A direct adaptive neural command controller design for an unstable helicopter

This paper presents an off-line (finite time interval) and on-line learning direct adaptive neural controller for an unstable helicopter. The neural controller is designed to track pitch rate command signal generated using the reference model. A helicopter having a soft inplane four-bladed hingeless main rotor and a four-bladed tail rotor with conventional mechanical controls is used for the simulation studies. For the simulation study, a linearized helicopter model at different straight and level flight conditions is considered. A neural network with a linear filter architecture trained using backpropagation through time is used to approximate the control law. The controller network parameters are adapted using updated rules Lyapunov synthesis. The off-line trained (for finite time interval) network provides the necessary stability and tracking performance. The on-line learning is used to adapt the network under varying flight conditions. The on-line learning ability is demonstrated through parameter uncertainties. The performance of the proposed direct adaptive neural controller (DANC) is compared with feedback error learning neural controller (FENC).

Laboratory notebooks: a cautionary tale

A mathematician tends to have an intense relationship with treatises – one which is more akin to that of a historian than that of her colleagues in the ‘hard’ sciences. A book may be a century or two old and still be relevant as a source of information or inspiration, well-thumbed textbooks from youth might be still consulted decades later, and fierce arguments rage about relative merits of different treatments of the same subject. And much like any book-lover, a mathematician is forever arguing with herself whether she can afford to buy this volume or the other. When the price label is in dollars or euros and the salary paid in rupees, this last dilemma is particularly acute.

Satellite-derived direct radiative effect of aerosols dependent on cloud cover

Aerosols from biomass burning can alter the radiative balance of the Earth by reflecting and absorbing solar radiation(1). Whether aerosols exert a net cooling or a net warming effect will depend on the aerosol type and the albedo of the underlying surface(2). Here, we use a satellite-based approach to quantify the direct, top-of-atmosphere radiative effect of aerosol layers advected over the partly cloudy boundary layer of the southeastern Atlantic Ocean during July-October of 2006 and 2007. We show that the warming effect of aerosols increases with underlying cloud coverage. This relationship is nearly linear, making it possible to define a critical cloud fraction at which the aerosols switch from exerting a net cooling to a net warming effect. For this region and time period, the critical cloud fraction is about 0.4, and is strongly sensitive to the amount of solar radiation the aerosols absorb and the albedo of the underlying clouds. We estimate that the regional-mean warming effect of aerosols is three times higher when large-scale spatial covariation between cloud cover and aerosols is taken into account. These results demonstrate the importance of cloud prediction for the accurate quantification of aerosol direct effects.

A Method for the Deposition of Transparent Conducting Thin-Films of Tin Oxide

A modified method has been developed for the deposition of transparent semiconducting thin films of tin oxide, involving the chemical vapour phase oxidation of tin iodide. These films show sheet resistances greater than 100 Ω/□ and an average optical transmission in the visible range exceeding 80%. The method avoids uncontrolled contamination, resulting in better reproducibility of the films. The films showed direct and indirect transitions and the possibility of an indirect forbidden transition. X-ray diffraction studies reveal that the films are polycrystalline. The low mobility values of the films have been attributed to the grain boundary scattering effect.

Discussion of “Generalized estimating equations: Notes on the choice of the working correlation matrix”

Objective To discuss generalized estimating equations as an extension of generalized linear models by commenting on the paper of Ziegler and Vens "Generalized Estimating Equations. Notes on the Choice of the Working Correlation Matrix". Methods Inviting an international group of experts to comment on this paper. Results Several perspectives have been taken by the discussants. Econometricians have established parallels to the generalized method of moments (GMM). Statisticians discussed model assumptions and the aspect of missing data Applied statisticians; commented on practical aspects in data analysis. Conclusions In general, careful modeling correlation is encouraged when considering estimation efficiency and other implications, and a comparison of choosing instruments in GMM and generalized estimating equations, (GEE) would be worthwhile. Some theoretical drawbacks of GEE need to be further addressed and require careful analysis of data This particularly applies to the situation when data are missing at random.

From council dog catcher to critical scholar

Carol and I just missed each other in the early 1990s: Carol left Manchester for Australia in 1990, while I an·iv·ed in Manchester from Australia in 1993. Sixteen years later and on the very opposite side of the world, we found ourselves sharing an adjacent room during the 2009 Agri-Food Research Network conference in Auckland. Carol was already an accomplished sociologist; I was a newbie PhD student, presenting on a thesis topic that was only just starting to take shape...

