甲型H1N1流感传播的SIR模型研究

建立了一个甲型H1N1流感传播的改进SIR模型,并用微分方程数值解中的四阶Runge-Kutta方法进行求解。用墨西哥的病例数据对模型验证表明,结果与真实数据基本吻合。SIR模型所得数据与GM(1,1)灰色预测模型数据及二次、四次曲线拟合数据作比较,可知SIR模型误差最小。     

武汉城市圈地方政府间合作机制构建

2007年12月武汉城市圈正式成为"全国资源节约型和环境友好型社会建设综合配套改革试验区(简称‘两型社会')".如何应对环境和资源问题成为武汉城市圈进一步发展的关键,而从政府治理的角度来讲,加强政府间的合作和交流成为了关键中的关键.通过采用文献法、比较研究法、实证分析法等研究方法,依据地方政府合作理论及区域经济一体化理论等相关理论知识,分析在建设两型社会的背景下武汉城市圈各政府合作所面临的困境,并在研究、分析区域经济下地方政府合作理论及实践的基础上提出新形势下以市场为导向、分层级合作的地方政府合作新机制.     

Nano-gold supported on TiO2 coated glass-fiber for removing toxic CO gas from air

A process for coating a layer of TiO₂ on the surface of glass fiber (Pyrex) was developed to support nano-gold on the fiber. The sol–gel method was utilized. The solution was composed of tetrapropyl titanate (TPT), isopropanol (i-PrOH), HCl and H₂O. The XRD pattern indicated that TiO₂ was in its anatase form after the coated fiber was calcined at 450 °C. In the preparation of nano-gold on the fibers (coated with TiO₂), deposition was performed in a pH-adjusted gold chloride solution. The catalytic activities of the resulting fibers were examined by the oxidation of CO in an air stream at room temperature. The gold containing fibers dried at room temperature contained less metallic gold and exhibited poorer CO oxidation activity than did those dried at 60 °C Moreover, the catalytic activities of the fibers depended on the gold concentration during deposition. Therefore, the gold fibers from the solution with gold concentrations of 2 × 10⁻⁴ M exhibited better CO oxidation activity than those from the solutions with concentrations of 1 × 10⁻³ and 0.7 × 10⁻⁴ M. TEM and A.A. analysis show that different concentrations of the gold solution were associated with different particle sizes and different gold loadings on the fibers, and therefore different catalytic activities of the fibers (per unit weight of fibers). 0.1 g of fibers prepared from the 2 × 10⁻⁴ M gold solution removed all CO from the air stream (containing 1% CO at a flow rate 110 cm³/min) at room temperature, approximately meeting the European Community EN403 (1993) standard for a qualified CO gas mask material.     

Adaptive annealing learning algorithm-based robust wavelet neural networks for function approximation with outliers

In this study, a robust wavelet neural network (WNN) is proposed to approximate functions with outliers. In the proposed methodology, firstly, support vector machine with wavelet kernel function (WSVM) is adopted to determine the initial translation and dilation of a wavelet kernel and the weights of WNNs. Then, an adaptive annealing learning algorithm (AALA) is adopted to accommodate the translations, the dilations, and the weights of the WNNs. In the learning procedure, the AALA is proposed to overcome the problems of initialization and the cut-off points in the robust learning algorithm. Hence, when an initial structure of the WNNs is determined by a support vector regression (SVR) approach, the WNNs with AALA (AALA-WNNs) have fast convergence speed and can robust against outliers. Two examples are simulated to verify the feasibility and efficiency of the proposed algorithm.     

一种重叠视域多摄像机环境下的运动目标匹配SHFSM算法

针对重叠视域下多摄像机间目标匹配问题,提出了一种基于色度特征信息的色度特征区间集合匹配算法.通过分析目标颜色色度分量对光照强度的不变性,依据色度分量直方图定义了色度特征区间,并证明了其相关特性.该算法首先获取目标色度特征区间集合,并依据区间内特征信息像素的数量对特征区间进行排序,最后采用模糊匹配原理对排序的色度特征区间集合进行匹配.实验结果表明,算法匹配正确率可达95％,通过与经典算法对比体现了其准确率高、可靠性强的优点.     

Effect of organoclay on the thermal stability,mechanical strength,and surface wettability of injection‐molded ABS–clay nanocomposite materials prepared by melt intercalation

In this article, a series of polymer–clay nanocomposite (PCN) materials consisted of commercial thermoplastic ABS matrix and dispersing inorganic organoclay platelets were successfully prepared by melt intercalation through the twin‐roller mixer. The as‐prepared materials in the form of pellet were then shaped by injection‐molding machine and the as‐molded specimens were subsequently examined by chemical characterizations, through Fourier transformation infrared (FTIR) spectroscopy, powder X‐ray diffraction (XRD), and transmission electron microscopy (TEM). Effect of the organoclay on thermal stability, mechanical strength, and surface wettability of PCN materials, in both the form of standard dumbbell shape and pellet, was studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile test, hardness test, and contact‐angle measurements, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99; 1576–1582, 2006     

A crosstalk model and its application to stereoscopic and autostereoscopic displays

We propose a model to quantify the crosstalk phenomenon for stereoscopic and autostereoscopic displays, separate crosstalk contributed from co‐location image contrast (CIC) and system crosstalk (SCT), introduce gray scale dependency of CIC, modify model for gray scale dependency of SCT in active type 3D displays, and apply the model to derive the 3D luminance and SCT measurement formulas. The model might serve as a basis for the 3D metrology, and the results of this research should be of reference value to hardware makers and inspectors of stereoscopic and autostereoscopic displays.     

Implication of Cognitive Style in Designing Computer‐Based Procedure Interface

Different people have different models of mental perception, which form the bases of human reactions. The design of human‐computer interfaces should consider these differences in the cognitive models of users to achieve maximum benefits. The Myers‐Briggs Type Indicator (MBTI) is an accepted tool for measuring four dimensions of an individual's cognitive model. This research investigated the effects of two interface designs based on the characteristics of the Sensing/iNtuitive (S/N) and Thinking/Feeling (T/F) categories. These interfaces were designed for the visual information displays of computer‐based procedures at a nuclear power plant. Because of the nature of this industry, quicker reaction times are required and fewer mistakes are tolerated. A group of subjects were selected, and the subjects were assigned to either the ST or NT group before the experiment. The results, when compared with earlier statistics for a single design for all users, indicate that reaction times were reduced in some critical situations and the number of mistakes was reduced. © 2011 Wiley Periodicals, Inc.     

An opportunistic resource allocation approach for mixed QoS and non-QoS connections in OFDMA wireless networks

An opportunistic resource allocation approach is proposed to guarantee both fair resource allocation and high system throughput under combinations of QoS and non-QoS connections in OFDMA networks. This approach features dynamic connection classification and packet prioritization based on real-time network conditions and QoS constraints. A classifier is first employed to prioritize QoS connections by observing the channel state of each subscriber station and the utilization of network resources. It performs a finite-horizon Markov decision process with dynamic rules affected by system load. The transmission order of packets is then determined by an opportunistic multiservice scheduler according to the QoS requirements of connections and the output of the classifier. Having the scheduling result, an allocator assigns slots to the scheduled packets, and its output is linked back to the connection classifier through a resource usage observer for all subscriber stations. The sub-channel allocation problem is also solved by cooperation between the slot allocator and the packet scheduler. Results of numerical analysis and NS2 simulation confirm the advantages claimed above. The same conclusion can also be drawn from the comparison with several existing approaches in terms of system throughput, service successful ratio, average spectral efficiency, and system revenue.