bluuebunny/crossref_metadata_2025 huggingface dataset:
A new three-factor authentication scheme overcome repeat registered attack for wireless sensor networks
Authors: Li Ye , Zhang Min
Published: March 2020

In the wireless sensor networks (WSNs), users sometimes need to access real-time information from a certain sensor node. In order to prevent unauthorized users from acquiring information from the sensor node, a lot of authentication schemes suited for the WSNs condition have been proposed. Recently, Das has proposed a secure and light-weight authentication scheme for the WSNs based on three factors, claiming that it can withstand various attacks. But after a careful analysis, there are still several security problems as follows: a) The scheme has some design flaws; b)The scheme may suffer sensor node impersonation attack; c) The scheme may suffer repeat registered attack; d) When the user access the sensor node, the scheme cannot protect the identity information of the sensor node. To solve these problems, a new scheme using the secure sketch algorithm is presented in this paper. The security of improved scheme has been analyzed by ProVerif. Thorough analysis shows that the presented scheme can provide stronger security and slight lower computation at client than Das’s protocol. What’s more, it can overcome repeat registered attack and achieve sensor node’s identity anonymity protection.
A conceptual similarity and correlation discrimination method based on HowNet
Authors: Ding Yunnian , Jia Yangli , Zhang Zhenling
Published: March 2020

The similarity and correlation analysis of word concepts has a wide range of applications in natural language processing, and has important research significance in information retrieval, text classification, data mining, and other application fields. This paper analyzes and summarizes the information of sememes relationship through the definition of words in HowNet and proposes a method to distinguish the similarity and correlation of words. Firstly, using a combination of the part of speech and sememes to distinguish the similarity and correlation between words concept. Secondly, the similarity and correlation calculation results between vocabulary concepts are used to further optimize the judgment results. Finally, the similarity and correlation distinction and discrimination between vocabulary concepts are realized. The experimental results show that the method reduces the complexity of the algorithm and greatly improves the work efficiency. The semantic similarity and correlation judgment results are more in line with the human intuitive experience and improve the accuracy of computer understanding of natural language. which provides an important theoretical basis for the development of natural language.
Aircraft rerouting and rescheduling in multi-airport terminal area under disturbed conditions
Authors: Ma Yuanyuan , Hu Yuxin , Li He , Yan Yongjie , Yin Jianan
Published: March 2020

The disturbances, caused by resource competition, weather changes, and demand uncertainties, frequently occur and result in obvious fluctuations (e.g., the increase or decrease of demand and capacity) in demand and capacity. This work addresses the problem of aircraft rerouting and rescheduling in presence of disturbances, characterized by the increase or decrease of demand and capacity, at a multi-airport terminal maneuvering area (TMA). A multi-objective optimization model is proposed to minimize the total flight delays and total extra flying time, considering the aircraft wake turbulence separation, runway operation rules, air traffic control regulations, scheduling time windows, and airport/airspace capacity, etc. Based on the non-dominated sorting genetic algorithm (NSGA-II), we designed an efficient evolutionary algorithm to solve the proposed model and search the Pareto solutions. Five scenarios are designed to analyze and compare the operation performance under normal and disturbed conditions, using the classic First-Come-First-Served (FCFS) and optimized scheduling (OPTS) methods. A case study is conducted for Shanghai Pudong and Hongqiao Airports, and the computational results show that, compared with the FCFS method, the proposed OPTS method significantly performs a overall better performance in minimizing total flight delay and total extra flying time, while slightly inferior in optimizing the delay and extra flying time of one single flight.
Research on GPR image recognition based on deep learning
Authors: Gong Zhimin , Zhang Huaiqing
Published: March 2020

It is difficult for traditional image recognition methods to accurately identify ground penetrating radar (GPR) images. This paper proposes a deep-learning based Faster R-CNN algorithm for the automatic classification and recognition of GPR images. Firstly, GPR images with different features were obtained by using gprMax, a professional GPR simulation software. Then, the feature of the target in the image was taken as the recognition object and the data set was made. Finally, Faster R-CNN’s recognition ability of GPR images was analyzed from various accuracy, average accuracy and other indicators. The results showed that Faster R-CNN could successfully identify GPR images and accurately classify them, with an average accuracy rate of 93.9%.
Novel image detector of fixed-valued impulse noise with high noise intensity
Authors: Hu Haijiang , Song Shaojing , Gan Weifei
Published: March 2020

Impulse noise is a common noise in digital image processing, which includes the fixed-valued impulse noise and the random-valued impulse noise. A novel method is proposed to detect the fix-value impulse that uses the deviation of slant angle as test object to recognize whether a noise candidate is impulse noise pixel. Distinguishing the average method and medium method, the method uses the new test object to detect the impulse noise. The mathematical model and the detection algorithm of this method are stated and analyzed, and the experiments show the performance of this method under the different circumstance. The biggest advantage of this method is to detect the fixed-valued impulse noise correctly and robustly under the different noise intensity that is up to 0.95.
Multi-source fault identification based on combined deep learning
Authors: Xing Dongqiu , Chen Rui , Qi Lihua , Zhao Jing , Wang Yi
Published: March 2020

