bluuebunny/crossref_metadata_2025 huggingface dataset:
The interactive animated e-book as a word learning device for kindergartners
Authors: SMEETS D. J. H. , BUS A. G.
Published: January 2014

Electronic picture storybooks often include motion pictures, sounds, and background music instead of static pictures, and hotspots that label/define words when clicked on. The current study was designed to examine whether these additional elements aid word learning and story comprehension and whether effects accumulate making the animated e-book that also includes hotspots the most promising device. A sample group of 136 4- and 5-year-old kindergarten children were randomly assigned to one of four conditions: static e-books, animated e-books, interactive animated e-books, and a control group. In experimental conditions, four on-screen stories were each presented four times during a 4-week intervention period. Children in the control condition played nonliteracy related computer games during the same time. In all conditions, children worked independently with the computer programs. Strong treatment effects were found on target vocabulary originating from the story. Pupils gained most in vocabulary after reading interactive animated e-books, followed by (noninteractive) animated e-books and then static e-books. E-books including animations and interactivity were neither beneficial nor detrimental for story comprehension. Findings suggest that electronic storybooks are valuable additions in support of the classroom curriculum with interactive animated e-books being the best alternative.
Precise Point Positioning Using the Regional BeiDou Navigation Satellite Constellation
Authors: Xu Aigong , Xu Zongqiu , Xu Xinchao , Zhu Huizhong , Sui Xin , Sun Huasheng
Published: January 2014

On 27 December 2012 it was announced officially that the Chinese Navigation Satellite System BeiDou (BDS) was able to provide operational services over the Asia-Pacific region. The quality of BDS observations was confirmed as comparable with those of GPS, and relative positioning in static and kinematic modes were also demonstrated to be very promising. As Precise Point Positioning (PPP) technology is widely recognized as a method of precise positioning service, especially in real-time, in this contribution we concentrate on the PPP performance using BDS data only. BDS PPP in static, kinematic and simulated real-time kinematic mode is carried out for a regional network with six stations equipped with GPS- and BDS-capable receivers, using precise satellite orbits and clocks estimated from a global BDS tracking network. To validate the derived positions and trajectories, they are compared to the daily PPP solution using GPS data. The assessment confirms that the performance of BDS PPP is very comparable with GPS in terms of both convergence time and accuracy.
Exact bounds for lift-to-drag ratios of profiles in the Helmholtz–Kirchhoff flow
Authors: MAKLAKOV D. V. , KAYUMOV I. R.
Published: January 2014

In this work we investigate limiting values of the lift and drag coefficients of profiles in the Helmholtz–Kirchhoff (infinite cavity) flow. The coefficients are based on the wetted arc length of profile surfaces. The problem is to find global minimum and maximum values of the drag coefficientCDunder a given lift coefficientCL. We reduce the problem to a constrained problem of calculus of variations and solve it analytically. In so doing we do not only determine extremals but also strictly prove that these extremals realize global extrema. The proofs are based on non-trivial application of Jensen's inequality. The solution of the problem allows us to construct the domain of possible variations of coefficientsCLandCDand define maximum and minimum values of the lift-to-drag ratiosCL/CDfor a givenCL.
Inventing and reinventing the modern city: the 2012 city status competition in the United Kingdom
Authors: BECKETT JOHN
Published: January 2014

Three new cities were created in conjunction with Her Majesty the queen's Diamond Jubilee celebrations in 2012: Chelmsford, Perth and St Asaph. They were the winners of a competition which had no clear rules, no transparency and no proper feedback. The modern style is to create new cities in conjunction with a royal event, the winners to be decided by competition. How has this come to be the case? This article looks at the 2012 competition in the light of the ways in which cities have been created in the United Kingdom since the explicit link with Anglican cathedrals was dropped in 1888, and it asks whether it is worth the effort? The author concludes that what was initially conceived as a means of distinguishing between rivals for the status of city has become a competition driven by modern forms of civic boosterism, and a blatant opportunity for political patronage by governments who hide behind royal ‘privilege’. For all the effort expended, the distinction is hardly recognized outside of the town hall.
THE TAYLOR PRINCIPLE AND (IN-) DETERMINACY WITH HIRING FRICTIONS AND SKILL LOSS
Authors: Rannenberg Ansgar
Published: January 2014

We introduce skill decay during unemployment into a New Keynesian model with hiring frictions and real-wage rigidity. Plausible values of quarterly skill decay and real-wage rigidity turn the long-run marginal cost–unemployment relationship positive in a “European” labor market with little hiring but not in a fluid “American” one. If the marginal cost–unemployment relationship is positive, determinacy requires a passive response to inflation in the central bank's interest feedback rule if the rule features only inflation. Targeting steady-state output or unemployment helps to restore determinacy.
Implementation of Treatment Integrity Procedures
Authors: Goense Pauline , Boendermaker Leonieke , van Yperen Tom , Stams Geert-Jan , van Laar Jose
Published: January 2014

