基于倒立摆的便捷自动控制教学平台的研究与设计     

赵燕  王江华  郭海文 《大众科技》2015,(1):15-17

设计一基于倒立摆的便捷自动控制教学平台,内置三维陀螺仪、加速度计等传感器,可实现平台的自主直立控制。平台利用STM32单片机对陀螺仪的角速度和加速度计的加速度进行实时跟踪,采用卡尔曼滤波算法对陀螺仪与加速度计采集回来的姿态信号进行校正,从而得到一个准确的空间姿态;通过采集编码器产生的脉冲来计数,形成速度闭环控制,实现双轮自平衡教学平台在任何干扰情况下,均能保持直立平衡状态。该教学平台的特点在于体积小巧,携带方便,操作简单,运行可靠,调整速度快。该平台是一个可随堂演示的PID控制系统,采用现场实物演示将大大增添课堂趣味性,学生们学习相关理论知识时将会更加积极主动,从而提高理论教学的质量。  相似文献   

LED点阵书写显示屏设计     

周莹  张海燕 《重庆职业技术学院学报》2010,19(3):155-157

本文介绍了基于32×32点阵LED书写显示屏的设计方法,给出其硬件电路原理图和软件流程图。设计以单片机AT89C52为控制芯片,使点阵显示屏工作在人眼不易觉察的微亮扫描模式和人眼可见的点亮显示模式下,通过光笔对接触点的行列坐标检测,可在显示屏上相应位置实现＂点亮＂、＂划亮＂、＂反显＂和＂整屏擦除＂等功能。系统采用双机通信的方式,具有显示清晰、响应速度快、可靠性高等特点。  相似文献   

基于 Cortex-M3的 GSM 短信报警系统设计     

陈康伟  王健  钟波 《大众科技》2012,(5):1-3,24

系统以 Cortex-M3为内核的 STM32单片机来控制 GSM 模块及热释电传感器模块,并应用于家庭防盗报警系统中.SIM900A 模块是一款尺寸紧凑的 GSM/GPRS 模块,能支持中文短信息,该模块集射频电路和基带于一体,向用户提供标准的 AT命令接口.STM32单片机具有低功耗、高性能的特点.红外专用芯片 BISS0001设计的人体传感模块能以非接触方式检测出来自人体发出的红外辐射,并将其转化成电信号输出.结合以上芯片,附加扬声器报警可达到家庭智能防盗的目的.  相似文献   

What hampers innovation? Revealed barriers versus deterring barriers   总被引：1，自引：0，他引：1  

Pablo D’Este  Simona Iammarino  Maria Savona  Nick von Tunzelmann 《Research Policy》2012,41(2):482-488

Innovating firms are likely to face several challenges and experience different types of barriers. In this paper we argue that it is necessary to distinguish between two kinds of barriers to innovation. The first corresponds to what we describe as revealed barriers and reflects the degree of difficulty of the innovation process and the learning experience consequent on the firm engaging in innovation activity. The second type of impediment, which we label deterring barriers, encompasses the obstacles that prevent firms from committing to innovation. We use data from the 4th UK Community Innovation Survey (CIS4) to investigate the relationship between firms’ engagement in innovation and their assessment of the barriers to innovation. We show that the relationship is curvilinear in the case of costs and market barriers. These results have important implications for innovation policy and innovation management.  相似文献   

Do R&D subsidies affect SMEs’ access to external financing?     

Miguel Meuleman  Wouter De Maeseneire 《Research Policy》2012,41(3):580-591

Many countries spend sizeable sums of public money on R&D grants to alleviate debt and equity gaps for small firms’ innovation projects. In making such awards, knowledgeable government officials may certify firms to private financiers. Using a unique Belgian dataset of 1107 approved requests and a control group of denied requests for a specific type of R&D grant, we examine the impact of subsidies on small firms’ access to external equity, short term and long term debt financing. We find that obtaining an R&D subsidy provides a positive signal about SME quality and results in better access to long-term debt.  相似文献   

