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The report of the 20th National Congress of the Communist Party of China pointed out that it is necessary to accelerate the construction of digital China, and actively develop equipment intelligence, digitalization, and high‐end equipment manufacturing. With the construction of a new round of digital China, the safety of digital technology and high‐end equipment is particularly important for power grid. Transformer is an important link of power grid operation. The destructive thermal failure of transformer has become a hot research issue in the power industry. At the same time, there are more and more power electronic equipment in the power grid, which makes the regulation and control more and more complicated. Taking a 1000 kVA oil‐immersed transformer as an example, the magnetic, current, and thermal multi field coupling numerical analysis method is first used to simulate and analyse the operation status of the transformer. By comparing the simulation results with the monitoring data results, the error of the results is controlled within 5%. Finally, the multi‐state characteristic parameters of the transformer are monitored through sensors, and the numerical simulation analysis results are integrated with the state monitoring results to build a transformer thermal life loss assessment system. The method in this paper can evaluate and analyse the running state of transformer in real time, which is of great significance for the power company to formulate the treatment measures. [ABSTRACT FROM AUTHOR]

Recently, a novel approach has been proposed to produce ultrashort, fully coherent high-repetition-rate EUVand X-ray radiation by combining an energy recovery linac (ERL) with the angular-dispersion-induced microbunching methodology. It is critical to maintain microbunching when the beam passes through bending magnets between the undulators, which results in difficulties supporting multiple beamlines. In this paper, the design of a multiplexed emitting system consisting of multi-bend achromats, matching sections and radiators to facilitate the multi-beamline operation is presented. Theoretical analysis and numerical simulations have been carried out and the results show that the microbunching and beam quality can be well maintained after four times of bending. Five radiation pulses with a central wavelength of 13.5 nm and peak power at theMW level have been produced by the same electron beam via this multiplexed emitting system. The proposed method holds potential in the multi-beamline operation of ERL- or storage-ring-based coherent light sources. [ABSTRACT FROM AUTHOR]

Bidirectional power flow is becoming increasingly commonplace in modern distribution systems with the integration Renewable Energy Sources (RESs) and Energy Storage Systems (ESSs). This has facilitated in bringing generation closer to end‐consumers, thus leading to the emergence and rapid growth of microgrids. Additionally, due to the technological revolution in Information and Communications Technology (ICT), innovative business models have developed where willing and able participants of the power system can participate in the electricity market. In line with this evolution of both the electric power system and its participants, Energy‐as‐a‐Service (EaaS) is emerging as an increasingly prominent business model to address electrical grid challenges economically. EaaS encourages electricity grid customers to play a more active role and participate in different electricity markets. This paper introduces and simulates a variant of a Transactive Energy (TE) trading algorithm for microgrids. The paper describes the model in brief how multiple microgrids assets can trade electricity to ensure more efficient and economical local resource utilization. The main motivations of this research paper is to validate and test the suitability of the TE trading algorithm for a variety of conditions. The coordinated TE trading model can optimize expansion and investment planning especially at the distribution level. [ABSTRACT FROM AUTHOR]

In the process of lower coal roadway support under double gobs in close coal seams, there are problems such as the whole destruction of the lower coal seam and the intermediate strata, the thin roof of the lower coal roadway with the smaller support space, the upper rock of the lower coal roadway without anchor bearing layer, the roof falling, the anchor cable offing, and so on. On the basis of the engineering background of No. 11103 haulage roadway in Fenxi coal mine, the research methods of theoretical modeling analysis, numerical simulation analysis and field engineering test are comprehensively adopted. In this paper, the layout of the roadway with floor insertion in the lower coal seam, the distribution characteristics of surrounding rock deviatoric stress, the control principle of broken surrounding rock and the coupling support method of shed–cable–prop are systematically studied. The study shows that many measures are needed to ensure the stability of the surrounding rock in the strong mining roadway of the lower coal seam. The lower coal seam roadway section was modified from the original rectangular section to adopt an arched section to counteract the broken roof. The staggered position of the lower coal seam roadway layout was modified from the original coal roadway position to a coal–rock roadway, so as to avoid the area of high deviatoric stress in the coal pillar and the area of crushed coal body, and to leave an effective support space for the roof. The support scheme of the lower coal seam roadway was improved to use anchor cable and single prop to support the weak section of U‐type steel shed with local coupling, and realize unequal force coupling by adjusting the size of the force at different coupling points. In the field monitoring the deformation of the roadway is small, and the support effect is good. [ABSTRACT FROM AUTHOR]

