bluuebunny/crossref_metadata_2025 huggingface dataset:
The Prevalence of Ptosis and Nystagmus in Rural Population
Authors: Hashemi Hassan , Molaei Leila , Yekta Abbasali , Aghamirsalim Mohammadreza , Ostadimoghaddam Hadi , Jabbari-Azad Frida , Khabazkhoob Mehdi
Published: December 2018

Purpose:

To determine the prevalence of ptosis and nystagmus in the general rural population in Iran.

Methods:

Two villages were selected from the north and southwest of Iran using a multi-stage cluster sampling approach. After selection of the participants and inviting them to a complete eye exam, they all had vision tests and an ophthalmic examination. Vision tests included measurement of visual acuity, refraction, and the cover test. Then the slit-lamp exam was performed, and the diagnosis of ptosis and nystagmus was determined by an ophthalmologist.

Results:

Of the 3851 invitees, 3314 people participated in the study. The prevalence of ptosis in this study was 2.23% [95% confidence interval (CI): 1.73-2.74], and 45.3% of the cases were bilateral ptosis. The prevalence of ptosis was lowest in the 21-30 year (0.2%) and the under 5 year (0.8%) age groups, and the highest prevalence was observed in people over 70 years of age (6.7%) (P < 0.001). The prevalence of ptosis was higher in illiterate people than those with an academic education level (P = 0.012). The prevalence of astigmatism was 62.8% in those with ptosis and 34.2% in those without ptosis (P < 0.001). The prevalence of nystagmus was 0.39% (13 cases).

Conclusions:

This study found that the prevalence of ptosis is relatively high in the general rural population in Iran, and the prevalence increases with age. Astigmatism is significantly high among cases with ptosis, and its prevalence has an inverse relation with the level of education. Nystagmus also had a high prevalence in this population.
Community-Driven Science: Update on the Thriving Earth Exchange
Authors: Pandya Raj
Published: December 2018

As AGU marks its Centennial, our organization’s program that recruits volunteer scientists to help with local priorities celebrates 5 years of working in communities representing 12 million people.
The Outer Radiation Belt Response to the Storm Time Development of Seed Electrons and Chorus Wave Activity During CME and CIR Driven Storms
Authors: Bingham S. T. , Mouikis C. G. , Kistler L. M. , Boyd A. J. , Paulson K. , Farrugia C. J. , Huang C. L. , Spence H. E. , Claudepierre S. G. , Kletzing C.
Published: December 2018

Gyroresonant wave‐particle interactions with very low frequency whistler mode chorus waves can accelerate subrelativistic seed electrons (hundreds of keV) to relativistic energies in the outer radiation belt during geomagnetic storms. In this study, we conduct a superposed epoch analysis of the chorus wave activity, the seed electron development, and the outer radiation belt electron response between L* = 2.5 and 5.5, for 25 coronal mass ejection and 35 corotating interaction region storms using Van Allen Probes observations. Electron data from the Magnetic Electron Ion Spectrometer and Relativistic Electron Proton Telescope instruments are used to monitor the storm‐phase development of the seed and relativistic electrons, and magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science instrument are used to identify the chorus wave activity. Our results show a deeper (lower L*), stronger (higher flux), and earlier (epoch time) average seed electron enhancement and a resulting greater average radiation belt electron enhancement in coronal mass ejection storms compared to the corotating interaction region storms despite similar levels and lifetimes of average chorus wave activity for the two storm drivers. The earlier and deeper seed electron enhancement during the coronal mass ejection storms, likely driven by greater convection and substorm activity, provides a higher probability for local acceleration. These results emphasize the importance of the timing and the level of the seed electron enhancements in radiation belt dynamics.
Alfvénic Heating in the Cusp Ionosphere‐Thermosphere
Authors: Lotko William , Zhang Binzheng
Published: December 2018

The effect of electromagnetic variability on cusp‐region ionosphere‐thermosphere heating is examined. The study is motivated by observed correlations between anomalous thermospheric density enhancements at F region altitudes and small‐scale field‐aligned currents, previously interpreted as evidence of ionospheric Alfvén resonator modes. Height‐integrated and height‐dependent heating rates for Alfvén waves incident from the magnetosphere at frequencies from 0.05 to 2 Hz and perpendicular wavelengths from 0.5 to 20 km have been calculated. The velocity well in Alfvén speed surrounding the F region plasma density maximum facilitates energy deposition by slowing, trapping, and intensifying resonant waves. The Alfvénic Joule heating rate maximizes at the resulting resonances. F region Joule heating resulting from quasistatic and Alfvénic variability with the same root‐mean‐square amplitude in the F region are shown to be comparable. At the same time, Alfvénic variability deposits little electromagnetic power in the E region, whereas quasistatic variability greatly enhances E region heating. When measured electric and magnetic fields are used to constrain the amplitude and spectral content of superposed Alfvén waves incident from the magnetosphere, the calculated F region heating rate ranges from 5 to 10 nW/m3.
Simulations of the Generation of Energetic Electrons and the Formation of Descending Artificial Plasma Layers During HF Heating at Arecibo
Authors: Eliasson B. , Milikh G. M. , Liu T. C. , Shao X. , Papadopoulos K.
Published: December 2018

