基于儿童身心发展的益智玩具设计策略

从益智玩具设计的发展现状和儿童认知发展规律出发,探讨益智玩具对儿童身心发展的影响,提出研究现代儿童益智玩具设计策略:特定需要设计、互动体验设计、DIY互动设计.     

CVSD语音编解码的DSP实现

连续斜率可变增量调制(CVSD)语音编码简单且具有良好的抗信道误码能力,擅长处理丢失和被损坏的语音采样,较其他编码方法语音效果更清晰,可靠性更高,降低带宽的同时保证了语音质量.利用DSP芯片研制开发基于语音压缩编码技术的语音产品已经成为一大研究热点.选用TMS320VC5509芯片作为硬件平台,用C语言实现了CVSD语音编解码,能较好实时实现语音编解码.     

定向MWNTs/PMMA的原位聚合制备及耐磨损性

采用原位聚合方法制备了定向碳纳米管/聚甲基丙烯酸甲酯复合材料,并且研究了该复合物的耐磨损性.对定向碳纳米管及其复合物进行了傅立叶红外吸收光谱分析、扫描电镜及光学显微镜观察.采用砝码质量法评价了复合物的耐磨损性.分析结果表明,混酸处理后定向碳纳米管附带了-OH、-COOH基等极性基团.混酸处理后定向碳纳米管束状结构被破坏,定向碳纳米管可以单管形态分散于基体中,碳纳米管表面包覆着PMMA.砝码质量法耐磨损性测试结果表明,定向碳纳米管的加入可提高PMMA复合物的耐磨损性和耐划痕性,当定向碳纳米管用量为0.7%时,复合物的耐磨损性能提升了54%.     

Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves：convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.     

Method to compute the reachability set of S3PR

This paper proposes a novel approach to computing the reachability set by using place invariants and strict minimal siphons for S³PR with specific resource places. First, the set of invariant markings is enumerated. Then a necessary and sufficient condition is developed to decide whether a marking is spurious by analyzing the relationship between the number of tokens in the corresponding places of any strict minimal siphon and their bounds. In addition, the spurious markings are calculated. Finally, the reachability set of the net is generated by removing all the spurious markings from the set of invariant markings. Experimental results show the efficiency of the proposed method.     

德惠断陷下白垩统碎屑岩储层特征及控制因素分析

德惠断陷下白垩统登娄库组、营城组、沙河子组储层物性差,勘探风险大.利用岩心观察、铸体薄片鉴定、扫描电镜分析、黏土X线衍射分析等方法,分析储层基本特征、储层成岩作用和控制因素.结果表明:德惠断陷下白垩统碎屑岩储层成分成熟度和结构成熟度较低,储层孔隙类型主要有残余原生孔、次生孔和混合孔,储层物性和孔隙结构较差;压实作用是导致储层物性变差的主要原因,溶蚀作用改善储层物性;纵向上发育2个次生孔隙带,主要形成于中成岩期,次生孔隙带的形成与有机质生烃排酸和断裂有关.研究结果为德惠断陷下白垩统进一步油田勘探提供地质依据,对其他地区类似储层研究有一定借鉴意义.     

非平稳时序循环平稳趋势提取与机械故障诊断

在简单介绍非平稳时序模型周期趋势项提取方法的基础上，提出了机械故障诊断和分析方法，该方法利用旋转机械出现故障以后所呈现的循环平稳特性，使用循环平稳分析方法剔除非平稳时间序列模型中的趋势项，然后建立平稳时序模型，用该模型进行机械故障诊断分析。并运用仿真和实例对方法的正确性进行了验证。     

Web日志挖掘中的会话识别算法

会话识别是Web日志挖掘的关键步骤,然而很多方法所得到的会话不够精确.针对Web日志挖掘中的会话识别问题,在最常用的Timeout方法的基础上,提出了一种改进的基于平均时间阈值的识别方法.通过动态计算会话中请求记录间的平均时间间隔,个性化地调整页面的时间阈值,相对于传统的对所有用户页面使用单一的先验阈值,该方法能够更准确地识别出长对话.最后对生成的侯选会话集进行二次识别,使识别出的会话更为合理有效.实验结果表明,会话质量得到了提高.     

蚁群算法及其在路由优化中的应用综述

蚁群算法(ACO)是一类新型的机器学习技术,根据蚁群算法的正反馈原理和启发式原理的特点,针对目前国内国际的研究情况,对蚁群算法在最优路径的搜寻上从收敛性,收敛算法的改进以及收敛速度等方面的研究分别进行了分析综述,并对蚁群算法的一些应用,如:LEO卫星网络和无线传感等方面进行了阐述.对蚁群算法在路由优化和负载平衡上的研究进行了对比分析,发现了它们存在的不足,指出了在该领域需要进一步研究的热点问题.