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Design of arm movement for upper limb after stroke rehabilitation using enhanced VR-based
No full textMaster of Science in Mechatronic EngineeringEvery year, 15 million people worldwide suffer from stroke attack. Nearly six million dead and another five million are left permanently disabled. According to National Stroke Association of Malaysia (NASAM), stroke is the third leading cause of death in Malaysia after cardiovascular disease and cancer. Stroke may lead to serious disability including loss of vision or speech, muscle disability and confusion. Muscle impairment can be treated by intense use and active movement of affected limbs to stimulate the weak muscle and slowly develop the motor function which enables sufferers to slowly regain the movement of the affected limbs. Conventional stroke therapy is costly at the same time less engaging, thus virtual reality (VR) system could be the main focus of enhancing stroke rehabilitation giving the stroke patient the possibility of action involvement sense at the same time offering many other benefits such as reducing therapy cost, providing more realistic assessment and adaptable to patient condition. Currently researchers are developing various virtual reality arm rehabilitation for post
stroke patients, but less of the arm training task are design with measuring the muscle
activity and most of the movement sequence are random. In this research, 18
fundamental arm movements are analyzed using EMG acquisition system involving
deltoid anterior, deltoid lateral, biceps, triceps, flexor and extensor. The EMG signals
were pre-processed to eliminate noise. Three statistical features which are mean,
standard deviation and amount of movement (AOM) were then extracted from the EMG
signals to analyze arm movements and muscle activation. Based on the results, AOM
feature was chosen to represent muscle activity and four most activated muscles which
are deltoid lateral, deltoid anterior, biceps and triceps were identified with each having
AOM of 2.061, 1.113, 0.911 and 0.394 respectively. These results are then employed to
design movement sequences in real (physical) environment involving 2D coronal plane,
the amount of movement from all movement sequence were obtained and compared
with the ideal criterion of rehabilitation (warming up, intensive and cooling down). The
results were comparable to the proposed muscle activity pattern and the selected
movement sequences were translated into virtual environment. Final experiment was
conducted in virtual environments where subjects interacted with virtual objects using
5DT data glove and webcam, results show that movements made in VE trigger higher
AOM compare to real environment but have comparable pattern. Final experiment to
assess the consistency of the VR based system, SD of AOM for each movement are
calculated with the highest SD of 0.501 for more intensive movements which is
acceptable as movement style are not fixed between subjects. Generally, the
experimental results show that it is possible to design optimum functional movements
for arm rehabilitation after stroke. The system was tested using healthy subjects and
revealed with potential rehabilitation system for stroke patient
Effect of acid treatment for reducing pores clogging in polyvinyl alcohol grinding stone
No full textMaster of Science in Materials EngineeringGrinding stone after aluminum disk grinding was clogged by debris loading after used for a certain period of time. The clogging pores modified the surface structure of grinding stone thus resulting in scratching of aluminum disk during grinding process. The aim of this thesis is to determine the properties of raw (control) and clogged (sample) grinding stone thus reduced the clogging problem in grinding stone using acid treatment. The grinding stone were characterized to understand the factor of pore clogging. Morphology analysis by
scanning electron microscope (SEM) and elemental analysis using X-ray fluorescence (XRF)
spectrometer found that, the clogging area were consist of debris from aluminum disk
grinding. Pore size and distribution in unused grinding stone from micrograph structure were
varied and inhomogeneous. Since size of debris cannot be controlled, there were some of
debris size that larger than the pore size. Even though pore were connected each other as a
tunnel for debris removal, the bigger debris size cannot flow through small hollow of pore
which cause the loading of debris resulted in pore clogging. The pore size was not uniform,
density and hardness (Shore A Durometer) of control grinding stone also were varied. The
grinding stone were treated with three different types of acid (citric, phosphoric, and oxalic
acid) at concentration of 0.5, 1.0, and 1.5 M with treatment time of 1, 30, and 60 minutes.
Porosity results and micrograph structure of the grinding stone indicated that the acids can
caused clogging in control grinding stone but had the ability to produce pores for sample
grinding stone. At concentration of 1.0 M, oxalic acid shows the highest clogging removal
compared to citric and phosphoric acid. However, elemental analysis by energy dispersive
x-ray (EDX) spectroscopy shows that oxalic acid tend to remove silicon carbide (SiC)
abrasive of grinding stone and phosphoric acid has the tendency to deposit in grinding stone.
