bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of D‐band frequency doubler with compact power combiner
Authors: Dou Jiangling , Jiang Shu , Xu Jinping , Wang Wenbo
Published: February 2017

The design and results of a D‐band frequency doubler using two parallelly mounted Schottky dual‐diode chips are presented, which is considered as a unit in the doubler design. The doubler features four Schottky anodes closely located at a compact region, being no need for additional power dividing and combining circuit. The purpose is to verify the feasibility of a simple and compact hybrid microwave integrated circuit (HMIC) circuitry for frequency doubling with a higher power‐handling capability in this band, and an effective fast method for designing the matching networks of the doubler. With an input driving power of about 20 dBm at the E‐band and bias voltage of 0 V, it delivers an output power of 6 ± 1 dBm across the band of 140–152 GHz and 2–4.7 dBm over the bands of 152–160 and 135–140 GHz.
W‐band waveguide filter based on large TM120 resonators to ease CNC milling
Authors: Shang Xiaobang , Lancaster Michael , Dong Yu‐Liang
Published: February 2017

A W‐band waveguide bandpass filter, based on coupled TM120 resonators, fabricated using CNC milling, is presented. TM120 resonators are superior to conventional TE101 resonators, in terms of having a larger size and reduced aspect ratio, which facilitates the fabrication process as well as allowing larger tolerances in the milling process. This type of resonator also offers a high unloaded quality factor, and ultimately yields a small insertion loss for the filter. A W‐band filter, with a centre frequency of 100 GHz and a fractional bandwidth of 6%, is designed using four TM120 resonators and constructed from three brass shims which directly fit to the waveguide flanges. This filter is measured to have a median passband insertion loss of 0.5 dB and a return loss better than 13 dB across the whole passband.
Differential substrate integrated waveguide bandpass filter with improved common‐mode suppression utilising complementary split‐ring resonators
Authors: Zhang Hao , Kang Wei , Wu Wen
Published: February 2017

A novel differential substrate integrated waveguide bandpass filter is proposed. The TE102‐mode cavities arranged on the symmetrical plane could efficiently reduce the common‐mode (CM) signal, meanwhile, transmitting the differential‐mode signal. Additional transmission zeros have been obtained by using cross coupling in the dual‐mode cavities. Moreover, by symmetrically etching complementary split‐ring resonators on the bottom layer of the substrate, the CM could be suppressed whereas differential signals are not affected. To verify the above design concept, a prototype operating at 8.07 GHz has been realised and shows the desired filtering performance.
Hybrid full‐wave/circuit modelling of spark gaps and its experimental validation
Authors: Fujita K. , Zhou J. , Pommerenke D.
Published: February 2017

A hybrid full‐wave and circuit model for spark gaps was constructed. The spark channel was modelled as a non‐linear time‐dependent resistor based on Rompe–Weizel's spark formula in SPICE. The linear full‐wave model of an air gap and other structures were simulated by the semi‐implicit finite‐difference time‐domain scheme based on the Newmark‐beta method. These two models were coupled and simultaneously solved in time domain. The coupled model was tested for different charged voltages and spark lengths, and also validated in comparison with measurements.
Speech enhancement based on mEMD‐VMD method
Authors: Upadhyay A. , Pachori R.B.
Published: February 2017

A novel and effective speech enhancement method is proposed for suppressing the white noise as well as non‐stationary acoustic noises. The proposed method employs the combination of variational mode decomposition (VMD) and empirical mode decomposition (EMD) methods. In this method, first EMD is used to decompose the noisy speech signal into intrinsic mode functions (IMFs). Further, the VMD is applied on summation of selected IMFs. The main contribution of the proposed method is the selection of IMFs based on Hurst exponent and further applying steps of VMD method. The proposed modified EMD‐VMD (mEMD‐VMD) method is suitable to reduce the low‐frequency noise as well as high‐frequency noise. The proposed method gives the better results in terms of speech quality and composite measures. The proposed study is performed on eight speech signals under additive white Gaussian noise, street noise, babble noise, and airport noise taken from NOIZEUS database.
3D printed 1.1 THz waveguides
Authors: Otter W.J. , Ridler N.M. , Yasukochi H. , Soeda K. , Konishi K. , Yumoto J. , Kuwata‐Gonokami M. , Lucyszyn S.
Published: February 2017

For the first time, 3D printed metal‐pipe rectangular waveguides (MPRWGs) have been demonstrated in the WM‐380 (500–750 GHz) and WM‐250 (750 GHz–1.1 THz) waveguide bands. The ultra‐high spatial resolution offered by the new RECILS additive manufacturing technology enables the precision fabrication of these prototype MPRWGs at such high frequencies. This enabling technology avoids the need for access to expensive microfabrication resources and, thus, opens up the terahertz spectrum to the low‐cost manufacture of passive components.
Mean arterial pressure‐embedded model for real‐time simulation and controller validation
Authors: Silva S.J. , Scardovelli T.A. , Martucci H.N. , Boschi S.R.M.S. , Silva A.P.
Published: February 2017

