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| 1 | Development and prospect of unmanned aerial vehicle technologies for agricultural production management显示文摘Unmanned aerial vehicles have been developed and applied to support agricultural production management.Compared with piloted aircraft,an Unmanned Aerial Vehicle(UAV)can focus on small crop fields at lower flight altitudes than regular aircraft to perform site-specific farm management with higher precision.They can also“fill in the gap”in locations where fixed winged or rotary winged aircraft are not readily available.In agriculture,UAVs have primarily been developed and used for remote sensing and application of crop production and protection materials.Application of fertilizers and chemicals is frequently needed at specific times and locations for site-specific management.Routine monitoring of crop plant health is often required at very high resolution for accurate site-specific management as well.This paper presents an overview of research involving the development of UAV technology for agricultural production management.Technologies,systems and methods are examined and studied.The limitations of current UAVs for agricultural production management are discussed,as well as future needs and suggestions for development and application of the UAV technologies in agricultural production management. | Yanbo Huang Steven J.Thomson W.Clint Hoffmann Yubin Lan Bradley K.Fritz | 2013 | International Journal of Agricultural and Biological Engineering2013，6，3： | 22 |
| 2 | Characterization of spray deposition and drift from a low drift nozzle for aerial application at different application altitudes显示文摘A complex interaction of controllable and uncontrollable factors is involved in aerial application of crop production and protection materials.Although it is difficult to completely characterize spray deposition and drift,these important factors can be estimated with appropriate sampling protocol and analysis.Application height is an important variable influencing off-target spray drift,but this variable has not been easily measured or logged.A custom-configured aircraft-mounted laser with logging capabilities makes this possible.This study was designed to investigate droplet size and deposition characteristics of a low drift CP flat-fan nozzle at application altitudes 3.7 m,4.9 m,and 6.1 m.In the study,CP flat-fan nozzles were set to a downward angle of 30 degrees applying a mixture of water,Syl-Tac®adjuvant,and Rubidium Chloride(RbCl)tracer at a 28.5 L/ha application rate.Spray droplets were collected using water sensitive paper(WSP)cards placed in the spray swath.Mylar sheets were also placed in the swath and downwind for drift sampling.Statistical analysis indicated that median droplet diameter as determined by WSP in the spray swath was not significantly influenced by spray application height.Similarly,statistical analysis also indicated that concentration of RbCl tracer from Mylar samplers in the spray swath was not significantly influenced by application height.Application height had a significant effect on spray deposition from drift samplers,along with wind direction and relative humidity.Final results for drift samplers may have been influenced by shifts in wind direction that altered the relationship between orientation of samplers and wind. | Yanbo Huang Steven J.Thomson | 2011 | International Journal of Agricultural and Biological Engineering2011，4，4： | 16 |
| 3 | Multispectral imaging systems for airborne remote sensing to support agricultural production management显示文摘This study investigated three different types of multispectral imaging systems for airborne remote sensing to support management in agricultural application and production.The three systems have been used in agricultural studies.They range from low-cost to relatively high-cost,manually operated to automated,multispectral composite imaging with a single camera and integrated imaging with custom-mounting of separate cameras.Practical issues regarding use of the imaging systems were described and discussed.The low-cost system,due to band saturation,slow imaging speed and poor image quality,is more preferable to slower moving platforms that can fly close to the ground,such as unmanned autonomous helicopters,but not recommended for low or high altitude aerial remote sensing on fixed-wing aircraft.With the restriction on payload unmanned autonomous helicopters are not recommended for high-cost systems because they are typically heavy and difficult to mount.The system with intermediate cost works well for low altitude aerial remote sensing on fixed-wing aircraft with field shapefile-based global positioning triggering.This system also works well for high altitude aerial remote sensing on fixed-wing aircraft with global positioning triggering or manually operated.The custom-built system is recommended for high altitude aerial remote sensing on fixed-wing aircraft with waypoint global positioning triggering or manually operated. | Yanbo Huang Steven J.Thomson Yubin Lan Stephan J.Maas | 2010 | International Journal of Agricultural and Biological Engineering2010，3，1： | 12 |
