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Creators/Authors contains: "Kotz, David"

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  1. Smart-home technology is now pervasive, demanding increased attention to the security of the devices and the privacy of the home's residents. To assist residents in making security and privacy decisions - e.g., whether to allow a new device to connect to the network, or whether to be alarmed when an unknown device is discovered - it helps to know whether the device is inside the home, or outside. In this paper we present MOAT, a system that leverages Wi-Fi sniffers to analyze the physical properties of a device's wireless transmissions to infer whether that device is located inside or outside of a home. MOAT can adaptively self-update to accommodate changes in the home indoor environment to ensure robust long-term performance. Notably, MOAT does not require prior knowledge of the home's layout or cooperation from target devices, and is easy to install and configure. We evaluated MOAT in four different homes with 21 diverse commercial smart devices and achieved an overall balanced accuracy rate of up to 95.6%. Our novel periodic adaptation technique allowed our approach to maintain high accuracy even after rearranging furniture in the home. MOAT is a practical and efficient first step for monitoring and managing devices in a smart home. 
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    Free, publicly-accessible full text available November 21, 2025
  2. This paper analyzes Google Home, Apple HomeKit, Samsung SmartThings, and Amazon Alexa platforms, focusing on their integration with the Matter protocol. Matter is a connectivity standard developed by the Connectivity Standards Alliance (CSA) for the smart-home industry. By examining key features and qualitative metrics, this study aims to provide valuable insights for consumers and industry professionals in making informed decisions about smart-home devices. We conducted (from May to August 2024) a comparative analysis to explore how Google Home Nest, Apple HomePod Mini, Samsung SmartThings station, and Amazon Echo Dot platforms leverage the power of Matter to provide seamless and integrated smart-home experiences. 
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    Free, publicly-accessible full text available January 10, 2026
  3. In this article, we outline the challenges associated with the widespread adoption of smart devices in homes. These challenges are primarily driven by scale and device heterogeneity: a home may soon include dozens or hundreds of devices, across many device types, and may include multiple residents and other stakeholders. We develop a framework for reasoning about these challenges based on the deployment, operation, and decommissioning life cycle stages of smart devices within a smart home. We evaluate the challenges in each stage using the well- known CIA triad—Confidentiality, Integrity, and Availability. In addition, we highlight open research questions at each stage. Further, we evaluate solutions from Apple and Google using our framework and find notable shortcomings in these products. Finally, we sketch some preliminary thoughts on a solution for the smart home of the near future. 
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  4. Harmonic radar systems have been shown to be an effective method for detecting the presence of electronic devices, even if the devices are powered off. Prior work has focused on detecting specific non-linear electrical components (such as transistors and diodes) that are present in any electronic device. In this paper we show that harmonic radar is also capable of detecting the presence of batteries. We tested a proof-of-concept system on Alkaline, NiMH, Li-ion, and Li-metal batteries. With the exception of Li-metal coin cells, the prototype harmonic radar detected the presence of batteries in our experiments with 100% accuracy. 
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  5. Smart-home devices have become integral to daily routines, but their onboarding procedures - setting up a newly acquired smart device into operational mode - remain understudied. The heterogeneity of smart-home devices and their onboarding procedure can easily overwhelm users when they scale up their smart-home system. While Matter, the new IoT standard, aims to unify the smart-home ecosystem, it is still evolving, resulting in mixed compliance among devices. In this paper, we study the complexity of device onboarding from users' perspectives. We thus performed cognitive walkthroughs on 12 commercially available smart-home devices, documenting the commonality and distinctions of the onboarding process across these devices. We found that onboarding smart home devices can often be tedious and confusing. Users must devote significant time to creating an account, searching for the target device, and providing Wi-Fi credentials for each device they install. Matter-compatible devices are supposedly easier to manage, as they can be registered through one single hub independent of the vendor. Unfortunately, we found such a statement is not always true. Some devices still need their own companion apps and accounts to fully function. Based on our observations, we give recommendations about how to support a more user-friendly onboarding process. 
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  6. A key feature of smart home devices is monitoring the environment and recording data. These devices provide security via motion-detection video alerts, cost-savings via thermostat usage history, and peace of mind via functions like auto-locking doors or water leak detectors. At the same time, the sharing of this information in interpersonal relationships---though necessary---is currently accomplished on an all-or-nothing basis. This can easily lead to oversharing in a multi-user environment. Although prior work has studied people's perceptions of information sharing with vendors or ISPs, the sharing of household data among users who interact personally is less well understood. Interpersonal situations make data sharing much more context-based and, thus, more complicated. In this paper, we use themes from the theory of contextual integrity in an online survey (n=1,992) to study how people perceive data sharing with others in smart homes and inform future designs and research. Our results show that data recipients in a smart home can be reduced to three major groups, and data types matter more than device types. We also found that the types of access control desired by users can vary from scenario to scenario. Depending on whom they are sharing data with and about what data, participants expressed varying levels of comfort when presented with different types of access control (e.g., explicit approval versus time-limited access). Taken together, this provides strong evidence that a more dynamic access control system is needed, and we can design it in a more usable way. 
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  7. With the availability of Internet of Things (IoT) devices offering varied services, smart home environments have seen widespread adoption in the last two decades. Protecting privacy in these environments becomes an important problem because IoT devices may collect information about the home’s occupants without their knowledge or consent. Furthermore, a large number of devices in the home, each collecting small amounts of data, may, in aggregate, reveal non-obvious attributes about the home occupants. A first step towards addressing privacy is discovering what devices are present in the home. In this paper, we formally define device discovery in smart homes and identify the features that constitute discovery in that environment. Then, we propose an evaluative rubric that rates smart home technology initiatives on their device discovery capabilities and use it to evaluate four commonly deployed technologies. We find none cover all device discovery aspects. We conclude by proposing a combined technology solution that provides comprehensive device discovery tailored to smart homes. 
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  8. With 'smart' technology becoming more prevalent in homes, computing is increasingly embedded into everyday life. The benefits are well-advertised, but the risks associated with these technologies are not as clearly articulated. We aim to address this gap by educating community members on some of these risks, and providing actionable advice to mitigate risks. To this end, we describe our efforts to design and implement a hands-on workshop for the public on smart-home security and privacy. Our workshop curriculum centers on the smart-home device lifecycle: obtaining, installing, using, and removing devices in a home. For each phase of the lifecycle, we present possible vulnerabilities along with preventative measures relevant to a general audience. We integrate a hands-on activity for participants to put best-practices into action throughout the presentation. We ran our workshop at a science museum in June 2023, and we used participant surveys to evaluate the effectiveness of our curriculum. Prior to the workshop, 38.8% of survey responses did not meet learning objectives, 22.4% partially met them, and 38.8% fully met them. After the workshop, only 9.2% of responses did not meet learning objectives, while 29.6% partially met them and 61.2% fully met them. Our experience shows that consumer-focused workshops can aid in bridging information gaps and are a promising form of outreach. 
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  9. Prior research has found that harmonic radar systems are able to detect the presence of electronic devices, even if the devices are powered off. These systems could be a powerful tool to help mitigate privacy invasions. For example, in a rental property devices such as cameras or microphones may be surreptitiously placed by a landlord to monitor renters without their knowledge or consent. A mobile harmonic radar system may be able to quickly scan the property and locate all electronic devices. The effective range of these systems for detecting consumer-grade electronics, however, has not been quantified. We address that shortcoming in this paper and evaluate a prototype harmonic radar system. We find the system, a variation of what has been proposed in the literature, is able to reliably detect some devices at a range of about two meters. We discuss the effect of hardware on the range of detection and propose an algorithm for automated detection. 
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