8 research outputs found
MIM-GAN-based Anomaly Detection for Multivariate Time Series Data
The loss function of Generative adversarial network(GAN) is an important
factor that affects the quality and diversity of the generated samples for
anomaly detection. In this paper, we propose an unsupervised multiple time
series anomaly detection algorithm based on the GAN with message importance
measure(MIM-GAN). In particular, the time series data is divided into
subsequences using a sliding window. Then a generator and a discriminator
designed based on the Long Short-Term Memory (LSTM) are employed to capture the
temporal correlations of the time series data. To avoid the local optimal
solution of loss function and the model collapse, we introduce an exponential
information measure into the loss function of GAN. Additionally, a discriminant
reconstruction score consisting on discrimination and reconstruction loss is
taken into account. The global optimal solution for the loss function is
derived and the model collapse is proved to be avoided in our proposed
MIM-GAN-based anomaly detection algorithm. Experimental results show that the
proposed MIM-GAN-based anomaly detection algorithm has superior performance in
terms of precision, recall, and F1 score.Comment: 7 pages,6 figure
Frost-Preventing Design for Space Station Refrigerator
Different preservation temperatures for sample storage in space stations and corresponding refrigerator devices have been designed. In the below-freezing environment, frost will occur on the inner wall surface and the sealing place of the refrigerator device, which may have an impact on the operating performance and sealing performance of the refrigerator device. This paper analyzes the impact of frost on refrigerator storage devices, and designs and verifies a scheme of air cooling with a hollow seal method to reduce the impact of frost. The designed refrigerator was tested for air cooling, sealing, and long-term performance. The tests show that the air-cooling structure designed in this paper can effectively reduce the frost on the sample surface. A cumulative helium mass spectrometry leak detection method is applied to verify that the hollow seal structure designed has a better sealing property, which can prevent the diffusion of water vapor and frosting at the sealing position. The design with air cooling and hollow sealing has less frost and more stable performance for long-term operation. The results demonstrate this refrigerator would have the capability of operating on-orbit. The frost-preventing method for space station refrigerator designed in this paper has significance for the design of similar cryogenic equipment in microgravity environments
Integrating answer set programming with semantic dictionaries for robot task planning
In this paper, we propose a novel integrated task planning system for service robots in domestic domains. Given open-ended high-level user instructions in natural language, robots need to generate a plan, i.e., a sequence of low-level executable actions, to complete the required tasks. To address this, we exploit the knowledge on semantic roles of common verbs defined in semantic dictionaries such as FrameNet and integrate it with Answer Set Programming — a task planning framework with both representation language and solvers. In the experiments, we evaluated our approach using common benchmarks on service tasks and showed that it can successfully handle much more tasks than the state-of-the-art solution. Notably, we deployed the proposed planning system on our service robot for the annual RoboCup@Home competitions and achieved very encouraging results
[Mn(PaPy2Q)(NO)]ClO4, a Near-Infrared Light activated release of Nitric Oxide drug as a nitric oxide donor for therapy of human prostate cancer cells in vitro and in vivo
This study was the first to investigate the synthesis of near-infrared light-sensitive NO prodrug [Mn(PaPy2Q)(NO)]ClO4, and detection the amount of NO released by the drug in different time and near infrared light (10Â mW, 20Â mW). It showed that with the increase of light power, the time required for the drug to release NO was shortened, and we selected 20Â mW, 10Â min as a follow-up study of light power and irradiation time while ensuring the near-infrared light did not affect tumor cells. The cells were irradiated with 20Â mW of near-infrared light for 10Â min at 6Â h after treatment with the drug on PC-3, LNCaP and 22RV1 cells, and NO concentration and cell survival rate were tested at 12Â h, 24Â h and 48Â h. Experiments showed that NO concentration remained stable within 48Â h and [Mn(PaPy2Q)(NO)]ClO4 inhibited the proliferation of cells in a concentration and time-dependent manner. Then we also found that [Mn(PaPy2Q)(NO)]ClO4 increased the expression of apoptosis-related proteins (PARP, Bax, Caspase 3/9), inhibited the expression of BCl-2 and increased the activity level of Caspase 3/7, which showed [Mn(PaPy2Q)(NO)]ClO4 promoted prostate cancer cells apoptosis. Next, the results in xenograft mouse model showed that [Mn(PaPy2Q)(NO)]ClO4 also had anti-prostate cancer effects in vivo, and the NO concentration increased in the tumor after near-infrared light irradiation. After [Mn(PaPy2Q)(NO)]ClO4 treatment 6 weeks, tumor volume was significantly reduced, Ki67 and BrdU protein expression was significantly reduced. TUNEL assay results showed that [Mn(PaPy2Q)(NO)]ClO4 could promote the apoptosis of solid tumors in vivo and in a concentration-dependent manner