bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual processing of derivational morphology in children with developmental dyslexia: Insights from masked priming
Authors: QUÉMART PAULINE , CASALIS SÉVERINE
Published: May 2013

We investigated whether children with dyslexia rely on derivational morphology during visual word recognition and how the semantic and form properties of morphemes influence this processing. We conducted two masked priming experiments, in which we manipulated the semantic overlap (Experiment 1) and the form overlap (Experiment 2) between morphologically related pairs of words. In each experiment, French dyslexic readers as well as reading-level matched and chronological-age matched children performed a lexical decision task. Significant priming effects were observed in all groups, indicating that their lexicon is organized around morpheme units. Furthermore, the dyslexics’ processing of written morphology is mainly influenced by the semantic properties of morphemes, whereas children from the two control groups are mainly influenced by their form properties.
Feeling in control: comparing older people's experiences in different care settings
Authors: CALLAGHAN LISA , TOWERS ANN-MARIE
Published: May 2013

The promotion of choice and control for older people is a policy priority for social care services in the United Kingdom and is at the heart of recent drives to personalise services. Increasingly, we are seeing a move away from institutionalised care (e.g. in care homes) towards enablement, with more services being delivered in community-based settings. Extra care housing has been promoted as a purpose-built, community-based alternative to residential care for older people. However, whilst accounts of users' experiences in particular service types are plentiful, the use of different instrumentation and measures makes comparison between settings difficult. We combined data from four studies where participants were older people either living in care homes or extra care housing or receiving care at home. All of these studies asked participants to rate their control over daily life, using the Adult Social Care Outcomes Toolkit (ASCOT). This paper presents the results of an ordinal logistic regression analysis indicating that, after controlling for differences in age, ability to perform activities of daily living and self-rated health, setting had a significant effect on older people's sense of control. Residents in care homes and extra care housing report similar levels of control over daily life but consistently report feeling more in control than older people receiving care at home. Implications for policy and practice are discussed.
Imperfect sound forever: loudness wars, listening formations and the history of sound reproduction
Authors: Devine Kyle
Published: May 2013

The purpose of this paper is to provide some historical perspective on the so-called loudness war. Critics of the loudness war maintain that the average volume level of popular music recordings has increased dramatically since the proliferation of digital technology in the 1980s, and that this increase has had detrimental effects on sound quality and the listening experience. My point is not to weigh in on this debate, but to suggest that the issue of loudness in sound recording and playback can be traced back much earlier than the 1980s. In fact, loudness has been a source of pleasure, a target of criticism, and an engine of technological change since the very earliest days of commercial sound reproduction. Looking at the period between the turn-of-the-century format feud and the arrival of electrical amplification in the 1920s, I situate the loudness war within a longer historical trajectory, and demonstrate a variety of ways in which loudness and volume have been controversial issues in – and constitutive elements of – the history of sound reproduction. I suggest that the loudness war can be understood in relation to a broader cultural history of volume.
Locating the canon in Tamworth: historical narratives, cultural memory and Australia's ‘Country Music Capital’
Authors: Baker Sarah , Huber Alison
Published: May 2013

This article concerns the regional city of Tamworth, New South Wales, Australia, a place that prides itself on its reputation as Australia's home of country music. We consider the ongoing memorialisation of country music in Tamworth, and how the processes associated with the project of articulating country music's past work to create and maintain something that can be recognised (and experienced) as a dominant narrative or an Australian country music ‘canon’. Outlining a number of instances in which the canon is produced and experienced (including in performances, rolls of honour and monuments built around the city), the article explores the ways in which this narrativisation of Australia's country music history contributes to a certain kind of memory of the genre's past.
Black beats with a Punjabi twist
Authors: Roy Anjali Gera
Published: May 2013

The bonding between black and brown immigrants in Britain has resulted in the emergence of a new musical genre called Bhangra, which hybridises Punjabi dhol rhythms with those of reggae, rap and hip hop. Bhangra's appropriation of Black sounds that are considered ‘Kool’ in the West has not only given Asian youth a new, distinctive voice in the form of ‘Asian dance music’ but has also led to the reinvention of Punjabi folk tradition in consonance with the lived realities of multicultural Britain. This essay examines various aspects of sonic hybridisation in ‘the diaspora space’ by British Asian music producers through tracing the history of Bhangra's ‘douglarisation’, beginning in the 1990s with Apache Indian's experiments with reggae. It covers all forms of mixings that came in between, including active collaborations, rappings, remixings, samplings and so on that made Punjabi and Jamaican patois dialogue in the global popular cultural space. The essay explores the possibilities of a ‘douglas poetics’ for Bhangra by juxtaposing the celebration of sonic douglarisation in postmodern narratives of migrancy and hybridity against the stigmatisation of biological douglarisation in miscegenation theories and ancient Indian pollution taboos.
Internet-Delivered Cognitive Therapy for Social Anxiety Disorder: A Development Pilot Series
Authors: Stott Richard , Wild Jennifer , Grey Nick , Liness Sheena , Warnock-Parkes Emma , Commins Siobhan , Readings Jennifer , Bremner Georgina , Woodward Elizabeth , Ehlers Anke , Clark David M.
Published: May 2013

