scholarly journals Framework for the Simulation of Sensor Networks Aimed at Evaluating In Situ Calibration Algorithms

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4577
Author(s):  
Florentin Delaine ◽  
Bérengère Lebental ◽  
Hervé Rivano
Keyword(s):  
Sensor Networks ◽  
Sensor Network ◽  
Low Cost ◽  
Test Case ◽  
Dense Networks ◽  
In Situ Calibration ◽  
Primary Test ◽  
The Impact

The drastically increasing availability of low-cost sensors for environmental monitoring has fostered a large interest in the literature. One particular challenge for such devices is the fast degradation over time of the quality of their data. Therefore, the instruments require frequent calibrations. Traditionally, this operation is carried out on each sensor in dedicated laboratories. This is not economically sustainable for dense networks of low-cost sensors. An alternative that has been investigated is in situ calibration: exploiting the properties of the sensor network, the instruments are calibrated while staying in the field and preferably without any physical intervention. The literature indicates there is wide variety of in situ calibration strategies depending on the type of sensor network deployed. However, there is a lack for a systematic benchmark of calibration algorithms. In this paper, we propose the first framework for the simulation of sensor networks enabling a systematic comparison of in situ calibration strategies with reproducibility, and scalability. We showcase it on a primary test case applied to several calibration strategies for blind and static sensor networks. The performances of calibration are shown to be tightly related to the deployment of the network itself, the parameters of the algorithm and the metrics used to evaluate the results. We study the impact of the main modelling choices and adjustments of parameters in our framework and highlight their influence on the results of the calibration algorithms. We also show how our framework can be used as a tool for the design of a network of low-cost sensors.

scholarly journals Charge critical sensors first: Minimize data loss in wireless rechargeable sensor networks

2018 ◽  
Vol 14 (7) ◽  
pp. 155014771878447
Author(s):  
Tong Li ◽  
Tang Liu ◽  
Jian Peng ◽  
Feng Lin ◽  
Wenzheng Xu
Keyword(s):  
Sensor Networks ◽  
Sensor Network ◽  
Large Scale ◽  
Base Station ◽  
The Novel ◽  
Monitoring Task ◽  
Wireless Rechargeable Sensor Networks ◽  
Alternative Routing ◽  
The Impact

In this article, we study the scheduling of a charging vehicle to replenish sensor energy in a large-scale wireless sensor network, by utilizing the novel wireless energy transfer technology. We note that existing studies do not treat different sensors in the network discriminatively and consider only how to charge as many sensors as possible before their energy expirations. However, there are some critical sensors in the network, so that many other sensors have no alternative routing paths to upload their sensing data to the base station if the critical sensors die. Therefore, the energy expiration of a critical sensor will result in that not only the sensor itself cannot continue its monitoring task, but also many other sensors cannot send their data during the dead period of the critical sensor. Then, the monitoring quality of the sensor network will significantly deteriorate due to the energy expirations of the critical sensor. Unlike existing studies, we take into account the impact of energy depletions of critical sensors and investigate a charging scheduling problem for sensor networks, which is to schedule a charging vehicle to replenish a set of to-be-charged sensors, such that not only the amount of lost data by dead sensors is minimized, but also the traveling cost of the vehicle for charging sensors is minimized, too. We then propose a novel algorithm for the problem. We finally compare the proposed algorithm with existing studies and simulation results show that the amount of lost data by the proposed algorithm is only about 50% of those by the existing studies, and the weighted sum of the amount of lost data and the vehicle travel distance is about 70% of those by the existing ones.

scholarly journals Performance metrics in wireless sensor networks :a survey and outlook

2018 ◽  
Vol 7 (2.26) ◽  
pp. 25
Author(s):  
E Ramya ◽  
R Gobinath
Keyword(s):  
Wireless Sensor Networks ◽  
Quality Of Service ◽  
Wireless Sensor Network ◽  
Sensor Networks ◽  
Sensor Network ◽  
Performance Metrics ◽  
Resource Constraints ◽  
Sensor Data ◽  
Wireless Sensor

Data mining plays an important role in analysis of data in modern sensor networks. A sensor network is greatly constrained by the various challenges facing a modern Wireless Sensor Network. This survey paper focuses on basic idea about the algorithms and measurements taken by the Researchers in the area of Wireless Sensor Network with Health Care. This survey also catego-ries various constraints in Wireless Body Area Sensor Networks data and finds the best suitable techniques for analysing the Sensor Data. Due to resource constraints and dynamic topology, the quality of service is facing a challenging issue in Wireless Sensor Networks. In this paper, we review the quality of service parameters with respect to protocols, algorithms and Simulations. 

scholarly journals Stability Assessment of Mining Excavations: the Impact of Large Depths

2018 ◽  
Vol 40 (3) ◽  
pp. 180-187
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Łukasz Bednarek
Keyword(s):  
Rock Mass ◽  
In Situ Monitoring ◽  
Stability Assessment ◽  
Underground Excavations ◽  
Deformation Prediction ◽  
Large Depth ◽  
Coal Deposits ◽  
The Impact

