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Critical leader behaviour in the emerging South African economy by Rossouw, Gedeon Josua
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Developments in anaerobic digestion modelling by Ghoor, Tasneem
Published 2020“…Due to the complexity of the physical, biological and aqueous interactions, many model simulations were needed to identify the important parameters with the lasso (least absolute shrinkage and selection operator) feature selection method. …”
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Water demand of selected residential properties with access to groundwater in serviced areas of the Cape Peninsula by Wright, Tiaan
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Page will reload when a filter is selected or excluded.- "This investigation derived its strong motivation in the adoption of versions of second-order Runge-Kutta methods where there is presently dearth of relevant literature to re-establish .the complicated nature of solution of buffing oscillator dynamics. The choice of second-order Runge-Kutta methods hinged On its simplest algebraic formulation of relevant coefficients based on Taylor series expansion comparing with its higher order counterpart. Validation of FORTRAN-90 codes of algorithms was achieved by phase plots comparison reference to Dowell (1988) as standard. The nature of simulated solutions were visually determined with scatter plot of phase variables obtained from simultaneous implementation of large number of versions of second-order Runge-Kutta methods in conjunction with the corresponding literature results. Validation results are acceptable to within the accuracy limit of Runge-Kutta methods adopted. The scatter plots on phase plane for cases investigated are well structured and bounded (strange) and compare correspondingly well with literature Poincare sections. This investigation re-establishes the complex nature of solution of Duffings oscillator dynamics. Its established procedures provide an alternative Poincare section method and can be utilised for preliminary verification of system dynamics behaviour subject to confirmation by additional dynamics tests. " 1 results 1
- "This study investigated the characterisation of the dynamic responses of 3-dimensional Lorenz and Rӧsler models by Lyapunov's exponents using popular but laborious to implement Grahm Schmidt orthogonal rules over wider range of models driven parameters. The study also verifies a new proposed model for the validation of Lyapunov's spectrum when the requisite matrix depends on positions on the model attractor. Models and the corresponding Lyapunov's spectrums were simulated by appropriately effecting Grahm Schmidt orthogonal rules and using three different detailed constant step Runge-Kutta algorithms. The FORTRAN-90 coded algorithms were validated using literature results reported by Vladimir Golovko (2003). The stability of Lyapunov's exponents estimate variation was studied in the range of estimate reset period of 2≤τ≤16 .The Lorenz model was characterized at δ = 10, ƿ =28, and 1≤β≤2.8. This range covers both square and rectangular geometries. Similarly, Rӧsler model was characterised at a=ᵞ=0.2 and 2≤µ≤6. This range has potential to drive the model both periodically and chaotically depending on the choices of µ .The validation of the largest Lyapunov's exponents (λ)in Rosier model suffered the highest relative absolute percentage error of 14.29 while its absolute error is one of the lowest (0.01). The remaining five Lyapunov's exponents (three from Lorenz and two < from Rӧsier) suffered relative absolute percentage error of ≤ 2.00. Estimated Lyapunov's exponents stabilise for estimate reset period ≤ 10 .The most stable algorithms was found to be Butcher's modified fifth order followed respectively by fourth (RK4) and fifth (RK5) order. Estimation of Lyapunov's exponents' in Rӧsier model was found to be insensitive to algorithms due to its relative low degree of nonlinearity when compared with Lorenz model. It was established that the sum of Lyapunov's spectrum is the same as the average of trace of variation square matrix over large iteration regardless of dependence on position variable or not. This study demonstrated that the utility of Lyapunov's exponents as response characterising tool of dynamic systems driven by different parameters combination justify its laborious estimation by Grahm Schmidt method. " 1 results 1
- "This study utilised positive Lyapunov exponents' criteria to develop chaos diagram on the parameters space of 4-dimensionalharmonically excited vibration absorber control Duffing's Oscillator. Relevant simulations were effected by choice combination of constant step Runge-Kutta methods and Grahm Schmidt Orthogonal rules. Simulations of 4-dimensional hyper-chaotic models of modified Lorenz and RÖsier were used for validation purposes. Lyapunov's spectrums were obtained at (197 x 301) mesh points of parameters space (µ,αa). Lyapunov's spectrum of modified Lorenz system by constant time step (NRK1) fourth order Runge-Kutta method (04208.01650. - 0.0807, -26.4603) compare correspondingly well with (0.4254, 0.1286, 0.0000, -26.5493) reported by Yuxia et et. Similarly, Lyapunovs spectrum of modified Rosier system by constant time step (NRK1) fourth order Runge-Kutta method (0.1424, 0.0051, -0.0041, -24.0831) compare correspondingly and qualitatively with (0.1287, 0.0149, -0.0056, -22.8617) reported by Marco (1996). The sum of Lyapunov exponents (-22.7237, -31.3107, -27.8797) in Rosier compare correspondingly and qualitatively with variation matrix measure -AVERT (- 24.0181, -30.9462, -28.1991) respectively for fourth, fifth and modified fifth order Runge-Kutta methods. The chaos diagram results suggested preferentially higher mass ratio for effective chaos control of Duffing's Oscillator main mass. The parameters space in the region of relative lower mass ratio suffered irregular boundaries. The practical applications of this chaos diagram plot include, by instance, walking in the parameters-space of vibration absorber control Duffing's Oscillator along suitable engineering paths. " 1 results 1
