Ergonomic Analysis of Mobile Cart–Assisted Stocking Activities Using Electromyography

Workers in grocery stores are exposed to numerous musculoskeletal risks that can be reduced using assistive devices while performing stocking tasks. A regional grocery store has recently deployed a mobile cart without comprehension of its ergonomic impact on workers, which this article investigates using normalized electromyography data (%MVC). This article studies not only ergonomic impact based on %MVC values but also work performance represented by a muscle force metric (MFM). The results from this study showed highest muscle groups in %MVC and MFM were the erector spinae and triceps. Interestingly, muscle activations on erector spinae were reduced when mobile cart is used. %MVC and MFM distribution for value‐added‐ and non‐value‐added subtasks were slightly different, with larger differences observed for non‐value‐added tasks. Video recordings revealed higher work performance when the mobile cart is used. In future research, the number of participants will be increased to further validate the results from this study.     

Novel neural network modeling method and applications

Neural networks play an important role for designing the parametric model of electromagnetic structures. The current neural network methods are unfit for a circuit model with many input variables because it is costly to extract a large number of the training data and test data to complete the highly nonlinear mapping approximation. This article proposes a new neural network modeling method—the multidimensional neural network model, which can be used to solve the issue of multivariable radiofrequency and microwave passive device modeling. The entire multidimensional neural network modeling problem is simplified into a set of neural network submodels through decomposition method. Then the submodels are combined into an equivalent model, and the final entire model is produced through the neural‐network mapping model developed with the submodels and equivalent model. A microstrip hairpin filter model is developed using the proposed method. The simulation results show the correctness and the effectivity of the proposed method. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:769–779, 2015.     

Parametric Stabilization of Quantized Interconnected Systems with Application to Coupled Inverted Pendulums

This paper studies the analysis of parametric stability and decentralized state feedback control of a kind of quantized interconnected systems. The output of each controller is quantized logarithmically before it is input to the subsystem, and the quantized density would affect the stability of the systems. First, a decentralized state feedback controller is designed for interconnected systems without quantization and the corresponding stable region is obtained. Second, for a given controller, the lower bound of the quantization density is evaluated from parameters of local controllers. Finally, the proposed method is applied to coupled inverted pendulums systems which can be viewed as quantized interconnected systems. The simulation results show that by using the proposed quantized controllers, the interconnected inverted pendulum systems are parametrically stabilized.     

矿井物流管理和人员定位系统数据库设计

针对矿井物流管理系统与矿井人员定位系统独立运行导致的成本高、维护困难等问题,提出将2个系统进行相互融合、统一管理的方式,并采用射频识别技术和Microsoft SQL Server 2008数据库软件,设计了一种矿井物流管理和人员定位系统,着重介绍了需求分析及逻辑结构设计阶段的系统数据库设计方案,并给出了主要运输流程数据库表的映射关系。该数据库逻辑结构简单、清晰,具有良好的存储结构、数据共享性和一致性。实际应用表明,该数据库具有较高的实用性和可靠性。     

Research on social relations cognitive model of mobile nodes in Internet of Things

Interaction and communication between humans with smart mobile devices are a new trend of development in Internet of Things (IoT). With the powerful sensing capability of smart device and human mobility, various services could be provided by building a trusted chain between service requesters and suppliers. The cognition of social relations between mobile nodes is the basis of final mobile-aware services. It involves many decision factors, such as time, space and activity patterns. Using social network theory, a new cognitive model for social relations of mobile nodes in IoT is proposed. Firstly, nodes' social relations are reasoned and quantified from multiple perspectives based on the summary of social characteristics of mobile nodes and the definition of different decision factors. Then the location factor, interconnection factor, service evaluation factor and feedback aggregation factor are defined to solve the shortcomings in existing quantitative models. Finally, the weight distribution is set up by information entropy and rough set theory for these decision factors; it can overcome the shortage of traditional methods, in which the weight is set up by subjective ways and hence their dynamic adaptability is poor. We compare our cognitive model to existing models using MIT dataset by defining a variety of test indicators, such as network overall density (NOD), the degree center potential (DCP), the network distribution index (EI), etc. Simulation results show that, the cognitive model has better internal structure and significant validity in network analysis, and thus can provide mobile-aware service effectively in dynamic environment.     

芙蓉江清溪水电站发电引水系统设计及施工优化

贵州芙蓉江清溪水电站发电引水工程由于受地形、地质条件及设计方案限制,其施工工期在工程总进度计划中为控制性关键线路.由于采纳了作者的优化建议,对设计方案和施工布置进行了适当优化,实际施工中不仅提前完成了该项工程,有效地避免了施工干扰,还节省了工程投资,取得了较好的社会效益及经济效益.     

工学结合在高职计算机专业教学改革中的研究

"工学结合,校企合作"是中国这几年来职业教育发展进程中最具特色、最突出的办学经验,笔者结合自己实际教学,从教学面临的问题、解决方案、取得的成效等方面提出了一些具体的改进措施和建议,以促进和加强计算机专业学生的职业能力和职业素质的培养。     

基于FPGA分布式算法的滤波器设计

研究基于分布式算法的数字滤波器设计方法,介绍了能高效实现固定常数乘法的分布式算法原理,并将分布式算法应用于FIR低通滤波器设计,实现了16阶滤波器的设计和调试.采用了EP3C25F324C8来完成滤波器的设计,其中采用串行加法器将数据进行预相加,将16阶降为8阶,降低了资源占用率并提升了处理速度.使用Matlab编程8阶固定常数系数对应256个值的查找表直接导入到FPGA的ROM中,设计方法具有兼容性,可设计更高阶次的滤波器.通过功能仿真证明,方法可行高效.     

Existence and global exponential stability of periodic solutions of recurrent cellular neural networks with impulses and delays

By using the continuation theorem of coincidence degree theory and constructing suitable Lyapunov functions, we study the existence, uniqueness and global exponential stability of periodic solutions for recurrent neural networks with impulsive perturbations and delays. Further, by using numerical simulation method, the influences of the impulsive perturbations on the inherent oscillations are investigated.     

VR仿真平台在自动化仓储系统中的设计与实现

针对自动化仓储系统的构建及运行特点,设计一种基于虚拟现实(VR)技术的仿真平台。阐述该平台的设计思想和实现手段,根据仓库运行方式的离散化,研究立体仓库堆垛机的路径优化方法,完成对算法的仿真分析。以一个仿真实例展现系统仿真平台的沉浸感、交互性和构想力,验证了其可行性。