Analysis of aging effects - From transistor to system level

Due to shrinking feature sizes in integrated circuits, additional reliability effects have to be considered which influence the functionality of the system. These effects can either result from the manufacturing process or external influences during the lifetime such as radiation and temperature. Additionally, modern technology nodes are affected by time-dependent degradation i.e. aging.Due to the age-dependent degradation of a circuit, processes on the atomic scale of the semiconductor material lead to charges in the oxide silicon interface of CMOS devices, altering the performance parameters of the device and subsequently the behavior of the circuit. With the continuous downscaling of modern semiconductor technologies, the impact of these atomic scale processes affecting the overall system characteristics becomes more and more critical. Therefore, aging effects need to be assessed during the design phase and actions have to be taken guaranteeing the correct system functionality throughout a system's lifetime.This work presents methods to investigate the influence of age-dependent degradation as well as process-variability on different levels. An operating-point dependent sizing methodology based on the g_m/I_D-method extended to incorporate aging, which aims at developing aging-resistent circuits is presented. Additionally, the sensitivity of circuit performances in regard to aging can be determined. In order to investigate the reliability of a complex system on behavioral level, a modeling method to represent the performance of system components in dependence of aging and process variability is introduced.     

基于动态标签的关系抽取方法

针对远程监督数据集的关系抽取研究方法存在着大量标签噪声的问题,提出了一种作用于分层注意力机制关系抽取模型的动态标签方法。首先，提出了一种根据关系类别相似性生成动态标签的概念。由于相同的关系标签包含相似的特征信息，计算特征信息的关系类别相似性有助于生成与特征信息相对应的动态标签。其次，利用动态标签方法的评分函数来评价远程监督标签是否为噪声，以决定是否需要生成新的标签代替远程监督标签，通过调整远程监督标签来抑制标签噪声对模型的影响。最后，根据动态标签来更新分层注意力机制以关注有效实例，重新学习每个有效实例的重要性，进一步抽取关键的关系特征信息。实验结果表明，相较于原始的分层注意力机制关系抽取模型，所提方法在Micro和Macro分数上分别有1.3个百分点和1.9个百分点的提升，实现了噪声标签的动态纠正，提升了模型的关系抽取能力。     

Optimization of rice wine fermentation process based on the simultaneous saccharification and fermentation kinetic model☆

Chinese rice wine making is a typical simultaneous saccharification and fermentation(SSF) process.During the fermentation process,temperature is one of the key parameters which decide the quality of Chinese rice wine.To optimize the SSF process for Chinese rice wine brewing,the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatures were determined in batch cultures using a mathematical model.The kinetic parameters as a function of temperature were evaluated using the software Origin8.0.Combing these functions with the mathematical model,an appropriate form of the model equations for the SSF considering the effects of temperature were developed.The kinetic parameters were found to fit the experimental data satisfactorily with the developed temperature-dependent model.The temperature profile for maximizing the ethanol production for rice wine fermentation was determined by genetic algorithm.The optimum temperature profile began at a low temperature of 26 °C up to 30 h.The operating temperature increased rapidly to 31.9 °C,and then decreased slowly to 18 °C at 65 h.Thereafter,the temperature was maintained at18 °C until the end of fermentation.A maximum ethanol production of 89.3 g·L~(-1)was attained.Conceivably,our model would facilitate the improvement of Chinese rice wine production at the industrial scale.     

永磁步进电机数字控制系统设计

采用AT89 C51单片机为核心控制芯片,对步进电机转速及转向控制系统进行设计.实现了电机的启动和停止控制、正转和反转控制,以及加速和减速控制,并能动态显示在LED数码管上.该系统可靠性较高、稳定性好、结构简单、运行可靠、控制方便且性价比高,有一定的使用价值.     

Modeling the profitability of power production from short-rotation woody crops in Sub-Saharan Africa

Increasing electricity supply in Sub-Saharan Africa is a prerequisite to enable economic development and reduce poverty. Renewable sources such as wood-fueled power plants are being promoted for social, environmental and economic reasons. We analyzed an economic model of a vertically integrated system of short-rotation woody crops (SRWC) plantations coupled with a combined heat and power (CHP) plant under Sub-Saharan African conditions. We analyzed a 5 MW (electric) base-case scenario under Ugandan conditions with a 2870 ha Eucalyptus grandis plantation and a productivity of 12 t ha⁻¹ y⁻¹ (oven dry basis) under a 5-year rotation. Plant construction and maintenance constituted 27% and 41% of total costs, respectively. Plantation productivity, carbon credit sales as well as land, fuel, labor & transport costs played an economic minor role. Highly influential variables included plant efficiency & construction costs, plantation design (spacing and rotation length) and harvest technologies. We conclude that growing 12–24 t ha⁻¹ y⁻¹ at a five year rotation can produce IRR's of 16 and 19% over 30-years, respectively. Reducing rotation length significantly reduced short-term financial risk related to frontloaded costs and relatively late revenues from electricity sales. Long-term feed-in tariffs and availability of a heat market played a significant economic role. The base-case scenario's 30-year IRR dropped from 16% to 9% when a heat market was absent. Results suggest a leveling-off of economies-of-scale effects above 20 MW (electric) installations. Implementation-related research needs for pilot activities should focus on SRWC productivity and energy life cycle analysis.     