This systematic review evaluates the implementation of treatment integrity procedures in outcome studies of youth interventions targeting behavioral problems. The Implementation of Treatment Integrity Procedures Scale (ITIPS), developed by Perepletchikova, Treat, and Kazdin (2007) , was adapted (ITIPS-A) and used to evaluate 32 outcome studies of evidence-based interventions for youths with externalizing behavioral problems. Integrity measures were found to be still rare in these studies. Of the studies that took integrity into account, 80% approached adequacy in implementing procedures for treatment integrity. The ITIPS-A is recommended as an instrument to guide development of integrity instruments and the implementation of treatment integrity procedures in youth care.
Clustering Practitioners Within Service Organizations May Improve Implementation Outcomes for Evidence-Based Programs
Authors: Klest Sihu K.
Published: January 2014

Data for the present study were collected from Parent Management Training Oregon model (PMTO) therapists (n = 83) employed in Norwegian social service organizations. Survey data were analyzed using partial correlation, MANCOVA, and contrast tests. There were statistically significant positive relationships between the number of PMTO therapists working in an agency and respondents reports of: (1) how many families they had treated with PMTO in the past 6 months, (2) PMTO being well integrated in their organization, and (3) how much time they have to practice PMTO in their current position. In addition, practitioners in organizations with more PMTO colleagues were significantly less likely to report that they would stop using the program. Finally, there was a marginally significant positive relationship between the number of PMTO therapists in an agency and practitioners’ reports that they received a sufficient number of PMTO cases. The size of the organization, the number of years therapists had worked with PMTO, and therapist perception of agency leadership were controlled for. Contrast tests suggested that the most prominent differences were between agencies with three PMTO therapists versus agencies with one or two practitioners. There were exceptions to this result; for example, individual practitioners with four or more therapists in their agencies had treated significantly more families with PMTO in the past six months than those with three or fewer therapists. There were large effect sizes for the MANCOVA, F(20, 249) = 10.38, p < .01, η p 2 = .39, as well as the univariate tests. Implementation outcomes were not improved for PMTO therapists if there were practitioners within their agencies working with an evidence-based program other than PMTO. Results suggest that clustering practitioners using the same program within an organization, in groups of three or more, could contribute to successful implementation outcomes for evidence-based programs.
Spiral attractor created by vector solitons
Authors: Sergeyev Sergey V , Mou Chengbo , Turitsyna Elena G , Rozhin Alexey , Turitsyn Sergei K , Blow Keith
Published: January 2014

Mode-locked lasers emitting a train of femtosecond pulses called dissipative solitons are an enabling technology for metrology, high-resolution spectroscopy, fibre optic communications, nano-optics and many other fields of science and applications. Recently, the vector nature of dissipative solitons has been exploited to demonstrate mode locked lasing with both locked and rapidly evolving states of polarisation. Here, for an erbium-doped fibre laser mode locked with carbon nanotubes, we demonstrate the first experimental and theoretical evidence of a new class of slowly evolving vector solitons characterized by a double-scroll chaotic polarisation attractor substantially different from Lorenz, Rössler and Ikeda strange attractors. The underlying physics comprises a long time scale coherent coupling of two polarisation modes. The observed phenomena, apart from the fundamental interest, provide a base for advances in secure communications, trapping and manipulation of atoms and nanoparticles, control of magnetisation in data storage devices and many other areas.
Developmental trajectory of contextual learning and 24-h acetylcholine release in the hippocampus
Authors: Takase Kenkichi , Sakimoto Yuya , Kimura Fukuko , Mitsushima Dai
Published: January 2014

To determine the developmental trajectory of hippocampal function in rats, we examined 24-h changes in extracellular acetylcholine (ACh) levels and contextual learning performance. Extracellular ACh significantly correlated with spontaneous behavior, exhibiting a 24-h rhythm in juvenile (4-week-old), pubertal (6-week-old) and adult (9- to 12-week-old) rats. Although juveniles of both sexes exhibited low ACh levels, adult males had higher ACh levels than adult females. Moreover, juveniles exhibited much more spontaneous activity than adults when they showed equivalent ACh levels. Similarly, juveniles of both sexes exhibited relatively low contextual learning performance. Because contextual learning performance was significantly increased only in males, adult males exhibited better performance than adult females. We also observed a developmental relationship between contextual learning and ACh levels. Scopolamine pretreatment blocked contextual learning and interrupted the correlation. Since long-term scopolamine treatment after weaning impaired contextual learning in juveniles, the cholinergic input may participate in the development of hippocampus.
Ion dynamics in a trapped ion mobility spectrometer
Authors: Hernandez Diana Rosa , DeBord John Daniel , Ridgeway Mark E. , Kaplan Desmond A. , Park Melvin A. , Fernandez-Lima Francisco
Published: January 2014

In the present paper, theoretical simulations and experimental observations are used to describe the ion dynamics in a trapped ion mobility spectrometer.
Recent advances in the fabrication and detection of lectin microarrays and their application in glycobiology analysis
Authors: Li Hong , Wei Liming , Fang Pan , Yang Pengyuan
Published: January 2014

The lectin microarray technology with high-throughput and flexibility of assays might fulfil all the criteria needed for the direct, rapid and multiplexed monitoring of glycan profiling.
Improving the quantitative accuracy of surface-enhanced Raman spectroscopy by the combination of microfluidics with a multiplicative effects model
Authors: Xia Tian-Hong , Chen Zeng-Ping , Chen Yao , Jin Jing-Wen , Yu Ru-Qin
Published: January 2014

