Ameruddin Baharom

Study of Underwater Channel Estimation Based on Different Node Placement in Shallow Water

Acoustic underwater sensor network (UWSN) is important in terms of business and for military applications. Optimum UWSN design provides a reliable connection with maximum connectivity, minimal multipath, low technical cost, and emphasis on energy conservation. This paper examines the channel estimation parameters, such as channel impulse response, coherence bandwidth, BER due to delay for differentially detected MSK receiver, and transmission loss impact of underwater node placement in three scenarios (ground-based, buoys-based, and horizontal point-to-point sensor node). All data (bathymetry, altimetry, temperature, salinity, and depth) are real and have been sourced from different satellite databases. The case study of this paper is the Desaru beach in the eastern shore of Johor Bahru in Malaysia. In this investigation, Acoustics Toolbox of BELLHOP through MATLAB and mathematical analyzing method has been utilized. As a result, this paper indicates the maximum received power, and the lowest delay time characteristics and TL belong to horizontal point-to-point scenario; moreover, the ground-based scenario has the highest delay time and maximum coherence bandwidth among three scenarios.

PID controller tuning by particle swarm optimization on electrical discharge machining servo control system

Electrical Discharge Machining (EDM) is included in a stochastic process. So maintaining gap between electrode and workpiece is not easy. In order to control the gap, a proportional integral derivative (PID) controller is designed for EDM servo actuator system. The main goal of this work is to get PID parameters through Particle Swarm Optimization (PSO) algorithm to ensure a stable, robust and controlled system. The controller and the model for EDM die sinking are verified by simulation of the control system using MATLAB and simulink program. Simulation results verify the effectiveness of the PID controller in which its parameter determined by PSO to control the electrode position towards workpiece.

Evaluation of underwater acoustical intermittent ambient noise

This paper focused on the analysis of underwater intermittent biological noises produced by dolphin, shrimp, seahorse, bubble samples. We analyzed the noise frequency spectrum and calculate sound level pressure for every sample in its frequency distribution. Using stationary test, signal changes in the interval of 0.1 second is observed. Assuming Gaussian distribution, normality trial is investigated. Simulations and examinations are done using MATLAB programs in order to illustrate signal noise behavior to optimize filtering and detection purpose. From this study, all samples exhibit stationary and normality distribution properties, in addition the bubble and shrimp have a higher sound pressure level compare to other samples.

Month-to-month variability of the melting layer boundaries

The Bright-band is the typical enhancement in radar reflectivity during the melting process, which is still not completely determined. The seasonal variation over the year can give the characteristics that are valuable for designing and planning of a satellite link. The Malaysian meteorological radar data, from Kluang radar station (Johor), is used to trace the signature of the melting layer during stratiform precipitations events. The trends of the boundaries of the melting layer were studied by considering data extended to cover a six-month period (January-June 1998). It was observed that the boundaries and the thickness of the melting layer are found to be seasonally dependent.

Erosion rate model comparison of Electrical Discharge Machining process

This paper reports a comparison studies between two erosion rate model and experimental results of an Electrical Discharge Machining (EDM) process for high gap current. Two erosion rate models are Dimensional Analysis (DA) model and Artificial Neural Network (ANN) model that have been summarized from the previous authors publication. The data analysis is based on a copper electrode and steel workpiece materials. The result indicated that the ANN model provides better accuracy than the DA model when compared to the experimental results.

Characterization of sound speed profile in Malaysian Sea off Tanjung Balau

Underwater communications exists in many applications, providing information about the ocean floor such as bathymetry, for environmental pollution monitoring, information exchange between divers and sea vessel, and collection of scientific data. However, the propagation of sound in the sea is dependent on several environmental factors such as pressure which is related to depth, and some other ocean properties. The characteristic of sound propagation in the sea is determined by what is known as the sound speed profile. The speed of sound in the sea is determined and varies with depth, salinity change, temperature, the season as well as the geographic location. In general, different sea conditions has different characteristics of the sound speed profile. This project was aimed to determine the sound speed profile in Malaysian Seas. Parameters, which affect the sound speed profile, were studied, and their values determined.

Investigation of workpiece positioning methods for machining oil-pocket on hip-implant spherical surface

Oil pocket has been reported that it may improve tribology characteristic and thus prolong the lifespan of the joint. In order to implement it on spherical surface, appropriate positioning system is required. This paper reports the investigation of three axes workpiece positioning system in order to machine oil pocket (micro-pits) on hip implant. A conventional linear x-y-z axes configuration (Cartesian coordinate) and two configuration of spherical coordinate (swing-swing and swing-rotate configuration) are applied in simulation. All machined workpiece are investigated in pits distribution, shape, and machined angle. The inspection concludes that spherical method with swing-rotate configuration is the most suitable method for machining oil pocket on spherical surface.

PID Controller Tuning by Differential Evolution Algorithm on EDM Servo Control System

Maintaining gap between Electrode and workpiece in Electrical Discharge Machining (EDM) is very important since the capability of control system to keep the gap will improve the performance of this machine. Therefore to maintain the gap, a Proportional Integral Derivative (PID) controller is designed and applied to EDM servo actuator system. The objective of this work is to obtain a stable, robust and controlled system by tuning the PID controller using Differential Evolution (DE) algorithm. The controller for EDM die sinking is verified by simulation of the control system using MATLAB/Simulink program. Simulation results verify the capabilities and effectiveness of the DE algorithm to search the best configuration of PID parameters controller to control the electrode position.