Community Detection in Multi-Layer Networks

In the scope of the current thesis we review and analyse networks that are formed by nodes with several attributes. We suppose that different layers of communities are embedded in such networks, besides each of the layers is connected with nodes' attributes. For example, examine one of a variety of online social networks: an user participates in a plurality of different groups/communities – schoolfellows, colleagues, clients, etc. We introduce a detection algorithm for the above-mentioned communities. Normally the result of the detection is the community supplemented just by the most dominant attribute, disregarding others. We propose an algorithm that bypasses dominant communities and detects communities which are formed by other nodes' attributes. We also review formation models of the attributed networks and present a Human Communication Network (HCN) model. We introduce a High School Texting Network (HSTN) and examine our methods for that network.

Six-month outcomes of a multi-campus smoking cessation contest

Background: Up to 40% of North American post-secondary students smoke at least occasionally, and most want to quit. Given students' preferences for free, easy-to-access, self-directed, convenient cessation methods, a motivational, incentive-based cessation contest may be an effective way to assist students to quit. The current study describes 3- and 6-month outcomes experienced by post-secondary student smokers who entered the 'Let's Make A Deal!' contest. Methodology: Contestants from five university campuses who chose to quit completely ('Quit For Good') or reduce their tobacco consumption by 50% ('Keep The Count') were invited to participate in a study of the contest. Three and six months after registration, participants were contacted by phone to assess their smoking and quitting behaviours. Qualitative and quantitative measures were collected, including weekly tobacco consumption, efficacy to resist temptations to smoke, use of quitting aids, and strategies to cope with withdrawal. Quitting was assessed using 7-day point prevalence and continuous abstinence. Results: Seventy-four (64.9%) of the 114 participants recruited for the study completed the follow-ups. Over 31 % of participants who entered Quit For Good and 23.5% of participants who entered Keep The Count were identified as quitters at the 6-month follow-up. Among the quitters, 45.5% experienced sustained abstinence from smoking for the 6-month duration of the study. Keep The Count contestants reduced their tobacco consumption by 57.2% at 3-month follow-up and sustained some of this reduction through to the 6-month follow-up. Qualitative data provides insights into how quitters coped with withdrawal and what hampered continuing smokers' efforts to quit. Significance: A motivational, incentive-based contest for post-secondary students can facilitate both smoking cessation and harm reduction. The contest environment, incentives, resources, and "buddies" provide positive structural and social supports to help smokers overcome potential barriers to quitting, successfully stop smoking, and manage potential triggers to relapse. The contest cessation rates are higher than the typical 5-7% associated with unassisted quitting.

On the anharmonic, multi-phonon, Debye-Waller contributions to the phonon-limited resistivity of metals : applications to Na and K

The anharmonic, multi-phonon (MP), and Oebye-Waller factor (OW) contributions to the phonon limited resistivity (;0) of metals derived by Shukla and Muller (1979) by the doubletime temperature dependent Green function method have been numerically evaluated for Na and K in the high temperature limit. The anharmonic contributions arise from the cubic and quartic shift of phonons (CS, QS), and phonon width (W) and the interference term (1). The QS, MP and OW contributions to I' are also derived by the matrix element method and the results are in agreement with those of Shukla and Muller (1979). In the high temperature limit, the contributions to;O from each of the above mentioned terms are of the type BT2 For numerical calculations suitable expressions are derived for the anharmonic contributions to ~ in terms of the third and fourth rank tensors obtained by the Ewald procedure. The numerical calculation of the contributions to;O from the OW, MP term and the QS have been done exactly and from the CS, Wand I terms only approximately in the partial and total Einstein approximations (PEA, TEA), using a first principle approach (Shukla and Taylor (1976)). The results obtained indicate that there is a strong pairwise cancellation between the: OW and MP terms, the QS and CS and the Wand I terms. The sum total of these contributions to;O for Na and K amounts to 4 to 11% and 2 to 7%, respectively, in the PEA while in the TEA they amount to 3 to 7% and 1 to 4%, respectively, in the temperature range.

