1,729 research outputs found

    Electrical characteristics of novel heterojunction diodes of thin relaxation semiconductors/p-Si/

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    The relaxation semiconductor is defined as one in which the dielectric relaxation time (τd;resistivity times permittivity) is greater than lifetime (τo). Non-hydrogenated amorphous Silicon Carbide (SiC) and KrF excimer laser induced disordered Si were used for the relaxation semiconductors. Both semiconductors have high resistivity, wide energy gap, and numerous defects. A novel diode, consisting of those semiconductors on p-type crystalline Silicon (c-Si), was fabricated. In the diode structure, an injecting contact was made on the relaxation material and a Schottky barrier contact was made on the c-Si. Electrical characteristics of both diodes were found to have interesting effects: negative capacitance, negative resistance, space charge limited current, and bistable switching with long term memory. During the C-V measurement of a disordered Si/c-Si heterojunction diode, for the first time, a constant negative capacitance of 1520pF was observed from - 10v to 10v at 1MHz. This negative capacitance was considered as an inductive behavior. The measured inductance value was approximately 16.7 µH at 1MHz. The inductance was proportional to 1/ω2 in the variation of frequency and 14.74mH at 30KHz as measured by a LCR analyzer. In an a-SiC/c-Si heterojunction diode, a negative capacitance was also observed in both biases. The inductance value was 36µH above 3.5v and below 3.5v at 1MHz. The shape of negative capacitance between - 3.5v and 3.5v was parabolic and the inductance, near zero bias, was 30µH. The inductance was almost constant between 1MHz and 30KHz. An inductive part of the heterojunction diode was derived theoretically using the relaxation theory and Shockley theory. The inductance was either constant if ωτd \u3c 1, or proportional to 1/ω2 ωτd \u3e 1. Moreover, a circuit model of the heterojunction diode was also developed. The negative capacitance, Ctest showed |Ctest| = 1/ω2 Ltest at the circuit model. Computer simulation also showed negative capacitance similar to that of the experiment. It was proposed that conductivity modulation, by carrier injection in a thin relaxation semiconductor, causes an inductive behavior, and the relaxation would be more pronounced by the carrier screening of impurities. The novel heterojunction diode may replace a physical inductor in microelectronics

    Interactive animated storybook based on Korean folk tale

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    The intended purpose of my project was to develop an interactive animated storybook for children based on a Korean folk tale. Unlike a traditional storybook, I created an interactive computer program for children with diverse interactive animations. I wanted to explore how multimedia design can be entertaining and educational simultaneously

    Reinforcement Learning-based Virtual Fixtures for Teleoperation of Hydraulic Construction Machine

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    The utilization of teleoperation is a crucial aspect of the construction industry, as it enables operators to control machines safely from a distance. However, remote operation of these machines at a joint level using individual joysticks necessitates extensive training for operators to achieve proficiency due to their multiple degrees of freedom. Additionally, verifying the machine resulting motion is only possible after execution, making optimal control challenging. In addressing this issue, this study proposes a reinforcement learning-based approach to optimize task performance. The control policy acquired through learning is used to provide instructions on efficiently controlling and coordinating multiple joints. To evaluate the effectiveness of the proposed framework, a user study is conducted with a Brokk 170 construction machine by assessing its performance in a typical construction task involving inserting a chisel into a borehole. The effectiveness of the proposed framework is evaluated by comparing the performance of participants in the presence and absence of virtual fixtures. This study results demonstrate the proposed framework potential in enhancing the teleoperation process in the construction industry

    Single-cell transcriptional regulation and genetic evolution of neuroendocrine prostate cancer

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    Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer, with a 10% five-year survival rate. However, little is known about its origin and the mechanisms governing its emergence. Our study characterized ADPC and NEPC in prostate tumors from 7 patients using scRNA-seq. First, we identified two NEPC gene expression signatures representing different phases o

    Investigation of a Switchable Textile Communication System on the Human Body

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    In this paper, a switchable textile communication system working at 2.45 GHz ISM band is presented and studied for different locations within a realistic on-body environment. A 3D laser scanner is used to generate a numerical phantom of the measured subject to improve the accuracy of the simulations which are carried out for different body postures. For the off-body communications, the system is acting as an aperture coupled microstrip patch antenna with a boresight gain of 1.48 dBi. On-body communication is achieved by using a textile stripline, which gives approximately 5 dB transmission loss over 600 mm distance. The system is switched between on and off-body modes by PIN diodes. Common issues, such as shape distortion and body detuning effects which the textile antenna may experience in realistic use are fully discussed. Robust antenna performance is noted in the on-body tests, and an additional 3 dB transmission coefficient deduction was noticed in the most severe shape distortion case

    MetaMix: Meta-state Precision Searcher for Mixed-precision Activation Quantization

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    Mixed-precision quantization of efficient networks often suffer from activation instability encountered in the exploration of bit selections. To address this problem, we propose a novel method called MetaMix which consists of bit selection and weight training phases. The bit selection phase iterates two steps, (1) the mixed-precision-aware weight update, and (2) the bit-search training with the fixed mixed-precision-aware weights, both of which combined reduce activation instability in mixed-precision quantization and contribute to fast and high-quality bit selection. The weight training phase exploits the weights and step sizes trained in the bit selection phase and fine-tunes them thereby offering fast training. Our experiments with efficient and hard-to-quantize networks, i.e., MobileNet v2 and v3, and ResNet-18 on ImageNet show that our proposed method pushes the boundary of mixed-precision quantization, in terms of accuracy vs. operations, by outperforming both mixed- and single-precision SOTA methods

    CSGM Designer: a platform for designing cross-species intron-spanning genic markers linked with genome information of legumes.

