Trajectory P system

Membrane computing is a branch of natural computing aiming to abstract computing ideas for the structure and the functioning of living cells as well as from the way the cells are organized in tissues or higher-order structures. Trajectories are used as a tool for modeling language operations and other related objects. A trajectory P system consists of a membrane structure in which the object in each membrane is a collection of words and the evolutionary rules are given in terms of trajectories. In this paper, we present some properties of trajectory P systems.     

膜计算在图像处理领域应用研究综述

随着计算机与信息技术的高速发展,图像处理已深入到各行各业,海量数据以及复杂算法所面临的高速实时处理成为图像处理领域急需解决的问题.膜计算是由生物细胞(群)相关机理启发的一类分布式、并行计算模型,已被证明能以多项式时间求解计算难问题.综述膜计算在图像处理领域中的应用,着重从图像低层处理(图像平滑、骨架提取)和中层处理(图像分割、立体匹配、图像配准、图像分解与重建)两方面对膜计算在图像处理领域的应用进行了介绍和分析,并给出了膜计算应用于图像处理领域的今后可能的发展方向.     

模糊膜计算模型与应用研究综述

膜计算是由生物细胞(群)相关机理启发的一类分布式、并行计算模型.膜计算模型已被证明是强大的并且以多项式时间复杂性求解众多的NP(non-deterministic polynomial)问题.膜计算模型与算法是膜计算领域的核心关键问题,特别是面向应用问题的模型和算法.模糊膜计算是近年开发的一种膜计算模型,它能克服先前模型在处理不确定性问题上的限制,得到极为广泛的关注.目前,模糊膜计算模型已在诸如电力系统故障诊断、微网控制中得到应用.首先简要地介绍几种模糊P系统,然后描述它们在工程问题中的应用.     

链式膜系统及直接(间接)膜算法与聚类分析研究进展

当前关于膜计算的研究有很多,但是大部分都停留在理论研究层面,关于膜计算的应用研究依然比较少.现有膜系统主要包括细胞型膜系统、组织型膜系统和神经型膜系统.现有膜系统及其变形都是基于图结构的设计,为了进一步扩展膜系统的应用能力,将现有的基本膜系统结合离散Morse理论,创建了新型的单纯形P系统.同时将细胞的多维框架思想加入膜系统研究中,从形式化的角度,创建了膜系统的链式结构.将膜系统的极大并行性和聚类分析模型进行结合,不仅可以用于处理高复杂度、数量庞大的数据集,而且还可以提高聚类算法的性能,具有广泛的应用价值.针对两种新型膜系统进行了详细介绍,同时将膜系统与聚类问题进行结合的研究进行了概述.     

P Systems Generating Iso-Picture Languages

P systems generating rectangular arrays and hexagonal arrays have been studied in the literature, bringing together the two areas of theoretical computer science, namely membrane computing and picture languages. Recently a new class of picture languages called the class of iso-picture languages generating interesting picture lan-guages have been introduced . In this paper, we develop a class of tissue-like P systems with active membranes as a generative device for iso-picture languages.     

基于位置的可拼接轨迹对搜索

移动设备的快速发展,生成了大量轨迹.基于位置的轨迹搜索,是指给定一组查询点,从数据集中检索top-k条轨迹,但是所得到的轨迹可能不能近距离通过所有查询点.利用轨迹可拼接的想法,提出基于位置的可拼接轨迹对搜索,使用户利用轨迹对得到的轨迹更加近距离地通过所有查询点.在搜索终止过程,给出可拼接的轨迹对搜索过程的有效终止条件.真实的数据集验证了所提方法的有效性.      

Spark环境下基于网格索引的轨迹k近邻查询方法

移动对象轨迹的k近邻(k nearest neighbor trajectories,kNNT)查询是一种重要的空间信息服务,主要用于寻找与给定轨迹最近邻的k条轨迹,被广泛地应用于智能交通、信息推荐等领域。随着轨迹数据量的快速增长,由于单机计算资源的限制,传统集中式环境下的kNNT查询效率和可扩展性无法满足实际要求。为了解决这个问题,设计了轨迹数据的分布式网格索引结构,该索引在Spark环境下将轨迹切分并映射到网格中,并引入轨迹还原表以保留查询时候选子轨迹段间的连续性。基于此索引,提出了Spark环境下的轨迹k近邻查询方法kNNT-Grid。实验结果表明,kNNT-Grid方法在分布式环境下实现了良好的查询效率和可扩展性,能够应对海量轨迹数据的k近邻查询需求。     

基于拟能量的高超声速飞行器再入轨迹优化

考虑高超声速飞行器再入过程总加热量最小,基于拟能量将单段轨迹优化转化为多段轨迹优化问题,采用非等间距控制变量参数化方法对每段轨迹分别优化.高超声速飞行器再入轨迹必须满足热流率、动压和过载3个约束.通过把控制变量参数化,同时引入时间尺度变换和不等式约束转化方法,将轨迹优化问题转化为含有约束的非线性规划问题.基于拟能量概念,将再入轨迹进行了分段优化,以4段为例进行了仿真,计算时间比单段情况下缩短了约50%.     

The trajectory parameters analysis of saltating sand grains driven by wind

The study of trajectory parameters of saltating sand grains is of great importance to forming the kinematic theory of wind-sand current. By establishing the simplified theoretical pattern and probing into the relationship between lift-off angle (α) and landing angle (β), relationship between the ratio of saltation length ( L) to maximum height (H) and lift-off angle as well as the angular variation laws of any point on the trajectory, it has been demonstrated that the relations among these parameters are nonlinear. Meanwhile, it has also been proved that the theoretical analysis is basically reliable in accordance with the wind tunnel experiments using high-speed multiflash photography. Generally, the trajectory shapes of saltating sand grains are controlled precisely and the theoretical analysis is closely combined with the experimental results.     