The lack of models for automatic control of mean arterial pressure (MAP), in real‐time, associated with variability in response to sodium nitroprusside infusion, makes it impossible to validate automatic MAP controllers. Therefore, this Letter presents a low‐cost innovative real‐time model to MAP. Therefore, the authors used a variation of the mathematical model of Slate, implemented in MATLAB®. The system was developed with the capabilities of Simulink® and deployed to a single‐board computer. The results showed that the embedded model presented an error <3% for a target MAP of 100 mmHg, allowing the use of this model, in real time, for validation of embedded MAP controllers.
Research and application on multi‐terminal and DC grids based on VSC‐HVDC technology in China
Authors: An Ting , Tang Guangfu , Wang Weinan
Published: February 2017

Voltage source converter (VSC)‐based high‐voltage direct current (HVDC) and multi‐terminal (MT)/DC grid technologies are the new HVDC transmission technologies after ultra‐high voltage alternative current (UHVAC) and UHVDC transmission technologies which have been widely used in China. The application of the new technologies has resulted in a rapid increase in the number of schemes in construction and planning worldwide. This has been stimulated by the greater level of functionality available from the VSC technology, which makes it suitable for a wide variety of applications. These include the integration of off‐shore wind farms, embedded links within AC networks and interconnectors, especially where the AC networks are relatively ‘weak’. VSC technology has renewed interest in MT DC systems, which may ultimately lead to wide area DC grids. This study outlines the research and application on MT and DC grids in China with respect to VSC‐HVDC key technologies and DC grid key technologies based on the presentation given in the International Workshop on Next Generation Power Equipment held on 23 September 2016 in Xian, China. The briefing details of the VSC‐HVDC projects constructed and to be constructed in China are summarised in this study.
Multiresolution acquisition scheme for the physical layer design of a direct sequence spread spectrum transequatorial HF ionospheric data link
Authors: Alsina‐Pagès Rosa Ma , Socoró Joan Claudi , Salvador Martí , Hervás Marcos
Published: February 2017

This study presents the final implementation of a multiresolution acquisition structure, designed and tested for a long‐distance ionospheric High Frequency link from Antarctica to Spain. It completes the receiver's physical layer design for this link of 12,760 km, improving the performance of the communications system. The goals of this proposal are to achieve a faster convergence, as well as a more robust and stable acquisition and demodulation. The multiresolution structure is based on least mean square adaptive filters. Acquisition is achieved when a filter converges to a decimated version of the Pseudo‐Noise sequence. Convergence parameters have been adjusted for best performance in the long‐haul time variant ionospheric channel. The information about channel's multipath dispersion is used to improve the direct sequence spread spectrum demodulation at the receiver. The results presented in this study are obtained from real data transmitted through the ionospheric Antarctic channel in the austral summer of 2008 and show the improvements in terms of stability, robustness and Bit Error Rate in the receiver. These improvements led us to choose this multiresolution acquisition structure for the receiver of the Antarctic HF system.
Finite‐gain stability from disturbance to output of linear delay systems via impulsive control
Authors: Li Ping , Liu Xinzhi , Zhao Wu , Zhong Shouming
Published: February 2017

This study studies how impulses affect the bounded behaviours of delay system with bounded disturbance. By employing the method of Lyapunov function, several criteria of finite‐gain stability from disturbance to output are established. It is shown that a linear delay differential system can be finite‐gain stabilised from disturbance to output using impulsive feedback control even there is an unstable matrix. Moreover, delay differential equations also maybe finite‐gain stable from disturbance to output under an appropriate sequence of impulses treated as disturbances. Two examples and simulations are also given to illustrate our results.
Model‐free predictive current control for three‐phase AC/DC converters
Authors: Lai Yen‐Shin , Lin Cheng‐Kai , Chuang Fu‐Pao , Yu Jen‐te
Published: February 2017

A novel model‐free predictive current control (MFPCC) approach for three‐phase AC/DC converters is proposed, which only measures the input currents and calculates their differences under different switching states. Existing model‐based predictive current control (MBPCC) methods are based on converter models and thus require the knowledge of input current, input and terminal voltages, resistance, and inductance. Compared to the MBPCC, the main advantages of the proposed MFPCC include eliminations of the converter model, multiplication operations, and tuning of system parameters. Simulation results show that the proposed MFPCC controls the input current slightly better than does the MBPCC. Experimental results are provided to validate the effectiveness of the proposed method, which are obtained from a three‐phase AC/DC converter under the specifications of 380 V output voltage, 220 V/AC input voltage, and 1000 W output power. The measured harmonics orders 2–19 are shown to meet the IEC61000‐3‐2 Class A standard under 1000 W of output power. To the authors’ best knowledge, it is the first MFPCC for such applications.
Compensation control of suspension force for LS‐BLPMSM
Authors: Zhu Huangqiu , Huang Jianbo
Published: February 2017

