NEGATIVE AND POSITIVE EXPLANATIONS IN EXPERT SYSTEMS

A methodology for management of constraints in VLSI data bases is presented in this paper. The process of management is based on forma! mechanisms of attribute grammar theory. Examples of a modularized knowledge representation of a circuit at interconnection and logic levels based on attribute grammars illustrate the methodology. The ultimate goal and benefit of the proposed methodology is a well-defined development technique for VLSI design tools that will allow the user to generate a transformation system, a knowledge representation, and a system to manipulate this representation, all from a simple specification. In addition, context-dependent specifications at lower levels are automatically generated from the higher-level specifications.     

酵母多肽：一种真实有效的防脱生发成分

使用HAIRGENYL~?测定一组男性志愿者的头发生长,验证了产品的抗脱发作用。数据经志愿者自评问卷证实了成分的功效表现。结果表明HAIRGENYL~?可使头发更浓密更强韧,而且头皮更密集覆盖,防止秃发的形成。     

Design parameters of part-ordering devices Design parameters selection and ordering of part-orienting devices†

We study the design problem of part-orienting systems which are often employed in many manufacturing environments to orient parts for assembly or to perform operations. A part-orienting system is composed of a number of orienting devices. The problem of selecting proper design parameters for the devices and of serially ordering them to make up the system is addressed in this paper. The problem is illustrated through a real example. Heuristic algorithms have been developed and computer experiments have been performed to evaluate their relative performances.     

ELECTROMAGNETIC TRANSIENTS ON COMPENSATED LINES UNDER CORONA

ABSTRACT

The purpose of this paper is to present a digital computational method for the determination of the fast electromagnetic transients propagating on compensated overhead power lines, evoked by internal or external over voltages, as effected by corona discharges. The approach enables the consideration of series capacitor and shunt reactor compensation. The line model is based on time-domain solution using the Runge-Kutta-Verner numerical technique to solve a set of simultaneous differential equations, whose number depends on the assumed number of line sections, as derived from the line equivalent circuit. The increase of the location-dependent conductor effective radius due to corona is considered as one of variable sets, using an iterative solution procedure. To avoid the parasitic Gibbs-oscillations due to the finite number of line sections (which are superimposed on the actual solutions, a set of properly chosen damping resistors is added to the line model, yielding a frequency-dependent damping. The simulation of the corona discharge uses a model derived from an experimentally measurable voltage-charge hysteresis loop relationship of a line test length. As far the input voltage stimuli are concerned, so the model can consider any voltage-time function (step, ramp, double-exponential, sine waves...etc), or even be in the form of tabulated numerical data. The validity of the model is checked by comparing its results to corresponding measurements.     

SENSORY TEXTURE PROFILE, GRAIN PHYSICO-CHEMICAL CHARACTERISTICS AND INSTRUMENTAL MEASUREMENTS OF COOKED RICE

Three samples of raw-milled rice, and 4 differently parboiled rices were used to study and to relate sensory perception to instrumental measurements. Variance analysis showed that some physico-chemical characteristics indicated great differences among rice samples: thickness of cooked grain, length/width ratio, water uptake, elastic recovery, white core rate and amylose and protein contents. The most discerning sensory attributes were: elasticity, stickiness, pastiness, mealiness, length of grain, firmness, crunchiness, time in mouth, brittle texture and juiciness. The correlation circle of the principal component analysis (PCA) showed high correlation between some sensory characteristics and instrumental measurements. Melting texture, surface moistness, juiciness, were positively correlated with water uptake (r = 0.70, 0.61, 0.71). Granular texture, crunchiness, brittleness and mealiness were significantly affected by white core presence (r = 0.81, 0.74, 0.86, 0.83). Elasticity was dependent upon elastic recovery and firmness measured by the Viscoelastograph, but not linearly. Length of cooked grain was correlated with the length/width ratio of raw grain (r = 0.83). Pastiness, compactness, stickiness were slightly influenced by the thickness of raw grain (r = 0.81, 0.67, 0.72). To a weaker extent, the sensory firmness was associated with the firmness measured by extrusion force using an Ottawa cell (r = 0.58). PCA showed greatdifferences in texture between rices. Two of the parboiled rices were very elastic, another was firm, granular, crunchy and mealy. The remaining two, cooked longer, were moister and more melting. Among the 3 samples of raw-milled rices, differences in grain length feeling and melting-granular-brittle characteristics. were distinguished.     

