基于GSM网络的老年人身体姿态检测系统设计

论文设计了一套基于GSM(Global system for mobile communication,GSM)网络的老年人身体姿态检测系统,该系统以Cortex-M3系列STM32芯片为控制器模块、MMA7361加速度传感器为姿态检测模块、ATK-NEO-6M GPS为位置定位模块、GTM900C为信息发送模块,并运用卡尔曼滤波和支持向量机算法检测老年人跌倒行为。实验结果表明,该系统能准确判断人体正常活动与跌倒事件,能自动定位并发送短消息。     

车载定位导航终端的设计

设计了一种GSM/GPRS的车载定位导航终端.该终端基于先进的SOC技术,开发了单片机IP核中内嵌的特定功能,利用单片机的内置闪存ROM技术扩展系统存储空间,实现大量定位信息的存储,并设计了串口扩展电路、GPS模块和GSM/GPRS模块的双模控制等电路.介绍了车载终端的硬件和软件设计以及实现方法.实践证明:在实际的定位导航过程中,该终端具有较高的灵敏度、精确度和强大的信息处理能力.     

BD-2/GPS组合系统的设计与定位算法

目前世界上4大主力卫星导航定位系统的兼容技术日益提高和完善,在这种客观需求下使多系统联合定位成为可能。为达到两种系统组合定位的目的,将中国北斗二号(BD-2)与GPS技术相融合,在BD-2单系统定位原理的基础上提出了BD-2/GPS构成的组合接收系统的设计思路和BD-2/GPS组合导航定位系统的数学解算方法。在定位算法上采用了加权最小二乘法对组合导航定位系统进行解算,并通过MATLAB软件对数据结果进行计算和分析,证明了此种算法的可行性和可靠性。     

基于GPS/BD-2的军队车辆监控系统设计

针对军队中如何对军车进行有效监控和调度,提高战时物资投递效率的问题,提出了一种基于GPS/BD-2的军队车辆监控系统的设计。该系统采用信息化手段,依托北斗二代和GPS组合定位系统,设计了GPS/BD-2车载终端、信息处理服务器和指挥调度终端三部分,实现了车辆身份与入网管理、车辆管理、车辆监控、报警管理、统计查询、系统管理等业务需求。本系统提供更加精准的定位服务,满足了信息化条件下军队车辆保障的需求,促进部队车辆建设安全、科学发展。     

可用于智能养老院系统终端的电路设计

提出了一种基于MSP430单片机与NRF24L01+射频无线通信技术的可用于智能养老院系统终端的电路设计方案。该系统实现了以下功能:能够识别老人身份、紧急呼叫、摔倒报警、老人监控与定位。电路采用模块化设计,分别从电源管理模块、核心控制模块、射频无线通信模块、防摔倒模块、GSM通信与GPS人员定位模块这五方面描述了整个电路系统的硬件设计。经实际调试运行表明,识别距离可高达100m,且使用方便、稳定可靠、实用性强,具有很好的市场推广应用价值。     

多功能北斗智能手杖的研究与设计

随着中国逐渐进入老龄化社会阶段,老年人群的安全管理问题已成为社会的热点问题。为了实现对老人的全方位监管,研究设计了基于北斗定位与定时功能的多功能北斗智能手杖。利用Pulse Sensor心率传感器以及GY-MCU90615红外体温传感器分别对老人的心率、体温进行实时监测;利用超声波测距模块HC-SR04以及九轴模块MPU-9250对老人当前的移动状态进行判断;利用GPS/BDS双模定位模块对老人进行空间与时间上的准确定位和时间同步;利用GSM无线通信模块将老人的心率、体温、移动状态、时间信息以及空间定位信息发送给通过Android设计的手机终端监控软件。文中研究了该系统的软硬件设计,同时给出了实验测试结果,结果表明：该系统可以精确地获取老人的时空信息以及健康信息并将这些信息实时传递给远程的手机终端监测软件。相比于现有的智能化手杖,在跌倒识别、生理监测以及手机软件开发方面具有其独特的优势。本研究对实现老人的安全管理具有一定的意义。     

远程血液冷链运输监测系统设计

为了解决血液冷链运输的安全问题,设计了一套放置在车厢内的远程血液冷链运输监测系统。该系统通过ZigBee网络实时采集车厢内的环境数据并发送到STM32微控制器,然后对采集到的运动状态数据进行了详细分析处理。STM32微控制器接入了GPS/BDS双定位模块和GPRS无线通信模块,其中GPS/BDS双定位模块可以对当前车辆的地理位置进行定位。车厢内的环境数据、车辆地理位置数据和报警信息通过GPRS模块传送到远程后台监控中心的上位机存储并实时显示。系统功能测试表明该系统具有准确性、高可靠性和高适用性等特点。     

