Advanced LSTM: A Study about Better Time Dependency Modeling in Emotion Recognition

Long short-term memory (LSTM) is normally used in recurrent neural network (RNN) as basic recurrent unit. However,conventional LSTM assumes that the state at current time step depends on previous time step. This assumption constraints the time dependency modeling capability. In this study, we propose a new variation of LSTM, advanced LSTM (A-LSTM), for better temporal context modeling. We employ A-LSTM in weighted pooling RNN for emotion recognition. The A-LSTM outperforms the conventional LSTM by 5.5% relatively. The A-LSTM based weighted pooling RNN can also complement the state-of-the-art emotion classification framework. This shows the advantage of A-LSTM

End-to-end Audiovisual Speech Activity Detection with Bimodal Recurrent Neural Models

Speech activity detection (SAD) plays an important role in current speech processing systems, including automatic speech recognition (ASR). SAD is particularly difficult in environments with acoustic noise. A practical solution is to incorporate visual information, increasing the robustness of the SAD approach. An audiovisual system has the advantage of being robust to different speech modes (e.g., whisper speech) or background noise. Recent advances in audiovisual speech processing using deep learning have opened opportunities to capture in a principled way the temporal relationships between acoustic and visual features. This study explores this idea proposing a \emph{bimodal recurrent neural network} (BRNN) framework for SAD. The approach models the temporal dynamic of the sequential audiovisual data, improving the accuracy and robustness of the proposed SAD system. Instead of estimating hand-crafted features, the study investigates an end-to-end training approach, where acoustic and visual features are directly learned from the raw data during training. The experimental evaluation considers a large audiovisual corpus with over 60.8 hours of recordings, collected from 105 speakers. The results demonstrate that the proposed framework leads to absolute improvements up to 1.2% under practical scenarios over a VAD baseline using only audio implemented with deep neural network (DNN). The proposed approach achieves 92.7% F1-score when it is evaluated using the sensors from a portable tablet under noisy acoustic environment, which is only 1.0% lower than the performance obtained under ideal conditions (e.g., clean speech obtained with a high definition camera and a close-talking microphone).Comment: Submitted to Speech Communicatio

Impact of additional carbon on poly-hydroxybutyrates (PHB) accumulation and nutrient removal in a sustainable anaerobic/anoxic/oxic (A2O) membrane bioreactor

Recovering nutrient, energy, useful byproducts and reusing the treated wastewater may make a municipal wastewater treatment more sustainable. The approach employed in this study to increase the sustainability of wastewater treatment was to accumulate and harvest poly-hydroxybutyrates (PHB) in wastewater treatment plants. Additional carbon (acetate, supernatant of fermented sludge or thin corn stillage) was continuously fed along with synthetic municipal wastewater to a bench-scale anaerobic/anoxic/oxic (A2O) membrane bioreactor to promote PHB accumulation in the biomass. The impact of addition of carbon to the anaerobic tank or anoxic tank was also studied. PHB content in the range of 10% of dry biomass weight was achieved by adding 1000 mg-C/L acetate to either the anaerobic tank or anoxic tank. In addition, removal of total nitrogen and total phosphorus by the A2O MBR increased when acetate was added. Percent of nitrogen removal increased from 82.4% to 98%, and total phosphorus in effluent was reduced to as low as 0.4 mg/L. When supernatant of fermented sludge was added as additional carbon source, the PHB accumulation was about 4.2% of dry biomass weight. Adding supernatant of fermented sludge did not affect the effluent quality, and the total nitrogen and total phosphorus in the effluent were still within typical discharge limits. With thin corn stillage as an additional carbon source, a PHB content of 7.2% of dry biomass weight was obtained. However, use of corn stillage resulted in high TN, TP and COD in the effluent of the A2O MBR

Developing soybean oil-based coating and binding materials and environmental friendly solvent system for recovery of poly-β-hydroxybutyrate (PHB)

Driven by the industrial application needs and the desire to improve sustainability, my studies have focused on developing vegetable oil-based wax and binder alternatives to replace petroleum-based wax and animal product-based bird seed binder, and to improve the availability of natural waxes having desired properties but limited availability. A variety of soybean oil-based wax ester and amide derivatives were synthesized as potential paraffin and carnauba wax replacers, and a vegetable oil-based adhesive material was developed as an alternative to the gelatin-based bird seed binder. Some of the compounds showed physical properties such as hardness, cohesiveness and melting point, very comparable to paraffin and carnauba wax. The soybean oil-based binder was promising in providing seed cakes with good strength under different environmental conditions. The structure-function relationships of vegetable oil-based waxes were investigated and established. A work focusing on developing an environmental friendly solvent extraction system for the recovery of poly-β- hydroxybutyrate (PHB), a high-value biopolymer, was also included. The novel and solvent system was proven to be effective for extracting PHB from bacterial cells

Effect of temperature on deep lined circular tunnels in isotropic and transversely anisotropic elastic ground

A tunnel is a passageway constructed through soil or rock. It is one of the most important underground structures and has been widely used in transportation. Much research has been done on tunnel performance and on the interaction between ground, excavation, liner installation and support. The work has provided a better understanding of the interplay that exists between deformations and stresses transferred from the ground to the support. Significant insight into the problem has been provided by closed-form analytical solutions. A number of analytical formulations have been obtained for underground openings and lined tunnels under different scenarios, namely shallow or deep tunnels in the dry ground under geostatic loading, for static and seismic loading, plastic, poro-elastic, and poro-plastic conditions. However, considerably less attention has been given to thermal stresses in a tunnel. Temperature changes due to e.g. fire can cause cracking and damage to the liner and surrounding ground. In fact, a number of tunnels have suffered serious damage due to thermal loading. The French Channel Tunnel fire in 1996 and the Italian Mont Blanc tunnel fire in 1999 are well-known examples. The goals of this study are: (1) develop a general formulation for a deep circular lined tunnel in isotropic ground for thermal loading; (2) derive analytical solutions for stresses and displacements caused by thermal load for a lined circular tunnel under a transversely anisotropic ground where the ground anisotropy axis coincides with the stacking direction; (3) evaluate stresses and displacements for a lined deep tunnel in a transversely anisotropic medium also under thermal loading, with the ground anisotropy axis perpendicular to the stacking direction. Comparisons between the analytical solution obtained and the results obtained from ABAQUS for a number of select cases provide confidence in the formulations obtained. A parametric study has been performed to investigate the effects of Young’s modulus, Poisson’s ratio, thermal conductivity and the coefficient of thermal expansion on the behavior of the liner and ground, for a tunnel in a transversely anisotropic ground with the axis of the tunnel along one of the axis of elastic symmetry. The results of the study show that the Young’s modulus and the coefficient of thermal expansion are the most important parameters that determine the stresses and displacements of the liner and ground. The analysis also shows that the thermal conductivity has a significant effect on the temperature distribution in the ground