针对间歇过程数据不足,单源域迁移存在模型偏移,跨域信息损失导致建模效果不佳、负迁移等问题,结合域适应学习和多源域学习方法的优势,提出一种基于多源域适应联合Y偏最小二乘(joint-Y partial least squares,JYPLS)迁移的间歇过程质量...针对间歇过程数据不足,单源域迁移存在模型偏移,跨域信息损失导致建模效果不佳、负迁移等问题,结合域适应学习和多源域学习方法的优势,提出一种基于多源域适应联合Y偏最小二乘(joint-Y partial least squares,JYPLS)迁移的间歇过程质量预测方法。该方法通过迁移学习使用相似旧过程的数据辅助新过程建模,提高建模效率和模型预测精度;采用多源域适应的方式,通过引入多个源域,有效避免了负迁移;基于域适应思想减少源域和目标域之间的边缘概率分布差异,使得源域知识在目标域更好地泛化。最后,通过青霉素发酵过程的仿真案例验证了所提方法的有效性。展开更多
目的:量化评估我国60岁及以上老年人恶性肿瘤的疾病负担,为我国恶性肿瘤的防控提供流行病学证据。方法:本研究收集了2008-2019年《中国肿瘤登记年报》中60岁及以上老年人恶性肿瘤患者的发病和死亡数据,计算伤残调整生命年(disability ad...目的:量化评估我国60岁及以上老年人恶性肿瘤的疾病负担,为我国恶性肿瘤的防控提供流行病学证据。方法:本研究收集了2008-2019年《中国肿瘤登记年报》中60岁及以上老年人恶性肿瘤患者的发病和死亡数据,计算伤残调整生命年(disability adjusted of life years,DALY)分析其疾病负担,使用Joinpoint模型对其进行时间趋势分析。结果:2005-2016年,我国老年人恶性肿瘤所致DALY共计25921678人年,DALY率波动范围为73.43‰~84.07‰,并以年均1.2%(95%CI:0.8%~1.5%)的速率下降。2005-2016年我国老年人寿命损失最多的恶性肿瘤是肺癌,年均寿命损失为28454人年,其次为胃癌、肝癌、食管癌和结直肠癌,以上五种肿瘤造成的寿命损失约占全部恶性肿瘤所致寿命损失的74.3%。85岁以上年龄组女性肺癌的DALY率随时间呈上升趋势(AAPC=1.8%,95%CI:0.7%~2.9%)。乳腺癌仅在女性60~64岁年龄组中排名前五,DALY率也呈上升趋势(AAPC=2.2%,95%CI:1.3%~3.0%)。随着年龄的增长,肝癌造成的疾病负担减轻,结直肠癌造成的疾病负担增加。结论:2005-2016年,我国老年人恶性肿瘤疾病负担有所下降,且存在年龄、性别、地区和恶性肿瘤类型差异。因此,相关部门应继续针对不同恶性肿瘤的分布特征,采取更加精准的防控措施,合理分配卫生资源,达到更加有效降低恶性肿瘤疾病负担的目标。展开更多
Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings. In order to remove these two types of defects, a 70 t 12Cr2Mo1 heavy ingot fa...Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings. In order to remove these two types of defects, a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis. To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions, simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software, respectively. Results show that the shrinkage defects do not appear in the middle-upper part of the ingot. The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results, which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights. However, large inclusions are found at the bottom of the ingot body. The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions. The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm.展开更多
In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio ...In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio method was used to determine embedding parameters to reconstruct the phase space.We used a multi-layer adaptive best-fitting parameter search algorithm to estimate the LS-SVM optimal parameters which were adopted to construct a LS-SVM prediction model for the mine water chaotic time series.The results show that the simulation performance of a single-step prediction based on this LS-SVM model is markedly superior to that based on a RBF model.The multi-step prediction results based on LS-SVM model can reflect the development of mine water discharge and can be used for short-term forecasting of mine water discharge.展开更多
油砂是固态或半固态的砂和其岩石中包含油的混和物,是常规油气资源的重要补充(Liu et al.,2019)。准噶尔盆地西北缘是我国油砂资源最为丰富的地区之。目前,准西油砂的勘探程度较低,以往研究局限于单个矿区或单个层位,或延续对深层常规...油砂是固态或半固态的砂和其岩石中包含油的混和物,是常规油气资源的重要补充(Liu et al.,2019)。准噶尔盆地西北缘是我国油砂资源最为丰富的地区之。目前,准西油砂的勘探程度较低,以往研究局限于单个矿区或单个层位,或延续对深层常规油气成因的认识(单玄龙等,2007;万初发等,2019;王启予,2020),尚未对整个西北缘各层系油砂的储层特征和成矿规律进行过系统对比研究(代振龙等,2022;马小平等,2022)。展开更多
