bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracking Control of Electrically Driven Robots Using a Model-free Observer
Authors: Izadbakhsh Alireza , Khorashadizadeh Saeed , Kheirkhahan Payam
Published: December 2018

This paper presents a robust tracking controller for electrically driven robots, without the need for velocity measurements of joint variables. Many observers require the system dynamics or nominal models, while a model-free observer is presented in this paper. The novelty of this paper is presenting a new observer–controller structure based on function approximation techniques and Stone–Weierstrass theorem using differential equations. In fact, it is assumed that the lumped uncertainty can be modeled by linear differential equations. Then, using Stone–Weierstrass theorem, it is verified that these differential equations are universal approximators. The advantage of proposed approach in comparison with previous related works is simplicity and reducing the dimensions of regressor matrices without the need for any information of the systems’ dynamic. Simulation results on a 6-degrees of freedom robot manipulator driven by geared permanent magnet DC motors indicate the satisfactory performance of the proposed method in overcoming uncertainties and reducing the tracking error. To evaluate the performance of proposed controller in practical implementations, experimental results on an SCARA manipulator are presented.
An examination of food parenting practices: structure, control and autonomy promotion
Authors: Musher-Eizenman Dara R , Goodman Lynnel , Roberts Lindsey , Marx Jenna , Taylor Maija , Hoffmann Debra
Published: December 2018

Objective

In recent years, researchers have been working towards creating a standard conceptual framework of food parenting. To understand how parents’ reports correspond with the proposed model, the current study examined parents’ reports of their feeding behaviours in the context of a newly established framework of food parenting.

Design

Cross-sectional, with a two-week follow-up for a subset of the sample. Participants completed a quantitative and qualitative survey to assess food parenting. The survey included items from common food parenting instruments to measure the constructs posited in the framework. Exploratory factor analyses were conducted to ascertain which items related most closely to one another and factors were mapped on to existing constructs.

Setting

Online.

Participants

Parents of children aged 2·5–7 years (n496). Of these, 122 completed a two-week follow-up.

Results

Analyses revealed eleven aspects of Structure (monitoring; distraction; family presence; meal/snack schedule; unstructured practices; healthy/unhealthy food availability; food preparation; healthy/unhealthy modelling; rules), ten aspects of Coercive Control (pressure to eat; using food to control emotions; food incentives to eat; food incentives to behave; non-food incentives to eat; restriction for health/weight; covert restriction; clean plate; harsh coercion) and seven aspects of Autonomy Promotion (praise; encouragement; nutrition education; child involvement; negotiation; responsive feeding; repeated offering). Content validity, assessed via parents’ open-ended explanations of their responses, was high, and test–retest reliability was moderate to high. Structure and Autonomy Promoting food parenting were highly positively correlated.

Conclusions

In general, parents’ responses provided support for the model, but suggested some amendments and refinements.
The interface between consumers and their food environment in Myanmar: an exploratory mixed-methods study
Authors: Downs Shauna M , Glass Sara , Linn Kay Khine , Fanzo Jessica
Published: December 2018

Objective

To examine consumers’ perceptions of their food environments, their food consumption patterns and preferences, and to better understand the attributes of foods that are available within food environments in Myanmar.

Design

An exploratory mixed-methods study using a combination of focus group discussions, market and consumer surveys.

Setting

Four study settings in Myanmar were included: an upper-income township of Yangon; a lower-income township of Yangon; a middle-income township in the southern Myanmar town of Dawei; and a lower-income village in the country’s dry zone of Magway.

Participants

Thirty-two women participated in the focus groups discussions, twenty market surveys were conducted and 362 consumers (both men and women) completed food consumption surveys.

Results

Focus group participants indicated that the availability of a diverse range of foods had increased over time, while the quality of foods had decreased. Health was seen primarily through the lens of food safety and there was an overall lack of knowledge about which foods were more or less healthy. Consumers preferred fruits, vegetables and red meat compared with highly processed snack foods/beverages. Although consumers reported low intakes of highly processed snack foods, Burmese street food was consumed in high quantities. The market surveys suggested that fresh, minimally processed and highly processed foods were available at all markets across the study settings.

Conclusions

Consumers are exposed to a variety of foods, of varying quality, within their food environments in Myanmar. Interventions aimed at increasing consumer knowledge regarding healthy diets and improving food safety are needed.
ENGINEERED STRUGGLE AND “EARNED” SUCCESS
Authors: Cox Amanda Barrett
Published: December 2018

This paper examines how a nonprofit organization prepares low-income Black and Latino/a students to attend elite boarding high schools. Using ethnographic data, I investigate how the program engineers the experience of academic and emotional struggle for students, how students experience these struggles, and what students learn from this process. I find that the program’s academically-induced emotional rollercoaster serves to strengthen students’ confidence in their academic skills and their ability to persist in the face of academic challenges—a valuable emotional asset for the students as they enter elite boarding schools. However, I argue, the feeling students emerge with of having earned their successes (and failures) may ultimately serve to reproduce the individualistic, meritocratic discourses that support the patterns of social inequality the program helps its students sidestep.
The same or different psychiatrists for in- and out-patient treatment? A multi-country natural experiment
Authors: Giacco D. , Bird V.J. , Ahmad T. , Bauer M. , Lasalvia A. , Lorant V. , Miglietta E. , Moskalewicz J. , Nicaise P. , Pfennig A. , Welbel M. , Priebe S.
Published: December 2018

Aims

A core question in the debate about how to organise mental healthcare is whether in- and out-patient treatment should be provided by the same (personal continuity) or different psychiatrists (specialisation). The controversial debate drives costly organisational changes in several European countries, which have gone in opposing directions. The existing evidence is based on small and low-quality studies which tend to favour whatever the new experimental organisation is.

