bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Amine Fluoride on Biofilm Growth and Salivary Pellicles
Authors: van der Mei H.C. , Engels E. , de Vries J. , Busscher H.J.
Published: November 2007

The amine fluoride (AmF) N′-octadecyltrimethylendiamine-N,N,N′-tris(2-ethanol)-dihydrofluoride is a cationic antimicrobial which can have beneficial effects on plaque formation. Here, we determine changes in pellicle and bacterial cell surface properties of the strains Actinomyces naeslundii HM1, Streptococcus mutans NS, S.mutans ATCC 700610, S. sobrinus HG1025 and S. oralis HM1 upon adsorption of this AmF and accompanying effects on bacterial adhesion and biofilm growth. In vitro pellicles had a zeta potential of –12 mV that became less negative upon adsorption of AmF. The chemical functionalities in which carbon and oxygen were involved changed after AmF adsorption and AmF-treated pellicles had a greater surface roughness than untreated pellicles. Water contact angles in vitro decreased from 56 to 45° upon AmF treatment, which corresponded with water contact angles (44°) measured intraorally on the front incisors of volunteers immediately after using an AmF-containing toothpaste. All bacterial strains were negatively charged and their isoelectric points (IEP) increased upon AmF adsorption. Minimal inhibitory concentrations were smallest for strains exhibiting the largest increase in IEP. Adhesion to salivary pellicles and biofilm growth of the mutans streptococcal strains were significantly reduced after AmF treatment, but not of A. naeslundii or S. oralis. However, regardless of the strain involved, biofilm viability decreased significantly after AmF treatment. The electrostatic interaction between cationic AmF and negatively charged bacterial cell surfaces is pivotal in establishing reduced biofilm formation by AmF through a combination of effects on initial adhesion and killing. The major effect of AmF treatment, however, was a reduction brought about in biofilm viability.
Influence of Salivary Macromolecules and Fluoride on Enamel Lesion Remineralization in vitro
Authors: Fujikawa H. , Matsuyama K. , Uchiyama A. , Nakashima S. , Ujiie T.
Published: November 2007

The aim of this study was to investigate the influence of salivary macromolecules on enamel lesion remineralization in the presence or absence of fluoride. Paraffin-stimulated whole saliva was centrifuged, and the supernatant was dialyzed in 1,000 molecular-weight cutoff dialysis tubes, first against a phosphate buffer and then against a mineral solution containing Ca and phosphate. Artificial subsurface lesions of human enamel, created in pH 4.5 acetate buffer, were remineralized for 28 days in 4 remineralizing solutions: group C – mineral solution as a control; group S – mineral solution + dialyzed saliva; group F – mineral solution + 1 ppm F; group SF – mineral solution + dialyzed saliva + 1 ppm F. Changes in relative mineral concentration in the lesions were assessed by transverse microradiography. The results showed statistically significant mineral gains in the lesion body in groups C (ΔZ = 3,254 ± 1,562% ×µm) and SF (ΔZ = 2,973 ± 1,349% ×µm), but not in groups S (ΔZ = 5,192 ± 1,863% ×µm) and F (ΔZ = 4,310 ± 1,138% ×µm) compared with the baseline group (ΔZ = 5,414 ± 461% ×µm). It was also found that the mineral density at the surface layer in group F (75.0 ± 15.7%) was greater than that in the baseline group (30.1 ± 12.3%) with statistical significance, but not in group SF (39.9 ± 16.5%). It was concluded that the macromolecules inhibited lesion remineralization fundamentally but that these molecules, in the presence of fluoride, seemed to play an important role in the continuation of remineralization by reducing mineral gains at the surface layer.
Variability of Exhaled Breath Condensate pH in Lung Transplant Recipients
Authors: Czebe Krisztina , Kullmann Tamas , Csiszer Eszter , Barat Erzsebet , Horvath Ildiko , Antus Balazs
Published: November 2007

Background: Measurement of pH in exhaled breath condensate (EBC) may represent a novel method for investigating airway pathology. Objectives: The aim of this longitudinal study was to assess the variability of EBC pH in stable lung transplant recipients (LTR). Methods: During routine clinical visits 74 EBC pH measurements were performed in 17 LTR. EBC pH was also measured in 19 healthy volunteers on four separate occasions. EBC pH was determined at standard CO2 partial pressure by a blood gas analyzer. Results: Mean EBC pH in clinically stable LTR and in controls was similar (6.38 ± 0.09 vs. 6.44 ± 0.16; p =nonsignificant). Coefficient of variation for pH in LTR and controls was 2.1 and 2.3%, respectively. The limits of agreement for between-visit variability determined by the Bland-Altman test in LTR and healthy volunteers were also comparable (–0.29 and 0.46 vs. –0.53 and 0.44). Conclusions: Our data suggest that the variability of EBC pH in stable LTR is relatively small, and it is similar to that in healthy nontransplant subjects.
The Population and Vital Rates of the Jesuit Missions of Paraguay, 1700–1767
Authors: Jackson Robert H.
Published: November 2007

