Kasumawati Lias

Performances analysis of VoIP over 802.11b and 802.11e using different CODECs

This project is to simulate the Voice over Internet Protocol (VoIP) over IEEE 802.11b and 802.11e WLANs (Wireless Local Area Network) with different Coder-Decoder (CODECs) by using Network Simulator-2 (NS-2). The main objectives of this project are to analyze the VoIP of Mean Opinion Score (MOS), throughput and packet drop rate. The simulation is conducted using different CODECs (G.711, G.729A and G.723.1) and simulated without background traffic (data). The simulation in this project is using 1 wired node and 1 access point connected with mobile nodes in hierarchy. The mobile nodes will send VoIP calls to wired node through access point simultaneously. From the project, it is found that the CODEC G.711 provides the best quality of VoIP calls. However, CODEC G.723.1 can support the most VoIP calls with acceptable quality. In addition, with the first priority given by 802.11e to the VoIP, it can provide a very good perceived audio quality.

Biological Effect of 900MHz and 1800MHz Mobile Phones in SAR Weight

In recent years, the public concern on human biological effect of mobile phone is increasing due to the widely used of mobile phones by public including the children. As a consequences, a safety guidelines have been established by the various public organization such as World Health Organization (WHO) and International Commission on Non-Ionization Radiation Protection (ICNIRP). The main objective of this paper is to investigate and study on the human biological effect that may cause by the used of 900MHz and 1800MHz mobile phones. For the purpose of the assessment, Finite-Difference Time Domain (FDTD) is used to simulate the modeling of mobile phone attached to human head in order to obtain the Specific Absorption Rate (SAR) value of mobile phones that absorbed into human head. The minimum SAR value stated by International Commission on Non-Ionization Radiation Protection (ICNIRP) is 2W/kg. When the limit is exceeds, it may produces adverse human health effects that contibute to reverse cell membrane polarity, alter brain waves and damage DNA. This leads to cancer and memory loss. However, mobile phones are designed with low power and operate at high frequency, resulted in lower SAR value comparing to 2W/kg that stated by ICNIRP. Other temporary biological or potential human health effects that may produce by mobile phones are heating, headache, fuzziness, fatigue and nausea. By the way, further studies or researches are needed in order to draw more complete picture of health risks that may cause by the used of mobile phones.

Human health implication of 900MHz and 1800MHz mobile phones

In recent years, there has been increasing public concern about the health implication of Electromagnetic (EM) wave exposures due to the mobile phone. For this reason, various public organizations in the world have been established safety guidelines. This paper focused on the investigation or study of human health effect that cause by the used of 900MHz and 1800MHz mobile phones. For the purpose of the assessment, Finite-Difference Time Domain (FDTD) is used to find the Specific Absorption Rate (SAR) value of mobile phones that absorbed into human head. The minimum SAR value stated by International Commission on Non-Ionization Radiation Protection (ICNIRP) is 4W/kg. When the limit is exceeds, it produces human health effects where it can caused reverse cell membrane polarity, alter brain waves and brain chemistry and damage DNA. This leads to cancer and memory loss. However, mobile phones are designed with low power and operate at high frequency where the value of SAR is lower than the limit that stated by ICNIRP. Other temporary biological or potential human health effects produce by mobile phones are heating, headache, fuzziness, fatigue and nausea. By the way, further studies or researches are needed in order to draw more complete picture of health risks that cause by the use of mobile phones.

Fault Detection using Dynamic Parity Space Approach

This paper review the effectiveness of the parity space approach to identify faults or disturbance in a system. The most commonly used is the observer based procedures, and redundancy relationship method. This involves analytical mathematical analysis of geometry and bilinear algebra. Then, technological advances which require complex computation such as artificial intelligence and genetic algorithm had made tremendous improvement to fault Detection and Isolation (FDI) analysis. Dynamic Parity Space Approach was studied for a discrete state-space model. Important data will be extracted using this approach especially for residual generation which is the backbones of FDI analysis. Subsequently, at each time instant k, the generated residuals will form a matrix that will define the fault signature. It is remarkable that this approach is proven in this study to be effective in diagnosis and faults isolation.