Selective herbicide strategies for use in Australian desmanthus seed crops

Grass and broad-leaved weeds can reduce both yields and product marketability of desmanthus (Desmanthus virgatus) seed crops, even when cultural control strategies are used. Selective herbicides might economically control these weeds, but, prior to this study, the few herbicides tolerated by desmanthus did not control key weed contaminants of desmanthus seed crops. In this study, the tolerance of desmanthus cv. Marc to 55 herbicides used for selective weed control in other leguminous crops was assessed in 1 pot trial and 3 Queensland field trials. One field trial assessed the tolerance of desmanthus seedlings to combinations of the most promising pre-emergent and post emergent herbicides. The pre-emergent herbicides, imazaquin, imazethapyr, pendimethalin, oryzalin and trifluralin, gave useful weed control with very little crop damage. The post-emergent herbicides, haloxyfop, clethodim, propyzamide, carbetamide and dalapon, were safe for controlling grass weeds in desmanthus. Selective post-emergence control of broad-leaved weeds was achieved using bentazone, bromoxynil and imazethapyr. One trial investigated salvaging second-year desmanthus crops from mature perennial weeds, and atrazine, terbacil and hexazinone showed some potential in this role. Overall, our results show that desmanthus tolerates herbicides which collectively control a wide range of weeds encountered in Queensland. These, in combination with cultural weed control strategies, should control most weeds in desmanthus seed crops.

Liver transplantation in children: Experience with the development of an Australian pilot programme. The Queensland Liver Transplantation Programme

Children with end-stage liver disease now form a major sub-group of patients considered suitable for liver transplantation (ltp), and enjoy better survival statistics after transplantation than do adults. Since June 1984, a paediatric ltp programme has been developed in Brisbane with an initial working relationship and ongoing close links with two USA centres (Pittsburgh, and the UCLA Medical Center). Fourteen children with end-stage liver disease have been referred to the Queensland Liver Transplantation Programme for formal assessment. Following frank, informed discussion with their parents, 10 of these children were offered the option of ltp. During the transition stage, two infants with biliary atresia were referred to UCLA at their parents' request and, subsequently, eight children aged from 9 months to 6 years have been placed on a transplant candidacy list in Brisbane. A donor procurement team with access to a Queensland Government jet has been available to cover all mainland States except Western Australia. Six of the children have now had orthotopic ltp (two children at the UCLA Medical Center; four children at the Royal Children's Hospital, Brisbane). One UCLA patient died with a non-functioning graft, and one Brisbane patient died 5 weeks post-transplant with rejection, hepatic artery thrombosis and sepsis. The other four children are alive and well, three with normal liver function and one with unexplained intrahepatic cholestasis, during the 1-20 month follow-up to date. Three further children have died of their liver disease without a donor of an appropriate blood group and size being found, and one patient still awaits a suitable donor. The experience of these authors suggests that ltp is a major advance in the treatment of paediatric liver disease, and that the procedure can be carried out successfully in Australia with initial results comparable with leading overseas centres. The procedure requires the full array of services of a major paediatric tertiary care facility, an intensive team effort with awareness of the special needs of children, and a widespread procurement capability. A major problem for Australia is the procurement of sufficient numbers of optimal paediatric donor livers.

