28,734 research outputs found
Alleviation of unbalanced rotor loads by single blade controllers
A novel approach to reducing the unbalance rotor loads by pitch control is presented in this paper. Each blade has its own actuator, sensors and controller. These localised blade control systems operate in isolation without need of communication with each other. This single blade control approach to regulation of unbalanced rotor loads has several advantages including being straightforward to design and easy to tune. Furthermore, it does not affect the operation of the central controller and the latter need not be re-designed when used in conjunction with the single blade controllers. Their performance is assessed using BLADED simulations
Technological learning for innovating towards sustainable cultivation practices: the Vietnamese smallholder rose sector
Deregulation and globalisation has altered the views of public involvement in development and led to strategies focusing on private sector participation. An implicit assumption seems to be that these linkages will enhance the technological capacity of smallholder producers by way of more cost-efficient technologies trickling down through the value chain or by quality requirements inducing best practices. The argument put forward in this paper is that sustainable non traditional agricultural chain development requires more purposeful actions and institutional transitions, both in the public and private spheres, targeting improved upstream innovative capacities. Empirical findings from a Dutch-Vietnamese partnership on sustainable floriculture development are used. Research revealed that the pest and disease control solutions applied by smallholder rose growers were incremental adaptations of experiences obtained in former food crop cultivation practices. Floriculture however may require more drastic changes in cultivation practices to make the sector more environmentally benign. In the case of smallholder Vietnamese flower producers, this implies adaptation of knowledge and skills currently not present. An important hindrance in promoting this knowledge and skills appears to be the weak vertical linkages between flower growers and public and private research and development organizations
Deep-Sea Archaea Fix and Share Nitrogen in Methane-Consuming Microbial Consortia
Nitrogen-fixing (diazotrophic) microorganisms regulate productivity in diverse ecosystems; however, the identities of diazotrophs are unknown in many oceanic environments. Using single-cell–resolution nanometer secondary ion mass spectrometry images of ^(15)N incorporation, we showed that deep-sea anaerobic methane-oxidizing archaea fix N_2, as well as structurally similar CN^–, and share the products with sulfate-reducing bacterial symbionts. These archaeal/bacterial consortia are already recognized as the major sink of methane in benthic ecosystems, and we now identify them as a source of bioavailable nitrogen as well. The archaea maintain their methane oxidation rates while fixing N_2 but reduce their growth, probably in compensation for the energetic burden of diazotrophy. This finding extends the demonstrated lower limits of respiratory energy capable of fueling N_2 fixation and reveals a link between the global carbon, nitrogen, and sulfur cycles
Identifying harmonic attributes from online partial discharge data
Partial discharge (PD) monitoring is a key method of tracking fault progression and degradation of insulation systems. Recent research discovered that the harmonic regime experienced by the plant also affects the PD pattern, questioning the conclusions about equipment health drawn from PD data. This paper presents the design and creation of an online system for harmonic circumstance monitoring of distribution cables, using only PD data. Based on machine learning techniques, the system can assess the prevalence of the 5th and 7th harmonic orders over the monitoring period. This information is key for asset managers to draw correct conclusions about the remaining life of polymeric cable insulation, and prevent overestimation of the degradation trend
The Canon Wars
Canons are taking their turn down the academic runway in ways that no one would have foretold just a decade ago. Affection for canons of construction has taken center stage in recent Supreme Court cases and in constitutional theory. Harvard Dean John Manning and originalists Will Baude and Stephen Sachs have all suggested that principles of “ordinary interpretation” including canons should inform constitutional interpretation. Given this newfound enthusiasm for canons, and their convergence in both constitutional and statutory law, it is not surprising that we now have two competing book-length treatments of the canons—one by Justice Scalia and Bryan Garner, Reading Law, and the other by Yale Law Professor William N. Eskridge, Interpreting Law. Both volumes purport to provide ways to use canons to read statutes and the Constitution. In this Review of Interpreting Law, we argue that this contemporary convergence on canons raises some significant interpretive questions about judicial power and the very idea of a canon
The Frames Behind the Games: Player's Perceptions of Prisoner's Dilemma, Chicken, Dictator, and Ultimatum Games
The tension between cooperative and competitive impulses is an eternal issue for every society. But how is this problem perceived by individual participants in the context of a behavioral games experiment? We first assess individual differences in players’ propensity to cooperate in a series of experimental games. We then use openended interviews with a subset of those players to investigate the various concepts (or ‘frames’) they used when thinking about self-interested and cooperative actions. More generally, we hope to raise awareness of player’s perceptions of experimental environments to inform both the design and interpretation of experiments and experimental data.Laboratory Experiment, Frames, Selfishness, Cooperation
On the Ground Validation of Online Diagnosis with Twitter and Medical Records
Social media has been considered as a data source for tracking disease.
However, most analyses are based on models that prioritize strong correlation
with population-level disease rates over determining whether or not specific
individual users are actually sick. Taking a different approach, we develop a
novel system for social-media based disease detection at the individual level
using a sample of professionally diagnosed individuals. Specifically, we
develop a system for making an accurate influenza diagnosis based on an
individual's publicly available Twitter data. We find that about half (17/35 =
48.57%) of the users in our sample that were sick explicitly discuss their
disease on Twitter. By developing a meta classifier that combines text
analysis, anomaly detection, and social network analysis, we are able to
diagnose an individual with greater than 99% accuracy even if she does not
discuss her health.Comment: Presented at of WWW2014. WWW'14 Companion, April 7-11, 2014, Seoul,
Kore
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