This study establishes a multi-source fault identification method based on a combined deep learning strategy to identify a multi-source fault effectively in the fault diagnosis of complex industrial systems. This framework is composed of feature extraction and classifier design. In the first state, the signal is transformed to the time-frequency domain and the time-frequency feature is learned using stacked denoising autoencoders. A learning method that consists of unsupervised pre-learning and supervised fine-tuning is used to train this deep model. In the second state, a model for an ensemble multiple support vector machine classifier is created to recognize fault information. Ten types of rolling bearing signals were adopted in a simulation experiment to validate the effectiveness of the proposed framework. The results demonstrate that the joint model helps to obtain higher recognition accuracy.
Design of dancing robot control system based on STM32
Authors: Xu Liyan , Tan Xiaodong , Liu Shengyun
Published: March 2020

Dancing robot control system for children’s entertainment is introduced. In order to achieve better interaction, this robot use the ARM core chip STM32 as the control core, Bluetooth module as the means of wireless communication, and smart phones as the face display screen and motion controller of dance robots. Experimental results show that the robot is stable, it can work given dance actions. The robot is good operable and maintainable.
Prognostics and health management technology for radar system
Authors: Lyu Yongle , Pang Zhuo , Zhou Chuang , Zhao Peng
Published: March 2020

Information-based war in the future has a higher requirement to the maintenance and support ability of radar system. Prognostics and Health Management(PHM) technology represents the research hotspot of maintenance system, and following key techniques need to be resolved to research on the radar PHM technology such as the acquirement and selection of health information and fault signs of a radar’s electronical components, mass data warehousing and mining, fusion of multi-source test data and multi-field characteristic information, failure model building and forecasting, automatic decision-making on maintenance, and at the same time improving the self built-in test abilities of radar’s components based on the optimization of Design For Testability(DFT). The radar PHM technology has the trend of “built-in to integrate”, “together with DFT” and “long-distance and distributed”. However, subjected to radar’s complexity and current PHM technique level, radar PHM engineering still meets many challenges, but has bright future.
Continuous instinct control for powered knee-ankle prostheses
Authors: Shen Kaixin , Wei Qing , Huang Yongshang , Ma Hongxu
Published: March 2020

In order to improve the life quality of lower extremity amputees, many researchers have studied the powered knee-ankle prosthesis. Various parameters must necessarily be adjusted for the finite state machine impedance model method. Hybrid zero-dynamic (HZD) assumptions are ideal, and with this method measurement information of existing sensors can be limited. The virtual constraint method offers better comprehensive performance at present and can realize the continuous control for the whole gait cycle. The problem with virtual constraint is mainly the selection of phase variables. The joint trajectory of the virtual constraint is derived from a healthy individual, but the joint trajectory of the amputee’s normal walking is difficult to obtain. In response to the above problems, this paper proposes an instinctive human joint trajectory, selecting the phase variable associated with the hip joint angle and angular velocity. The Fourier transform solves the expression of the joint trajectory, and the virtual constraint unifies the control method of the entire gait cycle. The simulation results prove the feasibility of the scheme.
Ground simulation research on the super large moment of inertia of the space transfer manipulator
Authors: Zhang Wei , Wang Hongxin , Jia Weijian , Ding Lin , Cheng Ying
Published: March 2020

During the construction of the space station, the cabin is driven by the transposition manipulator in space. Because of the large mass and volume of the cabin, which is not less than 22 tons, there will be emerge a large moment of inertia in the transposition process, which is not less than . Therefore, a full physical experimental method is designed to simulate the moment of inertia of the transposition manipulator in space on the ground. In this paper, the three-dimensional model of the whole physical loading method is built, and the dynamic model is built by using the Lagrange equilibrium method. The minimum values of the moment of inertia applied by this method to the shoulder joint and the wrist joint of the space manipulator are calculated as and respectively. The simulation through Adams show that the error of the method to the shoulder joint and the wrist joint of the manipulator is increased by 4.4% and 5.59% respectively compared with that of the dynamics, that is to say no matter in numerical value or error, all physical experiment methods meet the requirements of ground test.
Heavy overload forecasting of distribution transformers based on neural network
Authors: Xie Haining , Tian Yingjie , Zhu Wei , Hu Zhongyu
Published: March 2020

The overload management is significance component in distribution network operation and maintenance to improve electricity service. According to the periodic characteristics of the electric load, this paper designs a new method to identify and predict the heavy overload states and highlight the dates where the distribution transformer most likely heavy overload through the historical load rate and meteorological data. The Attention-GRU neural network is introduced to predict electric load rate of the highlight dates to improve the prediction efficiency. In comparison with the performances traditional LSTM in prediction of distribution transformers, results show that the new method has higher accuracy and efficiency in predicting highlight dates’ load rates.
Neurophysiologen im Nationalsozialismus – Hans Berger, Paul
Hoffmann, Richard Jung und Alois E. Kornmüller
Authors: Baumann Timo , Sparing Frank , Martin Michael , Fangerau Heiner
Published: March 2020

Dies ist der zweite Teil der Studie „Beziehungen ausgewählter
Neurophysiologen zum Nationalsozialismus“. Hier werden die vier
wichtigen Neurophysiologen Hans Berger, Paul Hoffmann, Richard Jung und
Alois E. Kornmüller sowie ihr Wirken in der Zeit des
Nationalsozialismus näher vorgestellt.
Determinanten der kognitiven Entwicklung bei Kindern – Ergebnisse des Mann-Zeichen-Tests aus der Vorschuluntersuchung
Authors: Braig Stefanie , Fischer Nora , Freudenmann Matthias , Gonser Theodor , Genuneit Jon , Kolassa Iris-Tatjana , Rothenbacher Dietrich
Published: March 2020

Ziel der Studie Bestimmung von Determinanten und Einflussfaktoren der Wahrnehmungsentwicklung bzw. der kognitiven Entwicklung anhand des Mann-Zeichen-Tests bei Vorschulkindern.

