bluuebunny/crossref_metadata_2025 huggingface dataset:
End user issues for computer assisted surgical systems
Authors: Mohsen A.M.M.A. , Sherman K.P. , Cain T.J. , Karpinski M.R.K. , Howell F.R. , Phillips R. , Viant W.J. , Griffiths J.G. , Dyer K.D.F.
Published: November 2007

Orthopaedic implants are manufactured to the highest degree of precision by some of the most precise machines known to man and inserted into patients by some of the most imprecise methods known. Computer assisted systems aim to overcome this dichotomy by improving the planning and implementation of orthopaedic surgery. This can be achieved by providing the surgeon with better information for planning and a more precise means of implementing the surgery.

This surgical advancement will change current orthopaedic practice significantly if the appropriate surgical issues are considered during their development. Safety is obviously paramount and is being addressed, as is registration between the real (patient) and the virtual computer world.

The more subtle, but nevertheless important, surgical issues have as yet not been fully identified or addressed satisfactorily. The following questions serve to highlight them. Is there an optimal system size, shape, reach, control and positioning in surgery? What are the salient environmental and functional requirements ? Can there be intra-operative computer processing time? How important and what does timelessness, universality, communality and simplicity of the system mean? Should there be a relationship between training, surgical feedback and simplicity? What is partial or total sterilisation ? Can capital outlay and running costs for the system be reduced or avoided by the hospitals? Are computer assisted orthopaedic surgical systems cost effective, necessary, desirable or indeed indicated in current cost containment in the NHS?

The above questions are answered in this paper and points which are conducive to a positive response from the end user (surgeons, and hospital management) are discussed.
Sensor-based modification of manipulator trajectories for applications in rehabilitation robotics
Authors: McEachern W.A. , Dallaway J.L. , Jackson R.D.
Published: November 2007

This paper presents a strategy for the use of sensor information in a general purpose teleoperation system for rehabilitation. Current research in teleoperation and mobile robotics is reviewed and its relationship to the design of a rehabilitation manipulation system is discussed. Human models of reaching and grasping tasks are used as the basis for the development of sensor-based strategies for interaction with the environment. Integration of the strategies with the Cambridge University Robot Language is discussed, and quantitative results of experimental trials are presented.
Control using self-validating sensors
Authors: Yang J.C.-Y. , Clarke D.W.
Published: November 2007

The correct funetioraing of sensors is of paramount importance to the operation of industrial processes. The concept of a self-validating (SEVA) sensor, capable of detecting and correcting for its own faults and accompanying each measurement with an estimate of its uncertainty and standard quality indicators, has been proposed. This paper aims to investigate how the extra information provided by SEVA sensors can be used to enhance the performance of simple three-term (PID) controllers in the single-loop configuration. An implementation of the SEVA interface on a dissolved oxygen sensor and the device response to a common fault is described. SEVA sensor measurement quality indicators can be used to decide whether to continue closed-loop operation and, if so, how the controller should be retuned to counteract the of sensor faults: control strategies in the presence of a range of sensor malfunctions are illustrated by simulation examples.
Applying dynamic matrix control in the process industries
Authors: Austin P.C. , Bozin A.S.
Published: November 2007

Advanced multivairiable control system designs had little impact in the process industries until the development of model-based predictive control (MBPC) systems. This paper records some aspects of the application of one particular MBPC technique, Dynamic Matrix Control (DMC), to three different plants in the process industries.

The paper begins by recalling the essential principles of MBPC systems, by briefly outlining the origins of their use in the process industries, and by recording some of the theoretical issues associated with these systems, that are currently being examined. It proceeds with a particular focus on DMC. Its use in the control of process plants is discussed by reference to a simulated paper machine. Subject to the constraints imposed by commercial confidentiality, studies are then presented of application to a fluidised catalytic cracker in the petrochemical industry and to paper fibre recycle plants in the paper industry. The paper closes with a discussion of the benefit plant-wide optimisation systems can offer whole process plants, once MBPC systems have been implemented on the individual units making up the process.
Mathematical model for a micromachined accelerometer
Authors: Lewis C.P. , Kraft M. , Hesketh T.G.
Published: November 2007

A mathematical model is developed for both open- and closed-loop accelerometers having capacitive sensing and electrostatic feedback. Test results on actual micromachined devices are compared with simulation employing the mathematical model.
Missile autopilot controller design using state transformations and optimal LQR techniques
Authors: Jones Campbell
Published: November 2007

