Unsupervised Speech Representation Pooling Using Vector Quantization

With the advent of general-purpose speech representations from large-scale self-supervised models, applying a single model to multiple downstream tasks is becoming a de-facto approach. However, the pooling problem remains; the length of speech representations is inherently variable. The naive average pooling is often used, even though it ignores the characteristics of speech, such as differently lengthed phonemes. Hence, we design a novel pooling method to squash acoustically similar representations via vector quantization, which does not require additional training, unlike attention-based pooling. Further, we evaluate various unsupervised pooling methods on various self-supervised models. We gather diverse methods scattered around speech and text to evaluate on various tasks: keyword spotting, speaker identification, intent classification, and emotion recognition. Finally, we quantitatively and qualitatively analyze our method, comparing it with supervised pooling methods

Electroluminescence in polymer-fullerene photovoltaic cells

We report electroluminescence (EL) in photovoltaic (PV) cells based on semiconducting polymer-fullerene composites. By applying a forward bias to the PV cells, the devices exhibited a clear EL action with a peak around 1.5 eV. We ascribe this peak to an "electric field-assisted exciplex" formed between the electrons in the fullerenes and the holes in the polymers, thereby resulting in radiative recombination in the composites. This finding is totally unexpected because of a strong photoluminescence quenching in the same materials. Since the same devices also showed typical photovoltaic effects under illumination, our results demonstrate a dual functionality in one device; polymer photovoltaic cells and polymer light-emitting diodes.open464

Improved performance of polymer light-emitting diodes with nanocomposites

The characteristics of a hybrid polymer light-emitting diode (HPLED) with an active layer of poly [2-methoxy,5-(2-ethylhexoxy)-1,4-phenylenevinylene] blended with Au-capped TiO(2) nanocomposites are reported. Both the increased current in the active layer and low turn-on voltage were attributed to incorporation of Au-capped TiO(2) in the electroluminescent polymer. The maximal brightness of 11 630 cd/m(2) was observed in HPLED with a 1:1 ratio of Au-capped TiO(2). The enhanced performance was attributed to the roughness assisted charge transport induced by the Au-capped TiO(2) nanocomposites in the active polymer.open111

Isomeric iminofullerenes as acceptors in bulk heterojunction organic solar cells

Two stable iminofullerene isomers, [5,6]-open azafulleroid (open APCBM) and [6,6]-closed aziridinofullerene (closed APCBM) enable us to scrutinize the use of these new acceptors in polymer bulk heterojunction (BHJ) solar cells and compare the effects of open trans- and closed trans-annlar subunits. When we compared the performance of both isomer devices, the poly(3-hexylthiophene)(P3HT):open APCBM device demonstrates an enhancement in photocurrent in comparison with the P3HT: closed APCBM device. From the comparative study, we attribute the enhanced current to the lower degree of symmetry of open APCBM. The alteration of fullerene structure from closed to open breaks its high degree of symmetry and consequently leads to an improved bulk heterojunction with the electron donating conjugated polymer.close242

Some determinants of addictive buying behavior

This study examined which factors influenced addictive buying and proposed a model of determinants of addictive buying. The assumption was that a childhood experience of parental loss influenced depression which, in turn, increased addictive buying behavior in adulthood. Also, low self-esteem was assumed to influence the development of addictive buying. The data were obtained from questionnaires completed by 149 subjects (college students, Chicago residents, or members of Debtors Anonymous). There were no differences in depression and addictive buying between people with and without the experience of parental loss. The results of LISREL analysis indicated that parental loss was not significantly related to depression and addictive buying. Depression was negatively related to self-esteem and positively related to addictive buying. Women were found to have greater tendencies toward addictive buying than men. Two sets of analyses explored assumptions behind this study. First, the role of shopping as a mood elevator was examined and found to not only not function in this manner but to actually lower mood. It is noteworthy, however, that this drop in mood was not present for addicts. Second, respondents felt that overbuying is more likely to cause a feeling of depression or low self-esteem than depression or low self-esteem is to cause a need to buy a lot

Dual-channel charge transfer doping of graphene by sulfuric acid

© 2021 Korean Chemical Society, Seoul & Wiley-VCH GmbHTwo-dimensional materials represented by graphene and transition metal dichalcogenides undergo charge transfer (CT) processes and become hole-doped in strong mineral acids. Nonetheless, their mechanisms remain unclear or controversial. This work proposes and verifies two distinctive CT channels in sulfuric acids, respectively, driven by oxygen reduction reaction involving O2/H2O redox couples and reduction of bisulfate or related species. Acid-induced changes in the charge density of graphene were in situ quantified as a function of oxygen content using Raman spectroscopy. At acid concentrations lower than 6 M, the former channel is operative, requiring dissolved O2. Above 6 M, the degree of CT was even higher because the former is cooperated with by the latter channel, which does not need dissolved oxygen. The mechanism revealed in this study will advance our fundamental understanding of how low-dimensional materials interact with chemical environments.11Nsciescopuskc

Charge Transfer at Graphene-Environment Interface Driven by O2/H2O Redox Reactions

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Mechanism of Spontaneous and Thermally Activated Hole Doping in Graphene on Silica Substrate

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Dynamic correction of image distortions for a kinect-projector system

This paper addresses the problem of correcting distortion in an image projected onto a target screen without using a camera. Unlike a camera-projector system that projects a special pattern on the screen and acquires it using a camera for distortion correction, the proposed system computes the amount of correction directly from the geometric shape of the screen, which is captured by a Kinect device, a scanner that produces 3D points of the screen shape. We modified the two-pass rendering method that has been used for the projector-camera system. An image is created on the Kinect plane. Next, the image is mapped to the 3D points of the screen shape obtained by the Kinect device using the ray-surface intersection method. Finally, a corrected image is obtained by transforming the image on the 3D point set to the projector plane. The proposed method does not require a marker or a pattern and can be used in a dynamic environment where the shape of the screen changes, or either the viewer’s position and direction change. Various tests demonstrate the performance of the proposed method