Secure Full-Duplex Two-Way Relaying for SWIPT

This letter studies bi-directional secure information exchange in a simultaneous wireless information and power transfer (SWIPT) system enabled by a full-duplex (FD) multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay. The AF relay injects artificial noise (AN) in order to confuse the eavesdropper. Specifically, we assume a zeroforcing (ZF) solution constraint to eliminate the residual self-interference (RSI). As a consequence, we address the optimal joint design of the ZF matrix and the AN covariance matrix at the relay node as well as the transmit power at the sources. We propose an alternating algorithm utilizing semi-definite programming (SDP) technique and one-dimensional searching to achieve the optimal solution. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm.Comment: Submitted to IEEE Wireless Communications Letter

Simultaneous wireless information and power transfer in full-duplex communication systems

As wireless devices are mostly constrained by their inability to operate independently infinitely away from centralised power sources, radio frequency (RF) energy harvesting (EH) has been identified as a promising technique for future wireless devices. For this reason, this thesis introduces a novelty in RF EH full-duplex (FD) wireless communication systems. Specifically, this thesis investigate the potentials of simultaneous wireless information and power transfer (SWIPT) in FD communication systems. This thesis firstly focuses on optimal transmit strategies, rate maximization and power minimizing approach for SWIPT in FD systems. Using the rate-split method, difference of convex programming, semi-definite programming technique and one-dimensional search, we reformulate complex optimization problems to yield problem formulations that can be efficiently solved, thus we develop rate maximization algorithm for SWIPT in a point-to-point FD system, SWIPT in FD multiple-input multiple-output (MIMO) two-way relay system and power minimization approach for SWIPT in a multiuser MIMO FD system. This thesis also presents research work carried out with the aim of maximising the secrecy sum-rate for SWIPT in FD systems. In this context, we employ the use of an amplify and forward (AF) relay to inject artificial noise (AN) in order to confuse the eavesdropper. Thus, we address the optimal joint design of the beamforming matrix and AN covariance matrix at the relay, and the transmit power at the sources. Comprehensively, we present extensive theoretical and computer simulations to corroborate the need for joint optimization

Prevalence of gestational diabetes mellitus among pregnant women attending antenatal care services in Diette Koki memorial hospital, Opolo Bayelsa state, Nigeria

Background: Gestational diabetes mellitus is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy. Gestational diabetes which prevalence is on the increase in Nigeria may have negative consequences on the health of the foetus or mother. This study was designed to determine the prevalence of gestational diabetes mellitus and its complications among pregnant women attending antenatal services in Diette Koki memorial hospital Opolo Bayelsa State from 2014-2016.Methods: This was a retrospective study carried out at the Diette Koki Memorial Hospital Opolo in Bayelsa State. The study population comprised pregnant women that attended antenatal care services within the period of January 2014-December 2016. A designed proforma was used to collect the data from the hospital record department.Results: The results of the study showed that the prevalence of gestational diabetes in the year 2014 was 0.023% or 2.33 per 10,000 pregnancies while the prevalence for 2015 was 0.026% or 2.59% per 10000 pregnancies. Furthermore, other complications recorded were hypertension, pre-eclampsia and eclampsia. Similarly, there was a significant correlation between prevalence of gestational diabetes and other complications (r=0.898, p=0.022).Conclusions: In conclusion, prevalence of gestational diabetes was recorded among pregnant women of Diette Koki memorial hospital Opobo Bayelsa State. Therefore, prompt screening and preventive measures should be enforced by health care professionals to prevent maternal and foetal morbidity and mortality

Design and implementation of a transistorized bi-controlled based utility-connected battery charger for underdeveloped nations

This paper presents a transistorized bi-controlled based utility-connected battery charger to address the problem of erratic public power supply in underdeveloped nations. In this study, a utility battery charger was built by the integration of grid power supply, line frequency transformer, power electronic switches, alternating current-direct current bridge converter, regulator, and resistor-inductor-capacitor. The excess-voltage protection and battery monitoring were obtained by the bi-controlled technique. In contrast to other charging systems in underdeveloped nations, the proposed system is very simple, rugged, reliable and cheap to maintain due to simplicity and un-programmed nature of the system. The results showed that the proposed system is craggy and robust to resist voltage stress, highly reliable and relatively free from leakage currents due to the presence of a double controlled scheme using a common point of action and a line frequency transformer. In addition, the system can be used to charge batteries ranging from 50μA and above. The system can be utilized in communication companies, electric vehicles, drilling machines

