Multivariate Calibration Domain Adaptation with Unlabeled Data

Multivariate calibration is about modeling the relationship between a substance\u27s chemical profile and its spectrum (here, near-infrared) in order to predict the concentration of new samples with known spectra. However, these new samples are often measured under different conditions than the primary conditions; different instruments, instrument drift, and temperature all affect the measurement conditions. Domain adaptation (DA) methods force the model to ignore these differences in order to generate an accurate model for the new domain (secondary conditions). There are two fundamental DA processes that individual methods can be classified under. One augments a few samples from the secondary domain with chemical reference values (labels) to the primary data and the other augments only secondary spectra (unlabeled data). In this work, we compare two existing labeled DA methods and two existing unlabeled DA methods to two novel labeled methods and a novel unlabeled approach. Since DA methods require selection of hyperparameters, a model selection framework based on model diversity and prediction similarity (MDPS) is applied to the DA methods. Regardless of the DA method, the MDPS process is shown to select models more accurate than the first quartile of all models generated by the DA process in three near-infrared datasets

Harnessing Model Diversity and Prediction Similarity for Selecting Multivariate Calibration Tuning Parameters

Spectral multivariate calibration offers a cost-effective mechanism to obtain sample analyte values of a substance (e.g. protein level). However, calibration requires varying one or more tuning parameters in order to identify the most accurate model. Model selection is particularly difficult for model updating where spectral and reference information in both the original (primary) conditions and new (secondary) conditions are combined in order to better predict new spectra. Secondary situations can be new instruments, temperatures, or other condition affecting the shape and magnitude of the spectra relative to the primary conditions and analyte values. This poster uses model diversity while maintaining similar analyte prediction values to choose a set of acceptable models. The model selection technique is tested across the calibration method partial least squares and four model updating methods: two require a small set of secondary samples with analyte values and two do not require the secondary analyte values (unlabeled data). Results are presented across a variety of datasets and conditions showing that the cosine of the angle between models in combination with model vector 2-norms and prediction differences are key to selecting models

Thermal status for different breeds of dairy cattle exposed to summer heat stress in a grazing environment [abstract]

Abstract only availableA study was conducted to investigate thermal balance of lactating dairy cattle managed in an intensive managed rotational grazing system. The farm was located at the University of Missouri Southwest Research Center in Vernon County, MO. Thirty six lactating dairy cows were blocked by parity, days in milk, milk production and breed. Cows were grouped by breed with 100% Holstein (H, n=8), 75%H:25% Jersey (J) (75H, n=5), 50%H:50%J (50H, n=8), 25%H:75%J (75J, n=7), and 100% J (J, n=8), and maintained on the same pastures from June 15 through August 1, 2006. Cows were rotated to paddocks to maintain ad libitum access to pasture. Ambient variables, including air temperature (Ta) and relative humidity, were measured continuously. Ranges of Ta and calculated THI were 12 to 38C and 55 to 87, respectively. Thermal balance was evaluated prior to morning (0500) and afternoon (1600) milkings by measuring rectal temperature (Tre) and respiration rate (RR) on 16 days throughout the study during periods of maximum and minimum heat stress. Breed groups had different body weights (p < 0.0001) ranging from 530 kg (H) to 378 (J). However, body weight was similar for 75J and 75H (460 kg versus 501 kg, respectively). Although body weights were different across breed, combined change in rectal temperature with Ta (r = 0.89) and THI (r = 0.92) was predictable (p < 0.0001). Change in Tre with increasing Ta and THI was slowest for J and 75J, and highest for H and 75H. Change in Tre was influenced more by breed more than body weight. Respiration rate was correlated with Ta (r = 0.88) and THI (r = 0.89) (p < 0.0001), with 75J being more responsive than 75H. These results suggest that breed selection can be used to improve thermal balance of cows in intensively managed rotational grazing systems.CAFNR On Campus Research Internshi