Background: Randomized controlled trials have established that individual cognitive therapy based on the Clark and Wells (1995) model is an effective treatment for social anxiety disorder that is superior to a range of alternative psychological and pharmacological interventions. Normally the treatment involves up to 14 weekly face-to-face therapy sessions. Aim: To develop an internet based version of the treatment that requires less therapist time. Method: An internet-delivered version of cognitive therapy (iCT) for social anxiety disorder is described. The internet-version implements all key features of the face-to-face treatment; including video feedback, attention training, behavioural experiments, and memory focused techniques. Therapist support is via a built-in secure messaging system and by brief telephone calls. A cohort of 11 patients meeting DSM-IV criteria for social anxiety disorder worked through the programme and were assessed at pretreatment and posttreatment. Results: No patients dropped out. Improvements in social anxiety and related process variables were within the range of those observed in randomized controlled trials of face-to-face CT. Nine patients (82%) were classified as treatment responders and seven (64%) achieved remission status. Therapist time per patient was only 20% of that in face-to-face CT. Conclusions: iCT shows promise as a way of reducing therapist time without compromising efficacy. Further evaluation of iCT is ongoing.
Inkjet-printed paper-based substrate-integrated waveguide (SIW) components and antennas
Authors: Moro Riccardo , Kim Sangkil , Bozzi Maurizio , Tentzeris Manos
Published: May 2013

This paper presents a novel technology for the implementation of substrate-integrated waveguide (SIW) structures, based on a paper substrate and realized by an inkjet-printing fabrication process. The use of paper permits to implement low-cost microwave structures and components, by adopting a completely eco-friendly implementation technology. SIW structures appear particularly suitable for implementation on paper, due to the possibility to easily realize multilayered topologies and conformal geometries. In this paper, SIW passive components, and antennas (including straight interconnects, band-pass filters, and slotted-waveguide antennas) are proposed for the first time. The design of the components, the steps of the fabrication process, and the experimental characterization of the prototypes are reported in this paper.
Evidence and Deployment-Based Research into Care for the Elderly Using Emotional Robots
Authors: Kolling Thorsten , Haberstroh Julia , Kaspar Roman , Pantel Johannes , Oswald Frank , Knopf Monika
Published: May 2013

Global aging, particularly in Japan and Europe, an associated shortage of qualified healthcare personnel, and a general preference for living at home, have all sparked an interest in the possibilities offered by robot therapy in improving quality of life. To date, however, both evidence-based research and psychological theory building on whether, and if so how and why, robots can influence the life of the elderly are rather sparse and scattered across many scientific disciplines and countries. The present paper argues in favor of a psychological, cross-cultural framework for evidence-based analyses of emotional robots. Against the background of this framework, we present building blocks for an evidence-based approach to the assessment of emotional robots and discuss interactions between evidence- and deployment-based research.
Modeling cell-in-cell structure into its biological significance
Authors: He M-f , Wang S , Wang Y , Wang X-n
Published: May 2013

Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ‘entering’ and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintaining homeostasis, aberrant cell-in-cell process contributes to the etiopathology in humans. Indeed, cell-in-cell is observed in many pathological processes of human diseases. In this review, we intend to discuss the biological models of cell-in-cell structures under physiological and pathological status.
A design-constraint trade-off underpins the diversity in ecologically important traits in species Escherichia coli
Authors: Phan Katherine , Ferenci Thomas
Published: May 2013

Bacterial species are internally diverse in genomic and multi-locus gene comparisons. The ecological causes of phenotypic and genotypic diversity within species are far less well understood. Here, we focus on the competitive fitness for growth on nutrients within Escherichia coli, an internally rich species. Competition experiments in nutrient-limited chemostats revealed that members of the ECOR collection exhibited a wide continuum of competitive abilities, with some fitter and some less fit than the lab strain MG1655. We observed an inverse relationship between competitiveness and the resistance of strains to detergent and antibiotic, consistent with the notion that membrane permeability and competitive fitness are linked by a trade-off between self-preservation and nutritional competence (SPANC); high permeability has a postulated cost in antibacterial sensitivity whereas a low permeability has a cost in nutrient affinity. Isolates moved along the markedly nonlinear trade-off curve by mutational adaptation; an ECOR strain sensitive to antibacterials and a good competitor was easily converted by mutation into a mutant with higher resistance but poorer competition in the presence of low antibiotic concentrations. Conversely, a resistant ECOR strain changed into a better competitor after a short period of selection under nutrient limitation. In both directions, mutations can affect porin proteins and outer membrane permeability, as indicated by protein analysis, gene sequencing and an independent assay of outer membrane permeability. The extensive, species-wide diversity of E. coli in ecologically important traits can thus be explained as an evolutionary consequence of a SPANC trade-off driven by antagonistic pleiotropy.
Citizen Science Provides Valuable Data for Monitoring Global Night Sky Luminance
Authors: Kyba Christopher C. M. , Wagner Janna M. , Kuechly Helga U. , Walker Constance E. , Elvidge Christopher D. , Falchi Fabio , Ruhtz Thomas , Fischer Jürgen , Hölker Franz
Published: May 2013