The design of a missile autopilot controller which provides a fast and stable response to guidance commands, and which maintains this performance throughout the entire flight envelope, provides a challenging problem to flight control engineers. This paper considers the design of a lateral acceleration autopilot controller for a generic cruciform missile, and shows how full state feedback can be applied following the transformation of a physical state space model of the missile to a form where all the states are measurable and the introduction of lateral acceleration and pitch rate error states. This facilitates the successful application of the oft-disparaged optimal Linear Quadratic Regulator (LQR) control technique. In addition to the error states, the particular optimal control formulation makes use of fin position feedback. Integral action on the acceleration error state is introduced to ensure zero steady-state error in the presence of uncertainties and unmodelled dynamics. Autopilot controller design is performed directly in the discrete domain. Lateral acceleration time histories and open-loop frequency response functions for two flight speeds of a range of incidences are used to illustrate performance. System robustness is assessed using the open-loop gain and phase margins. Prior to the autopilot control law design study, a detailed discussion of the role, function and performance requirements of a missile lateral autopilot is given.
PD-like fuzzy controllers compared with conventional PD controllers
Authors: Kortmann Peter
Published: November 2007

It is often claimed that fuzzy logic controllers are robust. This work contains a comparison of a PD-like fuzzy logic controller and a classical PD-controller applied to a vertical take off and landing (VTOL) laboratory scaled plane model in simulation studies and real-time control with regard to robustness against stochastic disturbances and parameter variations. An analytical description of the fuzzy controller is derived and compared with the PD-controller. The results show that a fuzzy controller is a priori not more robust against noisy disturbances than a conventional controller.
Pressure control of a Moscow water supply system using expert system technology
Authors: Coulbeck Bryan , Ulanicki Bogumil , Rance John P. , Deviatkov Vladimir V. , Kosov Sergei , Glukhovsky Iosiff
Published: November 2007

Automating the pressure control of typical Russian types of water distribution systems can result in greater than average benefits. The potential exists for improving the system efficiency and reliability while reducing the on-line operational manning requirements. To this end the paper presents modelling and simulation studies of the current semi-manual and the proposed fully automatic pressure control schemes for the Zelenograd water supply system. Dynamic operational simulations are an essential feature of the project. However, it was necessary to enhance the network hydraulic simulator, to include pressure feedback controls, in order to produce acceptable results. Analyses of the operational requirements and the simulation results provide a basis for the design of an improved controller using an expert system approach. A major part of the paper covers the methods in use for obtaining an adequate set of control rules for the Zelenograd system. Extended time period operational simulations are used to verify the rules and to compare the results with those of existing practice. There are expectations of immediate benefits in terms of operating economies. Typically these will arise from reductions in water leakage, electricity charges and control manpower. Work is now proceeding on actual implementation using a combination of expert system and fuzzy logic methods.
An intelligent sensor for distance estimation based on fuzzy data fusion
Authors: Baglio Salvatore , Graziani Salvatore , Pitrone Nicola
Published: November 2007

In this paper a new intelligent sensor for distance measurements is proposed. Both optical and acoustical sensors are adopted. Fuzzy data fusion methodologies have been applied in order to integrate the distance estimates of the different sensors. The introduced intelligent measurement system allows high quality distance estimation to be obtained in a wide operating range with low sensitivity to environmental noise. The experimental set-up and the metrological characterisation of the measuring system are reported.
Fuzzy logic in anaesthesia
Authors: Linkens D.A. , Mason D.G. , Abbod M.F. , Shieh J.S.
Published: November 2007

The development of on-line drug administration strategies in operating theatres represents a highly safety-critical situation. The usefulness of different levels of simulation prior to clinical trials has been shown in previous studies in anaesthesia. Thus, in earlier work on pole-placement self-tuning for muscle relaxation, a dual computer real-time simulation was undertaken, subsequent to algorithm validation via off-line simulation. In the present work, supervised fuzzy rule-based control algorithms are being used. The control software was implemented on the actual machine to be used in theatre, while another computer acted as a real-time patient simulator. It provides a fast design and simulation environment for safety-critical validation. The resultant validated controllers are now being used clinically.
Relationship between deadbeat and pole-placement discrete-time PID controllers
Authors: Warwick Kevin , Yong Ho Kang
Published: November 2007

This paper considers PID control in terms of its implementation by means of an ARMA plant model. Two controller actions are considered, namely pole placement and deadbeat, both being applied via a PID structure for the adaptive real-time control of an industrial level system.

