期刊文献+
共找到18篇文章
< 1 >
每页显示 20 50 100
Online 3D Packing Problem Based on Bi-Value Guidance 被引量:1
1
作者 Mingkai Qi Liye Zhang 《Journal of Computer and Communications》 2023年第7期156-173,共18页
The online 3D packing problem has received increasing attention in recent years due to its practical value. However, the problem itself possesses some peculiar properties, such as sequential decision-making and the la... The online 3D packing problem has received increasing attention in recent years due to its practical value. However, the problem itself possesses some peculiar properties, such as sequential decision-making and the large size of the state space, which have made the use of reinforcement learning with Markov decision processes a popular approach for solving this problem. In this paper, we focus on the problem of high variance in value estimation caused by reward uncertainty in the presence of highly uncertain dynamics. To address this, proposed a solution based on auxiliary tasks and intrinsic rewards for the online 3D bin packing problem, guided by a binary-valued network, to assist the agent in learning the policy within the framework of actor-critic deep reinforcement learning. Specifically, the maintenance of two-valued networks and the utilization of multi-valued network estimates are employed to replace the original value estimates, aiming to provide better guidance for the learning of policy networks. Experimentally, it has been demonstrated that our model can achieve more robust learning and outperform previous works in terms of performance. 展开更多
关键词 Deep Learning Reinforcement Learning Bin Packing value Estimation
下载PDF
Relation between the Actual and Estimated Maximum Ground Level Concentration of Air Pollutant and Its Downwind Locations
2
作者 Khaled S. M. Essa Soad M. Etman Maha S. El-Otaify 《Open Journal of Air Pollution》 2020年第2期27-35,共9页
In this work we used the Gaussian plume model to calculate the actual maximum ground level concentration (MGLC) of air pollutant and its downwind location by using different systems of dispersion parameters and for di... In this work we used the Gaussian plume model to calculate the actual maximum ground level concentration (MGLC) of air pollutant and its downwind location by using different systems of dispersion parameters and for different stack heights. An approximate formula for the prediction of downwind position that produces the MGLC of a pollutant based on the Gaussian formula was derived for different diffusion parameters. The derived formula was used to calculate the approximate MGLC. The actual and estimated values are presented in tables. The comparison between the actual and estimated values was investigated through the calculation of the relative errors. The values of the relative errors between the actual and estimated MGLC lie in the range from: 0 to 70.2 and 0 to 1.6 for Pasquill Gifford system and Klug system respectively. The errors between the actual and estimated location of the MGLC lies in the range from: 0.2 to 227 and 0.7 to 9.4 for Pasquill Gifford system and Klug system respectively. 展开更多
关键词 Gaussian Plume Model Actual and estimated values Relative Errors
下载PDF
Estimation of Biodiversity Conservation Value of Forest Ecosystem in Nyingchi Prefecture of Tibet
3
作者 Jia TANG Zhilan CHEN Jiangping FANG 《Asian Agricultural Research》 2017年第2期62-65,共4页
The estimation was made for the conservation value of forest ecosystem biodiversity in Nyingchi Prefecture of Tibet.The results showed that the annual economic benefits of biodiversity in Nyingchi Prefecture were abou... The estimation was made for the conservation value of forest ecosystem biodiversity in Nyingchi Prefecture of Tibet.The results showed that the annual economic benefits of biodiversity in Nyingchi Prefecture were about 21.4 billion yuan,and the annual economic benefits of global biodiversity were about 3 trillion USD.It indicated that the ecological value of forest ecosystem in Nyingchi Prefecture is high,forest ecosystem has extremely important ecological value.Therefore,in the decision-making process,it is necessary to strengthen the protection of forest ecosystem,with particular emphasis on the restoration of damaged ecosystem. 展开更多
关键词 BIODIVERSITY value estimation Forest ecosystem Nyingchi Prefecture
下载PDF
Ultrasonic attenuation estimation based on time-frequency analysis 被引量:3
4
作者 Gao Feng Wei Jian-Xin Di Bang-Rang 《Applied Geophysics》 SCIE CSCD 2019年第4期414-426,559,共14页