High‐frequency (HF)‐induced descending artificial plasma layers (DAPLs) are artificially ionized plasma layers with plasma density in excess of that of the F2 peak. They were discovered during HF heating experiments at the High‐Frequency Active Auroral Research Program where they descended up to 70 km from the initial O mode wave reflection height. The DAPLs were attributed to the ionization of the neutral gas by high‐energy electrons accelerated by the artificial ionospheric turbulence. Recently, DAPL formation was reported during the HF heating experiment at Arecibo (Bernhardt et al., 2017, https://ies2017.bc.edu/). This result was unexpected since Arecibo has the effective radiated power 4–5 times lower than that at High‐Frequency Active Auroral Research Program, and since the experiment at Arecibo also has an unfavorable geometry, where the HF beam is directed vertically while the inclination of the geomagnetic field is 43.5°, allowing the fast electrons to escape the volume where their interaction with the artificial plasma turbulence occurs. However, the presence of photoelectrons due to the ultraviolet radiation from the Sun at the low latitude of Arecibo could magnify the flux of hot electrons. A model of artificial plasma layers created by the Arecibo HF facility is presented. It shows that Langmuir turbulence due to the HF heating can accelerate part of the ambient photoelectrons to energies above the ionization threshold of the neutral gas, leading to the formation of DAPLs. The present model results are in quantitative agreement with the experiments of Bernhardt et al. (2017).
Permutation Entropy Analysis of Magnetic Field Turbulence at 1AU Revisited
Authors: Olivier C. P. , Engelbrecht N. E. , Strauss R. D.
Published: December 2018

Permutation entropy analysis is a relatively recent addition to the palette of techniques used to study spacecraft observations of heliospheric magnetic field fluctuations at Earth, allowing one to characterize the underlying processes driving the observed fluctuations. This study investigates the effects of data averaging, data gaps, and underlying periodicities on the results of such an analysis, utilizing synthetic data sets and thereby developing efficient treatments for each of these effects. Furthermore, WIND spacecraft observations are employed to validate the results of an earlier permutation entropy analysis by Weck et al. (2015, https://doi.org/10.1103/PhysRevE.91.023101), confirming the results of that study and showing how dat averaging effects can significantly affect the results so acquired. Lastly, as a novel application of this technique, Advanced Composition Explorer spacecraft data taken from 1998 to 2008 are analyzed to investigate whether the permutation entropy so calculated displays a solar cycle dependence. It is shown that although solar cycle dependencies have been reported for observed turbulence quantities such as the magnetic variance, there is no significant dependence discernible in the permutation entropy, and therefore in the underlying processes driving the turbulence.
Observations and Fokker‐Planck Simulations of the L‐Shell, Energy, and Pitch Angle Structure of Earth's Electron Radiation Belts During Quiet Times
Authors: Ripoll J.‐F. , Loridan V. , Denton M. H. , Cunningham G. , Reeves G. , Santolík O. , Fennell J. , Turner D. L. , Drozdov A. Y. , Cervantes Villa J. S. , Shprits Y. Y. , Thaller S. A. , Kurth W. S. , Kletzing C. A. , Henderson M. G. , Ukhorskiy A. Y.
Published: December 2018

The evolution of the radiation belts in L‐shell (L), energy (E), and equatorial pitch angle (α
0) is analyzed during the calm 11‐day interval (4–15 March) following the 1 March 2013 storm. Magnetic Electron and Ion Spectrometer (MagEIS) observations from Van Allen Probes are interpreted alongside 1D and 3D Fokker‐Planck simulations combined with consistent event‐driven scattering modeling from whistler mode hiss waves. Three (L, E, α
0) regions persist through 11 days of hiss wave scattering; the pitch angle‐dependent inner belt core (L ~ <2.2 and E < 700 keV), pitch angle homogeneous outer belt low‐energy core (L > ~5 and E~ < 100 keV), and a distinct pocket of electrons (L ~ [4.5, 5.5] and E ~ [0.7, 2] MeV). The pitch angle homogeneous outer belt is explained by the diffusion coefficients that are roughly constant for α
0 ~ <60°, E > 100 keV, 3.5 < L < L

pp
 ~ 6. Thus, observed unidirectional flux decays can be used to estimate local pitch angle diffusion rates in that region. Top‐hat distributions are computed and observed at L ~ 3–3.5 and E = 100–300 keV.
An Investigation of Ocean Model Uncertainties Through Ensemble Forecast Experiments in the Southwest Atlantic Ocean
Authors: Lima L. N. , Pezzi L. P. , Penny S. G. , Tanajura C. A. S.
Published: December 2018

Ocean general circulation models even with realistic behavior still incorporate large uncertainties from external forcing. This study involves the realization of ensemble experiments using a regional model configured for the Southwest Atlantic Ocean to investigate uncertainties derived from the external forcing such as the atmosphere and bathymetry. The investigation is based on perturbing atmospheric surface fluxes and bathymetry through a series of ensemble experiments. The results showed a strong influence of the South Atlantic Convergence Zone on the underlying ocean, 7 days after initialization. In this ocean region, precipitation and radiation flux perturbations notably impacted the sea surface salinity and sea surface temperature, by producing values of ensemble spread that exceeded 0.08 and 0.2 °C, respectively. Wind perturbations extended the impact on currents at surface, with the spread exceeding 0.1 m/s. The ocean responded faster to the bathymetric perturbations especially in shallow waters, where the dynamics are largely dominated by barotropic processes. Ensemble spread was the largest within the thermocline layer and in ocean frontal regions after a few months, but by this time, the impact on the modeled ocean obtained from either atmospheric or bathymetric perturbations was quite similar, with the internal dynamics dominating over time. In the vertical, the sea surface temperature exhibited high correlation with the subsurface temperature of the shallowest model levels within the mixed layer. Horizontal error correlations exhibited strong flow dependence at specific points on the Brazil and Malvinas Currents. This analysis will be the basis for future experiments using ensemble‐based data assimilation in the Southwest Atlantic Ocean.
Eddy‐Resolving In Situ Ocean Climatologies of Temperature and Salinity in the Northwest Atlantic Ocean
Authors: Seidov Dan , Mishonov Alexey , Reagan James , Parsons Rost
Published: December 2018

