bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of insomnia in high level residential aged care facility residents
Authors: Scherer Samuel C , Rule Jeanette , Fischer Melanie , Jacobs Elizabeth , Dobson Lois , De La Rue Heather , Browning Michael , Duffus Josephine , Gibson Stephen J , Darzins Peteris
Published: November 2007

Insomnia is common in nursing home settings but assessment and management of sleep disturbance is often suboptimal. New assessment procedures that target potentially remediable clinical causes of insomnia were implemented and evaluated at two high level residential aged care Facilities (HLRACFs) (formerly called nursing homes), in Melbourne, Australia. Fifty‐eight of 147 residents (39%) who complained of insomnia, or were nominated by nursing staff as having disturbed sleep, and had confirmation of sleep disturbance on overnight sleep log, were provided with a structured assessment protocol. A multidisciplinary team then considered the causes of each resident's insomnia. A potentially remediable medical or psychiatric cause was identified in 66% of residents with insomnia. More than one such factor was identified in 34%. Pain was a likely factor in 39%. Depression was a likely factor in 30%. Insomnia, depression and pain were significantly correlated.
Building capacity in ageing research: Implications from a survey of emerging researchers in Australia
Authors: Bartlett Helen , Underwood Mair , Peach Linda
Published: November 2007

Objective:  The National Emerging Researchers in Ageing Study (NERAS) set out to inform capacity‐building efforts in ageing research. Its purpose was to identify the interest, attitudes and motives of PhD students to enter the field and factors influencing intention to remain.

Method:  A web‐based survey was sent to 267 PhD students in ageing. It assessed attitudes towards older people and the importance of a variety of factors influencing students’ interest and decision to engage in ageing research.

Results:  The response rate was 60% (n = 161). Positive attitudes, interest in ageing issues and concern for older people were key motivating factors to work or study in the field. Supervisors in ageing and initial interest in the field were key predictors of intention to remain in the field.

Conclusions:  NERAS is the first national study of emerging researchers in ageing and it provides important new knowledge with implications for capacity‐building efforts.
Effects of Cadmium on Polar Lipid Composition and Unsaturation in Maize (Zea mays) in Hydroponic Culture
Authors: Chaffai Radhouane , Seybou Tinni Nouhou , Marzouk Brahim , El Ferjani Ezzedine
Published: November 2007

This study aimed to evaluate the effect of Cd exposure (100 μmol/L) on polar lipid composition, and to examine the level of fatty acid unsaturation in maize (Zea mays L.). In roots, the level of 16:0 and monounsaturated fatty acids (16:1 + 18:1) decreased in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In contrast, the proportion of unsaturated 18‐C fatty acid species showed an opposite response to Cd. The content, on the other hand, of PC, PE, digalactosyldiacylglycerol (DGDG), and steryl lipids increased in roots (2.9‐, 1.6‐, 5.3‐, and 1.7‐fold increase, respectively). These results suggest that a more unsaturated fatty acid composition than found in control plants with a concomitant increase in polar lipids may favor seedling growth during Cd exposure. However, the observed increase in the steryl lipid (SL) : phospholipid (PL) ratio (twofold), the decrease in monogalactosyldiacylglycerol (MGDG) : DGDG ratio, as well as the induction of lipid peroxidation in roots may represent symptoms of membrane injury. In shoots, the unsaturation level was markedly decreased in PC and phosphatidylglycerol (PG) after Cd exposure, but showed a significant increase in sulfoquinovosyldiacylglycerol (SQDG), MGDG and DGDG. The content of PG and MGDG was decreased by about 65%, while PC accumulated to higher levels (4.4‐fold increase). Taken together, these changes in the polar lipid unsaturation and composition are likely to be due to alterations in the glycerolipid pathway. These results also support the idea that the increase in overall unsaturation plays some role in enabling the plant to withstand the metal exposure.
Novel Combination of Atomic Force Microscopy and Epifluorescence Microscopy for Visualization of Leaching Bacteria on Pyrite
Authors: Mangold Stefanie , Harneit Kerstin , Rohwerder Thore , Claus Günter , Sand Wolfgang
Published: November 2007

Bioleaching of metal sulfides is an interfacial process comprising the interactions of attached bacterial cells and bacterial extracellular polymeric substances with the surface of a mineral sulfide. Such processes and the associated biofilms can be investigated at high spatial resolution using atomic force microscopy (AFM). Therefore, we visualized biofilms of the meso-acidophilic leaching bacterium
Acidithiobacillus ferrooxidans
strain A2 on the metal sulfide pyrite with a newly developed combination of AFM with epifluorescence microscopy (EFM). This novel system allowed the imaging of the same sample location with both instruments. The pyrite sample, as fixed on a shuttle stage, was transferred between AFM and EFM devices. By staining the bacterial DNA with a specific fluorescence dye, bacterial cells were labeled and could easily be distinguished from other topographic features occurring in the AFM image. AFM scanning in liquid caused deformation and detachment of cells, but scanning in air had no effect on cell integrity. In summary, we successfully demonstrate that the new microscopic system was applicable for visualizing bioleaching samples. Moreover, the combination of AFM and EFM in general seems to be a powerful tool for investigations of biofilms on opaque materials and will help to advance our knowledge of biological interfacial processes. In principle, the shuttle stage can be transferred to additional instruments, and combinations of AFM and EFM with other surface-analyzing devices can be proposed.
NATURE OF THE PHASE TRANSITION IN QCD AT FINITE TEMPERATURE
Authors: MENDES TEREZA
Published: November 2007