The quality factor(or Q value)is an important parameter for characterizing the inelastic properties of rock.Achieving a Q value estimation with high accuracy and stability is still challenging.In this study,a new meth... The quality factor(or Q value)is an important parameter for characterizing the inelastic properties of rock.Achieving a Q value estimation with high accuracy and stability is still challenging.In this study,a new method for estimating ultrasonic attenuation using a spectral ratio based on an S transform(SR-ST)is presented to improve the stability and accuracy of Q estimation.The variable window of ST is used to solve the time window problem.We add two window factors to the Gaussian window function in the ST.The window factors can adjust the scale of the Gaussian window function to the ultrasonic signal,which reduces the calculation error attributed to the conventional Gaussian window function.Meanwhile,the frequency bandwidth selection rules for the linear regression of the amplitude ratio are given to further improve stability and accuracy.First,the feasibility and influencing factors of the SR-ST method are studied through numerical testing and standard sample experiments.Second,artificial samples with different Q values are used to study the adaptability and stability of the SR-ST method.Finally,a further comparison between the new method and the conventional spectral ratio method(SR)is conducted using rock field samples,again addressing stability and accuracy.The experimental results show that this method will yield an error of approximately 36%using the conventional Gaussian window function.This problem can be solved by adding the time window factors to the Gaussian window function.The frequency bandwidth selection rules and mean slope value of the amplitude ratio used in the SR-ST method can ensure that the maximum error of different Q values estimation(Q>15)is less than 10%. 展开更多
关键词 Q value estimation Time-frequency spectrum ST Window factor Ultrasonic attenuation
下载PDF
Analysis of phenotypic and genetic parameters for growth-related traits in the half smooth tongue sole,Cynoglossus semilaevis 被引量:2
5
作者 刘峰 李仰真 +2 位作者 杜民 邵长伟 陈松林 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第1期163-169,共7页
Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole, Cynoglossus semilaevis, were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic... Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole, Cynoglossus semilaevis, were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic males with female genotypes, neo-males are harmful in C. semilaevis aquaculture because they reduce overall production. The present study evaluated the difference in the growth-related traits: total length (TL), body weight (BW) and square root of body weight (SQ_BW) at the age of 570 days between normal and neo-male offspring (neo-males used as male parents). The difference in the proportion of females between normal and neo-male offspring was also assessed. Based on the linear mixed model, restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP) were used to estimate various (co)variance components and estimated breeding values (EBVs) of growth-related traits. As a result, all the mean values of the three studied traits were significantly larger in normal offspring than in neo-male offspring. Additionally, the female proportion was significantly larger in normal offspring than in neo-male offspring. Heritability was 0.128+0.066 2 for TL, 0.128-4-0.065 5 for BW and 0.132~0.062 9 for SQBW, all of which were low level heritabilities. The correlation coefficients of EBVs and phenotypic values of the target traits were 0.516 for TL, 0.524 for BW and 0.506 for SQ_BW, all of which were highly significant (P〈0.01). Genetic correlations among TL, BW and SQ_BW were positive high (0.921-0.969) and higher than those of phenotype (0.711-0.748), both of which had low standard errors (0.063-0.123 for genotype, and 0.010-0.018 for phenotype). Compared with normal offspring, neo-male offspring have lower breeding values for each studied trait through EBVs comparison. Therefore, neo-male offspring should not be used as broodstock in a C. semilaevis breeding programs. 展开更多
关键词 Cynoglossus semilaevis estimated breeding value (EBV) HERITABILITY genetic correlation
下载PDF
Multilinear Calderón-Zygmund Operators and Their Commutators with BMO Functions in Herz-Morrey Spaces with Variable Smoothness and Integrability 被引量:1
6
作者 hu yuan-zhu xu jing-shi ji you-qing 《Communications in Mathematical Research》 CSCD 2017年第3期238-258,共21页
