UniMAP Library Digital Repository
Not a member yet
77924 research outputs found
Sort by
Feature extraction and classification algorithms for assessing muscle condition using multi sensors
No full textMaster of Science in Biomedical Electronic EngineeringHamstring muscle strain injury is the most common injuries in sport environment especially in football. Beside sport, dancing is another physical activity that has high risk for hamstring muscle strain injuries. Muscle fatigue is one of the risk factors that
cause muscle injury. Muscle fatigue occurs when muscle fail to maintain desired muscle strength. The aim of this work is to assess and distinguish muscle fatigue using 3 different myograms (Electromyogram, Mechanomyogram and Acoustic myogram). To achieve the aim of this project, 3 different myograms were recorded simultaneously from hamstring muscle (Biceps Femoris and Semimembranosus) during isometric contraction with different loads (5, 7.5 and 10kg). 20 healthy male subjects were
recruited in this work with aged 22.4 ±2.6 years. The recorded myograms were denoised
and segmented. Pearson correlation and linear regression were applied on 9 time and
frequency domain features (were extracted from each frame of each myograms) to find
the behavior of the myograms and relationship between the myograms. Based on the
pearson correlation results there are a strong relationship between AMG and EMG
signals and a weak relationship between MMG and EMG signals. However, the
relationship of MMG and EMG signals becomes significant when the load is increased.
Two types feature sets were used to classify muscle condition and there are
conventional features set (CFS) and M-band wavelet transform based feature set (MFS).
In CFS, 16 features were extracted from each myograms, which were used in previous
studies to assess muscle condition. In MFS, the recorded myograms were decomposed
using 4-band wavelet transform and 9 features were extracted from each node of each
myograms. Therefore, 108 features were generated for each myograms. The feature sets
of EMG, MMG and AMG of CFS and MFS were augmented to form a new feature set.
Two stage feature selection was used to reduce feature space in the new feature set. In
stage I of features selection, linear locally embedding (LLE) was used. New reductive
feature space was used in stage II for feature selection. In that stage, binary particle
swarm optimization (bPSO) was used. k-nearest neighbor (k-NN) classifier was used to
classify muscle condition (non-fatigue or fatigue) by using individual myogram feature
sets, concatenated / augmented feature sets and after 2 stage feature selection feature
sets. In the individual assessment, EMG feature sets have obtained high accuracy.
However, compare with the concatenated feature sets, this feature sets have given high
accuracy. Two stage feature selection was applied to the concatenated feature sets and
the features were reduced by 69% and 89% for CFS and MFS in stage 1 respectively. In
stage 2 the features were reduced by 7% and 40% for CFS and MFS respectively. The
classification result was improved to above 75% and 92% for CFS and MSF
respectively. It can be conclude that, the combination of three myogram provides more
useful information than a single myogram
Synthesis of sustainable binary calcium monosilicate ceramics from bio-waste: effect of sintering temperature on microstructure and electrical properties
Get PDFLink to publisher's homepage at http://ijneam.unimap.edu.my/This study was conducted to synthesise calcium monosilicate ceramics using rice husks and
raw eggshells and investigated the effect of sintering temperature on the physical,
microstructure and electrical properties of the final product. The high content of calcium
and silicon in eggshells and rice husks, respectively promote the use of waste materials in
the production of calcium monosilicates by mixing in a molar ratio 1CaO:1SiO2 and fired at
different sintering temperatures for 2 hours with a heating rate of 10°C/min. A good
correlation between sintering temperature, structural, microstructure, and electrical
properties of calcium silicate was observed. The structural and morphological evolutions
were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM)
equipped with electron dispersive X-ray analysis (EDX). XRD analysis showed that the main
crystalline phases of synthesised calcium monosilicate are pseudowollastonite (ICSD 98-
005-2598) at 1250°C, and the phases of SiO2 also exist in different types of minerals. Besides,
a small amount of larnite, Ca2SiO4 was traced at 1100°C and 1200°C. Fourier Transforms
Infrared (FTIR) spectra showed the presence of characteristic functional groups in the
precursor powder. In Nyquist plots, the summit frequency of the dominant arc decreases
with increasing sintering temperatures. It may be attributed to the co-effect of the grain size
and pore. A larger value of impedance at a lower frequency suggests an essential role of
boundaries in governing the electrical properties of the sintered ceramics. As the sintering
temperature increases, the microstructure of the sintered samples becomes denser while
conductivity performance decreases. This is due to the reduction of particle interfaces and
charge transfer
Development of SOA-MZI based logic gates and all-photonics flip flop
No full textMaster of Science in Microelectronic EngineeringPhotonics logic gates are actually logic gates that performs various logical functions such as AND, OR and NOT but instead of using electrons, they operate on using light as the main mechanism. XOR logic gates are commonly consist of various components such as optical amplifiers and couplers. These XOR logic gates also apply some of the optical nonlinear effects such as the Cross Gain Modulation (XGM) and Cross Phase Modulation (XPM) as their main operations. Three XOR photonics logic gate configurations (XOR TOAD, XOR SOA-MZI XPM and XOR SOAXGM) are analysed and compared in terms of generated power, optical signal-to-noise ratio (OSNR) and Bit Error Rate (BER). The highest generated power is recorded by XOR TOAD at
23.5 dBm. The XOR SOA-MZI XPM yields the highest OSNR with 109.6 dB and the best BER is observed in the XOR SOA-MZI XGM with the value of 4.42 x 10-22. Eye diagram pattern wise, XOR TOAD showed the widest eye compared to others. All optical flip-flop is also performed in this work which perceived 12 number of ON states with output power of 0.75 mW at 20 Gbps.