Nonlinear wakefields and electron injection in cluster plasma

Laser and beam driven wakefields promise orders of magnitude increases in electric field gradients for particle accelerators for future applications. Key areas to explore include the emittance properties of the generated beams and overcoming the dephasing limit in the plasma. In this paper, the first in-depth study of the self-injection mechanism into wakefield structures from non-homogeneous cluster plasmas is provided using high-resolution two dimensional particle-in-cell simulations. The clusters which are typical structures caused by ejection of gases from a high-pressure gas jet have a diameter much smaller than the laser wavelength. Conclusive evidence is provided for the underlying mechanism that leads to particle trapping, comparing uniform and cluster plasma cases. The accelerated electron beam properties are found to be tunable by changing the cluster parameters. The mechanism explains enhanced beam charge paired with large transverse momentum and energy which has implications for the betatron x-ray flux. Finally, the impact of clusters on the high-power laser propagation behavior is discussed

Methods for Extremely Sparse-Angle Proton Tomography

Proton radiography is a widely-fielded diagnostic used to measure magnetic structures in plasma. The deflection of protons with multi-MeV kinetic energy by the magnetic fields is used to infer their path-integrated field strength. Here, the use of tomographic methods is proposed for the first time to lift the degeneracy inherent in these path-integrated measurements, allowing full reconstruction of spatially resolved magnetic field structures in three dimensions. Two techniques are proposed which improve the performance of tomographic reconstruction algorithms in cases with severely limited numbers of available probe beams, as is the case in laser-plasma interaction experiments where the probes are created by short, high-power laser pulse irradiation of secondary foil targets. The methods are equally applicable to optical probes such as shadowgraphy and interferometry [M. Kasim et al. Phys. Rev. E 95, 023306 (2017)], thereby providing a disruptive new approach to three dimensional imaging across the physical sciences and engineering disciplines.Comment: 11 pages, 6 figures, companion article to arXiv:2103.1126

Assessing fishery and ecological consequences of alternate management options for multispecies fisheries

Demands for management advice on mixed and multispecies fisheries pose many challenges, further complicated by corresponding requests for advice on the environmental impacts of alternate management options. Here, we develop, and apply to North Sea fisheries, a method for collectively assessing the effects of, and interplay between, technical interactions, multispecies interactions, and the environmental effects of fishing. Ecological interactions involving 21 species are characterized with an ensemble of 188 plausible parameterizations of size-based multispecies models, and four fleets (beam trawl, otter trawl, industrial, and pelagic) characterized with catch composition data. We use the method to evaluate biomass and economic yields, alongside the risk of stock depletion and changes in the value of community indicators, for 10 000 alternate fishing scenarios (combinations of rates of fishing mortality F and fleet configuration) and present the risk vs. reward trade-offs. Technical and multispecies interactions linked to the beam and otter trawl fleets were predicted to have the strongest effects on fisheries yield and value, risk of stock collapse and fish community indicators. Increasing beam trawl effort led to greater increases in beam trawl yield when otter trawl effort was low. If otter trawl effort was high, increases in beam trawl effort led to reduced overall yield. Given the high value of demersal species, permutations of fleet effort leading to high total yield (generated primarily by pelagic species) were not the same as permutations leading to high catch values. A transition from F for 1990 to 2010 to FMSY, but without changes in fleet configuration, reduced risk of stock collapse without affecting long-term weight or value of yield. Our approach directly addresses the need for assessment methods that treat mixed and multispecies issues collectively, address uncertainty, and take account of trade-offs between weight and value of yield, state of stocks and state of the environment

Advantages to a diverging Raman amplifier

The plasma Raman instability can efficiently compress a nanosecond long high-power laser pulse to sub-picosecond duration. Although, many authors envisaged a converging beam geometry for Raman amplification, here we propose the exact opposite geometry; the amplification should start at the intense focus of the seed. We generalise the coupled laser envelope equations to include this non-collimated case. The new geometry completely eradicates the usual trailing secondary peaks of the output pulse, which typically lower the efficiency by half. It also reduces, by orders of magnitude, the initial seed pulse energy required for efficient operation. As in the collimated case, the evolution is self similar, although the temporal pulse envelope is different. A two-dimensional particle-in-cell simulation demonstrates efficient amplification of a diverging seed with only 0.3 mJ energy. The pulse has no secondary peaks and almost constant intensity as it amplifies and diverges