What gets plans off the shelf? : a multi-site case study of the factors influencing municipal recreation plan implementation

Municipalities that engage in recreation planning have the potential to use their resources more effectively. However, successful planning means getting the plan off the shelf and implemented. This study investigated the factors that influenced municipal recreation plan implementation in three municipalities. Interviews were conducted with eleven key informants (recreation directors, planning consultants, a city councillor, and members of plan steering committees). The findings of this study suggested that because the implementation of recreation plans occurs in a highly political environment, recreation professionals will need effective strategies to get their plans implemented and that implementation can be facilitated by developing or expanding strategies that: (l) build the power of the recreation department within the municipal government structure; (2) build support for recreation within the local community; and (3) build the political and organizational capacity in the recreation department.

Search engine advertising in web retailing : an efficiency analysis

This study examines the efficiency of search engine advertising strategies employed by firms. The research setting is the online retailing industry, which is characterized by extensive use of Web technologies and high competition for market share and profitability. For Internet retailers, search engines are increasingly serving as an information gateway for many decision-making tasks. In particular, Search engine advertising (SEA) has opened a new marketing channel for retailers to attract new customers and improve their performance. In addition to natural (organic) search marketing strategies, search engine advertisers compete for top advertisement slots provided by search brokers such as Google and Yahoo! through keyword auctions. The rationale being that greater visibility on a search engine during a keyword search will capture customers' interest in a business and its product or service offerings. Search engines account for most online activities today. Compared with the slow growth of traditional marketing channels, online search volumes continue to grow at a steady rate. According to the Search Engine Marketing Professional Organization, spending on search engine marketing by North American firms in 2008 was estimated at $13.5 billion. Despite the significant role SEA plays in Web retailing, scholarly research on the topic is limited. Prior studies in SEA have focused on search engine auction mechanism design. In contrast, research on the business value of SEA has been limited by the lack of empirical data on search advertising practices. Recent advances in search and retail technologies have created datarich environments that enable new research opportunities at the interface of marketing and information technology. This research uses extensive data from Web retailing and Google-based search advertising and evaluates Web retailers' use of resources, search advertising techniques, and other relevant factors that contribute to business performance across different metrics. The methods used include Data Envelopment Analysis (DEA), data mining, and multivariate statistics. This research contributes to empirical research by analyzing several Web retail firms in different industry sectors and product categories. One of the key findings is that the dynamics of sponsored search advertising vary between multi-channel and Web-only retailers. While the key performance metrics for multi-channel retailers include measures such as online sales, conversion rate (CR), c1ick-through-rate (CTR), and impressions, the key performance metrics for Web-only retailers focus on organic and sponsored ad ranks. These results provide a useful contribution to our organizational level understanding of search engine advertising strategies, both for multi-channel and Web-only retailers. These results also contribute to current knowledge in technology-driven marketing strategies and provide managers with a better understanding of sponsored search advertising and its impact on various performance metrics in Web retailing.

The Albion, or British, Colonial and Foreign Weekly Gazette Vol. 5, No. 18- May 2, 1846. Article on Major General Isaac Brock and the 41st Regiment on the second (reverse) page.

A weekly paper published from 1822 to 1856.

The von Neumann Minimax Theorem and its relatives and a study of externality in on-line auctions

This work consists of a theoretical part and an experimental one. The first part provides a simple treatment of the celebrated von Neumann minimax theorem as formulated by Nikaid6 and Sion. It also discusses its relationships with fundamental theorems of convex analysis. The second part is about externality in sponsored search auctions. It shows that in these auctions, advertisers have externality effects on each other which influence their bidding behavior. It proposes Hal R.Varian model and shows how adding externality to this model will affect its properties. In order to have a better understanding of the interaction among advertisers in on-line auctions, it studies the structure of the Google advertisements networ.k and shows that it is a small-world scale-free network.

A Multi-Objective Genetic Algorithm with Side Effect Machines for Motif Discovery

Understanding the machinery of gene regulation to control gene expression has been one of the main focuses of bioinformaticians for years. We use a multi-objective genetic algorithm to evolve a specialized version of side effect machines for degenerate motif discovery. We compare some suggested objectives for the motifs they find, test different multi-objective scoring schemes and probabilistic models for the background sequence models and report our results on a synthetic dataset and some biological benchmarking suites. We conclude with a comparison of our algorithm with some widely used motif discovery algorithms in the literature and suggest future directions for research in this area.