AbstractBack in the early 1980s, coal deposits occurring at depths of ~700 m below surface were already regarded as large-depth deposits. Meanwhile, today the borderline depth of large-depth mining has extended to >1,000 m. Design, excavation and maintenance of mining roadways at the depth of >1,000 m have, therefore, become crucial issues in a practical perspective in recent years. Hence, it is now extremely important to intensify research studies on the influence of large depths on the behaviour of rock mass and deformation of support in underground excavations. The paper presents the results of the study carried out in five mining excavations at depths ranging from 950 to 1,290 m, where monitoring stations with measurement equipment were built. The analysis of data from laboratory and coal mine tests, as well as in situ monitoring, helped to formulate a set of criteria for stability assessment of underground excavations situated at large depths. The proposed methodology of load and deformation prediction in support systems of the excavations unaffected by exploitation is based on the criteria referring to the depth of excavation and the quality of rock mass. The depth parameter is determined by checking whether the analysed excavation lies below the critical depth, whereas the rock mass quality is determined on the basis of the roof lithology index (WL) and the crack intensity factor (n)

scholarly journals SoC as IoT sensor network hub

2019 ◽  
Vol 12 (1) ◽  
pp. 42-45
Author(s):  
Alexandru Alexan ◽  
Anca Alexan ◽  
Oniga Ștefan ◽  
Alin Tisan
Keyword(s):  
Form Factor ◽  
Sensor Networks ◽  
Sensor Network ◽  
Low Cost ◽  
Factor Price ◽  
Raspberry Pi ◽  
Small Form ◽  
Processing Power ◽  
Cloud Database ◽  
Small Form Factor

Abstract Nowadays SoC’s miniaturization provide smaller yet more powerful devices that are perfect to be used as local hubs for small to medium sensor networks. Although sensors can now be easily connected directly to the cloud, a hub can simplify the process of bringing sensor to the IoT cloud. One of the most popular SoC board, Raspberry PI, is perfect for the hub role due to its small form factor, price, processing power and connectivity. Our proposed system consists in a SoC based low cost raspberry pi hub that connects two Bluetooth sensortag CC2650 modules to a mongoDB cloud database.

scholarly journals DOS Attacks on TCP/IP Layers in WSN

2013 ◽  
Vol 1 (2013) ◽  
pp. 40-45
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Networks ◽  
Sensor Network ◽  
Low Cost ◽  
Denial Of Service ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Renewable Energy Resources ◽  
Dos Attack ◽  
Dos Attacks

The emergence of sensor networks as one of the dominant technology trends in the coming decades has posed numerous unique challenges on their security to researchers. These networks are likely to be composed of thousands of tiny sensor nodes, which are low-cost devices equipped with limited memory, processing, radio, and in many cases, without access to renewable energy resources. While the set of challenges in sensor networks are diverse, we focus on security of Wireless Sensor Network in this paper. First, we propose some of the security goal for Wireless Sensor Network. To perform any task in WSN, the goal is to ensure the best possible utilization of sensor resources so that the network could be kept functional as long as possible. In contrast to this crucial objective of sensor network management, a Denial of Service (DoS) attack targets to degrade the efficient use of network resources and disrupts the essential services in the network. DoS attack could be considered as one of th

scholarly journals Laboratory Evaluations of Correction Equations with Multiple Choices for Seed Low-Cost Particle Sensing Devices in Sensor Networks

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3661 ◽  
Author(s):  
Wen-Cheng Vincent Wang ◽  
Shih-Chun Candice Lung ◽  
Chun Hu Liu ◽  
Chen-Kai Shui
Keyword(s):  
Sensor Networks ◽  
Low Cost ◽  
Before And After ◽  
Sensor Signals ◽  
Research Grade ◽  
Areas Of Interest ◽  
Equivalent Method ◽  
Correction Equations ◽  
Practical Recommendations

To tackle the challenge of the data accuracy issues of low-cost sensors (LCSs), the objective of this work was to obtain robust correction equations to convert LCS signals into data comparable to that of research-grade instruments using side-by-side comparisons. Limited sets of seed LCS devices, after laboratory evaluations, can be installed strategically in areas of interest without official monitoring stations to enable reading adjustments of other uncalibrated LCS devices to enhance the data quality of sensor networks. The robustness of these equations for LCS devices (AS-LUNG with PMS3003 sensor) under a hood and a chamber with two different burnt materials and before and after 1.5 years of field campaigns were evaluated. Correction equations with incense or mosquito coils burning inside a chamber with segmented regressions had a high R2 of 0.999, less than 6.0% variability in the slopes, and a mean RMSE of 1.18 µg/m3 for 0.1–200 µg/m3 of PM2.5, with a slightly higher RMSE for 0.1–400 µg/m3 compared to EDM-180. Similar results were obtained for PM1, with an upper limit of 200 µg/m3. Sensor signals drifted 19–24% after 1.5 years in the field. Practical recommendations are given to obtain equations for Federal-Equivalent-Method-comparable measurements considering variability and cost.

