Weighted-Sampling Audio Adversarial Example Attack

Recent studies have highlighted audio adversarial examples as a ubiquitous threat to state-of-the-art automatic speech recognition systems. Thorough studies on how to effectively generate adversarial examples are essential to prevent potential attacks. Despite many research on this, the efficiency and the robustness of existing works are not yet satisfactory. In this paper, we propose~\textit{weighted-sampling audio adversarial examples}, focusing on the numbers and the weights of distortion to reinforce the attack. Further, we apply a denoising method in the loss function to make the adversarial attack more imperceptible. Experiments show that our method is the first in the field to generate audio adversarial examples with low noise and high audio robustness at the minute time-consuming level.Comment: https://aaai.org/Papers/AAAI/2020GB/AAAI-LiuXL.9260.pd

Design and manufacturing of high precision roll-to-roll multilayer printing machine -- machine upgrade

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 79-80).In 2008, a group of MIT Master of Engineering students built a roll to roll machine for printing thiol onto a flexible gold substrate by self-assembly. The machine demonstrated good performance in high speed printing (400 ft/min). Since single layer printing is limited in industrial application, we reconfigured this machine for multi-layer printing . Our project includes developing a device that can fabricate high quality stamps, which is vital in print quality; increasing the roll to roll machine accuracy in critical components, which helps increases the machine's repeatability. In addition, we have designed a multilayer printing system using the same technology and demonstrated it with the upgraded machine. The flat stamp cast by the new machine can achieve the flatness of ±16 [micro]m with thickness of 1194 [micro]m, compared to ±32 [micro]m of stamp made with other machine. An initial experiment with multi-layer printing using the upgraded machine has shown that better control of the roll drive system and better registration measurement will be required to meet the necessary specification. However, the first experiment did can achieve alignment errors of 1017 [micro]m along the printing direction and 113 [micro]m across the printing directionby Yufei Zhu.M.Eng

Bound states around impurities in a superconducting bilayer

We theoretically study the appearance of bound states around impurities in a superconducting bilayer. We focus our attention on $s$-wave pairing, which includes unconventional odd-parity states permitted by the layer degree of freedom. Utilizing numerical mean-field and analytical $T$-matrix methods, we survey the bound state spectrum produced by momentum-independent impurity potentials in this model. For even-parity $s$-wave pairing bound states are only found for impurities which break time-reversal symmetry. For odd-parity $s$-wave states, in contrast, bound states are generically found for all impurity potentials, and fall into six distinct categories. This categorization remains valid for nodal gaps. Our results are conveniently understood in terms of the ``superconducting fitness'' concept, and show an interplay between the pair-breaking effects of the impurity and the normal-state band structure

Process optimization and insecticidal activity of alkaloids from the root bark of Catalpa ovata G. Don by response surface methodology

Purpose: To optimize the extraction of total alkaloids from the root bark of Catalpa ovata using response surface methodology, and to determine the insecticidal activity of the total alkaloids extracted. Methods: A combination of Box-Behnken design and response surface methodology  (RSM) was used to optimize the acid water extraction of total alkaloids from the root bark of Catalpa ovata, with extraction rate of total alkaloids as index and the single factor experiment as basis, and the extraction time, material: liquid ratio and pH as 3 factors. The insecticidal activity of total alkaloids was determined against the three instar armyworm Mythimna separata (Lepidoptera: Noctuidae) and  diamondback moth Plutella xylostella (Lepidoptera: Plutellidae).Results: The optimum extraction conditions for total alkaloids were: material: liquid ratio of 1:10; extraction time of 3 h, pH of 1.0, and simmering. Under these  conditions, total alkaloid extraction was 8.62 %, which was very close to the experimental value. The results were accurate and reliable, with reference value. The insecticidal activity of the total alkaloids indicate that when the concentration of the total alkaloids was 10 mg/L, the fatality rate of Plutella xyllostella and oriental armyworm was over 89 %, but the insecticidal activity of the total alkaloids was lower than that of avermectin which was employed as a reference.Conclusion: The alkaloids from the root bark of Catalpa ovata are potential botanical insecticides.Keywords: Catalpa ovata, Root bark, Total alkaloids, Response surface  methodology, Insecticidal activit

Does My Dog ''Speak'' Like Me? The Acoustic Correlation between Pet Dogs and Their Human Owners

How hosts language influence their pets' vocalization is an interesting yet underexplored problem. This paper presents a preliminary investigation into the possible correlation between domestic dog vocal expressions and their human host's language environment. We first present a new dataset of Shiba Inu dog vocals from YouTube, which provides 7500 clean sound clips, including their contextual information of these vocals and their owner's speech clips with a carefully-designed data processing pipeline. The contextual information includes the scene category in which the vocal was recorded, the dog's location and activity. With a classification task and prominent factor analysis, we discover significant acoustic differences in the dog vocals from the two language environments. We further identify some acoustic features from dog vocalizations that are potentially correlated to their host language patterns

Chemical components of volatile oil from Cinnamomum jensenianum Hand Mazz leaf in Yongzhou, and its antibacterial and antioxidant properties

Purpose: To study the chemical components, and in vitro antibacterial and antioxidant properties of volatile oil extracted from Yongzhou Cinnamomum jensenianum Hand. Mazz leaves.Methods: The extraction process of volatile oil in the leaves of Yongzhou Cinnamomum jensenianum Hand. Mazz was optimized with respect to volatile oil yield, and the oil was subjected to gas chromatography-mass spectrometry (GC-MS) analysis. In vitro antimicrobial activities against bacteria and fungi were evaluated by the filter paper method, while in vitro antioxidant potential was determined by assaying its ability to scavenge DPPH radicals.Results: The optimized extraction conditions for volatile oil from the leaves of Yongzhou Cinnamomum jensenianum Hand. Mazz were 3.5 h extraction time, solid-liquid ratio of 1:10, and soaking time of 4 h, which resulted in volatile oil yield of 2.4 ± 0.19 %. A total of 37 components were isolated and identified, accounting for 99.19 % of the volatile oil. The in vitro antimicrobial activities against bacteria and fungi were significant, with minimum inhibitory concentration (MIC) between 10 and 20 uL. At a volatile oil concentration of 0.09 mg/mL, the DPPH scavenging ability of the oil was stronger than that of BHT.Conclusion: There is a high level of extractability of volatile oil from the leaves of Yongzhou Cinnamomum jensenianum Hand. Mazz. The main component is linalool (94.45 %), and it has good antibacterial and antioxidant properties.Keywords: Yongzhou Cinnamomum jensenianum Hand. Mazz, Volatile oil, Antibacterial, Antioxidan