989 resultados para Partial feedback linearisation


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Call control features (e.g., call-divert, voice-mail) are primitive options to which users can subscribe off-line to personalise their service. The configuration of a feature subscription involves choosing and sequencing features from a catalogue and is subject to constraints that prevent undesirable feature interactions at run-time. When the subscription requested by a user is inconsistent, one problem is to find an optimal relaxation, which is a generalisation of the feedback vertex set problem on directed graphs, and thus it is an NP-hard task. We present several constraint programming formulations of the problem. We also present formulations using partial weighted maximum Boolean satisfiability and mixed integer linear programming. We study all these formulations by experimentally comparing them on a variety of randomly generated instances of the feature subscription problem.

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Using a unique set of data and exploiting a large-scale natural experiment, we estimate the effect of real-time usage information on residential electricity consumption in Northern Ireland. Starting in April 2002, the utility replaced prepayment meters with advanced meters that allow the consumer to track usage in real-time. We rely on this event, account for the endogeneity of price and payment plan with consumption through a plan selection correction term, and find that the provision of information is associated with a decline in electricity consumption of 11-17%. We find that the reduction is robust to different specifications, selection-bias correction methods and subsamples of the original data. The advanced metering program delivers reasonably cost-effective reductions in carbon dioxide emissions, even under the most conservative usage reduction scenarios.

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Most tutors in architecture education regard studio-based learning to be rich in feedback due to is dialogic nature. Yet, student perceptions communicated via audits such as the UK National Student Survey appear to contradict this assumption and challenge the efficacy of design studio as a truly discursive learning setting. This paper presents findings from a collaborative study that was undertaken by the Robert Gordon University, Aberdeen, and Queen’s University Belfast that develop a deeper understanding of the role that peer interaction and dialogue plays within feedback processes, and the value that students attribute to these within the overall learning experience.

The paper adopts a broad definition of feedback, with emphasis on formative processes, and including the various kinds of dialogue that typify studio-based learning, and which constitute forms of guidance, direction, and reflection. The study adopted an ethnographic approach, gathering data on student and staff perceptions over the course of an academic year, and utilising methods embracing both quantitative and qualitative data.

The study found that the informal, socially-based peer interaction that characterises the studio is complementary to, and quite distinct from, the learning derived through tutor interaction. The findings also articulate the respective properties of informal and formally derived feedback and the contribution each makes to the quality of studio-based learning. It also identifies limitations in the use or value of peer learning, understanding of which is valuable to enhancing studio learning in architecture.

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This report presents the results of a collaborative project between Queens University, Belfast and the Robert Gordon University, Aberdeen, and builds on a dialogue initiated during Session 2009-10 through which course guidance and feedback received by students was identified as an area requiring deeper understanding in order to enhance current practice

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The outcomes of school-based counseling incorporating the Partners for Change Outcome Monitoring System (PCOMS) were evaluated using a cohort design, with multilevel modeling to identify predictors of change. Participants were 288 7-11 year olds experiencing social, emotional or behavioral difficulties. The intervention was associated with significant reductions in psychological distress, with a pre-post effect size (d) of 1.49 on the primary outcome measure and 88.7% clinical improvement. Greater improvements were found for disabled children, older children, and where CBT methods were used. The findings provide support for the use of systematic feedback in therapy with children.

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Persistence of the asymmetrical tonic neck reflex (ATNR) was examined in children with partial hearing (aged 6–12 years). Core literacy skills were also assessed. Three groups of children were selected from three schools with special units for children with partial hearing. All children completed an upright ATNR test protocol and standardized tests of reading and spelling. Children with partial hearing had significant levels of ATNR persistence, and significant reading and spelling difficulties. The findings suggest that persistence of an early sub-cortical reflex system may be associated with some of the motor and cognitive difficulties experienced by children with partial hearing.

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This paper introduces the paired comparison model as a suitable approach for the analysis of partially ranked data. For example, the Inglehart index, collected in international social surveys to examine shifts in post-materialistic values, generates such data on a set of attitude items. However, current analysis methods have failed to account for the complex shifts in individual item values, or to incorporate subject covariates. The paired comparison model is thus developed to allow for covariate subject effects at the individual level, and a reparameterization allows the inclusion of smooth non-linear effects of continuous covariates. The Inglehart index collected in the 1993 International Social Science Programme survey is analysed, and complex non-linear changes of item values with age, level of education and religion are identified. The model proposed provides a powerful tool for social scientists.

