分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2022-11-28 合作期刊: 《数据智能（英文）》
摘要：Due to the large-scale spread of COVID-19, which has a significant impact on human health and social economy, developing effective antiviral drugs for COVID-19 is vital to saving human lives. Various biomedical associations, e.g., drug-virus and viral protein-host protein interactions, can be used for building biomedical knowledge graphs. Based on these sources, large-scale knowledge reasoning algorithms can be used to predict new links between antiviral drugs and viruses. To utilize the various heterogeneous biomedical associations, we proposed a fusion strategy to integrate the results of two tensor decomposition-based models (i.e., CP-N3 and ComplEx-N3). Sufficient experiments indicated that our method obtained high performance (MRR=0.2328). Compared with CP-N3, the mean reciprocal rank (MRR) is increased by 3.3% and compared with ComplEx-N3, the MRR is increased by 3.5%. Meanwhile, we explored the relationship between the performance and relationship types, which indicated that there is a negative correlation (PCC=0.446, P-value=2.26e-194) between the performance of triples predicted by our method and edge betweenness.
分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2022-11-27 合作期刊: 《数据智能（英文）》
摘要：Knowledge graph (KG) completion aims at filling the missing facts in a KG, where a fact is typically represented as a triple in the form of (head, relation, tail). Traditional KG completion methods compel two#2;thirds of a triple provided (e.g., head and relation) to predict the remaining one. In this paper, we propose a new method that extends multi-layer recurrent neural networks (RNNs) to model triples in a KG as sequences. It obtains state-of-the-art performance on the common entity prediction task, i.e., giving head (or tail) and relation to predict the tail (or the head), using two benchmark data sets. Furthermore, the deep sequential characteristic of our method enables it to predict the relations given head (or tail) only, and even predict the whole triples. Our experiments on these two new KG completion tasks demonstrate that our method achieves superior performance compared with several alternative methods.
分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2022-11-27 合作期刊: 《数据智能（英文）》
摘要：The Chinese Software Developer Network (CSDN) is one of the largest information technology communities and service platforms in China. This paper describes the user profiling for CSDN, an evaluation track of SMP Cup 2017. It contains three tasks: (1) user document keyphrase extraction, (2) user tagging and (3) user growth value prediction. In the first task, we treat keyphrase extraction as a classification problem and train a Gradient-Boosting-Decision-Tree model with comprehensive features. In the second task, to deal with class imbalance and capture the interdependency between classes, we propose a two-stage framework: (1) for each class, we train a binary classifier to model each class against all of the other classes independently; (2) we feed the output of the trained classifiers into a softmax classifier, tagging each user with multiple labels. In the third task, we propose a comprehensive architecture to predict user growth value. Our contributions in this paper are summarized as follows: (1) we extract various types of features to identify the key factors in user value growth; (2) we use the semi-supervised method and the stacking technique to extend labeled data sets and increase the generality of the trained model, resulting in an impressive performance in our experiments. In the competition, we achieved the first place out of 329 teams.
分类： 信息科学与系统科学 >> 控制科学与技术 分类： 计算机科学 >> 计算机应用技术 提交时间： 2022-04-20
Process industry is the pillar industry of national economy, particularly, the process of producing magnesia by fused magnesia furnace system is a typical category of process industry. Due to the complex smelting mechanism and changing production factors, abnormal working conditions often occur in fused magnesia furnace. The semi-molten condition is the most typical and harmful abnormal condition. In this paper, an adaptive pretraining-inference-dynamic training-validation semantic segmentation method based on industrial video is proposed for dynamic prediction of semi-molten condition of multiple fused magnesium furnaces. The experimental results show that compared with the prediction model without adaptive learning, the prediction performance of the adaptive learning model in this paper for multiple fused magnesium melting processes is significantly improved.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2021-12-31 合作期刊: 《Nuclear Science and Techniques》
摘要：Controllable D-D neutron sources have a long service life, low cost, and non-radioactivity. There are favorable prospects for its application in geophysical well logging, since traditional chemical radioactive sources used for well logging pose potential threats to the safety of the human body and environment. This paper presents an improved method to measure formation density that employs a D-D neutron source. In addition, the lithological effect on the measured density was removed to better estimate the formation porosity. First, we investigated the spatial distribution of capture gamma rays through Monte Carlo simulations as well as the relationship between the ratio of capture gamma ray counts and formation density to establish theoretical support for the design of density logging tools and their corresponding data processing methods. Second, we obtained the far to near detector counts of captured gamma rays for an optimized tool structure, and then established its correlation with the density and porosity of three typical formations with pure quartz, calcite, and dolomite minerals. Third, we determined the values for correcting the densities of sandstone and dolomite with the same porosity using limestone data as the reference and established the equations for calculating the correction values, which lays a solid foundation for accurately calculating formation porosity. We observed that the capture gamma ray counts first increased then decreased and varied in different formations; this was especially observed in high-porosity formations. Under the same lithologic conditions (rock matrix), as the porosity increases, the peak value of gamma ray counts moves toward the neutron source. At different detector-source distances, the ratio of the capture gamma ray counts was well correlated with the formation density. An equation of the formation density conversion was established based on the ratio of capture gamma ray counts at the detector-source distances of 30 cm and 65 cm, and the calculated values were consistent with the true values. After correction, the formation density was highly consistent with the true value of the limestone density, and the mean absolute error was -0.013 g/cm3. The calculated porosity values were very close to the true values, and the mean relative error was 2.33%, highlighting the accuracy of the proposed method. These findings provide a new method for developing D-D neutron source logging tools and their well-log data processing methods.