Methodik Datengrundlage bildeten Elternfragebögen, die im Rahmen einer Geburtskohortenstudie (Ersterhebung 2000/2001 in Ulm) eingesetzt wurden mit Folgeerhebungen im zweiten, dritten, vierten und sechsten Lebensjahr. Die kognitive Entwicklung wurde anhand von Zeichnungen von n=298 Kindern anlässlich der Schuleingangsuntersuchung (mittleres Alter=5,8 Jahre, SD=0,4) mithilfe des Mann-Zeichen-Tests gemessen. Bi- und multivariable lineare Regressionsanalysen dienten zur Analyse von möglichen Einflussfaktoren.

Ergebnisse Bei Jungen fand sich eine positive Assoziation zwischen der einer hohen Schulbildung des Vaters und der kindlichen kognitiven Entwicklung (Regressionskoeffizient b, p-Wert: 6,65, p=0,018). Tendenziell konnte darüber hinaus ein negativer Zusammenhang des Besuchs eines Kinderhorts (b=− 0,18/Monat, p=0,074) sowie von allergischen Erkrankungen (b=− 6,02, p=0,075) und der kognitiven Entwicklung gezeigt werden. Ein Fernseh-/Videokonsum von mehr als 30 Min./Tag im Alter von 4 Jahren (b=− 9,37, p=0,005) war deutlich negativ mit den kindlichen kognitiven Fähigkeiten assoziiert. Bei Mädchen zeigten sich Hinweise auf eine negative Assoziation zwischen einer hohen mütterlichen Schulbildung (b=− 4,43, p=0,091) sowie eine positive Assoziation zwischen allergischen Erkrankung und der kognitiven Entwicklung (b=6,42, p=0,075). Eine gleichzeitige Adjustierung für alle relevanten Kovariablen führte sowohl bei Jungen als auch bei Mädchen zur Abschwächung der Assoziationen, jedoch blieb bei Jungen der Zusammenhang der väterlichen Bildung und des Fernseh-/Videokonsums mit den kindlichen kognitiven Fähigkeiten bestehen.

Schlussfolgerung Die Studie zeigt modifizierbare Faktoren auf, die mit der kognitiven Fähigkeit von Jungen und Mädchen im Alter von 6 Jahren in Zusammenhang stehen, insbesondere der frühkindliche Medienkonsum bei Jungen.
Thoracic Aortic Emergencies: Presenting Pathologies and Treatment Strategies
Authors: Sheeran Daniel P. , Zelickson Adam M. , Wilkins Luke R. , Angle J. Fritz , Williams David M. , Khaja Minhaj S.
Published: March 2020

Thoracic aortic emergencies reflect a wide range of etiologies, pathologic processes, and clinical presentations. Accurate identification with an appropriate treatment algorithm is best accomplished in a multidisciplinary setting with interventional radiologists, vascular surgeons, and cardiothoracic surgeons. While knowledge of thoracic stent graft equipment and technique is essential in the treatment of thoracic aortic emergencies, many clinical settings may employ alternative treatment techniques. This article will review the most common thoracic aortic emergencies and treatment strategies.
Gastrointestinal Bleeding on Call: Questions and Answers and One Person's Opinions
Authors: Funaki Brian
Published: March 2020

Gastrointestinal (GI) bleeding represents one of the more morbid forms of hemorrhage that interventional radiologists deal with on an on-call basis. Bleeding from the GI tract takes many forms and has many etiologies. While venous bleeds from varices are often treated emergently with placement of a transjugular intrahepatic portosystemic shunt, arterial hemorrhages are treated most effectively with embolization procedures. Embolization must be performed in specific ways, however, in an effort to decrease the risk of bowel ischemia; this also requires choosing the right patients in whom to perform embolization procedures. This article will provide a discussion on when to perform embolization and how, what to do with specific patient populations such as those with coagulopathy, and which patients should be considered for emergent treatment versus those that can be postponed.
Correction to: Opaque: an empirical evaluation of lobbying transparency in the UK
Authors: McKay Amy Melissa , Wozniak Antal
Published: March 2020

After the article was submitted for review, we continued improving the data. We performed a second attempt to merge groups in the lobby register with groups mentioned in ministerial meetings reports.
Modulated wall motion approach for augmenting slug flow heat transfer between two micro-parallel plates
Authors: Vivekanand S. V. B. , Raju V. R. K.
Published: March 2020

