期刊文献+
共找到880篇文章
< 1 2 44 >
每页显示 20 50 100
一种基于自适应代理模型的并行贝叶斯优化方法
1
作者 吕志明 王霖青 +1 位作者 赵珺 刘颖 《控制与决策》 EI CSCD 北大核心 2019年第5期1025-1031,共7页
提出一种基于自适应代理模型的并行贝叶斯优化方法,用于求解计算成本高的复杂优化问题.该方法基于多点期望改进判据,通过批次采样实现并行优化.针对并行优化产生的大量历史数据会导致全局代理模型建模成本高的问题,提出一种改进的基于... 提出一种基于自适应代理模型的并行贝叶斯优化方法,用于求解计算成本高的复杂优化问题.该方法基于多点期望改进判据,通过批次采样实现并行优化.针对并行优化产生的大量历史数据会导致全局代理模型建模成本高的问题,提出一种改进的基于数据并行的高斯过程建模方法,在线构造局部代理模型.此外,针对多点期望改进判据计算成本高的问题,提出一种启发式的分层优化策略,通过序贯优化基于自适应代理模型的单点期望改进判据,近似计算多点期望改进判据.最后通过5个测试问题验证所提出方法的有效性. 展开更多
关键词 自适应 代理 并行 贝叶斯优化方法 期望改进
Multi-disciplinary design optimization with variable complexity modeling for a stratosphere airship
2
作者 Shi YIN Ming ZHU Haoquan LIANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第5期1244-1255,共12页
This paper proposes a hybrid architecture based on Multi-disciplinary Design Optimization(MDO) with the Variable Complexity Modeling(VCM) method, to solve the problem of general design optimization for a stratosphere ... This paper proposes a hybrid architecture based on Multi-disciplinary Design Optimization(MDO) with the Variable Complexity Modeling(VCM) method, to solve the problem of general design optimization for a stratosphere airship. Firstly, MDO based on the Concurrent SubSpace Optimization(CSSO) strategy is improved for handling the subsystem coupling problem in stratosphere airship design which contains aerodynamics, structure, and energy. Secondly, the VCM method based on the surrogate model is presented for reducing the computational complexity in high-fidelity modeling without loss of accuracy. Moreover, the global-to-local optimization strategy is added to the architecture to enhance the process. Finally, the result gives a prominent stratosphere airship general solution that validates the feasibility and efficiency of the optimization architecture. Besides, a sensitivity analysis is conducted to outline the critical impact upon stratosphere airship design. 展开更多
关键词 MULTI-DISCIPLINARY design optimization Sensitivity analysis STRATOSPHERE AIRSHIP Surrogate model VARIABLE COMPLEXITY MODELING
Detecting Nonlinear Dynamics Using BDS Test and Surrogate Data in Financial Time Series 预览
3
作者 Alex Neri Gutierrez Alexis Rodriguez Carranza Ana Gamarra Carrasco 《数学和系统科学:英文版》 2019年第2期46-53,共8页
Physicists experimentalists use many observations of a phenomenon, which are the unknown equations that describe it, in order to understand the dynamics and obtain information on their future behavior. In this article... Physicists experimentalists use many observations of a phenomenon, which are the unknown equations that describe it, in order to understand the dynamics and obtain information on their future behavior. In this article we study the possibility of reproducing the dynamics of the phenomenon using only a measurement scale. The Whitney immersion theorem ideas are presented and generalization of Sauer for fractal sets to rebuild the asymptotic behavior of the phenomena and to investigate evidence of nonlinear dynamics in the reproduced dynamics using the Brock, Dechert, Scheinkman test (BDS). The applications are made in the financial market which are only known stock prices. 展开更多
关键词 NONLINEAR DYNAMICS surrogate DATA BDS TEST and SERIAL TIMES
在线阅读 下载PDF
Multi-objective optimization of a flow straightener in a large capacity firefighting water cannon 预览
