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41.
姚国任 《吉林化工学院学报》2021,38(9):53-59
文章通过Python爬虫技术对中国铁路12306网站进行信息抓取并以数据流分析的方法生成有效的电子客票,为出行者提供最佳行程方案。12306网站开启自动提醒这一功能,通过多渠道将订阅的信息推送至客户,方便了出行迁徙的人,但缺点是刷新频率固化,碎片余票严重。一种基于Python爬虫技术的设计系统提出了很好的解决方案。该系统架构主要包括:调用12306官网的查询接口;采集并解析往返车次、站点码表等信息;以拼接技术手段处理数据流,突破固有频率实时查询余票信息;借助于第三方的信息推送工具Server酱发出实时信息。实验结果表明系统的优化算法能最大限度的将碎片余票集成应用,方案行之有效。 相似文献
42.
众所周知,抗噪问题是现在语音识别研究中的重点。文章描述了一种新的抗噪语音识别方法,即通过改进型重复Wiener滤波结合后验概率联合模型PUM(PosteriorUnionModel)[3]实现在噪声环境下连续字语音识别的方法。这种方法先采用改进型重复Wiener滤波器对语音信号进行语音增强预处理,消除已知噪声,为PUM模型提供只有局部频带被噪声污染的语音信号,再利用PUM模型进行抗噪语音识别。试验表明在各种不同的噪声环境下新方法有更高的平均识别率。 相似文献
43.
你是否想过要在一个Palm设备上阅读或更新文档和电子表格?那么就安装来自Data Viz的Documents To GoProfessional Edition 3.0(市场价50美元)吧。在每次HotSync过程中,下载的文件将会与桌面系统进行同步,这样不管是在桌面系统还是在Palm设备上进行的编辑,都会反映到另一个文件拷贝上。Documents To Go的前一个版本只提供 相似文献
44.
Although experiments in rodents and human population-based studies have demonstrated the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac in colorectal cancer (CRC) prevention, a detailed knowledge of the underlying mechanism of action of this drug is limited. To better understand the chemopreventitive effects of sulindac, especially early sulindac-induced apoptotic events, we used the CRC cell line LIM1215 as an experimental model, focusing on proteins secreted into the LIM1215 culture medium - i.e., the secretome. This subproteome comprises both soluble-secreted proteins and exosomes (30-100?nm diameter membrane vesicles released by several cell types). Selected secretome proteins whose expression levels were dysregulated by 1?mM sulindac treatment over 16?h were analyzed using 2-D DIGE, cytokine array, Western blotting, and MS. Overall, 150 secreted proteins were identified, many of which are implicated in molecular and cellular functions such as cell proliferation, differentiation, adhesion, invasion, angiogenesis, metastasis, and apoptosis. Our secretome-based proteomic studies have identified several secreted modulators of sulindac-induced apoptosis action (e.g., Mac-2 binding protein, Alix, 14-3-3 isoforms, profilin-1, calumenin/Cab45 precursors, and the angiogenic/tumor growth factors interleukin 8 (IL-8) and growth related oncogene (GRO-α)) that are likely to improve our understanding of the chemopreventitive action of this NSAID in CRC. 相似文献
45.
Compassisonekindofclassicalheadinginstrument,comparedtootherheadingsystems,issmallerinsize,lighterinweight,quickerinreacationandmorereliableandsoon,especialywhenotherde-vicesarebrokendown,itbecametheonlyoneheadingdevice,soitisveryimportantinships.Butbecauseithaslowprecision,itonlyactsasoneauxiliaryheadingdevice.Ontheotherhand,compasshasdeviationthatcanchangewithtimepassing,soithastobecor-rectedtimeandtimesothatitcansatisfytherequest.Andatthesametime,thecorrectionofdeviationisrealizedbyhand,whi… 相似文献
46.
In this paper, an intranet portal is considered as an information infrastructure (organizational memory information system, OMIS) supporting organizational learning. The properties and the hierarchical structure of information and knowledge in an intranet portal OMIS was identified as a problem for navigation tools of an intranet portal interface. The problem relates to navigation and retrieval functions of intranet portal OMIS and is expected to adversely affect user performance, satisfaction, and usefulness. To solve the problem, a conceptual model for navigation tools of an intranet portal interface was proposed and an experiment using a crossover design was conducted with 10 participants. In the experiment, a separate access method (tabbed tree tool) was compared to an unified access method (single tree tool). The results indicate that each information/knowledge repository for which a user has a different structural knowledge should be handled separately with a separate access to increase user satisfaction and the usefulness of the OMIS and to improve user performance in navigation. 相似文献
47.
