共查询到20条相似文献，搜索用时 109 毫秒
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文章从语义信息检索角度,分析了叙词表编制标准的重要性,以3个叙词表编制标准为研究对象,从词间关系分类角度对比分析了国际叙词表编制标准、中国叙词表编制标准和美国叙词表编制标准之间存在的异同,在此基础上,总结出中国叙词表编制标准存在的不足,提出了我国叙词表编制标准重新修订的建议. 相似文献
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叙词表拥有丰富的词汇及词间关系,所以重用叙词表可以极大地提高本体构建效率并降低成本.通过全面调查分析国内外叙词表转换为本体的项目和方法,对各种转换方法进行了分类研究,分别从叙词表的特征、叙词表转换本体的过程和转换成的本体的特征三个方面来分析各种转换方法的特点,在此基础上,总结了各种叙词表转换本体方法的总体特征,最后提出了应根据本体应用需求和叙词表特点两方面因素来选择叙词表转换本体方法的观点. 相似文献
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本体转化使叙词表的网络化成为可能,本文阐述了OWL语言的分类、OWL描述网络叙词表的方法及叙词表本体转化的过程和实例等,为叙词表的网络化和智能化发展提供了技术上的参考。 相似文献
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受控词表是分类表、叙词表、可检词单、同义词环、术语表、名称规范文档等的集合。由于主题词表、叙词表、分类表和网络分类法等存在多种语言和多种信息组织的方式,使检索变得尤为困难。为了提高检索效率,就需要实现叙词表和其他词表之间的互操作。文章通过对国际、美国和英国的叙词表编制标准中叙词表与其他词表互操作规则的研究,总结出叙词表编制标准中叙词表与其他受控词表互操作的发展方向,为我国叙词表编制标准关于叙词表和其他词表互操作内容的制定提供参考。 相似文献
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基于航天叙词表的领域本体半自动化构建研究 总被引：2，自引：0，他引：2
文章在基于叙词表的本体构建方法基础上,从该方法本体构建现状研究入手,针对基于叙词表向领域本体转化的一系列问题,如叙词表词间一些不确定关系表示,构建过程的OWL关系表示的细化以及叙词表转化为本体后的维护扩展等,对本体和叙词表的相关知识进行论述,并利用OWL语言来表示和描述叙词表的叙词及词间的相关关系,提出从叙词表向本体转化的理论实践方法。 相似文献
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叙词表是图书情报和信息管理领域传统的信息组织方式,而语义网的核心之一本体是一种新的信息组织方式。OWL是W3C推荐的语义网本体的描述语言标准。研究叙词表和OWL,提出了用OWL表示和描述现有的叙词表的方法,为基于叙词表来构建本体奠定了基础。 相似文献
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语义网环境下,信息用户以网络为主要获取渠道,传统叙词表亟须做出相应的改变.文章分析了基于本体模式的网络叙词表构建,提出网络叙词表的发展将大范围地发布为关联数据,实现知识组织体系与资源的自动关联,进行语义检索,网络叙词表的集成与分解有助于实现基于专题或领域的术语服务等. 相似文献
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Mehul Jariwala S. Suvarna G. Kiran Kumar Alpa Amin A. C. Udas 《Indian journal of clinical biochemistry : IJCB》2014,29(2):181-188
A study of iron, zinc, copper and selenium concentration levels was carried out in three compartments namely, maternal serum (MS), colostrums and cord blood serum (CS) of healthy Indian mothers (n = 42) who delivered healthy normal neonates without any congenital anomalies at Bhabha Atomic Research Centre hospital, Mumbai. Fe, Zn, Cu in maternal serum, cord blood and colostrums were estimated by flame atomic absorption spectrometry while Se was determined by graphite furnace absorption spectrometry. It was seen that there was a significant difference in the level of trace elements in the three compartments. The average levels of Fe in the three compartments were 1,132 ± 519, 2,312 ± 789 and 1,183 ± 602 μg/L while Zn was 514 ± 149, 819 ± 224 and 7,148 ± 2,316 μg/L respectively. Mean Cu values were 1,614 ± 295, 301 ± 77 and 392 ± 174 μg/L respectively while Se values were 70 ± 15, 36 ± 10 and 23 ± 8 μg/L respectively. The results indicated a positive correlation of Fe and Zn concentrations in MS versus CS which were (r = 0.386), (r = 0.572) respectively and Fe levels in MS and colostrums (r = 0.235). A few inter element correlations were found within compartments. Zn and Se showed a negative correlation in both MS (r = −0.489) and colostrums (r = −0.258) while a positive inter correlation of Fe and Zn was seen in MS (r = 0.44) and in CS (r = 0.54). This study gave us an overview of the serum and colostrum values of mother and neonates in Indian population, data of which are scarce. 相似文献
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The bubble-free and pulse-free fluid delivery is critical to reliable operation of microfluidic devices. In this study, we propose a new method for stable bubble-free and pulse-free fluid delivery in a microfluidic device. Gas bubbles are separated from liquid by using the density difference between liquid and gas in a closed cavity. The pulsatile flow caused by a peristaltic pump is stabilized via gas compressibility. To demonstrate the proposed method, a fluidic chamber which is composed of two needles for inlet and outlet, one needle for a pinch valve and a closed cavity is carefully designed. By manipulating the opening or closing of the pinch valve, fluids fill up the fluidic chamber or are delivered into a microfluidic device through the fluidic chamber in a bubble-free and pulse-free manner. The performance of the proposed method in bubble-free and pulse-free fluid delivery is quantitatively evaluated. The proposed method is then applied to