<div>This study introduced a design-inspired approach to unpack problems of professional formation</div><div>of engineers: 1) the gap between what students learn in universities and what they practice upon</div><div>graduation; 2) the perception that engineering is solely technical, math, and theory oriented; and</div><div>3) the lack of diversity and inclusion (incorporation of difference in perspectives, values, and</div><div>ways of thinking and being engineers) in many engineering programs. The current project</div><div>investigated the discursive practices and institutional processes that contributed to or inhibited</div><div>innovative and inclusive professional formation within an undergraduate engineering setting.</div><div>Specifically, this project showed how Grounded Practical Theory (GPT), Communication as</div><div>Design (CaD), and Human-Centered Design (HCD) offer alternative pathways to conceptualize</div><div>the processes of professional formation.</div><div><br></div><div><div>The context for this study involved the professional formation of engineers at a School of</div><div>Biomedical Engineering (BME) at a large, Midwestern university. Participants for this study</div><div>included undergraduate students and faculty, staff, and administration (FSA). Semi-structured</div><div>interview data was collected and explored participants’ descriptions, accounts, and experiences</div><div>related to professional engineering formation in BME. Data collection included 33 total</div><div>interviews including 15 FSA and 18 student interviews. The study involved an empirical</div><div>examination of discursive practices that invoked, reproduced, and maintained discourses of</div><div>professional engineering at the BME school.</div></div><div><br></div><div><div>Based on insights gained from the empirical examination of discursive practices, a GPT</div><div>framework was applied to examine conflicts in professional formation, strategies participants</div><div>used to overcome these challenges, and the underlying rationale for these strategies. Specifically, the goal of gaining a broad knowledge base—incorporating expertise across various engineering</div><div>and science disciplines—often can come at the expense of realizing specific application and</div><div>technical know-how. For many participants, both goals were critical for becoming a professional</div><div>biomedical engineer but often times blocked a discourse of professional formation that was</div><div>innovative and inclusive. Participants revealed that a standard lecture curriculum influenced this</div><div>tension, in many cases for the worse. However, findings suggested that strategies for overcoming</div><div>these conflicts were by integrating lecture curricula with more active learning formats (e.g.,</div><div>undergraduate research, lab participation). Moreover, findings showed how standard lecture</div><div>communication designs shaped and maintained a discourse community more likely to emphasize</div><div>understanding engineering as a science and also gaining a broad knowledge base often times at</div><div>the expense of realizing specific application and technical know-how.</div></div><div><br></div><div><div>This study’s analysis offers several theoretical contributions. First, GPT pointed to the deeply</div><div>integrated relationship between the ontological and epistemological foundations of biomedical</div><div>engineering professional formation. That is, becoming a biomedical engineer meant having</div><div>knowledge of several sets of disciplinary expertise while also understanding when and how to</div><div>enact this knowledge in practice. Second, professional formation designs for communication</div><div>(e.g., lecture designs, active learning designs) presupposed something about the recurrent</div><div>practices held within the school and how these recurrent practices constituted professional</div><div>ontology and epistemology in ways that were both enabling and problematic, Third, and from a</div><div>HCD perspective, exploring designs for communication brought to life the ways participants,</div><div>through interactivity, actively designed discourses of professional formation in an attempt to</div><div>achieve and meet their epistemological and ontological goals.</div></div>

The ever-growing demand for higher bandwidth broadband communication has driven transistor operation to higher and higher frequencies. However, achieving cut-o frequencies in the terahertz regime have been unsuccessful with the current state-of-the-art transistors exhibiting no better than 800 GHz. While the high-frequency transistor eld is dominated by III-V semiconductors, it has been proposed that graphene may be a competitive material. Graphene exhibits electron and hole mobilities orders of magnitude larger than conventional semiconductors and has an atomically thin form factor. Despite these benets, high-frequency graphene transis tors have yet to realize high-frequency characteristics better than III-V's. This thesis expands on the current limitations of graphene transistors in terms of improved fabrication techniques (to achieve higher carrier mobilities and lower contact resistances) and fundamental, band structure limitations (like quantum capacitance and the zero energy band gap). First, graphene, fully encapsulated in hexagonal boron-nitride crystals, transistors are fabricated with self-aligned source and drain contacts with sub-100 nm gate lengths. The encapsulation technique shields the graphene from the external environment so that graphene retains its intrinsic high mobility characteristic. In this short-channel regime, transport is determined to be ballistic with an injection velocity close to the Fermi velocity of graphene. However, the transconductance and output conductance are only 0.6 mS/mm and 0.3 mS/mm, respectively. This lack-luster performance is due to a relatively thick (3.5 nm) eective oxide thickness but also due to the eects of quantum capacitance which diminishes the total gate capacitance by up to 60%. Furthermore, the output conductance is increased due to the onset of hole conduction which leads to a second linear regime in the I-V characteristic. This is a direct consequence of graphene's zero energy band gap electronic structure. Finally, the source and drain contact resistances are large, which leads to poorer output current, transconductance and output conductance. Second, improvement to the contact resistance is explored by means of using graphite as the contact metal to graphene. Since graphite is atomically smooth, a pristine graphite-graphene interface can be formed without grain asperities found in conventional metals. Graphite is also lattice matched to graphene and exhibits the same 60 symmetry. Consequently, it is discovered that the graphite-graphene contact resistance exhibits a 60 periodicity, with respect to crystal orientation. When the two lattices align, a contact resistivity under 10 Wmm² is observed. Furthermore, contact resistivity minima are observed at two of the commensurate angles of twisted bilayer graphene. Though graphene transistor performance is band structure limited, it may still be possible to achieve competitive high-frequency operation by use of h-BN encapsulation and graphite contacts.

