Using NetFlow/IPFIX for Network Management

To exchange experiences with, and to discuss ideas on the usage of NetFlow/IPFIX in network management, the IRTF/NMRG, together with the European EMANICS Network of Excellence, organized a one-day workshop in October 2008. This paper presents a report of that meeting.     

Report of the Third Workshop on the Usage of NetFlow/IPFIX in Network Management

The Network Management Research Group (NMRG) organized in 2010 the Third Workshop on the Usage of NetFlow/IPFIX in Network Management, as part of the 78th IETF Meeting in Maastricht. Yearly organized since 2007, the workshop is an opportunity for people from both academia and industry to discuss the latest developments of the protocol, possibilities for new applications, and practical experiences. This report summarizes the presentations and the main conclusions of the workshop.     

网络管理的研究和发展

网络管理理念，模型和产品的研究和开发与计算机和通信网络相关学科的发展有着紧密联系，分布和智能的网络管理是必然趋势，目前的体系结构需要集成，Web,Java分布对象以及多Agent系统等关键技术，但是通过对现有网络管理标准和系统的分析发现，当前亟需探索和解决的是信息模型问题，DMTF提出的CIM模型和IRTF提出的SMIng是重要的方向，它们都能映射为语法简洁和语义丰富XML模块，借助W3C提出RDF建立网络管理知识模型成为可能，并已经应用在多Agent网络管理原型系统中。     

Kademlia based routing on locator-ID separated networks for new generation networks

We propose an efficient ID-based routing method using Kademlia on Locator-ID separated networks for New Generation Networks. Due to the increase in Internet traffic, many people pointed out problems of the Internet. Therefore, studies on New Generation Networks by clean-slate approach are hot topics. New Generation Network discussions include locator-ID separation for resolving the problems of routing tables and mobility support. IETF and IRTF proposed some protocols for Locator-ID separation, but they have problems in Name servers for Locator-ID mapping resolutions. Therefore, we propose a method for communicating specified ID hosts using hierarchical Kademlia without resolving Locator-ID mapping explicitly. Our method does not need Name servers of Locator-ID mappings. We can also support host mobility by updating Kademlia links, and hierarchical Kademlia achieves efficient routings considering physical distances. We discuss the communication delay and size of routing tables of our proposed method, and also show the effectiveness of hierarchical Kademlia through simulation experiments.     

Error- and loss-tolerant bundle fragment authentication for space DTNs

To ensure the authenticity and integrity of bundles, the in-transit PDUs of bundle protocol (BP) in space delay/disruption-tolerant networks (DTNs), the bundle security protocol specification (IRTF RFC6257) suggested using a digital signature directly over each bundle. However, when bundle fragment services are needed, this mechanism suffers from heavy computational costs, bandwidth overheads and energy consumption. In this paper, we address the fragment authentication issue for BP by exploiting the combination of RS error correction and erasure codes with the help of batch transmission characteristic of DTNs. The RS error correction and erasure codes are adopted to allow the receivers to locate the false/injected fragments and reconstruct the only one signature shared by all fragments of a bundle, even if some other fragments are lost or routed to a different path. Getting only partial authentic fragments, a DTN node is able to detect and filter the false/injected fragments, and authenticate the origin of a bundle as well. Such an approach tolerates high delays, unexpected link disruption and the BP nature of routing fragments of the same bundle possibly via different paths. The performance analysis demonstrates that both of our schemes, which follow our generic idea based on RS codes, significantly reduce bandwidth overheads and computational costs as compared to the prior works.     

一种提高稳定性和公平性的主动队列管理机制

结合平均队列和负载衡量拥塞,实现选择性丢包,提出早期选择性丢包算法(ESD)．ESD采用指数函数计算丢包概率,使丢包概率随拥塞程度增大而指数递增;引入记录活跃连接状态信息的虚队列,并在虚队列上假轮转,以检测发送速率大的连接;区分非响应性连接和响应性连接,挑选丢包的候选连接,拥塞时优先丢弃候选连接在队列头部的数据包．实验结果表明,ESD可提高队列稳定性,降低Web流和RTT较大连接的丢包率,提高连接占用带宽的公平性,缩短应用响应时间．     

基于多时相TM和北京一号卫星影像的春播进度遥感监测

基于作物生长的物候规律,利用2007年4月26日、2007年5月28日Landsat TM影像和2007年6月28日北京一号卫星影像进行北京地区春播进度遥感监测。首先,分析了地物类型之间的光谱可分性距离;其次,采用逐步鉴别分析方法,并将掩膜技术和决策树分类方法相结合,监测北京2007年5月28日和6月28日的春播作物种植面积;最后,基于地面调查点对分类结果进行精度评价。结果表明5月28日总体精度为84.5%,6月28日总体精度为88.0%;逐步鉴别分析方法有利于寻找作物分类的光谱差异,建立多时相分类规则,简化了多时相多作物遥感分类流程并提高了分类精度。     

Synergy in the Summertime

Impressions from the First International Conference on Creative Thinking, University of Malta, July 26th, 27th, 1993, and the Fourth European Conference on Creativity and Innovation, Darmstadt, Germany, August 25th–28th, 1993.     