Circulation patterns and thermohaline fields of the Northwest Atlantic are highly variable in space and time and are strongly impacted by various mesoscale phenomena such as quasi‐stationary frontal zones with sharp gradients, meandering jet‐like currents, vortexes, and filaments. These all contribute to building and maintaining complex large‐scale regional structures of ocean tracers, such as temperature and salinity, which persist over time periods of decades and longer. To reflect the existence of these long‐term mesoscale phenomena and diagnose their changes, a new high‐resolution in situ climatology of the Northwest Atlantic was developed. At its core, this eddy‐resolving climatology, with 1/10° horizontal resolution, reveals a cumulative effect of mesoscale dynamics within the Northwest Atlantic. Additionally, strong agreement exists between this in situ climatology and climatologies derived from high‐resolution satellite data, thus providing a validation of the presence of stochastic periodicity of ocean tracer patterns on decadal timescales. Furthermore, large and very localized multidecadal subsurface heat gains southeast of the Gulf Stream was diagnosed using this new high‐resolution regional climatology. It was demonstrated that the climatic shifts in the wind stress over the Northwest Atlantic may play a leading role in this heat accumulation due to subtropical water heaving through Ekman pumping. It is argued that uncovering many important details of long‐term ocean climate variability from in situ ocean data can only be ascertained through the use of eddy‐resolving climatologies.
Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana
Authors: Díez Fernández Rubén , Jiménez‐Díaz Alberto , Arenas Ricardo , Pereira M. Francisco , Fernández‐Suárez Javier
Published: December 2018

The Calzadilla Ophiolite is an ensemble of mafic and ultramafic rocks that represents the transition between lower crust and upper mantle of a Cadomian (peri‐Gondwanan) fore arc. Mapping and structural analysis of the ophiolite demonstrates that it was obducted in latest Ediacaran times, because the Ediacaran‐Early Cambrian sedimentary series (Malcocinado Formation) discordantly covers it. The ophiolite and emplacement‐related structures are affected by Variscan deformation (Devonian‐Carboniferous), which includes SW verging overturned folds (D1) and thrusts (D2), upright folds (D3), extensional faults (D4), and later faults (D5). These phases of deformation are explained in the context of Variscan tectonics as the result of the progressive collision between Gondwana and Laurussia. Qualitative unstraining of Variscan deformation reveals the primary geometry of Ediacaran‐Cambrian structures and uncovers the generation of east verging thrusts as responsible for the primary obduction of the Calzadilla Ophiolite. Restoration of planar and linear structures associated with this event indicates an Ediacaran, east directed obduction of the ophiolite, that is, emplacement of the Cadomian fore arc onto inner sections of the northern margin of Gondwana. According to regional data, the obduction separates two extension‐dominated stages in the tectonic evolution of the African margin of northern Gondwana preserved in southern Europe. Preobduction extension brought about the onset and widening of fore‐arc and back‐arc basins in the external part of the continent, while postobduction extension facilitated the formation of extensional migmatitic domes, an oceanward migration of back‐arc spreading centers across peri‐Gondwana, and the eventual opening of a major basin such as the Rheic Ocean.
Pyrrolopyrrole aza-BODIPY near-infrared photosensitizer for dual-mode imaging-guided photothermal cancer therapy
Authors: Wu Chaolong , Huang Xiaoyu , Tang Yunyun , Xiao Wanyue , Sun Liguo , Shao Jinjun , Dong Xiaochen
Published: December 2018

A NIR photosensitizer pyrrolopyrrole aza-BODIPY (PPAB) was synthesized in a straightforward manner.
Efficient hydrogen evolution on (CuInS2)x(ZnS)1−x solid solution-based photocathodes under simulated sunlight
Authors: Zhao Jiao , Minegishi Tsutomu , Kaneko Hiroyuki , Ma Guijun , Zhong Miao , Nakabayashi Mamiko , Hisatomi Takashi , Katayama Masao , Shibata Naoya , Yamada Taro , Domen Kazunari
Published: December 2018

A thin film of (CuInS2)x(ZnS)1−x has been developed as a photocathode for solar water splitting for the first time.
Rhodium(iii) vs. cobalt(iii): a mechanistically distinct three-component C–H bond addition cascade using a Cp*RhIII catalyst
Authors: Li Ruirui , Ju Cheng-Wei , Zhao Dongbing
Published: December 2018

Rhodium(iii) vs. cobalt(iii) in three-component C–H bond additions: the RhIII-catalytic system constitutes a complementary access with the CoIII-catalytic system, which involved a different rate-determining step and catalytic cycle with a different scope of substrates.
Structural reconstruction of germanosilicate frameworks by controlled hydrogen reduction
Authors: Ma Yue , Xu Hao , Liu Xue , Peng Mingming , Mao Wenting , Han Lu , Jiang Jingang , Wu Peng
Published: December 2018