Liquid–liquid slug flow heat transfer in microchannels has been an interesting topic of research to many researchers. However, the heat transfer studies available in the existing literature deal with stationary walls of the microchannels. In the present work, a modulated motion is prescribed to the walls of the channel in the transverse direction during oil–water slug flow between micro-parallel plates. The influence of frequency and amplification factor of the modulated wall motion as well as capillary number on the droplet shape, film thickness, pressure drop, and heat transfer rate under uniform wall heat flux conditions is investigated computationally. The heat transfer results for the modulated wall motion case show a significant improvement over liquid-only flow and slug flow without any wall motion. Besides, the effect of slug length on the heat transfer has also been discussed for both modulated and unmodulated wall motions of the channel. A mean absolute deviation of 2%–75% in the pressure drop obtained from the numerical studies and existing semi-empirical models for stationary walls for the studied Capillary numbers is observed. This suggests that a better formulation is required for the pressure drop model. In addition, although Nusselt numbers are found to be in reasonable agreement with the existing model for stationary walls, requirement for the formulation of a generalized model considering the effect of wall oscillations is also suggested. This study proposes a new perspective for heat dissipation in micro-scale channels and promotes flow and heat transfer studies, which could bring benefits to relevant applications.
Realization of 5he2 with graphene quantum Hall resistance array
Authors: Park Jaesung , Kim Wan-Seop , Chae Dong-Hun
Published: March 2020

We report on the realization of 10 quantum Hall devices in series fabricated using epitaxial graphene on silicon carbide. Precision measurements with a resistance bridge indicate that the quantized Hall resistance across an array at a filling factor of 2 is equivalent to 5he2 within the measurement uncertainty of approximately 4 × 10−8. A quantum Hall phase diagram for the array shows that a metrological quantization of 5he2 can be achieved at the magnetic field of 6 T and a temperature of 4 K. This experiment demonstrates the possibility of timely unchangeable resistance reference in various ranges in relaxed experimental conditions.
Effects of LaScO3 doping on structure, dielectric, and piezoelectric properties of K0.5Na0.5NbO3 piezoceramics
Authors: Dwivedi Sushmita , Pareek Tanvi , Badole Manish , Ahmed Shadab Ali , Kumar Sunil
Published: March 2020

Lead-free (1 − x)K0.5Na0.5NbO3–xLaScO3 (abbreviated as KNN–LSO) ceramic with (x = 0–0.10) was prepared via the solid-state synthesis route. The changes in the microstructure, crystal structure, dielectric, piezoelectric, and ferroelectric properties were analyzed for all compositions. The Rietveld refinement of powder x-ray diffraction suggested the variation in the crystal structure from orthorhombic for pure KNN to a mixed phase of tetragonal and orthorhombic for x ≥ 0.03. Temperature-dependent dielectric measurements also confirmed the change in the crystal structure with the increase in the LSO content, and the tetragonal to cubic TT-C phase transition temperature was found to shift toward room temperature. Interestingly, the temperature of the orthorhombic to tetragonal (TO-T) phase transition remained almost invariant in the LSO-doped sample (x ≥ 0.02), and a frequency dispersion in TO-T, typical for a relaxor ferroelectric, was observed. The frequency variation of temperature of the dielectric maximum Tm (∼426 K at 10 kHz and ∼444 K at 1 MHz) for x = 0.05 sample was fitted using the Vogel–Fulcher relation. This was further corroborated by the appearance of a slim hysteresis in the polarization–electric field plot. The impedance studies suggested that non-Debye relaxation and conduction mechanisms were associated with the thermal activation of oxygen vacancy that was rationalized by similar values of activation energy obtained from Arrhenius fitting for all samples. Current–voltage (I–V) measurements illustrate the reduction in room temperature DC conductivity with the increase in LSO doping. The highest room temperature piezoelectric charge coefficient (d33) value of 130 pC/N was observed for the composition corresponding to x = 0.01.
Interface stabilization via lithium bis(fluorosulfonyl)imide additive as a key for promoted performance of graphite‖LiCoO2 pouch cell under −20 ○C
Authors: Pham Hieu Quang , Chung Gyeong Jun , Han Jisoo , Hwang Eui-Hyung , Kwon Young-Gil , Song Seung-Wan
Published: March 2020

The effects of lithium bis(fluorosulfonyl)imide, Li[N(SO2F)2] (LiFSI), as an additive on the low-temperature performance of graphite‖LiCoO2 pouch cells are investigated. The cell, which includes 0.2M LiFSI salt additive in the 1M lithium hexafluorophosphate (LiPF6)-based conventional electrolyte, outperforms the one without additive under −20 °C and high charge cutoff voltage of 4.3 V, delivering higher discharge capacity and promoted rate performance and cycling stability with the reduced change in interfacial resistance. Surface analysis results on the cycled LiCoO2 cathodes and cycled graphite anodes extracted from the cells provide evidence that a LiFSI-induced improvement of high-voltage cycling stability at low temperature originates from the formation of a less resistive solid electrolyte interphase layer, which contains plenty of LiFSI-derived organic compounds mixed with inorganics that passivate and protect the surface of the cathode and anode from further electrolyte decomposition and promotes Li+ ion-transport kinetics despite the low temperature, inhibiting Li metal-plating at the anode. The results demonstrate the beneficial effects of the LiFSI additive on the performance of a lithium-ion battery for use in battery-powered electric vehicles and energy storage systems in cold climates and regions.
Generalized optical design of two-spherical-mirror multi-pass cells with dense multi-circle spot patterns
Authors: Cui Ruyue , Dong Lei , Wu Hongpeng , Chen Weidong , Tittel Frank K.
Published: March 2020