Accurate quantitative SERS analysis was achieved through the combination of microfluidics with a multiplicative effects model.
An autonomous T-rich DNA machine based lateral flow biosensor for amplified visual detection of mercury ions
Authors: Liu Jie , Chen Lingbo , Chen Junhua , Ge Chenchen , Fang Zhiyuan , Wang Lin , Xing Xuerong , Zeng Lingwen
Published: January 2014

An autonomous thymine rich DNA machine as an amplification unit was developed for the sensitive detection of mercury ions with high specificity.
Chemical consequences of mechanical bonding in catenanes and rotaxanes: isomerism, modification, catalysis and molecular machines for synthesis
Authors: Neal Edward A. , Goldup Stephen M.
Published: January 2014

We highlight some of the less discussed consequences of mechanical bonding for the chemical behaviour of catenanes and rotaxanes, including striking recent examples where molecular motion controls chemical reactions.
Reductive deoxygenation of CO2 by a bimetallic titanium bis(pentalene) complex
Authors: Kilpatrick Alexander F. R. , Cloke F. Geoffrey N.
Published: January 2014

The bimetallic bis(pentalene) complex Ti2(μ:η5,η5-C8H4{SiiPr3-1,4}2)2 reduces CO2 to afford dicarbonyl and bridging oxo-complexes.
Oxygen evolution reaction electrocatalyzed on a Fenton-treated gold surface
Authors: Esakki Karthik Pitchiah , Jeyabharathi Chinnaiah , Phani Kanala Lakshminarasimha
Published: January 2014

Hydroxyl radicals arising from the Fenton reagent remove metastable surface gold atoms (low coordinated high-energy surface atoms) on the Au surface, thus precluding the formation of stable oxides and electrocatalizing oxygen evolution reaction.
The genetic incorporation of thirteen novel non-canonical amino acids
Authors: Tuley Alfred , Wang Yane-Shih , Fang Xinqiang , Kurra Yadagiri , Rezenom Yohannes H. , Liu Wenshe R.
Published: January 2014

Thirteen novel non-canonical amino acids were synthesized and tested for suppression of an amber codon using a mutant pyrrolysyl-tRNA synthetase–tRNAPylCUA pair.
Redox-triggered changes in the self-assembly of a ferrocene–peptide conjugate
Authors: Adhikari Bimalendu , Kraatz Heinz-Bernhard
Published: January 2014

Redox and ultrasound directed self-assembly of a ferrocene–peptide conjugate was studied, showing redox-controlled reorganization between gel nanofibers and spherical micelles.
In situ monitoring of the Li–O2 electrochemical reaction on nanoporous gold using electrochemical AFM
Authors: Wen Rui , Byon Hye Ryung
Published: January 2014

In situ imaging of the Li–O2 electrochemical reaction on nanoporous gold shows the formation and decomposition of Li2O2 nanoparticles at low overpotentials.
Nanocrystallization in magnetron sputtered Zr–Cu–Al–Ag thin film metallic glasses
Authors: Rajan S. Thanka , Nanda Kumar A. K. , Subramanian B.
Published: January 2014

Zr-based thin film metallic glasses (TFMG) were fabricated from a polycrystalline Zr48Cu36Al8Ag8 (at.%) target by DC magnetron sputtering. A series of characterization techniques were employed to study the structure, composition and thermal stability of the glassy coating. Annealing studies show nanocrystallites of CuZr2 in an amorphous matrix.
Tungsten oxide nanostructures based on laser ablation in water and a hydrothermal route
Authors: Zhang Hongwen , Li Yue , Duan Guotao , Liu Guangqiang , Cai Weiping
Published: January 2014

Well-dispersed and surface-stepped tungsten oxide nanostructures can be obtained via stacking of nanosized rectangular cuboids during hydrothermal treatment of LAL obtained precursors.
Epitaxial growth mechanism of pulsed laser deposited AlN films on Si (111) substrates
Authors: Yang Hui , Wang Wenliang , Liu Zuolian , Yang Weijiang , Li Guoqiang
Published: January 2014

The epitaxial growth mechanism and causes of dislocation formation in AlN films on a Si substrate by pulsed laser deposition (PLD) are comprehensively proposed.
Investigation of the effect of liquid–liquid phase separation (LLPS) on nucleation and different growth stages of vanillin and bulk growth of defect-free single crystals from aqueous solution – a new approach
Authors: Parimaladevi P. , Kavitha C. , Srinivasan K.
Published: January 2014

In the present work, the advent of secondary liquid phase and its impact on various growth stages of vanillin single crystals in pure aqueous solution were investigated.
Interface structure and reactivity of water-oxidation Ru–polyoxometalate catalysts on functionalized graphene electrodes
Authors: Ma Changru , Piccinin Simone , Fabris Stefano
Published: January 2014

We combine classical empirical potentials and density functional theory (DFT) calculations to characterize the catalyst/electrode interface of a promising device for artificial photosynthesis.
Double-stranded dimetallic helicates: assembling–disassembling driven by the CuI/CuII redox change and the principle of homochiral recognition
Authors: Boiocchi Massimo , Fabbrizzi Luigi
Published: January 2014

