scholarly journals Experimental Evaluation of Advertisement-Based Bluetooth Low Energy Communication

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 107 ◽  
Author(s):  
Maciej Nikodem ◽  
Marek Bawiec

This paper addresses the efficiency of Bluetooth Low Energy (BLE) communication in a network composed of a large number of tags that transmit information to a single hub using advertisement mode. Theoretical results show that the use of advertisements enables hundreds and thousands of BLE devices to coexist in the same area and at the same time effectively transmit messages. Together with other properties (low power consumption, medium communication range, capability to detect a signal’s angle-of-arrival, etc.), this makes BLE a competing technology for the Internet of Things (IoT) applications. However, as the number of communicating devices increases, the advertisement collision intensifies and the communication performance of BLE drops. This phenomena was so far analyzed theoretically, in simulations and in small-scale experiments, but large-scale experiments are not presented in the literature. This paper complements previous results and presents an experimental evaluation of a real IoT-use case, which is the deployment of over 200 tags communicating using advertisements. We evaluate the impact of the number of advertisements on the effective data reception rate and throughput. Despite the advertisement collision rate in our experiment varying between 0.22 and 0.33, we show that BLE, thanks to the multiple transmission of advertisements, can still ensure acceptable data reception rates and fulfill the requirements of a wide range of IoT applications.

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6371
Author(s):  
Maciej Nikodem ◽  
Mariusz Slabicki ◽  
Marek Bawiec

The use of Bluetooth Low Energy (BLE) in the Internet-of-Things (IoT) applications has become widespread and popular. This has resulted in the increased number of deployed BLE devices. To ensure energy efficiency, applications use connectionless communication where nodes broadcast information using advertisement messages. As the BLE devices compete for access to spectrum, collisions are inevitable and methods that improve device coexistence are required. This paper proposes a connectionless communication scheme for BLE that improves communication efficiency in IoT applications where a large number of BLE nodes operate in the same area and communicate simultaneously to a central server. The proposed scheme is based on an active scanning mode and is compared with a typical application where passive scanning mode is used. The evaluation is based on numerical simulations and real-life evaluation of a network containing 150 devices. The presented scheme significantly reduces the number of messages transmitted by each node and decreases packet loss ratio. It also improves the energy efficiency and preserves the battery of BLE nodes as they transmit fewer radio messages and effectively spent less time actively communicating. The proposed connectionless BLE communication scheme can be applied to a large variety of IoT applications improving their performance and coexistence with other devices operating in the 2.4 GHz band. Additionally, the implementation complexity and costs of the proposed communication scheme are negligible.


Bluetooth Low Energy or BLE is a technology targeting mostly small-scale IoT applications including wearables and broadcasting beacons that require devices to send small amounts of data using minimal power. This paper focuses on our implementation, which is a system, designed to filter RSSI (Received Signal Strength Indicator), calculate the co-ordinates of a BLE device that is programmed as a Beacon and display the coordinates. Since RSSI is susceptible to noise and a downgrade in its reliability is unavoidable, several filtration methods have been used. The ‘Kalman – Histogram’ method, which incorporates the usage of a histogram of the RSSI readings along with the Kalman filter, is our own approach to tackle issues regarding noisy RSSI readings. The localization of stationary ‘Assets’, has been evaluated using the Trilateration algorithm: a result in mathematics which is used to locate a single point using its distance from three or more other points. The purpose of this research work is to provide a comparative result analysis of the results obtained using the aforementioned filters, indicating the effect of these filters on our localization system. As our research suggests, the ‘Kalman – Histogram’ filter performs better as compared to other filters and can be used in localization applications for better accuracy.


