High-performance implementation of in-network traffic pacing for small-buffer networks

Demands on data communication networks continue to drive the need for increasingly faster link speeds. Optical packet switching networks promise to provide data rates that are sufficiently high to satisfy the needs of the future Internet core network. However, a key technological problem with optical packet switching is the very small size of packet buffers that can be implemented in the optical domain. Existing protocols, for example the widely used Transmission Control Protocol (TCP), do not perform well in such small-buffer networks. To address this problem, we have proposed techniques for actively pacing traffic at edge networks to ensure that traffic bursts are reduced or eliminated and thus do not cause packet losses in routers with small buffers. We have also shown that this traffic pacing can improve the performance of conventional networks that use small buffers (e.g., to reduce the cost of buffer memory on routers). A key challenge in this context is to develop systems that can perform such packet pacing efficiently and at high data rates. In this paper, we present the design and prototype of a hardware implementation of our packet pacing technique. We discuss and evaluate design trade-offs and present performance results from an prototype implementation based on a NetFPGA fieldprogrammable gate array system. Our results show that traffic pacing can be implemented with few hardware resources and without reducing system throughput. Therefore, we believe that traffic pacing can be deployed widely to improve the operation of current and future networks.     

Enhancing personal communication with spatial haptics: Two scenario-based experiments on gestural interaction

Haptic gestures and sensations through the sense of touch are currently unavailable in remote communication. There are two main reasons for this: good quality haptic technology has not been widely available and knowledge on the use of this technology is limited. To address these challenges, we studied how users would like to, and managed to create spatial haptic information by gesturing. Two separate scenario-based experiments were carried out: an observation study without technological limitations, and a study on gesturing with a functional prototype with haptic actuators. The first study found three different use strategies for the device. The most common gestures were shaking, smoothing and tapping. Multimodality was requested to create the context for the communication and to aid the interpretation of haptic stimuli. The second study showed that users were able to utilize spatiality in haptic messages (e.g., forward–backward gesture for agreement). However, challenges remain in presenting more complex information via remote haptic communication. The results give guidance for communication activities that are usable in spatial haptic communication, and how to make it possible to enable this form of communication in reality.     

Analysis of the thermal behaviour of a low cost,single-family,more sustainable house in Porto Alegre,Brazil

Efforts have been made in Brazil to improve the thermal performance of low-cost buildings. Since 1997 studies on low-cost housing have been developed by Núcleo Orientado para a Inovação da Edificação, the construction sector of the Engineering College of the Rio Grande do Sul University, Brazil. In 2000 a prototype of a low-cost house was built on the university campus. This prototype has undergone several evaluations in an attempt to assess its thermal and environmental performance, like: energy consumption, rainwater harvesting, use of sustainably managed wood for window frames and doors, besides a detailed accounting of overall costs. The thermal performance of the house was monitored, by recording outdoor and indoor air temperatures and relative humidity, over the period of whole year. A brief appraisal of such results, as well as the annual heating and cooling degree-hours are presented. Daily swings in outdoor are a common climatic event in Porto Alegre and the building response to daily temperature swings, greater than 10 K, and hot and cold spells are presented. The results show that the thermal performance of the prototype is fairly satisfactory, considering the limitations of a low-cost house, when artificial heating and cooling is not affordable.     

SCARA机械手的轨迹规划及运动学分析

针对药品包装机(DPP-400铝塑平板泡罩机)上使用的SCARA机械手进行轨迹规划,使用运动学逆解求出目标点处各关节的变化量,采用五次多项式插值的关节空间规划法对机械手进行轨迹规划,并结合MATLAB软件的ROOT工具箱建立机械手的三维模型,通过仿真得到位移、速度和加速度3个光滑连续运动曲线;然后在ADAMS中建立1:1的虚拟样机简化模型,通过编写五次多项式驱动函数,仿真得到关节在X、Y、Z三个方向的光滑连续的受力曲线,最后综合分析运动曲线和受力曲线证明轨迹规划的函数满足使用要求。     

履带起重机变幅拉板载荷的非线性分析

通过悬链线理论确定了变幅拉板载荷的计算方法,借助MATLAB软件编程实现了该方法的求解,并将其非线性计算结果与履带起重机虚拟样机的仿真计算结果进行对比,验证了非线性拉板张力计算方法的正确性,为快速准确的计算拉板载荷提供了一种重要方法。     

南京农业大学金陵研究院设计

该设计从实现建筑文化价值出发，通过创作原型文化内涵的发掘与利用，进行了文化价值的再创造的积极尝试。     

大坳混凝土面板堆石坝工程设计及技术特点

大坳混凝土面板堆石坝最大坝高90．2m，利用软岩料填筑大坝主体，现成功运行，全面介绍了大坝体形、面板、趾板、分缝止水、基础处理、原型观测等方面的设计特点。     

从神话时空观念的符号化管窥早期中国建筑文字 “形—意”同构

符号学的跨学科研究动态使建筑符号 的“形—意”本原研究或可从早期人类以原始 神话思维为起点建立的“宇宙生成模型和时空 观念”出发进行源流推演性解读,找寻一种根 植于人类文化符号系统“形—意”同构的原型性 解释。本文从梳理形式符号原型研究的理论范 式出发,以甲骨文、金文出现的建筑类文字“宅、 空、室、楹、阑、坛、台”等为研究对象,以象形 文字字形特征的普遍解读方式结合建筑学本体 思考,阐释早期中国建筑在类型、形态上的发展 以及建筑符号象征表意功能传承实现的过程。 管窥建筑作为中国古代“崇天—通天”时空观念 象征符号的“能指与所指”,探析我国早期建筑 类型与形态发展中的文化隐喻与象征。