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1.
建构竞争相似性衡量模型Competitive Similarity Measurement Model(CSMM)模型,有助于辨识厂商间对抗关系。主要探讨动态竞争的竞争者图像,以市场共同性及资源相似性为基,整合竞争相似性衡量方法,来计算厂商之间的竞争相似性认知程度差异值。依据CSMM衡量模式,以台湾进口汽车公司做实证分析,研究结果显示厂商之间在竞争相似性认知程度差异值,以M-BENZ与AUDI于竞争相似性认知程度差异值(0.0071)为最小,显示彼此在可分配资源及市场的综合评判上,彼此认定相似性为最接近;而BMW与LEXUS差异程度值(0.2639)为最大,表示彼此认定竞争相似的差异性是最大。  相似文献   

2.
正"你真是头猪"这句经常作为朋友之间调侃的话,近些年来被越来越多的科学研究证明可能真有几分道理。科学家将猪的基因组与人的基因组进行相似性比对后发现,它们之间有极高的相似性。也就是说,人和猪确实"共享"了很多基因。生物基因组间的相似与不同构成了千姿百态的生物界,难解的DNA编码犹如天书一般,让物种的命运从出生时就被注定。在动植物界,有很多物种与人类的基因组存在相似性。这其中既有黑猩猩一类灵长目近亲,也有酵母、香蕉等与人类完全不搭界的物种。有哪些物种的基因组与人类基因组相似性较高?这种相似性产生的原因是什么?研究不同物种间的基因相似性又有什么用呢?  相似文献   

3.
针对现有的一些时间序列相似性度量函数存在的问题,在时间序列分段线性表示的基础上,提出了一种新的基于面积的度量方法。分段后的时间序列,用对齐法解决时间序列模式之间长度可能不相等的问题,再通过平移,将相交的两线段所围成的面积,作为相似性度量的函数。该方法与现有的一些相似性度量方法进行比较,并且通过人工模拟数据和真实的股票数据进行实验,证明了该方法能够更好地进行相似性搜索,并且较其他的方法,更合理,有效。  相似文献   

4.
利用随机扩增多态性DNA(RAPD)技术分析了14种仲彬草属Kengyilia植物的种间关系。对34个OPRON公司十聚体随机引物进行多态性筛选,20个(58.8%)能产生多态性。14个引物产生的112个DNA片断,用于计算种间Jaccard遗传相似性系数分析,在NTSYS程序中利用UPGMA构建系统发育树状图。分析结果表明:(1)14个Kengyilia物种存在较大的遗传多样性;(2)青藏高原的物种与新疆的物种 的RAPD变异极大;(3)形态相似、地理分布一致的物种有一定的亲缘关系,聚类在一起;(4)RAPD结果与形态学和细胞学等分析结果一致。RAPD分析方法将为Kengyilia系统分类提供DNA水平上丰富的资料。  相似文献   

5.
澳大利亚研究人员最近通过比较袋鼠和人类基因的相似性,计算出在1.5亿年前,两种生物有一个共同的哺乳动物祖先。从那时起,这个祖先在如今属于中国的土地上进化,变成不同的一些物种。所以袋鼠这种动物最早出现在中国的土地上,但它们不断迁徒,穿过了美洲大陆,抵达澳大利亚大陆和南极洲的土地。当然,那时候这些大陆还都相连,因此袋鼠可以直接跳过去。  相似文献   

6.
本文借鉴文本检索领域的研究成果,利用标注文字信息描述单个模型的语义,采用语义树表达三维模型间的语义,基于WordNet计算检索关键词与语义树中节点的语义相似性,返回语义相关性强的模型。提出较灵活的返回策略,筛选各语义相关节点的代表模型,便于用户进一步优化检索结果。实验结果表明,基于语义树的三维模型检索方法能够提高信息检索的效率,具有较高的理论及应用价值。  相似文献   

7.
提出一种基于目标分布场相似性度量的实时图形跟踪渲染算法。使用Open Flight的建模环境提供GPU实时图形渲染三维图形观察器,得到一个有二维层次的结构图,进行目标分布场设计,结合静态视点图像的运动方程,通过对图像自然分层,保留原始图像的基本信息,为了在跟踪中使分布场能适应各种复杂场景,需要对原始的分布场进行高斯平滑,通过目标分布场相似性度量,实现GPU实时图形跟踪渲染。仿真结果表明,采用该算法进行实时图形渲染,可以提高渲染跟踪效率,搜索时间短,误差率较低,提高了图形的渲染真实感。  相似文献   

