基于激光粒度仪的回收油脂鉴别研究

目的开发一种能对回收油脂进行有效鉴别的简便、快捷新方法。方法采用马尔文激光粒度仪对27种未经使用食用油以及5种回收油脂中颗粒物粒度大小进行测定,并对此32种油中颗粒物的粒度大小及其分布范围进行比较。结果未经使用的27种食用油中颗粒物粒度平均峰值均小于10 nm,而5种回收油脂中颗粒物粒度平均峰值均大于300 nm。结论回收油脂中颗粒物粒度要大于食用油的颗粒物粒度,通过2类油脂中颗粒物粒度峰值的差异可以进行回收油脂鉴别。本文采用激光粒度仪鉴别回收油脂,无需对样品进行任何前处理,测试过程简便、快捷。     

Optimized tool path generation based on dynamic programming for five-axis flank milling of rule surface

This paper presents a computation scheme that generates optimized tool path for five-axis flank milling of ruled surface. Tool path planning is transformed into a matching problem between two point sets in 3D space, sampled from the boundary curves of the machined surface. Each connection in the matching corresponds to a possible tool position. Dynamic programming techniques are applied to obtain the optimal combination of tool positions with the objective function as machining error. The error estimation considers both the deviation induced by the cutter at discrete positions and the one between them. The path planning problem is thus solved in a systematic manner by formulizing it as a mathematical programming task. In addition, the scheme incorporates several optimization parameters that allow generating new patterns of tool motion. Implementation results obtained from simulation and experiment indicate that our method produces better machining quality. This work provides a concise but effective approach for machining error control in five-axis flank milling.     

Lagrangean relaxation approach to joint optimization for production planning and scheduling of synchronous assembly lines

This paper focuses on simultaneous optimisation of production planning and scheduling problem over a time period for synchronous assembly lines. Differing from traditional top-down approaches, a mixed integer programming model which jointly considers production planning and detailed scheduling constraints is formulated, and a Lagrangian relaxation method is developed for the proposed model, whereby the integrated problem is decomposed into planning, batch sequencing, tardiness and earliness sub-problems. The scheduling sub-problem is modelled as a time-dependent travelling salesman problem, which is solved using a dynasearch algorithm. A proposition of Lagrangian multipliers is established to accelerate the convergence speed of the proposed algorithm. The average direction strategy is employed to solve the Lagrangian dual problem. Test results demonstrate that the proposed model and algorithm are effective and efficient.     

数据集成方法发展与展望

数据集成在数据管理与分析领域起着重要的作用.尽管从学术界首次提出并开始研究数据集成问题已经过去30多年,但在各个领域仍然存在着大量与数据集成问题密切相关的问题亟待解决.对数据集成领域从2001年开始到现在相关工作的发展脉络进行了梳理与总结.通过追踪数据集成方法的发展轨迹,不仅可以了解前人在解决该问题时所作出的努力以及发掘出的研究方向,还可以进一步了解各个数据发展领域所研究问题的成因以及发展脉络.最终,通过分析近几年数据集成方面的工作,可以进一步展望未来在数据集成领域的潜在研究方向,为从事相关领域研究的学者提供参考.     

基于主题短语的搜索引擎结果聚类

为了解决搜索引擎检索结果中的主题混杂现象,帮助用户快速准确地定位到有价值的信息,提出基于主题短语的搜索引擎结果聚类方法。首先从检索结果中提取查询词并与相邻词语组成主题短语,建立包含高频独立词语及主题短语的混合向量空间模型,同时引入同义词词林对特征项进行语义扩充,最后采用改进的k-means聚类算法对搜索结果进行聚类,并为各个类别提取类别标签。实验结果表明,该算法能有效提高聚类结果的准确率。     

高非线性石英基光子晶体光纤产生宽带可调中红外孤子的实验研究

通过研究发现双包层结构能降低石英基光子晶体光纤损耗,并制备一种高非线性双包层结构石英基光子晶体光纤来进行实验研究.使用钛宝石飞秒激光器将实验室自制的石英基光子晶体光纤在反常色散区泵浦,研究不同的泵浦功率和泵浦波长对中红外超短脉冲孤子的影响,并分析了石英基高非线性光子晶体光纤中红外超短脉冲孤子产生的物理机理.结合实验发现在泵浦功率为827 nm,功率从0.1 W增加到0.42 W时,中红外第一个孤子随功率增加从1933 nm移动到2403 nm,可调范围达到470 nm,为石英基光子晶体光纤产生宽带可调超短脉冲源创造了很好的条件.     

近似到达时间约束下的语义轨迹频繁模式挖掘

随着GPS定位技术的不断发展与智能移动设备的普及,轨迹数据的获取变得越来越容易,同时,轨迹数据相关应用的需求也逐渐增多.在轨迹数据上加入语义信息,可以得到体积较小、质量较高、能够更好地反映用户行为的语义轨迹,在其上实现旅游线路推荐、路线预测、用户生活模式挖掘、朋友推荐等应用,可以更好地满足用户需求.挖掘语义轨迹的频繁模式是实现这些应用的技术基础,而在很多情况下,用户对语义轨迹频繁模式常存在到达时间方面的需求,比如按特定时间游玩热门景点的同时需要按时到达车站候车.现有的语义轨迹模式挖掘方法大多没有考虑到达时间的约束,挖掘出的频繁模式缺少到达时间信息;少数方法考虑了精确的到达时间,但因为约束太强会导致无法挖掘到频繁的模式.因此,首次对近似到达时间约束下的语义轨迹频繁模式（approximate arrival-time constrained frequent pattern,简称AAFP）挖掘方法进行了研究,并给出了其形式化定义;通过时间轴划分提出了挖掘AAFP的基线算法,并通过建立索引AAP-tree提出了改进后的高效、灵活的AAFP挖掘算法;之后提出了信息熵增量公式,并给出了时间轴划分及AAP-tree的高效维护方法;最后在真实数据集上进行实验,验证了方法的有效性及高效性.     

贴片机的虚拟样机研究

以贴片机为对象，研究虚拟样机技术在贴片机开发中的实际应用。首先使用UG软件对三种贴片机进行了三维实体建模，然后导入动力学仿真软件ADAMS，产生贴片机的“虚拟样机”，再对贴片机进行运动仿真分析，得出了运动学和动力学参数，为今后物理样机的设计和制作提供依据。     

A Deep Residual Network for Geometric Decontouring

Grayscale images are intensively used to construct or represent geometric details infield of computer graphics. In practice, displacement mapping technique often allows an 8-bit grayscale image input to manipulate the position of vertices. Human eyes are insensitive to the change of intensity between consecutive gray levels, so a grayscale image only provides 256 levels of luminances. However, when the luminances are converted into geometric elements, certain artifacts such as false contours become obvious. In this paper, we formulate the geometric decontouring as a constrained optimization problem from a geometric perspective. Instead of directly solving this optimization problem, we propose a data-driven method to learn a residual mapping function. We design a Geometric DeContouring Network (GDCNet) to eliminate the false contours effectively. To this end, we adopt a ResNet-based network structure and a normal-based loss function. Extensive experimental results demonstrate that accurate reconstructions can be achieved effectively. Our method can be used as a relief compressed representation and enhance the traditional displacement mapping technique to augment 3D models with high-quality geometric details using grayscale images efficiently.