The implementation of OFDM results in relatively high peak-to-average power ratio (PAPR) due to IFFT process to generate orthogonal subcarriers. A number of studies have attempted to apply various techniques to minimize PAPR by apllying the Wavelet transform as a substitution for Fourier transform. Another technique used to reduce the PAPR is clipping. In this thesis, the clipping technique was applied on the Wavelet based OFDM in mobile WiMAX standard to obtain better performance. The results indicate that Wavelet based OFDM has better immunity to noise and more resistant to Doppler shift than Fourier based OFDM. Sym 7 with Classical clipping and CR 1.2 can be selected and applied on wavelet-based OFDM in mobile WiMAX.
Keywords: Clipping; Fourier; Mobile Wimax; OFDM; PAPR; Wavelet
Analysis and Simulation of Wavelet Carrier Modulation with Clipping Techniques in Mobile WiMAX
LDPC is one of channel coding technique which can achieve the nearest to the shannon limit. The focus of this paper is to give improvement for LDPC error correcting process using message passing algorithm. This works used FPGA Cyclon II for implementing the process. This paper worked with two different LDPC matrix, matrix (8, 16) and matrix (24, 48). Matrix (24,48) had wc = 4 and wr = 8. Matrix (8, 16) had wc = 2 and wr = 4. The comparison of these two matrix would present the effects in the error correcting decision for message passing algorithm and the effect for implementing the algorithm on FPGA Cyclon II. This research purpose was to prove message passing algorithm can provide more than one bit error correction.
Several researches have been done to study the characteristics of the bonang barung, one of Javanese Gamelan music instrument. One of them is convertion of bonang barung single tone to numeric notation using Harmonic FFT as feature extraction and Backpropagation Artificial Neural Network (ANN) for classification. The tone detection accuracy result from previous research is 70,74%. In this research we try to improve the detection result by searching the dominant features using Wrapper Feature Subset Selection (WFSS). Sequential forward selection (SFS) and sequential backward selection (SBS) are used as searching algorithm. The input of the system is a song recorded from a bonang barung then the detected tone is converted into numeric notation. From the experiment, WFSS-SFS produced 6 features with 86,4% accuracy while WFSS-SBS give a better result, it produced 13 features with 92,9% accuracy of tone detection.
Audio Steganography using Modified Enhanced Least Significant Bit in 802.11n
H. Carolus Ferdy Setiaji, T. Suhartono, H.Bambang
Steganography is a technique to improve the security of data, which is by inserting messages or confidential information using a medium called the host or carrier or cover. A wide variety of digital media can be used as a host, among others audio, image, video, text, header, IP datagram, and so forth. For audio steganography, the embedded audio is called stego-audio. Steganography can be cracked by using steganalysis. By exploiting the weaknesses of each steganography method. Many steganography method has been developed to increase its performance. This work proposed audio steganography scheme called Modified Enhanced Least Significant Bit (MELSB) which is modified version of Enhanced Least Significant Bit (ELSB). This method using Modified Bit Selection Rule to increase SNR and robustness of stego-audio. SNR result after applying MELSB scheme is increased. MELSB scheme also increase robustness of stego-audio. MELSB still work fine until amplification level 1.07. MELSB also work fine against noise addition better than ELSB and LSB. It give BER and CER with value 0 at SNR 33 dB. MELSB work fine in real-time condition on 802.11n WLAN if there is no transcoding and noise addition between sender’s and recipient’s computer
Keywords: Audio; Steganography; Modified Enhanced Least Significant Bit
Simulation of Temperature Distribution in Horizontal Fin Heat Sink CPU Processor Using Comsol Multiphysics and Proportional Control
T.D. Sugiarto, R.F. Iskandar, I.P. Handayani
This research is aimed to analyze and simulate the temperature distribution in heat sink CPU processor. The study analyzes the heat absorption from the heat source to the bottom of the heat sink, the conduction process, and the forced convection process. All processes are simulated with software Comsol Multiphysics 4.4 to obtain the optimal heat sink design. The simulation is performed by varying the number of fins, the fin thickness, the air gap between two fins, the fin surface area, and the convection coefficient. The optimal design is found for heat sink with 40 pieces fins, fin thickness of 0.4 mm, air gap of 2.4 mm, fin surface area of 9425 mm2, and the convection coefficient of 5.26 W/m2.K. Further simulation shows that PID control improved the forced convection process. A proportional control (P) is reasonable enough to achieve a settled convection process. A settling temperature occurs at 241 s after heat is applied to the system. This is faster than non-controlled convection process which requires 1600 s instead. Additional integration and derivative controls will increase stability at later time.
Design and Implementation System Automatic Guided Vehicle (AGV) Using RFID for Position Information
Ibnu Waldy, Angga Rusdinar, Estananto
Manufactured goods distribution system is a very important part in the production chain. Delivery of goods from one point to another point affects the effectiveness of the production process. At the moment, most companies whose business are in manufacturing require automation, including distribution of goods. One application of automation in the distribution of goods is AGV (Automated Guided Vehicle). Companies need AGV that can move in complex pathways. The movement includes a selection of AGV path traversed and AGV terminal position. This research discusses the design and implementation of an AGV navigation and position information settings. AGV navigation uses fuzzy logic in its algorithm, while position setting of the AGV uses Radio Frequency Identification (RFID) to recognize the position of the robot at each terminal. From the testing result, the system obtained a success rate of 96% in movement of the robot from one terminal to another terminal using the RFID. RFID can be read at both speed of the robot i.e. 6,9 and 7,13 m/min.