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Choosing the first broadcaster to be the parent node as proposed by the leader-based routing (LBR) enables its Polling packet to be received earliest in a heterogeneous mobile sensor network (MSN) with short and intermittent availability of the mobile sink but may lead to an unreachable parent node. Furthermore, employing the three-way-handshaking as proposed by the link quality indicator (LQI)-based beaconless routing (LQI-BLR) may lead to a longer packet delivery delay. To avoid the aforementioned drawbacks simultaneously, the transmission power of the candidate parent node is included in the Polling packet in our proposed protocol. Along with the LQI, a mobile sensor can estimate its distance to the candidate parent node and its packet-receive ratio (PRR). If the PRR is higher than a preset threshold, the candidate can be chosen accordingly. Via simulations, we demonstrate that our proposed protocol can outperform LBR and LQI-BLR in a heterogeneous environment. In terms of the packet delivery ratio, our proposed protocol is able to achieve at least 35% and 20% of improvement when compared to LBR and LQI-BLR, respectively. Regarding the energy consumption and packet delivery delay, more than 20% improvement can be observed. [ABSTRACT FROM AUTHOR]

The internal mechanical motions of a dynamic system can serve as the basis for developing “free” sensors that probe operating state and potentially diagnostic health. Specifically, the interaction of a moving mechanical structure with an applied, nonintrusive field, e.g., an electric or magnetic field, can produce a signal that creates a sensor with little additional hardware. In this paper, bellows-and-diaphragm natural gas (BDNG) meters provide an illustrative example for three different approaches for transforming a metering mechanism and its consumption totalizer into a high quality flow meter. Detailed flow information provides a data-stream for nonintrusively monitoring the real-time operation of loads – in this example case, loads that consume natural gas such as burners, heaters, and engines. The flow information can also be used for fault detection and diagnostics, e.g., for finding leaks or correlating faulted operation with respect to the operation of electrical actuators or other flows of consumables like water. This paper examines three BDNG meters and presents a methodology for inexpensively adding digital flow-rate measurement capabilities to each meter. The methods developed here can in principle be applied to any dynamic machine for consumption estimation or fault detection. They can also be used with other nonintrusive field stimuli including light and sound. Mechanical retrofit techniques are described, and exemplary signal processing and estimation chains including compensation, flow rate estimation, and post processing are presented. [ABSTRACT FROM AUTHOR]

The use of three-dimensional registration techniques is an important component for sensor-based localization and mapping. Several approaches have been proposed to align three-dimensional data, obtaining meaningful results in structured scenarios. However, the increased use of high-frame-rate 3D sensors has lead to more challenging application scenarios where the performance of registration techniques may degrade significantly. In order to improve the accuracy of the procedure, different works have considered a representative subset of points while preserving application-dependent features for registration. In this work, we tackle such a problem, considering the use of a general feature-extraction operator in the spectral domain as a prior step to the registration. The proposed spectral strategies use three wavelet transforms that are evaluated along with four well-known registration techniques. The methodology was experimentally validated in a dense orchard environment. The results show that the probability of failure in registration can be reduced up to 12.04% for the evaluated approaches, leading to a significant increase in the localization accuracy. Those results validate the effectiveness and efficiency of the spectral-assisted registration algorithms in an agricultural setting and motivate their usage for a wider range of applications. [ABSTRACT FROM AUTHOR]

This work indicates two novel ocean current observation methods that based on a glider type mobile platform. Glider with current meters are ideal current observation solutions for marine scientists since they have merits of large dynamic area and low power consumption, but their measurement accuracy is insufficient now. The proposed 1st solution, single point current meter compensated inversion method (SPCMCIM), is a revolution of the conventional inverse method by solving the acoustic Doppler to current profiler (AD2CP) induced turbulence problem. It’s a cooperated AD2CP and single point current meter (SPCM) algorithm that compensates the contaminated first AD2CP layer data. The physical position of the SPCM is also optimized according to a finite element analysis (FEA) study to minimize the interference generated by the SPCM. The 2nd method is solving the area restriction problems that AD2CP can just apply to non-pure water environment namely single point and inertial measurement inversion method (SPIMIM). It utilizes the SPCM as the only current observation source and takes advantages of physical properties of ocean currents. The currents are constitute of stable layers and each of them has a stable velocity, so the glider’s velocity variation can be obtained by reading the SPCM. The velocity variation in the transition process between layers can be acquired by the low cost inertial sensors. Finally, these theoretical studies were verified in an onsite sea trial. The SPCM and AD2CP was mounted to an underwater glider to measure the currents and a ship equipped AD2CP was used to provide the arbitrary data. Both of the proposed method can effectively measure the current velocity and induced significant enhancement than the classical inversion method. In particular, the first method conducted improvement of 70% accuracy by average. The 2nd one also shows an obvious improvement and has the advantage to deploy to high purity water area like deep lakes or north pole. [ABSTRACT FROM AUTHOR]

