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: Computer science & Renewable energy. 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.

Prediction of Trihalomethanes in water supply of Chattogram city by empirical models and cancer risk through multi-pathway exposure

Abstract: This study predicts the possible occurrence of trihalomethanes (THMs) in water supply of Chattrogram city in Bangladesh, and life time cancer risk from multi-pathway intakes of the trihalomethanes (THMs) to the city dwellers. A total of 11 water samples were collected from the distribution network of the city, and few water quality parameters were analyzed in the study. Three empirical models developed by Amy et al. (1998), Rathbun (1996), and Malcolm Pirnie (1993) were used to estimate the level of THMs from measured water quality data, and were denoted as MODEL1, MODEL2 and MODEL3, respectively in the study. Lifetime cancer risk was estimated using predicted chronic daily intakes (CDI) of THMs' species for different exposure routes (ingestion, inhalation and dermal). The total concentrations of THMs ranged between 20 and 440 μg/L, 95–215 μg/L and 162–249 μg/L were predicted by MODEL1, MODEL2 and MODEL3, respectively. An average lifetime cancer risk was predicted as 1.4 × 10−4, 1.1 × 10−4 and 2.9 × 10−4 for oral, inhalation and dermal exposure, respectively from the water supply of the city. Percent contribution to total lifetime cancer risk were predicted as 50, 40 and10 for oral ingestion, inhalation and dermal absorption, respectively. The study revealed that lifetime cancer risk values were higher than minimum risk level set by United States Environmental Protection Agency. The findings of possible occurrence of THMs in the water supply and associated cancer risk might be beneficial as baseline data for further investigation, and help the decision makers regarding the formulation of standards and legislations of THMs.

The challenges and alternatives of water supply and sanitation in flood prone area: A case study for Bhuapur in Bangladesh

Abstract: Bangladesh is a riverine country and frequently affected by floods. Depending on location and sanitation conditions, drinking water sources are often contaminated during flood and many waterborne diseases like dysentery, diarrhea, typhoid etc. spread out. This research investigates potable water and sanitation condition in a flood affected area at Bhuapur in Tangail, Bangladesh. The various parameters such as colour (25 TCU), turbidity (128 NTU), total coliform (1800/100 ml) and faecal coliform (80/100 ml) for raw water collected from Halda river and during flood is much higher as compared to the Bangladesh standard limit. It is recommended that fabricated biosand filter should be used at flood prone area because it can significantly remove impurities such as turbidity over 95.28% and 87.82% for Halda river and flooded tubewell water respectively. The test results for other parameters like colour, total and faecal coliform have been compared with WHO guide lines and Bangladesh standards and found within the acceptable limits. Besides, alternative sanitary latrines have also been suggested to protect sanitation during flood.

An Efficient Image Watermarking System Based on Error Correcting Codes in DCT Domain

Abstract: Digital watermarking has drawn extensive attention for copyright protection of multimedia data. This paper proposes a new watermarking system for digital images using efficient systematic linear block codes (SLBC) in discrete cosine transform (DCT) domain. The proposed watermarking system using SLBC generates a code sequence of {0, 1} that provides error correction capabilities and then replaces it with a binary watermark sequence of {-1, 1}. This achieves more robust invisible image watermarks and requires a small storage unit for binary sequence numbers. The generated watermark sequence is then used as an input for our proposed watermarking system which consists of watermark embedding process and watermark detection process. Experimental results indicate that the invisible watermark embedded with the proposed system are very robust against various kinds of attacks such as white Gaussian noise, JPEG compression, median, and mean filtering, by showing similarity values ranging from 0.7 to 0.8. K EY W ORDS : Digital Watermarking; Linear Block Code; Copyright Protection. DOI: http://dx.doi.org/10.3329/mist.v3i0.8056

Measuring speech perception with recovered envelope cues using the peripheral auditory model

Abstract: Speech perception refers to how understandable speech produced by a speaker would be by a listener. The human auditory system usually interprets this information using both envelope (ENV) and temporal fine structure (TFS) cues. While ENV is sufficient for understanding speech in quiet, TFS cues are necessary for speech segregation in noisy conditions. In general, ENV can be recovered from the TFS (known as recovered ENV); however, the degree of ENV recovery and its significance on speech perception are not clearly known/understood. In order to systematically assess the relative contribution of the recovered ENV for speech perception, this study proposes a new speech perception metric. The proposed metric employs a phenomenological model of the auditory periphery developed by Zilany and colleagues (J. Acoust. Soc. Am. 126, 283–286, 2014) to simulate the responses of the auditory nerve fibers to both original and recovered ENV cues. The performance of the proposed metric was evaluated under different types of noise (both steady-state and fluctuating noise), as well as several classes of distortion (e.g., peak-clipping, center-clipping, and phase jitter). Finally, to validate the proposed metric, the predicted scores were compared with subjective evaluation scores from behavioral studies. The proposed metric indicates a statistically significant correlation for all cases and accounts for a wider dynamic range compared to the existing metrics.

A microstrip antenna with circular polarization switching capability for X-band applications

Abstract: This paper describes a novel microstrip patch antenna with switchable circular polarization. A square patch whose two top corners are truncated by a square portion is used to realize the proposed antenna. Two Schottky diodes connected in the opposite direction are used to correlate the separated corner segments with the patch by their switching operation. As a result, RHCP and LHCP can be alternated by controlling the state of the two diodes. High impedance networks grounded through a via-hole are employed to isolate the DC bias networks from the RF signal. The measured 3-dB axial ratio bandwidth for both RHCP and LHCP is around 1%.