To overcome the difficulty in start‐up of bearingless permanent magnet synchronous motor (BLPMSM), a novel structure of line‐starting BLPMSM (LS‐BLPMSM) is presented in this study, which has the ability of self‐starting. First, the operation principle of the LS‐BLPMSM is expounded and the suspension operation condition is deduced. Since two sets of windings are arranged in the stator of bearingless motor, different pole‐pair cooperation between two sets of windings cause breaking or driving torque, and the theory of pole‐pair cooperation is analysed. Second, the interference of squirrel‐cage on suspension force magnetic field is studied based on the T‐type equivalent circuit model of the equivalent induction motor formed by the suspension force windings and squirrel‐cage bars, and a suspension force compensation strategy is presented. Finally, an experimental prototype with 2‐pole‐pair torque windings and 1‐pole‐pair suspension force windings is tested under different working conditions with the proposed control strategy. The rotation speed and the displacements in x and y axes are provided. The simulation and experimental results have shown that the motor has good rotation and suspension performance, and the validity and feasibility of this control strategy are confirmed.
Torque and state estimation for real‐time implementation of multivariable control in sensorless induction motor drives
Authors: Merabet Adel , Tanvir Aman A. , Beddek Karim
Published: February 2017

This study presents a strategy for estimating the states and the load torque to implement a feedback linearisation controller for induction motor drives. The multivariable control is carried out using input–output linearisation feedback law in order to track profiles of the rotational speed and the rotor flux amplitude. The unknown load torque is compensated by an estimator based on the speed error. The state estimation requires only the measurements of the stator voltages–currents. The estimation method is not invasive as no mechanical sensors are needed. Experimental platform equipped with sensors at the load side, for measuring the speed and the torque of the motor driven by the Opal‐RT real‐time system, was implemented to verify the accuracy of the proposed estimation method to implement the multivariable control.
Solution of reactive power optimisation including interval uncertainty using genetic algorithm
Authors: Zhang Cong , Chen Haoyong , Ngan Honwing , Liang Zipeng , Guo Manlan , Hua Dong
Published: February 2017

The reactive power optimisation (RPO) is generally used to design an optimal profile of the voltage and reactive power of power systems in the steady state for deterministic sets of demand loads and generation values, and it is a significant procedure in voltage control. However, the input data of a power system is actually uncertain in practise, which makes RPO an uncertain non‐linear programme. To address this problem, the input data were considered as intervals, and the RPO incorporating interval uncertainties model was proposed. To solve this model, the genetic algorithm was employed as the solution algorithm, where the reliable power flow calculation was used to judge the constraints of the model. The Pareto front was established as the solution of the proposed model since it has two objective functions, i.e. the midpoint and radius of real power losses. The application of this technique to the uncertain RPO was explained in detail. Two numerical results were analysed to demonstrate the effectiveness of the proposed method, especially in comparison with the previously proposed chance‐constrained programming method.
Method for calculating corona inception voltage of ultra‐high‐voltage direct current transmission lines with frequency‐domain characteristics of corona current
Authors: Liu Yingyi , Zhou Lijuan , Liu Yuanqing , Yuan Haiwen , Ji Liang
Published: February 2017

Corona inception voltage is of great significance for the design of ultra‐high‐voltage direct current transmission lines. In this study, based on the change rule of frequency‐domain characteristics of corona current, a new method for calculating corona inception voltage is proposed. First, corona current waveforms are collected through experiments and the range of measuring voltages is determined according to the frequency spectrum characteristics of corona current. Then, the curves representing the relationship between the change rate of corona current octave power and the voltage at different centre frequencies (6–20 kHz) are obtained through least‐square fitting. The voltage at which the fitted curve reaches the first peak value with the rise of voltage is identified as corona inception voltage. Finally, with the proposed method, the corona inception voltage for a six bundled conductor system in the biggest outdoor corona cage of the world is obtained. Combined with the experimental results of A‐weighted sound level of audible noise, the comparisons between the obtained corona inception voltage and that calculated with curve fitting method, curve fitting method and an audible noise‐based method prove that the proposed method is reasonable.
Variable time step application on hybrid eletromechanical–eletromagnetic simulation
Authors: Jardim Jorge , Salim Karen Caino de Oliveira , Santos Pedro Henrique Lourenço dos , Neto Carlos Alberto da Silva , Santos Marcelos Groetaers dos , Barros Henildo Medeiros de , Taranto Glauco N.
Published: February 2017

This study presents a new hybrid eletromechanical–eletromagnetic simulation implementation in which a variable time step with simultaneous solution of differential and algebraic equations are the methods used for network solution and numerical integration of the electromechanical dynamics. The variable time step imposes changes in the parallel communication protocol between the positive‐sequence phasor and three‐phase waveform simulation algorithms. Results demonstrate the methodology accuracy applied to a modified version of the IEEE 39‐bus test system.
Stochastic energy storage capacity model of EV parking lots
Authors: Guner Sitki , Ozdemir Aydogan
Published: February 2017