We compared 1-year clinical outcomes of personal continuity and specialisation in routine care in a large scale study across five European countries.

Methods

This is a 1-year prospective natural experiment conducted in Belgium, England, Germany, Italy and Poland. In all these countries, both personal continuity and specialisation exist in routine care. Eligible patients were admitted for psychiatric in-patient treatment (18 years of age), and clinically diagnosed with a psychotic, mood or anxiety/somatisation disorder.

Outcomes were assessed 1 year after the index admission. The primary outcome was re-hospitalisation and analysed for the full sample and subgroups defined by country, and different socio-demographic and clinical criteria. Secondary outcomes were total number of inpatient days, involuntary re-admissions, adverse events and patients’ social situation. Outcomes were compared through mixed regression models in intention-to-treat analyses. The study is registered (ISRCTN40256812).

Results

We consecutively recruited 7302 patients; 6369 (87.2%) were followed-up. No statistically significant differences were found in re-hospitalisation, neither overall (adjusted percentages: 38.9% in personal continuity, 37.1% in specialisation; odds ratio = 1.08; confidence interval 0.94–1.25; p = 0.28) nor for any of the considered subgroups. There were no significant differences in any of the secondary outcomes.

Conclusions

Whether the same or different psychiatrists provide in- and out-patient treatment appears to have no substantial impact on patient outcomes over a 1-year period. Initiatives to improve long-term outcomes of psychiatric patients may focus on aspects other than the organisation of personal continuity v. specialisation.
Evidence for the Scarr–Rowe Effect on Genetic Expressivity in a Large U.S. Sample
Authors: Woodley of Menie Michael A. , Pallesen Jonatan , Sarraf Matthew A.
Published: December 2018

Using the continuous parameter estimation model (CPEM), a large genotyped adult sample of the population of Wisconsin, USA (the Wisconsin Longitudinal Study) is examined for evidence of the Scarr–Rowe effect, a gene × environment (G×E) interaction that reduces the heritability of IQ among those with low socioeconomic status (SES). This method allows the differential expressivity of polygenic scores predictive of both educational attainment and IQ (EA3) on the phenotype of IQ to be directly operationalized throughout the full range of these variables. Utilizing a parental SES factor-weighted composite as a measure of childhood SES, evidence for the Scarr–Rowe effect was found, that is, the genetic expressivity of EA3 on IQ increased with increasing parental SES (β = 0.08, p = 4.71×10−10, df = 6,255). The effect was found for both the male and female samples separately, β(males) = 0.08, p = 5.27×10−5, df = 3,018; β(females) = 0.08, p = 1.93×10−6, df = 3,236. The effects were furthermore robust to removing outlying values of parental SES and to log-transforming the SES variable. The results are similar to those produced using a more conventional two-way interaction model, with IQ predicting the EA3 × log of parental SES interaction after the main effects; however, CPEM allows for greater model degrees of freedom, thus is better powered to detect the effect when it is small in magnitude (CPEM β = 0.05, p = 6.69×10−5 vs. two-way interaction β = 0.02, pone-tailed = .045, in both models log parental SES is used).
Lunar Science for Landed Missions Workshop Findings Report
Authors: Jawin Erica R. , Valencia Sarah N. , Watkins Ryan N. , Crowell James M. , Neal Clive R. , Schmidt Gregory
Published: December 2018

The Lunar Science for Landed Missions workshop was convened at the National Aeronautics and Space Administration Ames Research Center on 10–12 January, 2018. Interest in the workshop was broad, with 110 people participating in person and 70 people joining online. In addition, the workshop website (https://lunar‐landing.arc.nasa.gov) includes video recordings of many of the presentations. This workshop defined a set of targets that near‐term landed missions could visit for scientific exploration. The scope of such missions was aimed primarily, but not exclusively, at commercial exploration companies with interests in pursuing ventures on the surface of the Moon. Contributed and invited talks were presented that detailed many high priority landing site options across the surface of the Moon that would meet scientific goals in a wide variety of areas, including impact cratering processes and dating, volatiles, volcanism, magnetism, geophysics, and astrophysics. Representatives from the Japan Aerospace Exploration Agency and the European Space Agency also presented about international plans for lunar exploration and science. This report summarizes the set of landing sites and/or investigations that were presented at the workshop that would address high priority science and exploration questions. In addition to landing site discussions, technology developments were also specified that were considered as enhancing to the types of investigations presented. It is evident that the Moon is rich in scientific exploration targets that will inform us on the origin and evolution of the Earth‐Moon system and the history of the inner Solar System, and also has enormous potential for enabling human exploration and for the development of a vibrant lunar commercial sector.
Synthetic mammalian pattern formation driven by differential diffusivity of Nodal and Lefty
Authors: Sekine Ryoji , Shibata Tatsuo , Ebisuya Miki
Published: December 2018

