Robust linear classifier for unequal cost ratios of misclassification

This paper focuses on the robust classification procedures when the assumption of equal cost of misclassification is violated. A normal distribution based data set is generated using the Statistical Analysis System (SAS) version 9.1. Using Barlett's approximation to chi-square, the data set was found to be homogenous and was subjected to three linear classifiers namely: Maximum Likelihood Discriminant Function (MLDF), Fisher's linear Discriminant Function and Distance Based Discriminant Function. To Judge the performances of these procedures, the Apparent Error Rates for each procedure is obtained for different cost ratios 1:1, 1:2, 1:3, 1:4 and 1:5 and sample sizes 5:5, 10:10, 20:20, 30:30, and 50:50. The results shows that the three procedures are insensitive to cost ratio exceeding ratio 1:2 and that MLDF was observed as robust discriminant function among classification functions considered

Error Rates Stability of The Homoscedastic Discriminant Function

In this study the stability of the observed error rates of the homoscedastic discriminant function relative to the number of parameters in the model using simulated data from multivariate normal populations was investigated.   Three models were considered, the four, six and eight variables models, each having four values of the separator function (). Equal and unequal prior probabilities were considered for the different number of parameter and separator function configurations. The asymptotic performance of the models was considered using the cross validation error rate estimation procedure. Results indicate the six variable models as being more stable (displaying less variability in the estimated error rates) than the other models under consideration. Less deterioration was observed for the six-variable model specification as was evident in the other models and this was more pronounced for smaller values of. &nbsp

The Impact of Socio-Demographic Factors on Domestic Tourism Consumption Expenditure in Ghana

This study applies quantile regression approach to analyse socio-demographic factors that affect domestic tourism consumption expenditure in Ghana. The approach uses household domestic tourism expenditure as a response variable. The internet access of the household, whether a household owns a mobile phone, and /or at least one car or not are represented as proxies for information and transport accessibility, respectively. Other variables included to constrain household domestic travel budgets are yearly household income and household loan. The rest are demographic characteristics such as age and educational level of household heads. The empirical results show that relatively older and well educated household heads with higher earnings are prepared and willing to expend more on domestic tourism in Ghana. The results further show that, in Ghana, household loans are one of the major constraints of domestic tourism spending for medium and heavy spenders, but positively and significantly influence light domestic tourism expenditure households. Internet access, ownership of a car and mobile phone have no relation with the amount of money spent on domestic tourism in Ghana. Keywords: domestic tourism, quantile regression, tourism consumption expenditure, socio-demographic variables, same-day visitors and overnight tourists. DOI: 10.7176/JTHS/41-05 Publication date:May 31st 201

Degradation of cyclohexane and cyclohexanone by Bacillus lentus strain LP32

A Gram-positive bacterium, Bacillus lentus LP32, originally isolated on the basis of its ability to utilise pyrene as sole source of carbon was found to be able to grow luxuriantly on alicyclic compounds as sole substrates. It showed poor growth on anthracene, naphthalene, 1-naphthol and phenanthrene. Growth rate on cyclohexane was 1.32 d-1, while doubling time was 0.76 d. The corresponding values for growth on cyclohexanone were 0.77 d-1 and 1.29 d, respectively. Within 10 days, the amount of cyclohexane in culture reduced from 317.62 to 102.55 mgl-1, then to 23.04 mgl-1 on day 18. On cyclohexanone, substrate concentration decreased from 287.56 mgl-1 to 101.66 mgl-1 in 10 days before declining to 24.21 mgl-1 on day 18. The rate of degradation when growing on cyclohexane was 23.50 mgl-1d-1 in the first 10 days and 9.93 mgl-1d-1 between day 10 and day 18, with 67.71% degradation in 10 days and overall percentage degradation of 92.43%. On cyclohexanone, the corresponding values were 18.59 and 9.68 mg l-1d-1 as well as 64.65 and 91.58%, respectively. This organism is a potential candidate for bioremediation purpose.Keywords: Degradation, cyclohexane, cyclohexanone, alicyclic compounds

Modelling Domestic Tourism Demand for Ghana

The research analyses the demand for tourism goods and services in Ghana by domestic tourists. For this purpose, it uses the Linear Almost Ideal Demand System (LAIDS) model (static and dynamic) to estimate price and expenditure/income elasticities for the study. The tourism goods and services include: accommodation; food and drinks; transport; recreation, culture and sporting activities; shopping; and other services. The uncompensated and compensated price and expenditure/income elasticities were calculated from the estimated parameters of the LAIDS model, static and dynamic. The results show that all own-price elasticities are negative and significant for uncompensated and compensated elasticities, while expenditure/income elasticities are positive and significant. The findings show that, by short-run, the demand for tourism goods and services in Ghana is price inelastic and expenditure/income elastic, and are normal goods and services. KEY WORDS: Static, dynamic, uncompensated, compensated, AIDS, elasticity. DOI: 10.7176/JTHS/40-0

INDUSTRIAL CLUSTERING AND PERFORMANCE OF TECHNOLOGY-BASED SMES IN NIGERIA: DOES FIRM AGE AND SIZE HAVE ANY INFLUENCE?

