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A Pooling Method Developed for Use in Convolutional Neural Networks
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作者 Ìsmail Akgül 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期751-770,共20页
In convolutional neural networks,pooling methods are used to reduce both the size of the data and the number of parameters after the convolution of the models.These methods reduce the computational amount of convoluti... In convolutional neural networks,pooling methods are used to reduce both the size of the data and the number of parameters after the convolution of the models.These methods reduce the computational amount of convolutional neural networks,making the neural network more efficient.Maximum pooling,average pooling,and minimum pooling methods are generally used in convolutional neural networks.However,these pooling methods are not suitable for all datasets used in neural network applications.In this study,a new pooling approach to the literature is proposed to increase the efficiency and success rates of convolutional neural networks.This method,which we call MAM(Maximum Average Minimum)pooling,is more interactive than other traditional maximum pooling,average pooling,and minimum pooling methods and reduces data loss by calculating the more appropriate pixel value.The proposed MAM pooling method increases the performance of the neural network by calculating the optimal value during the training of convolutional neural networks.To determine the success accuracy of the proposed MAM pooling method and compare it with other traditional pooling methods,training was carried out on the LeNet-5 model using CIFAR-10,CIFAR-100,and MNIST datasets.According to the results obtained,the proposed MAM pooling method performed better than the maximum pooling,average pooling,and minimum pooling methods in all pool sizes on three different datasets. 展开更多
关键词 pooling convolutional neural networks deep learning
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Effects of pooling,specialization,and discretionary task completion on queueing performance
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作者 JIANG Houyuan 《运筹学学报(中英文)》 CSCD 北大核心 2024年第3期81-96,共16页
Pooling,unpooling/specialization,and discretionary task completion are typical operational strategies in queueing systems that arise in healthcare,call centers,and online sales.These strategies may have advantages and... Pooling,unpooling/specialization,and discretionary task completion are typical operational strategies in queueing systems that arise in healthcare,call centers,and online sales.These strategies may have advantages and disadvantages in different operational environments.This paper uses the M/M/1 and M/M/2 queues to study the impact of pooling,specialization,and discretionary task completion on the average queue length.Closed-form solutions for the average M/M/2 queue length are derived.Computational examples illustrate how the average queue length changes with the strength of pooling,specialization,and discretionary task completion.Finally,several conjectures are made in the paper. 展开更多
关键词 queuing systems pooling SPECIALIZATION discretionary task completion average queue length
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A multi-scale second-order autoregressive recursive filter approach for the sea ice concentration analysis
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作者 Lu Yang Xuefeng Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第3期115-126,共12页
To effectively extract multi-scale information from observation data and improve computational efficiency,a multi-scale second-order autoregressive recursive filter(MSRF)method is designed.The second-order autoregress... To effectively extract multi-scale information from observation data and improve computational efficiency,a multi-scale second-order autoregressive recursive filter(MSRF)method is designed.The second-order autoregressive filter used in this study has been attempted to replace the traditional first-order recursive filter used in spatial multi-scale recursive filter(SMRF)method.The experimental results indicate that the MSRF scheme successfully extracts various scale information resolved by observations.Moreover,compared with the SMRF scheme,the MSRF scheme improves computational accuracy and efficiency to some extent.The MSRF scheme can not only propagate to a longer distance without the attenuation of innovation,but also reduce the