Wang P Ji Q Wayman JL 《IEEE transactions on pattern analysis and machine intelligence》2007,29(4):665-670
This paper presents methods of modeling and predicting face recognition (FR) system performance based on analysis of similarity scores. We define the performance of an FR system as its recognition accuracy, and consider the intrinsic and extrinsic factors affecting its performance. The intrinsic factors of an FR system include the gallery images, the FR algorithm, and the tuning parameters. The extrinsic factors include mainly query image conditions. For performance modeling, we propose the concept of "perfect recognition", based on which a performance metric is extracted from perfect recognition similarity scores (PRSS) to relate the performance of an FR system to its intrinsic factors. The PRSS performance metric allows tuning FR algorithm parameters offline for near optimal performance. In addition, the performance metric extracted from query images is used to adjust face alignment parameters online for improved performance. For online prediction of the performance of an FR system on query images, features are extracted from the actual recognition similarity scores and their corresponding PRSS. Using such features, we can predict online if an individual query image can be correctly matched by the FR system, based on which we can reduce the incorrect match rates. Experimental results demonstrate that the performance of an FR system can be significantly improved using the presented methods 相似文献
48.
Active and dynamic information fusion for facial expression understanding from image sequences 总被引:6,自引:0,他引:6
This paper explores the use of multisensory information fusion technique with dynamic Bayesian networks (DBN) for modeling and understanding the temporal behaviors of facial expressions in image sequences. Our facial feature detection and tracking based on active IR illumination provides reliable visual information under variable lighting and head motion. Our approach to facial expression recognition lies in the proposed dynamic and probabilistic framework based on combining DBN with Ekman's facial action coding system (FACS) for systematically modeling the dynamic and stochastic behaviors of spontaneous facial expressions. The framework not only provides a coherent and unified hierarchical probabilistic framework to represent spatial and temporal information related to facial expressions, but also allows us to actively select the most informative visual cues from the available information sources to minimize the ambiguity in recognition. The recognition of facial expressions is accomplished by fusing not only from the current visual observations, but also from the previous visual evidences. Consequently, the recognition becomes more robust and accurate through explicitly modeling temporal behavior of facial expression. In this paper, we present the theoretical foundation underlying the proposed probabilistic and dynamic framework for facial expression modeling and understanding. Experimental results demonstrate that our approach can accurately and robustly recognize spontaneous facial expressions from an image sequence under different conditions. 相似文献
49.
This paper presents a novel scheme for visual servoing of a nonholonomic mobile robot equipped with a monocular camera
in consideration of field-of-view (FOV) constraints. In order to loosen the FOV constraints, the system states are expressed by the
homography between the current frame and the key frame so that the target is not necessarily to be always visible in the control
process. A switched visual controller is designed to deal with the nonholonomic constraints. Moreover, an iteration strategy is
used to eliminate errors caused by the parameter uncertainty. The stablity and robustness of the proposed scheme are guaranteed
by theoretical analysis. Compared to conventional schemes, the proposed approach has the following advantages: 1) a better path
in Cartesian space can be achieved owing to the loosening of FOV constraints; 2) the iteration strategy ensures the robustness
to parameter uncertainty; 3) when used in landmark-based navigation, it needs much sparser and simpler landmarks than those
localization-based approaches need. Simulation results demonstrate the effectiveness of the proposed method. 相似文献
50.
In the last two decades, the damage detection for civil engineering structures has been widely treated as a modal analysis problem and most of the currently available vibration-based system identification approaches are based on modal parameters, namely the natural frequencies, mode shapes and damping ratios, and/or their derivations, which are suitable for linear systems. Nonlinearity is generic in engineering structures. For example, the initiation and development of cracks in civil engineering structures as typical structural damages are nonlinear process. One of the major challenges in damage detection, early warning and damage prognosis is to obtain reasonably accurate identification of nonlinear performance such as hysteresis which is the direct indicator of damage initiation and development under dynamic excitations. In this study, a general data-based identification approach for hysteretic performance in form of nonlinear restoring force using structural dynamic responses and complete and incomplete excitation measurement time series was proposed and validated with a 4-story frame structure equipped with smart devices of magneto-rheological (MR) damper to simulate nonlinear performance. Firstly, as an optimization method, the least-squares technique was employed to identify the system matrices of an equivalent linear system of the nonlinear structure model basing on the excitation force and the corresponding vibration measurements with impact test when complete and incomplete excitations; and secondly, the nonlinear restoring force of the structure was identified and compared with the test measurements finally. Results show that the proposed data-based approach is capable of identifying the nonlinear behavior of engineering structures and can be employed to evaluate the damage initiation and development of different structure under dynamic loads. 相似文献