分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Astronomical outliers, such as unusual, rare or unknown types of astronomical objects or phenomena, constantly lead to the discovery of genuinely unforeseen knowledge in astronomy. More unpredictable outliers will be uncovered in principle with the increment of the coverage and quality of upcoming survey data. However, it is a severe challenge to mine rare and unexpected targets from enormous data with human inspection due to a significant workload. Supervised learning is also unsuitable for this purpose since designing proper training sets for unanticipated signals is unworkable. Motivated by these challenges, we adopt unsupervised machine learning approaches to identify outliers in the data of galaxy images to explore the paths for detecting astronomical outliers. For comparison, we construct three methods, which are built upon the k-nearest neighbors (KNN), Convolutional Auto-Encoder (CAE)+ KNN, and CAE + KNN + Attention Mechanism (attCAE KNN) separately. Testing sets are created based on the Galaxy Zoo image data published online to evaluate the performance of the above methods. Results show that attCAE KNN achieves the best recall (78%), which is 53% higher than the classical KNN method and 22% higher than CAE+KNN. The efficiency of attCAE KNN (10 minutes) is also superior to KNN (4 hours) and equal to CAE+KNN(10 minutes) for accomplishing the same task. Thus, we believe it is feasible to detect astronomical outliers in the data of galaxy images in an unsupervised manner. Next, we will apply attCAE KNN to available survey datasets to assess its applicability and reliability.
分类： 心理学 >> 认知心理学 提交时间： 2020-02-05
摘要： BACKGROUND: Saccade-induced retrieval enhancement (SIRE) refers to the phenomenon that active engaging of horizontal eye movements before recall would enhance subsequent memory performance. This effect is generally thought to be the result of interhemispheric interaction stimulated by saccades. Nonetheless, recent findings do not fully support this hypothesis. An alternative explanation is that saccades promote memory retrieval by improving top-down attention control. Thus, the mechanisms of SIRE are unclear, the present meta-analysis quantitatively analyzed the effect of saccades on memory performance and examined the mechanisms of SIRE through moderator analysis. METHODS: We searched "Web of Science", "PubMed", and "Springer" for peer reviewed papers using the keywords "eye movements + memory" and "saccades + memory". Twenty-two papers were included in the final analysis. RESULTS: There was a significant facilitation of horizontal saccades on overall memory performance, with a pooled effect size (Cohen’s d) of 0.45 (p < 0.001). However, the overall effect of vertical saccades was not significant (d = 0.1, p = 0.14). Moderation analysis showed that the handedness of participants was a significant moderator of the SIRE, with strongly right-handed individuals benefited more from horizontal saccades than non-strongly right-handed individuals (p < 0.01). CONCLUSION: Horizontal saccades improved memory performances, particularly for the strongly right-handed individuals, these results support the interhemispheric interaction hypothesis.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
JUNO Collaboration
Jie Zhao
Baobiao Yue
Haoqi Lu
Yufeng Li
Jiajie Ling
Zeyuan Yu
Angel Abusleme
Thomas Adam
Shakeel Ahmad
Rizwan Ahmed
Sebastiano Aiello
Muhammad Akram
Abid Aleem
Tsagkarakis Alexandros
Fengpeng An
Qi An
Giuseppe Andronico
Nikolay Anfimov
Vito Antonelli
摘要： The physics potential of detecting $^8$B solar neutrinos is exploited at the Jiangmen Underground Neutrino Observatory (JUNO), in a model independent manner by using three distinct channels of the charged-current (CC), neutral-current (NC) and elastic scattering (ES) interactions. Due to the largest-ever mass of $^{13}$C nuclei in the liquid-scintillator detectors and the potential low background level, $^8$B solar neutrinos would be observable in the CC and NC interactions on $^{13}$C for the first time. By virtue of optimized event selections and muon veto strategies, backgrounds from the accidental coincidence, muon-induced isotopes, and external backgrounds can be greatly suppressed. Excellent signal-to-background ratios can be achieved in the CC, NC and ES channels to guarantee the $^8$B solar neutrino observation. From the sensitivity studies performed in this work, we show that one can reach the precision levels of 5%, 8% and 20% for the $^8$B neutrino flux, $\sin^2\theta_{12}$, and $\Delta m^2_{21}$, respectively, using ten years of JUNO data. It would be unique and helpful to probe the details of both solar physics and neutrino physics. In addition, when combined with SNO, the world-best precision of 3% is expected for the $^8$B neutrino flux measurement.
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