bluuebunny/crossref_metadata_2025 huggingface dataset:
An automatic low-level gas blender
Authors: Mohamad G.H.P. , Coles G.S.V. , Watson J.
Published: November 2007

The design and construction of a new automated low-level gas mixing apparatus is described which is intended for use in the testing and characterisation of solid-state and other gas sensors. This apparatus will blend gases such as carbon monoxide with clean air to produce mixtures of 1 to 1000 parts per million and is based upon the volume proportioning principle, where a gas sample is prepared by mixing a pre-determined volume of pure gas with a known volume of clean air. The instrument is capable of producing repeatable gas mixtures at a series of specified concentrations with accuracies better than ±0.5% for the low range (1-100 ppm) and ±0.2% for the high range (100-1000ppm) as compared with concentrations measured using two calibrated commercial monitors.
Manufacturing process modelling using object-oriented qualitative analysis methodology
Authors: Wright David T. , Williams David J.
Published: November 2007

This paper presents a novel real-time problem analysis methodology entitled the Object-Oriented Qualitative Analysis (OOQA), combining elements of Object Oriented (00) and Qualitative Analysis (QA) methodologies to aid the design of process models. Literature relating to the complexity of manufacturing processes and systems is reviewed in light of modern Computer Integrated Manufacturing (CIM) and software-based analysis approaches. The novel OOQA real-time manufacturing and business process analysis methodology is presented, based primarily on the Booch, and the Rumbaugh Object Modelling Technique (OMT) OO methodologies, and the QA approach of DeKleer. The real-time extensions enable complex process interrelationships to be captured. This methodology is demonstrated on the pultrusion composites manufacturing process, to assist identification of important process variables prior to numerical modelling. Introduction is made to the application of OOQA to bioprocess, and logistics supply chain case studies, and the use of OOQA analysis for Artificial Neural Network (ANN) modelling.
A sliding mode control approach to reduce the influence of manipulator disturbances on an underwater vehicle's position
Authors: Dunnigan Matthew W.
Published: November 2007

Manipulator movement produces force/moment disturbances which act on the underwater vehicle and alter its position, and consequently the manipulator end-effector position. The effect of the manipulator motion, assuming perfect manipulator joint angle tracking, on the vehicle's position and consequently the manipulator end-effector position is investigated assuming no vehicle control. Control of the vehicle's yaw angle, in this particular manipulator-vehicle configuration, has been determined to be the single most important factor in reducing the end-effector error variation. Due to the nonlinear dynamics of the vehicle, Slotine's sliding mode approach has been used. This technique allows the expressions developed for the manipulator disturbances to be incorporated in the control law. This is shown to be beneficial in the regulation of the vehicle's yaw angle, and offers improved performance compared with a sliding mode controller that does not incorporate the manipulator disturbances. This technique also demonstrates superior performance and insensitivity to parameter variations compared with a fixed-gain controller.
Matrix quadratic models with variable parameters
Authors: Whalley R.
Published: November 2007

Mechanical system and electrical circuit models represented by the matrix quadratic are considered. Parameter variations which may be due to modelling uncertainties or coefficient adjustments are incorporated. The characteristic-zero excursions induced by modelling changes are investigated. A typical application where the frictional dampers can be adjusted to provide efficient oscillatory regulation is outlined.
Using the Method of Referred Derivatives to simulate the dynamics of systems in vapour-liquid equilibrium
Authors: Thomas P.J.
Published: November 2007

Two-phase systems in vapour-liquid equilibrium are common features of chemical and power plant and have the characteristic that the vapour and liquid temperatures equalise very quickly compared with the response speed of the rest of the plant. It is normal for the control modeller to assume the equalisation process is instantaneous, which leads to a set of nonlinear simultaneous equations, making such systems candidates for the Method of Referred Derivatives. The paper describes how this technique provides a framework for calculating directly the evaporation or condensation rates needed to keep the two phases in equilibrium. The mass and temperature derivatives may then be found and integrated numerically in a straightforward time-marching manner to trace the transient behaviour of the system. The paper considers both single component and multicomponent boiling and condensing, and, in an appendix, offers advice on suitable forms of thermodynamic functions for use with the method.
Computed torque control applied to a simulated two-flexible-link robot
Authors: Morris A.S. , Madani A.
Published: November 2007

