Optimal linear estimation and data fusion

©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Optimal mean square linear estimators are determined for general uncorrelated noise. We allow the noise variance matrix in the observation process to be singular. This requires properties of generalized inverses which are developed in Section II. The proofs appear to be new. When there are two observation sequences the optimal method of recursively fusing the two is determined. We derive a new formula for the covariance of the two estimates which then provides exact dynamics for a fused estimate.Elliott, R.J. ; van der Hoek, J

The evolution of the stellar populations in low surface brightness galaxies

We investigate the star formation history and chemical evolution of low surface brightness (LSB) disk galaxies by modelling their observed spectro-photometric and chemical properties using a galactic chemical and photometric evolution model incorporating a detailed metallicity depen dent set of stellar input data. For a large fraction of the LSB galaxies in our sample, observed properties are best explained by models incorporating an exponentially decreasing global star formation rate (SFR) ending at a present-day gas fraction (M_{gas}/(M_{gas}+M_{stars}) = 0.5 for a galaxy age of 14 Gyr. For some galaxies small amplitude star formation bursts are required to explain the contribution of the young (5-50 Myr old) stellar population to the galaxy integrated luminosity. This suggests that star formation has proceeded in a stochastic manner. The presence of an old stellar population in many late-type LSB galaxies suggests that LSB galaxies roughly follow the same evolutionary history as HSB galaxies, except at a much lower rate. In particular, our results imply that LSB galaxies do not form late, nor have a delayed onset of star formation, but simply evolve slowly.Comment: To be published in A&

A deterministic discretisation-step upper bound for state estimation via Clark transformations

Copyright © 2004 Hindawi Publishing CorporationWe consider the numerical stability of discretisation schemes for continuous-time state estimation filters. The dynamical systems we consider model the indirect observation of a continuous-time Markov chain. Two candidate observation models are studied. These models are (a) the observation of the state through a Brownian motion, and (b) the observation of the state through a Poisson process. It is shown that for robust filters (via Clark's transformation), one can ensure nonnegative estimated probabilities by choosing a maximum grid step to be no greater than a given bound. The importance of this result is that one can choose an a priori grid step maximum ensuring nonnegative estimated probabilities. In contrast, no such upper bound is available for the standard approximation schemes. Further, this upper bound also applies to the corresponding robust smoothing scheme, in turn ensuring stability for smoothed state estimates.W. P. Malcolm, R. J. Elliott, and J. van der Hoe

Use of untreated wastewater in peri-urban agriculture in Pakistan: risks and opportunities

Water reuse / Waste waters / Water quality / Groundwater / Irrigation practices / Soil properties / Environmental effects / Conjunctive use / Pakistan / Haroonabad

Ontwikkeling en implementatie van geïntegreerde bestrijding in zomerbloemen : toepassing van beschikbare producten en ontwikkeling van nieuwe natuurlijke vijanden

In 2008 en 2009 werden loslatingen verricht van de roofmijten Neoseiulus cucumeris en Amblyseius andersoni, soms aangevuld met Phytoseiulus persimilis, in de zomerbloemen rozenbottel, chrysant, Veronica, Alchemilla en Delphinium. Hierbij bleek dat roofmijten zich niet in alle gewassen in gelijke mate vestigen. In Alchemilla en Delphinium bleek al spontaan Neoseiulus cucumeris voor te kunnen komen. Als in deze gewassen nog geen roofmijten voorkomen, zal introductie van N. cucumeris zeker slagen, mits er geen breedwerkende middelen worden toegepast. Vooral Alchemilla bleek een goede roofmijtenplant te zijn. Behalve Neoseiulus cucumeris werden ook andere soorten gevonden. Roofmijten die in de handel zijn tegen spint, Phytoseiulus persimilis en Neoseiulus californicus, vestigen zich eveneens goed in dit gewas, in tegenstelling tot Amblyseius andersoni. Verder kunnen spontaan andere natuurlijke vijanden van plagen voorkomen: roofwantsen, gaasvliegen en galmuggen. Trips nam in beide jaren af gedurende de teelt of bleef op een laag niveau. Neoseiulus alpinus is een roofmijt, die eerder is verzameld van Alchemilla en in kweek genomen. Een loslating van deze roofmijt in Alchemilla slaagde in 2008 niet, maar in 2009 wel. In Delphinium was in 2008 vanaf het begin van de waarnemingen Neoseiulus cucumeris in het gewas aanwezig. Na introductie van Amblyseius andersoni werd ook deze soort teruggevonden. Spint kwam in 2008 niet tot ontwikkeling. Buiten de proef kwam plaatselijk cyclamenmijt voor. In 2009 werd in Delphinium zwavel verdampt tegen echte meeldauw. Er was geen goede vestiging van roofmijten in het gewas, ook niet van de roofmijt Phytoseiulus persimilis, waardoor chemische bestrijding van spint noodzakelijk was. In Veronica, chrysant en rozenbottel kwamen in vergelijking met Alchemilla en Delphinium minder roofmijten voor. Trips en spint waren in 2008 en 2009 geen probleem in Veronica, chrysant en rozenbottel. Op rozenbottel kwam zonder introductie Neoseiulus cucumeris voor. Andere soorten roofmijten, die soms spontaan optraden waren Neoseiulus reductus in Delphinium, Amblyseius graminis in Alchemilla en chrysant, en roofmijten die tot een andere groep (Bdelloidea) behoren, met name op chrysant en Veronica