Conventional mooring systems contribute significantly to the cost of floating wind projects, and innovative solutions with cost‐saving potentials are desired. In the present paper, we investigate the fundamental dynamic behavior of an innovative tethered‐buoy mooring system for a prototype wind farm in which two spar floating offshore wind turbines (FOWTs) are moored to five submerged tethered buoys. Numerical decay tests are used to characterize the fundamental frequencies and oscillatory modes of the system. The influence of net buoyancy is established through a parametric study. Finally, the dynamic response of the tethered‐buoy mooring system is compared against two alternative shared mooring configurations with catenary mooring lines. Time‐domain simulations are carried out for one accidental scenario with a parked and an operational FOWT, and one extreme scenario with two parked FOWTs. The results show that net buoyancy has a significant influence on platform motions and mooring loads. Compared to alternative configurations with catenary mooring lines, the tethered‐buoy mooring system exhibits substantially lower mooring tension loads and practically eliminates the threat of snap events. The reduction in the maximum characteristic fairlead tension is up to 85%. The mean positional offset of the wind turbines in the loading direction is larger, up to 36% of the water depth, however, the relative motions are comparable. The mean distance between the FOWTs is even smaller for the tethered‐buoy system. With the application of dynamic inter‐array cables, the proposed tethered‐buoy system can be a promising mooring solution for floating offshore wind farms. [ABSTRACT FROM AUTHOR]

In this paper, we develop algorithms to independently draw from a family of conjugate posterior distributions over the structural parameterization when sign and zero restrictions are used to identify structural vector autoregressions (SVARs). We call this family of conjugate posteriors normal‐generalized‐normal. Our algorithms draw from a conjugate uniform‐normal‐inverse‐Wishart posterior over the orthogonal reduced‐form parameterization and transform the draws into the structural parameterization; this transformation induces a normal‐generalized‐normal posterior over the structural parameterization. The uniform‐normal‐inverse‐Wishart posterior over the orthogonal reduced‐form parameterization has been prominent after the work of Uhlig (2005). We use Beaudry, Nam, and Wang's (2011) work on the relevance of optimism shocks to show the dangers of using alternative approaches to implementing sign and zero restrictions to identify SVARs like the penalty function approach. In particular, we analytically show that the penalty function approach adds restrictions to the ones described in the identification scheme. [ABSTRACT FROM AUTHOR]

The evolution of Artificial Intelligence of Things (AIoT) pushes connectivity from human‐to‐things and things‐to‐things, to AI‐to‐things, has resulted in more complex physical networks and logical associations. This has driven the demand for Internet of Things (IoT) devices with powerful edge data processing capabilities, leading to exponential growth in device quantity and data generation. However, conventional data preprocessing methods, such as data compression and encoding, often require edge devices to allocate computational resources for decoding. Additionally, some lossy compression methods, like JPEG, may result in the loss of important information, which has negative impact on the AI training. To address these challenges, this paper proposes a two‐step attribute reduction approach, targeting devices and dimensions, to reduce the massive amount of data in the AIoT network while avoiding unnecessary utilization of edge device resources for decoding. The device‐oriented and dimension‐oriented attribute reductions identify important devices and dimensions, respectively, to mitigate the multimodal interference caused by the large‐scale devices in the AIoT network and the curse of dimensionality associated with high‐dimensional AIoT data. Numerical results and analysis show that this approach effectively eliminates redundant devices and numerous dimensions in the AIoT network while maintaining the basic data correlation. [ABSTRACT FROM AUTHOR]