| 4 | All-silicon carrier accumulation modulator based on a lateral metal-oxide-semiconductor capacitor显示文摘In silicon photonics, the carrier depletion scheme has been the most commonly used mechanism for demonstrating high-speed electro-optic modulation. However, in terms of phase modulation efficiency, carrieraccumulation-based devices potentially offer almost an order of magnitude improvement over those based on carrier depletion. Previously reported accumulation modulator designs only considered vertical metal-oxidesemiconductor(MOS) capacitors, which imposes serious restrictions on the design flexibility and integratability with other photonic components. In this work, for the first time to our knowledge, we report experimental demonstration of an all-silicon accumulation phase modulator based on a lateral MOS capacitor. Using a Mach–Zehnder interferometer modulator with a 500-μm-long phase shifter, we demonstrate high-speed modulation up to 25 Gbit∕s with a modulation efficiency(V_πL_π) of 1.53 V·cm. | KAPIL DEBNATH DAVID J.THOMSON WEIWEI ZHANG ALI Z.KHOKHAR CALLUM LITTLEJOHNS JAMES BYERS LORENZO MASTRONARDI MUHAMMAD K.HUSAIN KOUTA IBUKURO FREOERIC Y.GARDES GRAHAM T,REED SHINICHI SAITO | 2018 | Photonics Research2018，6，5： | 6 |
| 5 | Development and evaluation of low-altitude remote sensing systems for crop production management显示文摘Precision agriculture accounts for within-field variability for targeted treatment rather than uniform treatment of an entire field.It is built on agricultural mechanization and state-of-the-art technologies of geographical information systems(GIS),global positioning systems(GPS)and remote sensing,and is used to monitor soil,crop growth,weed infestation,insects,diseases,and water status in farm fields to provide data and information to guide agricultural management practices.Precision agriculture began with mapping of crop fields at different scales to support agricultural planning and decision making.With the development of variable-rate technology,precision agriculture focuses more on tactical actions in controlling variable-rate seeding,fertilizer and pesticide application,and irrigation in real-time or within the crop season instead of mapping a field in one crop season to make decisions for the next crop season.With the development of aerial variable-rate systems,low-altitude airborne systems can provide high-resolution data for prescription variable-rate operations.Airborne systems for multispectral imaging using a number of imaging sensors(cameras)were developed.Unmanned aerial vehicles(UAVs)provide a unique platform for remote sensing of crop fields at slow speeds and low-altitudes,and they are efficient and more flexible than manned agricultural airplanes,which often cannot provide images at both low altitude and low speed for capture of high-quality images.UAVs are also more universal in their applicability than agricultural aircraft since the latter are used only in specific regions.This study presents the low-altitude remote sensing systems developed for detection of crop stress caused by multiple factors.UAVs,as a special platform,were discussed for crop sensing based on the researchers'studies. | Yanbo Huang Steven J.Thomson Howard J.Brand Krishna N.Reddy | 2016 | International Journal of Agricultural and Biological Engineering2016，9，4： | 5 |
| 6 | Portable device to assess dynamic accuracy of global positioning system(GPS)receivers used in agricultural aircraft显示文摘A device was designed to test the dynamic accuracy of Global Positioning System(GPS)receivers used in agricultural aircraft and other aerial vehicles.The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors.A photo detector points downward from the aircraft to detect the light beam,and photo detection circuitry triggers an event in the guidance system data file at the aircraft’s location corresponding to the precisely georeferenced position on the ground.Construction details are presented on the mirror-based light reflection system and photo-electronic circuitry designed to trigger an event in the guidance system’s log file.An example application evaluated the horizontal accuracy of a stand-alone GPS receiver by matching dynamic data with data from the aircraft’s guidance system.Results indicated a 2.16 s lead in position registered by the stand-alone receiver over that registered by the aircraft’s guidance system GPS receiver,which had been previously evaluated to be within 0.13 s of Real-Time Kinematic(RTK)-referenced time and position. | Steven J.Thomson Yanbo Huang Lowrey A.Smith | 2014 | International Journal of Agricultural and Biological Engineering2014，7，2： | 4 |
