85 research outputs found
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New safety model for the commercial human spaceflight industry
The aviation and space domains have safety guidelines and recommended practices for Design Organisations (DOs) and Operators alike. In terms of Aerospace DOs there are certification criteria to meet and to demonstrate compliance there are Advisory Circulars or Acceptable Means of Compliance to follow. Additionally there are guidelines such as Aerospace Recommended Practices (ARP), Military Standards (MIL-STD 882 series) and System Safety Handbooks to follow in order to identify and manage failure conditions. In terms of Operators there are FAA guidelines and a useful ARP that details many tools and techniques in understanding Operator Safety Risks. However there is currently no methodology for linking the DO and Operator safety efforts. In the space domain NASA have provided safety standards and guidelines to follow and also within Europe there are European Co-operation of Space Standardization (ECSS) to follow. Within the emerging Commercial Human Spaceflight Industry, the FAA’s Office of Commercial Space Transportation has provided hazard analysis guidelines. However all of these space domain safety documents are based on the existing aerospace methodology and once again, there is no link between the DO and Operator’s safety effort.
This paper addresses the problematic issue and presents a coherent methodology of joining up the System Safety effort of the DOs to the Operator Safety Risk Management such that a ‘Total System’ approach is adopted. Part of the rationale is that the correct mitigation (control) can be applied within the correct place in the accident sequence. Also this contiguous approach ensures that the Operator is fully aware of the safety risks (at the accident level) and therefore has an appreciation of the Total System Risk.
The authors of this paper contend that it is better practice to have a fully integrated safety model as opposed to disparate requirements or guidelines. Our methodology is firstly to review ‘best practice’ approaches from the aviation and space industries, and then to integrate these approaches into a contiguous safety model for the commercial human spaceflight industry
A knowledge capturing and sharing framework for improving the testing processes in global product development using storytelling and video sharing
In today’s global marketplace employee knowledge is seen as a crucial asset for organisations, which enables them to gain a sustainable competitive edge over competitors. Much of the knowledge generated during New Product Development (NPD) and testing can be categorised as tacit, developed from employees’ personal experiences and perceptions during Product Development (PD) projects; this makes it more difficult to capture and document for future sharing and re-use. The advent of Social Media in the last decade has changed the way many employees and global organisations communicate and interact with one another, providing a medium for knowledge to be transferred across the World Wide Web in a less formal manner. This research explores whether storytelling and video sharing functionality, embedded into a corporate social media site, is capable of facilitating the capture and sharing of employee knowledge during the PD cycle, providing user feedback on the developed knowledge capture and sharing methodology. It also presents a knowledge framework that is directly driven by the knowledge user, providing both knowledge direction and content
Mutational spectrum of the succinate semialdehyde dehydrogenase (ALDH5A1) gene and functional analysis of 27 novel disease-causing mutations in patients with SSADH deficiency
Succinate semialdehyde dehydrogenase (SSADH; ALlDH5A1) deficiency, a rare metabolic disorder that disrupts the normal degradation of GABA, gives rise to a highly heterogeneous neurological phenotype ranging from mild to very severe. The nature of the mutation has so far been reported in patients from six families world wide and eight different mutations were described. Here we report the mutational spectrum in 48 additional unrelated families of different geographic origin. We detected 27 novel mutations at the cDNA level, of which 26 could be attributed to changes at the genomic level. Furthermore, six mutations were detected that did not strongly affect SSADH activity when expressed in HEK 293 cells and are considered nonpathogenic allelic variants. Twenty of the mutations were only found in one family. The spectrum of disease-causing mutations from all patients sequenced thus far consists of 25 point mutations, four small insertions, and five small deletions. Seven of these mutations affect splice junctions, seven are nonsense mutations, and 12 are missense mutations. Although there were no mutational hotspots or prevalent mutations responsible for a significant number of cases, 14 out of 37 (38%) of the missense alleles were present in exon 4 or 5. With one exception, the missense mutations we consider to be causative of SSADH deficiency reduced the SSADH activity to less than 5% of the normal activity in our in vitro expression system. This indicates that residual expression is not likely to be an important factor contributing to the large phenotypic differences observed among different families and even among siblings, suggesting that other modifying factors are of great importance in disease pathology. (C) 2003 Wiley,Liss, Inc
High accuracy mobile robot positioning using external large volume metrology instruments
A method of accurately controlling the position of a mobile robot using an external large volume metrology (LVM) instrument is presented in this article. By utilising an LVM instrument such as a laser tracker or indoor GPS (iGPS) in mobile robot navigation, many of the most difficult problems in mobile robot navigation can be simplified or avoided. Using the real-time position information from the laser tracker, a very simple navigation algorithm, and a low cost robot, 5mm repeatability was achieved over a volume of 30m radius. A surface digitisation scan of a wind turbine blade section was also demonstrated, illustrating possible applications of the method for manufacturing processes. Further, iGPS guidance of a small KUKA omni-directional robot has been demonstrated, and a full scale prototype system is being developed in cooperation with KUKA Robotics, UK. © 2011 Taylor & Francis
Rapid machine tool verification
This paper describes work carried out to develop methods of verifying that machine tools are capable of machining parts to within specification, immediately before carrying out critical material removal operations, and with negligible impact on process times. A review of machine tool calibration and verification technologies identified that current techniques were not suitable due to requirements for significant time and skilled human intervention. A 'solution toolkit' is presented consisting of a selection circular tests and artefact probing which are able to rapidly verify the kinematic errors and in some cases also dynamic errors for different types of machine tool, as well as supplementary methods for tool and spindle error detection. A novel artefact probing process is introduced which simplifies data processing so that the process can be readily automated using only the native machine tool controller. Laboratory testing and industrial case studies are described which demonstrate the effectiveness of this approach
Verification of the indoor GPS system, by comparison with calibrated coordinates and by angular reference
This paper details work carried out to verify the dimensional measurement performance of the Indoor GPS (iGPS) system; a network of Rotary-Laser Automatic Theodolites (R-LATs). Initially tests were carried out to determine the angular uncertainties on an individual R-LAT transmitter-receiver pair. A method is presented of determining the uncertainty of dimensional measurement for a three dimensional coordinate measurement machine. An experimental procedure was developed to compare three dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with the multilateration technique employed to establish three dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. The method was found to be practical and able to establish that the expanded uncertainty of the basic iGPS system was approximately 1 mm at a 95% confidence level. Further tests carried out on a highly optimized version of the iGPS system have shown that the coordinate uncertainty can be reduced to 0.25 mm at a 95% confidence level
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