This paper addresses the problem of controlling a two-flexible-link manipulator. The idea of industrial manipulators having some lightweight, flexible links is attractive if high-speed motion is required in manufacturing operations because they avoid the severe control problems associated with the large inertia forces generated when the large-mass rigid links in conventional robot manipulators move at high speed. In the commonest form of industrial robot, the six-degrees-of-freedom (6DOF) revolute-geometry type, only two of the links (the upper and lower arm) are subjected to significant inertia forces and therefore only these two links need to be lightweight and flexible. A two-flexible-link system controller is an appropriate starting point for dealing with such a 6DOF robot, because this can be readily expanded by adding simple controllers for the other rigid links. A modified computed torque algorithm is shown by simulation with MATLAB to control satisfactorily the oscillatory tendency of the two-flexible-link system.
Tuning fuzzy ship autopilots using artificial neural networks
Authors: Sutton R. , Roberts G.N. , Taylor S.D.H.
Published: November 2007

This paper is concerned with an investigation into the use of artificial neural networks in the design of fuzzy autopilots for controlling the non-linear yaw dynamics of a modern Royal Navy warship model. Artificial neural networks are used to tune the consequent portion of the fuzzy conditional statements which constitute the fuzzy autopilots and comparisons are made between several training algorithms and two different network structures. Results are presented to show the viability of such an approach and that effective designs can be produced.
A sensor fault accommodation system using a neural network
Authors: McLean D. , Saade C. , Zinsch F.
Published: November 2007

The presence of faults on feedback sensors can have serious effects on the performance of closed-loop systems. This note describes a method of using an auxiliary neural network controller to proviele the required closed-loop dynamic response even when sensorfaults are present. The effectiveness of the scheme is described in relation to a helicopter flight control system which operated with a variety of different types of sensor faults.
Nonlinear PLS using Radial Basis Functions
Authors: Wilson D.J.H. , Irwin G.W. , Lightbody G.
Published: November 2007

A new approach to nonlinear Projection to Latent Structures (PLS) modelling using Radial Basis Function (RBF) neural networks to provide a nonlinear inner relationship is described, along with a hybrid optimisation technique for training the networks. Results are given showing an improvement in modelling performance over linear PLS for a variety of problems. An application of the technique to fault detection on a validated model of an industrial distillation plant is also demonstrated.
Optimal control of a fed-batch fermentation process
Authors: Vanichsriratana W. , Zhang B.S. , Leigh J.R.
Published: November 2007

Optimisation of fed-batch fermentation processes usually employs the calculus of variations to determine optimal feed-rate profiles that will maximise a given objective function. This results in a two-point boundary-value problem and because of the nonlinear nature of the pro cesses, the optimal solution usually falls out as an open-loop control algorithm. One advantage of this approach is that it does not need measurements of state variables which are often difficult to obtain on-line. Instead it assumes that the state variables are proceeding along known paths a-priori determined by models. However, the disadvantage of such an approach is that the performance will severely deteriorate in the presence of process disturbances or plant-model mismatch. Recently, on-line estimation of state variables has been successfully developed and used in the industry and therefore a method which operates the fed-batch fermentation in a closed-loop control scheme using state feedback is proposed. This is achieved by a two-step method. First, the optimal substrate concentration profile which governs the biochemical reactions in the fermentation process is determined. Then a controller is designed in closed-loop form to track this desired profile. Simulation studies for both primary and secondary metabolite production processes show that better performance is obtained by this closed-loop aptifaaal control method than by the open- loop optimal feed rate profile method. This is due to the self-correcting property of the proposed method, which proves to be advantageous when there are disturbances or plant-model mismatch.
On-line application of an auto-tuning PI D controller for dissolved oxygen concentration in a fermentation process
Authors: Jones K.O. , Williams D. , Montgomery P.A.
Published: November 2007

Biotechnological processes are notoriously difficult to control because of their non-linear time-variant characteristics. The application of an autotuning PID controller is presented as a viable aid as either a means to determine suitable tuning PID parameter values or as a retuning controller, initiated either automatically or by an operator. The controller operation is introduced and on-line results presented to compare the performance of the autotuner with a well-tuned PID controller on both batch and fed-batch fermentations. The benefits for the operator and process operation are demonstrated with on-line results on batch anti fed-batch fermentation processes.
Non-linear model-based predictive control of gasoline engine air-fuel ratio
Authors: Lennox B. , Montague G.A. , Frith A.M. , Beaumont A.J.
Published: November 2007

Control developments allowing accurate regulation of air-fuel ratio in gasoline engines are critical if legislative emissions levels are to be adhered to early in the next century. However, the task is far from straightforward with severe non-linearities and long/variable dead times challenging even the most sophisticated control algorithms. The availability of accurate models of the system can aid in overcoming these hurdles. Neural networks offer one modelling approach which enables rapid and accurate model formulation from system performance data. Whilst neural network models may provide the required accuracy, they do not easily fit within a control framework, particularly when there is a requirement for a rapid sampling frequency. This paper shows how a neural network model may be built and incorporated within a model predictive control framework and, with some approximations, may be implemented on a system requiring frequent sampling. Application to a simulation of a sophisticated car engine serves to demonstrate the potential of the approach.
Model-based fault diagnosis of a two-pump system
Authors: Dalton Tracy , Patton Ron
Published: November 2007

