Showing papers by "City University London published in 1982"
TL;DR: The theory and background to a design study for an information retrieval (IR) system based on the attempt to represent the anomalous states of knowledge (ASKs) underlying information needs and the methods and results are discussed.
Abstract: In ‘ASK for Information Retrieval: Part I’, we discussed the theory and background to a design study for an information retrieval (IR) system based on the attempt to represent the anomalous states of knowledge (ASKs) underlying information needs. In Part II, we report the methods and results of the design study, and our conclusions.
367 citations
TL;DR: It is demonstrated, by partial example, that the information provision mechanism fulfills the requirements of this approach, and that this approach appears able to provide a means for analysis and design of information provision mechanisms which retains the level of complexity necessary for the sorts of mecha nisms the authors' assumptions imply.
Abstract: We discuss the functional analysis and design of a general information provision mechanism. Our basic assumptions are that information provision mechanisms are best considered as a part of a problem management system which includes user, mechanism and knowledge resource, that such mechanisms must necessarily be multi-functional, and that they will include both human and machine components. By analyzing how such a mechanism must operate in order to help the user to treat her/his problem, we identify a number of discrete functions which interact in complex ways. This leads us to discuss a particular approach to the modelling and design of problem treatment situations, distributed problem treatment. This ap proach assumes that problem treatment can be broken down into a number of separate entitites, each of which makes hypotheses about its particular area of responsibility, and com municates these results to the other entities of the mechanism. We demonstrate, by partial example, that the information provisi...
108 citations
TL;DR: Two experiment are reported which demonstrated intransitivity in category judgments, thus challenging a widely held assumption that the relation between categorized sets is one of class inclusion.
90 citations
TL;DR: The authors introduced new measures of the mean and variance of inflation and growth expectations, based on tendency survey data from four major European economies, and found that unpredictable disturbances typically have an internal rather than an international origin.
85 citations
TL;DR: The results suggest that even under a single motivational state the nature of signal-centered behavior can be determined by type of reinforcer, although water reinforcement produces less signal contact than food reinforcement, this can be facilitated with more severe water-deprivation levels, and high CS-contact rates using food reinforcement are not simply a product of reductions in body weight with food deprivation.
Abstract: In a series of three experiments, groups of food-deprived and water-deprived rats were given pairings of a retractable lever (CS(+)) with response-independent deliveries of either solid or liquid reinforcers. In Experiment 1 food-deprived rats given a solid-pellet reinforcer differentially tended to sniff, paw, mouth, and bite the CS(+) lever more often than a lever that was not paired with food (CS(-)), whereas food-deprived rats given a liquid reinforcer tended to differentially sniff, paw, and lick the CS(+) lever. 23(1/2)-hour water-deprived rats given liquid reinforcers showed very little CS(+) contact. In Experiment 2 increasing the severity of water deprivation from 23(1/2) to 47(1/2) hours significantly increased CS(+) contact. In Experiment 3, subjects that were simultaneously food and water deprived and given a water reinforcer failed to exhibit differential CS(+) contact, but subjects that were simultaneously food and water deprived and given a food reinforcer did acquire differential CS(+)-contact behavior. These results suggest that (a) even under a single motivational state the nature of signal-centered behavior can be determined by type of reinforcer, (b) although water reinforcement produces less signal contact than food reinforcement, this can be facilitated with more severe water-deprivation levels, and (c) high CS-contact rates using food reinforcement are not simply a product of reductions in body weight with food deprivation.
83 citations
54 citations
TL;DR: In this article, successive stages of the thermal decomposition of poly(vinylidene fluoride) during programmed heating, at low and high heating rates, in nitrogen, air and oxygen, were studied.
44 citations
42 citations
TL;DR: The results suggest that signal-centered behavior is not simply a manifestation of “conditioned hunger,” is determined to some extent by the animal's current need state, and is influenced by the status of specific reinforcer representations.
36 citations
TL;DR: In terpolymer (ABS) and antimony (III) oxide and chlorinated paraffin in high-density polyethylene (HDPE) have been measured and fitted by fourth-order polynomials.
35 citations
TL;DR: A statistical method is presented to assess and compare cardiac valve performances and to calculate the significance of the difference between two survival probabilities and the instantaneous rate of events and the median remaining lifetime.
TL;DR: In this article, the authors considered cavity flows driven by an applied horizontal temperature gradient in the high Rayleigh number limit for a fluid-saturated porous medium, and the analysis is concerned with the behaviour of the vertical boundary layer equations near the corners of the cavity.
Abstract: Cavity flows driven by an applied horizontal temperature gradient are considered in the high Rayleigh number limit for a fluid-saturated porous medium. The analysis is concerned with the behaviour of the vertical boundary layer equations near the corners of the cavity. Implications for the structure of the core flow are discussed. The present results, which are new, compare well with a recent numerical solution. Although the results are consistent with the standard hypothesis that the vertical boundary layers empty into the core, they are not in agreement with the corner behaviour previously suggested in the literature. The analysis of the vertical boundary layer structure is also applicable to cavity flows in electrically conducting fluids in the limit when magnetic drag is the dominant force.