As well as looking at two controller types separately, a comparison is made between the forms and it is shown how, under certain circumstances, the two forms can be seen to be identical. It is shown how the pole-placement PID form does not in fact realise an action which is equivalent to the deadbeat controller, when all closed-loop poles are chosen to be at the origin of the z-plane.
Adaptive control for a constrained robot without using a regressor
Authors: Leung T.P. , Su Chun-Yi
Published: November 2007

With the aim of controlling the motion/force of constrained robots with neither involving complex design procedurs or extensive on-line computations, this paper presents a new adaptive control strategy. The main advantage of the strategy, is its simplicity, in design for the programming code and real-time implementation. It is shown that the control objective is achieved without exact knowledge of robot dynamics or on-line calculation of non-linear dynamic functions. The control algorithm is constructed with at most four control parameters to be adjusted adaptively, and that number is determined independently of the number of links of the robot. To illustrate the developed method, a simulation example is presented.
Biped robot locomotion in the sagittal I plane
Authors: Medrano-Cerda G.A. , Eldukhri E.E.
Published: November 2007

This paper describes the control system for an eight-degree-of-freedom biped robot built at the University of Salford. The controller enables the robot to walk in the sagittal plane on smooth level terrain and is essentially an observer-based controller utilising state feedback, integral action and feedforward control. The robot posture is controlled by selecting constant reference set points for the control system. Locomotion is achieved by suitably modifying the reference set points. The robot walks with a step length of approximately 0.3 m and a speed of about 0.03 m/s.
State-space adaptive H∞ controller with application to a ship control system
Authors: Desanj D.S. , Grimble M.J. , Katebi M.R.
Published: November 2007

This paper is concerned with the design of a state-space H∞ self-tuning surface ship auto-pilot. A state-space approach is employed for the on-line recursive identification which lends itself readily to the H∞ problem formulation. To improve the robustness properties of the identification scheme, vector variable forgetting factor and UD factorisation of the covariance matrix are used. Two different methods for the controller design are described and conditions are given that allow suspension of parameter estimation and controller updating. Both approaches are used to design controllers that are robust to changes in ship speed and sea-states. The benefits of an advanced control design and the advantages of self-tuning capabilities are illustrated by means of non-linear simulations.
IDCOM - B multivariable model-predictive controller
Authors: Moro Tony L. , Bonavita Nunzio
Published: November 2007

In the last ten years Model Based Predictive Control (MBPC) has proved itself as one of the most successful advanced control tools. Its capability to handle processes with 'difficult' dynamics, has allowed improved control on critical loops with long time delays, constraints, feed-forwarding, over-rides, etc. Moreover, MBPC algorithms are able to perform multivariable control on processes characterised by strongly interactive loops, which have always been one of the toughest control problems. Due to the computational burden of such sophisticated algorithms, and the engineering skills required for a successful implementation, MBPC diffusion has been limited, in most cases, to 'money-making-loops', above all in the chemical and petrochemical fields, where even small increases in efficiency or yield produce major savings. The great progress in utilising the always increasing power of digital computers, and in developing and improving user-friendly software environments, provides opportunities for applying highly sophisticated control techniques more quickly, easily and cheaply.

This paper introduces the new IDCOM-B™ controller; that is, the first multivariable model-predictive control package completely embedded in a DCS as a modular control function. Its unique capability to run inside a standard INFI90 control module, sharing with the base regulatory loops the communication channels, control database and operator interfaces, avoids the cost of an external computer and all the efforts required to interface it with a DCS architecture.
Moving Horizon State Estimation for a bioprocesses modelled by a neural network
Authors: Flaus J.M. , Boillereaux L.
Published: November 2007

In this article, we propose a Moving-Horizon State-Estimation method, applied to a neural dynamical process model. Firstly, the approach chosen to represent a nonlinear dynamical system by a neural network is explained. After that, the MHSE method, used to perform the state estimation, is presented. The algorithm performances are showed on a biotechnological process. The combination of the MHSE method and the neural network permits a particularly efficient estimation of the state of the process. with a nonlinear model easy to build thanks to the neural network, and with an easy tuning due to the choice of the MHSE method.
Adaptive neural network control of flexible joint manipulators in constrained motion
Authors: Ge S.S. , Woon L.C.
Published: November 2007

This paper addresses the control problem of flexible joint manipulators in constrained motion. The singular perturb ation method is applied to reduce the original system into slow and fast subsystems. By adopting the composite control strategy, an adaptive neural network controller is first developed to control the slow subsystem. Then a fast feedback control is designed to stabilise the fast subsystem along its equilibrium trajectory. The system stability is proven using Lyapunov theory. It is shown that the motion tracking error converges to zero asymptotically, whereas the force tracking error remains bounded and can be made arbitrarily small. Numerical simulations are provided to show the effectiveness of the approach.
Nonlinear Dynamic Matrix Control using Local Models
Authors: Townsend S. , Lightbody G. , Brown M.D. , Irwin G.W.
Published: November 2007