Nowadays, fracture characterization of dissimilar materials adhesively bonded structures still generally refers to standards for fiber‐reinforced plastic composites. Moreover, the calculation methods of fracture energy release rate specified in these standards often lead to great deviation due to the differences in material properties and geometry. In this paper, dissimilar materials corrected beam theory with effective crack length (DM‐CBTE) method for calculation of mode II fracture energy release rate of dissimilar materials adhesively bonded structures was proposed. The differences in material properties and geometry as well as the effect of clamp were all considered. The experimental and J‐integral numerical analysis results showed that the maximum deviation of the GIIC calculated by the methods recommended in standard from the J‐integral result is 28% while that by the DM‐CBTE method is only 5%, which proved good feasibility of the DM‐CBTE method for evaluation of mode II fracture performance of dissimilar materials adhesively bonded structures. Highlights: DM‐CBTE method for GII of dissimilar materials adhesively bonded samples was proposed.The differences in material, geometry, and clamp correction were all considered.Good feasibility of the DM‐CBTE method for evaluation of GII was validated. [ABSTRACT FROM AUTHOR]

In this paper, attention is devoted to the analysis of the detection threshold based on the multi‐frame integration in heavy‐tailed clutter for the radar with high resolution and even smaller grazing angle. The closed‐form expressions of both the probability of the detection and the probability of false alarm for the heavy‐tailed clutter background, which can be used for the theoretical analysis of constant false alarm rate (CFAR) detectors, are derived with the multi‐frame integration technique. Accordingly, an improved CFAR detector is designed to work well with the presence of target‐like outliers in the heavy‐tailed clutter. In addition, the proposed CFAR detector is capable to alleviate the masking‐effect resorting to the additive feedback operation when a target is large enough to cross several cells in multi‐target case. The theoretical analysis and numerical simulations demonstrate that the proposed CFAR detector based on multi‐frame integration can improve the signal‐to‐clutter rate of the targets exhibiting better performance than ones based on single frame in heavy‐tailed clutter background. It is validated from the simulations that the proposed CFAR detector with additive feedback operation can deal with masking‐effect for large target occupying several cells. [ABSTRACT FROM AUTHOR]

It is difficult to separate Luer lock adapters during the external ventricular drainage (EVD) since they are often connected by a threaded connection, and the infusion needle put into the patient's body gets pulled out when extubation occurs unexpectedly. The paper described a new magnetic connection assembly made up of ring magnetic permanents and a Hall sensor that could be used to replace Luer lock adapters for quicker disconnection and reconnection of the drainage catheter. For the design and analysis of the device, the finite element method magnetics (FEMM) was used to estimate the size of magnetic permanents and the best detection site of the Hall sensor for detecting whether the magnetic permanents were closely attracted and/or pulled apart. Then an experiment was conducted to confirm our findings. Both simulation and experiment revealed that a pair of hollow cylindrical magnetic permanents, each with height 10 mm, outer diameter 8 mm, and inner diameter 4 mm, could achieve the same force as the Luer lock adapters held, and that the best Hall sensor detection position was in the middle of the permanent magnets, with a radial distance of about 2 mm. [ABSTRACT FROM AUTHOR]

The fiscal governance framework includes the rules and regulations that discipline the preparation, approval, and implementation of public budgets. It results from the power struggle of the actors that participate in the process of allocating public resources. Despite relevant studies published on the subject, this study aimed to provide background information on determinant factors in the choice and effects of fiscal governance framework adopted by governments in the scholarly conversation. For this, the systematic literature review method was adopted with the development of five steps: selecting a review topic, searching the literature, gathering, reading, and analyzing the scientific papers published in the last 10 years on the subject. Results show that fiscal crises and pressures and rewards of external bodies were the preponderant factors for reforms in the framework of fiscal governance adopted by governments. In another view, impacts of this framework on national public finances were investigated primarily by analysis of numerical fiscal rules. The research gaps identified indicate directions for future research. [ABSTRACT FROM AUTHOR]