monitor the temporal variations of fluidic flows of rat blood circulating within a complex fluidic network including a rat, a pinch valve, a reservoir, a peristaltic pump, and the microfluidic device. In addition, the deformability of red blood cells and platelet aggregation are quantitatively evaluated from the information on the temporal variations of blood flows in the microfluidic device. These experimental demonstrations confirm that the proposed method is a promising tool for stable, bubble-free, and pulse-free supply of fluids, including whole blood, into a microfluidic device. Furthermore, the proposed method will be used to quantify the biophysical properties of blood circulating within an extracorporeal bypass loop of animal models. 相似文献
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The current epidemic affecting Indians is coronary artery disease (CAD), and is currently one of the most common causes of mortality and morbidity in developed and developing countries. The higher rate of CAD in Indians, as compared to people of other ethnic origin, may indicate a possible genetic susceptibility. Hence, Lp(a), an independent genetic risk marker for atherosclerosis and cardiovascular disease assumes great importance. Lp(a), an atherogenic lipoprotein, contains a cholesterol rich LDL particle, one molecule of apolipoprotein B-100 and a unique protein, apolipoprotein (a) which distinguishes it from LDL. Apo(a) is highly polymorphic and an inverse relationship between Lp(a) concentration and apo(a) isoform size has been observed. This is genetically controlled suggesting a functional diversity among the apo(a) isoforms. The LPA gene codes for apo(a) whose genetic heterogeneity is due to variations in its number of kringles. The exact pathogenic mechanism of Lp(a) is still not completely elucidated, but the structural homology of Lp(a) with LDL and plasmin is possibly responsible for its acting as a link between atherosclerosis and thrombosis. Upper limits of normal Lp(a) levels have not been defined for the Indian population. A cut off limit of 20 mg/dL has been suggested while for the Caucasian population it is 30 mg/dL. Though a variety of assays are available for its measurement, standardization of the analytical method is highly complicated as a majority of the methods are affected by the heterogeneity in apo(a) size. No therapeutic drug selectively targets Lp(a) but recently, new modifiers of apo(a) synthesis are being considered. 相似文献
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公司社会绩效影响财务绩效的实证研究——来自中国上市公司的经验证据 总被引：6，自引：0，他引：6
公司社会绩效与财务绩效的关系是现代公司社会责任研究中的一个基本问题.在综合比较各种社会绩效计量方法的基础上,采用行为评估问卷调查方法来测度我国上市公司的社会绩效水平,以期有较佳的信度和效度.实证研究表明:当前我国上市公司总体社会绩效水平不高,还有待进一步提升;公司社会绩效与公司财务绩效显著正相关;公司社会绩效各个子维度的绩效水平与公司财务绩效的相关性存在差异.这一结论对于建立与公司社会责任相适应的公司治理机制和竞争战略,从而促使公司积极承担社会责任具有一定的现实意义. 相似文献
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Jon-Arild JohannessenAuthor Vitae Bjørn OlsenAuthor Vitae 《International Journal of Information Management》2011,31(1):30-37
Although often downplayed and instrumental, there is evidence that communication in projects is essential in achieving value creation. Our main interest in this paper is on temporary continuity, a situation where the temporary becomes a permanent condition in social systems. The question that we have address is: What characterizes project communication in a situation with temporary continuity?We argue for the need to transform communication processes into communication capabilities. In a situation with temporary continuity, there is a need to connect to a large number of value-creating processes, and communicating capabilities need to be a part of a communication system, where the aim is to bind together value-creating processes and communication capabilities. We construct a viable system consisting of five sub-systems. To become a viable system, projects in the form of temporary continuity, must handle the potential conflict between a culture of performance and a culture of innovation. This involves developing social mechanisms for coordination and interaction, with a focus on developing communication capabilities, in parallel with focusing on all of the five value-creation processes. 相似文献