Fernando Pessoan ortonyymi ja heteronyymit modernistis-romanttisena myyttinä

Tutkimuksessani selvitän portugalilaisrunoilija Fernando Pessoan (1888-1935) heteronyymejä ja ortonyymiä modernistis-romanttisena myyttinä. Myytin piirteet paljastuivat Pessoan omia kirjoituksia ja runoja tutkimalla ja käyttämällä apuna Pessoa-tutkimusta. Tutkimusaineistonani ovat Pessoa-ortonyymin Mensagem-runoelma ja ”Autopsykografia”-runo, Álvaro de Campoksen vuonna 1917 Portugal Futurista –lehdessä julkaistu ”Ultimatum”-runomanifesti, Alberto Caeiron ”Guardador de Rebanhos”-runosikermä sekä Ricardo Reisin ”Oodit”-kokonaisuuteen kuuluvat runot: n:ro 59 ”Acima da verdade estão os deuses” (”Totuuden yläpuolella ovat jumalat”, 1914), n:ro 66 ”Olho os campos, Neera” (”Katson peltoja, Neera”, 1917), n:ro 181 ”Amo o que vejo” (”Rakastan sitä mitä näen”, 1934), n:ro 175 ”Estas só. Ninguem o sabe.” (”Olet yksin. Kukaan ei tiedä sitä”, 1933). Tutkimuksessani romanttisen runouden keskeisinä piirteinä pidetään uskoa taiteilijaneroon (geniukseen), mimeettiseen illuusioon (taide tavoittelee ulkoisen todellisuuden toisintamista mahdollisimman autenttisena) ja tekijän ja kokijan eli subjektin ja objektin erottamiseen toisistaan. Käsitänkin modernin runon tutkimuksessani hylänneen monia entisiä käsityksiä ja vastakkainasetteluja muun muassa tekijän ja ulkopuolisen maailman, mielen ja kielen välillä. Näitä moderneja ”rikkomuksia” identifioin ja määrittelen Pessoan heteronyymien runoudessa. Tutkimukseni apukäsitteitä ovat vilpittömyys ja autenttisuus, jotka kuvaavat runoilijan suhdetta itseensä ja muihin ja joita on pohtinut mm. Lionel Trilling teoksessaan Sincerity and authencity. Romanttisessa runoudessa suhde yhteisöön muodostui ensisijaisesti suhteessa omaan itseen, yhtenäiseen minuuteen nojaavan vilpittömyyden kautta, modernissa runoudessa hajanaisuutta ja yksilön suhdetta myös yhteisöön korostavan autenttisuuden avulla. Tutkimuksessani havaitsin, että Pessoa on jo tuotantonsa alusta lähtien kehittänyt tietoisesti modernistis-romanttista myyttiä – päätelmää tukivat niin Pessoan omat kirjoitukset kuin runoanalyysini. Pessoa ennusti ensimmäisen kerran romanttiseen nerotaiteilijaan vertautuvaa ”supra-Camõesia” ”A nova poesia Portuguesa Sociologicamente considerada” –esseessään vuonna 1912. Campoksen ”Ultimatum”-manifestissa puhuja uskoi muutaman useita kymmeniä persoonallisuuksia hallitsevan ”Synteesi-Ihmisen” tai ”supra-Camõesin” ilmestymiseen. ”Synteesi-Ihmisen” oli määrä palauttaa kukoistukseensa lamaantuneessa tilassa ollut Portugalin kirjallisuus uuteen kukoistukseensa. Eräänlaisen perustan koko myytille loi vuotta ennen Pessoan kuolemaa julkaistu Mensagem (suom. Viesti), jossa runoilija esittää saudosistisen ja sebastianistisen perustan. Teixeira de Pascoaesin kehittämä saudosismi näkyy Mensagemissa uskona Portugalin valtion perustajien ja laajentajien – löytöretkeilijöiden – edustamaan voittoisaan lusofoniseen mentaliteettiin, jonka Pessoa asettaa niin kansakunnan, runoilijan kuin ihmisen ihanteeksi. Toinen Mensagemissa esiintyvä myytin rakennusaine on sebastianismi eli usko kuningas Sebastianin (1554-1578) paluuseen. ”Synteesi-Ihminen”/”supra-Camões” oli reinkarnoitunut Sebastian, jonka piti palauttaa kansa ja kulttuuri kukoistukseensa lusofonisen valloittajamentaliteetin avulla. ”Autopsykografia”-runossaan Pessoa esittää puolestaan runoilijaa koskevan modernin poetiikan ongelmineen: esittävyyteen perustuva taide etäännyttää kokijan – taiteilijan – aina väistämättä ensimmäisestä, spontaanista ja luonnollisesta kokemuksesta ja tekee hänestä teeskentelijän ja simulakrumien (Baudrillard), toisen tason merkityksen tuottajan. ”Autopsykografian” moderni poetiikka koskee myös lukijaa, joka ei tavoita runoilijan välittämää merkitystä vaan kolmannen tason merkityksen. ”Autopsykografian” runous- ja ihmiskäsitys on moderni: runoilija on ammattimainen teeskentelijä, lähtökohtaisesti vilpillinen ja epäautenttinen. Pessoa ja Campos edustavat Pessoan objektiivisia heteronyymejä ja myytin modernia puolta. Pessoan subjektiiviset heteronyymit Reis ja Caeiro täydentävät objektiviisia, modernin ihmisen ahdistusta ja levottomuutta ilmaisseita Pessoaa ja Camposta ollen luonteeltaan romanttisia vilpittömyyden kannattajia. Caeiro arvosti näköaistia yli muiden aistien. Hänen tavoitteenaan oli katsoa aina kuin ensimmäistä kertaa, spontaanisti ja välittömästi kuin lapsi. Reis puolestaan korosti harmoniaa jumalten, ihmisten ja luonnon välillä ja uskoi kohtuullisiin aistinautintoihin. Molemmat muodostivat Pessoan myytin romanttisen puolen yhteisessä halussaan hylätä sosiaaliset roolit ja opetukset ja palata kohti yksilöllistä minää. Vilpittömyys ja autenttisuus ovat Caeiron ja Reisin ohjeita runoilijalle ja ihmiselle. Objektiiviset ja subjektiiviset heteronyymit yhdessä muodostavat modernistis-romanttisen myytin, joka kokonaisuudessaan on looginen: objektiiviset heteronyymit esittivät teeskentelyn, vilpillisyyden ja moderniuden ongelmat; subjektiiviset tarjosivat ratkaisua niihin, poisopettelua sosiaalisista rooleista ja rohkeutta mennä kohti omaa yksilöllistä minuutta.

