Derivations and Centroids of Four Dimensional Associative Algebras

In this paper, we focus on derivations and centroids of four dimensional associative algebras. Using an existing classification result of low dimensional associative algebras, we describe the derivations and centroids of four dimensional associative algebras. We also identify algebra(s) that belong to the characteristically nilpotent class among the algebras of four dimensional associative algebras.Comment: 20 pages, 2 tables, Accepted in International Journal of Pure and Applied Mathematic

Deterministic Model for Noise Dispersion from Gas Flaring: A Case Study of Niger – Delta Area of Nigeria

Noise is an audible acoustic energy that adversely affects the health, physiological and psychological well being of the individuals or populations. One of the major pollutants from gas flaring is the noise emanating from gas flaring stations in the Niger – Delta area of Nigeria. Noise dispersion produces many adverse effects on man and animals. Experimental analysis of noise dispersion and weather conditions used for simulation has been carried out, the modeling and simulation of noise dispersion from flare stations using visual basic programme is the main focus of this work. Results obtained shows some variation between the simulated results and experimental results, with correlation coefficient ranging from 0.955 – 0.995. Simulation results of the developed model show that the noise intensity level reduces with increasing in distance from the flare point and that weather conditions has an important influence on noise dispersion

Empirical analysis of rough set categorical clustering techniques based on rough purity and value set

Clustering a set of objects into homogeneous groups is a fundamental operation in data mining. Recently, attention has been put on categorical data clustering, where data objects are made up of non-numerical attributes. The implementation of several existing categorical clustering techniques is challenging as some are unable to handle uncertainty and others have stability issues. In the process of dealing with categorical data and handling uncertainty, the rough set theory has become well-established mechanism in a wide variety of applications including databases. The recent techniques such as Information-Theoretic Dependency Roughness (ITDR), Maximum Dependency Attribute (MDA) and Maximum Significance Attribute (MSA) outperformed their predecessor approaches like Bi-Clustering (BC), Total Roughness (TR), Min-Min Roughness (MMR), and standard-deviation roughness (SDR). This work explores the limitations and issues of ITDR, MDA and MSA techniques on data sets where these techniques fails to select or faces difficulty in selecting their best clustering attribute. Accordingly, two alternative techniques named Rough Purity Approach (RPA) and Maximum Value Attribute (MVA) are proposed. The novelty of both proposed approaches is that, the RPA presents a new uncertainty definition based on purity of rough relational data base whereas, the MVA unlike other rough set theory techniques uses the domain knowledge such as value set combined with number of clusters (NoC). To show the significance, mathematical and theoretical basis for proposed approaches, several propositions are illustrated. Moreover, the recent rough categorical techniques like MDA, MSA, ITDR and classical clustering technique like simple K-mean are used for comparison and the results are presented in tabular and graphical forms. For experiments, data sets from previously utilized research cases, a real supply base management (SBM) data set and UCI repository are utilized. The results reveal significant improvement by proposed techniques for categorical clustering in terms of purity (21%), entropy (9%), accuracy (16%), rough accuracy (11%), iterations (99%) and time (93%). vi

Aperture-Coupled Asymmetric Dielectric Resonators Antenna for Wideband Applications

yesA compact dielectric resonator antenna (DRA) for wideband applications is proposed. Two cylindrical dielectric resonators which are asymmetrically located with respect to the center of a rectangular coupling aperture are fed through this aperture. By optimizing the design parameters, an impedance bandwidth of about 29%, covering the frequency range from 9.62 GHz to 12.9 GHz, and a gain of 8 dBi are obtained. Design details of the proposed antenna and the results of both simulation and experiment are presented and discussed