怎样区分塑料袋有毒无毒

薄膜塑料袋有物品包装袋和食品袋两种,都已普遍使用。作包装袋的材料是聚氯乙烯化学原料。这种原料往往要加添加剂,其中含有铅及各种杂环类有毒物质,不能用来装食品。塑料薄膜食品袋的     

基于RFID的室内物品定位系统设计与实现

针对室内物品定位难的问题,设计了室内物品定位系统。详细介绍了系统功能,并阐述了系统硬件结构设计思路。在系统设计过程中采用RFID技术实现物品信息采集,使用蛛网定位算法完成物品定位工作,最终实现室内物品定位系统设计。室内定位系统节省了大量人力,减少了定位成本和定位时间,提高了定位效率。     

企业数据向善:概念、测量与展望

近年来频发的大数据杀熟、隐私泄露等数据安全事件,促使实业界和学术界开始反思企业如何合理使用数据,用数据来做好事,企业数据向善成为极具研究潜力和研究价值的新领域。本研究首先明确了企业数据向善的概念,将其划分为负责任的使用数据和数据慈善两个维度,并回顾了企业社会责任、资源基础观、负责任的研究与创新、公共物品等基础理论,在此基础上开发企业数据向善量表,最后提出企业数据向善未来研究的五大议题。本研究丰富和拓展了企业数据向善理论研究,为未来的企业数据向善研究执炬,不仅对学术界关注企业数据向善问题具有启发意义,而且对实业界实施数据向善造福社会具有启示意义。     

基于YOLOv5的疲劳与危险驾驶行为检测系统研究

疲劳驾驶和危险驾驶是造成交通事故的主要原因，文章基于YOLOv5目标检测算法和dlib人脸识别库，分别从人脸朝向、位置、眼睛开合度、眨眼频率、驾驶员手持物品定位，分析物品形态、物品大小等数据，通过这些数据，利用YOLOv5算法实时地计算出驾驶员是否存在疲劳驾驶和危险驾驶的行为，若存在则通过系统及时给出相应的安全提示。     

基于STM32的智能仓库寻物系统设计

针对传统仓库依靠人工寻找物品低效而且缓慢的问题,特别是物品种类越复杂繁多,问题就越突出。本文结合无线数传技术和嵌入式ARM技术,设计了一种主从模式智能仓库寻物系统。实现了使用手持终端对仓库物品查询并自动获得所寻物品方位,同时具有所在方位发出声光提醒的功能。使用该系统可以较大的提高复杂仓库寻物的速度与准确性,具有良好的实用性、扩展性和低廉的价格。     

基于公共物品属性的供给方式分析

本文从公共物品的属性出发分析了公共物品政府供给和市场供给方式。通过对两种供给方式的分析,发现了其存在的问题,探索了政府解决市场供给问题的方法。意在实现公共物品供给过程中既发挥市场配置效率优势,又实现政府维护和监管方面的优势。     

基于元数据的数据发现和数据评价

元数据在信息资源发现过程中发挥了重要作用。科学数据元数据也不例外,它为用户发现、评价和再利用科学数据提供了依据。本文在阐述科学数据和科学数据元数据内涵的基础上,对科学数据的用户需求进行了分析,重点分析了用户查找与发现科学数据的过程,此外,本文针对如何完善科学数据元数据提出建议,以促进用户对科学数据的发现和使用。     

科研数据开放共享的经济逻辑与制度安排

明晰科研数据开放共享的经济逻辑并据此进行相应的制度安排,可为规范科研数据管理与挖掘数据服务于科研、经济与社会的潜能提供理论借鉴和实践参考。从分析科研数据的物品属性及其开放共享的实质出发,提出科研数据分阶段开放共享制度。采用成本收益分析法解析其经济逻辑,并与其他科研数据管理与共享方式进行福利比较,发现分阶段开放共享是现阶段科研数据管理可付诸实践且能实现更高福利水平的制度安排。最后针对产权界定、科研数据交易共享平台建设、收费期节点等关键问题做具体制度安排。     

奇特的风炮

1945年，盟军战胜法西斯德国后，经常从德军手里接收各种稀奇古怪的新式兵器。其中有一件东西令人百思不得其解，它就是在德国海拉斯列洪靶场发现的物品。盟军指挥部组织了一个调查组，经过调查后发现，这是纳粹德国的新兵器，名叫风炮。     