Massimo Livi-Bacci and Ernesto Maeder's analysis of demographic trends in the Jesuit missions of Paraguay (“The Missions of Paraguay: The Demography of an Experiment,” Journal of Interdisciplinary History, XXXV [2004], 185–224) is flawed. Though offering important insights, it relies on general findings at the expense of significant regional variations, and it ignores sources, such as tribute censuses, that supply telling details about individual missions.
Priscian on Divine Ideas and Mental Conceptions: The Discussions in the Glosulae in Priscianum, the Notae Dunelmenses, William of Champeaux and Abelard
Authors: Rosier-Catach Irène
Published: November 2007

Priscian's Institutiones Grammaticae, which rely on Stoic and Neoplatonic sources, constituted an important, although quite neglected, link in the chain of transmission of ancient philosophy in the Middle Ages. There is, in particular, a passage where Priscian discusses the vexed claim that common names can be proper names of the universal species and where he talks about the ideas existing in the divine mind. At the beginning of the 12th century, the anonymous Glosulae super Priscianum and the Notae Dunelmenses, which heavily quote William of Champeaux (as master G.), interpret the passage in the context of a growing interest in the problem of universals, raising semantic as well as ontological questions, and introducing a Platonic view on universals in the discussions on the signification of the noun. Moreover, this same passage will be used by Abelard to elaborate one of his opinions about the signification of universal or common names—that they signify "mental conceptions".
Symbolism and Linguistic Semantics. Some Questions (and Confusions) from Late Antique Neoplatonism up to Eriugena
Authors: Bonfiglioli Stefania , Marmo Costantino
Published: November 2007

The notion of 'symbol' in Eriugena's writing is far from clear. It has an ambiguous semantic connection with other terms such as 'signification', 'figure', 'allegory', 'veil', 'agalma', 'form', 'shadow', 'mystery' and so on. This paper aims to explore into the origins of such a semantic ambiguity, already present in the texts of the pseudo-Dionysian corpus which Eriugena translated and commented upon. In the probable Neoplatonic sources of this corpus, the Greek term symbolon shares some aspects of its meaning with other words inherited from the ancient tradition, such as synthēma , eikōn , homoiotēs. Some of them, such as eikōn and homoiotēs, belong to the field of images and are associated with linguistic semantics in the Neoplatonic commentaries not only to Plato but also to Aristotle's logical works. Among the late ancient Neoplatonists, particular attention is paid to Proclus and to his use of the term agalma. In fact, the textual history of this word seems to be a privileged perspective from which to reconstruct the Neoplatonic semantic blending of symbol and image, as well as the main role played by linguistic issues in this conflation.
Theory of Supposition vs. Theory of Fallacies in Ockham
Authors: Novaes Catarina Dutilh
Published: November 2007

I propose to examine the issue of whether the ancient tradition in logic continued to be developed in the later medieval period from the vantage point of the relations between two specific groups of theories, namely the medieval theories of supposition and the (originally) ancient theories of fallacies. More specifically, I examine whether supposition theories absorbed and replaced theories of fallacies, or whether the latter continued to exist, with respect to one particular author, William of Ockham. I compare different parts of Ockham's Summa Logicae, namely III-4 (on fallacies), and the final chapters of part I and first chapters of part II (on supposition). I conclude that there is overlap of conceptual apparatus and of goals (concerning propositions that must be distinguished) in Ockham's theories of supposition and of fallacies, but that the respective conceptual apparatuses also present substantial dissimilarities. Hence, theories of supposition are better seen as an addition to the general logical framework that medieval authors had inherited from ancient times, rather than the replacement of an ancient tradition by a medieval one. Indeed, supposition theories and fallacy theories had different tasks to fulfil, and in this sense both had their place in fourteenth century logic.
Relationship between Vegetation Biophysical Properties and Surface Temperature Using Multisensor Satellite Data
Authors: Hong Seungbum , Lakshmi Venkat , Small Eric E.
Published: November 2007

