Square-rich fixed point polynomial evaluation on FPGAs

Polynomial evaluation is important across a wide range of application domains, so significant work has been done on accelerating its computation. The conventional algorithm, referred to as Horner's rule, involves the least number of steps but can lead to increased latency due to serial computation. Parallel evaluation algorithms such as Estrin's method have shorter latency than Horner's rule, but achieve this at the expense of large hardware overhead. This paper presents an efficient polynomial evaluation algorithm, which reforms the evaluation process to include an increased number of squaring steps. By using a squarer design that is more efficient than general multiplication, this can result in polynomial evaluation with a 57.9% latency reduction over Horner's rule and 14.6% over Estrin's method, while consuming less area than Horner's rule, when implemented on a Xilinx Virtex 6 FPGA. When applied in fixed point function evaluation, where precision requirements limit the rounding of operands, it still achieves a 52.4% performance gain compared to Horner's rule with only a 4% area overhead in evaluating 5th degree polynomials

Reconstruction of Phonated Speech from Whispers Using Formant-Derived Plausible Pitch Modulation

Whispering is a natural, unphonated, secondary aspect of speech communications for most people. However, it is the primary mechanism of communications for some speakers who have impaired voice production mechanisms, such as partial laryngectomees, as well as for those prescribed voice rest, which often follows surgery or damage to the larynx. Unlike most people, who choose when to whisper and when not to, these speakers may have little choice but to rely on whispers for much of their daily vocal interaction. Even though most speakers will whisper at times, and some speakers can only whisper, the majority of today’s computational speech technology systems assume or require phonated speech. This article considers conversion of whispers into natural-sounding phonated speech as a noninvasive prosthetic aid for people with voice impairments who can only whisper. As a by-product, the technique is also useful for unimpaired speakers who choose to whisper. Speech reconstruction systems can be classified into those requiring training and those that do not. Among the latter, a recent parametric reconstruction framework is explored and then enhanced through a refined estimation of plausible pitch from weighted formant differences. The improved reconstruction framework, with proposed formant-derived artificial pitch modulation, is validated through subjective and objective comparison tests alongside state-of-the-art alternatives

Whisper-to-speech conversion using restricted Boltzmann machine arrays

Whispers are a natural vocal communication mechanism, in which vocal cords do not vibrate normally. Lack of glottal-induced pitch leads to low energy, and an inherent noise-like spectral distribution reduces intelligibility. Much research has been devoted to processing of whispers, including conversion of whispers to speech. Unfortunately, among several approaches, the best reconstructed speech to date still contains obviously artificial muffles and suffers from an unnatural prosody. To address these issues, the novel use of multiple restricted Boltzmann machines (RBMs) is reported as a statistical conversion model between whisper and speech spectral envelopes. Moreover, the accuracy of estimated pitch is improved using machine learning techniques for pitch estimation within only voiced (V) regions. Both objective and subjective evaluations show that this new method improves the quality of whisper-reconstructed speech compared with the state-of-the-art approaches

Basic science232. Certolizumab pegol prevents pro-inflammatory alterations in endothelial cell function