分类： 地球科学 >> 地理学 提交时间： 2019-01-17 合作期刊: 《干旱区科学》
摘要： Snowfall is one of the dominant water resources in the mountainous regions and is closely related to the development of the local ecosystem and economy. Snowfall predication plays a critical role in understanding hydrological processes and forecasting natural disasters in the Tianshan Mountains, where meteorological stations are limited. Based on climatic, geographical and topographic variables at 27 meteorological stations during the cold season (October to April) from 1980 to 2015 in the Tianshan Mountains located in Xinjiang of Northwest China, we explored the potential influence of these variables on snowfall and predicted snowfall using two methods: multiple linear regression (MLR) model (a conventional measuring method) and random forest (RF) model (a non-parametric and non-linear machine learning algorithm). We identified the primary influencing factors of snowfall by ranking the importance of eight selected predictor variables based on the relative contribution of each variable in the two models. Model simulations were compared using different performance indices and the results showed that the RF model performed better than the MLR model, with a much higher R2 value (R2=0.74; R2, coefficient of determination) and a lower bias error (RSR=0.51; RSR, the ratio of root mean square error to standard deviation of observed dataset). This indicates that the non-linear trend is more applicable for explaining the relationship between the selected predictor variables and snowfall. Relative humidity, temperature and longitude were identified as three of the most important variables influencing snowfall and snowfall prediction in both models, while elevation, aspect and latitude were of secondary importance, followed by slope and wind speed. These results will be beneficial to understand hydrological modeling and improve management and prediction of water resources in the Tianshan Mountains.
分类： 天文学 >> 天文学 提交时间： 2018-05-28 合作期刊: 《天文研究与技术》
This paper is aimed at separation treatment of low- and high-frequency components in polar motion forecasting and thenimproving time-series predictions. For the purpose, the empirical mode decomposition (EMD) is employed as a filter to extract low- and high-frequency signals from original pole coordinate data. The decomposition of the pole motion observations between 1986 and 2015 from the International Earth Rotation and Reference Systems Service (IERS) C04 seriesillustrates that the low-frequency fluctuations including inter-decadal, inter-annual, Chandler and annual wobbles and shorter-period high-frequency oscillationscan be separated from the observed time-series by the EMD. On the basis of separation, the least-squares (LS) extrapolation of models for annual and Chandler wobbles and for the linear trend are used for deterministic prediction of the low-frequency fluctuations, while the autoregressive (AR) technology is applied to forecasting the high-frequency oscillations plus LS fitting residuals. Pole coordinateforecasts are calculated as the sum of LS extrapolation and AR predictions (LS+AR).We have evaluated the accuracy of our long-term predictions (up to 1 year in the future) in comparison with the IERS official predictions in terms of year-by-year statistics of 5 years. It is shown that the accuracy of the LS+AR methodcan be significantly improved using a combination of the EMD and LS+AR (EMD+LS+AR). Also, the proposed prediction strategyoverall outperforms the IERS solutions. In addition, the predictions are compared with those from the Earth Orientation Parameters Prediction Comparison Campaign (EOP PCC). The comparison demonstrates that the developed schemeis a very accurate approach to predict polar motion. According to this study, it is concluded that polar motion predictions may be enhanced through separation treatment of different time-scale fluctuations and thus such processing seems to be necessary in pole coordinate prediction.
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要：In this work, the photovoltaic properties of BFBPD-PC61BM system as a promising high-performance organic solar cell (OSC) were theoretically investigated by means of quantum chemistry and molecular dynamics calculations coupled with the incoherent charge-hopping model. Moreover, the hole carrier mobility of BFBPD thin-film was also estimated with the aid of an amorphous cell including 100 BFBPD molecules. Results revealed that the BFBPD-PC61BM system possesses a middle-sized open-circuit voltage of 0.70 V, large short-circuit current density of 17.26 mA·cm-2, high fill factor of 0.846, and power conversion efficiency of 10%. With the Marcus model, in the BFBPD-PC61BM interface, the exciton-dissociation rate, kdis, was predicted to be 2.684×1013 s-1, which is as 3～5 orders of magnitude large as the decay (radiative and non-radiative) one (108～1010 s-1), indicating a high exciton-dissociation efficiency of 100% in the BFBPD-PC61BM interface. Furthermore, by the molecular dynamics simulation, the hole mobility of BFBPD thin-film was predicted to be as high as 1.265×10-2 cm2·V-1·s-1, which can be attributed to its dense packing in solid state.