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    BackgroundGenetic markers are tools that can facilitate molecular breeding, even in species lacking genomic resources. An important class of genetic markers is those based on orthologous genes, because they can guide hypotheses about conserved gene function, a situation that is well documented for a number of agronomic traits. For under-studied species a key bottleneck in gene-based marker development is the need to develop molecular tools (e.g., oligonucleotide primers) that reliably access genes with orthology to the genomes of well-characterized reference species.ResultsHere we report an efficient platform for the design of cross-species gene-derived markers in legumes. The automated platform, named CSGM Designer (URL: http://tgil.donga.ac.kr/CSGMdesigner), facilitates rapid and systematic design of cross-species genic markers. The underlying database is composed of genome data from five legume species whose genomes are substantially characterized. Use of CSGM is enhanced by graphical displays of query results, which we describe as "circular viewer" and "search-within-results" functions. CSGM provides a virtual PCR representation (eHT-PCR) that predicts the specificity of each primer pair simultaneously in multiple genomes. CSGM Designer output was experimentally validated for the amplification of orthologous genes using 16 genotypes representing 12 crop and model legume species, distributed among the galegoid and phaseoloid clades. Successful cross-species amplification was obtained for 85.3% of PCR primer combinations.ConclusionCSGM Designer spans the divide between well-characterized crop and model legume species and their less well-characterized relatives. The outcome is PCR primers that target highly conserved genes for polymorphism discovery, enabling functional inferences and ultimately facilitating trait-associated molecular breeding

    Long term in vitro expansion of epithelial stem cells enabled by pharmacological inhibition of PAK1-ROCK-Myosin II and TGF-β signaling

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    Summary: Despite substantial self-renewal capability in vivo, epithelial stem and progenitor cells located in various tissues expand for a few passages in vitro in feeder-free condition before they succumb to growth arrest. Here, we describe the EpiX method, which utilizes small molecules that inhibit PAK1-ROCK-Myosin II and TGF-β signaling to achieve over one trillion-fold expansion of human epithelial stem and progenitor cells from skin, airway, mammary, and prostate glands in the absence of feeder cells. Transcriptomic and epigenomic studies show that this condition helps epithelial cells to overcome stresses for continuous proliferation. EpiX-expanded basal epithelial cells differentiate into mature epithelial cells consistent with their tissue origins. Whole-genome sequencing reveals that the cells retain remarkable genome integrity after extensive in vitro expansion without acquiring tumorigenicity. EpiX technology provides a solution to exploit the potential of tissue-resident epithelial stem and progenitor cells for regenerative medicine. : Zhang et al. screen a small-molecule collection and find that pharmacologic inhibition of TGF-β and PAK1-ROCK-Myosin II, in low calcium conditions, supports extended expansion of epithelial stem cells in 2D format. This approach enhances the potential of tissue-resident epithelial stem cells for cell therapy. Keywords: epithelial stem and progenitor cells, cell culture method, TGF-β, PAK1/ROCK/Myosin II, feeder-free, regenerative medicine, cell therap

    Lack of Association between Polymorphisms of the Dopamine Receptor D4 and Dopamine Transporter Genes and Personality Traits in a Korean Population

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    Human personality traits have a considerable genetic component. Cloninger et al. were the first to postulate that certain personality traits, such as novelty seeking, are related to the dopamine neurotransmitter system. In this study, we investigated the associations between dopamine receptor D4 (DRD4) exon III and dopamine transporter (DAT1) polymorphisms and personality traits. The DRD4 and DAT1 gene polymorphisms were genotyped in 214 healthy Korean subjects, whose personality traits were assessed with the Temperament and Character Inventory (TCI). There were no significant differences between scores of TCI temperament dimensions (novelty seeking, harm avoidance, reward dependence, and persistence) and DRD4 gene polymorphism. The DAT1 gene polymorphisms also showed no significant association with any of the temperament subscales of the TCI. These data suggest that DRD4 and DAT1 gene polymorphism may not associated with personality traits in a Korean population

    Voice interface responses based on prior user interactions

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    Voice interfaces, such as those provided by virtual assistant applications on smartphones, smart speakers, and other devices utilize natural language when providing responses to user queries. Per techniques of this disclosure, user interaction patterns are used to generate natural language responses to queries posed over a voice user interface. With user permission and express consent, data that pertain to prior user interaction, e.g., text entry such as search terms entered; other input operations such as clicks, taps, swipes, mouse hovers; viewports for the user, etc. are obtained. For ease of interaction, such permission is obtained, e.g., at initial setup, and is modifiable. Such data is analyzed to derive insight into context-based topics of interest to users. User preferences gathered across multiple contexts are utilized to generate natural language responses for voice-based user interaction
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