Slack-nibbling battery-aware task scheduling

Dynamic voltage scaling (DVS) is an efficient approach to maximize the battery life of portable devices. A novel overall planning strategy (OPS II) balancing slack supply and demand for DVS is proposed. An OPS II-based slack-nibbling overall planning strategy (SNOPS) algorithm is also proposed, which iteratively nibbles slacks for appropriate tasks selected by an overall planning dynamic priority function to perform DVS until the slack is exhausted and an optimum voltage setting is obtained. For a high-load task set, SNOPS manages to recover battery overload while maintaining schedulability. For random variable-load task sets, SNOPS achieves a saving of 29.51% battery capacity on average, the suboptimal gap is 27.84% narrower than that of our previously proposed OPS-based algorithm, and 92.10% narrower than that of the algorithm proposed by Chowdhury et al. Results indicate that OPS II manages to save battery to various extents while maintaining schedulability, and demonstrates good load compatibility and close-to-optimal performance on average. Biography: GAO Xun(1981–), male, Ph.D. candidate, research direction: embedded system, power optimization.     

帧存储器容量受限条件下编码视频码率变换的研究

提出了一种帧存储器容量受限条件下编码视频码率变换结构。在这种结构中，将压缩的参考图像存入帧存储器中以节省存储空间，同时通过截除适量与高频ＤＣＴ系数对应的码字以适应任意容量的帧存储器，而运动补偿直接在ＤＣＴ域实现，避免频域怀空间域转换所需的运算量，这种结构的性能随配置帧存储器容量的增加呈单调递增的关系，为存储器容量受限的情况下获得满意的变换图像质量提供了有效途径。     

Optimum Design of Laminates with Aooroximate Fully Isotrooic Behaviors

The paper presents an efficient stiffness optimization approach to fully isotropic laminates with approximate isotropic behaviors respect toboth extensional and bending stiffnesses. Based on the Integral global minimization method, the layer orientation angles andthe layer thickness ratios are chosen as design variablesand the lamination parameters are minimized to get theopthnal designs. Example of laminate with approximatefully isotropic behaviors is presented, which has lessthan one-third the number of plies of a fully isotropiclaminate.     

比喻艺术纵横谈

比喻运用范围之广,效果之妙,在修辞教学中尚未引起足够重视。本文力图通过对比喻在中学教材中的运用艺术探究,从比喻运用的特点、技法、功用等七个方面一展其艺术风采。     

遗传算法的改进及其在电机全局优化中的应用

在描述遗传算法（ＧＡ）过程的基础上，指出了遗传算法所存在的缺点，并提出了改进措施．算例表明，按照文中提出的改进思路进行优化，效果是明显的，成本得到更进一步的下降，运算时间大为缩短．     

Advances in the study of hybrid finite elements

Some new concepts and research progress in hybrid finite elements advanced in recent years are in troduced. On the basis of incompatible energy consistency analysis, the optimal condition of hybrid elements is derived and the formulation for fulfilling this condition is given. A post-processing penalty equilibrium optimization technique of hybrid element is presented to create high quality hybrid model. For incompressible problems, a method of deviatoric hybrid element is proposed and unification of computation between compressible and incompressible media is achieved.     

城市交通组织优化仿真模型的参数估计新方法

从逼近性较好和易于计算机实现两个角度,对城市交通组织优化仿真模型中参数估计方法进行了研究,给出了极大似然估计法、范数理论的数据拟合以及三次B样条拟合方法,并对3种方法的特点和适用条件进行了比较。极大似然估计法基于数理统计理论,建立在已有试验数据基础上,适合于精度要求不高的情况;范数理论的数据拟合采用欧氏范数(1-范数,2-范数,无穷范数)作为误差量度的准则,理论严密,有明确的几何意义,适合于拟合函数曲线特征比较明显的情况;数据分布规律不明显时,采用三次B样条函数拟合。实例表明,3种仿真模型参数估计方法均是可行的,平均绝对误差从小到大依次为三次B样条拟合方法、2-范数拟合方法和极大似然估计法,分别为0.002 80、.016 90、.017 1。在实际工程中,应分别采用3种方法进行估计,选择误差较小的方法。     

用不等式求解一类非线性规划问题

本文在 Bellman 提出的最优化原理的理论基础上,以几种常用的不等式为工具,解一类具有递归型式的非线性规划问题。此法回避了解析法中多维分析的复杂性,使问题得到简化。     

工业企业材料订货优化决策支持系统研究

在工业企业的产品成本中,材料成本占据着相当大的比重。如何根据生产需要对材料的订货批量、订货批次及订货周期进行决策,将影响到企业的产品成本和经济效益。这里对运用计算机的特有功能,结合材料存储优化决策原理和模型建立的订货优化决策支持系统的原理和应用进行了阐述。     

工业过程稳态优化中的PID型迭代学习控制

给出一种PID型迭代学习算法．对工业过程稳态优化中的动态施行迭代学习控制，加快了动态响应，提高了控制效果．从理论上分析了算法的收敛性，并给出数字仿真结果．