Liquid Immiscibility in the System Na2O-ZnO-B2O3-SiO2

The limits of miscibility within a portion of the system Na₂O-ZnO-B₂O₃-SiO₂ were determined at 650°, 800°, and 950°C. The miscibility gap at 800° and 950°C is a low dome, adjoining the zinc borosilicate miscibility gap. Below 755°C the dome intersects the Na2O-B₂O₃-SiO₂ face of the phase diagram. The locus of this intersection is in agreement with literature data on the sodium borosilicate system. Estimated tie-line placement in the ZnO-B₂O₃-SiO₂ miscibility gap at 1300°C resembles those reported for the corresponding CaO and SrO systems. The microscopic morphology of glasses with the weight composition xNa₂O-18ZnO-18B₂O₃-64SiO₂ with 0≤×≤12 is described in detail.     

Identification of faces obscured by noise: comparison of an artificial neural network with human observers

Face identification is easily accomplished by humans but is an exceptionally difficult task for machine vision algorithms. This report is the first to directly compare the face identification performance of humans with that of an artificialneural network,Dystal, using digitized images of the faces of eight individuals in an eight-alternative forced-response paradigm. The test images differed from the training images in facial expression, head tilt and rotation, amount and correlation of added noise, and the presence of a stocking mask in some of the images. The images were deliberately not preprocessed by a feature extraction algorithm to avoid confoundingthe performance of Dystal with the performance of the feature extraction algorithm.While human observers outperform Dystal at low noise levels, at high levels of correlated noise Dystal outperforms human observers, who score just above the chance level. The greater sensitivity to noise exhibited by human observers is attributed to the local feature extraction performed by human observers, but not by Dystal.     

A theory of cross-validation error

Abstract

This paper presents a theory of error in cross-validation testing of algorithms for predicting real-valued attributes. The theory justifies the claim that predicting real-valued attributes requires balancing the conflicting demands of simplicity and accuracy. Furthermore, the theory indicates precisely how these conflicting demands must be balanced, in order to minimize cross-validation error. A general theory is presented, then it is developed in detail for linear regression and instance-based learning     

Fault detection in linear discrete dynamic systems by a reduced order generalized-likelihood-ratio method

The detectability by conventional step-hypothesized generalized-likelihood-ratio (SHGLR) method for detection of a parameter change (fault detection) in a linear discrete dynamic system is analysed and it is shown that a weakly-diagnosable-space (WDS) exists for dynamics and sensor faults. Based on the fault detectability, a reduced order SHGLR method is then developed which highly improves the detection rate and speed. In the same framework of the GLR method, another reduced order detection scheme is given, which makes the most use of the information about the input and the state of the system to raise the detectability for faults for the case where the step hypothesis cannot be applied effectively.     

Module compiler for high-radix CCD-PLAs

A compiler has been developed that translates a multiple-valued logic expression into a circuit which realizes that expression. The circuits produced are for the high-radix peristaltic charge-coupled device (P2CCD) technology described by us in 1986. Each design is a programmable logic array (PLA), including the required sense amplifiers, dummy registers, voltage-to-charge converters, and precharge transistors. The multiple-valued expression is represented as a sum-of-products of literal operations, where product is the minimum operation and sum is the truncated sum operation. An example of a PLA implementation produced by the compiler is given.     

Ability of lactic acid bacteria to produce N-heterocycles causing mousy off-flavour in wine

