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Gas source localization via behaviour based robot and weighted arithmetic mean
No full textMaster of Science in Computer EngineeringThis research is concerned with the localization of gas source in a dynamic indoor environment problem using a single mobile robot system. Since the environment is unknown to the robot, an intelligent algorithm is required to enable the robot to traverse
through the environment without any interruption from obstacles. All experiments were done on an experimental testbed consisting of a large gas sensor array (LGSA) to monitor real-time gas concentration within the testbed. The measurements from the LGSA were taken as the ground truth and were useful as it can be compared to the measurements taken
from the gas sensors on the mobile robot. A pattern tracking system was also utilized to
record the robot's odometry. Initially, two preliminary experiments were conducted to
better understand the conditions within the experimental testbed and the gas sensor's
performance within the environment when the robot is moving at different speeds. From the
preliminary experiments, we can confirm that the conditions within the testbed are indeed
dynamic and gas sensor's performance differs when the mobile robot is moving at different
speeds. We then proceed to implement two algorithms (i.e Zig-Zag and Braitenberg) to test
the robot's performance in traversing through the experimental testbed while taking gas
sensor measurements. The Braitenberg algorithm was separated into two variants (i.e Repel
and Attract) which then were implemented with the mobile robot
Adsorption of basic red 46 dye using sea mango (cerbera odollam) activated carbon
No full textMaster of Science in Bioprocess EngineeringThe limited source of raw materials for production of activated carbon has increased the
price of commercial activated carbon price. Due to the presence of lignin and cellulose in
sea mango make it as new potential for activated carbon. Sea mango activated carbon was
prepared by chemical activation using potassium hydroxide (KOH) at different
carbonization temperatures, which are 500ºC (AC500) and 600ºC (AC600) under nitrogen
(N2) gas flow. The activated carbon prepared together with sea mango precursor (SMP)
was characterized using Scanning Electron Microscope (SEM) and Brunaer Emmet Teller
(BET) for surface morphology and specific surface area, respectively. The result showed
that the surface of AC500 and AC600 has undergone some alteration where some new
pores were developed. The specific surface area measured for SMP, AC500 and AC600
were 0.03 m2/g, 108.79 m2/g and 451.87m2/g, respectively. Fourier Transform Infrared
Spectroscopy (FTIR) use to analyse functional group showed band transition between the
three samples which indicated that chemical transformation had occurred during activation
process. Analysis of Total Ash Content (TAS) has shown that the ash content increased in
both AC500 (38.97%) and AC600 (41.82%) compared to SMP (2.53%) whereas AC500
has better yield compared to AC600. In order to study the performance of sea mango
activated carbon, AC600 was further used in adsorption of Basic Red 46 dye in batch
process. The effects of operating parameters, initial pH solution, adsorbent dosage, initial
dye concentration and adsorption temperature were varied where the result obtained
indicated that all parameters have played important roles in the adsorption process. High
initial dye concentration has resulted in low adsorption of Basic Red 46 dye with the best
initial pH solution was 11. It was found that the removal of Basic Red 46 dye increased
with the increasing amount of adsorbent dosage and adsorption temperature. Interaction
between parameters was studied using Response Surface Methodology (RSM). The
optimum parameters were recorded at 150 mg/L initial dye concentration, initial pH
solution of 11.00 and 1.00 g/L adsorbent dosage with R2 of 0.9943. Moreover, from the
isotherm and kinetic analysis conducted, the results showed a monolayer adsorption as the
data fitted well on Langmuir isotherm model and pseudo-second-order kinetic model with
R2 values closed to 1
Enhanced partial transmit sequence technique with improved partitioning and phase factor methods for orthogonal frequency division multiplexing systems
