CIMS企业全局信息模型的建模技术

计算机集成制造系统的关键在于信息集成，建立ＣＩＭＳ企业全局信息模型是信息集成的基础。本文介绍了“ＯＯＣＩＭ－－建立ＣＩＭＳ企业全局信息模型的技术”课题及研究背景，论述了ＣＩＭＳ企业全局信息建模的技术，包括信息模型的表达方式及模型组成，全局信息模型的总体结构，建模的过程及其计算机辅助建建模环境等。     

带常数输入率TB模型的全局稳定性

研究了各分类均具有常数输入率先的一个TB模型的全局稳定性。根据广义的Bendixson判据，证明了当输入中含有受感染者时，模型不存在无病平衡点而具有唯一的地方病平衡点。当感染者的治愈率较小时，证明了该平衡点的全局渐近稳定性。     

含两时滞企业竞争与合作模型的全局吸引性

研究了具有两时滞的非自治企业竞争与合作动力学模型的动力学行为。应用不等式技巧和构造多重 Lyapunov 函数的方法得到了模型的最终有界性和全局吸引性的充分条件。作为所得主要结论的应用，对所研究模型的三个特殊情况进行了研究，并得到了所研究模型的最终有界性和全局吸引性的充分条件。最后，两个数值例子进一步验证了所得结论的有效性和合理性。从所得主要结论和两个数值实例可以得到，两个离散时滞影响模型全局吸引性的结论。所得主要结论改进和推广了目前已有的关于两企业竞争与合作动力学模型方面的相关研究。     

边界注意力辅助的动态图卷积视网膜血管分割

针对视网膜血管分割任务中存在的毛细血管分割遗漏和断连的问题，从最大限度地利用视网膜血管的特征信息的角度出发，添补视网膜血管的全局结构信息和边界信息，在U型网络的基础上，提出边界注意力辅助的动态图卷积视网膜血管分割网络。本模型先将动态图卷积嵌入到U型网络中形成多尺度结构，提升模型获取全局结构信息的能力，以提高分割质量，再利用边界注意力网络辅助模型，增加模型对边界信息的关注度，进一步提高分割性能。将模型在DRIVE、CHASEDB1和STARE三个视网膜图像数据集上进行实验，均取得了较好的分割效果。实验结果证明，该模型能较好地区分噪声和毛细血管，分割出结构较完整的视网膜血管，具有泛化性和鲁棒性。     

基于全局背景模型和竞争者模型的说话人确认系统

大多数说话人确认系统都设置一个背景模型用于描述假冒者的特性。文章提出一种新的说话人确认的背景模型,对所有说话人采用同一全局背景模型(简称UBM),并为每个说话人建立一个竞争者模型(cohort model)。在全局背景模型不能做出准确判断的情况下,启用竞争者模型再次进行判决。该模型充分利用了传统全局背景模型和竞争者模型的互补性。实验表明新的背景模型使系统性能有较明显的提高。     

一类具有交叉传染的流行病接种模型

通过对一类具有交叉传染的流行病接种模型进行分析，借助李雅普诺夫函数和Krasnoselakii技巧，得到结论：若该模型仅存在无病平衡点，则无病平衡点是全局渐近稳定的；若该模型有地方病平衡点存在，则无病平衡点是不稳定的，而正平衡点是渐近稳定的。     

无约束优化二阶曲线法的力学模型及全局收敛性

本文讨论无约束最优化数值方法的二阶曲线方法，首先给出关于一般曲线法的全局收敛性定理及其证明，然后在欧几里空间Ｒ＾Ｎ中引入力学，给出了Ｒ＾Ｎ中Ｌａｇｒａｎｇｅ运动学方程及其数学上的推导，利用力学概念，给出几个具体的二阶曲线法模型，并给出了它们的全局收敛性分析。     

基于发电运营辅助决策模型的遗传算法研究

本研究应用遗传算法优化发电运营辅助决策模型，并利用仿真实验证明了遗传算法应用于发电运营辅助决策模型时的最优算子配置建议，研究结果表明，遗传算法在处理离散，非连续模型方面性能优良，收敛速度快，具备全局寻优能力，同时，利用遗传算法进行发电运营辅助决策的模型优化，可以让模型在实际应用中的更优良、更简单和更可靠。     

