154 research outputs found
On The Comparative Analysis Of Beta And Kumaraswamy Priors Using Stigmatized Attributes
Hussain et al 2011 compared bayes estimator of population proportion of a stigmatized attribute with the Maximum Likelihood Estimator (MLE) but this paper compares two priors: beta and kumaraswamy in the Bayesian analysis using various values of n, x, p1 and p2 and it was observed that across the sample sizes considered over different values of x’s, p1 and p2 using R package software for simulation, the mean square error and bias of the Kumaraswamy prior are smaller than that of Beta prior when the proportion of stigmatized attribute increases from 0.1 to 0.4 Keyword: Prior, Beta, kumaraswamy, Stigmatized, Attribut
Experimental Assessment of Cellular Mobile Performance along the Railway Corridor
With the ongoing rehabilitation of the railway transportation sector in Nigeria, improvement in the quality and reliability of the services deliverable becomes crucial. Reliable railway communication infrastructure guarantees effective operation and also ensures connectivity for security, safety, maintenance and passenger communication. This work describes today’s network scenario by assessing current cellular performance as it affects a passenger’s experience along the railway corridor. A drive test was conducted on the 6th of July, 2014 between 12:58pm and 07:14pm along the railroad linking Oshogbo and Lagos, Nigeria. The measurement setup consists of four TEMS Mobile Sony Ericsson W995 phones, a Personal Computer, a GPS receiver, and a power bank. The measurement was useful in the assessment of coverage, capacity and Quality of Service (QoS) of four mobile radio networks namely: Airtel, Globacom, Etisalat and MTN in the GSM 900 MHz and 1800 bands. Results reveal that no single mobile network service operator consistently serviced the train throughout the 6-hour trip. Also, the results obtained from the drive test represents a true picture of mobile network condition and can be useful in decision making in several areas - from planning and design through optimization and maintenance of the system, with the goal of maximizing quality, capacity and coverage for all mobile networks for improved service delivery on our railway infrastructure.
Keywords: Railway communication; GSM; Performance of Cellular mobil
Experimental Assessment of Cellular Mobile Performance along the Railway Corridor
With the ongoing rehabilitation of the railway transportation sector in Nigeria, improvement in the quality and reliability of the services deliverable becomes crucial. Reliable railway communication infrastructure guarantees effective operation and also ensures connectivity for security, safety, maintenance and passenger communication. This work describes today’s network scenario by assessing current cellular performance as it affects a passenger’s experience along the railway corridor. A drive test was conducted on the 6th of July, 2014 between 12:58pm and 07:14pm along the railroad linking Oshogbo and Lagos, Nigeria. The measurement setup consists of four TEMS Mobile Sony Ericsson W995 phones, a Personal Computer, a GPS receiver, and a power bank. The measurement was useful in the assessment of coverage, capacity and Quality of Service (QoS) of four mobile radio networks namely: Airtel, Globacom, Etisalat and MTN in the GSM 900 MHz and 1800 bands. Results reveal that no single mobile network service operator consistently serviced the train throughout the 6-hour trip. Also, the results obtained from the drive test represents a true picture of mobile network condition and can be useful in decision making in several areas - from planning and design through optimization and maintenance of the system, with the goal of maximizing quality, capacity and coverage for all mobile networks for improved service delivery on our railway infrastructure
Hybrid algorithm for NARX network parameters' determination using differential evolution and genetic algorithm
A hybrid optimization algorithm using Differential Evolution (DE) and Genetic Algorithm (GA) is proposed in this study to address the problem of network parameters determination associated with the Nonlinear Autoregressive with eXogenous inputs Network (NARX-network). The proposed algorithm involves a two level optimization scheme to search for both optimal network architecture and weights. The DE at the upper level is formulated as combinatorial optimization to search for the network architecture while the associated network weights that minimize the prediction error is provided by the GA at the lower level. The performance of the algorithm is evaluated on identification of a laboratory rotary motion system. The system identification results show the effectiveness of the proposed algorithm for nonparametric model development
Detection of vascular intersection in retina fundus image using modified cross point number and neural network technique
Vascular intersection can be used as one of the symptoms for monitoring and diagnosis of diabetic retinopathy from fundus images. In this work we apply the knowledge of digital image processing, fuzzy logic and neural network technique to detect bifurcation and vein-artery cross-over points in fundus images. The acquired images undergo preprocessing stage for illumination equalization and noise removal. Segmentation stage clusters the image into two distinct classes by the use of fuzzy c-means technique, neural network technique and modified cross-point number (MCN) methods were employed for the detection of bifurcation and cross-over points. MCN uses a 5x5 window with 16 neighboring pixels for efficient detection of bifurcation and cross over points in fundus images. Result obtained from applying this hybrid method on both real and simulated vascular points shows that this method perform better than the existing simple cross-point number (SCN) method, thus an improvement to the vascular point detection and a good tool in the monitoring and diagnosis of diabetic retinopathy
ENGINEERING AND GEOLOGICAL EVALUATION OF ROCKS FOR CONCRETE PRODUCTION