Vegetation is an important factor in global climatic variability and plays a key role in the complex interactions between the land surface and the atmosphere. This study focuses on the spatial and temporal variability of vegetation and its relationship with land–atmosphere interactions. The authors have analyzed the vegetation water content (VegWC) from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), the leaf area index (LAI), the normalized difference vegetation index (NDVI), the land surface temperature (Ts), and the Moderate Resolution Imaging Spectroradiometer (MODIS). Three regions, which have climatically differing characteristics, have been selected: the North America Monsoon System (NAMS) region, the Southern Great Plains (SGP) region, and the Little River Watershed in Tifton, Georgia. Temporal analyses were performed by comparing satellite observations from 2003 and 2004. The introduction of the normalized vegetation water content (NVegWC) derived as the ratio of VegWC and LAI corresponding to the amount of water in individual leaves has been estimated and this yields significant correlation with NDVI and Ts. The analysis of the NVegWC–NDVI relationship in the above listed three regions displays a negative exponential relation, and the Ts–NDVI relationship (TvX relationship) is inversely proportional. The correlation between these variables is higher in arid areas such as the NAMS region, and becomes less correlated in the more humid and more vegetated regions such as the area of eastern Georgia. A land-cover map is used to examine the influence of vegetation types on the vegetation biophysical and surface temperature relationships. The regional distribution of vegetation reflects the relationship between the vegetation biological characteristics of water and the growing environment.
Fifty-Seven-Year California Reanalysis Downscaling at 10 km (CaRD10). Part I: System Detail and Validation with Observations
Authors: Kanamitsu Masao , Kanamaru Hideki
Published: November 2007

For the purpose of producing datasets for regional-scale climate change research and application, the NCEP–NCAR reanalysis for the period 1948–2005 was dynamically downscaled to hourly, 10-km resolution over California using the Regional Spectral Model.

This is Part I of a two-part paper, describing the details of the downscaling system and comparing the downscaled analysis [California Reanalysis Downscaling at 10 km (CaRD10)] against observation and global analysis. An extensive validation of the downscaled analysis was performed using station observations, Higgins gridded precipitation analysis, and Precipitation-Elevation Regression on Independent Slopes Model (PRISM) precipitation analysis.

In general, the CaRD10 near-surface wind and temperature fit better to regional-scale station observations than the NCEP–NCAR reanalysis used to force the regional model, supporting the premise that the regional downscaling is a viable method to attain regional detail from large-scale analysis. This advantage of CaRD10 was found on all time scales, ranging from hourly to decadal scales (i.e., from diurnal variation to multidecadal trend).

Dynamically downscaled analysis provides ways to study various regional climate phenomena of different time scales because all produced variables are dynamically, physically, and hydrologically consistent. However, the CaRD10 is not free from problems. It suffers from positive bias in precipitation for heavy precipitation events. The CaRD10 is inaccurate near the lateral boundary where regional detail is damped by the lateral boundary relaxation. It is important to understand these limitations before the downscaled analysis is used for research.
Employment Insecurity at Labour Market Entry and Its Impact on Parental Home Leaving and Family Formation
Authors: Wolbers Maarten H. J.
Published: November 2007

This article explores whether employment insecurity (i.e. unemployment and flexible employment) at labour market entry has a negative impact on parental home leaving and family formation. To answer this question, data from a large-scale European graduate survey carried out in 1998 were analysed. The results show that graduates with an insecure employment status at labour market entry are indeed less likely to leave the parental home and establish a nuclear household and family than those with stable first employment. With regard to entry into marriage and parenthood, these results especially hold true for men. Furthermore, it is found that in European countries in which unemployment among tertiary education graduates is high, the likelihood of leaving the parental home and starting a nuclear household and family is smaller than in European countries where such unemployment is low.
Speaking of Globalization
Authors: Essary Elizabeth Helen
Published: November 2007

This article introduces the concept of global frames as a means of measuring the degree to which individuals reference transnationalism in their interpretations of various events. Over the past few decades, institutional actors within world society have incorporated a language of globality into the public discourse, and this article examines whether this trend has become visible at the micro-level. The utility of this concept is illustrated using coded newspaper editorials from Canada and the United States in 2001 and 2003. Nearly one-fifth of the sampled editorials used a global frame, meaning that individuals do adopt the rhetoric established in the public sphere. Editorials that discussed either the US-Iraq Conflict or events that involved multiple countries were significantly more likely to use a global frame. In addition, US editorials used global frames at a higher rate than Canadian editorials. Thus, global framing is patterned by both shifts in public discourse and the persistent relevance of national borders.
Textile-specific Properties that Influence Plasma Treatment, Effect Creation and Effect Characterization
Authors: Verschuren Jo , Kiekens Paul , Leys Christophe
Published: November 2007

This paper discusses specific properties of textile products that influence plasma-textile interactions and impede both the fundamental understanding and the commercial application of plasma technology in the textile industry: (a) a large specific surface, (b) the three-dimensional porous structure and (c) the presence of impurities at the fiber surface, as well as in the fiber structure. The paper also clarifies the need for “plasma-for-textiles” i.e. a generic approach to the plasma treatment of textiles.
A thermal mass flowmeter suitable for interfacing with a microcomputer
Authors: Wardle A.P. , Feyo de Azevedo S.
Published: November 2007

