灰色预测法在情报研究中的应用研究综述     

张晶晶  李泽霞 《图书情报工作》2020,64(24):106-114

[目的/意义] 灰色预测法可有效处理情报研究中广泛存在的小样本数据，通过对灰色预测法在情报研究中的应用情况进行梳理，总结其在应用过程中存在的不足，为灰色预测法在情报研究中的进一步应用提供参考。[方法/过程] 通过综述情报研究中涉及灰色预测法的相关文献，从数据选取、模型构建和解决的问题等方面对情报研究中灰色预测法的应用进行概述，总结当前情报研究中灰色预测法的应用所存在的问题，并提出改进建议。[结果/结论] 在方法应用上，已有研究主要采用数列灰预测，且模型集中在单变量灰色预测模型，根据预测对象不同，灰色预测法已经在包括期刊分析、图书馆运行管理、热点主题分析及科研机构评价方面得到了很好的应用，未来可根据预测对象特点及研究目标尝试不同的灰色预测方法，扩宽灰色预测法在其他方面的情报研究问题中的应用。  相似文献   

上海国际航运中心建设支持政策的量化评价     

张婕姝  陈靖瑶 《上海海事大学学报》2020,41(1):116-121

为增强上海国际航运中心建设支持政策的有效性,基于2009—2018年间国家及地方政府层面颁布的19个涉及上海国际航运中心建设的政策文本,应用文本挖掘方式提取评价指标,构建PMC指数模型对政策进行量化评价。分别选取3项针对性政策和3项辅助性政策作为评价对象进行实证分析,结果表明:针对性政策的PMC指数总得分高于辅助性政策的PMC指数总得分,且随着上海国际航运中心建设的不断推进,其引导作用不断加强;辅助性政策虽然只考虑到上海国际航运中心的部分建设需求,但在保障激励等方面给予了高度重视。  相似文献   

主客观信息融合的港口综合能源系统评价指标体系     

何大春  谈健  苏宜强  解翔  宋天立  蔡超  陈曦 《上海海事大学学报》2020,41(3):110-116

为建立绿色港口，实现港口的节能环保，对港口综合能源系统(port integrated energy system，PIES)的评价方法进行研究，提出一种主客观信息融合的PIES评价指标体系，将主观评价与数理统计模型进行结合，兼顾评价过程中的主客观因素，并采用基于马氏距离的统计检验方法对评分矩阵进行修正，实现对PIES的全面评价。通过青岛港董家口港区的调研数据，验证该方法的有效性。  相似文献   

基于隐马尔科夫模型的VLCC目的港预测     

杨春  王一丹  徐晖  胡勤友  潘亚兰 《上海海事大学学报》2020,41(4):42-49

超大型油船(very large crude carrier，VLCC)目的港预测对海运原油流向预测以及货源地未来运力估计具有重要作用。针对VLCC的AIS目的港信息存在缺失、更新不及时、不准确等现象，提出一种基于隐马尔科夫模型的VLCC目的港预测方法。分析船舶AIS轨迹数据，得到油船历史停靠港口序列；根据VLCC轨迹提取习惯航路，以航路中的交叉点为依据设置观测线；利用船舶航行轨迹数据判断船舶是否经过观测线以及经过观测线的方向，对不同方向分别计算船舶在挂靠港间的转移概率矩阵和船舶挂靠港与观测线间的输出概率矩阵，建立VLCC目的港预测模型并进行预测。研究结果表明：在大多数情况下VLCC目的港预测的准确率可以达到70%以上；航线越固定、运行越规律的船舶，预测准确率越高；船舶越靠近目的港，预测越准确；重载状态下的船舶目的港预测更准确。  相似文献   

基于深度学习的SSD模型尾矿库自动提取     

闫凯  沈汀  陈正超  闫弘轩 《中国科学院大学学报》2020,37(3):360-367

针对华北地区尾矿库自动提取问题，将基于深度学习的SSD目标检测模型应用于遥感图像尾矿库提取。首先标记华北地区2 000个样本，随机挑选1 500个作为训练样本，剩余样本作为测试样本，验证模型的检测精度。分析卷积层对应感受野与图像中尾矿库尺寸关系，发现原始SSD模型漏检误检大型尾矿库。改进SSD模型结构，提出增加额外卷积层的策略，提高对大型尾矿库目标的检测精度。实验表明，在置信度阈值为0.3时，改进的SSD模型相比原始模型，检测精确率提高10.0%，召回率提高14.4%，提高了大型尾矿库检测精度。验证了基于深度学习的SSD目标检测模型自动提取尾矿库的可行性以及改进算法的有效性。  相似文献   

