On the stabilization of bilinear systems via constant feedback

We study the problem of stabilization of a bilinear system via a constant feedback. The question reduces to an eigenvalue problem on the pencil A+α0B of two matrices. Using the idea of simultaneous triangularization of the matrices involved, some easily checkable conditions for the solvability of this question are obtained. Algorithms for checking these conditions are given and illustrated by a few examples

Aangewende hoeveelheid dierlijke mest in de akkerbouw

Akkerbouwers passen ten aanzien van fosfaat uit dierlijke mest vooral bouwplanbemesting toe: de mest wordt toegediend op de gewasgroep (consumptie- en fabrieksaardappelen en tuinbouw open grond) die dierlijke mest het beste kan gebruiken

Olympic Fever! From Beijing to Vancouver and Back

The Vancouver 2010 Winter Olympics are now over, and most of the athletes, media, and tourists have left my home city. If the media (particularly British media) began by focusing primarily on negative issues, the drama of national teams, and individual athletes and overall medal counts seemed to drown out the naysayers, much as in Beijing two years ago. Both host countries came off as excellent hosts, and both host countries carried home unprecedented numbers of medals. If for China their Olympics had been a coming out party, an end to a century of general humiliation, for Canada these games were seen as an end to the humiliation of mediocrity: for having failed to win a single gold medal on home turf after twice hosting, in 1976 the Summer Games (Montreal) and in 1988 the Winter Games (Calgary). Canada, known as a country of nice people (A Fair Country, as John Raulston Saul recently called it in the title of his new book), has spent much of its history deferring to others, so when the Canadian Olympic Committee announced the “Own the Podium” program, investing $22.3 million dollars last year in winter sports training, Canadians and non-Canadians were surprised. Although Canada did not win the greatest number of medals, it finished third overall and set an Olympic record for the greatest number of gold medals ever won by a country in a winter Olympics. In 2008, China also dominated in gold medals without completely dominating in total medals. In both cases the extra investment and attention given the Olympics was judged to be important by some, and criticized by others

Lyapunov Exponents of Two Stochastic Lorenz 63 Systems

Two different types of perturbations of the Lorenz 63 dynamical system for Rayleigh-Benard convection by multiplicative noise -- called stochastic advection by Lie transport (SALT) noise and fluctuation-dissipation (FD) noise -- are found to produce qualitatively different effects, possibly because the total phase-space volume contraction rates are different. In the process of making this comparison between effects of SALT and FD noise on the Lorenz 63 system, a stochastic version of a robust deterministic numerical algorithm for obtaining the individual numerical Lyapunov exponents was developed. With this stochastic version of the algorithm, the value of the sum of the Lyapunov exponents for the FD noise was found to differ significantly from the value of the deterministic Lorenz 63 system, whereas the SALT noise preserves the Lorenz 63 value with high accuracy. The Lagrangian averaged version of the SALT equations (LA SALT) is found to yield a closed deterministic subsystem for the expected solutions which is found to be isomorphic to the original Lorenz 63 dynamical system. The solutions of the closed chaotic subsystem, in turn, drive a linear stochastic system for the fluctuations of the LA SALT solutions around their expected values.Comment: 19 pages, 4 figures, comments always welcome

Beijing Olympics 2008: The View from Vancouver (host to Winter 2010 Olympics)

It is interesting to note the similarities between criticisms of Olympic preparation in Vancouver and Beijing. Although the famously beautiful city of Vancouver is still two years away from hosting the winter Olympics in conjunction with the mountain village of Whistler, we are already running into the standard problems and criticisms familiar to Olympic planners of the past few decades. While air quality and the national human rights record are not likely to be the major issues for Vancouver, other themes show up on a regular basis in the local press, including cost overruns, natural disasters, transportation problems, and the potential irreversibility of turning the city into a virtual police state. Last week’s closure of the highway and rail links between Vancouver and Whistler due to a massive landslide served to show the vulnerability of the “Sea-to-Sky Highway” which connects Vancouver to its world-class winter playground (map). Although the Olympics claim to bring people together to celebrate the best in sport apart from politics, the clear links between corporate sponsorships and nationalism as a distraction from the increasing gap between rich and poor in countries like China and Canada are only too obvious in the difference between those who can afford tickets and those who must be content to watch events on television. As in Beijing, many Vancouver residents feel that the Olympics will only exacerbate the problem of housing prices for lower and middle-income earners. The city government reneged on early promises for increasing social housing, so some critics claim there will be more homeless people than athletes for 2010. Perhaps the most interesting Olympic-related story of the past few days in Vancouver is the announcement by the head of Vancouvers Olympic Committee that Vancouver’s Olympics will not organize an international torch relay so they can avoid the kind of protests that marred China’s relay in London and Paris. Perhaps that is as it should be, given the rather monumental job of overcoming the apathetic attitude of many Canadians toward Olympic events unrelated to gold medals in hockey

Verkleining veestapel treft hele keten

Een manier om de milieubelasting van de veehouderij aan te pakken is krimp van de veestapel. Wordt voor die weg gekozen, dan zijn de gevolgen voor werkgelegenheid en inkomens in de sector fors, blijkt uit onderzoeken van het LEI. Met een systeem van verhandelbare emissierechten wordt de economische schade iets kleiner

Ammoniakemissie uit de landbouw tussen 1997 en 2007

De ammoniakemissie uit de landbouw is in de periode 1997-2007 gedaald tot een niveau van 115-120 miljoen kg. De EU-doelstelling voor Nederland van 114 miljoen kg in 2010 is daarmee bijna bereikt. De ammoniakemissie wordt jaarlijks gepubliceerd in de milieubalans en het milieucompendium

Synthese monitoring mestmarkt 2008

Voor het derde jaar op rij is de aanvoer en de afzet van dierlijke mest via de mestmarkt in Nederland bepaald. Dit is gedaan op verzoek van het ministerie van Landbouw, Natuur en Voedselkwaliteit (LNV). De bepaling gebeurt door modelberekeningen met het model MAMBO, analyse van mestvervoersbewijzen en door enquêtes en de analyse van artikelen in tijdschriften over de mestmarkt. Dit rapport geeft een synthese van de resultaten over 2008. De mestproductie in 2008 is geschat op 170 miljoen kg fosfaat (P2O5) en 384 miljoen kg stikstof (N), waarvan 92 miljoen kg fosfaat zal worden afgezet op de bedrijven waar de mest werd geproduceerd. De resterende hoeveelheid zal naar verwachting worden getransporteerd naar andere landbouwbedrijven en naar bestemmingen buiten de Nederlandse landbouw (export, verwerking en particulieren/ hobbybedrijven). De export van dierlijke mest in de eerste 4,5 maand van 2008 was groter dan in dezelfde periode van 2007 (+11% fosfaat). De afzet naar de akkerbouw stabiliseert de laatste drie jaar. Trefwoorden: dierlijke mest, mestmarkt, stikstof, fosfaa