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Creators/Authors contains: "Landau, Susan"

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  1. In this paper, we examine private-sector collection and use of metadata and telemetry information and provide three main contributions: First, we lay out the extent to which “non-content”—the hidden parts of Internet communications (aspects the user does not explicitly enter) and telemetry—are highly revelatory of personal behavior. We show that, privacy policies notwithstanding, users rarely know that the metadata and telemetry information is being collected and almost never know the uses to which it is being put. Second, we show that consumers, even if they knew the uses to which this type of personal information were being put, lack effective means to control the use of this type of data. The standard tool of notice-and-choice has well known problems, including the user’s lack of information with which to make a choice; and then, even if the user had sufficient information, doing so is not practical.49 These are greatly exacerbated by the nature of the interchanges for communications metadata and telemetry information. Each new transmission—each click on an internal link on a webpage, for example—may carry different implications for a user in terms of privacy. The current regimen, notice-and-choice, presents a completely unworkable set of requests for a user, who could well be responding many times a minute regarding whether to allow the use of metadata beyond the purposes of content delivery and display. This is especially the case for telemetry, where the ability to understand both present and future use of the data provided from the sensors requires a deeper understanding of what information these devices can provide than anyone but a trained engineer would know. Third, while there has been academic and industry research on telemetry’s use, there has been little exploration of the policy and legal implications stemming from that use. We provide this factor, while at the same time addressing the closely related issues raised by industry’s use of communications metadata to track user interests and behavior 
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  2. In this paper, we examine private-sector collection and use of metadata and telemetry information and provide three main contributions: First, we lay out the extent to which “non-content”—the hidden parts of Internet communications (aspects the user does not explicitly enter) and telemetry—are highly revelatory of personal behavior. We show that, privacy policies notwithstanding, users rarely know that the metadata and telemetry information is being collected and almost never know the uses to which it is being put. Second, we show that consumers, even if they knew the uses to which this type of personal information were being put, lack effective means to control the use of this type of data. The standard tool of notice-and-choice has well known problems, including the user’s lack of information with which to make a choice; and then, even if the user had sufficient information, doing so is not practical.49 These are greatly exacerbated by the nature of the interchanges for communications metadata and telemetry information. Each new transmission—each click on an internal link on a webpage, for example—may carry different implications for a user in terms of privacy. The current regimen, notice-and-choice, presents a completely unworkable set of requests for a user, who could well be responding many times a minute regarding whether to allow the use of metadata beyond the purposes of content delivery and display. This is especially the case for telemetry, where the ability to understand both present and future use of the data provided from the sensors requires a deeper understanding of what information these devices can provide than anyone but a trained engineer would know. Third, while there has been academic and industry research on telemetry’s use, there has been little exploration of the policy and legal implications stemming from that use. We provide this factor, while at the same time addressing the closely related issues raised by industry’s use of communications metadata to track user interests and behavior. 
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  3. Smart homes are gaining popularity due to their convenience and efficiency, both of which come at the expense of increased complexity of Internet of Things (IoT) devices. Due to the number and heterogeneity of IoT devices, technologically inexperienced or time-burdened residents are unlikely to manage the setup and maintenance of IoT apps and devices. We highlight the need for a "HandyTech": a technically skilled contractor who can set up, repair, debug, monitor, and troubleshoot home IoT systems. In this paper, we consider the potential privacy challenges posed by the HandyTech, who has the ability to access IoT devices and private data. We do so in the context of single and multi-user smart homes, including rental units, condominiums, and temporary guests or workers. We examine the privacy harms that can arise when a HandyTech has legitimate access to information, but uses it in unintended ways. By providing insights for the development of privacy control policies and measures in-home IoT environments in the presence of the HandyTech, we capture the privacy concerns raised by other visitors to the home, including temporary residents, part-time workers, etc. This helps lay a foundation for the broad set of privacy concerns raised by home IoT systems. 
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  4. Use of smartphone-based digital contact- tracing apps has shown promise in responding to the COVID-19 pandemic. But such apps can reveal very personal information; thus, their use raises important societal questions, not just during the current pandemic but as we learn and prepare for other inevitable outbreaks ahead. Can privacy-protective versions of such apps work? Are they efficacious? Because the apps influence who is notified of exposure and who gets tested—and possibly treated—we need to consider the apps in the context of health care equity. Exposure-notification apps are predicated on the assumption that if someone is informed of exposure, they will follow instructions to isolate. Such an expectation fails to take into account that isolation—and sometimes even seeking care when ill—is much harder for some populations than others. If apps are to work for all, and not make this worse for disadvantaged populations, there needs to be basic social infrastructure that supports testing, contact tracing, and isolation. 
