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This paper describes the diagonal comultiplication (or cup coproduct) defined on integral homology modules of groups. Analysis of this coproduct should provide a new method of testing for non-isomorphism of groups which have isomorphic integral homology modules; here, the dimension two coproduct is applied to this problem. The first part (Section 2) is couched in terms of groupnets (Brandt groupoids) and shows two things: that there exists a cup product defined on the integral cohomology of any groupnet, extending that for groups, and that there exists a comultiplication defined on the integral homology of any group, natural up to dimension two, which gives the homology modules the structure of a commutative graded co-ring. In the second part (Sections 3 and 4), this diagonal comultiplication R is constructed to dimension two, and the information it carries about the lower central series of a group G is investigated. Modulo torsion in Hr(G; Z), Rz induces an abelian group homomorphism with cokernel GZ/G3, which distinguishes between large classes of groups, in particular the one-relator groups with non-trivial multiplicator, and the finitely-generated nilpotent groups of class two whose relators are all in the commutator subgroup.

This paper describes the diagonal comultiplication (or cup coproduct) defined on integral homology modules of groups. Analysis of this coproduct should provide a new method of testing for non-isomorphism of groups which have isomorphic integral homology modules; here, the dimension two coproduct is applied to this problem. The first part (Section 2) is couched in terms of groupnets (Brandt groupoids) and shows two things: that there exists a cup product defined on the integral cohomology of any groupnet, extending that for groups, and that there exists a comultiplication defined on the integral homology of any group, natural up to dimension two, which gives the homology modules the structure of a commutative graded co-ring. In the second part (Sections 3 and 4), this diagonal comultiplication R is constructed to dimension two, and the information it carries about the lower central series of a group G is investigated. Modulo torsion in Hr(G; Z), Rz induces an abelian group homomorphism with cokernel GZ/G3, which distinguishes between large classes of groups, in particular the one-relator groups with non-trivial multiplicator, and the finitely-generated nilpotent groups of class two whose relators are all in the commutator subgroup.

The c-axis resistance R of stage 2 SbCl5 intercalated graphite has been measured in the range 80–300 K and 0–4 GPa. The pressure dependence of R is similar to that of HOPG in the ordered low-T phase below 200 K but significantly larger at 300 K, where the initial pressure coefficient of R is −1.37 GPa−1. Two phase transitions are always observed under pressure, one at 0.3–0.5 GPa and one above 1 GPa. The latter is not completed until above 2.4 GPa and both are slow, with large time-dependent effects in R. R decreases by over 80% to 4 GPa., Editors: D. Davidov and H. Selig.

T. Kohonen has described an algorithm for fitting a k-dimensional grid of points to a set of points taken from a k-manifold in Rn, for k⩽n. The algorithm is inspired by a neural model and bears some of the marks of its ancestry. In this paper we show that if the process converges, it converges to a locally 1-1 mapping of the grid onto the manifold. Hitherto this result has only been proved for the case where k=1.

Dense (98.5%) bulk sintered specimens of YBa2Cu4O8 have been produced by hot isostatic pressing. Data for the electrical resistivity π versus temperature T and pressure p in the range 70–300 K and 0–0.7 GPa are reported and discussed. The critical current density of the material studied exceeds 100 Acm−2 below 60 K., Editor: D.S. Betts

Reliable modelling of soil-water flow requires accurate and convenient measurement of the appropriate soil hydraulic properties, which can be particularly problematic in structured soils with a distinct macropore-matrix dichotomy in the flow regime. In this paper the hydraulic properties of an aggregated soil at water supply potentials, Ψ0, near saturation are obtained using the disc permeameter. The sorptivity, S, the hydraulic conductivity, K(θ{symbol}), and the wetting soil-water characteristic, Ψ(θ{symbol}), are measured directly. The soil-water diffusivity, D(θ{symbol}), is derived from measurements of K(θ{symbol}) and Ψ(θ{symbol}) and is also shown to be well described by deconvoluting the sorptivity using the Parlange approximation. This description of D(θ{symbol}) conveniently supplements estimates obtained over a wider range of water contents using the absorption method of Bruce and Klute, with water content profiles obtained by gamma scanning. Finally, the measured K(θ{symbol}) function is accurately described by introduction of a method for scaling Ψ(θ{symbol}) over the inter- and intra-aggregate flow regions and matching to the measured hydraulic conductivity at two points.

This paper shows a certain equivalence between the 3-layer feed forward back-propagation neural net of Rumelhart et al. and the committee net of Nilsson. This is used to produce an improvement in the performance of the former. It is found that (a) the number of epochs taken is reduced by a factor of between 6 and 10, (b) the same taken is reduced by a factor of about 20, and (c) the net converges under conditions when the back-propagation algorithm is trapped in local minima and fails to converge.

