Now showing 1 - 10 of 13
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Enhancement of non-permutation binomial power functions to construct cryptographically strong S-Boxes

2023 , Herman Isa , Syed Alwee Aljunid Syed Junid , Muhammad Reza Z’aba , Rosdisham Endut , Syed Mohammad Ammar , Norshamsuri Ali @ Hasim

A Substitution box (S-box) is an important component used in symmetric key cryptosystems to satisfy Shannon’s property on confusion. As the only nonlinear operation, the S-box must be cryptographically strong to thwart any cryptanalysis tools on cryptosystems. Generally, the S-boxes can be constructed using any of the following approaches: the random search approach, heuristic/evolutionary approach or mathematical approach. However, the current S-box construction has some drawbacks, such as low cryptographic properties for the random search approach and the fact that it is hard to develop mathematical functions that can be used to construct a cryptographically strong S-box. In this paper, we explore the non-permutation function that was generated from the binomial operation of the power function to construct a cryptographically strong S-box. By adopting the method called the Redundancy Removal Algorithm, we propose some enhancement in the algorithm such that the desired result can be obtained. The analytical results of our experiment indicate that all criteria such as bijective, nonlinearity, differential uniformity, algebraic degree and linear approximation are found to hold in the obtained S-boxes. Our proposed S-box also surpassed several bijective S-boxes available in the literature in terms of cryptographic properties.

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Effects of applied magnetic field on the optical properties and binding energies spherical GaAs quantum dot with donor impurity

2022 , Collins Okon Edet , Emre Bahadir Al , Fatih Ungan , Norshamsuri Ali @ Hasim , Nursalasawati Rusli , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Muhammad Asjad

The screened modified Kratzer potential (SMKP) model is utilized to scrutinize the impacts of an applied magnetic field (MF) on the binding energies and linear and nonlinear optical properties spherical GaAs quantum dot with donor impurity (DI). To accomplish this goal, we have used the diagonalization method to numerically solve the Schrödinger equation under the effective mass approximation for obtaining the electron energy levels and related electronic wave functions. The expressions used for evaluating linear, third-order nonlinear, and total optical absorption coefficients and relative refractive index changes were previously derived within the compact density matrix method. It has been shown here that the MF and DI impacts the characteristics of the absorption coefficients and the refractive index changes. This study’s results will find application in optoelectronics and related areas.

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Impact of rain attenuation in Borneo using free space optics propagation

2021-12 , Tauffiq Khirham , AK Rahman , Sahari S.K , Zamhari N , Tamrin F.K , Syed Alwee Aljunid Syed Junid , N. Ali , Rosdisham Endut

In recent years, Free Space Optics (FSO) communication provides attractive bandwidth enhancement with unlicensed bands worldwide spectrum. However, the link capacity and availability are the major concern in the different atmospheric conditions. The reliability of the link is highly dependent on weather conditions that attenuate the signal strength. In the tropical region specifically in Borneo Sarawak, rain is the dominant weather that act as the limiting factor to FSO performance. Hence, this study highlights on the impact of rain attenuation to the performance of FSO communication system. The finding is based on atmospheric model and performed through the simulation of OptiSystem software. The design of parameters in the simulation involves iteration of wavelengths, size of transmitter and receiver aperture and beam divergence angle. The simulation result shows longer wavelength 1550nm is much better than 785nm. The 0.25m of receiver aperture and transmitter aperture at 0.05m can reduce the loss. Narrow beam divergence angle can reduce the power consumption and maintain the high power at receiver. The analysis indicates that proposed FSO communication system is capable to withstand the attenuation from rain weather.

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Two dimensional (2D) OCDMA encoder-decoder for various industrial application

2021-12 , Syed Alwee Aljunid Syed Junid , Mohd Arif Anuar Mohd Salleh , A A M Ismail , ND Keraf , R Matem , Mohd Rashidi Che Beson , Norshamsuri Ali @ Hasim , Mohd Shafiq Amirul , Rosdisham Endut , Nor Azura Malini Ahmad Hambali

Future telecommunication systems and networks are expected to provide a variety of integrated broadband services to the customers. There has been a tremendous interest in applying Code Division Multiple Access (CDMA) techniques to fiber optic communication systems. This technique is one of the multiple access schemes that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty networks. This project is focusing on designing 2D OCDMA system with the hardware implementation of design using FPGA. The coding techniques in OCDMA are time versus wavelength and amplitude versus phase. 2D OCDMA coding incorporates both wavelength selection and time distribution. The data bit would be encoded as consecutive chips with various wavelengths. The code architecture seeks to produce codes with high autocorrelation and low cross-correlation properties. Code length is an essential aspect of code and device architecture for coding characteristics. The hardware implementation of the system is designed by using FPGA De1-SoC. The FPGA have the abilities to enhance the transmission of data to the receiver in a short period of time. The performance of 2D OCDMA system is expected to surpass 1D OCDMA system in terms of BER and the number of simultaneous users that can be supported. The system encoder and decoder were designed using optical switch, splitter, combiner and modulator. The performance of 2D OCDMA system in terms of time spreading and wavelength spreading is also compared which shown a huge difference in the results. The best performance of the system is when the number of wavelength (M) is fixed to 18 and the number of times spreading (N) is 31 which can support 350 more simultaneous users.

