共查询到20条相似文献，搜索用时 125 毫秒
1.
讨论了全数字接收机中同步算法的设计与实现,给出了基于Ｇａｒｄｎｅｒ反馈环路的定时 同步算法和基于数字Ｃｏｓｔａｓ环的载波相位补偿算法的定点实现方案,并在Ａｌｔｅｒａ公司的ＤＳＰ Ｂｕｉｌｄｅｒ上实现了该算法．计算机仿真和ＦＰＧＡ（ＦｉｅｌｄＰｒｏｇｒａｍｍａｂｌｅＧａｔｅＡｒｒａｙ）实现都验证了其有 效性,测试结果表明,该系统信噪比恶化小于１５ｄＢ,时钟捕捉带大于±１％,载波频差捕捉带 大于±４％． 相似文献
2.
在不确定环境中确保地产质量估计性能的扰动上界王卫平（中国科技大学２３００２６）ＰｅｒｔｕｒｂａｔｉｎｓＵｐｐｅｒＢｏｕｎｄｏｆＧｕａｒａｎｔｅｅｄＥｓｔｉｍａｔｉｏｎＰｅｒｆｏｒｍａｎｃｅｆｏｒＲｅａｌＥｓｔａｔｅＱｕａｌｉｔｙｉｎＵｎｃｅｒｔａｉｎ... 相似文献
3.
Shiquan Wu 《中国科学院研究生院学报》1994,(1)
ＥＮＵＭＥＲＡＴＩＯＮＳＯＦＳＥＭＩＯＲＤＥＲＳ￥ＳｈｉｑｕａｎＷｕ（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ，ＡｃａｄｅｍｉａＳｉｎｉｃａＰ．Ｏ．Ｂｏｘ２７３４，Ｂｅｉｊｉｎｇ１０００８０）Ａｂｓｔｒａｃｔ：ｉｎｔｈｉｓｐａｐｅｒ... 相似文献
4.
为了提高人脸检测的速度及鲁棒性,提出了一种基于级联分类器和期望最大、主成分分析（ＥＭ ＰＣＡ）的人脸检测方法．该方法在训练阶段利用不同分辨率的训练样本来训练２个ｆｉｓｈｅｒ线性分类器,再利用ＥＭ ＰＣＡ提取特征来训练非线性支持向量机（ＳＶＭ）;在检测阶段,首先通过２个ｆｉｓｈｅｒ线性分类器快速过滤掉大量的背景区域,再利用非线性支持向量机对余下的候选区域进行进一步验证,以确认是否为人脸．实验结果证明了该方法的有效性和正确性． 相似文献
5.
在不确定投资环境中的地产质量估计王卫平，奚宏生（中国科技大学２３００２６）ＥｓｔｉｍａｔｉｏｎｆｏｒＲｅａｌＥｓｔａｔｅＱｕａｌｉｔｙｉｎＵｎｃｅｒｔａｉｎｉｎｖｅｓｔｍｅｎｔＣｉｒｃｕｍｓｔａｎｃｅｓ￥ＷａｎｇＷｅｉｐｓｎｇ＆ＸｉＨｏｎｇｓｈｅｎｇ... 相似文献
6.
Liang Hua 《中国科学院研究生院学报》1994,(2)
ＡＳＹＭＰＴＯＴＩＣＥＦＦＩＣＩＥＮＣＹＩＮＡＰＡＲＴＬＹＬＩＮＥＡＲＲＥＧＲＥＳＳＩＯＮＭＯＤＥＬＬｉａｎｇＨｕａ（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｂｅｉｊｉｎｇ１０００８０，Ｐ．Ｒ．Ｃｈｉｎａ）Ａ... 相似文献
7.
经济系统测不准性和预测王刊良，徐寅峰（西安交通大学管理学院）ＵｎｃｅｒｔａｉｎｔｙａｎｄｆｏｒｅｃａｓｔｉｎｇｉｎＥｃｏｎｏｍｉｃＳｙｓｔｅｍＷａｎｇＫａｎｌｉａｎｇ＆ＸｕＹｉｎｆｅｎｇＥｃｏｎｏｍｉｃｓｙｓｔｅｍｉｓａｖｅｒｙｃｏｍｐｌｅｘｓｙｓｔ... 相似文献
8.
短裙竹荪多糖清除O^—.2及对人工细胞膜自由基氧化的影响 总被引：3，自引：0，他引：3
短裙竹荪「Ｄｉｃｔｙｏｐｈｏｒａ ｄｕｐｌｉｃａｔａ（Ｂｏｓｅ）Ｆｉｓｈｅｒ」经热水抽提,乙醇沉淀,Ｓｅｖａｇ法去蛋白,乙醇分级分离,再经ＤＥＡＥ－纤维素柱层析得多糖组分ＰＳ。在体外产生Ｏ＾－．２的反应体系中,竹荪多糖组分ＰＳ在较低浓度下（〈２００ｍｇ／Ｌ）具有清除Ｏ＾－．２的作用,而在较高浓度下（〉２００ｍｇ／Ｌ）作用不明显。同时用荧光法研究了竹荪多糖组分ＰＳ对人红细胞膜脂质过氧化的影响,结果表 相似文献
9.