This paper shows a certain equivalence between the 3-layer feed forward back-propagation neural net of Rumelhart et al. and the committee net of Nilsson. This is used to produce an improvement in the performance of the former. It is found that (a) the number of epochs taken is reduced by a factor of between 6 and 10, (b) the same taken is reduced by a factor of about 20, and (c) the net converges under conditions when the back-propagation algorithm is trapped in local minima and fails to converge.

Beating occurs when two coordination shells are closely spaced (δR ≈ 0.1 A ̊). Analyzing two such shells by curve fitting is difficult because the fit parameters exhibit enhanced correlation due to the reduced number of degrees of freedom. Analyzing the combined phase of the two shells in k-space, or its derivative with respect to k, can be performed with a reduced number of fit parameters because only the ratio of the two coordination numbers is required and, with a minor approximation, only the difference of the two EXAFS Debye-Waller factors is needed. Since the beating effect leads to structure that occurs localized in k-space and because this beating structure is usually at the high-k end (for very closely spaced coordination shells) one may neglect the effects of the energy corrections ΔE1 and ΔE2 for the origins of the two k-scales, thus reducing the number of fit parameters by another two. The beating effect can be investigated conveniently by analyzing the derivative of the combined phase of the two coordination shells in k-space. Then the occurrence of beating manifest itself by peaks or dips in the derivative function. This structure, however, can be modified significantly by effects resulting from the Fourier transform. In the present paper such Fourier transform artifacts, the effects of window functions and k-space weighting are taken into account

We have studied the structural, thermophysical, and spectroscopic properties of polymeric C60 obtained by high pressure treatment at pressures and temperatures near 1 GPa and 600 K. We present here a brief overview of our results for the structural and thermophysical properties and a more detailed report on recent results obtained by Raman spectroscopy on both thin films, polycrystalline, and single crystal material. The results presented include a comparison between Raman results for photopolymerized and pressure polymerized thin films and a preliminary estimate of the binding energy of polymeric C60., Editors: M.L.H. Green, M.J. Rosseinsky and E.S.C. Tsang.

We discuss the structural and dynamic properties of C60 polymerized under low-P, low-T conditions, and suggest that the disordered mixed orthorhombic-tetragonal-rhombohedral phases produced under these conditions arise from nucleation of molecular chains in random directions because of the quasi-free molecular rotation under standard reaction conditions in the fcc phase of C60. Polymerization in He gives results qualitatively different from those obtained in other media., Editors: Hans Kuzmany and Pierre Delhaes. Also reprinted in the Proceedings volume Fullerenes and Carbon Based Materials, E-MRS Symposia Proceedings Volume 68, Elsevier 1998, ISBN 0-444-20512-8, with the same Editors and page numbers.

We have investigated the electronic structure of one and two-dimensional C60 polymers with regard to both their low-lying excitations and C 1s excitation spectra by means of electron energy-loss spectroscopy in transmission. We compare the results with those for pristine C60. In general, the spectra for the polymers resemble those for pristine C60 but show a broadening due to both the lowering of the symmetry and the increased intermolecular overlap. This is also reflected by a reduction of the optical gap in comparison with pristine C60., Editors: P. Bernier, G. Bidan and S. Lefrant

This paper treats investment decision-making under uncertainty and risk. Some of the methods used for investment decision-making under uncertainty and risk are presented: Break-even Analysis, Sensitivity Analysis, Theory of Games and Decision Making Theory. Sensitivity Analysis is given special consideration, and one of the procedures of its application in investment decision making under uncertainty and risk is shown.

We show in this paper that characteristic features in the Raman spectra, especially the frequency of the pentagonal pinch mode, can give information about the polymeric structure of pressure polymerised C60. High-pressure treatment at 1 GPa below 510 K for 3 h results in the formation of a low fraction of dimers only, while treatment at the same pressure and time above 540 K affords a fully polymerised material. In the latter case, different relative fractions of dimers and polymer chains are obtained depending on whether the final reaction conditions were reached by isobaric or isothermal path. We suggest that this difference results from different reaction dynamics in the two cases. The polymerisation rate depends on T and p and on the rotational and orientational states of the molecules. At 1 GPa no polymerisation is observed in sc C60, while in “hexagon” oriented sc C60 at 1.7 GPa dimers are already formed 175 K below the fcc–sc transition and a fully polymerised material is obtained just below the transition to the fcc phase.

The strong intramolecular bonds and very weak intermolecular bonds in fullerenes such as C60 lead to a strong pressure dependence in many of their physical properties and to subtle structural changes under pressure. Compression of the lattice in combination with orientational ordering also enables rather easy formation of covalent intermolecular bonds under pressure, such that treatment at high pressure and high temperature leads to the formation of several different polymeric phases. Some recent experimental results on the structure and properties of C60 under high pressure are discussed, with particular emphasis on the effects of changes in the orientational structure on the bulk modulus and the effects of polymer dimensionality on the macroscopic physical properties of C60 polymers, respectively., Editors: G.G.N. Angilella, R. Pucci, G. Piccitto and F. Siringo.Invited review paper.

