Energy-Efficiency of Cooperative MIMO Wireless Systems

Increasing focus on global warming has challenged the scientific community to develop ways to mitigate its adverse effects. This is more so important as different technologies become an integral part of daily human life. Mobile wireless networks and mobile devices form a significant part of these technologies. It is estimated that there are over four billion mobile phone subscribers worldwide and this number is still growing as more people get connected in developing countries [1]. In addition to the growing number of subscribers, there is an explosive growth in high data applications among mobile terminal users. This has put increased demand on the mobile network in terms of energy needed to support both the growth in subscribers and higher data rates. The mobile wireless industry therefore has a significant part to play in the mitigation of global warming effects. To achieve this goal, there is a need to develop and design energy efficient communication schemes for deployment in future networks and upgrades to existing networks. This is not only done in the wireless communication infrastructure but also in mobile terminals. In this thesis a practical power consumption model which includes circuit power consumption from the different components in a transceiver chain is analyzed. This is of great significance to practical system design when doing energy consumption and energy efficiency analysis. The proposed power consumption model is then used to evaluate the energy efficiency in the context of cooperative Multiple Input Multiple Output (MIMO) systems

Availability and Adequacy of Physical Infrastructure as Determinants of Parental Choice of Primary Schools in Embakasi Sub-County, Nairobi City County, Kenya

The purpose of the study was to investigate the influence of physical facilities on parental choice of primary schools in Embakasi Sub-county, Nairobi City County, Kenya. Specifically, the study sought to determine the extent to which the adequacy and condition of physical facilities influenced parents’ choice of primary schools. The study also sought to compare the adequacy and condition of physical facilities in public and private schools in Embakasi Sub-county. Using a descriptive survey design, the study targeted 20 public schools with 30,201 parents and 97 private schools with 30,257 parents.  To pick the study sample, the population was stratified into two subgroups of public and private schools. Each of the subgroups was further subdivided into subgroups of school heads and parents from which 95 school heads and 600 parents were picked.  Systematic sampling was used to pick the respondents. Primary data were collected using questionnaires. Collected data was analyzed qualitatively based on themes and quantitatively using frequencies and percentages. The study findings revealed that majority (68.7%) of the parents were influenced by availability of permanent buildings. Well-stocked libraries ranked second at 54.4 percent while good furniture ranked third at 39.5 percent. The study recommends that the Ministry of Education, Science and Technology (MoEST) in partnership with other stakeholders ensures that schools have adequate facilities to meet parents’ expectations. There is also need for regular assessment of both public and private schools by MoEST to ensure that they operate above a given minimum standard of physical facilities. Keywords: Physical facilities, Parental choice, availability, adequacy (247 words

A Preliminary Yield Model for Natural Yushania Alpina Bamboo in Kenya

Natural bamboo resources in Kenya are about 150,000 ha and they are mainly found on the mountain slopes in the high potential areas in Mt Kenya, Aberdares ranges, Mau escarpment, Cherangani hills and Mt Elgon at high elevations between 2300 and 3200 meters above sea level.  There is only one indigenous bamboo species, Yushania alpina (formerly Arundinaria alpina). It grows in single culms grouped into clumps. The main use of Y. alpina bamboo in Kenya is construction and fencing. There is high demand for bamboo for use in horticulture farming, handcraft, residential fencing, and cottage industry for making furniture, baskets, tooth picks and match sticks. Some companies have expressed interest in using large amounts of bamboo for bio-energy, panels, particle boards and pulp. However, bamboo raw material is not available for use because of a Presidential ban imposed on harvesting bamboo resources in all Government and Trust lands. But even if the ban was lifted, harvesting of bamboo in the natural forests cannot be prudent because there is very little information on the quantity, quality and geographical distribution of the available amount. Many entrepreneurs have continued to request the Government through Kenya Forest Service (KFS) to be allowed to extract natural bamboo for various uses. On the other front Kenya Forestry Research Institute (KEFRI) has vigorously continued to promote growing and intensive use of bamboo. These two noble ideas cannot be realized in the absence of the bamboo resource data. The objective of this study was to develop a yield model that can be used to estimate total bamboo culms biomass in a given area and the proportion that can be harvested on a sustainable basis. This study used bamboo data from 25 rectangular temporary sample plots of 10 m x 20 m in natural stands of Y. alpina and trees at Kieni, Kamae and Kinale in Kiambu County to estimate density and model the dependence of culms merchantable green weight and oven dry weight on diameter at breast height. The culms mean stoking density was 21000 culms ha-1. The coefficient of determination (R2) for green weight model is 0.82 and the root mean square error (RMSE) is 1.45 kg. The model calculates mean weight of old Y. alpina culm as 9.6 kg. Keywords: Bamboo, stocking, yield, weight, culms, green weight mode