mean absolute deviation between the reconstructed sea ice concentration results and observations reduced by about 3.2%compared to the SMRF scheme.On the other hand,compared with traditional first-order recursive filters using in the SMRF scheme that multiple filters are executed,the MSRF scheme only needs to perform two filter processes in one iteration,greatly improving filtering efficiency.In the two-dimensional experiment of sea ice concentration,the calculation time of the MSRF scheme is only 1/7 of that of SMRF scheme.This means that the MSRF scheme can achieve better performance with less computational cost,which is of great significance for further application in real-time ocean or sea ice data assimilation systems in the future. 展开更多
关键词 second-order auto-regressive filter multi-scale recursive filter sea ice concentration three-dimensional variational data assimilation
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Bayesian partial pooling to reduce uncertainty in overcoring rock stress estimation
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作者 Yu Feng Ke Gao Suzanne Lacasse 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1192-1201,共10页
The state of in situ stress is a crucial parameter in subsurface engineering,especially for critical projects like nuclear waste repository.As one of the two ISRM suggested methods,the overcoring(OC)method is widely u... The state of in situ stress is a crucial parameter in subsurface engineering,especially for critical projects like nuclear waste repository.As one of the two ISRM suggested methods,the overcoring(OC)method is widely used to estimate the full stress tensors in rocks by independent regression analysis of the data from each OC test.However,such customary independent analysis of individual OC tests,known as no pooling,is liable to yield unreliable test-specific stress estimates due to various uncertainty sources involved in the OC method.To address this problem,a practical and no-cost solution is considered by incorporating into OC data analysis additional information implied within adjacent OC tests,which are usually available in OC measurement campaigns.Hence,this paper presents a Bayesian partial pooling(hierarchical)model for combined analysis of adjacent OC tests.We performed five case studies using OC test data made at a nuclear waste repository research site of Sweden.The results demonstrate that partial pooling of adjacent OC tests indeed allows borrowing of information across adjacent tests,and yields improved stress tensor estimates with reduced uncertainties simultaneously for all individual tests than they are independently analysed as no pooling,particularly for those unreliable no pooling stress estimates.A further model comparison shows that the partial pooling model also gives better predictive performance,and thus confirms that the information borrowed across adjacent OC tests is relevant and effective. 展开更多
关键词 Overcoring stress measurement Uncertainty reduction Partial pooling Bayesian hierarchical model Nuclear waste repository
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U-Net Based Dual-Pooling Segmentation of Bone Metastases in Thoracic SPECT Bone Scintigrams
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作者 Yang He Qiang Lin +1 位作者 Yongchun Cao Zhengxing Man 《Journal of Computer and Communications》 2024年第4期60-71,共12页
In order to enhance the performance of the CNN-based segmentation models for bone metastases, this study proposes a segmentation method that integrates dual-pooling, DAC, and RMP modules. The network consists of disti... In order to enhance the performance of the CNN-based segmentation models for bone metastases, this study proposes a segmentation method that integrates dual-pooling, DAC, and RMP modules. The network consists of distinct feature encoding and decoding stages, with dual-pooling modules employed in encoding stages to maintain the background information needed for bone scintigrams diagnosis. Both the DAC and RMP modules are utilized in the bottleneck layer to address the multi-scale problem of metastatic lesions. Experimental evaluations on 306 clinical SPECT data have demonstrated that the proposed method showcases a substantial improvement in both DSC and Recall scores by 3.28% and 6.55% compared the baseline. Exhaustive case studies illustrate the superiority of the methodology. 展开更多
关键词 Tumor Bone Metastasis Bone Scintigram Lesion Segmentation CNN Dual pooling
