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1.
A new method is proposed for the simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert-Huang transform (OHHT) spectra of its sample observations. Orthogonal EMD method is introduced to treat with IMF. OHHT avoids leakage of energy compared with conventional HHT, and it can be used for analysis of nonstationary signal. The average of the Hilbert spectra over the samples is defined as the Hilbert spectrum of the earthquake motion process and used as the target in the simulation of the process. Random Phase is also introduced to simulate nonstationary earthquake. The statistic characteristics function of stochastic process is given in the paper. Simulations of two earthquake ground motion are carried out. The results show that the samples can accurately reflect amplitude and frequency nonstationary of records. Samples and record of same earthquake ground motion process have same statistic characteristics.  相似文献   

2.
The interacting multiple model algorithm is used to solve the vehicle's tracking problems in automated highway system.It has multiple models,each of which matches to a particular mode such as uniform motion with constant velocity and maneuvering motion with acceleration.Combined with the target maneuvering models,the current acceleration of the target and its covariance are simulated.Significant noise reduction is achieved during the uniform motion.And it does better in maintaining the accuracy of the state estimates than the unfiltered radar measurements during the maneuver.A rapid detection of the maneuver is also obtained.The Monte Carlo simulation results show that the IMM algorithm will improve the target's tracking performance and enhance the vehicle's safety and reliability.  相似文献   

3.
The analysis of association mapping populations is frequently complicated by substructure within the population. If this is unaccounted for, it generally results in many false positive marker-trait associations. In this study, we simulate a large barley population, modelling inbreeding and selection, and compare five models for analysing marker-trait associations. One of these includes no population substructure, one includes information about geographical origin and type of barley to represent structure within the population and three use different approaches that have been proposed for estimating marker-based kinship. Kinship methods reduced the number of false positives substantially compared to the other models but none of these approaches had a clear advantage over the others. One solution is to fit more than one model and to consider as candidate associations those markers that are significant by all models. None of the approaches were very successful at detecting true associations at the lowest level of heritability considered (25%), suggesting it is important to consider power in association mapping studies to avoid missing some true associations and overestimating others.  相似文献   

4.
基于NLPCA-RBF神经网络的番茄蒸散量预测   总被引:1,自引:1,他引:0  
蒸散量(ET)是水文循环中的重要组成部分。精确的ET预测在水资源管理和灌溉系统设计等方面的研究是十分必要的。利用非线性主成分分析法(NLPCA)和径向基(RBF)神经网络组成的模型(NLPCA-RBF)对番茄蒸散量进行估算。在既保证ET影响因素信息完整,又可消除影响因素之间相关性的前提下,利用NLPCA将影响ET的7个气象因素简化为3个综合成分,并以此为网络训练的输入数据,根据实测的蒸散量作为网络输出建立了RBF神经网络,并且经非训练样本点数据检验。结果表明,与传统RBF网络模型较,NLPCA-RBF网络预测模型能够更好的反应影响因子与蒸散量之间的关系,取得更为精确的结果。  相似文献   

5.
In order to improve the stabilization effect of dynamic scene video sequences with multiple moving foreground objects, a new method based on block absolute difference is proposed to extract the foreground objects automatically. Based on extracting the moving objects, the background blocks are selected to estimate the motion parameters with the defined threshold, so the background blocks for estimating motion parameters are greatly reduced. For moving scene with multiple moving foreground objects, due to the reduction of the time of extracting moving objects, the simulation results shown that the running time of the proposed method is reduced effectively, the stabilization effect is improved, and more ideal effect is realized compared with the traditional method.  相似文献   

6.
植物在抵抗和适应不良环境时会产生生长缓慢或暂时停顿的休眠现象,打破休眠时所需的有效低温时数称为植物的需冷量。本研究综述了不同需冷量模型并分析了应用情况及效果。Utah模型是目前使用频率较高且效果较好的估算模型,动力学模型是理论最完善且适用范围最广的估算模型,但仍未推广应用,尤其是国内鲜有报道。需冷量估算模型研究对象主要为休眠芽,对其他休眠器官(球根、种子等)的需冷量研究还不多。与果树等其他园艺作物相比,目前将冷量估算模型应用于观赏植物的研究较少,涉及到植物种类和休眠器官类型都较少。需冷量模型与低温小时数相比能更准确计量及预测解除休眠过程对低温的需求,应用于观赏植物品种区域规划、引种有更好的前景。同时,继续探索需冷量累积的过程中相关的生物学机制,优化需冷量模型使其在不同气候类型中的应用具有通用型是未来研究需要着力解决的问题。  相似文献   

