Jamal-Deen Abdulai

Water Quality Monitoring Using Wireless Sensor Networks: Current Trends and Future Research Directions

Water is essential for human survival. Although approximately 71% of the world is covered in water, only 2.5% of this is fresh water; hence, fresh water is a valuable resource that must be carefully monitored and maintained. In developing countries, 80% of people are without access to potable water. Cholera is still reported in more than 50 countries. In Africa, 75% of the drinking water comes from underground sources, which makes water monitoring an issue of key concern, as water monitoring can be used to track water quality changes over time, identify existing or emerging problems, and design effective intervention programs to remedy water pollution. It is important to have detailed knowledge of potable water quality to enable proper treatment and also prevent contamination. In this article, we review methods for water quality monitoring (WQM) from traditional manual methods to more technologically advanced methods employing wireless sensor networks (WSNs) for in situ WQM. In particular, we highlight recent developments in the sensor devices, data acquisition procedures, communication and network architectures, and power management schemes to maintain a long-lived operational WQM system. Finally, we discuss open issues that need to be addressed to further advance automatic WQM using WSNs.

Improving on the Reliability of Wireless Sensor Networks

The application of wireless sensor networks is gradually gaining popularity in ubiquitous computing. They are used for military surveillance, home automation and monitoring, underwater surveillance, wearable sensor and many others. With their way of deployment and use, these tiny motes are mostly vulnerable to attacks and their mode of transfer of data depletes battery power leaving motes dead after a short while. In this paper an algorithm that can be used to minimize the energy consumed by sensor nodes communicating over multihop links is proposed. The algorithm employs unequal clustering technique taking into consideration the distance of the motes from the base station. Our algorithm considers a base station with sparsely distributed nodes that may not all receive adequate signal strength from the base station. Intuitive performance analysis of the proposed algorithm was done in comparison with EEUC and EAUCF considering their energy metrics and clustering techniques. From the preliminary results obtain, our algorithm performs better than the others and hence more stable and energy efficient clustering algorithm.

Can an Enterprise System Persuade? The Role of Perceived Effectiveness and Social Influence

This study provides an interpretation to empirically explain and predict use continuance intention of students towards an enterprise resource planning (ERP) system. A research model based on the information system continuance, the social identity theory, and the unified theory of acceptance and use of technology was adopted and analyzed using partial least squares structural equation modeling. The analysis uncovered important roles that perceived effectiveness and social influence play in explaining the intention of students to continue using the ERP. Further, the model demonstrated how primary task support contributes to perceived effort, which helps in explaining perceived effectiveness of the system. Computer-human dialogue support significantly contributes to perceived credibility, primary task support and perceived social influence. Social identification of the students significantly predicts perceived social influence. Research related to continuous usage of an ERP system is viable, as it enables designers and developers building more persuasive enterprise and socially influencing systems.

Prolonging the Lifetime of Wireless Sensor Networks: A Review of Current Techniques

There has been an increase in research interest in wireless sensor networks (WSNs) as a result of the potential for their widespread use in many different areas like home automation, security, environmental monitoring, and many more. Despite the successes gained, the widespread adoption of WSNs particularly in remote and inaccessible places where their use is most beneficial is hampered by the major challenge of limited energy, being in most instances battery powered. To prolong the lifetime for these energy hungry sensor nodes, energy management schemes have been proposed in the literature to keep the sensor nodes alive making the network more operational and efficient. Currently, emphasis has been placed on energy harvesting, energy transfer, and energy conservation methods as the primary means of maintaining the network lifetime. These energy management techniques are designed to balance the energy in the overall network. The current review presents the state of the art in the energy management schemes, the remaining challenges, and the open issues for future research work.

Implementation and Evaluation of WLAN 802.11ac for Residential Networks in NS-3

Wi-Fi has been an amazingly successful technology. Its success may be attributed to the fact that, despite the significant advances made in technology over the last decade, it has remained backward compatible. 802.11ac is the latest version of the wireless LAN (WLAN) standard that is currently being adopted, and it promises to deliver very high throughput (VHT), operating at the 5 GHz band. In this paper, we report on an implementation of 802.11ac wireless LAN for residential scenario based on the 802.11ax task group scenario document. We evaluate the 802.11ac protocol performance under different operating conditions. Key features such as modulation coding set (MCS), frame aggregation, and multiple-input multiple-output (MIMO) were investigated. We also evaluate the average throughput, delay, jitter, optimum range for goodput, and effect of station (STA) density per access point (AP) in a network. ns-3, an open source network simulator with features supporting 802.11ac, was used to perform the simulation. Results obtained indicate that very high data rates are achievable. The highest data rate, the best mean delay, and mean jitter are possible under combined features of 802.11ac (MIMO and A-MPDU).

Performance Evaluation of Mobile IP on Mobile Ad Hoc Networks Using NS2

Mobile computing devices equipped with transceivers form Mobile Ad Hoc Networks (MANET) when two or more of these devices find themselves within transmission range. MANETs are stand-alone (no existing infrastructure needed), autonomous networks that utilise multi-hop communication to reach nodes out of transmitter range. Unlike infrastructure networks e.g. the Internet with fixed topology, MANETs are dynamic. Despite the heterogeneous nature of these two networks, integrating MANETs with the Internet extends the network coverage and adds to the application domain of MANETs. One of the many ways of combining MANETs with the Internet involves using Mobile Internet Protocol (Mobile IP) and a MANET protocol to route packets between the Internet and the MANET via Gateway agents. In this paper, we evaluate the performance of Mobile IP on MANET in Network Simulator 2 (NS2). We have implemented Mobile IP on Ad hoc On-demand Distance Vector (AODV), Ad hoc On-demand Multiple Distance Vector (AOMDV) and Destination-Sequenced Distance Vector (DSDV) routing protocols and compared performances based on Throughput, End-to-End Delay (E2ED), Packet Delivery Ratio (PDR) and Normalized Packet Ratio (NPR). The simulation results suggest that on-demand routing within the MANET better serves Mobile IP on MANETs.

Enhancing the Reliability of WSN Through Wireless Energy Transfer

Communication reliability is the ability of the network to last long enough without breaking communication between neighbouring nodes that relay information to the final destination. The transfer of energy from the base station to largely spatially distributed sensor nodes in a network with concurrent data transmission is studied. Concurrent data and energy transfer methods require separation of their frequencies and optimum distance between nodes and Energy Transmitters (ETs). Three techniques of energy transfer: store and forward, direct flow transmission and a hybrid will be explored in an unequal clustering environment for concurrent data and energy transmission. The research seeks to explore the use of energy transmitters augmented with energy transfer techniques that redistribute energy in the network to ensure communication reliability. The need for an optimum energy threshold that will determine whether a node is “fit” to relay energy to neighbouring nodes is investigated.