Abstract

This paper presents a trim-free, low-power, and high-precision voltage/current reference for IoT and biomedical applications. The voltage reference is generated by the proper addition of CTAT and PTAT voltages, whereas, the current reference is generated using a MOSFET in the active region, which acts like a resistor and helps in lowering power consumption without increasing the form factor. Implemented in the 90nm CMOS process, the proposed voltage/current reference outputs a voltage and current of 820mV and 3.23nA, respectively. Without trimming, the process variation of the proposed voltage/current reference is 1.34%(σ/μ) / 1.75%(σ/μ) and the temperature coefficient of the voltage/current reference is 62ppm/oC / 332ppm/oC over the temperature range of -40oC to 100oC. The line sensitivity of the voltage/current reference is 0.296%/V / 0.414%/V for a wide supply range of 1V - 3.5V. The area occupied by the total circuit is 0.0112mm2, while the total power consumption of the design is 37nW at the typical corner of 27oC and 1V supply.

Abstract

The pronunciation quality of second language (L2) learners can be affected by different factors including the fol- lowing seven factors: Intelligibility, Intonation, Phoneme quality, mispronunciation, Mother tongue influence, Correct placement of pause and Correct stress placement. An automatic assessment of these seven factors could be helpful for developing computer- assisted language learning systems. In this work, we assess the quality of all seven factors considering an unsupervised approach using DTW based utterance level alignment distance between expert’s and learner’s speech. Unlike the existing works that consider factor specific heuristic based features, we explore Wav2Vec-2.0 based self-supervised representations as a feature for assessing all the seven factors. The distance is computed using the following three distance metrics: Mean absolute error (MAE), Mean squared error (MSE) and Cosine distance (CD). Experiments are conducted on voisTUTOR corpus containing spoken English speech samples from 16 Indian L2 learners annotated with binary ratings (1 and 0) for all the factors. Using each distance metric, for each learner’s speech, four distance values are computed with a set of four expert samples. In the assessment, to circumvent the need for parallel expert data, we consider two (out of four) expert samples synthesized from the state-of-the-art text-to-speech (TTS) systems. We observe that the performance with the considered distance metric based unsupervised assessment approach is significantly more than that with the baseline for six out of seven factors under all three distance metrics and all four experts samples.

Abstract

The demand for high-quality speech data has been increasing as deep-learning approaches gain popularity in speech applications. Among these, automatic speech recognition (ASR) and text-to-speech (TTS) require large amount of data contain- ing speech and the corresponding text. For these applications, high-quality data is often obtained through manual validation, which ensures matching between speech and text. The manual validation is not scalable as per the demand due to the cost and time involved. In order to cater to the high-quality data demand, validating the data automatically could be useful. In this work, for automatic data validation, a spoken English corpus named IIITH MM2 Speech-Text is created, containing matched and mismatched speech-text pairs under read speech conditions from Indian speakers with different nativities. For the creation, we consider 100 unique stimuli selected from the TIMIT corpus, ensuring phonetic richness, for which a joint entropy maximization is proposed. These stimuli are recorded from 50 speakers, resulting in matched and mismatched sets containing 5000 and 764 utterances with a total duration of 6 hours and 1 hour, respectively. The mismatched set contains speech from the instances where the speakers naturally made spoken errors while reading the reference text. It also contains two stimuli per utterance, one stimulus is the reference text, and the other is manually annotated text that reflects the erroneous speech. Thus, the reference and the annotated text are used for building the models of speech-text mismatch detection and correction, respectively. To the best of our knowledge, no such corpora exist containing both matched and mismatched speech-text. As a preliminary analysis for speech-text mismatch detection, a baseline considering Wav2Vec-2.0 representations and DTW results in the detection F1-score of 0.87

Abstract

—This paper presents a sub-1V, 593 pA current reference without using resistors and amplifiers. Temperature compensation is achieved by incorporating a CTAT gate to source voltage and a PTAT drain to source voltage in an NMOSbased sub-threshold biased circuit. The proposed architecture achieves ± 3σ/µ process variation of ± 0.75%, which enables seamless trim-free operation. Implemented in the 90nm CMOS process, the temperature-compensated current reference achieves a temperature coefficient of 378 ppm/oC over a high-temperature range of -40 to 100 oC and a line sensitivity of 0.198%/V in a supply voltage range from 0.8 to 2.5 V. Duty cycling technique is adopted in the CTAT generator to reduce the total average power consumption. The proposed circuit occupies an area of 0.074 mm2 while consuming only 3.3 nW at a typical corner of 27 oC and 0.8 V supply.