The design and construction of a simple and inexpensive mass flowmeter based on a miniature bead thermistor and suitable for direct interfacing with a microcomputer or dedicated microprocessor is reported. Parameter estima tion techniques are employed to derive the nonlinear relationship between the potential difference across that part of the thermistor circuit connected to the interface and the mass flowrate of air at different working pressures. It is shown that the meter is accurate generally to within 8% of the true mass flowrate provided that the temperature of the bead does not vary by more than 30K. The meter has a relatively short response time, and maximum temperature safety control can be incorporated with ease.
A low cost solution for high-speed digital control
Authors: Goodall R.M. , Sutton D.G.
Published: November 2007

A concept for implementing digital control is described which is simple and cheap, and yet makes it possible for high performance to be achieved by employing a number of 'single chip micro-controllers'. The scheme is versatile, the key being that for each feedback loop a separate micro-controller is used, each having an associated analogue-to-digital converter. Each micro-controller runs asynchronously, with internal communication being provided to transfer data from one control loop to the next.
Dynamic weighing in a hostile environment
Authors: Whitehead D.G. , Fleming A.R. , Bell I.M. , Pugh A. , Sweeting P.
Published: November 2007

Check weighing of products during manufacture is required frequently. Commonly, these products are to be weighed while moving through the manufacturing process. This paper describes a method for capturing the weight of such products 'on the fly' using digital filters to extract the signal from the high ambient noise. A repeatability of better than ±0.3% in weight acquisition can be obtained by this approach.
Determination of elliptic error in measuring the complex S-parameters
Authors: Malešev Milutin
Published: November 2007

This paper proposes the new method for determining the random error in measuring the complex S-parameters- elliptic error. The measurements on two antennas making a two-port network were carried out and the elliptic error was calculated in parameters S21 for σ p, 2σp and 3σp.
Robot model validation
Authors: Gawthrop P.J. , Li X.
Published: November 2007

Some initial results arising from a project involving robot validation are described. A theme of the project is that control, whether adaptive or non-adaptive, should be model-based; that is, the controller should contain a model of the dynamic system describing the robotic manipulator. Good control requires a good model, and obtaining such a model is the aim of the validation exercise. The paper focuses on validating models of three components of the robot system: link flexibility, DC motors, and manipulator dynamics. In each case, algorithms, simulation and experimental results are presented. The use of symbolic algebra techniques is emphasised.

Relationships with other area of control and systems theory are explored. In particular, the relationships with parameter identification and fault detection are noted.
Two-dimensional discrete system stability
Authors: Whalley R.
Published: November 2007

Stability criteria for multi-dimensional discrete system models in the Z-transform variable are considered. A simple algebraic test for two-dimensional, scalar system assessment is derived, and illustrative examples are presented.
A self-learning fault-diagnosis system
Authors: Zhang J. , Roberts P.D. , Ellis J.E.
Published: November 2007

This paper describes a self-learning fault-diagnosis system which can find any inappropriate settings of its parameters and, hence, improve its own performance. It diagnoses faults based on a deep qualitative model of the process being monitored. From this qualitative model, the expected behaviour of the process can be generated and, if it differs from the actual one, then it is perceived that a fault (or faults) occurs in the process. The diagnosis of sensor failures is based on a set of heuristic rules, while the other component failures are diagnosed by comparing the expected behaviour under a hypothesis with the actual one. The inappropriate settings of any threshold values, for converting quantitative values to qualitative values and for determining symptoms in the perception of sensor failures, are considered as a major reason for failures in diagnosis. Once such a failure occurs, the diagnosis system will inspect itself and find any inappropriate parameters. This is achieved by examining the recorded problem-solving history and performing backwards tracing through the model of the fault-diagnosis system. The expected output of the fault-diagnosis system is propagated backwards through this model. Any threshold values which are responsible for not giving the expected output are examined, and the inappropriate parameters are found. This self-learning fault-diagnosis system has been implemented in an expert systems shell: EXTRAN, and is applied to a pilot-scale mixing process.
Electronics and computers in thermal systems: Reviewing current trends
Authors: McGhee J. , Henderson I.A. , Sankowskit D.
Published: November 2007

The paper surveys the influence of information technology upon temperature measurement and control systems. To bring order to the wide range of possibilities, a functional reticulation or classification of information machines is given. This helps in gaining a deep understanding of the role and impact of electronics and computers upon thermal systems in terms of the practical improvements they have allowed. Important features included in commercially available instruments are described. Future trends in the application of artificial intelligence and knowledge expertise in thermal sensors and controllers as well as in thermal system design are highlighted.
A study of the equations for platinum-resistance thermometry in the International Temperature Scale of 1990
Authors: Atherton A.
Published: November 2007

The introduction of ITS-90 has prompted an investigation of its compatibility with its predecessor, IPTS-68. In addition, criteria that govern the degree of mutual consistency of the ITS-90 deviation functions are derived and alternative approximate forms suggested for use particularly in cases for which explicit expressions are not available.
Performance weight selection for H-infinity and μ-control methods
Authors: Lundström Petter , Skogestad Sigurd , Wang Zi-Qin
Published: November 2007