Electromagnetic radiation towards adult human head from 900MHz handheld mobile phone

Electromagnetic radiation produce by mobile phone and the relationship with the humans health is not a new issue nowadays. Since the used of mobile phone had increased rapidly over the past few years, people are becoming more concern with their health when dealing with the so-called electromagnetic radiation. This type of radiation would leads to heating of body tissue at specific rate called the thermal radiation. Thermal radiation depends on the frequency of the energy, the power density of the radio frequency field that strikes the body and the polarization of wave. This paper will discuss on the result collected from the thermal radiation generated by handheld mobile phone with frequency of 900 MHz towards adult human head. The analysis is conducted in a laboratory with average of 45 minutes talking hour with two different types of mobile phone, internal and external antenna. The results show an increased of heat especially at the place near the ear skull after 45 minutes of operation. When comparing both different types of mobile phone, mobile phone with external antenna produce more heat compared to mobile phone with internal antenna.

Visualization and Analytical Measurement of Electromagnetic Radiation from Handheld Mobile Phones

Mobile communication is where signal is transferred via electromagnetic wave through radio frequency and microwave signals. This signal produced electromagnetic radiation in the form of thermal radiation that consists of harmful ionizing radiation and harmless non-ionizing radiation. When using mobile phone, electromagnetic wave is transferred to the body in the form of thermal radiation that might cause health problems especially at the place near ear skull region for a certain period of time (talking time or operation time). In this analysis, the simulation and experimental analysis are carried out to examine the effect of electromagnetic radiation towards design phantom (dry phantom), water molecules and human volunteer when using the mobile phone for 45 minutes talking hour. This analysis is conducted in an anechoic chamber. Simulation is done using MATLAB’s software to show the radiation produced by the mobile phone. In the experimental analysis, thermal imaging technique is used to monitor and capture temperature distribution towards design phantom and human head. Two different design of mobile phone are used with internal (built-in) and external monopole antenna serving two different GSM frequencies GSM 900 and GSM 1800. The results show that mobile phones produced electromagnetic radiation (thermal) towards human head with high radiation produced by mobile phone with external antenna serving for GSM 900 MHz.

Full reference image quality metrics and their performance

This paper mainly aims to study the performance of objective assessment methods of image quality. It take into consideration the correlations between each objective assessment and the subjective assessment in order to determine objective test performance. Three objective assessment methods used in this study are the Structural Similarity (SSIM) index, the Peak Signal-to-Noise Ratio (PSNR) and the Mean Squared Error (MSE) calculating algorithm. The resulting data indicate what type of objective assessment was most suitable for which type of impairment imposed upon an image. This is clarified using the Pearson Correlation Coefficient as described in the paper. As an overall, SSIM index had the best correlation characteristics to the subjective assessment, followed by the MSE calculating algorithm. From this study, a better understanding of the requirements for developing an efficient image quality assessment method was gained.

900MHz and 1800MHz mobile phone effect towards adult head in SAR distribution and SAR in weight

The investigation on the effect of mobile phone towards adult head in Specific Absorption Rate (SAR) Distribution and SAR in Weight is presented in this paper. Finite Different Time-Domain (FDTD) was used to construct adult head modeling with the attachment of monopole antenna and also to do a simulation in obtaining the SAR Distribution and SAR in Weight either 1g or 10g weight value, respectively. From the simulation, the results show that the values of both SAR are small and do not exceed 4W/kg stated by International Commission on Non-Ionizing Radiation Protection (ICNIRP), National Council on Radiation Protection and Measurement (NCRP) and Institute of Electrical and Electronics Engineers (IEEE). The simulation covered 900MHz and 1800MHz frequency with 0.6W radiated power.

Pseudo random binary sequence on second order system

Pseudo random binary sequence (PRBS) signal was developed using MATLAB software and used as a forcing function in simulated second order system. The autocorrelation function (ACF) of the input signal and cross correlation function (CCF) between input and output signal were performed using MATLAB software and transfer function of the system was estimated from the correlograms. For verification of the simulation work, PRBS generator circuit was build using transistor-transistor logic and analyzed using Dynamic Signal Analyzer (DSA). PRBS is used as forcing function to an unknown system. The ACF of the input signal and CCF between input and output signal were performed using DSA and the transfer function model of the unknown system was estimated.