TL;DR: In this article, the authors investigated functional similarities between hunger CRs and sign-tracking behavior in rats and found that the effect of the presence of a second lever was to facilitate responding to the original lever.
Abstract: Two experiments were conducted to investigate functional similarities between “hunger CRs” of Konorski’s (1967) model of appetitive classical conditioning and sign-tracking behavior in rats. Konorski’s model predicts that hunger CRs will be facilitated (1) when a nonrein-forced stimulus similar to the reinforced CS is introduced, and (2) when some CS presentations are unexpectedly nonreinforced. In Experiment 1, hungry rats acquired a leverpress response to a retractable lever that was paired with response-independent food. Following this training, a second lever was introduced whose presentation was not followed by food. The effect of the presence of this second lever was to facilitate responding to the original lever. In Experiment 2, single-lever autoshaping training was followed by a shift from 100% pairing of the lever with food to only 50% of the lever presentations being followed by food. The introduction of partial reinforcement produced an immediate and durable increase in leverpressing. The findings of both experiments are consistent with predictions from Konorski’s model of classical conditioning if sign-tracking is considered as a “hunger CR.”
TL;DR: Results of two experiments showed that the modality effect in serial recall of word lists is sharply reduced by high interitem phonological similarity and that the extent of this reduction is much the same irrespective of whether the lists are spoken by the subject or the experimenter.
Abstract: Results of two experiments showed that the modality effect in serial recall of word lists is sharply reduced by high interitem phonological similarity and that the extent of this reduction is much the same irrespective of whether the lists are spoken by the subject or the experimenter. These findings contradict an account of the modality effect recently proposed by Richardson (1979), but the data are entirely consistent with the belief that the effect originates in echoic memory.
TL;DR: In this paper, extended Huckel molecular orbital calculations on the related closo-platinaboranes (H3P)2Pt(B11H11)2- and closo carbaplatin-aborane (C2B9H11), showed that the larger slip distortions in the pentagonal bipyramidal derivatives can be attributed in large measure to the different metal-ligand interactions which are induced by the different elevation angles of the substituents on the pentagon faces of the ligands.
TL;DR: In this article, the hydroxyl absorption band at 3400 cm−1 was linked to thickness changes and to increasing hydrogen bonding and chelation, which suggests chemical bonds linking silane and metal.
Abstract: Specular reflectance infra-red spectroscopy has been used to elucidate the structure of thin films of silane coupling agents on aluminium. Changes in the hydroxyl absorption band at 3400 cm−1 were linked to thickness changes and to increasing hydrogen bonding and chelation. This suggests chemical bonds linking silane and metal. Only with the thinnest films is hydroxyl bonding dominant and able to influence the coherence of the silane film.
TL;DR: In this paper, the effect of the replacement of a metal compound by another in the presence of a suitable halogen compound has been investigated, and the results of a reasonably detailed study of the flame retardance conferred by several different compositions of a binary metal compound mixture have been obtained.
TL;DR: In this paper, an analysis is given of the structure of thermally driven cavity flows in fluid-saturated porous media, with particular emphasis on the description of diffusive layers near the horizontal surfaces.
Abstract: An analysis is given of the structure, at high Rayleigh numbers, of thermally driven cavity flows in fluid-saturated porous media. Particular emphasis is placed on the description of the diffusive layers near the horizontal surfaces. Solutions consistent with the core behaviour determined in part I of this series are obtained. These solutions, which are new, indicate that the horizontal boundary layers have a double structure in which the outer layer has a thickness O(R$^-\frac{1}{4}$), where R is the Rayleigh number. Corner interactions between the horizontal and the vertical boundary layers are also discussed, and the present theory provides a first-order description of the entire flow field.
TL;DR: It was concluded that only chromic acid etching and anodizing and phosphoric acid anodized are suitable for permanent primary structure repairs and grit blasting and some paste etches may be acceptable for temporary primary structure repair and for routine secondary structure repairs.
TL;DR: An integrated modelling methodology for metabolic and endocrine systems is presented, with particular emphasis given to model identification and validation and their inter-relationship.
TL;DR: In this paper, the equation de Morison pour les forces sur de petits objects dans un ecoulement instationnaire is appliqué au cas de la force horizontale, sur un cylindre horizontal, exercee par une onde solitaire.
TL;DR: In this article, the involvement of radicals ions in photo-reductive dehalogenation of aromatic halides to their parent hydrocarbons is investigated and evidence for their involvement in these reactions is presented.