It is clear that the order of the deconfining phase transition in QCD at nonzero temperature and density (with realistic quark masses) is of great experimental interest. The importance of the transition at zero baryon density with only two (degenerate) quark flavors is perhaps less evident. As a matter of fact, the order of the transition in this case is still an open problem and corresponds to the last question mark in the zero-density phase diagram of QCD. We argue that establishing the nature of the transition in this case is also a crucial test for numerical simulations of lattice QCD, allowing precise estimates of the possible systematic errors related to the choice of fermion-simulation algorithm and of discretized formulation for fermions.
PHASE DIAGRAM OF THE THREE DIMENSIONAL FOUR FERMI MODEL WITH FINITE N CORRECTIONS
Authors: KNEUR JEAN-LOÏC , PINTO MARCUS BENGHI , RAMOS RUDNEI O. , STAUDT EDERSON
Published: November 2007

We study the phase diagram of the 3d massless Gross–Neveu model with different numbers of fermionic species, N. Using the Optimized Perturbation Theory technique, the free energy is evaluated at finite temperature and chemical potential. The analytical results allow us to calculate critical quantities for any value of N and, in the present work, we choose de values N = 1,3,4,10. In addition, we determine the evolution of the tricritical points, in the temperature versus chemical potential plane for these different values of N.
ANALYZING HADRON-QUARK MATTER PHASE TRANSITION BY MACROSCOPIC PROPERTIES OF NEUTRON STARS
Authors: GROHMANN M. , JACOBSEN R. B. , RAZEIRA M. , VASCONCELLOS C. A. Z. , BODMANN B. E. J. , MARRANGHELLO G. F. , DILLIG MANFRED
Published: November 2007

A complementary way to investigate the Hadron-Quark-Gluon Phase transition in heavy ion collisions is to analyze properties of dense astrophysical objects, i.e. neutron stars. A neutron star can be simply described as a giant nucleus. However, due to the enormous gravitational contraction, it can reach densities up to several times the density found in the Pb nucleus. This property allows the formation of a core made up of free quarks and gluons. Once this new phase is formed, the new state drastically changes the neutron star macroscopic properties, such as its mass and radius. In the present work, we follow a route opposite to the common sense, investigating the properties of the phase transition by analyzing neutron star properties of mass and radius. This observations can determine the density where the transition can occur or the order of the transition using some sort of reverse engineering. As a consequence, the values of the bag constant or the strong coupling constant can be inferred.
SIMULATING DCC SIGNALS IN COSMIC RAYS
Authors: VIANA PEDRO , FRAGA EDUARDO S. , DE MELO NETO JOÃO R. T.
Published: November 2007

We investigate the production of disoriented chiral condensates in ultra high energy collisions and look for an intrinsic signature they could produce in ongoing and future cosmic ray experiments. This is implemented by studying the atmospheric showers generated after the chiral symmetry breakdown. We also speculate on the nature of the events and its connection with Centauro and anti-Centauro observations. Some preliminary results are presented.
THE ω → π+π−π0 PROCESS IN 3H AND 3He PHOTODISINTEGRATION
Authors: MAGALHÃES P. C. , BOITO D. R. , ROBILOTTA M. R. , ZARNAUSKAS G. R. S.
Published: November 2007

We study the decay ω(782) → π+π−π0, which can contribute as an intermediate process to the photodisintegration of 3 H and of 4 He . In the calculation of this amplitude, performed by means of chiral effective Lagrangians, we study the role of the contact term and the ρ(770) resonance contributions. Dalitz plots are built with different values for the ρ mass and width. Our best result is obtained without the contact term.
BACKWARD RAPIDITY DISTRIBUTIONS IN COLOR DIPOLE MODEL
Authors: DE OLIVEIRA EMMANUEL GRÄVE , GAY DUCATI MARIA BEATRIZ , BETEMPS MARCOS ANDRÉ
Published: November 2007

The color dipole model is traditionally applied to forward rapidities. Alternatively, we employ the dipole model to obtain backward rapidity distributions. We have chosen to work with dilepton production in pAu and pp collisions at RHIC and LHC energies. The results are best understood with the help of a nuclear modification factor RpA as a function of transverse momentum and of rapidity. As it is found, dilepton production at backward rapidities is very dependent on nuclear effects.
RELATIVISTIC EFFECTS OF MIXED VECTOR-SCALAR-PSEUDOSCALAR POTENTIALS FOR FERMIONS IN 1+1 DIMENSIONS
Authors: CASTRO L. B. , DE CASTRO A. S. , HOTT M.
Published: November 2007