用于检测的操作框架的设计与分析

目前计算机应用的日益广泛,可靠性也越来越得到关注,为了在可靠性评测中提高检测效率,本文主要研究从使用数据和要使用数据的假设中抽取出操作框架,并且使用状态图来模型化这个结构。我们提出了一个系统的单步过程方法来设计开发软件组件的操作框架。这种方法运用了要使用的假设和使用数据来发现一种使用框架和使用分布。     

The role of digital information use on student performance and collaboration in marginal universities

Using technology to facilitate learning in universities and other higher education institutions (HEIs) has become common practice due to its ability to reduce barriers related to time and space in traditional learning environments. However, current literature mostly focuses on the use of the technology and not on the use of the information it conveys. Also, very few studies focus on technology adoption in universities and HEIs in developing countries, especially those in Africa. Thus, we propose a model that explains the changing information behaviors of students in this digital age and the effect this has on their learning outcomes. We collected questionnaire data from 303 students and analyzed the data using structural equation modelling partial least squares (SEM-PLS). We found that our proposed model explains 60.2 % of student satisfaction, 24.2 % of academic performance, 24.1 % of information sharing, and 19.8 % of their information exchange behavior. This study confirms that the use of digital information and its antecedent factors have significant effects on the college experience of students. This has several implications for information systems research and practice, especially in the design and assessment of technology use in learning environments.     

未来区域土地利用驱动力研究的重要命题：尺度依赖

尺度问题的处理是亚全球土地利用情景分析中一个复杂而又关键的新前缘。现有研究实现了尺度转换或尺度效应,加深了人们对土地利用驱动因素的多时空变化的理解和认识。但土地利用的信息和过程特征使得众多研究主题局限于某一领域。要实现不同尺度间土地利用数据信息的转换,理解不同尺度众多驱动因素间的作用过程,并正确描述土地利用轨迹,未来与土地利用有关的尺度问题应注重尺度推绎：①借助高分辨率,局地数据和低分辨率,区域数据的结合获取多空间尺度数据信息,减少尺度转换过程中土地利用数据的损失;②把握土地利用不同类型和方式间的流向,识别诱导其发生演变的主导驱动变量及其相互作用;③理解土地利用效应的跨尺度相互作用对环境管理的影响,弄清局地效应放大和区域影响根植于局地的过程;④考虑土地利用政策的跨尺度交互作用,联合自上而下和自下而上的方法确定不同尺度间政策运用新问题的解决思路。这些问题以及它们间的复杂依赖性,仍然是理解土地利用及其影响间的间接和跨尺度链接所面临的挑战。     

用水量与经济增长关系的实证研究

利用1998-2012年中国省际面板数据模型,整体和分组检验不同类别用水量与经济增长的关系。分析发现,用水量与经济增长的关系具有多种表现形态,与地区和用水类别密切相关,全国组别的总用水和工业用水、东部组别的工业用水、中部组别的工业用水、西部组别的总用水与经济增长之间呈现倒“U”型形态;各省份当前用水量所处现状存在较大差异,需要警惕用水量下降后再次上升的“反弹效应”。同时,本文对31个省份的时间序列进行回归检验,发现倒“U”型形态普遍存在,且发达地区拐点值大于欠发达地区;另外,对部分年份的截面数据进行非参数估计,与参数估计结果具有差异性。因此,各地区对待不同的用水类别,需要制定差异化的政策以促使用水量保持稳定或下降,避免出现“反弹效应”;加大对欠发达地区的政策倾斜,支持帮助其跨过拐点实现用水量的下降。     

The dynamic effect of interactivity on customer engagement behavior through tie strength: Evidence from live streaming commerce platforms

Interactivity, which is a key characteristic of the live streaming commerce environment, fosters users’ active attitudes and behaviors in communications and transactions. However, the literature on live streaming commerce, is scarce, and few studies examine how interactivity influences customers’ non-transactional behaviors from a dynamic perspective. In this setting, based on the stimulus-organism-response (S-O-R) framework, we developed a research model using real-time data to investigate the dynamic effect of interactivity on customer engagement behavior through tie strength in live streaming commerce, which is a relatively new derivative of social commerce. This study developed a text mining method to quantify constructs using a large-scale sample of 3,500,445 online review texts. Our empirical study found that interactivity has a curvilinear relationship with customer engagement behavior. Besides, tie strength plays an intermediary role between interactivity and customer engagement behavior. It was further observed that both tenure of membership and popularity have an important moderating relationship between interactivity and tie strength. The study enriches the relationship marketing theory and live streaming commerce literature. Moreover, this study is one of the first studies to use real-time online data for live streaming commerce research.     

