基于RFID技术的肉牛养殖质量安全可追溯系统研究

消费者和国际贸易对食品质量的要求日益提高,而运用监控、预警、追踪、追溯等技术在食品生产的关键环节上进行的质量监控是有效保障食品质量安全的重要手段。研究采用B/S（浏览器/服务器）模式结构体系,基于RFID技术构建了肉牛养殖可追溯系统。系统通过应用RFID技术,实现了对每头肉牛的养殖信息的自动采集,并针对每头肉牛形成可在Internet网络上进行查询的质量追溯档案。解决了牛肉在肉牛养殖环节（牛肉生产源头）上进行以肉牛个体为单位实施质量监控和实现可追溯的问题。     

Improving integrity of on-line grammage measurement with traceable basic calibration

The automatic control of grammage (basis weight) in paper and board production is based upon on-line grammage measurement. Furthermore, the automatic control of other quality variables such as moisture, ash content and coat weight, may rely on the grammage measurement. The integrity of Kr-85 based on-line grammage measurement systems was studied, by performing basic calibrations with traceably calibrated plastic reference standards. The calibrations were performed according to the EN ISO/IEC 17025 standard, which is a requirement for calibration laboratories. The observed relative measurement errors were 3.3% in the first time calibrations at the 95% confidence level. With the traceable basic calibration method, however, these errors can be reduced to under 0.5%, thus improving the integrity of on-line grammage measurements. Also a standardised algorithm, based on the experience from the performed calibrations, is proposed to ease the adjustment of the different grammage measurement systems. The calibration technique can basically be applied to all β-radiation based grammage measurements.     

Miniaturized Two-Pressure Generator for Relative Humidity

The concept and design of a miniaturized two-pressure humidity generator are presented. The generator is suitable for achieving relative humidity ranging from 10% to 95% with uncertainties of under 1% at ambient temperature and can be used for the calibration of relative humidity instruments in the laboratory and on site. By virtue of the concept, the relative humidity achieved is traced to only two pressure measurements. Further references are not necessary. A special adjustment algorithm enables standard industrial pressure sensors to be used. The two pressure sensors are synchronized by aligning their readings at ambient pressure. The resulting correlation of the uncertainties leads to very small systematic errors in the humidity display. Each humidity generator can still be individually adjusted through comparison with a chilled-mirror hygrometer, the total uncertainty of the generator being largely determined by the uncertainty of this hygrometer. Any drift of the pressure sensors that occurs can be compensated at any time by performing an alignment at ambient pressure without changing the individual adjustment of the generator. It can be demonstrated that the uncertainty of the displayed humidity remains practically unchanged over the course of a year by virtue of this alignment process.     

微纳力值计量标准的研究和溯源体系的建立

微牛、纳牛范围力值计量研究是目前国际计量领域的重要研究发展方向。总结了美国标准技术研究院、英国国家物理实验室、德国物理技术研究院、韩国标准和科学研究院等研究机构近年来研制的可溯源到SI的微纳力值标准装置、微纳力值传感器、参考悬臂梁以及微纳力值溯源方法。提出了微纳力值溯源体系的框架,为新材料、生物、微电子等各应用领域微纳力学特性计量量值溯源提供了技术保证。     

Application of traceable sample area measurement in the calibration of online dry grammage measurement used in board production

A method is described for the simultaneous calibration of online grammage and moisture measurement by applying machine reel sampling and traceable sample area measurement. The area measurement is based on a flatbed scanner and image analysis. It is demonstrated that a relative uncertainty of 0.5% can be achieved in dry grammage calibration at the 95% confidence level. The determination of grammage and moisture were performed by applying the EN ISO 536 and the EN ISO 287 standards, respectively. The described technique can also be applied with the calibrations performed for the paper industry.     

图形人机接口的形式化描述

本文讨论了人机接口的分类及特点，着重介绍了图形人机接口的重要性及实用性；引入了回溯自动机作为定义人机接口的一种抽象数学模型，并采用该模型给出其图形人机接口的形式化描述。     

K_(1.3)—Free图成为可遍历的一个邻域并条件

在本文中,我们给出了下列定理:设G是阶为n≥3的连通K_(13)—Free图且NC(G)≥n—δ—2。则G是可遍历的。     

Traceable atomic force microscope based on monochromatic light interference

Atomic force microscope (AFM) is widely applied to the measurement of the micro-nano structures due to its three-dimensional spatial resolution of sub-nanometer. However, the height measurement traceability in the z-axis is complex to be implemented in conventional AFMs. In this paper, a traceable AFM is developed based on the monochromatic light interference (MLI) principle without probe calibration. The height change of the AFM's probe is directly detected by extracting the phase change of the MLI fringes on the probe tip with the Hilbert transform based phase extraction algorithm, and the three-dimensional surface topography is reconstructed with a surface recovery algorithm. The configuration of tracing to the wavelength of the monochromatic light in real-time further improves the measurement accuracy of the MLI-AFM. A prototype MLI-AFM is established to demonstrate its measurement accuracy enhancement.     

Effects of the perception of traceable fresh food safety and nutrition on perceived health benefits,affective commitment,and repurchase intention

Because numerous food safety problems have gained public attention, consumers are now focused on food safety and nutrition as well as health benefits. While traceability is considered the most effective intervention to ensure food safety, understanding how to encourage consumers to purchase traceable fresh food (TFF) is crucial in developing the safe food market. A questionnaire survey was conducted in Taiwan to explore the effects of the perception of TFF safety and nutrition on perceived health benefits, affective commitment, and repurchase intention. TFF consumers, defined as those who had purchased TFF in the past three months, were asked to participate in the study; in total, 393 valid questionnaires were collected. Results of structural equation modeling analysis indicated that consumers’ TFF safety and nutrition perception affected their health benefit perceptions, which consequently influenced their affective commitment to TFF and repurchase intentions. These findings explain how TFF repurchase intentions are influenced by TFF safety and nutrition perception and health benefit perceptions. This paper provides some practical suggestions for TFF marketers to increase TFF consumption.     

基于对的无线Ad hoc网络可追踪邻居匿名认证方案

为解决传统无线Ad hoc网络邻居匿名认证方案容侵性不佳以及难以锁定恶意节点身份的问题,提出一种基于双线性对的无线Ad hoc网络可追踪邻居匿名认证方案。采用基于身份的公钥系统,节点随机选择私钥空间中的数作为临时私钥,与身份映射空间的节点公钥以及一个公开的生成元模相乘得到临时公钥,利用双线性映射的性质协商会话密钥并实现匿名认证。通过在随机预言机模型下的形式化分析,表明本方案在BCDH问题难解的假设下可对抗攻击者的伪装行为,同时利用认证过程中交互的临时公钥可有效锁定恶意节点真实身份。