Physical workload in neck, shoulders and wrists/hands in dental hygienists during a work-day

Physical workload was recorded by electromyography, inclinometry and goniometry for twelve female dental hygienists during authentic work. Their work was, in relation to other types of work, characterised by pronounced head flexion (90th percentile 46°), high loads on the forearm extensor muscles (90th percentile 23% and 18% of maximal EMG (MVE), for the right and left sides, respectively), average loads on trapezius muscles (90th percentile 15% and 14% MVE), average arm elevation (99th percentile 83° and 72°) and average wrist flexion and velocities (50th percentiles 17° of extension and 7.3°/s, for the right side). Manual scaling and machinery (use of ultrasonic scaling and hand-pieces) showed higher loads on the trapezius muscles, regarding muscular rest, as well as the 10th and 50th percentiles, than the other tasks, and for the forearm extensor muscles, an almost complete lack of muscular rest (0.1% time), and much higher loads regarding the 10th and 50th percentiles. Further, more pronounced head flexion and lower head and upper arm velocities were found, indicating more constrained postures for the neck and shoulders for the manual scaling and machinery. Use of ultrasonic scaler reduced the 50th percentile loads on the right forearm extensor muscles, but had no effect on the fraction of muscular rest and on the 10th percentile load. These findings are consistent with the high prevalences of musculoskeletal disorders among dental hygienists.     

Test Technology TC Newsletter

This month's Test Technology TC Newsletter reviews the July 2009 2nd IEEE Workshop on Hardware-Oriented Security and Trust, and features upcoming events for November 2009: 40th International Test Conference, 18th Asian Test Symposium, and 10th IEEE Workshop on RTL and High-Level Testing.     

基于AVHRR和MODIS数据的全球植被物候比较分析

AVHRR和MODIS卫星数据在全球和区域尺度植物物候对气候变化响应研究中起着重要的作用,然而两种传感器在全球尺度物候监测的一致性有待验证。首先利用时间序列谐波分析法(HANTS)对2005年全球GIMMS AVHRR NDVI和MODIS 13A2 数据进行滤波处理;然后基于改进的动态阈值方法,提取全球植被的返青期(SOS)、枯黄期(EOS)和生长季长度(DOS);最后分区域比较和评估两种传感器提取物候参数的潜力。研究结果表明：2005年全球大部分地区植被在第100～140 d开始生长,到第260～300 d逐渐停止生长,生长季长度集中在130～180 d,并且和区域研究结果具有一致性;两种传感器提取的植被关键物候期的空间变化趋势是一致的,随着纬度升高,返青期呈现推迟趋势,枯黄期呈现提早趋势,生长季长度呈现缩短趋势;AVHRR和MODIS提取落叶林和草地的SOS、EOS和DOS在欧亚大陆和北美洲区域的相关系数大部分达到0.9以上。     

Effects of BMI and task parameters on joint angles during simulated small parts assembly

Functional limitations of persons classified into different obesity categories were evaluated while performing a simulated small parts assembly tasks. Joint angles (measured using electro-goniometers) and maximum forward function reach (MFFR) were used to quantify function limitations, and tasks were completed on three workstations designed for the 5th, 50th, and 95th percentile workers based on anthropometric data tables. Results revealed that BMI category did not significantly affect measured joint angles. Results also indicated that joint angles when working at the 95th percentile workstation configuration were significantly larger than those measured at the 5th percentile workstation configuration. Further, obese class 2 and obese class 3 groups MFFRs were significantly shorter than the normal weight group, which was expected. These results imply that workstation design considerations should include obesity levels, and that work should be placed near the worker and should be elevated to reduce pressure on joint angles while working for larger (obese) individuals.     

Too much computer and Internet use is bad for your grades, especially if you are young and poor: Results from the 2001 Brazilian SAEB

This work presents the analysis of the 2001 Brazilian Basic Education Evaluation System (SAEB) achievement exam. The SAEB tested 4th, 8th, and 11th grade students, in mathematics and reading (Portuguese). We classified the students into seven socioeconomic classes, and for each class, compared the test results according to frequency of computer use, computer ownership, Internet access at home, and whether the teachers used computers and Internet as pedagogical tools. Frequency of computer use had, in general, a negative effect on the test results, and the negative effect increased for younger and poorer students. Computer ownership had, in general, a small positive effect on the test results for older students, and no effect for 4th graders. Internet access had a negative effect for younger and poorer students, and a positive effect for 11th graders. Finally, whether the teacher used computers or Internet as pedagogical tools had no effect on the student’s test results for all social economic classes and grades.     