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The Convergence Rate of Fréchet Distribution under the Second-Order Regular Variation Condition
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作者 Xilai Dai 《Journal of Applied Mathematics and Physics》 2024年第5期1597-1605,共9页
In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order ... In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order regular variation condition. 展开更多
关键词 Convergence Rate second-order Regular Variation Condition Fréchet Distribution Extreme Value Index
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Closed-form steady-state solutions for forced vibration of second-order axially moving systems
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作者 Jingming FAN Bo CHEN Yinghui LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第10期1701-1720,共20页
Second-order axially moving systems are common models in the field of dynamics, such as axially moving strings, cables, and belts. In the traditional research work, it is difficult to obtain closed-form solutions for ... Second-order axially moving systems are common models in the field of dynamics, such as axially moving strings, cables, and belts. In the traditional research work, it is difficult to obtain closed-form solutions for the forced vibration when the damping effect and the coupling effect of multiple second-order models are considered.In this paper, Green's function method based on the Laplace transform is used to obtain closed-form solutions for the forced vibration of second-order axially moving systems. By taking the axially moving damping string system and multi-string system connected by springs as examples, the detailed solution methods and the analytical Green's functions of these second-order systems are given. The mode functions and frequency equations are also obtained by the obtained Green's functions. The reliability and convenience of the results are verified by several examples. This paper provides a systematic analytical method for the dynamic analysis of second-order axially moving systems, and the obtained Green's functions are applicable to different second-order systems rather than just string systems. In addition, the work of this paper also has positive significance for the study on the forced vibration of high-order systems. 展开更多
关键词 Green's function axially moving system closed-form solution second-order model forced vibration Laplace transform
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Three-dimensional mixed convection stagnation-point fow past a vertical surface with second-order slip velocity
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作者 A.V.ROSCA N.C.ROSCA I.POP 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第4期641-652,共12页
This study is concerned with the three-dimensional(3D)stagnation-point for the mixed convection flow past a vertical surface considering the first-order and secondorder velocity slips.To the authors’knowledge,this is... This study is concerned with the three-dimensional(3D)stagnation-point for the mixed convection flow past a vertical surface considering the first-order and secondorder velocity slips.To the authors’knowledge,this is the first study presenting this very interesting analysis.Nonlinear partial differential equations for the flow problem are transformed into nonlinear ordinary differential equations(ODEs)by using appropriate similarity transformation.These ODEs with the corresponding boundary conditions are numerically solved by utilizing the bvp4c solver in MATLAB programming language.The effects of the governing parameters on the non-dimensional velocity profiles,temperature profiles,skin friction coefficients,and the local Nusselt number are presented in detail through a series of graphs and tables.Interestingly,it is reported that the reduced skin friction coefficient decreases for the assisting flow situation and increases for the opposing flow situation.The numerical computations of the present work are compared with those from other research available in specific situations,and an excellent consensus is observed.Another exciting feature for this work is the existence of dual solutions.An important remark is that the dual solutions exist for both assisting and opposing flows.A linear stability analysis is performed showing that one solution is stable and the other solution is not stable.We notice that the mixed convection and velocity slip parameters have strong effects on the flow characteristics.These effects are depicted in graphs and discussed in this paper.The obtained results show that the first-order and second-order slip parameters have a considerable effect on the flow,as well as on the heat transfer characteristics. 展开更多