7.
WEB(Web based Network Management) is new trend of Network Management.Features of WBM and related international standards are described.AI environment integrates with WBM is the next trend of network management too.Integrated and intelligent WBM system will be developed in the futare.  相似文献   

8.
Sugarcane is known for its highly complex genetics and more knowledge is needed for better use and conservation of genetic materials. In order to identify genotypes and to assess genetic diversity, diverse data sets such as morphological and molecular markers are used as a general approach. To evaluate the usefulness of different markers, important sugarcane genotypes in Argentina were characterized by AFLP, SSR and morphological traits. All genotypes characterized were grouped in one main cluster in dendrograms using two independent softwares. Interestingly, local genotypes grouped together with USA varieties and no clear genetic differentiation could be found probably due to intensive germplasm exchange between these breeding programs. The molecular markers tested were useful for genetic diversity assessment as well as for genotype identification. These markers should be included in the internationally established characters for sugarcane variety protection as they give a better view on whole genome complexity. Additionally, genetic similarities obtained from molecular markers will provide more accurate information to breeders than the pedigree method, especially when considering the asymmetric genetic inheritance of sugarcane. Morphological traits are valuable tools to identify genotypes since they reflect external resemblance more than genetic relatedness. When they were combined with molecular markers the dendogram obtained revealed genetic relationships and the genetic diversity was better estimated. In summary, both methods appear to be useful, complementing each other and should be used together to assist sugarcane breeders in estimating genetic diversity, electing parents for crossings, identifying superior lines and to protect intellectual property rights.  相似文献   

9.
In this paper, the basic requirements for the suitability of the amplitude definitions of strong ground motion for engineering purpose are presented and brief comments on the definitions of amplitude of strong ground motion now widely used are given accordingly. The effects of different definitions of amplitude of strong ground motions on different structural response indexes of SDOF systems are discussed by dynamic time-history analysis.  相似文献   

10.
水稻株高性状对大气CO2浓度升高的响应   总被引:2,自引:0,他引:2  
以粳稻品种Asominori与籼稻品种IR24的杂交组合所衍生的染色体片段置换系(CSSLs)为材料,田间试验分别在FACE(CO2浓度约570 µmol mol-1)和对照(CO2浓度约370 µmol mol-1)下,对水稻株高性状的数量性状位点(QTL)进行了分析。结果表明,Asominori和IR24的株高、穗长、上位第一节间长和上位第二节间长在FACE和对照下的差异达显著水平;供试株系的4个株高性状对CO2浓度升高都呈正负两种响应,其变化最大的株系为AI7和AI44(株高分别增加14.2 cm和降低4.54 cm),AI9和AI12(穗长分别增加3.56 cm和降低2.39 cm),AI39和AI27(上位第一节间长分别增加15.74 cm和降低1.49 cm),AI32和AI53(上位第二节间长分别增加8.09 cm和降低3.00 cm);FACE和对照下分别检测出14和15个QTL,分布在除第2、7、9和第10号染色体外的各染色体上,其中5个(qPH6-4、qPH8-4、qPL8-4、qPL12-4和qLFN6-4)在FACE和对照条件下同时检测到,分布在第6、8和第12染色体上,而其余的只在FACE或对照下检测到。这29个QTLs中,3个(qPH6-4QE、qPH8-4QE和qLSN5-4QE)具显著的基因型与环境互作。在不同的CO2环境下,测试性状发生不同程度的表型变异。结果推论,对CO2浓度增加敏感的QTL位点,可能受到CO2浓度增加的诱导,可见控制水稻株高性状的QTL与CO2增加的环境发生了互作效应。  相似文献   

11.
大丽轮枝菌是广泛分布的土壤习居菌,能引起棉花黄萎病害,因其形成的微菌核生命力强,可在土壤中存活多年,是大丽轮枝菌型黄萎病的主要初侵染来源。为开展微菌核的研究,本试验对微菌核形成最佳培养基进行了筛选,采用6种培养基,培养6株大丽轮枝菌(Verticillium dahliae Kleb.),通过生长速率、微菌核数量、微菌核直径和微菌核萌发率4项指标筛选合适的培养基。结果表明:改良燕麦培养基形成微菌核的数量和直径均优于其他培养基;M1和BMM培养基形成微菌核的数量较多,其微菌核直径均小于半组合培养基。因此,改良燕麦、M1和BMM培养基,根据实验需要均可作为快速培养微菌核的理想培养基。  相似文献   

