Optimal controllers for finite wordlength implementation

When a controller is implemented in a digital computer, with A/D and D/A conversion, the numerical errors of the computation can drastically affect the performance of the control system. There exists realizations of a given controller transfer function yielding arbitrarily large effects from computational errors. Since, in general, there is no upper bound, it is important to have a systematic way of reducing these effects. Optimum controller designs are developed which take account of the digital round-off errors in the controller implementation and in the A/D and D/A converters. These results provide a natural extension to the Linear Quadratic Gaussian (LQG) theory since they reduce to the standard LQG controller when infinite precision computation is used. But for finite precision the separation principle does not hold

LHC Civil Engineering Construction Contracts: Cost Monitoring and Budget Forecasting

The Civil Engineering project for the LHC is estimated at 350 MCHF, of which about 316 MCHF is for the construction contracts. These contracts are based on a system of remeasurement whereby the consultant estimates the quantities required for the construction of each structure and the contractor commits himself to the unit price, which define the initial tender price. There are many factors that affect the final price for these contracts, from increases or decreases in quantities of the estimated amounts in the original bill of quantities to variations to the contract. This paper will look at how these factors change costs at the individual level of a structure to the overall costs of the contract. It will look at how the Civil Engineering Group monitors these changes to calculate cash flows and final costs and how this information is used as a basis for budget forecasts

A Graphical Solution for Espaces Verts

'Espaces Verts' is responsible for the landscaping of the green areas, the cleaning of the roads, pavements, and car parks on the CERN site. This work is carried out by a contracting company. To control the work previously, there was a database of all the areas included in the contract and paper plans of the site. Given the size of the site the ideal solution was considered to be a visual system which integrates the maps and the database. To achieve this, the Surveying Department's graphical information system was used, linking it to the database for Espaces Verts, thus enabling the presentation of graphical thematic queries. This provides a useful management tool, which facilitates the task of ensuring that the contracting company carries out the work according to the agreed planning, and gives precise measurement of the site and thus of the contract. This paper will present how this has been achieved

ST LHC Budget Follow-up

The ST division is deeply implicated in the LHC project, with a budget of more than 20% of the overall cost of the project. It is therefore important to monitor future estimates, the actual situation and to see where there are divergences between the two. A database has been created presenting the figures for each contract, group, and for the division as a whole. Despite the various types of contract management, the system presents the results in a uniform manner. It allows the initial, present and future situations to be easily reviewed. This highlights any problem areas, facilitates decision-making and enables us to inform the hierarchy of any changes that may have occurred

Testing and evaluation of Dacron parachute elements after exposure to ethylene oxide and simulated package loading and heat cycle

Testing Dacron parachute components and assemblies by exposure to ethylene oxide sterilization, simulated package loading, and heat cycl

Does Weight Status Impact Metabolic Health in Adolescents When Controlling for Physical Fitness?

Purpose: To determines whether adolescents who are fit with overweight/obesity are similar in their metabolic profile to adolescents who are fit and normal weight. Methods: Adolescents participated in 3 sessions: (1) resting vitals and anthropometrics; (2) maximal aerobic treadmill test () to determine physical fitness; and (3) dual-energy x-ray absorptiometry and fasting laboratory draw for analysis of insulin, glucose, high-density lipoprotein, triglycerides, and C-reactive protein. Results: Of the 30 fit adolescents who are normal weight and 16 adolescents who are fit and overweight/obese (OW/OB), metabolic syndrome was apparent in 1 adolescent who are normal weight and 4 adolescents who are OW/OB. Metabolic syndrome severity was positively associated with body mass index, waist circumference, total body fat, insulin resistance, and C-reactive protein but inversely associated with peak relative, but not lean . Conclusions: Despite good physical fitness, adolescents who are OW/OB demonstrated greater metabolic syndrome than adolescents who are normal weight. Future intervention research is necessary to explore the relation between physical fitness and metabolic syndrome

Is There a Sex Difference in the Age of Elite Marathon Runners?

Purpose: The purposes of this study were to determine i) if there is a sex difference in the age of the elite marathon runners and ii) if the sex difference in performance altered across the years that women have participated in the marathon. Methods: Age at time of competition and running times of the first five placed male and female runners who competed in the seven marathons of the World Marathon Majors Series were analyzed. Data from as many years as was available online were retrieved so that 410 men and 410 women were included in the analysis. The marathons and years included the Berlin (1999–2009), Boston (2000–2009), Chicago (1997–2009), London (2001–2009), New York City (1990–2009), International Athletic Association Federation World Championship (1983, 1987, and every 2 yr from 1991), and Olympic (every 4 yr since 1984) marathons. Results: Women were older than men (mean ± SD = 29.8 ± 4.2 vs 28.9 ± 3.8 yr), but for only two of the seven marathons, the Chicago and the London marathons (P \u3c 0.05): the sex difference in age was not consistent across the years. There was no sex difference in age for the Berlin, Boston, New York City, World Championship, and Olympic marathons. Men were faster than women (11.6% ± 1.8%). The sex difference in running velocity varied across marathons (least for the World Championships, 10.2%) and also across years, but not systematically. This sex difference in running velocity increased from first to fifth place across all marathons. Conclusions: These data indicate that men and women physiologically peak at a similar age in marathon running performance. The sex difference in performance of elite marathon runners varied across years but has not systemically decreased or varied since the 1980s

The case for Tai Chi in the repertoire of strategies to prevent falls among older people

Falls among older people is a global public health issue. In this article, Dr Samuel Nyman of Bournemouth University Dementia Research Institute, and Professor Dawn Skelton, Institute for Applied Health Research, Glasgow Caledonian University highlight the effectiveness of Tai Chi as an alternative strategy to physiotherapy to combat this issue