The VEGA Venus Balloon Experiment

In June 1985, two instrumented balloons were placed in the atmosphere of Venus as part of the VEGA mission. Each balloon traveled about 30 percent of the way around the planet at a float altitude near 54 kilometers. In situ sensors measured pressure, temperature, vertical wind velocity, cloud particle backscatter, ambient light level, and frequency of lightning. A ground-based network of 20 radio antennas tracked the balloons by very long baseline interferometry (VLBI) techniques to monitor the Venus winds. The history, organization, and principal characteristics of this international balloon experiment are described.     

Sugarbeet Yield Monitoring for Site-Specific Farming Part II–Field Testing

A field study was conducted to evaluate three real-time weighing systems to measure sugarbeet yield. Two systems permit use of the storage hopper onboard the harvester. The effects of tare on yield measurement were investigated. Parallel yield data from the three systems were compared. There was a strong relationship between systems as sugarbeet flow rates changed. High standard deviations were found for all product flow sensors. There was no statistical difference between two of the sensors, but there was for the other. One system provided unacceptable results. One of the systems provided reasonable accuracy and permitted use of the onboard storage hopper.     

基于无线和短信环境安全型猪舍监控技术研究

通过无线和短信结合,实现了对环境安全型猪舍的监控。系统由无线智能传感器、无线或短信通信终端、监控中心和执行节点四部分组成,采用集散控制方法。监控中心是整个系统的核心,对数据进行集中管理、分析和处理,其他部分负责数据采集、传输和执行。     

Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons

A global array of 20 radio observatories was used to measure the three-dimensional position and velocity of the two meteorological balloons that were injected into the equatorial region of the Venus atmosphere near Venus midnight by the VEGA spacecraft on 11 and 15 June 1985. Initial analysis of only radial velocities indicates that each balloon was blown westward about 11,500 kilometers (8,000 kilometers on the night side) by zonal winds with a mean speed of about 70 meters per second. Excursions of the data from a model of constant zonal velocity were generally less than 3 meters per second; however, a much larger variation was evident near the end of the flight of the second balloon. Consistent systematic trends in the residuals for both balloons indicate the possibility of a solar-fixed atmospheric feature. Rapid variations in balloon velocity were often detected within a single transmission (330 seconds); however, they may represent not only atmospheric motions but also self-induced aerodynamic motions of the balloon.     

nRF401在大棚温度监控中的应用

应用基于蓝牙技术的无线收发芯片nRF401,研究了大棚温度监控中信号的无线传输技术和实现方法.阐述了无线收发芯片nRF401的特点及性能指标,并通过nRF401无线通信模块进行无线实时监控的监测系统.系统利用单片机同时对多个温度传感器进行控制和数据传输,并应用无线射频技术,将检测到的大棚温度数据传输至基站处理单元,实现对大棚温度的远程监控.     

Trial balloons in the southern hemisphere

Superpressure GHOST balloons are being launched from Christchurch, New Zealand, to determine their life, stability, and clustering characteristics at several altitudes. Thtee separate balloons have flown for more than 6 months at 200 millibars, proving capability of the long life that had been hoped for at such middle altitudes and providing preliminary trajectory data for the Southern Hemisphere. Icing problems at lower altitudes have not yet been solved. We expect future flight durations of several years at higher altitudes. If successful, the new balloons will be useful platforms for experimenters concerned with study of large-scale and long-term effects in the stratosphere.     

远洋渔业船载加工装备与技术研究进展

远洋渔船是远洋渔业船载加工和贮运的主要载体。由于远洋渔业渔获物来源集中、容易腐败、捕获后需要尽快加工,而且加工、贮运场所空间有限的特点,远洋渔业船载加工装备与技术已成为影响远洋渔业产业的"瓶颈"之一。通过广泛查阅国内外相关资料,综述了远洋渔业船载加工装备与技术的发展历程及现状,比较了国内外远洋渔业船载加工装备与技术的优势和不足,分析并预测了我国远洋渔业船载加工装备与技术的发展趋势,得出我国远洋渔业船载加工装备与技术将朝着装备标准化、技术先进化和功能综合化的方向发展。通过突破核心部件和关键技术,为发展节能环保、智能高效、综合利用的远洋渔业船载加工装备与技术提供保证,推动我国远洋渔业发展。     

基于GSM短信平台的灌溉自动控制器的开发

开发一种适合我国实际的基于GSM短信平台智能灌溉控制器，该控制器通过短信可以接收PC上位机或一般手机下传的控制命令，并通过无线射频通信控制灌溉阀门。控制器可以依据采集的环境参数或预先制定的程序进行灌溉，并具备数据查询功能。该仪器设计合理、命令简单、价格低廉，已经在北京某郊县和新疆某农场安装，运行效果满足实际要求。     

Overview of VEGA Venus Balloon in Situ Meteorological Measurements

The VEGA balloons made in situ measurements of pressure, temperature, vertical wind velocity, ambient light, frequency of lightning, and cloud particle backscatter. Both balloons encountered highly variable atmospheric conditions, with periods of intense vertical winds occurring sporadically throughout their flights. Downward winds as large as 3.5 meters per second occasionally forced the balloons to descend as much as 2.5 kilometers below their equilibrium float altitudes. Large variations, in pressure, temperature, ambient light level, and cloud particle backscatter (VEGA-1 only) correlated well during these excursions, indicating that these properties were strong functions of altitude in those parts of the middle cloud layer sampled by the balloons.     