A multi-camera dome consists of number of cameras arranged in layers to monitor a hemisphere around its center. In volumetric surveillance, a 3D space is required to be monitored which can be achieved by implementing number of multi-camera domes. A monitoring height is considered as a constraint to ensure full coverage of the space below it. Accordingly, the multi-camera dome can be redesigned into a cylinder such that each of its multiple layers has different coverage radius. Minimum monitoring constraints should be met at all layers. This work is presenting a cost optimized design for the multi-camera dome that maximizes its coverage. The cost per node and number of square meters per dollar of multiple configurations are calculated using a search space of cameras and considering a set of monitoring and coverage constraints. The proposed design is cost optimized per node and provides more coverage as compared to the hemispherical multi-camera dome. [ABSTRACT FROM AUTHOR]

Positive displacement water meters are found throughout the world’s water distribution networks to totalize water consumption. Containing internal permanent magnets, the water meters are underutilized sensors. Flow data from these meter locations can be used to non-intrusively identify the operation of individual water loads from an aggregate data stream at the meter. This article models these meters as nonideal magnetic encoders and presents a methodology for inexpensively retrofitting these meters with digital flow rate measurement capabilities, effectively bringing them into the growing body of smart metering devices and non-intrusive load monitoring without any contact with the water passing through them. We present a model of the magnetic field produced by these meters, discuss associated magnetic sensing hardware, and describe compensation, flow rate estimation, and post-processing algorithms for flow rate extraction. Verification is provided with experimental results. [ABSTRACT FROM AUTHOR]

A Doppler velocity log (DVL) provides a three-dimensional representation of the velocity of an underwater vehicle to the vehicle’s DVL-aided inertial navigation system (INS). It is a key element in determining the precision of the INS. This paper presents an algorithm for reducing the error in the DVL as a way of improving the navigation of an autonomous underwater vehicle (AUV). We also investigate and analyze the effect that the seafloor’s deviations have on DVL measurement error. Finally, the performance of the proposed algorithm is examined through both AUV simulation and experimentally. The results show that the proposed technique can indeed effectively correct DVL errors. [ABSTRACT FROM AUTHOR]

Underwater sensor networks (UWSNs) play a significant role in ocean exploration and monitoring by gathering information and routing it to the ground stations. Therefore, the design of efficient routing protocols is necessary as it guarantees robust and reliable data delivery from the source nodes to the destination nodes. However, the effects of underwater environment, dynamic nature of the channel for acoustic, radio and optical waves, and harsh underwater noise conditions, make the routing protocol design a challenging task. This article overviews various issues which are faced in designing the routing protocols and summarizes the popular routing protocols for UWSNs alongside their pros and cons. More specifically, the routing protocols are characterized into three main categories; localization-based, localization-free and cooperative schemes. The performance of these protocols are discussed with respect to various network parameters such as energy consumption, network lifetime, delay, reliability, and communication overheads. Towards the end, new directions for potential research in improving routing protocols performance in UWSNs are highlighted. [ABSTRACT FROM AUTHOR]

With the development of Internet of Things (IoT) technology, people’s demand for indoor location-based services is growing. Indoor magnetic field has a wealth of fingerprint information that can be combined with position stamps to construct an indoor magnetic map (IMM). Localization scenarios based on IMM include personnel attendance, equipment tracking, and fire emergency, etc. However, the localization technology is complicated, the localization accuracy based on IMM is generally low, and the localization result lacks credibility due to the fluctuation of indoor magnetic field. Therefore, it is urgent to study a novel localization method in terms of the tradeoff among complexity, accuracy and credibility, which is the purpose of this article. First, the Euclidean distance constraint (EDC) with a variable search radius is proposed to make a rough estimate of the entity’s location. Then the iterative interpolation method (IIM) is proposed to refine the local-IMM, and the multi-magnetic- fingerprint-fusion (MMFF) is proposed to match the magnetic fingerprint based on the refined local-IMM. In short, the proposed method is called focusing matching localization method by combining coarse estimation with fine estimation, which can be abbreviated as EDC-IIM-MMFF. Finally, the effectiveness of the proposed localization method is verified by a series of experiments. The tests show that the root mean square error (RMSE) of location solved by the proposed method is less than 0.3 meters, and the 99% cumulative distribution function (CDF) of location error is less than 0.5 meters, and the complexity is lower than the existing methods, such as Gaussian process regression (GPR), extended Kalman filter (EKF), particle filter (PF), etc. [ABSTRACT FROM AUTHOR]