The temporal trajectories of innovative search: Insights from public hospital services     

Torsten Oliver Salge 《Research Policy》2012,41(4):720-733

This article explores the temporal trajectories of innovative search. Drawing on conceptual ideas from the behavioural theory of the firm, it proposes that the level of temporal persistence in organisations’ innovative search activities is affected by four key factors. These include (i) the mode of innovative search as well as organisations’ (ii) strategic aspirations, (iii) slack resources and (iv) performance feedback. This conceptual model is tested in the context of public hospital services in England. Results from dynamic panel data analyses reveal stronger temporal persistence in science- than in practice-based innovative search activities. Findings also suggest that specialist hospitals relying on a continuous stream of new products, services and processes to meet their strategic aspirations are better positioned to sustain science-based innovative search activities than their generalist counterparts. Similarly, results uncover a positive association between the availability of financial slack and hospitals’ ability to continuously engage in superior levels of science-based innovative search. Contrary to theoretical expectations, however, positive performance feedback does not appear to have any persistence-enhancing effect.  相似文献   

Tax incentives and R&D activity: Firm-level evidence from Taiwan     

Chih-Hai Yang  Tony Chieh-Tse Hou 《Research Policy》2012,41(9):1578-1588

This paper investigates the effect of tax incentives on R&D activities in Taiwanese manufacturing firms. The propensity score matching (PSM) estimates show that recipients of R&D tax credits appear on average to have 53.80% higher R&D expenditures than that they do without receiving tax credits, while there is no significantly higher growth rate of R&D expenditure. This study further employs the panel instrumental variable (IV) and generalized method of moment (GMM) techniques to control for endogeneity of R&D tax credits and firm heterogeneity in determining R&D expenditure. The R&D tax credit is witnessed to exhibit a significantly positive influence on R&D expenditure and its growth, especially for electronics firms. The marginal effect is moderate, ranging from 0.094 to 0.120. Specifically, the R&D elasticity concerning tax credits tends to increase gradually along with the approaching expiration of R&D tax credits measure, lending a supportive view on its efficacy.  相似文献   

基于STM32F103X系列单片机的智能游客寻呼系统     

李寒生  黄卫红 《教育技术导刊》2014,13(11):136-138

在旅行期间,为确保游客安全,导游在游客游览过程中特别是景点换乘时总要不时点名,以防止游客走散和丢失。依托单片机、射频技术以及GPRS无线通信技术,设计了一种游客智能点名寻呼系统,极大地提高了导游的工作效率和服务水平。  相似文献   

基于STM32的USBTMC协议的研究与实现     

陈一鸣  高云  邓攀  尚伦  陈雪艳 《武汉工程职业技术学院学报》2014,(2):42-45

研究解析了USBTMC协议,并在基于ARM Cortex-M3内核的STM32微控制器上实现了符合USBTMC协议的USB设备。利用VISA和labVIEW软件对USB设备进行测试,结果表明USB设备数据传输速度快、可靠性高、开发简便。  相似文献   

Intangible assets and firm heterogeneity: Evidence from Italy     

Alessandro Arrighetti  Fabio Landini  Andrea Lasagni 《Research Policy》2014

The positive impact of intangible assets on several measures of economic performance is well documented in the literature. Less clear is what initially leads firms to invest in intangible assets. The latter is particularly important because, at least for the Italian manufacturing sector, firms exhibit strong heterogeneity in their investments in intangible assets. In line with the capability-based theory of the firm, we argue that the firm's propensity to invest in intangible assets can be explained by factors that are internal and specific to the firm. Making use of a rich dataset, we test and provide support for our hypotheses. In particular, we find that the propensity to invest in intangible assets increases with the firm's size, human capital, and historical intangible asset base. This points towards the existence of a cumulative process of intangible asset accumulation, which may account for most of the heterogeneity observed in the data. The paper adds to the previous literature in two ways: first, it highlights the existence of strong intra-industry heterogeneity in intangible asset investments, and second, it offers an explanation for such heterogeneity.  相似文献