CMOS／SOSCC4066器件的可靠性研究

本文介绍了CMOS/SOS CC4066器件长期可靠性试验结果。对失效器件的分析表明,硅-蓝宝石技术没有新的失效机理。该器件的可靠性不低于国内体硅MOS IC能达到的水平,并接近“七专”器件的水平。     

基于双解码路径DD-UNet的脑肿瘤图像分割算法

针对医学图像中病灶区域尺度不一、边界模糊和周围组织强度不均匀所导致的分割精度降低问题,提出了一种基于双解码器的脑肿瘤图像分割模型。为了增强特征的表征力,提出了高阶微分残差模块并使用不同空洞率的扩张卷积用于提取特征编码,提高了网络模型的分割性能;引入上下文语义信息感知模块(multi scale dilation, MSD),从不同的目标尺度中提取更多的精细信息,提高了对结构细节信息的捕获能力,同时减少了编解码器之间的特征差异;在空间解码路径中使用选择性聚合空间注意力模块(spatial aggregation attention module, SAAM),增加了对有效空间特征的权重比例,减少了无效的特征干扰。在脑肿瘤数据集上进行了实验验证,实验结果表明,所提算法的Dice系数、平均交并比、敏感性、特异性、准确率等指标分别为：93.35%、90.71%、91.15%、99.94%、96.75%。     

Multi-layer microstructure fabrication by combining bulk silicon micromachining and UV-LIGA technology

A novel method for fabrication of multi-layer microstructures of microelectro-mechanical system (MEMS) devices is described. This technique, which combines bulk silicon micromachining technique and UV-LIGA technique can overcome some shape limitations of single technique on complex microstructures. To demonstrate this combination, the SU-8 microstructure fabricated in the etched silicon grooves is presented. In this fabrication process, a SU-8 removal method by fuming sulfuric acid was introduced and a novel type of plastics PETG was tried in microhot embossing process. The proposed fabrication process can be applied to fabricating a high-aspect-ratio microstructure for a large displacement actuator and precision sensors. Moreover, this combined process enables the fabrication of more complex structures, which cannot be fabricated by bulk micromachining or UV-LIGA alone.     

基于时空上下文信息的POI推荐模型研究

随着基于位置的社交网络(LBSN)技术的快速发展,为移动用户提供个性化服务的兴趣点(POI)推荐成为关注重点。由于POI推荐面临着数据稀疏、影响因素多和用户偏好复杂的挑战,因此传统的POI推荐往往只考虑签到频率以及签到时间和地点对用户的影响,而忽略了签到序列中用户前后行为的关联影响。为了解决上述问题,该文通过序列的表示考虑签到数据的时间影响和空间影响,建立了时空上下文信息的POI推荐模型(STCPR),为POI推荐提供了更精准的个性化偏好。该模型基于序列到序列的框架下,将用户信息、POI信息、类别信息和时空上下文信息进行向量化后嵌入GRU网络中,同时利用了时间注意力机制、全局和局部的空间注意力机制来综合考虑用户偏好与变化趋势,从而向用户推荐感兴趣的Top-N的POI。该文通过在两个真实的数据集上实验来验证模型的性能。实验的结果表明,该文所提出的方法在召回率(Recall)和归一化折损累计增益(NDCG)方面优于几种现有的方法。     

User location privacy protection mechanism for location-based services

With the rapid development of the Internet of Things (IoT), Location-Based Services (LBS) are becoming more and more popular. However, for the users being served, how to protect their location privacy has become a growing concern. This has led to great difficulty in establishing trust between the users and the service providers, hindering the development of LBS for more comprehensive functions. In this paper, we first establish a strong identity verification mechanism to ensure the authentication security of the system and then design a new location privacy protection mechanism based on the privacy proximity test problem. This mechanism not only guarantees the confidentiality of the user’s information during the subsequent information interaction and dynamic data transmission, but also meets the service provider’s requirements for related data.     

一种基于移动Agent的分布式通信算法

本文提出了一种基于移动Agent链接寻址分布式通信算法,通过分析通信位移延迟问题,对消息传递的寻址、消息排队的过程设置,实现了移动Agent的高速通信.     

基于IaaS云计算平台的弹性计费模型

文章认为计费系统是云计算平台不可缺少的重要组成部分。在分析中国外著名企业的云计费模式的基础上,文章针对基础设施即服务(IaaS)云计算平台,提出了一种基于租赁实体的计费模型与基于事件触发机制的计费模型相结合的计费模型,利用租赁实体的计费模型对空闲的主机进行调度,通过事件触发机制对计费信息进行统计。该计费模型使云计费方式更加灵活。     

Tunnel transition mechanism support all types of NAT users

Through the analied of current tunneling mechanism,a more efficient and applicable tunneling mechanism called TrNAT based on TSP to face different scenarios was proposed.Optimization of the communications between NAT users was achieved with ideology of MIPv6.Then,Shim6 was utilized to realize route redundancy and also improved the route aggregation of 6 to 4 tunnel.Finally,TrNAT tunneling mechanism was implemented on Linux kernel and validated by experiments.     

基于ADAMS的连续变焦机构运动仿真

某型红外热像仪在连续变焦过程中,局部出现了图像的模糊和抖动,严重影响了图像的质量。本文通过ADAMS对某型连续变焦机构进行仿真,对其动力学参数进行研究。之后对光学设计点进行优化,在符合成像质量要求的情况下,消除了变焦过程中图像的突变。     

nc-Ge/SiO2薄膜的光发射和光吸收研究

采用射频磁控反应溅射技术和后退火法制备了nc-Ge/SiO2薄膜材料。采用X射线衍射仪(XRD)对薄膜的微结构进行测试,随着退火温度的升高,衍射峰的半高宽减小,表明Ge纳米晶粒的平均尺寸逐渐增大,发现经过1 000℃退火后的薄膜具有三个明显的纳米锗衍射峰。薄膜的傅里叶红外吸收谱表明,随着退火温度的升高,薄膜的红外吸收增强。室温下,测量了不同温度退火下薄膜的光致发光谱,观察到了紫外光、紫光和橙色光。而且不同退火温度的薄膜,其光致发光谱有所不同,理论上着重讨论了紫光和橙光的发光机制。