To bring VANET into reality, it is crucial to devise routing protocols that can exploit the inherited characteristics of VANET environment to enhance the performance of the running applications. ...Previous studies have shown that a certain routing protocol behaves differently under different presumed mobility patterns. Bypass-AODV is a new optimization of the AODV routing protocol for mobile ad-hoc networks. It is proposed as a local recovery mechanism to enhance the performance of the AODV routing protocol. It shows outstanding performance under the Random Waypoint mobility model compared with AODV. However, Random Waypoint is a simple model that may be applicable to some scenarios but it is not sufficient to capture some important mobility characteristics of scenarios where VANETs are deployed. In this paper, we will investigate the performance of Bypass-AODV under a wide range of mobility models including other random mobility models, group mobility models, and vehicular mobility models. Simulation results show an interesting feature that is the insensitivity of Bypass-AODV to the selected random mobility model, and it has a clear performance improvement compared to AODV. For group mobility model, both protocols show a comparable performance, but for vehicular mobility models, Bypass-AODV suffers from performance degradation in high-speed conditions.
This article focuses on cyber-physical systems involving a set of robots and sensors that are interconnected through wireless links. In applications that operate in harsh environments, wireless ...sensors and robot networks (WSRNs) may suffer simultaneous failures, which lead to partitioning the WSRN into unconnected subnetworks. The loss of connectivity often leads to degrade performance and inability to fulfill the application mission. To address this issue, several proposals have been made in the literature where node mobility is exploited to re-establish connectivity. These proposals, however, focus on minimizing the number of mobile nodes and the traveled distance cost while ignoring important factors, such as robot battery level, network lifetime, and environmental conditions, that may limit or hinder the whole recovery process. To overcome these limitations, we present a distributed node repositioning algorithm based on fuzzy logic. We evaluate our approach via extensive simulations and prototype experiments using Khepera IV robots. The results demonstrate superior performance to that of contemporary approaches.
Auction-based and threshold-based are the prevalent approaches for multi-robot distributed task allocation problem. We study the performance of these two approaches under a multi-objective dynamic ...task allocation scenario. The fuzzy inference system (FIS) is used in the auction-based approach to convert the objectives into a representative bid value. Experiments reveal that FIS auction-based outperforms the adaptive threshold-based approach in terms of load balancing. In contrast, the adaptive threshold-based approach produces better results in terms of traveled distance. Moreover, both approaches can achieve the same quality satisfaction objective.
Autonomous robot deployment is very attracting feature especially inside unknown area. Virtual force (VF) technique appears as one of the prominent approaches to performing multirobot deployment ...autonomously. However, most of the existing VF-based approaches lack purposeful deployment. In this work, we present a Cooperative Virtual Force Robot Deployment (COVER) technique. Our approach modifies the original VF approach to overcome this problem and considers the mission requirements such as the number of required robots in each locality (e.g., landmarks are distributed, and each needs a specific number of robots in its vicinity). In addition, COVER expedites the deployment process by establishing a cooperative relation between robots and neighboring landmarks. Extensive simulation experiments have been carried out to assess the performance of COVER along with Hungarian deployment method (a centralized approach), the basic virtual force, and full virtual force. A proof of concept experiment using TurtleBot robots is presented as well to show real implementation of COVER. The simulation and experiment results demonstrate the effectiveness of COVER for several performance factors such as total traveled distance, total exchanged messages, and total deployment time.
Mobile applications have been increasingly adopted in monitoring and tracking systems such as health tracking systems for elderly and chronic patients. Due to the ubiquitous nature of smartphones, ...using smartphones in such tracking systems would be time and cost-effective. However, the limited battery capacity in smartphones could cause an interruption in reporting the tracking information, especially when users spend a long time without recharging batteries. Continuous tracking could be critically important, especially for the elderly and patients with serious illnesses. In this paper, we develop a mobile application for Android smartphones that report the location and health information cooperatively using the CEET clustering protocol. On the server-side, we exploited the Google Firebase real database that receives the users’ tracking information and can notify the data changes within milliseconds. We present a performance evaluation of the system through real experiments using the developed application. The results show the outstanding performance of the proposed approach in reducing the tracking energy (by around 55%). The developed app does not require any modification neither to the manufacturing specifications of the smartphones nor to the established wireless environment. The user just needs to install the app to his/her smartphones using apk file or from the Google play.