| 7 | Ground-based hyperspectral remote sensing for weed management in crop production显示文摘Agricultural remote sensing has been developed and applied in monitoring soil,crop growth,weed infestation,insects,diseases and water status in farm fields to provide data and information to guide agricultural management practices.Precision agriculture has been implemented through prescription mapping of crop fields at different scales with the data remotely sensed from space-borne,airborne and ground-based platforms.Ground-based remote sensing techniques offer portability,flexibility and controllability in applications for precision agriculture.In weed management,crop injury from off-target herbicide spray drift and herbicide resistance in weeds are two important issues.For precision weed management,ground-based hyperspectral remote sensing techniques were developed for detection of crop injury from dicamba and differentiation between glyphosate resistant and sensitive weeds.This research presents the techniques for ground-based hyperspectral remote sensing for these two applications.Results illustrate the advantages of ground-based hyperspectral remote sensing for precision weed management. | Yanbo Huang Matthew A.Lee Steven J.Thomson Krishna N.Reddy | 2016 | International Journal of Agricultural and Biological Engineering2016，9，2： | 3 |
| 8 | Estimation of cotton yield with varied irrigation and nitrogen treatments using aerial multispectral imagery显示文摘Cotton yield varies spatially within a field.The variability can be caused by various production inputs such as soil properties,water management,and fertilizer application.Airborne multispectral imaging is capable of providing data and information to study effects of the inputs on yield qualitatively and quantitatively in a timely and cost-effective fashion.A 10-ha cotton field with irrigation and non-irrigation 2×2 blocks was used in this study.Six nitrogen application treatments were randomized with two replications within each block.As plant canopy was closed,airborne multispectral images of the field were acquired using a 3-CCD MS4100 camera.The images were processed to generate various vegetation indices.The vegetation indices were evaluated for the best performance to characterize yield.The effect of irrigation on vegetation indices was significant.Models for yield estimation were developed and verified by comparing the estimated and actual yields.Results indicated that ratio of vegetation index(RVI)had a close relationship with yield(R^(2)=0.47).Better yield estimation could be obtained using a model with RVI and soil electrical conductivity(EC)measurements of the field as explanatory variables(R^(2)=0.53).This research demonstrates the capability of aerial multispectral remote sensing in estimating cotton yield variation and considering soil properties and nitrogen. | Yanbo Huang Ruixiu Sui Steven J.Thomson Daniel K.Fisher | 2013 | International Journal of Agricultural and Biological Engineering2013，6，2： | 3 |
| 9 | Characterizing downwind drift deposition of aerially applied glyphosate using RbCl as tracer显示文摘Rubidium chloride(RbCl)was used as a tracer tank-mixed with active ingredients to profile downwind deposition of aerially applied crop protection and production materials to characterize off-target drift,which helps improve spray efficiency and reduce environmental contamination.Mylar sheets were placed on a holder in the field at each sampling station to collect sprayed solution.RbCl tracer was used to assess downwind drift of nozzles mounted on the booms installed and controlled on both sides of an agricultural airplane.The experiment was conducted on a field covered by Bermuda grass(Cynodon dactylon).During the experiment,the airplane was planned to fly three passes with three replications at each of three different altitudes,3.7 m,4.9 m,and 6.1 m for total of 27 flight runs.The results indicated that sampling station location had a significant effect on RbCl concentration.However,application release altitude was not significant to the change of RbCl.Another practical application in the same aerial application system was used to assess crop injury from the off-target drift of aerially applied glyphosate.RbCl concentrations measured from Mylar sheets were correlated with visual injury,plant height,shoot dry weight,leaf chlorophyll content,and shikimate,which were measured from the leaves and plant samples collected.Overall,RbCl is an effective tracer for monitoring spray applications from agricultural aircraft and unmanned aerial vehicles to intensify agriculture output and minimize environmental impact. | Yanbo Huang Claudiane M.Ouellet-Plamondon Steven J.Thomson Krishna N.Reddy | 2017 | International Journal of Agricultural and Biological Engineering2017，10，3： | 2 |
| 10 | Post-fabrication phase trimming of Mach–Zehnder interferometers by laser annealing of germanium implanted waveguides显示文摘We demonstrate a novel high-accuracy post-fabrication trimming technique to fine-tune the phase of integrated Mach–Zehnder interferometers, enabling permanent correction of typical fabrication-based phase errors. The effective index change of the optical mode is 0.19 in our measurement, which is approximately an order of magnitude improvement compared to previous work with similar excess optical loss. Our measurement results suggest that a phase accuracy of 0.078 rad was achievable with active feedback control. | XIA CHEN MILAN M.MILOSEVIC DAVID J.THOMSON ALI Z.KHOKHAR YOHANN FRANZ ANTOINE F.J.RUNGE SAKELLARIS MAILIS ANNA C.PEACOCK GRAHAM T.REED | 2017 | Photonics Research2017，5，6： | 1 |