The paper discusses, from a process control perspective, different approaches to performance weight selection when using H-infinity objectives. Approach A considers direct bounds on important transfer functions such as sensitivity and complementary sensitivity. Approach B considers the output response to sinusoidal disturbances, setpoints and noise. We also give some insight into the practical use of H-infinity and μ methods. μ is the structured singular value (SSV) introduced by Doyle (1982). μ-synthesis is generally not a convex optimisation problem and is presently not straightforward. We will discuss some of the problems we have encountered.
A model-based expert control system for MWD in the manufacture of polyester
Authors: Wang H. , Cameron R.G. , Johnson A.F.
Published: November 2007

This paper reports a novel strategy for molecular weight distribution (MWD) control of polyethylene terephthalate during the polymerisation process which has been successfully implemented for the first time in an industrial polyester plant. The strategy combines prediction of the product properties using a mathematical model, and interpretation of the prediction using pattern recognition and an on-line expert system. Operational experience shows that the new system yields significant technical and economic benefits.
Symbolic mathematics in control system analysis and design
Authors: Barker H.A. , Harvey I.T. , Townsend P.
Published: November 2007

Symbolic mathematical techniques and computer algebra systems have yet to be widely applied within the field of control. The benefits they have to offer in terms of greater accuracy and clarity of solutions for system analysis and design have yet to be fully exploited. This paper discusses these benefits and the facilities required by the user to support the use of symbolic algorithms and computer algebra systems for analysis of dynamic systems. These facilities include the means to store, edit and manipulate symbolic mathematical representations of the properties of a system. The methods by which this data may be used for analytical investigation by both symbolic and numerical packages are discussed. Finally, an implementation of such facilities within an integrated graphical environment for control engineering is described.
Design and performance evaluation of optimal multiple bluff body vortex flowmeters
Authors: Benson R.A. , Bentley J.P.
Published: November 2007

The paper begins by reviewing earlier work on the development of optimal dual bluff body vortex flowmeters. The five possible basic conditions underlying optimum vortex shedding from arrangements of two rectangular bluff bodies in tandem are then discussed. These conditions are then used to define optimal triple bluff body combinations where at least one of the two dual combinations which make up the triple is optimal. The performance of optimal triple combinations, non-optimal triple combinations, optimal dual combinations and an optimal single bluff body were then compared using a scan test. Here the vortex field downstream of a given combination was measured as a function of x, y position coordinates at a given free stream velocity and turbulence level. The results of this scan test are presented and are used to select three optimal combinations for further testing. A performance test was then carried out on these three optimal triples, the two optimal duals and the optimal single defined earlier. In a performance test, the sensor was first fixed at a position corresponding to optimum vortex shedding. RMS vortex velocity, signal-to-noise ratio, meter factor and a percentage frequency standard deviation were then measured over a range of free stream velocities and at medium and high turbulence. The results of this test are presented and show that the triple combinations perform better than the duals which in turn perform better than the single bluff body.
Parallel computing in CACSD
Authors: Chipperfield A.J. , Fleming P.J.
Published: November 2007

Computer-aided design of control systems via multiobjective optimisation is a computationally demanding task that may benefit from parallel processing techniques. In this paper, we report on a new parallel processing gateway that supports the use of parallel processing within the framework of an existing computer-aided control system design software package. In many control system design exercises which employ optimisation, the bulk of the computational effort is devoted to the evaluation of the objectives of the optimisation at each iteration. This paper demonstrates, with an example, how, using the gateway, parallel processing can be used within the framework of existing computer-aided control system design tools to compute these objective values.
A prognostic maintenance system based on the Hough Transformation
Authors: Flint A.D.
Published: November 2007

An automated predictive maintenance system has been developed based on the Hough Transform. The Hough Transform, used in image processing to extract geometrical primitives from image data, has been adapted to extract linear trend features from monitored data. The predictive maintenance system uses the extracted trend features to diagnose incipient fault conditions. It then predicts the time for the system to reach a critical fault condition. The transform provides an early warning of a developing fault allowing operating staff to anticipate the types of maintenance required before secondary damage and complete breakdown occurs. It can also deal robustly with noisy data, including impulsive noise.

It is proposed that logistic curves may be useful for the empirical description of wear failure. A multi-point generalisation of the Hough Transform (Flint et al, 1992) was developed for extracting logistic features from developing fault signatures. The new generalisation of the Hough Transform differs from earlier generalisations by incorporating early data fusion to reduce the size of previously large cumbersome arrays.

