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A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation

View Article: PubMed Central - PubMed

ABSTRACT

Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment) and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs) are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.

No MeSH data available.


Energy consumption and the probability of  with excavated tunnel length.
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sensors-17-00435-f010: Energy consumption and the probability of with excavated tunnel length.

Mentions: Figure 10 shows the energy consumed by the sensor tagged on the truck as the length of the tunnel excavation increases. With the given analysis condition, the proposed mobility-aware adaptive duty cycling mechanism consumes less energy than that of the periodic, until the length of the excavated tunnel reaches at 1268 m, in which case the probability is 33.7%. This probability is computed by dividing the truck moving time by the total staying time in the tunnel and corresponds to the value obtained from Equation (6). For the tunnel length, the probability that the proposed mechanism consumes less energy than the periodic one can be computed as:(9)p= TMTM+TS≤(αD+1−D)(β−1)αβ−12·LTunnelvM2·LTunnelvM+TS≤(αD+1−D)(β−1)αβ−1LTunnel≤vM·TS·(αD+1−D)(β−1)2{αβ−1−(αD+1−D)(β−1)} where is the duration of the truck moving, is the stopped time and is the velocity of the moving truck. Note that the excavation face is getting farther away from the tunnel entrance as the tunnel excavation progressed, so the travel distance of the dump truck gets longer. Accordingly, for the proposed adaptive mechanism, the number of duty cycles that use increases with the excavated tunnel length. As a result, the energy consumption increases faster than for the periodic case, which uses .


A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation
Energy consumption and the probability of  with excavated tunnel length.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5375721&req=5

sensors-17-00435-f010: Energy consumption and the probability of with excavated tunnel length.
Mentions: Figure 10 shows the energy consumed by the sensor tagged on the truck as the length of the tunnel excavation increases. With the given analysis condition, the proposed mobility-aware adaptive duty cycling mechanism consumes less energy than that of the periodic, until the length of the excavated tunnel reaches at 1268 m, in which case the probability is 33.7%. This probability is computed by dividing the truck moving time by the total staying time in the tunnel and corresponds to the value obtained from Equation (6). For the tunnel length, the probability that the proposed mechanism consumes less energy than the periodic one can be computed as:(9)p= TMTM+TS≤(αD+1−D)(β−1)αβ−12·LTunnelvM2·LTunnelvM+TS≤(αD+1−D)(β−1)αβ−1LTunnel≤vM·TS·(αD+1−D)(β−1)2{αβ−1−(αD+1−D)(β−1)} where is the duration of the truck moving, is the stopped time and is the velocity of the moving truck. Note that the excavation face is getting farther away from the tunnel entrance as the tunnel excavation progressed, so the travel distance of the dump truck gets longer. Accordingly, for the proposed adaptive mechanism, the number of duty cycles that use increases with the excavated tunnel length. As a result, the energy consumption increases faster than for the periodic case, which uses .

View Article: PubMed Central - PubMed

ABSTRACT

Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment) and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs) are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.

No MeSH data available.