非线性系统中轨线的最小李雅普诺夫指数的计算

提出了计算连续系统中轨线的最小李雅普诺夫指数的方法。该法对研究三维自治系统的混沌轨线最有利。用此法得到的Ｌｏｒｅｎｚ吸引子和Ｒｏｓｓｌｅｒ吸引子的最小李雅普法诺夫指数和已知结果吻合。     

Static three-dimensional culture of human hepatocarcinoma cell with microcarriers

Traditional monolayer culture is still the common method used in hepatocarcinoma cell culturein vitro. For lack of the structure similar to thatin vivo, it is disadvantageous in the research of the relation between structure and function. We established a three-dimensional (3-D) culture model of human hepatocarcinoma cell (BEL-7402)in vitro by using microcarrier cytodex-3 in static condition. The results of SEM, TEM, enzyme activity and flow cytometry indicated that the cells were polygonal-shaped and arranged in multilayers. Intercellular space was 0.5–2.0 μm wide where lots of microvilli could be seen. Adjacent cells were connected with desmosomes and localized membrane projects. More than 90% of the cells were viable and maintained the consumption of glucose and the expression of EGF receptor. The intracellular ALT, AST and LDH-L activities were higher in 3-D culture than those of monolayer culture. Compared with monolayer culture, this 3-D culture with the structure similar to trabecular hepatocarcinomain vivo is much more suitable for the research of the interactions of cell-cell and cell-microenvironment, and might be useful in the investigation of the mechanisms of invasion, metastasis, and multicellular drug resistance of tumor cells.     

飞行动目标RCS可视化计算

通过动力学方程和运动学方程计算飞行动目标的飞行轨迹,利用飞行扰动模型计算飞行过程中的飞行随机抖动,将图形电磁计算的方法推广到计算飞行动目标的雷达散射截面,并比较了考虑随机抖动前后的计算结果.     

静电宽束曲轴二级近似轨迹的分析与计算

检验曲轴轨迹计算方法的合理性与可靠性。方法利用同心球系统,结果曲线坐标系下宽电子束曲轴的主轨迹方程以及考虑到二级近似下的曲轴轨迹方程进行具体的计算。结论由此验证曲轴轨迹计算方法是合理可靠的。     

Progress in measuring biophysical properties of membrane proteins with AFM single-molecule force spectroscopy

Membrane proteins are crucial in cell physiological activities and are the targets for most drugs.Thus,investigating the behaviors of membrane proteins not only provide deeper insights into cell function,but also help disease treatment and drug development.Atomic force microscopy is a unique tool for investigating the structure of membrane proteins.It can both image the morphology of single native membrane proteins with high resolution and,via single-molecule force spectroscopy(SMFS),directly measure their biophysical properties during molecular physiological activities such as ligand binding and protein unfolding.In the context of molecular biomechanics,SMFS has been successfully used to understand the structure and function of membrane proteins,complementing the static three-dimensional structures of proteins obtained by X-ray crystallography.Here,based on the authors’antigen-antibody binding force measurements in clinical tumor cells,the principle and method of SMFS is discussed,the progress in using SMFS to characterize membrane proteins is summarized,and challenges for SMFS are presented.     

冗余度机器人的障碍物躲避

给定机械手的初始形态和终端所希望的轨迹以及在工作空间内的障碍物,本文研究冗余度机器人无碰撞运动的规划问题,提出了基于J函数障碍物躲避的算法.关节坐标空间的安全轨迹的计算可通过障碍物躲避的性能指标而得到.由于J函数的计算仅与一些极点有关,计算量小,便于实时控制.仿真结果证明了所提出的算法的有效性.     

Identification of integrin-like in guard cells ofVicia faba

We addressed the existence and localization of integrin-like in guard cells ofVicia faba by using a probe of polyclonal antibody against the human integrin (α_vβ₃/β₅). Western blot results showed that three integrins-like of about 47.3, 43.7 and 41.1 ku were detected from the preparation of membrane fragments of purified guard cell protoplasts. Further research with immunofluorescent scanning microscopy indicated that those integrins-like were localized on plasma membrane of guard cells, most nearing the dorsal wall, which is consistent with the reception of signals from epidermal cells to guard cells. Thus our results indicate, for the first time, that integrins-like are present at guard cell plasma membrane ofVicia faba.     

基于Bi-BPNNs的船舶轨迹修复模型

为了解决船舶轨迹数据的异常和丢失问题,辅助轨迹复原和情景推演,提出一种双向学习模型,用于修复船舶轨迹.从AIS(Automatic Identification System)报文中提取航行船舶的上下文轨迹特征向量,改进基础BP(Back Propagation)神经网络的拓扑结构,构建具有双向预测功能的BP神经网络(Bi-BPNNs)模型,修复缺失的轨迹数据.使用长江干线航行船舶的真实轨迹数据对构建的模型进行验证和分析,通过与基础BP网络和常用线性插值方法的对比,证明Bi-BPNNs模型在船舶轨迹修复上具有更好的性能和效果.     

Localization of muscarinic acetylcholine receptor in plant guard cells

Acetylcholine (ACh), as an important neurotransmitter in animals, also plays a significant role in various kinds of physiological functions in plants. But relatively little is known about its receptors in plants. A green fluorescence BODIPY FL-labeled ABT, which is a high affinity ligand of muscarinic acetylcholine receptor (mAChR), was used to localize mAChR in plant guard cells. InVicia faba L. andPisum sativum L., mAChR was found both on the plasma membrane of guard cells. mAChR may also be distributed on guard cell chloroplast membrane ofVicia faba L. The evidence that mAChR localizes in the guard cells provides a new possible signal transduction pathway in ACh mediated stomata movement.