As conclusion, 1.0 M citric acid and stirring time of 1 minute was the optimum parameter
for dissolving the pore clogging in sample grinding stone. Besides not affecting aluminum
substrate, citric acid also the best chelating agent to dissolute aluminum debris in grinding
stone while does not chelating with silicon carbide
Effects of student's satisfaction and co-creation on the relationship between attitudinal factors and destination loyalty: evidence from international students in Malaysian public universities
No full textDoctor of Philosophy in ManagementIn view of the ever increasing attrition rate of international students at study destinations occasioned by increased education marketization, reduced public budgetary allocation, globalization, internationalization and stiff competition, this study aimed to fill research vacuum by proposing and validating destination loyalty model using new paradigm of relationship marketing in higher education sector. Drawing from a new marketing innovation concept of service dominant (SD) logic and social exchange theory, this study examines the effects of students’ satisfaction and Co-Creation on the relationship between attitudinal factors and destination loyalty. A total of 498 undergraduate and post graduate international students from Malaysian public universities participated in the survey. The result of partial least square (PLS) path analysis supported all but two variables in the
hypothesized direct relationship to students’ satisfaction and destination loyalty.
Specifically, attitudinal factors of service quality, perceived value and personal reasons
were found to have significant relationship with destination loyalty. Similarly, service
quality, perceived image and perceived value significantly influenced students’ satisfaction.
The intervening variables of students’ satisfaction and Co-creation also show significant
relationship with destination loyalty.However, perceived image was not significant to
destination loyalty. Personal reason was also not significant with students’ satisfaction. The
bootstrapping result of students’ satisfaction as mediator was significant except with
personal reasons. The results of the analysis also suggest that Co-Creation moderates the
relationship between students’ satisfaction and destination loyalty. Taken together, the
findings of this study lend empirical support to the view that joint creation of value between
consumers and service providers will confer competitive advantage in service relationship.
Hence, knowledge of FP-4 in SD logic will assist universities management to grow their
student’s profile for sustainable competitive advantage. It is recommended that emerging
destinations should concerntrate on retention through unique service provision. Malaysian
public universities particularly should focus on the implementation of students’ satisfaction
and Co-Creation to earn students’ loyalty and increase inbound international students for
sustainable internationalization benefits
Human activity recognition based on ELM using depth Images
No full textDoctor of Philosophy in Computer EngineeringHuman Activity Recognition (HAR) has gained considerable research interest in recent
decades due to its vast applications especially in the fields of medicine, surveillance,
human-machine interaction, gaming and entertainment. Feature extraction is a key step in
HAR algorithms. However, at present most research is focused on common features such as
spatial domain and frequency domain features. Such features lack context and are not
comprehensive in nature. Unfortunately, building a comprehensive feature space of human
activities is difficult due to the vastness and uncountable nature of human actions. This
leads to the challenging problem of designing a HAR system that uses context-based
feature extraction of human actions. In this work a comprehensive contextual feature space
for human activity recognition is presented using depth image,the total number of fratures
is 11. in classification aspect, extrem learning machine uses only a single iteration in the
training stage to determine the output weights. extrem learning machine is extremely
effective as it tends to achieve the global optimum compared to the traditional FNN
learning methods which might get trapped in a local optimum. The drawback of ELM
algorithm holds an infinite number of degrees of freedom for approximating a given data
set. These infinite degrees of freedom are a consequence of the random nature of the
weights assigned between the input and the hidden layer. A possible potential improvement
in performance in this research can be achieved by assigning the weights based on an
objective functionan optimization of the (ELM) using the meta-heuristic. Harmony Search
Algorithm which is a part of meta-heustric and Tansig activation function which remove un
needed hidden neuron are also presented in this work. The presented approach hence
solves the problem of the infinite degree of freedom of the input weights as well as
restricting the number of neurons in hidden layer, thus increasing the performance of the
ELM algorithm. The optimized ELM algorithm is then used to perform the classification of
the developed context based on feature space. The accuracy achieved was 100% during
training and 94.95% during testing with throw action and 100% during training and 100%
during testing without throw action. Gready optimization of the ELM with HSO has
acehived an accuracy of 94.95%. Moreover, 60% of the features have achieved an accuracy
of over 100%. Thus, the approach can be utilized to perform the human activity recognition
for various purposes
Design and analysis of 90 nm two-stage operational amplifier using floating-gate MOSFET
No full textMaster of Science in Microelectronic Systems Design EngineeringLow voltage, low power dissipation, high gain and matching are some of the concern when designing an analog circuit. A very low voltage can increase battery lifetime and integration density as market demands. Floating-gate Metal-Oxide-Semiconductor (MOS) also known as FGMOS is a new technology design that has been introduced as an element in low voltage circuit design in CMOS technology. FGMOS technique has been reported as low voltage and low power design application for increasing the battery lifetime due to its lower threshold voltage. The operational time of the FGMOS transistor can be improved by controlling the threshold voltage without reducing the feature size of the transistor. This research focuses on analyzing and comparing the simulation application of FGMOS technique with conventional MOSFET for various circuit designs. Capacitor ratio of 0.5
with value of 2 fF of the FGMOS transistor is chosen in order to have most stable output
result. Proposed FGMOS operational amplifier circuit consists of two stages namely input
differential circuit and output buffer stage that contributes in amplifying an input signal.