- Abelmoschus Esculentus. 1 results 1
- Academic journals are an important outlet for dissemination of academic research. In this study, Neural Networks model was used in the prediction of abstracts from The Institute of Electrical and Electronics Engineers (IEEE) Transactions on Computers. Simulation of results was done using the Polynomial Neural Networks algorithm. This algorithm, which is based on Group Method of Data Handling (GMDH) method, utilizes a class of polynomials such as linear, quadratic and modified quadratic. The prediction was done for a period of twenty-four months using a predictive model of three layers and two coefficients. The performance measures used in this study were mean square errors, mean absolute error and root mean square error. 1 results 1
- African Heritage Research Library Nigeria 1 results 1
- Background: Rape is the most common form of violence in conflict and refugee situations but because of the associated stigma few cases are reported. This study assessed the outcome of an intervention targeted at women groups on the utilization of medical services by rape survivors in refugee camps in Zambia. Methods: A prospective quasi-experimental community-based intervention study was carried out in two refugee camps allocated into intervention and comparison areas. The intervention was participatory education sessions for women groups. Data was collected using the clinic records and the main outcome was the number of rape survivors who utilized and completed medical services provided at the camp clinics. Univariate, bivariate and multivariate analyses were carried out with level of significance set at 5%. Results: The proportion of the rape survivors who accessed medical care within 72 hours increased significantly from 41.2% to 84.8% in the intervention area but from 31.1% to 38.9% in the comparison area, (p=0.005). Those who completed their medical treatment and the follow-up visits increased significantly from 42.8% to 94.8% in intervention area but reduced from 38.5% to 21.4% in the comparison area, (p=0.002). Being resident in the intervention area predicted the utilization of medical services, [OR: 3.15; 95%CI: 1.955-5.681], p=0.002. Conclusion: Community-based intervention using participatory women’s group discussion had a significant impact on increasing the utilization of medical services by rape survivors and should be considered for scaling up as a key intervention for increasing utilization of medical services for rape survivors especially in refugee situations. 1 results 1
- Climatic parameters 1 results 1
- Conflict resolution 1 results 1
- Embedded mobile agent 1 results 1
- Empirical models 1 results 1
- Ethnic hatred 1 results 1
- GMDH 1 results 1
- Genocide 1 results 1
- HIV 1 results 1
- Heavy Metals 1 results 1
- IEEE 1 results 1
- INTRODUCTION: Mother-to-child transmission is the major route of pediatric Human Immunodeficiency Virus (HIV) infection accounting for 90% of childhood HIV infection. Poor utilization of prevention of mother-to-child transmission (PMTCT) of HIV services has been shown in this situation. Hence, the study assessed the perception and utilization of PMTCT services among Women Living with HIV (WLHIV). METHODS: A cross-sectional research design was used with a purposive sampling technique to select 182 WLHIV within reproductive age attending President’s Emergency Plan for Acquired Immunodeficiency Syndrome (AIDS) Relief (PEPFAR)/AIDS Prevention Initiative in Nigeria (APIN) clinic in two secondary Health facilities in Ibadan, Oyo State. A validated structured questionnaire was used for data collection. Descriptive and inferential statistics were used for data analysis. RESULTS: The mean age of the women was 37.0±6.5 years. Majority (74.2%) of the respondents had good knowledge on PMTCT of HIV, positive perception (89%) towards PMTCT services while only 42.9% of the respondents have utilized PMTCT services during pregnancy. However, some of the challenges to use of PMTCT services identified by the respondents were stigma (16.5%), discrimination (15.4%), financial constraint (11.5%) and non-involvement of partner (8.2%). There was a significant association between level of knowledge and PMTCT services utilization (χ2=6.244, p=0.012). CONCLUSIONS: There is need for improvement of knowledge and perception of HIV, MTCT and PMTCT among women through counseling and antenatal education, thereby increasing PMTCT services uptake. Partner involvement, good quality PMTCT services and lack of discrimination of people living with HIV in our society should be encouraged, hence promoting the utilization of PMTCT services. 1 results 1
- In the region where solar radiation data are scarce, the next alternative method is to use solar radiation models to estimate the data needed for some applications such as simulation of crop performance and the design of solar energy conversion devices. In this paper, the validations of fifteen models for estimating monthly mean daily global solar radiation on the horizontal surfaces were conducted at a location in salielian region where there is great potential for solar energy utilization in electricity generation and irrigation. Evaluations of these models were carried out by using the Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE) and t-test. Three of these statistical performance indicators were combined to generate rank score for each model. Temperature based models made the rank of the best three during the wet season. On the annual scale and in the dry season, temperature variations and humidity were combined with sunshine duration to get the best rank of I to 3. 1 results 1