Background: Cardiovascular disease is a major comorbidity of rheumatoid arthritis (RA) and a leading cause of death. Chronic systemic inflammation involving tumour necrosis factor alpha (TNF) could contribute to endothelial activation and atherogenesis. A number of anti-TNF therapies are in current use for the treatment of RA, including certolizumab pegol (CZP), (Cimzia ®; UCB, Belgium). Anti-TNF therapy has been associated with reduced clinical cardiovascular disease risk and ameliorated vascular function in RA patients. However, the specific effects of TNF inhibitors on endothelial cell function are largely unknown. Our aim was to investigate the mechanisms underpinning CZP effects on TNF-activated human endothelial cells. Methods: Human aortic endothelial cells (HAoECs) were cultured in vitro and exposed to a) TNF alone, b) TNF plus CZP, or c) neither agent. Microarray analysis was used to examine the transcriptional profile of cells treated for 6 hrs and quantitative polymerase chain reaction (qPCR) analysed gene expression at 1, 3, 6 and 24 hrs. NF-κB localization and IκB degradation were investigated using immunocytochemistry, high content analysis and western blotting. Flow cytometry was conducted to detect microparticle release from HAoECs. Results: Transcriptional profiling revealed that while TNF alone had strong effects on endothelial gene expression, TNF and CZP in combination produced a global gene expression pattern similar to untreated control. The two most highly up-regulated genes in response to TNF treatment were adhesion molecules E-selectin and VCAM-1 (q 0.2 compared to control; p > 0.05 compared to TNF alone). The NF-κB pathway was confirmed as a downstream target of TNF-induced HAoEC activation, via nuclear translocation of NF-κB and degradation of IκB, effects which were abolished by treatment with CZP. In addition, flow cytometry detected an increased production of endothelial microparticles in TNF-activated HAoECs, which was prevented by treatment with CZP. Conclusions: We have found at a cellular level that a clinically available TNF inhibitor, CZP reduces the expression of adhesion molecule expression, and prevents TNF-induced activation of the NF-κB pathway. Furthermore, CZP prevents the production of microparticles by activated endothelial cells. This could be central to the prevention of inflammatory environments underlying these conditions and measurement of microparticles has potential as a novel prognostic marker for future cardiovascular events in this patient group. Disclosure statement: Y.A. received a research grant from UCB. I.B. received a research grant from UCB. S.H. received a research grant from UCB. All other authors have declared no conflicts of interes

BHPR research: qualitative1. Complex reasoning determines patients' perception of outcome following foot surgery in rheumatoid arhtritis

Background: Foot surgery is common in patients with RA but research into surgical outcomes is limited and conceptually flawed as current outcome measures lack face validity: to date no one has asked patients what is important to them. This study aimed to determine which factors are important to patients when evaluating the success of foot surgery in RA Methods: Semi structured interviews of RA patients who had undergone foot surgery were conducted and transcribed verbatim. Thematic analysis of interviews was conducted to explore issues that were important to patients. Results: 11 RA patients (9 ♂, mean age 59, dis dur = 22yrs, mean of 3 yrs post op) with mixed experiences of foot surgery were interviewed. Patients interpreted outcome in respect to a multitude of factors, frequently positive change in one aspect contrasted with negative opinions about another. Overall, four major themes emerged. Function: Functional ability & participation in valued activities were very important to patients. Walking ability was a key concern but patients interpreted levels of activity in light of other aspects of their disease, reflecting on change in functional ability more than overall level. Positive feelings of improved mobility were often moderated by negative self perception ("I mean, I still walk like a waddling duck”). Appearance: Appearance was important to almost all patients but perhaps the most complex theme of all. Physical appearance, foot shape, and footwear were closely interlinked, yet patients saw these as distinct separate concepts. Patients need to legitimize these feelings was clear and they frequently entered into a defensive repertoire ("it's not cosmetic surgery; it's something that's more important than that, you know?”). Clinician opinion: Surgeons' post operative evaluation of the procedure was very influential. The impact of this appraisal continued to affect patients' lasting impression irrespective of how the outcome compared to their initial goals ("when he'd done it ... he said that hasn't worked as good as he'd wanted to ... but the pain has gone”). Pain: Whilst pain was important to almost all patients, it appeared to be less important than the other themes. Pain was predominately raised when it influenced other themes, such as function; many still felt the need to legitimize their foot pain in order for health professionals to take it seriously ("in the end I went to my GP because it had happened a few times and I went to an orthopaedic surgeon who was quite dismissive of it, it was like what are you complaining about”). Conclusions: Patients interpret the outcome of foot surgery using a multitude of interrelated factors, particularly functional ability, appearance and surgeons' appraisal of the procedure. While pain was often noted, this appeared less important than other factors in the overall outcome of the surgery. Future research into foot surgery should incorporate the complexity of how patients determine their outcome Disclosure statement: All authors have declared no conflicts of interes