12.
Incomplete information of the poker games make the research progress lags behind the chess games in AI. Although it is still very difficult to find a fast algorithm to solve a poker game with complete information which is the foundation of some advance researches. This paper gives a standard way to encode and store a game state into hash table, so the memory of hash table can be used more effectively and higher hit rate can be gotten in Scout search meth od. With the new encoding method, the total expanding leaf nodes reduces by around 5%.  相似文献   

13.
ABSTRACT The purpose of this paper is to review recent developments in economics and public policy with regard to environmental resources. We describe the traditional concepts of externalities, public goods, efficient property rights, and the more recent concept of existence values for wilderness areas and other natural resources. A feature is the inclusiveness of modem economic theory. We trace the development of economic approaches to estimating values. We briefly review approaches based on observable market behavior and contingent market responses. Contingent valuation plays a vital role in estimation because it is the sole technique available for estimating the potentially important existence values. Benefit-cost analysis for regulatory decisions and natural resource damages assessment for implementation of Superfund legislation are discussed. We conclude that estimates of existence values based on contingent valuation can be useful especially when the alternative is greater reliance upon an imperfect political process.  相似文献   

14.
Common bean (Phaseolus vulgaris L.) improvement programs have been successful using conventional breeding methods to accomplish a wide array of important objectives. Specific achievements include the extension of range of adaptation of the crop, the development of cultivars with enhanced levels of disease and pest resistance and breeding lines that possess greater tolerance to drought. The most effective breeding method depends on the expression and inheritance of the trait to be selected and the target environment. Many bean improvement programs use molecular markers to facilitate cultivar development. In fact, several recent germplasm releases have used molecular markers to introgress and or pyramid major genes and QTL for disease resistance. Related species (P. coccineus and P. acultifolius) via interspecific hybridizations remain an important albeit long-term source for resistance to economically important diseases. Slow progress has been made in the improvement of traits such as adaptation to low soil fertility and tolerance to high levels of soluble Al in the soil using conventional breeding methods. The inability to directly measure root traits and the importance of genotype × environment interaction complicate the selection of these traits. In addition, symbiotic relationships with Rhizobium and mycorrhiza need to be taken into consideration when selecting for enhanced biological N fixation and greater or more efficient acquisition of soil P. Genomic examination of complex traits such as these should help bean breeders devise more effective selection strategies. As integration of genomics in plant breeding advances, the challenge will be to develop molecular tools that also benefit breeding programs in developing countries. Transgenic breeding methods for bean improvement are not well defined, nor efficient, as beans are recalcitrant to regeneration from cell cultures. Moreover, if issues related to consumer acceptance of GMOs cannot be resolved, traits such as herbicide tolerance in transgenic bean cultivars which would help farmers reduce production costs and decrease soil erosion will remain unrealized.  相似文献   

15.
Test and Measurement task can be done without limit of time and space by PDA with virtual instrument technology. The structure of PDA based virtual instrument is described firstly. Then PMDS(PDA Measurement Develop System) which can construct virtual instruments efficiently using component technology is introduced, it can enhance quality and efficiency of instruments. Finally, portable spectrum analyzer and mobile temperature monitor is built with PMDS to illuminate the usage of PMDS.  相似文献   

16.
Flowering time is a key trait in the plant life cycle and an important selection criterion for soybean. Here, we combine the advantages of genome-wide association and linkage mapping to identify and fine map quantitative trait loci (QTLs) associated with flowering time. Linkage mapping was performed using 152 recombinant inbred lines and a major QTL, qFT6, affecting flowering time was found on chromosome 6. To refine the qFT6, the 192 natural accessions were genotyped using eight new simple sequence repeats and 10 single nucleotide polymorphisms markers covering the qFT6 region Haplotype analysis showed that the haplotype between markers BARC-014947-01929 and Satt365 could explain more phenotypic variation (26.5 %) than any other combination of markers. These results suggested that the target flowering time gene was located in ~300 kb between BARC-014947-01929 and Satt365, including three predicted genes. High-resolution map in qFT6 region will be useful not only for marker-assisted selection of flowering time but also for further positional cloning of the target gene. These results indicate that combining association and linkage mapping provides an efficient approach for fine mapping of soybean genes.  相似文献   