We report a set of practical multi-circle spot patterns produced by two-spherical-mirror multi-pass cells (MPCs). Such a set of intricate spot patterns takes full account of the evolution and deformation of spot shapes caused by aberrations on two spherical mirror surfaces by means of a multi-ray calculation model, thus avoiding spot overlaps and reducing an etalon effect. An eight- and nine-multi-circle spot pattern was demonstrated experimentally in order to verify the validity of the calculated results. Furthermore, a 2f spectrum measurement of ambient methane was performed using the eight-multi-circle spot pattern MPC to verify the practicability. An approach to search for multi-circle spot patterns in a two-spherical-mirror MPC is discussed in detail. A set of dense spot patterns results in sensitive, low-cost, compact trace gas sensors based on MPCs, which can be used to implement a large-scale deployment of distributed sensor networks for monitoring pollutants or to realize handheld mobile sensor devices for safety inspection, leakage detection, and medical diagnostics.
Determination of electrical characteristics and temperature of PV modules by means of a coupled electrical-thermal model
Authors: Hanifi Hamed , Regondi Simone , Jaeckel Bengt , Schneider Jens
Published: March 2020

Photovoltaic (PV) modules are commonly tested under standard test conditions. However, the performance of the PV module is highly dependent on the location, climate condition, and sun spectrum. Simulation is one of the inexpensive and practical approaches to estimate the performance of PV modules under different climatic conditions. Modeling of PV modules can be complex because different physical phenomena must be coupled and interact with each other. There are several existing multi-physic models, but they are either complex such as numerical models or highly simplified with a lot of assumptions. In this work, we introduce a thermal-electrical model to evaluate the performance of PV modules under different climate conditions based on a previously developed optical-electrical model. The model calculates the electrical parameters and temperature of the PV module after the module reaches the steady-state condition. The temperature, heat flow of all layers of the module, and the heat transfer thermal resistances can be determined. Comparison of the simulation and experimental results shows a deviation of around 1%, which indicates that the simulation and experimental results are in good agreement.
Tracking the flapping motion of flow separation using pointwise measurement
Authors: Fang Xingjun , Tachie Mark F.
Published: March 2020

In recent investigations of the unsteadiness of flow separation, time-resolved whole-field information, such as the temporal variation of reverse flow area and proper orthogonal decomposition modes, is commonly used to quantify the flapping motion of separation bubbles. In the present study, we explore the possibility of tracking the flapping motion of flow separation using only pointwise measurements. A generalized framework for designing the optimal number and positions of measurement points is presented and assessed using time-resolved particle image velocimetry measurement data for turbulent flow separations induced by a broad range of two- and three-dimensional surface-mounted bluff bodies. Two models are proposed to approximate the temporal variation of reverse flow area over the bluff bodies. These two models require only the mean reattachment length, mean velocity at the body height in the oncoming flow, and time-resolved single- or two-point measurements of streamwise velocity. The optimal location for the single-point model is in the rear part of the mean separation bubble around the highest elevation of the mean separating streamline. While the single-point model predicts the temporal variation of reverse flow area reasonably well, it consistently misidentifies the subdominant frequency of reverse flow area as the dominant one. For the two-point model, one measurement point is in the rear part of the mean separation bubble and the other measurement point is slightly downstream of the mean reattachment point. The two-point model reproduces the temporal variation as well as the dominant frequency of reverse flow area remarkably well. Overall, the present study proposes a simple and reliable method to track the temporal variation of reverse flow area and holds promise for the future development of active closed-loop flow control based on real-time flapping motion of separation bubbles.
An artificial site provides valuable additional habitat to migratory shorebirds in a tropical harbour
Authors: Lilleyman Amanda , Rogers Danny I. , Jackson Micha V. , Fuller Richard A. , O'Brien Gavin , Garnett Stephen T.
Published: March 2020

Migratory shorebirds are declining in all transequatorial flyways, most rapidly in the East Asian–Australasian Flyway. Population trends for shorebirds have been derived at a flyway and continental scale, but changes at the local scale are less well understood. Here we compare trends in migratory shorebird populations using natural and artificial roost sites within a tropical harbour, examine possible drivers of change, and identify appropriate conservation management responses. Counts of 19 migratory shorebird species from 2010 and 2018 showed that total abundance increased at an average annual rate of 3.3% (95% CI=1.3–5.4%, P=0.001) across five natural roost sites. This was driven largely by increases in great knot, with most other species declining. At an artificial site in an adjacent shorebird area, total abundance increased at an average annual rate of 14.5% (95% CI=10.5–18.6%, P ≤ 0.000), with few species declining. These results suggest that there is a need to include both natural and artificial sites within shorebird conservation and management planning and that trends in different species can be driven by a combination of local and external drivers.
Visual pragmatics of abbreviations and otiose strokes in John Lydgate’sSiege of Thebes
Authors: Rogos-Hebda Justyna
Published: March 2020

