• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 82
  • 48
  • 25
  • 13
  • 7
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 3
  • Tagged with
  • 227
  • 55
  • 54
  • 44
  • 44
  • 35
  • 35
  • 30
  • 27
  • 26
  • 25
  • 22
  • 22
  • 21
  • 20
  • 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.
61

Evaluation of advanced titanium matrix composites for 3rd generation reusable launch vehicles

Craft, Jason Scott 08 1900 (has links)
No description available.
62

CONTRAST: A conceptual reliability growth approach for comparison of launch vehicle architectures

Zwack, Mathew R. 12 January 2015 (has links)
In 2004, the NASA Astronaut Office produced a memo regarding the safety of next generation launch vehicles. The memo requested that these vehicles have a probability of loss of crew of at most 1 in 1000 flights, which represents nearly an order of magnitude decrease from current vehicles. The goal of LOC of 1 in 1000 flights has since been adopted by the launch vehicle design community as a requirement for the safety of future vehicles. This research addresses the gap between current vehicles and future goals by improving the capture of vehicle architecture effects on reliability and safety. Vehicle architecture pertains to the physical description of the vehicle itself, which includes manned or unmanned, number of stages, number of engines per stage, engine cycle types, redundancy, etc. During the operations phase of the vehicle life-cycle it is clear that each of these parameters will have an inherent effect on the reliability and safety of the vehicle. However, the vehicle architecture is typically determined during the early conceptual design phase when a baseline vehicle is selected. Unless a great amount of money and effort is spent, the architecture will remain relatively constant from conceptual design through operations. Due to the fact that the vehicle architecture is essentially “locked-in” during early design, it is expected that much of the vehicle's reliability potential will also be locked-in. This observation leads to the conclusion that improvement of vehicle reliability and safety in the area of vehicle architecture must be completed during early design. Evaluation of the effects of different architecture decisions must be performed prior to baseline selection, which helps to identify a vehicle that is most likely to meet the reliability and safety requirements when it reaches operations. Although methods exist for evaluating reliability and safety during early design, weaknesses exist when trying to evaluate all architecture effects simultaneously. The goal of this research was therefore to formulate and implement a method that is capable of quantitatively evaluating vehicle architecture effects on reliability and safety during early conceptual design. The ConcepTual Reliability Growth Approach for CompariSon of Launch Vehicle ArchiTectures (CONTRAST) was developed to meet this goal. Using the strengths of existing techniques a hybrid approach was developed, which utilizes a reliability growth projection to evaluate the vehicles. The growth models are first applied at the subsystem level and then a vehicle level projection is generated using a simple system level fault tree. This approach allows for the capture of all trades of interest at the subsystem level as well as many possible trades at the assembly level. The CONTRAST method is first tested on an example problem, which compares the method output to actual data from the Space Transportation System (STS). This example problem illustrates the ability of the CONTRAST method to capture reliability growth trends seen during vehicle operations. It also serves as a validation for the development of the reliability growth model assumptions for future applications of the method. The final chapter of the thesis applies the CONTRAST method to a relevant launch vehicle, the Space Launch System (SLS), which is currently under development. Within the application problem, the output of the method is first used to check that the primary research objective has been met. Next, the output is compared to a state-of-the-art tool in order to demonstrate the ability of the CONTRAST method to alleviate one of the primary consequences of using existing techniques. The final section within this chapter presents an analysis of the booster and upper stage block upgrade options for the SLS vehicle. A study of the upgrade options was carried out because the CONTRAST method is uniquely suited to look at the effects of such strategies. The results from the study of SLS block upgrades give interesting observations regarding the desired development order and upgrade strategy. Ultimately this application problem demonstrates the merits of applying the CONTRAST method during early design. This approach provides the designer with more information in regard to the expected reliability of the vehicle, which will ultimately enable the selection of a vehicle baseline that is most likely to meet the future requirements.
63

Reusable launch vehicles : crossroads between air and space law

Vissepó, Varlin January 2003 (has links)
Space technology is increasingly becoming part of our everyday life, businesses, governments and private entities rely heavily on satellite communications for their respective dealings and transactions. On the other hand, not all transactions or businesses can be done solely through telecommunications, we often need to get on an airplane and go somewhere else to do our respective businesses and if we are on vacation we definitely need to travel. The problem is that airplane travel, although fast, sometimes is not fast enough. Today's people want convenience and when they want something they usually want it fast, especially in business. Now, imagine yourself being able to get from Montreal to Sydney to close a business deal and be back home the same day or ordering a part from Tokyo to San Juan and have it delivered it the same day. It may seem like science fiction or something too far ahead in the future, but it is not. Currently, there are nations and private companies working on different prototypes that soon will be flying in our skies and above. These space transportation systems are the future of commercial transportation, but as every human activity, they will need regulation, in this thesis we will analyze the legal issues and aspects behind these future vehicles.
64

Design and analysis of rocket nozzle contours for launching pico-satellites /

Denton, Brandon Lee. January 2008 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (leaves 110-111).
65

Analysis of access-to-space missions utilizing on-board energy management and entropic analysis

Winter, Tyler Forrest, January 2008 (has links) (PDF)
Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 18, 2008) Includes bibliographical references (p. 127-129).
66

Do Proprietary Costs Deter Insider Trading?