关于三种群第三类功能性反应周期系数模型的研究

讨论了一类三种群第三类功能性反应模型，得到了其存在全局渐进稳定周期解及唯一性的条件。     

蛋白质结构预测的优化模型与方法

从头预测方法是一种主要的蛋白质空间结构预测方法，其核心内容是恰当地建立并求解一个复杂的全局优化问题，40年来，虽然也取得了许多研究成果，但该问题的研究始终没有克服两个方面的困难，即如何找到一个表征蛋白质结构与能量关系的势能函数和一种有效的全局优化方法，主要介绍了蛋白质结构预测的优化模型和方法。     

听力正常老年人皮层听觉诱发电位研究

文章研究了听力正常老年人的P1-N1-P2波的特征值及其影响因素,并初步探讨其与言语感知之间的相关性。对40例听力正常的老年人进行了不同频段言语刺激声条件下的P1-N1-P2波测试与不同信噪比条件下的言语识别率测试。使用非参数检验分析不同言语刺激声频段P1-N1-P2波各波潜伏期、幅值的差异性,使用斯皮尔曼(Spearman)相关性检验分析老年人年龄、纯音听阈与P1-N1-P2波潜伏期、幅值之间的相关性;使用Spearman相关性检验分析P1-N1-P2波各波潜伏期和幅值与言语识别率之间的相关性。结果表明,刺激声频段、年龄、纯音听阈对听力正常老年人P1-N1-P2波各波潜伏期、幅值有显著影响,听力正常老年人P1-N1-P2波特征值与言语感知具有相关性。     

Ge-nanodot multilayer nonvolatile memories

1-5 period multilayers of Ge nanodots (NDs) for nonvolatile memories have been self-assembled by ion beam sputtering deposition of an ultra-small amount of Ge between SiO(2) layers at room temperature without post-annealing. High-resolution transmission electron microscopy demonstrates the existence of Ge ND layers well defined with respect to the SiO(2)/Si interface. The memory window that is estimated by capacitance-voltage hysteresis is proportional to the period, and finally reaches a plateau of about 11?V asymptotically over three periods. The program speed is enhanced over the full pulse-time range by increasing bias voltage or period. The charge-loss speed in the programmed state is slower in the samples with larger period. These memory properties are discussed based on possible physical mechanisms.     

Processing a conventional magnetic bubble circuit with a 6-µm period

A conventional magnetic bubble memory with a 6-μm period and submicron details has been made. The memory is an 8-kbit shift register single-mask design with field access NiFe propagation elements. The transfer gates and detector area have an 8-μm period, while the major part of the storage loop has an enhanced density with a 6-μm period. The processing is done with a 1:1 electron image projector, which is capable of making the 0.75-μm smallest features necessary for this circuit. The fabrication uses a lift-off technology with Ti followed by a reactive sputter-etch procedure for the structuring of the NiFe elements.     

An on-chip superconducting clock with two modes

A superconducting clock based on a 2-junction SQUID (superconducting quantum interference device) flip-flop with feedback is presented. The feedback consists of transmission lines that emanate from and return to the SQUID; the entire clock is built as a compact integrated circuit. The period of the clock is mainly determined by the length of transmission line, and there are two modes of operation that can be separately excited whose periods are in a ratio of 2:1. I-V data for a pair of clocks with different designed periods confirm the presence of the two modes, show how period depends on length, and give information on the switching time of the SQUID flip-flops. Specifically, the I-V data show that there exist both a fundamental model for flux bias at odd multiples of Φ ₀/2 (half-flux quantum) and a doubled mode with precisely half the period flux bias at even multiples. Clocks with longer transmission lines have longer periods, but simple scaling does not occur due to other sources of time delay     

LABORATORY STUDIES OF REPETITIVE WORK. II : PROGRESS REPORT ON RESULTS FROM TWO SUBJECTS

This experiment is the first or a series undertaken to test proposals put forward earlier by the first author that in repetitive work (i) output would be higher and variability less if breaks were given at the end of an actite period (period of optimum performance) rather than at the point when output decreased; (ii) the end of an actile period would be indicated by the onset of irregularity in performance which could be determined by the incidence longcycle times in unpaced work and an increase in the number of missed cycles in paced work; and (iii) the length of an actile period will depend on the demand made by the job and upon the capacity of the worker to meet the demand (her actility)

Results from two subjects tested for a period of 3 1/ 2 months suggest that proposal (i) is correct. A condition in which two breaks were given at limes indicated by an increase in long times in unpaced performance gave a significantly better output and lower variance than a condition in which one break was given at a time indicated by a fall in output. Both subjects had relatively fewer misses in the paced condition when three breaks were given than when working continuously

The technique for obtaining long times in unpaced work which formed part of (ii) was found to be practical and a simpler method was devised. The results obtained seem to confirm that the method has validity. No definite conclusions can be drawn on paced work

There is some tentative confirmation of (iii); in the paced condition the actile period seems to have been 1 hour compared with 1 1/4hours in the unpaced condition. Further, the better worker gave her best unpaced performance when rest was given after 1 1/4 hours whereas the less good worker did best when rest was given after 1 hour.     