基于距离方程组的机载SAR图像立体定位方法     

潘志刚  王超  曹舸 《中国科学院大学学报》2020,37(6):798-804

提出一种基于距离方程组的机载SAR图像立体定位方法，该方法使用同一成像区域的3幅SAR图像进行无控制点定位，首先确定目标在3幅图像中对应的同名像点，解析该像点对应的雷达平台瞬时经纬度坐标、海拔高度以及目标到雷达平台的斜距值，在地心坐标系下建立3幅图像对应同名像点的距离方程组，对非线性方程组进行求解得到同名像点基于地心坐标系的坐标值，并通过坐标转换得到目标点的经纬度坐标及海拔高度，实现三维定位。对影响定位精度的系统误差因素进行仿真分析，利用实飞的机载SAR图像进行目标定位实验，结果验证了该方法的有效性。  相似文献   

An extension of the technology acceptance model in the big data analytics system implementation environment     

Surabhi Verma  Som Sekhar Bhattacharyya  Saurav Kumar 《Information processing & management》2018,54(5):791-806

Research on the adoption of systems for big data analytics has drawn enormous attention in Information Systems research. This study extends big data analytics adoption research by examining the effects of system characteristics on the attitude of managers towards the usage of big data analytics systems. A research model has been proposed in this study based on an extensive review of literature pertaining to the Technology Acceptance Model, with further validation by a survey of 150 big data analytics users. Results of this survey confirm that characteristics of the big data analytics system have significant direct and indirect effects on belief in the benefits of big data analytics systems and perceived usefulness, attitude and adoption. Moreover, there are mediation effects that exist among the system characteristics, benefits of big data analytics systems, perceived usefulness and the attitude towards using big data analytics system. This study expands the existing body of knowledge on the adoption of big data analytics systems, and benefits big data analytics providers and vendors while helping in the formulation of their business models.  相似文献   

Online social viewing: Cross-cultural adoption and uses of bullet-screen videos     

Anan Wan  Leigh Moscowitz  Linwan Wu 《Journal of International and Intercultural Communication》2020,13(3):197-215

ABSTRACT

Bullet-screen technology, an innovative way of interacting with online videos, allows viewers to contribute comments that simultaneously appear over videos. Popular in East Asia, the technology is making its way to American audiences. This study employed a comparative qualitative focus group approach to explore how American and Chinese viewers responded to and interacted with this new format of online videos. Three themes emerge from this investigation: (1) the unique affordances of this technology; (2) barriers to adoption and usage; and (3) cultural differences that impact the user experience. The theoretical and practical implications for bullet-screen technologies are discussed.  相似文献   

Limitations on the human capital transferability of adult migrants in Spain: Incentive or barrier for a new investment in education?     

Jacobo Muñoz-Comet  María Miyar-Busto 《European Journal of Education》2018,53(4):586-599

Many empirical studies on immigrant integration document the benefits of an education acquired in the country of destination. In this article; we study how the degree of human capital transferability affects an immigrant's chances of studying in Spain. We used data from the Spanish Labour Force Survey (2008–2015) for a sample of adults aged 18–55 who had left the educational system. The main findings show that natives are the ethnic group with the highest likelihood of re-enrolling in education. Amongst immigrants, those with fewer limitations on human capital transferability also invest more. These results question the predictions of the Immigrant Human Capital Investment model which expect that immigrants whose human capital depreciates upon arrival and those who can obtain a higher return on a new investment in education are therefore more likely to study. Moreover, the effect of skill transferability differs depending on the type of obstacle and the kind of education. Immigrants with less linguistic and cultural familiarity with the host country are less likely to undertake non-formal education than formal education. However, when the transferability obstacles are related to administrative requirements and legal restrictions, the probability of investing in non-formal education is higher. We conclude that immigrants with low skill transferability are not only less well integrated in the labour market upon arrival, but are also less able to redress that disadvantage through a new investment in education.  相似文献   

Location extraction from tweets     

Thi Bich Ngoc Hoang  Josiane Mothe 《Information processing & management》2018,54(2):129-144

Five hundred million tweets are posted daily, making Twitter a major social media platform from which topical information on events can be extracted. These events are represented by three main dimensions: time, location and entity-related information. The focus of this paper is location, which is an essential dimension for geo-spatial applications, either when helping rescue operations during a disaster or when used for contextual recommendations. While the first type of application needs high recall, the second is more precision-oriented. This paper studies the recall/precision trade-off, combining different methods to extract locations. In the context of short posts, applying tools that have been developed for natural language is not sufficient given the nature of tweets which are generally too short to be linguistically correct. Also bearing in mind the high number of posts that need to be handled, we hypothesize that predicting whether a post contains a location or not could make the location extractors more focused and thus more effective. We introduce a model to predict whether a tweet contains a location or not and show that location prediction is a useful pre-processing step for location extraction. We define a number of new tweet features and we conduct an intensive evaluation. Our findings are that (1) combining existing location extraction tools is effective for precision-oriented or recall-oriented results, (2) enriching tweet representation is effective for predicting whether a tweet contains a location or not, (3) words appearing in a geography gazetteer and the occurrence of a preposition just before a proper noun are the two most important features for predicting the occurrence of a location in tweets, and (4) the accuracy of location extraction improves when it is possible to predict that there is a location in a tweet.  相似文献