基于ASL的模型驱动架构测试方法

针对模型驱动架构（MDA）下的软件开发方法中测试启动比较晚、难以发现隐藏在模型中的缺陷及UML模型描述缺乏精确语义等问题,提出了基于ASL的模型测试方法：从UML模型出发,将动作规约语言（ASL）运用于平台无关模型（PIM）上建立测试模型。给出了ASL语句在MDA过程中的工作原理、平台无关模型的建立过程、测试用例建立的步骤、测试执行的实施过程,最后结合实例,在UML图的基础上运用ASL对测试环境进行构建,并创建了系统的测试用例,对模型及业务逻辑进行了测试。实验结果表明,提出的基于ASL的模型测试方法既能利用模型驱动对复杂的测试用例进行简化和抽象,又能在软件生存期早期揭示软件的缺陷,防止缺陷随着软件开发过程的进行而被放大。     

支持跨步访问的嵌入式存储系统

提出了一种新型多素数嵌入式存储系统,能够显著改善系统跨步访问的性能。提高跨步访存的带宽,对于改善系统的整体性能有着重要的意义。但是,在嵌入式系统中,受片外结构的尺寸限制,直接应用经典的素数存储系统理论无法显著改善跨步访存性能。为此,该新型系统以素数存储系统理论为基础,引入主存访问调度策略并结合嵌入式系统的实际结构特征,构造了一种两层结构的多素数存储系统,可以用较少数量的存储模块实现,而且从逻辑地址到物理地址的映像计算简单,能够以相对较小的硬件代价实现对嵌入式存储系统跨步访问的有效支持。理论分析和实验结果均证实了该系统的正确性和有效性。     

基于树搜索算法的多用户MIMO系统的自由度分配

针对最大化多用户MIMO系统的和速率的问题,提出了将迭代式干扰对齐技术（Iterative Interference Alignment：ⅡA）和系统自由度（DoF）分配策略相结合的一种算法.系统的DoF分配是通过树搜索算法（Tree search）来实现的.理论分析及实验仿真结果表明,该算法获得的系统容量,接近遍历法（exhausting search：EX）的结果,但是在算法复杂性及收敛时间上明显优于遍历法.     

太阳能溴化锂吸收式制冷系统吸收特性的研究

太阳能溴化锂吸收式制冷系统的吸收器采用传热、传质分离装置,利用预冷器预先冷却和喷淋吸收的方法完成对传热、传质的分离。通过建立吸收器的计算模型,分析冷冻水出口温度、冷却水进口温度、热水温度、喷淋温度、喷淋密度等因素对传热、传质的影响。利用传热、传质分离方法,使系统的吸收特性得到强化,从而使系统获得较高的性能系数。     

Hydrodynamics of gas-solid flow around immersed tubes in bubbling fluidized beds

A numerical study was conducted based on the gas-solid two-fluid model using the body-fitted coordinate system to analyze the behavior of particles and bubbles flow in bubbling fluidized beds without and with immersed tubes. The kinetic theory of granular flow was implemented in the model. The images of simulated instantaneous particle concentration and velocity gave the process of the formation, coalescence and eruption of bubbles. The effects of the tube pitch and superficial gas velocity on the fluidization in a bubbling fluidized bed were investigated. Calculated bubble frequencies without and with immersed tubes were in agreement with previous experimental and simulation findings. The wavelet multi-resolution analysis was used to analyze the simulated data of instantaneous particle concentration. From the random-like particle concentration fluctuations, the fluctuating components due to particle flow and bubble motion can be extracted based on the wavelet multi-resolution analysis over a time-frequency plane.     

烧结法微晶玻璃装饰板材的力学性能研究

本文研究了烧结法微晶玻璃装饰板材的密度、抗折强度等力学性能,讨论了成分、结构对密度、抗折强度的影响.     

Transitions from solid to liquid in isotactic polystyrene studied by thermal analysis and X-ray scattering

A three-phase model, comprising mobile amorphous fraction (MAF), rigid amorphous fraction (RAF) and crystalline fraction (C), has been applied to interpret the thermal transitions and structure of cold-crystallized isotactic polystyrene (iPS) from below the glass transition temperature, T_g, to above the melting point. Quenched amorphous iPS films were isothermally crystallized at different temperatures for 12 h. The fraction of crystalline phase, ?_c, was measured by differential scanning calorimetry (DSC), wide angle X-ray scattering and Fourier Transform infrared spectroscopy. The fraction of the mobile amorphous phase, ?_MAF, was obtained from the heat capacity increment at the glass transition temperature. In the three-phase model, the fraction of the rigid amorphous phase, ?_RAF, was found from 1−?_MAF−?_c. Specific heat capacity measurements by standard DSC confirm that the experimental baseline heat capacity conforms to a three-phase model for temperatures ranging from below T_g, up to the relaxation of RAF. The relaxation of RAF appears as a sigmoidal change in heat capacity accompanied by excess enthalpy, in which solid-like RAF is converted to an identical amount of liquid-like MAF.At temperatures above the relaxation of RAF, either one or two major crystal melting endotherms are observed in standard DSC, dependent upon crystallization temperature. However, using quasi-isothermal temperature modulated DSC, we always observed two reversing melting endotherms. The effects of annealing on iPS structure during the quasi-isothermal measurement were assessed using small angle X-ray scattering (SAXS). Combining the DSC and SAXS results, a model for the melting of iPS lamellae at low heating rates is presented.     

An algorithm and observability research of autonomous navigation and joint attitude determination in asteroid exploration descent stage

In this paper, an autonomous relative navigation and joint attitude determination algorithm in asteroid exploration descent stage is researched based on feature point information of perpendicular asteroid surface image observed by optical navigation camera, distance vectors from spacecraft to asteroid measured by three angled installed lidars and relative velocity increment measured by accelerometer when the relative distance vector to the centroid of asteroid can not be obtained. The inertial attitude of spacecraft is determined by sun vector, star vectors and inertial angular velocity respectively measured by sun sensor, star trackers and inertial reference unit. Also, in order to obtain measurement error model transferred from sensor noise, a covariance matrix solver considering error correlation is presented via the error model of normalized vector to first order. Numerical simulation and improved observability evaluation of filtering are undertaken to discuss the results of complete sensor observation and weak observation of lidars, and verify the effectiveness of the presented relative navigation and attitude determination algorithm.     

医院信息系统项目管理的现状与突破

自20世纪90年代以来,我国医院信息系统发展迅速。到目前为止,全国绝大部分医院实现了信息化管理,并且逐步向区域医疗信息资源共享模式迈进。在医院信息化建设进程中,随着信息系统规模日益庞大,信息管理部门对它的驾驭能力捉襟见肘,原有粗放式的管理模式已远不能适应工作需要。有必要重新审视医院信息系统项目管理模式,实现新的突破。本文以医院信息科为视角,探讨将项目管理九大手段运用到医院信息系统项目建设过程中的作用及效果。     

工控设备的安全保密风险评估实践

近期披露的信息安全事件表明,工控系统已经成为国外信息安全攻击的主要目标,必须加强工控系统的信息安全防护。工控系统与办公系统不同,系统中使用智能设备、嵌入式操作系统和各种专用协议,尤其是智能设备具有集成度高、行业性强、内核不对外开放、数据交互接口无法进行技术管控等特点,工控系统的安全风险评估方法、标准还在不断探索中。本文介绍工控设备安全保密风险评估模型和评估流程,以数控设备840D为例,进行工控设备的安全保密风险评估,围绕工控设备全生命周期给出了安全保密防护和检测的建议。