Institute of Engineering Mathematics (IMK) (Theses)
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/41148
2024-03-29T15:07:35ZDetection of outliers in multiple circular regression model
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/79012
Detection of outliers in multiple circular regression model
The multiple circular regression model (MCRM) describe the relationship between two
or more circular variables. This model has many interesting properties and is sensitive
enough to detect the occurrence of any outliers. However, no related studies have been
found on outliers’ detection for more than one independent circular variable, which for
MCRM. The aim here is to develop an outlier detection procedure in MCRM and how it
unexplored problems related to this model. Firstly, is to examine the robustness of this
model towards outliers. Secondly, five statistics of identifying outliers in the model are
proposed, in which two of the proposals are from linear case to circular case i.e the
DFBETAc statistic and the DFFITc statistic, and three of the proposals are extended from
the single circular case to multiple circular cases i.e the COVRATIOc statistic, DMCEc
and DMCEs statistics. A simulation study was done to identify the cut-off points through
row deletion approach and the power performances of all five statistics were determined.
Finally, all these proposed statistics were applied to the real data and the statistics were
compared. Results of simulation studies shows that the proposed of five statistics perform
well in detecting outliers in MCRM.
Doctor of Philosophy in Statistics
Design optimization of the interior vehicle noise and vibration through computational approaches
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/78356
Design optimization of the interior vehicle noise and vibration through computational approaches
Noise and vibration performance is an indispensable criterion in vehicle design and validation processes since it significantly affects the marketing image of automotive vehicles. The primary goal of this study is to assess and optimize the acoustic and vibration levels in the interior vehicle cabin. The study demonstrated experimental design to acquire sound and vibration signals using three local compact Perodua cars namely Axia, Myvi and Viva on idle (stationary) and non-stationary (highway, pavement and urban) driving conditions. The measured sounds and vibrations are analyzed to obtain the sound quality and vibration exposure levels in the interior cabin. Apart from this, the study presents a formulation of Noise Isolation Index (NII) based on categorizing the trends of sound quality into interior and exterior noises. The NII is developed, compared and validated for the three tested cars and the results showed that Axia has the highest comfort and thus optimal isolation criterion toward the exterior noises. Besides conducting clustering to compare the interior comfort of Axia, Myvi and Viva, this study developed Genetic Algorithm to further optimize the noise and vibration in the interior vehicle cabin. The results of GA model revealed that the interior noise is influenced by vibration exposure values in the interior vehicle cabin. Overall findings of this study indicate that the comfort level is factually influenced by factors including type of road surface, engine transmissions and vehicle design characteristics.
Master of Science in Engineering Mathematics
A comparative study on whole body vibration (WBV) comfort towards Perodua's compact car model through Monte Carlo simulation
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/78354
A comparative study on whole body vibration (WBV) comfort towards Perodua's compact car model through Monte Carlo simulation
The objective of this research is to study the vibration which generate in the cabin of the car and seek for the vibration comfort level between all three cars to compare car which has a finest level of comfort between this three cars. In this study, the level of vibration in the cabin of the three car engine speed as measured by car respectively. Vibration generated during experiments in the cabin cars is recorded and stored in the form's data and the test in two circumstances, namely, state of stationary and is not stationary. When in a situation not stationary vibration resulting in the car taken during guided through three types of road namely highway, pavement and urban. A programming system developed to record the generation of vibration in the cabin of the car. Data collected that have been collected will be go through some process start with methods evaluation vibration and regression analysis. An equation will be approach through the analysis to find the significant data that can be used in the process which is K-Means algorithm. Based on the trends of the experienced and exposed vibration, the model is able to differentiate the level of comfort between the clusters by grouping the level of sound vibration into five categories which are most pleasant, medium pleasant, marginal, medium annoying and most annoying. To review the accuracy of classification data cluster, the K-Nearest Neighbor method and Linear Discriminant Analysis is used for shows the percentage accuracy of classification data have been cluster. Later, the vibration for the three cars in this study which has analyzed, compared using the approach of analysis of variance (ANOVA).
Master of Science in Engineering Mathematics
Application of cubic timmer curve with countinuity on batik design
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/78210
Application of cubic timmer curve with countinuity on batik design
In the world of CAGD, to create curve the research tends to use the curve that been usually used such as B-Spline and Bezier. Apparently, the researcher tends to choose cubic curve because it is easier to generate in coding that been created. In this study, Cubic Timmer curve that been chosen to create the curve based on chosen example which is a sample of Batik Design because advantages of Cubic Timmer curve is it tend to go through the midpoint of control polygon that brings a lot of help in creating the curve. Cubic Timmer curves that been created had C0 or C1 continuity by using Mathematica and MATLAB
software. After a sample of Batik design is chosen, the sample been inserted into
Mathematica then control points are selected. The control points that been selected are
insert into coding in MATLAB then been generated to have a curve. Among the curves
that been generated, the control point must be adjusted to make the curve having 1 C
continuity if the curves are not to be connected by 1 C continuity then it is 0 C continuity.
If the curve that been generated is not fulfilled the curve that desired then the control points
must be altered to have a good resemble curve as sample. The result is mimicking the
sample of Batik design perfectly since of its uniqueness properties that help a lot in
creating the curve.
Master of Science in Engineerng Mathematics