While machine translation for spoken language has advanced significantly, research on sign language translation (SLT) for deaf individuals remains limited. Obtaining annotations, such as gloss, can ...be expensive and time-consuming. To address these challenges, we propose a new sign language video-processing method for SLT without gloss annotations. Our approach leverages the signer's skeleton points to identify their movements and help build a robust model resilient to background noise. We also introduce a keypoint normalization process that preserves the signer's movements while accounting for variations in body length. Furthermore, we propose a stochastic frame selection technique to prioritize frames to minimize video information loss. Based on the attention-based model, our approach demonstrates effectiveness through quantitative experiments on various metrics using German and Korean sign language datasets without glosses.
A new analysis methodology for millimeter-wave stacked-FET power amplifier design is proposed with a focus on the output power improvement by adjusting the complex load-admittance of each ...stacked-transistor. From this analysis, it is shown that there exist fundamental limitations on the maximum FET-stacking number and the operation frequency with given FET characteristics. Moreover, comprehensive analysis is performed to understand the effect of each FET parameter in limiting the number of stacks and output power. Based on this, a simple design method of C gs compensation is proposed to further increase the number of the stacks and enhance the output power. To verify analyses, various high-frequency stacked-FET PA MMICs are designed and fabricated at different frequencies with pHEMTs, mHEMTs, and CMOSFETs, which all have different maximum transition frequencies ( f T's). This paper presents comprehensive analysis to identify the limitation of the stacked-FET amplifiers at millimeter-wave frequencies and presents a new design methodology to further improve the output power performance at high frequencies.
We report the electrocatalytic oxidation of ethylene glycol and glycerol in alkaline media over PtAg nanotubes (PtAgNTs), which were prepared through the partial galvanic exchange of Pt on Ag ...nanowires. The PtAgNTs demonstrated substantially enhanced electrocatalytic performance compared with Pt nanotubes and commercial Pt black and Pt/C catalysts as evidenced by their higher peak current densities, lower onset potentials and better anti-poisoning properties, which originated from the tailored geometric and electronic structures of the PtAgNTs.
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•PtAg nanotubes (PtAgNTs) were prepared via a simple galvanic exchange method.•The PtAgNTs showed high activity for EG and Gly oxidation in alkaline media.•The activity enhancement arose from the structural and electronic effects.
A new chemical dual-functional reducing agent, thiophene, was used to produce high-quality reduced graphene oxide (rGO) as a result of a chemical reduction of graphene oxide (GO) and the healing of ...rGO. Thiophene reduced GO by donation of electrons with acceptance of oxygen while it was converted into an intermediate oxidised polymerised thiophene that was eventually transformed into polyhydrocarbon by loss of sulphur atoms. Surprisingly, the polyhydrocarbon template helped to produce good-quality rGOC (chemically reduced) and high-quality rGOCT after thermal treatment. The resulting rGOCT nanosheets did not contain any nitrogen or sulphur impurities, were highly deoxygenated and showed a healing effect. Thus the electrical properties of the as-prepared rGOCT were superior to those of conventional hydrazine-produced rGO that require harsh reaction conditions. Our novel dual reduction and healing method with thiophene could potentially save energy and facilitate the commercial mass production of high-quality graphene.
In search of a molecular receptor that could bind fluoride ions in water below the maximum contaminant level of 4 ppm set by the Environmental Protection Agency (EPA), we have investigated the water ...stability and fluoride binding properties of a series of phosphonium boranes of general formula p-(Mes2B)C6H4(PPh2R)+ with R = Me (1+), Et (2+), n-Pr (3+), and Ph (4+). These phosphonium boranes are water stable and react reversibly with water to form the corresponding zwitterionic hydroxide complexes of general formula p-(Mes2(HO)B)C6H4(PPh2R). They also react with fluoride ions to form the corresponding zwitterionic fluoride complexes of general formula p-(Mes2(F)B)C6H4(PPh2R). Spectrophotometric acid−base titrations carried out in H2O/MeOH (9:1 vol.) afford pK R+ values of 7.3(±0.07) for 1+, 6.92(±0.1) for 2+, 6.59(±0.08) for 3+, and 6.08(±0.09) for 4+, thereby indicating that the Lewis acidity of the cationic boranes increases in following order: 1+ < 2+ < 3+ < 4+. In agreement with this observation, fluoride titration experiments in H2O/MeOH (9:1 vol.) show that the fluoride binding constants (K = 840(±50) M−1 for 1+, 2500(±200) M−1 for 2+, 4000(±300) M−1 for 3+, and 10 500(±1000) M−1 for 4+) increase in the same order. These results show that the Lewis acidity of the cationic boranes increases with their hydrophobicity. The resulting Lewis acidity increase is substantial and exceeds 1 order of magnitude on going from 1+ to 4+. In turn, 4+ is sufficiently fluorophilic to bind fluoride ions below the EPA contaminant level in pure water. These results indicate that phosphonium boranes related to 4+ could be used as molecular recognition units in chemosensors for drinking water analysis.
Parcel storage provides last-mile delivery services as part of the logistics process. In order to build an intelligent system for parcel storage, we conducted a study on parcel box recognition using ...AI’s deep learning technology. Box detection and location estimation studies were conducted using the YOLOv5 model for parcel recognition, and this model is presently being applied to many studies because it has excellent object recognition and is faster than previous models. The YOLOv5 model is classified into small, medium, large, and xlarge according to the size and performance of the model. In this study, these four models were compared and analyzed to perform an experiment showing the optimal parcel box recognition performance. As a result of the experiment, it was determined that the precision, recall, and F1 of the YOLOv5large model were 0.966, 0.899, and 0.932, respectively, showing a stronger performance than the other models. Additionally, the size of the YOLOv5large is half that of YOLOv5xlarge, and the YOLOv5large showed the optimal performance in object recognition of the parcel box. Therefore, it seems that the basis for building an intelligent parcel storage system, which shows optimal efficiency in real time using the YOLOv5large model, can be laid through the parcel object recognition experiment conducted in this study.
Realization of devices with enhanced stretchability and waterproof properties will significantly expand the reach of electronics. To this end, we herein fabricate an elastic transparent conductor ...that comprises silver nanowires (AgNWs) on a hydroxylated polydimethylsiloxane (PDMS) substrate covered by polyurethane urea (PUU), which is fully compatible with both materials. Carboxylic acid groups of PUU was designed to form hydrogen bonds with the carbonyl groups of poly(vinylpyrrolidone) on the AgNW surface, resulting in an enhanced affinity of AgNWs for PUU. Exceptionally strong hydrogen bonds between PUU and the hydroxylated PDMS thus facilitate the achievement of water sealable, mechanically stable, and stretchable transparent electrodes. To fabricate stretchable electroluminescence (EL) devices, ZnS particles were mixed with PUU, and the mixture was coated onto the AgNWs/hydroxylated PDMS, followed by a face-to-face lamination with another identical electrode. The devices could be stretched up to 150% without a severe reduction in the emission intensity, and they survived 5000 cycles of 100% stretch–release testing. The high adhesion between PUU and PDMS even in water is responsible for the good waterproof characteristics of the EL devices. These results pave the way for realization of fully stretchable and waterproof electronic devices.
New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong ...acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor.
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