This paper proposes using a Local Model (LM) network representation of a nonlinear chemical process as a basis for nonlinear Dynamic Matrix Control (DMC). The LM network is composed of local linear ARX models and is trained using a hybrid learning approach. The nonlinear DMC uses step responses for different process operating points extracted from the LM network, rather than the single-step response model of linear DMC. Simulation studies of a pH neutralisation process indicate improve ments in both set point tracking and disturbance rejection.
Microelectrode devices for manipulating and analysing bioparticles
Authors: Burt Julian P. H. , Pethig Ronald , Talary Mark S.
Published: November 2007

Micro-fabrication techniques, such as photo- and electron beam lithography and etching processes, are currently being used to develop microelectrode structures and new devices for applications in biomedicine and biotechnology. With these devices various types of bioparticle can be subjected to strong inhomogeneous electric fields, rotating fields or travelling fields. These fields can be generated over a wide range of electrical frequencies, so that the characteristic dielectric properties of the bioparticles can be tharaughly diagnosed or exploited. This article describes how the AC electrokinetic techniques of dielectrophoresis (motion of particles in inhomogeneous fields) and electrorotation can be used to detect or selectively manipulate cells and micro-organisms. New results, employing travelling field dielectrophoresis, of the separation of red and white blood cells and of the selective separation and concentration of viable yeast cells, are also presented.
Gamma - ray tomography in fluidised beds using a gamma camera
Authors: Bom V.R. , van Eijk C.W.E. , Jonkers G. , Por P.T. , van de Vorst J.G.G.
Published: November 2007

This paper describes the design and the optimisation of a gamma-ray tomography tool to be used for the measure ment of the particle density in fluidised beds. The set-up consists of a radioactive line source (35 cm long) perpendicular to the axis of the bed (15 cm diameter) and a standard medical gamma camera equipped with a lead collimator (~ 0.02 rad acceptance angle). An optimum gamma-ray energy of ~ 200 keV is deduced. It is shown that no corrections for imperfect collimation are necessary given the small acceptance angle of the collimator. It is estimated that the density profile can be obtained with an absolute accuracy of ± 25 kg/m3 and a spatial resolution of 2.5 mm. The maximum source strength is limited by the maximum count rate of the gamma camera. With a 75Se source of 130 mCi the measuring time for a density profile under the assumption of cylinder symmetry is in the order of 150 s.
On the estimation of on-off valve parameters for control of programmable pneumatic actuators
Authors: Hongbing Wang  , Mo John P.T. , Chen Nelson
Published: November 2007

In order to obtain accurate positional and velocity control of a pneumatic actuator system, it is essential to understand how the components in the system work and how they are intergrated. In general, the behaviour of most of the systems can be described mathematically. For examples, the pneumatics of the actuator is easy to model with reasonable accuracy because the geometrical characteristics of the cylinder are usually well understood. However, the control components such as valves are generally more complex because no universal mathematical method exists to describe them adequately. In order to reduce the system cost, simple low-cost on-off valves are used. The nonlinearity associated with on-off valve operation gives rise to more uncertainty in the model. This paper addresses this problem by proposing a novel approach to determine the mathematical model of the pneumatic on-off valve accurately from some simple experimental data. Once the model parameters are calculated by this method, the model can be used as part of a model reference adaptive control algorithm which incorporates the on-off valve model to improve the universal controllability of the pneumatic actuator.
The laser in manufacture - its use in the soldering of electronic assemblies
Authors: Beckett P.M. , Fleming A.R. , Gilbert J.M. , Whitehead D.G.
Published: November 2007

As a means of applying heat energy for soldering, lasers can offer a realistic solution to certain problem areas in electronics assembly. There are, however, limitations as well as advantages to the technique and an understanding of both is essential for its successful application. The Laser Soldering Group at Hull has been investigating the use of lasers for soldering purposes and in this paper we are concerned with the application of semiconductor diode lasers to the soldering of electronic assemblies. Using specific industrial applications as examples this paper highlights the difficulties as well as the benefits in the use of lasers for soldering.
Management of a robotised system on an Ethernet network
Authors: Vendrell E. , Mellado M. , Ballester E. , Navarro S.F. , Diaz J.R.
Published: November 2007

One of the most important problems for industrial implantation of Flexible Manufacturing Systems is communication between different devices and computers. The standardised use of local area networks (LANs), together with the power of available computers has significantly reduced communications difficulties. The next key challenge to be addressed is that of enhanced robot programming to implement integrated manufacturing processes. A proposal to operate a robotised system through an Ethernet network is presented in this paper. The system uses LAN features and socket programming to (i) implement a computer-robot link to allow an off-line robot programming, (ii) share the robotised system from a computer server and (iii) monitor all tasks, and corresponding status of the system from any node in the LAN.
Fault diagnosis and fault-tolerant estimation of a rail traction system via fuzzy observers
Authors: Chen J. , Patton R.J. , Lopez-Toribio C.J.
Published: November 2007

