Now showing 1 - 10 of 35
  • Publication
    Enhancement receiver sensitivity under heavy attenuation effect for FSO system via double transmission technique
    This paper focus on improvement of receiver sensitivity for free space optical communication. FSO communication is frequently drop performance when facing bad weather. In this research proposed new development of transmitter and receiver design in order to reduce the impact of atmospheric attenuation and increase receiver sensitivity. The analysis performance will compare with conventional amplitude shift keying (ASK) approach. Simulation result will be used to measure the performance and comparison between conventional and new proposed modulation double transmission balance receiver (DTBR) will also presented. The measurement of result will involve the effect of geometrical loss, data bit rate and distance propagation. From the result, the DTBR is increase the receiver sensitivity in term of bit error rate (BER) performance.
  • Publication
    Characteristics of multiwavelength fiber laser employing semiconductor optical amplifier in nonlinear optical loop mirror with different length polarization maintaining fiber
    In this paper, we propose and demonstrate generated characteristics of a multiwavelength fiber laser based on semiconductor optical amplifier in a nonlinear optical loop mirror with different length of polarization maintaining fiber. The configuration comprises 3-dB optical coupler, semiconductor optical amplifier and, 2 meters and 10 meters of polarization maintaining fiber. Characteristics of multiwavelength fiber laser are studied through the use of polarization maintaining fiber at different lengths. The experimental results revealed the number of lasing lines increases with the increment of the polarization maintaining fiber length. The polarization maintaining fiber with 10 meters of length has the ability to generate a higher number of lasing lines up to 47 signals with semiconductor optical amplifier injected current at 180mA, respectively. However, in terms of average peak power and average optical signal to noise ratio, the 2 meter of polarization maintaining fiber length has the capability to produce a higher value which is 0.45mW at 250mA of semiconductor optical amplifier driven current and 28.86dB at 170mA of semiconductor optical amplifier driven current, respectively. Furthermore, it is observable that this configuration capable to generate a wider bandwidth which is operating in the conventional (C) band to long (L) band at the room temperature.
  • Publication
    Performance analysis of double-MIMO free space optical system under atmospheric turbulence
    ( 2021-12)
    A L Tom
    ;
    A K Rahman
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    Tamrin F K
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    Sahari S K
    ;
    Zamhari N
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    ; ;
    Over the last few years, free space optical communication (FSO) has emerged as a viable alternative to radio frequency communication. It provides a promising high-speed point-to-point communication solution. However, atmospheric absorption, scattering and turbulence degrade wireless optical communication significantly, lowering device efficiency. The attenuation of signals due to the above atmospheric reasons is another major factor that affects device efficiency. The atmospheric turbulence conditions are observed implemented into different models of FSO systems, such as Single Input Single Output (SISO), Multiple Input Multiple Output (MIMO), Wavelength Division Multiplexing MIMO (WDM-MIMO) and proposed model Double Multiple Input Multiple Output (DMIMO) using the Gamma-Gamma model for a variety of reasons. The OptiSystem 7.0 software was used to run simulations to study how various weather conditions (clear, haze and fog) affected the performance of the channel. Simulation results show that implementing Double Multiple Input Multiple Output (DMIMO) techniques for FSO systems provides high quality factor for various ranges while still achieving accurate transmitted data at the receiver side. In the presence of atmospheric turbulence conditions such as clear air, haze and fog, performance improvements signal power levels, quality factor and link distance range have been demonstrated.
  • Publication
    Nitrate (NO3-) prediction in soil analysis using near-infrared (NIR) spectroscopy
    ( 2020-01-08)
    Sabri, Mohd Shafiq Amirul
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    ; ; ; ;
    Laili M.H.
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    Laili A.R.
    ;
    Ismail M.N.M.
    Nutrient composition in soil analysis is investigated by using nitrogen (N) in form of nitrate (NO3-) as a representative factor correlated with NIR spectroscopy spectral absorbance. NIR spectroscopy method of sampling has been tested to overcome time consuming, complex chemical analysis procedure and invasive sampling method in order to identify nitrate content in soil samples. Spectral absorbance data from range 950 nm to 1650 nm correlated with nitrate reading then tested through few pre-processing techniques. Five techniques have been listed as top performer, which are Multiplicative Scatter Correction using Common Offset (MSCCO), Multiplicative Scatter Correction (MSC), Range Normalization (RN), Mean Normalization (MN) and Reduced (R) technique. Data calibration and prediction of both data is evaluated using Partial Least Square Regression (PLSR) model. In the final analysis, R technique has achieved as top performer pre-processing technique for both calibration and prediction results, with the coefficient of determination (R2) values of 0.9991 and root mean square error (RMSE) values of 0.0886 for prediction. Overall, the correlation of NIRS absorbance data and nitrate can be obtained using PLSR model with R pre-processing technique. Henceforth, we can conclude that the NIRS method of sampling can be used to identify nitrate content in soil analysis by using time saving, non-invasive and less laborious method of sampling.
