Browsing by Author "Mvuma, Aloys N."

Now showing 1 - 6 of 6
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    Adaptive Iir Filters For Single Interference Suppression In A BPSK DS CDMA System In Rayleigh Fading Channel
    (University of Dar es Salaam, 2007-07-01) Mvuma, Aloys N.
    In this paper, effect of a single narrow-band interference (NBI) on bit error rate (BER) performance for a binary phase shift keying (BPSK) synchronous direct-sequence code-division multiple access (DS CDMA) communication system operating in a frequency nonselective Rayleigh fading channel is analyzed. Second-order adaptive infinite impulse response (IIR) notch filters with plain gradient algorithm (GA) for suppression of NBI in the DS CDMA system are proposed. A general closed-form BER expression for the DS CDMA system with NBI suppression second order adaptive IIR notch filters is derived based on the standard Gaussian approximation (SGA) method. BER expressions are then derived for the allpass filter-based adaptive IIR notch filter and adaptive IIR notch filter with constrained poles and zeros, the two structures that are commonly found in literature. It is observed that both adaptive IIR notch filter structures exhibit comparable BER performance. Extensive computer simulation results are presented to verify the accuracy and limitations of the analysis.
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    An Overview of Maternity healthcare Monitoring in Developing Nations
    (Tanzania Journal of Engineering and Technology, 2024) Kyambille, Godphrey G.; Mvuma, Aloys N.; Machuve, Dina
    A healthcare monitoring arrangement is essential for frequently monitoring a patient's health status. Specifically, maternal healthcare systems for tracking are utilized to evaluate the clinical status and monitor any abnormal condition changes during all three trimesters. This paper's objective is to conduct an extensive literature review and acknowledge earlier initiatives and studies conducted previously in maternal health care monitoring. This review focuses on accumulating information from earlier work and presents a general overview of previous studies concerning maternal health care monitoring (MHCM). The paper focuses on the maternal healthcare systems in developing countries accessed by pregnant women during the antenatal period. Furthermore, this paper highlights the challenges in the maternal health sector that include inadequate work conditions for health workers, home-based birth practices, long distances to healthcare facilities, and long waiting times in health facilities. The paper indicates the potential opportunities to strengthen maternal healthcare services and allow effective access to maternal healthcare facilities by pregnant women
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    BER of OFDM System With Multiple NBI Rejection Cascade Complex Coefficient Adaptive IIR Notch Filter
    (Scientific Research, 2012-08-16) Mvuma, Aloys N.
    In this paper, rejection of multiple narrowband interferers in a binary phase shift keying modulated orthogonal fre- quency division multiplexing (BPSK-OFDM) system is investigated. The BPSK-OFDM system in consideration oper- ates in an additive white Gaussian noise (AWGN) channel. A cascade complex coefficient adaptive infinite impulse response (IIR) notch filter with gradient-based algorithm is used to reject the interferers. Bit error ratio (BER) perform- ance of the system is studied and a general closed-form expression is derived assuming negligible steady-state leakage NBI and by estimating the decision variable as Gaussian distributed based on Central Limit Theorem (CLT). Depend- ence of the BER performance on the notch bandwidth coefficient is demonstrated by the analysis. Extensive simulation results are included to substantiate accuracy of the analysis.
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    Occlusion Handler Density Networks for 3D Multimodal Joint Location of Hand Pose Hypothesis
    (OPEN ACCESS, 2022-12-30) Tito, Stanley L.; Banzi, Jamal F.; Mvuma, Aloys N.
    Predicting the pose parameters during the hand pose estimation (HPE) process is an ill-posed challenge. This is due to severe self occluded joints of the hand. The existing approaches for predicting pose parameters of the hand, utilize a single-value mapping of an input image to generate final pose output. This way makes it difficult to handle occlusion especially when it comes from the multimodal pose hypothesis. This paper introduces an effective method of handling multimodal joint occlusion using the negative log-likelihood of a multimodal mixture-of-Gaussians through a hybrid hierarchical mixture density network (HHMDN). The proposed approach generates multiple feasible hypotheses of 3D poses with visibility, unimodal and multimodal distribution units to locate joint visibility. The visible features are extracted and fed into the Convolutional Neural Networks (CNN) layer of the HHMDN for feature learning. Finally, the effectiveness of the proposed method is proved on ICVL, NYU, and BigHand public hand pose datasets. The imperative results show that the proposed method in this paper is effective as it achieves a visibility error of 30.3mm, which is less error compared to many state-of-the-art approaches that use different distributions of visible and occluded joints.
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    QPSK DS-CDMA System over Rayleigh Channel with a Randomly-Varying Frequency Narrow-Band Interference: Frequency Tracking Analysis.
    (Scientific Research., 2010-03) Mvuma, Aloys N.
    This paper analyzes frequency tracking characteristics of a complex-coefficient adaptive infinite-impulse response (IIR) notch filter used for suppression of narrow-band interference (NBI) with a randomly varying frequency in a quadriphase shift keying (QPSK) modulated direct-sequence code-division multiple-access (DS-CDMA) communication system. The QPSK DS-CDMA signals are transmitted over a frequency non-selective Rayleigh fading channel. The analysis is based on a first-order real-coefficient difference equation with respect to steady-state instantaneous frequency tracking error from which a closed-form expression that relates frequency tracking mean square error (MSE) with the number of DS-CDMA active users and NBI power is obtained. Closed-form expressions for the optimum notch bandwidth coefficient and step size constant that minimize the frequency tracking MSE are also derived. Computer simulations are included to substantiatethe accuracy of the analyses.
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    Ubiquitous Mobile Sensing for Water Quality Monitoring and Reporting within Lake Victoria Basin
    (Scientific Research, 2014-12) Faustine, Anthony; Mvuma, Aloys N.
    As the human population growth and industry pressure in most developing countries continue to increase, effective water quality monitoring and evaluation has become critical for water re sources management programs. This paper presents the ubiquitous mobile sensing system for water quality data collection and monitoring applications in developing countries. The system was designed based on the analysis of the existing solution. Open source hardware and software was used to develop the prototype of the system. Field testing of the system conducted in Nkokonjero, Uganda and Mwanza, Tanzania verified the functionalities of the system and its practical applica tion in actual environment. Results show that proposed solution is able to collect and present data in a mobile environment.