Calcined UTL-type germanosilicate was firstly reduced in a hydrogen atmosphere at an appropriate temperature. Then, air-calcination and water-washing procedures were performed to remove the Ge metal clusters or crystals originated from the reduction of skeleton germanium(iv) to yield pure zeolite phase of two daughter structures analogous to IPC-2 and IPC-6.
Alkali metal salts of 3,6-dinitramino-1,2,4,5-tetrazine: promising nitrogen-rich energetic materials
Authors: Zhang Tianhe , Du Jiang , Li Zhimin , Lin Xinyu , Wang Lin , Yang Li , Zhang Tonglai
Published: December 2018

The alkali metal salts of 3,6-dinitramino-1,2,4,5-tetrazine were synthesized and characterized, which may be excellent “green” energetic materials.
A universal layer-by-layer solution-processing approach for efficient non-fullerene organic solar cells
Authors: Sun Rui , Guo Jing , Sun Chenkai , Wang Tao , Luo Zhenghui , Zhang Zhuohan , Jiao Xuechen , Tang Weihua , Yang Chuluo , Li Yongfang , Min Jie
Published: December 2018

A universal layer-by-layer solution-processing approach is proven to be effective for the fabrication of high-performance non-fullerene organic solar cells.
A novel fluorescence immunosensor based on Förster resonance energy transfer between nitrogen and sulfur co-doped carbon dot functionalized silica nanospheres and Au@Ag NPs
Authors: Cao Jun-Tao , Zhang Wen-Sheng , Wang Hui , Ma Shu-Hui , Liu Yan-Ming
Published: December 2018

A fluorescence immunosensor for PSA detection was developed based on the FRET between Si/NS-CDs and Au@Ag NPs.
Lysosome-targeted two-photon fluorescent probes for rapid detection of H2S in live cells
Authors: Li Gongchun , Ma Saige , Tang Jun , Ye Yong
Published: December 2018

Two novel two-photon fluorescent probes (BHNP-DAandM2) were designed and synthesized and show good selectivity and high sensitivity to H2S.
Glucose oxidase-loaded liposomes forin situamplified signal of electrochemical immunoassay on a handheld pH meter
Authors: Liang Jiaming , Wang Jing , Zhang Luwei , Wang Sijia , Yao Cuiping , Zhang Zhenxi
Published: December 2018

Methods based on a pH meter have been developed for immunoassays, but most involve low sensitivity and weakly detectable signals, and thus are unsuitable for routine use.
Synthesis and characterization of manganese(ii) complexes supported by cyclopentadienyl-phosphine ligands
Authors: Wang Gao-Xiang , Yin Jianhao , Li Jiapeng , Yin Zhu-Bao , Zhang Wen-Xiong , Xi Zhenfeng
Published: December 2018

A series of manganese(ii) complexes supported by cyclopentadienyl-phosphine ligands have been synthesized and characterized. [LMn(μ-Cl)]2 served as a precursor to organomanganese(ii) derivatives.
Insights into the intrinsic capacity of interlayer-expanded MoS2 as a Li-ion intercalation host
Authors: Gong Shan , Zhao Guangyu , Lyu Pengbo , Sun Kening
Published: December 2018

Interlayer-expanded O-MoS2 can accommodate more Li-ions than non-expanded MoS2.
Construction of a dual-channel mode for wide spectrum-driven photocatalytic H2 production
Authors: Zhang Lulu , Zhang Hongwen , Wang Bo , Huang Xueyan , Gao Fan , Zhao Yan , Weng Sunxian , Liu Ping
Published: December 2018

The composite with heavily incorporated HxWO3 (H0.53WO3/CdS) was successfully synthesized by a facile method of photo-assisted in situ reduction and applied in photocatalytic water splitting into H2.
Controllable synthesis of uniform mesoporous H-Nb2O5/rGO nanocomposites for advanced lithium ion hybrid supercapacitors
Authors: Li Shengyuan , Wang Ting , Zhu Wangqin , Lian Jiabiao , Huang Yunpeng , Yu Yang-Yang , Qiu Jingxia , Zhao Yan , Yong Yang-Chun , Li Huaming
Published: December 2018

Uniform mesoporous H-Nb2O5/rGO nanocomposites are developed for advanced lithium ion hybrid supercapacitors with remarkably high energy/power densities and excellent cycling stability.
HxMoO3−ynanobelts: an excellent alternative to carbon electrodes for high performance mesoscopic perovskite solar cells
Authors: Zhang Hua , Wang Huan , Yang Yinglong , Hu Chen , Bai Yang , Zhang Teng , Chen Wei , Yang Shihe
Published: December 2018

The HxMoO3−ynanobelts as electrode has been firstly demonstrated with efficiency up to 14.5% in mesoscopic perovskite solar cells. This work thus opens up a new direction for developing electrode materials for more efficient mesoscopic perovskite solar cells.
A DOPA-functionalized chondroitin sulfate-based adhesive hydrogel as a promising multi-functional bioadhesive
Authors: Zhu Wenzhen , Iqbal Jabed , Wang Dong-An
Published: December 2018

A novel DOPA-functionalized chondroitin sulfate-based (CSD) bioadhesive hydrogel with excellent functionality and biocompatibility for internal medical applications.
Predicted photovoltaic performance of lead-based hybrid perovskites under the influence of a mixed-cation approach: theoretical insights
Authors: Liu Diwen , Li Qiaohong , Hu Jinyu , Jing Huijuan , Wu Kechen
Published: December 2018

