直接和间接的笔倾斜输入性能对比

越来越多的笔式设备通过增加笔倾斜输入来提高其输入能力。但在直接输入设备和间接输入设备上执行笔的倾斜操作时,由于操作环境和视觉反馈的不同,往往会导致操作性能产生差异。本研究以探索笔倾斜输入在直接设备和间接设备上的性能差异为目的,以实证手段考察在两种设备上获取不同角间距下的不同笔倾斜目标时的操作速度、稳定性和准确性,讨论导致直接设备和间接设备笔倾斜性能不同的原因,并提出适用的角间距和倾斜目标位置。实验结果表明,在直接设备和间接设备上操作笔倾斜角时,在操作速度上直接设备优于间接设备,但在稳定性和准确性上,间接设备优于直接设备。20°的角间距对两种设备来说都呈现较好的性能,若需要在更小角间距内完成目标选择操作,在间接设备上的效果更好。最后,对两种设备的用户使用习惯进行了总结,为基于笔倾斜角的用户界面设计提供了帮助和参考。     

A new robust observer-based adaptive type-2 fuzzy control for a class of nonlinear systems

In this paper, a novel robust observer-based adaptive controller is presented using a proposed simplified type-2 fuzzy neural network (ST2FNN) and a new three dimensional type-2 membership function is presented. Proposed controller can be applied to the control of high-order nonlinear systems and adaptation of the consequent parameters and stability analysis are carried out using Lyapunov theorem. Moreover, a new adaptive compensator is presented to eliminate the effect of the external disturbance, unknown nonlinear functions approximation errors and sate estimation errors. In the proposed scheme, using the Lyapunov and Barbalat's theorem it is shown that the system is stable and the tracking error of the system converges to zero asymptotically. The proposed method is simulated on a flexible joint robot, two-link robot manipulator and inverted double pendulums system. Simulation results confirm that in contrast to other robust techniques, our proposed method is simple, give better performance in the presence of noise, external disturbance and uncertainties, and has less computational cost.     

Photoshop的抠图技巧分析

本文介绍了抠图的概念,分析了选区在Photoshop图像处理过程中的关键作用,提出了选区创建的直接法与间接法,具体分析了各种操作方法的优缺点及使用的广泛性。     

直接Z-型立方/六方ZnIn2S4复合光催化剂的制备及其光催化性能

通过水热反应方法制备出立方相ZnIn₂S₄和六方相ZnIn₂S₄和系列不同摩尔比的复合相ZnIn₂S₄光催化剂,使用X射线衍射、扫描电子显微镜、电子能谱、透射电子显微镜、光致发光光谱、N₂吸附-脱附法及紫外-可见光漫反射等手段表征了样品的晶体结构、显微结构及吸光特性并在可见光照射下进行了甲基橙降解实验。结果表明,复合相ZnIn₂S₄样品都具有比立方相、六方相和机械混合的ZnIn₂S₄更好的可见光催化活性,当复合相ZnIn₂S₄样品中立方相与六方相摩尔比为3:7时体系的催化活性最高。这种样品被可见光照射30 min后,甲基橙的降解率达到95.2%。其降解机理与样品较大的比表面积以及样品中的立方相与六方相之间的密切接触而形成直接Z-型光催化过程有关。     

Stable indirect adaptive interval type-2 fuzzy sliding-based control and synchronization of two different chaotic systems

An indirect approach to adaptive interval type-2 fuzzy sliding mode control is proposed for the stable synchronization of two different chaotic nonlinear systems with different initial conditions under the presence of uncertainties involving process noises and external disturbances. The indirect model-based approach to adaptation is promoted here as a more suitable strategy for the fast changes that occurs in chaotic systems. In other words, the usual direct adaptive strategies may be too slow to respond to the inherently fast changing dynamics of chaotic systems. Using Lyapunov analysis, the sliding mode approach illustrates the asymptotic convergence of synchronization error to zero as well as good robustness against external disturbances. The interval type-2 structure aims to remedy the undesirable chattering phenomenon that is common in most conventional sliding mode control applications. It also provides a more effective equivalent model in the indirect approach, which leads to improved handling of the chaotic variations and uncertainties. Two numerical pairs of chaotic systems, i.e. the Lorenz and Chen’s systems and the Rössler system and modified Chua’s circuit are considered. In particular, in comparison with its type-1 fuzzy counterpart, the control effort is reduced by an average of 26.25% and 17.4% for the synchronization of the two corresponding systems, respectively. Furthermore, the integral of squared error is also improved by an average of 27.2% and 25.33%. This is while convergence time is reduced to less than 0.5 s and 1.5 s.     

