Eccentricity and hardness control in cold rolling mills with a dynamically constructed neural controller

The main objective of a steel strip rolling process is to produce high quality steel at a desired thickness.  Thickness reduction is the result of the speed difference between the incoming and the outgoing steel strip and the application of the large normal forces via the backup and the work rolls.  Gauge control of a cold rolled steel strip is achieved using the gaugemeter principle that works adequately for the input gauge changes and the strip hardness changes.  However, the compensation of some factors is problematic, for example, eccentricity of the backup rolls.  This cyclic eccentricity effect causes a gauge deviation, but more importantly, a signal is passed to the gap position control so to increase the eccentricity deviation.  Consequently, the required high product tolerances are severely limited by the presence of the roll eccentricity effects.
In this paper a direct model reference adaptive control (MRAC) scheme with dynamically constructed neural controller was used.  The aim here is to find the simplest controller structure capable of achieving an optimal performance.  The stability of the adaptive neural control scheme (i.e. the requirement of persistency of excitation and bounded learning rates) is addressed by using as the inputs to the reference model the plant's state variables.  In such a case, excitation is due to actual plant signals (states) affected by plant disturbances and noise.  In addition, a reference model in the form of a filter with a desired transfer function using Modulus Optimum design was used to ensure variance in the desired dynamic characteristics of the system.  The gradually decreasing learning rate employed by the neural controller in this paper is aimed at eliminating controller instability resulting from over-aggressive control.  The moving target problem (i.e. the difficulty of global neural networks to perfrom several separate computational tasks in closed -loop control) is addressed by the localized architecture of the controller.  The above control scheme and learning algorithm offers a method for automatic discovery of an efficient controller.
The resulting neural controller produces an excellent disturbance rejection in both cases of eccentricity and hardness disturbances, reducing the gauge deviation due to eccentricity disturbance from 33.36% to 4.57% on average, and the gauge deviation due to hardness disturbance from 12.59% to 2.08%.

Children's body image concerns and eating disturbance: a review of the literature

In recent years a large number of studies have examined body image concerns, and early symptoms of eating disturbance among children. However, to date there has been no synthesis or evaluation of these studies. The purpose of the present article is to review and evaluate the research that has examined body image concerns, and eating attitudes and behaviors among children 6 to 11 years of age. The instruments used to assess body image concerns and eating disturbance in children closely resemble those used with adolescents and adults. Overall, the psychometric data for these instruments are very good and there is sufficient evidence indicating that they can be used reliably and validly. In addition, similar variables to those studied in adolescent and adult samples have been found to be associated with children's body image concerns and early eating disturbance. These include gender, age, body mass index, race, sociocultural pressures, and self-concept. Our understanding of the development of body image concerns and eating disturbance in children is limited, however, by the fact that most of the research in this field has been based on cross-sectional data, and the studies have focused almost exclusively on weight-loss cognitions and behaviors.

Universal nonuniform random vector generator based on acceptance-rejection

The acceptance/rejection approach is widely used in universal nonuniform random number generators. Its key part is an accurate approximation of a given probability density from above by a hat function. This article uses a piecewise constant hat function, whose values are overestimates of the density on the elements of the partition of the domain. It uses a sawtooth overestimate of Lipschitz continuous densities, and then examines all local maximizers of such an overestimate. The method is applicable to multivariate multimodal distributions. It exhibits relatively short preprocessing time and fast generation of random variates from a very large class of distributions

Altered experience mediates the relationship between schizotypy and mood disturbance during shamanic-like journeying

Studies have found that shamanic practices are associated with statistically significant reductions in mood disturbance relative to baseline. However, contrary results were obtained for non-shamanic practitioners exposed to shamanic-like techniques. These inconsistent results may be partially due to a personality trait referred to as schizotypy, which has been demonstrated to influence susceptibility to shamanic-like techniques. Furthermore, given that an integral feature of shamanism is the production of altered states of awareness and altered experiences, and that shamanism is associated with health benefits, perhaps the production of such alterations affects health benefits. Consequently, the present study aimed to investigate whether altered state of awareness and altered experience mediated the association between schizotypy and mood disturbance during exposure to a shamanic-like condition. Sixty-nine non-shamans were randomly assigned to one of two conditions: shamanic-like journeying with drumming or sitting quietly with eyes open. Total mood disturbance-change was significantly negatively correlated with schizotypy and altered experience -- but not altered state of awareness -- and these correlations were significantly stronger for the shamanic-like journeying condition relative to the control condition. Furthermore, altered experience significantly mediated the association between schizotypy and total mood disturbance-change during exposure to shamanic-like journeying.

Disturbance decoupled observers for systems with unknown inputs

This note deals with the design of reduced-order disturbance decoupled scalar functional observers for linear systems with unknown inputs. Based on a parametric approach, existence conditions are derived and a design procedure for finding reduced-order scalar functional observers is given. The derived existence conditions are relaxed and the procedure can find first-order disturbance decoupled scalar functional observers for some cases where the number of unknown inputs is more than the number of outputs. Also, the observer matching condition, which is the necessary requirement for the design of state observers for linear systems with unknown inputs, is not required. Numerical examples are given to illustrate the attractiveness of the proposed design method.

A common disturbance decoupled observer for linear systems with unknown inputs

This paper presents a solution to the problem of designing a common linear functional observer that can observe a partial set of the state vector of two linear systems with unknown inputs. A new structure of a decoupled linear functional observer is proposed for systems subject unknown disturbances, using only the available output information. Existence conditions as well as a design procedure are given for constructing the proposed observer. A numerical example is given to illustrate the effectiveness of the new observer structure.

Impact of saltmarsh disturbance on seed quality of Sarcocornia (Sarcocornia quinqueflora), a food plant of an endangered Australian parrot

The article presents a study which evaluates the impact of saltmarsh perturbation on seed quality of Sarcocornia which is a food for the endangered Orange-bellied parrot in Australia. It notes the significant impact of grazing on the energy and availability of Sarcocornia seeds in saltmarshes and indicates that graze-free saltmarshes with regular inundation provide the highest potential for Sarcocornia seed availability. Further, the substantial factor of soil characteristics and salinity of flood water and inundation on the seed production of Sarcocornia is also discussed.

Host intra-clutch variation, cuckoo egg matching and egg rejection by great reed warblers

Prevailing theory predicts that lower levels of intra-clutch variation in host eggs facilitate the detection of brood parasitism. We assessed egg matching using both human vision and UV-VIS spectrophotometry and then followed the nest fate of great reed warblers naturally parasitised by European cuckoos. Rejection was predicted by the following three variables: matching between cuckoo and host eggs on the main chromatic variable defined by principal components analysis of the egg spectra (which has a strong loading in the UV); the number of host eggs in the nest; and human estimates of intra-clutch variation. The first variable is not correlated to human estimates of matching, which do not predict rejection. In line with another recent study, rejection rates were predicted by higher levels of intra-clutch variation in the host eggs, suggesting that higher rather than lower levels of intra-clutch variation can facilitate the discrimination of cuckoo eggs by hosts. We suggest that the importance of intra-clutch variation is context dependent, with intra-clutch variation being important when there is good matching between the host and the cuckoo eggs. Our results also suggest that both spectrometric and human visual assessments of egg matching and intra-clutch variation are prudent: the former provide the best method of estimating reflectance variation, whereas the latter include some assessment of patterns of maculation.