Do we really need temporal convolutions in action segmentation?

Action classification has made great progress, but segmenting and recognizing actions from long untrimmed videos remains a challenging problem. Most state-of-the-art methods focus on designing temporal convolution-based models, but the inflexibility of temporal convolutions and the difficulties in modeling long-term temporal dependencies restrict the potential of these models. Transformer-based models with adaptable and sequence modeling capabilities have recently been used in various tasks. However, the lack of inductive bias and the inefficiency of handling long video sequences limit the application of Transformer in action segmentation. In this paper, we design a pure Transformer-based model without temporal convolutions by incorporating temporal sampling, called Temporal U-Transformer (TUT). The U-Transformer architecture reduces complexity while introducing an inductive bias that adjacent frames are more likely to belong to the same class, but the introduction of coarse resolutions results in the misclassification of boundaries. We observe that the similarity distribution between a boundary frame and its neighboring frames depends on whether the boundary frame is the start or end of an action segment. Therefore, we further propose a boundary-aware loss based on the distribution of similarity scores between frames from attention modules to enhance the ability to recognize boundaries. Extensive experiments show the effectiveness of our model

Conjuntos excepcionais e alguns problemas de Mahler

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Matemática, 2017.Seja f uma função inteira e transcendente. Denotamos por Sf o conjunto de todos os α ∈ ´Q tais que f(α) ∈ ´Q (o conjunto excepcional de f). Nessa dissertação, mostraremos quais subconjuntos de ´Q podem ser o conjunto excepcional de alguma função inteira e transcendente. Além disso, trataremos de dois problemas de Mahler relacionados a propriedades de funções inteiras e transcendentes. Mostraremos que existem funções inteiras e transcendentes que levam um subconjunto dos números de Liouville nele mesmo e daremos uma resposta positiva ao Problema B de Mahler: Problema B: Existe uma função inteira e transcendente f(z) = Σn =0 ∞ a nz n com coeficientes racionais tal que f( ´Q ) ⊆ ´Q e f−1( ´Q ) ⊆ ´Q ? .Let f be an entire transcendental function. We denote by Sf the set of all α ∈ ´Q such that f(α) ∈ ´Q (exceptional set of f). Throughout this dissertation, we will show which subsets of ´Q can be the exceptional set of some entire transcendental function. Moreover, we will deal with two of Mahler’s problems related to properties of entire transcendental functions. We will show that there are entire transcendental functions that map a subset of Liouville numbers in itself and we will give a positive answer for Mahler’s Problem B: Problem B: Is there an entire transcendental function f(z) = Σn =0 ∞ a nz n with rational coefficients such that que f( ´Q ) ⊆ ´Q e f−1( ´Q ) ⊆ ´Q ?

A Numerical Analysis of Riveted Lap Joint Containing Multiple-site Damage

Abstract: The evaluation of stress intensity factors (SIFs) for cracks in mechanically fastened joints is one of the central issues in a damage tolerance analysis. Accurate stress intensity solutions may be difficult to determine due to geometric complexity along with variations in fastener load transfer and fastener interference and material thickness because of corrosion. Detailed finite element models that include specific aspects of fastener for lap joints analysis, but such representations are often impractical for large lap joints involving many fasteners. In order to reduce the number of degrees of freedom in a particular model, a methodology was implemented that efficiently depicts mechanical fasteners in lap joints using finite elements. Uncorroded and corroded lap joints with three crack scenarios were studied by the computationally efficient model. The effects of pillowing corrosion and fastener interference were also included in the model. The results show that the effect of MSD and thinning of the material is to increase substantially stress intensity factors (SIFs) values compare to that of a single crack without corrosion. For a given cyclic stress range, SIF decreases with increasing rivet interference level. This is particularly true for shorter crack lengths. SIF values for the longer crack are not sensitive to the length of shorter crack on the opposite side of the rivet hole. The effects of corrosion pillowing cause SIF values on the faying surface to be larger than those on the opposing surface, and the crack front distorts from the straight front. Moreover, stresses on the faying surface may exceed the yield strength of the material