Compositional pattern producing networks: A novel abstraction of development

Natural DNA can encode complexity on an enormous scale. Researchers are attempting to achieve the same representational efficiency in computers by implementing developmental encodings, i.e. encodings that map the genotype to the phenotype through a process of growth from a small starting point to a mature form. A major challenge in in this effort is to find the right level of abstraction of biological development to capture its essential properties without introducing unnecessary inefficiencies. In this paper, a novel abstraction of natural development, called Compositional Pattern Producing Networks (CPPNs), is proposed. Unlike currently accepted abstractions such as iterative rewrite systems and cellular growth simulations, CPPNs map to the phenotype without local interaction, that is, each individual component of the phenotype is determined independently of every other component. Results produced with CPPNs through interactive evolution of two-dimensional images show that such an encoding can nevertheless produce structural motifs often attributed to more conventional developmental abstractions, suggesting that local interaction may not be essential to the desirable properties of natural encoding in the way that is usually assumed.

金属掺杂对In2O3薄膜光学性质的影响

研究了射频溅射法制备的金属／半导体类型颗粒膜的光学特性。通过样品透射谱分析，发现金属Fe的掺杂使半导体In2O3的带间跌迁由直接跃迁变为间接跃迁；随Fe所占体积份数的增加，局域态尾变宽，带隙变窄。这是由于掺入Fe颗粒后。母体材料与金属颗粒的界面处表面态增多，以及母体材料的非晶化引起的。     

基于Matlab无刷电动机模型参考自适应控制的研究与实现

本文在分析无刷电动机数学模型的基础上,建立了控制系统的仿真模型,提出了直流无刷电机调速系统模型参考自适应控制的新方法.在双闭环调速系统中,电流环采用电流滞环控制,转速环采用间接参考模型自适应控制,控制器参数估算采用最小二乘算法.仿真结果表明:这种新型的间接模型参考自适应控制方法响应快、无超调、鲁棒性强、抗干扰能力好,较传统PI控制具有更好的动、静态特性.     

The value for innovation of inter-firm networks and forming alliances: A meta-analytic model of indirect effects

In the past few decades, we have seen strong growth in the number of publications on the role of alliances and networking on innovative performance and, more generally, firm performance. The empirical results of these studies are, however, often debated, and there seems to be little consensus in the academic literature. We therefore focus our meta-analytical model test on the accumulated direction and magnitude of the indirect relationships reported in the literature between innovation, networking, alliances, and firm performance. Our meta-analysis is based on 517 correlations, 156 studies, and a total sample size of 93,048 firms. We compare the findings of our meta-analysis to the results of a bootstrapping analysis. Our results corroborate the bulk of studies, which suggests that networks and alliance experience play an important role in generating rents from innovation resources through both direct and indirect effects. The practical implication is that firms need to engage in networks and also develop strong alliance management capabilities to be able to increase the contribution innovation resources can make to their performance.     

Reaching phase free adaptive fuzzy synergetic power system stabilizer

In this paper, an adaptive fuzzy power system stabilizer is developed based on robust synergetic control theory and terminal attractor techniques. The main contribution consists in making the dynamic system insensitive to parameters variation. This aim is achieved using a new synergetic controller design such that power system states start, evolve and remain on a designer chosen attractor toward the equilibrium point therefore avoiding transient mode. Rendering the design more robust, fuzzy logic systems are used to approximate the unknown power system dynamic functions without calling upon usual model linearization and simplifications. Based on an indirect adaptive scheme and Lyapunov theory, adaptation laws are developed to make the controller handle parameters variations due to the different operating conditions occurring on the power system and to guarantee stability. The performance of the proposed stabilizer is evaluated for a single machine infinite bus system and for a multi machine power system under different type of disturbances. Simulation results show the effectiveness and robustness of the proposed stabilizer in damping power system oscillations under various disturbances and better overall performance than classical PSS and some other types of power stabilizers.