This paper reviews recent progress in relating the incidence of water repellency to other soil attributes, relating the severity of water repellency to different soil management and landuses and determining the value of soil survey in predicting the risk of water repellency. Data sets of soils from south-western Australia are used for this analysis. The relationship between water repellency and other soil attributes such as clay and organic matter contents has been found to be multivariate in nature, with a general form: Water repellency ≃ a Organic Matterb/Clay(c) where a, b and c are constants. Multiple regressions, which use a variety of attributes related to soil organic matter and soil surface area (e.g. clay, silt, amorphous iron contents), can explain up to 63% of the variation in water repellency. Water repellency increases in severity with increasing organic carbon content or decreasing soil surface area and vice versa. This relationship explains the poor or non-existent bivariate relationships between various soil attributes and water repellency reported in several studies and allows the re-interpretation of studies into the effects of liming, zero-till and different rotation lengths on water repellency as each affect soil organic carbon (OC) content. It is also consistent with observations that water repellency is more prevalent on sandy soils and reported reductions in water repellency following applications of clay and fine inorganic materials. It similarly explains the occurrence of water repellency on soils with >5% clay; accumulation of sufficient amounts of OC can induce water repellency in any soil. Soil management and landuse affect water repellency. Water repellency is less severe in soils under crops compared to pastures and this has been considered as being caused by differences in organic matter composition. This is re-interpreted as being due to differences in organic matter amount as cultivation mineralises and dilutes soil organic matter in

This paper reviews recent progress in relating the incidence of water repellency to other soil attributes, relating the severity of water repellency to different soil management and landuses and determining the value of soil survey in predicting the risk of water repellency. Data sets of soils from south-western Australia are used for this analysis. The relationship between water repellency and other soil attributes such as clay and organic matter contents has been found to be multivariate in nature, with a general form: Water repellency ≃ a Organic Matterb/Clay(c) where a, b and c are constants. Multiple regressions, which use a variety of attributes related to soil organic matter and soil surface area (e.g. clay, silt, amorphous iron contents), can explain up to 63% of the variation in water repellency. Water repellency increases in severity with increasing organic carbon content or decreasing soil surface area and vice versa. This relationship explains the poor or non-existent bivariate relationships between various soil attributes and water repellency reported in several studies and allows the re-interpretation of studies into the effects of liming, zero-till and different rotation lengths on water repellency as each affect soil organic carbon (OC) content. It is also consistent with observations that water repellency is more prevalent on sandy soils and reported reductions in water repellency following applications of clay and fine inorganic materials. It similarly explains the occurrence of water repellency on soils with >5% clay; accumulation of sufficient amounts of OC can induce water repellency in any soil. Soil management and landuse affect water repellency. Water repellency is less severe in soils under crops compared to pastures and this has been considered as being caused by differences in organic matter composition. This is re-interpreted as being due to differences in organic matter amount as cultivation mineralises and dilutes soil organic matter in

Electrical resistivity and magnetoresistance were measured on samples with disordered structures synthesized from pure C60 and C70 at pressures in the range 8–12.5 GPa and temperatures of 900–1500 K. Different types of behaviour were observed: semimetallic, VRH and semiconducting, depending on the degree of disorder and the particular short-range order of the samples. A negative magnetoresistance was observed at T<10 K on samples with a semimetallic type of conductivity synthesized at 8 GPa pressure. The temperature dependence of resistivity in the sample with a disordered crystalline structure based on 3D-polymerized C60 molecules fits Mott's law for hopping conductivity. T3/2, T2 and T4 dependencies of conductivity are observed for samples with densities of 2.8 and 3.05 g/cm3 synthesized at a pressure of 12.5 GPa. The effect of hydrostatic pressure on the resistivity of cross-linked layered carbon structures obtained from C60 at P=8 GPa, T=1600 K was investigated up to 0.6 GPa at room temperature. An approximately linear decrease of resistivity was observed with a very small value of the derivative d ln ρ/dp=0.06 /GPa, which correlates with a very low compressibility of the material., Editors: D. Zhu and Hans Kuzmany

This paper presents a direct solution to the time-dependent Schrödinger equation describing electron scattering in nano structures. This approach provides complete quantum mechanical information on the transient state of the system under study and can be applied to nano structures with arbitrarily complex geometry. As an example, a small rectangular cavity coupled to a nano wire is studied in detail. Resonance behaviour is observed.

This paper presents a direct solution to the time-dependent Schrödinger equation describing electron scattering in nano structures. This approach provides complete quantum mechanical information on the transient state of the system under study and can be applied to nano structures with arbitrarily complex geometry. As an example, a small rectangular cavity coupled to a nano wire is studied in detail. Resonance behaviour is observed.

There are many classification problems in petroleum reservoir characterisation, an example being the recognition of lithofacies from well log data. Data classification is not an easy task when the data are not of numerical origin. This paper compares three approaches to classify porosity into groups (very poor, poor, fair, good) using petrographical characteristics described in linguistic terms. The three techniques used are an expert system approach, a supervised clustering approach, and a neural network approach. From the results applied to a core data set in Australia, we found that the techniques performed best in decreasing order of their requirement for significant user effort, for a low degree of benefit achieved.