4
作者 Qing-jiang Xiang Lin Xue +1 位作者 Kwang-Yong Kim Zhe-fu Shi 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第1期137-144,共8页
In the present study,a multi-objective optimization of a flow straightener in a firefighting water cannon is performed by using the surrogate modeling and a hybrid multi-objective genetic algorithm to increase the jet... In the present study,a multi-objective optimization of a flow straightener in a firefighting water cannon is performed by using the surrogate modeling and a hybrid multi-objective genetic algorithm to increase the jet range of the water cannon.Based on analysis using the three-dimensional Reynolds-averaged Navier-Stokes equations,the optimization is carried with a surrogate model and the radial basis neural network.Three geometric design variables,i.e.,the lengt扎 the thickness of the blade,and the radius of the outer pipe of the flow straightener,are selected for the optimization.The pressure drop through the water can non and the area-averaged turbulent kinetic energy at the outlet of the water cannon,which are closely related to the jet range of the water cannon,are selected as the objective functions to be minimized.The design space is determined through a parametric study,and the Latin hypercube sampling method is used to select the design points in the design space.The Pareto-optimal solutions are obtained through the optimization.Five representative Pareto-optimal solutions are selected to study the trade-off between two objectives. 展开更多
关键词 FIREFIGHTING water cannon MULTI-OBJECTIVE optimization surrogate model TURBULENCE KINETIC energy hydraulic LOSS
在线阅读 下载PDF
Efficient multi-response adaptive sampling algorithm for construction of variable-fidelity aerodynamic tables
5
作者 Maxim TYAN Jae-Woo LEE 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第3期547-558,共12页
Adaptive sampling is an iterative process for the construction of a global approximation model. Most of engineering analysis tools computes multiple parameters in a single run. This research proposes a novel multi-res... Adaptive sampling is an iterative process for the construction of a global approximation model. Most of engineering analysis tools computes multiple parameters in a single run. This research proposes a novel multi-response adaptive sampling algorithm for simultaneous construction of multiple surrogate models in a time-efficient and accurate manner. The new algorithm uses the Jackknife cross-validation variance and a minimum distance metric to construct a sampling criterion function. A weighted sum of the function is used to consider the characteristics of multiple surrogate models. The proposed algorithm demonstrates good performance on total 22 numerical problems in comparison with three existing adaptive sampling algorithms. The numerical problems include several two-dimensional and six-dimensional functions which are combined into singleresponse and multi-response systems. Application of the proposed algorithm for construction of aerodynamic tables for 2 D airfoil is demonstrated. Scaling-based variable-fidelity modeling is implemented to enhance the accuracy of surrogate modeling. The algorithm succeeds in constructing a system of three highly nonlinear aerodynamic response surfaces within a reasonable amount of time while preserving high accuracy of approximation. 展开更多