The skyglow produced by artificial lights at night is one of the most dramatic anthropogenic modifications of Earth's biosphere. The GLOBE at Night citizen science project allows individual observers to quantify skyglow using star maps showing different levels of light pollution. We show that aggregated GLOBE at Night data depend strongly on artificial skyglow and could be used to track lighting changes worldwide. Naked eye time series can be expected to be very stable, due to the slow pace of human eye evolution. The standard deviation of an individual GLOBE at Night observation is found to be 1.2 stellar magnitudes. Zenith skyglow estimates from the “First World Atlas of Artificial Night Sky Brightness” are tested using a subset of the GLOBE at Night data. Although we find the World Atlas overestimates sky brightness in the very center of large cities, its predictions for Milky Way visibility are accurate.
Binary neighbourhood field optimisation for unit commitment problems
Authors: Wu Zhou , Chow Tommy W.S.
Published: May 2013

Inspired by the neighbourhood cooperation, a new discrete optimisation algorithm is proposed. The so‐called binary neighbourhood field optimisation (BNFO), utilises the attractive field of the superior neighbour and the repulsive field of the inferior neighbour. As a kind of local search, BNFO is able to deliver promising results efficiently within acceptable computational time. BNFO is applied to solve the unit commitment problem (UCP), whose objective is to minimise the operation cost of the generation units over the scheduling horizon. After numerical tests on several benchmark UCP cases, the obtained costs are less expensive compared with conventional Lagrangian relaxation, genetic algorithm, evolutionary programming, particle swarm optimisation and differential evolutionary. BNFO can converge to promising results with less computation times, especially for the large‐scale UCPs.
Hourly demand response in day‐ahead scheduling for managing the variability of renewable energy
Authors: Wu Hongyu , Shahidehpour Mohammad , Al‐Abdulwahab Ahmed
Published: May 2013

This study proposes a stochastic optimisation model for the day‐ahead scheduling in power systems, which incorporates the hourly demand response (DR) for managing the variability of renewable energy sources (RES). DR considers physical and operating constraints of the hourly demand for economic and reliability responses. The proposed stochastic day‐ahead scheduling algorithm considers random outages of system components and forecast errors for hourly loads and RES. The Monte Carlo simulation is applied to create stochastic security‐constrained unit commitment (SCUC) scenarios for the day‐ahead scheduling. A general‐purpose mixed‐integer linear problem software is employed to solve the stochastic SCUC problem. The numerical results demonstrate the benefits of applying DR to the proposed day‐ahead scheduling with variable RES.
OPEN unified power quality conditioner with control based on enhanced phase locked loop
Authors: Teke Ahmet , Meral Mehmet Emin , Cuma Mehmet Uğraş , Tümay Mehmet , Bayindir Kamil Çağatay
Published: May 2013

OPEN unified power quality conditioner (UPQC) offers different power quality levels with different electricity bill to their users. OPEN UPQC has more flexible modularity than traditional UPQC for field applications. OPEN UPQC consists of two controlled pulse‐width modulated shunt and series inverters that have no common DC link. Shunt inverter eliminates current harmonics originating from non‐linear load side and series inverter mitigates voltage sag/swell at the point of common coupling caused from faults on transmission system. In this study, controllers for both shunt and series inverters are based on enhanced phase locked loop (E‐PLL) and non‐linear adaptive filter. For the controller of shunt inverter, proportional integrator controller‐based DC‐link control strategy is adapted to E‐PLL. A fast sag/swell detection method is also presented. Functionalities of OPEN‐UPQC system is deeply analysed and tested through simulation studies with power system computer aided design/electromagnetic transients DC analysis program. The test results verify that OPEN UPQC achieves good performance for mitigating the effects of voltage sag/swell and suppressing the load current harmonics.
Effect of customer worth of interrupted supply on the optimal design of small isolated power systems with increased renewable energy penetration
Authors: Katsigiannis Yiannis A. , Georgilakis Pavlos S.
Published: May 2013

