Topological hierarchy-contour tracing algorithm for nests of interconnected contours

As a simple meaningful external illustration, a group of boundary contours is commonly used for representing the physical appearance of an object of interest on a 2D plane (e.g., a part drawing, CT scan image, a sliced layer, tile pattern). The illustration is understood from the composition of the contours and their attributes that include their shapes, sizes, locations and relationships. Therefore, not only is geometrical information important for contours to be useful in subsequent operations but their topological hierarchy relationships also are essential. Presented in this paper is a topological hierarchy-contour tracing algorithm that is capable of tracing nests of interconnected contours often found in practice and of identifying their topological hierarchy relationships automatically during contour tracing. The algorithm organizes contours by family rather than by group or as individual. However, contours are traced across families generation by generation instead of going deep with one family branch at a time. The outputs of the algorithm are ordered sequences of boundary pixels representing all closed contours and their topological hierarchy relationships. The algorithm has been implemented on LabVIEW, and tested with several samples to illustrate its applications.     

A fast triangulation algorithm for 3D reconstruction from planar contours

Aiming at the reconstruction of medical images, a fast triangulation algorithm from planar contours (FTA) is proposed in this paper. In FTA, the judgment of the similarity of counters is carried out at first. Then a traditional global optimisation method is applied to triangulating dissimilar counters. A simple local optimisation method is also applied on areas enveloped by line sections of similar counters. Through theoretical analysis and experience, the visual effect of FTA becomes approximately similar to traditional global optimisation methods and its calculating speed is much improved simultaneously. FTA was also applied to a stereo tactical radiation therapy planning system for a gamma knife (SRTPS) developed by the authors.     

A new approach for lofted B-spline surface interpolation to serial contours

This paper addresses the problem of B-spline surface interpolation to serial contours, where the number of points varies from contour to contour. A traditional approach to the problem creates a set of B-spline curves via B-spline curve interpolation to each contour, makes them compatible via degree elevation and knot insertion and performs B-spline surface lofting to get a B-spline surface that interpolates them. The approach tends to result in an astonishing number of control points in the lofted B-spline surface. This situation arises mainly from the inevitable process of progressively merging different knot vectors to make the B-spline curves compatible. This paper presents a new approach for fixing this problem. The approach includes a novel process of obtaining a set of compatible B-spline curves from the given contours. The process is based on universal parameterisation [1, 2], allowing the knots to be selected freely but leading to a more stable linear system for B-spline curve interpolation. Since the number of control points in each compatible B-spline curve is equal to the highest number of contour points, the proposed approach can realise efficient data reduction and provide a compact representation of a lofted B-spline surface while keeping the desired surface shape. Some experimental results demonstrate its usefulness and quality.     

硬币问题的一种新的通用算法的研究

在图像压缩、模式识别、筛选等工业应用中提出了搜索坏硬币的最优化问题,即用尽可能少的测试次数检测出坏硬币并确定轻重。对这一问题,可采用AO*算法、遗传算法等国际通用算法求解,但这些算法的时间复杂度和空间复杂度过大。因此提出了一种新的解决此类问题的通用算法,并用C++将其实现和测试。测试结果表明:算法的时间、空间和成功率均达到了理论极限。     

一种新型指纹图像分割算法

针对传统分割算法在含污迹较多的指纹识别应用中分割效果较差的问题,首先介绍了指纹图像分割的基本概念;然后对分割算法在输入指纹图像携带一定污迹、杂质等噪声环境下的鲁棒性进行了重点研究;最后,提出了一种新的基于最大类间方差法和传统方差法的分块处理的分割算法,并通过自适应滤波进一步平滑指纹图像的脊线及边界轮廓。实验结果表明,该方法较传统的分割算法能更好地完成实际应用中含污迹杂质较多的指纹的分割处理。     

A novel algorithm for quick and continuous tracing the change of radon concentration in environment

Several measurements of the radon concentration are performed by RAD7 in the University of South China. We find that 30-40 min is needed for RAD7 for tracing the concentration of the standard radon chamber. There are two reasons. The first is that the sufficient time of air cycle is needed for the radon concentration in internal cell of RAD7 equal to that of the environment; and the second is that the sufficient decay time is needed for the (218)Po concentration in internal cell of RAD7 equal to that of the radon. We used a zeroth order approximation to describe the evolution of the environment radon concentration, and obtained a novel algorithm for quick and continuous tracing the change of radon concentration. The corrected radon concentration obtained through this method is in good agreement with the reference value. This method can be applied to develop and improve the instruments for tracing the change of radon concentration quickly.     