A synthetic mammalian reaction-diffusion pattern has yet to be created, and Nodal-Lefty signaling has been proposed to meet conditions for pattern formation: Nodal is a short-range activator whereas Lefty is a long-range inhibitor. However, this pattern forming possibility has never been directly tested, and the underlying mechanisms of differential diffusivity of Nodal and Lefty remain unclear. Here, through a combination of synthetic and theoretical approaches, we show that a reconstituted Nodal-Lefty network in mammalian cells spontaneously gives rise to a pattern. Surprisingly, extracellular Nodal is confined underneath the cells, resulting in a narrow distribution compared with Lefty. The short-range distribution requires the finger 1 domain of Nodal, and transplantation of the finger 1 domain into Lefty shortens the distribution of Lefty, successfully preventing pattern formation. These results indicate that the differences in localization and domain structures between Nodal and Lefty, combined with the activator-inhibitor topology, are sufficient for reaction-diffusion patterning.
Effective fetch and relative exposure index maps for the Laurentian Great Lakes
Authors: Mason Lacey A. , Riseng Catherine M. , Layman Andrew J. , Jensen Robert
Published: December 2018

Wind exposure is a key physical driver of coastal systems in aquatic environments influencing circulation and wave dynamics. A measure of wind exposure is fetch, the distance over which wind can travel across open water. In large lake systems, such as the Laurentian Great Lakes, estimating fetch has proven to be difficult due to their vast size and complex topobathymetry. Here we describe the development of two spatially discrete indicators of exposure to provide a more accurate indicator of the influence of wind exposure in the nearshore of the Laurentian Great Lakes. We summarized wind data from offshore buoys and used existing tools to calculate effective fetch and a relative exposure index (effective fetch scaled by mean wind speed) at a 30-m grid cell resolution. We validated these models by comparing our exposure maps to the U.S. Army Corps of Engineers Wave Information Studies models and found general agreement. These exposure maps are available for public download for the years 2004–2014.
Magnetic solid-phase extraction based on Ni–Al layered double hydroxide/magnetite nano-hybrid for speciation of Mn(vii)/Mn(ii) in water samples by FAAS
Authors: Abdolmohammad-Zadeh Hossein , Ayazi Zahra , Nezami Kobra
Published: December 2018

Application of Ni–Al layered double hydroxide/magnetite nano-hybrid for speciation of Mn(vii)/Mn(ii) in water samples by flame atomic absorbtion spectrometry is shown.
A Z-scheme Bi2MoO6/CdSe-diethylenetriamine heterojunction for enhancing photocatalytic hydrogen production activity under visible light
Authors: Mei Feifei , Zhang Jinfeng , Dai Kai , Zhu Guangping , Liang Changhao
Published: December 2018

A novel Bi2MoO6/CdSe-diethylenetriamine system shows high visible light photocatalytic H2 evolution activity and excellent photostability.
Fluorescence excitation emission matrices for rapid detection of polycyclic aromatic hydrocarbons and pesticides in surface waters
Authors: Yang Ye Z. , Peleato Nicolás M. , Legge Raymond L. , Andrews Robert C.
Published: December 2018

Rapid water quality assessment was evaluated using an automated fluorescence analysis system.
Synthesis, biological evaluation, and structure activity relationship (SAR) study of pyrrolidine amide derivatives as N-acylethanolamine acid amidase (NAAA) inhibitors
Authors: Zhou Pan , Xiang Lei , Zhao Dongsheng , Ren Jie , Qiu Yan , Li Yuhang
Published: December 2018

N-Acylethanolamine acid amidase (NAAA) is one of the key enzymes involved in the degradation of fatty acid ethanolamides (FAEs), especially for palmitoylethanolamide (PEA).
4D visualisation of in situ nano-compression of Li-ion cathode materials to mimic early stage calendering
Authors: Daemi S. R. , Lu X. , Sykes D. , Behnsen J. , Tan C. , Palacios-Padros A. , Cookson J. , Petrucco E. , Withers P. J. , Brett D. J. L. , Shearing P. R.
Published: December 2018

X-ray nano-tomography was used to study the strain evolution of an NMC electrode under uniaxial compression to mimic calendering.
Incorporation of rubidium cations into blue perovskite quantum dot light-emitting diodes via FABr-modified multi-cation hot-injection method
Authors: Meng Fanyuan , Liu Xinyan , Cai Xinyi , Gong Zifeng , Li Binbin , Xie Wentao , Li Mengke , Chen Dongcheng , Yip Hin-Lap , Su Shi-Jian
Published: December 2018

Rubidium cations (Rb+) can be used to develop blue perovskite quantum dots with simultaneous high photoluminescence and electroluminescence efficiency.
Synthesis and characterization of a single-layer conjugated metal–organic structure featuring a non-trivial topological gap
Authors: Gao Zi'Ang , Hsu Chia-Hsiu , Liu Jing , Chuang Feng-Chuan , Zhang Ran , Xia Bowen , Xu Hu , Huang Li , Jin Qiao , Liu Pei Nian , Lin Nian
Published: December 2018