The effects of butter characteristics on the growth of Listeria monocytogenes

The behaviour of Listeria monocytogenes was assessed after inoculation into butters made so that they exhibited a range of characteristics. Water droplet size and dispersion throughout the butter affected the ability of L. monocytogenes to grow, its rate of growth and the maximum population level achieved. Listeria monocytogenes was able to grow better in 'coarse' compared to 'fine' butter. Salt in the butter adversely affected growth of L. monocytogenes. However, slow growth was apparent at even higher levels (e.g. 2.1+%) of total salt. Growth of L. monocytogenes in butter at 8°C was comparable to that at 21°C.     

Free-transfer lines with unreliable assembly stations and small buffers

This paper describes the arrangement in series of assembly stations that are linked by storage places. The distribution of the stations and of the number of places in the stocks affects the efficiency of the assembly. The results of the continuous model show that grouping stations by two or three does not improve the effectiveness of the line when the number of places is limited. On the other hand, the discrete synchronous model proved that it is profitable to group stations when a low capacity of storage is experienced; these results have been confirmed using a simulation software which processes the components in a discrete manner.     

MECHANICAL PROPERTIES OF UNPRESSED SEMI-HARD CHEESES BY UNIAXIAL COMPRESSION

Different lots of Tilsit cheeses, which are characterized by their open structure caused by pressing under their own weight during manufacture, were subjected to uniaxial compression, a quasi-standard for the evaluation of mechanical properties of hard and semi-hard cheeses. Additionally, video films showing the behaviour of the specimens during compression were analysed. For standard Tilsit with a fat content of 35% in dry matter, the cheese mass proved to be highly anisotropic with respect to stress response and lateral expansion expressed as apparent Poisson number. Specimens cut perpendicular to the flat side of the cheese wheels, which had lentil-shaped eyes with their major axis parallel to the compression plates, showed significantly higher stresses and lower Poisson numbers than specimens sampled parallel to the flat side of the cheese wheels. Therefore, stress values calculated on the basis of actual specimen diameter were different from those calculated by assuming constant specimen's volume. However, for samples with a fat content of approx. 60% in dry matter no differences caused by compression direction were observed.     

CHALLENGE STUDIES WITH PROTEOLYTIC CLOSTRIDIUM BOTULINUM IN YEAST AND CHEMICALLY LEAVENED CRUMPETS PACKAGED UNDER MODIFIED ATMOSPHERES

Challenge studies were done with proteolytic Clostridium botulinum (10³ spores/g) in yeast-and chemical-leavened crumpets (50-g) packaged in air with an ethanol vapor (2-G Ethicap®) generator or in 100% CO₂ and stored at ambient temperature (25C) for 30 days. Neurotoxin was detected in all gas- (CO₂) packaged crumpets after 5 days regardless of the method of leavening. While neurotoxin was delayed for 10 days in chemical-leavened Ethicap®-packaged crumpets, it was not detected in any similarly packaged yeast-leavened crumpets throughout storage. This inhibition of growth and neurotoxin production by C. botulinum was attributed to the production of ethanol by Saccharomyces cerevisiae in the yeast leavened crumpets, in conjunction with the ethanol vapor generated by the Ethicap® sachets (2-G), to levels to inhibitory to the growth of C. botulinum (>2.8% v/v). Subsequent challenge studies in sterile crumpets inoculated with either C. botulinum (10³ spores/g) or a co-inoculum of C. botulinum (10³ spores/g) and S. cerevisiae (10⁵ CFU/g) confirmed the significant role (p<0.001) of S. cerevisiae in enhancing the antibotulinal efficacy of ethanol vapor. These studies showed that the method of crumpet leavening could have a profound effect on the growth of and neurotoxin production by C. botulinum in crumpets packaged under modified atmospheres.     

An evaluation of methods for inoculating Listeria monocytogenes into butter for microbiological experimentation

The behaviour of Listeria monocytogenes Scott A was assessed when inoculated into butter using six different methods. The butter was made using a laboratory-scale butter churn to give consistency in the butter ingredients. No increase in count was seen using the 'stab' or 'contact' methods of butter inoculation. No inoculation method was found to be ideal for every inoculation experiment that may be required. However, it was concluded that the 'mix' and 'bead' methods were most appropriate if the 'cream' inoculation method could not be used.