M. Tech. Electrical Engineering.. / Wireless mesh networks (WMNs) have become a better alternative for extending wireless Local Area Networks (WLANs) to provide network coverage up to the furthest of far flung rural areas. This has been implemented by using a meshed backbone network interconnecting the mesh access points (MAPs) that manage each of the WLANs, thus providing a vital mode complimentary to the wireless infrastructure-based networks. The benefits of WMN deployments, however, come with certain challenges e.g., power management. Due to the limited availability of power in typical rural areas in Africa, this dissertation presents an energy efficient localized distributed topology control algorithm to efficiently manage power consumption at the backbone of the wireless mesh networks. The goal is to extend these networks’ lifetimes, as well as improve on throughput. The focus of the project is on the application of the WMNs in rural areas in Africa and in remote urban areas where the mesh nodes are mostly powered by exhaustible power sources like wet-cells or diesel controlled power generators and hence, are considered power constrained. The proposed algorithm uses the propagation models and the concept of relay region to obtain an optimal transmission power per node. It further applies a topology management protocol framework to limit the average number of neighbours per node, which helps to reduce internodes interferences during communication. The performance of the algorithm is validated through extensive simulations in the Network Simulator (NS-2) environment. The results are further compared to those of the conventional IEEE 802.11b mesh network, without transmission power control. It is shown that with a reduction in per node transmission power via topology control it is possible to reduce the total energy consumption in the overall network. It is further shown that this reduction may lead to poor performance in capacity. Hence, it is important to ensure a proper balance in the transmit power to obtain a balance in energy efficiency as well as in throughput.

M. Tech. Electrical Engineering. / Discusses the transport of real time data in WMNs as a challenging problem. The main cause of this problem is transport layer protocols. These protocols have traditionally been used successfully for wired networks. However, their raw implementation in wireless networks has proven to be inefficient, since wireless channels are characterized by a higher Bit Error Rate (BER), Packet Loss Rate (PLR), interference, bandwidth limitations and mobility when compared to wired network channels. Thus, for the efficient transport of real time video in WMNs, transport protocols need to be adapted to be adapted to wireless networks since they were not originally developed for this application.

Interaction with mobile devices suffers from a number of shortcomings, most of which are linked to the small size of screens. Artificial tactile feedback promises to be particularly well suited to the mobile interaction context. To be practical, tactile transducers for mobile devices must be small and light, and yet be capable of displaying a rich set of expressive stimuli. This thesis introduces a tactile transducer for mobile interaction that is capable of distributed skin stimulation on the fingertip. The transducer works on a principle that was first investigated because of its potential application to the display of Braille. A preliminary study was conducted on an earlier version of the transducer. It concluded that subjects were able to identify simple Braille characters with a high rate of success. Then, a complete re-design of the transducer addressed the goal of integration in a handheld prototype for mobile interaction. The resulting device comprises a liquid crystal graphic display co-located with the miniature, low-power, distributed tactile transducer. Next, it was needed to measure the perceptual differences between the stimuli that the device could display. Our experiences with one evaluation approach raised questions relating to the methodology for data collection. Therefore, an analysis of the process was carried out using a stimulus set obtained with the device. By means of multidimensional scaling analysis, both the perceptual parameters forming the stimuli space and the evaluation technique were validated. Finally, two experiments were carried out with the objective to develop new mobile interactions paradigms that combined visual and tactile feedback. Both experiments modeled a list scrolling task on the device. The first experiment found a marginal improvement in performance when tactile feedback was employed. It also came at a higher attentional cost dedicated to operating the device. For the second experiment, the scrolling paradigm and the tactile feedback were improved. This lead to a decrease in the reliance on vision when tactile feedback was enabled. Results showed a 28% decrease in the number of key presses that controlled the visibility state of the scroll list.

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Thesis (Ph.D.) -- University of Western Sydney, 2003. / Thesis submitted for the Degree of Doctor of Philosophy (Design), University of Western Sydney, 2003". Includes bibliography : leaves 263 - 270.

Thesis (M.F.A.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (leaves [122]-124).

Thesis (M.S.)--West Virginia University, 1995.

Proefschrift--Technische Universiteit Delft, 1996. / Includes bibliographical references (p. 149-159) and indexes.