Performance evaluation of an efficient counter-based scheme for mobile ad hoc networks based on realistic mobility model

Flooding is the simplest and commonly used mechanism for broadcasting in mobile ad hoc networks (MANETs). Despite its simplicity, it can result in high redundant retransmission, contention and collision in the network, a phenomenon referred to as broadcast storm problem. Several probabilistic broadcast schemes have been proposed to mitigate this problem inherent with flooding. Recently, we have proposed a hybrid-based scheme as one of the probabilistic scheme, which combines the advantages of pure probabilistic and counter-based schemes to yield a significant performance improvement. Despite these considerable numbers of proposed broadcast schemes, majority of these schemes’ performance evaluation was based on random waypoint model. In this paper, we evaluate the performance of our broadcast scheme using a community based mobility model which is based on social network theory and compare it against widely used random waypoint mobility model. Simulation results have shown that using unrealistic movement pattern does not truly reflect on the actual performance of the scheme in terms of saved-rebroadcast, reachability and end to end delay

A parameter estimation algorithm for induction machines using Artificial Bee Colony (ABC) optimization

Conventionally, parameters of the Induction Motor (IM) are determined using the standard noload and locked rotor test. Performing the no-load test is simple and involved running the machine uncoupled to a load, while measuring the power, voltage, current and shaft speed at different voltage test points. On the other hand, the locked rotor test requires full control of the rotor mechanically in the locked condition before measurements are taken. This paper presents a method for estimating the parameters of IMs without the need for the no-load and locked rotortests. The method is based on optimization approach using a relatively new swarm based algorithm called the Artificial Bee Colony (ABC) optimization. Two different equivalent circuits are implemented for the parameter estimation scheme; one with parallel and the other with series magnetization circuit. Parameters of a standard 7.5kW IM are estimated using the measured and estimated stator current, input and output power and the power factor. Based on the experimental results obtained, the optimization method using the ABC algorithm gave accurate estimates of the IM parameters when compared to the reference parameters determined using the IEEE standard 112-2004. The maximum errors of -13.730% and 2.249% are obtained for the parallel and series equivalent circuits respectively.Keywords: Inductions Machines, Parameter Estimation, Artificial Bee Colony, Magnetization Circuit, Optimization Algorith

Accuracy of self-evaluation in a peer-learning environment: An analysis of a group learning model

There is a global competitive demand for graduates with soft skills, and higher education institutions are tasked to reduce the employee skill gap. Thus, we investigated the students' perceptions of peer assessment in facilitating engagement in soft-skill development through group work activities. Using group work to measure the effectiveness of students' feedback on their assessment, we posit that students perceive self-assessment in group work as a tool that represents fairness. By focusing on learning in a peer-assisted learning environment, the study is a two-period different observation on the effectiveness and validity of peer assessment practice. We applied a group learning model over two academic sessions to investigate if students can self-evaluate accurately in a peer-learning environment. The employed methods included both qualitative and quantitative analysis. The findings of the study differ from previous findings that students cannot self-assess accurately. Empirically, there was no significant difference between the peer marks and tutor marks. The study also found that peer learning improves students' quality of assessment as they reflect on their work better

Seroprevalence of Cytomegalovirus Infection amongst Pregnant Women in Kaduna State, Nigeria

Cytomegalovirus (CMV) is a major public health problem throughout the world. It is the leading cause of congenital infections leading to neurological disabilities in children that result to severe sequelae such as sensor neural hearing loss, neuro-developmental delay and blindness. This study was conducted to determine the seroprevalence of human cytomegalovirus among pregnant women in Kaduna State, Nigeria. Three hundred and sixty three (363) blood samples were collected from 330 pregnant women attending antenatal clinics and 33 non pregnant women attending the Outpatient Department in three selected General Hospitals in Kaduna State. Serum obtained from the blood samples were examinedfor the presence of CMV IgG antibodies by IFA method. About 94.8% of pregnant women tested positive to CMV IgG antibodies while all (100%) of the non pregnant women tested positive. There was no statistically significant association between CMV and pregnancy (÷2=1.784, df=2, p=0.182). Infection with CMV was strongly associated with zone location(÷2=15.381, df,=2, p=0.000) and employment status of the women (÷2=5.519, df=1, p=0.018). There was no significant association between CMV infection and age, gravida, gestation age, education, number of marriages and history of previous transfusion. The high prevalence of CMV infection observed in this study indicates that the virus is prevalent inthe study area and it is therefore advisable that routine screening of CMV infection be implemented for all antenatal women in the State.Keywords: Seroprevalence, Cytomegalovirus, IgG, Pregnant women, Kaduna, Nigeri

Prevalence of Cryptosporidium oocysts among children with acute gastroenteritis in Zaria, Nigeria

This research was conducted to determine the prevalence of Cryptosporidium oocysts among children with acute gastroenteritis in Zaria, Nigeria by Kinyoun Modified Carbol-Fuchsin Staining (Modified Ziehl-Neelsen Staining) Technique. The results for the screening of Cryptosporidium oocysts showed that out of 372 stool samples investigated, 17 samples were positive for the oocysts. Among 17 positive samples, 8 were among 199 male while 9 were among 173 female children studied. The statistical association between microscopic detection of oocyst and gender was not significant (χ2 = 0.297, df = 1, p=0.586). However, there was no statistically significant association between the prevalence of Cryptosporidium oocyst and the age of children observed (χ2 = 7.268, df = 9, p = 0.609). The results also showed no significant association between the prevalence of Cryptosporidium oocysts and the house hold animals (χ2 = 1.489, df = 4, p=0.829). There was also no statistically significant association between the prevalence of Cryptosporidium oocysts and the source of drinking water (χ2 = 6.367, df = 4, p=0.173). Similarly, there was not statistically significant association between the prevalence of Cryptosporidium oocysts and the type of toilet among the study population (χ2 = 1.128, df = 2, p=0.569).Keywords: Children, Cryptosporidium, Gastroenteritis, Oocysts, Prevalence, Zari