This paper outlines the design and initial testing of a quantitative model-based fault detection and isolation (FDI) scheme for a water pumping system. The work has been motivated by the desire to develop a fault diagnosis and condition monitoring scheme for an industrial cooling water pumping system in operation at the 'Heysham 2' power station (British Energy). Methods of residual (fault indicator) generation using observers and parameter estimation are appraised as to their suitability for industrial systems, where sensor availability and limited sampling rates must be taken into considera tion. A detailed model of the industrial pumping system has been developed and the performance of the methods considered is illustrated using this model. Due to the industrial motivation the task of analysing the information provided by complementary methods is described and a practical scheme for the cooling system is proposed which considers the currently available methods and the particular challenges presented by the actual system.
Analysis of pulse width modulated systems and their saturated modes of oscillation
Authors: Barry Noel
Published: November 2007

The paper studies the modes of oscillations in control systems which employ pulse width modulation power dispatch techniques in their loops for a wide class of linear time invariant systems. Particular care is taken of the mode of oscillation under which instability can occur. Both bipolar and unipolar pulse width modulation is considered and conditions which produce chaotic behaviour in the plant response are investigated.
Power plant air/fuel ratio optimisation
Authors: Li N. , Thompson S.
Published: November 2007

It is argued that power plant air/fuel ratio is one of the more important parameters in achieving improved combus tion efficiency and reducing pollutant emissions. However, for most power plant the air/fuel ratio is fixed. This paper presents a feasibility study, based on operational data, which demonstrates how these gains may be realised by changing the air/fuel ratio set-point value. This is achieved by using a neural network to model an optimisation process satisfying pre-defined efficiency and emission require ments. The initial results are encouraging.
Using limit cycle data for parameter estimation
Authors: Kaya I. , Atherton D.P.
Published: November 2007

Exact expressions for the periods and amplitudes of limit cycles in relay controlled loops, with first order plus dead time (FOPDT) and second order plus dead time (SOPDT) transfer functions have been obtained using the A-locus method. The method has also been extended to unstable FOPDT and SOPDT transfer functions since it is possible to have unstable transfer function models for some chemical processes. For these processes, it is shown that analysis using the DF method can give large errors. Several examples have been given to illustrate application of the method and it has been shown that the method will work well for small measurement errors when compared with the DF method.
Active fault-tolerant flight control systems design using the linear matrix inequality method
Authors: Chen J. , Patton R.J. , Chen Z.
Published: November 2007

This paper discusses the issues of robust control law design for fault-tolerant systems. Based on the assumption that the effects of faults can be expressed in linear-fractional-transformation (LFT) forms, a fault-tolerant control systems design problem is formulated and solved via a linear matrix inequality (LMI)-based synthesis approach. In order to recover the convexity of the design problem whilst considering the robust performance and robust stability against faults and uncertainties simultaneously, a constrained optimisation approach is used. The simulation results of a design example (a longitudinal motion flight control problem for an unmanned aircraft in the case of suffering battle damage on its wing ) show that robust stability and satisfactory performance have been achieved.
Stabilization of longitudinal motion of a hypersonic transport aircraft
Authors: McLean D. , Zaludin Z.A.
Published: November 2007

Hypersonic transport (HST) aircraft are the subject of much current research as the need to reduce block times on long haul flights becomes more pressing. The dynamics of such HST aircraft are strongly influenced by the close interdependence of the aerodynamic and propulsion systems. The key dynamic features of such aircraft are their dynamically unstable longitudinal motion, and extremely sluggish response in pitch attitude, which make aircraft of this type difficult to fly. This paper presents the design of an automatic flight control system which can provide the required degree of stability and the required flying qualities. The optimal feedback control law was derived from the use of linear quadratic regulator (LQR) theory, in which the state weighting matrix was calculated from known closed-loop eigenvalues which were specified by the designer to obtain the required stability and flying qualities. The effectiveness of the multivariable control law is illustrated by means of dynamic responses obtained from a simulation based upon an HST aircraft flying at Mach 8.0 at a height of 85 000 feet.
The application of actuator performance limits to aeroservoelastic compensation
Authors: Taylor Richard , Pratt Roger W. , Caldwell Brian D.
Published: November 2007