There are many classification problems in petroleum reservoir characterisation, an example being the recognition of lithofacies from well log data. Data classification is not an easy task when the data are not of numerical origin. This paper compares three approaches to classify porosity into groups (very poor, poor, fair, good) using petrographical characteristics described in linguistic terms. The three techniques used are an expert system approach, a supervised clustering approach, and a neural network approach. From the results applied to a core data set in Australia, we found that the techniques performed best in decreasing order of their requirement for significant user effort, for a low degree of benefit achieved.

This paper presents an implemented system architecture for intelligent knowledge-based supervisory control (IKBSC) of a rolling mill process. A novel framework was developed to integrate an expert system with an existing supervisory control system. This resulting IKBSC system was applied to an aluminium hot rolling mill process to improve the shape of low-gauge plate. Trials have demonstrated the advantages of an architecture that integrates knowledge contained within data, plant and human resources with existing model-based systems.

Up to 10% of the soluble nickel and cobalt can report to the tailings of a pressure acid leach (PAL) process for the recovery of nickel from lateritic ores as a result of the difficulties associated with the poor settling characteristics of the autoclave discharge. This paper describes the results of laboratory and pilot-plant investigations aimed at establishing the potential for the application of a resin-in-pulp (RIP) process to improve the overall nickel and cobalt recoveries from such tailings. Small-scale batch tests in the laboratory established the technical feasibility and this was followed by several campaigns using a continuous six-stage miniplant which demonstrated that the process could achieve the desired results and which enabled a pilot plant to be designed. The integrated pilot plant operated on site at a local plant over a period of several months. The paper will discuss the results from this testwork, which has culminated in a preliminary process design for a full-scale plant. In addition, the more fundamental aspects associated with the adsorption and elution processes have been investigated and process models developed for these operations.

Up to 10% of the soluble nickel and cobalt can report to the tailings of a pressure acid leach (PAL) process for the recovery of nickel from lateritic ores as a result of the difficulties associated with the poor settling characteristics of the autoclave discharge. This paper describes the results of laboratory and pilot-plant investigations aimed at establishing the potential for the application of a resin-in-pulp (RIP) process to improve the overall nickel and cobalt recoveries from such tailings. Small-scale batch tests in the laboratory established the technical feasibility and this was followed by several campaigns using a continuous six-stage miniplant which demonstrated that the process could achieve the desired results and which enabled a pilot plant to be designed. The integrated pilot plant operated on site at a local plant over a period of several months. The paper will discuss the results from this testwork, which has culminated in a preliminary process design for a full-scale plant. In addition, the more fundamental aspects associated with the adsorption and elution processes have been investigated and process models developed for these operations.

Demand for live trivalent tick fever vaccine containing Babesia bovis, Babesia bigemina and Anaplasma centrale produced by the Department of Primary Industries, Queensland, has increased from less than 10,000 doses in 1988 to 500,000 doses in 2001. This paper describes a series of trials aimed at overcoming certain constraints to obtain B. bigemina parasitised erythrocytes (PEs) on a large enough scale from infected splenectomised calves to meet the demand. Passage through a series of splenectomised calves failed to increase the yield per calf but we showed that the dose rate of infected cells could be reduced from the long-time standard of 1×107 to 2.5×106 without affecting immunogenicity and still leaving a safety margin of at least 50-fold for infectivity. This change quadrupled the potential yield of doses per calf and allowed the DPI to meet the increased demand for B bigemina in vaccine. Due to the high cost and limited availability of suitable, health tested donors, calves previously infected with B. bovis or A. centrale were used to provide B. bigemina organisms but the practice resulted in red cell agglutination in some batches of prepared vaccine. A trial is described where B. bigemina-infected red cells were washed by centrifugation to remove agglutinating antibodies. Washing had no effect on parasite viability and this method is now in routine use in the production of trivalent vaccine.

In this study we compare simulated, water non-limited yields obtained from the use of actual daily radiation and temperature data against yields simulated with weather data estimated using linear interpolation (LI) from monthly means. Using LI-generated radiation and temperature data (instead of stochastically generated or actual data) greatly reduces the effort required for the simulation task. LI data do not have the day-to-day variations that occur naturally. This paper determines under what condition crop model yields are insensitive to this day-to-day variation. Four locations across Iran with different climates were selected for the study. For each location a complete set of 20-year daily radiation and temperature data were available. Another 20-year sets of daily data were produced by LI from monthly means values. For the assessment we used the wheat, maize and soybean models of Decision Support System for Agrotechnology Transfer (DSSAT) at several sowing dates. Generally, simulated crop yields using actual and LI weather data showed similar responses to sowing date. Across crop models and locations, mean, variance and distribution differences between yields simulated with actual and LI data were significant in 23, 24 and 22% of cases, respectively. In many cases, the lack of day-to-day variation in LI data and hence its inability to reproduce extreme temperatures (cold or hot events) caused these significant differences, especially at unseasonally early or late sowing dates. In other cases, over-prediction of biomass production with LI data resulted in an over-prediction of yield. However, this growth over-prediction is only significant where growing season air temperatures are optimal or supra optimal for growth and have a high day-to-day variation (standard deviation greater than 3.5 °C). We concluded that for conventional sowing dates and in situations where unseasonally high or low temperatures are either unlikely or of little importance, the LI method c

