School of Physical and Mathematical Sciences
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Browsing School of Physical and Mathematical Sciences by Author "Abdulai, J.D."
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Item Face detection based on multilayer feed‐forward neural network and Haar features(Software - Practice and Experience, 2019-01) Owusu, E.; Abdulai, J.D.; Zhan, Y.Fast and accurate detection of a facial data is crucial for both face and facial expression recognition systems. These systems include internet protocol video surveillance systems, crime scene photographs systems, and criminals' databases. The aim for this study is both improvement of accuracy and speed. The salient facial features are extracted through Haar techniques. The sizes of the images are reduced by Bessel down-sampling algorithm. This method pre- served the details and perceptual quality of the original image. Then, image normalization was done by anisotropic smoothing. Multilayer feed-forward neural network with a back-propagation algorithm was used as classifier. A detection accuracy of 98.5% with acceptable false positives was registered with test sets from FDDB, CMU-MIT, and Champions databases. The speed of exe- cution was also promising. An evaluation of the proposed method with other popular detectors on the FDDB set shows great improvement.Item Framework for time relevant water monitoring system(Computing in Research and Development in Africa: Benefits, Trends, Challenges and Solutions, 2015) Katsriku, F.A.; Wilson, M.; Yamoah, G.G.; Abdulai, J.D.; Rahman, B.; Grattan, K.The emergence of telecommunications in the last decade and advances in the field of instrumentation have enabled many new applications to be developed in particular for remote monitoring of physical environment by sensors spatially distributed. A framework for water quality monitoring is been proposed based on a telecommunications infrastructure. In this proposal, we review some of the benefits that may be derived by developing nations and key challenges that need to be addressed in the monitoring of water quality for rural communities in Africa. It is proposed that Fibre Optic Sensors can be used to design compact and highly efficient sensor systems. The proposed framework may be extended to other areas of national economic importance. © Springer International Publishing Switzerland 2015.Item Implementation and Evaluation of WLAN 802.11ac for Residential Networks in NS-3(Journal of Computer Networks and Communications, 2018-03) Amewuda, A.B.; Katsriku, F.A.; Abdulai, J.D.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).Item A modifed distance‑based energy‑aware (mDBEA) routing protocol in wireless sensor networks (WSNs)(Springer, 2022) Abdulai, J.D.; Adu‑Manu, K. S.; Katsriku, F. A.; Engmann, F.Wireless sensor networks (WSNs) are used to collect data and detect phenomena in a real-time environment. There is considerable interest in the deployment of WSNs in remote, inaccessible and inhospitable locations; such use of WSNs throws up many challenges. WSNs come with numerous advantages, yet a notable limitation is that the battery life dictates the lifetime of the sensor node. Two critical factors that determine battery lifetime are the frequency of sensor readings and the transmission range of the sensor nodes. Some energy-efficient routing protocols have been proposed and adopted for use to extend the lifetime of sensor nodes. These protocols aim at optimizing the routes in the network. Given that multi-hop routes are energy ineficient, improving the lifetime of WSNs in a multi-hop routing environment will require the use of route optimization techniques. A modified distance-based energy-aware (mDBEA) routing protocol is proposed which is efficient and capable of minimizing the energy consumption of the sensor nodes and hence, maximizing network lifetime. Our approach addresses the problem by calculating the Euclidian distance between successive nodes to determine the short est distance that minimizes the energy required for transmission. The simulation results indicate that the mDBEA routing protocol reduced the amount of energy consumed in the network by choosing the minimum transmission distance between the source and its neighbour nodes that significantly prolonged the network's lifetime. Our greedy approach yielded about 95% Packet delivery ratio (PDR). Our next-hop and the direct-to-sink algorithms yielded about 82% PDR.Item Prolonging the Lifetime of Wireless Sensor Networks: A Review of Current Techniques(Wireless Communications and Mobile Computing, 2018-08) Engmann, F.; Katsriku, F.A.; Abdulai, J.D.; Adu-Manu, K.S.; Banaseka, F.K.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.Item Signal Propagation Models in Soil Medium for the Study of Wireless Underground Sensor Networks: A Review of Current Trends(Hindawi, 2021) Banaseka, F.K.; Katsriku, F.; Abdulai, J.D.; Adu-Manu, K.S.; Engmann, F.N.A.Radio signal propagation modeling plays an important role in the design of wireless communication systems. Various models have been developed, over the past few decades, to predict signal propagation and behavior for wireless communication systems in different operating environments. Recently, there has been an interest in the deployment of wireless sensors in soil. To fully exploit the capabilities of sensor networks deployed in soil requires an understanding of the propagation characteristics within this environment. This paper reviews the cutting-edge developments of signal propagation in the subterranean environment. The most important modeling techniques for modeling include electromagnetic waves, propagation loss, magnetic induction, and acoustic wave. These are discussed vis-a-vis modeling complexity and key parameters of the environment including electric and magnetic properties of soil. An equation to model propagation in the soil is derived from the free space model. Results are presented to show propagation losses and at different frequencies and volumetric water content. The channel capacity and the operating frequency are also analyzed against soil moisture at different soil types and antenna sizes.