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We compare the achievable performance of adaptive beamforming (A-BF) and adaptive orthogonal space time block coding (A-OSTBC) with outdated channel feedback. We extend our single user setup to multiuser diversity systems employing adaptive modulation, and illustrate the impact of feedback delay on the multiuser diversity gain with either A-OSTBC or A-BF. Using closed-form expressions for spectral efficiency and average BER of a multiuser diversity system derived in this paper, we prove that the A-BF scheme outperforms the A-OSTBC scheme with no feedback delay. However, when the feedback delay is large, the A-OSTBC scheme achieves better performance due to the reduced diversity advantage of A-BF. We observe that more transmit antennas bring higher spectral efficiency for BF. With small feedback delay, this becomes inverted using OSTBC, due to the effect of channel-hardening. Interestingly, however, we show that A-OSTBC with multiple users enjoys improved spectral efficiency when the number of transmit antennas is increased and the feedback delay is significant

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Inhibition of the PI3K (phosphoinositide 3-kinase)/Akt/mTORC1 (mammalian target of rapamycin complex 1) and Ras/MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase]/ERK pathways for cancer therapy has been pursued for over a decade with limited success. Emerging data have indicated that only discrete subsets of cancer patients have favourable responses to these inhibitors. This is due to genetic mutations that confer drug insensitivity and compensatory mechanisms. Therefore understanding of the feedback mechanisms that occur with respect to specific genetic mutations may aid identification of novel biomarkers that predict patient response. In the present paper, we show that feedback between the PI3K/Akt/mTORC1 and Ras/MEK/ERK pathways is cell-line-specific and highly dependent on the activating mutation of K-Ras or overexpression c-Met. We found that cell lines exhibited differential signalling and apoptotic responses to PD184352, a specific MEK inhibitor, and PI103, a second-generation class I PI3K inhibitor. We reveal that feedback from the PI3K/Akt/mTORC1 to the Ras/MEK/ERK pathway is present in cancer cells harbouring either K-Ras activating mutations or amplification of c-Met but not the wild-type counterparts. Moreover, we demonstrate that inhibition of protein phosphatase activity by OA (okadaic acid) restored PI103-mediated feedback in wild-type cells. Together, our results demonstrate a novel mechanism for feedback between the PI3K/Akt/mTORC1 and the Ras/MEK/ERK pathways that only occurs in K-Ras mutant and c-Met amplified cells but not the isogenic wild-type cells through a mechanism that may involve inhibition of a specific endogenous phosphatase(s) activity. We conclude that monitoring K-Ras and c-Met status are important biomarkers for determining the efficacy of PI103 and other PI3K/Akt inhibitors in cancer therapy.

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A continuous cell-line has been shown to be adaptable to preparation of supernatants containing lymphokine activities. Separation and partial purification of migration inhibiting, colony stimulating and interferon activities from such preparations has been achieved by the use of density gradient iso-electric focusing.

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The localisation and distribution of the cytoskeletal protein tubulin in the adult liver fluke Fasciola hepatica have been determined by an indirect immunofluorescence technique using a monoclonal antibody raised against beta-tubulin. Tubulin was demonstrated in the tegumental syncytium and in the tegumental cell bodies and their cytoplasmic connections with the surface syncytium. Immunostaining was also evident in the nerve fibres innervating sensory receptors in the tegument, in the nerve plexus innervating the sub-tegumental musculature and in the cytoplasmic extensions of the nurse cells within the vitelline follicle. Immunoblotting of whole fluke fractions produced a single band corresponding to a molecule of approximately 54 kDa in size. This figure corresponds with previous data obtained on tubulin from other helminth and eukaryotic sources.

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The joint fluids of 37 patients with rheumatoid arthritis, eight patients with traumatic injuries to their joints, two patients with Reiter's syndrome and three patients with psoriatic arthritis were tested for the presence of B cell colony stimulating activity (B cell CSA). B cell CSA was found in all of the joint fluids from the patients with rheumatoid arthritis but in none of the joint fluids from patients with traumatic injuries to their joints or in the joint fluids from the patients with Reiter's syndrome. A trace of B cell CSA was found in the joint fluid of one of the three patients with psoriatic arthritis. There was a positive correlation (r = 0.796) between the amount of rheumatoid factor present in the joint fluids and the titre of B cell CSA. This correlation was highly significant (P less than 0.001). The B cell CSA was localized to component(s) with molecular weight ranges 115-129 kD and 64-72 kD and an isoelectric point of 6.8. Its activity was sensitive to reduction with 2-mercaptoethanol and to the oxidising action of potassium periodate.