Thirty‐four strains of the genera and species representative of the wine lactic acid bacteria (LAB) were screened in an ethanolic grape juice medium for the production of mousy off‐flavour as determined by an alkaline test strip sensory method. Most Lactobacillus spp., Oenococcus oeni and Leuconostoc mesenteroides produced mousy off‐flavour, whereas Pediococcus spp. were generally incapable of detectable off‐flavour formation. To verify these results, selected LAB were tested for the ability to produce the three sensorially potent N‐heterocycles, 2‐ethyltetrahydropyridine (ETPY), 2‐acetyltetrahydropyridine (ACTPY) and 2‐acetyl‐1‐pyrroline (ACPY), which are associated with the mousy off‐flavour in wine. N‐heterocycle formation was determined by incubating a high density of bacterial cells in a chemically defined N‐heterocycle assay medium, and quantifying the ‘mousy’ compounds by gas chromatography‐mass spectrometry. Most strains produced each of the three N‐heterocycles, with the general order for this capability being Lactobacillus (heterofermentative) > Oenococcus > Pediococcus. Strains of Lactobacillus hilgardii and Lactobacillus brevis were characterised as producing the highest concentration of ACTPY (328–580 μg/L, sensory threshold in water =1.6 μg/L), whereas ACPY and ETPY were produced at a moderate concentration (< 50 and < 10 μg/L, respectively). In addition to the formation of ACPY and ACTPY, three of five strains of the commercially important wine malolactic bacterium, O. oeni, produced the highest concentration of ETPY (87–162 μg/L). Strains of the homofermentative LAB, Pediococcus sp. and Lactobacillus plantarum L11a, however, produced only a relatively low concentration of each mousy N‐heterocycle (≤ 37 μg/L), suggesting that the ability of LAB to produce mousy N‐heterocycles is linked to the pathway of sugar catabolism. The importance of selecting LAB for induction of malolactic fermentation which have limited ability to produce mousy N‐heterocycles is emphasised.     

A non-linear programming approach to the computer-aided design of regulators using a linear-quadratic formulation†

A design technique is proposed for linear regulators in which a feedback controller of fixed structure is chosen to minimize an integral quadratic objective function subject to the satisfaction of integral quadratic constraint functions. Application of a non-linear programming algorithm to this mathematically tractable formulation results in an efficient and useful computer-aided design tool. Particular attention is paid to computational efficiency and various recommendations are made. Two design examples illustrate the flexibility of the approach and highlight the special insight afforded to the designer.     

Wine bottle closures: physical characteristics and effect on composition and sensory properties of a Semillon wine 1. Performance up to 20 months post-bottling

A Semillon wine was bottled using 14 different closures: a screw‐cap type, two grades of conventional natural cork, two ‘technical cork’ closures (natural cork with a synthetic component), and 9 closures manufactured from synthetic polymer material. Closure performance was evaluated for physical aspects (e.g. extraction force and energy, change in closure diameter, and ease of closure reinsertion), and for wine composition and sensory properties. Wine under the screw cap closure retained the greatest concentration of sulfur dioxide (SO₂) and ascorbic acid and had the slowest rate of browning. For other closures the trend of SO₂ loss relative to the screw cap closure was apparent from an early stage of testing, and was most evident in the group of synthetic closures, intermediate in the conventional corks, and least evident in the technical cork closures. The loss of SO₂ was in general highly correlated with an increase in wine browning (OD₄₂₀) and the concentration of SO₂ in the wine at six months was a strong predictor of future browning in the wine, particularly after eighteen months. Neither the concentration of dissolved oxygen at bottling (0.6–3.1 mg/L), nor the physical closure measures were predictors of future browning. For several closures upright storage tended to accelerate loss of SO₂ from the wine, but in many cases this effect was marginal. The closures differed widely in regard to physical characteristics, and in general synthetic corks appeared least ‘consumer‐friendly’ in terms of extraction forces, energies, and ease of closure re‐insertion, but there was a trend for natural cork closures to exhibit larger variability in physical characteristics than technical cork and synthetic closures. Sensory analysis indicated large differences in wine flavour properties, with closures which tended to result in the best retention of free SO₂ having wine sensory scores for ‘citrus’ that were generally high whilst scores for the attributes ‘developed’/‘oxidised’ were low. The situation was reversed for wine under closures that performed poorly in the retention of free SO₂. It was found that below a critical level of free SO₂ remaining in the wine, closures exhibited substantially higher ‘oxidised’ aroma. Whilst trichloroanisole‐type (TCA) taint was a noticeable problem for some cork and technical cork closures, any plastic‐type taint appeared not to be a problem with most synthetic closures.