2,428 research outputs found

    Influence of structure and material research on advanced launch systems' weight, performance, and cost Summary report, May 25, 1965 - Jun. 30, 1967

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    Influence of structure and materials research on weight, performance, and cost of advanced launch vehicle system

    Solar rocket system concept analysis

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    The use of solar energy to heat propellant for application to Earth orbital/planetary propulsion systems is of interest because of its performance capabilities. The achievable specific impulse values are approximately double those delivered by a chemical rocket system, and the thrust is at least an order of magnitude greater than that produced by a mercury bombardment ion propulsion thruster. The primary advantage the solar heater thruster has over a mercury ion bombardment system is that its significantly higher thrust permits a marked reduction in mission trip time. The development of the space transportation system, offers the opportunity to utilize the full performance potential of the solar rocket. The requirements for transfer from low Earth orbit (LEO) to geosynchronous equatorial orbit (GEO) was examined as the return trip, GEO to LEO, both with and without payload. Payload weights considered ranged from 2000 to 100,000 pounds. The performance of the solar rocket was compared with that provided by LO2-LH2, N2O4-MMH, and mercury ion bombardment systems

    Asking the experts : developing and validating parental diaries to assess children's minor injuries

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    The methodological issues involved in parental reporting of events in children's everyday lives are discussed with reference to the development and validation of an incident diary, collecting concurrent data on minor injuries in a community study of children under eight years old. Eighty-two mothers participated in a comparison over nine days of daily telephone interviews and structured incident diaries. Telephone methods resulted in more missing data, and participants in both groups expressed a preference for the diary method. This diary was then validated on a sample of 56 preschool and school-aged children by comparing injury recording by a research health visitor with that of their mothers. Each failed to report some injuries, but there was good agreement overall, and in descriptive data on injuries reported by both. Parental diaries have the potential to provide rich data, of acceptable validity, on minor events in everyday life

    Development of programmed assistance in directing structures research

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    Programmed assistance in directing launch vehicle structures researc

    A Study into Detecting Anomalous Behaviours within HealthCare Infrastructures

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    The theft of medical data, which is intrinsically valuable, can lead to loss of patient privacy and trust. With increasing requirements for valuable and accurate information, patients need to be confident that their data is being stored safely and securely. However, medical devices are vulnerable to attacks from the digital domain, with many devices transmitting data unencrypted wirelessly to electronic patient record systems. As such, it is now becoming more necessary to visualise data patterns and trends in order identify erratic and anomalous data behaviours. In this paper, a system design for modelling data flow within healthcare infrastructures is presented. The system assists information security officers within healthcare organisations to improve the situational awareness of cyber security risks. In addition, a visualisation of TCP Socket Connections using real-world network data is put forward, in order to demonstrate the framework and present an analysis of potential risks

    Securing Health Care Information Systems using Visualisation Techniques

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    Health care information systems form the backbone of health care infrastructures and are increasingly reliant on medical devices to capture and transmit data. These devices, however, are vulnerable to attacks from the digital domain. The number of differing medical devices and information systems interacting with one another in new and increasingly less secure and disparate ways creates new challenges in information systems security. This work-in-progress paper presents a system design and methodology for modelling data interactions and data flow within the health care infrastructure. The system will increase situational awareness for users of information systems and promote stronger cyber security best practices and policies within this rapidly evolving landscape

    Decomposition of coarse woody debris in a long-term litter manipulation experiment: A focus on nutrient availability

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    The majority of above-ground carbon in tropical forests is stored in wood, which is returned to the atmosphere during decomposition of coarse woody debris. However, the factors controlling wood decomposition have not been experimentally manipulated over time scales comparable to the length of this process.We hypothesized that wood decomposition is limited by nutrient availability and tested this hypothesis in a long-term litter addition and removal experiment in a lowland tropical forest in Panama. Specifically, we quantified decomposition using a 15-year chronosequence of decaying boles, and measured respiration rates and nutrient limitation of wood decomposer communities.The long-term probability that a dead tree completely decomposed was decreased in plots where litter was removed, but did not differ between litter addition and control treatments. Similarly, respiration rates of wood decomposer communities were greater in control treatments relative to litter removal plots; litter addition treatments did not differ from either of the other treatments. Respiration rates increased in response to nutrient addition (nitrogen, phosphorus, and potassium) in the litter removal and addition treatments, but not in the controls.Established decreases in concentrations of soil nutrients in litter removal plots and increased respiration rates in response to nutrient addition suggest that reduced rates of wood decomposition after litter removal were caused by decreased nutrient availability. The effects of litter manipulations differed directionally from a previous short-term decomposition study in the same plots, and reduced rates of bole decomposition in litter removal plots did not emerge until after more than 6 years of decomposition. These differences suggest that litter-mediated effects on nutrient dynamics have complex interactions with decomposition over time

    A Machine Learning Framework for Securing Patient Records

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    This research concerns the detection of abnormal data usage and unauthorised access in large-scale critical networks, specifically healthcare infrastructures. The focus of this research is safeguarding Electronic Patient Record (EPR)systems in particular. Privacy is a primary concern amongst patients due to the rising adoption of EPR systems. There is growing evidence to suggest that patients may withhold information from healthcare providers due to lack of Trust in the security of EPRs. Yet, patient record data must be available to healthcare providers at the point of care. Roles within healthcare organisations are dynamic and relying on access control is not sufficient. Access to EPR is often heavily audited within healthcare infrastructures. However, this data is regularly left untouched in a data silo and only ever accessed on an ad hoc basis. In addition, external threats need to be identified, such as phishing or social engineering techniques to acquire a clinician’s logon credentials. Without proactive monitoring of audit records, data breaches may go undetected. This thesis proposes a novel machine learning framework using a density-based local outlier detection model, in addition to employing a Human-in-the-Loop Machine Learning (HILML) approach. The density-based outlier detection model enables patterns in EPR data to be extracted to profile user behaviour and device interactions in order to detect and visualise anomalous activities. Employing a HILML model ensures that inappropriate activity is investigated and the data analytics is continuously improving. The novel framework is able to detect 156 anomalous behaviours in an unlabelled dataset of 1,007,727 audit logs
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