932 resultados para robotics control actuator feedback linearization


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The National Health and Medical Research Council has funded Professor Wayne Hall (University of Queensland) and Professor Simon Chapman (University of Sydney) for three years 2006-2008, to research aspects of the future of tobacco control, particularly in nations with advanced tobacco control programs like Australia. Dr Coral Gartner (UQ) and Ms Becky Freeman (USyd) are also working on the project. The University of Queensland's eSpace site provides links to papers and data appendices produced by the University of Queensland team on the project. Materials relevant to this project produced by the University of Sydney group are available at the link provided.

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The extensive antigenic variation phenomena African trypanosomes display in their mammalian host have hampered efforts to develop effective vaccines against trypanosomiasis. Human disease management aims largely to treat infected hosts by chemotherapy, whereas control of animal diseases relies on reducing tsetse populations as well as on drug therapy. The control strategies for animal diseases are carried out and financed by livestock owners, who have an obvious economic incentive. Sustaining largely insecticide-based control at a local level and relying on drugs for treatment of infected hosts for a disease for which there is no evidence of acquired immunity could prove extremely costly in the long run. It is more likely that a combination of several methods in an integrated, phased and area-wide approach would be more effective in controlling these diseases and subsequently improving agricultural output. New approaches that are environmentally acceptable, efficacious and affordable are clearly desirable for control of various medically and agriculturally important insects including tsetse. Here, Serap Aksoy and colleagues discuss molecular genetic approaches to modulate tsetse vector competence.

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The possibility of controlling vector-borne disease through the development and release of transgenic insect vectors has recently gained popular support and is being actively pursued by a number of research laboratories around the world. Several technical problems must be solved before such a strategy could be implemented: genes encoding refractory traits (traits that render the insect unable to transmit the pathogen) must be identified, a transformation system for important vector species has to be developed, and a strategy to spread the refractory trait into natural vector populations must be designed. Recent advances in this field of research make it seem likely that this technology will be available in the near future. In this paper we review recent progress in this area as well as argue that care should be taken in selecting the most appropriate disease system with which to first attempt this form of intervention. Much attention is currently being given to the application of this technology to the control of malaria, transmitted by Anopheles gambiae in Africa. While malaria is undoubtedly the most important vector-borne disease in the world and its control should remain an important goal, we maintain that the complex epidemiology of malaria together with the intense transmission rates in Africa may make it unsuitable for the first application of this technology. Diseases such as African trypanosomiasis, transmitted by the tsetse fly, or unstable malaria in India may provide more appropriate initial targets to evaluate the potential of this form of intervention.

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Power system real time security assessment is one of the fundamental modules of the electricity markets. Typically, when a contingency occurs, it is required that security assessment and enhancement module shall be ready for action within about 20 minutes’ time to meet the real time requirement. The recent California black out again highlighted the importance of system security. This paper proposed an approach for power system security assessment and enhancement based on the information provided from the pre-defined system parameter space. The proposed scheme opens up an efficient way for real time security assessment and enhancement in a competitive electricity market for single contingency case

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Little is known about factors effecting plant growth at high pH, with research often limited by the inability to separate nutritional deficiencies and HCO3- toxicity from the direct limitations imposed under high pH conditions. Various methods of controlling dilute nutrient solutions for studies at high pH were investigated. For short-term studies, it was found that a solution without Cu, Fe, Mn and Zn and aerated with CO2 depleted air, greatly reduced nutrient precipitation at high pH, thus eliminating nutritional differences between treatments. Manual pH adjustment and the use of ion exchange resins as pH buffers were unsuitable methods of pH control. However, pH control by automated titration had little effect on solution composition while maintaining constant pH. The system described is suitable for studies in which the pH of the bulk nutrient solution must be maintained. The system was used to examine OH- toxicity in mungbeans (Vigna radiata (L.) Wilczek cv. Emerald), with root length reduced at a bulk solution pH of 8.5 and greater.

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Business process design is primarily driven by process improvement objectives. However, the role of control objectives stemming from regulations and standards is becoming increasingly important for businesses in light of recent events that led to some of the largest scandals in corporate history. As organizations strive to meet compliance agendas, there is an evident need to provide systematic approaches that assist in the understanding of the interplay between (often conflicting) business and control objectives during business process design. In this paper, our objective is twofold. We will firstly present a research agenda in the space of business process compliance, identifying major technical and organizational challenges. We then tackle a part of the overall problem space, which deals with the effective modeling of control objectives and subsequently their propagation onto business process models. Control objective modeling is proposed through a specialized modal logic based on normative systems theory, and the visualization of control objectives on business process models is achieved procedurally. The proposed approach is demonstrated in the context of a purchase-to-pay scenario.