A three-band hand-held radiometer for field use

A self-contained, hand-held radiometer designed for field use has been constructed and tested. The 4.5-kilogram device, consisting of a strap-supported electronics module and a hand-held probe containing three sensors, is powered by flashlight and transistor radio batteries, uses two silicon and one lead sulfide detector, has three liquid-crystal displays, features sample-and-hold radiometric sampling, and is spectrally configured to Landsat-D's thematic mapper bands TM3 (0.63 to 0.69 micrometer), TM4 (0.76 to 0.90 micrometer), and TM5 (1.55 to 1.75 micrometers). The device was designed to collect ground-truth data for the thematic mapper and to facilitate ground-based, remote-sensing studies of natural materials in situ. Prototype instruments were extensively tested under laboratory and field conditions, with satisfactory results.     

风廓线雷达在暴雨预报中的应用分析

与探空气球测风相比,风廓线雷达具有快速、连续、时空分辨率高、无需施放探空气球等优点。分析局地暴雨过程中的风廓线雷达资料的特点,提取降水信号,使风廓线雷达资料在短时强降水监测和预报中发挥作用具有十分重要的意义。华北区域的一次实例验证表明,风廓线雷达在暴雨预报中有很好的应用效果。     

Superpressure balloon flights in the tropical stratosphere

Seven balloons were launched successfully from Ascension Island in January 1969. The balloons, flown at altitudes of 20 and 24 kilometers, will make possible a detailed analysis of the stratospheric circulation near the equator and will hopefully lead to an understanding of the quasi-biennial stratospheric oscillation in the tropics.     

Thermal structure of the venus atmosphere in the middle cloud layer

Thermal structure measurements obtained by the two VEGA balloons show the Venus middle cloud layer to be generally adiabatic. Temperatures measured by the two balloons at locations roughly symmetric about the equator differed by about 6.5 kelvins at a given pressure. The VEGA-2 temperatures were about 2.5 kelvins cooler and those of VEGA-1 about 4 kelvins warmer than temperatures measured by the Pioneer Venus Large Probe at these levels. Data taken by the VEGA-2 lander as it passed through the middle cloud agreed with those of the VEGA-2 balloon. Study of individual frames of the balloon data suggests the presence of multiple discrete air masses that are internally adiabatic but lie on slightly different adiabats. These adiabats, for a given balloon, can differ in temperature by as much as 1 kelvin at a given pressure.     

Epidermal electronics

We report classes of electronic systems that achieve thicknesses, effective elastic moduli, bending stiffnesses, and areal mass densities matched to the epidermis. Unlike traditional wafer-based technologies, laminating such devices onto the skin leads to conformal contact and adequate adhesion based on van der Waals interactions alone, in a manner that is mechanically invisible to the user. We describe systems incorporating electrophysiological, temperature, and strain sensors, as well as transistors, light-emitting diodes, photodetectors, radio frequency inductors, capacitors, oscillators, and rectifying diodes. Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller.     

A Remote Irrigation Monitoring and Control System for continuous move systems. Part A: description and development

Continuous move irrigation systems have been modified since the 1990s to support variable rate irrigation. Most of these systems used PLC (Programmable Logic Controllers) technology that performed well for on-site control but were very expensive to add remote, real-time monitoring and control aspects that have been made possible by wireless sensor networks and the Internet. A new approach to the monitoring and control of continuous move irrigation systems is described. This system uses a Single Board Computer (SBC) using the Linux operating system to control solenoids connected to individual or groups of nozzles based on prescribed application maps. The main control box houses the SBC connected to a sensor network radio, a GPS (Global Positioning System) unit, and an Ethernet radio creating a wireless connection to a remote server. A C-software control program resides on the SBC to control the on/off time for each nozzle group using a “time on” application map developed remotely. The SBC also interfaces with the sensor network radio to record measurements from sensors on the irrigation system and in the field that monitor performance and soil and crop conditions. The SBC automatically populates a remote database on the server in real time and provides software applications to monitor and control the irrigation system through the Internet.     