基于GPRS/3G的远程通信实验系统组网方案实现

针对远程通信实验对于系统组网的要求,提出了一种基于GPRS/3G技术的系统组网方案。系统设有多个外置的GSM模块,中心和远程设备通过串口控制各自的模块,以实现网络连接和SMS通信,传递实验数据和各设备定位信息。对方案中GSM模块、GPS模块及其附属电路、GPRS网络连接和短消息编码方式等关键技术进行了介绍,并给出了软件流程图和VC实现的部分代码。     

一种适用于单片机的老人跌倒检测算法研究

针对单片机的计算能力和检测系统的实时性,设计了一种可穿戴的老人跌倒检测装置。利用六轴陀螺仪加速度计进行原始信号的采集,将合成加速度和姿态角作为特征量,设计一种基于二叉树支持向量机分类思想的三级检测算法。首先,以合成加速度是否超出阈值作为分类条件,识别样本是否属于剧烈运动;其次,则以合成加速度是否呈现周期性变化和人体是否处于类静止状态(合成加速度在0.8~1.2 g)将样本进一步细分;最后,则通过判断人体的姿态确定老人是否跌倒。当检测到老人跌倒后,利用GPS对老人进行定位,同时利用GSM模块发送报警信息。实验证明算法准确率高、实时性好。同时能够准确定位,并将信息发送出去。     

基于北斗/GPS的城市公共自行车管理系统设计

为了提高公共自行车管理系统的便利性水平和功能性水平,本文研究并设计了一套基于北斗/GPS定位的城市公共自行车管理系统.该系统由安卓(Android)手机终端、服务器端和车载终端组成.车载终端以单片机(MCU)为主控芯片,并采用北斗定位模块、GSM/GPRS模块及按键模块进行公共自行车运行状态的监测及远程通信.本设计能够实现车辆查找、空位查询、损坏报修、车辆定位、车辆管理、信息登记等功能.实际测试表明,该系统具有运行稳定、装配简易、操作便利和功能丰富的特点,同时还可为城市公共自行车分布规划提供数据支持,具有较好的推广前景.     

Morphological and electrical characterization of SixCryCzBv thin films

Si_xCr_yC_zB_v thin films with several compositions have been studied for integration of high precision resistors in 0.8 μm BICMOS technology. These resistors, integrated in the back-end of line, have the advantage to provide high level of integration and attractive electrical behavior in temperature, for analog devices. The film morphology and the structure have been investigated through transmission electron microscopy analysis and have been then related to the electrical properties on the base of the percolation theory. According to this theory, and in agreement with experimental results, negative thermal coefficient of resistance (TCR) has been obtained for samples with low Cr content, corresponding to a crystalline volume fraction below the percolation threshold.Samples with higher Cr content exhibit, instead, a variation of the TCR as a function of film thickness: negative TCR values are obtained for thickness lower than 5 nm, corresponding to a crystalline volume fraction below the percolation threshold; positive TCR are obtained for larger thickness, indicating the establishment of a continuous conductive path between the Cr rich grains. This property seems to be determinant in order to assure the possibility to obtain thin film resistors almost independent on the temperature.     

Current-voltage characteristics of GaAs p-i-n and n-i-n diodes

Using the same basic equations as Kazarinov et al.[2], but assuming that the product of the electron drift velocity and of the electron lifetime remains constant, we have derived a new formula for the forward d.c. current—voltage characteristic distinguished by the saturated voltage. We have shown that this formula can describe the measured characteristics of some GaAs p-i-n and n-i-n diodes.     

Pentacene/n-Si heterojunction diodes and photovoltaic devices investigated by I-V and C-V measurements

The forward and reverse current density-voltage (J-V) and capacitance-voltage (C-V) characteristics of pentacene/n⁻-silicon heterojunction diodes were investigated to clarify the carrier conduction mechanism at the organic/inorganic heterojunction. Current rectification characteristics of the pentacene/n⁻-Si junctions can be explained by a Schottky diode model with an interfacial layer. The diode parameters such as Schottky barrier height and ideality factor were estimated to be 0.79-1.0 eV and 2.4-2.7, respectively. The C-V analysis suggests that the depletion layer appears selectively in the n⁻-Si layer with a thickness of 1.47 μm from the junction with zero bias and the diffusion potential was estimated at 0.30 eV at the open-circuit condition. The present heterojunction allows the photovoltaic operation with power conversion efficiencies up to 0.044% with a simulated solar light exposure of 100 mW/cm².     