DNA-Directed DNA Polymerases Evolve From Reverse Transcriptase

Scientists have been debating for decades the origin of life on earth. A number of hypotheses were proposed as to what emerged first RNA or DNA; with most scientists are in favour of the "RNA World" hypothesis. Assuming RNA emerged first, it fellow that the RNA polymerases would've appeared before DNA polymerases. Using recombinant DNA technology and bioinformatics we undertook this study to explore the relationship between RNA polymerases, reverse transcriptase and DNA polymerases. The working hypothesis is that DNA polymerases evolved from reverse transcriptase and the latter evolved from RNA polymerases. If this hypothesis is correct then one would expect to find various ancient DNA polymerases with varying level of reverse transcriptase activity. In the first phase of this research project multiple sequence alignments were made on the protein sequence of 32 prokaryotic DNA-directed DNA polymerases originating from 11 prokaryotic families against 3 viral reverse transcriptase. The data from such alignments was not very conclusive. DNA polymerases with higher level of reverse transcriptase activity were non-confined to ancient organisms, as one would've expected. The second phase of this project was focused on conditions that may alter the DNA polymerase activity. Various reaction conditions, such as temperature, using various ions (Ni2+, Mn2+, Mg2+) were tested. Interestingly, it was found that the DNA polymerase from the Thermos aquatics family can be made to copy RNA into DNA (i.e. reverse transcriptase activity). Thus it was shown that under appropriate conditions (ions and reactions temperatures) reverse transcriptase activity can be induced in DNA polymerase. In the third phase of this study recombinant DNA technology was used to generate a chimeric DNA polymerase; in attempts to identify the region(s) of the polymerase responsible for RNA-directed DNA polymerase activity. The two DNA polymerases employed were the Thermus aquatic us and Thermus thermophiles. As in the second phase various reaction conditions were investigated. Data indicated that the newly engineered chimeric DNA polymerase can be induced to copy RNA into DNA. Thus the intrinsic reverse transcriptase activity found in ancient DNA polymerases was localized into a domain and can be induced via appropriate reaction conditions.

Multi-Objective Genetic Algorithms for the Single Allocation Hub Location Problem

Hub Location Problems play vital economic roles in transportation and telecommunication networks where goods or people must be efficiently transferred from an origin to a destination point whilst direct origin-destination links are impractical. This work investigates the single allocation hub location problem, and proposes a genetic algorithm (GA) approach for it. The effectiveness of using a single-objective criterion measure for the problem is first explored. Next, a multi-objective GA employing various fitness evaluation strategies such as Pareto ranking, sum of ranks, and weighted sum strategies is presented. The effectiveness of the multi-objective GA is shown by comparison with an Integer Programming strategy, the only other multi-objective approach found in the literature for this problem. Lastly, two new crossover operators are proposed and an empirical study is done using small to large problem instances of the Civil Aeronautics Board (CAB) and Australian Post (AP) data sets.

Towards reverse engineering of Photosystem II: Synergistic Computational and Experimental Approaches

