1,721,104 research outputs found
AVocaDo: Strategy for Adapting Vocabulary to Downstream Domain
No full textDuring the fine-tuning phase of transfer learning, the pretrained vocabulary remains unchanged, while model parameters are updated. The vocabulary generated based on the pretrained data is suboptimal for downstream data when domain discrepancy exists. We propose to consider the vocabulary as an optimizable parameter, allowing us to update the vocabulary by expanding it with domain-specific vocabulary based on a tokenization statistic. Furthermore, we preserve the embeddings of the added words from overfitting to downstream data by utilizing knowledge learned from a pretrained language model with a regularization term. Our method achieved consistent performance improvements on diverse domains (i.e., biomedical, computer science, news, and reviews)
Aerodynamic Design of EAV Propeller using a Multi-Level Optimization Method
No full textA multi-level design optimization framework is developed for the aerodynamic design of EAV rotor blades and can be applied to any types of rotor blades during steady-state condition. An objective function is to enhance the aerodynamic performance of rotor blades by reducing the required power to counteract resultant torque and to increase structural safety. The optimization framework applies three-dimensional planform design and two-dimensional sectional design in a sequential and iterative manner. In the first-level planform design, we use a genetic algorithm and flow analysis based on computationally inexpensive blade element momentum theory (BEMT). An optimal planform shape is obtained with the relatively small number of design variables but with large variations. After the initial planform design is conducted, local flow conditions of the blade sections are analyzed using high-fidelity Navier-Stokes CFD flow solvers. Next, the sectional airfoil design is performed at several spanwise locations using a gradient-based optimization algorithm and Navier-Stokes flow analysis. When the optimal airfoil shape is determined throughout the span, the planform is redesigned given the new set of airfoil shapes. Through this iterative design process, not only an optimal flow condition but also an optimal shape of the EAV propeller blade is obtained. The optimized propeller-blade design was tested in a wind tunnel facility at various flow conditions to validate the design results. The efficiency was slightly less than the expected improvement of 9% predicted by our proposed design framework but still sufficiently enhanced the aerodynamic performance of the EAV rotor system
FIGURE 3 in Pseudoaliinostoc sejongens gen. & sp. nov. (Nostocales, Cyanobacteria) from floodplain soil of the Geum River in Korea based on polyphasic approach
No full textFIGURE 3. Alignment of the 16S–23S rRNA internal transcribed spacer (ITS) region from Nostoc sp., Aliinostoc morphoplasticum, and Pseudoaliinostoc sejongens. Different conserved domains (D1–D5), tRNA genes, major variable stems V2 and V3, and antiterminator (Box- B and Box-A) are indicated by boxes and names. Nostoc and P. sejongens contain both tRNAIle and tRNAAla, whereas A. morphoplasticum does not have tRNAIle. All compared sequences contain important structural elements of the ITS as described by Boyer et al. (2001).Published as part of Lee, Nam-Ju, Bang, Sung-Do, Kim, Taehee, Ki, Jang-Seu & Lee, Ok-Min, 2021, Pseudoaliinostoc sejongens gen. & sp. nov. (Nostocales, Cyanobacteria) from floodplain soil of the Geum River in Korea based on polyphasic approach, pp. 55-70 in Phytotaxa 479 (1) on page 62, DOI: 10.11646/phytotaxa.479.1.4, http://zenodo.org/record/541338
FIGURE 2 in Porphyrosiphon annulatus sp. nov. (Oscillatoriales, Cyanobacteria) isolated on moist soil in Suwon, Republic of Korea
No full textFIGURE 2. Microphotographs of Porphyrosiphon annulatus the raw (A–C) and culture samples (D–J) from the reference strain (FBCC-A260). (A–B) Yellowish-brown and blue-green filaments, (C) Transversely annular lamellations in the sheath (arrow), (D) Colony of trichomes (sheath initially colorless and later yellow-brown or pink), (E, F) Longitudinal lamellations in the sheath (arrow), (G–I) Transversely annular lamellations in the sheath (arrows), (J) Two trichomes within a sheath; Scale bars = (A–C, E–J) 10 µm, (D) 50 µm.Published as part of Kim, Do-Hyun, Lee, Nam-Ju, Yoon, Sung-Ro, Kim, Taehee, Ki, Jang-Seu & Lee, Ok-Min, 2022, Porphyrosiphon annulatus sp. nov. (Oscillatoriales, Cyanobacteria) isolated on moist soil in Suwon, Republic of Korea, pp. 288-300 in Phytotaxa 532 (3) on page 291, DOI: 10.11646/phytotaxa.532.3.6, http://zenodo.org/record/596471
Enhancement of the cyclic stability of a Li-excess layered oxide through a simple electrode treatment for LiF-coating
No full textLithium-rich layered cathodes (LLCs) are considered to be promising next-generation materials for lithium-ion batteries (LIBs) due to their high specific capacity and energy density. However, their poor cyclability poses a significant challenge for commercial applications. In this study, we introduce a straightforward one-step electrode heat-treatment method involving a lithium fluoride (LiF) coating on conventional LLCs, without the need for additional coating precursors, to enhance the cyclability. During the heat-treatment, lithium residues (LiOH and Li2CO3) and the PVDF used as a binder react to form an amorphous LiF coating layer (LiF-LLC). Although LiFLLC initially exhibited a lower capacity compared to pristine LLC (220.2 vs. 246.6 mAh g-1) due to its higher overpotential, it demonstrated superior performance after 100 cycles at 0.2 C. LiF-LLC maintained a discharge capacity of 219.4 mAh g-1 with 95.1 % retention, while pristine LLC showed an outcome of only 164.8 mAh g-1 with 83.4 % retention. A comprehensive analysis revealed that the LiF coating layer effectively passivated the cathode interface, preventing transition metal dissolution and a phase transformation caused by a HF attack. Additionally, LiF-LLC exhibited higher lithium-ion diffusivity, lower interfacial impedance, and enhanced Mnand O-ion redox activities. These findings demonstrate that the simple electrode heat-treatment significantly improves the cyclic stability of LLCs.
Design Analysis of Precision Navigation System
No full textAs GNSS(Global Navigation Satellite System) is becoming more common all over the world, the satellite navigation system is used in many fields such as positioning, navigation, timing, land survey, and so on. The satellite navigation covers all around world and can be used in everywhere if the satellite signal could be received. But the performance of positioning has the limitation due to the way of satellite navigation. The satellite navigation system has the error elements which are ionospheric delay, tropospheric delay, orbit ephemeris error, and other errors in calculation of positioning. These error elements degrade the positioning accuracy and the reliability of satellite navigation system. If these problems which make the usage of satellite navigation system be limited are resolved, the usage will be extended more than present. ETRI(Electronics and Telecommunications Research Institute) is developing precision navigation system for sub-centimeter positioning. This system is for providing precision navigation service and securing the application technology in satellite navigation system. This technology has important point in future navigation market and application. In this paper, we introduce the precision navigation system and design process. The navigation algorithm to be applied in the system is analyzed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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