An interaction between an aircraft's structural dynamics, unsteady aerodynamics and flight control system can have serious effects on the aircraft both in terms of structural integrity and rigid body stability. The effects of such an interaction, known as aeroservoelasticity, are poorly understood and as a result, very conservative flight control system design methods are used in order to achieve flight clearance. This paper demonstrates how the use of nonlinear actuation system models predicts a maximum boundary for the amplitude of the structural response as a result of the performance limits of the nonlinear actuation system. This envelope of maximum structural response can then be used to allow relaxation of the current design criteria for the structural mode filters. The procedure is demonstrated using a representative aircraft system model. Finally, the results of single input frequency response tests of a representative actuation system are presented in support of the earlier results.
Multivariable control analysis of a hydraulic turbine
Authors: Jones D.I.
Published: November 2007

Dinorwig is a pumped storage hydroelectric power generation station which is used for frequency regulation on the national grid. Its control system consists of separate PID governors for each of the six 300 MW turbine-generators. Accuracy and speed of response in counteracting supply frequency disturbances is improved by increasing the PID gains but recent experience has shown that this can sometimes lead to oscillatory behaviour. At Dinorwig, water is supplied to the turbines by means of a common tunnel from the upper lake which is then split by a manifold into six separate penstocks for individual machines. This paper uses a linearised multivariable model of two machines, coupled through a non-elastic water column, to show that this reduces the system's stability margin and that PID parameters tuned for optimum single machine operation are not suitable when two (or more) machines are in use. The Direct Nyquist Array method is then used to design a control system, consisting of a decoupling compensator and conventional PID controllers, which reduces the interaction between the two machines. The results show that some reduction in the speed of response must be accepted during multi-machine operation but that, whilst the multivariate controller is more complex to implement than the current individual governors, it yields a better stability margin and reduces interaction between machines.
Human-machine systems
Authors: Wieringa Peter A. , Stassen Henk G.
Published: November 2007

A brief overview of theoretical, experimental and industrial issues that are typical for studies on human-machine systems is given. The paper distinguishes three human-machine interaction modes: direct control, intermittent control and supervisory control. It is shown that a technology-driven engineering approach drives human-machine interaction out of the loop. It is challenging to use developments, such as multimedia, for all control modes, to enhance rather than abolish human-machine interaction. Design of any of the control modes requires a human-centred design approach. This overview refers to other papers in a series dedicated to human-machine systems.
Plant modelling for human supervisory control
Authors: Lind Morten
Published: November 2007

This paper provides an overview of multilevel flow modelling (MFM) and its application for design of displays for the supervisory control of industrial plant. The problem of designing the inforrrzatian content of sacpervisory displays is discussed and plant representations like MFM using levels of means-end and part-whole. abstractions are proposed as a solution to this design problem. The basic concepts of MFM are explained and its use in reasoning about means and ends, and part and whole in diagnosis are illustrated in detail by way of an example. A deeper elaboration of the semantics of MFM is also provided by an analysis of the relations between levels of abstraction. It is also described how MFM supparts reazsonin about control actions by defining levels of intervention and by modal distinctions between function enablement and initiation.
The availability of universal grammar to adult and child learners - a study of the acquisition of German word order
Authors: Clahsen Harald , Muysken Pieter
Published: November 2007

Children learning German as their first language grasp its verb-final character from the very beginning. Adults learning German as a second language tend to assume in the beginning that it has a subject-verb-object order, and modify this hypothesis only gradually. We argue that this difference is due to the fact that children have access to the 'move alpha' matrix when learning the language, allowing them to make more abstract hypotheses, while adults can only rely on general learning strategies.
The current convergence in linguistic theory: some implications for second language acquisition research
Authors: Newmeyer Frederick J.
Published: November 2007

To the outsider, generative grammar must appear to contain a bewildering variety of different frameworks for syntactic description, each with its own distinct goals, research programme and technical vocabulary. It seems fair to say that this seeming inability of theoretical linguists to get their own house in order has led many applied linguists to question whether even the most general conceptions of generative grammar have any relevance to their concerns. Despite superficial appearances, however, the differences between the major generative frameworks are relatively minor, and are steadily lessening. Indeed, a convergence is taking place among the three most important, namely, the government-binding theory, generalized phrase structure grammar, and lexical-functional grammar. In particular, all now accept two basic concepts governing grammatical processes: 'modularity' and 'locality'. According to the former, grammatical complexity results from the interaction of autonomous grammatical subsystems; according to the latter, grammatical processes are sharply constrained as to the degree of 'distance' that the elements involved may lie from each other. It will be argued that these convergences have interesting implications for those who wish to apply linguistic theory to the understanding of second language acquisition.
UG or not UG, that is the question: a reply to Clahsen and Muysken
Authors: duPlessis Jean , Solin Doreen , Travis Lisa , White Lydia
Published: November 2007

