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1.
Conglomerates as a general framework for informetric research   总被引:2,自引:0,他引:2  
We introduce conglomerates as a general framework for informetric (and other) research. A conglomerate consists of two collections: a finite source collection and a pool, and two mappings: a source-item map and a magnitude map. The ratio of the sum of all magnitudes of item-sets, and the number of elements in the source collection is called the conglomerate ratio. It is a kind of average, generalizing the notion of an impact factor. The source-item relation of a conglomerate leads to a list of sources ranked according to the magnitude of their corresponding item-sets. This list, called a Zipf list, is the basic ingredient for all considerations related to power laws and Lotkaian or Zipfian informetrics. Examples where this framework applies are: impact factors, including web impact factors, Bradford–Lotka type bibliographies, first-citation studies, word use, diffusion factors, elections and even bestsellers lists.  相似文献   

2.
为预测气候变化下的森林植被生长季特征变化,本文基于华北晋冀山地区和黄土高原区两个区域44个气象站1961-2013年日气温数据,分析了华北湿润半湿润地区两个区域树木生长季特征的变化趋势。定义生长季开始时间为当连续5天日平均温度≥5℃,选第5天作为生长季开始时间;生长季结束时间为当秋季连续5天日平均温度<5℃,选第5天作为生长季结束时间。结果表明:①1961-2013年晋冀山地区和黄土高原区以及两个区域整体树木生长季开始时间呈现显著提前趋势,变化速率分别为-1.7d/10a、-2.1d/10a和-1.9d/10a;树木生长季结束时间均呈现显著延后趋势(p<0.05),变化速率分别为0.9d/10a、1.1d/10a和1.0d/10a;研究区树木生长季长度表现出明显的延长趋势,晋冀山地区和黄土高原区以及两个区域整体的树木生长季长度时间变化速率分别为2.6d/10a、3.2d/10a和2.9d/10a,树木生长季长度分别延长13.3d、16.4d和14.8d;②1961-2013年,海拔对树木生长季指标的影响,除了对晋冀山地区的树木生长季开始影响不大以外,对于两个研究区的其他树木生长季指标均有显著影响;研究区树木生长季指标(生长季开始时间,结束时间和生长季长度)与春季和秋季气温都显著相关;③1961-2013年,树木生长季开始时间变化趋势在整个研究区空间上大部分呈提前趋势,树木生长季结束时间大部分呈延后趋势和树木生长季长度的变化趋势在空间上则大部分呈延长趋势。  相似文献   

3.
爱就是教育     
吴全民 《科教文汇》2013,(15):27-27
教师必须加强自身修养,培养师爱的观念,因为爱是一种意识,是一种信任,是一种良心,是一种积累,是一种力量。爱就是一种教育,每一个教师要把对学生的热爱、尊重、理解和期待,融合在整个教学过程中,实现人民教师爱岗敬业、教书育人的价值。  相似文献   

4.
付超  刘华景 《科教文汇》2011,(26):21-22,59
幸福是一种主观的体验,是人们获得最大心理满足和人生意义的一种状况。幸福不仅仅是一种主观体验,还是一种存在(或客观存在)。幸福的感受是对幸福的存在的感受。幸福悖论是一种人的主观和客观之间的一种自相矛盾,是义与利之间的一种失衡状态,是过程与结果的相异性。因此在我们的人生实践的过程中,我们要寻找幸福的社会和个人的守恒路径。  相似文献   