The problem of fermions in the presence of a pseudoscalar plus a mixing of vector and scalar potentials which have equal or opposite signs is investigated. We explore all the possible signs of the potentials and discuss their bound-state solutions for fermions and antifermions. The cases of mixed vector and scalar Pöschl–Teller-like and pseudoscalar kink-like potentials, already analyzed in previous works, are obtained as particular cases.
ROLE OF SHORT RANGE INTERACTIONS IN THE CHARGE OF MAXIMUM ADSORPTION
Authors: BASHA C. AHMED
Published: November 2007

Adsorption of solvent or organic compounds at a metal/interface is characterized by a wide spectrum of interactions governing the phenomenon under effective fields of order ≈ 107 V/cm . A generalized spin-1 Ising Hamiltonian was formulated by considering various interactions under molecular field approximation (MFA) to arrive at a three-state model of adsorption isotherm (i.e. the joint adsorption of two different organic compounds in the presence of solvent molecules). A general multi-state model was deduced heuristically and an expression for the charge [Formula: see text] at which maximum adsorption (θmax) occurs derived explicitly for a three-state site parity model that incorporates short-range interaction energies, functional dependence of permanent and induced dipole moments of the organic adsorbate, and the solvent and substrate interactions.
THEORETICAL, EMPIRICAL AND EXPERIMENTAL ELECTRON AFFINITIES OF SF6: SOLVING THE DENSITY FUNCTIONAL ENIGMA
Authors: JALBOUT A. F. , DE LEON A. , ADAMOWICZ L. , TRZASKOWSKI B. , CHEN E. C. M. , HERDER CHARLES , CHEN E. S.
Published: November 2007

We postulate that the adiabatic electron affinity of SF6 is 2.40(10) eV, obtained from the photodetachment onset, 3.2(1) eV and a rearrangement energy of 0.8(1) eV. This eliminates the perceived "SF6 density functional enigma". All of the experimental electron affinities are evaluated and 14 significantly different values selected to construct empirical anionic Morse potentials. These values are (in eV): 2.40(10) 2.20(10), 2.00(10), 1.80(10), 1.60(10), 1.20(10), 1.07(7), 0.93(10), 0.80(10), 0.63(10), 0.43(10), 0.30(10), 0.10(10), and 0.0(2). Comparisons are made to theoretical calculations and relative bond orders. The calculated electron affinities of SF6 are: density functional, 1.6–3.0 eV; ab initio, -1.0–2.2 eV; semiempirical, 0.1–2.2 eV, and for SF5 is 0.3–3.8 eV. Curves calculated using semiempirical, density functional and ab initio procedures are similar to the anionic Morse potentials. This work attempts to correct for differences in the EA calculated for this species.
A THEORETICAL STUDY ON THE MECHANISM OF 2:1 1, 3 DIPOLAR CYCLOADDITION REACTIONS
Authors: WANG JING-FANG , WEI DONG-QING , WANG CHUN-FANG , YE YONG , LI YI-XUE , LUO YONG , WANG WEN-WU , LIU LUN-ZU , ZHAO YU-FEN
Published: November 2007

The reactions between nitrile oxides and alkenes are of considerable interest in organic synthesis as the resulting heterocycles are versatile intermediates for the synthesis of natural products and biologically active compounds. In this paper, we design a series of reactions of phosphonyl nitrile oxides with acrylonnitrile, which can give 2:1 cycloaddition products with no crystal structure released so far, and present a detailed theoretical study on the mechanism of the 2:1 1, 3-dipolar cycloaddition reaction, which has been explored with density functional theory calculations at B3LYP/6-31G* level. The results reveal that the following mechanism is quite possible. Firstly, it starts as a normal 1,3-dipolar cycloaddition reaction to produce a regiospecific 1:1 product. Subsequently, highly reactive diisopropanyl phosphonyl nitrile oxide sequentially reacts with the aforementioned regiospecific 1:1 product and gives the corresponding cycloadduct. Further study is underway to expand the scope of this methodology, as well as to ascertain mechanistic details of the cycloaddition process.
A Case-Control Study of the Environmental Risk Factors for Narcolepsy
Authors: Picchioni Dante , Hope Chris R. , Harsh John R.
Published: November 2007

Background: Despite the acknowledged importance of environmental risk factors in the etiology of narcolepsy, there is little research on this topic. This study sought to fill this gap in the literature and assess the risk of stressors and infectious diseases using a case-control study. Methods: Cases (n = 63) were recruited through the Stanford Center for Narcolepsy. All were HLA-DQB1*0602 positive, met conventional Multiple Sleep Latency Test criteria, and reported unambiguous cataplexy. Controls (n = 63) were nonrelated family members of cases and local community members. A self-administered questionnaire was used to assess the frequency and timing of possible risk factors. Results: Of the infectious diseases examined, only flu infections and unexplained fevers carried a significant risk. Several of the stressors carried a significant risk including a major change in sleeping habits. When the timing of all risk factors was considered, exposure prior to puberty increased the risk for developing narcolepsy. Conclusions: These findings emphasize the importance of environmental risk factors in the etiology of narcolepsy. This highlights the need for further research on this aspect of narcolepsy so a complete understanding of a disorder that affects 1 in 2,000 individuals can emerge.
Dentine Remineralisation by Simulated Saliva Formulations with Different Ca and Pi Contents
Authors: Hara A.T. , Karlinsey R.L. , Zero D.T.
Published: November 2007