The analysis and design of a small isolated power system (SIPS) with renewable energy sources (RES) and storage can be challenging, because of the large number of design options and the uncertainty in key parameters. RES add further complexity because their power output may be intermittent, seasonal and non‐dispatchable. Owing to this characteristic, reliability evaluation of a RES‐based SIPS cannot be implemented using the traditional deterministic and analytical methods. Moreover, this evaluation has to be done within a cost‐benefit framework. This study models and investigates the effect of customer worth of interrupted supply (customer damage cost) on the optimal design of SIPS with storage and increased RES penetration. The SIPS optimal design is implemented with a genetic algorithm combined with local search procedure. In addition, this study examines the effect of the forced outage rate of SIPS components on SIPS optimal design via Monte Carlo simulation. The performance of the proposed hybrid optimisation methodology is investigated for a large number of alternative scenarios via sensitivity analysis, which study the effect on the results because of the uncertainty on weather data, components efficiency and cost data. The results show that the optimal design of a RES‐based SIPS depends largely on the consideration of customer damage cost as well as the inclusion of components forced outage rate. The method and results presented in this article should be valuable in planning and operating SIPS with RES.
Adaptive enumeration method for the optimal interconnection planning of isolated power systems
Authors: Loukarakis Emmanouil , Stavrakakis Georgios
Published: May 2013

The target of this work is the determination of the optimal solution in transmission expansion planning in the particular case of isolated systems involving dc interconnections. Therefore special attention is given to dc‐links modelling aspects for steady state analysis, as well as security constraints relevant to small sized systems operation. Therein lies the first contribution of this work, namely in the incorporation of operating reserve related considerations and simplified dc‐links models in isolated systems planning. The proposed method combines a Monte‐Carlo simulation, which enables the probabilistic assessment of power system operation, with an adaptive enumeration technique which recurrently determines and evaluates investment scenarios of interest, based on suitable probabilistic indices. This constitutes the second contribution of this work, as a map of all meaningful solutions to the planning problem may be generated, which in turn allows not only the determination of the optimal solution, but also the evaluation of the effects of over‐ or under‐investment in certain parts of the grid.
Transient stability constrained optimal power flow using independent dynamic simulation
Authors: Tu Xiaoping , Dessaint Louis‐A. , Nguyen‐Duc Huy
Published: May 2013

Transient stability constrained optimal power flow (TSC‐OPF) is originally a non‐linear optimisation problem with variables and constraints in time domain, which is not easy to deal with directly because of its huge dimension. This study presents an efficient approach to realise TSC‐OPF by introducing an independent dynamics simulation algorithm into the optimisation procedure. In the new approach, the simulation algorithm is used to realise the dynamics constraints and to deduce the transient stability constraint, whereas the optimisation algorithm verifies the steady state and the transient stability constraints together. The new TSC‐OPF has just one more constraint than that of a conventional OPF and can be solved by a conventional OPF algorithm with small modification. Moreover, the new approach makes it easy to improve the accuracy and efficiency of TSC‐OPF, because of its flexibility in choosing machine models and simulation methods, which is important for large power systems. In the study, the proposed approach is tested with two small power systems, where the two‐axis machine model and a mixed time step simulation method are used to assess system transient stability with a 1‐ms time resolution.
Is ICT mature for an EU‐wide Intelligent Transport System?
Authors: Pagano Paolo , Petracca Matteo , Alessandrelli Daniele , Salvadori Claudio
Published: May 2013

In this study, the general problem of scalable and inter‐operable Intelligent Transport Systems (ITSs) is addressed. Referring to a new proposal based on next generation networks promoting a pervasive, distributed and inter‐operable service‐oriented architecture, the authors comment on existing frontier technologies capable of deploying such systems. A new layered architecture for an EU‐wide ITS is shown against the state‐of‐the‐art ITS design; the presented solution is expected to overcome the actual limitations in pervasiveness of the collection layer and in virtualisation of users, connectivity, storage and calculus. The IPv6 global network (and especially the 6LoWPAN extension to embedded constrained devices), also delivered through wideband technologies, is seen as the enabling technology to support large‐scale ITS; moreover a proposal to explicitly consider distributed calculus and high capacity storage for data and computationally intensive applications is presented.
Calibrating car‐following parameters for snowy road conditions in the microscopic traffic simulator VISSIM
Authors: Asamer Johannes , van Zuylen Henk J. , Heilmann Bernhard
Published: May 2013

Calibrated simulation models taking into account adverse weather conditions can be used to optimise traffic management strategies, such as speed adaptation and signal timing optimisation. On snowy road conditions, car‐following behaviour changes because drivers tend to accelerate more slowly, increase their following distance and drive with lower speeds. Such changes results in lower saturation flow rates at intersections. In order to simulate traffic on snowy road conditions in a valid way, the parameters of a simulation have to be calibrated for adverse weather. This study identifies the parameters of the car‐following model in the microscopic simulator VISSIM that are sensitive to snowy road conditions and indicates valid parameter subspaces leading to a good match of simulation model output with observed saturation flow rates and start‐up delays. In combination with green time of a signalised intersection, saturation flow rate is essential for correctly estimating road capacity.
Reducing local traffic emissions at urban intersection using ITS countermeasures
Authors: Mahmod Mohamed , van Arem Bart , Pueboobpaphan Rattaphol , de Lange Ronald
Published: May 2013