Electric vehicles, EVs, provide temporary distributed energy storage capacity for the evolving distribution grid. An aggregated storage capacity of multiple EVs is more meaningful for a distribution grid. Commercial car parks at metropolitan cities and parking lots (PLs) of hospitals, shopping centres, universities etc. are the potential areas that can be organised for these purposes. This study presents a distributed storage capacity formulation of an EV PL that can be used in distribution system reliability improvement. The storage capacity was determined by sequential Monte‐Carlo simulations. Real car arrival‐departure data provided by the PL authority of Istanbul, technical parameters (SoC of the batteries, battery capacity of EVs, charging and discharging rates), and some side‐specific probabilistic parameters (driver behaviour, mean transportation distance etc.) were used for realistic model development. Special attention was given to some critical time periods when the storage support was more crucial for the utility grid. Moreover, future expectations for city urban planning and for travel behaviour of the community were also included in the model. Finally, impacts of several important parameters on the storage capacity of the PL were determined through sensitivity analysis.
Optimal phasor measurement units placement for full observability of power system using improved particle swarm optimisation
Authors: Saleh Alaa Abdelwahab , Adail Ahmed S. , Wadoud Amir A.
Published: February 2017

Penetration of renewable, advanced metering capabilities, and the urge for situational awareness, all calls for power system state estimation (SE). The SE with phasor measurement units (PMUs) is a powerful technique for full system observability. The results of the SE are more accurate, when using PMUs with optimal locations in the complex power systems. In this study, a proposed technique for optimal PMUs placement is discussed and implemented. The optimal PMUs locations will be determined using improved particle swarm optimisation algorithm. This study also presented an optimisation solution technique for the problem of SE using the weighted least square method, improved and based on optimal PMUs placement. A numerical observability analysis is also presented to check the validity of the proposed technique in power system SE based on gain matrix factorisation. The technique applies to the standard IEEE 14‐, 30‐, and 118‐buses systems. The results showed high efficiency and good performance in power system SE when using optimal PMUs locations with full observability.
Hardware efficient multiplier‐less multi‐level 2D DWT architecture without off‐chip RAM
Authors: Wu Changkun , Zhang Wei , Jia Qi , Liu Yanyan
Published: February 2017

This study presents a multi‐level 2D discrete wavelet transform (DWT) architecture without off‐chip RAM. Existing architectures use one off‐chip RAM to store the image data, which increases the complexity of the system. For one‐chip design, line‐based architecture based on modified lifting scheme is proposed. By replacing the multipliers with canonic sign digit multipliers, a critical path of one full‐adder delay is achieved. As per theoretical estimate, for three‐level 2D DWT with an image of N × N size, the proposed architecture requires 123 adders, 66 subtracters, 167 registers, temporal memory of 7.5N words and input RAM of 3N bytes. The estimated hardware requirement shows that for the image size of 512 × 512 and three‐level DWT, the proposed architecture involves at least 14.1% less transistor‐delay‐product than existing architectures.
Parabolic transformation function‐based external cloak with finite and realisable material parameters
Authors: Rajput Archana , Srivastava Kumar Vaibhav
Published: February 2017

Non‐linear shape external cloak using a parabolic transformation function is proposed with finite material properties. A simple one directional folding operation is utilised that provides homogeneous material properties in the complementary region, and also eases the creation of anti‐object in the complementary region from an object present in the cloaked region. In the core region, the axial material parameter is spatially invariant and other parameters are spatially varying but possess finite value. Due to finite small material range and its one directional spatial variation, the proposed cloak even with discrete material properties in core region shows nearly zero scattering in contrast to earlier reported cloak. Further, off‐diagonal elements of the core constitutive tensors in the Cartesian coordinate system are removed by converting them to diagonal elements in the principal coordinate system. Thus, only three diagonal elements are needed in the principal coordinate system to create the core medium, which are finite and realisable using two‐dimensional metamaterials.
Rain attenuation over terrestrial microwave links in South Korea
Authors: Shrestha Sujan , Choi Dong‐You
Published: February 2017

Absorption of radio frequency signal by atmospheric rain and losses is prevalent at frequencies above 10 GHz. This study presents studies on rain attenuation at 18 and 38 GHz microwave link systems, which specifies the minimum performance parameters for terrestrial fixed service digital radio communication. The 3.2 km experimental link at 18 and 38 GHz are used for studying rain propagation effects. The received signal data for rain attenuation and rain rate were collected at 10 s intervals over a 3‐year period from 2013 to 2015. The record shows rain rate of about 50 mm/h and attenuation values of 33.38, 21.88 and 20.89 dB occurred for 0.01% of the time under 18 GHz horizontal, vertical and 38 GHz vertical polarisation, respectively. This study highlights the discussion and comparison of ITU‐R P.530‐16, Moupfouma, Da Silva Mello and Abdulrahman models. Relative error margin of about 71, 60, 38%; 64, 49, 42%; 3, 38, 42% were obtained for 0.1, 0.01, 0.001% of the time in 18 GHz horizontal, vertical and 38 GHz vertical polarisation, respectively, from ITU‐R P. 530‐16 which have been analysed along with suitable approach to characterise rain attenuation in microwave link whose efficiency have been compared with prominent rain attenuation models.
Design of shaped offset cable mesh reflector antennas considering structural flexible property
Authors: Zhang Shuxin , Du Jingli , Li Peng
Published: February 2017

