Off-Policy Evaluation of Probabilistic Identity Data in Lookalike Modeling

We evaluate the impact of probabilistically-constructed digital identity data collected from Sep. to Dec. 2017 (approx.), in the context of Lookalike-targeted campaigns. The backbone of this study is a large set of probabilistically-constructed "identities", represented as small bags of cookies and mobile ad identifiers with associated metadata, that are likely all owned by the same underlying user. The identity data allows to generate "identity-based", rather than "identifier-based", user models, giving a fuller picture of the interests of the users underlying the identifiers. We employ off-policy techniques to evaluate the potential of identity-powered lookalike models without incurring the risk of allowing untested models to direct large amounts of ad spend or the large cost of performing A/B tests. We add to historical work on off-policy evaluation by noting a significant type of "finite-sample bias" that occurs for studies combining modestly-sized datasets and evaluation metrics involving rare events (e.g., conversions). We illustrate this bias using a simulation study that later informs the handling of inverse propensity weights in our analyses on real data. We demonstrate significant lift in identity-powered lookalikes versus an identity-ignorant baseline: on average ~70% lift in conversion rate. This rises to factors of ~(4-32)x for identifiers having little data themselves, but that can be inferred to belong to users with substantial data to aggregate across identifiers. This implies that identity-powered user modeling is especially important in the context of identifiers having very short lifespans (i.e., frequently churned cookies). Our work motivates and informs the use of probabilistically-constructed identities in marketing. It also deepens the canon of examples in which off-policy learning has been employed to evaluate the complex systems of the internet economy.Comment: Accepted by WSDM 201

Tensor Network States: Optimizations and Applications in Quantum Many-Body Physics and Machine Learning

Tensor network states are ubiquitous in the investigation of quantum many-body (QMB) physics. Their advantage over other state representations is evident from their reduction in the computational complexity required to obtain various quantities of interest, namely observables. Additionally, they provide a natural platform for investigating entanglement properties within a system. In this dissertation, we develop various novel algorithms and optimizations to tensor networks for the investigation of QMB systems, including classical and quantum circuits. Specifically, we study optimizations for the two-dimensional Ising model in a transverse field, we create an algorithm for the $k$-SAT problem, and we study the entanglement properties of random unitary circuits. In addition to these applications, we reinterpret renormalization group principles from QMB physics in the context of machine learning to develop a novel algorithm for the tasks of classification and regression, and then utilize machine learning architectures for the time evolution of operators in QMB systems

Filter mediated design : generating coherence in (collaborative) design

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 1999.Includes bibliographical references (leaves 67-69).Architectural design involves the integration of diverse, sometimes conflicting, concepts and requirements into a coherent single composition. This paper proposes a method for negotiating architectural design across domains, by examining issues of ontology, perception, generation and evaluation, and detailing a prototype in which these mechanisms are augmented using computational agents for achieving coherence and innovation in remote collaborative design. The paper proposes a common geometric and topological database, from which multiple semantic models are constructed. Filter Mediated Design is intended to explore the processes and strategies of constructing intelligent designs and design intelligence.by John R. Haymaker.S.M

Visualization for Biological Models, Simulation, and Ontologies

In this dissertation, I present three browsers that I have developed for the purpose of exploring, understanding, and analyzing models, simulations, and ontologies in biology and medicine. The first browser visualizes multidimensional simulation data as an animation. The second browser visualizes the equations of a complex model as a network and puts structure and organization on top of equations and variables. The third browser is an ontology viewer and editor, directly intended for the Foundational Model of Anatomy (FMA), but applicable to other ontologies as well. This browser has two contributions. First, it is a lightweight deliverable that lets someone easily dabble with the FMA. Second, it lets the user edit an ontology to create a view of it. For the ontology browser, I also conduct user studies to refine and evaluate the software

Entrepreneurship in rural areas: Examining the influence of postsecondary education

Almost nineteen (19) percent of the United States population lives in rural areas according to the 2010 Census. Deficiencies in diversity of skilled labor, business support networks, and consumer demand have resulted in major barriers to economic prosperity in many of these areas. State and local governments commit valuable time and resources to economic development programs to revitalize rural communities. While post-secondary education institutions significantly augment the ecosystem, research has shown that the framework of the institution will determine the extent of the institution’s impact on entrepreneurship and economic growth. This study undertakes the research questions “Does post-secondary education influence economic performance through entrepreneurship in rural areas? What contributes to post-secondary education’s influence on entrepreneurship in rural areas?” This research used a mixed method, empirical study. Quantitative analysis is used to examine the degree that postsecondary education, entrepreneurial activity and economic performance are related to each other and to measure the strength of the association between variables. Descriptive statistics provide a summary of the variables under review. Secondarily, a qualitative study provides deeper insight for understanding quantitative findings. Data from 85 rural Georgia counties provide an opportunity sample used for this research. This study reveals that institutions are performing in four principal roles: organizational, intermediary, knowledge and policy that produce resources influencing entrepreneurship and economic performance in rural areas. Findings from this study may lead to better decision making about strategic use of postsecondary education resources for economic development in rural areas

Patterns and Interactions in Network Security

Networks play a central role in cyber-security: networks deliver security attacks, suffer from them, defend against them, and sometimes even cause them. This article is a concise tutorial on the large subject of networks and security, written for all those interested in networking, whether their specialty is security or not. To achieve this goal, we derive our focus and organization from two perspectives. The first perspective is that, although mechanisms for network security are extremely diverse, they are all instances of a few patterns. Consequently, after a pragmatic classification of security attacks, the main sections of the tutorial cover the four patterns for providing network security, of which the familiar three are cryptographic protocols, packet filtering, and dynamic resource allocation. Although cryptographic protocols hide the data contents of packets, they cannot hide packet headers. When users need to hide packet headers from adversaries, which may include the network from which they are receiving service, they must resort to the pattern of compound sessions and overlays. The second perspective comes from the observation that security mechanisms interact in important ways, with each other and with other aspects of networking, so each pattern includes a discussion of its interactions.Comment: 63 pages, 28 figures, 56 reference

Contributions to adaptive equalization and timing recovery for optical storage systems

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