关键词 Adaptive sampling Aerodynamic DATABASE Multi-response system Surrogate MODELING VARIABLE FIDELITY MODELING
Surrogate-Assisted Particle Swarm Optimization Algorithm With Pareto Active Learning for Expensive Multi-Objective Optimization 预览
6
作者 Zhiming Lv Linqing Wang +2 位作者 Zhongyang Han Jun Zhao Wei Wang 《自动化学报:英文版》 CSCD 2019年第3期838-849,共12页
For multi-objective optimization problems, particle swarm optimization (PSO) algorithm generally needs a large number of fitness evaluations to obtain the Pareto optimal solutions. However, it will become substantiall... For multi-objective optimization problems, particle swarm optimization (PSO) algorithm generally needs a large number of fitness evaluations to obtain the Pareto optimal solutions. However, it will become substantially time-consuming when handling computationally expensive fitness functions. In order to save the computational cost, a surrogate-assisted PSO with Pareto active learning is proposed. In real physical space (the objective functions are computationally expensive), PSO is used as an optimizer, and its optimization results are used to construct the surrogate models. In virtual space, objective functions are replaced by the cheaper surrogate models, PSO is viewed as a sampler to produce the candidate solutions. To enhance the quality of candidate solutions, a hybrid mutation sampling method based on the simulated evolution is proposed, which combines the advantage of fast convergence of PSO and implements mutation to increase diversity. Furthermore,ε-Pareto active learning (ε-PAL) method is employed to pre-select candidate solutions to guide PSO in the real physical space. However, little work has considered the method of determining parameter ε. Therefore, a greedy search method is presented to determine the value of ε where the number of active sampling is employed as the evaluation criteria of classification cost. Experimental studies involving application on a number of benchmark test problems and parameter determination for multi-input multi-output least squares support vector machines (MLSSVM) are given, in which the results demonstrate promising performance of the proposed algorithm compared with other representative multi-objective particle swarm optimization (MOPSO) algorithms. 展开更多
关键词 MULTIOBJECTIVE OPTIMIZATION PARETO active learning PARTICLE SWARM OPTIMIZATION (PSO) surrogate
在线阅读 下载PDF
Surrogate potency assays:Comparison of binding profiles complements dose response curves for unambiguous assessment of relative potencies 预览
7
作者 Robert Karlsson Veronica Fridh +1 位作者 Aa Frostell Asa Frostell 《药物分析学报:英文版》 CAS CSCD 2018年第2期138-146,共9页
