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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Optimization of low thrust trajectories with terminal aerocapture /

Josselyn, Scott B. January 2003 (has links) (PDF)
Thesis (Aeronautical and Astronautical Engineer)--Naval Postgraduate School, June 2003. / Thesis advisor(s): I. Michael Ross, Steve Matousek. Includes bibliographical references (p. 149-150). Also available online.
42

Indirect optimization of interplanetary trajectories including spiral dynamics

Ranieri, Christopher Louis 28 August 2008 (has links)
Not available / text
43

GENERATION OF SUBOPTIMAL, CLOSED LOOP GUIDANCE FOR MINIMUM TIME AIRCRAFT TRAJECTORIES

Ishihara, Teruo, 1927- January 1969 (has links)
No description available.
44

Routes And Trajectories Based Dynamic Models For Traffic Prediction And Control

Wu, Fan January 2008 (has links)
Network traffic assignment/equilibrium models have been widely used for transportation planning. For traffic management, one is interested on how traffic patterns change dynamically since equilibrium cannot be reached instantaneously. This dissertation focuses on modeling short-term traffic patterns in a transportation network, and addresses these topics: (1) comparison of loading route flows versus link flows, (2) development of a mesoscopic model for loading route flows in a network, (3) estimation of route flows based on the mesoscopic model, and (4) optimizing traffic signal timings based on the estimated route flows.With regard to the first topic, many models propagate flows through a network using link flows and independent turning probabilities (ITP) at nodes. Chapter 2 describes the effects of the ITP assumption on the traffic patterns that occur based on route flow loading; this provides the motivation for using route flows in this research.Route trajectories are the spatial-temporal realizations of vehicle route flow demands. This dissertation proposes a mesoscopic simulation platform where route flows are propagated through the network and dynamic trajectories are computed. Under interrupted and uninterrupted flow conditions, route trajectories from the mesoscopic model are compared with ones from a microscopic model, the latter model being used to provide realistic data since real data at this level of detail is not currently available. Results from both models match well; the corresponding traffic patterns are very similar, both graphically and statistically.In chapter 5, a model is presented for estimating temporal route flow demands when real-time data is available. The model is formulated as a bi-level optimization problem where a least-square model is constructed at the upper level and the mesoscopic model is utilized at the lower level to relate flow demands and route trajectories. Based on real-time measurements, this model estimates dynamic route flows that are consistent with observed traffic patterns. Computational results using a micro-simulator for "real" data show that the model estimates well the route flows loaded in the micro-simulation model.Finally, in chapter 6, a traffic signal control optimizer is developed based on the mesoscopic model and a gradient search to optimize any given performance index such as average delay. A numerical example shows that the optimizer significantly improves the performance index and the approach may be used for on-line traffic signal control.
45

Deconstructing heterogeneity in adolescent sexual behaviour: a person-centered, developmental systems approach

Howard, Andrea Louise Dalton Unknown Date
No description available.
46

Fuel-optimal control and guidance for low-and medium-thrust orbit transfer

Goodson, Troy D. 08 1900 (has links)
No description available.
47

Deconstructing heterogeneity in adolescent sexual behaviour: a person-centered, developmental systems approach

Howard, Andrea Louise Dalton 11 1900 (has links)
This study examined heterogeneity in adolescents experimentation with partnered sexual behaviours. Participants were 88 high school students in Edmonton, Alberta (M age = 16.59, SD = .95). Students completed surveys online once per two months from December, 2008 through December, 2009. Surveys tracked students reports of seven sexual behaviours ranging in intimacy from holding hands to intercourse. Growth mixture models were used to sort students trajectories of sexual behaviours across months into latent classes based on similar profiles. The best-fitting model revealed three distinct classes, labeled inexperienced, experimenting, and experienced. Students classified as inexperienced primarily reported only lower-intimacy, non-genital sexual behaviours across months, and many reported no sexual behaviours. Students classified as experimenting and experienced reported similar levels of higher-intimacy sexual behaviours across months. Most experimenting students behaviours appeared to increase gradually from less to more intimate, whereas experienced students appeared to make abrupt transitions between lower- and higher-intimacy behaviours, month-to-month. Demographic, personal, peer, and family variables provided additional information that increased distinction among classes, and explained residual within-class heterogeneity. The probability of being classified as inexperienced was highest for students who were younger, reported fewer sexually experienced friends, and lower parent behavioural control. Students who reported higher parent behavioural control had the highest probability of being classified as experimenting. Relations between trajectories of sexual behaviour intimacy and risk factors (e.g., later pubertal timing, fewer problem behaviours) and protective-enhancing resources (e.g., higher psychosocial maturity, more intimate friendships) varied across classes. This study shows that there are multiple pathways of experimentation with sexual behaviour in adolescence. Results are consistent both with studies that emphasize the potential for sex in adolescence to be high-risk, and with studies and arguments that emphasize the potential for sex in adolescence to play an important preparatory role toward healthy adult sexual functioning. Theoretical arguments and discussion are guided by a person-centered, developmental systems approach.
48

Simultaneous localization and planning of cooperative air munitions via dynamic programming

Doucette, Emily A., Sinclair, Andrew J., January 2008 (has links) (PDF)
Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 36-37).
49

Parameter optimization of atmospheric skip trajectories for use in minimum fuel usage transfer orbits /

Martell, Craig Alan, January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 84-85). Also available via the Internet.
50

The reggeized-absorption model, and related matters

Moore, Robert John, January 1969 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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