技能点组合分布的技能操作题库组卷研究①

根据技能组卷特点提出围绕技能点构建组卷约束模型,使用组合分布策略实现技能题库自动组卷。设计了技能点组卷矩阵约束模型,重点探讨组合分布组卷策略实现的三个关键环节：参数验证优化、技能点组合方案生成和技能试卷生成。通过实例验证表明：使用该方法实现技能题库组卷完全满足技能点组卷矩阵约束条件,具有组卷方法简便、组卷效率高、试卷质量优的特点,非常适合技能题库的组卷应用。     

基于VB的风力机叶片外形优化设计

为了实现风力发电机风轮叶片外形的优化设计,以风场风速分布为基础提出了综合优化目标;以片条理论为基础提出了以展弦比为关键参数的修形约束条件的气动优化目标,建立了叶片外形优化设计的数学模型。采用枚举法和循环结构,选用Access数据库,应用Visual Basic编制程序实现叶片外形的优化设计。针对内蒙古某地区设计了1.5MW风力机叶片,与国外同功率某通用叶片进行了对比分析。结果表明,两种叶片外形基本吻合,而且文中设计的叶片在性能上有明显优势,同时也验证了文中提出数学模型的可靠性和程序的实用性。     

粒子群优化算法在桁架结构优化中的应用

介绍了粒子群优化（PSO）算法的一种改进算法：用于约束优化问题的启发式粒子群优化（HPSO）算法。针对HP-SO算法在桁架结构优化中速度较慢的问题,将HPSO算法的约束处理策略与另一种适用于粒子群算法的约束处理方法结合,并将改进后的算法应用到1个桁架结构截面优化设计算例中,同时与HPSO算法进行对比分析。对于此算例,改进算法和HPSO算法都运行了多次,从多次运行的统计分析中可以看出,改进算法的优化效果和稳定性好于HPSO算法,且结构分析的次数减少了一半左右,从而整个程序运行的速度比HPSO算法提高了将近一倍。     

Adding cardinality constraints to integer programs with applications to maximum satisfiability

Max-SAT-CC is the following optimization problem: Given a formula in CNF and a bound k, find an assignment with at most k variables being set to true that maximizes the number of satisfied clauses among all such assignments. If each clause is restricted to have at most ? literals, we obtain the problem Max-?SAT-CC. Sviridenko [Algorithmica 30 (3) (2001) 398-405] designed a (1−e⁻¹)-approximation algorithm for Max-SAT-CC. This result is tight unless P=NP [U. Feige, J. ACM 45 (4) (1998) 634-652]. Sviridenko asked if it is possible to achieve a better approximation ratio in the case of Max-?SAT-CC. We answer this question in the affirmative by presenting a randomized approximation algorithm whose approximation ratio is . To do this, we develop a general technique for adding a cardinality constraint to certain integer programs. Our algorithm can be derandomized using pairwise independent random variables with small probability space.     

Adaptive output feedback tracking control of robot manipulators using position measurements only

In this paper, a new adaptive neuro controller for trajectory tracking is developed for robot manipulators without velocity measurements, taking into account the actuator constraints. The controller is based on structural knowledge of the dynamics of the robot and measurements of joint positions only. The system uncertainty, which may include payload variation, unknown nonlinearities and torque disturbances is estimated by a Chebyshev neural network (CNN). The adaptive controller represents an amalgamation of a filtering technique to generate pseudo filtered tracking error signals (for the elimination of velocity measurements) and the theory of function approximation using CNN. The proposed controller ensures the local asymptotic stability and the convergence of the position error to zero. The proposed controller is robust not only to structured uncertainty such as payload variation but also to unstructured one such as disturbances. Moreover the computational complexity of the proposed controller is reduced as compared to the multilayered neural network controller. The validity of the control scheme is shown by simulation results of a two-link robot manipulator. Simulation results are also provided to compare the proposed controller with a controller where velocity is estimated by finite difference methods using position measurements only.     

城域以太网浅析

主要介绍了城域以太网技术的发展过程及其优缺点,对常见的技术方案和当前制约城域以太网发展的因素做了进一步分析。     

AutoSyn: A new approach to automated synthesis of composite web services with correctness guarantee

How to compose existing web services automatically and to guarantee the correctness of the design(e.g. freeness of deadlock and unspecified reception,and temporal constraints) is an important and challenging problem in web services. Most existing approaches require a detailed specification of the desired behaviors of a composite service beforehand and then perform certain formal verification to guarantee the correctness of the design,which makes the composition process both complex and time-consuming. In th...     

不确定系统D稳定与方差约束的鲁棒H∞可靠控制

研究了一类不确定系统区域稳定和方差约束的鲁棒H∞可靠控制器的设计方法,其目的是通过设计状态反馈控制器,使闭环系统的极点被配置在给定的圆盘中,同时,当有外生扰动,以及所有可能的不确定及其敏感执行器失效的时候,依然能满足闭环传递函数H∞范数有界和稳态方差的约束.借助于LMI和凸优化技术,给出了控制器存在的充分条件及其解析式.最后,通过一个仿真例子,说明该方法的可行性.     

Automated processing for map generalization using web services

In map generalization various operators are applied to the features of a map in order to maintain and improve the legibility of the map after the scale has been changed. These operators must be applied in the proper sequence and the quality of the results must be continuously evaluated. Cartographic constraints can be used to define the conditions that have to be met in order to make a map legible and compliant to the user needs. The combinatorial optimization approaches shown in this paper use cartographic constraints to control and restrict the selection and application of a variety of different independent generalization operators into an optimal sequence. Different optimization techniques including hill climbing, simulated annealing and genetic deep search are presented and evaluated experimentally by the example of the generalization of buildings in blocks. All algorithms used in this paper have been implemented in a web services framework. This allows the use of distributed and parallel processing in order to speed up the search for optimized generalization operator sequences.

A classification of methods for distributed system optimization based on formulation structure

Augmented Lagrangian coordination (ALC) is a provably convergent coordination method for multidisciplinary design optimization (MDO) that is able to treat both linking variables and linking functions (i.e. system-wide objectives and constraints). Contrary to quasi-separable problems with only linking variables, the presence of linking functions may hinder the parallel solution of subproblems and the use of the efficient alternating directions method of multipliers. We show that this unfortunate situation is not the case for MDO problems with block-separable linking constraints. We derive a centralized formulation of ALC for block-separable constraints, which does allow parallel solution of subproblems. Similarly, we derive a distributed coordination variant for which subproblems cannot be solved in parallel, but that still enables the use of the alternating direction method of multipliers. The approach can also be used for other existing MDO coordination strategies such that they can include block-separable linking constraints. This work is funded by MicroNed, grant number 10005898.