5.
1961年~2004年东北地区四季降水的时空演变特征   总被引:7,自引:1,他引:6  
利用Anusplin插值软件对东北地区146站1961年~2004年四季降水量进行空间化处理,各季区域平均MRE分别为春季14.3%、夏季14.1%;秋季18.1%;冬季25.1%。对栅格数据采用空间分析和时间序列分析相结合的方法进行四季降水时空演变特征分析,结果表明:从时间上看,春季,整个时段呈弱增多趋势,但不显著,1980年代前增加,之后减少;夏季呈减少趋势,1985以后呈显著减少趋势;秋季整个时段呈弱的减少趋势,1990年代开始显著减少,2000年以后略有增加;冬季年代际变化特征明显,呈波动增多趋势,近10年增幅较大。从空间分布上看,春季,黑龙江北部和东部部分地区、吉林东部降水显著增多,增幅为(3~9)mm/10年,辽宁中部部分地区降水显著减少,减幅为(3~7)mm/10年。夏季,东北大部地区降水以减少为主,黑龙江中部和辽东半岛地区显著减少,减幅为(20~40)mm/10年。秋季,东北大部地区降水减少,黑龙江东部局部、吉林中部和南部部分地区显著减少,减幅为(6~10)mm/10年。冬季,黑龙江大部、吉林大部降水显著增多,增幅为(1~3)mm/10年,辽宁南部和西部部分地区显著减少,减幅为(1~2)mm/10年。  相似文献   

6.
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   

7.
Circulating the truth and quarantining a subset of rumor spreaders are two major rumor-quelling strategies. In practice, a mixture of the two strategies may be more effective than any one of the two strategies. This paper focuses on effectiveness analysis of the mixed strategy. For this purpose, we are going to establish a rumor-truth competing model on two-layer network. First, we introduce a Markov model characterizing the stochastic dynamics of the rumor-truth competing process, and write the corresponding Kolmogorov model capturing the expected dynamics of the rumor-truth competing process. Second, we give a bilinear model as the first approximation to the Kolmogorov model, and suggest a generic model as a more accurate approximation to the Kolmogorov model. The two models are the focus of concern in this work. For ease in treatment, we describe a limit system of the generic model. By studying the limit model, we present a criterion for the rumor to subside, a criterion for the rumor not necessarily to subside, and a criterion for the rumor to persist, respectively. These findings are instructive to the quelling of false rumors. Finally, through computer experiments we find that when a rumor subsides, the bilinear model is a good approximation to the Kolmogorov model.  相似文献   

8.
This paper develops a cooperative federated reinforcement learning (RL) strategy that enables two unmanned aerial vehicles (UAVs) to cooperate in learning and predicting the movements of an intelligent deceptive target in a given search area. The proposed strategy allows the UAVs to autonomously cooperate, through information exchange of the gained experience to maximize the target detection performance and accelerate the learning speed while maintaining privacy. Specifically, we consider a monitoring model that includes a search area, a charging station, two cooperative UAVs, an intelligent deceptive uncertain moving target, and a fake (false) target. Each UAV is equipped with a limited-capacity rechargeable battery and a communication unit for exchanging the gained experience. The problem of maximizing the detection probability of the uncertain deceptive target using cooperative UAVs is mathematically modeled as a search-benefit maximization problem, which is then reformulated as a Markov decision process (MDP) due to the uncertainty nature of the problem. Because there is no prior information on the targets’ movement, a cooperative RL, is utilized to tackle the problem. The proposed cooperative RL-based algorithm is a distributed collaborative mechanism that enables the two UAVs, i.e., agents, to individually interact with the operating environment and maximize their cumulative rewards by converging to a shared policy while achieving privacy. Simulation results indicate that a cooperative RL-based dual UAV system can noticeably improve the target detection probability, reduce the detection performance, and accelerate the learning speed.  相似文献   

