Design and implementation of a wearable gas sensor network for oil and gas industry workers

Industrial environment usually involves some types of hazardous substances including toxic and/or flammable gases. Accidental gas leakage can cause potential dangers to a plant, its employees and surrounding neighborhoods. Around 64% of accidents that happen in the oil fields are due to combustibles and/or toxic gases. The safety plan of most industries includes measures to reduce risk to humans and plants by incorporating early-warning devices, such as gas detectors. Most existing tools for monitoring gases are stationary and incapable of accurately measuring individual exposures that depend on personal lifestyles and environment. This paper provides a design and implementation of a wearable gas sensor network by building sensor nodes with wireless communication modules which communicate their data along the network. The system is designed to be flexible, low cost, low maintenance and with accurate performance to detect toxic gases in a timely fashion to warn employees before an existence of a disaste

Packet Reservation Multiple Access (PRMA) with Random Contention

Packet reservation multiple access (PRMA) can be considered as a merge of slotted ALOHA protocol and time division multiple access (TDMA) protocol. Independent terminals transmit packets to base station by contending to access an available time slots. A terminal that succeeds in reserving a certain time slot keeps on this reservation for transmitting its subsequent packets. Speech activity detection is used in PRMA to improve system capacity. In this work we propose a simpler contention mechanism that does not depend on a predetermined permission probability as in the original PRMA. In the new method, terminals select the contention slot uniformly from the pool of remaining free slots in the current frame. We evaluate the performance of the new contention mechanism in terms of various metrics including maximum number of carried voice calls and packet delays for a given acceptable drop rate of voice packets. We show that the new mechanism is superior to that of the original PRMA for loaded systems and is expected to be insensitive for traffic source burstiness

A Web-Based Application of TELOSB Sensor Network

Sensor network can be used in a numerous number of applications. However, implementing wireless sensor networks present new challenges compared with theoretical networks. In addition, implementing a sensor network might provide results different from that derived theoretically. Some routing protocols when implemented might fail to perform. In this paper, we implement three routing protocols, namely: Dynamic MANET on-demand, Collection Tree and Dissemination protocols. To compare the performance of these protocols, they are implemented using a Telosb sensor network. Several performance metrics are carried out to demonstrate the pros and cons of these protocols. A telemedicine application is tested in top of the implemented Telosb sensor network at King Fahd University of Petroleum and Minerals Clinic in Saudi Arabia, utilizing Alive ECG sensors

A contention free multi-channel MAC protocol with improved negotiation efficiency for wireless ad-hoc networks

In this paper we present an Improved Contention-Free Multi-Channel Medium Access Control protocol (ICM-MAC) for wireless Ad-hoc networks. The proposed MAC is based on split phase approach, and uses a single transceiver. Channel negotiations are done on a predefined channel that is used for both control and data transmissions. Nodes contend to get access to the contention free data period based on their knowledge of their neighbors’ activities and the availability of free channels. We evaluate the proposed MAC via simulation and compare with the Multi-channel MAC protocol (MMAC) and Progressive Back Off Algorithm (PBOA) algorithms

Adaptive ACK: A novel intrusion detection system to mitigate intended packet dropping in MANETs

Unlike infrastructure wireless networks, mobile ad-hoc network (MANET) is an infrastructureless network where self-configuring mobile nodes connected by wireless links. Because of its decentralized property, these nodes relay on each other to store and forward packets. Most of the proposed MANET protocols assume cooperative behavior among its nodes. However, some nodes may exhibit different behaviors such as selfish. Thus, misbehaving nodes can disrupt the network operation and affect the network availability by refusing to cooperate to route packets due to their selfish or malicious behavior. Towards this end, this paper proposes a novel intrusion detection system. An adaptive acknowledgment scheme (AACK) is proposed to detect and exclude such misbehaving nodes. This scheme is developed to overcome watchdog weaknesses due to collisions and limited transmission power. To demonstrate the performance of our proposed scheme, simulation experiments are performed. The simulation results show that AACK scheme provides better network performance with less overhead than some existing DSR-based systems such TWOACK and Watchdog