趋势预测1/8周期快速寻北法

保证陀螺经纬仪寻北精度的同时,缩短寻北时间实现快速寻北具有重要意义.从陀螺仪寻北原理出发,建立陀螺运动轨迹的数学模型.基于数字化测量光路建立了非线性回归模型,通过欠周期的采集数据,预测整周期函数信息,研究1/8周期快速寻北方法,实现陀螺开始寻北1 min以内高精度快速寻北,开辟快速寻北的新途径.以改进型JT-15陀螺仪为样机的寻北试验表明,在陀螺开始寻北56 s内,仪器寻北测量精度优于0.831 1’.     

Analyzing topic evolution in bioinformatics: investigation of dynamics of the field with conference data in DBLP

In this paper we analyze topic evolution over time within bioinformatics to uncover the underlying dynamics of that field, focusing on the recent developments in the 2000s. We select 33 bioinformatics related conferences indexed in DBLP from 2000 to 2011. The major reason for choosing DBLP as the data source instead of PubMed is that DBLP retains most bioinformatics related conferences, and to study dynamics of the field, conference papers are more suitable than journal papers. We divide a period of a dozen years into four periods: period 1 (2000–2002), period 2 (2003–2005), period 3 (2006–2008) and period 4 (2009–2011). To conduct topic evolution analysis, we employ three major procedures, and for each procedure, we develop the following novel technique: the Markov Random Field-based topic clustering, automatic cluster labeling, and topic similarity based on Within-Period Cluster Similarity and Between-Period Cluster Similarity. The experimental results show that there are distinct topic transition patterns between different time periods. From period 1 to period 3, new topics seem to have emerged and expanded, whereas from period 3 to period 4, topics are merged and display more rigorous interaction with each other. This trend is confirmed by the collaboration pattern over time.     

On forecasting large and infrequent snow avalanches

Snow avalanches that threaten a highway or a residential area are often large avalanches that have a return period > 1 year. Danger assessment strongly relies on precipitation data since these avalanches are typically triggered by major snow storms. Given the extensive protection work that is in place in the European Alps, the avalanche control service (also called avalanche commission) responsible for danger assessment will usually monitor the avalanche situation throughout the winter, but only become active in case of a major snow fall. Related safety concepts describing the procedures and measures to be taken in a given danger situation are therefore often based on threshold values for new snow. By analysing the avalanche occurrence of a major avalanche path, we show that forecasting based on new snow amounts involves high uncertainty. Whereas the return period of an avalanche to, for example, the road was about 5 years, the return period for the corresponding new snow depth was substantially smaller, in our case slightly less than 2 years. Similar proportions were found for a number of other avalanche paths with different snow climate. The return period of the critical new snow depth was about 2–5 times smaller than the return period of the avalanche. This proportion is expected to increase with increasing return period. Hence, based on the return period of an avalanche path a first estimate for the critical new snow depth can be made. With a return period of the critical new snow depth of 1–2 years, avalanche prediction for individual avalanche path becomes very challenging since the false alarm ratio is expected to be high.     

Manchester encoded bandpass sigma-delta modulation for RF class D amplifiers

An analysis of a continuous-time bandpass sigma-delta modulator in a configuration with an upconverter is given for a RF class D amplifier application. The upconverter multiplies the modulator pulse train with a synchronised clock signal and maps each modulator bit to an integer multiple k of a (+1, -1) or (-1, +1) pattern depending on the sign of the modulator bit. The upconversion is equivalent to an extension of Manchester encoding, which is usually defined for k=1. The analysis focuses on evaluating the impact of upconversion on the modulator coding efficiency and the average pulse period. A design equation is derived, which shows that coding efficiency is dependent only on the upconversion frequency ratio, while the average pulse period depends only on k. The equations provide a designer with a way of evaluating the trade-offs in the amplifier system and show that encoding with k=1 is the most efficient configuration for maximising coding efficiency and minimising switching power loss