关键词 three-dimensional(3D)mixed convection flow stagnation point flow first-order slip velocity second-order slip velocity numerical solution stability analysis
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Six New Sets of the Non-Elementary Jef-Family-Functions that Are Giving Solutions to Some Second-Order Nonlinear Autonomous ODEs
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作者 Magne Stensland 《Journal of Applied Mathematics and Physics》 2023年第4期1077-1097,共21页
In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are usi... In this paper, we define some new sets of non-elementary functions in a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We are using Abel’s methods, described by Armitage and Eberlein. The key is to start with a non-elementary integral function, differentiating and inverting, and then define a set of three functions that belong together. Differentiating these functions twice gives second-order nonlinear ODEs that have the defined set of functions as solutions. We will study some of the second-order nonlinear ODEs, especially those that exhibit limit cycles. Using the methods described in this paper, it is possible to define many other sets of non-elementary functions that are giving solutions to some second-order nonlinear autonomous ODEs. 展开更多
关键词 Non-Elementary Functions second-order Nonlinear Autonomous ODE Limit Cycle
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Second-Order MaxEnt Predictive Modelling Methodology. I: Deterministically Incorporated Computational Model (2nd-BERRU-PMD)
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作者 Dan Gabriel Cacuci 《American Journal of Computational Mathematics》 2023年第2期236-266,共31页
This work presents a comprehensive second-order predictive modeling (PM) methodology designated by the acronym 2<sup>nd</sup>-BERRU-PMD. The attribute “2<sup>nd</sup>” indicates that this met... This work presents a comprehensive second-order predictive modeling (PM) methodology designated by the acronym 2<sup>nd</sup>-BERRU-PMD. The attribute “2<sup>nd</sup>” indicates that this methodology incorporates second-order uncertainties (means and covariances) and second-order sensitivities of computed model responses to model parameters. The acronym BERRU stands for “Best- Estimate Results with Reduced Uncertainties” and the last letter (“D”) in the acronym indicates “deterministic,” referring to the deterministic inclusion of the computational model responses. The 2<sup>nd</sup>-BERRU-PMD methodology is fundamentally based on the maximum entropy (MaxEnt) principle. This principle is in contradistinction to the fundamental principle that underlies the extant data assimilation and/or adjustment procedures which minimize in a least-square sense a subjective user-defined functional which is meant to represent the discrepancies between measured and computed model responses. It is shown that the 2<sup>nd</sup>-BERRU-PMD methodology generalizes and extends current data assimilation and/or data adjustment procedures while overcoming the fundamental limitations of these procedures. In the accompanying work (Part II), the alternative framework for developing the “second- order MaxEnt predictive modelling methodology” is presented by incorporating probabilistically (as opposed to “deterministically”) the computed model responses. 展开更多
关键词 second-order Predictive Modeling Data Assimilation Data Adjustment Uncertainty Quantification Reduced Predicted Uncertainties
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Second-Order MaxEnt Predictive Modelling Methodology. II: Probabilistically Incorporated Computational Model (2nd-BERRU-PMP)
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作者 Dan Gabriel Cacuci 《American Journal of Computational Mathematics》 2023年第2期267-294,共28页
