Parameters affecting pre-cooling, freezing, storage and transport of red raspberry fruits, individually frozen in discontinuous tunnels. Comparison among five varieties of Rubus sp.

Red raspberry is a fruit of very low mechanical resistance even in the frozen state. Due to this a series of problems in harvesting, pre-cooling, freezing, frozen storage and refrigerated transport take place. Previously developed methodology is applied in this work according to the above-mentioned characteristic for five varieties of red raspberry fruit. Practical parameters, such as pre-cooling times, weight loss, individually frozen fruit%, critical temperatures of storage and refrigerated transport, etc., are recommended for their handling and for improving the individually frozen fruit yields, so that the final quality of the product is not affected by non appropriate handling.     

基于NodeMCU智能语音交互家居系统设计

针对传统家居家电设备很难直接与市场上的语音助手结合,同时高技术产品价格很难惠民,智能家居控制系统因设计成本过高很难实现普及的现象,本文提出将树莓派和NodeMCU开发板联合开发一款性价比极高的智能语音交互家居系统。设计使用树莓派4B+在Linux系统下运行百度云平台提供的SDK加上麦克风阵列和CSI摄像头实现语音识别、语音合成和人脸识别等功能。利用Python serial库实现与Arduino串口通信,树莓派将语音识别到的指令下发至Arduino,从而实现人与硬件设备语音交互。NodeMCU通过内置ESP8266芯片使用Arduino IDE编译将传感器采集到的数据通过TCP协议与物联网云平台连接,实现数据的远程存储,家庭环境信息的远程观测和远程控制。运行结果显示,实现家居环境数据无线传输与语音交互的功能要求,设计成本低廉,功能强大且扩展方便。本系统实现了多平台交互,提高了多任务并行处理能力。     

IPv6校园数据中心环境监测系统研究

随着高校信息化技术的发展,传统数据中心的运维模式已不能满足现代需求,智能化数据中心环境监控平台的建设已成为迫切需求;而且现阶段的数据采集终端多基于51单片机、STM32单片机等平台,在一定程度上终端不具有智能化,故该系统平台采用树莓派对数据中心环境进行监测采集。同时随着接入互联网终端越来越多,IPv4地址资源池已经匮乏,采用IPv6组网技术对数据中心环境进行监测,不仅能有效地解决IPv4地址资源不足的问题,而且结合树莓派丰富的接口功能,扩展了环境监测的平台功能多样性。     

用Pi演算为业务过程建模的生命周期

随着企业竞争日趋激烈,业务过程建模技术变得越来越重要.由于形式化方法降低了二义性并为模型的分析和验证提供了可行性,因此形式化的业务过程建模技术在学术界引起了很多人的关注,但到目前为止仍缺乏一套既能方便地进行过程建模,又具有对模型进行形式化分析与验证的整套理论体系.从生命周期的角度入手,探讨如何把形式化方法更有效地应用于商业过程建模.主要工作在于提出了基于Pi演算的生命周期,探讨了生命周期各个阶段使用的技术和工具.     

电池管理系统的报文采集与解析

电池管理系统(BMS)主要功能是实时监控、管理动力电池组中各单体电池的正常工作, 电池的各项信息被BMS以CAN报文的形式发出. 通过采集和解析BMS的报文, 能够对电池的性能作进一步分析评测. 本文以树莓派为载体, 通过设计树莓派的扩展板实现CAN报文的采集, 同时在树莓派中解析CAN协议的DBC文件格式. 设计了一款可移动便携式的CAN报文采集与解析设备, 并根据电池组所有电芯开路电压的解析数据对电池一致性做出快速评估.     

Coupling of Pi2 wave energy in the inner magnetosphere as inferred from low-latitude ground observations