8.
合理的技术创新合作预测方法是企业寻找合适的技术创新合作伙伴以提升技术创新绩效的有效手段。论文基于企业专利数据,构建专利所有权人共现网络,应用Katz指标计算企业之间的路径相似性,应用TF-IDF算法构建企业关键词向量,结合余弦相似性计算企业之间的内容相似性,应用社会网络分析方法中的中心性指标计算企业的位置相似性,将三者进一步融合得到企业之间合作的潜在可能性。通过对石墨烯领域企业专利数据分析预测企业间合作的可能性,证实该方法有效,AUC指标值为0.7242,优于单一指标相似性推荐方法,能够提升合作推荐中合适匹配的精确度。  相似文献   

9.
天地万物间的事物虽各不相同,但总有相似之处。因此人们利用这种事物之间的相似性,通过已知事物的历史和现状,来推断其他事物的“相似的未来”。选种推断,在自然领域曾经屡试不爽,但是在社会领域,虽然社会历史有时会有“惊人的相似”,但就总体而言,“未来的相似”却大打折扣,因为社会历史不会简单的重复。那么,相似性原理能否应用于社会预测?如果能够.它会有哪些局限性?这就是本文所要探讨的问题。  相似文献   

10.
[目的/意义]关键词是反映期刊研究主题、研究方法和数据源等信息的重要途径。本文尝试通过论文关键词来研究学术期刊的相似度,为期刊分类等学术研究和实际工作提供参考。[方法/过程]首先,在相关文献梳理的基础上,提出了基于论文关键词的两种期刊相似度计算方法。然后,以《中国图书馆学报》和《情报学报》为实证对象,从CSSCI采集了两种期刊1998-2017年的关键词数据。最后,计算了两种期刊的相似度,并分析了两种期刊论文的共现关键词。[结论]研究发现,两种期刊的相似度有一定波动,但整体上呈现为一个下降趋势。这反映出两种期刊上发表的论文的相似性在不断下降,而差异性在不断增加。  相似文献   

11.
Oligonucleotide microarrays are tools used to analyze samples for the presence of specific DNA sequences. In the system as presented here, specific DNA sequences are first amplified by a polymerase chain reaction (PCR) during which process they are labeled with fluorophores. The amplicons are subsequently hybridized onto an oligonucleotide microarray, which in our case is a porous nylon membrane with microscopic spots. Each spot on the membrane contains oligonucleotides with a sequence complementary to part of one specific target sequence. The solution containing the amplicons flows by external agitation many times up and down through the porous substrate, thereby reducing the time delaying effect of diffusion. By excitation of the fluorophores the emitted pattern of fluorophores can be detected by a charge-coupled device camera. The recorded pattern is a characteristic of the composition of the sample. The oligonucleotide capture probes have been deposited on the substrate by using noncontact piezo ink jet printing, which is the focus of our study. The objective of this study is to understand the mechanisms that determine the distribution of the ink jet printed capture probes inside the membrane. The membrane is a porous medium: the droplets placed on the membrane penetrate in the microstructure of it. The three-dimensional (3D) distribution of the capture probes inside the membrane determines the distribution of the hybridized fluorescent PCR products inside the membrane and thus the emission of light when exposed to the light source. As the 3D distribution of the capture probes inside the membrane eventually determines the detection efficiency, this parameter can be controlled for optimization of the sensitivity of the assay. The main issues addressed here are how are the capture probes distributed inside the membrane and how does this distribution depend on the printing parameters. We will use two model systems to study the influences of different parameters: a single nozzle print head jetting large droplets at a low frequency and a multinozzle print head emitting small droplets at a high frequency. In particular, we have investigated the effects when we change from usage of the first system to the second system. Furthermore, we will go into detail how we can obtain smaller spot sizes in order to increase the spot density without having overlapping spots, leading eventually to lower manufacturing costs of microarrays. By controlling the main print parameters influencing the 3D distribution inside the porous medium, the overall batch-to-batch variations can possibly be reduced.  相似文献   

