Inside Out: Transforming Images of Lab-Grown Plants for Machine Learning Applications in Agriculture

Machine learning tasks often require a significant amount of training data for the resultant network to perform suitably for a given problem in any domain. In agriculture, dataset sizes are further limited by phenotypical differences between two plants of the same genotype, often as a result of differing growing conditions. Synthetically-augmented datasets have shown promise in improving existing models when real data is not available. In this paper, we employ a contrastive unpaired translation (CUT) generative adversarial network (GAN) and simple image processing techniques to translate indoor plant images to appear as field images. While we train our network to translate an image containing only a single plant, we show that our method is easily extendable to produce multiple-plant field images. Furthermore, we use our synthetic multi-plant images to train several YoloV5 nano object detection models to perform the task of plant detection and measure the accuracy of the model on real field data images. Including training data generated by the CUT-GAN leads to better plant detection performance compared to a network trained solely on real data.Comment: 35 pages, 23 figure

Full-scale validation of bio-recycled asphalt mixtures for road pavements

Recycling of asphalt has become a well-established practice in many countries, however the road pavement industry remains a bulk consumer of extracted raw materials. Novel solutions that find root in circular economy concepts and life‐cycle approaches are needed in order to enable optimisation of infrastructure resource efficiency, starting from the design stage and spanning the whole value chain in the construction sector. Itis within this framework that the present study presents a full-scale validation of asphalt mixtures specifically designed to ensure durability of flexible road pavements and at the same time enabling the reuse of reclaimed asphalt pavement (RAP) through the incorporation of bio-materials as recycling agent. These bio-recycled asphalt mixtures have been first designed in laboratory and subsequently validated in a real scale experiment conducted at the accelerated pavement testing facilities at IFSTTAR. Four pavement sections were evaluated: three test sections with innovative bio-materials, and a reference section with a conventional, high modulus asphalt mix (EME2). Two tests were realized: a rutting test and a fatigue test and for each of them the evolution of bio-recycled asphalt mixtures properties as well as the pavement deteriorations were recorded and studied. Evolution of the bio-asphalt mixtures was monitored for a 5 months period after paving by a bespoke nondestructive micro-coring, extracting and recovering methodology developed at the Western Research Institute (WRI). The structural health of the pavement sections was monitored through periodic falling weight deflectometer (FWD) as well as with strain gages and temperature sensors. As a result the three tailored bio-asphalt mixtures performed similarly or better than the control mixture, both in terms of property evolutions and durability

Performance of a sustainable asphalt mix incorporating high RAP content and novel bio-derived binder

The recent drive to find ways to increase sustainability and decrease costs in asphalt paving has led researchers to find innovative ways to incorporate more recycled materials and bio-derived binders into mixes with varying success. A new novel bio-derived binder made from refined pine chemistry stabilised with a polymer can increase the sustainability of asphalt mixes while maintaining pavement performance. Laboratory performance testing was conducted on asphalt mixes containing 50% Reclaimed Asphalt Pavement (RAP) by mix weight and the novel bio-derived binder. Results show that the bio-derived binder outperforms the conventional 50/70 pen grade binder mixes with respect to resistance to thermal cracking and adequately passes all requirements for pavements with 20-year design loadings of less than 30 million ESALs. This research shows that asphalt mixes containing 50% RAP and a bio-derived binder can be designed to pass performance criteria at low, intermediate, and high temperatures without the need of neat bitumen

Design and Realisation of DHBTs for High Frequency and High Power Applications

No abstract available

Intrinsic Delay Times in Single and Double HBTs Directly Extracted from Measured S-Parameter Data

A new method is presented to evaluate the base and collector transit times, tB and 'te, in Heterojunction Bipolar Transistors (HBTs) from the phase and magnitude of the common-base current gain, a( co), directly extracted from measured Sparameter data. The method is applied to InGaP/GaAs single and double HBTs. A smaller cut-off frequency in the latter device is attributed to 'tB and te due to the trapping of electrons in the conduction band triangular barrier existing ill the basecollector (B-C) heterojunction and smaller saturation velocity of electrons in InGaP as compared to GaAs, respectively. Finally, a new B-C design of InGaP/GaAs DHBTs is proposed to partially compensate the transit time effects