Hybrid organic–inorganic halide perovskite solar cells have recently attracted much attention because of their highly efficient photovoltaic performance.
All-inorganic cesium lead halide perovskite nanocrystals: synthesis, surface engineering and applications
Authors: Yang Di , Cao Muhan , Zhong Qixuan , Li Pengli , Zhang Xiaohong , Zhang Qiao
Published: December 2018

The synthetic approaches, morphological control, passivation methods, applications and outlook of CsPbX3 nanocrystals have been summarized in this article.
Strongly luminescent inorganic–organic hybrid semiconductors with tunable white light emissions by doping
Authors: Liu Wei , Banerjee Debasis , Lin Fang , Li Jing
Published: December 2018

Tunable white light emissions from copper bromide based inorganic–organic hybrid semiconductors have been observed upon doping.
A luminescent metal–organic framework integrated hydrogel optical fibre as a photoluminescence sensing platform for fluorescence detection
Authors: Zhao Lishuai , Gan Jiulin , Xia Tifeng , Jiang Licheng , Zhang Jun , Cui Yuanjing , Qian Guodong , Yang Zhongmin
Published: December 2018

A fluorescence detection platform based on a metal–organic framework material incorporated hydrogel optical fiber is proposed for the first time.
Molecular design and synthesis of D–π–A structured porphyrin dyes with various acceptor units for dye-sensitized solar cells
Authors: Zhou Haoran , Ji Jung-Min , Kang Sung Ho , Kim Min Su , Lee Hyun Seok , Kim Chul Hoon , Kim Hwan Kyu
Published: December 2018

The large efficiency loss for the SGT-023-based device with a stronger electron-withdrawing pyridothiadiazole unit could be ascribed to a fast charge recombination rate caused by the tilted adsorption mode on the TiO2 surface.
Spectrum sensing based on Bayesian generalised likelihood ratio for cognitive radio systems with multiple antennas
Authors: Al‐Amidie Muthana , Al‐Asadi Ahmed , Micheas Athanasios C. , Islam Naz E.
Published: December 2018

In this paper, the spectrum sensing problem is addressed via using multiple antennas in cognitive radio systems when the noise and the primary user signal are independent. The problem of optimal detection is considered, and an estimation framework is presented where the primary user signal is a complex zero‐mean Gaussian distribution. This paper discusses the generalized likelihood ratio detector (GLRT) when the sample size is a finite number and derive the corresponding GLRT detector of the spectrum sensing problem in a multiantenna framework by utilizing the statistics of the received signal, the channel information and the prior information of the noise. The scenario involves the assumption that the noise variance is unknown while the channel matrix gain is known for the secondary user (SU). The simulation results show that the proposed Bayesian GLRT detector is optimal even under a limited number of samples and more importantly also clarify that the proposed detector outperforms other the state‐of‐the‐art detectors.
Further study on local analysis of continuous‐time T‐S fuzzy models with bounded disturbances
Authors: Hu Guolin , Liu Xiaodong , Wang Likui , Li Hongxing
Published: December 2018

This study further addresses the problem of computing the bounds of disturbances for continuous‐time Takagi‐Sugeno (T‐S) fuzzy models. First, in order to bound the time derivatives of the membership functions, less conservative results, which overcome some drawbacks of the previous results such as special structure of free variable, redundant restrictive conditions and parameters, are obtained by applying the generalised Lyapunov function and non‐quadratic control law. Second, if the disturbances are bounded by energy, some conditions are derived to get two local regions (a smaller and a bigger) that are contained in a specific compact set , and guarantee that all the trajectories starting from the smaller region will remain in the bigger one. Finally, two examples are given to illustrate the effectiveness of the results.
Stochastic stabilisation of wireless networked control systems with lossy multi‐packet transmission
Authors: Zhao Yun‐Bo , Huang Tao , Kang Yu , Xi Xugang
Published: December 2018

The stochastic stabilisation of networked control systems is investigated with a special focus on the lossy multi‐packet transmission in the wireless communication context. The resulting partially available system states due to multi‐packet transmission are firstly reconstructed at the controller, and the sufficient conditions for stochastic stability are then given for the closed‐loop system, which finally leads to a controller design method with explicit consideration of multi‐packet transmission. The proposed theoretical results are verified by both numerical and TrueTime‐based examples.
LMI relaxations for robust gain‐scheduled control of uncertain linear parameter varying systems
Authors: Sadeghzadeh Arash
Published: December 2018

This study deals with the problem of robust gain‐scheduled dynamic output feedback control for uncertain discrete‐time linear parameter varying systems. The obtained controller guarantees an upper bound on the induced ‐gain performance of the closed‐loop system. The system matrices are assumed to depend polynomially on both the scheduling and uncertain parameters which are supposed to belong to intervals with a priori known bounds. To formulate the design problem in a linear matrix inequality (LMI) setting, a required auxiliary matrix is initially determined using a necessary condition for finding a gain‐scheduled controller by the proposed method. Then, a robust gain‐scheduled controller is designed by LMI conditions combined with a scalar search using the obtained auxiliary matrix. The method is applied to an inverted pendulum on a cart to illustrate the benefits and applicability of the proposed method.
Highly efficient parameter estimation algorithms for Hammerstein non‐linear systems
Authors: Mao Yawen , Ding Feng , Xu Ling , Hayat Tasawar
Published: December 2018