Surface plasmon resonance(SPR)systems are widely used for detailed characterization of antibody activities including antigen and Fc-receptor binding.During the later stages of development,where the focus is to ensure ... Surface plasmon resonance(SPR)systems are widely used for detailed characterization of antibody activities including antigen and Fc-receptor binding.During the later stages of development,where the focus is to ensure that established critical quality attributes(CQAs)are maintained during cell culture,purification and formulation processes,analysis is simplified,and relative potencies are often determined.Here,simulation of binding data revealed that relative potency values,determined via parallel line analysis(PLA)and half maximal effective concentration(EC50)analysis accurately reflect changes in active concentration only if binding kinetics remain unchanged.Changes in the association rate constant shifted dose response curves,and therefore relative potencies,in the same way as changes in analyte concentration do.However,for interactions characterized by stable binding,changes in the dissociation rate constant did not result in any shift,suggesting that this type of change may go unnoticed in the dose response curve.Thus,EC50 and PLA analyses of dose response curves obtained with an anti-TNF-αantibody were complemented with the Biacore functionality for sensorgram comparison analysis,whereby changes in antigen and Fc-receptor binding profiles could be detected.Next,analysis of temperature stressed TNF-αantibody revealed that calibration free concentration analysis(CFCA)data correlated perfectly with relative potency values.Together,these results demonstrate that combinations of SPR based dose response curves,sensorgram comparison and CFCA can be used to strengthen the confidence in relative potency assessments,and suggest that SPR can potentially be used as a surrogate potency assay in the quality control of biotherapeutic medicines. 展开更多
关键词 Surface PLASMON resonance EC50 Sensorgram COMPARISON Calibration free concentration analysis Surrogate POTENCY assay TNF-α
在线阅读 下载PDF
Proton nuclear magnetic resonance-based metabonomic models for non-invasive diagnosis of liver fibrosis in chronic hepatitis C:Optimizing the classification of intermediate fibrosis 预览
8
作者 Andrea Dória Batista Carlos Jonnatan Pimentel Barros +7 位作者 Tássia Brena Barroso Carneiro Costa Michele Maria Goncalves de Godoy Ronaldo Dionísio Silva Joelma Carvalho Santos Mariana Montenegro de Melo Lira Norma ThoméJucá Edmundo Pessoa de Almeida Lopes Ricardo Oliveira Silva 《世界肝病学杂志:英文版(电子版)》 2018年第1期105-115,共11页
AIM To develop metabonomic models(MMs),using 1H nuclear magnetic resonance(NMR)spectra of serum,to predict significant liver fibrosis(SF:Metavir≥F2),advanced liver fibrosis(AF:METAVIR≥F3)and cirrhosis(C:METAVIR=F4 o... AIM To develop metabonomic models(MMs),using 1H nuclear magnetic resonance(NMR)spectra of serum,to predict significant liver fibrosis(SF:Metavir≥F2),advanced liver fibrosis(AF:METAVIR≥F3)and cirrhosis(C:METAVIR=F4 or clinical cirrhosis)in chronic hepatitis C(CHC)patients.Additionally,to compare the accuracy of the MMs with the aspartate aminotransferase to platelet ratio index(APRI)and fibrosis index based on four factors(FIB-4).METHODS Sixty-nine patients who had undergone biopsy in the previous 12 mo or had clinical cirrhosis were included.The presence of any other liver disease was a criterion for exclusion.The MMs,constructed using partial least squares discriminant analysis and linear discriminant analysis formalisms,were tested by cross-validation,considering SF,AF and C.RESULTS Results showed that forty-two patients(61%)presented SF,28(40%)AF and 18(26%)C.The MMs showed sensitivity