Service composition for generic service graphs

Service composition is a promising approach to multimedia service provisioning, due to its ability to dynamically produce new multimedia content, and to customize the content for individual client devices. Previous research work has addressed various aspects of service composition such as composibility, QoS-awareness, and load balancing. However, most of the work has focused on applications where data flow from a single source is processed by intermediate services and then delivered to a single destination. In this paper, we address the service composition problem for multimedia services that can be modeled as directed acyclic graphs (DAGs). We formally define the problem and prove its NP hardness. We also design a heuristic algorithm to solve the problem. Our simulation results show that the algorithm is effective at finding low-cost composition solutions, and can trade off computation overhead for better results. When compared with a hop-by-hop approach for service composition, our algorithm can find composition solutions that aress 10% smaller in cost, even when the hop-by-hop approach uses exhaustive searches.     

控制反转技术分析

轻量级容器的解耦模式被称为“控制反转”或者“依赖注入”,组件之间的依赖关系由容器(运行环境)在运行期决定,从而在相当程度上降低了组件之间的耦合。该文详细论述了这种解耦模式的原理,以及依赖注入的3种主要形式,并且对几种形式进行了对比总结。     

AlSb晶体内二维磁极化子的磁场与温度效应

在考虑声子之间相互作用的同时，本文应用线性组合算符和微扰法研究了电子自旋对弱耦合二维磁极化子特性的影响。对AlSb晶体所作的数值计算结果表明，随着磁场的加强，磁极化子平均数减少；随着温度的增加，磁极化子平均数也增加；随着温度的增加，电子自旋作用以及声子之间相互作用都加强；随着磁场的加强，电子自旋作用增加而声子之间相互作用基本不变。     

浅析医药包装

随着市场经济的深入，医药包装正成为我国经济发展的朝阳产业，文中意在介绍先进的医药包装材料。分析其应用情况及发展趋势和动态。     

腐蚀磨损过程中材料的环境脆性

从腐蚀磨损的交互作用、腐蚀磨损与应力腐蚀及氢脆的异同出发，论述了磨损加速腐蚀及腐蚀加速磨损的微观机制，指出材料的环境脆性与腐蚀对磨损的加速作用程度有关．从腐蚀对磨损的加速作用、比能耗、磨痕硬度等方面分析了不锈钢 Cl^-体系、Ni-P镀层 NaOH溶液、H4340钢与Ti6A14V合金 稀硫酸溶液体系、铜合金 NH4^ (NH3)或S^2-溶液中的环境脆化行为和规律，总结出材料环境脆性的力学判据，展望了今后腐蚀磨损的研究方向．     

寒冷地区高温干燥条件下混凝土面板裂缝控制

希尼尔水库位于新疆巴音郭楞蒙古族自治州境内，气候特点为高温、干燥、冬季寒冷。根据混凝土面板产生裂缝的原因，并结合工程区的气候特点，认为控制面板的塑性收缩、干缩与冷缩裂缝是防止裂缝产生的重点。通过采用高性能混凝土，合理的养护措施(微喷灌洒水技术)，有效地防止了裂缝的产生，保证了工程质量。     

简化形式的系统EMC预测分析技术概述

本文探讨了系统级简化形式的电磁兼容性预测分析方法，该方法对于只有几对发-收干扰对的系统EMI的预测分析简洁有效，它避免了大系统间繁复的建模与大量的数据采集及其计算工作，从而对于只考虑其结果的系统间的EMC预测分析提高了效率。     

A primary study of the acoustics of Chinese traditional theatrical buildings

The traditional performing arts and theatrical buildings in China can be traced back to a long history and were well developed during Song and Yuan Dynasties, 11th-14th centuries. Pavilion stage, opened on three sides and thrusting into the audience area, was unique and the most popular form in the open-air theatres, the courtyard theatres, and the indoor theatres up to the present day. As the traditional Chinese opera is performed in an abstract way, no stage settings are required and used. Therefore, the pavilion stage including the flat or domed ceiling and the back wall is virtually functioned as a reflective shell, which increases the early reflections and also intensifies the sound in the audience area. Meanwhile, it provides sufficient self-support to the performers. Acoustical parameters including reverberation time RT, early decay time EDT, acoustic ratio C50, strength index (loudness) G, and stage support factor ST1 were measured and reported on several traditional theatrical buildings.     

盐卤除硝工艺的研究

介绍了一种采用氨碱蒸馏废液兑卤水进行除硝的新工艺 ,通过中试确定了该工艺的主要技术参数 ,为工程设计提供了条件。