The role of positive and negative valence factors on the impact of bigness of data on big data analytics usage

The number of firms that intend to invest in big data analytics has declined and many firms that invested in the use of these tools could not successfully deploy their project to production. In this study, we leverage the valence theory perspective to investigate the role of positive and negative valence factors on the impact of bigness of data on big data analytics usage within firms. The research model is validated empirically from 140 IT managers and data analysts using survey data. The results confirm the impact of bigness of data on both negative valence (i.e., data security concern and task complexity), and positive valence (i.e., data accessibility and data diagnosticity) factors. In addition, findings show that data security concern is not a critical factor in using big data analytics. The results also show that, interestingly, at different levels of data security concern, task complexity, data accessibility, and data diagnosticity, the impact of bigness of data on big data analytics use will be varied. For practitioners, the findings provide important guidelines to increase the extent of using big data analytics by considering both positive and negative valence factors.     

Innovation and productivity among heterogeneous firms

This paper examines the links between firm innovation and productivity using the largest cross-country panel dataset assembled for this purpose to date. We use harmonized and comparable data on a total of 40,577 small, medium and large firms surveyed in the World Bank Enterprise Surveys (WBES) and provide some support for the reported patterns previously found in the innovation literature. Our results indicate that estimates from studies using cross-section data may be upward biased but nevertheless, innovative firms are significantly and economically more productive in both the manufacturing and services sectors.     

Excel逻辑函数在实践中的应用

逻辑函数是Excel函数的重要组成部分,逻辑函数的使用可以进行真假值的判断及进行复合检验,有效地使用逻辑函数可以极大地提高工作效率,给人们的数据处理带来极大便利。通过分析在实践中经常会遇到的案例,对逻辑函数的使用进行了分析,提出了逻辑函数灵活运用的方法。     

中国工业用地利用效率收敛特征

研究工业用地利用效率的收敛特征对于推动区域均衡发展、促进全域性的工业用地利用效率提升具有重要意义。本文在科学界定工业用地利用效率内涵的基础上,基于随机前沿分析框架测度了中国大陆各省级行政区2000—2015年间的工业用地利用效率,采用空间计量方法进行了β收敛分析和俱乐部收敛分析,并考察了影响工业用地利用效率提升和稳态形成的因素。研究结果表明：①工业用地利用效率存在着β收敛和σ收敛,收敛速度为0.143,且地区间工业用地利用效率增长存在着显著的相互影响;②经济发展水平、研发投入和对外开放水平等因素对工业用地利用效率的提升和稳态的形成具有显著影响;③基于Moran散点图的探索性空间数据分析将各省级行政区划分为HH组、LL组和LH组这3个区域组,工业用地利用效率在各区域组内均存在着俱乐部收敛,收敛速度分别为0.289、0.149和0.196,均快于中国大陆整体的收敛速度。     

The use of information by environmental planners: A qualitative study using Grounded Theory methodology

The purpose of this study was to examine the use of information by environmental planners. The study used the Grounded Theory method to develop a theoretical model that explains the reasons for using information and the factors that motivate such use. Forty-four semi-structured interviews were conducted in workplace environments to collect data on the way the respondents used information in projects that they had done before. Data were analysed in accordance with the Grounded Theory techniques of constant comparison. The study found that the planner’s perceptions of: their own competences, resistance of the stakeholders, role requirement; and the impressions on the enabling effect of the information environment drive the self-empowerment behaviour of the planners. This behaviour is characterised by actions involving information acquisition, packaging as well as giving information to stakeholders during the facilitation of the environmental planning process. The experiential knowledge levels of individuals enhance the self-empowerment behaviour exhibited by environmental planners. Based on the informational power derived from the self-empowerment activities, the planners select a strategy for participation that they deem appropriate for an environmental planning project, consequently facilitating the process to develop widely accepted environmental plans.     

The maximum entropy approach to record abbreviation for optimal record control

This paper presents an entropy based technique for the abbreviation of text strings for use as a control code. Tests were performed using titles from machine readable bibliographic files. Greater than 94% of the titles have been found to generate a unique seven character code.