Lifelong Classification in Open World With Limited Storage Requirements.

This letter focuses on the problem of lifelong classification in the open world, the goal of which is to achieve an endless process of learning. However, incremental data sets (like the streaming data) in the open world, where the new classes may be emerging, are unsuited for classical classification methods. For addressing this problem, existing methods usually retrain the whole observed data sets with the complex computation and the expensive storage cost. This letter attempts to improve the performance of classification in the open world and decomposes the problem into three subproblems: (1) to reject unknown instances, (2) to classify accepted instances, and (3) to cut the cost of learning. Rejecting unknown instances refers to recognize those instances whose classes are unknown according to the learner, which could reduce the computation of the retraining process and eliminate the storage of historical data sets. We employ outlier detection for rejecting instances and a variant artificial neural network for classifying with fewer weights. Results on several experiments show that the work is effective. Source code can be found at https://github.com/wangbi1988/Lifelong-learning-in-Open-World-Classification.

Preventive effect of bionic pulsed electromagnetic fields on bone mineral density / 第三军医大学学报

Objective To observe the short-term and long-term effect of preventive therapy of bionic pulsed electromagnetic fields(BEMF) on the osteoporosis model of Wistar rats.Methods Thirty-two 3-month-old female Wistar rats were randomly divided into 4 groups with 8 rats in each group: control group(group A),desamethasone group(group B),calcitonin group(group C) and BEMF group(group D).Rats in group A were raised normally and received normal saline.Rats in group B were injected with desamethasone only(1 mg/kg,intramuscularly,twice a week).Rats in group C were injected with calcitonin(2 IU/kg,subcutaneously,once a day) and rats in group D were irradiated with BEMF for preventive therapy,simultaneouly all rats were injected with desamethasone(1 mg/kg,intramuscularly,twice a week).The rat bone mineral density(BMD) was measured under narcosis at 4,8,12 weeks after starting preventive therapy.Results No significant differences in BMD were found among all groups 4 weeks later.The significant differences in BMD were observed between group D and group B 8 weeks later and lasted to 12 weeks(P