无可信第三方的数据匿名化收集协议

针对半诚信的数据收集者对包含敏感属性(SA)数据收集和使用过程中可能造成隐私泄露问题,该文在传统模型中增加实时的数据领导者,并基于改进模型提出一个隐私保护的数据收集协议,确保无可信第三方假设前提下,数据收集者最大化数据效用只能建立在K匿名处理过的数据基础上。数据拥有者分布协作的方式参与协议流程,实现了准标识(QI)匿名化后SA的传输,降低了数据收集者通过QI关联准确SA值的概率,减弱内部标识揭露造成隐私泄露风险;通过树形编码结构将SA的编码值分为随机锚点和补偿距离两份份额,由K匿名形成的等价类成员选举获取两个数据领导者,分别对两份份额进行聚集和转发,解除唯一性的网络标识和SA值的关联,有效防止外部标识揭露造成的隐私泄露;建立符合该协议特性的形式化规则并对协议进行安全分析,证明了协议满足隐私保护需求。     

基于三质心模型的类人机器人射门算法

为了实现快速稳定的射门动作,提出了一种基于三质心模型的类人机器人射门轨迹规划方法。首先,根据三质心模型,得到包含游动腿轨迹和躯干轨迹的零力矩点(ZMP)方程, 采用三次贝塞尔曲线规划游动腿轨迹和ZMP轨迹,根据ZMP方程求解出类人机器人的躯干轨迹;其次,在双腿支撑相根据线性摆模型计算类人机器人的质心轨迹,实现射门姿态的快速调整;最后,在RoboCup 3D仿真平台中应用此算法实现了类人机器人的快速射门动作,并与其他球队的射门动作进行了对比。实验结果表明：应用该算法仅需手工调试即可快速实现稳定的射门动作,射门动作时间有很大减少,可增强机器人足球队的竞争力。     

多粒子角色协同作用的混合粒子群优化算法

针对粒子群优化(PSO)算法易陷入局部最优和后期收敛速度慢的问题,提出一种多粒子角色协同作用的混合粒子群算法(MPRPSO)。引入粒子角色的概念,将种群粒子分成探索粒子(EP)、巡逻粒子(PP)和局部开发粒子(LEP)三类角色,在每次迭代中利用探索粒子以标准PSO算法搜索解空间,用基于混沌的巡逻粒子加强全局搜索,并在陷入局部最优时替代部分探索粒子,恢复种群活力。最后通过局部开发粒子的单维异步邻域搜索加强算法局部搜索能力,加快收敛。实验独立运行30次,所提算法在粒子角色比例为0.8∶〖KG-*2〗0.1∶〖KG-*2〗0.1的条件下,在Sphere、Rosenbrock、Ackley和Quadric函数中获得的平均值分别为2.352E-72、4.678E-29、7.780E-14和2.909E-14,尤其在Rastrigrin与Griewank函数中能收敛到最优解0,优于其他对比算法。实验结果表明,所提算法在优化性能上有所提高,并有一定的鲁棒性。     

基于图着色的P2P流媒体数据调度算法

为了提高P2P流媒体的传输性能,提出一种基于图着色的数据调度算法。算法规定加入系统的每个节点和数据块都被分配某种颜色,请求节点优先获取相同颜色的数据块。根据数据稀有性、紧急性、新鲜性定义数据块优先级别,同时评估伙伴节点数据提供能力,以选择恰当的数据提供者。该算法能有效平衡节点负载,合理利用系统带宽,使数据分布更均匀,提高了系统传输性能。仿真实验表明,算法在数据填充率、启动延迟、数据到达率等重要指标上都优于传统数据调度算法。     

不均匀网络中的局域搜索免疫

当前研究的热点是怎么样用最小的代价对人群网络或计算机网络进行免疫。基于节点连接的不均匀性提出的目标免疫被认为是最好的免疫策略。已知邻居节点的度数,在不均匀网络中提出了局域搜索免疫。与目标免疫策略相比,该策略可以通过免疫相等或较少的节点来消灭病毒。实验使用SIS病毒传播模型在ER随机网络、BA无标度网络和两种实际网络中测试了局域探索免疫策略,它的免疫性能随着聚类系数的增加而增加。