12.
谈樨  杨旭波 《科技通报》2012,(7):130-134
自标定方法可以得到相机系统的内部参数和/或外部参数,而不对场景结构作假设或作很少假设。本文提出一种新的自标定方法,用于投影相机建模系统。一个关键点在于投影仪既可以作为主动光源使用,也可以当做一个虚拟相机使用。首先,使用结构光方法从不同角度投影并拍摄一组图像。然后,通过将空间约束关系转换为内参约束,完成对系统的自标定。最后,利用估计的参数进行3D建模。实验结果验证了本文方法的可行性。  相似文献   

13.
Microsatellite instability (MSI) characterized by alterations at simple repetitive genomic sequences is a distinct mechanism in tumorogenesis. Central nervous system (CNS) tumors have been reported to exhibit MSI, indicator of defective mismatch repair system with controversies. The present study was undertaken to examine sixteen primary brain and two spinal tumors for MSI at six mono: BAT-26, BAT-40, BAX, TGFßRII, IGFIIR and hMSH3 and four dinucleotide loci: D2S123, D9S1851, D9S283 and D18S58. Polymerase chain reaction (PCR) was done to amplify tumour and blood DNA, analyzed on 8% denaturing Polyacrylamide gel followed by autoradiography. Out of 18 CNS tumors examined, 39% exhibited MSI at BAT-26, BAT-40, D9S1851, D9S283 and D18S58 in tumoral DNA. However, no alteration was observed at BAX, TGFßRII, IGFIIR, hMSH3 and D2S123 loci. Low incidence of MS1-high hypothesizes role of MSI in evolution of CNS tumors but not in cancer initiation or progression.  相似文献   

14.
Sun YS  Peng SW  Lin KH  Cheng JY 《Biomicrofluidics》2012,6(1):014102-014102-14
In this paper, we report a new method to incorporate 3D scaffold with electrotaxis measurement in the microfluidic device. The electrotactic response of lung cancer cells in the 3D foam scaffolds which resemble the in vivo pulmonary alveoli may give more insight on cellular behaviors in vivo. The 3D scaffold consists of ordered arrays of uniform spherical pores in gelatin. We found that cell morphology in the 3D scaffold was different from that in 2D substrate. Next, we applied a direct current electric field (EF) of 338 mV/mm through the scaffold for the study of cells’ migration within. We measured the migration directedness and speed of different lung cancer cell lines, CL1-0, CL1-5, and A549, and compared with those examined in 2D gelatin-coated and bare substrates. The migration direction is the same for all conditions but there are clear differences in cell morphology, directedness, and migration speed under EF. Our results demonstrate cell migration under EF is different in 2D and 3D environments and possibly due to different cell morphology and/or substrate stiffness.  相似文献   

15.
16.

Introduction

Total 25-hydroxyvitamin D [25(OH)D] is the most reliable indicator of vitamin D status. In this study, we compared two automated immunoassay methods, the Abbott Architect 25-OH Vitamin D assay and the Roche Cobas Vitamin D total assay, with the liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Materials and methods

One hundred venous blood samples were randomly selected from routine vitamin D tests. Two of the serum aliquots were analyzed at the Abbott Architect i2000 and the Roche Cobas 6000’s module e601 in our laboratory within the same day. The other serum aliquots were analyzed at the LC-MS/MS in different laboratory. Passing-Bablok regression analysis and Bland-Altman plot were used to compare methods. Inter-rater agreement was analyzed using kappa (κ) analysis.

Results

The Roche assay showed acceptable agreement with the LC-MS/MS based on Passing-Bablok analysis (intercept: -5.23 nmol/L, 95% CI: -8.73 to 0.19; slope: 0.97, 95% CI: 0.77 to 1.15). The Abbott assay showed proportional (slope: 0.77, 95% CI: 0.67 to 0.85) and constant differences (intercept: 17.08 nmol/L; 95% CI: 12.98 to 21.39). A mean bias of 15.1% was observed for the Abbott and a mean bias of -14.1% was observed for the Roche based on the Bland-Altman plots. We found strong to nearly perfect agreement in vitamin D status between the immunoassays and LC-MS/MS. (κ: 0.83 for Abbott, κ: 0.93 for Roche) using kappa analysis.

