Optimal shift partitioning of pharmacies

The pharmacy service requires that some pharmacies are always available and shifts have to be organized: a shift corresponds to a subset of pharmacies that must be open 24 hours a day on a particular week. Under the requirement that each pharmacy belongs to exactly one shift and the assumption that users minimize the distance to the closest open pharmacy during each shift, we want to determine a partition of the pharmacies into a given number of shifts, such that the total distance covered by users is minimized. It may be also required that shift cardinalities are balanced. We discuss different versions and the related computational complexity, showing that the problem is NP-hard in general. A set packing formulation is presented and solved by branch-and-price, together with a fast solution technique based on a tabu search. They have been applied to real and random instances showing that (i) the set packing formulation is very tight and often exhibits no integrality gap; (ii) the branch-and-price solves problems of practical relevance to optimality in a reasonable amount of time (order of minutes); (iii) the tabu search finds optimal or near-optimal solutions in order of seconds.     

扫描式X光机及DDS在其运动控制中的应用

扫描式X光机是一种高精度，高性能的新型医疗设备，其显著优点在于大大降低了患者所受X光辐射剂量，可直接得到患者清晰的X光数字图像，缩短出片时间，X光片资料存储方便，便于实现远程诊断，该设备对运动控制部分的匀速性，平稳性和多次扫描的位置重复性的要求均很高。本文主要针对其运动控制部分的结构特点，分析了影响运动性能的主要原因，并将直接数字频率合成器应用于调速，从而实现了对其运动控制部分的要求。     

Analysis of information exchange activities to actualize and validate situation awareness during shift changeovers in nuclear power plants

Shift work situations occur in almost all safety‐critical organizations, and the investigations of some catastrophes like Chernobyl, Exxon Valdez, and the Gol/Legacy mid‐air collision indicated that shift work information exchange played an important role during the evolution of the situation before the accidents. Inadequate communications during shift changeovers challenged operators' work in the moments that preceded these accidents, because they got inadequate information about the current situation. Our research focuses on the information exchange activities (verbal, written, and nonverbal) of nuclear power plant control operators during shift changeovers. Our aim is to investigate how verbal exchanges and other representations enable operator crews to share information regarding the events that occurred in the previous shift to achieve adequate situation awareness. Our findings indicated the importance and richness of the information exchange during the shift changeover process to update and validate individual and collective situation awareness, showing that information adequately shared enables the ad hoc configurations of regulation loops and a safer use of simplified strategies that can be understood and be validated by other operators, reducing the occurrence of cognitive overloads and contributing to the construction of a common cognitive ground that enhances system resilience. © 2010 Wiley Periodicals, Inc.     

与低计算复杂度解映射相结合的16APSK星座优化

提出一种在新的简化的解映射方法下,以星座图上所有信号点距离解映射门限的最小距离的最大化为目标函数的星座图优化方法。仿真比较了在优化设计的星座映射下,传统的解映射算法和所提出的解映射的误码性能。仿真结果表明,所提出的星座图优化设计方法在简化的解映射方法下具有良好的性能;简化的解映射算法在大大降低计算复杂度的情况下,在误比特率为10-4时,SNR损失了约1 d B。     

工业变换炉最佳催化剂粒度

本文在建立数学模型的基础上，用计算机模拟变换炉的操作工况，考察改变催化剂粒度对经济效益的影响，从而得到工业变换炉催化剂颗粒最佳尺寸，开发了以经济效益为考察依据，工业反应器中催化剂颗粒最佳尺寸的计算方法。     

基于均值漂移的提取羽毛杆的去噪方法研究

为有效去除羽毛片图像中的噪声,便于毛叶与毛杆的分割,提出用均值漂移算法对毛片图像进行平滑滤波,然后对图像进行区域合并,最后利用阈值分割算法提取羽毛杆.实验结果表明:利用均值漂移算法能有效去噪,可以获得更高的图像评价指数和更好的视觉效果,可有效滤除不必要的纹理背景信息,为准确提取毛杆奠定重要基础.     

AMT汽车模糊三参数换挡规律研究

为了使AMT汽车自动变速器换挡能够反映路况与车况变化,更好地满足汽车换挡平顺性要求,提出了AMT汽车模糊三参数换挡控制。论文首先给出了模糊三参数换挡控制原理,接着设计了模糊三参数换挡控制器,最后给出了长安羚羊AMT轿车模糊三参数换挡仿真,并与模糊两参数换挡进行了比较。结果表明,采用模糊三参数换挡比采用模糊两参数换挡更加符合驾驶员的换挡经验和习惯,比传统计算法求解换挡规律更简便,易于实现,鲁棒性更强。     

基于DESO的Mean Shift目标跟踪算法研究

将基于DESO的运动预测算法和Mean Shift算法相结合,形成一种新的基于Mean Shift的快速目标跟踪算法.该算法以DESO预测位置作为Mean Shift算法下一帧候选模型的计算中心,实现了对快速运动目标的跟踪,并通过DESO对目标运动轨迹进行预测,较好地解决了目标完全遮挡时的跟踪问题.实验结果表明,该算法具有预测精度高、实时性好、抗遮挡能力强的优点.     

School timetabling for quality student and teacher schedules

The school timetabling problem, although less complicated than its counterpart for the university, still provides a ground for interesting and innovative approaches that promise solutions of high quality. In this work, a Shift Assignment Problem is solved first and work shifts are assigned to teachers. In the sequel, the actual Timetabling Problem is solved while the optimal shift assignments that resulted from the previous problem help in defining the values for the cost coefficients in the objective function. Both problems are modelled using Integer Programming and by this combined approach we succeed in modelling all operational and practical rules that the Hellenic secondary educational system imposes. The resulting timetables are conflict free, complete, fully compact and well balanced for the students. They also handle simultaneous, collaborative and parallel teaching as well as blocks of consecutive lectures for certain courses. In addition, they are highly compact for the teachers, satisfy the teachers’ preferences at a high degree, and assign core courses towards the beginning of each day. Dr. Birbas is currently the Director for Primary and Secondary Education in the Region of Western Greece.     

改进的Mean Shift滤波在砂砾岩图像分割中的应用

砂砾岩图像成分颜色多样、色彩不均,要有效地进行分割,提取砾岩颗粒,图像预处理就显得尤为重要。MeanShift滤波相比传统的滤波算法具有更好的平滑特性,能很好地消除噪声和色彩不均对后续分割造成的影响,但运算速度较慢。针对该问题,提出利用高斯金字塔和像素点赋值方法改进Mean Shift滤波算法速度。采用改进后的Mean Shift滤波算法对砂砾岩图像进行预处理,然后进行分割,提取粒岩,取得了较好的效果。