Abstract

The Industrial Internet of Things (IIoT) is able to connect machines, analytics and people with IoT smart devices, gateway nodes and edge devices to create powerful intuitivenesses to drive smarter, faster and effective business agreements. IIoT having interconnected machines along with devices can monitor, gather, exchange, and analyze information. Since the communication among the entities in IIoT environment takes place insecurely (for instance, wireless communications and Internet), an intruder can easily tamper with the data. Moreover, physical theft of IoT smart devices provides an intruder to mount impersonation and other attacks. To handle such critical issues, in this work, we design a new private blockchain-envisioned access control scheme for Pervasive Edge Computing (PEC) in IIoT environment, called PBACS-PECIIoT. We consider the private blockchain consisting of the transactions and registration credentials of the entities related to IIoT, because the information is strictly confidential and private. The security of PBACS-PECIIoT is significantly improved due to usage of blockchain as immutability, transparency and decentralization along with protection of various potential attacks. A meticulous comparative analysis exhibits that PBACS-PECIIoT achieves greater security and more functionality features, and requires low costs for communication and computational as compared to other pertinent schemes.

Abstract

This study analysed temperature data in the contiguous Peninsular India from 1991-2020 using the PMiSTIC method, aiming to identify zones with consistent seasonal temperature patterns. Four seasons were considered: DJF, MAM, JJA, and SON, each revealing distinct temperature zones, especially in the high-elevation Himalayan region, with the Western Himalayan and Karakoram zones consistently identified. These regions exhibit Elevation Dependent Warming (EDW) phenomenon, with diurnal temperature range (DTR) being lowest in JJA and highest in MAM. Over the study period, both regions experienced rising temperatures, particularly in DJF and MAM, with the Western Himalayan region showing a slightly higher increase. JJA and SON also displayed increasing trends. Conversely, DJF saw a decreasing temperature trend. DTR exhibited a seasonal cycle, with lowest values in JJA and a gradual increase in SON. Notably, DTR increased during JJA but decreased in DJF. This analysis sheds light on the spatio-temporal variability of temperature patterns in the region, highlighting the influence of elevation on temperature trends throughout the year and the need to incorporate it in climate models for temperature projections

Abstract

Convolutional neural networks (CNN) applied to Mel spectrograms now have a dominant presence in the landscape of speaker recognition systems. Correspondingly, it is also important to evaluate their robustness to adversarial attacks that remains not thoroughly explored for end-to-end trained CNNs for speaker recognition. Our work addresses this gap and investigates variations of the iterative Fast Gradient Sign Method (FGSM) to perform adversarial attacks. We observe that a vanilla iterative FGSM can flip the identity of each speaker sample to that of every other speaker in the LibriSpeech dataset. Furthermore, we propose adversarial attacks specific to Mel spectrogram features by (a) limiting the number of pixels attacked, (b) restricting changes to specific frequency bands, (c) restricting changes to particular time duration, and (d) using a substitute model to craft the adversarial sample. Using thorough qualitative and quantitative results, we demonstrate the fragility and non-intuitive nature of the current CNN-based speaker recognition systems, where the predicted speaker identities can be flipped without any perceptible changes in the audio. The samples are available at "https://advdemo.github.io/speech/"

Abstract

Second language learners often make grammatical mistakes, which can impact the performance of Spoken Language Understanding (SLU) systems. SLU systems consist of two key components: Automatic Speech Recognition (ASR) and Natural Language Understanding (NLU). This work focuses on the effects of grammatical errors which were synthetically generated by manipulating Parts of Speech (POS) tokens on the NLU module. Our analysis comprises three main aspects. Firstly, we assess the impact of grammatical errors on the overall performance of NLU systems, specifically in the domains of Intent Detection and Slot Filling. Secondly, we investigate NLU performance concerning POS tags. Lastly, we utilize an Attention-based NLU model to evaluate the significance of different POS. This study evaluates NLU models on ATIS and SNIPS datasets for Intent Detection and Slot Filling tasks with introduced grammatical errors, leading to a significant performance drop as large as 4.7% for Intent Detection and 5.1% for Slot Filling. However, training on datasets with synthetic errors helps mitigate this drop, and the models are shown to be sensitive to increasing levels of corrupted tokens. Additionally, attention analysis reveals Proper Nouns’ higher weights in determining intent, while specific POS corruption, particularly Auxiliary Verbs and Nouns, is more likely to cause intent misclassification.

Abstract

No Results Found

Abstract

Prior work has shown that pretrained language models often make incorrect predictions for negated inputs. The reason for this behaviour has remained unclear. It has been argued that since language models (LMs) don’t change their predictions about factual propositions under negation, they might not detect negation. We show encoder LMs do detect negation as their representations across layers reliably distinguish negated inputs from non-negated inputs, and when negation leads to contradictions. However, probing experiments show that these LMs indeed don’t use negation when evaluating whether a factual statement is true, even when fine-tuned with the objective of changing outputs on negated sentences (Hosseini et al., 2021). We hypothesize about why pretrained LMs are inconsistent under negation: when the statement could refer to multiple ground entities with conflicting properties, negation may not entail a change in output. This means negation minimal pairs in different training samples can have the same completion in pretraining corpora. We argue pretraining may not provide enough signal to learn the distribution of ground referents a token could have, confusing the LM on how to handle negation.