This paper1 addresses the visual-pragmatic functions of the so-called common mark of abbreviation, or macron, in a section of BL Royal MS 18 D II (ff. 147v–162r) – one of the best known “deluxe” manuscripts containing Lydgate’s Siege of Thebes. Contextualised within the framework of visual pragmatics, or Pragmatics on the Page (Carroll et al. 2013), the manuscript in question is considered here as a visual text (Kendall et al. 2013) – one for which the readers construe the meaning through internalising the physical organisation of discourse. The paper attempts to unpack the ways in which the common mark of abbreviation, employed by the scribes as a visual-pragmatic marker, organises the discourse of the manuscript page on three levels of meaning: textual, interactional and metalinguistic (following Erman 2001). The pragmatic roles of the macron are then confronted with the visual forms and possible functions of its notorious graphic doppelgänger (i.e., the otiose stroke).
Local grammars and diachronic speech act analysis
Authors: Su Hang
Published: March 2020

This paper proposes a method that is designed to facilitate diachronic speech act analysis. The proposed method draws on the corpus linguistic concept of local grammar – an approach which seeks to account for, not the whole of a language, but one meaning or function only. Local grammar descriptions capture both formal and semantic regularities of speech act realisations, and local grammars offer a more reliable way to quantify speech act realisations across time. It is particularly in this respect that it is argued that a local grammar approach can be useful for diachronic speech act studies, which is demonstrated subsequently by tracing one particular speech act, namely “apology”, in a sample of the Corpus of Historical American English (coha).
Variational mean-fluctuation splitting and drift-fluid models
Authors: Tronci Cesare
Published: March 2020

After summarizing the variational approach to splitting mean flow and fluctuation kinetics in the standard Vlasov theory, the same method is applied to the drift-kinetic equation from Littlejohn’s theory of guiding-center motion. This process sheds a new light on drift-ordered fluid (drift-fluid) models, whose anisotropic pressure tensor is then considered in detail. In addition, current drift-fluid models are completed by the insertion of magnetization terms ensuring momentum conservation. Magnetization currents are also shown to lead to challenging aspects when drift-fluid models are coupled to Maxwell’s equations for the evolution of the electromagnetic field. In order to overcome these difficulties, a simplified guiding-center theory is proposed along with its possible applications to hybrid kinetic-fluid models.
Mapping of primary somatosensory cortex of the hand area using a high-density electrocorticography grid for closed-loop brain computer interface
Authors: Kramer Daniel R , Lee Morgan B , Barbaro Michael F , Gogia Angad S , Peng Terrance , Liu Charles Y , Kellis Spencer , Lee Brian
Published: March 2020

Objective. The ideal modality for generating sensation in sensorimotor brain computer interfaces (BCI) has not been determined. Here we report the feasibility of using a high-density ‘mini’-electrocorticography (mECoG) grid in a somatosensory BCI system. Approach. Thirteen subjects with intractable epilepsy underwent standard clinical implantation of subdural electrodes for the purpose of seizure localization. An additional high-density mECoG grid was placed (Adtech, 8 by 8, 1.2 mm exposed, 3 mm center-to-center spacing) over the hand area of primary somatosensory cortex. Following implantation, cortical mapping was performed with stimulation parameters of frequency: 50 Hz, pulse-width: 250 µs, pulse duration: 4 s, polarity: alternating, and current that ranged from 0.5 mA to 12 mA at the discretion of the epileptologist. Location of the evoked sensory percepts was recorded along with a description of the sensation. The hand was partitioned into 48 distinct boxes. A box was included if sensation was felt anywhere within the box. Main results. The percentage of the hand covered was 63.9% (± 34.4%) (mean ± s.d.). Mean redundancy, measured as electrode pairs stimulating the same box, was 1.9 (± 2.2) electrodes per box; and mean resolution, measured as boxes included per electrode pair stimulation, was 11.4 (± 13.7) boxes with 8.1 (± 10.7) boxes in the digits and 3.4 (± 6.0) boxes in the palm. Functional utility of the system was assessed by quantifying usable percepts. Under the strictest classification, ‘dermatomally exclusive’ percepts, the mean was 2.8 usable percepts per grid. Allowing ‘perceptually unique’ percepts at the same anatomical location, the mean was 5.5 usable percepts per grid. Significance. Compared to the small area of coverage and redundancy of a microelectrode system, or the poor resolution of a standard ECoG grid, a mECoG is likely the best modality for a somatosensory BCI system with good coverage of the hand and minimal redundancy.
The effect of minimum thrust coefficient control strategy on power output and loads of a wind farm
Authors: Meng Fanzhong , Hou Lio Alan Wai , Liew Jaime
Published: March 2020