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  5. Stobert, Elizabeth; Spring, Jonathan (Ed.)
    Communications metadata can be used to determine a communication’s device, identify the user of the device, and profile the user’s personality and behavior. The current state of affairs is that the increase of attacks against user privacy based on using communications metadata vastly outpaces the ability of users to protect themselves. With few exceptions, protections are point solutions against a specific attack. In the current situation, the user loses. This paper is an initial step in a multi-step research effort to reset that balance. The main contribution of this paper is a categorization of the uses of communications metadata based on their privacy impact. Because of the technical complexity of the problem, including the wide variety of electronic communications, technology can only go so far in providing solutions to the privacy problems created by the use of communications metadata. Legal and policy intervention will also be needed. This categorization is intended to provide a start in developing legal and policy privacy protections for communications metadata. Along the way, I also provide an explanation for how it is that communications metadata has become so valuable, sometimes surpassing the value of content. This work provides both an intellectual framework for thinking about the privacy implications of the use of communications metadata and a roadmap, with first steps taken, for providing privacy protections for users of electronic communications. 
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  6. Brain age (BA), distinct from chronological age (CA), can be estimated from MRIs to evaluate neuroanatomic aging in cognitively normal (CN) individuals. BA, however, is a cross-sectional measure that summarizes cumulative neuroanatomic aging since birth. Thus, it conveys poorly recent or contemporaneous aging trends, which can be better quantified by the (temporal) pace P of brain aging. Many approaches to map P, however, rely on quantifying DNA methylation in whole-blood cells, which the blood–brain barrier separates from neural brain cells. We introduce a three-dimensional convolutional neural network (3D-CNN) to estimate P noninvasively from longitudinal MRI. Our longitudinal model (LM) is trained on MRIs from 2,055 CN adults, validated in 1,304 CN adults, and further applied to an independent cohort of 104 CN adults and 140 patients with Alzheimer’s disease (AD). In its test set, the LM computes P with a mean absolute error (MAE) of 0.16 y (7% mean error). This significantly outperforms the most accurate cross-sectional model, whose MAE of 1.85 y has 83% error. By synergizing the LM with an interpretable CNN saliency approach, we map anatomic variations in regional brain aging rates that differ according to sex, decade of life, and neurocognitive status. LM estimates of P are significantly associated with changes in cognitive functioning across domains. This underscores the LM’s ability to estimate P in a way that captures the relationship between neuroanatomic and neurocognitive aging. This research complements existing strategies for AD risk assessment that estimate individuals’ rates of adverse cognitive change with age. 
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    Free, publicly-accessible full text available March 11, 2026
  7. The gap between chronological age (CA) and biological brain age, as estimated from magnetic resonance images (MRIs), reflects how individual patterns of neuroanatomic aging deviate from their typical trajectories. MRI-derived brain age (BA) estimates are often obtained using deep learning models that may perform relatively poorly on new data or that lack neuroanatomic interpretability. This study introduces a convolutional neural network (CNN) to estimate BA after training on the MRIs of 4,681 cognitively normal (CN) participants and testing on 1,170 CN participants from an independent sample. BA estimation errors are notably lower than those of previous studies. At both individual and cohort levels, the CNN provides detailed anatomic maps of brain aging patterns that reveal sex dimorphisms and neurocognitive trajectories in adults with mild cognitive impairment (MCI, N  = 351) and Alzheimer’s disease (AD, N  = 359). In individuals with MCI (54% of whom were diagnosed with dementia within 10.9 y from MRI acquisition), BA is significantly better than CA in capturing dementia symptom severity, functional disability, and executive function. Profiles of sex dimorphism and lateralization in brain aging also map onto patterns of neuroanatomic change that reflect cognitive decline. Significant associations between BA and neurocognitive measures suggest that the proposed framework can map, systematically, the relationship between aging-related neuroanatomy changes in CN individuals and in participants with MCI or AD. Early identification of such neuroanatomy changes can help to screen individuals according to their AD risk. 
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