The understanding of the dentine remineralisation process and the ability to reproduce it in vitro are essential to the development of preventive and therapeutic measures. This study investigated how simulated saliva formulations with different Ca and Pi contents and degrees of saturation with respect to biologically relevant calcium phosphates may affect the remineralisation of eroded dentine, as a function of time. Slabs of bovine root dentine (n = 8 per group) were flattened, polished, demineralised by 1% citric acid for 30 and 60 min and remineralised for 3, 7 and 14 days, by one of the following buffered (pH 7) solutions [Ca:Pi ratio, Ca/Pi concentrations (mM), ionic strength]: solution A: 1.6, 1.5/0.9, 0.115; solution B: 1.6, 2/1.25, 0.117; solution C: 1.6, 3.2/2, 0.121; solution D: 0.3, 1.11/3.7, 0.118; solution E: 0.3, 1.45/5, 0.122. Integrated mineral loss (30 and 60 min) was quantified by transverse microradiography after each remineralisation period. ANOVA and regression analyses (α = 0.05) showed, irrespective of the demineralisation time, that the solutions C and E were able to remineralise dentine. This effect increased throughout the remineralisation times and was significantly higher for E. Remineralisation was successfully shown in vitro, under specific conditions of degree of saturation and Ca and Pi contents of the solutions. Optimum remineralisation was observed for the solution E supersaturated with respect to relevant calcium phosphates, with low Ca:Pi ratio and highest Pi concentration.
Can Common-Type Atrial Flutter Be a Sign of an Arrhythmogenic Substrate in Paroxysmal Atrial Fibrillation?
Authors: Moreira Wendel , Timmermans Carl , Wellens Hein J.J. , Mizusawa Yuka , Philippens Suzanne , Perez David , Rodriguez Luz-Maria
Published: November 2007

Background—

The coexistence of atrial fibrillation (AF) and atrial flutter (AFL) is well recognized. AF precedes the onset of AFL in almost all instances. We evaluated the effect of 2 ablation strategies in patients with paroxysmal AF (PAF) and AFL.

Methods and Results—

Ninety-eight patients with PAF/AFL were prospectively recruited to undergo pulmonary vein cryoisolation (PVI). Those with at least 1 episode of sustained common-type AFL were assigned to cavotricuspid isthmus cryoablation followed by a 6-week monitoring period and a subsequent PVI (n=36; group I). Patients with PAF only underwent PVI (n=62; group II). The study included 76 men with a mean age of 50±10 years. Most patients (76 [78%]) had no structural heart disease. When the 2 groups were compared, residual AF after a blanking period of 3 months after PVI occurred in 24 patients (67%) in group I versus 7 (11%) in group II (
P
<0.05).

Conclusions—

In patients with PAF and no documented common-type AFL, PVI alone prevented the occurrence of AF in 82%, whereas in patients with AFL/PAF, cavotricuspid isthmus cryoablation and PVI were used successfully to treat sustained common-type AFL but appeared to be insufficient to prevent recurrences of AF. In this population, AFL can be a sign that non–pulmonary vein triggers are the culprit behind AF or that sufficient electrical remodeling has already occurred in both atria, and thus a strategy that includes substrate modification may be required.
Self-Efficacy for Self-Regulated Learning
Authors: Usher Ellen L. , Pajares Frank
Published: November 2007

The psychometric properties and multigroup measurement invariance of scores on the Self-Efficacy for Self-Regulated Learning Scale taken from Bandura's Children's Self-Efficacy Scale were assessed in a sample of 3,760 students from Grades 4 to 11. Latent means differences were also examined by gender and school level. Results reveal a unidimensional construct with equivalent factor pattern coefficients for boys and girls and for students in elementary, middle, and high school. Elementary school students report higher self-efficacy for self-regulated learning than do students in middle and high school. The latent factor is related to self-efficacy, self-concept, task goal orientation, apprehension, and achievement.
Pretreatment of Bleached Cotton Fibers with Whole and Monocomponent Cellulases for Nonwoven Applications
Authors: Arumugam Karthik , Verenich Svetlana , Shim Eunkyang , Pourdeyhimi Behnam
Published: November 2007

Enzymatic treatment of fabrics has been carried out in the past to enhance the aesthetic properties, which has often resulted in the reduction of fabric strength. The objective of the current investigation was to develop process recipes for the production of soft and strong nonwoven fabric from enzymatically treated cotton fibers. Two different enzymatic solutions, the whole cellulase and Cellulose Binding Domain (CBD)-free monocomponent endoglucanase, were selected for this purpose. The latter was used as potential enzyme solution that could reduce the fiber strength loss during hydrolysis. This paper discusses the changes in reducing power, protein adsorption, surface properties and single fiber tenacity of bleached cotton fibers and compares with those obtained with raw cotton treated at identical conditions. The results observed in this study showed that bleached cotton was less susceptible to damage and weakening than raw cotton fibers. Thus, the aggressive whole cellulase is more suitable for treatment of bleached cotton fibers, whereas CBDfree endoglucanase is sufficient for treatment of raw cotton fibers.
The development and implementation of MAID: a knowledge based support system for use in control system design
Authors: Boyle J.-M. , Pang G.K.H. , MaeFarlane A.G.J.
Published: November 2007

The development of a Knowledge Based System (KBS) that can assist a designer in performing advanced multivariable control system design is the central theme of this paper.