9.
基于低碳化视角的东北地区振兴——以吉林市为例   总被引:2,自引:0,他引:2  
《东北地区振兴规划》提出要将东北地区建设成为综合经济发展水平较高的重要经济增长区域。论文以东北地区振兴为背景,探讨吉林市产业低碳化发展的路径,提出吉林市实现低碳发展的政策与建议。吉林市作为东北老工业基地之一和工业重镇,已形成了以石化、汽车、冶金、电力为龙头的产业格局。实现吉林市产业升级和现代化改造,低碳化发展是必然趋势。吉林市低碳经济发展,必须在本地自然资源条件和自身经济的可持续发展前提下,采取尽可能大的努力,实现较低温室气体排放,主要体现在:将吉林市的产业结构调整到一个低能耗、高效率的状态;通过多种激励政策和措施,促进节能减排、普及先进高效技术、以及大力发展可再生能源技术和核电技术;促进低碳生产方式、低碳消费方式和低碳生活方式成为一种社会的普遍行为,最终实现大规模减排温室气体目标,以利于吉林市政府和相关决策部门更全面、系统、并力求实际地展望和创造自己未来的低碳发展之路。  相似文献   

10.
王勇 《科技通报》2012,28(3):9-11
本文得到最大值α和最小值β,使得对所有的a,b>0,a≠b双向不等式αC(a,b)+(1-α)A(a,b)相似文献   

11.
流传于西北民间的贤孝艺术,作为国家级非物质文化遗产,具有鲜明的艺术特色、独特的文化价值和积极的社会功能,其隐恶扬善的道德取向对构建和谐社会有一定的启示意义。由于社会环境的发展变化,民间艺术受到了极大的冲击,贤孝艺术也陷入了前所未有的困境,如何保护、传承、革新和发展贤孝艺术,是一个迫切的现实问题。作者对此进行了思考,并提出了具体的措施,以期能对贤孝的生存与发展找到可行的途径,并对其他民间传统文化的传承发展提供借鉴。  相似文献   

12.
Critics have argued that information and communication technologies (ICTs) disconnect people from their social networks and reduce public participation. Research in support of this perspective has been biased by two assumptions. The first is a tendency to privilege the Internet as a social system removed from the other ways people communicate. The second is a tendency to favor broadly supportive strong social ties. Survey and ethnographic observations from Netville, a 2-year community networking experiment, suggest that weak, not strong ties experience growth as a result of ICTs. By examining a unique and underexplored stage in the life cycle of a community networking project, the end of a networking trial, this article demonstrates how ICTs facilitate community participation and collective action (a) by creating large, dense networks of relatively weak social ties and (b) through the use of ICTs as an organizing tool.  相似文献   

13.
User-model based personalized summarization   总被引:3,自引:0,他引:3  
The potential of summary personalization is high, because a summary that would be useless to decide the relevance of a document if summarized in a generic manner, may be useful if the right sentences are selected that match the user interest. In this paper we defend the use of a personalized summarization facility to maximize the density of relevance of selections sent by a personalized information system to a given user. The personalization is applied to the digital newspaper domain and it used a user-model that stores long and short term interests using four reference systems: sections, categories, keywords and feedback terms. On the other side, it is crucial to measure how much information is lost during the summarization process, and how this information loss may affect the ability of the user to judge the relevance of a given document. The results obtained in two personalization systems show that personalized summaries perform better than generic and generic-personalized summaries in terms of identifying documents that satisfy user preferences. We also considered a user-centred direct evaluation that showed a high level of user satisfaction with the summaries.  相似文献   

14.
Performance of text classification models tends to drop over time due to changes in data, which limits the lifetime of a pretrained model. Therefore an ability to predict a model’s ability to persist over time can help design models that can be effectively used over a longer period of time. In this paper, we provide a thorough discussion into the problem, establish an evaluation setup for the task. We look at this problem from a practical perspective by assessing the ability of a wide range of language models and classification algorithms to persist over time, as well as how dataset characteristics can help predict the temporal stability of different models. We perform longitudinal classification experiments on three datasets spanning between 6 and 19 years, and involving diverse tasks and types of data. By splitting the longitudinal datasets into years, we perform a comprehensive set of experiments by training and testing across data that are different numbers of years apart from each other, both in the past and in the future. This enables a gradual investigation into the impact of the temporal gap between training and test sets on the classification performance, as well as measuring the extent of the persistence over time. Through experimenting with a range of language models and algorithms, we observe a consistent trend of performance drop over time, which however differs significantly across datasets; indeed, datasets whose domain is more closed and language is more stable, such as with book reviews, exhibit a less pronounced performance drop than open-domain social media datasets where language varies significantly more. We find that one can estimate how a model will retain its performance over time based on (i) how well the model performs over a restricted time period and its extrapolation to a longer time period, and (ii) the linguistic characteristics of the dataset, such as the familiarity score between subsets from different years. Findings from these experiments have important implications for the design of text classification models with the aim of preserving performance over time.  相似文献   