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《Journal of The Franklin Institute》2022,359(11):5251-5271
In this paper, a distributed adaptive optimization-based formation tracking strategy with double parameter projections for multi-agent systems is addressed under a centralized task allocation and distributed task execution (CTA-DTE) framework. Since a pre-described formation strategy is unable to adapt to a complex and dynamic environment, an optimization-based approach is proposed to transfer the formation tracking problem into a time-varying optimization one, subject to some constraints with several time-varying parameters which determine the rule of formation configuration change adaptively. These parameters are computed by a centralized unit and allocated to each agent as a global mission. Furthermore, each agent cooperates with others to execute this mission under a distributed optimization-based strategy, which combines a geometric center observer technology and a novel double parameter projections technology. The former ensures accurate tracking of a continuous reference trajectory. The latter guarantees that all agents enter into a time-varying security region and never escape from it, and meanwhile, all agents are attracted towards the best time-varying formation configuration via a gradient descent with a compensation. Finally, some simulation results are illustrated to verify the effectiveness of the strategy. 相似文献
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《International Journal of Information Management》2017,37(6):611-621
As CAD models continue to become more critical information sources in the product’s lifecycle, it is necessary to develop efficient mechanisms to store, retrieve, and manage larger volumes of increasingly complex data. Because of their unique characteristics, 3D annotations can be used to embed design and manufacturing information directly into a CAD model, which makes models effective vehicles to describe aspects of the geometry or provide additional information that can be connected to a particular geometric element. However, access to this information is often limited, difficult, and even unavailable to external applications. As model complexity and volume of information continue to increase, new and more powerful methods to interrogate these annotations are needed.In this paper, we demonstrate how 3D annotations can be effectively structured and integrated into a Product Lifecycle Management (PLM) system to provide a cohesive view of product-related information in a design environment. We present a strategy to organize and manage annotation information which is stored internally in a CAD model, and make it fully available through the PLM. Our method involves a dual representation of 3D annotations with enhanced data structures that provides shared and easy access to the information. We describe the architecture of a system which includes a software component for the CAD environment and a module that integrates with the PLM server. We validate our approach through a software prototype that uses a parametric modeling application and two commercial PLM packages with distinct data models. 相似文献
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《Journal of The Franklin Institute》2023,360(9):5969-5995
When the Preisach operator, a commonly used hysteresis model, is coupled with uncertain unparametrizable nonlinear dynamics of systems, its tracking control problem in particular with the demands for prescribed tracking accuracy and finite convergence time is challenging, and has not yet been solved in the existing literature. In this study, we focus on the problem, and develop a fixed-time adaptive fuzzy control scheme as a solution to it, based upon a novel decomposition of the Preisach model, the design of a robust control framework, and the integration of a direct adaptive fuzzy control approach. With our scheme, it can be rigorously proved that the tracking error goes to a predefined interval around zero in a bounded convergence time, and all signals in the closed-loop system are bounded. Besides theoretical analysis, the obtained results are also confirmed by experimental tests based on a real-life piezoactuated positioner. 相似文献