Development of smart controller model for dual fuel generator systems

Application of dual fuel powered electric generators such as one of diesel and biogas has gained popularity locally both as emergency power supply units and in distributed power systems. Dual fuel generators use two fuel types simultaneously in their operations. This is however faced with challenges in control and fuel regulation since their operation must be economically feasible and convenient. To achieve this, an intelligent controller that regulates generator operations is necessary. This research work, set to determine operation characteristic of these generators and fuel‐load relationship of the dual fuel engines in order to design a control system for a dual fuel power generator system. Generator characteristics such as fuel consumption on various loads were obtained through experiments; it was found that injection of biogas in diesel engine saves diesel consumption by approximately 30% on low load and 60% on high load. The presented model switches the generator when needed and adjusts biogas inlet in steps proportional to the load. It works by monitoring load, injecting a small volume of biogas for loads below 10% and increasing it as the load increases to maximum possible volume for load above 80%. The model was tested through simulation of the obtained data on a Siemens ™ micro Logic controller demonstrating a solution to control challenges. This model logic for control and offers advanced logic electronic control for local applications. It is essential in providing a versatile solution for a middle sized diesel biogas dual fuel power generator control

ACADEMIC SELF-EFFICACY, ATTITUDES AND KNOWLEDGE AMONG UNDERGRADUATE BIOSTATISTICS STUDENTS

Objective: The objectives of the present study were to evaluate the academic self-efficacy, content knowledge and confidence in these responses, as well as attitudes of students in an undergraduate biostatistics course. Design: The study was a cross-sectional analytical design. Setting: The study was carried out in Masinde Muliro University of science and technology Sample: Sampling frame consisting of 114 students who had at least taken a biostatistics course. Probability sampling technique of purposive sampling method was applied to select the students. (n = 114) Analysis: Data were analyzed through path analysis and confirmatory factor analysis. Main measures: Self-efficacy, confidence, attitude and knowledge Results: The estimation of this hypothesized structural model yielded an acceptable fit to the data, χ2 =45.9, df = 2; χ2/df ratio =22.123 (good), CFI = .933; RMSEA = .071, with 90% C.I. = .044 - .083, SRMR = .078. Attitude was a direct predictor of self-efficacy (β = .490, p < .001), confidence was a direct predictor of self-efficacy (β = .400, p < .001), self-efficacy was a direct predictor of knowledge (β = .515, p < .001). Conclusion: The study concludes that academic self-efficacy and optimism were strongly related to performance. Therefore, this study supports previous literature that found academic self-efficacy affects the success of students in the sciences. Recommendation: Educators should be aware of students' personality antecedents in order to improve their students' beliefs about their capabilities to master different areas of coursework.  Article visualizations

COMPARATIVE STUDY OF ANTHROPOMETRICS, BLOOD PRESSURE PHENOTYPES AND BIOMOTOR VARIABLES AMONG SPORTS AND NON-SPORTS UNIVERSITY STUDENTS