Hammerstein system identification is difficult because there exist the product items of the parameters between the non‐linear block and the linear block. This study presents a novel parameter separation based recursive least squares (PS‐RLS) identification algorithm for resolving this problem. Its basic idea is to use a linear filter to filter the output data and the noise, and then to obtain two new identification submodels in each of which the output is linear in the corresponding parameter vector. Compared with the over‐parametrisation based recursive least squares method, the proposed algorithm can avoid estimating the redundant parameters and has a higher computational efficiency. The simulation results show that the proposed PS‐RLS algorithm can generate highly accurate parameter estimates with less computational effort.
Closed‐loop parameter identification of second‐order non‐linear systems: a distributional approach using delayed reference signals
Authors: Miranda‐Colorado Roger
Published: December 2018

This work presents a closed‐loop parameter identification algorithm for a class of second‐order non‐linear systems affected by constant disturbances, quantisation, and state estimation errors. The proposed scheme permits obtaining a linear parameterisation of the non‐linear system by developing a simplified procedure that allows using the distributional framework approach straightforwardly. The parametrisation stage requires signals with known delays. These delays are introduced to the system through the reference signal. Then, the linear parametrisation is used by a least‐squares (LS) algorithm and a state estimator to generate the estimated values of the system parameters and the constant disturbance. The proposed algorithm is compared to a standard off‐line LS algorithm in numerical simulations. Besides, the effectiveness and robustness of the proposed methodology are verified using a Monte Carlo simulation by considering that the system's output is corrupted by white noise. The results indicate that the proposed parameter identification scheme outperforms the LS algorithm, but without requiring any pre‐processing stage.
Optimal distributed learning for disturbance rejection in networked non‐linear games under unknown dynamics
Authors: Tatari Farzaneh , Vamvoudakis Kyriakos G. , Mazouchi Majid
Published: December 2018

In this study, an online distributed optimal adaptive algorithm is introduced for continuous‐time non‐linear differential graphical games under unknown systems subject to external disturbances. The proposed algorithm learns online the approximate solution to the coupled Hamilton–Jacobi–Isaacs equations. Each of the players in the game uses an actor‐critic network structure and an intelligent identifier to find the unknown parameters of the systems. The authors use recorded past observations concurrently with current data to speed up convergence by exploring the state space. The closed‐loop stability and convergence of the policies to Nash equilibrium are ensured by using Lyapunov stability theory. Finally, a simulation example shows the efficiency of the proposed algorithm.
Exponential synchronisation of complex networks with delays and perturbations via impulsive and adaptive control
Authors: Zhang Wanli , Li Chuandong , Yang Shiju , Yang Xinsong
Published: December 2018

This study considers exponential synchronisation of complex networks (CNs) with time‐varying delays and non‐identical perturbations by using hybrid control schemes. Quantised adaptive control and quantised impulsive control are combined, and 1‐norm‐based analytical techniques are wielded. By using hybrid quantised controller, applying 1‐norm‐based analytical methods, and designing new Lyapunov function, sufficient conditions on exponential synchronisation are derived. These synchronisation criteria can guarantee that the considered CNs synchronise with given goal dynamics. Compared with some existing results, the authors results are more general and practical. Numerical simulations are exploited to validate the theoretical results.
Understanding multiple days’ metro travel demand at aggregate level
Authors: Duan Zhengyu , Lei Zengxiang , Zhang Michael , Li Haifeng , Yang Dongyuan
Published: December 2018

Day‐to‐day variation of travel demand has been rarely studied, due to the limitation of traditional transport data collection methods and the difficulty in high‐dimensional data processing. In this study, singular value decomposition (SVD) is used to study the day‐to‐day regularity of metro travel demand, based on four one‐month datasets from the metro networks of Shanghai and Shenzhen, China. The results show that SVD is a tool to understand the intrinsic structure of daily metro travel demand. It is found that daily metro travel demand can be decomposed into three constituents: periodic part, burst part and other part. The periodic part varies weekly and accounts for a majority of the travel demand of origin–destination matrix. The burst part exhibits short‐lived spikes, which are caused by special events or holidays. Also, other part varies randomly and only contributes a fraction of travel demand. Moreover, the periodic part corresponding to the two largest singular values is very stable in 2 months, and accounts for most of the travel demand. Finally, the burst part is used to analyse the impact of a collision accident. This work is helpful for short‐term travel demand prediction, metro operation schedule and emergency management.
Real‐time energy management for commute HEVs using modified A‐ECMS with traffic information recognition
Authors: Li Yang , Jiao Xiaohong
Published: December 2018

To further improve fuel consumption performance of hybrid electric vehicles (HEVs) running on commute route in the face of time‐varying traffic information, this paper investigates a real‐time energy management strategy based on the adaptive equivalent consumption minimization strategy (A‐ECMS) framework with traffic information recognition. The proposed management strategy integrates the global near optimization and the real‐time performance. The simple traffic recognition is constructed by utilising k‐means clustering algorithm to deal with the historical traffic data to form four clusters. The adaptive equivalence factor of the A‐ECMS is designed as a three‐dimensional mapping on each cluster and the system states by employing stochastic dynamic programming (SDP) policy iteration to solve offline the stochastic optimal control problem formulated by each cluster statistical characteristic. In real‐time energy management controller online, the instantaneous power split is performed by the ECMS with a proper equivalent factor, which is obtained from mappings according to the cluster recognised by the current traffic situation and the state‐of‐charge (SOC). The effectiveness of the designed control strategy is verified by the simulation test conducted on GT‐suite HEV simulator over real driving cycles.
Dynamic WPT system for EV charging with integrated energy storage
Authors: Ruddell Steven , Madawala Udaya K. , Thrimawithana Duleepa J.
Published: December 2018