Internet of Things (IoT) Cloud Based Model for Low Cost Demand Side Management Infrastructure

This paper presents a model for low cost demand side management infrastructure using cloud-based technology and internet of things to facilitate the implementation of smart grid in Nigeria. The electricity market has experienced a rapid increase in demand attributed to unprecedented growth in human population, urbanization, and industrialization. Accordingly, utilities are faced with the challenge of meeting daily energy demand. Research has shown that 45% of electricity generated are wasted or cannot be accounted for. Energy management is thus a major issue affecting the power sector of Nigeria. Efficient utilization of energy is therefore crucial for sustainable development both from an economic and ecological perspective. The proposed Smart, Low Cost and IoT-enabled power distribution board can be adopted and implemented as part of energy conservation measures to reduce energy demand in domestic building and mitigate the energy crisis in the country. With the IoT based smart board energy management, users can get personalized recommendation of actions for energy conservation and load shifting, and have control over the energy use and the billing system

Off-Grid mobile phone charging systems for rural energy needs

For several decades, rural electrification has remained a formidable challenge, particularly in Nigeria. Financial constraints, difficult rural terrain, inefficient policy, and a lack of industrial community development have all contributed to the grid expansion problem in these areas. These areas are energy-deficient, and their energy demands to keep up with cutting-edge communication technology are constantly rising. As a result, rural areas are confronted with the issue of charging. Consequently, many rural residents are forced to rely on diesel/petrol generators or travel long distances and pay a premium to have their mobile phones charged. Thus, this paper proposes an off-grid solar-powered charging system as an alternative, sustainable solution to meet rural mobile phone energy demand. The methodology employed six-tier architectural features, with the economic comparison metric based on net present value and payback period. Furthermore, the proposed model's performance analysis revealed that the charging rate is dependent on the phone battery type and charger type. Furthermore, the off-grid mobile charging system has a higher net present value ($20,658US) and a shorter payback period of 2.5 years than the alternative investment of a gasolne generator

Anatomical studies on the spinal cord of the greater cane rat (Thryonomys swinderianus, Temminck) II: histomorphology and spinal tracings

The field of neuroanatomy and the knowledge of spinal cord, in particular, requires an accurate base on which data can be mapped. Lately, researchers have taken into consideration studies on Greater cane rat (GCR) because of its large body size and African origin. This study was designed to elucidate the histomorphologic features of the GCR spinal cord. A total of 10 adult GCR (five males and five females) raised in captivity were used for this study. Twenty-seven spinal segments (Cervical-8, Thoracic-13, Lumbar-5 and Sacral-1) were identified. Each segment was transected, processed histologically into Nissl-stained sections and observed features of the spinal cord were described. The GCR spinal segments possess the typical Hshaped inner gray matter core surrounded by an outer white matter. Variations in the shape of the central canals were observed across the spinal segments. A total of sixty-four features were delineated: twelve observed in the white matter, forty-nine in the gray matter and the remaining three were attached to the spinal cord. Laminar organisations, tracts, nuclei and motor neuron groups of the spinal cord identified were also traced and possible functions adduced in this rodent. No sexual dimorphism was observed in this study. This work has provided valuable and qualitative baseline information for understanding the laminar characteristics relevant to pathophysiologic conditions of the spinal cord. It has also contributed to the knowledge of neuroanatomy of this rodent and will be valuable for spinal cord research especially in this species.Keywords: Spinal cord, Greater cane rat, Histology, Laminar organisation, Spinal tracing

Secure full-duplex two-way relaying for SWIPT

This letter studies bi-directional secure information exchange in a simultaneous wireless information and power transfer (SWIPT) system enabled by a full-duplex (FD) multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay. The AF relay injects artificial noise (AN) in order to confuse the eavesdropper. Specifically, we assume a zeroforcing (ZF) solution constraint to eliminate the residual self-interference (RSI). As a consequence, we address the optimal joint design of the ZF matrix and the AN covariance matrix at the relay node as well as the transmit power at the sources. We propose an alternating algorithm utilizing semi-definite programming (SDP) technique and one-dimensional searching to achieve the optimal solution. Simulation results are provided to demonstrate the effectiveness of the proposed algorithm