Optimal Hankel-norm approximation approach to model reduction of large-scale Markov chains

A model reduction problem of certain large-scale Markov chains under an optimal criterion for Hankel-norm approximation is discussed. The multi-dimensional Markov chain under investigation is assumed to have a finite-dimensional stationary state-transition matrix, which is first reformulated as a multi-input/multi-output (MIMO) linear time-invariant (LT1) stochastic system. Consequently, the resulting large-scale MIMO LTI stochastic system has a closed-form best approximant in the Hankel-norm from a specified class of stable lower-dimensional MIMO LTI systems.     

Design of reduced-order state estimators for linear time-varying multivariable systems

The design of reduced-order state estimators for linear time-varying multivariable systems is considered. Employing the concepts of matrix operators and the method of canonical transformations, this paper shows that there exists a reduced-order state estimator for linear time-varying systems that are ‘lexicography-fixedly observable’. In addition, the eigenvalues of the estimator can be arbitrarily assigned. A simple algorithm is proposed for the design of the state estimator.     

Subsolidus Compatibility in the System NaCl-KCl-AlCl3-NaF-KF-AlF3

The chemistry and properties of salts used as fluxes for recycling aluminum were studied. Many fluxing salts fall within the system NaCl-KCl-AlCl₃-NaF-KF-AlF₃, which has been shown to be a reciprocal system, with NaF-KCl, KC1-AIF₃, and NaCl-AIF₃ as the stable mixed-halide binaries. Twelve subsolidus compatibility tetrahedra were determined by X-ray analyses of samples heated in evacuated sealed tubes. X-ray measurements of quenched and annealed samples indicate that elpasolite, nominally K₂NaAlF₆, has a compositional range between 60 mo% Na₃AlF₆, 40 mol% K₃AlF₆ and 25 mol% Na₃AlF₆, 75 mol% K₃AIF₆. Improved X-ray powder data are given for KAIF₄, showing a previously reported structure to be essentially correct.     

INHIBITION OF LISTERIA INNOCUA AND L. MONOCYTOGENES IN A LABORATORY MEDIUM AND COLD-SMOKED SALMON CONTAINING LIQUID SMOKE

Five commercial liquid smokes were tested in vitro and the most inhibitory to Listeria monocytogenes ATCC 19115 and L. innocua ATCC 33090 was Charsol Supreme. Chum salmon samples (100-g each) were brined, dipped for 15 s at varying concentrations of liquid smoke, inoculated with L. innocua, cold-processed and analyzed. Liquid smoke concentrations of 60–100% reduced L. innocua by 3-log₁₀/g in the final product. Dwell times of 15 s to 5 min using 60% liquid smoke gradually decreased Listeria survival with an optimum 5-min dip. Isoeugenol was antilisterial in vitro but lacked synergism with liquid smoke in cold-smoked salmon. An immunoassay kit detected low inoculum levels (< 100 CFU/g) of L. innocua in one of three samples that were treated with liquid smoke for two and four minutes. Charsol Supreme was antilisterial but could not be relied on to totally eliminate Listeria in cold-smoked salmon. Panelists found the 0 to 2-min dipped sockeye salmon slightly desirable with no significant (p < 0.05) differences. The 5-min treatment was significantly (p < 0.05) darker, scored lower in desirability and flavor and contained 93 ppm of phenolic compounds.     

Tensor Product Production System: a Modular Architecture and Representation

Can connectionist networks effectively represent and process structure? A technique called ‘tensor product representations’, which formalizes and generalizes the approaches of several previous connectionist models, was developed by Smolensky and shown to possess a number of desirable general properties. This paper shows how the technique can be effectively used to design a specific symbol-processing task: the serial execution of simple production rules requiring pattern matching, variable binding and structure manipulation. This ‘Tensor Product Production System’ is applied to one of the classes of production rules in Touretzky and Hinton's Distributed Connectionist Production System, and a number of comparisons are made between the two approaches. The mathematical simplicity and analyzability of the tensor product scheme allows the straightforward design of a simpler, more principled, and in some ways more efficient system.     

Real-Time lethality Evaluation During the Flame Sterilization of Canned Foods

A pilot-scale flame sterilizer was interfaced to a microcomputer for real-time thermal process evaluation of individual cans. The computerized system used a photodetector system to synchronize data acquisition at predetermined monitoring sites. Infrared sensors were used to measure can temperatures. Also, a method to measure can surface temperature was developed for infrared sensor calibrations. Foil thermocouples were found to be the most accurate and reliable for surface temperature measurements. However, a thin gauge wire thermocouple attached to the inside of the can end surface was a more practical and economical method for sensor calibration.     

RHEOLOGICAL CHARACTERIZATION OF COMMERCIALLY PROCESSED FLUID MILKS

Flow profiles of commercially processed whole, two-percent, one-percent and nonfat milks with added solids as well as skim milk without added solids were measured using a rotational steady shear viscometer. Also tested were mixtures of concentrated skim milk added to skim milk over a range of 9.7% to 20.2% total solids. A shear rate range of 121 to 486 s^-1 was used with a cone and plate geometry. In all cases, linear plots of shear stress versus shear rate with small nonzero intercepts were obtained.     

PACKING TECHNOLOGY FOR FRESH AND MINIMALLY PROCESSED FRUITS AND VEGETABLES

Flexible plastic packaging in the fresh produce industry has functioned in the past to facilitate product handling and provide brand identification. Greater emphasis on freshness and product quality has resulted in a re-evaluation of plastic for fresh and minimally processed products. Polyvinylchloride, used primarily for overwrapping, and polyethylene, used for bags, have been the most popular films, but co-extrusion technology has provided a means of controlling gas transmission rates. Individual film wrapping represents a rediscovery of an old technique that has applications in prevention of shrinkage and altering of ripening patterns. Modified atmosphere packaging and value added products represent other new technologies that use packaging to extend shelf-life.