A distributed interconnected control for computer-integrated manufacturing

An innovative control system architecture is considered which preserves the parallelism of the manufacturing operation with the goal of improving productivity through maximal use of resources with varying product mixes. To combine flexibility with efficiency, the expert integrated management (XIM) architecture technology is developed which governs a multiprocess environment with distributed intelligent interfaces and which controls the communication and synchronization tasks for each manufacturing situation. The performance of this distributed interconnected control system is demonstrated with the special purpose expert simulator (XIM-SIFIP), which combines the previously developed simulational facilities (XS-SIFIP, for flexible manufacturing sections and XT-SIFIP, for tool-supplying service) by means of a new information processing device that enables parallel control of the multiagent framework.     

结合梯度信息的主动轮廓模型图像分割算法

传统的C-V模型对于含有多灰度级目标的图像难以实现准确分割,并且分割速度非常缓慢.为了解决这些问题,提出了在C-V模型中引入梯度信息的图像分割算法.该算法在C-V模型的偏微分方程中加入了依赖于梯度信息的弱目标区域控制项和加速因子.弱目标区域控制项可以使弱目标被快速,稳定地锁定,加速因子的引入可以显著地提高C-V模型的分割速度.实验结果表明:该算法能够有效分割出弱目标和提高图像分割速度.     

一种新的分布式MIMO-OFDM系统同步算法

针对不等周期同步算法多段重复引起的同步峰值模糊的问题,提出了一种适用于多输入/多输出正交频分复用(MIMO-OFDM)系统的定时同步算法,算法在原有的不等周期同步模式(UPSP)算法的基础上对其进行结构的优化,同时利用Zadoff_Chu序列良好的互相关性来提高算法的性能。仿真结果表明,提出的算法在AWGN和多径信道下能有效地进行定时同步,特别是在多径情况下,新算法较UPSP算法能更有效地提高准确定时概率。     

弧齿锥齿轮的一种新型精确设计方法

提出了一种与加工方法无关的弧齿锥齿轮的精确设计方法.依据齿轮啮合基本定理,把弧齿锥齿轮的齿面作为空间自由曲面来处理,以球面渐开线及螺旋渐开面为基本数学手段推导出完整的设计算法并依据此方法做出三维实体造型.     

同轴度误差快速评定新算法

针对空间最小二乘拟合同轴度基准轴线算法效率较低的问题,提出一种同轴度误差快速评定新算法。根据空间最小二乘法拟合直线的思想,利用两次投影法,先将n个基准要素的轮廓圆心正截面投影到xo Y面上,求取拟合的基准轴线与xo Y面的交点,再将n个被测实际要素轮廓正截面圆心投影到xo Y面上,将三维问题转化为二维问题,进行同轴度误差评定。并对一组数据进行了MATLAB仿真,结果证明该算法准确,便捷且计算速度大幅度提高。     

一种基于LEACH的新型WSN路由算法

LEACH是针对无线传感器网络设计的低功耗自适应分簇聚类路由算法,与一般的平面多跳路由算法相比,LEACH算法可以将网络生命周期延长15%.但是,LEACH算法存在簇首开销较大、重复性成簇过多地浪费系统资源以及簇规模分布不合理等等不足.针对LEACH算法的不足,从簇的形态、成簇方式和簇首选择依据等方面对其进行了改进.改进后的算法采用固定分簇的方式;形成的簇是不均匀簇,即靠近Sink节点的簇的半径较大,而远离Sink节点的簇的半径较小;簇首选择的依据是节点的剩余能量.仿真实验证明,改进后的算法具有更高的能量使用效率.     

