Fabrication of Polymeric Multimode Waveguides for Application in the Local Area Network and Optical Interconnects.

We report the fabrication of multimode polymeric waveguides using spin coating, photolithography, and reactive ion etching. Different layer structures have been used, e.g., a UV curable resin is used as a core layer and PMMA as a lower and upper cladding. The layer systems can be spun with good uniformity with thicknesses matching multimode fiber dimensions, and smooth waveguide side-walls have been obtained after etching. The measured performance of these waveguides demonstrates that low-loss waveguides can be fabricated cheaply. The waveguides are used in the realization of novel compact multimode power splitters and star couplers

Design and fabrication of 1xN and NxN planar waveguide couplers for multimode fiber-based local area networks.

We report on the design and fabrication of compact and potentially low-cost multimode fiber matched 1 x N and N x N couplers for LAN’s. The design utilizes the self-imaging effect and tapering of the Multi-Mode Interference (MMI) section. An extended mode propagation analysis and 3-D beam propagation method (BPM) were used to analyze and design these structures. The simulations show that the couplers exhibit low excess losses, low power imbalance, and relaxed fabrication tolerances at very short device length. The devices were fabricated in polymer waveguide technology using spin coating, photolithography, and reactive ion etching. Preliminary experimental results show promising characteristics

Knowledge Discovery in Online Repositories: A Text Mining Approach

Before the advent of the Internet, the newspapers were the prominent instrument of mobilization for independence and political struggles. Since independence in Nigeria, the political class has adopted newspapers as a medium of Political Competition and Communication. Consequently, most political information exists in unstructured form and hence the need to tap into it using text mining algorithm. This paper implements a text mining algorithm on some unstructured data format in some newspapers. The algorithm involves the following natural language processing techniques: tokenization, text filtering and refinement. As a follow-up to the natural language techniques, association rule mining technique of data mining is used to extract knowledge using the Modified Generating Association Rules based on Weighting scheme (GARW). The main contributions of the technique are that it integrates information retrieval scheme (Term Frequency Inverse Document Frequency) (for keyword/feature selection that automatically selects the most discriminative keywords for use in association rules generation) with Data Mining technique for association rules discovery. The program is applied to Pre-Election information gotten from the website of the Nigerian Guardian newspaper. The extracted association rules contained important features and described the informative news included in the documents collection when related to the concluded 2007 presidential election. The system presented useful information that could help sanitize the polity as well as protect the nascent democracy

Building a Multimodal, Trust-Based E-Voting System

This paper addresses the issue of voter identification and authentication, voter participation and trust in the electoral system. A multimodal/hybrid identification and authentication scheme is proposed which captures what a voter knows – PIN, what he has – smartcard and what he is – biometrics. Massive participation of voters in and out of the country of origin was enhanced through an integrated channel (kiosk and internet voting). A multi-trust voting system is built based on service oriented architecture. Microsoft Visual C#.Net, ASP.Net and Microsoft SQL Server 2005 Express Edition components of Microsoft Visual Studio 2008 was used to realize the Windows and Web-based solutions for the electronic voting system

5kVa power inverter design and simulation based on boost converter and H-bridge inverter topology

Five (5) kVA power inverter was designed and simulated base on two topologies; Boost converter and Half-bridge inverter topology. A 555 timer IC was used as the control at fixed frequencies of 25 kHz and 50 Hz for the two stages. The results of the simulation were obtained. The graphs for both stages were plotted and the results show a significant increase in the voltage and duty cycle. The wave form of the output gives a square wave form. Keywords: Power inverter, Simulation, Topology, Converte

An Approach to Reaeration Coefficient Modeling in Local Surface Water Quality Monitoring

