Modeling video sources for real-time scheduling

What is the impact of the autocorrelation of variable-bit-rate (VBR) sources on real-time scheduling algorithms? Our results show that the impact of long term, or interframe, autocorrelation is negligible, while the impact of short term, or intraframe, autocorrelation can be significant. Such results are essentially independent of the video coding scheme employed. To derive these results, video sequences are modeled as a collection of stationary subsequences called scenes. Within a scene, a statistical model is derived for both the sequence of frames and of slices. The model captures the distribution and the autocorrelation function of real-time video data. In previous work, the pseudoperiodicity of the slice level auto-correlation function made it difficult to develop a simple yet accurate model. We present a generalization of previous methods that can easily capture this pseudoperiodicity and is suited for modeling a greater variety of autocorrelation functions. By simply tuning a few parameters, the model reproduces the statistic behavior of sources with different types and levels of correlation on both the frame and the slice level.     

Nonlinear adaptive algorithms for equalisation in mobile satellite communications

This paper considers the equalisation problem in Quadrature Phase-Shift Keying (QPSK) modulated signals which have been distorted by the passage through a transmission channel. The channel is modelled as a Rician fading channel to simulate the behaviour of the transmission channel in the mobile satellite context. The equalisation is treated as the generalisation of the channel behaviour, and some algorithms with the structure of an artificial neural network using the Multilayer Perceptron, Volterra Series and Radial Basis Function are described. Results for the BER performance of typical transversal equalisers, with Square-Root Kalman adaptation algorithm, and algorithms with artificial neural network structure are also reported and evaluated. Improved performance is exhibited by the artificial neural network approaches.     

RAID的存储信道分析

本文从冗余磁盘阵列的信道模型出发，研究各部分组成的理论与技术。文中在给出系统的模型描述之后，着重分析了冗余信息元生与检纠错、数据分割与同步。还研究了系统中的负荷平衡问题，指出了磁盘优化调度的方向。     

控制决策的信息传输

本文讨论了在一条通讯通道上执行基本控制决策的信息传输问题。结果表明当且仅当第一条通道可模拟另一条通道的操作时，则第一条通道在任何情况下比另一条通道都有优势。     

短模型上的明渠非恒定流试验

水工整体模型试验中,明渠非恒定流至今大多被简化为恒定流,而效果有时并不理想。本文指出,只要设置固定式曲线尾门,并有必要的动态量测设备,便可模拟原型非恒定流;即使模型偏短,也能得出比恒定流试验更接近原型的成果。在同一模型上,既做恒定流试验,又进行必要的非恒定流试验,二者相辅相成,必将有助于试验水平的提高。作为例证,本文介绍了泄洪调度导致航道水面波动的一项试验成果,并以岩基冲刷、通航水流条件、围堰过水、河床冲淤等研究课题为例,讨论了采用“短模型非恒定流试验方式”的必要性与可行性。     

千兆比以太网技术

千兆比以太网是一种新型高速局域网，它一方面兼容传统以太网的主要标准结构，保护了用户先前的投资和系统配置，并使系统升级方便，以较实际的价格赢得了支持的发展。另一方面，它又采纳了光纤通道的低层协议以及其他一些在行兆比速率下应作的改进，使它获得了高速宽带性能。本文还列举了从快速以太网和ＦＤＤＩ向千兆比以太网迁移的网络配置策略。     

峒室爆破CAD设计方法研究

本文对峒室爆破断面布药计算机辅助设计参数驱动方法进行了探讨围绕断面布药主要参数的变化，提出一种基于参数驱动的计算机辅助设计方法，利用ｗｉｎｄｏｗｓ操作系统下的动态数据交换特性，对断面布药进行布药参数优化，实现了交互调整布药，形成一套断面布的计算机软件，为工程爆破设计实现计算机提供了一种可行的方法。     

Melt index prediction by weighted least squares support vector machines

Melt index is considered an important quality variable determining product specifications. Reliable prediction of melt index (MI) is crucial in quality control of practical propylene polymerization processes. In this paper a least squares support vector machines (LS‐SVM) soft‐sensor model of propylene polymerization process is developed to infer the MI of polypropylene from other process variables. Considering the use of a SSE cost function without regularization might lead to less robust estimates; the weighted least squares support vector machines (weighted LS‐SVM) approach of propylene polymerization process is further proposed to obtain a robust estimation of melt index. The performance of standard SVM model is taken as a basis of comparison. A detailed comparison research among the standard SVM, LS‐SVM, and weighted LS‐SVM models is carried out. The research results confirm the effectiveness of the presented methods. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 285–289, 2006     

Hydrocarbon exploration risk evaluation through uncertainty and sensitivity analyses techniques

The evaluation of the exploration risk in the oil industry is a fundamental component of the decision process related to the exploratory phase. In this paper the two basic components of the exploratory risk: trap geometry and trapped hydrocarbon quantities (fluid), are compounded in a single coherent uncertainty and sensitivity approach. The results clarify that the model geometry influences each Petroleum System Modeling step and that the geometric uncertainty is correlated with the fluid uncertainty. The geometric uncertainty evaluation makes use of geostatistical techniques that produce a number of possible realizations of the trap geometry, all compatible with available data. The evaluation of the fluid uncertainty, through a Monte Carlo methodology, allows us to compute the possible quantities of oil and gas, generated in a basin and migrated from the hydrocarbon source location to each single trap. The final result is the probability distribution of oil and gas for each trap in the basin, together with other useful indicators like: the hydrocarbon filling probability map, the closure probability map, the drainage area probability map, the spilling paths probabilities, the trap-filling scenarios.