Consider a set of landmarks that are distributed in an emergency scene and each needs a specific number of robots in its vicinity. This paper presents a two-stage framework for deploying robots ...autonomously for such scenarios. In the first stage, a Two-hop Cooperative Virtual Force Robot Deployment (Two-hop COVER) technique is employed. It expedites the deployment process by establishing a cooperative relationship between robots and neighboring landmarks. Two-hop communication is utilized as well to reduce the deployment time and traveled distance by robots to satisfy the mission requirements and optimize the deployment process. However, in certain scenarios, Two-hop COVER may not achieve full demand satisfaction. Therefore, the second stage, called Trace Fingerprint is invoked to guarantee full satisfaction. Finally, a fairness-aware version of Two-hop COVER is presented to consider scenarios in which the mission requirements are greater than the available resources (i.e. robots) and hence, the fairness-aware approach dispatches robots in proportion to each landmark's need. Extensive simulation experiments have been carried out to assess the performance of the proposed framework. The simulation results demonstrate the effectiveness of the proposed approaches considering several performance factors, such as total travelled distance, total exchanged messages, total deployment time, and Jain's fairness index.
Today's smart grid faces many challenges due to the rapid evolution of generation, distribution, and storage means which enable users to produce, store, and sell energy back to the providers. Demand ...response management plays a key role in achieving the objective of balancing electricity supply and demand efficiently. It also helps leveling consumption during peak hours. To do so, this paper proposes a game theoretic model for the multiperiodic smart grid demand side management problem with shifted demand. The proposed model has two major sets of players: Homeowners and electricity providers. We develop a 0-1 mixed linear programming approach to compute the Nash equilibria of the proposed game. We analyze the structure of the Nash equilibria to maintain the viability of the smart grid infrastructure. We also discuss the order relations between the users and the providers utility coefficients. Finally, we conduct extensive experiments on smart grid demand response synthetic data with different size. The obtained results demonstrate the scalability of the proposed game model.
Smart grid is one of the major prospective candidates in the Industrial Internet of Things family that ensures smooth and efficient power distribution, restoration in times of emergency, and usage ...control for the consumers. Electric power generators contribute at the core of smart grid along with the transmission lines and transformers. Extensive research works are conducted to optimize different parameters such as efficient energy usage, automated demand response, and emergency grid failure recovery. However, the component status analysis of the electric generators within a smart grid is still in the nascent stage. In this paper, we propose a novel routing protocol for supervised device-data transfer from smart grid generators to the command and control center using wireless ad hoc and sensor networks. Our protocol assumes various sensor devices (temperature sensors, oil level sensor, turbine status sensors, etc.) to be employed on each generator due to their mechanical sophistication. Additionally, we introduce the ambient energy harvesting for the sensors energy replenishment to accommodate tolerable node outage. Our simulation results demonstrate promising outcome with respect to different key parameters such as message flow, energy consumption, outage frequency, remaining energy, and harvested energy.
This paper considers the problem of assigning target locations to be visited by mobile robots. We formulate the problem as a multiple-depot multiple traveling salesman problem (MD-MTSP), an NP-Hard ...problem instance of the MTSP. In contrast to most previous works, we seek to optimize multiple performance criteria, namely the maximum traveled distance and the total traveled distance, simultaneously. To address this problem, we propose, FL-MTSP, a new fuzzy logic approach that combines both metrics into a single fuzzy metric, reducing the problem to a single-objective optimization problem. Extensive simulations show that the proposed fuzzy logic approach outperforms an existing centralized Genetic Algorithm (MDMTSP_GA) in terms of providing a good trade-off of the two performance metrics of interest. In addition, the execution time of FL-MTSP was shown to be always faster than that of the MDMTSP_GA approach, with a ratio of 89 %.
Structural and industrial environments use hundreds to thousands of bolts to hold parts together. For most mechanical systems, the bolts are critical components because they are subject to axial ...tension triggering various failures; for example, compromised screw threadsand/or vibration caused untightening. Severe damages can result injury of personnel, equipment damage, and even loss of life. Typically, monitoring mechanical tension of the bolts is visually performed with red dot bolts or manually inspected, but this process is expensive in terms of effort, time, and money; additionally, perhaps the accessibility of the bolt itself is very difficult. Changing this tedious monitoring process to automated, quick, and precise process is our concern in this work. Nowadays, wireless sensor networks (WSN) have wide range of applications especially in surveillance and monitoring systems. In this paper, we propose an efficient and power-aware technique to monitor bolted joints using wireless sensor networks. Also, due to the randomization placement of bolts in real world, our proposed mechanisms have been studied with different deployment node distributions (grid, uniform, normal, and exponential). Furthermore, we have investigated different scenarios with different probability of bolt failures to explore their effect on power consumption and network lifetime.
PDF