Forest health surveillance methodology in hardwood plantations in Queensland, Australia

Forest health surveillance (FHS) of hardwood plantations commenced in Queensland in 1997 as plantations expanded following a state government planting initiative arising from the national 2020 forest policy vision. The estate was initially characterised by a large number of small plantations (10-50 ha), although this has changed more recently with the concentration of larger plantations in the central coast and South Burnett regions. Due to the disparate nature of the resource, drive- and walkthrough surveys of subsets of plantations have been undertaken in preference to aerial surveys. FHS has been effective in detecting a number of new hardwood pests in Queensland including erinose mites (Rhombacus and Acalox spp.), western white gum plate galler (Ophelimus sp.), Creiis psyllid and bronzing bug (Thaumastocoris sp.), in evaluating their potential impact and assisting in focussing future research efforts. Since 2003 there has been an increased emphasis on training operational staff to take a greater role in identifying and reporting on forest health issues. This has increased their awareness of forest health issues, but their limited time to specifically survey and report on pests and diseases, and high rates of staff turnover, necessitate frequent ongoing training. Consequently, common and widespread problems such as quambalaria shoot blight (Quambalaria pitereka), chrysomelid leaf beetles (mainly Paropsis atomaria) and erinose mites may be under-reported or not reported, and absence data may often not be recorded at all. Comment is made on the future directions that FHS may take in hardwood plantations in Queensland.

Field evaluation of 64 rootstocks for growth and yield of 'Kensington Pride' mango

Despite an abundance of polyembryonic genotypes and the need for rootstocks that improve scion yield and productivity, simultaneous field testing of a wide range of mango (Mangifera indica L.) genotypes as rootstocks has not previously been reported. In this experiment, we examined the growth and yield of 'Kensington Pride' on 64 mango genotypes of diverse origin during the first four seasons of fruit production to identify those worth longer-term assessment. We also recorded morphological characteristics of seedlings of 46 of these genotypes in an attempt to relate these measures to subsequent field performance. Tree canopy development on the most vigorous rootstocks was almost double that on the least vigorous. Growth rates differed by more than 160%. Cumulative marketable yield ranged from 36 kg/tree for the lowest yielding rootstock to 181 kg/tree for the most productive. Yield efficiency also differed markedly among the 64 rootstocks with the best treatment being 3.5 times more efficient than the poorest treatment. No relationship was found between yield efficiency and tree size, suggesting it is possible to select highly efficient rootstocks of differing vigor. Two genotypes ('Brodie' and 'MYP') stood out as providing high yield efficiency with small tree size. A further two genotypes ('B' and 'Watertank') were identified as offering high yield efficiency and large tree size and should provide high early yields at traditional tree spacing. Efforts to relate the morphology of different genotype seedlings to subsequent performance as a rootstock showed that nursery performance of mango seedlings is no indication of their likely behavior as a rootstock. The economic cost of poor yields and low yield efficiencies during the early years of commercial orchard production provide a rationale for culling many of the rootstock treatments in this experiment and concentrating future assessment on the top ~20% of the 64 treatments. Of these, 'MYP', 'B', 'Watertank', 'Manzano', and 'Pancho' currently show the most promise.

Genotypic variation in seedling root architectural traits and implications for drought adaptation in wheat (Triticum aestivum L.)

