Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 121-129).

Thesis (M.S.)--Middle East Technical University, 2003. / Keywords: GIS, geophysics, geology, galatean volcanic province.

Thesis (M.U.D.)--University of Hong Kong, 2000. / Includes bibliographical references.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Artificial Intelligence Lab, Department of MIS, University of Arizona / This research examined the applicability of using a neural network approach to the estimation of aqueous activity coefficients of aromatic organic compounds from fragmented structural information. A set of 95 compounds was used to train the neural network, and the trained network was tested on a set of 31 compounds. A comparison was made between the results and those obtained using multiple linear regression analysis. With the proper selection of neural network parameters, the backpropagation network provided a more accurate prediction of the aqueous activity coefficients for testing data than did regression analysis. This research indicates that neural networks have the potential to become a useful analytical technique for quantitative prediction of structure-activity relationships.

Artificial Intelligence Lab, Department of MIS, University of Arizona / This research presents an algorithmic approach to addressing the vocabulary problem in scientific information retrieval and information sharing, using the molecular biology domain as an example. We first present a literature review of cognitive studies related to the vocabulary problem and vocabuiary-based search aids (thesauri) and then discuss techniques for building robust and domain-specific thesauri to assist in cross-domain scientific information retrieval. Using a variation of the automatic thesaurus generation techniques, which we refer to as the concept space approach, we recently conducted an experiment in the molecular biology domain in which we created a C. elegans worm thesaurus of 7,657 worm-specific terms and a Drosofila fly thesaurus of 15,626 terms. About 30% of these terms overlapped, which created vocabulary paths from one subject domain to the other. Based on a cognitive study of term association involving four biologists, we found that a large percentage (59.6-85.6%) of the terms suggested by the subjects were identified in the conjoined fly-worm thesaurus. However, we found only a small percentage (8.4-18.1%) of the associations suggested by the subjects in the thesaurus. In a follow-up document retrieval study involving eight fly biologists, an actual worm database (Worm Community System), and the conjoined flyworm thesaurus, subjects were able to find more relevant documents (an increase from about 9 documents to 20) and to improve the document recall level (from 32.41 to 65.28%) when using the thesaurus, although the precision level did not improve significantly. Implications of adopting the concept space approach for addressing the vocabulary problem in Internet and digital libraries applications are also discussed.

No description available.

It is believed that the next few decades will witness the booming development of the Internet of Things (IoT). Vehicular network, as a significant component of IoT, has attracted lots of attention from both academia and industry in recent years. In the field of vehicular networks, Vehicular Ad hoc NETwork (VANET) is one of the hottest topics investigated. This dissertation focuses on VANET geocast, which is a special form of multicast in VANET. In geocast, messages are delivered to a group of destinations in the network identified by their geographic locations. Geocast has many promising applications, i.e., geographic messaging, geographic advertising and other location-based services. Two phases are usually considered in the geocast process: phase one, message delivery from the message source to the destination area by geographic routing; phase two, message broadcast within the destination area. This dissertation covers topics in the two phases of geocast in urban VANETs, where for phase one, a data-driven geographic routing scheme and a security and privacy preserving framework are presented; and for phase two, the networking connectivity is analyzed and studied. The contributions of this dissertation are three-fold. First, from a real-world data trace study, this dissertation studies the city taxi- cab mobility. It proposes a mobility-contact-aware geocast scheme (GeoMobCon)for metropolitan-scale urban VANETs. The proposed scheme employs the node mobility (two levels, i.e., macroscopic and microscopic mobilities) and contact history information. A buffer management scheme is also introduced to further improve the performance. Second, this dissertation investigates the connectivity of the message broadcast in urban scenarios. It models the message broadcast in urban VANETs as the directed connectivity problem on 2D square lattices and proposes an algorithm to derive the exact analytical solution. The approach is also applied to urban VANET scenarios, where both homogeneous and heterogeneous vehicle density cases are considered. Third, this work focuses on the security and privacy perspectives of the opportunistic routing, which is the main technique utilized by the proposed geographic routing scheme. It proposes a secure and privacy preserving framework for the general opportunistic-based routing. A comprehensive evaluation of the framework is also provided. In summary, this dissertation focuses on a few important aspects of the two phases of VANET geocast in urban scenarios. It shows that the vehicle mobility and contact information can be utilized to improve the geographic routing performance for large- scale VANET systems. Targeting at the opportunistic routing, a security and privacy preserving framework is proposed to preserve the confidentiality of the routing metric information for the privacy purpose, and it also helps to achieve the anonymous authentication and efficient key agreement for security purposes. On the other hand, the network connectivity for the message broadcast in urban scenarios is studied quantitatively with the proposed solution, which enables us to have a better understanding of the connectivity itself and its impact factors (e.g., bond probability and network scale). / Graduate

Thesis (PhD)--University of South Australia, 1999

Thesis (PhDTransportSystemsEng)--University of South Australia, 2002.