543 research outputs found

    Self Attention with Temporal Prior: Can We Learn More from Arrow of Time?

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    Many of diverse phenomena in nature often inherently encode both short and long term temporal dependencies, short term dependencies especially resulting from the direction of flow of time. In this respect, we discovered experimental evidences suggesting that {\it interrelations} of these events are higher for closer time stamps. However, to be able for attention based models to learn these regularities in short term dependencies, it requires large amounts of data which are often infeasible. This is due to the reason that, while they are good at learning piece wised temporal dependencies, attention based models lack structures that encode biases in time series. As a resolution, we propose a simple and efficient method that enables attention layers to better encode short term temporal bias of these data sets by applying learnable, adaptive kernels directly to the attention matrices. For the experiments, we chose various prediction tasks using Electronic Health Records (EHR) data sets since they are great examples that have underlying long and short term temporal dependencies. The results of our experiments show exceptional classification results compared to best performing models on most of the task and data sets

    Robust optimization utilizing the second-order design sensitivity information

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    This paper presents an effective methodology for robust optimization of electromagnetic devices. To achieve the goal, the method improves the robustness of the minimum of the objective function chosen as a design solution by minimizing the second-order sensitivity information, called a gradient index (GI) and defined by a function of gradients of performance functions with respect to uncertain variables. The constraint feasibility is also enhanced by adding a GI corresponding to the constraint value. The distinctive feature of the method is that it requires neither statistical information on design variables nor calculation of the performance reliability during the robust optimization process. The validity of the proposed method is tested with the TEAM Workshop Problem 2

    Magnon topology and thermal Hall effect in trimerized triangular lattice antiferromagnet

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    The non-trivial magnon band topology and its consequent responses have been extensively studied in two-dimensional magnetisms. However, the triangular lattice antiferromagnet (TLAF), the best-known frustrated two-dimensional magnet, has received less attention than the closely related Kagome system, because of the spin-chirality cancellation in the umbrella ground state of the undistorted TLAF. In this work, we study the band topology and the thermal Hall effect (THE) of the TLAF with (anti-)trimerization distortion under the external perpendicular magnetic field using the linearized spin wave theory. We show that the spin-chirality cancellation is removed in such case, giving rise to the non-trivial magnon band topology and the finite THE. Moreover, the magnon bands exhibit band topology transitions tuned by the magnetic field. We demonstrate that such transitions are accompanied by the logarithmic divergence of the first derivative of the thermal Hall conductivity. Finally, we examine the above consequences by calculating the THE in the hexagonal manganite YMnO3_3, well known to have anti-trimerization.Comment: 6 + 7 pages, 3 + 5 figures, 0 + 1 table; Journal reference adde

    IT Capabilities, Process-Oriented Dynamic Capabilities, and Firm Financial Performance

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    More and more publications are highlighting the value of IT in affecting business processes. Recognizing firm-level dynamic capabilities as key to improved firm performance, our work examines and empirically tests the influencing relationships among IT capabilities (IT personnel expertise, IT infrastructure flexibility, and IT management capabilities), process-oriented dynamic capabilities, and financial performance. Process-oriented dynamic capabilities are defined as a firm’s ability to change (improve, adapt, or reconfigure) a business process better than the competition in terms of integrating activities, reducing cost, and capitalizing on business intelligence/learning. They encompass a broad category of changes in the firm’s processes, ranging from continual adjustments and improvements to radical one-time alterations. Although the majority of changes may be incremental, a firm’s capacity for timely changes also implies its readiness to execute radical alterations when the need arises. Grounded on the theoretical position, we propose a research model and gather a survey data set through a rigorous process that retains research validity. From the analysis of the survey data, we find an important route of causality, as follows: IT personnel expertise -\u3e IT management capabilities -\u3e IT infrastructure flexibility -\u3e process-oriented dynamic capabilities -\u3e financial performance. Based on this finding, we discuss the main contributions of our study in terms of the strategic role of IT in enhancing firm performance

    カンコク ヘナム グン ノ ベイサク ノウカ ニ オケル キコウ ヘンドウ ノ ニンシキ ニ カンスル ブンセキ

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    本研究では韓国ヘナム郡の米作農家における気候変動の認識に関して分析した。ロジットモデルとプロビットモデルを用いて、気候変動の認識の決定要素を検定した。結果として、米作農家の気候変動の認識は高いこと(83.6%)が示された。年齢については負の値であり、高齢者であるほど認識が少ない。つまり若年層が強く気候変動を認識していた。教育については正の値であり、高学歴であるほど強く気候変動を認識していた。そして気候情報の入手については正の値であり、情報アクセスを改善することによって、強く気候変動を認識させることができると分かった。本研究から気候変動情報、教育、訓練における適切な政策プログラムが提供される。This study analyzes perception to climate change of rice farmers in Haenam district, Korea. A logit model and a probit model are used to examine the determinants of perception to climate change. The results indicate that rice farmers\u27 perception of climate change appear to be high(83.6 percent). The findings indicate that age, education and access to climate information have a significant impact on perception to climate change. This study provides some appropriate policy program of information on climate change, education and training

    Antioxidant compounds from marine seaweeds and their mechanism of action

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    Investigation of natural products has moved toward marine environments as they are a source of many biologically active agents. The natural antioxidant compounds isolated from seaweeds provide a valuable contribution to the innovation of new drugs for chronic diseases associated with oxidative stress. While the antioxidant activity and nutritional benefits of various seaweed products are well recognized, their proper utilization as antioxidants remains at initial stages that require further investigative studies. This review provides a detailed study of isolated antioxidant compounds from seaweeds and their major mechanism of action by focusing on the reports from 2015 to 2019. The report discusses various active antioxidant compounds, including phenolics (e.g., phlorotannins), polysaccharides, and pigments with proven benefits against oxidative stress-related diseases, especially carotenoids, from the aspect of benefits to human health

    Endoscopic Submucosal Dissection of Gastric Epithelial Neoplasms after Partial Gastrectomy: A Single-Center Experience

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    Aims. To investigate the feasibility and safety of endoscopic submucosal dissection (ESD) of gastric epithelial neoplasms in the remnant stomach (GEN-RS) after various types of partial gastrectomy. Methods. This study included 29 patients (31 lesions) who underwent ESD for GEN-RS between March 2006 and August 2016. Clinicopathologic data were retrieved retrospectively to assess the therapeutic ESD outcomes, including en bloc and complete resection rates and procedure-related adverse events. Results. The en bloc, complete, and curative resection rates were 90%, 77%, and 71%, respectively. The types of previous gastrectomy, tumor size, macroscopic type, and tumor histology were not associated with incomplete resection. Only tumors involving the suture lines from the prior partial gastrectomy were significantly associated with incomplete resection. The procedure-related bleeding and perforation rates were 6% and 3%, respectively; none of the adverse events required surgical intervention. During a median follow-up period of 25 months (range, 6–58 months), there was no recurrence in any case. Conclusions. ESD is a safe and feasible treatment for GEN-RS regardless of the previous gastrectomy type. However, the complete resection rate decreases for lesions involving the suture lines
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