Too much computer and Internet use is bad for your grades,especially if you are young and poor: Results from the 2001 Brazilian SAEB

This work presents the analysis of the 2001 Brazilian Basic Education Evaluation System (SAEB) achievement exam. The SAEB tested 4th, 8th, and 11th grade students, in mathematics and reading (Portuguese). We classified the students into seven socioeconomic classes, and for each class, compared the test results according to frequency of computer use, computer ownership, Internet access at home, and whether the teachers used computers and Internet as pedagogical tools. Frequency of computer use had, in general, a negative effect on the test results, and the negative effect increased for younger and poorer students. Computer ownership had, in general, a small positive effect on the test results for older students, and no effect for 4th graders. Internet access had a negative effect for younger and poorer students, and a positive effect for 11th graders. Finally, whether the teacher used computers or Internet as pedagogical tools had no effect on the student’s test results for all social economic classes and grades.     

Effects of BMI and task parameters on postural sway during simulated small parts assembly

Postural stability is critical for ensuring a safe workplace. Employees with poor stability are more prone to falls and injuries while at work. In this study, postural sway of participants in different obesity categories was evaluated while performing an assembly workstation task. The study included three workstations: those designed for the 5th, 50th and 95th percentile workers based on anthropometric data tables. Force plates were used to study the differences in postural sway in both the medial–lateral and anterior–posterior directions. The results revealed that the obese class 1 and obese class 2 groups’ anterior–posterior sway was significantly larger than that of the normal weight groups while performing assembly work tasks. Also, pace type (self-paced or time-paced) and workstation (5th, 50th and 95th percentile) significantly affected the postural sway. The postural sway was not affected by gender differences. Workstations should be designed to accommodate the increased postural sway of obese workers.     

A literary lexicography project for the Italian language

CLIPON is an acronym for Concordanze della Lingua Italiana Poetica dell'Otto/Novecento. The aim of the project described here is to produce lexicons and lemmatized concordances of the literary Italian language of the nineteenth and twentieth centuries. The corpus involves groups of mainly poetic works and authors that have a common denominator as regards schools, currents, culture and chronology.Giuseppe Savoca, professor of modern and contemporary Italian literature at the University of Catania, is president of Italy's Scientific Coordinating Commission for the Italian National Research Council, and directs the CLIPON project. A literary critic, with a background in linguistics and psychoanalysis, he has published widely on 18th, 19th, 20th century Italian authors. More than a decade ago he devised and introduced computer applications for integral concordance editing, thus starting the largest literary project in lexicography for 19th and 20th century poetry.     

第四方物流中决策支持及物流方案的优化

在简单介绍概念的基础上，基于具体项日应用背景，提出了第四方物流运作中决策支持系统的框架。对其中的优化问题提出了赋予多维权的有向图模型，并就所选的模型，介绍了在实际应用中基于搜索的求解方法。     

MIMO双线性系统稳定性研究的新方法

基于Volterra级数理论,计算出MIMO双线性系统的n阶冲激响应函数矩阵(或n阶 Volterra核矩阵).通过研究它的n阶冲激响应函数矩阵的性质,给出了一些简单的开环稳定性 判据;并深入研究了它们的闭环稳定性,给出了直接利用其子系统的开环稳定性来判别其闭环 系统稳定性的判据;最后,用仿真实例来验证其有效性.     

Calf massager: Intervention for body muscle discomfort during prolonged standing

Many occupations require workers to stand for long periods of time without proper interventions, which causes discomfort in the back and lower limbs. Therefore, this study aims to assess the effectiveness in alleviating body muscle discomfort during prolonged standing through the use of a calf massager. This study was conducted among male workers at a manufacturer with production line workers and the list was obtained from the HR Department and simple random sampling was done by number categorization. A total of 100 respondents (50 respondents for both the control and the experimental groups) participated in this study. The experiment took place in a room with a similar setup for the production line. Each respondent was requested to perform the simulated task for 2 hr. For the experimental group, the calf massager was turned on every 15 min. At every 15‐min interval after turning on the calf massager, respondents from both groups were required to evaluate their discomfort level on a Borg's scale CR‐10 questionnaire. The results showed that the level of body discomfort among respondents in the experimental group reduced (20–30%) compared with that of the control group. Multivariate analysis results revealed that the discomfort rating for the lower back, knees, thighs, calves, and feet was significantly lower (p < .05) among the experimental group compared with the control group. For lower body parts, the lower back region was statistically significant (p < .05) at the 90th, 105th, and 120th min; the thigh region was statistically significant (p < .05) at the 120th min; the knee region was statistically significant (p < .05) at the 105th and 120th min; the calf region was statistically significant (p < .05) at all minute intervals except the 15th and 45th min, while the feet region, was statistically significant at the 105th and 120th min. Therefore, this study indicates that calf massage treatment is capable of reducing body muscle discomfort during prolonged standing and highlights the significance of calf massage.     

扫描电子显微镜及能谱分析技术在黄土微结构研究上的应用

我国利用扫描电子显微镜研究黄土微结构的报道始于20世纪的70年代。随着当代电子技术和计算机的发展,利用扫描电子显微镜和能谱分析技术,可以在观测微结构的同时,实现对微结构元素分析的目的。本研究介绍了扫描电子显微镜和能谱分析技术的原理,并从样品制作、处理、观察和结果分析等角度就二者在黄土微结构研究上的应用做了探讨。