In this paper, we obtain that multilinear Calderón-Zygmund operators and their commutators with BMO functions are bounded on products of Herz-Morrey spaces with variable smoothness and integrability. The vector-v... In this paper, we obtain that multilinear Calderón-Zygmund operators and their commutators with BMO functions are bounded on products of Herz-Morrey spaces with variable smoothness and integrability. The vector-valued setting of multilinear Calderón-Zygmund operators is also considered. 展开更多
关键词 multilinear Calderón-Zygmund operator variable exponent Herz-Morrey space vector valued estimate
下载PDF
Estimation of dynamic stress spectrum distribution in structural fatigue test
7
作者 Guangjin Xue Kai Li +3 位作者 Wu Pan Qiang Li Bingjie Wang Shouguang Sun 《Theoretical & Applied Mechanics Letters》 CAS 2013年第2期51-56,共6页
The determination of structural dynamic stress spectrum distribution is of great signifi- cance in the structural fatigue strength evaluation as well as reliability design. In previous empirical data processing method... The determination of structural dynamic stress spectrum distribution is of great signifi- cance in the structural fatigue strength evaluation as well as reliability design. In previous empirical data processing methods, the data grouping and distribution fitting were excessively coarse and contained distinctive defects. This paper proposed an effective approach to statistically group actual measured dynamic stress data and validly extrapolate the combined distribution to fit the dynamic stress spectrum distribution. This approach has been verified its effectiveness through chi-square test, stress spectrum extrapolation and damage calculation in dynamic stress study. 展开更多
关键词 data grouping combined distribution damage calculation maximum value estimation stress spectrum extrapolation
下载PDF
Research on Leak Location of Liquid-filled Pipe Based on Frequency Dispersion Characteristics
8
作者 Lijun XIONG Ping LU +1 位作者 Yun YANG Li LI 《Mechanical Engineering Science》 2021年第1期19-27,共9页
Due to the material problems and force majeure factors,the leakage will be occurred on the liquid-filled pipe resulting in waste of resources,environmental pollution and even endangering safety.Acoustic wave detection... Due to the material problems and force majeure factors,the leakage will be occurred on the liquid-filled pipe resulting in waste of resources,environmental pollution and even endangering safety.Acoustic wave detection technology is widely used in buried pipeline leak detection,this technology mainly uses the wave(n=0,s=1)in the pipeline acoustic wave to locate the leak.When the leakage acoustic signal propagates along the liquid-filled pipe,the frequency dispersion characteristics can be obtained by wavelet decomposition.And there is a time delay(time difference)value between the leaky acoustic signals collected by the sensors at both ends of the leak.The outputs show that the results obtained by wavelet decomposition are in good agreement with the theoretical calculation results.Based on the obtained dispersion relation,the time delay values at different characteristic frequencies are analyzed by the cross-correlation method,and the leak location accuracy is discussed.This research content provides theoretical support and engineering application guidance for pipe leakage location technology. 展开更多
关键词 Liquid-filled pipe Frequency dispersion characteristics Leak location Time delay estimation value
下载PDF
Comparative study of estimation methods for genomic breeding values 被引量:3
9
作者 Chonglong Wang Qin Zhang +3 位作者 Li Jiang Rong Qian Xiangdong Ding Yaofeng Zhao 《Science Bulletin》 SCIE EI CAS CSCD 2016年第5期353-356,共4页
Estimation of genomic breeding values is important in genomic selection. Bayesian and BLUP methods are the main techniques employed. In this study,we conducted a comparative study of Bayes A, Bayes B,Bayes Cp and GBLU... Estimation of genomic breeding values is important in genomic selection. Bayesian and BLUP methods are the main techniques employed. In this study,we conducted a comparative study of Bayes A, Bayes B,Bayes Cp and GBLUP methods in simulated data and real data of Chinese Holstein cattle. Results showed that, in simulated data, the accuracies of all methods were all similarly elevated with the increase of reference population size, but they made different responses to the changes of marker number or QTL number. In real data of Chinese Holstein cattle, Bayes A generated the highest accuracy almost for all six traits, and GBLUP performed as well as Bayes A for the traits of milk yield, fat yield and protein yield, while for the trait of fat percentage, protein percentage and somatic cell score, three Bayesian methods showed superior to GBLUP. Comprehensively analyzing above results, it can be speculated that accuracies of the three Bayesian methods are not only influenced by the absolute value of QTL number or marker number, but may also be influenced by the ratio of QTL number to marker number. And there is at least one kind of Bayesian methods performing better than GBLUP, when the ratio of QTL number versus marker number is very small or involving large-effect QTL. 展开更多
