Realizing packaged state-of-the-art performance of monolithic microwave integrated circuits (MMICs) operating at millimeter wavelengths presents significant challenges in terms of electrical interface circuitry and physical construction. For instance, even with the aid of modern electromagnetic simulation tools, modeling the interaction between the MMIC and its package embedding circuit can lack the necessary precision to achieve optimum device performance. Physical implementation also introduces inaccuracies and requires iterative interface component substitution that can produce variable results, is invasive and risks damaging the MMIC. This paper describes a novel method for in situ optimization of packaged millimeter-wave devices using a pulsed ultraviolet laser to remove pre-selected areas of interface circuit metallization. The method was successfully demonstrated through the optimization of a 183 GHz low noise amplifier destined for use on the MetOp-SG meteorological satellite series. An improvement in amplifier output return loss from an average of 12.9 dB to 22.7 dB was achieved across an operational frequency range of 175–191 GHz and the improved circuit reproduced. We believe that our in situ tuning technique can be applied more widely to planar millimeter-wave interface circuits that are critical in achieving optimum device performance.

Crop insurance is the cornerstone program of domestic farm policy in most developed countries. Although most countries’ rating methodology corrects for time-varying movements in the first two moments, it is unclear whether using the entire yield series remains appropriate.  We use distributional tests and an out-of-sample retain-cede rating game to answer whether governments/insurers should historically trim yields in estimating their premium rates. Despite small sample sizes and the need to estimate tail probabilities, the historical data appear to be sufficiently different such that trimming is justified.

Most farmers now rely on herbicides and, to a lesser extent, cultivation to control weeds in Glycine max in the Midwest. However, the general public is concerned that widely used herbicides will contaminate surface and groundwater. Alternative ways to control weeds in field crops are needed to reduce or prevent herbicide contamination of surface and groundwater. A new between-row-mowing weed management system that consists of band-applied herbicides over crop rows + two or more between-row mowings was tested in G. max over 6 yr in Missouri. Mowing weeds close to the soil surface two or more times between crop rows killed or suppressed annual grass and broadleaf weeds, chiefly Setaria faberi, Ambrosia artemisiifolia, and Amaranthus spp., if properly timed. Shading by crop canopy closure contributed to weed suppression in this weed management system. G. max yield also could not be distinguished from weed-free check plots and was greater than the weedy check plots. Herbicide use was reduced 50% by banding because only 50% of the field area was sprayed. The between-row-mowing weed management system may have use in environmentally sensitive areas to help reduce soil erosion or water contamination by herbicides.

L’usinage robotisé, nouveau challenge de la robotique industrielle, nécessite à la fois rigidité et précision du moyen de production. C’est pourquoi cette pratique particulière du détourage des composites était réservée jusqu’alors aux machines-outils à commande numérique. Cet article propose de démontrer, qu’à partir d’une connaissance des phénomènes de coupe liés aux procédés et de la modélisation des caractéristiques comportementales du robot, il est possible d’optimiser l’exploitation des cellules robotisées. Cette première étude porte sur le cas spécifique du détourage des pièces composites. D’un côté, le robot a été modélisé et ses paramètres de raideur ont été identifiés. De l’autre côté, les conditions de coupe optimales permettant de respecter l’intégrité matière et d’assurer la productivité souhaitée ont été déterminées. Les efforts d’usinage ont alors été relevés. À partir de ces deux études parallèles, les déformations du robot, pour un placement donné de la pièce dans son espace de travail, ont pu être déterminées. Par la suite, ces déformations peuvent être limitées en plaçant judicieusement la tâche dans le volume de la cellule robotisée. Cette solution simple permet de réduire significativement les déformations observées, notamment dans le cas de procédés sollicitant fortement le robot, et ce sans modifier sa commande.

In this article, we show how tests of nonlinear serial dependence can be applied to high-frequency time series data that exhibit high volatility, strong mean reversion, and leptokurtotis. Portmanteau correlation, bicorrelation, and tricorrelation tests are used to detect nonlinear serial dependence in the data. Trimming is used to control for the presence of outliers in the data. The data that are employed are 161,786 half-hourly spot electricity price observations recorded over nearly a decade in the wholesale electricity market in New South Wales, Australia. Strong evidence of nonlinear serial dependence is found and its implications for time series modeling are discussed.