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The dental profession has possessed traditional standards of cross-infection control but the recent expression of real concerns by both the public and the profession over the transmissibility of infectious diseases in the dental surgery has demanded a formalized and extended approach to teaching cross-infection control in the dental curriculum. Clear curriculum content must be formulated within contemporary Workplace Health and Safety Guidelines and the Strategic Plan of the Dental School or academic health centre. The full integration demands that the area is taught as a discrete entity but recognized as an intrinsic part of each clinical encounter. This paper discusses the structure and integration of cross-infection control into the curriculum at the University of Queensland Dental School.

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Interactions between testosterone, estradiol, and inhibin in the control of gonadotrophin secretion in males are poorly understood. Castrated rams were treated with steroid-free bovine follicular fluid (bFF), testosterone, or estradiol and for 7 d (2 x 2 x 2 factorial design). Given independently, none of the exogenous hormones affected follicle-stimulating hormone (FSH) concentrations, but the combination of one or both steroids with bFF reduced FSH secretion. Testosterone and estradiol reduced luteinizing hormone (LH) pulse frequency (there was no synergism), and bFF had no effect. Plasma prolactin concentrations were not affected by any treatment. To locate the central sites of steroid action, castrated rams were bilaterally implanted in the preoptic area (POA), ventromedial nucleus (VMH), or arcuate nucleus (ARC). These implants did not affect FSH or prolactin concentrations, or LH pulse amplitude. The frequency of the LH pulses was not affected by testosterone in any site. Estradiol located in the ARC, but not the POA or VMH, decreased LH pulse frequency. In summary, FSH secretion is controlled by synergistic interactions between inhibin and estradiol or testosterone, whereas GnRH/LH pulse frequency is controlled by testicular steroids. Estradiol acts partly, at least, in the ARC, but the central site of action, testosterone remains unknown.

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Communication skills change with age as a result of sensory deficits, memory loss, and increasing word finding difficulties The Keep on Talking program (L. Hickson, H. Barnett, L. Worrall, & E. Yiu, 1994) was developed to assist older people to develop their own strategies for maintaining communication skills into old age. Two hundred and fifty-two healthy older people were recruited from the community and were assessed on a battery of communication assessments on entry to the study and at 1 year after entry. The experimental group (n = 120) participated in the 5-week group Keep on Talking program run by volunteers A further 130 control subjects were assessed only. The short-term effectiveness of the program was evaluated using a short knowledge based and attitudinal questionnaire and qualitative written feedback. At the I-year follow up, subjects were also asked whether they had taken any action as a result of the project. Results concluded that there was a significant difference between the number of correct questionnaire responses on the knowledge based items and the ratings on the attitudinal items pre- and postprogram questionnaire for the experimental subjects. Qualitative written feedback was positive with many participants remarking on the amount of information that they had acquired. Forty-eight experimental and 69 control subjects (n = 117) were assessed I year later, and there was a significant difference between the groups in terms of the number of subjects who reported having taken action as a result of the program. The Keep on Talking program increased knowledge about communication, produced a positive change in attitude toward the importance of communication, and encouraged participants to take action to maintain their communication skills. Maintaining communication skills may prevent social isolation. This simple 5-hour group program has been effective in empowering participants to maintain. their communication skills as they age.

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The aim of the study was to test a revised conceptualization of the role of coping in adjustment to a low-control stressor-women's adjustment to a failed in vitro fertilization (NF) attempt. Data were collected prior to the IVF treatment (Time I) and twice after the failed NF attempt (1 to 2 weeks after finding out the results, n = 171, and fi weeks later, n = 139). Initial adjustment was assessed at Time I, whereas measures of coping and both self-report and partner ratings of adjustment were obtained at Times ? and 3. As predicted, escapist strategies and problem-management strategies (mainly at Time ?) were associated with poor adjustment, whereas problem-appraisal coping was associated with better adjustment., There was also support for the proposed positive relationship between adjustment and emotional approach coping (on self-report adjustment).

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Two studies demonstrate dissociation between children's understanding of pictorial representations (photos and drawings) and mental representations (beliefs). In Study 1, 37 preschoolers were tested on false belief, appearance-reality, false photo, and false drawing tasks. The false picture tasks were significantly easier, and no correlation was found between children's performances on false belief and false picture tasks. Ln Study 2, 30 children who failed a false belief pretest were randomly assigned to 3 training groups: Belief (trained on false belief tasks), Picture (trained on false picture tasks), or Control (trained on number conservation tasks). Training was conducted in 2 sessions over the course of 2 weeks, tasks were presented and feedback was provided. All children were posttested on theory of mind tasks, false picture tasks, and a number conservation task. The posttest results showed differential patterns of performance, with the Belief group scoring highest on the theory of mind posttests, the Picture group scoring highest on the false picture posttests, and the Control group scoring highest on the number conservation posttest. Results are discussed with respect to competing models of theory of mind development.