Pepper root rot resistance and pepper yield are enhanced through biological agent G15 soil amelioration

Pepper root rot is a serious soil-borne disease that hinders pepper production, and efforts are being made to identify biological agents that can prevent and control pepper root rot. Our group recently discovered and produced a biological agent, named G15, which reduces the diversity and richness of fungi and bacteria when applied to pepper fields. In the soil of the G15-treatment condition, the pathogenic fungus Fusarium was inhibited, while the richness of beneficial bacteria Rhodanobacter was increased. Also, the ammonia nitrogen level was decreased in the G15-treatment soil, and the pH, total carbon, and total potassium levels were increased. Compared to the control condition, pepper yield was increased in the treatment group (by 16,680 kg acre−1). We found that G15 could alter the microbial community structure of the pepper rhizosphere. These changes alter the physical and chemical properties of the soil and, ultimately, improve resistance to pepper root rot and increase pepper yield

Characteristics of Pima pha-siRNAs.

<p>The distribution of p-value for Pima PYTs is shown in A, the classification of PYTs is shown in B, and the distribution of the 5’first nucleotide is shown in C. Auxin: auxin-related transcription factors; Other TF: other transcription factors; NBS: NBS-LRR disease resistance proteins; Repeat: repeat proteins; <i>TAS3</i>: <i>Arabidopsis TAS3</i> homologs; Enzymes: various enzymes; Predicted: predicted proteins; Uncharacterized: uncharacterized proteins.</p

Bioinformatics Analysis of Small RNAs in Pima (<i>Gossypium barbadense</i> L.)

<div><p>Small RNAs (sRNAs) are ~20 to 24 nucleotide single-stranded RNAs that play crucial roles in regulation of gene expression. In plants, sRNAs are classified into microRNAs (miRNAs), repeat-associated siRNAs (ra-siRNAs), phased siRNAs (pha-siRNAs), <i>cis</i> and <i>trans</i> natural antisense transcript siRNAs (<i>cis</i>- and <i>trans</i>-nat siRNAs). Pima (<i>Gossypium barbadense</i> L.) is one of the most economically important fiber crops, producing the best and longest spinnable fiber. Although some miRNAs are profiled in Pima, little is known about siRNAs, the largest subclass of plant sRNAs. In order to profile these gene regulators in Pima, a comprehensive analysis of sRNAs was conducted by mining publicly available sRNA data, leading to identification of 678 miRNAs, 3,559,126 ra-siRNAs, 627 pha-siRNAs, 136,600 <i>cis</i>-nat siRNAs and 79,994 <i>trans</i>-nat siRNAs. The 678 miRNAs, belonging to 98 conserved and 402 lineage-specific families, were produced from 2,138 precursors, of which 297 arose from introns, exons, or intron/UTR-exon junctions of protein-coding genes. Ra-siRNAs were produced from various repeat loci, while most (97%) were yielded from retrotransposons, especially LTRs (long terminal repeats). The genes encoding auxin-signaling-related proteins, NBS-LRRs and transcription factors were major sources of pha-siRNAs, while two conserved <i>TAS</i>3 homologs were found as well. Most <i>cis</i>-NATs in Pima overlapped in enclosed and convergent orientations, while a few hybridized in divergent and coincided orientations. Most <i>cis</i>- and <i>trans</i>-nat siRNAs were produced from overlapping regions. Additionally, characteristics of length and the 5’-first nucleotide of each sRNA class were analyzed as well. Results in this study created a valuable molecular resource that would facilitate studies on mechanism of controlling gene expression.</p></div

Characteristics of ra-siRNAs in <i>G</i>. <i>barbadense</i>.

<p>The length distribution of ra-siRNAs is shown in A, and the 5’first nucleotide of ra-siRNAs is shown in B. Transposon, retrotransposon, rRNA and simple repeat represent different derivations of ra-siRNAs.</p