基于Tinyos的无线温湿度传感器网络系统设计和实现     

钱开国  桑楠  马宏 《昆明师范高等专科学校学报》2008,30(4):30-32,40

集成了微机电(MEMS)系统、传感器技术、无线通信技术的无线传感器网络是一种全新的信息获取和处理方式,其应用前景非常广泛.设计和实现了无线温湿度传感器网络系统,其中包括硬件系统设计和Tinyos操作系统体系结构和应用程序的开发过程,给出了温湿度数据采集应用开发的要点.  相似文献   

移动自组织网络中QoS路由协议研究     

曹骞  侯加兵 《巢湖学院学报》2008,10(3):18-21

随着移动自组织网络(MANET)的应用领域日益扩大,要求它必须提供一定的服务质量(QoS)保证,而QoS路由协议是MANET支持QoS的一个关键理论和技术,也是目前的一个研究热点。本文对当前自组织网络的QoS主要路由协议进行了详细的分析与研究,并从路由机制、单向链路的支持、多播功能、QoS参数选择以及节能几个方面进行了比较和分析;最后指出了今后的研究方向。  相似文献   

基于多状态跳转模型的场景独立音频事件检测方法     

王健飞  张卫强  刘加 《中国科学院大学学报》2019,36(2):218-225

针对不同类型事件设计多状态跳转模型,结合两种深度神经网络实现对传统音频事件检测框架的改进。实验表明,在DCASE2017任务2的开发集数据上,改进后的DNN-HMM系统相比于基线系统取得F值8.9%的相对提升和错误率19%的绝对下降;基于多状态跳转模型聚类的卷积神经网络模型（SC-CNN）,相比于基线系统取得F值18%的相对提升和错误率30%的绝对下降。  相似文献   

Making American Friends: The Effects of Musical Tastes and English Proficiency on Chinese International Students’ Social Networks in the United States     

Fei Jia  Emmanuel Koku 《Journal of Intercultural Communication Research》2019,48(1):4-20

This study investigated the relationship between Chinese international students’ social networks in the United States and their musical tastes. Based on concept of homophily, this study used a self-reported Social Network Analysis (SNA) survey to examine whether sharing similar musical tastes affected Chinese international students’ relationship, their musical tastes, and music consumption. The results showed that having high musical taste similarity predicted closer relationship between respondents and their alters, and higher likelihood of new music consumption. This study also found that frequent American English-language songs listeners were more likely to have Americans in their social network than less-frequent American English-language songs listeners.  相似文献   

Reviewing the Variability-Overuse Injury Hypothesis: Does Movement Variability Relate to Landing Injuries?     

Andrew D. Nordin  Janet S. Dufek 《Research quarterly for exercise and sport》2019,90(2):190-205

Purpose: Overuse injuries are common in sport, but complete understanding of injury risk factors remains incomplete. Although biomechanical studies frequently examine musculoskeletal injury mechanisms, human movement variability studies aim to better understand neuromotor functioning, with proposed connections between overuse injury mechanisms and changes in motor variability. Method: In a narrative review, we discuss the variability-overuse injury hypothesis, which suggests repeated load application leads to mechanical tissue breakdown and subsequent injury when exceeding the rate of physiological adaptation. Due to the multidisciplinary nature of this hypothesis, we incorporate concepts from motor control, neurophysiology, biomechanics, as well as research design and data analysis. We therefore summarize multiple perspectives while proposing theoretical relationships between movement variability and lower extremity overuse injuries. Results: Experimental data are presented and summarized from published experiments examining interactions between experimental task demands and movement variability in the context of drop landing movements, along with comparisons to previous movement variability studies. Conclusion: We provide a conceptual framework for sports medicine researchers interested in predicting and preventing sports injuries. Under performance conditions with greater task demands, we predict reduced trial-to-trial movement variability that could increase the likelihood of overuse injuries.  相似文献   