关键词 Genomic selection Estimation of genomic breeding values Bayesian methods BLUP methods
原文传递
Estimation of maximum inclusion by statistics of extreme values method in bearing steel 被引量:2
10
作者 Chao Tian Jian-hui Liu +1 位作者 Heng-chang Lu Han Dong 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第11期1131-1136,共6页
A statistic method, statistics of extreme values (SEV), was described in detail, which can esti mate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing s... A statistic method, statistics of extreme values (SEV), was described in detail, which can esti mate the size of maximum inclusion in steel. The characteristic size of the maximum inclusion in a high clean bearing steel (GCrl5) was evaluated by this method, and the morphology and corn position of large inclusions found were analyzed by scanning electron microscopy (SEM). When standard inspection area (S0) is 280 mm2, the characteristic size of the biggest inclusion found in 30 standard inspection area is 23.93 μm, and it has a 99.9% probability of the characteristic size of maximum inclusion predicted being no larger than 36.85μm in the experimental steel. SEM result shows that large inclusions found are mainly composed of CaS, calcium-aluminate and MgO. Compositing widely exists in large inclusions in high clean bearing steel. Compared with traditional evaluation method, SEV method mainly focuses on inclusion size, and the esti- mation result is not affected by inclusion types. SEV method is suitable for the inclusion eval uation of high clean bearing steel. 展开更多
关键词 Nonmetallic inclusion Statistics of extreme values Gumbel distribution function Likelihood function estimation
原文传递
Some Simple Estimates for the Singular Values of Matrices 被引量:4
11
作者 Chuan-long WANG, Guo-jian ZHANGDepartment of Mathematics, Normal College of Shanxi University, Taiyuan 030012, ChinaDepartment of Applied Mathematics, Taiyuan University of Technology, Taiyuan, 030024, China 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2002年第1期117-122,共6页
We first provide a simple estimate for || A-1||∞and||A-1||1 of a strictly diagonally dominant matrix A. On the Basis of the result, we obtain an estimate for the smallest singular value of A. Secondly, by scaling wit... We first provide a simple estimate for || A-1||∞and||A-1||1 of a strictly diagonally dominant matrix A. On the Basis of the result, we obtain an estimate for the smallest singular value of A. Secondly, by scaling with a positive diagonal matrix D, we obtain some simple estimates for the smallest singular value of an H-matrix, which is not necessarily positive definite. Finally, we give some examples to show the effectiveness of the new bounds. 展开更多
关键词 Singular value estimates H-MATRIX
全文增补中
Optimal L_∞ Estimates for Galerkin Methods for Nonlinear Singular Two-point Boundary Value Problems
12
作者 Xu ZHANG Zhong-ci SHI 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2015年第3期719-728,共10页
In this paper, we apply the symmetric Galerkin methods to the numerical solutions of a kind of singular linear two-point boundary value problems. We estimate the error in the maximum norm. For the sake of obtaining fu... In this paper, we apply the symmetric Galerkin methods to the numerical solutions of a kind of singular linear two-point boundary value problems. We estimate the error in the maximum norm. For the sake of obtaining full superconvergence uniformly at all nodal points, we introduce local mesh refinements. Then we extend these results to a class of nonlinear problems. Finally, we present some numerical results which confirm our theoretical conclusions. 展开更多
关键词 singular two-point boundary value problems symmetric Galerkin method maximum norm error estimate superconvergence local mesh refinement
原文传递
Multivariate time series imputation for energy data using neural networks
13
作者 Christopher Bulte Max Kleinebrahm +1 位作者 Hasan Umitcan Yilmaz Juan Gomez-Romero 《Energy and AI》 2023年第3期25-35,共11页