It starts by describing the role KBSs can play as designer's assistants. Then it is argued that the goal of developing a KBS can lead to a detailed analysis, and hence reformulation, of the essential design theory. The main body of the paper gives a description of how complex design concepts and strategies can be described and organised into a knowledge base. As the title suggests, this paper focuses on the actual implementation of a prototype KBS for control design: MAID. An example of a design session is included.
Applications of two-variable microwave techniques to composition analysis problems
Authors: Kent M.
Published: November 2007

Measurement of two microwave variables can be a useful technique for the determination of one compositional variable in the presence of another, uncontrolled, variable. Examples are given of methods for moisture and density, moisture and fat, and concentration and temperature of aqueous solutions. Many other examples can be found for which the technique is applicable.
A low-cost software correlator based on a new polarity correlation algorithm
Authors: Harba M.I.A. , Said S.M.
Published: November 2007

A new software correlator for polarity correlation estimation is presented. This correlator achieves a high sampling rate by block sampling, which makes it possible to store the signal samples in the individual bits of the microprocessor memory locations, so reducing the overall memory requirements of the correlator. The computational efficiency of the algorithm is derived from the ability of microprocessors to process complete bytes of data simultaneously. This correlator is implemented on a standard 8-bit microprocessor.

The algorithm used makes this correlator superior to other software correlators, including the zero-crossing correlator. The latter is, perhaps, the fastest software correlator available. It will be shown that for practical values of sampling rates, the new correlator is more economic in terms of signal storage, faster in terms of time of execution and has an operational bandwidth an order of magnitude higher than that of the zero-crossing correlator.
Multi-dimensional, sample data system stability
Authors: Whalley R.
Published: November 2007

This paper is focused on relative stability tests and their use in the design and analysis of multi-dimensional dynamical systems. General results are outlined, and specific examples dealing with the graphical procedures enabling two-dimensional sample data system analysis are presented.
Identification and performance simulation of a hybrid i.c.-engine/battery electric automotive power train. Part 2: The electric traction system
Authors: Masding P.W. , Bumby J.R.
Published: November 2007

This paper, and its companion, describe the identification, modelling and simulation of the drive-train components in a hybrid i.c.-enginelbattery electric car. This paper concentrates on the electric traction system and describes the identification of discrete transfer functions that relate motor current and motor shaft torque to the input demand to the power electronic controller. All the traction system transfer functions identified are related to a theoretical unalysis of the DC traction system and both full- and reduced-order models are derived. In the identification procedure the non-linear gains are identified separately to the system dynamics which leads to system transfer functions that are ideally suited for controller design. It is shown thut the power electronic controller has three distinct operating modes, and transfer functions are identified for each mode. Simulated results are compared with test data and the identified transfer functions shown to describe the behaviour of the electric traction system accurately. A method to predict motor torque by measuring armature current and field current is also presented. With the identified system transfer functions it is possible to design a control unit which will control the torque from the electric traction motor in a smooth manner.
A self-tuning adaptive control implementation by using a transputer-based parallel architecture
Authors: Fortuna L. , Gallo A. , Nunnari G.
Published: November 2007

In this paper the implementation of a self-tuning regulator, by using a mixed architecture based on a transputer network and DSP devices with transversal filter structure, is proposed. The hardware and software considered open new perspectives in the realisation of adaptive strategies for controlling a wide range of systems. The particular solution in implementation of the control algorithm is discussed in detail. Various applications are reported showing both the remarkable flexibility of the parallel architecture and the performances of the regulator. The proposed configuration allows us to control systems characterised by fast dynamics at a low cost and with reliable hardware support.
A method of quantitative validation based on model distortion
Authors: Butterfield M.H.
Published: November 2007

Traditional validation of mathematical models by visual comparison between recorded values and model calculations is regarded as too lenient. The distortion method described provides a practical quantitative validation procedure, in which the distortion that the model must undergo to match a rig or plant test record precisely is used to gauge the model. A numerical fidelity index has been derived.
Stability of non-linear control systems: the 'impulse-momentum' method
Authors: Fendrich O.R.
Published: November 2007

The 'impulse-momentum' method for predicting limit cycles was originally applied only to mechanical servomechanisms. This paper makes the method more general and extends it to the prediction of limit cycle stability in the absence of limit cycles. The predictions are compared with the results of analogue simulation.
Real-time electrical impedance imaging
Authors: Smith R.W.M. , Brown B.H. , Freeston I.L. , McArdle F.J.
Published: November 2007