A brief description is given of the Hough Transform's application to two predictive maintenance case studies. The first case study is the uni-feature problem of providing predictive maintenance decisions for a diesel-engine lubricating oil system. The subject of the second case study is a pneumatic sliding-door system. Here a multivariate generalisation of the Hough Transform is required. The proposed generalisation involves the accumulation of vector rather than scalar votes in an array.
Reflections on calibration of platinum resistance thermometers
Authors: Atherton A.
Published: November 2007

A brief introduction to the meaning of temperature, thermal equilibrium and temperature scales is followed by a general description of methods used for calibrating platinum resistance thermometers (PRTs). Additionally, discussion is afforded to some of the more indirect and subtle influences (that are often ignored) at work during the application of calibration and measurement procedures. Also included is a suggested method of assessing self-heating in an environment that is physically non-static. Instrumentation is not considered in detail.
An adaptive power system stabiliser designed in the frequency domain
Authors: Hogg B.W. , Wang H.F.
Published: November 2007

This paper presents a new adaptive Power System Stabiliser (PSS) designed in the frequency domain, which has been developed and implemented in the laboratory using a multi-transputer system. This stabiliser tracks the variations of operating conditions and system configurations of power systems by estimating the oscillations occurring in the systems, and adjusts its parameters on-line to supply required damping to suppress the oscillations. Nonlinear simulations of an unstable power system and experimental results on a laboratory model power system show that this adaptive PSS possesses good robustness to changes of the operating conditions and system configurations, and can considerably improve the system stability.
A high-performance multi-arm environment: path planning and practical implementation
Authors: Dodds G.I. , Irwin G.W. , Zalzala A.M.S.
Published: November 2007

This paper reports on the development of a working multi-arm robotic system at the Queen's University of Belfast (QUB). The practical implementation of the system involves motion coordination of two multi-joint RTX robots with six degrees-of-freedom, interfaced through transputers to a host SPARC-IPC workstation. A path-planning scheme is introduced to provide accurate and coordinated collision-free motion. In addition, taking into account the need for high productivity in industrial environments, minimum-time movements are imposed by increasing the manipulators'performance to a maximum, thus providing a high-performance workcell. A real-time case study and its implementation is included to show the validity and efficiency of the system.
Modular system for control experimentation
Authors: Mitchell R.J.
Published: November 2007

A modular system has recently been developed which allows many experiments to be performed studying various control problems. Experimenters can use software provided for them which demonstrates the appropriate principles, as well as developing their own programs. The system is user friendly, allows the development of a variety of algorithms, and its modularity has enabled the system to be used in many applications both for teaching and research.

This paper describes the philosophy behind the system, the components used in its implementation and some of the ways in which it has been used. These include control of a motor, interfacing to microprocessors, analysis and control of a flexible arm, and measurement and control in a mobile robot.
Variable geometry exhaust gas system modelling
Authors: Bartlett H. , Whalley R. , Seale W.J.
Published: November 2007

Analytical procedures enabling the modelling of variable geometry exhaust gas systems are considered. An automotive application is investigated. Simulation results portraying the effect of step and pulsating increases in gas flow through a vehicle exhaust system are presented.
CAD supported design strategies for MIMO systems: illustrative solutions using a coupled tanks experiment
Authors: Fletcher I. , Wilson I. , Cox C.S.
Published: November 2007

A large number of design strategies exist for multivariable control situations. Many of' the methods require a linear time-invariant process characterisation in the form of a state space model or transfer function matrix description. Quite often this is not available and could be evpensive to realise. If this latter route is pursued there needs to be considerable benefits in the quality of the resulting closed-loop performance, especially when compared to those methods which only require minimal system information. The main aim of this paper is to compare a range of multivariable design strategies using a commercial multivariable coupled tank experimental rig as the uncompensated plant,
Application of an extended Kalman filter for high-performance current regulation of a vector-controlled induction machine drive
Authors: Hardan F. , Zhang L. , Shepherd W.
Published: November 2007

Variable frequency AC drives using voltage-source inverters to supply induction motors are increasingly used in industry for high-performance speed response. Such a drive usually employs a vector-controller at the outer speed-loop which will generate the required torque-current signal. An inner current control loop is incorporated to ensure that an appropriate reference current is impressed on the stator circuit. However, due to nonlinearity and time varying characteristics of the machine circuit, a fixed-parameter regulator cannot give good current control performance in the transient state.

The paper presents a model-based predictive current regulator for a vector-con trolled induction motor drive. An extended Kalman filter is employed to estimate the back-EMF of the machine stator circuit model used by the inner current regulator loop. This also estimates the rotor resistance for slip angular velocity calculation in the outer speed-loop. The adaptive feature of this controller leads to improved speed-response performance from the induction machine.
Optimum design of spherical retroreflectors with refractive indices close to 2.0
Authors: Webster C.A.G.
Published: November 2007

Spherical retroreflectors are customarily constructed of cemented hemispheres made from conventional glasses. With the recent availability of glass with a refractive index close to 2 the possibility exists of making such a reflector out of a simple sphere. A refractive index of exactly 2.0 is optimum for reflecting a beam of zero width. For finite beam widths, better overall performance is obtained with an index slightly less than 2.0.
Neural network identification and control of an underwater vehicle
Authors: Lisboa P.J.G. , Kodogiannis V.S. , Lucas J.
Published: November 2007

Real-time predictive control requires a forward model that is both accurate and fast. This paper introduces two nonlinear internal memory network architectures and compares their performance with a Multi-layer Perceptron (MLP) augmented with the use of spread encoding. The test plant is a single component from an Underwater Robotic Vehicle (URV), comprising a thruster encased in a steel frame and provided with buoyancy. This assemblv is free to move under water and is controlled for depth.

