Combined Filtering and Parameter Estimation for Discrete-Time Systems Driven by Approximately White Gaussian Noise Disturbances

In the problem of combined filtering and parameter estimation one considers a stochastic dynamical system whose state x_t is only partially observed through an observation process y_t. The stochastic model for the process pair (x_t, y_t) depends furthermore on an unknown parameter theta. Given an observation history of the process y_t, the problem then consists in estimating recursively both the current state x_t of the system (filtering) as well as the value theta of the parameter (Bayesian parameter estimation). The problem is a rather difficult one: Even if, conditionally on a given value of theta, the process pair (x_t, y_t) satisfies a linear-Gaussian model so that the filtering problem for x_t can be solved via the familiar Kalman-Bucy filter; when theta is unknown, the problem becomes a difficult nonlinear filtering problem. The present paper, partly based on previous joint work of one of the authors, makes a contribution towards the solution of this problem in the case of discrete time and of a (conditionally on theta) linear model for x_t, y_t. The solution that is obtained is shown to be robust with respect to small variations in the a priori distributions in the model, in particular those of the disturbances

Phenotypic analysis of milk coagulation properties and mineral content of Pinzgauer cattle breed

Abstract. This study aimed to characterize milk coagulation properties (rennet coagulation time, curd-firming time and curd firmness 30min after rennet addition to milk) and major mineral contents (Ca, Mg, P, K and Na) in Pinzgauer dual-purpose cattle breed. The edited dataset consisted of 7763 milk observations from 851 cows reared in 60 herds in the Alpine area of Bolzano province (Italy). Data were analysed through a linear mixed model which included stage of lactation, parity and their interaction as fixed effects, and cow and herd test date as random effects. Rennet coagulation time, curd-firming time and curd firmness 30min after rennet addition to milk averaged 22.66min, 5.53min and 16.79mm, respectively. The most abundant minerals were P (1495mgkg−1) and Ca (1344mgkg−1), and the least abundant Mg (141mgkg−1). Compared to their older contemporaries, early-lactating younger animals yielded milk that was more favourable for cheese production (i.e. with shorter coagulation time and stronger curd firmness). Mineral contents were lower in milk of primiparous than multiparous cows, except for Na. Moreover, Ca, Mg, P and Na contents decreased from parturition to peak of lactation and increased thereafter, except for K, which exhibited an opposite trend. Our results showed that Pinzgauer breed produced milk with better coagulation properties and mineral content, from a technological point of view, in first than later parities and in early than late lactation. The characterization of milk coagulation properties and mineral content in autochthonous breeds is important to increase their value and marketability of their products.</p

Noise, age and gender effects on speech intelligibility and sentence comprehension for 11- to 13-year-old children in real classrooms.

The present study aimed to investigate the effects of type of noise, age, and gender on children\u2019s speech intelligibility (SI) and sentence comprehension (SC). The experiment was conducted with 171 children between 11 and 13 years old in ecologically-valid conditions (collective presentation in real, reverberating classrooms). Two standardized tests were used to assess SI and SC. The two tasks were presented in three listening conditions: quiet; traffic noise; and classroom noise (non-intelligible noise with the same spectrum and temporal envelope of speech, plus typical classroom sound events). Both task performance accuracy and listening effort were considered in the analyses, the latter tracked by recording the response time (RT) using a single-task paradigm. Classroom noise was found to have the worst effect on both tasks (worsening task performance accuracy and slowing RTs), due to its spectro-temporal characteristics. A developmental effect was seen in the range of ages (11\u201313 years), which depended on the task and listening condition. Gender effects were also seen in both tasks, girls being more accurate and quicker to respond in most listening conditions. A significant interaction emerged between type of noise, age and task, indicating that classroom noise had a greater impact on RTs for SI than for SC. Overall, these results indicate that, for 11- to 13-year-old children, performance in SI and SC tasks is influenced by aspects relating to both the sound environment and the listener (age, gender). The presence of significant interactions between these factors and the type of task suggests that the acoustic conditions that guarantee optimal SI might not be equally adequate for SC. Our findings have implications for the development of standard requirements for the acoustic design of classrooms