TL;DR: In this paper, the formation of light-sensitive electrodes by coating a platinum mesh from an aqueous suspension of a semiconductor, is demonstrated, which behave as short-circuited semiconductor electrodes.
Abstract: The formation of light-sensitive electrodes by coating a platinum mesh from an aqueous suspension of a semiconductor, is demonstrated. They behave as short-circuited semiconductor electrodes, and the shortcircuiting can be reduced by incorporation of Teflon in the coating. The photochemistry of some little investigated or uninvestigated semiconductors (metallic oxides, sulphides and chromates) is described; all respond to visible light, all are unstable on irradiation, and only p-type Pb3O4 appears useful as a photocathode. Photoacoustic spectra of some of these materials are presented. The shortcomings, and possible improvements, of this photoelectrode preparation method are discussed.
TL;DR: In this article, three approaches have been used to elucidate the mechanism of combustion of decane in the cool-flame region, showing that the selectivity of initial oxidative attack on decane remains low over the whole of the slow combustion and coolflame regions between 440 and 680 K, suggesting that hydroxyl radicals are the main attacking species throughout.
Abstract: Three approaches have been used to elucidate the mechanism of combustion of decane in the cool-flame region. First, measurements have been made of cool-flame and ignition parameters. These show a well defined change in activation energy at about 530 K. Second, analytical studies have been made of the effect of increasing temperature on the combustion products. These indicate that hydroperoxide formation ceases and that C 10 O-heterocycles become the predominant products at 500-530 K; the relative amounts of decanal and decanone do not however change. Finally, small amounts of hydrogen bromide have been added. These cause the complete conversion of hydroperoxides into decanones even at low temperatures; no lower carbonyl compounds are formed above 500 K. This work has led to two principal conclusions. One, which is shown by all three methods of study, is that the cool-flame combustion of decane involves two distinct mechanisms with a transition at 500-530 K. The other is that the selectivity of initial oxidative attack on decane remains low over the whole of the slow combustion and cool-flame regions between 440 and 680 K, suggesting that hydroxyl radicals are the main attacking species throughout.
TL;DR: In this study it has been demonstrated that, for GBS, a neurological registry, based on HAA records, provided an excellent source of data to measure the incidence of the disease and potentially any change of incidence over time.
Abstract: A feasibility study has been carried out to determine whether a population-based registry of neurological disease can be established using the Hospital (Inpatient) Activity Analysis (HAA) records for England and Wales. The study provides a valuable opportunity to use and test the HAA system. The neurological disease chosen was the Guillain-Barre-Strohl syndrome (GBS), because it would be expected that most patients would be admitted to hospital, and recurrent attacks or chronicity are rare. In this study it has been demonstrated that, for GBS, a neurological registry, based on HAA records, provided an excellent source of data to measure the incidence of the disease and potentially any change of incidence over time. The proportion of coding errors was found to be under 5%.
TL;DR: In this paper, it was found that fast potentiostatic cycling (50 mVs−1) could regenerate the surface area of the Pt and recover the performance of the fuel cells.
Abstract: One of the main reasons for the decay in performance of phosphoric acid fuel cells (150° C) is the decrease in surface area of the platinum catalyst with time. It was found that fast potentiostatic cycling (50 mVs−1) could regenerate the surface area of the Pt and recover the performance. The mechanism of regeneration is likely to be charge injection, resulting in electrostatic repulsion of the platinum particles in the loosely held agglomerates.
TL;DR: In this paper, it was shown that pyrogenic silica, even when present in very small concentrations, has a striking smoke-suppressant influence, the magnitude of which is directly related to its total available surface area.
TL;DR: In this paper, the crystal structure of dichloro-S,S′bis(O-methylcysteinato)tin(IV), Cl2Sn{SCH2CH(NH2)-CoOMe}2, has been solved by a three-dimensional Patterson synthesis.
01 Sep 1982
TL;DR: The authors argue that plain English, simple language, and good style are frequently taken for granted. Yet, easily as such epithets may come to us, they, nevertheless, conceal issues concerning the use of language which are unlikely ever to be resolved in a satisfactory manner.
Abstract: ‘Plain English’, ‘simple language’ and ‘good style’ are frequently taken for granted. Yet, easily as such epithets may come to us, they, nevertheless, conceal issues concerning the use of language which are unlikely ever to be resolved in a satisfactory manner. The quotation from Through the Looking Glass illustrates one of the most enduring of these. Alice, perhaps because she is a child, supports the conservatives: strict rule‐followers who believe that English words have fixed and invariable meanings. Into this category also come those who hope to purge our language of foreign (especially American) influences, much like those who wish to eliminate all traces of ‘franglais’ from the French language. Humpty Dumpty represents the liberals—those who feel that words can change their meanings according to circumstances. This allows him to close the argument by claiming that: ‘I can explain all the poems that ever were invented—and a good many that haven't been invented just yet.’