Papers by NANDINI CHANDRA NAG
Review: Design Aspects of Reconfigurable Antenna
The study of reconfigurable antennas has made great progress in recent research. Compared with co... more The study of reconfigurable antennas has made great progress in recent research. Compared with conventional antennas, reconfigurable antennas have more advantages and better prospects. They are lighter in weight, smaller in dimension and lower in price. Moreover, the reconfigurable antennas can provide diversity feature of operating resonant frequency, polarization, and radiation pattern. Reconfigurable antenna are analyzed and summarized in this paper to present the characteristics, classifications and reconfigurable techniques. Reconfigurable antenna implementation can be differentiated into three main processes: Antenna design, simulation, and optimization. The aim of this paper is to present approach into the antenna designing that must be made to employ a reconfigurable antenna, serving as information for future reconfigurable antenna designers as to what requirements to be done before a model is constructed, such as choosing a suitable antenna structure and reconfiguration tec...
Mobile and wireless technology is growing at a rapid rate. These advances have resulted in breakt... more Mobile and wireless technology is growing at a rapid rate. These advances have resulted in breakthroughs that have made feasible several prospects that were thought as impossible. Ad hoc networks are a consequence of the ceaseless research efforts in Mobile and Wireless networks. Ad hoc network is a class of wireless networks where there is no fixed infrastructure. Unlike traditional networks they do not have base stations to coordinate the activities of mobile hosts. In this paper we proposed the authentication scheme using CBRP in MANETS. Here we have explored the concept of MANETS in location database management with proper authentication. For this purpose we have presented a distributed network consisting of two clusters along with their cluster heads. KeywordsAuthentication, CBRP, Cluster,
International Journal of Computing and Digital Systems, 2022
A complex acoustic scenario comprising overlapping speeches from multiple speakers in the presenc... more A complex acoustic scenario comprising overlapping speeches from multiple speakers in the presence of noise renders speech recognition perform poorly in hands-free devices. This scenario turns out to be more complex in India, a country where 96.71% of the population speaks one of the 22 scheduled languages. Therefore, an audio source separation algorithm that mitigates the interference from other speakers and effectively enhances the articulacy and quality of source speech may be added as a pre-processor in speech recognition systems. This research, therefore, investigates the non-negative matrix factorization (NMF) algorithm's effectiveness for the separation of source in an overlapping multilingual multi-dialect single-channel speech mixture scenario, an inherent characteristic of a cocktail party problem in India. The objective is to analyze the signal level metrics and perception level metrics of a speech source-separated from a multilingual overlapped speech signal. The languages used for the same are English and two Indo-Aryan languages, Marathi and Bengali. One of the experimental results demonstrated that the source to distortion ratio (SDR) of separated target source from English-Bengali and English-Marathi speech mixture is 0.4 and 1.3 dB higher than English-English speech mixed signals, respectively. Therefore, the experiments highlight an improvement in separating sources from mixed speech signals with different language combinations than the same language.
Understanding basis functions for vowels based on non-negative matrix factorization
2017 International Conference on Nascent Technologies in Engineering (ICNTE), 2017
With the advent of hands free devices, speech recognition is of utmost importance but miserably f... more With the advent of hands free devices, speech recognition is of utmost importance but miserably fails to be perfect in a cock-tail party environment without speech separation or speech denoising. There are various techniques available for speech separation but the one technique used nowadays is non-negative matrix factorization (NMF). Non-negative matrix factorization decomposes the mixed signal into components namely the basis functions matrix and activation or weight matrix. Speech separation using NMF is successful, if the mixed signal consists of uncorrelated sources. In this paper we revisit the concept of decomposition using NMF for vowel utterances by various speakers and analyse them to identify correlation which may exist among the basis functions. This may be useful for formulating better training bases which eventually will lead to successful speech separation.
International Journal of Advanced Computer Science and Applications, 2021
Non-negative matrix factorization-based audio source separation separating a target source has sh... more Non-negative matrix factorization-based audio source separation separating a target source has shown significant performance improvement when the spectral bases attained after factorization exhibits latent structures in the mixed audio signal comprising multiple speaker sources. If all the sources are known, the spectral bases may be inferred on priority by using a training process on the database of isolated sources. The number of bases inferred for a source should not include bases matching spectral patterns of the interfering sources in the audio mixture; otherwise, the estimated target source after separation will be incorporated with undesirable spectral patterns. It is difficult to distinguish and separate similar audio sources in an overlapped speech, leading to a complex speech processing task. Therefore, this research attempts to learn an optimum number of bases for Indian languages leading to successful separation of target source in multilingual multiple speaker speech mixtures using non-negative matrix factorization. The languages used for utterances are Hindi, Marathi, Gujarati, and Bengali. The speaker combinations used are female-female, male-male, and female-male. The optimum number of bases which was determined by evaluating improvement in the separation performance was found to be 40 for all the languages considered.
Investigating Single Channel Source Separation Using Non-Negative Matrix Factorization and Its Variants for Overlapping Speech Signal
2019 International Conference on Nascent Technologies in Engineering (ICNTE)
A pre-processor to speech recognition, audio source separation may mitigate the problem of qualit... more A pre-processor to speech recognition, audio source separation may mitigate the problem of quality degradation of individual signal recognition in scenarios like cock-tail party environment. The same may be used for various other applications like audio forensics, speaker verification, instrument identification, hearing aids, etc. There are various techniques available for single channel audio source separation, but the technique based on Non-negative Matrix Factorization (NMF) is widely used. Several research studies have shown considerable performance improvement of signal separation using NMF on different mixture of audio signals like speech with noise, speech with music, speech with speech taken from different audio databases. In this paper, single channel source separation using Non-Negative Matrix Factorization and its variants for two-speaker mixed signal is investigated using same speech database, the GRID speech corpus. The separation performances of phase-aware algorithms are compared with phase-unaware approaches based on NMF and its variants. The quality of separated speech was judged by varying parameters such as number of bases and analysis window size.
Uploads
Papers by NANDINI CHANDRA NAG