In many countries traffic emissions have significantly increased during the last two decades because of the increased number of vehicles. As such, traffic emissions have become the main source of air pollution in urban areas, where breaches of the EU limit values frequently occur. To reduce these emissions, local traffic measures can be implemented complementary to regional and national measures. In this study, the impact of various traffic measures at a single intersection is investigated using a traffic model and an emission model. The measures included are traffic demand control, banning heavy duty vehicles (HDVs) and speed restriction. It was found that reducing traffic demand by 20% led to about 23% reduction in terms of CO2, NOx and PM10 emissions. Banning HDVs led to a significant reduction of NOx and PM10 emissions. Although speed restriction reduced both CO2 and NOx emissions by 16.1 and 13.4%, PM10 emissions increased by 19%, mainly from HDVs.
Telematics system for the intelligent transport and distribution of medicines
Authors: Garcia Zuazola Ignacio Julio , Moreno Asier , Landaluce Hugo , Angulo Ignacio , Perallos Asier , Hernández‐Jayo Unai , Sainz Nekane , Ziai Mohamed A. , Batchelor John C. , Elmirghani J.M.H.
Published: May 2013

A growing demand for well‐defined telematics systems in the intelligent transport distribution of pharmaceutical drugs is envisaged driven by legislative demands to enable the safe handling of medicines in automotive distributions. The provision is accomplished by providing virtual intelligence to vehicles designated for this form of smart freight transportation. The system provides anytime/anywhere assets tracking while on the move, from departure to destination, supporting reliable courier operation at low labour. The tracking and tracing system provides the vehicle with sufficient intelligence to: be located remotely, track and trace assets and provide incidence reports. The authors’ architecture is intended to automatically broadcast adaptive logistic‐distribution‐plans between a central office and a vehicle. The proposed system represents an inexpensive and non‐intrusive solution that exploits advanced technologies such as smart environment sensing, radio frequency identification, Wireless Fidelity (WiFi) and global positioning system, to support modern industrial needs. The authors describe and discuss the motivation and the beneﬁts of using the system, including new hardware and software developments.
Driver fatigue detection from electroencephalogram spectrum after electrooculography artefact removal
Authors: Hu Shuyan , Zheng Gangtie , Peters Björn
Published: May 2013

A driver fatigue monitoring and detection system with high accuracy could be a valuable countermeasure to decrease fatigue‐related traffic accidents. This study proposes methods for drowsiness detection based on electroencephalogram (EEG) power spectrum analysis. First, a new algorithm is proposed for independent component analysis with reference (ICA‐R) for electrooculography artefacts removal. Comparison is then carried out between the proposed ICA‐R algorithm and an adaptive filter. Secondly, 75 EEG spectrum features are extracted from the cleaned EEG. Among all the EEG spectrum‐related features, 40 key features are selected by support vector machine recursive feature elimination to improve the performance of the classifier. The validation results show that 86% of the driver's drowsiness states can be accurately detected among drivers, who participate a driving simulator study.
On optimal freeway local ramp metering using fuzzy logic control with particle swarm optimisation
Authors: Xu Jianxin , Zhao Xinjie , Srinivasan Dipti
Published: May 2013

In this study, the problem of optimal freeway local ramp metering is address by using fuzzy logic control (FLC)‐based ramp metering. The objective of optimal freeway local ramp metering is to minimise a weighted total‐time spent‐(WTTS)‐based cost function, which measures the performance of freeway local ramp metering in terms of the WTTS by vehicles on both the freeway mainstream and on‐ramp link. A simple and efficient local ramp metering algorithm based on Takagi–Sugeno type FLC algorithm is proposed. The input membership functions of the FLC controller are predefined, and human expert knowledge on freeway traffic flow behaviours is utilised to reduce the size of fuzzy rule base. The consequent parameters are fine‐tuned by particle swarm optimisation and microscopic traffic simulations. Simulation studies with PARAMICS traffic simulation platform show the potential of the proposed approach in obtaining the optimal freeway local ramp metering strategies to strike a balance between traffic conditions on the mainstream and the on‐ramp link.
Integrated higher‐order pulse‐width modulation filter–transformer structure for single‐phase static compensator
Authors: Venkatramanan D. , John Vinod
Published: May 2013

A power filter is necessary to connect the output of a power converter to the grid so as to reduce the harmonic distortion introduced in the line current and voltage by the power converter. Many a times, a transformer is also present before the point of common coupling. Magnetic components often constitute a significant part of the overall weight, size and cost of the grid interface scheme. So, a compact inexpensive design is desirable. A higher‐order LCL‐filter and a transformer are increasingly being considered for grid interconnection of the power converter. This study proposes a design method based on a three‐winding transformer, that generates an integrated structure that behaves as an LCL‐filter, with both the filter inductances and the transformer that are merged into a single electromagnetic component. The parameters of the transformer are derived analytically. It is shown that along with a filter capacitor, the transformer parameters provide the filtering action of an LCL‐filter. A single‐phase full‐bridge power converter is operated as a static compensator for performance evaluation of the integrated filter transformer. A resonant integrator‐based single‐phase phase locked loop and stationary frame AC current controller are employed for grid frequency synchronisation and line current control, respectively.
Block diagrams and transfer functions of control‐to‐output and line‐to‐output for peak current‐mode controlled boost converters
Authors: Chen Shen‐Yaur
Published: May 2013