Reaeration coefficient (k2) for River Atuwara, Ogun State, Nigeria was calculated from dissolved oxygen and biochemical oxygen demand data collected over period of 3 months covering the two prevailing climatic seasons in the country. Both the Akaike and Bayesian information criteria were used in the selection and analysis of ten models to identify the most suitable reaeration coefficient (k2) model for Atuwara River. Models that passed the confidence limit were subjected to model evaluation using measures of agreement between observed and predicted data such as percent bias, Nash–Sutcliffe efficiency, and root mean square observation standard deviation ratio. The used approach yield better results than empirical models developed for local conditions while it is also useful in conserving scarce resources

A fuzzy expert system (FES) tool for online personnel recruitments

The advent of the internet has facilitated greater access to the myriad of job opportunities available globally. Currently there exist many job application submission portals that are being used for online job recruitment purposes. However, the task of many of these job submission portals is limited to matching the professional and academic qualifications of applicants with the requirements of employers and several organisations and does not involve the ranking of applicants’ credentials according to their relative suitability for the jobs applied for. In this paper, we describe the implementation of fuzzy expert system (FES) tool for selection of qualified job applicants with the aim of minimising the rigour and subjectivity associated with the candidate selection process. A performance evaluation of the FES tool that was conducted confirmed the viability of a FES-based approach in handling the fuzziness that is associated with the problem of personnel recruitment

An Approach to Reaeration Coefficient Modeling in Local Surface Water Quality Monitoring

Reaeration coefficient (k2) for River Atuwara, Ogun State, Nigeria was calculated from dissolved oxygen and biochemical oxygen demand data collected over period of 3 months covering the two prevailing climatic seasons in the country. Both the Akaike and Bayesian information criteria were used in the selection and analysis of ten models to identify the most suitable reaeration coefficient (k2) model for Atuwara River. Models that passed the confidence limit were subjected to model evaluation using measures of agreement between observed and predicted data such as percent bias, Nash–Sutcliffe efficiency, and root mean square observation standard deviation ratio. The used approach yield better results than empirical models developed for local conditions while it is also useful in conserving scarce resources

A Data Mining Process Framework for Churn Management in Mobile Telecommunication Industry

Churning which is a sudden defection of a subscriber to competitors is a disturbing problem in the global telecommunication industry. However, the effectiveness of existing churn control strategies can be improved if an integrated approach that incorporates several dimensions of the phenomenon of churning is adopted. In contrast to existing approaches, this paper proposes an integrated approach to churn management and control by using a data mining process framework that enables churn prediction, determination of reason(s) for churn, and recommendation of appropriate intervention strategy for customer retention. A datamining experiment that was undertaken using data from a major telecom operator in Nigeria to assess the viability of the approach yielded encouraging results

Design, fabrication and testing of shea nut shelling machine

Sheanut (Butyrospernum paradoxum) is an oil rich tropical tree crop, which is indigenous to the West African savannah zone. In Nigeria, most of the sheanuts shelling are done manually by rural women and children, which is labour demanding and tedious. This research work was carried out to determine some physical and mechanical properties of sheanut in order to minimize economic losses associated with its processing. The mean values recorded for the physical properties at 25% moisture content (wb) are; major diameter (29.20 mm), intermediate diameter (21.90 mm), minor diameter (15.00 mm), geometric mean diameter (21.90 mm), arithmetic mean diameter (21.20 mm), angle of repose (30.280). The mean values for the mechanical properties are; linear limit force (0.80 kN), linear limit deformation (4.60 mm), bioyield point force (1.40 kN), bioyield point deformation (6.50 mm), rupture point force (2.10 kN) and rupture point deformation (9.60 mm). Based on the physical and mechanical properties, a sheanut shelling machine was developed that is capable of addressing the aforementioned problems. Putting into consideration better shelling and efficient separation of shea nuts so as to encourage more utilization and processing of shea nuts and its products. The machine was designed to be powered by 5 hp electric motor. It was tested to shell, separate and clean sheanuts. The result of the performance evaluation showed that the machine had shelling efficiency of 96%; cleaning efficiency of the machine was 69.56% while the recovery efficiency was 82.7%. The successful development of this machine will reduce drudgery and time taken associated with the traditional method of sheanut shelling and therefore will increase productivity and utilization