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Yu X.,Northwest Agriculture and Forestry University | Yu X.,Research Institute of Water saving Agriculture of Arid Regions of China | Wu P.,Northwest Agriculture and Forestry University | Wu P.,CAS Institute of Soil and Water Conservation | And 3 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

The wireless sensor network technology was researched. Some wireless underground sensor network nodes and a sink node based on embedded technology and RF technology were designed innovatively. WUSN node consists of sensor, the processor, wireless communication module and power module, including processor using MSP430 microcontroller, RF modules adopting nRF905 communication module which having 433/868/915 MHz 3 ISM channel, the sink node is made up RF transceiver module, the core control circuit, information processing, data storage, LCD module and power supply. The nodes which acquired soil parameters information were regularly distributed in the monitoring area. The sink node collected the information of nodes that were sent in way of a single jumping or multiple hops and implemented fusion, analysis, processing, storage and display of information. For 50% sands, 35%silt, and 15% clay, a bulk density of 1.5 g/cm3 and a specific density of 2.6 / cm3, test for different soil moisture (5%, 10%, 15%, 20% and 25%) in three different frequencies, result shows that radio signal path loss is the minimum in the low frequency and low moisture. Moreover, the changes of node deployed depth (0.2 m, 0.4 m, 0.6 m,0.8 m, 1m, 1.2 m, 1.4 m, 1.6m, 1.8 m and 2m) affected signal attenuation under 433MHz, it is concluded that the best WUSN node buried depth for effective transmission. © 2011 Springer-Verlag. Source


Yu X.,Northwest University, China | Wu P.,Northwest Agriculture and Forestry University | Wu P.,CAS Institute of Soil and Water Conservation | Wu P.,Research Institute of Water saving Agriculture of Arid Regions of China | And 5 more authors.
Journal of Computers (Finland) | Year: 2013

Wireless underground sensor networks (WUSN) are a natural extension of the wireless sensor networks (WSN) phenomenon to the underground environment. In this work, experimental measurements are presented at the frequency of 433 MHz, which show a good agreement with the theoretical studies. Experiments are run to examine the received signal strength and the packet error rate for aboveground-to-underground and underground-to-aboveground communication links. The results reveal that the effects of burial depth, inter-node distance and volumetric water content of the soil on the signal strength and packet error rate. The tests show that the communication range decreased when the soil moisture increased. © 2013 ACADEMY PUBLISHER. Source


Zhang Z.,Northwest Agriculture and Forestry University | Zhang Z.,Research Institute of Water saving Agriculture of Arid Regions of China | Han W.,Northwest Agriculture and Forestry University | Han W.,Research Institute of Water saving Agriculture of Arid Regions of China | Chen J.,Northwest Agriculture and Forestry University
Applied Mechanics and Materials | Year: 2013

At present, in view of the status that the common DC power supply output voltage is fixed single, non-adjustable and practicality poor, this paper introduces a kind of numerical control power system that has many source output by using switch power supply circuit technology. The output voltage of the power based on single chip technology is numerical control adjustment. The major component of the power is voltage regulator circuit, input over-voltage protection circuit, output over-voltage protection circuit, DC/AC conversion circuit, filter circuit and full-bridge circuit. The power can offer a variety of different stable voltage output values and has display function. Through the PROTEUS software simulation and circuit testing, output effect of the power is good, practicability is great, and can be used as a variety of portable electrical universal power supply. © (2013) Trans Tech Publications, Switzerland. Source


Yu X.,Northwest Agriculture and Forestry University | Wu P.,Northwest Agriculture and Forestry University | Wu P.,CAS Institute of Soil and Water Conservation | Wu P.,Research Institute of Water saving Agriculture of Arid Regions of China | And 6 more authors.
Journal of Computational Information Systems | Year: 2012

Wireless sensor networks (WSN) have gained world-wide attention in recent years, which has important applications such as remote environmental monitoring. The goal of our survey is to present the applications research of the wireless terrestrial sensor networks and the wireless underground sensor networks (WUSN). The tests show the potential feasibility of the WUSN with the use of powerful RF transceivers at 433MHz frequency. Finally, we conclude that the effects of burial depth, inter-node distance and volumetric water content of the soil on the signal strength and packet error rate. © 2012 Binary Information Press. Source


Yu X.,Northwest Agriculture and Forestry University | Wu P.,Northwest Agriculture and Forestry University | Wu P.,CAS Institute of Soil and Water Conservation | Wu P.,Research Institute of Water saving Agriculture of Arid Regions of China | And 6 more authors.
Progress In Electromagnetics Research M | Year: 2013

Wireless underground sensor networks (WUSN) consist of wireless devices that operate below the ground surface. These devices are buried completely under dense soil, thus electromagnetic wave transmits only through soil medium. However, the high attenuation that caused by soil is the main challenge for the electromagnetic wave transmission for WUSN. In this study, architecture of wireless underground sensor network communication was established. The experimental measurements were conducted using WUSN sensor nodes at three different carrier frequencies, respectively. Received signal strength and packet error rate were examined for communication links between the sensor nodes. The test results showed that carrier frequency was one of the main factors that affected electromagnetic wave propagation in the soil medium. It was concluded that the burial depth of the sensor nodes, horizontal inter-node distance, and soil volumetric water content have significant impacts on the signal strength and packet error rate during the electromagnetic wave propagation within a WUSN. Source

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