Multivariate time series with missing values are common in a wide range of applications,including energy data.Existing imputation methods often fail to focus on the temporal dynamics and the cross-dimensional correlat... Multivariate time series with missing values are common in a wide range of applications,including energy data.Existing imputation methods often fail to focus on the temporal dynamics and the cross-dimensional correlation simultaneously.In this paper we propose a two-step method based on an attention model to impute missing values in multivariate energy time series.First,the underlying distribution of the missing values in the data is learned.This information is then further used to train an attention based imputation model.By learning the distribution prior to the imputation process,the model can respond flexibly to the specific characteristics of the underlying data.The developed model is applied to European energy data,obtained from the European Network of Transmission System Operators for Electricity.Using different evaluation metrics and benchmarks,the conducted experiments show that the proposed model is preferable to the benchmarks and is able to accurately impute missing values. 展开更多
关键词 Missing value estimation Multivariate time series Neural networks Attention model Energy data
原文传递
On the Third and Fourth Power Moments of Fourier Coefficients of Cusp Forms 被引量:2
14
作者 Cai Yingchun Department of Mathematics, Shandong Normal University, Jinan 250014, China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1997年第4期443-452,共10页
The asymptotic formulae for the third and fourth power moments of Fourier coefficients of cusp forms are proved in this paper.
关键词 Cusp form Fourier coefficients The estimation of mean value Asymptotic formula
原文传递
Controller area network node reliability assessment based on observable node information 被引量:1
15
作者 Lei-ming ZHANG Long-hao TANG Yong LEI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2017年第5期615-626,共12页
Controller area network(CAN) based fieldbus technologies have been widely used in networked manufacturing systems. As the information channel of the system, the reliability of the network is crucial to the system thro... Controller area network(CAN) based fieldbus technologies have been widely used in networked manufacturing systems. As the information channel of the system, the reliability of the network is crucial to the system throughput, product quality, and work crew safety. However, due to the inaccessibility of the nodes' internal states, direct assessment of the reliability of CAN nodes using the nodes' internal error counters is infeasible. In this paper, a novel CAN node reliability assessment method, which uses node's time to bus-off as the reliability measure, is proposed. The method estimates the transmit error counter(TEC) of any node in the network based on the network error log and the information provided by the observable nodes whose error counters are accessible.First, a node TEC estimation model is established based on segmented Markov chains. It considers the sparseness of the distribution of the CAN network errors. Second, by learning the differences between the model estimates and the actual values from the observable node, a Bayesian network is developed for the estimation updating mechanism of the observable nodes. Then, this estimation updating mechanism is transferred to general CAN nodes with no TEC value accessibility to update the TEC estimation. Finally, a node reliability assessment method is developed to predict the time to reach bus-off state of the nodes. Case studies are carried out to demonstrate the effectiveness of the proposed methodology. Experimental results show that the estimates using the proposed model agree well with actual observations. 展开更多
关键词 Controller area network(CAN) Transmit error counter(TEC) TEC value estimation Bayesian network Bus-off hitting time
原文传递
Minimum Time Extrema Estimation for Large-Scale Radio-Frequency Identification Systems
16
作者 Xiao-Jun Zhu Li-Jie Xu +1 位作者 Xiao-Bing Wu Bing Chen 《Journal of Computer Science & Technology》 SCIE EI CSCD 2020年第5期1099-1114,共16页