No full textDoctor of Philosophy in Communication EngineeringOrthogonal Frequency-Division Multiplexing (OFDM) is an important technology that enables transmission at high data rates. However, a major problem of OFDM systems is the high peak-to-average power ratio (PAPR) of OFDM signals. High PAPR drives the transmitter power amplifier (PA) into saturation, and causes nonlinear distortions. In order to improve the performance of the OFDM systems, PAPR should be significantly reduced at low computational complexities. Motivated by the requirement of efficient PAPR reduction techniques associated with multi-carrier systems, such as OFDM, this research explores the state-of-the-art PAPR reduction techniques and proposes new signal processing techniques that can achieve a minimum PAPR at lower computational complexities for given system parameters that are compatible with the appropriate standards. This thesis proposes a novel flexible and practical scheme for PAPR reduction, based on partial transmit sequence (PTS) technique, which is a well known probabilistic approach to the PAPR problem. This approach decreases the PAPR without any significant performance loss, adverse impact, or changes to the system. The proposed approach eliminates the known drawback of current PTS techniques, namely the high implementation complexity to achieve a significant PAPR reduction. In this thesis, three methods have been proposed to realize minimal PAPR with low computational complexity in an OFDM system. These approaches enhance both
partitioning and phase rotation schemes within the PTS framework in order to minimize PAPR at lower computational complexities. The performances of the approaches were evaluated via computation of PAPR achieving these approaches and comparing them with the PAPR realized by traditional PTS schemes. The following are the principal contributions of this thesis. First, a new PTS partitioning method, namely the Blocked Interleaved Partitioning (BIP), which leads to better PAPR reduction performance, is proposed. Second, the Smallest Correlation Phase Vector (SCPV) and Blocked Random Phase Selection (BRPS) are proposed to determination the optimal phase rotations. Combination of proposed partitioning and phase rotation schemes resulted in two proposed PAPR reduction schemes namely BIPSC-PTS and BIPBR-PTS respectively
Variational Monte Carlo study of light nuclei
No full textDoctor of Philosophy in Theoretical PhysicsAn outstanding problem in Variational Monte Carlo (VMC) calculations with realistic interactions like Argonne V18 and Urbana IX three-body interactions is that p-shell nuclei turn out to be grossly under bound as compared to the Green’s Function Monte
Carlo (GFMC) calculations. A similar situation exists in Diffusion Monte Carlo calculations with somewhat simplified interactions. In this thesis, we improve upon the VMC calculations by bringing about several variations in the established procedure of
performing variational calculations. In the first variation, the effect of the errors as a
function of the number of particles in the variational wave function are analyzed and
then a correction through expanding the radial part in terms of a complete set are made
and treat the expansion coefficients as variational parameters. Second variation consists
in modifying the variational wave function structure. The state of the art variational
wave function for s- and p-shell nuclei consists of two parts, where the first part is a
Jastrow part operated upon by a symmetrized sum of two-body operatorial correlations
and in the second part this outcome is then operated by a sum of unity, operatorial threebody
and spin-orbit two-body correlations. A considerable improvement is obtained
over the binding energies, wave functions and variance for the light nuclei 3H, 4He and
6Li by using these two variations. We obtain noticeable improvement in the quality of the
wave function and lowering of the energies compared to earlier results. The new energies
are –8.38 MeV, –28.07 MeV and –29.90 MeV for 3H, 4He, and 6Li respectively. All the
computations have been taken away on a multiprocessor machine developed
indigenousl
Modelling and simulation of mixed quieuing server pharmacy system with adjustable parameters
No full textMaster of Science in Engineering MathematicsThis dissertation involves discrete event simulation (DES) as a type of computer based modelling that imitates a real world system of pharmacy unit. Queuing theory that is used to model and analyse the characteristic of queuing system at the pharmacy unit of Hospital Tuanku Fauziah, Kangar. The input of this model is based on statistical data collected for 20 working days in June 2014. Currently patient waiting time of pharmacy unit is more than 15 minutes. The actual operation of the pharmacy unit is a mixed queuing server with M / M / 2 queuing model where the adjustable parameter is refer to the pharmacist. Discrete event simulation method and ProModel software is used to simulate the queuing model and to propose the improvement for queuing system at
pharmacy unit. Waiting time for each counter is analysed and found out that Counter 3
and 4 has the highest waiting time which is 16.98 and 16.73 minutes. Three scenarios;
M / M / 3 , M / M / 4 and M / M / 5 are simulated by using ‘What If Analysis’ and
waiting time for actual queuing model and experimental queuing model are compared.