This study presents a systematic multi‐loop block diagrams for the peak current‐mode controlled boost converter in order to investigate its intrinsic properties. Under low frequencies, the proposed block diagram of control‐to‐output can approximate the current loop of the converter to a current source. Furthermore, the block diagram of line‐to‐output clearly shows three forward paths affecting the AC voltage output. These block diagrams also make it possible to derive the control‐to‐output and line‐to‐output transfer functions. Finally, an actual boost circuit is provided and tested. From the experimental and simulation results, the proposed transfer functions are verified.
Thermal–electrical averaging model of resonant converters based on extended describing function method
Authors: Lv Jianxun , Cao Zhiyu , Fröhleke Norbert , Böcker Joachim , Yuan Haiwen , Mi Hanguang
Published: May 2013

Owing to limited computational resources and the very large difference between electrical and thermal time constants, simulation for resonantly operated DC–DC converters using physical or ideal switching model is very time‐consuming or impossible. In this contribution, a novel thermal–electrical averaging model of resonantly operated DC–DC converters is proposed to reduce the computational burden and time consumption. The thermal–electrical model is based on extended describing function method. All required parameters for the thermal model can be obtained from the datasheets or on the website. The thermal–electrical models are applied in series–parallel resonant converters with LC‐type and C‐type output filters as examples, and verified by comparison with two standard simulation tools. The thermal–electrical modelling procedure proposed in this contribution can of course also be applied for other types of resonant converters, such as series resonant converter, parallel resonant converter and multi‐phase resonant converter.
Quadratic step‐down dc–dc converters based on reduced redundant power processing approach
Authors: Loera‐Palomo Rodrigo , Morales‐Saldaña Jorge Alberto , Palacios‐Hernández Elvia
Published: May 2013

In the technical literature the interconnection of switching converters to increase power handling capabilities on dc applications has been widely reported. This study presents a family of switching step‐down dc–dc converters based on the principle of reduced redundant power processing (R2P2). This states that the power transfer from input port to output port on interconnected converters can be reduced, if a non‐cascading connection is used. As shown in this study, the principle R2P2 is useful for developing new converters. The resulting converters are formed by a pair of L–C networks and a pair of active switches, also they have wide conversion ratios and quadratic dependence with respect to the duty ratio. In this study, the voltage conversion ratios and steady‐state operating conditions are derived for the proposed converters, which are verified by experimental results.
Adaptive predictive current control technique for permanent magnet synchronous motors
Authors: Sozer Yilmaz , Torrey David A. , Mese Erkan
Published: May 2013

Producing the required magnitude and shape of reference current is necessary to achieve precise torque control in motor control applications. A deadbeat predictive current controller provides very good dynamic performance. In order to achieve very accurate reference current production, the machine and inverter should be modelled properly with accurate parameters. Parameter changes, especially the back electromagnetic force (bemf) voltages and inverter delay elements, cause deadbeat current regulator performance to deteriorate significantly. This study addresses accurate determination of permanent magnet synchronous machine parameters dynamically online, taking into account the delay elements such as inverter output filters, calculation time steps of the control algorithm within the digital signal processor (DSP) and updating the current regulation accordingly. The new algorithm is simulated and experimentally tested. The simulation and experimental results of the new current regulation technique provide very good dynamic and steady‐state results, validating regulator performance.
Single‐stage single‐switch power factor correction converter based on discontinuous capacitor voltage mode buck and flyback converters
Authors: Ramezan Ghanbari Alireza , Adib Ehsan , Farzanehfard Hosein
Published: May 2013

A new single‐switch, single‐stage power factor correction (PFC) converter based on discontinuous capacitor voltage mode (DCVM) is presented in this study. The conventional single‐stage PFC converters have high voltage across their bulk capacitor which imposes high voltage stress on the switch and also the bulk capacitor voltage stress increases at light load condition. The most important advantage of the proposed topology is that the voltage across the bulk capacitor is low and the input current is continuous. Furthermore, this topology does not have high voltage stress across the bulk capacitor at light loads. The proposed topology is derived from a DCVM buck converter integrated with a flyback converter. The proposed PFC topology contains low number of passive components and employs only one switch, resulting in reduced complexity and cost. The presented simulation and experimental results of the proposed converter justify the theoretical analysis.
Z‐source‐based isolated high step‐up converter
Authors: Evran Fatih , Aydemir Mehmet Timur
Published: May 2013