Engineering and geological properties of rocks from eight different quarries in Ibadan were evaluated to determine their suitability for concrete production. Samples from each quarry sites were subjected to grading, relative density, water absorption, bulk density, amount of materials finer than 75ÎĽm, flakiness and elongation Index, Aggregate Impact Value (AIV), Aggregate Crushing Value (ACV), Aggregate Abrasion Value (AAV), 10% fines value and petrographical analysis adopting BS testing methods. The relationship between engineering properties with one another and the petrographical characteristics were described by Pearson correlation coefficient and bar charts. The results of engineering analysis revealed that rocks from all the quarries are generally sound and good because of their possession of necessary characteristics for use in concrete production when compared with British (BS), Indian (IS) and American Society for Testing and Materials (ASTM) standards. Petrographical analyses revealed that samples which have performed better in all the engineering tests possess higher content of quartz mineral and finer texture. Statistically significant correlations were found among the tests performed
EFFECTS OF COOKING CONDITIONS ON THE TEXTURE PROFILE, SENSORY AND PROXIMATE QUALITIES OF PRESSURE COOKED BAMBARA NUTS
This study evaluated the effects of pressure cooking on the textural attributes of Bambara nuts using Response Surface Methodology (RSM).The study optimized cooking condition {Weight of Bambara (250 – 1000g), cooking time (20 -90 min) and post cooking resident time (2-12 min)} for the pressure boiling on the textural and qualities of Bambara. Five out of the eleven optimised solutions (Desirability Index range of 0.919 to 0.936) were compared with samples from conventionally boiled Bambara for proximate and sensory (colour, texture, aroma and Overall acceptance) qualities. Data were analysed using RSM, analysis of variance and PPMC. Models for hardness, springiness, cohesiveness, fracturability and sensory texture with adjusted R2 values of 83.41%, 80.99%, 67.37% , 93,75% and 88.96% respectively adequately explained the textural and sensory qualities of boiled bambara. The range of values for moisture, fat, ash, crude protein and carbohydrate were 47.88, 2.24, 1.98, 24.30, 20.91 % to 50.58, 2.58, 2.19, 25.49, 21.87% respectively. Boiled Bambara produced at verified optimisation solutions (527.62g, 82.55, 10.43 min and 591.69g, 82.96, 9.52 minutes) were not significantly different (p >0.05) from that produced by conventional method (weight and Cooking time: 500g and 125 min.) in spite of the relatively longer cooking time of the later.
 
Domestic groundwater abstraction in Lagos, Nigeria: a disjuncture in the Science-Policy-Practice Interface?
The rapid development of groundwater systems as part of urban water supplies around the globe is raising critical questions regarding the sustainable management of this essential resource. Yet, in many major cities, the absence of an effective policy regime means that the practice of groundwater exploitation is driven by the actions of domestic households and drilling contractors. Understanding what shapes the decisions and practices of these actors, their understandings of the groundwater resource and the extent to which scientific knowledge shapes this understanding, is an area of critical importance that is currently under-researched. Using a mixed-methods methodology, the paper explores domestic practices of groundwater abstraction in Lagos, Nigeria. It finds that there is a disjuncture between the households who are actively shaping exploitation of the groundwater resource on a day-to-day basis and science and state actors. This disjuncture results in household decisions that are influenced by commonly held, but potentially outdated, perceptions of the groundwater resource rather than scientific evidence or policy instruments. The unseen nature of groundwater resources effectively renders the scale of changing groundwater conditions invisible to households and the state, adding to the challenge of influencing practice. Addressing this disjuncture requires not just more scientific knowledge, but also the active construction of interfaces with, and between, non-state actors through which knowledge can be confronted, discussed and shared
Resilience in groundwater supply systems: integrating resource based approaches with agency, behaviour and choice
Access to safe and reliable water supplies is a key goal for households and governments across most of Africa.
Groundwater reserves can play a critical role in achieving this, yet risks of contamination and over-abstraction threaten to undermine the resilience of this supply. A rapidly rising trend for privately-developed wells and boreholes raises additional concerns about the vulnerability of water supplies to natural or man-made environmental shocks. The potential scale of the situation is particularly marked in Nigeria where the use of boreholes has increased exponentially since 1999 (from 10% of the population to 38% in 2015), with most other forms of water supply, notably piped tap water, falling.
Developing effective groundwater management approaches that build the resilience of communities is challenging, not least given the range of different actors involved, their competing interests and demands, and variations in the hydrogeological environment.
Insights from resilience studies in social science emphasise how the resilience of ecological resources to shocks and change is critically linked to the adaptive capacity of social systems and their agents. Choices made now have long-lasting effects, yet these choices are little understood.
Understanding the choices made by consumers, drillers and policy actors requires a strong interdisciplinary dimension and argues for new perspectives as to how the resilience of communities and societies might be built.
The project brings together a unique interdisciplinary collaboration between academics from the UK and Nigeria working in the fields of economic geography, psychology, hydrogeology and journalism studies
Individual water sourcing: understanding risks and resilience to groundwater resource abstraction in Nigeria
Across much of Africa, domestic water supplies are increasingly dependent on groundwater reserves. As
the cost of accessing these reserves fall, expertise becomes more widely available and incomes rise there
is a rising trend towards the private commissioning of boreholes and wells. This nascent shift towards a
distributed and increasingly individualised water supply may have many implications for the resilience of
communities to future environmental shocks, which are, as yet, under-explored. Drawing on the case of
Nigeria and new interdisciplinary research, this paper addresses this gap, through a specific focus on
understanding the behaviour and choices of individuals and other key stakeholders which underpin this
trend. It also seeks to understand the possible implications of this for the resilience of associated social
and ecological systems
- …