The functional role of somatostatin receptor subtypes in pituitary adenomas

The main subject of the current thesis is the role of somatostatin (SRIF) receptors subtype 2 and 5 in the patho-physiological regulation of GH and ACTH release from human pituitary adenomas. The sst expression pattern in both types of pituitary adenomas is evaluated with respect to the inhibitory effects by SRIF-analogs on hormone secretion from the primary cultured tumor cells. The novel multiligand SOM230, compared with the current clinically available SRIF-analog OCT, is evaluated both for its clinical potential in the medical treatment of acromegaly, as well for in vitro for its potential in the medical treatment in patients with Cushing’s disease. SOM230, together with sst-selective analogs and chimeric molecules, targeting the sst2, sst5 and Dopamine D2 Receptor, are used as tools to retrieve insights with respect to the functional interplay between sst2, sst5 and D2R in the regulation of adenylyl cyclase activity as well the susceptibility of sst receptors to undergo ligand-induced adaptation, i.e. tachyphylaxis, of inhibition of adenylyl cyclase activity by SRIF-analogs

The CLEANED Approach for Flagging and Addressing Environmental Issues

While livestock presents an important livelihood strategy for many smallholders, it is also held responsible for important environmental impacts. In this paper, we used an online survey to identify the perceptions of global livestock experts on environmental impacts of livestock and how these might be tackled. We then explored how the CLEANED environmental ex-ante assessment tool (Comprehensive Livestock Environmental Assessment for improved Nutrition, a secured Environment and sustainable Development = CLEANED) responds to this and how it can be used to influence decision making towards more environmentally-friendly livestock production. According to the survey, there was general agreement between researchers, development practitioners and policy makers alike that livestock production systems are at risk of global environmental change while at the same time contributing to it. The major risks are perceived to be climate-related. The major impacts associated with livestock production, on the other hand, are considered to be land-related (degradation and competition for land), closely followed by pressure on water and GHG emissions. More sustainable livestock production practices are cited as most promising to reducing livestock’s environmental impact. The preferred technologies include managed grazing, improved pastures, silvo-pastoral systems and planted forages. A lack of rapidly available, site- and system-specific knowledge about such solutions and their potential environmental impacts are considered an important barrier to their successful implementation. The CLEANED environmental ex-ante assessment model aims to fill part of this gap. It can compare the relevant environmental impact indicators of the different solutions brought forward. The model has also been designed to be flexible when applied to a wide variety of contexts and provide systems-specific results. The expert survey further revealed that researchers, development practitioners and policy makers all based decisions on information, obtained from a variety of sources such as journal papers, internet searches and professional networks. The importance of journal papers, however, decreases as an information source from researchers over policy makers to development practitioners, while the use of professional networks and internet searches increases for these groups. This finding points to the importance of the participatory approach taken by the CLEANED team and the need to present results in appropriate multi-stakeholder forums and targeted internet posts. Further recommendations are made for increasing the use of the tool, i.e. making the outputs from the tool easier to interpret and training a variety of stakeholders in its use

Alternate wet/dry irrigation in rice cultivation: a practical way to save water and control malaria and Japanese encephalitis?

Water management / Water scarcity / Water use efficiency / Water conservation / Irrigated farming / Waterborne diseases / Rice / Malaria / Disease vectors / Productivity / Flood irrigation / Environmental control / Climate / China / East Africa / India / Indonesia / Japan / Philippines / Portugal / USA

Agent Programming with Declarative Goals

A long and lasting problem in agent research has been to close the gap between agent logics and agent programming frameworks. The main reason for this problem of establishing a link between agent logics and agent programming frameworks is identified and explained by the fact that agent programming frameworks have not incorporated the concept of a `declarative goal'. Instead, such frameworks have focused mainly on plans or `goals-to-do' instead of the end goals to be realised which are also called `goals-to-be'. In this paper, a new programming language called GOAL is introduced which incorporates such declarative goals. The notion of a `commitment strategy' - one of the main theoretical insights due to agent logics, which explains the relation between beliefs and goals - is used to construct a computational semantics for GOAL. Finally, a proof theory for proving properties of GOAL agents is introduced. Thus, we offer a complete theory of agent programming in the sense that our theory provides both for a programming framework and a programming logic for such agents. An example program is proven correct by using this programming logic