A single layer of a two-dimensional conjugated network (Ni3(HITP)2) assembled on a Au(111) surface exhibits a non-trivial topological gap.
A mechanically robust silver nanowire–polydimethylsiloxane electrode based on facile transfer printing techniques for wearable displays
Authors: Liang Fang-Cheng , Chang You-Wei , Kuo Chi-Ching , Cho Chia-Jung , Jiang Dai-Hua , Jhuang Fu-Cheng , Rwei Syang-Peng , Borsali Redouane
Published: December 2018

The innovative transfer printing fabrication procedure is facile and inexpensive, and thus applied in various wearable displays.
Site-selectivity control in hetero-Diels–Alder reactions of methylidene derivatives of lawsone through modification of the reactive carbonyl group: an experimental and theoretical study
Authors: Tsanakopoulou Maria , Tsovaltzi Erifili , Tzani Marina A. , Selevos Periklis , Malamidou-Xenikaki Elizabeth , Bakalbassis Evangelos G. , Domingo Luis R.
Published: December 2018

Selective monoacetalization of lawsone inverts the site-selectivity of the Diels–Alder reactions of its alkylidene derivatives favoring the protected β-lapachone derivatives.
From a MMP2/CK2 multitarget approach to the identification of potent and selective MMP13 inhibitors
Authors: Pastor Miryam , Zapico José María , Coderch Claire , Maslyk Maciej , Panchuk Rostyslav , de Pascual-Teresa Beatriz , Ramos Ana
Published: December 2018

In this article, we describe new MMP13 inhibitors, active at low nanomolar concentrations, and with a novel TBB-derived scaffold.
Tailorable degradation of pH-responsive all polyether micelles via copolymerisation with varying acetal groups
Authors: Song Jaeeun , Hwang Eunbyul , Lee Yungyeong , Palanikumar L. , Choi Soo-Hyung , Ryu Ja-Hyoung , Kim Byeong-Su
Published: December 2018

A facile approach with random copolymers composed of two epoxide monomers bearing different acetal groups realizes the tunable kinetics of micelle degradation.
Retracted Article: Synthesis of Fe3+-incorporated open-framework gallium borate catalyst for photocatalytic CO2 reduction driven by visible light irradiation
Authors: Li Qiaoqi , Zhang Lili , Zhao Pu Su , Yin Jingzhou , Xia Jun , Sheng Zhen-Huan , Wang Fei , Wang Zhigang , Yin Chengzhu , Lin Jianhua
Published: December 2018

Gallium borates semiconductors have been developed as effective photocatalysts for water splitting driven by UV light irradiation, but there is no relevant study for the CO2 photoreduction application. Herein, we...
Enhanced optomechanical properties of mechanochemiluminescent poly(methyl acrylate) composites with granulated fluorescent conjugated microporous polymer fillers
Authors: Yuan Yuan , Chen Weiben , Ma Zhe , Deng Yakui , Chen Ying , Chen Yulan , Hu Wenping
Published: December 2018

With the combination of mechanochemiluminescence from 1,2-dioxetane coupled polymers and conjugated microporous polymer nanosheets, a new kind of filling-type mechanolumninescent polymer composite was developed.
Fabrication of poly(β-cyclodextrin)-conjugated magnetic graphene oxide by surface-initiated RAFT polymerization for synergetic adsorption of heavy metal ions and organic pollutants
Authors: Wang Jingjing , Zhang Wenhui , Wei Jun
Published: December 2018

Synergetic adsorption of Cd2+ and SMT was realized on poly(β-cyclodextrin)-conjugated magnetic graphene oxide, which was fabricated by surface-initiated RAFT polymerization.
Changes induced by transition metal oxides in Pt nanoparticles unveil the effects of electronic properties on oxygen reduction activity
Authors: Ometto Felipe B. , Carbonio Emilia A. , Teixeira-Neto Érico , Villullas Hebe M.
Published: December 2018

Relevance of electronic effects in oxygen reduction on Pt nanoparticles is unveiled taking advantage of metal–support interactions.
Physical vapour deposition of cyanine salts and their first application in organic electronic devices
Authors: Gesevičius Donatas , Neels Antonia , Duchêne Léo , Hack Erwin , Heier Jakob , Nüesch Frank
Published: December 2018

A volatile high molecular weight organic salt semiconductor is presented, allowing the introduction of physical vapour deposition techniques in cyanine dye salt semiconductors.
High dielectric constant and energy density achieved in sandwich-structured SrTiO3 nanocomposite thick films by interface modulation
Authors: Xiao Shengqiang , Gao Wenbin , Yao Manwen , Su Zhen , Yao Xi
Published: December 2018

The design of a sandwich structure is conducive to enhancing the dielectric constant and energy density of SrTiO3 nanocomposite thick films.
Programmed twisting of phenylene–ethynylene linkages from aromatic stacking interactions
Authors: Mullin William J. , Pawle Robert H. , Sharber Seth A. , Müller Peter , Thomas Samuel W.
Published: December 2018

Intramolecular aromatic stacking of ortho-pentafluorobenzyl benzoate esters enables the rational design of conformations of conjugated materials by programming twisted phenylene–ethynylene linkages reliably.
High performance MoO3−x/Si heterojunction photodetectors with nanoporous pyramid Si arrays for visible light communication application
Authors: Liu Yujin , Cen Guobiao , Wang Gai , Huang Junwei , Zhou Suhang , Zheng Jingbo , Fu Yong , Zhao Chuanxi , Mai Wenjie
Published: December 2018