The simulation results show that by adding the server (pharmacist) will reduce patient
waiting time. Almost 50% average patient waiting time is reduced when one pharmacist
is added to the counter. However, it is not necessary to fully utilize all counters because
eventhough M / M / 4 and M / M / 5 produced more reduction in patient waiting time,
but it is ineffective since Counter 5 is rarely used and current average patient waiting
time for Counter 6 is 1.99 minute
An approximate arithmetic progression approach for image filtering technique
No full textMaster of Science in Engineering MathematicsImage have a significant importance in many fields in human life such as, in medicine, photography, biology, astronomy, industry and defense. Thus, it attracts the attention of large number of researchers, among them those interested in preserving the image
features from any factors that may reduce the image quality. Removing noise from the image by retaining the features of this treated image remains a standing challenge for the researchers in image processing field. Therefore, this study is carried out to propose and implement a new filtering technique for removing Salt & Pepper noise from the digital
image. This technique permits the narrowing of the gap between the original and the
restored images, visually and quantitatively by adopting the mathematical concept
(arithmetic progression) due to its ability in modelling the variation of pixels intensity in
the image. The principle of the proposed filtering technique relies on the precision, where
it keeps the uncorrupted pixels by using effective noise detection and converts the
corrupted pixels by replacing them with other closest pixels from the original image at
lower cost and with more simplicity. The results illustrate that the proposed filtering
technique gives an acceptable performance compared to the existing methods whether
visually or quantitatively with peak signal-to-noise ratio (PSNR) and mean squared error
(MSE)
Wireless heart rhythm abnormality monitoring kit based on Raspberry PI
No full textMaster of Science in Biomedical Electronic EngineeringAccording to statistics, heart diseases kill about 29,360 people every year in Malaysia
and about 600,000 people in America. Heart monitoring kits are only available for
bedridden patients, and the traditional heart monitoring kits have many wires that are
obstacle patients’ mobility. Most of the existing heart monitoring kits can detect only
one or two types of the heart diseases. Thus, the current study proposed a wireless heart
monitoring kit to monitor patients with a heart abnormality. The proposed kit can detect
and classify four arrhythmia types as well as normal ECG with high accuracy. The
design and development of the wireless heart abnormality monitoring kit (WHAMK) in
this research were divided into three stages. These stages are the development of an
arrhythmias detection and classification method using artificial intelligence approach,
design and implementation of the kit hardware, and design and coding of the kit
software. Arrhythmias classification approach is divided into four stages, namely
obtaining the electrocardiograph (ECG) signals, preprocessing, feature extraction and
classification. The arrhythmia database of Massachusetts Institute of Technology (MIT)
and signals from an ECG/arrhythmia simulator were used for training and testing of the
WHAMK. There were 400 signals from MIT database and 116 signals from the
ECG/arrhythmia were used. The ECG signals consist of normal sinus rhythm (NSR),
premature atrial contraction (PAC), premature ventricles contraction (PVC),
Bradycardia and Tachycardia. The features extraction methods are based on discrete
wavelet transform (DWT) and statistical features. The statistical features are mean
absolute value, root mean square, standard deviation, and median. The library support
vector machine (LIBSVM) was used to classify the ECG signals. The results indicated
that the statistical feature extraction approach gave a better result than the DWT when
these two approaches were tested individually by using LIBSVM. The hardware of the
kit is divided into two parts, namely ECG body sensor (EBS), and processing and
displaying unit (PDU). EBS design involves ECG electrodes, ECG conditioning circuit,
microcontroller, rechargeable battery, charging control module and Bluetooth module.