Graft copolymerization and characterization of styrene with chitosan via radical polymerization

In this study, styrene was successfully grafted onto chitosan by conventional free radical polymerization technique, using potassium persulphate (KPS) as the initiator. The effect of various reaction conditions including chitosan:monomer weight ratio, polymerization temperature, reaction time and concentration of initiator were studied. The highest percentage grafting (G %) 180% was found at 1:4 chitosan:styrene weight ratio, 0.4 g KPS and 70oC reaction temperature. Fourier transform infrared spectroscopy (FTIR) results showed the presence of polystyrene peaks, indicating the success of the grafting procedure. Thermogravimetric analyses (TGA) revealed that the thermal stability of the prepared copolymer is higher than that of chitosan alone. Mw and Mn of the isolated polystyrene from the graft copolymer were found to be 9.5249 × 104 g/mol and 3.0755 × 104 g/mol, respectively, with a polydispersity index of 3.1Keywords: Biomaterials, Chitosan, Grafting, Polymers, Polystyrene, Potassium persulphat

Seroprevalence of Rubella Specific IgG Antibody among Pregnant Women Attending Ante-Natal Clinics in Kaduna Metropolis, Nigeria

Rubella infection is generally mild in children. However, infection during pregnancy can leads to fetal death or congenital defects known as Congenital Rubella Syndrome. The seroprevalence of IgG to rubella virus was determined using Enzyme Linked Immunosorbent Assay among 400 pregnant women between the ages of 15-45 years attending ante-natal clinics in Kaduna metropolis. Of the 400 samples tested, consisting 20 in their first trimester, 260 in second and 120 in third trimester, 386 (96.5%) were IgG seropositive. Seroprevalence of 95.2% - 100% was obtained across the age groups. In relation to stages of pregnancy 19 (95.0%), 251 (96.5%) and 116 (96.7%) were seropositive in 1st, 2nd and 3rd trimesters respectively. The seroprevalence obtained in this study indicates that majority of the pregnant women had protective antibody due to previous exposure to the virus. However, 3.5% of the pregnant women were susceptible. Therefore, there is a need for government to incorporate rubella vaccine to be part of national immunization programme and screening of women of childbearing age so as to reduce subsequent burden of congenital rubella.Keywords: Rubella, Seroprevalence, Pregnancy, Antibody, ELIS

Sero-prevalence of human parvovirus B19 among patients attending some hospitals in Kano metropolis, Nigeria

Background: Human Parvovirus B19 (HPVB19) belongs to the family Parvoviridae, causes Erythema infectiosum, aplastic crises in persons with blood disorder and prolonged anaemia in immuno-compromised persons. During pregnancy the virus may be transmitted to the foetus which can result in hydrops foetalis, spontaneous abortion or intrauterine foetal death. The study determined the sero-prevalence of IgG antibodies to HPVB19 among patients in Kano metropolis in order to provide information on their immune status and the possible risk factors for acquiring the virus.Method: The study population comprised 460 patients seen at the outpatient department of two hospitals in Kano whose mean age was 28.8 (range 0 –70) years. Questionnaire was used to obtain data on socio-demography and risk factors. Blood sample was collected from each patient, serum was obtained and analysed for IgG antibodies to HPVB19 by ELISA according to manufacturer’s instruction.Result/Discussions: Sero-prevalence of 41.5% (191/460) was obtained for HPVB19 and seropositivity increased significantly with age with the highest prevalence (51%) recorded among patients ≥51 years old while the lowest prevalence was among those < 1 year old (χ2=13.130, df=6, P=0.04). Seropositivity was higher in female (42.6%: 98/230) than male patients (40.4%: 93/230) (p>0.05). Highest seropositivity was observed among farmers (64.2%:18/28) while the lowest was among retired persons (27.2%:3/11). There was significant association between HPVB19 and level of formal education attained (χ2 =10.363, df=4, P=0.03) and number of persons living in a house (χ2 =14.30, df=1, P=0.00). There was no  association between HPVB19 and marital status (P=0.3) and type of residence (P=0.5). Blood transfusion (OR=2.0:1; P=0.08) and sickle cell anaemia (OR=1.7:1; P=0.08) were important risk factors for HPVB19 transmission in this study. Having blood transfusion showed a 2.0 fold risk while having sickle cell showed a 1.7 fold risk of acquiring HPVB19 infection. During the study, 48.2% of women of child bearing age had antibodies to HPVB19 IgG antibodies leaving about 52% still susceptible to the virus.Conclusion: Seroprevalence to B19 among patients was low leaving a large proportion of the population especially women in Kano still susceptible to B19 infection.Keywords: Sero-prevalence, Human Parvovirus B19, Patients, Hospitals, Kano, Nigeri

Study of the Geographically Weighted Regression Application on Climate Data

This study used Geographical Weighted Regression (GWR) technique to find spatial relationship between Elevation and climate (Rainfall, Temperature) in Northern Nigeria using climate (Rainfall, Temperature) data from weather stations from 1980 – 2010 obtained from Nigerian Meteorological Agency (Nimet). From the results of the analysis it was shown that there is significant relationship between the elevation and climate variables (Rainfall, Tmax and Tmin). The study also shows that GWR has smaller residual sum of square than OLS in analysing the relationship between Elevation and Climate data. This may be due to the consideration of the spatial variation of the relationship over the study region. When mapping the results of GWR model it was observed that the effect of Elevation on climate variables appears to vary geographically Keyword: Geographical Weighted Regression (GWR), Ordinary Least square (OLS)