The circuit simulations are analyzed using Full Custom Synopsys software with 90 nm
CMOS technology. The simulated results show approximately 42 dB of gain with 3dBbandwidth
of 233 kHz, unity gain bandwidth of 23.6 MHz and total power dissipation of
203.3520 mW. In conclusion, the proposed FGMOS designs show comparable result with
conventional MOSFET designs. However, the proposed design performance can be
improved in further research due to its lower threshold voltage
Non-linear features and feature selection algorithms for speech based prediction of body mass index (BMI)
No full textDoctor of Philosophy in Mechatronic EngineeringObesity and overweight have been a growing concern due to their negative impacts on human‘s health. Obesity is considered as a major cause of some serious diseases such as diabetes, cardiovascular diseases, and metabolic syndrome, and it has become epidemic. Today, body mass index (BMI) is widely used as a tool to classify normal weight, overweight, underweight and obesity. These measurements are sometimes not suitable for remote healthcare or u-healthcare supporting general treatment and emergency medical service in real time at remote locations. The researchers have explored the association between speech recognition and BMI. Speech signals have a close relation with BMI status, which is predicted by a combination of key features. The purpose of this research work is to predict BMI status (normal, overweight and obese) using speech signal without weight and height measurements. In this research work, wavelet packet based nonlinear entropy features and feature selection algorithms were proposed to predict BMI status via speech signal of normal, obese and overweight subjects. The
recorded speech signal (/ah/ sounds) were decomposed up to level five using wavelet packet transform (WPT). Several features were extracted from the wavelet packet coefficients and an Analysis of Variance (ANOVA) test
The effect of flame retardant additive on the properties of kenaf/polyurethane foam composite
No full textMaster of Science in Materials EngineeringThis research is mainly focused on the preparation and characterization of polyurethane foam (PUF) with the addition of kenaf fiber and flame retardants, which are expandable graphite (EG) and aluminum hydroxide (ATH). Kenaf core fiber was
ground into 63 μm in size and was used as the natural filler in the PUF at different amount which are 1, 3, 5 and 7 wt%. Various amount of EG (5, 10 and 15 wt%) and ATH (2, 4 and 6 wt%) was incorporated into the PUF. EG was milled for 1 hour and 30
minutes in a ball mill machine which in turn produces EG particles with 100 μm in size. The composites were prepared by the mixture of palm oil based polyol and isocyanate with the ratio of 1:1.1. The PUF composites were prepared through mixing process by using a mechanical stirrer with 2000 rpm speed. The effect of different amount of filler loading and flame retardant on the PUF was studied to determine the rising time, density, compression properties, flammability behavior, thermal analysis and
morphological studies. From the results obtained, it showed that PUF filled with kenaf fiber takes shorter rise time compared to the PUF filled with flame retardants. While, density values were increased with the increasing amount of filler and flame retardant
into the PUF matrix. For mechanical study, compression strength and modulus of the PUF composites was reduced as the amount of kenaf fiber and flame retardants were increased. The mechanical strength was improved for PUF/15EG and PUF/KF/15EG due to the large surface area provided by the pulverized EG particles. Based on LOI and
flammability test, it was recorded that PUF with the highest amount of flame retardants and with the presence of kenaf fiber (PUF/KF/6ATH/15EG) shows excellent flame retardancy properties
Optimization of P-I-N rectifier diode for yield and robustness improvement using DOE
No full textMaster of Science in Nanoelectronic EngineeringRestricted ItemThe Power Rectifier (P-i-N rectifier) is one of the widely used diode in high power semiconductor devices as circuit protection. This popularity comes from excellent reverse voltage blocking and fast switching time. As a result, the exploration on the power rectifiers to make the device more robust and competitive in the market is boundless, which aims for continuous improvement on the electrical characteristics. In general, the P-i-N rectifier is consists of a highly-doped P-N junction with a low doped intrinsic region sandwiched in between the regions. Such characteristics have made the design of as high as 1000 V reverse