This paper studies the fault diagnosis and fault-tolerant estimation problems of a rail traction system. The main idea is to use a bank of fuzzy observers to detect faults and to isolate failed sensors. Once the failed sensor is isolated, the fuzzy observer driven by healthy sensors provides reliable torque and flux estimates which are used for the control purpose. The concept and design procedures for fuzzy observers are presented in this paper. A fuzzy observer is able to produce accurate state estimations and generate robust residuals for non-linear dynamic systems such as a rail traction system. The fault diagnosis and fault-tolerant estimation scheme proposed for the rail traction system is demonstrated using simulations.
On the design of command and stability augmentation systems for advanced technology aeroplanes
Authors: Cook M.V.
Published: November 2007

There exists an enormous wealth of published material describing the application of so called, 'modern control methods' to the design of fliglat control systems for piloted aeroplanes. It is also evident, with the exception of a very small number of recent applications, that there is a conspicuous lack of enthusiasm on the part of the airframe manufacturers to adopt this design technology, especially for the design of command and stability augmentation systems for piloted aeroplanes. It is possible to speculate on the reasons for this apparent lack of interest, but to do so might well result in a misplaced condemnation of modern control methods. Since evidence exists to suggest that some modern control system design strategies have overlooked important flight dynamics considerations, the discussion is turned around here by drawing attention to some of the more important considerations in command and stability augmentation system design. The object is, therefore, to inform the designer, of whatever persuasion, of the critically important aspects of command and stability augmentation system design for the advanced technology aeroplane.
Multimedia and process control interfaces: signals or noise?
Authors: Alty James L.
Published: November 2007

Multimedia interfaces are examined and the nature of current input and output media identified. A number of design objectives for multimedia inteifaces are suggested - improving efficiency, learning and providing a stimulating problem-solving environment. The key problem of how to choose an appropriate medium for a particular interface situation is analysed and the concept of a signal-to-noise ratio for measuring media expressiveness is tentatively postulated. Some recent work in process control is then examined and the results interpreted from the signal-to-noise ratio viewpoint. These are then related to the concept of media expressiveness.
Human supervisory control of aircraft, rail and highway vehicles
Authors: Sheridan Thomas B.
Published: November 2007

This paper reviews recent trends in control of aircraft, rail and highway vehicles toward supervisory control. Supervisory control means the human operator intermittently specifies goals, constraints and procedural information to a computer, monitors synoptic displays of state information, and tasks the computer to execute the instructions automatically. This trend has been driven by new sensor, communication and computer technology. Full automation of these transport systems is currently unacceptable, not only for reasons of safety, but also because radical departure from present systems is technologically and economically infeasible, in addition to which the public does not like radical change. Commercial and military aircraft are easily the most advanced of the three transportation modes. Rail and highway systems are currently undergoing rapid transformation, nevertheless impeded by economic and other societal constraints. Examples of new technological developments are given for each mode. Common problems are then described. Finally, some methodological elements are mentioned which are essential to resolving these problems.
Latin America and China Under Global Neoliberalism
Authors: Jilberto Alex E. Fernández , Hogenboom Barbara
Published: November 2007

While China and Latin America simultaneously implemented neoliberal policies as part of a profound economic restructuring process, there are important differences in the results of their policies and economic performance. This article discusses the different development paths of Latin America and China, including their starting points, economic policies and political processes. China's expansion and Latin America's liberalization have brought the two in much closer contact. Several Latin American countries are now important providers of commodities (for example, minerals, energy and soy) that China needs to keep up with the rising levels of production and consumption. As a result China is also starting to invest in these products. Some other Latin American countries have lost rather than gained from the rise of China, especially the countries that sought economic integration in the world market through the growth of maquiladoras (assembly factories for export to the United States). However, their attempts to slow down China's entry into the World Trade Organization (WTO) did not succeed.The article discusses the causes, effects and prospects of these different experiences with China's global expansion.
The Living Arrangements of Children and Their Educational Well-Being
Authors: Teachman Jay D.
Published: November 2007

The author uses data from the 1997 and 1999 rounds of the National Survey of America's Families to estimate a set of descriptive regression equations examining the relationship between a detailed measure of childhood living arrangements and the educational well-being of children measured as their engagement in school and participation in extracurricular activities. He considers three dimensions of family environment linked to childhood living arrangements that might generate differences in school engagement and participation in extracurricular activities. These dimensions of family environment are turbulence (degree of instability in children's social and physical environment), parenting context (parental activities experienced by children), and economic resources (family income relative to poverty). The author finds strong bivariate relationships between childhood living arrangements and the measures of educational well-being that are reduced and sometimes eliminated when differences in turbulence, parenting, and economic resources are controlled.
More evidence on competing cognitive systems
Authors: Felix Sascha W.
Published: November 2007