Wireless power transfer (WPT) can be used to charge electric vehicles (EVs) safely and efficiently. Dynamic wireless EV charging systems to charge EVs while moving has been developed but this technology is not yet widespread. One of the key challenges of dynamic charging is the pulsed nature of the transferred power, which may negatively impact battery life and the utility grid. Hybrid energy storage systems have been demonstrated as a potential solution, at the expense of a dedicated converter to interface with the energy storage element. This study presents a possible solution to the problem of adsorption and conditioning of high‐power pulses, in the form of a novel converter topology that combines inductive WPT and super capacitor energy storage without the need for an additional converter stage. A suitable switching pattern is presented along with a steady‐state mathematical model based on inductive power transfer, providing insight into the operation of the system. Experimental results of a prototype bi‐directional WPT system are shown to validate the model and demonstrate the applicability of the proposed converter topology.
Optimal sizing of energy storage considering the spatial‐temporal correlation of wind power forecast errors
Authors: Wang Chengfu , Teng Qijun , Liu Xiaoyi , Zhang Feng , He Suoying , Liang Zhengtang , Dong Xiaoming
Published: December 2018

Energy storage is considered as an effective approach to deal with the power deviation that caused by the stochastic wind power forecast error. Because of the spatial‐temporal correlation of forecast errors for wind farms, which locate close to each other and integrate into the same regional power grid, energy storage could be deployed effectively and economically. Therefore, this study proposes an optimisation method to size the capacity of energy storage system (ESS) considering the spatial‐temporal correlation of forecast errors for multiple nearby wind farms. The copula theory based correlation model of high‐dimensional forecast errors is built to capture the spatial‐temporal characteristics of forecast error. Then, according to multiple scenarios technique, an optimal ESS sizing model is established to minimise the investment and operation costs of the ESS. Meanwhile, an operation strategy considering the trend of prediction and correlation of errors is used to implement rolling operation strategy of ESS. The case studies demonstrate the effectiveness of the new method and illustrate the significant impact of the correlation of forecast error on the capacity of ESS.
Peak and valley regulation of distribution network with electric vehicles
Authors: Li Fucun , Guo Hongxia , Jing Zhen , Wang Zhaojun , Wang Xinku
Published: December 2018

With the increasing number of electric vehicles (EVs), how to make full use of EVs to a peak shaving and valley filling effect on the electrical load, realise the effective interaction between EVs and power grid has become a hot spot of research. However, EV charging is random and uncertain on the characteristics of time and space, in this study, the authors consider the interaction between the EV and the power grid as the foraging behaviour of birds combined with the construction of EV charging station, and build a charge–discharge model based on a particle swarm optimisation algorithm to achieve optimal results through group cooperation. Finally, the feasibility of the scheme is verified by a numerical example.
Direct power control of dual‐active‐bridge dc–dc converters based on unified phase shift control
Authors: An Feng , Song Wensheng , Yang Kexin
Published: December 2018

Dual‐active‐bridge (DAB) dc–dc converters are the important part of the transformerless electric traction drive system in railway application. Also the dynamic characteristic of DAB converters in the electric traction drive system is very significant under the input voltage fluctuation. In order to improve the efficiency and enhance the input voltage step response, a direct power control with current‐stress‐optimised (DPC‐CSO) method based on unified phase‐shift control for DAB converters is proposed in this study. Compared with traditional current‐stress‐optimised scheme, DPC‐CSO scheme can reduce current stress of switching devices and improve efficiency further. Meanwhile, it can keep the output voltage constant when it faces with the input voltage step‐change. In addition, only two voltage sensors are used in DPC‐CSO scheme to reduce system cost. Finally, a scale‐down DAB converter experimental platform is developed, and the experimental results have verified the excellent performance of the proposed DPC‐CSO scheme and correctness of theoretical analysis.
Research on DC component decay time constant of 1000 kV AC filter circuit breakers in UHV converter station
Authors: Zhenqiang Li , Mian Fan , Ying He , Zhipeng Zha
Published: December 2018

In hierarchically connected UHV DC projects, the 1000 kV AC filter sub‐bank in converter station is provided with two 500 kV circuit breakers. To determine the test DC component decay time constant when breakers break short‐circuit current, relevant DC project was modelled in electromagnetic transient program (EMTP) for calculations. It is pointed out that for UHV AC filter circuit breakers, the decay time constant of DC component of short‐circuit current should be determined solely based on the single‐phase to earth fault current. Calculations and analyses were made of the AC and DC components and the DC component decay time constant of filter single‐phase to earth fault current, and the time constant calculated was converted to the test value of breakers with rated short‐circuit breaking current of 63 kA. According to the research results, a time constant of 75 or 90 ms is recommended for the two 500 kV circuit breakers, and it is lower than 120 ms as required by the relevant standards, providing technical support for future breaker tests.
Reliability evaluation and thermal design of medium‐voltage converter for underwater long‐distance high‐voltage direct current transmission system
Authors: Ma Siyuan , Zhao Jinbo , Luo Cheng , Chen Qiong , Zha Ming , Xiong Qiaopo , Luo Zhiqing , Liu Qing , Cheng Lei , He Jie , Wang Heng
Published: December 2018