Upon reduction of a mononuclear complex of CuII with a tetradentate ligand (a racemic mixture of the S,S and R,R enantiomers) two dicopper(i) double stranded helicates form, each one containing strands of the same chirality.
Cooperative roles of biological flow and surface topography in guiding sperm migration revealed by a microfluidic model
Authors: Tung Chih-kuan , Ardon Florencia , Fiore Alyssa G. , Suarez Susan S. , Wu Mingming
Published: January 2014

A microfluidic model reveals that surface topography assists sperm to swim against the flow within a channel.
Digital PCR on an integrated self-priming compartmentalization chip
Authors: Zhu Qiangyuan , Qiu Lin , Yu Bingwen , Xu Yanan , Gao Yibo , Pan Tingting , Tian Qingchang , Song Qi , Jin Wei , Jin Qinhan , Mu Ying
Published: January 2014

A more practical, user-friendly digital PCR microchip based on integrated self-priming compartmentalization and dehydration control is first developed.
The critical residues of helix 5 for in vitro pentamer formation and stability of the papillomavirus capsid protein, L1
Authors: Jin Shi , Pan Dong , Zha Xiao , Yu Xianghui , Wu Yuqing , Liu Yongjiang , Yin Fei , Chen Xiaojiang S.
Published: January 2014

The mono-site mutation of the conserved residues, 464LGR466, in the helix 5 of HPV16 L1 completely disrupted the pentamer formation.
Side-chain fullerene polyesters: a new class of high refractive index polymers
Authors: Yan Honghong , Chen Shuang , Lu Min , Zhu Xiang , Li Yanqing , Wu Dezhen , Tu Yingfeng , Zhu Xiulin
Published: January 2014

We demonstrate here the synthesis of side-chain fullerene polyesters, a class of soluble high refractive index polymers (n> 1.70).
Nucleobase peptide amphiphiles
Authors: Serpell Christopher J. , Barłóg Maciej , Basu Kaustuv , Fakhoury Johans F. , Bazzi Hassan S. , Sleiman Hanadi F.
Published: January 2014

A new class of peptide materials is introduced, integrating orthogonal aspects of peptide, nucleoside, and amphiphile chemistry.
Nearly lattice matched all wurtzite CdSe/ZnTe type II core–shell nanowires with epitaxial interfaces for photovoltaics
Authors: Wang Kai , Rai Satish C. , Marmon Jason , Chen Jiajun , Yao Kun , Wozny Sarah , Cao Baobao , Yan Yanfa , Zhang Yong , Zhou Weilie
Published: January 2014

Nearly lattice matched CdSe/ZnTe type-II core–shell nanowires exhibit wurtzite structures and epitaxial interfaces, promising a number of multifunctional nanodevices.
Titania nanobundle networks as dye-sensitized solar cell photoanodes
Authors: Dong Cunku , Xiang Wanchun , Huang Fuzhi , Fu Dongchuan , Huang Wenchao , Bach Udo , Cheng Yi-Bing , Li Xin , Spiccia Leone
Published: January 2014

A titania-nanobundle-network minimizes electron recombination in DSCs, allows fast diffusion of the [Co(bpy)3]2+/3+couple through the photoanode and results in a 7.7% efficiency.
Gold nanoparticle wires for sensing DNA and DNA/protein interactions
Authors: Shao Liqin , Diao J. J. , Tang Zhipeng , Liu Song , Shen Sophie C. , Liu Jiankang , Rui Xianfeng , Yu Dapeng , Zhao Qing
Published: January 2014

Gold nanoparticle wires are formed from nanoparticles by discontinuous Vertical Evaporation-driven Colloidal Deposition, and are shown to achieve a sensitive detection of DNA molecules and their interactions with proteins.
Functional films from unsaturated poly(macrolactones) by thiol–ene cross-linking and functionalisation
Authors: Ates Zeliha , Heise Andreas
Published: January 2014

The synthesis of cross-linked surface-functional polyester films from natural macrolactones and their subsequent reaction with a fluorescent marker are presented.
Controlling the doping level of double-walled carbon nanotubes by using aromatic hydrocarbon complexes
Authors: Chun Kyoung-Yong
Published: January 2014

The level of potassium doping in double-walled carbon nanotubes has been tailored by the combination of potassium and aromatic hydrocarbons in a polar solvent.
Polypyrrole–para-phenolsulfonic acid/tape artificial muscle as a tool to clarify biomimetic driven reactions and ionic exchanges
Authors: Fuchiwaki Masaki , Otero Toribio F.
Published: January 2014

Driven reactions, complex ionic exchanges and structural changes are clarified by bending bilayer muscles and corroborated by EDX analysis.
Local bias induced ferroelectricity in manganites with competing charge and orbital order states
Authors: Figueiras Fábio G. N. , Bdikin Igor K. , Amaral Vitor B. S. , Kholkin Andrei L.
Published: January 2014

Perovskite-type manganites, such as Pr1−xCaxMnO3, La1−xCaxMnO3 and La1−xSrxMnO3 solid solutions, are set forth as a case study of ferroelectricity formation mechanisms associated with the appearance of site- and bond-centered orbital ordering which breaks structural inversion symmetry.
Collagen XXII binds to collagen-binding integrins via the novel motifs GLQGER and GFKGER
Authors: Zwolanek Daniela , Veit Guido , Eble Johannes A. , Gullberg Donald , Ruggiero Florence , Heino Jyrki , Meier Markus , Stetefeld Jörg , Koch Manuel
Published: January 2014

