(searched for: Real-time Magnetic Observatory Network: A Review)
Published: 13 September 2021
European Journal of Environment and Earth Sciences, Volume 2, pp 1-2; https://doi.org/10.24018/ejgeo.2021.2.5.177
The International Real-time Magnetic Observatory Network (INTERMAGNET) was based on the Observatory Instruments in Ottawa, Canada in August 1986. After coordination between the United States and British Geological Surveys, this network could use to record Earth’s magnetic field e.g., Disturbance storm time (Dst) index that monitored a large geomagnetic storm. The INTERMAGNET has been used in to access the observed communicating. The production of geomagnetic products could be obtained in real-time. Overseeing the operations of INTERMAGNET, the first geomagnetic Information Node (GIN) was established in 1991, the first CD-ROM/DVD was published in 1991.
Journal of Sensors, Volume 2016, pp 1-8; https://doi.org/10.1155/2016/7048141
Road traffic accidents are one of the main causes of death and disability worldwide. Workers responsible for maintaining and repairing roadways are especially prone to suffer these events, given their exceptional exposure to traffic. Since these actuations usually coexist with regular traffic, an errant driver can easily intrude the work area and provoke a collision. Some authors have proposed mechanisms aimed at detecting breaches in the work zone perimeter and alerting workers, which are collectively called intrusion alarm systems. However, they have several limitations and have not yet fulfilled the necessities of these scenarios. In this paper, we propose a new intrusion alarm system based on a Wireless Sensor Network (WSN). Our system is comprised of two main elements: vehicle detectors that form a virtual barrier and detect perimeter breaches by means of an ultrasonic beam and individual warning devices that transmit alerts to the workers. All these elements have a wireless communication interface and form a network that covers the whole work area. This network is in charge of transmitting and routing the alarms and coordinates the behavior of the system. We have tested our solution under real conditions with satisfactory results.1. IntroductionEach year, road accidents are the cause of an unacceptable number of fatalities and injuries everywhere in the world. As a result, road safety is one of the main concerns for citizens and governments nowadays and a lot of effort has been put into reducing these figures. For instance, road accidents and fatalities in the EU in 2015 have fallen by 22% and 46%, respectively, since 2004, according to data published by the European Road Safety Observatory. Despite these encouraging results, there is still a lot of work ahead.One of the main action points in reducing traffic accidents is improving the conditions of roads and other infrastructures. These actions usually encompass the deployment of construction sites on roads and highways. In many cases, the complete shutdown of the roadway is not possible and these work zones have to share the road surface with regular traffic, with little or no protection between them. This results in an evident hazardous environment for both workers and road users. A survey released by the UK Highways Agency in 2006 stated that up to 20% of road workers had suffered some injury caused by passing vehicles in the course of their careers and 54% had experienced a near miss with a vehicle.In order to increase the visibility and safety of workers, construction sites are typically marked by signs, cones, and other channelizing devices, as seen in Figure 1. Their goal is to warn and guide road users creating a barrier around the perimeter of the work zone. A very important characteristic of these barriers is that they have to be composed of crashworthy devices, such as cones and barrels, in order to cause minimal damage if hit by a vehicle. However, this implies that distracted or errant drivers can easily intrude into the work area.Figure 1: Example of a work zone delimited by barrels.Over the years, several systems and methods have been proposed to address this problem, with the particular goal of alerting workers about the immediate danger. They are generally called intrusion alarm systems.The work in  is the most recent survey on traffic safety devices, carried out by the Kansas Department of Transportation in 2011. In this work, intrusion alarm systems are described as any sensing technology mounted on work zone barriers that triggers an alarm in the event of an invasion by an errant driver. Their main constraint is that the alarm has to warn workers effectively and with enough reaction time to avoid the incoming danger. The majority of systems are based on microwave and infrared beams, while others utilize pneumatic tubes placed on the ground. The study concludes that there are evident problems with the existing systems, based on surveys to users. They have a high number of false alarms, their setup process is long and difficult, and, more importantly, the generated alarms are very difficult or impossible to hear over the usual noise of work zones.The work in  is another review of intrusion alarm systems published by the AHMCT Research Center in 2009. Apart from some of the systems already analyzed in , this paper reviews other types of devices. The first ones are systems that augment the traditional road cone with a tipping sensor that triggers an alarm when the cone is hit by a vehicle. The most prominent example of this kind of systems is the SonoBlaster, commercialized by Transpo