17.
以粳稻品种Asominori与籼稻品种IR24的杂交组合所衍生的染色体片段置换系(CSSLs)为材料,田间试验分别在FACE(CO2浓度约570 µmol mol-1)和对照(CO2浓度约370 µmol mol-1)下,对水稻株高性状的数量性状位点(QTL)进行了分析。结果表明,Asominori和IR24的株高、穗长、上位第一节间长和上位第二节间长在FACE和对照下的差异达显著水平;供试株系的4个株高性状对CO2浓度升高都呈正负两种响应,其变化最大的株系为AI7和AI44(株高分别增加14.2 cm和降低4.54 cm),AI9和AI12(穗长分别增加3.56 cm和降低2.39 cm),AI39和AI27(上位第一节间长分别增加15.74 cm和降低1.49 cm),AI32和AI53(上位第二节间长分别增加8.09 cm和降低3.00 cm);FACE和对照下分别检测出14和15个QTL,分布在除第2、7、9和第10号染色体外的各染色体上,其中5个(qPH6-4、qPH8-4、qPL8-4、qPL12-4和qLFN6-4)在FACE和对照条件下同时检测到,分布在第6、8和第12染色体上,而其余的只在FACE或对照下检测到。这29个QTLs中,3个(qPH6-4QE、qPH8-4QE和qLSN5-4QE)具显著的基因型与环境互作。在不同的CO2环境下,测试性状发生不同程度的表型变异。结果推论,对CO2浓度增加敏感的QTL位点,可能受到CO2浓度增加的诱导,可见控制水稻株高性状的QTL与CO2增加的环境发生了互作效应。  相似文献   

18.
培养基对尖孢镰刀菌非致病力菌株281产孢量的影响   总被引:1,自引:0,他引:1  
选择8种培养基,采用液体培养法,研究培养基质对尖孢镰刀菌(Fusarium oxysporum Schl.)281菌株小孢子产生量的影响,结果表明,在PDA培养基上培养144h得到最大小孢子产量1.283×109cfu/ml,与其它培养基产孢量差异显著(P=0.05)。培养至192h时,ATCC培养基的小孢子数量达到1.325×109cfu/ml,与PDA培养基之间无显著差异(P=0.05),与其它6种培养基之间差异显著(P=0.05)。综合比较8种培养基,PDA培养基培养时间短,配制简单,是较为理想的产小孢子培养基。  相似文献   

19.
Genomewide association study (GWAS), which queries the association between loci and a particular trait by examining single nucleotide polymorphisms (SNPs) of the entire genome, is used in many fields of study. The development of next‐generation sequencing techniques has facilitated GWASs by decreasing the sequencing costs and time. In particular, genotyping by sequencing (GBS) is useful for sequencing many samples simultaneously and at a moderate price. Herein, we describe a potential GWAS using GBS, focused on the apple germplasm, with the goal of developing an effective apple breeding strategy through the identification of useful markers. From 308 Korean apple germplasm, SNPs were selected after GBS, and major traits were investigated. Proprietary individuals were confirmed and grouped by association through genetic diversity and population structure analyses of the selected SNPs. Genes highly associated with the target traits were identified, respectively. As the first GWAS report on the apple germplasm, these results will be useful as base data for GWASs on other apple populations and traits.  相似文献   

20.
P. Annicchiarico    C. Royo    F. Bellah    M. Moragues 《Plant Breeding》2009,128(2):164-171
Breeding for specific or wide adaptation would be more cost-efficient if preliminary indications on genotype adaptive responses could be provided by easily-detectable morphophysiological or molecular characteristics. We investigated the consistency among adaptation parameters, morphophysiological traits and SSR markers in estimating and structuring the genetic diversity among 24 durum wheat genotypes. Additive main effects and multiplicative interaction adaptation parameters were estimated across 14 Algerian locations belonging to a low- or a high-elevation subregion. Eight morphophysiological traits were assessed in two locations per subregion. Genotype Euclidean distances based on adaptation parameters were closely related to those based on morphophysiological traits ( r  = 0.75, P = 0.01). Marker-based distances exhibited low correlation with those based on adaptation parameters ( r  = 0.26, P = 0.01) or morphophysiological traits ( r  = 0.32). The consistency between adaptation parameters and morphophysiological traits for genotype ordination and classification was greater than that between either information layer and SSR markers. Optima of phenology and plant height differed between subregions, whereas many kernels per spike and fertile tillers were associated with adaptation to both subregions.  相似文献   

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