Sensor data fusion to predict multiple soil properties

The accuracy of a single sensor is often low because all proximal soil sensors respond to more than one soil property of interest. Sensor data fusion can potentially overcome this inability of a single sensor and can best extract useful and complementary information from multiple sensors or sources. In this study, a data fusion was performed of a Vis?CNIR spectrometer and an EM38 sensor for multiple soil properties. Stepwise multiple linear regression (SMLR), partial least squares regression (PLSR) and principal components analysis combined with stepwise multiple linear regression (PCA?+?SMLR) methods were used in three different fields. Soil properties investigated for data fusion included soil texture (clay, silt and sand), EC, pH, total organic carbon (TOC), total nitrogen (TN) and carbon to nitrogen ratio (CN). It was found that soil property models based on fusion methods significantly improved the accuracy of predictions of soil properties measureable by both sensors, such as clay, silt, sand, EC and pH from those based on either of the individual sensors. The accuracy of predictions of TOC, TN and CN was also improved in some cases, but was not consistent in all fields. Among data fusion methods, PLSR outperformed both SMLR and PCA?+?SMLR methods because it proved to have a better ability to deal with the multi-collinearity among the predictor variables of both sensors. The best data fusion results were found in a clayey field and the worst in a sandy field. It is concluded that sensor data fusion can enhance the quality of soil sensing in precision agriculture once a proper set of sensors has been selected for fusion to estimate desired soil properties. More efficient statistical data analysis methods are needed to handle a large volume of data effectively from multiple sensors for sensor data fusion.     

Radio and plasma wave observations at Saturn from Cassini's approach and first orbit

We report data from the Cassini radio and plasma wave instrument during the approach and first orbit at Saturn. During the approach, radio emissions from Saturn showed that the radio rotation period is now 10 hours 45 minutes 45 +/- 36 seconds, about 6 minutes longer than measured by Voyager in 1980 to 1981. In addition, many intense impulsive radio signals were detected from Saturn lightning during the approach and first orbit. Some of these have been linked to storm systems observed by the Cassini imaging instrument. Within the magnetosphere, whistler-mode auroral hiss emissions were observed near the rings, suggesting that a strong electrodynamic interaction is occurring in or near the rings.     

Low altitude remote sensing technologies for crop stress monitoring: a case study on spatial and temporal monitoring of irrigated pinto bean

Site-specific crop management is a promising approach to maximize crop yield with optimal use of rapidly depleting natural resources. Availability of high resolution crop data at critical growth stages is a key for real-time data-driven decisions during the production season. The goal of this study was to evaluate the possibility of using small unmanned aerial system (UAS)-based remote sensing technologies to monitor the crop stress of irrigated pinto beans (Phaseolus vulgaris L.) with varied irrigation and tillage treatments. A small UAS with onboard multispectral and infrared thermal imaging sensors was used to collect data from bean field plots on three growth stages in 2015 and 2016, respectively. Indicators including green normalized vegetation index (GNDVI), canopy cover (CC, ratio of ground covered by crop canopy to the total plot area) and canopy temperature (CT, °C) of crops were extracted from imaging data and correlated with ground-reference crop yield and leaf area index (LAI) estimated with a handheld ceptometer. Results show that GNDVI, CC and CT were able to differentiate crops with full and deficit irrigation treatments at each of the three growth stages in both years. Developed indicators were strongly correlated with to the crop yield with Pearson correlation coefficients (r) of approximate 0.71 and 0.72 for GNDVI and CC, respectively, in the early growth stage (54 days after planting) in both years. Canopy temperature showed even stronger correlation (r > 0.8) with yield at early growth stage. Performance of small UAS-based imagery-based indicators in crop stress monitoring and crop yield estimation was better than or comparable to that of the ground-based LAI estimates, indicating the potential of such remote sensing tool in rapid crop stress monitoring and management.     

Time-critical social mobilization

The World Wide Web is commonly seen as a platform that can harness the collective abilities of large numbers of people to accomplish tasks with unprecedented speed, accuracy, and scale. To explore the Web's ability for social mobilization, the Defense Advanced Research Projects Agency (DARPA) held the DARPA Network Challenge, in which competing teams were asked to locate 10 red weather balloons placed at locations around the continental United States. Using a recursive incentive mechanism that both spread information about the task and incentivized individuals to act, our team was able to find all 10 balloons in less than 9 hours, thus winning the Challenge. We analyzed the theoretical and practical properties of this mechanism and compared it with other approaches.     

基于改进K-medoids算法的土壤墒情传感器布局优化

针对茶园土壤墒情传感器布局中传感器数量过多、数据冗余度过大的问题,采用改进的K-medoids方法,优化茶园土壤墒情传感器使用数量及部署位置。在保证茶园传感网络全覆盖的基础上,实时采集各传感节点数据;构造各传感器在不同天气条件下的时间序列数据,并运用三次样条插值法拟合成连续函数;应用谱排直法定义新的时间序列数据的距离函数替换K-medoids中的欧氏距离,将聚类中心作为最终的传感器布点;随机选取位置并采集土壤相对含水率以验证聚类中心作为传感器布点的代表性。采用改进前和改进后的K-medoids方法对2018-07—2018-08（试验Ⅰ）和2020-12（试验Ⅱ）采集的土壤墒情数据进行聚类。结果表明：1）改进的K-medoids将32个传感器减少到4个,改进前后簇中心墒情值与簇均值的相对偏差,试验Ⅰ由2.85%降到1.91%,试验Ⅱ由2.01%降到1.43%;2）改进K-medoids所得聚类中心相对含水率与试验区域平均值相近,相对偏差小于2%;3）以改进的K-medoids算法所得聚类中心作为起点的布点路径长度为82.4m,使用8个传感器,优于改进前的106.5m和10个传感器。基于...