and specificity of 97.6%and 92.6%to predict SF;96.4%and 95.1%to predict AF;and 100%and 98.0%to predict C.Besides that,the MMs correctly classified all 27(39.7%)and 25(38.8%)patients with intermediate values of APRI and FIB-4,respectively.CONCLUSION The metabonomic strategy performed excellently in predicting significant and advanced liver fibrosis in CHC patients,including those in the gray zone of APRI and FIB-4,which may contribute to reducing the need for these patients to undergo liver biopsy. 展开更多
关键词 Metabolomics Nuclear magnetic resonance spectroscopy Chronic hepatitis C Liver FIBROSIS Surrogate MARKERS
在线阅读 免费下载
Safety Analysis of the Eco-Approach and Departure Application at a Signalized Corridor
9
作者 Weixia Li Guoyuan Wu +1 位作者 Yi Zhang Matthew J. Barth 《清华大学学报:自然科学英文版》 EI CAS CSCD 2018年第2期157-171,共15页
Various intelligent transportation systems and strategies for reducing vehicle fuel consumption andemissions have been developed. Energy and emissions could be reduced with the compromise of travel timein some environ... Various intelligent transportation systems and strategies for reducing vehicle fuel consumption andemissions have been developed. Energy and emissions could be reduced with the compromise of travel timein some environment-focused Connected Vehicle (CV) applications, which highlighted performance measures interms of mobility and sustainability. Nevertheless, few studies have focused on safety assessment of such CVapplications. In this study, a CV-based eco-driving application, namely, Eco-Approach and Departure (EAD), isselected as an example. A microscopic safety analysis tool, Surrogate Safety Assessment Model (SSAM), isutilized to assess the safety influence of EAD application in multiple scenarios. Further analysis is performed fromtwo perspectives: (1) application users, i.e., EAD-equipped vehicles versus unequipped vehicles; and (2) trafficoperators, i.e., overall traffic performance with and without the introduction of EAD. For each perspective, conflictstatistics (e.g., frequency, time-to-collision distribution), overall and by type, are analyzed. Results indicate EADis beneficial in improving the safety performance of equipped vehicles. The influence of EAD on overall traffic isscenario dependent, and a high penetration rate shows positive effects on network-wide safety benefits for mostscenarios. 展开更多
关键词 Eco-Approach and DEPARTURE (EAD) Surrogate SAFETY Assessment Model (SSAM) SAFETY analysis conflict type Time-To-Collision (TTC)
因果推断的统计方法
10
作者 苗旺 刘春辰 耿直 《中国科学:数学》 CSCD 北大核心 2018年第12期1753-1778,共26页
探索事物之间的因果关系和因果作用是很多科学研究的重要目的.因果推断的统计方法是利用试验性研究和观察性研究得到的数据,评价变量之间的因果作用和挖掘多个变量之间的因果关系.本文将介绍因果作用和因果关系的形式化定义,以及因果推... 探索事物之间的因果关系和因果作用是很多科学研究的重要目的.因果推断的统计方法是利用试验性研究和观察性研究得到的数据,评价变量之间的因果作用和挖掘多个变量之间的因果关系.本文将介绍因果作用和因果关系的形式化定义,以及因果推断的两个主要统计模型:潜在结果模型和因果网络模型·本文将探讨因果作用的可识别性和因果网络的结构学习,综述有关因果推断的若干研究问题和动态. 展开更多
关键词 因果作用 因果网络 混杂因素 潜在结果模型 替代指标 因果推断 有向无环图
Multikinase inhibitor-associated hand-foot skin reaction as a predictor of outcomes in patients with hepatocellular carcinoma treated with sorafenib 预览
11
作者 Masanori Ochi Toshiro Kamoshida +4 位作者 Atsushi Ohkawara Haruka Ohkawara Nobushige Kakinoki Shinji Hirai Akinori Yanaka 《世界胃肠病学杂志:英文版》 SCIE CAS 2018年第28期3155-3162,共8页