The internal memory networks are of comparable accuracy to the MLP but more parsimonious, resulting, in a faster response which makes them better suited for on-line control. Although a particular case study is presented as the focus of this paper, the algorithms and methods developed have generic applicability.
Modelling and control of fed-batch fermentation processes: towards improved quality and productivity
Authors: Zhang B.S. , Vanichsriratana W. , Tang R. , Porter N. , Leigh J.R.
Published: November 2007

This paper describes research into modelling, estimation and control of fed batch fermentation and an application to a large fermentation plant producing secondary metabolites. The problems are examined in a general sense from the viewpoints of both biological science and control engineering. Very extensive modelling and estimation work has been carried out. Only the most significant outcomes are reported here but references to the detailed research are given. Some of the research has resulted in the development of a novel advanced supervisory system- the Intelligent Process Management System (IPMS). Experience of applying the IPMS to a large-scale production process is described. The software has been designed on a modular basis and although implemented initially at one production plant, the approach is generic and fundamentally plant-independent so that further application to a range of other plants is envisaged.
A quantitative fault detection method for a class of nonlinear systems
Authors: Shields D.N. , Damy S.
Published: November 2007

This paper proposes an observer-based fault detection method for a class of nonlinear models which have bilinear and quadratic nonlinear terms in their discrete state-space representations. Various other methods proposed in the field are related to this method or are special cases of it. A nonlinear fault detection observer is proposed such that the error dynamics are independent of an unknown disturb ance. A result is proved for the observer error dynamics and a numerical algorithm is given for calculating the observer and residual gain matrices. Sufficient conditions are also stated for fault detectability. An illustrative example is given for the problem of detecting certain faults in a hydraulic system.
Intelligent monitoring and fault management for muscle relaxation anaesthesia
Authors: Linkens D.A. , Chen H.H.
Published: November 2007

Surgery on humans in hospital operating theatres represents a safety-critical environment which demands high standards of computer-based equipment used in these circumstances. This paper describes a detailed method ology for fault detection and localisation for the process of drug-induced muscle relaxation. The components in such an on-line management system are represented using a common framework based on bond graphs. Several examples are given of simulated system performance under typical problems of sensor interference, syringe pump failures and changes in patient's pharmacological state. Successful fault localisation and restoration pro cedures are demonstrated.
Design of a controller for a highly coupled V/STOL aircraft
Authors: Bennett D. , Burge S.E. , Bradshaw A.
Published: November 2007

This paper describes the design of a controller for a vertical/shart take-off and landing (V/STOL) aircraft using the Robust Inverse Dynamic Estimation (RIDE) control theory to improve aircraft performance and reduce pilot workload throughout the transition phase from jet to wing-borne flight and vice versa. The controller is required to be effective throughout the speed envelope from hover to 200 knots, during which the aircrafi undergoes significant changes in its dynamics characteristics. The design of the controller is based on a mathematical model of the aircraft linearised at 120 knots, is developed using realistic actuator and sensor models and is extended across the speed range, resulting in the transition envelope controller which is capable of providing acceptable pilot workloads and handling qualities throughout the transition phase. Controller design issues such as the choice of feedback variables, the selection of pilot inceptor configurations and functionalities, and the use of integrator anti-windup techniques in the presence of actuator saturation are discussed. Pilot-in-the-loop simulation studies show that the controller provides good control and handling qualities throughout the transition phase.
A Longitudinal Examination of the Bidirectional Links Between Academic Achievement and Parent–Adolescent Conflict
Authors: Dotterer Aryn M. , Hoffman Lesa , Crouter Ann C. , McHale Susan M.
Published: November 2007

We examined reciprocal associations between parent-adolescent conflict and academic achievement over a 2-year period. Participants were mothers, fathers, and adolescents from predominantly White, working and middle class families ( N = 168). After accounting for previous academic achievement, parent—adolescent conflict predicted relative declines in academic achievement 2 years later. After controlling for relationship quality at Time 1, lower math grades predicted relative increases in parent-adolescent conflict 2 years later among families with less education.
The epistemological status of second language acquisition
Authors: Schwartz Bonnie D.
Published: November 2007