In a recent paper, Clahsen and Muysken (1986) argue that adult second lan guage (L2) learners no longer have access to Universal Grammar (UG) and acquire the L2 by means of learning strategies and ad hoc rules. They use evidence from adult L2 acquisition of German word order to argue that the rules that adults use are not natural language rules. In this paper, we argue that this is not the case. We explain properties of Germanic word order in terms of three parameters (to do with head position, proper government and adjunc tion). We reanalyse Clahsen and Muysken's data in terms of these parameters and show that the stages that adult learners go through, the errors that they make and the rules that they adopt are perfectly consistent with a UG incor porating such parameters. We suggest that errors are the result of some of the parameters being set inappropriately for German. The settings chosen are nevertheless those of existing natural languages. We also discuss additional data, from our own research on the acquisition of German and Afrikaans, which support our analysis of adult L2 acquisition of Germanic languages.
The effects of script on visual search
Authors: Green David , Meara Paul
Published: November 2007

Native English speakers search short strings of letters differently from the way they search strings of nonalphanumeric symbols. Experiment 1 demonstrates the same contrast for native Spanish speakers. Letter search, therefore, is not a result of the peculiarities of English orthography. Since visual search is sensitive to the nature of the symbols being processed, different scripts should produce different effects. Experiments 2 and 3 confirmed such differences for Arabic and Chinese scripts. Furthermore, these experiments showed no evidence that native Arabic and native Chinese speakers adapt their search strategy when dealing with letters. Implications of these findings are considered.
Influences of bilingualism on metalinguistic development
Authors: Bialystok Ellen
Published: November 2007

The relationship between metalinguistic awareness and bilingualism is interpreted in terms of a framework which defines metalinguistic awareness as consisting of two processing components: analysis of linguistic knowledge, and control of linguistic processes. It is argued that bilingualism enhances only the latter of these processing components, so global assessments of metalinguistic ability by bilingual subjects are bound to lead to inconsistent results. Some studies are reported in which these two processing components are separated. Bilingual children are shown to be superior to monolingual children on measures of control of linguistic processes.
Linguistic universals, markedness and learnability: comparing two different approaches
Authors: White Lydia
Published: November 2007

There are currently two different linguistically-based approaches to universals in second language acquisition, one stemming from typological universals (Greenberg, 1966) and the other from Chomskyan Universal Grammar. Associated with each approach is a concept of markedness. Typologists define markedness implicationally; current theories of language learnability define markedness in terms of the Subset Principle. Although coming from very different perspectives, these two definitions of markedness coincide in a number of predictions they make for L1 and L2 acquisition. Similarities and differences between these two approaches to markedness and acquisition are discussed in this paper.
Monitoring in children's second language speech
Authors: Verhoeven Ludo T.
Published: November 2007

The present study investigates the monitoring behaviour of Turkish children speaking Dutch as a second language. Spontaneous speech data were collected over a period of two years at one-year intervals with 74 children from the time they entered Dutch primary schools. In order to discover developmental changes, a typology of monitoring behaviour was given as a function of the children's age. A distinction was made between corrections, restarts and repeats. With regard to corrections, phonological, syntactic and semantic types were distinguished. In order to explain the individual variation in monitoring, the occurrence of monitoring types was correlated with nonverbal cognitive skill and with oral second language proficiency. The structure of monitoring processes was investigated by determining the point in the utterance at which children go back to make a new start for correction, after they have detected an error. The results show that during the process of second language acquisition different types of repairs can be distinguished, some of which increase with age and some of which decrease. A positive relationship was found between monitoring use and the child's cognitive skill and second language proficiency. With regard to the structure of monitoring, it was found that phonological errors tend to be detected faster than syntactic and semantic errors. The results are dicussed in the light of research on first language monitoring use.
Parameter setting in second language phonology and syntax
Authors: Broselow Ellen , Finer Daniel
Published: November 2007

This paper reports on studies of second language acquisition in two domains, phonology and syntax. The phenomena investigated were the acquisition by native speakers of Hindi, Japanese, and Korean of two areas of English: in phonology, the mastery of particular syllable onset clusters, and in syntax, the acquisition of the binding patterns of reflexive anaphors. Both these areas are ones for which multi-valued parameters have been posited to account for the range of variation across natural languages. The paper presents evidence that acquisition in these two areas is quite similar: at a certain stage of acquisition learners seem to arrive at a parameter setting that is midway between the native and the target language settings. This effect occurs both when the target language employs a less marked setting than the native language and when the target language setting is more marked than that of the native language.
Corrective feedback in historical perspective
Authors: Schachter Jacquelyn
Published: November 2007

In this paper, pedagogical, linguistic theoretical, and psychological perspec tives on corrective feedback are discussed and an attempt is made to inte grate these different perspectives. To a large extent, researchers in these three approaches have been isolated from one another, each ignorant of the others' stands on the issues. Herein, we attempt to overcome the isolation, interweaving the similarities and pointing out the differences of the three approaches.