AIM To investigate the relationship between the onsets of multikinase inhibitor(MKI)-associated hand-foot skin reaction(HFSR)and prognosis under intervention by pharmacists after the introduction of sorafenib.METHODS ... AIM To investigate the relationship between the onsets of multikinase inhibitor(MKI)-associated hand-foot skin reaction(HFSR)and prognosis under intervention by pharmacists after the introduction of sorafenib.METHODS We conducted a retrospective study involving 40 patients treated with sorafenib.Intervention by pharmacists began at the time of treatment introduction and continued until the appearance of symptomatic exacerbation or non-permissible adverse reactions.We examined the relationship between MKI-associated HFSR and overall survival(OS)after the initiation of treatment.RESULTS The median OS was 10.9 mo in the MKI-associated HFSR group and 3.4 mo in the no HFSR group,showing a significant difference in multivariate analysis.A multivariate analysis of the time to treatment failure indicated that the intervention by pharmacists and MKI-associated HFSR were significant factors.The median cumulative dose and the mean medication possession ratio were significantly higher in the intervention group than in the non-intervention group.A borderline significant difference was observed in terms of OS in this group.CONCLUSION Intervention by pharmacists increased drug adherence.Under increased adherence,MKI-associated HFSR was an advantageous surrogate marker.Intervention by healthcare providers needs to be performed for adequate sorafenib treatment. 展开更多
关键词 Hepatocellular carcinoma Surrogate marker Multikinase inhibitor-associated hand-foot skin reaction SORAFENIB INTERVENTION by PHARMACISTS
在线阅读 免费下载
碳氢燃料燃烧化学反应动力学模型研究进展 预览
12
作者 耿瑞光 金大桥 +1 位作者 苗志滨 李伟 《黑龙江工程学院学报》 CAS 2018年第1期41-45,共5页
碳氢燃料是交通运输领域动力装置最主要的能量来源,是组分复杂的碳氢化合物的混合物。为了研究碳氢燃料的点火、燃烧以及排放物等特性,需要采用相对简单的替代模型。在对常用石油基碳氢燃料进行阐述的基础上,针对不同的研究目的,对国内... 碳氢燃料是交通运输领域动力装置最主要的能量来源,是组分复杂的碳氢化合物的混合物。为了研究碳氢燃料的点火、燃烧以及排放物等特性,需要采用相对简单的替代模型。在对常用石油基碳氢燃料进行阐述的基础上,针对不同的研究目的,对国内外涉及车用燃料和航空用燃料的柴油和煤油的替代燃料动力学模型的研究进展进行全面的介绍。 展开更多
关键词 燃料 碳氢化合物 燃烧 替代物 建模
在线阅读 下载PDF
航空替代燃料低温氧化实验与模型研究
13
作者 王丙寅 刘岳曦 +2 位作者 潘冠福 翁俊桀 田振玉 《工程热物理学报》 EI CAS CSCD 北大核心 2017年第3期648-656,共9页
在射流搅拌反应器中开展了常压航空煤油替代燃料的低温(500-1100 K)氧化实验研究。利用气相色谱和气质联用仪测得了34个物种的摩尔分数曲线。通过研究芳烃和正癸烷间的耦合作用阐述了替代燃料低温区负温度系数效应对燃料燃烧特性的影... 在射流搅拌反应器中开展了常压航空煤油替代燃料的低温(500-1100 K)氧化实验研究。利用气相色谱和气质联用仪测得了34个物种的摩尔分数曲线。通过研究芳烃和正癸烷间的耦合作用阐述了替代燃料低温区负温度系数效应对燃料燃烧特性的影响,揭示了实际航空燃料的低温自动点火机理。建立包括975物种和5920反应的亚琛替代燃料的动力学模型,并利用该模型准确地预测实际燃料燃烧的点火延迟等。实验和模拟得到的结果有助于理解燃气轮机低温点火过程。 展开更多
关键词 替代燃料 射流搅拌反应器 低温氧化 负温度系数 污染物形成路径
Sheet Metal Forming Optimization by Using Surrogate Modeling Techniques
14
作者 WANG Hu YE Fan +1 位作者 CHEN Lei LI Enying 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2017年第1期22-36,共15页
Surrogate assisted optimization has been widely applied in sheet metal forming design due to its efficiency. Therefore, to improve the efficiency of design and reduce the product development cycle, it is important for... Surrogate assisted optimization has been widely applied in sheet metal forming design due to its efficiency. Therefore, to improve the efficiency of design and reduce the product development cycle, it is important for scholars and engineers to have some insight into the performance of each