Root system characteristics are of fundamental importance to soil exploration and below-ground resource acquisition. Root architectural traits determine the in situ space-filling properties of a root system or root architecture. The growth angle of root axes is a principal component of root system architecture that has been strongly associated with acquisition efficiency in many crop species. The aims of this study were to examine the extent of genotypic variability for the growth angle and number of seminal roots in 27 current Australian and 3 CIMMYT wheat (Triticum aestivum L.) genotypes, and to quantify using fractal analysis the root system architecture of a subset of wheat genotypes contrasting in drought tolerance and seminal root characteristics. The growth angle and number of seminal roots showed significant genotypic variation among the wheat genotypes with values ranging from 36 to 56 (degrees) and 3 to 5 (plant-1), respectively. Cluster analysis of wheat genotypes based on similarity in their seminal root characteristics resulted in four groups. The group composition reflected to some extent the genetic background and environmental adaptation of genotypes. Wheat cultivars grown widely in the Mediterranean environments of southern and western Australia generally had wider growth angle and lower number of seminal axes. In contrast, cultivars with superior performance on deep clay soils in the northern cropping region, such as SeriM82, Baxter, Babax, and Dharwar Dry exhibited a narrower angle of seminal axes. The wheat genotypes also showed significant variation in fractal dimension (D). The D values calculated for the individual segments of each root system suggested that, compared to the standard cultivar Hartog, the drought-tolerant genotypes adapted to the northern region tended to distribute relatively more roots in the soil volume directly underneath the plant. These findings suggest that wheat root system architecture is closely linked to the angle of seminal root axes at the seedling stage. The implications of genotypic variation in the seminal root characteristics and fractal dimension for specific adaptation to drought environment types are discussed with emphasis on the possible exploitation of root architectural traits in breeding for improved wheat cultivars for water-limited environments.

Black Sigatoka disease: new technologies to strengthen eradication strategies in Australia

In 2001, an incursion of Mycosphaerella fijiensis, the causal agent of black Sigatoka, was detected in Australia's largest commercial banana growing region, the Tully Banana Production Area in North Queensland. An intensive surveillance and eradication campaign was undertaken which resulted in the reinstatement of the disease-free status for black Sigatoka in 2005. This was the first time black Sigatoka had ever been eradicated from commercial plantations. The success of the eradication campaign was testament to good working relationships between scientists, growers, crop monitors, quarantine regulatory bodies and industry. A key contributing factor to the success was the deployment of a PCR-based molecular diagnostic assay, developed by the Cooperative Research Centre for Tropical Plant Protection (CRCTPP). This assay complemented morphological identification and allowed high throughput diagnosis of samples facilitating rapid decision-making during the eradication campaign. This paper describes the development and successful deployment of molecular diagnostics for black Sigatoka. Shortcomings in the gel-based assay are discussed and the advantages of highly specific real-time PCR assays, capable of differentiating between Mycosphaerella fijiensis, Mycosphaerella musicola and Mycosphaerella eumusae are outlined. Real-time assays may provide a powerful diagnostic tool for applications in surveillance, disease forecasting and resistance testing for Sigatoka leaf spot diseases.

Mechanical performances of track-shaped rebar stiffened concrete-filled steel tubular (SCFRT) stub columns under axial compression

This paper presents a combined experimental, numerical, and theoretical study on the mechanical behaviors of track-shaped concrete-filled steel tubular (SCFRT) stub columns stiffened by rebars under compressive load. A total of 18 track-shaped concrete-filled steel tubular specimens including 12 specimens stiffened by rebars and 6 non-stiffened counterparts are tested, with consideration of parameters including flakiness ratio, concrete strength, and stiffeners. Failure pattern, bearing capacity, and ductility are all analyzed and discussed based on the experimental results. The numerical simulation by finite element (FE) software ABAQUS is also conducted. Based on both experimental and numerical results, theoretical formula to predict the load-bearing capacity of SCFRT stub columns subjected to axial compression loading is established according to the superposition principle of ultimate load-bearing capacity with rational simplification. The proposed theoretical method provides accurate predictions on the load bearing capacity by comparing with experimental results from 18 groups of specimens.

The effects of +Gz force on the bone mineral density of fighter pilots

HYPOTHESIS Bone is a metabolically active tissue which responds to high strain loading. The purpose of this study was to examine the bone response to high +Gz force loading generated during high performance flying. METHODS The bone response to +Gz force loading was monitored in 10 high performance RAAF pilots and 10 gender-, age-, height-, weight-matched control subjects. The pilots were stationed at the RAAF base at Pearce, Western Australia, all completing the 1-yr flight training course. The pilots flew the Pilatus PC-9 aircraft, routinely sustaining between 2.0 and 6.0 +Gz. Bone mineral density (BMD) and bone mineral content (BMC) were measured at baseline and 12 mo, using the Hologic QDR 2000+ bone densitometer. RESULTS After controlling for change in total body weight and fat mass, the pilots experienced a significant increase in BMD and BMC for thoracic spine, pelvis, and total body, in the magnitude of 11.0%, 4.9%, and 3.7%, respectively. However, no significant changes in bone mineral were observed in the pilots lumbar spine, arms or legs. The control group experienced a significant decrease in pelvic BMC, with no other bone mineral changes observed at any site. CONCLUSIONS These findings suggest that site specific BMD is increased in response to high +Gz forces generated during high performance flying in a PC-9.