This paper describes a medical imaging technique, called Electrical-Impedance Tomography. It then considers those applications in which a real-time EIT system would be useful. A design for such a system is presented, highlighting those areas that are critical in a real-time application.
Control systems robustness and its measurement
Authors: Jaworska I. , Finkelstein L.
Published: November 2007

This paper deals with the robustness problem of control systems; some robust stability measures in time and frequency models representations are quoted and their practical usefulness is discussed from the point of view of measurement theory.
Optimal tool setting for a machining centre
Authors: Pyle E.A.
Published: November 2007

This paper considers the task of an optimal tools setting for a machining centre (MC) to allow a reduction in time spent in the resetting of tools from one batch of workpieces to another. A theoretical relationship drafted is in full agreement with findings gained as a result of analysis of some 15 000 workpieces. A three-dimensional representation of an optimal tools setting is offered. A definition of an optimal tools setting is given, valid for any type of machine-tool.
Design of robust LQG optimal systems using partial loop transfer recovery
Authors: Grimble M.J.
Published: November 2007

It is shown that for systems which have an input subsystem, with outputs that can be observed, full LQR state-feedback robustness properties can be recovered at the input by only performing the recovery procedure on that section of the Kalman filter representing this subsystem. This has the advantage that the performance of the Kalman filter will not deteriorate as much as when using the full recovery procedure of Doyle and Stein. A procedure is also described for improving the measurement noise rejection properties of the Kalman filter when the recovery procedure is employed. This entails adding a fictitious coloured measurement noise source, allowing the frequency response of the filter to be shaped outside the recovery region. The problem was motivated by marine control problems where input subsystem measurements were accessible.
Multi-fibre calibration of incoherent optical fibre bundles for image transmission
Authors: Tsai M.J. , Smith J.S. , Lucas J.
Published: November 2007

This paper presents a multi-fibre illumination technique for automatically calibrating incoherent optical fibre bundles to enable the transmission of optical images. The calibration system consists of a host computer, a T414 Transputer board, a dedicated calibration board, a CCD camera, two TV monitors, and an incoherent optical fibre bundle. Multiple light spots produced on the screen of a TV monitor are used as a light source to illuminate simultaneously many input fibres in the bundle. The position of the corresponding output fibres can be found by capturing and analysing the image recorded by a CCD camera. Three incoherent optical fibre bundles with different resolutions have been calibratedusing this technique and verified by transmitting several different types of picture. The reconstructed image is achieved by means of a dedicated calibration board operating in nearly real time mode, i e within a delay time of one field period of 20 ms from the capture of the image. From the experimental results, the adequate transmission of images by an incoherent optical fibre bundle is clearly shown to be possible. The disadvantage of the long calibration time required by the single-fibre calibration method has been overcome by using this new technique.
Dynamical systems theory applied to management accounting: chaos in cost behaviour in a standard costing system setting
Authors: Tse N.S.F. , Robb F.F.
Published: November 2007

This Research Report draws the attention of control engineers to some of the results obtained from the application of chaos theory to modelling complex behaviour, The example chosen is a typical management accounting system in a manufacturing firm, and the model includes not only the formal control devices, but also the responses af the human operators, the managers, to the variance signals from that system.

Management accounting has become an eclectic discipline and so over time it has called upon a wide variety of methodologies to help to address its problems. It has, perhaps reluctantly, accepted the notion that statistical analysis and the assessment of probabilities can overcome, in part at least, the ambiguity of many managerial situations. It would be expected to be very eager to consider ways and means of reducing reliance on such methods and of increasing the explanaiory power of some of the tools already at its disposal within its own core discipline; for example, the setting of standards for budgetary control.

This paper reports recent research into the application of 'Dynamical Systems Theory'as a means of explaining apparently random cost behaviour in a standard cost context. It suggests that attention should be directed to the effects of different standard setting policies on the stability of the behaviour of managerial control systems.
A comparison between robust and adaptive hybrid position/force control schemes for hydraulic underwater manipulators
Authors: Lane D.M. , Dunnigan M.W. , Clegg A.C. , Dauchez P. , Cellier L.
Published: November 2007

Tele-operated hydrauilic underwater manipulators are commonly used to perform remote underwater intervention tasks such as weld inspection or mating of connectors Automation of these tasks to use tele-assitance requires a suitable hybrid position/force control scheme, to specify simultaneously the robot motion and contact forces. Classical linear control does not allow for the highly non-linear and time varying robot dynamics in this situation. Adequate control performance requires more advanced controllers. This paper presents and compares two different advanced hybrid control algorithms. The first is based on a modified Variable Structure Control (VSC-HF) with a virtual environment, and the second uses a multivariable self-tuning adaptive controller. A direct comparison of the two proposed control schemes is performed in simulation, using a model of the dynamics of a hydraulic underwater manipulator (a Slingsby TA9) in contact with a surface. These comparisons look at the performance of the controllers under a wide variety of operating conditions, including different environment stiffnesses, positions of the robot and dynamic parameters. Conclusions are drawn based on the relative performance of each controller and on the practicalities of the proposed schemes.
A new design and performance -test strategy for sigma-delta modulators
Authors: Zikic A.M. , Cheshmehdoost R.
Published: November 2007