Contoured beams are required in the next design period of cable mesh reflector antennas. This study presents a new approach for synthesising contoured beams by integrated structural‐electromagnetic optimisation concept. A multidisciplinary optimisation model is established from the viewpoint of interaction between structural and electromagnetic disciplines. The structural parameters are directly optimised to produce contoured beams. To consider the structural flexible property, sensitivity analysis of radiation pattern with respect to surface nodal displacements and further to structural parameters is performed in the approach. With both the information of structural and electromagnetic sensitivities, the optimisation model is expanded and solved by a sequential linear programming. Simulation results of a contoured beam covering the continental United States (CONUS) verify its effectiveness.
Performance assessment of short‐reach multi‐level pulse‐amplitude modulation transmission exploiting least‐mean‐square equalisation
Authors: Khaliq Muhammad Shoaib , Cantono Mattia , Straullu Stefano , Curri Vittorio
Published: February 2017

The authors study the performance of pulse‐amplitude modulation, with 2, 4 and 8 levels per symbol, for short reach applications with propagation over up to 2 km of standard single mode fibre. They consider the three modulation formats operated both at the same bit‐rate of 25 Gbps and at same symbol rate of 25 Gbaud, supposing 3.125% forward error‐correction overhead and bit error rate threshold of 10‐4. They analyse transmitters (Tx) and receivers (Rx) based on digital signal processing, including a training‐driven finite impulse response (FIR) filter equaliser set through the least‐mean‐square algorithm. They analyse the sensitivity impairments induced by a limited Tx/Rx electrical bandwidth and evaluate the minimum number of taps – and consequent latency – needed by the FIR equaliser to obtain sensitivity benefits.
Common mode voltage reduction in a three‐to‐five phase matrix converter fed induction motor drive
Authors: Rahman K. , Iqbal Atif , Al‐Emadi Nasser , Ben‐Brahim Lazhar
Published: February 2017

Multiphase power converters generate common mode voltage due to switching actions of the power switches. The resulting common mode current in multiphase motor drives flow through the bearing and shaft. Continuous flow of common mode current gradually weakens the performance of the drives. A space vector pulse width modulation (SVPWM) technique is developed to reduce Common mode voltage (CMV) in a three‐to‐five‐phase matrix converter‐based five‐phase induction motor drive system. The principle of CMV reduction lies in the selection of proper space vectors for implementation of SVPWM. The proposed technique achieves reduction in the CMV without affecting other performances, i.e. loss in output voltage, total harmonic distortion in the output voltages and currents. The common mode voltage is reduced by selecting a set of proper zero space vectors and placing them in a suitable position within a switching cycle. Using this approach, CMV is reduced by ∼30%. Simulation and experimental results are provided for a five‐phase induction motor drive fed using a three‐to‐five‐phase matrix converter.
Low component merged cells cascaded‐transformer multilevel inverter featuring an enhanced reliability
Authors: Jahan Hossein Khoun , Naseri Mersad , Haji‐Esmaeili Mohammad Mehdi , Abapour Mehdi , Zare Kazem
Published: February 2017

Requiring lots of components is the main demerit of multilevel inverters. This problem makes them expensive, bulky, and with a high possibility of failure. Therefore, the issue of components reduction in multilevel topologies is of great importance. Cascaded transformers multilevel inverter (CTMI) is a converter that employs only one DC‐source, thus it eliminates the need for several DC‐sources. Same as the other multilevel inverters, CTMI consists of lots of components. This disadvantage of CTMI has been resolved through a new reduced components topology introduced in the present work. This topology uses almost half the number of switching elements, such as power switch and gate driver, which are required to construct a conventional CTMI for the same output voltage levels. Furthermore, to the end of enhancing the reliability of CTMI, this paper, using Markov reliability evaluation approach and evaluating the reliability and the Mean Time To Failure (MTTF) of the converters, has investigated the reliability of both the conventional and the proposed structures. Additionally, in order to prove the feasibility and correctness of the suggested topology computer aid simulation results along with the experimental results have been provided.
Effects of two‐area variable inertia on transient stabilisation in interconnected power system with DFIG‐based wind turbines
Authors: Zhang Xiangyu , Fu Yuan , Wang Shuang , Wang Yi
Published: February 2017

This study investigates a novel operating method of the interconnected power grid to improve dynamic stability using variable inertia control of large wind farms. In this scheme, the system inertia is considered as an adjustable operating parameter which can be regulated for inter‐area power oscillation control and frequency support. Based on the linear state equations derived from a two‐area interconnected power system, the effect of the controlled inertia on power oscillation damping is evaluated theoretically considering the different cases of power feeding and receiving networks. The respective wind turbine variable inertia control strategies for the feeding and receiving regional networks are proposed to enhance both inter‐area power oscillation damping and frequency stability. A typical two‐area interconnected power system with a high 30% wind penetration is simulated, which consists of four conventional power plants and two doubly fed induction generator (DFIG)‐based wind farms. The results demonstrate that by using the proposed control scheme, the frequency stability and the inter‐area oscillation damping are both significantly improved for the more effective inertia support in the interconnected power system.
Outlier detection for wireless sensor networks using density‐based clustering approach
Authors: Abid Aymen , Kachouri Abdennaceur , Mahfoudhi Adel
Published: February 2017