Climate change will lead to prolonged droughts in various regions of the world, which may significantly affect agricultural production. This is particularly problematic for soils with low water retention capacity, which cannot store sufficient water for crops. In this paper, we investigate how a change in the water‐holding capacity of the soil material, as could be achieved by increasing the soil organic carbon (SOC) amount, affects the components of the soil water balance (evaporation, transpiration, and groundwater recharge). Specifically, we state the hypothesis that an increased water‐holding capacity in a shallow soil layer, as it is achieved through SOC enrichment at the soil surface, will result in more water being stored near the soil surface and lost to unproductive evaporation, thereby reducing the amount of water available to plants and groundwater recharge. The hypothesis was tested by numerical simulations, employing the Hydrus‐1D program package to model the water balance in a soil–plant–atmosphere system for an arable crop in hydrologically contrasting years. The study considered soils with varying textures and different depths of a soil layer with increased SOC content. The soil hydraulic properties (SHP) of the soil material, including the effect of SOC on the SHP, were determined using a recently developed pedotransfer model based on data from over 500 samples. We showed that both the improved water retention by SOC and its vertical distribution affect the soil water balance in a complex manner. In sandy soils, increasing the water‐holding capacity in shallow layers up to 0.1 m led to enhanced evaporation and thus a decrease in water availability for crops. However, deeper incorporated SOC could ameliorate these negative effects. Our findings suggest that not only the amount but also the vertical SOC distribution should be considered if enrichment of SOC shall be applied to mitigate the effect of droughts. Core Ideas: Addition of soil organic carbon (SOC) alters soil material's hydraulic properties.This, in turn, impacts the water balance of soils under agricultural use.The depth at which SOC is incorporated into soils plays a crucial role in the partitioning of evapotranspiration (ET) into evaporation (E) and transpiration (T).Deeper incorporation of SOC results in greater water availability for plants. [ABSTRACT FROM AUTHOR]

In this paper, the use of time‐varying piecewise quadratic functions is investigated to characterize the finite‐time stability of state‐dependent impulsive dynamical linear systems. Finite‐time stability defines the behavior of a dynamic system over a bounded time interval. More precisely, a system is said to be finite‐time stable if, given a set of initial conditions, its state vector does not exit a predefined domain for a certain finite interval of time. This paper presents new sufficient conditions for finite‐time stability based on time‐varying piecewise quadratic functions. These conditions can be reformulated as a set of Linear Matrix Inequalities that can be efficiently solved through convex optimization solvers. Different numerical analysis are included in order to prove that the presented conditions are able to improve the results presented so far in the literature. [ABSTRACT FROM AUTHOR]

This paper investigates a CFD‐based analysis for gas–liquid and liquid–liquid Taylor flows through a circular axisymmetric microchannel with a sudden enlargement. A series of simulations are conducted by exploring the influence of different superficial velocity ratios, apparent viscosities, and channel expansion on the hydrodynamics of slug flow. A concentric junction introduces dispersed airflow into a continuous flow of water for gas–liquid flow, and the junction introduces dispersed water into a continuous flow of dodecane for liquid–liquid flow. The air‐bubble and water‐slug evolution processes, slug breakup, and slug expansion are investigated. In all cases, the lengths of air bubbles and water slugs increase with increasing superficial velocity ratio, particularly before the expansion. For gas–liquid flow, the apparent viscosity ratio causes a fluctuating interface over the uniform film region. However, the water slug length is shorter and the film region is slightly thicker in liquid–liquid compared to gas–liquid flow. The numerical analysis developed in this paper is in good agreement with the existing correlations and experimental data in the literature. [ABSTRACT FROM AUTHOR]

The generated power of the Sea‐wave slot‐coned generator (SSG), as one of the high capacity wave energy converters, is dependent on the period and height of the waves. The generated power of this energy‐converter changes due to the variation in these parameters. Thus, different aspects of the power systems may be affected that must be investigated by increasing the share of these converters for electricity production in the power‐systems. In this paper reliability assessment of composite power‐systems containing large‐scale SSG is performed. The Xie and Beni (XB) index is calculated for obtaining the optimum number of states in the reliability model of the SSG and fuzzy c‐means clustering technique is proposed for reducing the number of states of the model. The contingency analysis method is proposed for calculating the reliability indices of the composite power‐system incorporating large‐scale SSG. DC load‐flow method, which considers line capacity, is used to perform load‐flow in the composite power‐system including generation and transmission networks. In the proposed technique, a load‐shedding program with the goal of minimizing the value of lost load is solved using of the linear programming method based on the interior‐point‐approach for contingency states leading to the load curtailment. [ABSTRACT FROM AUTHOR]