In this study we compare simulated, water non-limited yields obtained from the use of actual daily radiation and temperature data against yields simulated with weather data estimated using linear interpolation (LI) from monthly means. Using LI-generated radiation and temperature data (instead of stochastically generated or actual data) greatly reduces the effort required for the simulation task. LI data do not have the day-to-day variations that occur naturally. This paper determines under what condition crop model yields are insensitive to this day-to-day variation. Four locations across Iran with different climates were selected for the study. For each location a complete set of 20-year daily radiation and temperature data were available. Another 20-year sets of daily data were produced by LI from monthly means values. For the assessment we used the wheat, maize and soybean models of Decision Support System for Agrotechnology Transfer (DSSAT) at several sowing dates. Generally, simulated crop yields using actual and LI weather data showed similar responses to sowing date. Across crop models and locations, mean, variance and distribution differences between yields simulated with actual and LI data were significant in 23, 24 and 22% of cases, respectively. In many cases, the lack of day-to-day variation in LI data and hence its inability to reproduce extreme temperatures (cold or hot events) caused these significant differences, especially at unseasonally early or late sowing dates. In other cases, over-prediction of biomass production with LI data resulted in an over-prediction of yield. However, this growth over-prediction is only significant where growing season air temperatures are optimal or supra optimal for growth and have a high day-to-day variation (standard deviation greater than 3.5 °C). We concluded that for conventional sowing dates and in situations where unseasonally high or low temperatures are either unlikely or of little importance, the LI method c

In this study we compare simulated, water non-limited yields obtained from the use of actual daily radiation and temperature data against yields simulated with weather data estimated using linear interpolation (LI) from monthly means. Using LI-generated radiation and temperature data (instead of stochastically generated or actual data) greatly reduces the effort required for the simulation task. LI data do not have the day-to-day variations that occur naturally. This paper determines under what condition crop model yields are insensitive to this day-to-day variation. Four locations across Iran with different climates were selected for the study. For each location a complete set of 20-year daily radiation and temperature data were available. Another 20-year sets of daily data were produced by LI from monthly means values. For the assessment we used the wheat, maize and soybean models of Decision Support System for Agrotechnology Transfer (DSSAT) at several sowing dates. Generally, simulated crop yields using actual and LI weather data showed similar responses to sowing date. Across crop models and locations, mean, variance and distribution differences between yields simulated with actual and LI data were significant in 23, 24 and 22% of cases, respectively. In many cases, the lack of day-to-day variation in LI data and hence its inability to reproduce extreme temperatures (cold or hot events) caused these significant differences, especially at unseasonally early or late sowing dates. In other cases, over-prediction of biomass production with LI data resulted in an over-prediction of yield. However, this growth over-prediction is only significant where growing season air temperatures are optimal or supra optimal for growth and have a high day-to-day variation (standard deviation greater than 3.5 °C). We concluded that for conventional sowing dates and in situations where unseasonally high or low temperatures are either unlikely or of little importance, the LI method c

This paper attempts a rigorous computer simulation of the current transport in GaN and AlGaN Schottky diodes on the basis of the thin surface barrier (TSB) model recently proposed by the authors’ group. First, a computer program was developed which can calculate current transport through an arbitrary potential profile of Schottky barrier by a combined mechanism of thermionic emission (TE), thermionic-field emission (TFE) and field emission (FE). Then, from the view point of the TSB model, attempts were made to fit the theoretical temperature dependent current voltage (I–V–T) curves to the measured I–V–T data taken on Ni/n-GaN and Ni/n-AlGaN Schottky diodes changing the barrier profiles and the energy depth of the surface donor. As compared with the previous poor fitting using approximate analytic formulas, excellent fitting was obtained for both forward and reverse current, confirming the validity of the TSB model as the mechanism for anomalously large leakage currents in GaN and AlGaN Schottky diodes. Best fittings for GaN and Al 0.26 Ga 0.74 N were obtained for exponentially decaying distributions of surface defect donors with the peak density of 5 × 10(18) cm(−3) and 1 × 10(19) cm(−3), the characteristic decay depth of 11 nm and 11.5 nm and the energy depth of 0.25 eV and 0.37 eV, respectively.