15.
The increasing number of documents that have to be indexed in different environments, particularly on the Web, and the lack of scalability of a single centralised index lead to the use of distributed information retrieval systems to effectively search for and locate the required information. In this study, we present several improvements over the two main bottlenecks in a distributed information retrieval system (the network and the brokers). We extend a simulation network model in order to represent a switched network. The new simulation model is validated by comparing the estimated response times with those obtained using a real system. We show that the use of a switched network reduces the saturation of the interconnection network, especially in a replicated system, and some improvements may be achieved using multicast messages and faster connections with the brokers. We also demonstrate that reducing the partial results sets will improve the response time of a distributed system by 53%, with a negligible probability of changing the system’s precision and recall values. Finally, we present a simple hierarchical distributed broker model that will reduce the response times for a distributed system by 55%.  相似文献   

16.
“优势互补,共建双赢”是新时期处理行政区与开发区关系的一致思路。在当前开发区法律地位不甚明朗的情况下,探索二者的和谐发展问题具有深刻的时代价值。在把握全国范围内开发区管理“由分散管理向集中管理转变、由单一功能向多元功能转变”这一宏观背景的同时,针对当前雁塔区“一个行政区内建有多个开发区,一个开发区跨越多个行政区”的状况,积极寻求行政区与开发区之间实质性融合共建的体制机制,不仅符合深入贯彻落实科学发展观和构建社会主义和谐社会的基本要求,而且所形成的相关模式对全市、全省乃至全国更有示范作用和借鉴价值。  相似文献   

17.
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   

18.
王红明 《科教文汇》2014,(14):209-209
高校作为创新知识和繁荣文化的重要场所,是社会培养专业人才的阵地。衡量大学办学水平的重要标志就是是否为社会培养出了一批高质量、高素质的创新人才。校友作为高校的"人才产品"和"品牌形象",已经成为了一张张高校改革发展和核心竞争力的名片。校友作为一个信息丰富、知识密集与母校有着特殊感情联系的群体性资源,必将会成为高校改革发展的特殊资源,在提升学校声誉,凝聚学校力量,传承学校人脉,提供发展空间等方面发挥着不可替代的作用。  相似文献   

19.
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   

20.
Metrics derived from user visits or sessions provide a means of evaluating Websites and an important insight into online information seeking behaviour, the most important of them being the duration of sessions and the number of pages viewed in a session, a possible busyness indicator. However, the identification of session (termed often ‘sessionization’) is fraught with difficulty in that there is no way of determining from a transactional log file that a user has ended their session. No one logs out. Instead a session delimiter has to be applied and this is typically done on the basis of a standard period of inactivity. To date researchers have discussed the issue of a time out delimiter in terms of a single value and if a page view time exceeds the cut-off value the session is deemed to have ended. This approach assumes that page view time is a single distribution and that the cut-off value is one point on that distribution. The authors however argue that page time distribution is composed of a number of quite separate view time distributions because of the marked differences in view times between pages (abstract, contents page, full text). This implies that a number of timeout delimiters should be applied. Employing data from a study of the OhioLINK digital journal library, the authors demonstrate how the setting of a time out delimiter impacts on the estimate of page view time and the number of estimated session. Furthermore, they also show how a number of timeout delimiters might apply and they argue that this gives a better and more robust estimate of the number of sessions, session time and page view time compared to an application of a single timeout delimiter.  相似文献   

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