采用分子束外延技术（ＭＢＥ）生长了具有ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层的单量子阱和多量子阱材料．采用ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层掩埋衬底缺陷，获得的量子阱结构材料被成功地用于制作量子阱激光器．波长为７７８ｎｍ的激光器，最低阈值电流为３０ｍＡ，室温下线性光功率大于２０ｍＷ． 相似文献
10.
《中国科学院研究生院学报》1999,(2)
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ ＡｇｒａｐｈＧｉｓａｎｏｒｄｅｒｅｄｐａｉｒｏｆｄｉｓｊｏｉｎｔｓｅｔｓ（Ｖ,Ｅ）ｓｕｃｈｔｈａｔＥｉｓａｓｕｂｓｅｔｏｆｔｈｅｓｅｔｏｆｕｎｏｒｄｅｒｅｄｐａｉｒｓｏｆＶ,ｗｈｅｒｅｔｈｅｓｅｔｓＶａｎｄＥａｒｅｆｉｎｉｔｅ．ＴｈｅｓｅｔＶｉｓｃａｌｌｅｄｔｈｅｓｅｔｏｆｖｅｒｔｉｃｅｓａｎｄＥｉｓｃａｌｌｅｄｔｈｅｓｅｔｏｆｅｄｇｅｓ．ＴｈｅｙａｒｅｕｓｕａｌｌｙｄｅｎｏｔｅｄｂｙＶ（Ｇ）ａｎｄＥ（Ｇ）,ｒｅｓｐｅｃｔｉｖｅｌｙ．Ａｎｅｄｇｅ｛ｘ,ｙ｝ｉｓｓａ… 相似文献
11.
本文在加权平方损失下导出了平衡的双向分类随机效应模型中方差分量的Bayes估计,并利用 非参数方法构造了方差分量的经验Bayes (EB)估计。在适当的条件下证明 了EB估计的收敛速度。最后,给出一个满足主要结果的例子。 相似文献
12.
13.
Adriano Veloso Anderson A. FerreiraMarcos André Gonçalves Alberto H.F. LaenderWagner Meira Jr. 《Information processing & management》2012
Authorship disambiguation is an urgent issue that affects the quality of digital library services and for which supervised solutions have been proposed, delivering state-of-the-art effectiveness. However, particular challenges such as the prohibitive cost of labeling vast amounts of examples (there are many ambiguous authors), the huge hypothesis space (there are several features and authors from which many different disambiguation functions may be derived), and the skewed author popularity distribution (few authors are very prolific, while most appear in only few citations), may prevent the full potential of such techniques. In this article, we introduce an associative author name disambiguation approach that identifies authorship by extracting, from training examples, rules associating citation features (e.g., coauthor names, work title, publication venue) to specific authors. As our main contribution we propose three associative author name disambiguators: (1) EAND (Eager Associative Name Disambiguation), our basic method that explores association rules for name disambiguation; (2) LAND (Lazy Associative Name Disambiguation), that extracts rules on a demand-driven basis at disambiguation time, reducing the hypothesis space by focusing on examples that are most suitable for the task; and (3) SLAND (Self-Training LAND), that extends LAND with self-training capabilities, thus drastically reducing the amount of examples required for building effective disambiguation functions, besides being able to detect novel/unseen authors in the test set. Experiments demonstrate that all our disambigutators are effective and that, in particular, SLAND is able to outperform state-of-the-art supervised disambiguators, providing gains that range from 12% to more than 400%, being extremely effective and practical. 相似文献
14.
在全球经济一体化的时代背景下，电子商务在我们的经济生活中发挥出越来越重要的作用。根据我国电子商务的发展状况，指出了制约其发展的8个因素，深入分析现阶段我国电子商务以及电子政务赖以生存的环境问题，进而从7个方面提出了解决问题的措施和对策，以达到加快我国电子商务健康发展的步伐。 相似文献
15.
心理学实验对象的特殊性决定了心理学研究对实验室环境、仪器性能及实验控制的特殊要求。本文以心理学规律为指导,以控制心理学无关变量并创设理想的实验条件为目的,从实验室内外部环境与专业实验室功能上出发,探讨心理学科研实验室的建设。 相似文献
16.
