Wireless Sensor Networks (WSNs) are applicable in numerous domains, including industrial automation where WSNs may be used for monitoring and control of industrial plants and equipment. However, the requirements in the industrial systems differ from the general WSN requirements. In recent years, standards have been defined by several industrial alliances. These standards are specified as frameworks with modifiable parts that can be defined based on the particular application of WSN. However, limited work has been done on defining industry-specific protocols that could be used as a part of these standards. In this survey, we discuss representative protocols that meet some of the requirements of the industrial applications. Since the industrial applications domain in itself is a vast area, we divide them into classes with similar requirements. We discuss these industrial classes, set of common requirements and various state-of-the-art WSN standards proposed to satisfy these requirements. We then present a broader view towards the WSN solution by discussing important functions like medium access control, routing, and transport in detail to give some insight into specific requirements and the classification of protocols based on certain factors. We list and discuss representative protocols for each of these functions that address requirements defined in the industrial classes. Security function is discussed in brief, mainly in relation to industrial standards. Finally, we identify unsolved challenges that are encountered during design of protocols and standards. In addition some new challenges are introduced and discussed.

An Industrial Perspective on Wireless Sensor Networks — A Survey of Requirements, Protocols, and Challenges

Smartphone-based construction workers' activity recognition and classification

In last two decades, various monitoring systems have been designed and deployed in urban environments, toward the realization of the so called smart cities. Such systems are based on both dedicated sensor nodes, and ubiquitous but not dedicated devices such as smart phones and vehicles’ sensors. When we design sensor network monitoring systems for smart cities, we have two essential problems: node deployment and sensing management. These design problems are challenging, due to large urban areas to monitor, constrained locations for deployments, and heterogeneous type of sensing devices. There is a vast body of literature from different disciplines that have addressed these challenges. However, we do not have yet a comprehensive understanding and sound design guidelines. This paper addresses such a research gap and provides an overview of the theoretical problems we face, and what possible approaches we may use to solve these problems. Specifically, this paper focuses on the problems on both the deployment of the devices (which is the system design/configuration part) and the sensing management of the devices (which is the system running part). We also discuss how to choose the existing algorithms in different type of monitoring applications in smart cities, such as structural health monitoring, water pipeline networks, traffic monitoring. We finally discuss future research opportunities and open challenges for smart city monitoring.

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The Sensable City: A Survey on the Deployment and Management for Smart City Monitoring

Nowadays, computer systems are presented in almost all types of human activity and they support any kind of industry as well Most of these systems are distributed where the communication between nodes is based on computer networks of any kind Connectivity between system components is the key issue when designing distributed systems, especially systems of industrial informatics The industrial area requires a wide range of computer communication means, particularly time-constrained and safety-enhancing ones From fieldbus and industrial Ethernet technologies through wireless and internet-working solutions to standardization issues, there are many aspects of computer networks uses and many interesting research domains Lots of them are quite sophisticated or even unique The main goal of this paper is to present the survey of the latest trends in the communication domain of industrial distributed systems and to emphasize important questions as dependability, and standardization Finally, the general assessment and estimation of the future development is provided The presentation is based on the abstract description of dataflow within a system

Computer Communication Within Industrial Distributed Environment—a Survey

Synchrophasor estimation accuracy is a well-known critical issue in systems for smart grid monitoring and control. This paper deals with an in-depth analysis of the effect of both steady-state and dynamic disturbances on single-cycle and multicycle windowed discrete Fourier transform (DFT)-based synchrophasor estimators. Unlike other qualitative or simulation-based results found in the literature, this work provides two accurate and easy-to-use analytical expressions that can be used to determine the worst case range of variation of the total vector error (TVE) due to off-nominal frequency deviations. In such conditions, estimation accuracy is limited by two factors, i.e., the infiltration caused by the input signal image frequency and the scalloping loss associated with the spectrum main lobe of the chosen window. Starting from the aforementioned general analysis, a new two-term window minimizing the detrimental effects of image frequency tone is proposed. The accuracy of the related DFT-based synchrophasor estimator is evaluated under both static and dynamic conditions, which is the most interesting scenario for future smart grids. Moreover, the effect of waveform frequency measurement uncertainty on scalloping loss compensation is quantified. Several simulation results (including the effects of noise, harmonic distortion, and amplitude and phase modulation) confirm that the proposed window can significantly improve the accuracy achievable with a simple single-cycle DFT estimator. Indeed, TVE values much smaller than 1% can be achieved even in the worst case conditions reported in the standard IEEE C37.118.1-2011, when the frequency waveform deviations are within ±4% of the nominal value. In addition, the proposed solution could be useful to improve the performance of more complex dynamic phasor estimators, e.g., those in which the first- and second-order terms of the phasor Taylor series expansion result from the differences of consecutive DFT-based phasor estimates.