This paper deals with the integration and control of the doubly fed induction generator‐based wind turbine (DFIG‐WT) in a DC grid. In this way, the stator of the DFIG‐WT is integrated with the DC grid via an uncontrolled diode‐bridge rectifier as well as a buck converter to provide a flexible connection path. In addition, the rotor of the DFIG‐WT exchanges power with the DC grid through a rotor‐side converter (RSC). By considering the DFIG‐WT system topology, three control strategies based on the stator flux‐oriented vector control are developed for the RSC and buck converter. The control schemes consist of the outer and the inner control loops with the proportional–integral (PI) controllers. Additionally, the stability of control strategies and their dependence on the generator parameters are evaluated and compared using modal analysis and numerical simulations in the MATLAB/SIMULINK environment. Finally, a real‐time hardware‐in‐the‐loop emulation‐based OPAL‐RT 5600 is accomplished to assess the performance of the superior control method from a practical perspective. [ABSTRACT FROM AUTHOR]

Reinforced concrete frame‐bent structures are one of the structural forms commonly used in industrial factory buildings. In order to study the seismic behaviour of frame‐bent structures located near fault areas, eight pulse‐like, eight non‐pulse near‐fault motions and eight far‐fault ground motions have been selected in this paper. The finite element model of a reinforced concrete frame‐bent structure was established to study seismic responses to near‐fault and far‐field ground motions. Numerical analysis results indicate that the maximum base shear of the structure under the action of near‐fault ground motion was 5.10 times that of far‐fault and 1.47 times that of non‐pulsed near‐fault ground motion; the maximum story drift angle under pulse‐like near‐fault ground motion was 3.8 times that of non‐pulse and 19.7 times that of far‐fault ground motion. Therefore, engineering designers should pay more attention to the seismic performance of frame‐bent structures under the action of near‐fault ground vibration. [ABSTRACT FROM AUTHOR]

The air‐inflated rubber dam is innovatively adopted in this paper for temporary flood‐fighting at the subway entrance. Numerical studies using the FLAC2D software are carried out to investigate the behavior of the proposed structure. Laboratory model tests are also conducted to verify the accuracy of the numerical model. The results from the model tests agree well with those from the numerical analysis. Parametric studies are carried out to investigate the influences of the external floodwater head, inflated air pressure, and anchor position on the performance of the proposed air‐inflated rubber dam. It is found that the external floodwater head reduces the tensile force but nonlinearly increases the height of the rubber dam. The inflated air pressure has no obvious effect on the cross‐section of the rubber dam but heavily influences the ultimate flood‐fighting height and tensile force. An optimum design line for the inflated air pressure of the rubber dam is provided. A deeper anchor position results in a smaller ultimate flood‐fighting height. A rubber dam design with a lower anchor depth that has to satisfy the requirements of the anchor bolt is therefore concluded. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical behavior of 10 and 14 vol.% SiCp/Al composites was studied with both experiments and numerical analysis. A 3D macrostructure model based on modified Gurson–Tvergaard–Needleman (GTN) model was developed to predict the elasto‐plastic response and fracture behavior of particle reinforced aluminum matrix composites (PRAMCs). The particle size effects on the plastic strengthening induced by geometrically necessary dislocations (GNDs) were introduced, and the size distribution of the SiC particles was obtained according to the statistical analysis of the microstructure. The material parameters for GTN model were determined with a parameter identification process, and the validity of the numerical results was validated by the agreement of the experimental stress–strain curve. Results reveal that particle size randomness plays an important role in the fracture morphologies. Highlights: Establish a macro‐mechanical model to predict failure behavior of PRAMCs.Modify the GTN damage model to introduce the effect of particle failure and decohesion.Identify the parameters for the modified GTN model and validate the model by comparing with experimental results.Find that particle size randomness plays an important role in fracture morphologies. [ABSTRACT FROM AUTHOR]

