Aeroservoelastic modeling and applications using minimum-state approximations of the unsteady aerodynamics

Various control analysis, design, and simulation techniques for aeroelastic applications require the equations of motion to be cast in a linear time-invariant state-space form. Unsteady aerodynamics forces have to be approximated as rational functions of the Laplace variable in order to put them in this framework. For the minimum-state method, the number of denominator roots in the rational approximation. Results are shown of applying various approximation enhancements (including optimization, frequency dependent weighting of the tabular data, and constraint selection) with the minimum-state formulation to the active flexible wing wind-tunnel model. The results demonstrate that good models can be developed which have an order of magnitude fewer augmenting aerodynamic equations more than traditional approaches. This reduction facilitates the design of lower order control systems, analysis of control system performance, and near real-time simulation of aeroservoelastic phenomena

Some programming techniques for increasing program versatility and efficiency on CDC equipment

Five programming techniques used to decrease core and increase program versatility and efficiency are explained. The techniques are: (1) dynamic storage allocation, (2) automatic core-sizing and core-resizing, (3) matrix partitioning, (4) free field alphanumeric reads, and (5) incorporation of a data complex. The advantages of these techniques and the basic methods for employing them are explained and illustrated. Several actual program applications which utilize these techniques are described as examples

Units of Evidence for Analyzing Subdisciplinary Difference in Data Practice Studies

Digital libraries (DLs) are adapting to accommodate research data and related services. The complexities of this new content spans the elements of DL development, and there are questions concerning data selection, service development, and how best to align these with local, institutional initiatives for cyberinfrastructure, data-intensive research, and data stewardship. Small science disciplines are of particular relevance due to the prevalence of this mode of research in the academy, and the anticipated magnitude of data production. To support data acquisition into DLs – and subsequent data reuse – there is a need for new knowledge on the range and complexities inherent in practice-data-curation arrangements for small science research. We present a flexible methodological approach crafted to generate data units to analyze these relationships and facilitate crossdisciplinary comparisons.Library Services (LG-06-07-0032-07) and National Science Foundation (OCI-0830976).is peer reviewe

Design of a candidate flutter suppression control law for DAST ARW-2

A control law is developed to suppress symmetric flutter for a mathematical model of an aeroelastic research vehicle. An implementable control law is attained by including modified LQC (Linear Quadratic Gaussian) design techniques, controller order reduction, and gain scheduling. An alternate (complementary) design approach is illustrated for one flight condition wherein nongradient-based constrained optimization techniques are applied to maximize controller robustness

Fitting aerodynamic forces in the Laplace domain: An application of a nonlinear nongradient technique to multilevel constrained optimization

A technique which employs both linear and nonlinear methods in a multilevel optimization structure to best approximate generalized unsteady aerodynamic forces for arbitrary motion is described. Optimum selection of free parameters is made in a rational function approximation of the aerodynamic forces in the Laplace domain such that a best fit is obtained, in a least squares sense, to tabular data for purely oscillatory motion. The multilevel structure and the corresponding formulation of the objective models are presented which separate the reduction of the fit error into linear and nonlinear problems, thus enabling the use of linear methods where practical. Certain equality and inequality constraints that may be imposed are identified; a brief description of the nongradient, nonlinear optimizer which is used is given; and results which illustrate application of the method are presented

Control law design to meet constraints using SYNPAC-synthesis package for active controls

Major features of SYNPAC (Synthesis Package for Active Controls) are described. SYNPAC employs constrained optimization techniques which allow explicit inclusion of design criteria (constraints) in the control law design process. Interrelationships are indicated between this constrained optimization approach, classical and linear quadratic Gaussian design techniques. Results are presented that were obtained by applying SYNPAC to the design of a combined stability augmentation/gust load alleviation control law for the DAST ARW-2

Application of optimization techniques to the design of a flutter suppression control law for the DAST ARW-2

The design of a candidate flutter suppression (FS) control law for the symmetric degrees of freedom for the DAST ARW-2 aircraft is discussed. The results illustrate the application of several currently employed control law design techniques. Subsequent designs, obtained as the mathematical model of the ARW-2 is updated, are expected to employ similar methods and to provide a control law whose performance will be flight tested. This study represents one of the steps necessary to provide an assessment of the validity of applying current control law synthesis and analysis techniques in the design of actively controlled aircraft. Mathematical models employed in the control law design and evaluation phases are described. The control problem is specified by presenting the flutter boundary predicted for the uncontrolled aircraft and by defining objectives and constraints that the controller should satisfy. A full-order controller is obtained by using Linear Quadratic Gaussian (LQG) techniques. The process of obtaining an implementable reduced-order controller is described. One example is also shown in which constrained optimization techniques are utilized to explicitly include robustness criteria within the design algorithm

Tools for active control system design

Efficient control law analysis and design tools which properly account for the interaction of flexible structures, unsteady aerodynamics and active controls are developed. Development, application, validation and documentation of efficient multidisciplinary computer programs for analysis and design of active control laws are also discussed

Introduced Fungi: Some Cause Significant Plant Disease Problems

Species of the three groups of fungi characterized here on the basis of their energy source acquisition have differing potentials for becoming problem organisms following introduction as alien fungi new to Iowa. The decomposer group of fungi that obtain an energy supply by action of extracellular enzyme activity on dead plant tissues typically have perennial mycelium, are cosmopolitan in distribution, and are unlikely to become problems even if established. The second group, the mycorrhizal/lichen group are highly specific in their relationships. The mycorrhizal fungus group have a potential for being introduced as mycorrhiza already established with the roots of particular vascular plants. Their potential for survival and establishment would be linked with that of their vascular plant associate. The third large and diverse group of plant parasitic fungi holds great potential for becoming destructive problem fungi on susceptible native plant species. In Iowa, the development of the white pine blister rust fungus Cronartium ribicola Fischer on Pinus strobus L. and Ophiostoma ulmae (Buisman) Nannf. and Ophiostoma nrwo-ulmae Brasier on elms, particularly on Ulmus americana L., are classic examples of the destruction of native plant species by introduced fungi

Professional Development Based On The Common European Framework of Reference for Languages And The New Ontario French Immersion Curriculum: A Case Study of Reflective Practice

In this multi-phase case study, the teacher researcher aimed to determine how teachers can be assisted in implementing some principles of the Common European Framework of Reference for Languages/CEFR (Council of Europe, 2001) into their pedagogical practices for primary-aged children enrolled in early French Immersion programs. Through a series of interviews conducted over three phases and a five-month period, the researcher led the teacher participant through professional development (PD) to shed light on the PD needed for French Immersion and other FSL teachers to adopt key principles of CEFR-inspired pedagogy into their practice. The results suggest that PD should be offered at the board or provincial level for teachers to understand and be able to implement these pedagogical principles. Moreover, assigning early childhood educators who do not know French to work alongside full-day kindergarten French Immersion teachers impedes the ability of those immersion teachers who are familiar with principles of CEFR-inspired teaching to implement them. The results of this empirical study expand on previous research conducted on the feasibility of introducing the CEFR into Canadian FSL pedagogy. This ground-breaking research explores how educators grapple with a pedagogical innovation and the challenges they face when trying to implement it to meet their own and ministry goals