properties and opportunities

© IMechE 2022. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1177/14750902221095321The term elastomer is a curtailment of two words, which are elastic and polymers. Accordingly, elastomers are polymer materials with elasticity. The significant challenges hindering the development of materials for naval applications, similar to other engineering sectors, include achieving a competitive light elastomeric structure. Marine structures are susceptible to various damage responses due to various loads throughout their service life. Being flexible, elastomer has a low modulus of elasticity, exhibits higher values of failure strain and yield strength. In these regards, elastomers are attractive materials for applications that require elasticity because they offer substantial advantages compared to traditional materials. However, the low fire resistance of these elastomeric materials jeopardizes their use in some critical applications. As a result, elastomeric blends and composites containing flame retardant (FR) additives are commonly used. On the other hand, elastomers possess (i) high strength-to-weight ratio, (ii) excellent impact properties, (iii) low infrared, magnetic, and radar signatures, (iv) excellent durability, and (v) high resilience to extreme loads. Hence, the scope of this study focuses on review and awareness regarding the feasibility of marine applications of elastomers/ elastomeric composites, their current scientific and technological drawbacks, and future outlooks or prospects to support several applications in the marine industry.Peer reviewe

Consensus statement from the International Consensus Meeting on the Role of Decompressive Craniectomy in the Management of Traumatic Brain Injury

Abstract: Background: Two randomised trials assessing the effectiveness of decompressive craniectomy (DC) following traumatic brain injury (TBI) were published in recent years: DECRA in 2011 and RESCUEicp in 2016. As the results have generated debate amongst clinicians and researchers working in the field of TBI worldwide, it was felt necessary to provide general guidance on the use of DC following TBI and identify areas of ongoing uncertainty via a consensus-based approach. Methods: The International Consensus Meeting on the Role of Decompressive Craniectomy in the Management of Traumatic Brain Injury took place in Cambridge, UK, on the 28th and 29th September 2017. The meeting was jointly organised by the World Federation of Neurosurgical Societies (WFNS), AO/Global Neuro and the NIHR Global Health Research Group on Neurotrauma. Discussions and voting were organised around six pre-specified themes: (1) primary DC for mass lesions, (2) secondary DC for intracranial hypertension, (3) peri-operative care, (4) surgical technique, (5) cranial reconstruction and (6) DC in low- and middle-income countries. Results: The invited participants discussed existing published evidence and proposed consensus statements. Statements required an agreement threshold of more than 70% by blinded voting for approval. Conclusions: In this manuscript, we present the final consensus-based recommendations. We have also identified areas of uncertainty, where further research is required, including the role of primary DC, the role of hinge craniotomy and the optimal timing and material for skull reconstruction

LETTERS TO EDITOR - Atlanto-Occipital Dislocation in Rickets : Letter to Editor

A three year old boy fell down while playing and could not move any of his four limbs. There was no loss of consciousness or no respiratory difficulty. He had no sphincter disturbances

CASE REPORT - Tuberculoma en Plaque : A Case Report

A 14 year old girl presented with a 6-month history of headaches and visual blurring. CT showed a right tentorial enhancing lesion. Angiogram showed no enhancement. Histopathological examination of the excised material was consistent with tuberculoma. The presentation of such unusual intracranial tuberculoma is reported and the literature reviewed on the subject

Case Report - Tuberculous osteitis of clivus

Tuberculous osteitis of clivus is rare. Its diagnosis is difficult because of the rarity of the site and the non-specific nature of the disease. Management consists of confirmation of diagnosis by biopsy and chemotherapy with anti-tubercular drugs. Meningitis may complicate the clinical course, increase morbidity and mortality

Thoracic cord compression due to ossified hypertrophied ligamentum flavum

Ossified ligamentum flavum is increasingly appreciated as an important cause of thoracic myeloradiculopathy. Fifteen patients with age ranging from 30-61 years were studied. Fourteen presented with spastic paraparesis, and radiculopathy was the only complaint in one patient. Routine skiagrams and myelograms showed non-specific changes. Baseline CT and CT myelogram, however, documented the ossification of ligamentum flavum comprehensively. MRI was done in three patients. Multiple levels of the disease were seen in two cases. Four patients had ossified posterior longitudinal ligament. Thickened ligamentum flavum should be considered as an important cause of thoracic cord compression

Anomalous behaviour of very low frequency signals during the earthquake events

333-339The seismo-ionospheric coupling has been extensively studied in the recent years adopting various ionospheric parameters, like the critical frequency of F2 and Es layers and total electron content (TEC). There have been reports of seismic signatures in the amplitude and phase of the very low frequency (VLF) waves when an intense earthquake occurs near the propagation path. In the present paper, the amplitude of VLF waves transmitted from GQD (UK), GBZ (UK) and TBB (Turkey) received in South France during the period 2010-2013 has been studied for the precursory effect of earthquakes on the morning and evening terminator timings (TT). Six earthquake events of magnitude greater than 5 have been considered. The results of the present study show that the evening terminator undergoes many fluctuations during the pre-earthquake period of 5-15 days. But the pre-earthquake fluctuations in the morning terminator are predominant for three events, namely 8 March 2010, 11 April 2010 and 22 May 2012. The VLF day (time between morning terminator and evening terminator) is observed to be longer in the pre-earthquake period for three events