| 11 | Expression of Bcl‐x, Bcl‐2, Bax, and Bak in endarterectomy and atherectomy specimens显示文摘 | A.Saxena J. D.McMeekin D. J.Thomson | 2002 | J Pathol2002，，3： | 1 |
| 12 | Direct ex vivo comparison of the breadth and specificity of the T?cells in the liver and peripheral blood of patients with chronic HCV infection显示文摘 | Anna M.Grabowska FranziskaLechner PaulKlenerman Paddy J.Tighe StephenRyder Jonathan K.Ball Brian J.Thomson William L.Irving R. AdrianRobins | 2001 | Eur J Immunol2001，，8： | 1 |
| 13 | Is there a latitudinal gradient in the proportion of species with spinescence?显示文摘Aims We aimed to test the hypothesis that plants that grow at lower lati-tudes will be better structurally defended than plants from higher latitudes.Methods We collated binary spinescence data for 5145 species across Australia and New Zealand.Our dataset spanned 35°of latitude,and included over 1 million observations,making it the larg-est empirical study ever conducted for a single physical defence trait.A weighted logistic regression was applied first within Australia and New Zealand separately,and then across the com-bined dataset.Important Findings There was no significant latitudinal gradient in the proportion of spe-cies with spinescence in Australia or New Zealand,or in the overall dataset.That is,plant species are no more likely to be defended by spines at low latitudes than at high latitudes.This finding is counter to the idea that plant defences increase with latitude due to increased selective pressure from higher levels of herbivory.We suggest that future studies should investigate the relationship between herbivory and defence directly,without using latitude as a proxy. | Marianne L.Tindall Fiona J.Thomson Shawn W.Laffan Angela T.Moles | 2017 | Journal of Plant Ecology2017，10，2： | 1 |
| 14 | Apodized silicon photonic grating couplers for mode-order conversion显示文摘An out-of-plane silicon grating coupler capable of mode-order conversion at the chip–fiber interface is designed and fabricated. Optimization of the structure is performed through finite-difference time-domain simulations,and the final device is characterized through far-field profile and transmission measurements. A coupling loss of 3.1 dB to a commercial two-mode fiber is measured for a single TE0→ LP11 mode conversion grating, which includes a conversion penalty of 1.3 dB. Far-field patterns of the excited LP11 mode profile are also reported. | IOSIF DEMIRTZIOGLOU COSIMO LACAVA ABDUL SHAKOOR ALI KHOKHAR YONGMIN JUNG DAVID J.THOMSON PERIKLIS PETROPOULOS | 2019 | Photonics Research2019，7，9： | 1 |
| 15 | Atypical group 1 neuraminidase pH1N1-N1 bound to a group 1 inhibitor显示文摘 | Ying Wu Christopher J. Vavricka Yan Wu Qina Li Santosh Rudrawar Robin J.Thomson Mark yon Itzstein George F. Gao Jianxun Qi | 2015 | Protein & Cell2015，6，10： | 0 |
| 16 | Apodized silicon photonic grating couplers for mode-order conversion: publisher's note显示文摘 | Iosif Demirtzioglou Cosimo Lacava Abdul Shakoor Ali Khokhar Yongmin Jung David J.Thomson Periklis Petropoulos | 2019 | Photonics Research2019，7，11： | 0 |
| 17 | High-speed silicon photonic electro-optic Kerr modulation显示文摘Silicon-based electro-optic modulators contribute to easing the integration of high-speed and low-power consumption circuits for classical optical communications and data computations.Beyond the plasma dispersion modulation,an alternative solution in silicon is to exploit the DC Kerr effect,which generates an equivalent linear electro-optical effect enabled by applying a large DC electric field.Although some theoretical and experimental studies have shown its existence in silicon,limited contributions relative to plasma dispersion have been achieved in high-speed modulation so far.This paper presents high-speed optical modulation based on the DC Kerr effect in silicon PIN waveguides.The contributions of both plasma dispersion and Kerr effects have been analyzed in different waveguide configurations,and we demonstrated that the Kerr induced modulation is dominant when a high external DC electric field is applied in PIN waveguides.High-speed optical modulation response is analyzed,and eye diagrams up to 80 Gbit/s in NRZ format are obtained under a d.c.voltage of 30 V.This work paves the way to exploit the Kerr effect to generate high-speed Pockels-like optical modulation. | JONATHAN PELTIER WEIWEI ZHANG LEOPOLD VIROT CHRISTIAN LAFFORGUE LUCAS DENIEL DELPHINE MARRIS-MORINI GUY AUBIN FARAH AMAR DENH TRAN XINGZHAO YAN C1ALLUM G.LITTLEJOHNS CARLOS ALONSO-RAMOS KE LI DAVID J.THOMSON G1RAHAM REED LAURENT VIVIEN | 2024 | Photonics Research2024，12，1： | 0 |
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