One of the reasons which impede applications of ultrasonic beam deflection flowmeters is their calibration that usually needs to be performed across the whole range of measured flow rates. In this paper we have aimed to show that given the directivity pattern of ultrasonic transducers, one can design a beam deflection flowmeter with just one transmitting and one receiving transducer and reduce the calibration process of such a device to a single measurement. Moreover, we show how to optimize parameters of the transmitter-receiver setup in order to maximize flow measurement accuracy. It leads us to simple and approximate formulas that relate the size and tilt angles of the transducers to measurement range so that the worst-case measurement error is minimized. [ABSTRACT FROM AUTHOR]

This paper presents a two-electrode type conductivity sensor, using copper as electrodes, coated with a polyimide layer called DQN-60. This sensor is specially designed to be robust yet inexpensive for applications like precision farming and fishery. A new conductivity sensing principle is proposed which is based on impedimetric measurement (both magnitude and phase) at a frequency of 200 kHz. This sensing principle is developed by analyzing the electrical equivalent model of the proposed sensor and is aimed at eliminating the effect of the interface impedance and the cell capacitance thus making the measurement linear and accurate. A prototype meter is developed with 3.75% maximum full-scale error in the range of 0.5 $\mu \text{S}$ /cm to 20 mS/cm. The temperature compensation, calibration, and detailed experimental results are also discussed. [ABSTRACT FROM AUTHOR]

The pH is an important parameter to control in many industrial processes carried out at high pressures. However, the measurement of pH in pressurized systems is challenging due to the difficulty in the development of pH sensors resistant to these conditions. This work presents a low-cost technique using image analysis and the hsv (hue, saturation, and value) color system to measure the pH in atmospheric and pressurized systems. First, a calibration curve was prepared with buffer solutions in a pH range from 2 to 10 using a mixture of pH indicators whose color varies at each pH unit. The hsv color system was determined at pressures up to 6.0 MPa and correlated to the pH of each buffer solution. Second, to evaluate the reliability of the relation between pH and hue, an acid–base titration curve with HCl and NaOH was performed. During the titration, the pH was monitored with a pH meter and the results were in good agreement with those obtained from the pH–hue correlation. Finally, to corroborate the applicability of the method in a pressurized system, the CO2–H2O system was studied, determining the pH of pure water pressurized between 0.1 and 5.0 MPa with CO2 at 298 K. The results were similar to theoretical pH values calculated from the solubility of CO2 in water at the experimental conditions. Hence, we have provided a new low-cost method using real-time image analysis and the hsv color system to quantify pH values in atmospheric and pressurized systems, in which the detection sensing achieves accurate measurements [ABSTRACT FROM AUTHOR]

Early kick and loss detection is a major concern in any drilling operation. A real-time return flow rate measurement would be an added advantage for the early kick and loss detection for conventional drilling systems. In this paper, the real-time estimation of the return flow rate during drilling is studied, using a Venturi channel. A reduced order, 1D, mathematical equation for the shallow water flow/open flow in the Venturi channel is investigated with various non-Newtonian friction models. The volumetric fluid flow rate is estimated online using an unscented Kalman filter. In order to improve the fluid flow rate estimation, the model is adapted to some of the rheological parameters in real time. A simple and effective fit–for–purpose friction model is developed and compared with the other friction models from literature. The fit–for–purpose model has the least estimation error (RMSE 1.465%) and requires less information as inputs. The proposed method exhibits promising potential to be used as an online return flow rate measurement for early kick and loss detection in conventional drilling. [ABSTRACT FROM AUTHOR]

A multi-band body-worn distributed exposure meter (BWDM) is designed and calibrated for diffuse fields in a reverberation chamber (RC) for personal exposure assessment in indoor environments. The BWDM uses 22 nodes distributed over the torso and measures the incident power density ($S_{\mathrm{ inc}}$) on body for 11 telecommunication bands in the frequency range of 790–5513 MHz. In order to calibrate the measurement device in diffuse fields, a protocol is proposed for on-body calibration of the BWDM. This protocol is applicable to wearable personal exposure meters in general. The BWDM and the proposed calibration protocol are validated in five indoor locations and five frequency bands (the downlink bands at 800, 900, 1800, and 2100 MHz as well as Wi-Fi 2 GHz) using a tri-axial broadband antenna and a spectrum analyzer (SA). The calibration shows that the BWDM has a relatively low measurement uncertainty with a 68% confidence interval on its antenna apertures, in the range 3.4–5.5 dB. A maximum difference of 0.9 dB is obtained for the total exposure in the test areas between the measurements of the BWDM and SA, which is an excellent agreement. [ABSTRACT FROM AUTHOR]