Outlier detection (OD) constitutes an important issue for many research areas namely data mining, medicines, and sensor networks. It is helpful mainly in identifying intrusion, fraud, errors, defects, noise and so on. In fact, outlier measurements are essential improvements to quality of information, as they are not conforming to expected normal behaviour. Due to the importance of sensed measurements is collected via wireless sensor networks, a novel OD process dubbed density‐based spatial clustering of applications with noise (DBSCAN)‐OD has been developed based on the algorithm DBSCAN, as a background for OD. With respect to the classic DBSCAN approach, two processes have been jointly combined, the first of computing parameters, while the second concerns class identification in spatial temporal databases. Through both of these modules, one is able to consider real‐time application cases as centralised in the base station for the purpose of separating outliers from normal sensors. For the sake of evaluating the authors proposed solution, a diversity of synthetic databases has been applied as generated from real measurements of Intel Berkeley lab. The reached simulation findings indicate well that their devised method can prove to help effectively in detecting outliers with an accuracy rate of 99%.
Active mixing of immobilised enzymatic system in microfluidic chip
Authors: Lukyanenko Kirill A. , Belousov Kirill I. , Denisov Ivan A. , Yakimov Anton S. , Esimbekova Elena N. , Bukatin Anton S. , Evstrapov Anatoly A. , Belobrov Peter I.
Published: February 2017

Parameters for sample introduction, dried reagents dissolution and mixing with sample for bienzyme system NAD(H):FMN‐oxidoreductase and luciferase immobilised in microfluidic chip were successfully determined. Numerical simulations of reaction chamber geometry, flavin mononucleotide (FMN) escape from starch gel and mixing options were conducted to achieve higher sensitivity of bioluminescent reaction. Results of numerical simulations were verified experimentally. The active mixer for dried reagents was made from an electro‐mechanical speaker's membrane which was connected to the input of the chip. Such a mixer provided better efficiency than a passive mixing, and it is simple enough for use in point‐of‐care devices with any systems based on immobilised enzymes in chips.
Preparation and properties of natural rubber/chitosan microsphere blends
Authors: Ming‐zhe Lv , Li‐feng Wang , Lei Fang , Pu‐wang Li , Si‐dong Li
Published: February 2017

Chitosan microspheres were prepared by ion induction and chemical cross‐linking using water as the medium. Natural rubber/chitosan microsphere blends were then prepared by blending the chitosan microsphere suspension with natural rubber latex. An infrared spectrometer, particle size analyser, scanning electron microscope, surface contact angle analyser, thermogravimetric analyser, and differential scanning calorimeter were employed for structure and property characterisation. The results showed that the average particle diameter and the polydispersity index of chitosan microspheres were 323.8 nm and 0.283, respectively. The thermal stability and mechanical properties of natural rubber/chitosan blends were enhanced by introducing chitosan microspheres into natural rubber latex. The water contact angle was significantly decreased, from 94.64° to 55.47°, indicating improved hydrophilic properties for the natural rubber/chitosan film. The natural rubber/chitosan blends showed excellent antibacterial properties when the chitosan microsphere content was >4.00% w/w.
Relationship of Tumor Thickness with Neck Node Metastasis in Buccal Squamous Cell Carcinoma: An Experience at a Tertiary Care Hospital
Authors: Ahmed Sadaf , Junaid Montasir , Awan Sohail , Choudhary Moaz , Kazi Maliha , Masoom Aria , Khan Hareem
Published: February 2017

Introduction Squamous cell carcinoma is the most common malignancy of the head and neck, with the buccal mucosa being the most common site involved. Early locoregional metastasis is a hallmark of this disease, and early stage tumors may harbor metastatic nodes that are occult. Certain parameters can help identify high-risk patients for whom the pattern of occult nodal metastasis can be predicted. Tumor thickness is one such objective parameter.

Objective To determine the relationship of tumor thickness with neck node metastasis in squamous cell carcinoma of the buccal mucosa.

Methods A retrospective chart review of 102 patients with biopsy-proven squamous cell carcinoma of the buccal mucosa with N0 Necks was performed. All patients underwent tumor resection with neck dissection, and the tumor thickness was measured. Univariate and multivariate analyses were performed.

Results A total of 102 patients, of which 73.53% were males and 26.47% were females. The mean age of the patients was 49.3 ± 11.1 years. It was found that the risk of neck node metastasis in buccal squamous cell carcinoma increases 35.5 times for a tumor thickness ≥ 2 mm, and the risk of neck node metastasis in buccal squamous cell carcinoma decreases by 0.58 times for each centimeter decrease in tumor size, while the rate of occult neck lymph node metastasis was found to be 37%.