文摘针对间歇过程数据不足,单源域迁移存在模型偏移,跨域信息损失导致建模效果不佳、负迁移等问题,结合域适应学习和多源域学习方法的优势,提出一种基于多源域适应联合Y偏最小二乘(joint-Y partial least squares,JYPLS)迁移的间歇过程质量预测方法。该方法通过迁移学习使用相似旧过程的数据辅助新过程建模,提高建模效率和模型预测精度;采用多源域适应的方式,通过引入多个源域,有效避免了负迁移;基于域适应思想减少源域和目标域之间的边缘概率分布差异,使得源域知识在目标域更好地泛化。最后,通过青霉素发酵过程的仿真案例验证了所提方法的有效性。
文摘目的:量化评估我国60岁及以上老年人恶性肿瘤的疾病负担,为我国恶性肿瘤的防控提供流行病学证据。方法:本研究收集了2008-2019年《中国肿瘤登记年报》中60岁及以上老年人恶性肿瘤患者的发病和死亡数据,计算伤残调整生命年(disability adjusted of life years,DALY)分析其疾病负担,使用Joinpoint模型对其进行时间趋势分析。结果:2005-2016年,我国老年人恶性肿瘤所致DALY共计25921678人年,DALY率波动范围为73.43‰~84.07‰,并以年均1.2%(95%CI:0.8%~1.5%)的速率下降。2005-2016年我国老年人寿命损失最多的恶性肿瘤是肺癌,年均寿命损失为28454人年,其次为胃癌、肝癌、食管癌和结直肠癌,以上五种肿瘤造成的寿命损失约占全部恶性肿瘤所致寿命损失的74.3%。85岁以上年龄组女性肺癌的DALY率随时间呈上升趋势(AAPC=1.8%,95%CI:0.7%~2.9%)。乳腺癌仅在女性60~64岁年龄组中排名前五,DALY率也呈上升趋势(AAPC=2.2%,95%CI:1.3%~3.0%)。随着年龄的增长,肝癌造成的疾病负担减轻,结直肠癌造成的疾病负担增加。结论:2005-2016年,我国老年人恶性肿瘤疾病负担有所下降,且存在年龄、性别、地区和恶性肿瘤类型差异。因此,相关部门应继续针对不同恶性肿瘤的分布特征,采取更加精准的防控措施,合理分配卫生资源,达到更加有效降低恶性肿瘤疾病负担的目标。
基金financially supported by the Program of National Technological Cooperation and Communication(Project 2010 DFR 70640)Chinese National S&T Major Project(2011ZX06004-016)
文摘Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings. In order to remove these two types of defects, a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis. To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions, simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software, respectively. Results show that the shrinkage defects do not appear in the middle-upper part of the ingot. The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results, which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights. However, large inclusions are found at the bottom of the ingot body. The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions. The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm.
基金supported by the Science and Research projects for Ph.D. candidates in the faculty of Xuzhou Normal University (No.08XLR12)Natural Science Foundation of Xuzhou Normal University (No.09XLA10)
文摘In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio method was used to determine embedding parameters to reconstruct the phase space.We used a multi-layer adaptive best-fitting parameter search algorithm to estimate the LS-SVM optimal parameters which were adopted to construct a LS-SVM prediction model for the mine water chaotic time series.The results show that the simulation performance of a single-step prediction based on this LS-SVM model is markedly superior to that based on a RBF model.The multi-step prediction results based on LS-SVM model can reflect the development of mine water discharge and can be used for short-term forecasting of mine water discharge.
文摘油砂是固态或半固态的砂和其岩石中包含油的混和物,是常规油气资源的重要补充(Liu et al.,2019)。准噶尔盆地西北缘是我国油砂资源最为丰富的地区之。目前,准西油砂的勘探程度较低,以往研究局限于单个矿区或单个层位,或延续对深层常规油气成因的认识(单玄龙等,2007;万初发等,2019;王启予,2020),尚未对整个西北缘各层系油砂的储层特征和成矿规律进行过系统对比研究(代振龙等,2022;马小平等,2022)。