This work presents a comprehensive second-order predictive modeling (PM) methodology based on the maximum entropy (MaxEnt) principle for obtaining best-estimate mean values and correlations for model responses and par... This work presents a comprehensive second-order predictive modeling (PM) methodology based on the maximum entropy (MaxEnt) principle for obtaining best-estimate mean values and correlations for model responses and parameters. This methodology is designated by the acronym 2<sup>nd</sup>-BERRU-PMP, where the attribute “2<sup>nd</sup>” indicates that this methodology incorporates second- order uncertainties (means and covariances) and second (and higher) order sensitivities of computed model responses to model parameters. The acronym BERRU stands for “Best-Estimate Results with Reduced Uncertainties” and the last letter (“P”) in the acronym indicates “probabilistic,” referring to the MaxEnt probabilistic inclusion of the computational model responses. This is in contradistinction to the 2<sup>nd</sup>-BERRU-PMD methodology, which deterministically combines the computed model responses with the experimental information, as presented in the accompanying work (Part I). Although both the 2<sup>nd</sup>-BERRU-PMP and the 2<sup>nd</sup>-BERRU-PMD methodologies yield expressions that include second (and higher) order sensitivities of responses to model parameters, the respective expressions for the predicted responses, for the calibrated predicted parameters and for their predicted uncertainties (covariances), are not identical to each other. Nevertheless, the results predicted by both the 2<sup>nd</sup>-BERRU-PMP and the 2<sup>nd</sup>-BERRU-PMD methodologies encompass, as particular cases, the results produced by the extant data assimilation and data adjustment procedures, which rely on the minimization, in a least-square sense, of a user-defined functional meant to represent the discrepancies between measured and computed model responses. 展开更多
关键词 second-order Predictive Modeling Data Assimilation Data Adjustment Uncertainty Quantification Reduced Predicted Uncertainties
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Second-Order MaxEnt Predictive Modelling Methodology. III: Illustrative Application to a Reactor Physics Benchmark
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作者 Ruixian Fang Dan Gabriel Cacuci 《American Journal of Computational Mathematics》 2023年第2期295-322,共28页
This work illustrates the innovative results obtained by applying the recently developed the 2<sup>nd</sup>-order predictive modeling methodology called “2<sup>nd</sup>- BERRU-PM”, where the ... This work illustrates the innovative results obtained by applying the recently developed the 2<sup>nd</sup>-order predictive modeling methodology called “2<sup>nd</sup>- BERRU-PM”, where the acronym BERRU denotes “best-estimate results with reduced uncertainties” and “PM” denotes “predictive modeling.” The physical system selected for this illustrative application is a polyethylene-reflected plutonium (acronym: PERP) OECD/NEA reactor physics benchmark. This benchmark is modeled using the neutron transport Boltzmann equation (involving 21,976 uncertain parameters), the solution of which is representative of “large-scale computations.” The results obtained in this work confirm the fact that the 2<sup>nd</sup>-BERRU-PM methodology predicts best-estimate results that fall in between the corresponding computed and measured values, while reducing the predicted standard deviations of the predicted results to values smaller than either the experimentally measured or the computed values of the respective standard deviations. The obtained results also indicate that 2<sup>nd</sup>-order response sensitivities must always be included to quantify the need for including (or not) the 3<sup>rd</sup>- and/or 4<sup>th</sup>-order sensitivities. When the parameters are known with high precision, the contributions of the higher-order sensitivities diminish with increasing order, so that the inclusion of the 1<sup>st</sup>- and 2<sup>nd</sup>-order sensitivities may suffice for obtaining accurate predicted best- estimate response values and best-estimate standard deviations. On the other hand, when the parameters’ standard deviations are sufficiently large to approach (or be outside of) the radius of convergence of the multivariate Taylor-series which represents the response in the phase-space of model parameters, the contributions stemming from the 3<sup>rd</sup>- and even 4<sup>th</sup>-order sensitivities are necessary to ensure consistency between the computed and measured response. In such cases, the use of only the 1<sup>st</sup>-order sensitivities erroneously indicates that the computed results are inconsistent with the respective measured response. Ongoing research aims at extending the 2<sup>nd</sup>-BERRU-PM methodology to fourth-order, thus enabling the computation of third-order response correlations (skewness) and fourth-order response correlations (kurtosis). 展开更多