Self-powered, fast-response heterojunction photodetectors based on nanoporous pyramid Si arrays are successfully developed. The photodetector is further integrated into a visible light communication system as an optical signal receiver.
Effects of dietary leucine and phenylalanine on gastrointestinal development and small intestinal enzyme activities in milk-fed holstein dairy calves
Authors: Cao Yangchun , Liu Shimin , Yang Xinjian , Guo Long , Cai Chuanjiang , Yao Junhu
Published: December 2018

This study was investigated the effects of dietary supplementation of leucine and phenylalanine on the development of the gastrointestinal tract and the intestinal digestive enzyme activity in male Holstein dairy calves. Twenty calves with a body weight of 38 ± 3 kg at 1 day of age were randomly divided into four groups: a control group, a leucine group (1.435 g·l−1), a phenylalanine group (0.725 g·l−1), and a mixed amino acid group (1.435 g·l−1 leucine plus 0.725 g·l−1 phenylalanine). The supplementation of leucine decreased the short-circuit current (Isc) of the rumen and duodenum (P<0.01); phenylalanine did not show any influence on the Isc of rumen and duodenum (P>0.05), and also counteracted the Isc reduction caused by leucine. Leucine increased the trypsin activity at the 20% relative site of the small intestine (P<0.05). There was no difference in the activity of α-amylase and of lactase in the small intestinal chyme among four treatments (P>0.05). The trypsin activity in the anterior segment of the small intestine was higher than other segments, whereas the α-amylase activity in the posterior segment of the small intestine was higher than other segments. Leucine can reduce Isc of the rumen and duodenum, improve the development of the gastrointestinal tract, and enhance trypsin activity; phenylalanine could inhibit the effect of leucine in promoting intestinal development.
Spectral analysis for diagnosis of bearing defects in induction machine drives
Authors: Jafarian Mohammad Javad , Nazarzadeh Jalal
Published: December 2018

In this study, the finite element method (FEM) is utilised for precise analysis and detection of the bearing faults in induction machine drives. For this purpose, the machine inductances in the presence of slots, teeth, and various bearing failures are obtained by FEM. In addition, the spectrum of the stator currents are analysed by employing the electrical model of the induction machine drives. Some experimental and numerical results are illustrated that the proposed model can consider small bearing failures in high‐noise environments and thus can be used for analysing and detecting bearing failures in induction machine drives.
Unipolar sinusoidal excited switched reluctance motor control based on voltage space vector
Authors: Kuai Songyan , Zhang He , Xia Xinxiang , Li Kui
Published: December 2018

In order to improve the operation performance and decrease the torque ripple of switched reluctance motor (SRM), a new current control method for SRM based on voltage space vector was proposed. In which the stator windings are excited by sinusoidal current with a DC offset to realise the unipolar current excitation. In this control system, zero vectors were used to control zero‐sequence current alone and non‐zero voltage space vector was selected to control d–q‐axis current considering coupling. The reluctance torque component was offset by injecting third harmonic current into the DC bias current, and copper loss was minimised by selecting appropriate current ratio. Experiences verified that the new method can effectively control SRM current. The torque ripple can be reduced with third times harmonic current injection, but the efficiency is also decreased. Compared with the traditional control method, the proposed method is simple, easy to implement, and can effectively suppress torque ripple.
Passive SAR satellite (PASSAT) system: airborne demonstrator and first results
Authors: Atkinson George , Sayin Alp , Stove Andrew , Underwood Craig I. , Cherniakov Mikhail , Antoniou Michael
Published: December 2018

This study presents the development and execution of an airborne experimental campaign as a part of the continuing investigation of a passive synthetic aperture radar using digital television broadcasting stations as illuminators of opportunity, and micro‐/nano‐satellite receivers in low earth orbit. For the flight experiments, a hardware demonstrator was developed that utilised two receiving antennas, allowing both cross‐correlation and auto‐correlation range compression schemes, and was mounted to an airborne platform to image stationary rural areas up to 50 km from the transmitter. This study presents the first image results of these experiments as well as initial analysis of image formation aspects, including range compression scheme and effects on the image quality of the signal to noise on the reference channel.
Low‐complexity robust adaptive beamforming method for MIMO radar based on covariance matrix estimation and steering vector mismatch correction
Authors: Huang Junsheng , Su Hongtao , Yang Yang
Published: December 2018

In this study, the authors consider a low‐complexity robust adaptive beamforming problem in a collocated multiple‐input multiple‐output (MIMO) radar. This study is motivated by the fact that in practical applications, the conventional adaptive beamforming algorithm for MIMO radar requires a large computational complexity and suffers from a great performance degradation because of the finite number of training snapshots, the desired signal steering vector mismatch and the corruption of training data by the desired signal. Since the dimension of the virtual steering vector of the MIMO radar is relatively large, the proposed method can estimate the covariance matrix by using a low‐complexity method to effectively improve the computational efficiency of the adaptive beamforming algorithm and the robustness of the beamformer against the covariance matrix uncertainty. Besides, based on the estimated covariance matrix, the proposed method can also correct the desired signal steering vector mismatch to efficiently prevent the desired signal cancellation phenomenon. Simulation results demonstrate that the performance of the proposed method is always close to that of the optimal processing in a wide range of signal‐to‐noise ratio or of the number of training snapshots.
Optimal design and stress analysis of the transmission line inspection robot along the ground line
Authors: Haitao Wang , Biwu Yan , Ziheng Pu , Yuyao Xiong , Qiang Fan , Jian Li , Lei Zheng
Published: December 2018