Collagen XXII, a FACIT (fibril-associated collagen with interrupted triple helices), is expressed at the myotendinous junction and the articular surface of joint cartilage. Cellular receptors like collagen-binding integrins are known to bind collagens with distinct binding motifs following the sequence GXOGER. In the present study, we demonstrate the sequences GLQGER and GFKGER as novel binding motifs between collagen XXII and collagen-binding integrins, especially α2β1 integrin. Solid-phase assays and surface plasmon resonance spectroscopy revealed a direct interaction between α2β1 integrin and the motif GFKGER. In addition, immunohistochemical analysis demonstrated partial co-localization of collagen XXII, α2β1 integrin and α11β1 integrin at the myotendinous junction. Furthermore, computational modelling of the motifs GLQGER and GFKGER showed perfect fitting of the sequences into the binding pocket of collagen-binding integrins. Taken together, we demonstrated that collagen XXII interacts with collagen-binding integrins via the new motifs GLQGER and GFKGER.
How the structure of the large subunit controls function in an oxygen-tolerant [NiFe]-hydrogenase
Authors: Bowman Lisa , Flanagan Lindsey , Fyfe Paul K. , Parkin Alison , Hunter William N. , Sargent Frank
Published: January 2014

Salmonella enterica is an opportunistic pathogen that produces a [NiFe]-hydrogenase under aerobic conditions. In the present study, genetic engineering approaches were used to facilitate isolation of this enzyme, termed Hyd-5. The crystal structure was determined to a resolution of 3.2 Å and the hydro-genase was observed to comprise associated large and small subunits. The structure indicated that His229 from the large subunit was close to the proximal [4Fe–3S] cluster in the small subunit. In addition, His229 was observed to lie close to a buried glutamic acid (Glu73), which is conserved in oxygen-tolerant hydrogenases. His229 and Glu73 of the Hyd-5 large subunit were found to be important in both hydrogen oxidation activity and the oxygen-tolerance mechanism. Substitution of His229 or Glu73 with alanine led to a loss in the ability of Hyd-5 to oxidize hydrogen in air. Furthermore, the H229A variant was found to have lost the overpotential requirement for activity that is always observed with oxygen-tolerant [NiFe]-hydrogenases. It is possible that His229 has a role in stabilizing the super-oxidized form of the proximal cluster in the presence of oxygen, and it is proposed that Glu73could play a supporting role in fine-tuning the chemistry of His229 to enable this function.
New algorithm for joint subchannel and power allocation in multi‐cell OFDMA‐based cognitive radio networks
Authors: Forouzan Nafiseh , Ghorashi Seyed Ali
Published: January 2014

In this study, the authors propose an efficient resource allocation algorithm in downlink of an orthogonal frequency division multiple access (OFDMA)‐based multi‐cell underlay cognitive radio network. A more realistic model in which multiple secondary users and primary users coexist in a multi‐cell environment has been considered. The main challenge of this model is inter‐cell as well as intra‐cell interference. The proposed algorithm tackles the challenges by adaptively subchannel and power allocation in cognitive radio network. Firstly, based on initial power allocation and with taking throughput of secondary users and signal‐to‐interference plus noise ratio constraint of the primary users into account, subchannel allocation is done by Hungarian method. Then, an iterative water‐filling is implemented to enhance the initialised power allocation. Simulation results demonstrate the strength of the authors proposed scheme compared with some other suboptimal algorithms. The proposed scheme provides significant improvement over the traditional fixed subchannel allocation scheme in terms of spectral efficiency. In addition, it has been shown that the proposed water‐filling policy loads more power into secondary user's band compared with an equal power allocation policy in order to achieve higher throughput.
Cooperative multicasting based on superposition and layered coding
Authors: Elgendi Mohamed , Nasr Omar A. , Khairy Mohamed M.
Published: January 2014

Cooperative diversity plays an important role in combating channel fading and increasing reliability of wireless communication links. The main purpose of cooperative diversity is to transmit the same data from multiple sources. Hence, there is no inherent capability in the cooperative diversity schemes to deal with scalable types of data, for example, scalable video coded signals. The authors introduce a two‐phase cooperative multicast scheme based on superposition coding to transmit scalable video signals. The new scheme mixes the superposition with cooperative diversity, and chooses the right parameters in both schemes to enhance the system's multicast capability. This study also derives an exact closed‐form expression of the average multicast group throughput in case of Rayleigh flat fading channel. The closed‐form expression allows system designers to choose the correct cooperation and superposition parameters to satisfy the network operator needs. Simulations show that, in addition to the additional degrees of freedom resulting from using cooperation with superposition, the proposed scheme outperforms the conservative scheme and schemes solely exploiting cooperative relaying or superposition. Simulations show that the new scheme can increase the average network throughput more than four times compared to the conservative scheme.
On permutation of space‐time‐frequency block codings
Authors: Morsali Alireza , Talebi Siamak
Published: January 2014

