Thesis (M.S.), University of Central Oklahoma, 2009. / Includes bibliographical references (leaves 31-38).

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 122-132). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 74-87). Available also in a digital version from Dissertation Abstracts.

Thesis (M. Sc.)--Carleton University, 1993. / Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Asim Bej, Gene Hines, Douglas Watson, Douglas Weigent. Description based on contents viewed Oct. 2, 2008; title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

This PhD thesis describes parachute rescue systems for small planes and focuses on their functionality in the border areas of the flight envelope, especially at very low altitudes and low airspeeds of flight (fall). For extending the functionality of the rescue system in extreme areas of usability envelope, was founded an innovative dividable parachute slider, which works normally at high speed, but at the low airspeeds does not limit the opening time of the canopy. Structural design of this slider is the subject of a new patent application “Parachute opening speed regulation device”, filed with Industrial property Office in Prague on August 14, 2014 under number 2014-543 PV. The PhD thesis further contains computational principle of circular parachute opening and the structural design. For verification of the dividable slider functionality, a parachute model has been constructed and subjected to a series of drop tests. The main benefit of the PhD thesis is extending the usability of rescue system into its statistically most frequent use, i.e. into low altitudes and low airspeeds of flight (fall).

Some agent-based systems depend on eliciting ratings from the user. However, the user’s willingness to provide ratings is limited due to requisite demands of attention and effort. From a human-centered view, we redefine providing ratings as expressing interest. We develop a new interface component for parameter setting, the In-Context Slider, which reduces physical effort and demand on attention by using fluid mouse gestures and in-context interaction. We hypothesize that such an interface should make interest expression easier for the user. We evaluated the In-Context Slider as an interest expression component compared with a more typical interface. Participants performed faster with the In-Context Slider. They found it easier to use and more natural for expressing interest. We then integrated the In-Context Slider in the agent-based system, combinFormation. We compared the In-Context Slider with combinFormation’s previous interest expression interface. Of the participants that effectively used both interfaces, most expressed more interest with the In-Context Slider. Participants’ experience reports described the In-Context Slider as easier to use while developing collections to answer open-ended information discovery questions. This research is relevant for many applications in which users provide ratings, such as recommender systems, as well as for others in which values need to be adjusted on many objects that are concurrently displayed.

In sheet metal forming (SMF), the major failure reason is galling. Galling is a process of different wear stages that leads to destruction of both the forming tool and the sheet metal working piece and is, because of that, of big economic importance for the SMF industries. Therefore, investigations and researches about how tool steels microstructure affect the tool steels galling resistance is of high priority. In the present work, different carbide properties were studied to find out how their properties affected the tool materials galling resistance. The investigated carbide properties were: Shape and size of the carbides   Carbide volume fraction Carbide distribution in the microstructure The investigation included three tools, all made of the PM tool steel S390, that were heattreated differently in order to achieve different carbide properties but still maintain the same hardness. The tools were galling tested in a slider-on-flat-surface (SOFS) tribometer to determine their galling resistances. In a scanning surface electron microscope (SEM) the tools galling marks were analyzed to find explanations for the SOFS tribometer results and the connection to the tools different carbide properties.  The investigations most galling resistant tool was the tool that had the microstructure with largest carbides which were distributed at grain boundaries and the second highest carbide volume fraction among the investigated tools.

Thesis (Ph. D.)--Carleton University, 1997. / Also available in electronic format on the Internet.