2018 ◽  
Vol 12 (1) ◽  
pp. 151-170
Author(s):  
Hannah Vandegrift Eldridge

Abstract In recent years, theories of rhythm have been proposed by a number of different disciplines, including historical poetics, generative metrics, cognitive literary studies, and evolutionary aesthetics. The wide range of fields indicates the transdisciplinary nature of rhythm as a phenomenon, as well as its complexity, highlighting the degree to which many of the central questions surrounding rhythm remain extraordinarily difficult even to state in terms that can traverse the disciplinary boundaries effortlessly transgressed by rhythm as a phenomenon. In particular, any theory of rhythm, whether in music, dance, sociology, or language, must grapple with two quandaries. First, the precise site of rhythm remains opaque: rhythms occur in, affect, and are produced by all of bodies, cultures, and universals (whether metaphysical or species-physiological). What is the relation between species-wide characteristic, individual body, cultural context, and the history of art making in the experience of rhythm? Second, rhythm is simultaneously a phenomenon of fixed, organizing form and one of dynamic, changing flow. How can rhythm encompass both the measurement of regular recurrences across time and the organizing of temporal phenomena as they unfold? In this article, I draw on Emile Benveniste and Henri Meschonnic to elucidate these quandaries or conflicts before turning to Friedrich Nietzsche’s work on rhythm. I argue that Nietzsche’s work with rhythm provides a historically situated model for how we might continue to take the questions and conflicts within rhythm seriously, rather than privileging an abstract and universally applicable theory of rhythm. This model is especially crucial for our own historical moment, when cultural-political emphasis on science and technology at the expense of aesthetics devalues all insights not presented in the form of countable data points or empirically testable facts. Nietzsche is, of course, one of the great critics of positivist-scientistic epistemologies, part of a long tradition questioning the naturalness of natural-scientific paradigms and alerting us to the metaphors at play even in the ›hard sciences‹. I use rhythm as one paradigmatic place to resist the importation of scientistic thought into discussions of language, literature, and culture. I show how Nietzsche’s writings on rhythm prove illuminating for contemporary understandings of rhythm because the tensions in his work are shaped by the quandaries inherent to rhythm that I have used Benveniste and Meschonnic to elaborate, namely the question of rhythm’s site as individual, cultural, or universal, and the conflict between rhythm as form and as flow. The question of the site of rhythm appears in Nietzsche’s discussions of Greek and Latin meters both in his philological works, in his aphorisms, and in his letters: on the one hand, he argues that Greek and Latin metrical and rhythmic resources are irrevocably lost to modern cultures (indicating that rhythm is a product of culture), while on the other, he emphasizes the impact of rhythm on the body and offers advice for replicating Ancient metrical and rhythmic techniques (suggesting that rhythm is based on physiological universals). And the conflict between flow and form appears as Nietzsche praises both the productive constraint created by large-scale, architectonic, or macro-formal rhythms and the freedom from such constraint enabled by small-scale, leitmotiv-based, or micro-formal rhythms. The conflicts in Nietzsche’s work between the loss and recovery of Ancient rhythms and between rhythm as small scale freedom vs. large scale constraint thus represent one particular unfolding of the dilemmas for rhythmical theory worked out by Benveniste and Meschonnic. The various modern disciplines engaged with rhythm will answer different sets of these questions in different ways. Most practitioners of, e. g., evolutionary aesthetics, neuroaesthetics, or cognitive poetics would no doubt contend that they are using the tools of the natural sciences to investigate long-standing humanistic inquiries. Nietzsche, as a critic of his own era’s scientific positivism who allows tensions inherent in these questions to remain open in his own work, is an ideal interlocutor with whom to ask whether even the adoption of these tools ends up placing excessive faith in natural-scientific paradigms and undercutting other—affective, bodily, metaphorical, poetic, etc.—ways of knowing, as I demonstrate briefly in the examples of evolutionary aesthetics and generative metrics. Because Nietzsche leaves open the conflicts over rhythm’s site and its qualities as form or flow, he can use individual bodily experience to make physiological arguments about the effects of rhythm on culture and vice versa: Nietzsche takes his bodily response to be an index of cultural values inherent to rhythmical practices. The particular values that Nietzsche critiques shift across his career—early on he condemns German musical and poetic rhythms for being too rigid, while later he sees them as pathologically heightening affect and emotion. In both cases, detrimental rhythmic practices lead to detrimental bodily practices and to the degeneration of culture, while rhythmic practices work as a bodily and cultural corrective. In his critiques of German forms and praises of Greek forms, and in the moments in which he brings them together, Nietzsche thus asserts the complex interrelation of culture, body, and history.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2257
Author(s):  
Bozheng Pang ◽  
Kristof T’Jonck ◽  
Tim Claeys ◽  
Davy Pissoort ◽  
Hans Hallez ◽  
...  

Bluetooth Low Energy (BLE) is a popular wireless communication protocol heavily used in Internet of Things applications. Nowadays, robustness is considered a key requirement in wireless communication. However, radio interference from various sources may affect the performance of BLE devices, leading to channel congestion. Therefore, there is a broadly recognized need of methodologies capable of sensing and avoiding interference. In this paper, two improvements at the data link layer for interference detection and channel selection are proposed to enhance the BLE connection robustness. This paper also presents a wide range of experimental evaluations aiming at validating the improvements and providing insights on both these improvements. Particularly, the communication performance of the BLE link layer is assessed in terms of channel usage distribution, supervision timeout ratio (STR) and packet loss rate (PLR) under different interference environments. Results from these experiments (reliability over 97% and 99% under two different harsh environments) highlight the effects of both improvements on the BLE robustness. Meanwhile, the authority of scheduling the whole mechanism is given to the link layer and even the higher application layer. This paper provides a set of solutions for BLE confronting interference in link layer.


2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.


2018 ◽  
Vol 76 (4) ◽  
pp. 1122-1130 ◽  
Author(s):  
Lotta Clara Kluger ◽  
Sophia Kochalski ◽  
Arturo Aguirre-Velarde ◽  
Ivonne Vivar ◽  
Matthias Wolff

Abstract In February and March 2017, a coastal El Niño caused extraordinary heavy rains and a rise in water temperatures along the coast of northern Peru. In this work, we document the impacts of this phenomenon on the artisanal fisheries and the scallop aquaculture sector, both of which represent important socio-economic activities for the province of Sechura. Despite the perceived absence of effective disaster management and rehabilitation policies, resource users opted for a wide range of different adaptation strategies and are currently striving towards recovery. One year after the event, the artisanal fisheries fleet has returned to operating almost on a normal scale, while the aquaculture sector is still drastically impacted, with many people continuing to work in different economic sectors and even in other regions of the country. Recovery of the social-ecological system of Sechura likely depends on the occurrence of scallop seed and the financial capacity of small-scale producers to reinitiate scallop cultures. Long-term consequences of this coastal El Niño are yet to be studied, though the need to develop trans-local and trans-sectoral management strategies for coping with disturbance events of this scale is emphasized.


2017 ◽  
Vol 10 (3) ◽  
pp. 1383-1402 ◽  
Author(s):  
Paolo Davini ◽  
Jost von Hardenberg ◽  
Susanna Corti ◽  
Hannah M. Christensen ◽  
Stephan Juricke ◽  
...  

Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate – specifically the Madden–Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).


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