This paper deals with the question of why adults, as a rule, fail to achieve native-speaker competence in a second language, whereas children appear to be generally able to acquire full command of either a first or second language. The Competition Model proposed in this paper accounts for this difference in terms of different cognitive systems or modules operating in child and adult language acquisition. It is argued that the child's learning process is guided by a language-specific module, roughly equivalent to Universal Grammar (cf. Chomsky, 1980), while adults tend to approach the learning task by utilizing a general problem-solving module which enters into competition with the language-specific system. The crucial evidence in support of the Competition Model comes from a) the availability of formal operations in different modules and b) from differences in the types of utterances produced by children and adults.
The abstractness hypothesis and morphemic spelling
Authors: Luelsdorff Philip A.
Published: November 2007

The acquisition of orthography in spelling and reading has seldom been the object of linguistic inquiry due to the common misperception that orthography has no place in grammar. Orthography should be accorded the status of a com ponent of grammar, however, since its units are linguistic signs and the con straints on errors in spelling and reading are similar to those in phonology, syntax, and semantics (Luelsdorff, 1986).

Systemic deviation from phoneme-grapheme biuniqueness is the major source of error in the acquisition of a native or foreign alphabetic script. Such deviation is graphemically ambiguous if the relation between grapheme and phoneme is many-to-one and phonetically ambiguous if the relation between grapheme and phoneme is one-to-many. A special case of phonetic ambiguity is morphemic spelling.

In this paper we study the acquisition of the uniform  morphemic spell ing of the regular allomorphs of the English past tense morpheme, / Id/, /d/, and /t/, in a large sample of German school children in all the grades of the secondary system of education, the Hauptschule, the Realschule, and the Gymnasium. First, whereas we do find consistent improvement from school system to school system, we reject the view that pupils' performance necessarily improves from grade to grade. Secondly, we find fairly consistently better per formance on / Id/ than /d/ and on /d/ than /t/. This distribution we explain by the Abstractness Hypothesis according to which orthographic representa tions which are less abstract are acquired earlier than those which are more abstract, where abstractness is measured in terms of the number of rules relat ing the orthographic representations to the phonetic ones. Thirdly, the Abstractness Hypothesis also predicts the relative frequencies with which these allomorphs are misspelled and the actual major misspelling types of the regular allomorphs of the past tense morpheme themselves.

The Abstractness Hypothesis on the acquisition of morphemic spelling invites testing in other areas of morphemic and partially morphemic spelling, such as derivationally related pairs, the possessive, the regular past participle, the third person singular, and the plural.
A case for 'acquisitional strategies': some methodological observations on investigation into second language learners' initial state'
Authors: Polomska Margaret
Published: November 2007

This article reports on a pilot investigation into initial assumptions of second language learners in the methodological framework of 'acquisitional strategies'.2 Its focus is predominantly methodological, but experimental data is used to illustrate the approach. Acquisitional strategies constitute an elaboration of recent applications of the parameter setting model of grammar to the investigation of second language learners' initial state in that in this framework markedness and parameter setting interact with cognitive and psycholinguistc factors. Acquisitional strategies are understood as an identifiable, but subconscious plane according to which acquisition is handled and which is based on a subconscious assumption or a range of assumptions about the linguistic characteristics of the language under acquisition. Learners' initial state or their assumptions are seen as reflected empirically by a range of interacting formal and substantive choices, attached to a particular grammatical phenomenon. In contrast to the parameter setting model, the analysis of second language learners' initial state in the context of acquisitional strategies is essentially individual-based. An exploratory application of this framework to the investigation of second language learners' initial state has been undertaken in the context of acquisition of preposition stranding by English learners of Dutch. Preposition stranding refers to a marked phenomenon where movement extracts an NP complement of the preposition out of PP, leaving the preposition 'stranded' behind. The respective realization of this phenomenon in English and Dutch manifests interesting syntactic and morphological contrasts, which render it a valuable empirical tool for evaluation of acquisitional strategies. A tendency to statistically significant individual choices has been noted in this study. The predominant choice, manifested by the subjects, appears to be a strategy associated here with the assumption of nonequivalence of the phenomenon of preposition stranding in English and in Dutch.
Cognitive process in second language reading: transfer of L1 reading skills and strategies
Authors: Koda Keiko
Published: November 2007

Two crosslinguistic experiments were conducted with 83 skilled readers from four contrasting L1 orthographic backgrounds. Experiment 1 tested the effects of blocking either visual or sound information on lexical decision-making. Experiment 2 examined the effects of heterographic homophones (e.g. eight and ate) on reading comprehension. Data from the two experiments demonstrate that the subjects utilize cognitive skills and strategies developed in their L 1 when reading English as an L2, suggesting that (a) L1-L2 cognitive process transfer does take place in L2 reading and also that (b) orthographic structure exerts a significant influence on cognitive processess in reading.
Anecdotes of accidents: second language research going awry and telling us why
Authors: Cumming Alister , Swain Merrill
Published: November 2007