It is argued that the answers to questions raised here and elsewhere concerning the role of corrective feedback in language learning will not come in the form of sweeping affirmative or negative generalizations. They will come from the careful teasing apart of the components of language and experimental work on these components. We need to ascertain whether some components can in fact be acquired on the basis of positive evidence alone, and whether negative evidence (feedback) is required for successful mastery of some other components.
Speaking to many minds: on the relevance of different types of language information for the L2 learner
Authors: Smith Michael Sharwood
Published: November 2007

This paper re-analyses the notion of consciousness raising in language learning. The process by which language input becomes salient to the learner is termed 'input enhancement'. This process can come about as a result of deliberate manipulation, or it can be the natural outcome of some internal learning strategy. It can vary quantitatively and qualitatively, not necessarily involv ing conscious analysis of rules. Externally induced salience may not neces sarily be registered by the learner and even when it is registered, it may not affect the learning mechanisms per se. Certain inferences are made about the interpretation of learner performance and ways of measuring it.
Recognizing numbers in different scripts
Authors: Randall Mick
Published: November 2007

This paper considers the effects of different language scripts on the recognition of digits. It reports on two experiments with Arabic-speaking subjects in which they were asked to scan arrays of digits in both standard 'Western numeral' and 'Indian numeral' forms. It compares the array-scanning patterns observed with patterns observed with speakers of other languages, in particular with English native speakers. It discusses the implications of these findings in terms of the use of language-specific word recognition strategies.
Well-formed vs. ill-formed strings in L2 metalingual tasks: specifying features of grammaticality judgements
Authors: Hedgcock John
Published: November 2007

The use of metalingual tasks in L2 acquisition research has recently been challenged by a number of critics on the grounds that they may constitute only an indirect and unreliable reflection of learner competence. Recent research involving metalingual judgements tests has revealed that learners' reactions to well-formed and ill-formed strings emerge largely as a result of the cognitive processes brought about by the particular characteristics of the linguistic stimulus. Moreover, the assumption that learner judgements tap into a unitary or stable knowledge source has been called into question, since a number of knowledge systems and levels of awareness have been found to contribute to learner performance in L2. Because disagreement continues about the usefulness of metalingual judgements and the information they can provide, this article aims to clarify currently established perspectives on this issue, particularly with respect to the question of how learners' tolerance of ill-formedness compares to their acceptance of well-formedness. It will be argued that specific aspects of the form and content of grammatical and ungrammatical test strings may strongly influence the saliency of certain malformations, and impact the decision-making process in systematic ways.
The status of CP and the tensed complementizer that in the developing L2 grammars of English
Authors: Lakshmanan Usha , Selinker Larry
Published: November 2007

In this article we examine the development of the complementizer system in child L2 grammars of English, and we show that C and its maximal projection CP are operative from the very beginning. Next, we focus on the development of the tensed complementizer that. We provide evidence which suggests that the tensed complementizer in embedded declaratives may be treated as an obligatorily null complementizer by these child L2 learners. We then examine restrictive relative clauses produced by our subjects. The evidence indicates that the tensed complementizer is first realized overtly as that in the relative clause domain. We speculate on the possible reasons as to why the relative clause domain should trigger the emergence of the overt tensed complementizer and we argue that recent proposals by Rizzi (1990) for a typology of complementizer types enable us to account for these child L2 developmental facts.
On positive evidence and ultimate attainment in L2 phonology
Authors: Young-Scholten Martha
Published: November 2007

Since the early 1970s, L2 syntax researchers have seriously challenged the applicability of a critical period to the acquisition of L2 syntax, reformulating this challenge in the 1990s in terms of whether postpuberty learners retain access to the principles and parameters of Universal Grammar (UG). While it seems much more likely that a critical period applies to the postpuberty acquisition of a second phonology, research in the last several decades indi cates that adult learners do have access to the phonological principles and parameters of UG. Recent work on the nature of the input required to accomplish the setting of parameters in syntax offers one possible explana tion for lack of native-like attainment in L2 phonology.
A formal model of learning L2 prosodic phonology
Authors: Archibald John
Published: November 2007

In this article I discuss the various components necessary for a formal model of the acquisition of the prosodic phonology of a second language. I outline a model that includes an explicit theory of the representation of metrical knowledge (Dresher and Kaye, 1990; Idsardi, 1992) and the necessary learn ing theory to account for how those representations can be acquired. The learning theory which mediates the interaction between Universal Grammar (UG) and the linguistic environment is composed of such elements as appro priate cues, indirect negative evidence and a principle of lexical dependency.