Most of the previous literatures of the transmission line inspection robot along the ground wire tend to focus on the obstacle‐surmounting method and motion characteristics. There is less research on the mechanics calculation of the corresponding ground wire. Most of the existing robots are designed with the wheel‐claw mechanism. There is less research on other types of robots. A caterpillar track robot along the ground line is designed in this study. The optimisation design of the obstacle‐surmounting method is carried out. The typical 500 kV transmission line model is established. The stress of the ground wire in the process of robot moving along the ground wire is calculated and analysed under different control climate conditions with the help of the finite element method. The results show that the stress of the ground line has a certain safety margins. However, it may exceed the safety range under harsh climate conditions when the transmission line has heavy gradient. The inspection robot operations need reasonable planning according to the calculation results and the transmission line conditions.
Power system stabiliser PSS4B‐W parameters optimisation and RTDS test verification
Authors: Guo Siyuan , Zhang Shoushou , Zhu Weijun , Li Li , Li Hui
Published: December 2018

This study introduces the mathematical model of a new type of power system stabiliser PSS4B‐W. The concept of crossbreed in genetic algorithm is introduced to particle swarm optimisation algorithm and applied to PSS4B‐W parameter optimisation. With a PCS‐9410 excitation regulator, the semi‐physical simulation system is constituted on a real time digital simulator (RTDS) platform. By measuring the excitation system phase frequency characteristic without compensation, the PSS4B‐W parameter optimisation is converted to a set of parameters optimisation process with inequality constraint. In the RTDS platform, the time‐domain dynamic response of without PSS, adding PSS2B and PSS4B‐W, is compared and analysed. Simulation results show that the optimised PSS4B‐W can provide effective damping in different frequency bands, and have good inverse‐regulation suppression effect.
Impacts of different defects on electrical field distribution in cable joint
Authors: Yang Haisheng , Liu Ling , Sun Kai , Li Jinxian
Published: December 2018

Defects in cable joints, induced in the process of manufacturing or assembling, can alter the distribution of the electrical field seriously. To investigate the impacts of different defects on electrical field distribution in cable joints, equivalent models of 110 kV cable joints with needle damage, impurity defect and scratch in insulation are established, respectively. The distribution of electrical potential and field strength in cable joints with dissimilar defects is obtained by finite element analysis (FEA). The results indicate that the needle damage, among the three different defects, generates most excessive electrical field strength distortion surrounding the defect, even exceeding the breakdown strength of air. The results show that these defects can easily result in partial discharge (PD), which leads them to pay more attention to the operation of cable joints.
Simulation and analysis of EMP transient electromagnetic effect of aircraft
Authors: Chen Chen , Wei Yan , Yang Zhao , Enrong Wang , Chunxiao Fu , Runqing Ma , Jiaming Zhu
Published: December 2018

Recently, significant progress has been made in the design and manufacture of various aircraft, such as military and civilian transporters, helicopters, UAVs etc. Thus, research of lightning protection of aircraft becomes critical. Lightning strikes are unavoidable, but measures can be taken to reduce the negative effects. The understanding of the distribution of the electromagnetic environment inside the aircraft is beneficial to the rational layout of the electronic equipment and cables in the cabin. Based on the CST simulation platform, an aircraft model is used as a small system‐level simulation carrier to simulate the situation when the aircraft is under the EMP radiation. Analysis includes the transient voltage and current induced on various cables. A reasonable cable layout scheme is proposed based on the analysis of the internal electromagnetic environment of the body, thereby improving the flight reliability of the aircraft.
Fault location for MMC–MTDC transmission lines based on least squares‐support vector regression
Authors: Zhang Mingguang , Wang Heng
Published: December 2018

The dc transmission line protection plays a crucial role in the secure operation of a multi‐terminal modular‐multilevel‐converter‐based high‐voltage direct current (MMC–MTDC) system, which is increasingly adopted as a promising option in the power transmission fields. However, the MTDC is the most vulnerable to a dc fault, which paralyses all of the MMCs until the dc fault is cleared out. It is a huge challenge that how to locate and isolate dc fault current and ensure the continuous operation of the healthy part of the MMC–MTDC system under dc faults. This study proposes a least‐squares‐based ɛ‐support vector regression scheme, which captures fault features via the Hilbert–Huang transform. Fault features are used as the inputs of ɛ ‐support vector regression to obtain fault distance. Then, least‐squares method is utilised to optimise the parameters of the model so that it can meet the demand on fault location for MMC–MTDC transmission lines. In the end, the simulation model of the multi‐terminal MMC–HVDC system using PSCAD/EMTDC is built to demonstrate that the proposed method has well reliability and accuracy for fault location.
Experimental research on arc characteristics for a 40.5‐kV vacuum circuit breaker
Authors: Zhan Xiaohan , Liu Xiaoming , Li Longnv , Zhu Gaojia , Li Peiyuan
Published: December 2018