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Development of new spectral amplitude coding OCDMA code by using polarization encoding technique

2023 , Syed Mohammad Ammar , Norshamsuri Ali @ Hasim , Mohamad Naufal Saad , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Ahmed M. Alhassan , Collins Okon Edet

OCDMA is an optical access technology that has a lot of potential because it can be asynchronously accessed and provides a higher level of security. The authors presented a new DW family code, a flexible double weight (FDW) code, and a novel polarization encoding approach in this paper. The new code is applicable to both odd- and even-weighted codes. The novel polarization encoding approach may be used for numerous wavelengths that overlap. Based on analytic principles, a comparison of two widely used spectrum amplitude-coding SAC-based OCDMA codes, notably modified frequency hopping (MFH), Hadamard, and the double weight (DW) code family. The comparison was based on observing the bit error rate (BER) in each situation. The DW code has a fixed weight of two. The FDW code was introduced to reduce phase-induced intensity noise and multiple access interference (MAI) in transmission networks. FDW codes are versions of the DW code family with weights larger than two. The FDW code outperforms the Hadamard, MFH, DW, modified double weight (MDW), and enhanced double weight (EDW) algorithms. FDW has the capacity to support up to 220 concurrent users. With the new polarization encoding technology, the FDW code can travel up to 60 km at a bit rate of 2.5 Gb/s and 40 km for a 10 Gb/s bit rate.

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Non-Relativistic energy spectra of the modified Hylleraas potential and its thermodynamic properties in arbitrary dimensions

2022 , Collins Okon Edet , Jonathan E. Osang , Norshamsuri Ali @ Hasim , Emmanuel Paul Agbo , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Emmanuel B. Ettah , Reza Khordad , Akpan Ndem Ikot , Muhammad Asjad

n this study, the solutions of the Schrodinger equation (SE) with modified Hylleraas potential in arbitrary dimensions was obtained using the asymptotic iteration method (AIM) to obtain the energy and wave functions, respectively. The energy equation was used to obtain the thermal properties of this system. The effect of the potential parameters and dimensions on the energy spectra and thermal properties was scrutinized thoroughly. It was found that the aforementioned affects the thermal properties and energy spectra, respectively. In addition, we also computed the numerical energy spectra of the MHP for the first time and discussed it in detail. The results of our study can be applied to molecular physics, chemical physics, etc.

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Performance analysis of double-MIMO free space optical system under atmospheric turbulence

2021-12 , A L Tom , A K Rahman , Tamrin F K , Sahari S K , Zamhari N , Syed Alwee Aljunid Syed Junid , Norshamsuri Ali @ Hasim , Rosdisham Endut

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.

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Performance analysis of coherent source SAC OCDMA in free space optical communication systems

2023 , Ahmed M. Alhassan , Eithar Issam , Syed Alwee Aljunid Syed Junid , Mohd Rashidi Che Beson , Syed Mohammad Ammar , Norshamsuri Ali @ Hasim , Rosdisham Endut

In this paper, we investigate the performance of spectral amplitude coding optical code division multiple access (SAC OCDMA) systems under the effect of beat noise and turbulence. Three different multi-laser source configurations are considered in this analysis: shared multi-laser, separate multi-laser, and carefully controlled center frequency separate multi-laser. We demonstrate through Monte Carlo simulation that the gamma–gamma probability density function (pdf) cannot adequately approximate the measured intensity of overlapping lasers and that an empirical pdf is required. Results also show it is possible to achieve error-free transmission at a symmetrical data rate of 10 Gbps for all active users when only beat noise is taken into account by precisely controlling the center frequencies. However, only 30% of the active users can be supported when both beat noise and turbulence are considered.

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Global quantum information-theoretic measures in the presence of magnetic and Aharanov-Bohm (AB) fields

2022 , Collins Okon Edet , Emmanuel Benjamin Ettah , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Norshamsuri Ali @ Hasim , Akpan Ndem Ikot , Muhammad Asjad

The global quantum information-theoretical analysis of the class of Yukawa potential (CYP) in the presence of magnetic and Aharonov–Bohm (AB) fields has been examined both analytically and numerically in this research piece. The energy equation and wave function for the CYP are obtained by solving the Schrodinger equation in the presence of external magnetic and AB fields using the functional analysis technique. The probability density is used to calculate the Tsallis, Rényi, and Onicescu information energy entropies numerically. The influence of the screening parameter (β), magnetic (B→), and AB (ξ) fields on the global information-theoretical measurements for the CYP is explored. Atomic and molecular physics, quantum chemistry, and physics are specific areas where these research findings will find application.

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Prediction model for spectroscopy using python programming

2021-12 , A A M Ismail , Norshamsuri Ali @ Hasim , Mohd Shafiq Amirul , Rosdisham Endut , Syed Alwee Aljunid Syed Junid

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.