Distributed Region-Based Monitoring in Low-Power Listening Wireless Sensor Networks

Abstract

Advancement in IoT technology and the concept of Information-Centric Networking lead to less importance of node individuality since several nodes can work interchangeably. Multiple sensor nodes can be grouped into a region and monitored as one instance to guarantee sufficient coverage over the region. Therefore, a single node fault often does not need to be reported unless it is the last node in the region. In addition, there are occasions where a central monitor station cannot rely on continuous data delivery from nodes or regions to decide whether they are still alive, such as situations when nodes are deployed to detect rare events. Moreover, low-power listening MAC protocols, which significantly help reducing power consumption while nodes are mostly idle, put a lot more work on the transmission process. In such situations it is desirable to minimize status reports to the central monitor station. A distributed region-based monitoring scheme, or DRMON, is then proposed to facilitate this circumstance. This approach designates a representative to each region so that it can be used as an indicator of the region's status with a mechanism to re-elect a new representative until all nodes in the respective region are dead, implying region inactiveness. We evaluate the suitability of DRMON over various scenarios in two aspects: centralized vs. distributed monitoring schemes and individual-based vs. region-based monitoring schemes. Simulation results indicate that region-based schemes outperform the individual schemes in terms of power consumption and scalability when the number of regions is low. The distributed schemes also yield better efficiency in terms of message overhead and load distribution. In addition, detection accuracy of all schemes is not significantly different and fault detection delay is guaranteed. This outcome suggests that in the case where existence of individual node is out of concern, distributed region-based fault monitoring scheme could be employed to reduce energy usage and lower message overhead while retaining the detection accuracy.

Technical Efficiency of Private Clinics Under Universal Coverage Scheme in Bangkok, Thailand

“…It was implied that most of private clinics under UC can manage their own resources to provide healthcare service efficiently. The average pure technical efficiency score (TEVRS) was reach at 0.98, it was consistent with previous study of Pattamsiriwat that studied the efficacy and cost of the hospital office of the permanent secretary, Ministry of Public Health in the financial sector finance research program evaluating the impact of universal health care coverage on hospital finance (Pattamasiriwat, 2009), the result showed that average efficiency of center hospitals, general hospital and community hospitals were 0.94, 0.86, and 0.85, respectively. However, the result was different from the study in health sub-district offices in 2008, efficiency scores (DEA, VRS assumption) range from 0.60 to 0.75 and averaged to 0.69.…”

“…Pattamsiriwat studied the efficacy and cost of the hospital office of the permanent secretary, Ministry of Public Health in the financial sector finance research program evaluating the impact of universal health care coverage on hospital finance (Pattamasiriwat, 2009). The study was based on the annual hospital financial report, the input variables were the number of patients, the number of outpatients and average relative weight while input variables were salaries and wages, compensation, service costs, number of beds, and number of personnel.…”

“…In addition, there was study in health sub-district offices by Pattamsiriwat (Pattamasiriwat, 2008); the case study of cost efficiency among 246 health sub-district offices in 12 provinces, focus on health sub-district offices based on 246 units located in 12 provinces. The outputs consisted of 4 variables and the inputs consist of 3 variables inclusive of wages and salaries, compensation to officers, and operating expenses.…”