Off-road mobile robot control: An adaptive approach for accuracy and integrity

International audienceThis paper proposes an algorithm dedicated to the control of off-road mobile robots at high speed. Based on adaptive and predictive principles, it first proposes a control law to preserve a high level of accuracy in the path tracking problem. Next, the dynamic model used for grip condition estimation is considered to address also robot integrity preservation thanks to the velocity limitation

Open Skies

This open access book on the history of the National Radio Astronomy Observatory covers the scientific discoveries and technical innovations of late 20th century radio astronomy with particular attention to the people and institutions involved. The authors have made extensive use of the NRAO Archives, which contain an unparalleled collection of documents pertaining to the history of radio astronomy, including the institutional records of NRAO as well as the personal papers of many of the pioneers of U.S. radio astronomy. Technical details and extensive citations to original sources are given in notes for the more technical readers, but are not required for an understanding of the body of the book. This book is intended for an audience ranging from interested lay readers to professional researchers studying the scientific, technical, political, and cultural development of a new science, and how it changed the course of 20th century astronomy

Use of the Grazing Animal in Forage Breeding

The objective of these studies was to determine, in the context of a forage breeding program, the effect of cattle grazing on survival of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and tall fescue (Festuca arundinacea Schreb.). Different cultivars of each species were compared in grazed and ungrazed areas. Results consistently demonstrated that grazing reduced plant stands when compared to ungrazed conditions for each species tested. In alfalfa, however, cultivars developed for grazing tolerance showed much better grazing survival. Infection with the fungal endophyte, Acremonium coenophialum Morgan-Jones & Gams, likewise substantially increased grazing survival in tall fescue. These experiments further demonstrate that cultivar selection and testing needs to be accomplished with the grazing animal to properly assess pasture potential. Selection from elite germplasm under these conditions should probably be practiced as early as possible in the breeding program for species with poor pasture persistence

Extending Utilization of Georgia 5 Tall Fescue in the Lower Southeastern United States

In the southeastern United States, warm season perennial grasses such as bermudagrass (Cynodon dactylon [L.]Pers.) and bahiagrass (Paspalum notatum Flugge) predominate permanent pastures. During dormancy, winter annuals are either over-seeded on permanent pastures or grown on prepared seedbeds for winter pasturing of animals. In addition, cattlemen feed hay cut from warm-season grass production. Cattleman and hay producers have lacked a dependable perennial cool season grass that could be utilized in addition to or in place of winter annuals or hay. High temperatures, pests, droughty conditions and competition from warm season species undermine the persistence of cool season grasses. A recently developed tall fescue (Festuca arundinacea Schreb), ‘Georgia-5’ was released as the first persistent cultivar for the coastal plains region of the lower southeastern USA. Research studies indicated that Georgia 5 can be interseeded into warm season perennial grasses as far south as north Florida and persist under winter grazing as a permanent winter pasture for at least three years. Grower interest and acceptance has been good. On-farm Cooperative Extension Service demonstrations have shown that when properly managed, Georgia 5 can persist under interseeded and monoculture conditions, provide excellent grazing and reduce winter supplemental feed requirements

New active safety device dedicated to light all-terrain vehicle stability: Application to quad bike and off-road mobile robot

International audienceAccording to their specific geometric and dynamic characteristics (small weight, huge reachable speeds ), All-Terrain Vehicles (ATVs - as quad bikes) and off-road mobile robots are very compact and driveable. They permit to realize extra agricultural tasks (spreading, spraying ) in an easier way than using once more a heavy farm tractor. However such vehicles require highly accurate control laws, able to preserve their stability even at high speed. In this paper, the prevention of off-road vehicle and mobile robot rollover are addressed by using a new active safety device. It consists in using Predictive Functional Control (PFC) so as to compute, on-line, the maximum vehicle velocity, compatible with a safe motion over some horizon of prediction, and can be applied, if needed, to the vehicle actuator to prevent from rollover. The capabilities of the proposed device are demonstrated and discussed thanks to both advanced simulations and real experimentation

Open Skies

This open access book on the history of the National Radio Astronomy Observatory covers the scientific discoveries and technical innovations of late 20th century radio astronomy with particular attention to the people and institutions involved. The authors have made extensive use of the NRAO Archives, which contain an unparalleled collection of documents pertaining to the history of radio astronomy, including the institutional records of NRAO as well as the personal papers of many of the pioneers of U.S. radio astronomy. Technical details and extensive citations to original sources are given in notes for the more technical readers, but are not required for an understanding of the body of the book. This book is intended for an audience ranging from interested lay readers to professional researchers studying the scientific, technical, political, and cultural development of a new science, and how it changed the course of 20th century astronomy

Evolution of psychosocial factors at work in a French region

Background : Psychosocial factors at work (PFW) can be defined as all non-physicochemical occupational risks. Several epidemiological models have been proposed to measure PFW, but one of the most widely used is Karasek’s model. Aims : To determine whether psychosocial factors, evaluated by Karasek’s questionnaire, had increased in a cohort of workers. Methods : A random sample of workers in the Pays de la Loire region of France, who could be considered representative of the region’s population of salaried workers, filled in a self-administered questionnaire, including Karasek’s self-administered questionnaire, in 2002–05 and 2007–09. Karasek’s questionnaire can be used to study three psychosocial dimensions (psychological demand, decision latitude and social support in the workplace) in workers in order to define two high-risk situations for their health: ‘Job Strain’ and ‘Iso Strain’. Changes in job strain and iso strain among workers were studied according to the workers’ sociodemographic characteristics and their working conditions. Results : In this sample of 2049 workers, the proportion with iso strain increased between the two periods from 12 to 16%, P < 0.001, mainly among manual workers. Deterioration of Karasek indicators was mainly explained by an increase of the ‘low social support’ dimension (38 versus 49%, P < 0.001). Working conditions such as temporary employment of colleagues and high perceived physical exertion were associated with higher PFW. Conclusions : This study, based on a quantitative and collective model, showed deterioration of working team environments and increased risk for individual mental health in this cohort of French workers in recent years

MADNet: microarray database network web server

MADNet is a user-friendly data mining and visualization tool for rapid analysis of diverse high-throughput biological data such as microarray, phage display or even metagenome experiments. It presents biological information in the context of metabolic and signalling pathways, transcription factors and drug targets through minimal user input, consisting only of the file with the experimental data. These data are integrated with information stored in various biological databases such as NCBI nucleotide and protein databases, metabolic and signalling pathway databases (KEGG), transcription regulation (TRANSFAC©) and drug target database (DrugBank). MADNet is freely available for academic use at http://www.bioinfo.hr/madnet