Industries. These devices present the following problems: they can generate false positives if the cones are tipped by the wind or any other not threatening agent; it could be possible for a vehicle to invade the work area without tipping a cone; and the durability of the device could be compromised by the impacts.They also review systems in which a transmitter unit and a receiver unit are aligned to create an invisible continuous barrier along the perimeter of the work zone based on a pulsed microwave beam . The main disadvantage of this system is the complexity of its deployment and maintenance, since the alignment between the transmitter and the receiver has to be preserved at all times. Both these devices have another shared drawback, present in most of the analyzed intrusion systems: the alarm that the systems generate is very difficult to hear in a construction environment.To address this problem, a device called Wireless Warning Shield was proposed and patented in 2006 . It was based on a wireless communication system mounted on cones and also equipped with tipping sensors. Each individual worker would also wear an alert device, which would receive alarms from the system wirelessly in case of a breach. However, this product was never fully developed and never reached a functional stage.The authors in  conclude that, given the virtually inexistent commercialization of these kind of devices, current intrusion alarm systems have significant limitations both from their technical implementation as well as from worker acceptance.In a different line of research, several systems have been proposed within the field of traffic management and road safety that are based on Wireless Sensor Networks (WSNs) [5–7]. Over the last few years, WSNs have been applied to a huge variety of scenarios due to their low cost, high scalability, and ease of deployment. In this particular field, several works make use of WSNs to monitor, study, and evaluate traffic patterns using techniques based on infrared , ultrasonic , or magnetic sensing [10, 11]. In , the authors propose a WSN-based system especially aimed at monitoring traffic in or near short-term work zones. However, to the best of our knowledge, there are no existing systems that use WSNs in the context of intrusion detection. WSNs have the potential of enhancing these systems by providing a way of communication to work zone environments.In this paper, we propose an intrusion alarm system for road work zones based on a WSN. Our system is composed of two main elements: vehicle detectors to monitor the perimeter and warning devices to individually alert the workers. All these elements are connected forming a network that covers the whole work area. Its main features are as follows:(i)Individual alerts: workers are warned of the incoming danger by means of their individual warning device. This way we can ensure that workers are effectively alerted even if they are far from the source of the alarm or in a noisy environment, which was one of the most worrying problems of previous intrusion alarm systems. In addition, these devices can be used to monitor and control the working conditions, such as temperature and impacts. They are also light and comfortable to wear, guaranteeing worker acceptance.(ii)Wireless Sensor Network: the WSN provides a way of communication within the work zone. Not only could WSNs reliably transmit and present alarms, but they could also be used to communicate any other type of information relevant to the particular scenario. For instance, the crew manager can monitor the activity and location of workers by means of their individual warning devices.(iii)Robustness: vehicle detectors can detect invasions of the perimeter whether the cone is hit or not. This is an advantage over previous systems.(iv)Easy deployment and setup: our vehicle detectors do not have separate transmitter and receiver units. Thus, there is no need for a precise alignment when deploying the system. They are also lightweight and easy to mount. This expedites the deployment and setup phase in comparison to most previous systems.(v)Autonomy: all the elements are powered by rechargeable batteries, whose duration is completely adequate for regular work zone schedules.2. Materials and MethodsOur intrusion alarm system is especially aimed at improving safety in short-term work zones. On these works, it is common for the workers to share the road with the adjacent traffic with not enough safety measures that protect them from errant drivers. The most common entry point into the work zone is the first part of the perimeter, which is usually delimited by cones, so these are the places where the vehicle detectors are placed (see Figure 2). The workers will be alerted by a personal warning device that all of them carry during their work activities. The vehicle sensors and warning devices are connected by a wireless network to deliver the alerts and configure the system.Figure 2: Top view of the target scenario.In order to design our system, some key goals were defined to ensure the suitability to the target scenario:(i)The deployment should be easy, allowing workers to setup the system in a reasonable time.(ii)The system should be usable in the majority of the road scenarios, so there should not be special placem
The THEMIS Mission pp 413-451; https://doi.org/10.1007/978-0-387-89820-9_18
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Space Science Reviews, Volume 141, pp 413-451; https://doi.org/10.1007/s11214-008-9457-6
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