Optical Fiber Bending Detection on Long Distance OPGW using OTDR

In Malaysia, thousands of kilometers of Optical Ground Wire (OPGW) have been installed by a utility company. For long distance fiber cable, there is a possibility of optical fiber to bend with very small radius especially in joint closures which caused optical power to attenuate. This attenuation is known as ‘bend losses. Bend loss increases the total power attenuation of optical fiber. In addition, for long distance fiber cable, it is important to avoid any extra loss as the fiber itself attenuates 0.2 to 0.35 dB/km and splice loss about 0.1 dB each. Hence, in this study, the method of detecting bend loss as well as optical fiber bending is presented. The result of this study is expected to allow fiber industry players to determine the exact location and proper rectification can be done to solve bend loss problem

Multi slot amplitude coding technique for high speed optical fiber communication system

The rapid progress of the high speed optical communications system is driven by the exponential growth of users demand on information and services. The trend towards high speed and high capacity transmission system are multiplexing technique such as electrical time division multiplexing (ETDM) and duty cycle division multiplexing (DCDM). Unfortunately, ETDM bit rate is limited by the speed of electronic devices and DCDM suffers from increased spectral width when the number of tributary increased. Therefore, in this research, a new multiplexing technique is proposed, known as Multi Slot Amplitude Coding (MSAC). In this technique, three, four and five tributaries can be achieved with less number of slots compared to DCDM. The performance of 310 Gbit/s MSAC is -26 dBm for receiver sensitivity (RS) and 25.5 dB for optical signal-to-noise ratio (OSNR). The improvement of 3.5 dB for RS and 3.7 dB for OSNR are obtained when optimize level spacing is implemented. When compared to DCDM, the spectral width is reduced by around 25%, not less than 55% improvement of chromatic dispersion (CD) tolerance, 0.6 dB better RS, and 1.5 dB better OSNR. The spectral width for 310 Gbit/s, 410 Gbit/s and 510 Gbit/s MSAC is 60 GHz, which indicates improvement of spectral efficiency. Optical spectrum of MSAC has spectral line at 10 GHz to provide an accurate clock frequency at symbol rate. In addition the performance of MSAC technique is simulated under self phase modulation (SPM) effect. The result shows that the maximum launched optical power is +12.79 dBm and +12.62 dBm for 50 km and 80 km standard single mode fiber (SSMF) with 100% compensation of dispersion using dispersion compensation fiber (DCF) at receiver. Moreover, SPM threshold improves around 2.7 dB when adopting the pre and post dispersion compensation method

Nonlinear Dynamics of Chaotic Attractor of Chua Circuit and Its Application for Secure Communication

The Chua circuit is among the simplest non-linear circuits that shows most complex dynamical behavior, including chaos which exhibits a variety of bifurcation phenomena and attractors. In this paper, Chua attractor's chaotic oscillator, synchronization and masking communication circuits were designed and simulated. The electronic circuit oscilloscope outputs of the realized Chua system is also presented. Simulation and oscilloscope outputs are used to illustrate the accuracy of the designed and realized Chua chaotic oscillator circuits. The Chua system is addressed suitable for chaotic synchronization circuits and chaotic masking communication circuits using Matlab® and MultiSIM® software. Simulation results are used to visualize and illustrate the effectiveness of Chua chaotic system in synchronization and application of secure communication.  Keywords: chua nonlinear circuit, chaotic attractor, chaotic synchronization, secure communication

Comparative study ofthe computational fluid dynamics and fluid structure interaction analysis in human airways flow

Numerous studies have been done in order to get the most accurate result that represents the flow characteristics inside the human trachea. Numerical method was the most favorite type of study chosen to simulate the model due to the complexity of the geometry and difficulties to get the real trachea to do the experimental works. In this study, one actual healthy model of human trachea was reconstructed in order to compare, the different of the velocity and pressure distribution between two types of numerical modeling analysis: Computational Fluid Dynamics (CFD) and Fluid Structure Interaction (FSI) analysis. The model was extracted using the Computed Tomography (CT) scan images to maintain the realistic geometry. Velocity, 1.24 m/s was used at the inlet and the variations of the velocity and pressure distribution along the trachea were observed. The results shown that, the implementation of the FSI technique did produce different result and flexibility of the structure wall did influence the distribution of the velocity and pressure along the trachea

MEDIA OPTIMIZATION FOR BIOPROTEINS PRODUCTION FROM CHEAPER CARBON SOURCE

There are high demands for animal and human food supply especially protein, which is an important dietary component. Agricultural wastes, cheap carbon sources- which are rich and have high energy, can be used for producing the value added bioprotein. A lab scale study was carried out to optimize the media composition for bioprotein production from a cheaper carbon source - wheat flour using potential strain, which was selected earlier by screening different microorganisms. The performance of the selected strain was enhanced by media optimization with varied substrate concentration, nitrogen sources and nutrient supplementation according to the central composite design from STATISTICA software. Statistical optimization was carried out to evaluate the polynomial regression model through effect of linear, quadratic and interaction of the factors. The maximum biomass produced was 21.89 g/L with optimum fermentation conditions of wheat flour (4 g/L), nitrogen concentration (0.5 g/L), nutrient concentration (0.1 g/L), and four days of fermentation