- Infant nurturing 1 results 1
- Java agent development framework. 1 results 1
- Lagos 1 results 1
- Library services 1 results 1
- Mean absolute error 1 results 1
- Mean square errors 1 results 1
- Medical services 1 results 1
- Mobile Agent Technology (MAT), remote method invocation and remote procedure calling are the three most widely used techniques for information storage and retrieval in network environments. Previous studies have shown that MAT provides a more efficient and dynamic approach to information storage and retrieval than others. However, for mobile agents to effectively perform their various tasks, a static agent platform must be installed on the computers. These platforms consume more memory, increase access time and prevent other tasks from running on the computer. Therefore, an alternative framework that will eliminate the problems associated with agent platform is imperative. Consequently, this work was aimed at developing a more efficient framework for mobile agent system deployment as an operating system service. Two classes of existing information retrieval agents were adapted to develop Embedded Mobile Agent (EMA) system. The EMA was embedded into the Windows Operating System (OS) kernel, so that it could run as a service for information retrieval. This was done to eliminate the overheads associated with the middleware provided by agent platforms. The targeted OS were Windows XP, Windows Vista and Windows7. Mathematical models were simulated to assess the performance of EMA by measuring service delay, memory utilisation, fault tolerance, turn around time at fixed bandwidth with varying number of network nodes, and percentage denial of service. Denied services were generated by a random number generator modelled after the Bernoulli Random Variable with 0.1 probability of failure. The model‟s performance was then compared with Java Agent DEvelopment framework (JADE), a widely used open-source existing mobile agent system running on platforms. The implementation was done using four computer systems running the targeted Windows on an existing local area network. Analysis of data was done using descriptive statistics and independent t-test at p = 0.01. The EMA model effectively retrieved information from the network without the agent platform, thereby reducing access times and saving memory, regardless of the version of the Windows OS. The mean service delay for EMA (15067.5 ± 8489.6 ms) was lower than that of JADE (15697.0 ± 8844.5 ms). The embedded agent requires 3 KB of UNIVERSITY OF IBADAN LIBRARY xv memory to run compared to JADE platform requiring 2.83 103 KB. The mean fault tolerance in terms of fault recovery time for EMA was approximately 50% that of JADE (327.8 ± 193.1 ms). The mean turn around time for EMA was 499.7 ± 173.0 ms and JADE was 843.3 ± 321.6 ms consequential to the time JADE spent activating platforms. The mean percentage denial of service for EMA was 14.3 ± 9.8 while JADE was 24.7 ± 18.5. Memory requirements and service delay increased with increasing number of nodes while others show no systematic change. For all the parameters tested, there were significant differences between the two schemes. The embedded mobile agent provided more efficient, dynamic and flexible solution compared to Java Agent DEvelopment framework for distributed information retrieval applications. It could be incorporated into new versions of operating systems as operating system service for universal distributed information retrieval. Keywords: Mobile agent technology, Embedded mobile agent, Operating system service, Java agent development framework. Word count: 497 1 results 1
- Mobile agent technology 1 results 1
- Operating system service, 1 results 1
- Over the recent years, sexual activities among students in Secondary Schools in Nigeria, particularly those in urban areas, are thought to be high and increasing. The resultant unwanted pregnancies and illegal abortions among these young unmarried population are creating social and health problems (Nichols, et al, 1986). According to previous research findings, included in the causative factors responsible for this unfortunate situation, cure the problems of poor knowledge of Family Life (Sex Education) and Reproductive Health Education and Contraception, negative attitude towards contraceptive services, low and ineffective use of contraceptives due to low accessibility to family planning services. Therefore, the present Knowledge, Attitude and Practices (KAP) study was carried out in order to assess the level of contraceptive awareness and utilization amongst Students in Secondary Schools in- Ibadan North-East- Local Government Area of Oyo State. After the pretesting, a total number of 766 questionnaires were finally administered to students in the Senior Classes in four (4) Secondary Schools in the Local Government Area using a combination of proportional stratified and systematic random sampling techniques. The selected four (4) schools consists of one Boys' only, Girls' only and two mixed schools. Out of this number, a total of 744 duly completed questionnaires were subsequently analysed. The result showed that 484(65.1%) respondents had the correct knowledge of some modern methods of contraception, and out of this figure, 183(37.8%) mentioned condom as a popular method of contraception among them. Although, attitudinal disposition of the respondents towards contraceptive use was as high as 76.0%, however, the results showed a very low level of contraceptive utilization among them (15.7%), Based on these findings, it is suggested that Family Life and Reproductive Health Education including contraceptive counselling services should be introduced in the secondary schools in the L.G.A. 1 results 1
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- AUC Knowledge Fountain — bepress 26 results 26
- KNUSTSpace — Kwame Nkrumah University of Science & Technology (Ghana) 2 results 2