Speech playback geometry for smart homes

Smart homes are environments that intelligently communicate with users, primarily through speech, to control various devices and activities relating to daily living. Both automatic speech recognition and text-to-speech are enabling technologies, however the basic home environment is often acoustically noisy and unconstrained in usage, leading to significant practical difficulties with both key technologies. In addition to interfering noise problems, a home occupant may not always be located physically close to either a microphone or loudspeaker. Speech intelligibility in a smart home depends on many factors including background noise, speech power and content. It is also affected by the orientation of the listeners' ears with respect to the speech source. This paper describes a simple technique to adjust perceived phase angle, and reports results from experiments to assess how the intelligibility of speech heard in such an environment will vary with respect to head position

Whisper vowel diagrams for Singapore English

Whispered speech, as a relatively common form of communications, has received little research effort in spite of its usefulness in everyday vocal communications. Apart from a few notable studies analysing the main whispered vowels and some quite general estimations of whispered speech characteristics, a classic vowel space determination has been lacking for whispers. Aligning with our previous published work which aimed to redress this shortfall by presenting a vowel formant space for whispered speech, this paper studies Singapore English (SgE) from this respect. Furthermore, by comparing the shift amounts between normal and whispered vowel formants in two different English accents (British West Midlands and SgE), the study also considers the question of generalisation of shift amount and direction for two dissimilar accent groupings. It is further suggested that the shift amounts for each vowel are almost consistent for F2 while these vary for F1, making it difficult to propose a general correlation between normal and whispered vowels. This paper presents the results of the formant analysis, in terms of acoustic vowel space mappings, showing differences between normal and whispered speech for SgE, and compares this to results obtained from the analysis of more standard English

The use of low-frequency ultrasonics in speech processing

One phonetically significant and growing application of ultrasound is ultrasonic speech, as a contribution of ultrasound to speech analysis and processing. The technology acts to augment the human natural speech production system, using data extracted from ultrasonic analysis to synthesize elements of audible speech. In this application, an ultrasonic signal in the kHz range is injected into the vocal tract (VT), which propagates and resonates through the vocal cavities and is emitted from the mouth as ultrasonic speech. This signal could potentially be converted to audible speech by appropriate down-conversion. This chapter introduces ultrasonics, particularly low frequency (LF) ultrasonic waves, and analyses their interaction with the human vocal tract. Ultrasonic frequencies used in this application are relatively low (near-audible), extending upwards from the upper threshold of human hearing to around 100 kHz in frequency. These frequencies are easily generated, captured and recorded by much existing audio equipment – and can be readily processed in real-time with available hardware. In this chapter, the basic principles of ultrasonic speech technology and the most important issues concerning its implementation and signal processing are addressed. Most importantly, a modelling scheme describing ultrasonic behaviour within the VT is proposed and proven as the theoretical basis and the main framework of implementation of ultrasonic speech. This chapter concludes with open areas of research concerning the technology

Inter-hemispheric and spectral power analyses of binaural beat effects on the brain

Binaural beats are said to occur when two tones of different frequencies are presented to each ear, with the resulting perception being that of a single tone and a frequency midway between the two stimuli. It has found use in applications that purport to have the ability to relax the brain and other positive medical outcomes. This research considers the effects of binaural beats on the brain, following the assumption that the human brain has the tendency to change its dominant electroencephalography (EEG) frequency towards the frequency of the external stimulus. First, we considered the difference in spectral power of EEG frequencies for a group of individuals when in an entrained state (exposed to binaural beats) and a relaxed state (not exposed to binaural beats). Secondly, we assessed whether the effects of binaural beats affect the right and left hemisphere of the brain uniformly, and if so, to what extent this interhemispheric relationship can be seen. The results of this research show that hemispheric synchronisation affects all 5 subjects. Spectral power analysis revealed that 3 of the 5 subjects exhibited a difference in spectral power in the entrained state versus the relaxed state, especially in the frontal cortex but rather, in contradiction to the reports by others, as the effect was opposite, that is, entrainment reduces the spectral power, instead of causing an increase. The conclusion (based on the limited pool of subjects) is that there is some evidence to support that binaural beats do affect the brain but, in certain cases, negatively, and therefore, its usage should be weighed carefully