Thesis. 1977. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 40. / B.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaf 51. / by Kim Arthur Mosley. / M.S.

As NASA prepares to return humans to the moon and establish a long-term presence on the surface, technologies must be developed to access previously unvisited terrain regardless of the condition. Among these technologies is a guidance, navigation and control (GNC) system capable of safely and precisely delivering a spacecraft, whether manned or robotic, to a predetermined landing area. This thesis presents detailed research of both terrain-relative navigation using a terrain-scanning instrument and beacon-relative radiometric navigation using beacons in lunar orbit or on the surface of the moon. The models for these sensors are developed along with a baseline sensor suite that includes an altimeter, IMU, velocimeter, and star camera. Linear covariance analysis is used to rapidly perform the trade studies relevant to this problem and to provide the navigation performance data necessary to determine which navigation method is best suited to support a 100 m 3-σ navigation requirement for landing anytime and anywhere on the moon.

<p>Hjälpmedel är ofta en förutsättning för att personer med funktionshinder ska klara av sina</p><p>olika dagliga aktiviteter.Syftet med uppsatsen är att genomföra en jämförelse mellan Örebro län, Västmanland och Södermanland hur tillfredsställda brukarna är med sitt hjälpmedel och service.Resultatet visar</p><p>att majoriteten av brukare i de tre olika länen är tillfredställda med sitt hjälpmedel och service.</p><p>Det högsta medelvärdet visar att brukare i Örebro län var mest tillfredställda med variabeln</p><p>effektivitet och varaktighet, brukare i Västmanland var även de mest tillfredställda med</p><p>varaktighet. I Södermanland visade sig att brukare var mest tillfredsställda med variabeln</p><p>användbarhet.</p>

Hjälpmedel är ofta en förutsättning för att personer med funktionshinder ska klara av sina olika dagliga aktiviteter.Syftet med uppsatsen är att genomföra en jämförelse mellan Örebro län, Västmanland och Södermanland hur tillfredsställda brukarna är med sitt hjälpmedel och service.Resultatet visar att majoriteten av brukare i de tre olika länen är tillfredställda med sitt hjälpmedel och service. Det högsta medelvärdet visar att brukare i Örebro län var mest tillfredställda med variabeln effektivitet och varaktighet, brukare i Västmanland var även de mest tillfredställda med varaktighet. I Södermanland visade sig att brukare var mest tillfredsställda med variabeln användbarhet.

The objective of this work was to develop an analysis framework for the structural design of the Human-Powered Ornithopter (HPO). This framework was used in a kinematicaerostructural optimizer for apping-wing ight (Ornithia), as well as analytically to design the HPO, and focused on three goals. First was the development of an accurate and computationally inexpensive nite-element method, to be integrated with Ornithia, which would capture the geometric nonlinearity of the aerostructural interaction of the wing when subjected the large deformations in ight. Second was the assembly of a model by which the aircraft primary structure, the wing main spar especially, could be exactly characterized and designed. Third was the establishment of a process and toolbox for failure analysis which could be applied universally in the design of the HPO. The validation and tuning of these models involved extensive testing on prototype carbon ber composite components.

Powered wheelchairs offer a means of independent mobility for older adults who are unable to walk and cannot propel a manual wheelchair. Unfortunately, cognitively impaired older adults may be denied this means of independent mobility. There is concern that these adults are unable to drive a powered wheelchair safely or properly. Intelligent wheelchairs offer an approach to address this problem. This research outlines the development and evaluation of an Intelligent Wheelchair System (IWS) that is proposed to make powered wheelchairs safer and easier to use for cognitively impaired older adults. The IWS has anti-collision and navigation functions. Hardware results show a 1000% increase in computational speed compared to the previous IWS. Clinical results with dementia patients show that the IWS has the potential to increase safety by reducing frontal collisions, and by promoting safe completion of movement tasks. Usability of the system may be an issue.

The objective of this work was to develop an analysis framework for the structural design of the Human-Powered Ornithopter (HPO). This framework was used in a kinematicaerostructural optimizer for apping-wing ight (Ornithia), as well as analytically to design the HPO, and focused on three goals. First was the development of an accurate and computationally inexpensive nite-element method, to be integrated with Ornithia, which would capture the geometric nonlinearity of the aerostructural interaction of the wing when subjected the large deformations in ight. Second was the assembly of a model by which the aircraft primary structure, the wing main spar especially, could be exactly characterized and designed. Third was the establishment of a process and toolbox for failure analysis which could be applied universally in the design of the HPO. The validation and tuning of these models involved extensive testing on prototype carbon ber composite components.

Powered wheelchairs offer a means of independent mobility for older adults who are unable to walk and cannot propel a manual wheelchair. Unfortunately, cognitively impaired older adults may be denied this means of independent mobility. There is concern that these adults are unable to drive a powered wheelchair safely or properly. Intelligent wheelchairs offer an approach to address this problem. This research outlines the development and evaluation of an Intelligent Wheelchair System (IWS) that is proposed to make powered wheelchairs safer and easier to use for cognitively impaired older adults. The IWS has anti-collision and navigation functions. Hardware results show a 1000% increase in computational speed compared to the previous IWS. Clinical results with dementia patients show that the IWS has the potential to increase safety by reducing frontal collisions, and by promoting safe completion of movement tasks. Usability of the system may be an issue.

In this thesis we analyse X-ray data of accretion powered low mass and high mass X-ray binaries to understand the nature of their accretion mechanisms by searching for some clues of viscous time-scales of their accretion discs, if they have, in their low frequency power density spectra created from their long-term X-ray observations, or by doing pulse timing analysis with much shorter X-ray data to detect the effects of torque fluctuations caused by the accreting material on the pulsar. The low mass and high mass X-ray binaries we analysed have breaks in their power density spectra, which are attributed to the role of viscosity in the formation of accretion discs. Although, the time-scales corresponding to these break frequencies are smaller than the predictions of the Standard theory of accretion discs, the sources give consistent results among themselves by displaying the expected correlation between their break and orbital frequencies. The correlation curve of LMXBs implies thicker appearing accretion discs than those assumed by the theory. The dichotomy of the HMXBs on this curve points out the different origins of accretion that these sources may have, and offers a way to distinguish the stellar-wind fed systems from the Roche-lobe overflow systems. The timing and spectral analysis of Swift J1626.6-5156 reveal a correlation between the spin-up rate and the luminosity of the source implying that the pulsar is accretion-powered. This correlation together with the characteristics of the X-ray spectra enables us to estimate the magnetic field and the distance of the source. The AXP 1E 2259+586 does not display any signs of viscous time-scale in its low frequency power density spectra, and its pulse timing analysis gives a much smaller torque noise value than that expected from accretion powered pulsars. In addition, the analysis results presented in this thesis reveal magnetar-like glitches which differ than those of radio pulsars, due to the presence of the strong magnetic field of the pulsar. These results eliminate the possibility that the AXP is an accretion-powered pulsar.