Loss of consumers constrains phenotypic evolution in the resulting food web

The loss of biodiversity is altering the structure of ecological networks; however, we are currently in a poor position to predict how these altered communities will affect the evolution of remaining populations. Theory on fitness landscapes provides a framework for predicting how selection alters the evolutionary trajectory and adaptive potential of populations, but often treats the network of interacting populations as a “black box.” Here, we integrate ecological networks and fitness landscapes to examine how changes in food‐web structure shape phenotypic evolution. We conducted a field experiment that removed a guild of larval parasitoids that imposed direct and indirect selection pressures on an insect herbivore. We then measured herbivore survival as a function of three key phenotypic traits to estimate directional, quadratic, and correlational selection gradients in each treatment. We used these selection gradients to characterize the slope and curvature of the fitness landscape to understand the direct and indirect effects of consumer loss on phenotypic evolution. We found that the number of traits under directional selection increased with the removal of larval parasitoids, indicating evolution was more constrained toward a specific combination of traits. Similarly, we found that the removal of larval parasitoids altered the curvature of the fitness landscape in such a way that tended to decrease the evolvability of the traits we measured in the next generation. Our results suggest that the loss of trophic interactions can impose greater constraints on phenotypic evolution. This indicates that the simplification of ecological communities may constrain the adaptive potential of remaining populations to future environmental change

Investigation of the Relation Between Primary Topographic Variables with Presence, Frequency and Quantitative Characteristics of Plant Species and Vegetation Types (Case Study: Baghe- Shadi Forest, Harat, Yazd)

To investigate the relationship between slope, aspect and elevation and quantitative characteristics of plant species, totally 125 sampling plots were selected in a block systematic design. In each sampling, plot presence, number, height, diameter at breast height (for trees) or root collar (for shrubs) and crown diameters were measured and recorded. Also, we recorded vegetation type according to the portion of species in the plot. Correlation analysis was conducted according to the scale of variables using Pierson, Spearman, Phi and Cramer and Eta coefficients. Results found that elevation is the most important factor affecting presence and density and also type in the study area. Altogether, Atlas Pistach (P. atlantica F. & M) and Wild Almond (A. scoparia Spach. ) in low elevations and Maple (A. cinerascens L.), Marsh-arrow-grass (A. lycioedes Spach.) and mountain almond (A. elaefnifolia Spach.) in higher elevations had better conditions. Slope had a negative correlation with presence of Wild Almond and Send Cherry (Ephedra spp), and positive correlation with the presence of other species. Also, Wild Pistach trees present in southern aspects showed more basal area and volume in these aspects. Results of this research can be used in the detection of suitable points for development of plant species. Regression analysis showed that frequency of almond and Send Cherry and average height of almond and wild Pistach were predictable according to elevation and slope. Of course, coefficient of determination was low in all cases

Stepping toward standard methods of small-signal parameter extraction for HBT's

An improved HBT small-signal parameter extraction procedure is presented in which all the equivalent circuit elements are extracted analytically without reference to numerical optimization. Approximations required for simplified formulae used in the extraction routine are revised, and it is shown that the present method has a wide range of applicability, which makes it appropriate for GaAs- and InP-based single and double HBT’s. Additionally, a new method is developed to extract the total delay time of HBT’s at low frequencies, without the need to measure 21 at very high frequencies and/or extrapolate it with 20 dB/dec roll-off. The existing methods of finding the forward transit time are also modified to improve the accuracy of this parameter and its components. The present technique of parameter extraction and delay time analysis is applied to an InGaP/GaAs DHBT and it is shown that: 1) variations of all the extracted parameters are physically justifiable; 2) the agreement between the measured and simulated - and -parameters in the entire range of frequency is excellent; and 3) an optimization step following the analytical extraction procedure is not necessary. Therefore, we believe that the present technique can be used as a standard extraction routine applicable to various types

Study of Forward and Reverse Gummel Plots for the Design of Collector-Up HBTs

No abstract available