Striping and Scheduling for Large Scale Multimedia Servers

When designing a multimedia server, several things must be decided: which scheduling scheme to adopt, how to allocate multimedia objects on storage devices, and the round length with which the streams will be serviced. Several problems in the designing of large-scale multimedia servers are addressed, with the following contributions: (1) a striping scheme is proposed that minimizes the number of seeks and hence maximizes the performance; (2) a simple and efficient mechanism is presented to find the optimal striping unit size as well as the optimal round length, which exploits both the characteristics of VBR streams and the situation of resources in the system; and (3) the characteristics and resource requirements of several scheduling schemes are investigated in order to obtain a clear indication as to which scheme shows the best performance in realtime multimedia servicing. Based on our analysis and experimental results, the CSCAN scheme outperforms the other schemes. It is believed that the results ar     

中间件Tuxedo在MES应用中数据传输的研究

简要介绍了流程工业MES体系结构和Tuxedo数据传输的类型,并对Tuxedo的FML缓冲格式进行了研究。根据MES业务的要求,用面 向对象的方法及相关技术,将Tuxedo的数据存取、传输和Service调用进行了封装,完成了ATMI类的实现,并在项目中成功地应用。     

基于缓冲溢出漏洞的攻击及其预防研究综述

近十几年来，由操作系统缓冲区溢出漏洞导致的攻击带来了严重的网络安全问题，它的安全危害级别相当高。如何有效地消除基于缓冲区溢出的攻击，可以消除一个相当普遍的安全隐患。本文针对缓冲区溢出漏洞的基本原理，系统分析了攻击过程，比较了不同的防御手段及其优缺点。最后介绍了综合利用现有的方法防止该攻击的发生。     

Si衬底上SrMnO3缓冲层对La0.8Sr0.2MnO3薄膜择优取向生长的影响

利用磁控溅射方法在(100)Si衬底上首先生长SrMnO3(SMO)作为缓冲层，再沉积得到了(110)择优取向生长的La08Sr02Mn03(LsMO)薄膜。利用X射线衍射仪分析了SMO缓冲层的结构特征对LSMO薄膜择优取向生长的影响。结果表明：当沉积温度为600℃时，增加缓冲层SMO的厚度，LSMO薄膜的取向性变好；当缓冲层SMO厚度为45nm时，LSMO薄膜基本具有(110)取向生长的特征。进一步的工作证实：提高沉积温度，能够显著增加SMO缓冲层的晶粒大小，并减少LSMO薄膜择优取向生长所需的缓冲层厚度；当沉积温度为800℃时，由于类退火作用的存在，厚度为10nm的SMO缓冲层就可以实现LSMO薄膜择优取向的生长。     

采用基于速率的缓存控制的CSFQ算法

在核心无状态公平队列调度(CSFQ)算法的基础上,提出了一种采用基于速率的随机早期检测(RED)机制的核心无状态公平队列调度(rr-CSFQ)算法.在路由器中根据网络拥塞状态和数据流到达速率,采用基于速率的随机早期检测机制进行缓存管理.该算法通过调节早期丢包概率,解决了CSFQ时延较长造成的缓存"丢尾"问题,提高了带宽在不同数据流之间分配的公平性.仿真实验证明,该算法在缓存较小的情况下仍能保证带宽在传输控制协议(TCP)数据流和用户数据报协议(UDP)数据流之间的公平分配.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.     

Fabrication of NiO Buffer Layer for YBCO Coated Conductors by Combining Sputtering and SOE Method

In research of YBCO coated conductors, the development of a oxide template for epitaxial growth of YBCO is very important. Matsumoto et al have demonstrated the potential of the surface oxidation epitaxial (SOE) route for formation a cube textured NiO layer on nickel tapes. The epitaxial NiO functions as a buffer layer of chemical reaction between YBCO and nickel, and as a template for the epitaxial growth of YBCO. However, the surface quality of NiO is difficult to control and defects such as crack, spall and deep grooves exist in SOE NiO layer. A new approach combining sputtering and SOE method to obtain crack-free and cube textured NiO layer were reported. Ni tapes prepared by the combination of rolling and recrystallization were used for this work. A coating of Ni was first deposited on the tapes via magnetron sputtering. Then on the coating tapes, continuous and textured NiO layer were achieved by SOE technology.     

生产线缓冲区容量优化配置:案例研究

生产线缓冲区容量的配置是影响系统性能指标的重要因素之一。这里采用具有阻塞的开排队网络模型研究生产线缓冲区容量的优化配置问题,编制了该模型的一种近似解法——分解算法的应用程序以及仿真程序,并结合工厂的生产实例,探讨了该生产线缓冲区的分配方案,对提高生产效益有一定的指导意义。     

Behavior and mechanism of the stress buffer effect of the inside ceramic layer to the top ceramic layer in a double-ceramic-layer thermal barrier coating

The Double-Ceramic-Layer Thermal Barrier Coating (DCL-TBC) consists of a top ceramic layer (TC1), an inside ceramic layer (TC2), bond coat (BC) and alloy substrate. The top ceramic layer is made by new ceramic materials which has the lower thermal conductivity, such as LZ, LZ₇C₃, LMA etc. Although these materials have good high temperature performance and thermal insulation properties, their thermal expansion coefficients are very low which cause higher degree of mismatch with material properties of alloy substrate.     

Making renewable energy competitive in India: Reducing financing costs via a government-sponsored hedging facility

In India, a significant barrier to market-competitiveness of renewable energy is a shortage of attractive debt. Domestic debt has high cost, short tenors, and variable interest rates, adding 30% to the cost of renewable energy compared to renewable energy projects elsewhere. Foreign debt is as expensive as domestic debt because it requires costly market-based currency hedging solutions. We investigate a government-sponsored foreign exchange facility as an alternative to reducing hedging costs. Using the geometric Brownian motion (GBM)² as a representative stochastic model of the INR–USD foreign exchange rate, we find that the expected cost of providing a currency hedge via this facility is 3.5 percentage points, 50% lower than market. This leads to an up to 9% reduction in the per unit cost of renewable energy. However, this requires the government to manage the risks related to unexpected currency movements appropriately. One option to manage these risks is via a capital buffer; for the facility to obtain India's sovereign rating, the capital buffer would need to be almost 30% of the underlying loan. Our findings have significant policy implications given that the Indian government can use this facility to make renewable energy more competitive and, therefore, hasten its deployment.