This paper attempts a rigorous computer simulation of the current transport in GaN and AlGaN Schottky diodes on the basis of the thin surface barrier (TSB) model recently proposed by the authors’ group. First, a computer program was developed which can calculate current transport through an arbitrary potential profile of Schottky barrier by a combined mechanism of thermionic emission (TE), thermionic-field emission (TFE) and field emission (FE). Then, from the view point of the TSB model, attempts were made to fit the theoretical temperature dependent current voltage (I–V–T) curves to the measured I–V–T data taken on Ni/n-GaN and Ni/n-AlGaN Schottky diodes changing the barrier profiles and the energy depth of the surface donor. As compared with the previous poor fitting using approximate analytic formulas, excellent fitting was obtained for both forward and reverse current, confirming the validity of the TSB model as the mechanism for anomalously large leakage currents in GaN and AlGaN Schottky diodes. Best fittings for GaN and Al 0.26 Ga 0.74 N were obtained for exponentially decaying distributions of surface defect donors with the peak density of 5 × 10(18) cm(−3) and 1 × 10(19) cm(−3), the characteristic decay depth of 11 nm and 11.5 nm and the energy depth of 0.25 eV and 0.37 eV, respectively.

The list of documents returned by Internet search engines in response to a query these days can be quite overwhelming. There is an increasing need for organising this information and presenting it in a more compact and efficient manner. This paper describes a method developed for the automatic clustering of World Wide Web documents, according to their relevance to the user’s information needs, by using a hybrid neural network. The objective is to reduce the time and effort the user has to spend to find the information sought after. Clustering documents by features representative of their contents—in this case, key words and phrases—increases the effectiveness and efficiency of the search process. It is shown that a two-dimensional visual presentation of information on retrieved documents, instead of the traditional linear listing, can create a more user-friendly interface between a search engine and the user.

The list of documents returned by Internet search engines in response to a query these days can be quite overwhelming. There is an increasing need for organising this information and presenting it in a more compact and efficient manner. This paper describes a method developed for the automatic clustering of World Wide Web documents, according to their relevance to the user’s information needs, by using a hybrid neural network. The objective is to reduce the time and effort the user has to spend to find the information sought after. Clustering documents by features representative of their contents—in this case, key words and phrases—increases the effectiveness and efficiency of the search process. It is shown that a two-dimensional visual presentation of information on retrieved documents, instead of the traditional linear listing, can create a more user-friendly interface between a search engine and the user.

type:text, In this paper, we examined the basic properties in the 1:1 mixture of lithium amide LiNH2 and lithium hydride LiH as a candidate of reversible hydrogen storage materials. The thermal desorption mass spectra of the ball milled mixture without any catalysts indicated that hydrogen H2 is released in temperature range from 180 to 400 ℃ with emitting a considerable amount of ammonia NH3. On the other hand, the ball milled mixture containing a small amount of TiCl3 as a catalyst showed the most superior hydrogen storage properties among the 1:1 mixtures with a small amount of catalysts, Ni, Fe, Co metals and TiCl3 (1 mol.%). That is, the product desorbs a large amount of hydrogen (~5.5 wt.%) in the temperature from 150 to 250 ℃ under the condition of a heating rate of 5 ℃/min, but it does not desorb ammonia at all within our experimental accuracy. In addition, we confirmed that the product shows an excellent cycle retention with an effective hydrogen capacity of more than 5 wt.% and a high reaction rate until at least 3 cycles.

In this paper, we examined the basic properties in the 1:1 mixture of lithium amide LiNH2 and lithium hydride LiH as a candidate of reversible hydrogen storage materials. The thermal desorption mass spectra of the ball milled mixture without any catalysts indicated that hydrogen H2 is released in temperature range from 180 to 400 ℃ with emitting a considerable amount of ammonia NH3. On the other hand, the ball milled mixture containing a small amount of TiCl3 as a catalyst showed the most superior hydrogen storage properties among the 1:1 mixtures with a small amount of catalysts, Ni, Fe, Co metals and TiCl3 (1 mol.%). That is, the product desorbs a large amount of hydrogen (~5.5 wt.%) in the temperature from 150 to 250 ℃ under the condition of a heating rate of 5 ℃/min, but it does not desorb ammonia at all within our experimental accuracy. In addition, we confirmed that the product shows an excellent cycle retention with an effective hydrogen capacity of more than 5 wt.% and a high reaction rate until at least 3 cycles.

We have examined intercalated compounds of C60 containing four light alkali metal atoms per molecule. The single-metal compounds Na4C60 and Li4C60 form two-dimensional polymers with intermolecular links consisting of one and two C–C bonds, respectively. We have here studied the compounds NanLi(4-n)C60, with n between 0 and 4, to find out what parameters define the polymeric structure, in particular the type of intermolecular bonding. The materials have been studied by X-ray diffraction and Raman spectroscopy. Although the results are compatible with a charge transfer model with different charge transfers for Na and Li ions, other models cannot be ruled out because disorder and mixed phases complicate the analysis.

