The problem of influence maximization has been studied extensively with applications that include viral marketing, recommendations, and feed ranking. The optimization problem, first formulated by Kempe, Kleinberg and Tardos, is known to be NP-hard. Thus, several heuristics have been proposed to solve this problem. This thesis studies the problem of influence maximization under the deterministic linear threshold model and presents a novel heuristic for finding influential nodes in a graph with the goal of maximizing contagion spread that emanates from these influential nodes. Inputs to our algorithm include edge weights and vertex thresholds. The threshold difference greedy algorithm presented in this thesis takes into account both the edge weights as well as vertex thresholds in computing influence of a node. The threshold difference greedy algorithm is evaluated on 14 real-world networks. Results demonstrate that the new algorithm performs consistently better than the seven other heuristics that we evaluated in terms of final spread size. The threshold difference greedy algorithm has tuneable parameters which can make the algorithm run faster. As a part of the approach, the algorithm also computes the infected nodes in the graph. This eliminates the need for running simulations to determine the spread size from the influential nodes. We also study the target set selection problem with our algorithm. In this problem, the final spread size is specified and a seed (or influential) set is computed that will generate the required spread size. / Master of Science

Making the decision to live abroad means departing from a known culture and language. I know the culture and language of my home country Germany, and living here makes it easy to learn the culture and language of the United States. But for one who does not have the opportunity to live abroad learning the culture and language of a foreign country is a challenge. Germany is relatively well represented in Washington D.C.: the German embassy and its information center on Foxhall Road, the Goethe-Institut on 7th Street NW, the American Institute for Contemporary German Studies on Massachusetts Avenue, and the German Historical Society on New Hampshire Avenue. But as one can see from the list the institutes are spread throughout the city. The Goethe-Institut is the most public institution, and I therefore chose it to be the main user of the planned German Cultural Center. I am seeking to bring all of the named institutions together into one building, with the exception of the embassy itself. Through this effort a center of language and culture will be made, where one can go to learn and experience a foreign country within another country. The institutions themselves will profit from the collaboration with each other, minimizing their financial obligations and at the same time profiting from the collaboration with the other institutes. This thesis project seeks to prove that it is possible to represent a country with its language and culture through a good building. Germany has much more to offer than the typical cliches and the New German Cultural Institute will be the place to experience this other side of the country. / Master of Architecture

A cluster of buildings does not a campus make. Places of learning have long sought-out cohesive spaces that foster a sense of community and encourage an immersive life of academia. The suburban campus model, with a centric configuration, has been a successful model that has withstood the test of time. Urban campuses knitted into the urban fabric have also had success in fostering the same sense of community, but more so as part of the larger city, and using the urban context as a lab for teaching. But what makes the campuses we love successful? And how can we apply those principles to set up younger campuses for future success? This thesis tackles these questions, and attempts to understand what differentiates a mere collection of buildings from a true campus. Applied to the Washington Alexandria Architecture Center, these borrowed ideas can start to inform the design of a new campus that bridges the gap between traditional suburban campuses and organic urban campuses. Rather than providing a series of definitive answers, the thesis establishes a series of principles on how to create a cohesive design that doesn't compromise the true nature of an urban campus. The proposed design is but one of many possible solutions. As humans, we seem to have a desire to classify the world into categories. Oftentimes, however, the most beautiful things come from the tension of the unclassified. They come from the gray areas between typologies. The process of this thesis became inherently contradictory at times. It was developed in a way in which the particular conditions of the existing buildings on the site, and their character in the urban setting, were allowed to contaminate the clarity of the suburban campus typology, and as such, become in many ways an oxymoron. / Master of Architecture

Architecture that embodies contradiction has the opportunity to be a separation while creating new avenues. Separations help by distinguishing the two dualities. This thesis is an exploration on Architecture's response within complexity and contradiction. Within my project, the driving parameter is the program: A monastery for the Dominican order within an urban context of Washington DC. The architecture has two primary responsibilities, one is to preserve the sanctity of a restricted way of living and the other to engage with its profane surrounding. The two most important questions are: how does a monastery represent itself to a city; and how does a city represent itself from within a monastery. / Master of Architecture / Architecture that embodies contradiction has the opportunity to be a separation while creating new avenues. Separations help by distinguishing the two dualities. This thesis is an exploration on Architecture's response within complexity and contradiction. Within my project, the driving parameter is the program: A monastery for the Dominican order within an urban context of Washington DC. The architecture has two primary responsibilities, one is to preserve the sanctity of a restricted way of living and the other to engage with its profane surrounding. The two most important questions are: how does a monastery represent itself to a city; and how does a city represent itself from within a monastery.