Continuous input currents and high step‐up ratios are desired from the dc–dc converters that work with renewable energy sources such as photovoltaic panels and fuel cells. Most dc–dc converters use transformers to have high step‐up ratios. There is another type of converters that use coupled inductors, but they need to operate at high duty cycles to increase the gain. These converters suffer from low efficiency values because of the leakage inductance values and long reverse recovery times of the diodes. A new dc–dc converter based on Z‐source topology is proposed in this study. It uses coupled inductors to increase the step‐up ratio. Its main features are high step‐up ratios, continuous input currents, high efficiency and galvanic isolation between input and output. Simulation and experimental results are given for a prototype converter that converts 25–400 V dc at 300 W with over 91% efficiency.
Mechanism and elimination of harmonic current injection from single‐phase grid‐connected PWM converters
Authors: Zhou Keliang , Qiu Zhipeng , Watson Neville R. , Liu Yonghe
Published: May 2013

The mechanism of harmonic current injection from single‐phase grid‐connected converters is comprehensively investigated. The measurable impacts from grid voltage, converter commutation, power factor, PWM modulation and control strategy are demonstrated on the harmonic current injection. According to the mechanism, a tailor‐made control solution which employs a low pass voltage‐loop filter and internal model principle‐based hybrid current controller, is proposed to eliminate the harmonic current injection from the single‐phase grid‐connected converters. Experiments are performed to verify the validity of the mechanism and the proposed control method. It not only presents an effective tailor‐made solution to the elimination of harmonic current injection from grid‐connected power converters, but also provides a mechanism‐based benchmark tool to further develop rational grid requirements on the harmonic injection levels in the grid integration of distributed generation units.
Study of a non‐isolated bidirectional DC–DC converter
Authors: Lin C.‐C. , Yang L.‐S. , Wu G.W.
Published: May 2013

The study presents a non‐isolated bidirectional DC–DC converter, which has simple circuit structure. The control strategy is easily implemented. Also, the synchronous rectifier technique is used to reduce the losses. The voltage gain of the proposed converter is the half and the double of the conventional bidirectional DC–DC buck/boost converter in the step‐down and step‐up modes, respectively. Therefore the proposed converter can be operated in wide‐voltage‐conversion range than the conventional bidirectional converter. The voltage stresses on the switches of the proposed converter are a half of the high‐voltage side. In addition, the operating principle and steady‐state analyses are discussed. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.
Space vector pulse‐width modulation algorithm and DC‐side voltage control strategy of three‐phase four‐switch active power filters
Authors: Wang Wen , Luo An , Xu Xianyong , Fang Lu , Chau Thuyen Minh , Li Zhou
Published: May 2013

A space vector pulse‐width modulation (SVPWM) algorithm and a DC‐side voltage control strategy for three‐phase four‐switch shunt active power filters are proposed. The basic principle of three‐phase four‐switch inverters to output three‐phase balanced voltages is investigated in detail. Based on an advanced coordinate transformation, the proposed algorithm ensures basic voltage vectors to be right on the coordinate axes of αβ‐coordinate system, which has the advantages of less computation and higher accuracy than the traditional. It synthesises zero vectors by equalising the duration time of two basic voltage vectors, which are equivalent in amplitude and opposite in phase, to simplify control logic and decrease harmonics of output voltages. To stabilise the DC bus voltage and balance the DC‐side capacitor voltages, a DC‐side voltage control strategy is presented. The former objective is obtained by controlling the active partition of the output currents, and the latter one by adapting the direct partition of phase C output current. An overall control method combining the proposed SVPWM algorithm with the DC‐side voltage control strategy is presented. Experimental results have shown the validity and feasibility of the proposed algorithm and strategy.
Zero‐voltage‐switching DC/DC converter with three three‐level pulse‐width modulation circuit cells
Authors: Lin Bor‐Ren , Chung Shih‐Kai , Shiau Tung‐Yuan
Published: May 2013

This study presents a new soft switching DC/DC converter with current double rectifier to achieve zero‐voltage switching for all power switches under a wide range of load condition. Three three‐level pulse‐width modulation circuit cells sharing the same power switches are adopted in the proposed converter to reduce the voltage stress of each switch at Vin/2 and achieve load current sharing. Therefore the current stress and power rating of the secondary side components are reduced. The current double rectifiers are used at the secondary side to reduce the output ripple current. The sizes of the magnetic components and output filter capacitance can be reduced. The circuit analysis and design consideration of the proposed converter are discussed in detail. The proposed converter can be used in high input voltage and high load current applications. Finally, experiments based on a 1.5 kW scale‐down prototype are provided to verify the effectiveness of the proposed converter.
Non‐linear power oscillation damping controllers for doubly fed induction generators in wind farms
Authors: Elkington Katherine , Ghandhari Mehrdad
Published: May 2013