In this paper I argue for the necessity of recognizing the epistemological basis of language (and hence of linguistic theory) for research in and theories of second language acquisition. In particular, I review the arguments for a generative approach to linguistic theory (e.g. Chomsky, 1965, 1975, 1981) and for why language as a system of knowledge must be distinct from other sorts of know ledge (Fodor, 1983), with the purpose of clarifying many misconceptions that seem to have arisen with respect to the work in generative grammar over the last 20 years. After doing this I argue that the null hypothesis for second language acquisition is, as concerns its mental representation of linguistic knowledge, that its epistemological status should be assumed to be the same as that of L 1 until proven otherwise. I then demonstrate how SLA theory (e.g. Krashen, 1981) can be elucidated by subsuming (parts of) L2 under linguistic theory with its firm epistemological basis, and how, in particular, one could empirically test Krashen's theory as well as any other theory of SLA that assumes L 1 and L2 to be epistemologically equivalent. In addition I discuss the need for researchers to consider the special epistemological status of linguistic knowledge before prescribing L2 pedagogy. In sum this is a paper that takes a step back into the philosophical debate concerning the mental status of language in general in order for us to be able to take a step forward in second language research in particular.
Prosodic structure in phonological acquisition
Authors: James Allan R.
Published: November 2007

This article discusses the acquisition of the prosodic characteristics of a second language in the light of the development of a target language phonological grammar. Prosodic characteristics are conventionally taken to refer to the intonation and accent patterns in a phonological system. However, nonlinear theories of phonology view the pitch and stress values of a language as defining a separate representation or component in a phonological grammar, i.e. the prosodic structure. A 'metrical' type model of prosodic structure is presented, in which the structural layers of a phonological hierarchy are characterized by the occurrence of particular contrastive (paradigmatic) features and particular phonetic (syntagmatic) effects at each unit-level. The course of acquisition of the prosodic structure of a second language is then shown to be describable in terms of the gradual development of target language values per unit-level of the hierarchy. Data from the L2 English of two L 1 Dutch speakers are examined by way of illustrating some of the claims of the model.
Directions of influence in first and second language acquisition research
Authors: Foster-Cohen Susan H.
Published: November 2007

This article explores ways in which studies in second language acquisition (SLA) research can illuminate first language acquisition research. The discussion revolves around the issues of learner strategies, individual variation, the acquisition of late learned structures, bilingualism, the role of Universal Grammar (UG) and the fate of obsolete knowledge in acquisition. It is argued that second language research in these (and other) areas can provide fresh insights into familiar problems and raise issues not commonly given consideration in first language acquisition studies.
Learning an alien lexicon : a teach-yourself case study
Authors: Jones Francis R.
Published: November 2007

This article uses diary data to examine a British learner's self-study experience of Hungarian, with reference to lexis. Though European in orthography and cultural background, Hungarian has no cognates and few borrowings from other European languages, enabling close focus on lexical acquisition strategies and processes per se. From this learner's experience, it is suggested that building a working lexicon is the single most important task facing the learner. In this there appear to be two key enabling aims: gaining a large enough stock of core lexemes to use etymological strategies on complex vocabulary, and developing the ability to read real texts. Reaching these thresholds is likely to be a hard task; beyond them learning may well become more enjoyable. A combination of studial and output-practice strategies is seen as crucial at all proficiency levels, however. Self-study coursebooks are also discussed; key factors identified are: leamability, reference value and the provision of personalized, message-based practice.
The hidden dangers of computer modelling: remarks on Sokolik and Smith's connectionist learning model of French gender
Authors: Carroll Susanne E.
Published: November 2007

Sokolik and Smith (1992) conducted three computer modelling experiments involving the learning of French gender attribution using a connectionist architecture. Their device learns to classify nouns quickly, given only letter-plus-position information about word spellings and feedback about the match between the target and the device's output. In particular, the device is not programmed with rules nor does it acquire any. Sokolik and Smith conclude that their model of gender attribution and the acquisition thereof has relevance for SLA. In these remarks, I show why this conclusion is wrong.
A brief history of processing approaches to SLA: reply to Mellow
Authors: Pienemann Manfred , Johnston Malcolm
Published: November 2007

In his article Mellow claims that the 'predictive model' is based on a transformational analysis of word formation. We will show that this is incorrect and that instead, the model is based on the psychological concept of exchange of linguistic information. Therefore, Mellow's evaluation of various types of transformational analyses is quite irrelevant for the model.

To demonstrate our point we will reproduce the full text of the original description of the 'predictive model'. We will show that the transformational connection should properly be traced to Clahsen's strategies which apply to syntax only. The strategies approach will then be described in contrast to the 'predictive model' in order to characterize the two approaches and their historical context. This will provide the background to a brief critique of the strategies approach. Theory formation in later processing approaches to SLA will then be sketched out briefly before addressing several points of detail in Mellow's article.