This paper presents PLoRa, an ambient backscatter design that enables long-range wireless connectivity for batteryless IoT devices. PLoRa takes LoRa transmissions as the excitation signals, conveys data by modulating signal into a new standard "chirp" signal, and shifts this to different channel be received at gateway faraway. achieves holistic RF front-end hardware software design, including low-power packet detection circuit, blind chirp modulation algorithm energy management circuit. To...

Device-free localization of people and objects indoors not equipped with radios is playing a critical role in many emerging applications. This paper presents an accurate model-based device-free system LiFS, implemented on cheap commercial off-the-shelf (COTS) Wi-Fi devices. Unlike previous COTS device-based work, LiFS able to localize target accurately without offline training. The basic idea simple: channel state information (CSI) sensitive target's location by modelling the CSI...

This paper presents FUNDED (Flow-sensitive vUl-Nerability coDE Detection), a novel learning framework for building vulnerability detection models. Funded leverages the advances in graph neural networks (GNNs) to develop graph-based method capture and reason about program's control, data, call dependencies. Unlike prior work that treats program as sequential sequence or an untyped graph, learns operates on representation of source code, which individual statements are connected other through...

We present CrossSense, a novel system for scaling up WiFi sensing to new environments and larger problems. To reduce the cost of model training data collection, CrossSense employs machine learning train, off-line, roaming that generates from one set measurements synthetic samples each target environment. scale problem size, adopts mixture-of-experts approach where multiple specialized models, or experts, are used capture mapping diverse inputs desired outputs. The experts trained offline at...

Target imaging and material identification play an important role in many real-life applications. This paper introduces TagScan, a system that can identify the type image horizontal cut of target simultaneously with cheap commercial off the-shelf (COTS) RFID devices. The key intuition is different materials sizes cause amounts phase RSS (Received Signal Strength) changes when radio frequency (RF) signal penetrates through target. Multiple challenges need to be addressed before we turn idea...

Passive localization is fundamental for many applications such as activity monitoring and real-time tracking. Existing received signal strength (RSS)-based passive approaches have been proposed in the literature, which depend on dense deployment of wireless communication nodes to achieve high accuracy. Thus, they are not cost-effective scalable. This paper proposes RSS distribution-based (RDL) technique, can accuracy without deployment. In essence, RDL leverages diffraction theory enable...

Despite several attacks have been proposed, text-based CAPTCHAs are still being widely used as a security mechanism. One of the reasons for pervasive use text captchas is that many prior scheme-specific and require labor-intensive time-consuming process to construct. This means change in captcha features like noisier background can simply invalid an earlier attack. paper presents generic, yet effective solver based on generative adversarial network. Unlike machine-learning-based approaches...

Pattern lock is widely used as a mechanism for authentication and authorization on Android devices.This paper presents novel video-based attack to reconstruct patterns from video footage filmed using mobile phone camera.Unlike prior attacks pattern lock, our approach does not require the capture any content displayed screen.Instead, we employ computer vision algorithm track fingertip movements infer pattern.Using geometry information extracted tracked motions, able accurately identify small...

Device-free localization, which does not require any device attached to the target, is playing a critical role in many applications, such as intrusion detection, elderly monitoring and so on. This paper introduces D-Watch, device-free system built on top of low cost commodity-off-the-shelf RFID hardware. Unlike previous works consider multipaths detrimental, D-Watch leverages "bad" provide decimeter-level localization accuracy without offline training. harnesses angle-of-arrival information...

Device-free localization (DFL), which does not require any devices to be attached target(s), has become an appealing technology for many applications, such as intrusion detection and elderly monitoring. To achieve high accuracy, most recent DFL methods rely on collecting a large number of received signal strength (RSS) changes distorted by target(s). Consequently, the incurred energy consumption renders them infeasible resource-constraint networks, wireless sensor networks. This paper...

Material sensing is an essential ingredient for many IoT applications. While hyperspectral camera, infrared, X-Ray, and Radar provide potential solutions material identification, high cost the major concern limiting their In this paper, we explore capability of employing RF signals fine-grained with commodity RFID device. The key reason our system to work that tag antenna's impedance changed when it close or attached a target. amount change dependent on target's type, thus enabling us...

