Zobrazeno 1 - 10
of 23
pro vyhledávání: '"Yohannes Ketema"'
Autor:
Yohannes Ketema
Publikováno v:
Journal of Guidance, Control, and Dynamics. 45:2318-2331
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0d08175eac2a1af5a3e605adc7c0f91e
https://doi.org/10.2514/1.g006574
https://doi.org/10.2514/1.g006574
Autor:
Yingjie Hu, Yohannes Ketema, Robert McGovern, James Jean, Alec Jonason, Demoz Gebre-Egziabher, Jacob Hanson
Publikováno v:
The International Technical Meeting of the The Institute of Navigation.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c6b96f33179fdf45a103d9a63ba2c5f5
https://doi.org/10.33012/2022.18187
https://doi.org/10.33012/2022.18187
Autor:
Yohannes Ketema
Publikováno v:
Acta Astronautica. 136:64-79
A method for asteroid deflection that makes use of a spacecraft moving back and forth on a segment of an appropriate Keplerian orbit about the asteroid is described and evaluated. It is shown that, on average, the spacecraft describing such a traject
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d523158c9904e0fffe39e5f2e96df870
https://doi.org/10.1016/j.actaastro.2017.03.004
https://doi.org/10.1016/j.actaastro.2017.03.004
Autor:
Demoz Gebre-Egziabher, Yohannes Ketema
Publikováno v:
Journal of Biomechanical Engineering. 138
A method for estimating gait parameters (shank, thigh, and stance leg angles) from a single, in situ, scalar acceleration measurement is presented. A method for minimizing the impact of errors due to unpredictable variations in muscle actuation and a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::80779f4b8815a668195ccc135178cdf1
https://doi.org/10.1115/1.4032047
https://doi.org/10.1115/1.4032047
Autor:
Yohannes Ketema, Yiyuan Zhao
Publikováno v:
Journal of Aircraft. 47:1460-1463
M ICRO aerial vehicles (MAVs) are small aerial vehicles, generallywith dimensions on the order of 1 ft (or 0.3m). Their small sizes often imply that their flight speeds are also small, roughly on the order of 20–60 km=h. MAVs come in a wide variety
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::51278cdfcc431f17eeac4bca9fd997cb
https://doi.org/10.2514/1.c000247
https://doi.org/10.2514/1.c000247
Autor:
Yohannes Ketema, Yiyuan Zhao
Publikováno v:
Journal of Guidance, Control, and Dynamics. 33:1020-1024
CD0 = zero-lift drag coefficient CL, CD = lift and drag coefficients D = aerodynamic drag Emax = maximum lift-to-drag ratio or aerodynamic efficiency g = gravitational acceleration I = performance index K = induced drag factor L = aerodynamic lift m
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::4c563ca506b45f2146e3810fdbfe4a97
https://doi.org/10.2514/1.44779
https://doi.org/10.2514/1.44779
Autor:
Yohannes Ketema
Publikováno v:
Journal of Guidance, Control, and Dynamics. 32:1508-1518
A first-order approximation of optimal two-burn transfers between satellite orbits within a formation is presented and discussed. The orbital transfer problem is based on the well-known fact that, to first order, such orbits are elliptic, with center
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::953a624052efa884cf36d78ceb3614e8
https://doi.org/10.2514/1.42847
https://doi.org/10.2514/1.42847
Autor:
Roger Fosdick, Yohannes Ketema
Publikováno v:
Journal of Intelligent Material Systems and Structures. 20:1587-1601
We study the effects of heat transfer on the vibration damping properties of a shape memory wire. We assume that the pseudoelastic behavior of the shape memory wire is due to a stress-induced phase transformation which is governed by a temperature-de
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5cac0e8e9c55151605948ffac5bb71cf
https://doi.org/10.1177/1045389x09102564
https://doi.org/10.1177/1045389x09102564
Autor:
Yohannes Ketema
Publikováno v:
The Journal of the Astronautical Sciences. 53:373-389
A method for the determination of accurate analytical expressions for the time dependence of the relative motion of two noninteracting masses under the gravitational influence of a spherical primary mass is presented and discussed. The case of the el
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0a79f46c9bb4307c280bc146ababebc7
https://doi.org/10.1007/bf03546359
https://doi.org/10.1007/bf03546359
Autor:
Yohannes Ketema
Publikováno v:
Journal of Applied Mechanics. 70:757-761
An oscillator where the restoring force is furnished by a viscoelastic bar and therefore depends on the history of the motion is considered. The history-dependent force is characterized by a relaxation modulus and a relaxation time. Assuming that the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5d02a669a978e92ac7ccb9a46e7088c7
https://doi.org/10.1115/1.1607355
https://doi.org/10.1115/1.1607355