Factors affecting endoglucanase production by Trichoderma reesei RUT C-30 from solid state fermentation of oil palm empty fruit bunches using Plackett-Burman design

A study was conducted to screen parameters affecting the production of endoglucanase by Trichoderma reesei RUT C-30 on solid state fermentation of oil palm empty fruit bunch using the Plackett-Burman design. Factors involved in the screening process were peptone concentration, urea concentration, ammonium sulfate concentration, calcium nitrate concentration, yeast extract concentration, tween 80 concentration, pH, incubation time, initial moisture content, inoculum size and substrate amount. Through analysis of variance (ANOVA), it was found that initial moisture content (p= 0.001), incubation time (p= 0.001), inoculum size (p= 0.032) and ammonium sulfate concentration (p= 0.023) have been recognized as significant factors affecting endoglucanase activity in solid state fermentation (SSF) of oil palm empty fruit bunch (OPEFB) by T. reesei RUT C-30. The model established from the ANOVA analysis have a significant value of Pmodel>F= 0.0008 and R2 of 0.9132. The preoptimized media showed 2.6 fold increased of endoglucanase activity.Key words: Cellulase, oil palm empty fruit bunches, solid state fermentation, Trichoderma reesei RUT C-30, Plackett-Burman design

Autocorrelated process control: Geometric Brownian Motion approach versus Box-Jenkins approach

Existing of autocorrelation will bring a significant effect on the performance and accuracy of process control if the problem does not handle carefully. When dealing with autocorrelated process, Box-Jenkins method will be preferred because of the popularity. However, the computation of Box-Jenkins method is too complicated and challenging which cause of time-consuming. Therefore, an alternative method which known as Geometric Brownian Motion (GBM) is introduced to monitor the autocorrelated process. One real case of furnace temperature data is conducted to compare the performance of Box-Jenkins and GBM methods in monitoring autocorrelation process. Both methods give the same results in terms of model accuracy and monitoring process control. Yet, GBM is superior compared to Box-Jenkins method due to its simplicity and practically with shorter computational time

Mamdani-Fuzzy Modeling Approach for Quality Prediction of Non-Linear Laser Lathing Process

Lathing is a process to fashioning stock materials into desired cylindrical shapes which usually performed by traditional lathe machine. But, the recent rapid advancements in engineering materials and precision demand gives a great challenge to the traditional method. The main drawback of conventional lathe is its mechanical contact which brings to the undesirable tool wear, heat affected zone, finishing, and dimensional accuracy especially taper quality in machining of stock with high length to diameter ratio. Therefore, a novel approach has been devised to investigate in transforming a 2D flatbed CO2 laser cutting machine into 3D laser lathing capability as an alternative solution. Three significant design parameters were selected for this experiment, namely cutting speed, spinning speed, and depth of cut. Total of 24 experiments were performed with eight (8) sequential runs where they were then replicated three (3) times. The experimental results were then used to establish Mamdani - Fuzzy predictive model where it yields the accuracy of more than 95%. Thus, the proposed Mamdani-Fuzzy modeling approach is found very much suitable and practical for quality prediction of non-linear laser lathing process for cylindrical stocks of 10mm diameter

Implementation of cryptography algorithms in SCADAKratos application

This paper studies cryptography algorithms to be implemented into the SCADAKratos application of thermal vacuum chamber (TVC) system. SCADAKratos application is used to control and monitor the operations of the TVC which is a satellite test equipment that is located at the Malaysia Space Centre, Banting, Malaysia. The security features had been put aside during the development as it was claimed that there is no threat to the system since the system is operated internally. However, during service and troubleshooting by the manufacturer, the system will be accessed through public network. Besides that, the system also can be accessed remotely during operation for control and monitoring purpose. In addition, the testing data results also need to be transferred to the customer through the internet as it is easier and faster. The remote access through public network will cause the TVC system to face a risk to any threat and attack. Therefore, the implementation of cryptography algorithm into TVC system is needed in order to secure and protect the system from unauthorized access. This paper explains the architecture of SCADAKratos application of TVC system and how the cryptography algorithms could be implemented through this application. Secure Hash Algorithm (SHA-1) and AES algorithm (AES) are chosen as the encryption technique which will be applied in the TVC system. Simulation result shows that this technique is feasible for the mentioned implementation

Semisolid Metal Processing Techniques for Nondendritic Feedstock Production

Semisolid metal (SSM) processing or thixoforming is widely known as a technology that involves the formation of metal alloys between solidus and liquidus temperatures. For the procedure to operate successfully, the microstructure of the starting material must consist of solid near-globular grains surrounded by a liquid matrix and a wide solidus-to-liquidus transition area. Currently, this process is industrially successful, generating a variety of products with high quality parts in various industrial sectors. Throughout the years since its inception, a number of technologies to produce the appropriate globular microstructure have been developed and applied worldwide. The main aim of this paper is to classify the presently available SSM technologies and present a comprehensive review of the potential mechanisms that lead to microstructural alterations during the preparation of feedstock materials for SSM processing