When thinking about architecture, I cannot help but think about my life and the things that have affected my life. How does the environment around us effect the daily decisions we make? How do the experiences throughout our life impact who we are and who we become? The people and surroundings we choose will ultimately decide the type of people we become. When we select our surroundings we are in turn selecting our ideal community. Everyone is trying to achieve community in some sense, from individuals to city planners. Council members, politicians, city officials... make decisions everyday based on their idea of what community is to them and their citizens. In the following pages I will design a community and put in place the elements for it to prosper and grow... / Master of Architecture

A numerical model which determines the geometry of a threshold channel was recently developed. Such a model is an important tool for designing unlined irrigation canals and channelization schemes, and is useful when considering flow regulation. However, its applicability is limited in that its continuously curving boundary does not allow for sediment transport, which is an essential feature of natural rivers and streams. That model has thus been modified to predict the shape and stress distribution of an optimal stable channel; a channel with a flat-bed region over which bedload transport occurs, and curving bank regions composed of particles that are all in a state of incipient motion. It is the combination of this channel geometry and the phenomenon of momentum-diffusion, that allows the present model to simulate the "stable bank, mobile bed" condition observed in rivers. The coupled equations of momentum-diffusion and force-balance are solved over the bank region to determine the shape of the channel banks (the bank solution). The width of the channel1s flat-bed region is determined by solving the momentum-diffusion equation over the flat-bed region (the bed solution), using conditions at the junction of the flat-bed and bank regions that ensure matching of the bed and bank solutions. The model was tested against available experimental and field data, and was found to adequately predict the bank shape and significant dimensions of stable channels. To make the model results more amenable to the practic ing engineer, design equations and plots were developed. These can be used as an alternative solution for stable channel design; relieving the practitioner of the need to run the numerical program. The case of a stable channel that transports both bedload and suspended sediment is briefly discussed. Governing equations and a possible solution scheme for this type of channel are suggested; laying the groundwork for the development of an appropriate numerical model. / Ph. D.

Poly(ethylene terephthalate) (PETE) packaging is becoming an increasingly popular choice of packaging material for milk, but has the disadvantage of releasing odorous acetaldehyde into food matrices. Sensory detection group thresholds for acetaldehyde in whole, low fat and nonfat unflavored milks were 3939, 4020, and 4040 ppb respectively with no significant difference due to fat level. Chocolate flavored milk and spring water showed detection thresholds levels for acetaldehyde of 10048 and 167 ppb respectively. This information assisted in determining if acetaldehyde migration from the package to the product would influence the flavor of the product. Whole milk was packaged in glass, high density polyethylene (HDPE), amber PETE, clear PETE, and clear PETE with UV light block and was exposed to fluorescent light of 1100-1300 lux (100-120 FC) at 4oC for 18 days. Sensory and chemical analysis and was done on milk from all containers over a period of 18 days. Emphasis was on oxidation, acetaldehyde and lacks freshness off-flavors and byproducts. All volatile flavor compounds studied (acetaldehyde, pentanal, dimethyl disulfide, and hexanal) were increased in light-exposed milk samples. Amber PETE showed the least amount of oxidation off-flavor, while clear PETE with UV block showed significantly less oxidation off-flavor than glass, clear PETE or HDPE on day 7 and 18. Acetaldehyde was not detected by sensory analysis in either light-exposed or light-protected samples. Chemical analysis showed relative acetaldehyde levels in glass (2220 ppb), HDPE (1265 ppb), amber PETE (3397 ppb), clear PETE (2930 ppb), and clear PETE with UV light block (1754 ppb) were all below concentrations found for human flavor threshold. / Master of Science

This thesis is a study of the threshold as a materialization of spatial limit; individually absolute in definition, but often part of a transition of greater scale. With the program of a public library serving as a vehicle for study, the project seeks to explore the role threshold has with the procession in architecture. This concept of spatial limit serves many roles, be it a marker of progress along the procession, a connector and separator between conflicting spatial conditions, or a manifestation of hierarchy within the building. / Master of Architecture

An architect draws from a deep repository of past memories made durable in the act of architecture. This thesis is a study of the analogous relationship between a childhood memory of a garden and a set of architectural acts giving form to this memory. The ideas of threshold, meander, focus, and framing are the basic conditions of the project. Perspectives and montages are the primary methods of study. The project is a garden placed within the context of an imagined city setting up the interplay of silence amidst the cacophony of the city. It centers around a singular tree, informed by a specific childhood memory. The single tree in concert with the architectural conditions allows one to resist the inexorable rush of urban time. / Master of Architecture / An architect draws from memories of the past to inform the future. This thesis is a study that pulls from memories of a childhood garden and compares them to a set of basic architectural elements. The ideas of threshold, meander, focus, and framing are explored.

This thesis investigates how architecture engages with the natural landscape through iterative designs of exhibition space. Proposals of architecture adjacent to Smith Mountain Lake as well as along the Cascade Falls Trail in Virginia were considered. The design proposals led to a resolution that particular considerations are critical in relating architecture and nature, specifically a building's spatial organization and orientation, its materiality and tectonic assembly, and the bounding thresholds differentiating between inside and outside. / Master of Architecture / The central idea of my exploration is to engage with nature and create a building that relates to the Virginian landscape consisting of mountain, forest and water. The design exploration began with a site at Smith Mountain Lake and then a site at Cascade Falls Trail. To make the architecture, many aspects were considered - how to place the architecture in the landscape, the choice of the building's materials, how the building is constructed, the use of walls versus windows, and finally, not only creating a relationship between architecture and landscape, but also determining nuanced ways to connect the two.