基于模糊PID的自主寻迹小车控制

小车寻迹过程中由于路况不同,其数学模型的参数会不断地发生变化,这使得以往的传统PID全局参数的整定极为困难。因此提出了一种基于模糊PID的控制策略。通过模糊控制整定PID的3个参数的变化量,从而根据路况的不同,实现PID三个参数的实时调节。同时应用仿真软件对系统的数学模型分别进行了传统PID和模糊PID的仿真。最后,在以飞思卡尔车模为基础的试验平台上进行模拟试验,验证了仿真结果和理论的准确性,以及模糊PID相比于传统PID的优越性。     

Improvement and realization of linear travel-time interpolation ray tracing algorithm

The linear travel-time interpolation ray tracing algorithm has a drawback: rays can’t go round the low velocity area if the launching point, the receiving point and the low velocity area distribute on the same column (row). Aiming at the drawback, an improved algorithm is proposed on the basis of researching reconstruction theories. The given algorithm adopts a cross-scanning strategy to carry out forward processing and uses discrete points as the secondary sources to simplify backward processing. The numerical simulation experiments show that the rays can go round the low velocity areas located in the same column (row) of the launching points and the receiving points. Rays scan over the global region only once.     

A new autotuning algorithm for PID controllers using dead-beat format

A novel algorithm for PID controllers based on dead-beat control and fuzzy inference mechanism is presented in this paper. The proposition is an extension of the work by the authors where the PI form of the algorithm was presented. The inclusion of the derivative term makes the method suitable for application in all types of processes including the ones having high rate disturbances. The proposed algorithm seems to be a complete and generalized PID autotuner as can be seen by the simulated and experimental results. In all the cases the method shows substantial improvement over the controller tuned with Ziegler Nichol's formula and the PI controller proposed in R. Bandyopadhyay, D. Patranabis, A fuzzy logic based PI autotuner, ISA Transactions 37 (1998) 227-235.     

一种新的基于梯度方向角的圆检测算法

针对基于Hough变换的圆检测方法具有时间复杂度和空间复杂度大的缺陷,提出了一种新的基于梯度方向角的圆检测算法,通过确定圆的任意一条直径的两个端点,即可以确定圆的参数空间(a,b,r),从而实现圆的检测.实验结果表明,采用该方法可以实现高效的圆检测,不仅显著降低了圆检测的平均时间复杂度,而且在检测过程中无需任何累加器的设计,从而克服了基于Hough变换的圆检测方法具有时间复杂度和空间复杂度大的缺陷.     

A new heuristic algorithm for a class of two-dimensional bin-packing problems

Due to the diversification of customer’ demands, cutting and packing enterprises need to arrange production plans flexibly. This paper proposes a heuristic algorithm to help enterprises make cutting or packing plans. With this algorithm, a class of different customer demands are considered, such as orientation of items and cutting style. The idea of this heuristic algorithm is from the dynamic programming idea by aggregating states to avoid the explosion of the number of states. The advantages of this algorithm are its flexibility, competitive computation time, and performance with respect to metaheuristics.     

A robust decentralized load frequency controller for interconnected power systems

A novel design of a robust decentralized load frequency control (LFC) algorithm is proposed for an inter-connected three-area power system, for the purpose of regulating area control error (ACE) in the presence of system uncertainties and external disturbances. The design is based on the concept of active disturbance rejection control (ADRC). Estimating and mitigating the total effect of various uncertainties in real time, ADRC is particularly effective against a wide range of parameter variations, model uncertainties, and large disturbances. Furthermore, with only two tuning parameters, the controller provides a simple and easy-to-use solution to complex engineering problems in practice. Here, an ADRC-based LFC solution is developed for systems with turbines of various types, such as non-reheat, reheat, and hydraulic. The simulation results verified the effectiveness of the ADRC, in comparison with an existing PI-type controller tuned via genetic algorithm linear matrix inequalities (GALMIs). The comparison results show the superiority of the proposed solution. Moreover, the stability and robustness of the closed-loop system is studied using frequency-domain analysis.     

A composite control design for suppressing mutual interference of interconnected systems

Journal of Mechanical Science and Technology - This paper presents a new disturbance decoupling and rejection method for a multi-connected system, and introduces the composite controller based on...     

A new automatic contact point detection algorithm for AFM force curves

A new method for estimating the contact point in AFM force curves, based on a local regression algorithm, is presented. The main advantage of this method is that can be easily implemented as a computer algorithm and used for a fully automatic detection of the contact points in the approach force curves on living cells. The estimated contact points have been compared to those obtained by other published methods, which were applied either for materials with an elastic response to indentation forces or for experiments at high loading rates. We have found that the differences in the values of the contact points estimated with three different methods were not statistically significant and thus the algorithm is reliable. Also, we test the convenience of the algorithm for batch‐processing by computing the contact points of a force curve map of 625 (25×25) curves. Microsc. Res. Tech. 76:870–876, 2013. © 2013 Wiley Periodicals, Inc.