分类： 核科学技术 >> 核聚变工程技术 提交时间： 2017-10-27
摘要： Purpose – The purpose of this paper is to develop a serial redundant manipulator system applied in nuclear fusion environment. It will allow remote inspection and maintenance of plasma facing components in the vacuum vessel of fusion device without breaking down the ultra-high vacuum condition during physical experiments. Design/methodology/approach – Firstly, considering the dynamic sealing of actuators to avoid polluting the vacuum condition inside fusion reactor, the mechanical design of robot system has been introduced. The redundant manipulator system has 11 degree of freedoms in total with an identical modular design. Besides, to improve the position accuracy, an error prediction model has been built based on the experimental study and back-propagation neural network (BPNN) algorithm. Findings – Currently, the implementation of the manipulator system has been successfully finished in both atmosphere and vacuum condition. The validation of BPNN model shown an acceptable prediction accuracy (94%~98%) compared with the real measurement. Originality/value – This is a special robot system which is practically used in a nuclear fusion device in China. Its design, mechanism and error prediction strategy have great reference values to the similar robots in vacuum and temperature applications.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-04-06
摘要：A new direct summation method, named as polyhedron method, is proposed to calculate Madelung energy. This method calculates sums of electrostatic interactions over sets of neutral polyhedron unit pairs rather than conventional ion pairs; this gives Madelu
分类： 生物学 >> 发育生物学 提交时间： 2017-03-31
摘要：[目的] 探索婴儿死亡率下降的历程。 [方法] 以日本和中国香港婴儿死亡率动态数列为参照系统，借鉴研究经济现象的方法，采用平均增长量、平均发展速度、平均增长速度描述分析婴儿死亡率的变化规律，分析下降历程。再通过婴儿死亡率随人均GDP变化轨迹进行验证，进一步分析191个WHO会员国2000-2013年下降规律与参照系统的符合率。按参照系统婴儿死亡率下降特征判别现阶段中国大陆婴儿死亡率所处的位置，预测未来下降历程。 [结果] 参照系统婴儿死亡率下降大致经历快速下降、缓慢下降、低水平持续状态三个阶段，婴儿死亡率随人均GDP变化轨迹与时间序列的规律相一致，191个国家下降规律与参照系统总体符合率为59.68%，快速下降、缓慢下降、低水平持续状态符合率分别为98.57%、21.62%、61.70%。中国大陆地区婴儿死亡率仍处于快速下降阶段，正向缓慢下降阶段过渡，“十四五”后期将进入低水平持续状态；城市婴儿死亡率处于缓慢下降阶段，“十二五”后期将向低水平持续状态过渡。 [结论] 婴儿死亡率下降存在着内在的变化规律，理想的下降历程值得发展中国家因地制宜地学习借鉴。在不同的发展阶段应制定、落实更有针对性的防控策略与措施。
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
摘要：Liver cancer stem cells (CSCs) harbour self-renewal and differentiation properties, accounting for chemotherapy resistance and recurrence. However, the molecular mechanisms to sustain liver CSCs remain largely unknown. In this study, based on analysis of several hepatocellular carcinoma (HCC) transcriptome datasets and our experimental data, we find that C8orf4 is weakly expressed in HCC tumours and liver CSCs. C8orf4 attenuates the self-renewal capacity of liver CSCs and tumour propagation. We show that NOTCH2 is activated in liver CSCs. C8orf4 is located in the cytoplasm of HCC tumour cells and associates with the NOTCH2 intracellular domain, which impedes the nuclear translocation of N2ICD. C8orf4 deletion causes the nuclear translocation of N2ICD that triggers the NOTCH2 signalling, which sustains the stemness of liver CSCs. Finally, NOTCH2 activation levels are consistent with clinical severity and prognosis of HCC patients. Altogether, C8orf4 negatively regulates the self-renewal of liver CSCs via suppression of NOTCH2 signalling.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
摘要：Identification and detection of dendritic spines in neuron images are of high interest in diagnosis and treatment of neurological and psychiatric disorders (e.g., Alzheimer's disease, Parkinson's diseases, and autism). In this paper, we have proposed a novel automatic approach using wavelet-based conditional symmetric analysis and regularized morphological shared-weight neural networks (RMSNN) for dendritic spine identification involving the following steps: backbone extraction, localization of dendritic spines, and classification. First, a new algorithm based on wavelet transform and conditional symmetric analysis has been developed to extract backbone and locate the dendrite boundary. Then, the RMSNN has been proposed to classify the spines into three predefined categories (mushroom, thin, and stubby). We have compared our proposed approach against the existing methods. The experimental result demonstrates that the proposed approach can accurately locate the dendrite and accurately classify the spines into three categories with the accuracy of 99.1% for "mushroom" spines, 97.6% for "stubby" spines, and 98.6% for "thin" spines.