surrogate assisted optimization method and make them more flexible practically. For this purpose, the state-of-the-art surrogate assisted optimizations are investigated. Furthermore, in view of the bottleneck and development of the surrogate assisted optimization and sheet metal forming design, some important issues on the surrogate assisted optimization in support of the sheet metal forming design are analyzed and discussed, involving the description of the sheet metal forming design, off-line and online sampling strategies, space mapping algorithm, high dimensional problems, robust design, some challenges and potential feasible methods. Generally, this paper provides insightful observations into the performance and potential development of these methods in sheet metal forming design. 展开更多
关键词 板料成形 优化 建模技术 成形设计 产品开发周期 金属板材成形 工作效率 设计效率
Recurrence-free survival as a putative surrogate for overall survival in phaseⅢtrials of curative-intent treatment of colorectal liver metastases:Systematic review 预览
15
作者 Raphael LC Araujo Paulo Herman Rachel P Riechelmann 《世界临床肿瘤学杂志》 2017年第3期266-272,共7页
AIM To verify whether recurrence-free survival(RFS)surrogates overall survival(OS)in phaseⅢtrials for resectable colorectal liver metastases(CRLM).METHODS MEDLINE,EMBASE,and Scopus databases were consulted.Eligible s... AIM To verify whether recurrence-free survival(RFS)surrogates overall survival(OS)in phaseⅢtrials for resectable colorectal liver metastases(CRLM).METHODS MEDLINE,EMBASE,and Scopus databases were consulted.Eligible studies were phaseⅢtrials testing any type of systemic therapy(neoadjuvant,adjuvant or perioperative)added to surgery in patients with resectable CRLM.A linear regression model based on hazard ratios(HR)of OS and RFS was performed.RESULTS Of 3059 studies,5 phaseⅢtrials(1162 patients)were included for analyses.A linear regression weighted by each trial was used to estimate the association between each HR and RFS.The originated formula was:OS HR=(0.93×RFS HR)+0.14;with RFS 95%CI(0.48-1.38),with P=0.007.CONCLUSION This association suggests that RFS could work as a putative surrogate endpoint of OS in this population,avoiding bigger,longer and more resource-consuming trials.The OS could be assumed based on RFS and our model could be useful to better estimate sample size calculations of phaseⅢtrials of CRLM aiming for OS. 展开更多
关键词 Colorectal liver METASTASES Surgery Chemotherapy Clinical TRIAL Long-term OUTCOMES Surrogate ENDPOINTS
在线阅读 免费下载
科技进步拓展意思自治之适用空间——论代孕中亲子关系的认定的规制模式选择 预览 被引量:2
16
作者 关剑夫 《科技与法律》 2016年第1期52-65,共14页
人工辅助生殖技术的进步使得人类获得了前所未有的操纵生殖过程的自由。这一自由正在我国被大量利用,以帮助众多家庭克服不孕不育的困境。然而私法规制的缺位导致当事人,尤其是代孕生育子女的权利难以得到保障。在规制代孕中的亲子关系... 人工辅助生殖技术的进步使得人类获得了前所未有的操纵生殖过程的自由。这一自由正在我国被大量利用,以帮助众多家庭克服不孕不育的困境。然而私法规制的缺位导致当事人,尤其是代孕生育子女的权利难以得到保障。在规制代孕中的亲子关系时,"事实行为"模式呆板僵化,无法满足现实需求;"法律行为"模式,立足于科技进步带来的伦理物可支配性,采取尊重当事人的自由意志的态度,将科技催生的新生事物纳入社会家庭伦常的轨道,既具有可行性,又具有必要性。 展开更多
关键词 代孕 亲子关系认定 意思自治
在线阅读 下载PDF
代孕的法律规制研究 预览 被引量:1
17
作者 徐艳 任正东 蒋涛 《怀化学院学报》 2016年第12期74-77,共4页
代孕的出现给不孕症家庭带来了新的希望,但同时传统伦理观念的束缚、法律规范的缺位又使他面临一系列的挑战,完善代孕的法律规制,使其趋利避害、有效应用,已经迫在眉睫。通过对代孕所面临的伦理和法律问题的分析,论述其有限适度适用的... 代孕的出现给不孕症家庭带来了新的希望,但同时传统伦理观念的束缚、法律规范的缺位又使他面临一系列的挑战,完善代孕的法律规制,使其趋利避害、有效应用,已经迫在眉睫。通过对代孕所面临的伦理和法律问题的分析,论述其有限适度适用的合理性,并从代孕的适用主体、代孕双方的权利义务、代孕技术的适用监管等方面提出完善建议,有利于实现其合法规范有序运行,真正发挥其价值所在。 展开更多