  • Publication
    Prediction rain attenuation effect on free space optical communication Kuching/Samarahan Region
    Rain attenuation is significantly affecting the FSO performance of a free-space optical communication system. Kuching/Samarahan region is situated in Malaysia state which is under tropical climate zone. The rain distribution is recorded high due to having rain season year-round. It worst when turn to monsoon season where the precipitation rate is expected high and dense. It is crucial to design the effect FSO system to ensure good quality transmission beam signal. This paper is focus on Kuching/Samarahan zone as the preliminary result to investigate the rain pattern and effect over FSO propagation. The investigation it focuses on that region is due to development that area to implement fully digital economy which need supported by high speed and capacity data that can be produced by optical technology. Therefore, FSO technology can perform this task. The rain data is collected from Malaysia Meteorology Department (Met Malaysia) which for three years 2017, 1018 and 2019. The performance will measure the effect of scattering coefficient, rain attenuation and geometrical loss. It is expected heavy rain will contribute the great impact over FSO link.
  • Publication
    Prediction model for spectroscopy using python programming
    ( 2021-12)
    A A M Ismail
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    ;
    Mohd Shafiq Amirul
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    This paper is motivated by searching for the perfect pattern for the spectroscopy spectra using artificial neural networks (ANN) using python programming coding. The pattern from the spectroscopy is based on the absorption and emission of light and other radiation by materials in relation to the wavelength dependence of these processes. Spectral equipment such as spectrometers, spectral analysers, spectrographs, or spectrophotometers is utilised to determine spectrum values. The problem in this spectroscopy is to identify the sample or analyte, which can be solved by a prediction model for spectroscopy using Python. These problems occur when finding the best algorithm of pre-processing techniques that can predict any model accurately into an understandable format for prediction models. Various types of pre-processing techniques have been used, such as Multiplicative Scatter Correction (MSC), Inverse MSC, Extended MSC (EMSC), Extended Inverse MSC, de-trending, Standard Normal Variate (SNV) and normalisation in order to get a better r2 value. In this project, we find the r2 and the root mean square error (RMSE) to evaluate the prediction values and the actual values. First, choosing pre-processing techniques and then finding the best statistical method for constructing predictive models that produce high accuracy. We used ANN in this project as a prediction model. Based on the results, we managed to achieve our objective, which is that the prediction model has more than 90% of accuracy. Furthermore, the results show that our prediction model has 1.0 accuracy at 100 Epoch with a 0.3 learning rate. Finally, we can conclude that our prediction model can be used to predict the spectroscopy-based data format.
  • Publication
    Smart embedded-analytics sensors with cloud-based measurement system for HVAC
    HVAC system is a necessary component of environment to maintain the temperature and humidity to be kept at certain levels by using air taken from outside to ensure the indoor comfort. The purpose of the study is to reduce the electricity energy usage and cost from air conditioning by using smart embedded-analytics sensors to provide the automatic thermal control in an area. In this study, we used sensors such as temperature and humidity sensors to detect and read the currently temperature and humidity of an area monitored by a microcontroller. The cloud-based system and the sensors are connected via wifi in the presence of MQTT protocol. The protocol enables publish and subscribe method which provide the communication between sensors, cloud-based system and HVAC system. This communication can serve thermal control automatically thus resulting the optimize usage of energy from air conditioning according to the external environment temperature and humidity. The control of the temperature and humidity from air conditioning can be designed through the programming embedded in the microcontroller. The monitoring result can be displayed from the control panel to ensure how the system works.
  • Publication
    Thermal properties and mass spectra of heavy mesons in the presence of a Point-Like defect
    ( 2024)
    Etido P. Inyang
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    ; ; ; ;
    N.R. Ali
    ;
    Muhammad Muhammad Asjad
    In this research, the radial Schr¨odinger equation is solved analytically using the Nikiforov-Uvarov method with the Cornell potential. The energy spectrum and the corresponding wave function are obtained in close form. The effect of Topological Defect on the thermal properties and mass spectra of heavy mesons such as charmonium and bottomonium are studied with the obtained energy spectrum. It is found that the presence of the Topological Defect increases the mass spectra and moves the values close to the experimental data. Our results agreed with the experimental data and are seen to be improved when compared with other works.