REGULARIZATION TECHNIQUES IN MULTIPLE LINEAR REGRESSION IN THE PESENCE OF MULTICOLLINEARITY

Multicollinearity has been a serious problem in regression analysis. Ordinary least square (OLS) regression may result in high variability in the estimates of the regression coefficients in the presence of multicollinearity. Least Absolute Shrinkage and Selection Operator (LASSO), Ridge Regression (RR), and Partial Least Squares (PLS) methods are well established methods that reduce the variability of the estimates by shrinking the coefficients and at the same time produce interpretable models by shrinking some coefficients. The performances of LASSO, Ridge Regression, PLS and OLS estimators were evaluated using Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) in the presence of multicolinearity using Monte Carlo Simulation. The simulations were done for different sample sizes: n (10, 50, 100, 150) and levels of multicollinearity: Mild (0.1 – 0.3), Low (0.4 – 0.6) and High (0.7 - 0.9). OLS had poor parameters estimate and produced wrong inferences, LASSO estimator is the best, while PLS is most efficient when the number of variable is greater than sample size.&nbsp

DEVELOPMENT OF A RECHARGEABLE ELECTRONICALLY CONTROLLED MOTORISED WHEELCHAIR FOR DISABLED AND ELDERLY PEOPLE

The physically challenged, old-age people, and most paralysed patients need means of transportation from place to place to ease their movement. The earlier available wheelchairs are manually driven that need extra effort of either the physically challenged or an assisting person to move. Nowadays, the level of communication and socialization strongly depends on easy access to mobile transportation.  This paper presents a developed motorized wheelchair that facilitates movement of physically challenged people both in the hospital and in their home by taking into account aesthetics, low cost, ease on maintenance with market competitive advantage using locally sourced materials. The developed wheelchair is designed to work for 3 hours under a maximum load of 90 kg with navigation buttons. A working efficiency of 65 % was obtained under full operation. This design brings a new competition into the wheelchair market and gives more comfort to the physically challenged peoples’ mobility than the existing manually driven one

A Comprehensive Performance Evaluation of GGBS-Based Geopolymer Concrete Activated by a Rice Husk Ash-Synthesised Sodium Silicate Solution and Sodium Hydroxide

Commercial sodium hydroxide (NaOH) and sodium silicate (SS) are commonly used as alkaline activators in geopolymer concrete production despite concerns about their availability and associated CO2 emissions. This study employs an alternative alkaline activator (AA) synthesized from a sodium silicate alternative (SSA) solution derived from rice husk ash (RHA) and a 10 M sodium hydroxide solution. The initial phase established an optimal water-to-binder (W/B) ratio of 0.50, balancing workability and structural performance. Subsequent investigations explored the influence of the alkali/precursor (A/P) ratio on geopolymer concrete properties. A control mix uses ordinary Portland cement (OPC), while ground granulated blast-furnace slag (GGBS)-based geopolymer concrete—GPC mixes (GPC1, GPC2, GPC3, GPC4) vary the A/P ratios (0.2, 0.4, 0.6, 0.8) with a 1:1 ratio of sodium silicate to sodium hydroxide (SS: SH). The engineering performance was evaluated through a slump test, and unconfined compressive strength (UCS) and tensile splitting (TS) tests in accordance with the appropriate standards. The geopolymer mixes, excluding GPC3, offer suitable workability; UCS and TS, though lower than the control mix, peak at an A/P ratio of 0.4. Despite lower mechanical strength than OPC, geopolymers’ environmental benefits make them a valuable alternative. GPC2, with a 0.4 A/P ratio and 0.5 W/B (water to binder) ratio, is recommended for balanced workability and structural performance. Future research should focus on enhancing the mechanical properties of geopolymer concrete for sustainable, high-performance mixtures

Web-Based Advanced Traveller Information System for Minna Metropolis, Nigeria

Advanced Traveller Information System (ATIS) is used to provide accurate, integrated and comprehensive travel and traffic information to road users. The information helps in both pre-trip and en-route decision making. This study developed a web-based ATIS for Minna metropolis in Nigeria. The information provided is from both primary and secondary sources. The developed ATIS provides information on route guidance, available intercity transport services and hotels in the metropolis. It also allows users to determine both weather and traffic flow conditions. A component of the system makes provision for electronic fare payment and booking of trips and hotel accommodation. The deployment of the ATIS is a source of static and dynamic information

The Gamma-Rayleigh Distribution and Applications to Survival Data

Studies on probability distribution functions and their properties are needful as they are very important in modeling random phenomena. However, research has shown that some real life data can be modeled more adequately by distributions obtained as combination of two random variables with known probability distributions. This paper introduces the Gamma-Rayleigh distribution (GRD) as a new member of the Gamma-X family of generalized distributions. The Transformed-Transformer method is used to combine the Gamma and Rayleigh distributions. Various properties of the resulting twoparameter Gamma-Rayleigh distribution, including moments, moment generating function, survival function and hazard function are derived. Results of simulation study reveals that the distribution is unimodal, skewed and normal-type for some values of the shape parameter. The distribution is also found to relate with the Gamma, Rayleigh and Generalized-Gamma distributions. The method of maximum likelihood has been used to estimate the shape and scale parameters of the distribution. To illustrate its adequacy in modelling real life data the distribution is fitted to two survival data sets. The results show that the distribution produced fits that are competitive and compared better, in some cases, to the Gamma, Rayleigh, Weibull and Lognormal distributions.Keywords: Gamma-X family, Gamma-Rayleigh distribution, Maximum Likelihood estimators, Survival data

