Chittagong University of Engineering & Technology

About: Chittagong University of Engineering & Technology is a education organization based out in Chittagong, Bangladesh. It is known for research contribution in the topics: Renewable energy & Dielectric. The organization has 1200 authors who have published 1444 publications receiving 10418 citations. The organization is also known as: Engineering College, Chittagong & Bangladesh Institute of Technology, Chittagong.

Performance of multi-stage threshold decoding in MC-CDMA

Abstract: A decoding method, multi-stage threshold decoding for multicarrier code division multiple access (MTD/MC-CDMA) is proposed. Under two different channels, AWGN and Rayleigh fading (multipath), the comparative studies of BER performance between MTD/MC-CDMA and uncoded MC-CDMA is presented. Results show that MTD/MC-CDMA saves 5dB power under AWGN channel and 12dB power under Rayleigh fading channel (18-paths) for same process gain. MTD/MC-CDMA reduces BER to 10−6 at 20dB Eb/No (fading channel) and 8dB Eb/No (AWGN channel).

Audio Watermarking Based on FWHT and LUD

Abstract: This chapter introduces an audio watermarking algorithm based on FWHT and LU decomposition (LUD). To the best of our knowledge, this is the first audio watermarking method based on FWHT, LUD, and quantization jointly. Initially, we preprocess the watermark data to enhance the security of the proposed algorithm. Then, the original audio is segmented into nonoverlapping frames and FWHT is applied to each frame. LUD is applied to the FWHT coefficients represented in a matrix form. Watermark data are embedded into the largest element of the upper triangular matrix obtained from the FWHT coefficients of each frame. Experimental results indicate that proposed algorithm is considerably robust and reliable against various attacks without degrading the quality of the watermarked audio. Moreover, it shows more excellent results than the state-of-the-art methods in terms of imperceptibility, robustness, and data payload. The main limitation of the existing audio watermarking techniques is the difficulty to obtain a favorable trade-off among imperceptibility, robustness, and data payload. To overcome this limitation, in this chapter, we propose a blind audio watermarking algorithm based on fast Walsh-Hadamard transform (FWHT) and LU decomposition (LUD). The main features of the proposed scheme are: (i) it utilizes the FWHT, LUD, and quantization jointly; (ii) it uses a tent map that contains the chaotic characteristic to enhance the confidentiality of the proposed algorithm; (iii) watermark is embedded into the largest element of the upper triangular matrix obtained from the FWHT coefficients of each frame by quantization; (iv) watermark extraction process is blind; and (v) it achieves a good trade-off among imperceptibility, robustness, and data payload. Experimental results indicate that the proposed watermarking algorithm shows high robustness against various attacks such as noise addition, cropping, re-sampling, re-quantization, and MP3 compression. Moreover, it outperforms state-of-the-art methods [9–10, 15–16, 20, 22–23, 26, 28] in terms of imperceptibility, robustness, and data payload.

Comparative Study of Object Shape Recognition using Ultrasonic Sensor Arrays with Artificial Neural Network

Abstract: In this paper, attempts are made to detect some basic shape of objects using ultrasonic sensor arrays with Artificial Neural Network (ANN). For this purpose two types of ultrasonic sensor array are designed on prototype basis using HCSR04 ultrasonic sensors. The time of flight (TOF) variations of the sensors are considered as the features for the recognition unit. The objects are kept at a fixed distance from the sensor array to measure the TOF. The TOF of different sensors varies with the different object's shape. The two tools of ANN named ‘Function Fitting' and ‘Pattern Recognition' are used as shape recognition unit. These tools are trained with particular objects data. During the testing phase, the previously trained neural networks are recalled to detect the desired shape of the objects. Based on the detection results of two ANN tools a comparative study is redacted between the hexagonal sensor array and 3x3 sensor array. The study observed that, the 3x3 sensor array under ‘Function Fitting' tool gives the better result of shape detection. Moreover, this system avoids the complexity of signal conditioning algorithm and circuitry. It can be incorporated within a smart device to aid the blind people if this system is fine-tuned properly.

Perception of thermal comfort and prediction of heat stress (PHS) due to heat gain in tropical university classrooms

Abstract: Comfortable indoor climate is anticipated in hot-humid tropical condition. University classrooms are such kind of space which quality can improve the occupant's performance directly. Due to lack of their adaptation ability, like the fixed schedule of activities and clothing causes extra heat gain from the environment and make hazardous situation. In this research, we focused to find out the comfortable condition of university classrooms in Bangladesh. The field monitoring was conducted at Chittagong University of Engineering and Technology (CUET) during the hottest months in the country (April-July). The measurements included the basic thermal environmental parameters like air temperature (AT), relative humidity (RH), indoor air velocity (V), and indoor Light (L) during regular class time 9:00 to 17:00. Predicted Heat Strain (PHS) has been calculated using obtained data with a known metabolic rate and clothing. It is found that the skin temperature crosses 34°C frequently in PHS scale and creates health risk.

Effective Front Contact Layer for Physical and Optical Performance of Perovskite Solar Cell

Abstract: Modified simple design structure with efficient front contact layer as well as high efficiency of Perovskite solar cell is presented in this paper. Effect of cathode with different metal like Silver, Aluminum and Gold with nano-composite based cathode buffer layer is focused on designing the Efficient Perovskite solar cell. On this basis, an alternative structure is designed by using ZnO as Electron transport layer instead of TiO 2 for better performance. Moreover, SpiroOMeTAD is introduced in addition to high efficiency. 3-D analysis of Perovskite structure, overall performance analysis of Open Circuit Voltage (Voc), Short Circuit Current Density (Jsc), Maximum Power (Pmax), Fill Factor (FF) and Efficiency is calculated. 12.42% efficiency is found with the value 0.47volts, −365.24 Am−2 and 74.86 of Voc, Jsc and FF respectively. Furthermore, different physical analysis like graphical comparison among current, applied Voltage, charge density and current density as well as optical simulation of photon absorption, distribution, generation rate, and photon density are performed. This work is ultimately based on the analytical discussion over the designed cell for obtaining high efficiency and cost effective cell by solving the problem of complex structure.