Designing and development of voice to machine interfacing technique

In this paper, microcontroller based automatic door open system has been developed. The system is developed as speech recognition circuit where programmable voice is used as reference. Programmable means trained voice has been used for identification of authorized and unauthorized person. As software part, MATLAB GUI interface has been used to record authorized voice, and to synthesize the recorded voice with feature extraction such as power spectral density of peak frequency by FFT (Fast Fourier Transform). Then these features will be verified with every incoming voice. This voice activity detection (VAD) is designed and developed to divide the speech signal into speech segment and non-speech segments. As hardware part, ARDUINO microcontroller has been used to implement the circuitry for this well trained automatic security system. This system is with low cost and well-performed in less noisy environment. Accuracy has been obtained around 99%. This system can also be applicable for other controlled access services like voice based biometrics, database access services, voice based dialing, voice mail and remote access to the computers.</p

Phytochemical Screening and Evaluation of Antioxidant, Antibacterial and Cytotoxicity Activities of Methanolic and Ethanolic Extracts of Enhydra fluctuans Lour (Helencha) (Family: Asteraceae) Stems and Leaves

Aims: To investigate the presence of various phytochemicals and to evaluate DPPH scavenging activity, total flavonoid content, antimicrobial and cytotoxic activities of the different extracts of Enhydra fluctuans lour. Place and Duration of Study: The study was carried out between June 2017 to November 2017 in the Department of Pharmacy, Daffodil International University, Dhaka, Bangladesh. Methodology: The leaves and stems of Enhydra fluctuans lour were extracted with ethanol and methanol. By qualitative analysis phytochemical evaluation was carried out using DPPH scavenging activity and total flavonoid content determined in vitro antioxidant activity of the crude extract. Cytotoxic activity was determined by using brine shrimp lethality bioassay and antimicrobial activity was determined by using disc diffusion method. Results: The presence of flavonoids, steroids, saponins, carbohydrates, vitamin C, alkaloids, diterpenthees, and amino acids are influence by phytochemical study. The DPPH radical scavenging activity of methanolic and ethanolic extract were mild to moderate than ascorbic acid (standard). The IC50 value of methanolic and ethanolic extract were respectively 619.55,115.67 µg/ml compared with the standard ascorbic acid with IC50 value of 17.81 µg/ml. The total flavonoid contents were 67 mg (QE/gm extract) and 21 mg (QE/gm extract) for 500 µg/ml concentration for two extract. The ethanolic extract of 400 µg/disc exhibited the highest zone of inhibition of 12 mm against Escherichia coli. The LC50 value of methanolic and ethanolic extract were 3.29, 27.446 µg/ml respectively compared with the standard vincristine sulphate with&nbsp; LC50 value of 0.632 mg/ml. Conclusion:&nbsp; All of those study of a methanolic and ethanolic extract of Enhydra fluctuans prove that it has an antioxidant, antimicrobial and cytotoxic activity