Traffic and /spl lambda/ grooming

The article gives an overview of traffic grooming and lambda grooming in multilayer networks, and discusses the advantages and drawbacks of these methods as well as applications and future alternative directions.     

Comparison between Pt/TiO2/Pt and Pt/TaOX/TaOY/Pt based bipolar resistive switching devices

Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices. In this article, the performances of TiO₂ and TaO₂ nonvolatile memristive devices were compared and the factors that make TaO₂ memristive devices better than TiO₂ memristive devices were studied. TaO₂ memristive devices have shown better endurance performances (10⁸ times more switching cycles) and faster switching speed (5 times) than TiO₂ memristive devices. Electroforming of TaO₂ memristive devices requires~4.5 times less energy than TiO₂ memristive devices of a similar size. The retention period of TaO₂ memristive devices is expected to exceed 10 years with sufficient experimental evidence. In addition to comparing device performances, this article also explains the differences in physical device structure, switching mechanism, and resistance switching performances of TiO₂ and TaO₂ memristive devices. This article summarizes the reasons that give TaO₂ memristive devices the advantage over TiO₂ memristive devices, in terms of electroformation, switching speed, and endurance.     

Effect of BaCeO/sub 3/ and BaSnO/sub 3/ additives on microstructural development and critical current density of melt textured YBa/sub 2/Cu/sub 3/O/sub 7-x/

Improvement of superconducting properties, such as critical current density J/sub c/ and trapped magnetic field, of melt textured YBa/sub 2/Cu/sub 3/O/sub 7-x/ (Y123) require introducing of effective pinning sites, e.g., nonsuperconducting inclusions, twin boundaries and other defects. It has been shown that addition of small quantities of BaCeO/sub 3/ (<0.5 wt%) into Y123 results in an increase of the J/sub c/. However, higher cerium concentrations affect the solidification process and inhibit the growth of melt textured Y123 single crystals. In this study, the effect of BaCeO/sub 3/ additions on the growth and microstructural development of melt textured Y123 single crystals were investigated. The relationship between the solidification kinetics, microstructural development and superconducting properties of Y123 melt textured single crystals with cerium additives is discussed.     

Long-wavelength In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As large-area avalanche photodiodes and arrays

Large-area (500-/spl mu/m diameter) mesa-structure In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiodes (APDs) are reported. The dark current density was /spl sim/2.5/spl times/10/sup -2/ nA//spl mu/m/sup 2/ at 90% of breakdown; low surface leakage current density (/spl sim/4.2 pA//spl mu/m) was achieved with wet chemical etching and SiO/sub 2/ passivation. An 18 /spl times/ 18 APD array with uniform distributions of breakdown voltage, dark current, and multiplication gain has also been demonstrated. The APDs in the array achieved 3-dB bandwidth of /spl sim/8 GHz at low gain and a gain-bandwidth product of /spl sim/120 GHz.     

Annealing effect on physical and electrical characteristics of thin HfO2, HfSixOy and HfOyNz films on Si

We report the effect of annealing on electrical and physical characteristics of HfO₂, HfSi_xO_y and HfO_yN_z gate oxide films on Si. Having the largest thickness change of 0.3 nm after post deposition annealing (PDA), HfO_yN_z shows the lowest leakage current. It was found for both as-grown and annealed structures that Poole-Frenkel conduction is dominant at low field while Fowler-Nordheim tunneling in high field. Spectroscopic ellipsometry measurement revealed that the PDA process decreases the bandgap of the dielectric layers. We found that a decreasing of peak intensity in the middle HfO_yN_z layer as measured by Tof-SIMS may suggest the movement of N toward the interface region between the HfO_yN_z layer and the Si substrate during the annealing process.     

1/spl times/2 and 1/spl times/4 electrooptic switches

We describe the design, fabrication, and testing of two packaged electrooptic switches built from poled LiTaO/sub 3/ crystals. The 1/spl times/2 switch requires a driving voltage of 1200 V and exhibits insertion loss of 2.4 dB and crosstalk of -39.2 dB; the 1/spl times/4 switch exhibits insertion loss and crosstalk of 2.8 dB and -40.6 dB, respectively, and operates using a 1100-V voltage source. The maximum deflection time between the channels is 86 ns.