Multi‐input multi‐output‐orthogonal frequency‐division multiplexing is the foundation of next generation of wireless communication systems and space‐time‐frequency block coding (STFBC) is considered one of the best schemes for implementing these systems. STFBCs have very complex structures and many parameters affect their performance. Studies have shown that permutation parameter plays a very important and sensitive role in the construction of STFBCs so much so that a small variation of this parameter could cause a significant change in the value of the coding advantage (CA) which alters the code's performance. In this study, first the authors explore how the permutation parameter affects STFBCs and demonstrate that existing permutation methods do not guarantee to attain the maximum possible CA. Next, they introduce a new structure for STFBCs permutation, which is the basis for the design of a modified model of one recently published STFBC. Comparison of the simulation results from the original and modified codes confirms the latter improves the performance by up to 3 dB. This is an achievement that is also verified by theoretical analysis.
Generalised twin‐box model for compensation of transmitters radio frequency impairments
Authors: Younes Mayada , Ghannouchi Fadhel M.
Published: January 2014

A novel generalised twin‐box model is proposed for the mutual compensation of modulator imperfections and power amplifier (PA) distortion. It is composed of two cascaded boxes, a dual branch of simplified Volterra filters for the joint characterisation of the mild non‐linear dynamic memory effects of the PA and modulator imperfections. The second box is a look‐up table for characterising the highly non‐linear static distortion exhibited by the PA. Hence, the proposed model has reduced complexity in comparison with the state‐of‐the‐art models, owing to the separate identification of the dynamic and static effects of the PA. The model validation is carried out using a Class AB PA, and the proposed model showed significant improvement in performance as well as reducing the computational complexity of the model.
Low complexity user scheduling algorithm for energy‐efficient multiuser multiple‐input multiple‐output systems
Authors: Sun Chuiqiang , Ge Jianhua , Li Jing , Zhu Bin
Published: January 2014

In downlink multiuser multiple‐input multiple‐output (MU‐MIMO) systems, block diagonalisation (BD) is a well‐known precoding technique that eliminates inter‐user interference. The number of simultaneously supportable users with BD is limited by the number of base station transmit antennas and the number of user receive antennas. Traditional MU‐MIMO scheduling algorithms focus on sum capacity. However, these user scheduling algorithms might not be optimal with respect to energy efficiency. Here, the authors consider the energy‐efficient MU‐MIMO scheduling that maximises the energy efficiency. The brute‐force search for the optimal user set, however, is computationally prohibitive. Therefore they propose a low‐complexity user scheduling algorithm for energy‐efficient MU‐MIMO systems. They first obtain an approximation expression for the energy efficiency by utilising the upper bound of the MU‐MIMO system capacity. Then they show that the maximum energy efficiency can be achieved if the scheduling user set is selected to obtain the largest matrix volume. The numerical results show that the proposed algorithm achieves a good tradeoff between energy efficiency and computational complexity. They also consider the problem of maintaining fairness among users, and propose a simplified proportional fair (PF) scheduling algorithm.
Power allocation for hidden‐pilot‐aided precoding schemes in orthogonal frequency division multiplexing systems
Authors: Kim Byung Wook , Jung Sung‐Yoon
Published: January 2014

The allocation of power to the pilot in hidden‐pilot‐aided precoding schemes, which provide high efficiency in bandwidth utilisation, for orthogonal frequency division multiplexing systems was investigated. By maximising the lower bound on the effective signal‐to‐interference plus noise ratio, the closed‐form solution was derived for pilot power allocation in both the low and high signal‐to‐noise ratio regions. Numerical results present the advantages of the proposed scheme for allocating power to the hidden pilot in terms of bit error rate and average channel capacity.
Recognising human interaction from videos by a discriminative model
Authors: Kong Yu , Liang Wei , Dong Zhen , Jia Yunde
Published: January 2014

This study addresses the problem of recognising human interactions between two people. The main difficulties lie in the partial occlusion of body parts and the motion ambiguity in interactions. The authors observed that the interdependencies existing at both the action level and the body part level can greatly help disambiguate similar individual movements and facilitate human interaction recognition. Accordingly, they proposed a novel discriminative method, which model the action of each person by a large‐scale global feature and local body part features, to capture such interdependencies for recognising interaction of two people. A variant of multi‐class Adaboost method is proposed to automatically discover class‐specific discriminative three‐dimensional body parts. The proposed approach is tested on the authors newly introduced BIT‐interaction dataset and the UT‐interaction dataset. The results show that their proposed model is quite effective in recognising human interactions.
Unified power flow controller impact on power system predictability
Authors: Galvani Sadjad , Tarafdar Hagh Mehrdad , Banna Sharifian Mohamad Bagher
Published: January 2014

Accurate prediction of power system state has significant importance specially in bidding strategies, risk management and operational decisions. Consideration of this matter is very important, especially in systems with large penetration of renewable energies such as wind powers. The effect of the most versatile flexible alternative current transmission systems (FACTS) devices unified power flow controller (UPFC) on predictability of power system state has been studied. For this purpose, predictability indices are used which can quantify the ability of system prediction. The likely harmful properties of UPFC in power system predictability are presented and the results are discussed on IEEE 14 and IEEE 57 bus test system.
Continuation power flow based on a novel local geometric parameterisation approach
Authors: Ju Yuntao , Wu Wenchuan , Zhang Boming , Sun Hongbin
Published: January 2014