Impact Of Covid-19 Pandemic Lockdown on Social and Mental Health of ondo State Residents, Nigeria

COVID-19 is a pandemic disease which has caused fears and concerns among many people, with a significant influence on social and mental well-being. Considering this, this study investigated the impact of COVID-19 pandemic lockdown on social and mental health of Ondo State residents, Nigeria. Descriptive survey design was used in this study. Using multistage sampling technique, data were obtained through administration of questionnaire on 648 married couples with children in Ondo State. Data collected were analysed using inferential statistics. Findings revealed that respondents disclosed that their income and earnings have drastically reduced (X̄ = 2.89), feel withdrawn from community participation (X̄ = 2.96), reduced their interaction with people (X̄ = 2.98), reduced their interaction with their loved ones (X̄ = 2.67). The impact of COVID-19 lockdown on the mental health of the residents indicated that majority of the respondents feel lonely due to COVID-19 lockdown (X̄ = 3.00), feel distressed (X̄ = 2.87) and agitated (X̄ = of 2.47). The study revealed a significant difference in the social and mental health of Ondo state residents based on their age and gender; F (5, 642) = 10.554, p<.05, ɳ2 =.076; F (5, 642) = 6.694, p<.05, ɳ2 =.000 respectively. Hence, the impacts of the COVID-19 lockdown on the social and mental health of majority of the respondents was obvious. Therefore, health education awareness raising activities on mass media should be urgently conducted with focus on how people can cope effectively with their social and mental health during this lockdown period. &nbsp

Determinants of Depression among University Students in Nigeria

الملخص: تبحث الدراسة محددات الاكتئاب بين طلاب الجامعات في نيجيريا، وقد اُستخدم المنهج الوصفي من خلال تطبيق استبيان في هذه الدراسة. شملت عيّنة الدراسة جميع طلاب الجامعات في نيجيريا، وتكونت عينة الدراسة من 1050 طالبًا جامعيًا. قام الباحثون بإعداد استبانة خاصة للدراسة، باستخدام نمط الاستجابات المغلقة. أظهرت النتائج أن العمر والدخل عوامل مهمة في مستوى الاكتئاب لدى طلاب الجامعات في نيجيريا، بينما نوع الأسرة لم يكن له تأثير، وعليه فقد جاءت التوصيات على أنه يجب على إدارة الجامعة تحسين خدمات الصحة العقلية من خلال زيادة التثقيف الصحي للكشف المبكر والسيطرة على حالات الاكتئاب بين الطلاب.Abstract: The study examined the determinants of depression among university students in Nigeria. Additionally, descriptive research design of survey type was used in this study. The population for this study comprised of all Nigeria undergraduate students. The sample for the study was 1,050 undergraduates. The instrument used for this study was a self-constructed, structured close ended questionnaire. Findings revealed that age and income were significant determinants of depression among university students in Nigeria while family type is not. It was therefore recommended that the University management should strengthen mental health services through health education to enable early detection and management of depression among students

MODELING THE AIR FLOW RESISTANCE OF BULK SPONGE GOURD (LUFFA CYLINDRICA) SEEDS

The knowledge of airflow resistant of agricultural materials is important to the design of drying and aeration systems and enhances proper fan selection for these systems. This study investigated the pressure drop across a bed of sponge gourd (Luffa cylindrica) seeds at moisture contents in the range of 9.98 to 16.5% (w.b), airflow rate of 0.11 to 0.32 m3s-1m-2, material bed depth (0.2 to 0.8 m) and bulk density (loose, medium, and high). Pressure drop data was fitted to three common airflow resistance models (Shedd’s, Hukill and Ives’s, and Ergun’s models). An empirical equation comprised bulk density, moisture content, and airflow rate was also developed to predict the pressure drop of sponge gourd seeds. Results obtained indicated that the airflow resistance of sponge gourd seeds increased with increase in airflow rate, bed depth but decreased with moisture content. Increased bulk density resulting from loose to densely filled resulted in an increase in resistance to airflow. Shedd model was selected to be the best for predicting pressure drop across bulk sponge gourd seeds for all the condition studied due to its high value for Coefficient of Determination (R2) of 0.996 and a low root mean square error value (0.0279) compared to other models. The empirical equation developed predicted well the pressure drop with R2 and RMSE values of 0.950 and 0.264 respectively

DRYING CHARACTERISTICS OF KEREWA TOMATO UNDER INFRARED DRYING

 In Drying characteristic for infrared drying of tomato slices were investigated. The drying experiments were carried out using Kerewa local varieties of tomato at five infrared drying power (150, 250, 300, 400 and 500 W) with slice thickness of 10 mm. For all drying powers there was a reduction in moisture content with increased drying time, the drying took place in the falling rate period. The drying time reduced as the infrared heating power increased from 150 to 500W. The diffusivity obtained for the tomato slices were within the range specified for fruits and vegetables with a value of 5.6132 x 10-7 m/s2.  Blanched tomato varieties had better rehydration capacities than all unblanched samples