We consider the extrema estimation problem in large-scale radio-frequency identification(RFID)systems,where there are thousands of tags and each tag contains a finite value.The objective is to design an extrema estima... We consider the extrema estimation problem in large-scale radio-frequency identification(RFID)systems,where there are thousands of tags and each tag contains a finite value.The objective is to design an extrema estimation protocol with the minimum execution time.Because the standard binary search protocol wastes much time due to inter-frame overhead,we propose a parameterized protocol and treat the number of slots in a frame as an unknown parameter.We formulate the problem and show how to find the best parameter to minimize the worst-case execution time.Finally,we propose two rules to further reduce the execution time.The first is to find and remove redundant frames.The second is to concatenate a frame from minimum value estimation with a frame from maximum value estimation to reduce the total number of frames.Simulations show that,in a typical scenario,the proposed protocol reduces execution time by 79%compared with the standard binary search protocol. 展开更多
关键词 radio-frequency identification(RFID)system maximum value estimation minimum value estimation time efficient protocol
原文传递
A Fast Ambient Occlusion Method for Real-Time Plant Rendering
17
作者 滕军 Marc Jaeger 胡包钢 《Journal of Computer Science & Technology》 SCIE EI CSCD 2007年第6期859-866,共8页
Global illumination effects are crucial for virtual plant rendering. Whereas real-time global illumination rendering of plants is impractical, ambient occlusion is an efficient alternative approximation. A tree model ... Global illumination effects are crucial for virtual plant rendering. Whereas real-time global illumination rendering of plants is impractical, ambient occlusion is an efficient alternative approximation. A tree model with millions of triangles is common, and the triangles can be considered as randomly distributed. The existing ambient occlusion methods fail to apply on such a type of object. In this paper, we present a new ambient occlusion method dedicated to real time plant rendering with limited user interaction. This method is a three-step ambient occlusion calculation framework which is suitable for a huge number of geometry objects distributed randomly in space. The complexity of the proposed algorithm is O(n), compared to the conventional methods with complexities of O(n^2). Furthermore, parameters in this method can be easily adjusted to achieve flexible ambient occlusion effects. With this ambient occlusion calculation method, we can manipulate plant models with millions of organs, as well as geometry objects with large number of randomly distributed components with affordable time, and with perceptual quality comparable to the previous ambient occlusion methods. 展开更多
关键词 accessibility value estimation plant visualization real-time rendering
原文传递
Statistical considerations for genomic selection
18
作者 Huimin KANG Lei ZHOU Jianfeng LIU 《Frontiers of Agricultural Science and Engineering》 2017年第3期268-278,共11页
Genomic selection is becoming increasingly important in animal and plant breeding, and is attracting greater attention for human disease risk prediction. This review covers the most commonly used statistical methods a... Genomic selection is becoming increasingly important in animal and plant breeding, and is attracting greater attention for human disease risk prediction. This review covers the most commonly used statistical methods and some extensions of them, i.e., ridge regression and genomic best linear unbiased prediction, Bayesian alphabet, and least absolute shrinkage and selection operator.Then it discusses the measurement of the performance of genomic selection and factors affecting the prediction of performance. Among the measurements of prediction performance, the most important and commonly used measurement is prediction accuracy. In simulation studies where true breeding values are available, accuracy of genomic estimated breeding value can be calculated directly. In real or industrial data studies, either trainingtesting approach or k-fold cross-validation is commonly employed to validate methods. Factors influencing the accuracy of genomic selection include linkage disequilibrium between markers and quantitative trait loci, genetic architecture of the trait, and size and composition of the training population. Genomic selection has been implemented in the breeding programs of dairy cattle, beef cattle, pigs and poultry. Genomic selection in other species has also been intensively researched, and is likely to be implemented in the near future. 展开更多
关键词 genomic estimated breeding value genomic selection linkage disequilibrium statistical methods
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部