This study presents two methods for designing power oscillation damping (POD) controllers for wind farms comprising doubly fed induction generators (DFIGs). The first is the residue method, which uses linear feedback. The second method uses a non‐linear signal as feedback. Here linear matrix inequalities (LMIs) and regional pole placement are used to determine the feedback gains for multiple wind farms simultaneously so that the power system satisfies a minimum damping ratio. The impact of the designed POD controllers in wind farms is demonstrated in a test power system. Modal analysis is used to design controllers using both the residue and LMI methods, and dynamic simulations are used to demonstrate the contribution of the wind farms to power system damping. Numerical simulations show that DFIGs, such as those found in wind farms, are capable of damping oscillations, and also illustrate the effectiveness of using non‐linear feedback controllers.
Investigation of a low‐power, double‐sided switched reluctance generator for wave energy conversion
Authors: Pan Jianfei , Zou Yu , Cao Guangzhong
Published: May 2013

In this paper, a low‐power, direct‐drive, double‐sided linear switched reluctance generator (LSRG) is designed and constructed as one of the components of generator matrix for wave power utilizations by direct energy conversion. This machine has the characteristics of simple construction, mechanical robustness, and maintenance free. Following the theoretical background of linear power generation, characteristic investigation is performed by finite element analysis, which shows that each phase can be controlled individually and normal forces can be approximately counteracted from the double‐sided structure. Both preliminary power simulation and experimental results show that there is an optimized generation region for turn‐on and turn‐off position control strategy. The closed loop test based on Pulse Width Modulation (PWM) of current waveforms also demonstrate that for a wide range of wave speed excitations, PWM scheme should be combined with other control strategies for uniform current level regulations.
Doubly‐fed induction generator wind turbine modelling for detailed electromagnetic system studies
Authors: Lei Ting , Barnes Mike , Ozakturk Meliksah
Published: May 2013

Wind turbine (WT) technology is currently driven by offshore development, which requires more reliable, multi‐megawatt turbines. Models with different levels of detail have been continuously explored but tend to focus either on the electrical system or the mechanical system. This study presents a 4.5 MW doubly‐fed induction generator (DFIG) WT model with pitch control. The model is developed in a simulation package, which has two control levels, the WT control and the DFIG control. Both a detailed and a simplified converter model are presented. Mathematical system block diagrams of the closed‐loop control systems are derived and verified against the simulation model. This includes a detailed model of the DC‐link voltage control – a component which is usually only presented in abstract form. Simulation results show that the output responses from the two models have good agreement. The grid‐side converter control with several disturbance inputs has been evaluated for three cases and its dynamic stiffness affected by operating points are presented. In addition, the relation of pitch controller bandwidth and torsional oscillation mode has been investigated using a two‐mass shaft model. This model can be employed to evaluate the control scheme, mechanical and electrical dynamics and the fault ride‐through capability for the turbine.
Design of backstepping power control for grid‐side converter of voltage source converter‐based high‐voltage dc wind power generation system
Authors: Wang Guo‐Dong , Wai Rong‐Jong , Liao Yong
Published: May 2013

This study presents a backstepping power control (BPC) design for the grid‐side voltage source converter (GSVSC) in a voltage source converter‐based high‐voltage dc (VSC‐HVDC) wind power generation system. First, a dynamic model by taking parameter variations and external disturbances into account is derived on the basis of the space‐vector theory to achieve the decoupling control characteristic of the GSVSC in the VSC‐HVDC. Moreover, based on the backstepping design procedure, a BPC scheme is developed in the sense of Lyapunov stability theorem for the GSVSC to satisfy multiple objectives of a stable HVDC bus and the grid connection with a unity power factor. The salient feature of the proposed BPC is the introduction of additional error terms into the control laws to reduce the chattering phenomena in traditional backstepping control. In addition, the effectiveness of the proposed BPC scheme is demonstrated by numerical simulations on a doubly‐fed induction generator wind farm with VSC‐HVDC grid connection, and its advantage is indicated in comparison with a traditional proportional‐integral control strategy under a wide range of operating conditions and the possible occurrence of uncertainties.
A density functional theory of chiral block copolymer melts
Authors: Wang Shih-Hao , Kawakatsu Toshihiro , Chen Peilong , Lu Chun-Yi David
Published: May 2013

A density functional theory is developed for the diblock copolymer melt, where one block contains the segment orientation dependent chiral interaction. In addition to the standard (scalar) pair interaction between the two types of monomers, the chiral block has the additional pairwise interaction, which is linear in the tangent vectors of the segments. We construct a density functional, which contains both the scalar density field and the vector chain alignment field. The quadratic part of the density functional comes from the mean field theory of the microscopic model, whereas the fourth order terms are introduced phenomenologically in the spatially local form. From the stability analysis of this model, we find that the additional chiral interaction shifts the order-disorder transition, which is consistent with the behavior of experimental system. Further numerical calculation reveals a new metastable chiral helical cylinder structure, which is similar to the one found experimentally. Another similar metastable structure but with zigzag modulation is also observed. As the helical and zigzag structures disappear when the chiral interaction is switched off, we understand that the chiral effect is the driving force for the formation of these exotic metastable structures.