Adaptive hierarchical update particle swarm optimization algorithm with a multi-choice comprehensive learning strategy

Since many PSO variants are easily trapped in local optima from which they can barely break free, this paper proposes an adaptive hierarchical update particle swarm optimization (AHPSO) algorithm. The new term “local optimum early warning” is first defined to reflect the risk of being trapped in a local optimum. It plays a key role in the global coordinated control to determine the paradigm evolution direction and adjust the trajectory of particles in different risk environments. After that, the adaptive hierarchical update method generates two-layer and three-layer update formulas for the global exploration subpopulation and the local exploitation subpopulation, respectively, in order to improve the capability to resist the temptation of local optima. Consisting of the weighted synthesis sub-strategy and the mean evolution sub-strategy, the multi-choice comprehensive learning strategy is then employed to develop the most suitable learning paradigm to guide the motion path. Moreover, 18 benchmark functions and one real-world optimization problem are employed to evaluate the AHPSO against eight typical PSO variants. According to the experimental results, the AHPSO outperformed other methods in solving different types of functions by yielding high solution accuracy and high convergence speed.

     

液相色谱法测定水中苯丙[a]芘的不确定度评估

对液相色谱法测定生活饮用水中苯丙[a]芘含量测量不确定度进行分析,为评价检测数据的准确性提供科学依据。测样量为1m L时,测定生活饮用水中苯丙[a]芘含量为ρ=(0.856+0.025)μg·m L-1。通过对不确定度来源的量化分析,得出标准物质引入的不确定度分量和线性误差引入的不确定度分量是测定结果不确定度的重要来源。     

Large‐Stroke Electrochemical Carbon Nanotube/Graphene Hybrid Yarn Muscles

Artificial muscles are reported in which reduced graphene oxide (rGO) is trapped in the helical corridors of a carbon nanotube (CNT) yarn. When electrochemically driven in aqueous electrolytes, these coiled CNT/rGO yarn muscles can contract by 8.1%, which is over six times that of the previous results for CNT yarn muscles driven in an inorganic electrolyte (1.3%). They can contract to provide a final stress of over 14 MPa, which is about 40 times that of natural muscles. The hybrid yarn muscle shows a unique catch state, in which 95% of the contraction is retained for 1000 s following charging and subsequent disconnection from the power supply. Hence, they are unlike thermal muscles and natural muscles, which need to consume energy to maintain contraction. Additionally, these muscles can be reversibly cycled while lifting heavy loads.     

基于统计的中文地名自动识别研究

中文地名的自动识别是命名实体识别任务中难度较大的任务之一,目的是从中文文本中自动准确提取地理专用名词.文中使用统计模型中的条件随机场对中文地名的自动识别在字一级粒度进行了研究.在研究中利用条件随机场能任意添加特征的优点,合理引用了丰富的特征组合,在大规模语料上进行训练,统计获得标注序列基于特征集的条件概率分布,并采用序列标注的方式,实现中文地名的自动识别.多次闭合测试和开放测试结果F1值为90％左右,识别效果良好.     

Experimental investigation and thermodynamic reassessment of the Fe–Si–Zn system

Based on the critical evaluation of the experimental data available in the literature, the isothermal section of the Fe–Si–Zn system at 873 K was measured using a combination of X-ray analysis and scanning electron microscopy with energy-dispersive X-ray analysis. No ternary phase is observed at 873 K. A thermodynamic modeling for the Fe–Si–Zn system was then conducted by considering the reliable experimental data from the literature and the present work. All the calculated phase equilibria agree well with the experimental ones. It is noteworthy that a stable liquid miscibility gap appears in the computed ternary phase diagrams although it is metastable in the three boundary binaries.     

可重构系统在线任务预约重调度算法

针对可重构系统的任务调度问题,提出一种基于最小裕度优先策略的在线任务预约重调度算法。该算法在任务预约的基础上,对预约失败的任务和已预约的任务按特定优先策略进行重调度。仿真实验结果显示,在正常负载率区间中,该算法有效降低了任务拒绝率,且运行开销较小。     

Simultaneous state estimation and parameter identification in linear fractional order systems using coloured measurement noise

In the present paper, the identification and estimation problem of a single-input–single-output (SISO) fractional order state-space system will be addressed. A SISO state-space model is considered in which parameters and also state variables should be estimated. The canonical fractional order state-space system will be transformed into a regression equation by using a linear transformation and a shift operator that are appropriate for identification. The identification method provided in this paper is based on a recursive identification algorithm that has the capability of identifying the parameters of fractional order state-space system recursively. Another subject that will be addressed in this paper is a novel fractional order Kalman filter suitable for the systems with coloured measurement noise. The promising performance of the proposed methods is verified using two stable fractional order systems.     

Two types of El Niño and extratropical sea-level pressure variations

This study applies the nonlinear canonical correlation analysis (NLCCA) to explore the nonlinear relationship between the sea-level pressure (SLP) anomalies over the extratropical North Pacific and sea surface temperature (SST) anomalies in the tropical Pacific during 1985–2009. Our results suggest that the asymmetry between the warm eastern Pacific (EP) El Niño–Aleutian Low mode and the cool EP La Niña–anti-phase of the Aleutian Low mode is exhibited in the first NLCCA mode. Nonlinearity of the first NLCCA SST field is enhanced after 1998, and vice versa for the SLP field. The second NLCCA SST mode reveals weak nonlinearity representing the nonlinear central tropical Pacific (CP) El Niño–CP La Niña modes, while the second SLP field depicts the North Pacific Oscillation and anti-phase with the Aleutian Low phases. The nonlinearity of the second SST and SLP NLCCA modes is found to decrease gradually with time. During 1985–1997, the SST field exhibits linearity, while the SLP field shows weak nonlinearity. During 1997–2009, the SST and SLP fields both display weak linearity. Nonlinearity between the extratropical SLP and SST fields is further weakened from the first period. The Aleutian Low pattern could be excited by both EP and CP El Niños. Moreover, the CP El Niños have more connections with the North Pacific Oscillation state rather than the EP El Niños. Conclusively, this study reveals the asymmetric modes between the SLP and SST by the nonlinear method, and contributes to the understanding of the extratropical SLP variability response to two types El Niño events.     

Image compression-encryption scheme combining 2D compressive sensing with discrete fractional random transform

Multimedia Tools and Applications - Most of the existing image encryption algorithms based on compressive sensing are too complex to operate. An image compression-encryption scheme with simple...