Underwater long‐distance high‐voltage direct current transmission system can provide long‐term, reliable, and sustainable energy for ocean observatories system which has higher reliability requirement than onshore or conventional underwater equipment. As the main network point for high‐voltage direct current transmission system, medium‐voltage converter of the primary node is at the top layer of power supply chain and its reliability will directly affect the reliability of high‐voltage direct current transmission system. Based on a 2.5 kW medium‐voltage converter, this study proposes a method to evaluate the reliability of medium‐voltage converter with accuracy using the lifetime model of switch by analysis of component junction temperature providing theoretical foundation and technical guidance for medium‐voltage converter design. Owing to the high power density of medium‐voltage converter, the heat dissipation space is restricted to pressure vessel. This study proposes a thermal design method to ensure normal operation condition within appropriate temperature for medium‐voltage converter and verified using ANSYS finite element analysis software.
Aerodynamic drag reduction in a vehicle based on efficient global optimisation
Authors: Yan Chengping , Lai Chenguang , Wang Qingyu , Hu Bo , Deng Liangsheng
Published: December 2018

Vehicle aerodynamic shape optimisation is a typical non‐linear and computationally expensive black box problem, which is severely limited by time and cost of the objective function evaluations during the global optimisation process. To solve the shortcomings of low efficiency and high cost of the existing vehicle drag reduction method, an improved efficient global optimisation (EGO) algorithm is used to optimise a four‐dimensional aerodynamic drag reduction design of a vehicle combined with computational fluid dynamics numerical simulation technology. Moreover, data mining technologies are used to reveal the influence mechanisms of design variables on aerodynamic drag and to analyse the relationship between the variables. It is demonstrated that the improved EGO algorithm, based on the kriging response surface and expected improvement function, can achieve the global optimum with minimum function evaluations. The aerodynamic drag of the optimal design is 1.56% lower than that of the original vehicle. The data mining results showed that the engine hood inclination and the tail upturn angle play a leading role in the vehicle's aerodynamic drag, and the hood inclination has the greatest impact.
Research on modelling of piezoelectric micro‐positioning stage based on PI hysteresis model
Authors: Shan Li , Xiaojing Yang , Yao Li , Ning Liu
Published: December 2018

Piezopositioning stage is widely used in the field of precision positioning. However, the positioning accuracy of the stage is primarily affected by the hysteresis property and dynamic property. In order to obtain high positioning precision, a mathematical model of the micro‐displacement stage needs to be accurately modelled. They take a comprehensive consideration of the hysteresis property and dynamic property of stage and then build a mathematical model by combining these two properties, which can reflect both of the two properties. PI model is adopted to model the hysteresis property, the threshold r is determined by the non‐uniform threshold method, and weight coefficient w is firstly identified by fitting the initial curve under the condition of off‐line, and then on‐line modified when the stage works. Dynamic modelling adopts a second‐order system whose parameters of transfer function model are determined by the frequency analysis method. Comparing with the experiment results and the simulation, the maximum error and the mean error of this model are, respectively, 0.124 and 0.061 µm when the positioning range is 10 V. It indicates that this mathematical model of piezopositioning stage can meet the needs of the precision positioning of the micro‐displacement stage.
Mixing characteristic ofboth subsonic and supersonic unsteady circular jets
Authors: Zhang Huanhao , Chen Zhihua , Sun Xun , Huang Zhengui
Published: December 2018

With the use of large eddy simulation (LES), the initial structure and mixing characteristics of both the subsonic and supersonic circular jets are studied, respectively. The stretched‐vortex model combined with the high‐order hybrid scheme is employed to solve the LES equations. The typical structures of the initial jet at different conditions have been presented and discussed. The formation and evolution process of the vortex ring has been displayed in detail, and the unique characteristics of a compressible vortex ring generated by the unsteady jet have been identified. Furthermore, the engulfment and mixture of ambient gas with the jet gases have been discussed, the different mixing processes of both subsonic and supersonic jets, especially the shock wave effect in a supersonic jet on mixing process, have been illustrated.
Profiling proliferative cells and their progeny in damaged murine hearts
Authors: Kretzschmar Kai , Post Yorick , Bannier-Hélaouët Marie , Mattiotti Andrea , Drost Jarno , Basak Onur , Li Vivian S. W. , van den Born Maaike , Gunst Quinn D. , Versteeg Danielle , Kooijman Lieneke , van der Elst Stefan , van Es Johan H. , van Rooij Eva , van den Hoff Maurice J. B. , Clevers Hans
Published: December 2018

The significance of cardiac stem cell (CSC) populations for cardiac regeneration remains disputed. Here, we apply the most direct definition of stem cell function (the ability to replace lost tissue through cell division) to interrogate the existence of CSCs. By single-cell mRNA sequencing and genetic lineage tracing using two Ki67 knockin mouse models, we map all proliferating cells and their progeny in homoeostatic and regenerating murine hearts. Cycling cardiomyocytes were only robustly observed in the early postnatal growth phase, while cycling cells in homoeostatic and damaged adult myocardium represented various noncardiomyocyte cell types. Proliferative postdamage fibroblasts expressing follistatin-like protein 1 (FSTL1) closely resemble neonatal cardiac fibroblasts and form the fibrotic scar. Genetic deletion of
Fstl1
in cardiac fibroblasts results in postdamage cardiac rupture. We find no evidence for the existence of a quiescent CSC population, for transdifferentiation of other cell types toward cardiomyocytes, or for proliferation of significant numbers of cardiomyocytes in response to cardiac injury.