January 2017 (has links)
abstract: Insider trading potentially reveals proprietary information, allowing rivals to compete more effectively against the insiders' firm. This paper examines whether proprietary costs are associated with insiders' trading decisions and the profitability of their trades. Using a variety of approaches to identify proprietary information risk, I find proprietary costs significantly deter insiders' trading activities. The deterrence effect is more pronounced when insider trading is likely to be more informative to rivals. Specifically, trades by top executives, non-routine trades, and trades at low complexity firms are curbed to a greater extent by proprietary costs. Examining the mechanisms of this deterrence effect, I find firms with higher proprietary costs are more likely to impose insider trading restrictions, and insiders' trading decisions are more sensitive to proprietary costs when they have higher share ownership of the company. These results suggest insiders reduce trading activities not only due to firm policies, but also due to incentive alignment. Finally, when insiders trade despite higher proprietary costs, they earn significantly higher abnormal profits from their purchase transactions. Overall, this study suggests product market considerations are an important factor associated with insiders' trading decisions and profitability of their trades. These findings are likely to be of interest to regulators and corporate boards in setting insider trading policies, and help investors make investment decisions using insider trading signals. / Dissertation/Thesis / Doctoral Dissertation Accountancy 2017
67

3D LOCALIZATION FOR LAUNCH VEHICLE USING COMBINED TOA AND AOA

Kwon, Soonho, Kim, Donghyun, Han, Jeongwoo, Kim, Dae-Oh, Hwang, Intae 10 1900 (has links)
Generally, a ground telemetry station for launch vehicle (LV) has tracking function only; therefore, position measurements depend on radar. Time of arrival (TOA) and angle of arrival (AOA) are typical location techniques for emitting targets. In this paper, we propose a Combined TOA and AOA localization method for LV using two ground stations. When transmitter (Tx) time is not known, it is necessary to make virtual onboard timer for TOA estimation. The virtual onboard timer generates time stamps of streaming frame according to data rate. First station which is located in space center has no tracking function. But it can generate the virtual onboard timer. Second station has tracking function, so it generates AOA information. By solving sphere equation(s) of TOA from at least one station and a line equation of AOA, target position in three-dimensions (3D) can be obtained. We confirm the localization performance by means of comparison with an on-board GPS of a real launch mission.
68

Skúsenosti z uvedenia značky Dettol na Slovensku a možnosti ich uplatnenia na českom trhu / Experience of Dettol brand launch in Slovakia and utilization of this experience for the Czech market

Kugla, Juraj January 2008 (has links)
The thesis deals with strategic brand management and brand launch. Specifically, the launch of antiseptic and disinfectant brand Dettol at Slovak market and supporting activities are being analyzed. Based on the outcomes of this analysis the strategic launch model for Dettol brand in the Czech Republic is proposed.
69

Zavedenie značky Vinea na český trh / Launch of "Vinea" Brand in the Czech Market

Šušnyák, Viktor January 2009 (has links)
Vinea is a traditional Slovak brand of grape-flavoured non-alcoholic beverage. It is owned by one of the largest producers of soft beverages in Central Europe - Kofola Group. Kofola is expected to launch the brand in the Czech market in the near future. This thesis deals with identification of Kofola's current position on the market and with formulation of an advisable launch strategy for Vinea. An online survey was used in order to acquire information necessary to formulate the strategy. The survey results can be found in the thesis. The theoretical part of the thesis contains a description of the most commonly used theoretical concepts related to situation analysis, strategies and brandbuilding.
70

Uvedení výrobku na trh, vyhodnocení jeho úspěšnosti / Analysis of introducing a new product into the Czech market

Skácelová, Martina January 2009 (has links)
Subject of the final thesis is a product launch into the Czech market by company Pfanner, spol. s r.o. The main task is to analyse this launch of product called Kouzelné brčko by means of survey, revenue and cost analysis and defined goals of the company. Also consumer behavior and marketing mix was analyzed and evaluated.

Page generated in 0.0177 seconds