Device-free localization of objects not equipped with RF radios is playing a critical role in many applications. This paper presents LIFS, Low human-effort, device-free system fine-grained subcarrier information, which can localize target accurately without offline training. The basic idea simple: channel state information (CSI) sensitive to target's location and thus the be localized by modelling CSI measurements multiple wireless links. However, due rich multipath indoors, easily modelled....

Contactless wireless sensing without attaching a device to the target has achieved promising progress in recent years. However, one severe limitation is small range. This paper presents WideSee realize wide-area with only transceiver pair. utilizes LoRa signal achieve larger range of and further incorporates drone's mobility broaden area. solutions across software hardware overcome two aspects challenges for wide-range contactless sensing: (i) interference brought by LoRa's high sensitivity;...

With parallel decoding for backscatter communication, tags are allowed to transmit concurrently and more efficiently. Existing mechanisms, however, assume that signals of the highly stable and, hence, may not perform optimally in naturally dynamic systems. This paper introduces FlipTracer, a practical system achieves reliable even hostile channel conditions. FlipTracer is designed with key insight; although collided signal time-varying irregular, transitions between signals' combined states...

JavaScript (JS) is a popular, platform-independent programming language. To ensure the interoperability of JS programs across different platforms, implementation engine should conform to ECMAScript standard. However, doing so challenging as there are many subtle definitions API behaviors, and keep evolving.

Background Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, with a significant global burden. This study evaluates global, regional, and national trends in prevalence, mortality, disability-adjusted life years (DALYs) of childhood ALL from 1990 to 2021, providing insights into disparities progress across different socio-demographic geographic contexts. Methods Data were sourced Global Burden Disease study. Trends DALYs analyzed by index (SDI) regions, areas, countries....

Without relying on devices carried by the target, device-free localization (DFL) is attractive for many applications, such as wildlife monitoring. There still exist challenges DFL multiple targets without dense deployment of sensor nodes. To fit gap, in this paper, we propose a multi-target method based compressive sensing, named LCS. The key observation that given pair nodes, received signal strength (RSS) will be different when target locates at locations. Taking advantage sensing sparse...

Device-free localization (DFL) plays an important role in many applications, such as wildlife population and migration tracking. Most of current DFL systems leverage the distorted received signal strength (RSS) changes to localize target(s). However, they assume a fixed distribution RSS change measurements, although are by different types targets. It inevitably causes fail if targets for modeling testing belong categories. This paper presents TLCS-a transferring compressive sensing based...

Sleep is an important part of our daily routine -- we spend about one-third time doing it. By tracking sleep-related events and activities, sleep monitoring provides decision support to help us understand quality causes poor sleep. Wearable devices provide a new way for monitoring, allowing monitor from the comfort own home. However, existing solutions do not take full advantage rich sensor data provided by these devices. In this paper, present design development SleepGuard, novel approach...

Many emerging applications driven the fast development of device-free localization (DfL) technique, which does not require target to carry any wireless devices. Most current DfL approaches have two main drawbacks in practical applications. First, as pre-calibrated received signal strength (RSS) each location (i.e., radio-map) a specific area cannot be directly applied new areas, manual calibration for different areas will lead high human effort cost. Second, large number RSS are needed...

Pattern lock is widely used for identification and authentication on Android devices. This article presents a novel video-based side channel attack that can reconstruct locking patterns from video footage filmed using smartphone. As departure previous attacks pattern lock, this new does not require the camera to capture any content displayed screen. Instead, it employs computer vision algorithm track fingertip movement trajectory infer pattern. Using geometry information extracted tracked...

Target material identification is playing an important role in our everyday life. Traditional camera and video-based methods bring severe privacy concerns. In the last few years, while RF signals have been exploited for indoor localization, gesture recognition motion tracking, very little attention has paid identification. This paper introduces WiMi, a device-free target system, implemented on ubiquitous cheap commercial off-the-shelf (COTS) Wi-Fi devices. The intuition that different...

With parallel decoding for backscatter communication, tags are allowed to transmit concurrently and more efficiently. Existing mechanisms, however, assume that signals of the highly stable, hence may not perform optimally in naturally dynamic systems. This paper introduces FlipTracer, a practical system achieves reliable even hostile channel conditions. FlipTracer is designed with key insight: although collided signal time-varying irregular, transitions between signals' combined states...