With the proposal and development of the energy internet, the wind power generation techniques, the photovoltaic power generation and the fuel cell, the power generation technology has been further developed and applied on a large scale. The vacuum switch, as one of the core components of the power system, is researched and manufactured to control and protect the grid system. Due to the changes of the external parameters during the development of the vacuum switch arc, it shows different combustion modes and movement modes. The modes have important influences on the success and failure of the vacuum switch. Therefore, studying the dynamic characteristics of the arc shape has important theoretical significance and useful value for improving the working performance and reliability of the vacuum switch. In this paper, the characteristics of the vacuum switch arc and particle motion parameters are studied. By studying and diagnosing the arc characteristics of the vacuum switch, the arc characteristics of a vacuum circuit breaker can be grasped from mechanism analyses and experiments.
Coordination control of positive and negative sequence voltages of cascaded H‐bridge STATCOM operating under imbalanced grid voltage
Authors: Hao Liang , Hanliang Song , Liancheng Xiu , Anling Liu , Bin Zhang
Published: December 2018

When the grid voltage is imbalance, the current decoupling control strategy in d‐q frame designed for the balanced system still let STATCOM output balanced voltage. In this case, the negative sequence component in the grid voltage may cause the device overcurrent. Here, the positive and negative sequence of grid voltage are separated first and that of the STATCOM output voltage is also controlled independently. However, how to determine and coordinate the positive and negative sequence voltage have not been effectively investigated yet. From the perspective of power balance, this paper gets the quantitative relationship between the phase shift angles of the positive and the negative sequence voltages. It also gets the quantitative relationship between the modulation ratios of the positive and the negative sequence voltages, and hence the effective coordination control strategy of positive and negative voltages of cascaded STATCOM operating under imbalanced grid voltage was developed. In addition, the phase of the positive and negative voltages, which is critical for the proposed coordination control strategy, can be obtained by the advanced open‐loop phase synchronisation scheme. Finally, its detailed implementation was also provided. Simulation results show that the proposed method is correct and effective.
Novel MPPT method based on large variance GA‐RBF
Authors: Jing Zhang , Ning Liu , Jiabin Xu , Shengfang Zhao , Yan Xu
Published: December 2018

The photoelectric conversion efficiency of photovoltaic cells is mainly affected by temperature and irradiance. In order to promote the development of photovoltaic power generation, it is necessary to improve the photoelectric conversion efficiency of photovoltaic cells. This paper combines two major factors that affect photovoltaic cells, a maximum power point tracking scheme based on large variation GA‐RBF network is proposed. The system used in this scheme is simulated through Matlab. The simulation results show that the new maximum power point tracking scheme has higher accuracy and rapidity, the photoelectric conversion efficiency of the photovoltaic cell is greatly improved.
Optimal design of the mechanical switch suitable for the ATS
Authors: Wu Jian , Xu Jindong , Lv Dong
Published: December 2018

The automatic transfer switch (ATS) is a medium‐voltage switchgear, which can improve the reliability and quality of the power supply. The mechanical switch is an important part of the ATS based on the LC resonance, and its breaking time directly affects the overall switching time of the ATS. In order to reduce the breaking time and improve the breaking performance, the optimal design of the mechanical switch is made. Firstly, the working principle of the ATS based on the LC resonance is introduced, the general technical scheme of the magnetically controlled mechanical switch is given, and then, two aspects of increasing the voltage of the driving power supply and the size of the discharge capacitance are considered to reduce the breaking time. Experimental results show that the breaking time of the magnetically controlled mechanical switch is significantly reduced from 15 down to 6.39 ms or so by optimising the design, and the breaking performance is effectively improved, which is conducive to the design of the ATS based on the LC resonance.
Deep learning‐based fault location of DC distribution networks
Authors: Guomin Luo , Yingjie Tan , Changyuan Yao , Yinglin Liu , Jinghan He
Published: December 2018

Compared with AC distribution networks, DC ones have a number of advantages. Intensive connections of distributed renewable energy can lead to large amount of power electronic converters and complex models. Underground cable is widely used in DC distribution networks. Accurate location of faults can help engineers find the fault points and shorten the time of maintenance. In DC distribution networks, where only a few measuring units are equipped and low sampling rates are adopted, there is limited data used for fault location. Also, for monopole grounding fault, the fault features are sometimes unobvious for recognition. Deep learning which provides feature hierarchy can learn experiences automatically and recognise raw data as human brain does. It reveals a high potential to solve location problems in DC distribution systems. This paper proposes a depth learning based fault location for DC distribution networks. First, a DC distribution network with radiant topology is modelled, and faults are added with different parameters to simulate various scenarios in practical projects. Then, a deep neural network is generated and trained with normalised fault currents. The parameters of network are discussed according to particular application. Finally, the location performance of deep neural network is tested.
Analysis and design of carbon fibre clamping apparatus for replacement of insulator strings in ultra‐high voltage transmission line
Authors: Zhang Bing , Dai Ruzhang , Ma Wanxun , Wu Huijian , Jiang Lan , Yan Cheng , Zhang Yujiao
Published: December 2018