Taking advantage of high time-resolution (1 s) geomagnetic field measurements obtained at low-latitude stations, we investigated frequency differences of Pi2 pulsations between the dayside and the nightside. Firstly, we examined two Pi2 cases globally observed by multiple ground stations and found that the dominant frequency peaks at the dayside showed latitudinal dependence, i.e., the higher (lower) frequency peak was predominant at lower (higher) latitude. We also noticed that the dominant Pi2 frequency on the nightside was apparently higher than that on the dayside. We argue that the multiple frequency peaks observed on the ground are harmonics of a plasmaspheric cavity resonance mode (CRM) and that the latitudinal dependence of the dominant frequency peaks may result from the energy coupling between the CRM and field line resonance (FLR) occurred in the near Earth space. We also argue that the frequency difference between the dayside and the nightside could be caused by the reason that a higher harmonic was observed in the nightside plasmasphere but was not effectively observed in the dayside. In addition, we statistically examined 829 Pi2 events that were simultaneously recorded at Kakioka (KAK, Maglat=27.2°) and Jicamarca (JIC, Maglat=0.0°), the two stations separated by ～10 h in local time (LT) and one of them (JIC) is located at the dip equator. We found that the Pi2 frequency observed at KAK on the nightside was higher than that observed at JIC on the dayside on average. After investigating the occurrence histogram of the frequency difference (Δf=f _JIC?f _KAK) for the events simultaneously observed at KAK and JIC, we found that close to half of the events had the identical frequency (|Δf|<1.0 mHz). The statistical results are consistent with the facts reflected by case studies.     

Ordered fields and {{{\rm \L}\Pi\frac{1}{2}}} -algebras

In this work we further explore the connection between -algebras and ordered fields. We show that any two -chains generate the same variety if and only if they are related to ordered fields that have the same universal theory. This will yield that any -chain generates the whole variety if and only if it contains a subalgebra isomorphic to the -chain of real algebraic numbers, that consequently is the smallest -chain generating the whole variety. We also show that any two different subalgebras of the -chain over the real algebraic numbers generate different varieties. This will be exploited in order to prove that the lattice of subvarieties of -algebras has the cardinality of the continuum. Finally, we will also briefly deal with some model-theoretic properties of -chains related to real closed fields, proving quantifier-elimination and related results.     

基于Raspberry Pi的家庭健康监测网关

随着人口老龄化和亚健康人群的增多,人们对健康监测服务的需求也不断增加.心率、血压、血糖等生理数据中包含了人体健康状况的重要病理信息,为接收和预处理这些生理数据,并完成对生理检测设备的集中管理和数据的自动采集,本文基于Raspberry Pi （树莓派）研究开发了一个家庭健康监测网关.该家庭健康监测网关,通过蓝牙通讯获取生理检测设备的数据,并进行存储或利用无线网络将其传输至服务器.最后,以监护对象的心电数据采集、传输及展示过程为例,对系统整体进行功能性测试.该网关为家庭健康监测提供了可行的方案,在减轻社会医疗压力方面具有重要意义.     

An Embedded Solar‐Powered Irrigation System Based on a Cascaded Fuzzy Logic Controller

This study examines the automatization of irrigation tasks of solar photovoltaic water pumping systems (SPVWPS) in greenhouse applications. A prototype of an embedded control system has been developed for SPVWPS battery‐coupled architectures. The new design aims at improving the safety of solar irrigation facility by avoiding the exhaustion of pumping resources (water and energy) while watering. The availabilities of pumping resources are introduced as new requisite inputs of a fuzzy logic‐based control system (FLC) so that it can produce adequate and safe irrigation durations. The FLC design consists of two cascaded devices. The first device uses climate data to estimate durations for watering that satisfy crop needs. The second device uses actual resource levels to evaluate the pumping capacity of the SPVWPS regarding requested durations. Watering is performed whenever the pumping capacity of the system represents more than 25% of the total requirement. Test results from an experimental greenhouse prove the effectiveness of the decision‐making mechanism that prevents scheduling unsuccessful watering tasks.     

Ethernet based time synchronization for Raspberry Pi network improving network model verification for distributed active turbulent flow control

Friction drag primarily determines the total drag of transport systems. A promising approach to reduce drag at high Reynolds numbers(> 104) are active transversal surface waves in combination with passive methods like a riblet surface. For the application in transportation systems with large surfaces such as airplanes, ships or trains, a large scale distributed real-time actuator and sensor network is required. This network is responsible for providing connections between a global flow control and distributed actuators and sensors. For the development of this network we established at first a small scale network model based on Simulink and True Time. To determine timescales for network events on different package sizes we set up a Raspberry Pi based testbed as a physical representation of our first model. These timescales are reduced to time differences between the deterministic network events to verify the behavior of our model. Experimental results were improved by synchronizing the testbed with sufficient precision. With this approach we assure a link between the large scale model and the later constructed microcontroller based real-time actuator and sensor network for distributed active turbulent flow control.