The use of down-regulation control strategies for wind turbines potentially optimises the wind farm performance. One of the promising strategies to minimise the wind farm loads and maximise the energy production is by down-regulating the upstream turbine with minimum thrust coefficient (Ct
). Nonetheless, a majority of minimum Ct
control studies is confined to fatigue load analysis of a single turbine. Therefore, this paper focuses on the investigation of the fatigue loads when operating turbines in a wind farm using a minimum Ct
control strategy, as well as extreme loads and energy production. The control strategy is implemented in the DTU Wind Energy controller coupled with the aero-elastic code, HAWC2. The Dynamic Wake Meandering model in HAWC2 is used so that the wake deficits generated from the upstream turbines realistically represent the minimum Ct
control strategy, as well as the interactions between wakes. The main contribution of this paper is to investigate the possible wind farm operating strategy using minimum Ct
control that leads to decrease the lifetime fatigue loads and increase the overall energy production of a wind farm due to the potential extended lifetime of certain wind turbine components.
A Metocean Reference Station for Offshore Wind Energy Research in the U.S.
Authors: Kirincich Anthony
Published: March 2020

There is an acute need for a long-term metocean reference site that will aid the near-term development of the offshore wind energy industry in the United States. High quality, multi-year observations of the wind resource at hub height in areas relevant to offshore wind energy are a requirement for reducing uncertainties in wind resource assessment, improving the fidelity of numerical models, assimilated products of the resource, and forecasts of near-term operational conditions and wind energy power production. Yet, few long-term data sets exist over the U.S. outer continental shelf that can provide accurate guidance for developers, turbine manufacturers, and utility operators. Thus, there is a critical need for robust, long-term data collection at a site having conditions representative of wind energy development areas. Additionally, an efficient and effective location for validating existing measurement systems and testing and verifying the accuracy of new sensors will play a key role in reducing uncertainty of estimates of the wind resource and reducing the cost and risk associated with offshore development.
Analysis of platform motions effect on the fatigue loads and aerodynamic unsteadiness in floating offshore wind turbines
Authors: AlShuwaykh Ahmed , Sharman Krish Thiagarajan
Published: March 2020

Floating platform motions introduce an additional level of complexity to the analysis models for floating offshore wind turbines. A series of simulations of the NREL 5MW wind turbine on a semi-submersible platform, in constrained (fixed) and free-to-move configurations, were done in OpenFAST software. Simulated time histories show that the platform motions increase the force and bending moment at the blade root by 3% and 7.4% respectively, while increase the same quantities at the tower base by 61.3% and 59.4%. The rainflow counting method was used to calculate the cyclic load and fatigue at the blade root and the tower base. The results show that the platform motions result in higher fatigue on the tower base in both design load cases, power production and parked. Platform motions show a lesser effect on the fatigue at blades root while the wind turbine is operational and negligible effect while idling. Understanding the relation between platform motions and the differences in loads and consequently the fatigue can provide better tools for wind turbine design.
Lidar-assisted yaw control for wind turbines using a 9-beam nacelle lidar demonstrator
Authors: Kawabata Hirokazu , Kogaki Tetsuya
Published: March 2020

In this study, the relationship between lidar-assisted yaw control and the measurement parameters was clarified using an experimental approach. To investigate the influence of the nacelle lidar configuration on lidar-assisted yaw control, two scan patterns and pulse-integration number settings were varied. The field tests revealed that, in most cases, the relative wind direction was reduced by the lidar-assisted control. The condition with high lidar data availability avoids the influence of noise, and the lidar-assisted control reduces the relative wind direction. These results suggest that in lidar-assisted yaw control, the management of the appropriate lidar data availability is more important than the scan pattern.
In-Blade Measurements of Cyclic Loading on Yawed Turbines with Trailing Edge Flap
Authors: Samara F. , Johnson D. A.
Published: March 2020

Wind turbines operate predominantly in relatively unsteady flow conditions and are typically misaligned with the incoming wind. Based on the literature review, controlling a section of the trailing edge of the turbine blade is found to reduce load fluctuations on wind turbine blades. Here, a detailed experimental setup describes a 3.5 m diameter wind turbine equipped with a trailing edge flap (TEF). The instrumentation of the compact blade was capable of measuring surface pressure and root bending moment, as well as controlling a TEF simultaneously and in time-resolved fashion. The blade is of constant pitch and chord of 178 mm while the TEF covers 20% of the chord and 22% of the 1.47 m aerodynamic blade span. The turbine was tested in a controlled wind generation facility large enough to house the turbine with less than 7% blockage. The wind turbine was tested for a range of tip speed ratios, blade pitch angles, flap angles and yaw cases. Although the turbine blade is capable of cyclically and dynamically change the blade pitch and flap angle, this paper only investigates constant pitch and flap angles. The results show that changes to the flap or pitch angle are capable of manipulating the coefficient of power, root bending moment and normal force coefficient. The results also show that the flap demonstrates similar control authority to that of the pitch system with the flap occupying just 4% of the blade surface area without reducing the power output of the turbine.
The curled wake model: equivalence of shed vorticity models
Authors: Martínez-Tossas Luis A. , Branlard Emmanuel
Published: March 2020

In this work, we explore the spanwise velocities in the wake of a yawed wind turbine. In the curled wake model, these motions are induced by a collection of vortices shed from the rotor plane. The direction of the vorticity generated by yaw is aligned with the main flow (streamwise) direction. The streamwise vorticity induces velocities in the spanwise directions. These are the motions responsible for creating the curled wake mechanism. In this work, we explore a more accurate formulation for this mechanism, using a vortex cylinder. Under certain assumptions, the new and original curled wake models yield the same mathematical formulation. Also, both models predict an elliptic distribution of vortex strength, where the main difference is the location of the vortices.
Characterization of turbulence under different stability conditions using lidar scanning data
Authors: Rai Raj K , Berg Larry K , Newsom Rob , Kaul Colleen M , Mirocha Jeffrey D , Choukulkar Aditya , Brewer Alan , Pichugina Yelena , Banta Robert
Published: March 2020