PDU consists of Raspberry pi computer, Bluetooth module, 7-inch colored screen and
power supply. Arrhythmias classification approach was developed by using statistical
features and LIBSVM. They were implemented in the kit software to enable it to detect
the arrhythmias in the real-time and fully automatically. The kit can detect and classify
four arrhythmia types as well as NSR. These types of arrhythmia are PAC, PVC,
Bradycardia and Tachycardia. The proposed kit gave a good accuracy for detecting and
classifying Arrhythmia with the overall accuracy of 96.2%
Work-life balance: Telepressure and marital status interaction
No full textLink to publisher's homepage at https://ijbt.unimap.edu.myTelepressure in the workplace, represented as an employee's concern and urge to reply fast to work-related communications through the use of information and communication technologies, which may be concerned about poorer employee work-life balance and the employee’s inferior well-being. This study aims to identify the relationship between telepressure and work-life balance. This study further tested the moderating role of marital status between telepressure and work-life balance. Data for the present study was collected from 558 volunteers from Malaysia by getting responses through online surveys. The employing simple technique was convenience. Data was analysed through PROCESS macro using SPSS. Results showed the significant influence of telepressure on work-life balance. Results further confirmed that employees' marital status moderates this relationship of telepressure on work-life balance. Results also found that the telepressure is seen high among married people but low among single people. Present study’s model is supported by the Role Conflict Theory. Which covers the conflicts arises between work and personal life of employees as a result of extra demand of work. This is a unique combination that is important in the post-COVID context, and it was less explored previously. While no study has been found covering "telepressure->marital status->work-life balance" in context of Malaysia previously
Non-invasive jaundice measurement using magnetic induction spectroscopy technique
No full textMaster of Science in Biomedical Electronic EngineeringNeonatal jaundice is a yellowing of the skin and other tissues of newborn infants. The vast majority of newborn infants suffers from jaundice during their first week of life. Therefore, the heel puncture technique is used to determine the total serum bilirubin (TSB) by taking blood sample from the baby’s heel. This approach, however, may cause skin infection and lead to more damage. Other approach such as jaundice meters may possess some vulnerability due to the fact that the device implements optical based measurement, in which the value of light absorption varies for every skin colour. Thus, Magnetic Induction spectroscopy (MIS) technique is introduced to overcome the weaknesses of the previous approaches. MIS method implements phase shift measurements. This technique is capable of measuring phase angle between primary signal and the secondary signal. The secondary signal comes from eddy current generated by the object under investigation. A 3D model of MIS system for jaundice measurement consisted of transmitter, receiver and baby finger was designed and simulated using COMSOL Multiphysics 5.0.The transmitter and receiver were modelled using circular coil (copper wire) with 1 mm diameter and simulated at different operating frequencies under beta dispersion region which are 2 MHz, 4 MHz, 6 MHz, 8 MHz and 10 MHz. To experimentally evaluate the performance of the MIS system, five sample solution to mimic bilirubin concentrations (85.0 μmole/L, 170.0 μmole/L, 255.0 μmole/L, 290.0 μmole/L and 331.5 μmole/L) were tested using MIS circuit. In this research, two pairs of transmitter and receiver (Tx-Rx) which only differ at receiver size were tested; Tx5-Rx8 and Tx5-Rx12. The results have shown that Tx5-Rx8 has less sensitivity to detect phase shift compared to Tx5-Rx12. This is due to the greater gradient value of Tx5-Rx12 with 0.0594 relative to Tx5-Rx8 which is 0.0584. Through this research study, it is proven that higher frequency gives higher phase shift where our MIS system recorded that at 10 MHz, phase shift increased from 0.2758 to 0.3004 degree when the electrical conductivity of five samples solution increased. This contributes to an easy calculation of phase difference between primary field and the secondary field. This study shows that MIS system has the potential to detect jaundice in newborn infants through non-invasive method