Empirical investigations of the acquisition of English metrical parameters by native speakers of Polish, Hungarian and Spanish are reported. Group data as well as case studies are presented. The data suggest that, in the domain of prosodic phonology, both the representations (metrical structure) and processes (learning principles) evidenced in second language learners are the same as those proposed for native speakers. Interlanguage grammars can be seen as a combination of UG principles, correct L2 parameter set tings (from resetting) and incorrect L1 parameter settings (from L1 trans fer).
L2 acquisition of English synthetic compounding is not constrained by level-ordering (and neither, probably, is L1 )
Authors: Lardiere Donna
Published: November 2007

This article investigates the acquisition of English synthetic compounding by native Spanish and native Chinese speakers. Data are presented which con tradict the claim by Gordon (1985), Clahsen (1991) and Clahsen et al. (1992) that morphological level-ordering is universally, innately available to lan guage learners to guide their acquisition of compounding constraints. Empirical arguments are given which show that compounding, at least, can not be universally subject to the particular inflectional constraints - namely, a restriction on plurals in compounds - imposed by the level-ordering mod els cited in the above acquisition studies. I also present additional experi mental results which demonstrate that L2 learners of English freely violate this restriction, and that such violations reflect particular L1 influence.

I suggest an alternative approach to analysing the role of Universal Grammar in the acquisition of compounding which better accounts for both the L1 and L2 English data, by considering 1) the interaction of syntactic principles with lexical derivation; 2) the parametric differences between the L1 and L2; and 3) the language-specific nature of morphological affixation.
Acquisition of the Japanese reflexive zibun and movement of anaphors in Logical Form
Authors: Thomas Margaret
Published: November 2007

Several recent accounts of crosslinguistic variation in the properties of anaphors have rejected Manzini and Wexler's (1987) parameterized binding principles. Pica (1987), Battistella (1989), Cole et al. (1990) and Katada (1991), among others, claim that anaphors move in Logical Form (LF) such that 'long-distance' binding can be reduced to a series of local relationships. This article looks at research on adult second language learning in the light of the proposal that reflexives move in LF. A first approach to the issue reanalyses data from earlier research on the acquisition of the Japanese long-distance anaphor zibun, research conducted under the assumption that the binding principles are parameterized. Secondly, a new study of 58 adult learners of Japanese is presented, showing that learners' knowledge of zibun at a high-proficiency level is largely consistent with a key prediction of the movement in LF approach. Although relatively few high-proficiency learners in the subject pool seem to have arrived at the full native-speaker grammar of zibun, there is little evidence that the grammars they construct violate principles of Universal Grammar. On the other hand, data from lower-proficiency learners are less readily accounted for from the perspective of movement in LF.
Gradual development of L2 phrase structure
Authors: Vainikka Anne , Young-Scholten Martha
Published: November 2007

We begin by reviewing data from Korean, Turkish, Italian and Spanish-speaking adults acquiring German without formal instruction. Our findings have shown that these learners transfer their L1 VPs: the Korean and Turkish speakers transfer a head-final VP and the Italian and Spanish speakers first transfer a head-initial VP and then switch its headedness to the correct, head-final value for German. Although functional projections in Korean and Turkish are head-final and in Italian and Spanish head-initial, all four groups of learners subsequently posit head-initial functional projections in German (which are not always target-like). We conclude that only lexical projections constitute the L2 learner's initial state; the development of functional projections is driven solely by the interaction of X'-Theory with the target-language input.

We then discuss some studies on the acquisition of French by English speakers and of English by speakers of various L1s which purport to bring evidence to bear against our approach. Upon closer examination, the evidence turns out to offer further support for the position that the sole projections which the learner transfers from the L1 are lexical ones. Finally, we account for potentially problematic verb-raising data from French learners of English. Rather than taking the stance that French raising to Agr is transferred, we propose that L2 learners' identification of free morphemes as salient triggers leads to a misanalysis of verb raising in English. We also apply this idea to a reanalysis of the morpheme-order studies of the 1970s.
Nativism does not equal Universal Grammar
Authors: Wolfe-Quintero Kate
Published: November 2007

This article is about nativist theories of language learning and how they apply to SLA. I am seeking a nativism that goes beyond the scope of Universal Grammar (UG), that explains the human cognitive capacity for language learning (language knowledge, learning, and processing), the learning of all language structures found in natural languages (both core and peripheral), and SLA (learnability, development, transfer, and differential success). Such a theory does not yet exist, but current nativist theories (linguistic, developmental, general and connectionist) suggest ways in which such a theory might be developed.
On evaluating arguments for special nativism in second language acquisition theory
Authors: Eckman Fred R.
Published: November 2007