voltage diode is possible by lowering the switching time. This thesis describes the research work done on the power rectifier by exploring the device characteristics and optimizing the input responses using Design of Experiment (DOE) techinique. Parameter such as epitaxial layer specification, junction drive time and also other internal fabrication processes were optimized, to produce a desired device robustness and yield improvement. The main electrical characteristics namely reverse recovery lifetime, reverse voltage, reverse leakage current and such, were investigated and analyzed. The results show that with implementation
of optimized epitaxial thickness and resistivity, the P-i-N power diodes were able to withstand high reverse voltage. The optimum epitaxial thickness for 600 V device is at 96 μm. The epitaxial thickness is a dominant factor as compared to epitaxial resistivity and boron diffusion time. Next, the variation in junction drive time shows a direct relationship between the junction depth of the P-i-N rectifier to the reverse voltage for 200 V device. Each additional 60 minutes in boron diffusion time will increase the device reverse voltage by 30 V. Lastly, the investigations are about reverse recovery lifetime and forward voltage of the power diode
Junctionless transistors: parametric study with conventional doping in MOSFETS
No full textMaster of Science in Nanoelectronic EngineeringThe advancement of today technologies has been aggressively developed as the needs of current technology that becoming competitive and demanding to accommodate human lifestyle. The electronic gadgets drive the market with the requirements to provide efficient chip functionality at higher speed and extra functionality. This has become more challenging as the transistor density and performance are aggressively increasing. Thus, continuous downscaling of the conventional transistor will lead to severe short-channel effect (SCE), and one of the solutions is a ultra-shallow junction. Ultra-shallow junction is very challenging as it increases in fabrication cost and difficulty in the fabrication process. In this study, the channel, drain, and source have the same type of doping where the ultra-shallow junction has been eliminated. Hence, it is called junctionless. There will
be no diffusion will take place where it will remove the high cost for ultrafast annealing
techniques. Besides that, it allows the transistor to be fabricated with a shorter channel if
the gradient of the doping concentration is zero between drain and channel or source and
channel. This operation principle of the junctionless transistor is investigated through
numerical simulations using technology computer aided design (TCAD) simulation tools.
Firstly, the device performance of 3-Dimensional (3D) silicon-on-insulator (SOI)
junctionless transistor (JLT) with 100 and 10 nm gate lengths, have been compared to the
3D SOI junction transistor (JT) with the same gate length. In order to achieve full
depletion, the parameters such as metal gate workfunction, doping concentration, drain
bias, and dimension are considered in the simulation process. The digital figure-of-merits
characteristics such as threshold voltage (VTH), on-current, subthreshold slope, and draininduced-
barrier-lowering are the main parameters that have been investigated. Following
next is the characterization on the analog and radio frequency (RF) figures-of-merit.
Based on the simulations, 1) the designated JLT device is more suitable to the higher gate
workfunction of more than 5.0 eV whereas the designated JT device is more suitable with
mid-gap values of gate workfunction of 4.6 eV. 2) the JLT transistor requires high gate
work-function to have control over the channel. 3) the JT device is less sensitive to the
variation of silicon body thickness (TSi) and width (WSi) compared to JLT. Lastly, the
device performance on analog and RF figures of merit shows that no significant different
between JLT and JT with the latter case shows slightly better performance, related to
lower gate-to-gate capacitance (Cgg)