Conclusion We conclude that tumor thickness is significantly related with neck nodal metastasis in buccal squamous cell carcinoma, considering the age of the patient and the size of the tumor.
A Forefoot Strike Requires the Highest Forces Applied to the Foot Among Foot Strike Patterns
Authors: Hashizume Satoru , Yanagiya Toshio
Published: February 2017

Ground reaction force is often used to predict the potential risk of injuries but may not coincide with the forces applied to commonly injured regions of the foot. This study examined the forces applied to the foot, and the associated moment arms made by three foot strike patterns. 10 male runners ran barefoot along a runway at 3.3 m/s using forefoot, midfoot, and rearfoot strikes. The Achilles tendon and ground reaction force moment arms represented the shortest distance between the ankle joint axis and the line of action of each force. The Achilles tendon and joint reaction forces were calculated by solving equations of foot motion. The Achilles tendon and joint reaction forces were greatest for the forefoot strike (2 194 and 3 137 N), followed by the midfoot strike (1 929 and 2 853 N), and the rearfoot strike (1 526 and 2 394 N). The ground reaction force moment arm was greater for the forefoot strike than for the other foot strikes, and was greater for the midfoot strike than for the rearfoot strike. Meanwhile, there were no differences in the Achilles tendon moment arm among all foot strikes. These differences were attributed mainly to differences in the ground reaction force moment arm among the three foot strike patterns.
Soft power: the origins and political progress of a concept
Authors: Nye Joseph
Published: February 2017

Power is the ability to affect others to get the outcomes one prefers, and that can be accomplished by coercion, payment, or attraction and persuasion. Soft power is the ability to obtain preferred outcomes by attraction rather than coercion or payment. This anecdotal comment recounts the origins of the concept as an analytical tool, and its gradual development as an instrumental concept used in political discourse in Europe, China and the United States. This article is published as part of a collection on soft power.
Geodesic acoustic modes with poloidal mode couplings ad infinitum
Authors: Singh Rameswar , Gürcan Ö. D.
Published: February 2017

Geodesic acoustic modes (GAMs) are studied including all poloidal mode (m) couplings within a drift reduced Braginskii framework. An exact analytical formula for GAM frequency is given within the toroidal Hasegawa Mima model with the full finite larmor radius effect and poloidal mode couplings ad infinitum using a scalar continued fraction formulation, which results from reduction of the semi-infinite chain of interactions that is obtained from the nearest neighbor coupling pattern due to geodesic curvature. This pattern can be described by a semi-infinite chain model of the GAM with the mode-mode coupling matrix elements proportional to the radial wave number kr. In the more general case of multi-field description of the GAM, the infinite chain can be reduced to a renormalized bi-nodal chain with a matrix continued fraction formulation. The convergence study of the linear GAM dispersion with respect to kr and the m-spectra confirms that the coupling beyond m = 1 is sustained only when kr ≠ 0 and the higher m couplings become important with increasing kr and increasing ion to electron temperature ratio τi.
Reconstruction of turbulence radial wave number spectra based on the multi-frequency microwave Doppler backscattering data
Authors: Gusakov E. Z. , Irzak M. A. , Popov A. Yu. , Khitrov S. A. , Teplova N. V.
Published: February 2017

An analytical treatment of radial correlation Doppler reflectometry (RCDR) within the framework of a model taking into account the two-dimensional probing wave propagation and scattering is performed. A procedure for the reconstruction of the turbulence radial wavenumber spectra from RCDR data is proposed and numerically justified for the real geometry of reflectometry experiments in large and modest-scale fusion plasmas.
Development of ultrafast time-resolved dual-comb spectroscopy
Authors: Asahara Akifumi , Minoshima Kaoru
Published: February 2017

Ultrafast time-resolved dual-comb spectroscopy (TR-DCS) has been demonstrated, which enables direct observations of transient responses of complex optical spectra by combining dual-comb spectroscopy with the pump–probe method. TR-DCS achieves two-dimensional spectroscopy with a wide dynamic range for both the temporal and frequency axes. As a demonstration, we investigated the femtosecond relaxation dynamics of a photo-excited InGaAs saturable absorber in the near-infrared frequency region. The transient response of the interferogram was successfully obtained, and both the amplitude and phase spectra of the dynamic complex transmittance were independently deduced without using the Kramers-Kronig relations. A high phase resolution in the order of milliradian was achieved by suppressing the effect from the slow phase drift caused in the experimental system. Our proof-of-principle experiment promotes a pathway to coherent, highly accurate, and multi-dimensional pump–probe spectroscopy using the optical frequency comb technology.
Designing an efficient rectifying cut-wire metasurface for electromagnetic energy harvesting
Authors: Oumbé Tékam Gabin T. , Ginis Vincent , Danckaert Jan , Tassin Philippe
Published: February 2017