This paper reports a two-layered polydimethylsiloxane microfluidic device—Flip channel, capable of forming uniform-sized embryoid bodies (EBs) and performing stem cell differentiation within the same device after flipping the microfluidic channel. The size of EBs can be well controlled by designing the device geometries, and EBs with multiple sizes can be formed within a single device to study EB size-dependent stem cell differentiation. During operation of the device, cells are positioned in the designed positions. As a result, observation and monitoring specific population of cells can be achieved for further analysis. In addition, after flipping the microfluidic channel, stem cell differentiation from the EBs can be performed on an unconfined flat surface that is desired for various differentiation processes. In the experiments, murine embryonic stem cells (ES-D3) are cultured and formed EBs inside the developed device. The size of EBs is well controlled inside the device, and the neural differentiation is performed on the formed EBs after flipping the channel. The EB size-dependent stem cell differentiation is studied using the device to demonstrate its functions. The device provides a useful tool to study stem cell differentiation without complicated device fabrication and tedious cell handling under better-controlled microenvironments. 相似文献
17.
Embryoid body (EB) formation forms an important step in embryonic stem cell differentiation invivo. In murine embryonic stem cell (mESC) cultures EB formation is inhibited by the inclusion of leukaemic inhibitory factor (LIF) in the medium. Assembly of mESCs into aggregates by positive dielectrophoresis (DEP) in high field regions between interdigitated oppositely castellated electrodes was found to initiate EB formation. Embryoid body formation in aggregates formed with DEP occurred at a more rapid rate-in fact faster compared to conventional methods-in medium without LIF. However, EB formation also occurred in medium in which LIF was present when the cells were aggregated with DEP. The optimum characteristic size for the electrodes for EB formation with DEP was found to be 75-100 microns; aggregates smaller than this tended to merge, whilst aggregates larger than this tended to split to form multiple EBs. Experiments with ESCs in which green fluorescent protein (GFP) production was targeted to the mesodermal gene brachyury indicated that differentiation within embryoid bodies of this size may preferentially occur along the mesoderm lineage. As hematopoietic lineages during normal development derive from mesoderm, the finding points to a possible application of DEP formed EBs in the production of blood-based products from ESCs. 相似文献
18.
《Journal of The Franklin Institute》2022,359(11):5559-5574
Based on a recent generalised version of the Mikhailov stability criterion, this paper presents a Kharitonov–like test for a class of linear fractional–order systems described by transfer functions whose coefficients are subject to interval uncertainties. To this purpose, first the transfer function is associated with an integer-order complex polynomial function of the generalised frequency (i.e. the current coordinate along the boundary radii of the instability sector) whose coefficients are uncertain. Then the geometrical form of the value set of this characteristic polynomial is determined from the direct examination of its monomial terms. To show how the test operates, it is finally applied to two fractional–order transfer functions whose coefficients belong to given intervals. 相似文献
19.
Embryonic stem cells (ESCs) are pluripotent with multilineage potential to differentiate into virtually all cell types in the organism and thus hold a great promise for cell therapy and regenerative medicine. In vitro differentiation of ESCs starts with a phase known as embryoid body (EB) formation. EB mimics the early stages of embryogenesis and plays an essential role in ESC differentiation in vitro. EB uniformity and size are critical parameters that directly influence the phenotype expression of ESCs. Various methods have been developed to form EBs, which involve natural aggregation of cells. However, challenges persist to form EBs with controlled size, shape, and uniformity in a reproducible manner. The current hanging-drop methods are labor intensive and time consuming. In this study, we report an approach to form controllable, uniform-sized EBs by integrating bioprinting technologies with the existing hanging-drop method. The approach presented here is simple, robust, and rapid. We present significantly enhanced EB size uniformity compared to the conventional manual hanging-drop method. 相似文献
20.
The problem of designing optimal process-specific rules for non-parametric tuning is undertaken in the paper. It is shown that producing non-parametric process-specific optimal tuning rules for PID controllers leads to the problem that can be characterized as optimization under uncertainty. This happens due to the fact that tuning rules, unlike tuning constants, are produced not for a particular process or plant model but for a set of models from a certain domain. The novelty of the proposed approach is that the problem of obtaining optimal tuning rules for a flow process is formulated and solved as a problem of optimization of an integral performance criterion parametrized through values that define the domain of available process models. The considered non-parametric tuning assumes the use of the modified relay feedback test (MRFT) recently proposed in the literature. It allows one to tune the PID controller satisfying the requirements to gain or phase margins that is achieved through coordinated selection of tuning rules and test parameters. This approach constitutes a holistic approach to tuning. In the present paper, optimal tuning rules coupled with MRFT, for flow loops, are proposed. Final results are presented in the form of tables containing coefficients of optimal tuning rules for the PI controller, obtained for a number of specified gain margins. The produced non-parametric tuning rules well agree with the practice of loop tuning. 相似文献