有氧运动对慢性应激大鼠脑海马区神经可塑性的影响     

戈含笑  魏宏文  张有志  高颀  薛瑞  陈红霞 《北京体育大学学报》2017,40(5):39-45

摘要：目的：以神经元和神经胶质细胞相关神经生物学变化为切入点,探讨有氧运动对慢性应激大鼠脑海马区神经可塑性的影响。方法：以SD大鼠为研究对象,按照体重均衡分为对照组（CON）、慢性应激模型组（MOD）、氟西汀组（FLU）、低强度运动组（LIR）和中等强度运动组（MIR）。给予大鼠4周慢性应激,并分别伴随氟西汀给药、低强度或者中等强度的运动干预。4周后,通过开场实验、蔗糖饮水实验、新奇抑制摄食实验以及新物体识别实验检测运动对慢性应激大鼠抑郁样行为、焦虑样行为以及认知障碍的影响;同时,利用酶联免疫法和蛋白免疫印迹法,检测运动对慢性应激大鼠血清皮质酮、海马内前炎因子IL1-β,以及蛋白GFAP、S100β、BDNF、p-ERK、p-CREB表达的影响,探讨运动抗抑郁的行为学效应和作用机制。结果：1）低强度和中等强度运动能够显著增加慢性应激大鼠的开场活动、缩短新奇抑制摄食潜伏期,同时提高慢性应激大鼠新物体的识别指数;2）运动有效逆转了慢性应激大鼠血清皮质酮的异常升高,同时降低海马内前炎性因子IL1-β的分泌;3）运动可显著星形胶质细胞的标志性功能蛋白GFAP和S100β的表达水平,增强慢性应激大鼠的BDNF/ERK/CREB信号转导通路中重要蛋白BDNF、p-ERK、p-CREB的表达。结论：运动可以通过提高慢性应激大鼠脑海马区神经可塑性来达到抗抑郁的目的。可能与以下因素有关：1）运动调节血清皮质酮的异常升高,降低海马内前炎性因子的释放,同时,提高与神经胶质细胞相关蛋白GFAP和S100β活性,从而起到神经元保护的作用;2）运动可以通过激活CREB,BDNF以及ERK等重要信号蛋白的表达,提高神经营养作用,促进神经元的生长,增加神经可塑性和神经发生来发挥抗抑郁作用。  相似文献   

Notes to Contributors     

《Cultural and Social History》2013,10(4):533-534

ABSTRACT

Later eighteenth-century newspapers have been credited with shaping and reflecting readers' politics and growing sense of regional and national identity. However, historians have long ignored the role that newspaper proprietors played in the construction of those newspapers. Through a close study of one provincial proprietor, John Ware of Whitehaven, this article demonstrates that newspaper owners were shrewd operators in the public sphere. They were businessmen and women for whom the imagined community of readers was a real community of friends and business associates.  相似文献   

河北省人口老龄化趋势预测及对策研究     

王小春  王忠莉 《保定学院学报》2013,(3):26-30

运用Elman神经网络模型对2010—2050年河北省人口数进行预测,经过分析得出,河北省的人口老龄化具有以下几个特征:老年人口规模庞大,增长迅速;老龄化程度超前于河北省的经济发展水平,社会负担沉重;老年人口的高龄化趋势明显;老年人口的性别差异较大;老年人口的分布具有明显的差异性等。根据这些特征为河北省应对人口老龄化提供了一些对策建议。  相似文献   

基于遗传算法的新建给水管网优化设计     

栾志玲  纪志凤 《烟台职业学院学报》2007,13(3):47-52

遗传算法是一种较新的工程优化算法,将其引入给水管网优化设计,增强了管网设计方案的经济合理性。对给水管网优化设计的数学模型建立,遗传算法的基本原理、实数编码技术、评价函数的建立进行了分析,并用实例验证了其有效性。  相似文献   

基于神经网络的监控数据智能处理方法     

杨丽萍  胡雄  沈一飞 《上海海事大学学报》1997,(1)

针对船用系泊缆绳安全智能报警系统中的表格试验数据，提出了应用神经网络技术的智能数据处理方法。该方法克服了传统数据处理方法一般难以找到合适的逼近函数、处理过程复杂的弱点，避免了传统数据处理方法上的不便性和局限性，实现了表格数据非线性输入输出的映射。通过样本学习而建立的网络可以提高数据的取用效率，具有很大的灵活性和适用性。这是一种很有应用价值的数据处理方法。  相似文献