Continuation power flow based on global parameterisations cannot overcome the Jacobian matrix singularity for some voltage instability cases with strong local characteristics and local parameterisation methods may need a forced parameter‐switching strategy at the lower part of P–V curve and a special step‐length tuning algorithm. The upper part of P–V curve can be solved through conventional newton power flow easily with load factor as parameterisation variable. Therefore this study focuses on tracing the segment near the saddle‐node bifurcation (SNB) point and the lower part of P–V curve. A new local geometric parameterisation technique is proposed, which can trace P–V curve with a fixed step‐length of parameterisation variable and no parameter‐switching strategy is needed in most cases. The Jacobian matrix singularity near the SNB is avoided by the addition of a linear equation, which is determined from the selected bus voltage magnitude and the loading factor. The method to deal with limit‐induced bifurcation problems is also considered in this study.
Black‐box dynamic equivalent model for microgrids using measurement data
Authors: Papadopoulos Panagiotis N. , Papadopoulos Theofilos A. , Crolla Paul , Roscoe Andrew J. , Papagiannis Grigoris K. , Burt Graeme M.
Published: January 2014

A dynamic equivalent black‐box model, based on Prony analysis is presented. The proposed model is suitable for dynamic studies of microgrids, considering changes in the active and reactive powers, bus voltages, currents and frequency. The developed model is evaluated using simulation results obtained from a medium‐voltage microgrid and test measurements recorded in a low‐voltage microgrid laboratory test facility. Results from the proposed model are in good agreement with the corresponding responses obtained from both simulations and laboratory tests. The examined microgrid configurations include rotating machines and inverter interfaced units implementing different control strategies, thus verifying the robustness of the proposed model.
Linear parameter‐varying control of permanent magnet synchronous generators for wind power systems
Authors: Trilla Lluís , Bianchi Fernando D. , Gomis‐Bellmunt Oriol
Published: January 2014

This study presents an optimal control strategy for the electronic interface of a wind energy conversion system based on a permanent magnet synchronous generator (PMSG). A linear optimal control is used on the grid side of the interface to ensure a proper power transfer and a linear parameter‐varying (LPV) control on the machine side to cope with the wide operating conditions demanded by the wind turbine applications. The dynamics of a PMSG working in a variable speed wind turbine is affected by the rotational speed of the wind rotor. The LPV control uses the generator speed as a scheduling variable to adapt itself to different operating conditions. The proposed scheme results in a multi‐variable self‐scheduled controller with a PI structure similar to classical approaches. Thus, the control ensures performance and stability in all possible operating conditions whereas the implementation and the numerical stability are similar to previous schemes. The proposed control has been implemented in a test bench that includes a fully‐rated back‐to‐back converter. The experimental results show a good performance in different scenarios in which the controller has to adapt itself to highly varying operating conditions.
Predictive modulation schemes to reduce common‐mode voltage in three‐phase inverters‐fed AC drive systems
Authors: Hoseini Seyed Kazem , Adabi Jafar , Sheikholeslami Abdolreza
Published: January 2014

Pulse width modulation controlled inverters produce common‐mode voltage, which has been reported to cause many system drawbacks. This voltage along with high dv/dt raises leakage currents which can result in serious problems such as motor damage and electromagnetic interference to the surrounding equipment. Also common‐mode voltage is responsible for bearing failure and overvoltage stress to the winding insulation of an AC motor. Therefore knowledge of reducing common‐mode voltage is essential to provide a correct insight into the design of the drive system. Previous methods for common‐mode voltage reduction cause extra harmonic in output currents, since they are based on voltage control. This study proposes new modulation strategies based on predictive current control (PCC) for three‐phase pulse width modulation inverters‐fed AC motor drive systems which mitigate the common‐mode voltage and moreover, decrease the harmonic contents of output currents. As PCC can be employed in low voltage and medium voltage drive applications, the proposed strategies have been implemented on two‐level and three‐level neutral‐point clamped inverter. A comparative study of proposed techniques with traditional ones has been carried out from the output current total harmonic distortion point of view. Simulation results and mathematical analyses, along with experimental tests for two‐level inverter using Texas Instrument DSP model TMS320F28335, confirm that the new strategies improve behavior of drive systems in comparison with previous methods.
Deadbeat direct power control of three‐phase pulse‐width modulation rectifiers
Authors: Zhang Yongchang , Xie Wei , Zhang Yingchao
Published: January 2014

Direct power control (DPC) is a powerful control scheme for three‐phase AC/DC converters, because of its decoupled control of active/reactive power and quick dynamic response with simple structure. However, relative high‐power ripples at steady state and variable switching frequency can be observed in conventional DPC. Furthermore, the harmonic spectrum of current is broad and not easy to be filtered. This study tries to improve the steady‐state performance of conventional DPC by using deadbeat power control. Two kinds of deadbeat control methods are proposed and the first one aims to achieve deadbeat control of active power, whereas the second one aims to achieve deadbeat control of both active power and reactive power. Compared with conventional DPC, the two deadbeat power control methods achieve significant steady‐state performance improvement in terms of lower power ripples and less current harmonics, even if the sampling frequency is much lower. Moreover, the quick dynamic response of conventional DPC is maintained in the proposed methods. The two kinds of deadbeat methods are comparatively studied, with the basic DPC as the benchmark. The presented experimental results validate the effectiveness of the proposed deadbeat power control methods.
Design and implementation of dynamic electronic load controller for three‐phase self‐excited induction generator in remote small‐hydro power generation
Authors: Chilipi RajaSekhara Reddy , Singh Bhim , Murthy Shikaripur Srinivasa , Madishetti Sandeep , Bhuvaneswari Gurumoorthy
Published: January 2014