Crystalline and disordered 3D-polymeric C60 and C70 with different lattice parameters and with densities in the range of 2.2÷3.25 g cm−1 were obtained by high-pressure-high-temperature treatment at P=11.5÷15 GPa, T=670÷1800 K. Their d.c. electrical conductivity was investigated at temperatures 30÷350 K. The variable range hopping mechanism dominates in all samples up to room temperature. A temperature activated conductivity via delocalized states was observed at T>160÷260 K in crystalline C60 samples and in some samples with disordered structure. The evaluated band gap value is Eg=0.28÷0.54 eV for different crystalline structures and 0.06÷0.25 eV for disordered ones

This paper describes a novel networked control systems architecture in which the down-link communication system is designed to operate in two different modes. This achieves improved trade-offs between error probabilities and transmission delays. The method is illustrated for the case of a physical channel which can either function as an error-free delay (virtual) channel or as a delay-free erasure (virtual) channel with a given probability of error. It is shown how this architecture outperforms existing methods which make use of only one communication mode. Copyright copy; 2005 IFAC.

This paper provides a systematic study of inductive inference of indexable concept classes in learning scenarios where the learner is successful if its final hypothesis describes a finite variant of the target concept, i.e., learning with anomalies. Learning from positive data only and from both positive and negative data is distinguished. The following learning models are studied: learning in the limit, finite identification, set-driven learning, conservative inference, and behaviorally correct learning. The attention is focused on the case that the number of allowed anomalies is finite but not a priori bounded. However, results for the special case of learning with an a priori bounded number of anomalies are presented, too. Characterizations of the learning models with anomalies in terms of finite tell-tale sets are provided. The observed varieties in the degree of recursiveness of the relevant tell-tale sets are already sufficient to quantify the differences in the corresponding learning models with anomalies. Finally, a complete picture concerning the relations of all models of learning with and without anomalies mentioned above is derived.

This paper provides a systematic study of inductive inference of indexable concept classes in learning scenarios where the learner is successful if its final hypothesis describes a finite variant of the target concept, i.e., learning with anomalies. Learning from positive data only and from both positive and negative data is distinguished. The following learning models are studied: learning in the limit, finite identification, set-driven learning, conservative inference, and behaviorally correct learning. The attention is focused on the case that the number of allowed anomalies is finite but not a priori bounded. However, results for the special case of learning with an a priori bounded number of anomalies are presented, too. Characterizations of the learning models with anomalies in terms of finite tell-tale sets are provided. The observed varieties in the degree of recursiveness of the relevant tell-tale sets are already sufficient to quantify the differences in the corresponding learning models with anomalies. Finally, a complete picture concerning the relations of all models of learning with and without anomalies mentioned above is derived.

This paper provides a systematic study of inductive inference of indexable concept classes in learning scenarios where the learner is successful if its final hypothesis describes a finite variant of the target concept, i.e., learning with anomalies. Learning from positive data only and from both positive and negative data is distinguished. The following learning models are studied: learning in the limit, finite identification, set-driven learning, conservative inference, and behaviorally correct learning. The attention is focused on the case that the number of allowed anomalies is finite but not a priori bounded. However, results for the special case of learning with an a priori bounded number of anomalies are presented, too. Characterizations of the learning models with anomalies in terms of finite tell-tale sets are provided. The observed varieties in the degree of recursiveness of the relevant tell-tale sets are already sufficient to quantify the differences in the corresponding learning models with anomalies. Finally, a complete picture concerning the relations of all models of learning with and without anomalies mentioned above is derived.

This paper provides a systematic study of inductive inference of indexable concept classes in learning scenarios where the learner is successful if its final hypothesis describes a finite variant of the target concept, i.e., learning with anomalies. Learning from positive data only and from both positive and negative data is distinguished. The following learning models are studied: learning in the limit, finite identification, set-driven learning, conservative inference, and behaviorally correct learning. The attention is focused on the case that the number of allowed anomalies is finite but not a priori bounded. However, results for the special case of learning with an a priori bounded number of anomalies are presented, too. Characterizations of the learning models with anomalies in terms of finite tell-tale sets are provided. The observed varieties in the degree of recursiveness of the relevant tell-tale sets are already sufficient to quantify the differences in the corresponding learning models with anomalies. Finally, a complete picture concerning the relations of all models of learning with and without anomalies mentioned above is derived.

Network operators, service providers and customers are players who have different interests and raise different requirements on the functionality of future mobile communication networks. However, some new capabilities, such as mobility, security, ubiquity and quality are spelled out by all, which means that there exist some fundamental mechanisms which are in fact needed in every network. This paper concentrates on critical elements of the network infrastructure which need to be deployed in 4G networks before services can be offered. In the paper we discuss these elements, and show how they can be combined to satisfy versatile service requirements. Furthermore, the paper shows how to combine these mechanisms of three traditionally quite separate architectures-for Authentication, Authorisation, Accounting and Charging (AAAC), for Mobility (Mobile IP with Fast Handover), and Quality-of-Service (QoS). A technology-independent paging concept is also integrated in this system. The resulting integrated system architecture is general and can be deployed in heterogeneous environments. Our implementation has recently been completed, validated and verified with applications such as data transfer, voice-over-IP, video streaming and real time concurrent gaming. This prototypical implementation incorporates TD-CDMA, 802.11 WLANs and Ethernet, and treats all transmission technologies as physical and data-link layers, while higher-level functions are supported in a uniform way with an all-IPv6-based signalling.

