Knowledge Distilled Ensemble Model for sEMG-based Silent Speech Interface

Voice disorders affect millions of people worldwide. Surface electromyography-based Silent Speech Interfaces (sEMG-based SSIs) have been explored as a potential solution for decades. However, previous works were limited by small vocabularies and manually extracted features from raw data. To address these limitations, we propose a lightweight deep learning knowledge-distilled ensemble model for sEMG-based SSI (KDE-SSI). Our model can classify a 26 NATO phonetic alphabets dataset with 3900 data samples, enabling the unambiguous generation of any English word through spelling. Extensive experiments validate the effectiveness of KDE-SSI, achieving a test accuracy of 85.9\%. Our findings also shed light on an end-to-end system for portable, practical equipment.Comment: 6 pages, 5 figure

A study on the impact of double external shocks on Chinese wholesale pork prices

IntroductionFluctuation in pork prices has always been a focus of academic attention. This paper examines the impact of double external shocks on pork prices, to provide reference for the impact of future outbreaks on the pork market.MethodsThis paper constructs a natural experiment based on the time and regional differences in the occurrence of the epidemics. Double difference models and triple difference models are used to identify the impacts of African swine fever and COVID-19 on Chinese pork prices.ResultsThe results found that both African swine fever and COVID-19 positively affected pork prices, but African swine fever had a greater degree of impact; before the COVID-19 epidemic, African swine fever caused a more significant increase in pork prices; the impact of a single African swine fever shock was greater than the double shocks.DiscussionThe COVID-19 epidemic may have curbed the further increase in pork prices, due to the decreased market consumption demand caused by the epidemic

Probing NaCl hydrate formation from aqueous solutions by Terahertz Time-Domain Spectroscopy

The cooling-induced formation of hydrate in aqueous NaCl solutions was probed using terahertz time-domain spectroscopy (THz-TDS). It was found that the NaCl hydrate formation is accompanied with emergence of four new absorption peaks at 1.60, 2.43, 3.34 and 3.78 THz. Combining the X-ray diffraction measurement with the solid-state based density functional theory (DFT) calculations, we assign the observed terahertz absorption peaks to the vibrational modes of the formed NaCl⋅2H2O hydrate during cooling. This work dedicates THz-TDS based analysis great potential in studying ionic hydrate and the newly revealed collective vibrational modes could be the sensitive indicators to achieve quantitative analysis in phase transitions and lattice dynamics

Three essays on corporate finance

In the first chapter, we show that stock liquidity negatively affects firms’ corporate social responsibility (CSR) ratings. To identify the causal effect, we use the decimalization of stock trading as an exogenous shock to liquidity. The negative liquidity effect on CSR is more pronounced for firms with CEOs approaching the retirement age, firms with more analyst coverage, and firms with more short-term institutional ownership. These findings suggest that liquidity discourages firms’ investment in CSR activities through inducing managerial short-termism. Our findings reveal the real effect of stock liquidity as an important stock market characteristic on firms’ engagement in CSR activities and highlight a dark side of liquidity in exacerbating the conflict between shareholders and other stakeholders. In the second chapter, we examine how stock liquidity affects firms’ timeliness of loss recognition in financial reporting, namely, conditional accounting conservatism. Using both the 1997 liquidity shock and the 2001 decimalization as exogenous shocks to stock liquidity, we establish a negative causal effect of stock liquidity on accounting conservatism. Our results are robust to alternative measures of conservatism and various definitions of stock liquidity. The negative effect is more pronounced for firms with higher long-term institutional ownership, firms with stronger presence of blockholders and activists, firms with bank debt, and firms with higher CEO ownership. These findings suggest a substitution effect of stock liquidity on accounting conservatism. Namely, higher liquidity improves governance through facilitating threat of intervention and threat of exit for shareholders, and thus shareholders rely less on accounting conservatism as a governance mechanism. In the third chapter, we analyze the effects of government credit on export activities in China by merging the universal transaction-level data from China Customs and loan data from the China Development Banks (CDB). We find that CDB credit to SOEs leads to higher export amount of SOEs and lower export product varieties of private firms in the same industry. Moreover, CDB credit to upstream industries leads to higher export amount and more export destinations of private firms in downstream industries. This effect is not pronounced for SOEs in downstream industries. Infrastructure credit generally has positive effects on export activities for all types of firms. We use the pre-determined turnover timing of municipal politicians as an instrument for CDB loans. The results suggest government credit to upstream industries could have positive spillover effects on private firms in the downstream industries.Doctor of Philosophy (NBS