关键词 second-order Predictive Modeling OECD/NEA Reactor Physics Benchmark Data Assimilation Best-Estimate Results Uncertainty Quantification Reduced Predicted Uncertainties
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Expanding the liver donor pool worldwide with hepatitis C infected livers, is it the time?
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作者 Mai Hashem Mohammed A Medhat +1 位作者 Doaa Abdeltawab Nahed A Makhlouf 《World Journal of Transplantation》 2024年第2期13-27,共15页
Liver transplantation(LT)provides a life-saving option for cirrhotic patients with complications and hepatocellular carcinoma.Despite the increasing number of liver transplants performed each year,the number of LT can... Liver transplantation(LT)provides a life-saving option for cirrhotic patients with complications and hepatocellular carcinoma.Despite the increasing number of liver transplants performed each year,the number of LT candidates on the waitlist remains unchanged due to an imbalance between donor organ supply and the demand which increases the waitlist time and mortality.Living donor liver transplant had a great role in increasing the donor pool and shortened waitlist time for LT candidates.Nevertheless,further strategies can be implemented to increase the pool of potential donors in deceased donor LT,such as reducing the rate of organ discards.Utilizing hepatitis C virus(HCV)seropositive liver grafts is one of the expanded donor organ criteria.A yearly increase of hundreds of transplants is anticipated as a result of maximizing the utilization of HCV-positive organs for HCV-negative recipients.Direct-acting antiviral therapy's efficacy has revolutionized the treatment of HCV infection and the use of HCV-seropositive donors in transplantation.The American Society of Transplantation advises against performing transplants from HCV-infected liver donors(D+)into HCV-negative recipient(R-)unless under Institutional Review Board-approved study rules and with full informed consent of the knowledge gaps associated with such transplants.Proper selection of patients to be transplanted with HCV-infected grafts and confirming their access to direct-acting antivirals if needed is im-portant.National and international consensuses are needed to regulate this process to ensure the maximum benefit and the least adverse events. 展开更多
关键词 Donor pool Hepatitis C-viremic organs Non-viremic organs Direct acting antivirals Hepatitis C virus treated Liver transplantation
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辛空间的排列问题及具有容错能力的pooling设计的紧界 被引量:9
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作者 赵向会 李莉 张更生 《数学物理学报(A辑)》 CSCD 北大核心 2012年第2期414-423,共10页
该文利用辛空间上的子空间构造了一类新的d^z析取矩阵,然后研究了如下排列问题:对于给定的整数m,r,s,v,d,q和辛空间F_q^(2v)中的一个(m,s)型子空间S,这里v+s≥m>r≥2s-1≥1,d≥2,q是一个素数的幂,作者从S中找到d个(m-1,s-1)型子空间H... 该文利用辛空间上的子空间构造了一类新的d^z析取矩阵,然后研究了如下排列问题:对于给定的整数m,r,s,v,d,q和辛空间F_q^(2v)中的一个(m,s)型子空间S,这里v+s≥m>r≥2s-1≥1,d≥2,q是一个素数的幂,作者从S中找到d个(m-1,s-1)型子空间H_1,…H_d,使包含在这些(m-1,s-1)型子空间中的(r,s-1)型子空间个数达到最大.然后利用这个排列的有关结论,给出了一类pooling设计的紧界. 展开更多
关键词 pooling设计 d^z析取 辛空间 排列问题 紧界
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利用伪辛子空间构造的一类pooling设计及其纠错能力的紧界分析 被引量:1
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作者 赵向会 刘铭 张更生 《河北师范大学学报(自然科学版)》 CAS 2015年第5期369-373,共5页
利用伪辛空间上的子空间构造了一类新的dz-析取矩阵,证明了它的析取性,讨论了反映dz-析取矩阵纠错能力z值的紧界.
关键词 pooling设计 dz-析取 伪辛空间 紧界
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基于DNA pooling技术的全基因组关联研究筛选主动脉夹层等位基因遗传位点 被引量:1
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作者 陈逸飞 钟诗龙 +3 位作者 罗建方 薛凌 黎明 胡孜阳 《实用医学杂志》 CAS 北大核心 2012年第20期3405-3407,共3页
目的:筛选与主动脉夹层发病机制相关的遗传易感基因。方法:从主动脉夹层患者(150例)及对照组(250例)外周血白细胞提取基因组DNA,采用DNA Pooling为基础的Illumina Human660W-Quad芯片扫描,筛选与主动脉夹层发病相关的遗传易感基因。结果... 目的:筛选与主动脉夹层发病机制相关的遗传易感基因。方法:从主动脉夹层患者(150例)及对照组(250例)外周血白细胞提取基因组DNA,采用DNA Pooling为基础的Illumina Human660W-Quad芯片扫描,筛选与主动脉夹层发病相关的遗传易感基因。结果:(1)对照组女性数量明显多于病例组(P<0.01);年龄、吸烟、高血压、糖尿病人数无统计学差异(P>0.05)。(2)遗传变异位点SNPrs2298491(位于TBCEL基因),SNP rs6080720(位于BFSP1基因),SNP rs7653410(位于SNTN基因),SNP rs2345106(位于COLQ基因)和位于ABCA13基因上的SNPrs4024044可能与主动脉夹层的发病有关。结论:SNPsrs2298491,rs6080720,rs7653410,rs2345106和rs4024044可能是主动脉夹层发病机制相关遗传变异位点的一部分。 展开更多
关键词 主动脉夹层 DNA pooling 单核苷酸多态性 全基因组关联研究 基因
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奇特征正交空间上可检错Pooling设计的构作 被引量:1
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作者 赵燕冰 刘志刚 《湖南理工学院学报(自然科学版)》 CAS 2009年第3期16-18,共3页
Pooling设计的数学模型是一个d-disjunct矩阵.利用奇特征正交空间中全迷向子空间构作了d-disjunct矩阵,并通过计算它的Hamming距离分析了它的检纠错能力,根据Kautz-Singleton定理对d的范围作了估算.
