49 research outputs found

    Graph Distillation for Action Detection with Privileged Modalities

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    We propose a technique that tackles action detection in multimodal videos under a realistic and challenging condition in which only limited training data and partially observed modalities are available. Common methods in transfer learning do not take advantage of the extra modalities potentially available in the source domain. On the other hand, previous work on multimodal learning only focuses on a single domain or task and does not handle the modality discrepancy between training and testing. In this work, we propose a method termed graph distillation that incorporates rich privileged information from a large-scale multimodal dataset in the source domain, and improves the learning in the target domain where training data and modalities are scarce. We evaluate our approach on action classification and detection tasks in multimodal videos, and show that our model outperforms the state-of-the-art by a large margin on the NTU RGB+D and PKU-MMD benchmarks. The code is released at http://alan.vision/eccv18_graph/.Comment: ECCV 201

    Single Shot Temporal Action Detection

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    Temporal action detection is a very important yet challenging problem, since videos in real applications are usually long, untrimmed and contain multiple action instances. This problem requires not only recognizing action categories but also detecting start time and end time of each action instance. Many state-of-the-art methods adopt the "detection by classification" framework: first do proposal, and then classify proposals. The main drawback of this framework is that the boundaries of action instance proposals have been fixed during the classification step. To address this issue, we propose a novel Single Shot Action Detector (SSAD) network based on 1D temporal convolutional layers to skip the proposal generation step via directly detecting action instances in untrimmed video. On pursuit of designing a particular SSAD network that can work effectively for temporal action detection, we empirically search for the best network architecture of SSAD due to lacking existing models that can be directly adopted. Moreover, we investigate into input feature types and fusion strategies to further improve detection accuracy. We conduct extensive experiments on two challenging datasets: THUMOS 2014 and MEXaction2. When setting Intersection-over-Union threshold to 0.5 during evaluation, SSAD significantly outperforms other state-of-the-art systems by increasing mAP from 19.0% to 24.6% on THUMOS 2014 and from 7.4% to 11.0% on MEXaction2.Comment: ACM Multimedia 201

    Localizing the Common Action Among a Few Videos

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    This paper strives to localize the temporal extent of an action in a long untrimmed video. Where existing work leverages many examples with their start, their ending, and/or the class of the action during training time, we propose few-shot common action localization. The start and end of an action in a long untrimmed video is determined based on just a hand-full of trimmed video examples containing the same action, without knowing their common class label. To address this task, we introduce a new 3D convolutional network architecture able to align representations from the support videos with the relevant query video segments. The network contains: (\textit{i}) a mutual enhancement module to simultaneously complement the representation of the few trimmed support videos and the untrimmed query video; (\textit{ii}) a progressive alignment module that iteratively fuses the support videos into the query branch; and (\textit{iii}) a pairwise matching module to weigh the importance of different support videos. Evaluation of few-shot common action localization in untrimmed videos containing a single or multiple action instances demonstrates the effectiveness and general applicability of our proposal.Comment: ECCV 202

    Phase Diagram of Multilayer Magnetic Structures

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    Multilayer "ferromagnet-layered antiferromagnet" (Fe/Cr) structures frustrated due to the roughness of layer interfaces are studied by numerical modeling methods. The "thickness-roughness" phase diagrams for the case of thin ferromagnetic film on the surface of bulk antiferromagnet and for two ferromagnetic layers separated by an antiferromagnetic interlayer are obtained and the order parameter distributions for all phases are found. The phase transitions nature in such systems is considered. The range of applicability for the "magnetic proximity model" proposed by Slonczewski is evaluated.Comment: 8 pages, 8 figure

    The 2017 Terahertz Science and Technology Roadmap

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    Science and technologies based on terahertz frequency electromagnetic radiation (100GHz-30THz) have developed rapidly over the last 30 years. For most of the 20th century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to “real world” applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2016, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 17 sections that cover most of the key areas of THz Science and Technology. We hope that The 2016 Roadmap on THz Science and Technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies

    Strengthening study habits through information and communication technologies

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    El propósito de la investigación correspondió a fortalecer el hábito a través del mejoramiento de la lectoescritura a partir de las Tecnologías de Información y Comunicación como herramienta estratégica. Desde los procesos investigativo derivados de la integración de la Investigación como Estrategia Pedagógica. Metodológicamente la investigación es de tipo cuantitativo- descriptivo. La unidad de análisis estuvo constituida por 60 estudiantes pertenecientes a los grados tercero y quinto, entre las edades de 7 a 12 años. Los resultados derivados dan cuenta de los procesos de mejoramiento y fortalecimiento de los hábitos de estudio en los estudiantes involucrados en el proceso investigativo a través del uso de las TIC. A través del proceso investigativo se puede concluir que como estrategia de enseñanza aprendizaje es positivo la implementación de las TIC a fin de mejorar los resultados obtenidos por los estudiantes en las pruebas locales y nacionalesThe purpose of the research was to strengthen the habit through the improvement of literacy based on Information and Communication Technologies as a strategic tool. From the research processes derived from the integration of Research as a Pedagogical Strategy. Methodologically, the research is quantitative-descriptive. The analysis unit consisted of 60 students belonging to the third and fifth grades, between the ages of 7 to 12 years. The derived results show the processes of improvement and strengthening of study habits in students involved in the research process through the use of ICT. Through the research process it can be concluded that the implementation of ICTs is positive as a teaching-learning strategy in order to improve the results obtained by students in local and national test

    Noise mediated regularity of porous silicon nanostructures

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    Interaction of noise with nonlinear electrochemical kinetics involving the etching of porous silicon is studied experimentally. It is realized that by monotonically increasing the level of internal noise, one can tune the regularity of the spatial distribution of pores in silicon nanostructures. This regularity of the noise provoked structures is quantified using a spatial normalized variance technique in conjunction with the calculation of Hurst exponents. Our experimental results indicate the emergence of intrinsic coherence resonance. Consequently, there exists an optimal value of internal noise for which the spatial distribution of nanopores attain maximal regularity. This regularity of the pores can be useful for enhancing the optical response of porous silicon based devices
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