Accuracy Analysis and Enhancement of DFT-Based Synchrophasor Estimators in Off-Nominal Conditions

The International Electrotechnical Commission (IEC) 61850 standard describes the communication inside the substation automation system (SAS) setting the base for new interoperating devices that share information using the Ethernet network infrastructure. More recently, the request of time synchronization among SAS components for the timestamping of critical events or synchrophasor measurement has generated a very high interest in the IEC 61850 working group for distributed synchronization protocols like IEEE 1588. This paper analyzes the current situation, matching different implementations of the IEEE 1588, and their respective accuracy, with the requirements of typical SAS applications: from the millisecond synchronization accuracy required by fault recorder application to the microsecond required by the sampled values (SV). The main focus of this paper is on the integration of IEEE 1588 with real already existing systems, and the goal is the performance comparison of different architectures. For these reasons, experimental tests have been carried out using a real SAS network infrastructure [redundant gigabit optical fiber Ethernet network managed using rapid spanning tree protocol (RSTP)]. The results show that, under ideal conditions, the IEEE 1588 protocol can achieve synchronization accuracy slightly worse (80 ns) than legacy IRIG-B systems (15 ns). However, IEEE 1588 makes possible a great cabling reduction and a simplified maintenance when synchronization is directly transferred on the SAS system bus. On the other hand, experiments highlight that nodes connected through a legacy RSTP infrastructure, which does not support IEEE 1588 messages, can lose the time synchronization in the case of network traffic or reconfiguration of the network. Therefore, the integration of IEEE 1588 over existing IEC 61850 station bus is basically a tradeoff between installation costs and performance since it requires the replacement of already installed Ethernet infrastructure. In the last part, this paper analyses the challenges for the next SAS generation that has to combine on the same plants the high accuracy IEEE 1588 implementation with high-availability protocols based on IEC 62439. Since the lifetime of an SAS is more than ten years and the adoption of these technologies takes several years, some solutions that introduce synchronization and high-availability protocols guaranteeing compatibility with existing technologies have been analyzed, too. For instance, an adaptation block that (when attached to a high-availability network) reconstructs the interface signals (e.g., synchronization signals) required by traditional bay has been proposed.

On the Use of IEEE 1588 in Existing IEC 61850-Based SASs: Current Behavior and Future Challenges

In this paper, the WirelessHART communication scheme is investigated. The protocol is at first described, in order to underline the key aspects of its design; then, a simulation tool is presented: it enables analysis that accounts for both protocol and physical layers issues. In particular, interference effects on protocol choices can be easily analyzed. The experimental results, obtained from simulations, highlight improvements of WirelessHART with respect to IEEE 802.15.4 standard, concerning the Packet Error Ratio (PER) degradation of interfering networks.

Investigating WirelessHART coexistence issues through a specifically designed simulator

The growing interest towards green and efficient use of electrical energy has recently pushed the industry of street light control systems. In the past, very simple on/off switching mechanism based on daylight sensing and cyclic preventive maintenance procedures were adopted. Nowadays, intelligent control systems offering remote supervision have strongly contributed to a change in perspective in maintenance engineering form a traditional “Fail and Fix” view to a “Predict and Prevent” approach. However, most of the infrastructure is already in place and replace street light with improved units has to be economical feasible. Traditional solutions exploit Power Line Communications (PLCs). In this paper we propose a wireless retrofitting of lamps, which has some advantages due to the independence from power line faults. In addition, the service provider usually ignores the exact location of the lamp poles and the integration with Geographic Information System (GIS) databases requires a preliminary on-site survey. The novelty of our proposal relies on the exploitation of nodes self location capability. Radios based on Chirp Spread Spectrum (CSS) modulation are used in order to achieve a good spatial resolution without the adoption of expensive GPS modules. In particular, experimental results are focused on the ranging capabilities of such devices, showing the feasibility of the proposed approach. Open field trials, mimicking real world applications, have shown an overall accuracy on the order of one meter.

On the development of a wireless self localizing streetlight monitoring system

Nowadays, the wide diffusion of smartphones has completely changed the interaction of people with the surroundings In fact these devices are equipped with a large number of sensors, like GPS receiver, 3-axis accelerator, which can enrich the user experience, collecting data from the external environment Moreover, additional sensors can be used to enlarge the set of data providing information usually not available in a smartphone, like biomedical data Usually, Bluetooth is used to connect external sensors to smartphone Several commercial solutions are already available on the market Unfortunately, different types of smartphone require the use of dedicated external sensors, due to the different Bluetooth data profile supported by the different Operative System (iOS, Android) In this paper the Bluetooth Hands-Free profile has been evaluated to transmit sensor information to smartphone, since it is the only profile supported both by Android as well as iOS devices A prototype of a photoplethysmographic sensor with Hands-Free interface has been realized and interfaced to commercial smartphone, showing the feasibility of this approach

Evaluation of Bluetooth Hands-Free profile for sensors applications in smartphone platforms

Managing a large building construction site is a really complex task. Nowadays, many controllers have to daily check the site collecting information in order to inform managers about the construction progress. Recently, several software applications, compatible and integrated in most of commercial CAD tools, have been developed to help managers in collecting information. These tools furnish the managers on-site access to technical documentation, but are standalone tool very poorly connected with the site infrastructure. For this reason, some proposals have been suggested in literature to enable real-time data collection about site status exploiting communication facilities (e.g. wireless sensor networks). The work discussed in this paper extends this approach including localization-aware and task-aware mobile computing based on the use of smartphones and tablets. These devices natively offer intuitive and user-friendly interfaces, dramatically reducing time in personnel training. In particular, ranging and localization techniques on most diffused smart platforms have been successfully tested, also by means of external hardware plugins.

C. M. De Dominicis

Papers

On the Use of IEEE 1588 in Existing IEC 61850-Based SASs: Current Behavior and Future Challenges

Investigating WirelessHART coexistence issues through a specifically designed simulator

On the development of a wireless self localizing streetlight monitoring system

Evaluation of Bluetooth Hands-Free profile for sensors applications in smartphone platforms

Smartphone based localization solution for construction site management