Investigation of nonlinear motion simulator washout schemes

An overview is presented of some of the promising washout schemes which have been devised. The four schemes presented fall into two basic configurations; crossfeed and crossproduct. Various nonlinear modifications further differentiate the four schemes. One nonlinear scheme is discussed in detail. This washout scheme takes advantage of subliminal motions to speed up simulator cab centering. It exploits so-called perceptual indifference thresholds to center the simulator cab at a faster rate whenever the input to the simulator is below the perceptual indifference level. The effect is to reduce the angular and translational simulation motion by comparison with that for the linear washout case. Finally, the conclusions and implications for further research in the area of nonlinear washout filters are presented

Practical optimal flight control system design for helicopter aircraft. Volume 2: Software user's guide

A method by which modern and classical control theory techniques may be integrated in a synergistic fashion and used in the design of practical flight control systems is presented. A general procedure is developed, and several illustrative examples are included. Emphasis is placed not only on the synthesis of the design, but on the assessment of the results as well. The first step is to establish the differences, distinguishing characteristics and connections between the modern and classical control theory approaches. Ultimately, this uncovers a relationship between bandwidth goals familiar in classical control and cost function weights in the equivalent optimal system. In order to obtain a practical optimal solution, it is also necessary to formulate the problem very carefully, and each choice of state, measurement and output variable must be judiciously considered. Once design goals are established and problem formulation completed, the control system is synthesized in a straightforward manner. Three steps are involved: filter-observer solution, regulator solution, and the combination of those two into the controller. Assessment of the controller permits and examination and expansion of the synthesis results

Universal schema for entity type prediction

Categorizing entities by their types is useful in many applications, including knowledge base construction, relation extraction and query intent prediction. Fine-grained entity type ontologies are especially valuable, but typically difficult to design because of unavoidable quandaries about level of detail and boundary cases. Automatically classifying entities by type is challenging as well, usually involving hand-labeling data and training a supervised predictor. This paper presents a universal schema approach to fine-grained entity type prediction. The set of types is taken as the union of textual surface patterns (e.g. appositives) and pre-defined types from available databases (e.g. Freebase) - yielding not tens or hundreds of types, but more than ten thousands of entity types, such as financier, criminologist, and musical trio. We robustly learn mutual implication among this large union by learning latent vector embeddings from probabilistic matrix factorization, thus avoiding the need for hand-labeled data. Experimental results demonstrate more than 30% reduction in error versus a traditional classification approach on predicting fine-grained entities types. © 2013 ACM

Identification of prodromal presentations of Parkinson's disease among primary care outpatients in Germany

Background: This study aimed to identify clinical features that predate the diagnosis of PD in a primary care setting. Methods: This retrospective case-control study was based on data from the Disease Analyzer database (IQVIA) and included 17,702 patients with Parkinson's disease and 17,702 non-PD controls matched for age, sex, and index year. We analyzed the prevalence of 15 defined diagnoses and symptoms documented within 2 years, ≥2 to <5, and ≥5 to <10 years prior to the index date in patients with and without PD. Logistic regression analyses were conducted to assess the association between PD and the predefined diagnoses. Results: The prevalence of motor, neuropsychiatric and autonomic features was higher in those with a later diagnosis of Parkinson's disease than controls for all three periods except for rigidity in the ≥2 to <5 and ≥5 to <10-year periods and erectile dysfunction in the most recent period before diagnosis. The clinical presentation recorded in the greatest percentage of patients was depression, followed by dizziness, insomnia, and constipation, but these were also common in the control population. The odds ratios were highest for increase in tremor, followed by balance impairment and memory problems, particularly in the latest period before diagnosis, and by constipation particularly in the earliest period examined. Conclusion: The prodromal features of PD could be identified in this large primary care database in Germany with similar results to those found in previous database studies despite differences in methodologies and systems

Towards designing robust coupled networks

Natural and technological interdependent systems have been shown to be highly vulnerable due to cascading failures and an abrupt collapse of global connectivity under initial failure. Mitigating the risk by partial disconnection endangers their functionality. Here we propose a systematic strategy of selecting a minimum number of autonomous nodes that guarantee a smooth transition in robustness. Our method which is based on betweenness is tested on various examples including the famous 2003 electrical blackout of Italy. We show that, with this strategy, the necessary number of autonomous nodes can be reduced by a factor of five compared to a random choice. We also find that the transition to abrupt collapse follows tricritical scaling characterized by a set of exponents which is independent on the protection strategy

Strange quark matter: mapping QCD lattice results to finite baryon density by a quasi-particle model

A quasi-particle model is presented which describes QCD lattice results for the 0, 2 and 4 quark-flavor equation of state. The results are mapped to finite baryo-chemical potentials. As an application of the model we make a prediction of deconfined matter with appropriate inclusion of strange quarks and consider pure quark stars.Comment: invited talk at Strangeness 2000, Berkeley; prepared version for the proceedings, 5 page