Medicinal and illegal drugs among Danish car drivers

The objective of this study was to get an insight into the prevalence of medicinal and illegal drugs among car drivers in a Danish rural area. The police randomly stopped about 1000 car drivers and asked them to deliver a saliva sample and gave them a questionnaire to fill in at home. Laboratory analyses by specific methods of samples, which a screening found positive, confirmed that 2% were positive for benzodiazepines or illegal drugs (amphetamine, cannabis, cocaine or opiates): 1.3% were positive for illegal drugs and 0.7% for benzodiazepines. Questionnaire statements from some of the drivers confirm that occasionally some of these drive despite a suspicion to be under the influence of an illegal drug (2.8%), an illegal drug including alcohol (4%), a hazardous medicinal drug including alcohol (8.5%), or alcohol alone above the legal limit (24.5%). These results are considered reliable for the survey area and may not reflect national conditions. The overall results indicate that in this study driving under the influence of illegal drugs or alcohol seems to be associated to especially men, aged 22–44 years. Driving under the influence of hazardous medicinal drugs seems to be associated to middle-aged/elderly drivers, both men and women.     

一种新的基于边缘检测的错误隐藏算法

利用传统空间内插方法对图像中的丢失块进行差错隐藏时,容易在人眼敏感的边缘区域产生模糊.笔者提出了一种新的结合边缘检测的空域内插办法,能在保留边缘的情况下根据边缘对图像的划分对图像进行分区内插.试验表明在具有明显边缘的区域,使用该办法能够得到满意的隐藏效果,其PSNR比传统内插方法提高大约1～2 dB.同时对于存在多边缘的图像,也提出了一种通用的方法进行差错隐藏,并取得了较好的主观效果.     

基于PSO算法的神经网络集成入侵检测系统

在系统结构上提出了一种多检测器并行的智能机群入侵检测系统模型，系统中每一个检测器是一个神经网络集成分类检测器，由多个PC组成，以提高系统响应速度。采用两次粒子群优化算法选择性集成神经网络集，提高了神经网络集成检测器的预测精度。程序设计采用PVM并行方式实现。     

Formation of white spots in the shell of raw shrimps during frozen storage. Seasonal variation and effects of some production factors

During frozen storage of raw pink shrimps, Pandalus borealis, calcium carbonate tends to precipitate in the exoskeleton, giving the shrimps a spotted appearance. Seasonal variations in the formation of white spots and the influence of shrimp size, production time, chemical treatment, and storage temperature on white spot formation was determined. A significant effect (P=0·003) of day of catch was observed and shrimps caught in the summer period showed a greater tendency of white spot formation than shrimps caught during the rest of the year. Treatment in a sulphite, a phosphate or a phthalate solution prior to freezing retards calcium carbonate crystallisation (P<0·05) while treatment in a borax solution promotes crystallisation (P<0·05). Prolonged time from catch to chemical treatment and increased storage time increase the risk of white spot formation. Storage temperature has a significant effect on white spot formation for which process the rate at different temperatures was described by the Arrhenius equation with a high energy of activation of 90 kJ mol⁻¹. The size (age) of the shrimps did not influence white spot formation (P=0·69). From these findings it is concluded that calcium carbonate precipitation resulting in white spots in shrimp shell can be retarded or possibly prevented by short production time, appropriate chemical treatment and very low storage temperature. ©1997 SCI     

远程处理技术在校园网络考试系统中的应用

设计了一个用远程处理技术实现的网络考试系统。充分利用微软最新的远程分布式访问技术———远程处理高效性与可扩展性,结合密码技术保证了考试系统中信息传输高效性的同时,实现了考试系统中信息传输的安全性,而且无须其他额外的软硬件开销。     

Survey of the Internet of things operating system security

With the rapid popularization and wide application of the Internet of things (IoT),the security problems of IoT operating system,which is the essential part,become more and more urgent.Firstly,the famous IoT operating systems and their different features were introduced,then it was compared with present embedded systems.Secondly,On the basis of the survey of research related to IoT operating system,the research was discussed and analyzed from the view of building a comprehensive security system,then security challenges and opportunities which the IoT system faced were pointed out,and the research status of the security of the IoT operating system was summarized.Finally,the promising future study directions in the IoT operating system security field were discussed based on the drawbacks of the existing researches,particularly,the IoT system survival technology as a new research direction was pointed out.     

硫化锌薄膜的制备和结构分析

用常规分舟热蒸发法在玻璃衬底上制备硫化锌薄膜，用X射线衍射和透射电子显微镜研究该薄膜的晶体结构，发现硫化锌薄膜与流化锌粉末在晶体结构上存在差异，实验证实硫化锌晶体是具有高于性的共价键晶体。     

多媒体技术：第三讲 多媒体的同步与传输

本文介绍了多媒体同步的概念及模型，并分析了多媒体传输对网络的要求及现存网络对多媒体通信的支撑情况。     

IR-sintering of ink-jet printed metal-nanoparticles on paper

Sintering of printed metal nanoparticles can be made not only by conventional heating, but also by, e.g., electrical, microwave, plasma, laser and flash lamp annealing. We demonstrate sintering by using low-cost incandescent lamps as an effective way of obtaining highly conductive contacts of two types of ink-jet printed metal-nanoparticle inks on paper; both alkanethiol protected gold nanoparticles and a commercially available silver nanoparticle ink. This low-cost roll-to-roll compatible sintering process is especially suitable on paper substrates because of the high diffuse reflectance, relatively high thermal stability and low thermal conductivity of paper. A volume resistivity of around 10 μΩ cm was achieved of the inkjetted silver nanoparticles within 15 s of exposure to an IR lamp, which corresponds to a conductivity of 10-20% of that of bulk silver. Too long exposure time and too high intensity, however, lead to darkening of the paper fibers. Both the crack formation and the coffee ring effect of the inkjet printed gold nanoparticles were, furthermore, found to be reduced on paper as compared to glass or plastic substrates.     

Fingerprint-based key binding/recovering scheme based on fuzzy vault

This letter proposes fingerprint-based key binding/recovering with fuzzy vault. Fingerprint minutiae data and the cryptographic key are merged together by a multivariable linear function. First, the minutiae data are bound by a set of random data through the linear function. The number of the function＇s variables is determined by the required number of matched minutiae. Then, a new key derived from the random data is used to encrypt the cryptographic key. Lastly, the binding data are protected using fuzzy vault scheme. The proposed scheme provides the system with the flexibility to use changeable number of minutiae to bind/recover the protected key and a unified method regardless of the length of the key.