You Kok Yeow

Quantifying system performance improvements in a high-density spectrum-sliced channel running at 10 Gb∕s using semiconductor optical amplifier gain compression nonlinearities

Abstract. We report on the use of semiconductor optical amplifier (SOA) gain compression for achieving intensity noise reduction in light from an incoherent broadband source, running at high data rate of 10  Gb/s in a narrow spectrum-sliced high-intensity channel of 20 GHz (∼0.16  nm) bandwidth, in order to improve quality of performance in future spectrum-sliced systems. Data have been collected on the performance of a single SOA as noise reducer at various input powers and biases. Improvements of ∼20  dB in the relative intensity noise, together with commensurate improvements in both signal-to-noise ratio and quality factor, have been achieved at a nominal 0 dBm of power inserted into the SOA at 0.15 A bias. The overall results obtained herein give designers a knowledge of the best SOA operating conditions required, particularly in terms of bias and input power, in order to achieve a desired intensity noise reduction, and thus an overall system performance improvement, while still obtaining some signal gain from the SOA as well.

Application of in-situ method for measuring sound absorption coefficient of direct piercing carved wood panel with daun sireh motif

An application of In-Situ method of measuring sound absorption coefficient on the surface of direct piercing carved wood panel using the concept of ensemble averaged is discussed. The method offer an easier way to measure the absorption performance for each individual aperture of carved wood panel with floral pattern which was replicated from one of the oldest mosque, namely Masjid Abidin located in Terengganu, Malaysia. Two pieces of 20 mm thick of cengal wood (Neobalanocarpus heimii) with 30% and 40% perforation ratio were respectively measured in a reverberation room in order to determine the value of . At lower frequencies (0.1 kHz-1.5 kHz), the measured values of for both direct piercing carved wood panel with floral pattern (Daun Sireh motif) are shown that the sound absoption for both direct piercing carved wood panel are in perform level. From the measurements, clearly, the installation of the direct piercing carved wood panel with floral pattern (Daun Sireh motif) in the Masjid Abidin can provide better air circulation and additional natural sunlight, as well as better sound intelligibility inside the building.

Application of bandpass filter as a sensor for rice characterization

This paper introduces the potential of the bandpass filter to implement as a microwave sensor for rice characterization. Three different filter sensors are design in order to operate at frequency range between 1.5 GHz to 3 GHz. The reflection coefficient, Γ and transmission coefficient, T performances for the sensors have been analyzed. Three types of rice samples, ‘Sakura Super Thai Brown Rice (SSTBR)’, ‘Sakura Basmati Pakistan Rice (SBPR)’ and ‘Giant Super Special Rice (GSSR)’ were used in this study. Results obtained showed 4th order filter gave the most sensitive for the reflection measurements, but more loss in transmission measurements. The results are served as the preliminary data for further investigation.

Correlation between Reflection Coefficient, Dielectric Properties and Brix Level of Malaysian Oranges at Microwave Frequencies

With the rapid growth of communications via the Internet, the need for an effective firewall system which has not badly affect the overall network performances has been increased. In this paper, a Field Programmable Gate Array (FPGA) -based firewall system with high performance has been implemented using Network FPGA (NetFPGA) with Xilinx Kintex-7 XC7K325T FPGA. Based on NetFPGA reference router project, a NetFPGA-based firewall system was implemented. The hardware module performs rule matching operation using content addressable memory (CAM) for higher speed data processing. To evaluate system performance, throughput, latency, and memory utilization were measured for different cases using different tools, also the number of rules that an incoming packet is subjected to was varied to get more readings using both software and hardware features. The results showed that the designed firewall system provides better performance than traditional firewalls. System throughput was doubled times of the one with Linux-Iptables firewalls.

CST Simulation on Monopole Sensor for Determination of Malaysian Local Oranges Sweetness Quality Non-destructively

This paper presents the application of monopole sensor for determination of sweetness level of local oranges in Malaysia which can be investigated non-destructively. Simulation using Computer Simulation Technology (CST) version 2012 was carried out to observe the effect on reflection coefficient (S11) when the monopole sensors grounding dimension is varied. The unique design of a holder for local oranges that is made of nylon is enclosed in this project contributed to its invention. The experiment test bed was set up based on standard dimension of small monopole sensor available in the market. Actual measurement on Malaysian local oranges was measured and its dielectric permittivity is predicted using CST software.

Portable Microwave Instrumentation System for Determination of Moisture Content in Oil Palm Fruits

In this paper, we present an improved instrumentation system for moisture content determination in oil palm fruit. The results obtained using the developed system are compared with the data obtained using the vector network analyzer, values calculated from finite element method (FEM) simulation and capacitance model at 2 GHz. This system is found to be more practical, cost effective, and accurate for in situ measurements than existing techniques.