Internationally recognized experts in second language research were asked to provide anecdotes documenting memorable incidents where something had gone awry in their research. The anecdotes proved to emphasize problems of a technical, conceptual, or political nature. Fifteen anecdotes representing these three kinds of problems are presented. In common, the anecdotes express concerns for scientific realism, that is, second language research was said to go wrong in cases where legitimate claims for knowledge were undermined - by accidents, unforeseen intrusions, or misconceptions. This view of constraints on second language research, based on researchers' experiences (rather than theoretical polemics or methodological prescriptions), may be valuable for learning researchers, users of research results, and critical analyses of second language research processes.
Do second language learners acquire restrictive relative clauses on the basis of relational or configurational information? The acquisition of French subject, direct object and genitive restrictive relative clauses by second language learners
Authors: Hawkins Roger
Published: November 2007

Much of the work on the second language acquisition of restrictive relative clauses has made reference to the similarities between learners' order of diffi culty and Keenan and Comrie's (1977) typologically determined noun phrase accessibility hierarchy for relativisation (AH). There has been little considera tion, however, of whether this 'theory of markedness' (for that is the implica tion of citing the AH in the context of second language learning) actually determines the way that second language learners develop rules for restrictive relative clauses. The present study examines the way that learners of L2 French construct rules for French relativiser morphology from this perspective. It is found that there is no evidence to support the view that learners make use of a theory of markedness like the AH in constructing such rules. Rather, learners appear to construct rules on the basis of the linear ordering of the constituents of restrictive relative clauses in surface configurations. From the evidence it is suggested that 'markedness' in the development of L2 restrictive relative clauses is not a feature of the grammatical component of learners' linguistic knowledge, but is a feature of their L2 processing capacity.
Parameter setting and the acquisition of word order in L2 French
Authors: Hulk Aafke
Published: November 2007

In this article we discuss the theoretical implications of an experimental pilot study on the acquisition of word order properties in L2 French by Dutch native speakers. We expected the IL of our L2 learners to show the interaction of three parameters: the Head parameter, a (target of) verb movement parameter and a topicalization to SPEC, CP parameter. Our results appear to support these hypotheses. The Dutch L1 speakers clearly started out with a SOVI word order in their first stage of French L2 acquisition. They quite easily reset the Head Parameter for which there is positive evidence in French. Resetting of the Topicalization Parameter, however, for which we argued negative evidence to be necessary, was much more difficult. Interestingly, the L2 learners appear to adopt grammars that have parameter settings that correspond neither to Dutch, their L1, nor to French, their L2. Those parameter settings however are possible according to the constraints of UG and indeed are found in other languages. Concerning the actual order of sequences in this L2 French acquisition, we found a striking similarity to the scenario found in French language change. Summarizing, we have provided support for the UG approach of L2 acquisition. However, in doing so, we have also raised some new questions, particularly with respect to the difference between German and French L2 acquisition in resetting certain parameters.
On triggering data in L2 acquisition: a reply to Schwartz and Gubala-Ryzak
Authors: White Lydia
Published: November 2007

In this reply, I address certain issues raised by Schwartz and Gubala-Ryzak (1992), who argue that White (1991a) is mistaken in claiming that negative evidence can lead to parameter resetting in L2 acquisition. I suggest that, although Schwartz and Gubala-Ryzak's reanalysis of White's findings solves a number of empirical and conceptual problems, their analysis raises new problems in its turn. Empirical evidence from French learners of English is presented which suggests that positive L2 data do not guarantee the loss of L1 parameter settings. The implications of this finding are discussed.
Pragmatic transfer
Authors: Kasper Gabriele
Published: November 2007

Throughout the short life of interlanguage pragmatics as a subdiscipline of second language research, it has been a virtually uncontested assumption that non-native speakers' comprehension and production of linguistic action is considerably influenced by their L1 pragmatic knowledge. The literature strongly supports this hypothesis. However, whereas there has been a lively controversy about the role of transfer in the traditional core areas of second language research (syntax, morphology, semantics), there has been little theoretical and methodological debate about transfer in interlanguage pragmatics.