The paper proposes a new approach to sigma-delta modulator design based on linear and non-linear control theories combined with a number of digital signal processing techniques. The limitations single-stage high-order designs are analysed as a compatibility problem between the linear filtering and non-linear quantiser requirements. The comnplexity versus performance-improvements of other strategies are also discussed. In addition to the new approach to component-compatibility analysis, the paper proposes a more rigorous analyses of the system performance by using, for the first time, groups of harmonic-rich test signals. Based on this new approach and the extensive analysis of how jointly and severally the linear and non-linear parameters influence the modulator's performance, a new design strategy is proposed and results demonstrated on a single-stage second-order modulator. The results are compared with those of an already-published second-order design for low over-sampling ratio of 64. It is shown that under the same conditions the new modulator exhibits a significantly improved signial-to-noise-ratio response' over a wide dynamic range of input signals. Finally, the conclusion discusses how this approach can be extendecl to other designs as well as used as a framework to completeyl new adaptive strategies.
Adaptive neural network approach to on-line learning for process fault diagnosis
Authors: Gomm J.B.
Published: November 2007

The practical difficulties of collecting representative fault data for network training can result in performance limitations when a trained static neural network is imple mented on-line for fault diagnosis of dynamic processes. To address this problem, an adaptive neural network is described that continually monitors and improves its performance on-line as new fault information becomes available. New nodes are automatically added to the network to accommodate new process faults after detec tion, and on-line adaptation is achieved using recursive linear algorithms to train selected network parameters. Applications of the adaptive neural network to the detection and diagnosis of incipient faults in a simulated chemical process and a real laboratory process rig are described. Results are presented to illustrate the network operation and demonstrate the ability of the network to learn and diagnose a range of process faults successfully.
Development of sensor arrays for electromagnetic inductive tomography: compensation of large background signal values
Authors: Yu Z.Z. , Peyton A.J.
Published: November 2007

A new electromagnetic inductance tomography (EMT) system has been developed with 16 excitation coils, 16 detection coils and a circular cross-section region of interest. This paper highlights one aspect of the sensor design, the compensation of the largest empty space signal. The system is capable of resolving a conductive or ferromagnetic object positioned in the centre with a diameter which is approximately 5% of that of the region of interest. This resolution is comparable to other electrical tomographic techniques. A description of the sensor array and a selection of sensitivity maps are also presented.
The design of a real-time engineering flight simulator for the rapid prototyping of avionics systems and flight control systems
Authors: Allerton D.J.
Published: November 2007

This paper describes the design of a real-time flight simulator, which is based on a modular architecture of PCs coupled by Ethernet. The simulator is required to provide a rapid prototyping environment to support the design and evaluation of avionics systems and flight control systems. Methods are described to ensure real-time implementation of the equations of motions using a standard PC and the provision of real-time graphics to simulate aircraft displays using SVGA. The paper includes analysis of the performance of the flight modelling methods and the simulation of aircraft displays. The paper concludes that high fidelity flight models and aircraft displays can be implemented using standard PC platforms and Ethernet cards, if attention is given to the design of the simulator architecture. The resultant simulator provides a rapid prototyping environment, standardising on the packet format and low-level packet protocols of Ethernet,
The acquisition of parameterized grammars
Authors: White Lydia
Published: November 2007

In this paper, I look at some problems that arise if second language learners are assumed to acquire the L2 on the basis of unconstrained hypothesis testing, since this crucially involves the assumption of the availability of negative evidence and does not seem to be sufficiently 'fine-tuned' for the learner to acquire certain aspects of the L2 grammar. Instead, it is proposed that L2 acquisition, like L1, may involve the prior knowledge of a number of highly contrained principles of Universal Grammar which restrict the number of options available to the learner. In some cases, these principles may be subject to parametric variation, so that they do not work in identical fashion in L1 and L2, allowing for the possibility of transfer of the L1 parameter setting. Taking subjacency as a case in point, a pilot study is reported in which native speakers of French and Spanish learning English as a second language were tested for their judgements on the bounding status of S in the L2 grammar. In English S is a bounding node, whereas in French and Spanish it is not. It was found that subjects were less accurate in their judgements on the bounding status of S in English than native-speaking controls, with a number of subjects consistently transferring the L1 parameter. In most cases, subjects showed improvement with increasing level of ESL proficiency. The majority of subjects adopted a consistent position with respect to the question of the bounding status of S, suggesting that they were not indulging in unconstrained hypothesis testing.
Interlanguage and the pro-drop parameter
Authors: Hilles Sharon
Published: November 2007