关键词 代孕 完全代孕 法律规制
在线阅读 下载PDF
煤基喷气燃料代用组分神经网络混合构建方法
18
作者 刘振涛 许全宏 +2 位作者 张弛 霍伟业 林宇震 《航空动力学报》 EI CAS CSCD 北大核心 2016年第11期2652-2658,共7页
为了建立航空燃料的喷雾模型,用于高保真液雾燃烧数值模拟,提出了基于人工神经网络混合模型的煤基喷气燃料代用组分构建方法.基于这一构建方法,重点针对煤基喷气燃料的雾化特性,利用多组分混合燃料的理化性质数据库对神经网络进行训练,... 为了建立航空燃料的喷雾模型,用于高保真液雾燃烧数值模拟,提出了基于人工神经网络混合模型的煤基喷气燃料代用组分构建方法.基于这一构建方法,重点针对煤基喷气燃料的雾化特性,利用多组分混合燃料的理化性质数据库对神经网络进行训练,获得了混合燃料理化性质隐式预测模型,结合随机投点优化方法,构建出能够很好地模拟煤基喷气燃料目标理化性质的代用组分.结果表明:该代用组分包含了5种碳氢化合物成分,摩尔分数为11.46%正癸烷、23.29%正十二烷、49.87%正十四烷、6.66%异辛烷和8.72%甲基环己烷.通过雾化特性实验,验证了代用组分对真实燃料雾化性能的模拟效果.该代用组分构建方法可以较好地解决混合燃料模拟过程中的非线性问题,通过改变目标理化性质可构建出相应代用组分. 展开更多
关键词 煤基喷气燃料 代用组分 神经网络 优化 雾化
Prioritization of COPD protein biomarkers,based on a systematic study of the literature 预览
19
作者 Sara Ongay Frank Klont +2 位作者 Peter Horvatovich Rainer Bischoff Nick HTten Hacken 《精准医疗前沿》 2016年第1期12-24,共13页
Chronic Obstructive Pulmonary Disease(COPD)is a chronic lung disease mostly due to smoking and until now diagnosed by spirometry(post bronchodilator FEV1/FVC<70%).However,in spite of the usefulness of FEV1 as diagn... Chronic Obstructive Pulmonary Disease(COPD)is a chronic lung disease mostly due to smoking and until now diagnosed by spirometry(post bronchodilator FEV1/FVC<70%).However,in spite of the usefulness of FEV1 as diagnostic and prognostic tool,it has proven to be a weak indicator of future exacerbations,unable to predict lung function decline within COPD patients,as well as unable to identify the smokers“susceptible”to developing COPD at an early stage.Thus,there is an urgent need for biomarkers that address these questions and support clinical decision making in the diagnosis and treatment of(early)COPD.In this respect,considerable efforts have been devoted to identifying protein biomarkers that enable a better understanding of this complex disease and leading to better diagnostic and prognostic tools.However,in spite of the wide range of candidates that have been suggested as potentially useful COPD biomarkers,most remained at the level of the initial discovery,and only fibrinogen has been approved by the Food and Drug Administration(FDA)as predictor for all-cause mortality and COPD exacerbations.There is thus a need for future investigations of these biomarkers in large-scale and well characterized studies in order to prove their usefulness as surrogate endpoints.Based on this,the aim of the present review is to advance COPD biomarker development by providing a comprehensive overview of protein biomarker candidates which have been evaluated in clinical studies and prioritize them according to their potential of becoming valid,clinically useful COPD biomarkers. 展开更多
关键词 COPD BIOMARKER surrogate marker REVIEW
在线阅读 下载PDF
基于可变环境标准约束的地下水修复优化模型 预览
20
作者 徐宗达 何理 +1 位作者 卢宏玮 樊星 《水资源保护》 CAS CSCD 2016年第1期176-183,194共9页
提出了一个集成的模拟-优化方法用于设计不确定条件下受石油污染的地下水最优修复方法。该方法有以下4个优点:1通过建立的代理回归模型给修复策略(井的抽注速率)和修复性能(污染物浓度)之间提供了直接且响应迅速的桥梁;2减轻优化... 提出了一个集成的模拟-优化方法用于设计不确定条件下受石油污染的地下水最优修复方法。该方法有以下4个优点:1通过建立的代理回归模型给修复策略(井的抽注速率)和修复性能(污染物浓度)之间提供了直接且响应迅速的桥梁;2减轻优化过程中产生的计算工作量;3提供一个能够揭示满足环境质量标准程度大小的满意度水平;4防止过于乐观或悲观的优化策略的制定。将该方法应用于位于安徽省某发电厂受石油污染的地下水含水层区域,用来识别最佳的修复策略。结果表明:在较宽松的、对修复效果影响不是很大的环境标准或者较长的修复周期条件下,大多数抽注修复井的抽注速率将会减小,伸缩指数的增加对修复优化结果并没有产生严重影响。 展开更多
关键词 地下水修复 模拟 优化 代理模型 伸缩指数
在线阅读 下载PDF
上一页 1 2 44 下一页 到第
使用帮助 返回顶部 意见反馈