ABSTRACT Photosystem II (PSII) of oxygenic photosynthesis has the unique ability to photochemically oxidize water, extracting electrons from water to result in the evolution of oxygen gas while depositing these electrons to the rest of the photosynthetic machinery which in turn reduces CO2 to carbohydrate molecules acting as fuel for the cell. Unfortunately, native PSII is unstable and not suitable to be used in industrial applications. Consequently, there is a need to reverse-engineer the water oxidation photochemical reactions of PSII using solution-stable proteins. But what does it take to reverse-engineer PSII’s reactions? PSII has the pigment with the highest oxidation potential in nature known as P680. The high oxidation of P680 is in fact the driving force for water oxidation. P680 is made up of a chlorophyll a dimer embedded inside the relatively hydrophobic transmembrane environment of PSII. In this thesis, the electrostatic factors contributing to the high oxidation potential of P680 are described. PSII oxidizes water in a specialized metal cluster known as the Oxygen Evolving Complex (OEC). The pathways that water can take to enter the relatively hydrophobic region of PSII are described as well. A previous attempt to reverse engineer PSII’s reactions using the protein scaffold of E. coli’s Bacterioferritin (BFR) existed. The oxidation potential of the pigment used for the BFR ‘reaction centre’ was measured and the protein effects calculated in a similar fashion to how P680 potentials were calculated in PSII. The BFR-RC’s pigment oxidation potential was found to be 0.57 V, too low to oxidize water or tyrosine like PSII. We suggest that the observed tyrosine oxidation in BRF-RC could be driven by the ZnCe6 di-cation. In order to increase the efficiency of iii tyrosine oxidation, and ultimately oxidize water, the first potential of ZnCe6 would have to attain a value in excess of 0.8 V. The results were used to develop a second generation of BFR-RC using a high oxidation pigment. The hypervalent phosphorous porphyrin forms a radical pair that can be observed using Transient Electron Paramagnetic Resonance (TR-EPR). Finally, the results from this thesis are discussed in light of the development of solar fuel producing systems.

Group-invariant solutions of semilinear Schrodinger equations in multi-dimensions

Symmetry group methods are applied to obtain all explicit group-invariant radial solutions to a class of semilinear Schr¨odinger equations in dimensions n = 1. Both focusing and defocusing cases of a power nonlinearity are considered, including the special case of the pseudo-conformal power p = 4/n relevant for critical dynamics. The methods involve, first, reduction of the Schr¨odinger equations to group-invariant semilinear complex 2nd order ordinary differential equations (ODEs) with respect to an optimal set of one-dimensional point symmetry groups, and second, use of inherited symmetries, hidden symmetries, and conditional symmetries to solve each ODE by quadratures. Through Noether’s theorem, all conservation laws arising from these point symmetry groups are listed. Some group-invariant solutions are found to exist for values of n other than just positive integers, and in such cases an alternative two-dimensional form of the Schr¨odinger equations involving an extra modulation term with a parameter m = 2−n = 0 is discussed.

New conserved vorticity integrals for moving surfaces in multi-dimensional fluid flow

For inviscid fluid flow in any n-dimensional Riemannian manifold, new conserved vorticity integrals generalizing helicity, enstrophy, and entropy circulation are derived for lower-dimensional surfaces that move along fluid streamlines. Conditions are determined for which the integrals yield constants of motion for the fluid. In the case when an inviscid fluid is isentropic, these new constants of motion generalize Kelvin’s circulation theorem from closed loops to closed surfaces of any dimension.

Characterizing Dynamic Optimization Benchmarks for the Comparison of Multi-Modal Tracking Algorithms

Population-based metaheuristics, such as particle swarm optimization (PSO), have been employed to solve many real-world optimization problems. Although it is of- ten sufficient to find a single solution to these problems, there does exist those cases where identifying multiple, diverse solutions can be beneficial or even required. Some of these problems are further complicated by a change in their objective function over time. This type of optimization is referred to as dynamic, multi-modal optimization. Algorithms which exploit multiple optima in a search space are identified as niching algorithms. Although numerous dynamic, niching algorithms have been developed, their performance is often measured solely on their ability to find a single, global optimum. Furthermore, the comparisons often use synthetic benchmarks whose landscape characteristics are generally limited and unknown. This thesis provides a landscape analysis of the dynamic benchmark functions commonly developed for multi-modal optimization. The benchmark analysis results reveal that the mechanisms responsible for dynamism in the current dynamic bench- marks do not significantly affect landscape features, thus suggesting a lack of representation for problems whose landscape features vary over time. This analysis is used in a comparison of current niching algorithms to identify the effects that specific landscape features have on niching performance. Two performance metrics are proposed to measure both the scalability and accuracy of the niching algorithms. The algorithm comparison results demonstrate the algorithms best suited for a variety of dynamic environments. This comparison also examines each of the algorithms in terms of their niching behaviours and analyzing the range and trade-off between scalability and accuracy when tuning the algorithms respective parameters. These results contribute to the understanding of current niching techniques as well as the problem features that ultimately dictate their success.