This research focused on examining the relationship between industrial clustering and performance of technology-based SMEs in Nigeria, and to identify the moderating role of firm age and size on this relationship. A sample size of 65 owners/managers of technology-based small and medium enterprises were surveyed through the use of structured questionnaire. Hierarchical multiple regression were adopted in analysing the research instrument. Based on the findings from the statistical analysis, this research concludes that there is a direct relationship between industrial clustering and the performance of SMEs in Nigeria. The study also asserts that firm age is a critical influencer of the relationship between industrial clustering and performance of SMEs. Consequently, it is recommended that SME operators in Nigeria should leverage on industrial clustering as a means of enhancing their performance levels. More so, owners/managers of SMEs, bearing in mind the age categorization of their organizations should form industrial clusters in ways that help younger firms share from the experiences of older firms to enhance their performance

Engineering properties of tropical clay and bentonite modified with sawdust

Construction engineers typically avoid the use of expansive soils as construction materials because they are usually difficult to work on and can cause structural failure. This research work investigates how the application of sawdust to tropical clay and bentonite influences their geotechnical properties in order to determine their suitability for use as landfill-liner materials for the effective containment of toxic substances from landfills. X-ray diffractometry, X-ray fluorescence spectroscopy and scanning electron microscopy were used to determine the mineralogical composition, oxide composition and microstructure, respectively, of the clay and the bentonite. A series of laboratory tests were conducted to determine the specific gravity, Atterberg limits, compaction, unconfined compressive strength and permeability characteristics of the clay and the bentonite for varying proportions of sawdust application. Generally, increasing the percentage of sawdust caused a reduction in its specific gravity, maximum dry unit weight and unconfined compressive strength, while it caused an increase in the optimum moisture content and permeability of the modified clay and bentonite. The clay and bentonite both have a sufficiently low permeability that satisfies the hydraulic conductivity requirement for use as clay liners. Eight percent sawdust application to a clay having similar properties as that in this study is recommended as an economic way of modifying it – with the potential of improving its adsorbent property – for use in landfill-liner systems in order to prevent the toxic substances leaching from the landfills, thereby protecting the environment and public health

Incidence of Ascaris infection among primary school children in Ogun State, Nigeria: A generalised linear model approach

To estimate the effect of community soil (location) on the incidence and prevalence of Ascaris infection in school children, the model assumptions of the Generalised Linear Model (GLM) in a linear relationship between independent (Xis) and dependent variable (Y), where (Yi)=i = &#9461Xi1 + &#9462Xi2, + + &#946pXipwas adopted. Of the 1,519 pupils, 30% (225/759) male and 28% (210/760) female pupils were infected with Ascaris lumbricoides but it was not sex-specific (p>0.05). Male pupils voided higher number of worms (1,090, X = 2.2) than female pupils (879, X = 1.7). Intensity of infection rates was inversely related to body weight of pupils. The model observed a significant probability of Keywords: general linear nodel, ascaris, school children, Ogun State, Nigeria.Nigerian Journal of Parasitology Vol. 29 (1) 2008 pp. 32-3

CONSTRUCTING AN INTELLECTUAL PROSPECT OF VENTURE MANAGEMENT PRACTICES: A DIVIDE BETWEEN INFORMAL AND FORMAL ELECTRONICS ENTREPRENEURSHIP

The practice of venture management has recorded success in the United States of America and India. This brought about the turn-around of businesses, both prospect and existing formal business operators in these nations. In the case of Nigeria, banks and other financial institutions have ended up providing advice to successful firms to acquire business organisation in distress and at times are the leaders in that particular industry, thus bringing about unemployment. It is of a note that entrepreneurs are the drivers of a nation’s economy irrespective of government practices. It is based on this premises that the relevance of transition from informal to formal entrepreneurship practices must occur for the existence of economic growth. To bridge this gap in literature, a comparative study on venture management practices and expected performance for practicing entrepreneurs in the informal and formal sector is require

Geochemistry, mineralogy and thermal analyses of Cretaceous coals from the Benue Trough basin Nigeria: Reconnaissance assessments

Selected coal samples from the Benue Trough Basin (Nigeria) were analysed by X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), Fourier transform-infrared spectroscopy (FT-IR), and all the techniques used. The main minerals detected are clays (e.g., kaolinite and illite), quartz, feldspar, hematite and magnetite with traces of calcite, siderite, dolomite, orthoclase and graphite. The authigenic and detrital origins of the clay minerals detected were confirmed by FT-IR analysis. The XPS spectra identified elements similar to the mineral phases observed in the XRD spectra. The contents of Al2O3, CaO, Fe2O3, K2O, Na2O and P2O5 were below the values reported for US and Chinese coals. The elemental indexes (e.g. Al2O3/TiO2, Co/Th vs. La/Sc, Cr/Th vs. Sc/Th) showed that the influence of intermediate-mafic materials derived from source-region sediments is negligible. The Ni/Co ratio showed that the coal forming marsh experienced comparatively mild redox conditions. The ratios of V/(V + Ni), Co/Ni, and Mo/Ni revealed marginal or non-existent marine effects. Trace metals ratios such as V/Ni, Sr/Ba, Rb/Sr, Sr/Cu and V/Zn showed evidence of a large degree of freshwater environment mainly in a humid climate. Maceral composition reflects fluctuations of dry and wet conditions in the forest swamp in a humid environment with an entry of marginal marine system and good plant tissue preservation. The rare earth elements (REE) in the coal samples studied are characterized by light-REE enrichment. Thermal decomposition resulted in the range of residual mass (RM = 33.67%–61.28%) and mass losses (ML = 38.72% - 66.33%), which attributed to the drying, devolatilization, and coke formation. Thermal reactivity followed the sample order A-5 > A-1 > A-6, which indicates A-5 is more thermally reactive. The results indicate that the coal samples could be exploited for electric power generation