Aiming at the characteristics of closed fixtures such as large size, heavy weight and difficulty in high‐altitude operation, this study proposed a design method to improve the clamping apparatus for replacement of insulator strings in the ultra‐high‐voltage (UHV) transmission line. After modelling through the finite element method, the mechanical properties of the clamping apparatus are analysed to determine the structure with the fixtures of carbon fibre composites. The proposed clamping apparatus will have the characteristics as high strength, high modulus and low weight, so that if applied in the UHV transmission line, the working efficiency will be improved and the labour intensity will be reduced.
Active and reactive power coordination control strategy of overvoltage for distributed PV integrated grid
Authors: Tuo Song , Jiandong Duan , Ma Xiang
Published: December 2018

Aiming at the voltage rise due to the photovoltaic generation system (PVGS) at the point of common coupling (PCC), the cause is analysed with power transmission theory. Here, the principle and strategies of voltage regulation based on active and reactive power in PVGS are proposed. In this control strategy, the voltage of PCC is tracked by PV system in real time. When the voltage of PCC is normal, inverter will output in the way of maximum power point tracking (MPPT).When the voltage of PCC exceeds the upper limit, the inverter will regulate the voltage using the remaining capacity preferentially. If the remaining capacity is insufficient, the inverter will adjust active output and dynamically calculate the active and reactive best out values. In this way, the voltage of PCC is adjusted in an appropriate range to achieve the active output minimisation and reactive output optimisation of inverter. The experimental results validate the effectiveness of the proposed control scheme for voltage regulation.
Fatigue crack fault diagnosis and prognosis based on hidden semi‐Markov model
Authors: Fan Lei , Wang Shaoping , Duan Haibin , Ran Hongliang
Published: December 2018

Aiming at the fault diagnosis and remaining useful life (RUL) prediction of fatigue cracks of a helicopter main gearbox planet carrier, this article proposes a hidden semi‐Markov model (HSMM) methodology, which introduces the explicit state durational distribution parameters into the traditional hidden Markov model (HMM), thus overcoming the limitation of exponential distribution in HMM, retaining strong pattern recognition and classification ability, and improving the diagnostic and prognostic accuracy, and the effectiveness of the method was verified through experiments.
Effects of persistence time and Au catalyst on the morphology and optical properties of ZnO micro/nanostructures
Authors: Negintaji Zohreh , Mortezaali Abdollah , Torabi Jahromi Amin , Yousefi Elham
Published: December 2018

Zinc oxide (ZnO) micro and nanostructures were synthesised on a quartz substrate by the carbothermal evaporation method. The thin layers of gold were used as a catalyst and syntheses were carried out at different persistence time. Characterisation of the layer was conducted in order to study the effect of persistence time on morphology and crystal structure and optical properties of the fabricated ZnO nanostructures. The samples were characterised by scanning electron microscopy, X‐ray diffraction (XRD) and UV–vis spectrophotometry which were performed to investigate the optical properties of the fabricated ZnO layer. The XRD spectrum clearly shows that the structure is in a hexagonal wurtzite phase. Optical properties of ZnO micro and nanostructures were evaluated from transmittance data using the method proposed by Swanepoel (in the regions λ = 200–900 nm). The study’s results indicate that increasing the persistence time as well as decreasing the size of ZnO nanostructures enhances the optical bandgap to about 3.‏46 eV. To the best of this work's knowledge, this is the first report on the study of the correlation of optical properties obtained by Swanepoel method and morphology of ZnO nanostructures.
Maximum entropy searching
Authors: Jiang Rui , Zhou Hui , Wang Han , Ge Shuzhi Sam
Published: December 2018

This study presents a new perspective for autonomous mobile robots path searching by proposing a biasing direction towards causal entropy maximisation during random tree generation. Maximum entropy‐biased rapidly‐exploring random tree (ME‐RRT) is proposed where the searching direction is computed from random path sampling and path integral approximation, and the direction is incorporated into the existing rapidly‐exploring random tree (RRT) planner. Properties of ME‐RRT including degenerating conditions and additional time complexity are also discussed. The performance of the proposed approach is studied, and the results are compared with conventional RRT/RRT* and goal‐biased approach in 2D/3D scenarios. Simulations show that trees are generated efficiently with fewer iteration numbers, and the success rate within limited iterations has been greatly improved in complex environments.
Dredging-induced shell damages to hard clam (Meretrix meretrix): a Malaysian case study
Authors: Kar Soon Tan , Ransangan Julian
Published: December 2018

The hard clam (Meretrix meretrix) is a popular edible shellfish in South and Southeast Asia, being heavily exploited by hand dredging in Marudu Bay, Malaysia. The current study was performed to evaluate the shell damages caused by this artisanal dredging gear. Samplings were conducted in triplicates at two sites using both hand dredging and hand collecting (control) sampling methods. The shell length and total weight, damage areas and breakage patterns of each clam were recorded. A questionnaire survey was conducted with local bivalve harvesters to gather information on the fishing pressure in Marudu Bay. Results revealed that the efficiency (fishing yield) of hand dredging gear was three times higher than hand collecting. However, hand dredging gear causes lethal shell damages to small hard clams (<3cm in shell length). Hard clam harvesting is the main occupation of most fishermen in Kg. Popok, but most of them do not comply with the minimum harvesting size established by the fishery department. Moreover, most of the stakeholders are not aware of the negative impacts of hand dredging to the sustainability of the hard clam fishery in Marudu Bay. Therefore, organizing more awareness programs combined with introducing community-based fishery management are highly recommended to promote the sustainability of this artisanal fishery.