As a contribution to such a debate, this article seeks to clarify the concept of pragmatic transfer, proposing as a basic distinction Leech/Thomas' dichotomy of sociopragmatics versus pragmalinguistics and presenting evidence for transfer at both levels. Evidence for purported pragmatic universals in speech act realization and for positive and negative pragmatic transfer is discussed. Further issues to be addressed include the conditions for pragmatic transfer (transferability), the interaction of transfer with non-structural factors (proficiency, length of residence, context of acquisition), and the effect of transfer on communicative outcomes. The article concludes by briefly considering some problems of research method in studies of pragmatic transfer.
A second language classic reconsidered - the case of Schachter's avoidance
Authors: Kamimoto Tadamitsu , Shimura Aki , Kellerman Eric
Published: November 2007

This article reconsiders one of the classic articles in the second language literature, Schachter's 'An error in error analysis', in the light of subsequent work on avoidance. Such work is essentially of two kinds, either building on and refining the concept of avoidance, or offering alternative explanations for Schachter's findings. While avoidance as a genuine phenomenon is not proved or disproved by Schachter's data, hypotheses based on her figures suffer from the lack of methodological detail in her original study. In order to be able to establish whether avoidance is a feasible explanation for relative underproduction by a group of learners, it is necessary to look at the first language form, distribution and function of the entity supposedly being avoided in the L2 as well as the means being used to establish whether and to what extent the entity is already part of the L2 knowledge of members of that group.
Incomplete vs. divergent representations of unaccusativity in non native grammars of Italian
Authors: Sorace Antonella
Published: November 2007

The term 'near-native', used to refer to speakers at the most advanced stage of second language acquisition, may denote either incompleteness of their competence (lack of given L2 properties) or divergence (interlanguage representations of L2 properties that are consistently different from native representations). An undifferentiated use of the term conceals the fact that incompleteness and divergence are two distinct states of grammatical compe tence, corresponding to two qualitatively different kinds of ultimate attain ment. This article looks at the linguistic intuitions of French L1 and English L1 near-native speakers of Italian L2 about some syntactic and semantic properties related to unaccusativity in Italian, and concludes that the near-native grammar of French subjects exhibits divergence whereas the near-native grammar of English subjects exhibits incompleteness. It is argued that these competence differences reflect differences in the overall repre sentations of unaccusativity in French and English.
Resetting Universal Grammar parameters: evidence from Second Language Acquisition of Subjacency and the Empty Category Principle
Authors: Uziel Sigal
Published: November 2007

This article is concerned with whether the principles of UG are available in adult Second Language Acquisition (SLA) as in child first language acquisi tion. My hypothesis is that these principles are fully available to the L2 learner, and that the process of L2 acquisition is, in fact, a process of parameter-reassignment or new assignment in which the L2 learner resets the parameter-values of the L1 to their values in the L2. In order to test this hypothesis, I built on previous work by Martohardjono (1991) and conducted a study which examined the acquisition of two principles of UG, Subjacency and the Empty Category Principle, by native speakers of Hebrew learning English as a second language. I made a series of predictions with respect to the patterns of acquisition for various constructions in the target language, based on the assumption that L2 grammars are systems of knowledge guided by the internal logic, or 'systematicity' specified by UG. These predictions were borne out by the results of my study, leading to the conclusion that UG is indeed available in SLA. My conclusion corroborates other studies in the field which have reached similar conclusions (e.g., Flynn, 1987; White, 1988 and Martohardjono, 1991).
Second language acquisition: past, present and future
Authors: Gass Susan M.
Published: November 2007

This article considers the relationship between second language acquisition (SLA) and other disciplines. It begins by reviewing the history of SLA studies, relating them to the broader picture of applied linguistics and language pedagogy. It is argued that the recognition of SLA as a field which can make valuable contributions to other fields is essential for the continuation and vitality of the field. Specific examples of how SLA has been important to the fields of linguistics, pedagogy and psychology are given.
Understanding text in a second language: a psychological approach to an SLA problem
Authors: Jenkin Heather , Prior Suzanne , Rinaldo Richard , Wainwright-Sharp Ann , Bialystok Ellen
Published: November 2007

The study is an attempt to assess the way in which second language learners form mental representations of information they read. Subjects were asked to read passages in their first and second languages and to demonstrate comprehension of the information by using it to make a judgement of a visual display of the same information. Following this there was a surprise recognition task to determine whether or not they still had access to verbatim representations of the passages. The results showed that information read in a second language is represented differently from the same information read in subjects' first language.
Second language acquisition: perceptions and possibilities
Authors: Schachter Jacquelyn
Published: November 2007

In this article I shall attempt to characterize some of the stresses and strains experienced by researchers in the field of second language acquisition (SLA), both intellectual and personal. I shall offer my perspective on how we are responding, and how we should be responding, to those stresses and strains. Together with this discussion of academic politics, I will interweave two research lines I consider important, research lines unique to the field of SLA, which should have impact both on linguistic theory making and on appropriate pedagogical decisions involving language classrooms.