This article attempts to evaluate several arguments that have been put forth in favour of special nativism in SLA. Specifically, the cases for each of the following claims are considered: 1) that Universal Grammar (UG) being implicated in L2 acquisition is the null hypothesis; 2) that any theory of SLA necessarily needs a theory of grammar; and 3) that showing that interlanguage grammars are underdetermined by the available input implies that UG must be accessible in L2 learning. In each case, it is argued that the arguments for special nativism are not compelling, and that it is therefore reasonable to consider a research programme in SLA theory that is based on general nativism.
Automatic regulation of the cardiopulmonary bypass
Authors: Wada Juro , Hino Tsunekazu , Kaizuka Hideki , Ade Wolfgang R
Published: November 2007

We devised a new method and system for the automatic regulation of cardiopulmonary bypass. The system is planned so that it is regulated according to the alteration of venous pressure which is a reflection of venous return in total cardiopulmonary bypass. After many experimental studies, we have used this system in four clinical cases of cardiac surgery.

The system functioned sufficiently well in the clinical cases. Under the control of this system, the central venous pressure was kept at a preset level and changed cyclically in the same manner as the respiratory change through the entire cardiopulmonary bypass period. A constant and adequate venous return through the entire cardiopulmonary bypass period was assumed to be the most important factor for the venous return-triggered pump oxygenator.
Prevention of major perioperative neurological dysfunction—a personal perspective
Authors: Utley Joe R , Stephens D Barton
Published: November 2007

Neurological dysfunction following cardiac surgical procedures has many causes. We have reduced perioperative neurological dysfunction to very low levels with protocols related to five potential causes of perioperative stroke. The five areas we have concentrated upon are: 1) components and use of the heart-lung machine; 2) air embolization; 3) intrinsic cerebrovascular disease; 4) atheroemboli from the ascending aorta and; 5) clot emboli from the left ventricle. We have employed methods of operation of the heart-lung machine which minimize the risk of microemboli or air emboli. Air evacuation manoeuvres are employed in every patient at the termination of cardiopulmonary bypass. A brain protection protocol which employs pharmacological brain protection, as well as increased oxygen-carrying capacity and perfusion pressure, is used in patients with cerebrovascular disease and patients with atheromatous ascending aorta. Applying these protocols, we have performed 690 consecutive cardiac surgical procedures with strokes occurring in three patients (0-4%). There was one stroke in 558 patients (0.2%) having coronary artery bypass grafting. Stroke occurred in one of 48 high risk patients (2%) in whom the brain protection protocol was used. There were no apparent episodes of air embolization or embolization of clot from the left ventricle.
Review article : Current status and use of artificial hearts and circulatory assist devices
Authors: Unger Felix
Published: November 2007

In a critical review, current status of artificial hearts and cardiac assist devices is discussed, based on 300000 clinical implantations of intra-aortic balloon pumps, 278 clinical cases of ventricular assist devices and 17 total artificial heart implants.

It is justified to implant mechanical hearts as a bridge towards transplantation. Mechanical cardiac assistance has become almost a routine for teams dealing with cardiac transplantation.
Heparin-enhanced ADP-induced platelet aggregation in patients undergoing cardiopulmonary bypass surgery
Authors: Abela M. , McArdle B. , Qureshi M. , Pearson DT
Published: November 2007

Heparin has been shown to enhance ADP-induced platelet aggregation in patients undergoing cardiopulmonary bypass surgery. This effect appears to be maximal throughout the initial 30 minutes of systemic heparinization and once reached is maintained throughout the bypass procedure. The prebypass state is regained following heparin reversal by protamine sulphate. It is possible that this effect of heparin on platelet function may contribute towards some of the platelet microembolization phenomena seen in patients following cardiopulmonary bypass surgery.
Postbypass plasma surface tension and its role in bubble filtration
Authors: Butler BD , Kurusz M. , Conti VR
Published: November 2007

Plasma samples from patients undergoing open-heart surgery were obtained at the end of cardiopulmonary bypass for surface tension analysis. The samples were measured with a Du Nouy tensiometer for true static surface tension. The surface tension values from 40 patients were analysed and correlated with plasma free haemoglobin levels, cardiopulmonary bypass time and oxygenator type. The mean surface tension value for the plasma samples was 49·96 ± 2·98 dynes/cm. No statistical correlation was found between the surface tension and the three variables. Surface tension phenomena have important implications in the removal of gaseous microemboli by screen filtration of arterial blood as it is applied to the bubble point concept. Another aspect of surface tension involves the concept of capillarity which considers the forces tending to push a bubble through a blood vessel thus preventing the obstruction of blood flow. The results of this study provide actual values of plasma surface tension from patients undergoing cardiopulmonary bypass.