关键词 奇特征正交空间 全迷向子空间 pooling设计 D-DISJUNCT矩阵 HAMMING距离 检错 纠错
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基于Risk Pooling的Supply Hub库存优势分析 被引量:9
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作者 马士华 梅晚霞 《物流技术》 2008年第8期68-71,85,共5页
采用Risk Pooling的原理分析了Supply Hub运作模式相对于VMI分散运作模式给供应链带来优势。Supply Hub运作模式与VMI分散运作模式在同时向下游供应产品时,Supply Hub运作模式能以更低的安全库存和更少的库存成本来提供与VMI分散运作模... 采用Risk Pooling的原理分析了Supply Hub运作模式相对于VMI分散运作模式给供应链带来优势。Supply Hub运作模式与VMI分散运作模式在同时向下游供应产品时,Supply Hub运作模式能以更低的安全库存和更少的库存成本来提供与VMI分散运作模式相同的服务水平。而且,Hub的规模越大,Supply Hub运作模式的这些优势就越明显。 展开更多
关键词 聚集效应 供应集配商 供应商管理库存
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Pooling PCR技术用于发现病程早期HIV感染者的研究 被引量:3
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作者 唐翼龙 易志强 +4 位作者 刘丽萍 靳廷丽 张娜 丁晨 廖清华 《实验与检验医学》 CAS 2019年第4期565-567,572,共4页
目的研究探讨PoolingPCR技术诊断识别病程早期(急性感染期)艾滋病病毒感染者的能力,并评估该方法是否经济可行、是否可以在部分人群的艾滋病病毒感染状态的诊断中取代艾滋病抗体检测方法。方法收集4家医疗机构留存的4类人群的HIV抗体阴... 目的研究探讨PoolingPCR技术诊断识别病程早期(急性感染期)艾滋病病毒感染者的能力,并评估该方法是否经济可行、是否可以在部分人群的艾滋病病毒感染状态的诊断中取代艾滋病抗体检测方法。方法收集4家医疗机构留存的4类人群的HIV抗体阴性血样,对血样进行PoolingPCR法检测,并计算人均检测成本。结果男男同性恋人群HIV核酸阳性率为554.27/万,性病门诊就诊者人群次之,为不低于119.13/万,体检人群没有发现HIV核酸阳性;医疗机构1(结核病防治机构)的其他就诊者人群核酸阳性率(≥85.54/万)要高于医疗机构2的其他就诊者人群(≥21.04/万)。4个医疗卫生机构所留存的4类人群的抗体检测阴性样本中有2类人群检出HIV病毒核酸阳性,共检出病程早期(HIV抗体阴性,但核酸阳性)样本3例,其中男男同性恋人群检出2例、性病门诊就诊者人群检出1例。结论PoolingPCR检测技术方法敏感且经济,适合于在男男同性恋、性病门诊就诊者及结核病病人等HIV高危人群/高度可疑病人中发现病程早期HIV病毒感染者。 展开更多
关键词 集合核酸定性检测 艾滋病病毒 男男同性恋 性病门诊就诊者 其他就诊者
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Second-Order Raman Scattering from n- and p-Type 4H-SiC
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作者 高欣 孙国胜 +4 位作者 李晋闽 王雷 赵万顺 张永新 曾一平 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第12期1555-1560,共6页
The results of second-order Raman-scattering experiments on n- and p-type 4H-SiC are presented,covering the acoustic and the optical overtone spectral regions.Some of the observed structures in the spectra are assigne... The results of second-order Raman-scattering experiments on n- and p-type 4H-SiC are presented,covering the acoustic and the optical overtone spectral regions.Some of the observed structures in the spectra are assigned to particular phonon branches and the points in the Brillouin zone from which the scattering originates.There exists a doublet at 626/636cm -1 with energy difference about 10cm -1 in both n- and p-type 4H-SiC,which is similar to the doublet structure with the same energy difference founded in hexagonal GaN,ZnO, and AlN.The cutoff frequency at 1926cm -1 of the second-order Raman is not the overtone of the A 1(LO) peak of the n-type doping 4H-SiC,but that of the undoping one.The second-order Raman spectrum of 4H-SiC can hardly be affected by doping species or doping density. 展开更多
关键词 H-SiC second-order Raman cutoff frequency
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