Electromagnetic energy harvesting, i.e., capturing energy from ambient microwave signals, may become an essential part in extending the battery lifetime of wearable devices. Here, we present a design of a microwave energy harvester based on a cut-wire metasurface with an integrated PN junction diode. The cut wire with a quasistatic electric-dipole moment is designed to have a resonance at 6.75 GHz, leading to a substantial cross-section for absorption. The external microwaves create a unidirectional current through the rectifying action of the integrated diode. Using an electrical-circuit model, we design the operating frequency and the resistive load of the cut wire. Subsequently, by optimizing our design using full-wave numerical simulations, we obtain an energy harvesting efficiency of 50% for incident power densities in agreement with the typical power density of WiFi signals. Finally, we study the effect of connecting adjacent unit cells of the metasurface in parallel by a thin highly inductive wire and we demonstrate that this allows for the collection of current from all individual cells, while the microwave resonance of the unit cell is not significantly altered, thus solving the wiring problem that arises in many nonlinear metamaterials.
Mechanical dissipation in MoRe superconducting metal drums
Authors: Yanai S. , Singh V. , Yuan M. , Gely M. F. , Bosman S. J. , Steele G. A.
Published: February 2017

We experimentally investigate dissipation in mechanical resonators made of a disordered superconducting thin film of a Molybdenum-Rhenium(MoRe) alloy. Electrostatically driving the drum with a resonant AC voltage, we detect its motion using a superconducting microwave cavity. From the temperature dependence of mechanical resonance frequencies and quality factors, we find evidence for non-resonant, mechanically active two-level systems (TLSs) limiting its quality factor at low temperature. In addition, we observe a strong suppression of mechanical dissipation at large mechanical driving amplitudes, suggesting an unconventional saturation of the non-resonant TLSs. These observations shed light on the mechanism of mechanical damping in superconducting drums and routes towards understanding dissipation in such devices.
Impact of temperature-velocity distribution on fusion neutron peak shape
Authors: Munro D. H. , Field J. E. , Hatarik R. , Peterson J. L. , Hartouni E. P. , Spears B. K. , Kilkenny J. D.
Published: February 2017

Doppler broadening of the 14 MeV DT and 2.45 MeV DD fusion neutron lines has long been our best measure of temperature in a burning plasma. At the National Ignition Facility (NIF), yields are high enough and our neutron spectrometers accurate enough that we see finer details of the peak shape. For example, we can measure the shift of the peak due to the bulk motion of the plasma, and we see indications of non-thermal broadening, skew, and kurtosis of the peak caused by the variations of temperature and fluid velocity during burn. We can also distinguish spectral differences among several lines of sight. This paper will review the theory of fusion neutron line shape, show examples of non-Gaussian line shapes and directional variations in NIF data, and describe detailed spectral shapes we see in radiation-hydrodynamics simulations of implosions.
Magnetic stability of oxygen defects on the SiO2 surface
Authors: Adelstein Nicole , Lee Donghwa , DuBois Jonathan L. , Ray Keith G. , Varley Joel B. , Lordi Vincenzo
Published: February 2017

The magnetic stability of E′ centers and the peroxy radical on the surface of α-quartz is investigated with first-principles calculations to understand their role in magnetic flux noise in superconducting qubits (SQs) and superconducting quantum interference devices (SQUIDs) fabricated on amorphous silica substrates. Paramagnetic E′ centers are common in both stoichiometric and oxygen deficient silica and quartz, and we calculate that they are more common on the surface than the bulk. However, we find the surface defects are magnetically stable in their paramagnetic ground state and thus will not contribute to 1/f noise through fluctuation at millikelvin temperatures.
Partitioning of energy and nitrogen in lactating primiparous and multiparous Holstein–Friesian cows with divergent residual feed intake
Authors: Marett L. C. , Williams S. R. O. , Hayes B. J. , Pryce J. E. , Wales W. J.
Published: February 2017

Residual feed intake (RFI) is the difference between an animal’s actual and expected feed intake. Two experiments were conducted comparing energy and nitrogen partitioning in mid-lactation, in Holstein–Friesian cows selected for high or low RFI measured previously as growing calves. Each experiment used 16 cows (8 high-RFI and 8 low-RFI); the first used primiparous (PP) cows and the second used multiparous (MP) cows. Cows were housed individually for 4 days in metabolism stalls, then open-circuit respiration chambers for 3 days. Each cow was offered ad libitum lucerne hay cubes plus 6 kg DM per day of crushed wheat grain. Individual feed intake, milk yield, milk composition and faecal and urine output were measured. Methane and carbon dioxide output and oxygen consumption were measured in the chambers. In MP cows, a greater proportion of energy intake was partitioned to milk and less to heat in low-RFI than high-RFI cows. The proportion of gross-energy intake per kilogram metabolic bodyweight partitioned to milk production was greater and the proportion partitioned to methane and heat production was lower in MP than in PP cows. Energy from tissue mobilisation was not affected by RFI or parity. The amount of nitrogen consumed from feed was greater in MP than PP cows. As a percentage of N intake, N partitioned to milk was greater in PP than in MP cows, but there were no overall effects of RFI on N partitioning. However, there was a trend towards a positive association between N excreted in the urine and RFI, which could have environmental implications. Both RFI and parity were associated with variation in energy and nitrogen partitioning and should be examined in a larger subset of animals in future.