355 research outputs found

    Noisy Beeping Networks

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    We introduce noisy beeping networks, where nodes have limited communication capabilities, namely, they can only emit energy or sense the channel for energy. Furthermore, imperfections may cause devices to malfunction with some fixed probability when sensing the channel, which amounts to deducing a noisy received transmission. Such noisy networks have implications for ultra-lightweight sensor networks and biological systems. We show how to compute tasks in a noise-resilient manner over noisy beeping networks of arbitrary structure. In particular, we transform any algorithm that assumes a noiseless beeping network (of size nn) into a noise-resilient version while incurring a multiplicative overhead of only O(log⁡n)O(\log n) in its round complexity, with high probability. We show that our coding is optimal for some tasks, such as node-coloring of a clique. We further show how to simulate a large family of algorithms designed for distributed networks in the CONGEST(BB) model over a noisy beeping network. The simulation succeeds with high probability and incurs an asymptotic multiplicative overhead of O(B⋅Δ⋅min⁡(n,Δ2))O(B\cdot \Delta \cdot \min(n,\Delta^2)) in the round complexity, where Δ\Delta is the maximal degree of the network. The overhead is tight for certain graphs, e.g., a clique. Further, this simulation implies a constant overhead coding for constant-degree networks

    Optimal Message-Passing with Noisy Beeps

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    Beeping models are models for networks of weak devices, such as sensor networks or biological networks. In these networks, nodes are allowed to communicate only via emitting beeps: unary pulses of energy. Listening nodes only the capability of carrier sensing: they can only distinguish between the presence or absence of a beep, but receive no other information. The noisy beeping model further assumes listening nodes may be disrupted by random noise. Despite this extremely restrictive communication model, it transpires that complex distributed tasks can still be performed by such networks. In this paper we provide an optimal procedure for simulating general message passing in the beeping and noisy beeping models. We show that a round of Broadcast CONGEST can be simulated in O(Δ log n) round of the noisy (or noiseless) beeping model, and a round of CONGEST can be simulated in O(Δ2 log n) rounds (where Δ is the maximum degree of the network). We also prove lower bounds demonstrating that no simulation can use asymptotically fewer rounds. This allows a host of graph algorithms to be efficiently implemented in beeping models. As an example, we present an O(log n)-round Broadcast CONGEST algorithm for maximal matching, which, when simulated using our method, immediately implies a near-optimal O(Δ log2 n)-round maximal matching algorithm in the noisy beeping model

    Noisy Radio Network Lower Bounds via Noiseless Beeping Lower Bounds

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    Beeping Shortest Paths via Hypergraph Bipartite Decomposition

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    Contention Resolution Without Collision Detection: Constant Throughput And Logarithmic Energy

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    Combining Wireless Sensor Networks and Semantic Middleware for an Internet of Things-Based Sportsman/Woman Monitoring Application.

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    Wireless Sensor Networks (WSNs) are spearheading the efforts taken to build and deploy systems aiming to accomplish the ultimate objectives of the Internet of Things. Due to the sensors WSNs nodes are provided with, and to their ubiquity and pervasive capabilities, these networks become extremely suitable for many applications that so-called conventional cabled or wireless networks are unable to handle. One of these still underdeveloped applications is monitoring physical parameters on a person. This is an especially interesting application regarding their age or activity, for any detected hazardous parameter can be notified not only to the monitored person as a warning, but also to any third party that may be helpful under critical circumstances, such as relatives or healthcare centers. We propose a system built to monitor a sportsman/woman during a workout session or performing a sport-related indoor activity. Sensors have been deployed by means of several nodes acting as the nodes of a WSN, along with a semantic middleware development used for hardware complexity abstraction purposes. The data extracted from the environment, combined with the information obtained from the user, will compose the basis of the services that can be obtained

    Generic Personal Safety Applications; empowering victims of Domestic Violence and Abuse? A Practitioner Lens

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Bespoke and generic Domestic Violence and Abuse (DVA) Personal Safety Applications (PSAs) have become a popular choice for strategic crime prevention projects by those in the criminal justice sector; to achieve justice through digital means as part of the wider digital justice project. These PSAs have been heralded as tools for the protection, empowerment, and resilience building of victims in DVA, despite limited independent evaluations. This article explores the use of a generic PSA, which the police have adopted for rollout to victims of DVA in one region of the United Kingdom. We undertook a thematic analysis of data taken from a roundtable and three follow up focus groups with practitioners from the police, criminal justice, DVA specialist sector, and victim services, alongside the PSA development team. We found both some support for using this PSA and serious concerns regarding its use in DVA situations

    Black Girls Speak STEM: Counterstories of Informal and Formal Learning Experiences

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    This study presents the interpretations and perceptions of Black girls who participated in I AM STEM – a community-based informal science, technology, engineering, and mathematics (STEM) program. Using narrative inquiry, participants generated detailed accounts of their informal and formal STEM learning experiences. Critical race methodology informed this research to portray the dynamic and complex experiences of girls of color, whose stories have historically been silenced and misrepresented. The data sources for this qualitative study included individual interviews, student reflection journals, samples of student work, and researcher memos, which were triangulated to produce six robust counterstories. Excerpts of the counterstories are presented in this article. The major findings of this research revealed that I AM STEM ignited an interest in STEM learning through field trips and direct engagement in scientific phenomena that allowed the girls to become agentic in continuing their engagement in STEM activities throughout the year. This call to awaken the voices of Black girls to speak casts light on their experiences and challenges as STEM learners ⎯ from their perspectives. The findings confirm that when credence and counterspaces are given to Black girls, they are poised to reveal their luster toward STEM learning. This study provided a space for Black girls to reflect on their STEM learning experiences, formulate new understandings, and make connections between the informal and formal learning environments within the context of their everyday lives, thus offering a more holistic approach to STEM learning that occurs across settings and over a lifetime

    Radio network algorithms for global communication

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    Radio networks are a distributed computing model capturing the behavior of devices that communicate via wireless transmissions. Applications of wireless networks have expanded hugely in recent decades due to their convenience and versatility. However, wireless communication presents practical difficulties, particularly in avoiding interference between transmissions. The radio network model provides a theoretical distillation of the behavior of such networks, in order to better understand and facilitate communication. This thesis concerns fundamental global communication tasks in the radio network model: that is, tasks that require relaying messages throughout the entire network. Examples include broadcasting a message to all devices in a network, or reaching agreement on a single device to act as a coordinator. We present algorithms to perform global tasks efficiently, and show improved asymptotic running times over a range of environments and model variants. Our results demonstrate an advance over the state of the art in radio network research, and in many cases reach or approach known lower bounds
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