Growth of GaN on Lithium Gallate Substrates for Development of a GaN Thin Compliant Substrate

1997 ◽  
Vol 482 ◽  
Author(s):  
W. A. Doolittle ◽  
T. Kropewnicki ◽  
C. Carter-Coman ◽  
S. Stock ◽  
P. Kohl ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Cost ◽  
Alloy System ◽  
Attractive Alternative ◽  
Compliant Substrate ◽  
Out Of Plane ◽  
Magnitude Improvement ◽  
Microscopic Surface

AbstractThe GaN on LGO system is the near perfect template (due to extremely high etch selectivity) for developing a viable thin film/compliant GaN substrate. Herein, we report on our efforts to grow GaN on LGO, including improvement of the microscopic surface morphology using pre-growthpretreatments. We also report on the first transferred thin film GaN substrate grown on LGO, transferred off of LGO, and mounted on GaAs. With this approach, (InAl)GaN alloys can be grown on thin GaN films, implementing a truly “compliant” substrate for the nitride alloy system. In addition, the flexibility of bonding to low cost Si, metal or standard ceramic IC packages is an attractive alternative to SiC and HVPE GaN substrates for optimizing cost verses thermal conductivity concerns. We have demonstratedhigh quality growth of GaN on LGO. X-Ray rocking curves of 145 arc-seconds are obtained with only a 0.28 μm thick film. We present data on the out of plane crystalline quality of GaN/LGO material. Likewise, we show 2 orders of magnitude improvement in residual doping concentration and factors of 4 improvement in electron mobility as compared to the only previously reported electrical data. We show substantial vendor to vendor and intra-vendor LGO material quality variations. We have also quantified the desorption of Ga and Li from the surface of LGO at typical growth temperatures using in situ desorption mass spectroscopy and XPS.

scholarly journals Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H<sub>2</sub>O and FLASH-B in the tropical UTLS

2015 ◽  
Vol 8 (12) ◽  
pp. 13693-13727
Author(s):  
M. Ghysels ◽  
E. D. Riviere ◽  
S. Khaykin ◽  
C. Stoeffler ◽  
N. Amarouche ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Cost ◽  
Deep Convection ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
In Situ Techniques ◽  
Scientific Project ◽  
Water Vapor Mixing Ratio ◽  
The Impact

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, Sao Paulo St., Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within a small volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for measured stratospheric water mixing ratio is among the best ever reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B datasets are mutually consistent.

scholarly journals The Impact of Heterogenous Ultra-dense Network Technologies on the Performance of 4G and 5GNetworks

2020 ◽  
Vol 10 (1) ◽  
pp. 35-44
Keyword(s):  
Cost Effective ◽  
Cellular System ◽  
Small Cells ◽  
High Expectations ◽  
Dense Networks ◽  
High Data ◽  
Data Rates ◽  
Network Technologies ◽  
The Impact

The flood of applications that demand massive data has imposed a challenge for 5G cellular network in order to deliver high data rates, a better quality of service, and low energy consumption. Heterogenous ultra- dense networks are one of the major technologies to address such challenges. HUDNs play a big role in a cellular system. They deliver cost-effective coverage with low transmit power and high capacty to face the risen data and the high expectations of the user's performance. In this paper, we introduce the impact of small cells on the cellular system and the technologies the small cells utilize to make the cellular system faces the subscriber's demands. First, we discuss the fundamentals of used technologies in small cells. Next, we studied the small cell management. Then, self-organizing networks are studied. After that, we have reviewed the small cell's power consumption, mobility, and handover. Finally, the real-world experience of mm-waves and MIMO in 5G small cells

scholarly journals Power-Rate-Distortion Analysis Of Wireless Visual Sensor Network

2021 ◽  
Author(s):  
William Shaw
Keyword(s):  
Sensor Networks ◽  
Sensor Network ◽  
Low Cost ◽  
Sensory Information ◽  
Rate Distortion ◽  
Future Research ◽  
Wireless Multimedia ◽  
Visual Sensor ◽  
Visual Sensor Network ◽  
Clustering Model

The emergence of low-cost and mature technologies in wireless communication, visual sensor devices, and digtial signal processing, facilitates the potential of wirelss sensor networks (WSN). Like sensor networks which respond to sensory information such as temerpature and humidity, WSN interconnects autonomous devices for capturing and processing video and audio sensory information. This thesis highlights the following topics: (1) a summary of applications and challenges of WVSN; (2) the performance analysis of a wireless sensor network and wireless multimedia sensor network. To extend the system performance, two methods are provided in this thesis. First, mobile sink with node scheduling in multiple tracking targets is proposed. Second, a layered clustering model in sparing communication energy consumption in wirelsess visual sensor network is proposed. The experimental results validate our correlated approaches extend the system lifetime; (3) direction for Future Research are given.

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