Network operators, service providers and customers are players who have different interests and raise different requirements on the functionality of future mobile communication networks. However, some new capabilities, such as mobility, security, ubiquity and quality are spelled out by all, which means that there exist some fundamental mechanisms which are in fact needed in every network. This paper concentrates on critical elements of the network infrastructure which need to be deployed in 4G networks before services can be offered. In the paper we discuss these elements, and show how they can be combined to satisfy versatile service requirements. Furthermore, the paper shows how to combine these mechanisms of three traditionally quite separate architectures-for Authentication, Authorisation, Accounting and Charging (AAAC), for Mobility (Mobile IP with Fast Handover), and Quality-of-Service (QoS). A technology-independent paging concept is also integrated in this system. The resulting integrated system architecture is general and can be deployed in heterogeneous environments. Our implementation has recently been completed, validated and verified with applications such as data transfer, voice-over-IP, video streaming and real time concurrent gaming. This prototypical implementation incorporates TD-CDMA, 802.11 WLANs and Ethernet, and treats all transmission technologies as physical and data-link layers, while higher-level functions are supported in a uniform way with an all-IPv6-based signalling.

Consumer’s participation in service delivery is so central to cognition that it affects consumer’s quality evaluations. The study presented in this paper investigates the ways that visitor expectations change as a result of first hand experience with a service in the context of a major art exhibition. The research design allowed for two operational definitions of expectations, namely forecast and ideal expectations, in order to investigate differences between respondents’ pre and post experiences with a service. A total of 550 respondent visitors were interviewed during a major art exhibition, using two questionnaires delivered to two sub samples of respondents. The primary questionnaire was designed to capture recalled expectations after visitation while the parallel questionnaire captured forecast expectations prior to visitation and perceptions in the post experience phase. The findings suggest that forecast expectations were different to ideal expectations in both qualitative and quantitative ways and that these differences had important implications for perceptions of service quality. These differences can be explained, at least in part, by the way that expectations are formed and by the way that expectations are shaped by the actual visitation experience. For market researchers, the question of when and how to measure expectations has important implications for research design.

This paper characterizes general properties of an economy that experiences deflation by investigating the long-run government budget constraint. A sufficient condition for deflation in an economy under a balanced budget is that the nominal interest rate is below the output growth rate. With a primary deficit, deflation occurs in a liquidity trap if the government is heavily in debt. Simple budget arithmetic reveals that it is never possible to finance a negative currency seigniorage by rolling over the public debt.

This paper characterizes general properties of an economy that experiences deflation by investigating the long-run government budget constraint. A sufficient condition for deflation in an economy under a balanced budget is that the nominal interest rate is below the output growth rate. With a primary deficit, deflation occurs in a liquidity trap if the government is heavily in debt. Simple budget arithmetic reveals that it is never possible to finance a negative currency seigniorage by rolling over the public debt.

Bibliometric methods for analysing and describing research output have been supported internationally by the establishment and operation of organisations such as the Institute for Scientific Information (ISI) as well as the continual calculations and release of journal lists, bibliometric indicators and rankings. Policy makers in Australia have been relying on such bibliometric information and analyses in making funding decisions and encouraging the development of research potential and strengths. Does bibliometric modelling of research productivity reflect the real impact research has for Australia's future? The paper is based on a study of three Australian research centres in the field of the geosciences. The analysis reveals a number of anomalies in the generalisations made when ISI models are used for policy decisions.

Bibliometric methods for analysing and describing research output have been supported internationally by the establishment and operation of organisations such as the Institute for Scientific Information (ISI) as well as the continual calculations and release of journal lists, bibliometric indicators and rankings. Policy makers in Australia have been relying on such bibliometric information and analyses in making funding decisions and encouraging the development of research potential and strengths. Does bibliometric modelling of research productivity reflect the real impact research has for Australia's future? The paper is based on a study of three Australian research centres in the field of the geosciences. The analysis reveals a number of anomalies in the generalisations made when ISI models are used for policy decisions.

Opportunities to make sequential decisions and adjust activities as a season progresses and more information becomes available characterise the farm management process. In this paper, we present a discrete stochastic two-stage utility efficient programming model of organic dairy farms, which includes risk aversion in the decision maker’s objective function as well as both embedded risk (stochastic programming with recourse) and non-embedded risk (stochastic programming without recourse). Historical farm accountancy data and subjective judgements were combined to assess the nature of the uncertainty that affects the possible consequences of the decisions. The programming model was used within a stochastic dominance framework to examine optimal strategies in organic dairy systems in Norway.