The aim of this investigation was to compare anthropometric, blood pressure phenotypes and bio-motor variables between sports and non-sports university students aged 21.4 ± 2.1 years (mean ± s) and also to study the discriminating power of selected anthropometric and bio-motor variables among university students in the two groups (sports n=119 and non-sports n=166) in Kenya. A cross-Sectional analytical study design was used in the study. University students randomly selected in both groups (n = 285) volunteered as subjects. Anthropometric parameters assessed included body mass, height, and body fat percentage. The bio-motor variables assessed included upper body endurance and abdominal endurance. Blood pressure phenotypes assessed included pulse rate and mean arterial blood pressure which was computed from systolic and diastolic blood pressures. Multivariate analysis of covariance (MANCOVA) and Linear discriminant analysis (LDA) were used for analysis in Statistical packages for social science version 25. The results showed that the non-sports group had a numerically high BMI and body fat percentage (23.4; 22.2) compared to the sports group (19.8; 17.5). With regards to blood pressure, the mean arterial blood pressure and pulse rate of the non-sports group was high (87.9; 83.3) compared to the sports group (85.9; 75.2). The multivariate test of differences in groups as a result of the linear combination of all predictor variables showed that the mean vectors for the two groups were significant for groups (Pillai’s T, P<0.01) but not for the covariate Age (Pillai’s T, P=.149). Results for the individual test of differences in adjusted means (marginal means) showed that there were statistically significant differences adjusted for age between the sports and non-sports groups in all dependent variables(p<0.05) except Mean arterial blood pressure (f (2,282) =.988, p=.321). Results from the LDA yielded only one significant function and all six variables significantly contributed to the discriminant analysis (Wilks A = 0.639, x2 = 125.34, df=6, p < 0.01, R2 = .36). The structure coefficients of all variables were greater than 0.25. The original classification summary showed that 81.8% of the cases were correctly classified in their respective group. In conclusion, the anthropometric, bio-motor and blood pressure phenotypes of sports students were significantly different from non-sports students. The study recommended that well-planned programs of physical and mental health should be initiated in all educational institutes.  Article visualizations

ASSESSMENT OF PRE-SEASON ANTHROPOMETRIC TESTS OF RUGBY PLAYERS IN A CHAMPIONSHIP CLUB, KENYAN RUGBY UNION

Objective: The objectives of the present study were to evaluate the anthropometric factors of rugby players on preseason before the onset of the training in a championship club (Kisumu Rugby Rfc Setting: The study was carried out in a Kenya at a Kenya rugby union (Kisumu Rfc) championship club. Sample: Sampling frame consisting of 52 players who were registered in the club at the time of the study. (n =52) Analysis: Data were analyzed through descriptive and inferential statistics, linear and multiple regression analyses. Main measures: Maximal Aerobic power, demographics and strength tests of back squat and Bench press. Results: The estimation of this hypothesized factors that affect maximal aerobic power were age, Primary position, weight, injury F (7,44) =.622, P<.735, R2=. There was correlation between several factors that affect maximal aerobic factors with the linear regression formula generated being Maximal Aerobic Power (VO2Max) = 12.12 + (0.49xAge) - (017xWeight) – (0.657xPosition) + (257X FMSTM (z-score) – (0.52x100m) + (.170xPlanks) + (0.37xPush-ups) Conclusion: aerobic power (VO2Max) is influenced by several factors including age of the rugby players, weight of the players and the playing positions of the players. Recommendation: Future research should further clarify how preseason testing and anthropometric tests of rugby players would influence the outcome on fitness before the start of the season which the ultimate goal of most rugby players and coaches.  Article visualizations

Pit latrine faecal sludge accumulation: assessment of trends and determinants in low-income settlements, Nakuru, Kenya

Sustainable pit latrine services face numerous challenges despite their sanitation role in non-sewerage connected settlements. This study was carried in 5 low income settlements in Nakuru, Kenya. Its objectives were to assess pit latrine user management and sludge accumulation rates. 100 households were surveyed and fill-up in 73 pit latrines monitored. Operational period average was 15 years, 23 people shared a pit latrine, 61% of the facilities had solid waste disposal and 45% of the respondents had no sanitation awareness. Sludge accumulation ranged from -0.98 to 10.32 m3, fill up rate was 0.87±0.20 m3 per year and individual contribution was 41.82 liters annually. The sludge accumulation rates across the study areas had statistically significant mean difference (Fishers Exact Test, p<0.05). The relationship between user activities, operational management and design affect performance. Hence linking the variables would scale up outcomes. Key words: Faecal sludge, shared sanitation, latrine fill-up, basic sanitation

Impact of Land Use on Water Quality in River Njoro Watershed, Kenya

Water resources within the River Njoro watershed have become degraded due to high population growth rate and change in land use upsetting environmental stability. Land cover classification using Landsat images (Baldyga et al., 2004) shows loss of about 20% of forested areas between 1986 and 2003 in the watershed. The forested and large-scale farm areas have been converted mainly into small-scale mixed agriculture and human settlements. These changes have impacted negatively on the ecological integrity and hydrologic processes in the watershed (Shivoga, 2001) but little is known about the influence of specific land uses on water quality of the river