This study presents design and implementation of a dynamic electronic load controller (DELC) for voltage and frequency control of a three‐phase self‐excited induction generator (SEIG) driven by constant power unregulated small‐hydro turbine. This DELC is a combination of insulated‐gate bipolar transistor‐based voltage sourced converter (VSC) and variable frequency drive (VFD) which is connected across the DC link of VSC. The VFD operates in direct torque control mode and is coupled with a pumping system. The DELC is connected at point of common coupling in parallel with consumer loads. The VSC provides instantaneous control of the SEIG voltage through reactive power compensation. The VFD consumes the power in excess of consumer loads to maintain constant generator output power which in turn regulates the frequency. The excess generated power consumed by the VFD is used to pump water either to an overhead tank or for irrigation purposes. The performance of the proposed DELC of SEIG is demonstrated under various types of loads such as linear/non‐linear, balanced/unbalanced loads and so on. Test results recorded on a developed DELC of SEIG exhibit simultaneous voltage and frequency control capabilities of the DELC under varying loads.
Inferring non‐synonymous single‐nucleotide polymorphisms‐disease associations via integration of multiple similarity networks
Authors: Wu Jiaxin , Yang Silu , Jiang Rui
Published: January 2014

Detecting associations between human genetic variants and their phenotypic effects is a significant problem in understanding genetic bases of human‐inherited diseases. The focus is on a typical type of genetic variants called non‐synonymous single nucleotide polymorphisms (nsSNPs), whose occurrence may potentially alter the structures of proteins, affecting functions of proteins, and thereby causing diseases. Most of the existing methods predict associations between nsSNPs and diseases based on features derived from only protein sequence and/or structure information, and give no information about which specific disease an nsSNP is associated with. To cope with these problems, the identification of nsSNPs that are associated with a specific disease from a set of candidate nsSNPs as a binary classification problem has been formulated. A new approach has been adopted for predicting associations between nsSNPs and diseases based on multiple nsSNP similarity networks and disease phenotype similarity networks. With a series of comprehensive validation experiments, it has been demonstrated that the proposed method is effective in both recovering the nsSNP‐disease associations and inferring suspect disease‐associated nsSNPs for both diseases with known genetic bases and diseases of unknown genetic bases.
Estimation of switching characteristics in quantum‐dot cellular automata using probability model
Authors: Xiangye Chen , Li Cai , Kaixiang Jia , Xiaokuo Yao , Mingliang Zhang
Published: January 2014

Quantum‐dot cellular automata (QCA) is a novel computational paradigm which utilises the quantum mechanism to encode and process bit information. The switching characteristics of the QCA majority gate are evaluated by using the proposed probability model. All kinds of probabilities are achieved by solving the time‐independent Schrodinger equation. The simulation results reveal that the majority gate switches at a higher correct probability when the cell distance and the size decrease. Cell miniaturisation would raise a significant implication in how to realise reliable QCA fabrication. In addition, the results also illuminate that majority output has different probabilities when the inputs change. Therefore, to analyse the QCA circuit reliability by using the probability model, all the input combinations must be considered.
Video-Assisted Thoracoscopic Anterior Surgery Combined Posterior Instrumentation for Children with Spinal Tuberculosis
Authors: Zheng Changkun , Li Peng , Kan WuSheng
Published: January 2014

Background The use of thoracoscopy for the treatment of spinal disorders has been applied mostly in adults. However, thoracoscopic decompression of spinal tuberculosis in children has probably been rarely documented.

Objective To assess the efficacy of video-assisted thoracoscopic anterior surgery (VATS) combined with posterior instrumentation for children with spinal tuberculosis.

Study Design Total 15 consecutive children with spinal tuberculosis with VATS combined with posterior instrumentation were included.

Methods Overall 15 cases of spinal tuberculosis were treated with the procedure of posterior internal fixation and anterior debridement by VATS combined with posterior instrumentation between January 2002 and December 2006.There were nine males and six females with an average age of 11.6 years (8–15 y). All patients were given appropriate chemotherapy for 4 to 12 weeks preoperatively and 12 to 15 months postoperatively. All patients were followed up with evaluation of the changes of kyphotic deformity noted.

Results All the cases were followed up over an average of 37.3 months (range, 12–48 mo).The wounds were healed without chronic infection or sinus formation. Four patients improved three grades, two patients improved two grades, and seven patients improved one grade. The average neurological recovery in the patients was 1.44 grades on the scale by Frankel et al. The average preoperative kyphosis was 37 degrees (range, 23–59 degrees) and the average postoperative kyphosis was 25 degrees (range, 18–35 degrees) at final follow-up. Also, minimal progression of kyphosis was seen at final follow-up with an average kyphosis of 28 degrees (range, 20–40 degrees); and average loss of correction of 3 degree was seen at final follow-up.

Conclusions VATS combined with posterior instrumentation achieve satisfactory results for children with spinal tuberculosis.