Enhancing Transparency and Control when Drawing Data-Driven Inferences about Individuals

Recent studies have shown that information disclosed on social network sites (such as Facebook) can be used to predict personal characteristics with surprisingly high accuracy. In this paper we examine a method to give online users transparency into why certain inferences are made about them by statistical models, and control to inhibit those inferences by hiding ("cloaking") certain personal information from inference. We use this method to examine whether such transparency and control would be a reasonable goal by assessing how difficult it would be for users to actually inhibit inferences. Applying the method to data from a large collection of real users on Facebook, we show that a user must cloak only a small portion of her Facebook Likes in order to inhibit inferences about their personal characteristics. However, we also show that in response a firm could change its modeling of users to make cloaking more difficult.Comment: presented at 2016 ICML Workshop on Human Interpretability in Machine Learning (WHI 2016), New York, N

Modeling travel time uncertainty in traffic networks

Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 147-154).Uncertainty in travel time is one of the key factors that could allow us to understand and manage congestion in transportation networks. Models that incorporate uncertainty in travel time need to specify two mechanisms: the mechanism through which travel time uncertainty is generated and the mechanism through which travel time uncertainty influences users' behavior. Existing traffic equilibrium models are not sufficient in capturing these two mechanisms in an integrated way. This thesis proposes a new stochastic traffic equilibrium model that incorporates travel time uncertainty in an integrated manner. We focus on how uncertainty in travel time induces uncertainty in the traffic flow and vice versa. Travelers independently make probabilistic path choice decisions, inducing stochastic traffic flows in the network, which in turn result in uncertain travel times. Our model, based on the distribution of the travel time, uses the mean-variance approach in order to evaluate travelers' travel times and subsequently induce a stochastic traffic equilibrium flow pattern. In this thesis, we also examine when the new model we present has a solution as well as when the solution is unique. We discuss algorithms for solving this new model, and compare the model with existing traffic equilibrium models in the literature. We find that existing models tend to overestimate traffic flows on links with high travel time variance-to-mean ratios. To benchmark the various traffic network equilibrium models in the literature relative to the model we introduce, we investigate the total system cost, namely the total travel time in the network, for all these models. We prove three bounds that allow us to compare the system cost for the new model relative to existing models. We discuss the tightness of these bounds but also test them through numerical experimentation on test networks.by Daizhuo Chen.S.M

Enhancing Transparency and Control when Drawing Data-Driven Inferences about Individuals

Recent studies show the remarkable power of information disclosed by users on social network sites to infer the users' personal characteristics via predictive modeling. In response, attention is turning increasingly to the transparency that sites provide to users as to what inferences are drawn and why, as well as to what sort of control users can be given over inferences that are drawn about them. We draw on the evidence counterfactual as a means for providing transparency into why particular inferences are drawn about them. We then introduce the idea of a \cloaking device" as a vehicle to provide (and to study) control. Specifically, the cloaking device provides a mechanism for users to inhibit the use of particular pieces of information in inference; combined with the transparency provided by the evidence counterfactual a user can control model-driven inferences, while minimizing the amount of disruption to her normal activity. Using these analytical tools we ask two main questions: (1) How much information must users cloak in order to significantly affect inferences about their personal traits? We find that usually a user must cloak only a small portion of her actions in order to inhibit inference. We also find that, encouragingly, false positive inferences are significantly easier to cloak than true positive inferences. (2) Can firms change their modeling behavior to make cloaking more difficult? The answer is a definitive yes. In our main results we replicate the methodology of Kosinski et al. (2013) for modeling personal traits; then we demonstrate a simple modeling change that still gives accurate inferences of personal traits, but requires users to cloak substantially more information to affect the inferences drawn. The upshot is that organizations can provide transparency and control even into complicated, predictive model-driven inferences, but they also can make modeling choices to make control easier or harder for their users.Columbia University, New York University, NYU Stern School of Business, NYU Center for Data Scienc

Enhancing Transparency and Control when Drawing Data-Driven Inferences about Individuals

Abstract Recent studies show the remarkable power of information disclosed by users on social network sites to infer the users' personal characteristics via predictive modeling. In response, attention is turning increasingly to the transparency that sites provide to users as to what inferences are drawn and why, as well as to what sort of control users can be given over inferences that are drawn about them. We draw on the evidence counterfactual as a means for providing transparency into why particular inferences are drawn about them. We then introduce the idea of a "cloaking device" as a vehicle to provide (and to study) control. Specifically, the cloaking device provides a mechanism for users to inhibit the use of particular pieces of information in inference; combined with the transparency provided by the evidence counterfactual a user can control model-driven inferences, while minimizing the amount of disruption to her normal activity. Using these analytical tools we ask two main questions: (1) How much information must users cloak in order to significantly affect inferences about their personal traits? We find that usually a user must cloak only a small portion of her actions in order to inhibit inference. We also find that, encouragingly, false positive inferences are significantly easier to cloak than true positive inferences. gives accurate inferences of personal traits, but requires users to cloak substantially more information to affect the inferences drawn. The upshot is that organizations can provide transparency and control even into complicated, predictive model-driven inferences, but they also can make modeling choices to make control easier or harder for their users

MODELING TRAVEL TIME UNCERTAINTYIN TRAFFIC NETWORK MODELS

Master'sMASTER OF SCIENCE IN COMPUTATIONAL ENGINEERIN

Synthesizing a novel genetic sequential logic circuit: a push‐on push‐off switch

Design and synthesis of basic functional circuits are the fundamental tasks of synthetic biologists. Before it is possible to engineer higher-order genetic networks that can perform complex functions, a toolkit of basic devices must be developed. Among those devices, sequential logic circuits are expected to be the foundation of the genetic information-processing systems. In this study, we report the design and construction of a genetic sequential logic circuit in Escherichia coli. It can generate different outputs in response to the same input signal on the basis of its internal state, and ‘memorize' the output. The circuit is composed of two parts: (1) a bistable switch memory module and (2) a double-repressed promoter NOR gate module. The two modules were individually rationally designed, and they were coupled together by fine-tuning the interconnecting parts through directed evolution. After fine-tuning, the circuit could be repeatedly, alternatively triggered by the same input signal; it functions as a push-on push-off switch