Conclusion

Both immunoassays demonstrated acceptable performance, but the Roche Cobas assay demonstrated better performance than the Abbott Architect in the studied samples.Key words: 25-Hydroxyvitamin D, chromatography, immunoassay, methods, tandem mass spectrometry  相似文献   

17.
The unsupervised 3D model retrieval is designed to joint the information of well-labeled 2D domain and unlabeled 3D domain to learn collaborative representations. Most existing methods adopted semantic alignment, but were inevitably affected by false pseudo-label. In this paper, we design a novel Instance-Prototype Similarity Consistency Network (IPSC) to guide domain alignment with similarity consistency, which can simultaneously suppress the impact of false pseudo-label information and well reduce the domain discrepancy. IPSC contains two similarity strategies, named Single instance vs Multiple prototypes and Instance-pair vs Single prototype. The first strategy utilizes a single instance as an anchor, and measures the similarities between the anchor and multiple prototypes with the same category but from different domains. The minimization between these similarities can better align the cross-domain prototypes with Kullback–Leibler (KL) divergence than traditional Euclidean similarities. The second strategy utilizes a single prototype as an anchor, and measures the similarities between this anchor and an instance-pair with the same category but from different domains. The minimization between these similarities can conduct the instance-level alignment with KL divergence, which can better suppress the negative effect of noisy pseudo-labels. We conduct various experiments on two datasets, MI3DOR-1 (21000 2D images and 7690 3D models) and MI3DOR-2 (19694 2D images and 3982 3D models), to verify the superiority of our algorithm.  相似文献   

18.
Experimental results of cross-language information retrieval (CLIR) do not indicate why a model fails or how a model could be improved. One basic research question is thus whether it is possible to provide conditions by which one can evaluate any existing or new CLIR strategy analytically and one can improve the design of CLIR models. Inspired by the heuristics in monolingual IR, we introduce in this paper Dilution/Concentration (D/C) conditions to characterize good CLIR models based on direct intuitions under artificial settings. The conditions, derived from first principles in CLIR, generalize the idea of query structuring approach. Empirical results with state-of-the-art CLIR models show that when a condition is not satisfied, it often indicates non-optimality of the method. In general, we find that the empirical performance of a retrieval formula is tightly related to how well it satisfies the conditions. Lastly, we propose, by following the D/C conditions, several novel CLIR models based on the information-based models, which again shows that the D/C conditions are efficient to feature good CLIR models.  相似文献   

19.
Measurement of plasma hemoglobin is useful in variety of clinical conditions. In the present study we have developed a kinetic method to estimate plasma haemoglobin by using o-tolidine. This method is sensitive, rapid, economical, simple and less influenced by interfering substances. It measures plasma haemoglobin in the range of 6 to 400 mg/L (normal range < 50 mg/L) in less than two minutes and can be easily automated.  相似文献   

20.
Three different sets of primers were designed using FASTA homology search and PRIMERSELECT for the specific detection ofNeisseria gonorrhoeae using polymerase chain reaction (PCR). These primers amplified the highly conserved regions of genes for Open Reading Frame (ORF), Outer Membrane Protein (OMP) and 23S rRNA sequences ofN. gonorrhoeae. Each of the PCR primer set was evaluated using the DNA samples isolated from eight different positive isolates ofN. gonorrhoeae cultured from urethral swabs of patients visiting Maulana Azad Medical College and Safdarjung Hospital. Amplification products were analyzed on agarose gel electrophoresis. Two sets of PCR primers, designated as Ngu1/Ngu2 and Ngu5/Ngu6, specific for ORF and OMP gene respectively, amplified four regions of the gene which may help to differentiate the various strains ofN. gonorrhoeae infecting indigenous population. In contrast, a single, specific PCR product of 650 bp was visualized on agarose gel with primers Ngu3/Ngu4, amplifying the 23S rRNA gene. Under optimum conditions, as low as 25ng of DNA isolated from eight different clinical strains ofN. gonorrhoeae could be detected by PCR using Ngu3/Ngu4 set of primers. Our results suggested that Ngu3/Ngu4 could serve as good primers for the specific, reproducible and sensitive diagnosis ofNeisseria gonorrhoeae from clinical samples.  相似文献   

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