Business models around energy performance of lighting systems and managed services make increasing use of the energy metering sensor data. However, accurate submetering solutions remain expensive and complex to commission. With the goal of realizing a low-cost metering sensor solution that provides reasonable measurement accuracy, we consider nonintrusive load monitoring for lighting systems using virtual energy submetering. We propose analytics methods using metered lighting energy sensor data to address three problems: 1) provide initial validation of assets of a lighting control system; 2) disaggregate energy consumption across distinct control groups of a validated system enabling usage and performance monitoring; and 3) monitor and manage lighting system asset over lifecycle. The proposed methods are evaluated using an experimental testbed in a commercial building. [ABSTRACT FROM PUBLISHER]

Smart Grid is being proposed as a prime solution for the effective growth of electricity market allowing the heterogeneous players to assume real-time autonomous reactions to the changing conditions of the grid and new services (such as demand response, DR, and vehicle-to-grid, V2G) to be introduced. One of the main requisite for such development is represented by advanced metering infrastructure (AMI) which typically provides timely and reliable information about the smart grid. This paper introduces an innovative first block of the AMI represented by a smart sensor based on ARM architecture. The prototype is described in terms of both the hardware and software features and the metrological characterization is provided through the experimental test according to OIML R-46. [ABSTRACT FROM PUBLISHER]

This paper aims to describe the role of advanced sensing systems in the electric grid of the future. In detail, the project, development, and experimental validation of a smart power meter are described in the following. The authors provide an outline of the potentialities of the sensing systems and IoT to monitor efficiently the energy flow among nodes of an electric network. The described power meter uses the metrics proposed in the IEEE Standard 1459–2010 to analyze and process voltage and current signals. Information concerning the power consumption and power quality could allow the power grid to route efficiently the energy by means of more suitable decision criteria. The new scenario has changed the way to exchange energy in the grid. Now, energy flow must be able to change its direction according to needs. Energy cannot be now routed by considering just only the criterion based on the simple shortening of transmission path. So, even energy coming from a far node should be preferred, if it has higher quality standards. In this view, the proposed smart power meter intends to support the smart power grid to monitor electricity among different nodes in an efficient and effective way. [ABSTRACT FROM PUBLISHER]

Advanced metering infrastructures (AMIs) are thought to deliver services to both citizens and utility companies in smart city context. All services are based on battery powered terminal devices (smart meters), which get to the internet through suitable gateways. Smart meters are usually featured with radio frequency short range antennas and must be within the coverage range of at least one gateway. The economic sustainability of the AMIs depends on the right compromise between the number of necessary gateways and the lifetime of terminal device battery. In this paper a novel method based on statistical treatment of the received signal strength indication value is proposed to address the problem of the remote management of the smart meter transmission power. On the basis of an estimate of signal quality, it allows the transmission power to be regulated with the aim of assuring both low transmission error rates and battery capacity saving. [ABSTRACT FROM PUBLISHER]

In underground low-pressure gas distribution pipelines, ground water enters the pipeline through cracks. This is known as the water ingress problem, and it occurs predominantly in the monsoon season, when the water table is high. This issue is currently detected based on complaints from the users. In order to arrive at an efficient and reliable processing technique, experimental results of pressure and flow on an existing low-pressure gas pipeline are reported in this paper. Several experiments for leak location, severity of the leak, water ingression with various volumes of water followed by removal of water are conducted. Healthy network loading data collected over a 24 h period is used to verify the robustness of the derived parameters for water ingression detection. The present technique can detect leaks easily with a leak valve opening of 30o. Robust detection of water ingression with more than 10% of pipe volume is possible. [ABSTRACT FROM PUBLISHER]

Appliance state sensing is a load monitoring method that requires the ON/OFF states and global consumption measurements of appliances in order to achieve energy disaggregation. Previously proposed sensor networks employed uncalibrated, overrated, and costly wireless modules to collect appliance states. In contrast, we present a simple communication scheme, in which data are transmitted through the powerline to a main meter. For this purpose, we designed a smart sensor, the circuitry of which operates as a load signature generator. It generates fixed-amplitude and short-duration rectangular current pulses that encode information about the status of an appliance. For evaluation, we tested four sensors in a small electrical model and performed a numerical simulation using raw current waveforms contained in the reference energy disaggregation data set. The performance of the applied signal processing algorithms shows a symbol error rate of less than 1% when pulse position modulation with amplitudes of 2 A or more is used. [ABSTRACT FROM PUBLISHER]

Unfortunately, in the above article , a minor mathematical error needs to be corrected. corresponds to the flow velocity in a Z-configuration meter, whereas the meter shown schematically in Fig. 1 is a V-configuration meter. The difference between the two equations is that the equation for the V-configuration meter has an extra factor of two in the denominator. This correction does not affect the remainder of the article, as the correct equation was used during data processing. [ABSTRACT FROM AUTHOR]