Improving the nonlinear models characteristics of dynamical systems

The qualitative characteristics of the models are studied: the degree of observability, controllability and parametric identity. The numerical criteria of linear models qualitative characteristics of one class in the SDC representation are used to determine such characteristics. Usage methods of the models with improved characteristics in the aircraft navigation system of the aircraft are described. Keywords aircraft; navigation complex; adaptive non-linear Kalman filter; method of arguments group accounting; nonlinear control algorithm; SDC representation; observability degree criterion; controllability degree criterion; parametric identity degree criterion

Methods for determining the qualitative character¬istics of dynamic systems models

The assessment criteria of observability, controllability, parametric identifiability for linear stationary and non-stationary systems, as well as for non-linear systems, are introduced. Some known approaches to solving problems of determining the degree of observability, controllability, parametric identifiability and adaptability of linear and nonlinear models of dynamical systems are considered. Keywords model of a dynamic object; structural properties; quality characteristics; degree of controllability; degree of observability; degree of parametric identifiability; degree of adaptability

Modification of the federated Kalman filter in the correction scheme of the navi¬gation systems for aircraft carrier aircraft

The scheme of the navigation information correction of the aircraft when making take-off and landing maneuvers on a moving aircraft carrier is considered. As an algorithm for estimating navigation information, is proposed to use a federated Kalman filter and a special procedure to speed up the process of obtaining reliable estimates of the errors of navigation systems. The developed modification operability of the Kalman filter is con¬firmed by the results of mathematical modeling. Keywords: aircraft carrier aircraft; taking off and landing on an aircraft carrier; navigation system; cor¬rection; Kalman federated filter; degree of observability.

Engineering the emergence of norms: a review

Complex systems often exhibit emergent behaviour, unexpected macro-level behaviour caused by the interaction of micro-level components. In multiagent systems, these micro-level components may be autonomous agents and the emergent behaviour may be expressed as norms—patterns of behaviour that arise among the agents in response to their environment and each other. These emergent norms may be beneficial (e.g. by encouraging cooperative behaviour), or detrimental, but in either case it is useful to recognize these norms as they emerge and either encourage or discourage their establishment. We term this process engineering the emergence of norms and have identified three steps: the identification of a possible norm, evaluation of its benefit and its encouragement (or discouragement). This paper is an attempt to provide a survey of existing research related to these steps. We also provide an analysis of the approaches based upon their suitability for a variety of normative systems: we examine the requirements for agents to have autonomy over their choice of norms, the degree of observability required in the system, and the norm enforcement methods. The paper concludes with an discussion of open issues.

On the Observability of Oceanic Gyres

This study examines the observability of a stratified ocean in a square flat basin on a midlatitude beta plane. Here, “observability” means the ability to establish, in a finite interval of time, the time-dependent ocean state given density observations over the same interval and with no regard for errors. The dynamics is linearized and hydrostatic, so that the motion can be decomposed into normal modes and the observability analysis is simplified. An observability Gramian (a symmetric matrix) is determined for the flows in an inviscid interior, in frictional boundary layers, and in a closed basin. Its properties are used to establish the condition for complete observability and to identify optimal data locations for each of these flows. It is found that complete observability of an oceanic interior in time-dependent Sverdrup balance requires that the observations originate from the westernmost location at each considered latitude. The degree of observability increases westward due to westward propagation of long baroclinic Rossby waves: data collected in the west are more informative than data collected in the east. Likewise, the best locations for observing variability in the western (eastern) boundary layer are near (far from) the boundary. The observability of a closed basin is influenced by the westward propagation and the boundaries. Optimal data locations that are identified for different resolutions (0.01 to 1 yr) and lengths of data records (0.2 to 20 yr) show a variable influence of the planetary vorticity gradient. Data collected near the meridional boundaries appear always less informative, from the viewpoint of basin observability, than data collected away from these boundaries.

A Novel Degree of Observability Used for Measurement Selections in Gas Path Diagnostics

A novel method for measurement selections of gas path diagnostics has been developed. This method is based on the singular value decomposition of the observability matrix of linear systems, which are a good approximation of the nonlinear ones for small deviations. It also employs the concept of the degree of observability to formulate the criteria. The states with high degree of observability and the measurement sets with high overall degree of observability result in high estimation accuracy in gas path diagnostics. A heavy-duty gas turbine model is used to validate this method. The influence of the gas turbine nonlinearity, the measurement noise, and the overdetermined measurement on degree of observability is analyzed. The overall degree of observability is calculated for different measurement sets of heavy-duty gas turbine. The gas path diagnostics simulations with different measurement sets using the weighted least-squares estimation method and the extended Kalman filter are conducted. The quality of gas path diagnostics simulation with different measurement sets is assessed and the results demonstrate the capability of the developed method for measurement selections in gas path diagnostics.