Whereas at 10 Gbps, there are only 6 ON states with output power of 2.2 mW. This deduces that running at a faster data rate will yield a higher number of ON states but having lower output power. Four SOA-MZI logic gates configurations AND, NOR, OR and NAND are compared in terms of output power. The AND and the NOR SOA-MZI logic gates depicted low output power of 1.220
dBm and 2.446 dBm, respectively. While the OR and the NAND SOA-MZI logic gates demonstrated high output power of 21.738 dBm and 21.018 dBm, respectively. In summary, the XOR SOA-MZI XGM commemorated the best performance among other XOR logic gate setups since it has moderate values of generated power and OSNR, high BER value and comprehensive
eye diagram pattern, which concludes minimum noise in the configuration. In all optical flip-flop observation, the higher data rate yields double ON states output but low output power. Finally, in the SOA-MZI logic gates utilizing two SOAs in the arrangement, the output power is small due to the limiting effect by the SOA’s saturation
Parametric identification of flexible beam system using evolutionary algorithm
Get PDFMaster of Science in Manufacturing EngineeringAn application of flexible structures in engineering is spread extensively due to lightweight property and technical importance. Before implementing the system, the dynamic behavior of the system needs to be studied by developing a mathematical model. The model-based approach like finite element method which commonly used in modeling usually required a wide knowledge on the system to be studied and involves complex equations. In system identification technique, the conventional parameter estimation is commonly applied and the limitation is, it may cause the solution trapped in local optima and reduce the efficiency of the model. Therefore, in this study, the model of flexible beam is developed by using system identification method which is based on experimental data collected from the experimental rig and using evolutionary algorithm (EAs) as estimation technique. This research provides a new platform for other researcher to develop a model based on system identification technique using EA’s for other system or application. Other than that, it also delivers a basis for future study on analysis of the performance EAs in terms of different parameter settings in comparison with other algorithms. An attempt of obtaining the linear model is accomplished by developing an experimental rig of flexible beam using square wave signal with mixing resonance frequency to collect input-output data. Auto-regressive with exogenous inputs (ARX) is chosen as a model structure of the system. The coefficient parameters of model structure are estimated via EAs such as firefly algorithm and bat algorithm. A few sets of parameter settings for FA and BA are tested to examine the effect of settings to the performance of model. The best models obtained from each estimation method are compared with least squares algorithm and validated using mean square error (MSE) and one step-ahead prediction (OSA). The main result shows that FA-estimation has MSE of 9.46E-5 which is the lowest among all the estimation method and BA-estimation also outperformed LS-estimation (1.16E-2) by getting lower MSE which is 2.70E-4. Overall of this study proved that evolutionary algorithm able to produce better performance than conventional algorithm. Firefly algorithm and bat algorithm is effective and capable to be used in this area of study like other engineering applicatio
A compact and high gain circularly polarized antenna for CubeSat S-band application
No full textMaster of Science in Communication EngineeringThis project focuses on a compact antenna with high gain and circular polarization for S-band CubeSat application. CubeSat is categorized as a type of pico-satellite with a dimension of 10 x 10 x 10 cm3. By utilizing the component-of-the-shelf (COTS), this class of pico-satellite is capable of reducing the development cost and time compared to commercial satellites in segments such as space research, earth observation, inter-satellite communication, and the educational purpose. Due to the CubeSat’s size and weight constraints, most of their antennas are integrated with deployment mechanisms. One of the most popular deployable mechanisms used in CubeSats is the tape spring mechanism. In this project, two types of high gain circularly polarized antenna is designed to comply with 1U and 3U CubeSat at S-band frequency. A compact circularly polarized antenna is designed with a size of 55 x 55 x 0.85 mm3. The antenna operates with at least -10 dB of reflection coefficient, at least 3 dB of axial ratio and a gain of 3.84 dBi at 2.4 GHz. The antenna propagates with a right-handed circular polarization (RHCP) at 0° azimuth, and left-handed circular polarization (LHCP) at 180° azimuth. Such gain level needs to be improved for long-range CubeSat communication. A reflectarray is then designed to obtain an improved simulated gain of 10.49 dBi, satisfactory impedance and axial ratio bandwidth, with propagation directed at 29° azimuth. Despite its overall larger size of 297 x 330 x 0.635 mm3, and a focal length of 243 mm, it is still applicable for a 3U CubeSat together with a tape spring based deployment mechanism. Meanwhile, the reflectarray feed is also integrated on the CubeSat with its separate deployment mechanism. The initially designed circularly polarized antenna is also integrated with an artificial magnetic conductor (AMC) plane, which resulted in both gain enhancement and back radiation reduction. Since the initial antenna produces a bidirectional radiation pattern, the AMC plane reduced its back radiation and converting it into a unidirectional pattern. With a dimension of 99 x 99 x 21.485 mm3, the AMC plane increased the gain up to 7.7 dBi with RHCP mode. Besides that, a 19.16 % 10 dB impedance bandwidth and 10.4 % of 3 dB axial ratio bandwidth are achieved at 2.4 GHz. Due to the required gap of 20 mm between antenna and AMC plane, it has been integrated on the CubeSat using a simple spring coil deployment mechanism
