1,109 research outputs found

    Continual Contrastive Self-supervised Learning for Image Classification

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    For artificial learning systems, continual learning over time from a stream of data is essential. The burgeoning studies on supervised continual learning have achieved great progress, while the study of catastrophic forgetting in unsupervised learning is still blank. Among unsupervised learning methods, self-supervise learning method shows tremendous potential on visual representation without any labeled data at scale. To improve the visual representation of self-supervised learning, larger and more varied data is needed. In the real world, unlabeled data is generated at all times. This circumstance provides a huge advantage for the learning of the self-supervised method. However, in the current paradigm, packing previous data and current data together and training it again is a waste of time and resources. Thus, a continual self-supervised learning method is badly needed. In this paper, we make the first attempt to implement the continual contrastive self-supervised learning by proposing a rehearsal method, which keeps a few exemplars from the previous data. Instead of directly combining saved exemplars with the current data set for training, we leverage self-supervised knowledge distillation to transfer contrastive information among previous data to the current network by mimicking similarity score distribution inferred by the old network over a set of saved exemplars. Moreover, we build an extra sample queue to assist the network to distinguish between previous and current data and prevent mutual interference while learning their own feature representation. Experimental results show that our method performs well on CIFAR100 and ImageNet-Sub. Compared with the baselines, which learning tasks without taking any technique, we improve the image classification top-1 accuracy by 1.60% on CIFAR100, 2.86% on ImageNet-Sub and 1.29% on ImageNet-Full under 10 incremental steps setting

    Fabrication of a microresonator-fiber assembly maintaining a high-quality factor by CO2 laser welding

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    We demonstrate fabrication of a microtoroid resonator of a high-quality (high-Q) factor using femtosecond laser three-dimensional (3D) micromachining. A fiber taper is reliably assembled to the microtoroid using CO2 laser welding. Specifically, we achieve a high Q-factor of 2.12*10^6 in the microresonator-fiber assembly by optimizing the contact position between the fiber taper and the microtoroid.Comment: 7 pages, 5 figure

    Mutually-orthogonal unitary and orthogonal matrices

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    We introduce the concept of n-OU and n-OO matrix sets, a collection of n mutually-orthogonal unitary and real orthogonal matrices under Hilbert-Schmidt inner product. We give a detailed characterization of order-three n-OO matrix sets under orthogonal equivalence. As an application in quantum information theory, we show that the minimum and maximum numbers of an unextendible maximally entangled bases within a real two-qutrit system are three and four, respectively. Further, we propose a new matrix decomposition approach, defining an n-OU (resp. n-OO) decomposition for a matrix as a linear combination of n matrices from an n-OU (resp. n-OO) matrix set. We show that any order-d matrix has a d-OU decomposition. As a contrast, we provide criteria for an order-three real matrix to possess an n-OO decomposition.Comment: 16 pages, no figur

    Preliminary study of predation of the multi-colored lady beetle, Leis axyridis (Pallas), on two species of aphids

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    Adults of multi-colored lady beetle, Leis axyridis were starved for 24- hour, and allowed to prey on soybean aphid, Aphis glycines Matsumura, and corn leaf aphid, Rhopalosiphum maidis(Fitch) which were at various densities. By comparing and analyzing its predatory potential, we consider that both L. axyridis’ preying on A. glycines and on R. maidis were fitted with type II response, which can be simulated by Holling disc equation, and expressed as: Na 0.6792N/ (1 0.0022N) corn ? ? and Na 0.9463N/ (1 0.0023N) soybean ? ? , respectively. In addition, by comparing its functional parameters, we found that L. axyridis’ ability to control A. glycines is significantly stronger than that of R. maidis.Originating text in Chinese.Citation: Lin, Zhiwei, Wang, Liyan, Sun, Qiang, Nan, Shan. (1999). Preliminary study of predation of the multi-colored lady beetle, Leis axyridis (Pallas), on two species of aphids. Journal of Heilongjiang August First Land Reclamation University, 11(1), 26-28

    Taraxerol exerts potent anticancer effects via induction of apoptosis and inhibition of Nf-kB signalling pathway in human middle ear epithelial cholesteatoma cells

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    Purpose: To investigate the effect of taraxerol on the proliferation of middle ear epithelial cholesteatoma cells.Methods: The anti-proliferative effect of taraxerol was investigated by cell counting kit-8 (CCK8) and clonogenic assays. Apoptosis was measured using DAPI, while mitochondrial membrane potential was determined with the aid of rhodamine 123 staining. Protein expression was studied by western blotting.Results: Taraxerol induced concentration-dependent anti-proliferative effects on the middle ear epithelial cholesteatoma cells, and also inhibited their colony formation potential. The drug induced apoptosis in the middle ear epithelial cholesteatoma cells by reducing mitochondrial membrane potential, and also triggered sub-G1 cell cycle arrest in these cells. Moreover, taraxerol inhibited the expression of Nf-kB.Conclusion: These findings reveal that taraxerol may be a potential lead compound for the treatment of middle ear cholesteatoma.Keywords: Cholesteatoma, Epithelial tissues, Taraxerol, Apoptosis, Cell cycle arres
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