There is a relatively stable period in child L 1 acquisition during which surface subjects can be omitted. This period is also characterized by the absence of modals and expletives. With the emergence of modals and expletives, absent subjects disappear. This sequence has been attributed to the constraints of Universal Grammar (UG), a parameterized system with various settings depending on the language. The same sequence has also been observed in the interlanguage of a Spanish speaker learning English, suggesting that UG might also constrain interlanguages, and that a major part of L2 learning may be resetting the values of UG parameters.
Paragoge and degree of foreign accent in Brazilian English
Authors: Major Roy C.
Published: November 2007

This study examined global foreign accent in the English of 53 native speakers of Brazilian Portuguese and a specific measure of segmental articulation: errors due to transfer and developmental factors. The findings were: 1) the frequency of total errors was positively correlated with degree of foreign accent, 2) the frequency of developmental errors was greater than transfer errors, 3) as degree of foreign accent decreased, the frequency of transfer errors decreased more rapidly than developmental errors, 4) the frequency of total errors and the ratio of the two types of errors varied with the speaking task. The results of this study pertain to the question of whether transfer processes or developmental processes disappear more rapidly during the course of L2 acquisition.
The formal representation of words in an L2 speaker's lexicon
Authors: Meara Paul , Ingle Stephen
Published: November 2007

This paper reports an analysis of errors made by English-speaking learners of French. Forty learners learned a set of French words, and were subsequently tested in their ability to produce a correct phonetic form for these words. Nearly two-thirds of the attempts were incorrect, but a detailed analysis of these incorrect forms showed that not all parts of the target form were equally liable to error. Initial consonants are particularly stable, while subsequent parts of words are not reliably recalled. These results share some similarities with studies of slips of the tongue in English.
Research methodology in contextually- based second language research
Authors: Selinker Larry , Douglas Dan
Published: November 2007

We suggest a combined research methodology for studying SLA in real-life and important contexts, a methodology sensitive to the demands of such contexts. For studying IL learning in context, our suggested methodology combines and integrates aspects from three fields: grounded ethnography in ethnomethodol ogy ; subject-specialist informant procedures in language for specific purposes; and rhetorical/grammatical strategies in discourse analysis. We first present evidence for the importance of devising a research approach to contexually based SLA. Then we sketch the suggested research methodology and present two extended case studies which illustrate the methodology. We view such research as complimentary to universal approaches to core IL grammar. Finally, we sketch our theoretical approach, showing a possible link between research in universal and contextually-based SLA.
The poverty-of-the-stimulus argument and multicompetence
Authors: Cook V.J.
Published: November 2007

This paper examines the consequences of the fact that human minds may know more than one language for the poverty-of-the-stimulus argument that speakers know more than they could have learnt. Qualifications to the argument are necessary because not all L2 learners attain the same compe tence as L1 speakers; types of evidence are potentially available that can be ruled out for the Ll. The way in which L2 learning has been concep tualized in terms of access to UG and of a black box metaphor makes the L2 grammar seem separate from the L1 grammar rather than one over all system contained within a single mind. What is needed is the idea of 'multicompetence' - the compound state of a mind with two grammars. Multicompetence is the norm for the human race in that most minds know more than one language. Hence the logical problem of language acquisition is how the mind acquires a grammar with one or more settings for each parameter, rather than the special case of a mind that knows only one language. This has implications for all uses of the poverty-of-the-stimulus argument, not just in L2 learning.
Adverb placement in second language acquisition: some effects of positive and negative evidence in the classroom
Authors: White Lydia
Published: November 2007

This paper focuses on a parametric difference between French and English, namely the issue of whether or not the language allows verb movement. The lack of verb-raising in English causes a potential learnability problem for francophones, as far as English adverb placement is concerned. In particular, an adverb in English is not allowed to interrupt a verb and its direct object, in contrast to French. It is argued in this paper that form-focused classroom instruction, including negative evidence, is more effective in helping L2 learners to arrive at the appropriate properties of English than positive input alone. An experimental study on the effectiveness of teaching adverb placement was conducted with I 1 and 12 year-old francophone learners of English. One group (n = 82) was explicitly instructed on adverb placement, and another on ques tion formation (n = 56). Subjects were tested on a variety of tasks relating to adverb placement; they were pretested, and post-tested twice, immediately after the instructional period, and again five weeks later. Some of the subjects were followed up a year after the original testing. Results show significant differences between the two groups: only the group that received positive and negative evidence that was specifically oriented towards adverb placement came to know that adverbs may not interrupt the verb and object. The results from the follow up, however, suggest that this knowledge is not retained in the long-term.
Variable competence and performance in child second language acquisition1
Authors: Flanigan Beverly Olson
Published: November 2007

The variable competence model of second language acquisition proposes that the ability to use language varies systematically within functional domains and linguistic contexts, and that such variability is inherent in interlanguage as well. This study of elicited and naturalistic speech of elementary school ESL students in formal and informal situations supports the conclusion that variability exists in the acquisition process but disputes the theory that it is a necessary com ponent of the mental competence itself. Errors in use of the past tense, noun phrase plurals and possessives, adjectives, and determiners were calculated for four different activities or tasks; t-tests and regression analyses revealed little or no statistical difference across tasks but predictable differences with increase in proficiency. Implications are drawn for the teaching of grammar to children in an academic context.