Combating the COVID-19 pandemic: the role of the SARS imprint

We provide evidence of delayed attention and inaction in response to COVID-19 in countries that did not experience SARS in 2003. Using cross-country data, we find that individuals in countries that had SARS infections in 2003 searched more intensively for COVID-19-related information on Google in late January 2020, the time of the first known outbreak in Wuhan, China. Early attention to the novel virus, as measured by Google searches, is associated with deeper stock market drops in countries with SARS experience. In contrast, people in countries without SARS experience started to pay more attention much later, in March. Moreover, governments in these countries responded significantly more slowly in implementing social distancing policies to combat domestic COVID-19 outbreaks than governments in countries with SARS experience. Moreover, such early responses of individuals and governments in countries with SARS experience are prevalent within continent, even in non-Asian countries. Furthermore, people in countries with SARS experience are more compliant with social distancing rules. These timely attention and proactive responses of individuals and governments are more pronounced in countries that reported deaths caused by SARS, which left deeper imprints. Our findings suggest that the imprint of similar viruses’ experience is a fundamental mechanism underlying timely responses to COVID-19.Ministry of Education (MOE)This work was supported by Ministry of Education, Singapore, under its Tier 1 RG60/17, University of Macau, Start-up Research Grant [SRG2019-00151-FBA]

Oxidation Resistance and Wetting Behavior of MgO-C Refractories: Effect of Carbon Content

Various carbon contents in the MgO-C refractory were studied with respect to the oxidation resistance and the wetting behavior with slag. The bulk density, apparent porosity, cold crushing strength, oxidation rate, and mass loss rate of the fired MgO-C refractories with various carbon contents were measured and compared. The wetting and penetration behavior of the cured MgO-C refractory with the molten slag were observed in-situ. The contact angle and the shape parameters of molten slag, including the apparent radius, height, and volume were compared. The results showed that the regenerated MgO effectively restrained the carbon oxidation in the MgO-C refractory, which was more evident at the low carbon content refractory. The contact angle between the MgO-C refractory and the molten slag increased as the carbon content increased. The increased contact angle decreased the penetration of the molten slag

interaction relationships of caches in agent-based hd video surveillance: discovery and utilization

In the research of networked HD video surveillance, various caches embedded in the IP camera, the data management server and the network proxy server are used for lossless video storage and complete playback. How to utilize agent technology to achieve effective and collaborative caching in the end-to-end process of video capture, network data transmission and video data management, has been considered as an emerging solution. However, on one hand, according to the cache's location in HD video surveillance implementation, all caches can form a top-down hierarchical structure in a vertical direction; while on the other hand, according to the cache's storage performance such as free storage space, "similar" caches at the same level can be grouped by clustering in a horizontal direction. Hence, how to discover the complex interaction relationships among caches by considering both vertical and horizontal directions and further effectively make optimized video stream transmission though collaborative caching is still an open and challenging problem. In this paper, we designed an agent-based collaborative caching model, in which three roles of agents: the Capturer Agent, the Transmitter Agent and the Manager Agent are developed for discovering the intrinsic interaction relationships of caches. By utilizing the relationship, approaches to controlling caching activities and planning video stream transmission are further proposed. The case study and experimental evaluations demonstrate the capability of the proposed approach for HD video surveillance. © 2013 Elsevier Ltd. All rights reserved.In the research of networked HD video surveillance, various caches embedded in the IP camera, the data management server and the network proxy server are used for lossless video storage and complete playback. How to utilize agent technology to achieve effective and collaborative caching in the end-to-end process of video capture, network data transmission and video data management, has been considered as an emerging solution. However, on one hand, according to the cache's location in HD video surveillance implementation, all caches can form a top-down hierarchical structure in a vertical direction; while on the other hand, according to the cache's storage performance such as free storage space, "similar" caches at the same level can be grouped by clustering in a horizontal direction. Hence, how to discover the complex interaction relationships among caches by considering both vertical and horizontal directions and further effectively make optimized video stream transmission though collaborative caching is still an open and challenging problem. In this paper, we designed an agent-based collaborative caching model, in which three roles of agents: the Capturer Agent, the Transmitter Agent and the Manager Agent are developed for discovering the intrinsic interaction relationships of caches. By utilizing the relationship, approaches to controlling caching activities and planning video stream transmission are further proposed. The case study and experimental evaluations demonstrate the capability of the proposed approach for HD video surveillance. © 2013 Elsevier Ltd. All rights reserved