The spatiotemporal scales of turbulence in the boundary layer flow vary with the static stability of the atmosphere. For example, turbulence structures in unstable conditions are often found to be large and coherent, whereas the turbulent structures in stable conditions are relatively small and sporadic. To better understand the behavior of such turbulent structures under different atmospheric stability conditions in the lower atmosphere, herein, we use scanning lidar data collected over several months during the US Department of Energy’s second Wind Forecast Improvement Project (WFIP 2) in 2016. The radial velocity data from scanning lidar were gathered along the conical surface (PPI mode) and were analyzed using proper orthogonal decomposition (POD) and spectral energy methods. The results from these analyses show that the turbulent structures in daytime unstable conditions are different from those present during nighttime stable conditions in terms of amount of energy and coherent structures. The POD energy is distributed more evenly in all the higher spatial modes in the daytime unstable case compared to the nighttime stable case. Besides characterizing the turbulence in the flow, the lidar data were also used to compare the simulated flow field generated from the WRF-LES framework (Weather Research and Forecasting - large-eddy simulation) with the scanning lidar data. The results from both simulated and lidar scanned data show similar structures - orienting the streak-like structure along the mean wind. This indicates that the streak-like structures can exist in the real atmosphere during unstable atmospheric condition cases.
Mining algorithm for weighted FP-tree frequent item sets based on two-dimensional table
Authors: Li Yuanyuan , Yin Shaohong
Published: March 2020

FP-growth algorithm is a classic algorithm of mining frequent item sets, but there exist certain disadvantages for mining the weighted frequent item sets. Based on the weighted downward closure property of the weighted model, this paper proposed that the weighted support was recorded in the two-dimensional table. This method has saved the process to search for the first conditional pattern base by traversing the weighted FP-tree, improved the efficiency of the weighted frequent item sets generated.
Paragraph-Parallel based Neural Machine Translation Model with Hierarchical Attention
Authors: Zhang Yuqi , Liu Gongshen
Published: March 2020

Neural Machine Translation (NMT) has achieved great developments in recent years, but we still have to face two challenges: establishing a high-quality corpus and exploring optimal parameters of models for long text translation. In this paper, we first attempt to set up a paragraph-parallel corpus based on English and Chinese versions of the novels and then design a hierarchical attention model for it to handle these two challenges. Our encoder and decoder take segmented clauses as input to process the words, clauses, paragraphs at different levels, particularly with a two-layer transformer to capture the context from both source and target languages. The output of the model based on the original transformer is used as another level of abstraction, conditioning on its own previous hidden states. During this process, inter-clause and intra-clause contexts from source and target sides are introduced for translation prediction and both encoder and decoder can profit from contexts in complementary ways. Experimental results show that our hierarchical attention model significantly outperforms six competitive baselines, including ensembles.
A rescheduling approach based on genetic algorithm for flexible scheduling problem subject to machine breakdown
Authors: Nie Li , Wang Xiaogang , Liu Kai , Bai Yuewei
Published: March 2020

In this paper, a rescheduling approach based on genetic algorithm (GA) for solving the flexible scheduling problem subject to machine breakdown is proposed. In the proposed approach, event-driven rolling horizon rescheduling policy is employed to trigger the rescheduling procedure. Computational experiments are conducted on several benchmark data to prove the performance of the proposed approach. The results show that the proposed approach combines the rescheduling strategies of right-shift rescheduling and routing changing rescheduling to optimize the robustness and stability of rescheduling solution simultaneously.
A New Embedded Feature Selection Method using IBALO mixed with MRMR
criteria
Authors: Zhang Yu , Zhao Zhuanzhe , Zhao Shuaishuai , Liu Yongming , He Kang
Published: March 2020

In order to remove irrelevant data and increase classification accuracy in
feature selection, this paper proposed a new Embedded feature selection method
with gathering Minimal Redundancy Maximal Relevance (MRMR) criteria, Sequential
Forward Selection (SFS) and Improved Binary Ant Lion Optimizer (IBALO) together.
Totally, we use three different feature selection methods namely MRMR mixed with
Sequential Forward Selection (MS), MS mixed with Binary Ant Lion Optimizer
(MS-BALO), an improvement of MS-BALO. Experiments prove that the MS-IBALO method
proposed by this paper is efficient compared to MS and MS-BALO methods.
License Plate Character Segmentation Algorithm Based on Improved Regression Model
Authors: Yang Yuping
Published: March 2020

Many character segmentation algorithms in license plate recognition system are not very good for segmentation of complex characters, and there is a phenomenon of character sticking, which results in slow recognition speed and not very good recognition effect of the license plate with complex characters. For such problems, a segmentation algorithm based on the improved regression model on statistical characteristics is presented. Compared with other algorithms, experimental results show that less time is consumed and segmentation effect is better. The recognition rate of license plate can be improved effectively.