This paper presents a new method of setting an upper bound for the aggregate error of an accounting population using Dollar Unit Sampling (DUS; see Anderson and Teitlebaum [1973]). The most widely used DUS bound setting procedure is the Stringer bound (Felix, Leslie, and Neter [1982]). This nonparametric procedure is popular because it produces a reliable bound for a wide variety of accounting populations. A disadvantage of the Stringer bound is that it is not statistically efficient, particularly when the population has low taintings. Other CAV (Combined Attributes and Variables) bounds have demonstrated the same problem (Reneau [1978]). A statistically inefficient bound may cause the auditor to conclude erroneously that the aggregate error may exceed a given material size, thereby promoting costly overauditing. The classical bound, an alternative distribution-free procedure that depends on the normality of the sampling distribution of the point estimator, is asymptotically efficient but unreliable in sample sizes used by auditors (Frost and Tamura [1986]). [ABSTRACT FROM AUTHOR]

The present paper is dedicated to the mechanical and fracture characterization of a specific earthen material, that is, the shot‐earth 772. Although such a material has been recently characterized from a microstructural, chemical and physical point of view, the knowledge of its mechanical and fracture properties (essential for extending its use in construction industry) is still lacking. Such characterizations are here performed both experimentally, through laboratory tests, and numerically, through a FE model. The experimental tests (i.e., flexural, compression, and fracture tests) are carried out on shot‐earth specimens according to recommendations available for concrete and a method proposed by the present authors, named Modified Two‐Parameter Model. The numerical analyses are performed by employing a micromechanical model (implemented in a nonlinear 2D FE homemade code), which allows to simulate both flexural and fracture behavior of the shot‐earth examined. Finally, the obtained numerical results are compared with the experimental ones. Highlights: The mechanical and fracture characterization of shot‐earth 772 is performed.Flexural, compression and fracture tests are carried out on the shot‐earth specimens.Numerical analyses are performed by using a homemade micromechanical finite element model.Flexural behavior and fracture behavior of shot‐earth 772 are numerically simulated. [ABSTRACT FROM AUTHOR]

Millimetre wave (mmWave) communications, that is, 30 to 300 GHz, have intermittent short‐range transmissions, so the use of reconfigurable intelligent surface (RIS) seems to be a promising solution to extend its coverage. However, optimizing phase shifts (PSs) of both mmWave base station (BS) and RIS to maximize the received spectral efficiency at the intended receiver seems challenging due to massive antenna elements usage. In this paper, an online learning approach is proposed to address this problem, where it is considered a two‐phase multi‐armed bandit (MAB) game. In the first phase, the PS vector of the mmWave BS is adjusted, and based on it, the PS vector of the RIS is calibrated in the second phase and vice versa over the time horizon. The minimax optimal stochastic strategy (MOSS) MAB algorithm is utilized to implement the proposed two‐phase MAB approach efficiently. Furthermore, to relax the problem of estimating the channel state information (CSI) of both mmWave BS and RIS, codebook‐based PSs are considered. Finally, numerical analysis confirms the superior performance of the proposed scheme against the optimal performance under different scenarios. [ABSTRACT FROM AUTHOR]

Due to the constraints of actual conditions, large‐scale research and analysis of micropumps are difficult to achieve. In this paper, the micropump is divided into a vibrating part and a flowing part through a similar theory research method, and the two parts of the mathematical model are simplified and dimensionless‐processed. Then, the similar relationship between the prototype machine and the model machine is proposed, the conversion relationship between the prototype machine and the model machine is obtained. In order to verify the correctness of the theoretical analysis, this paper uses ANSYS CFX analysis software to perform numerical analysis on a pair of prototype machines and model machines when the angle of diffusion and contraction is 30°. The size ratio of the prototype and model is 1/2. At the same time, experiments were used to verify the accuracy of numerical analysis by comparing the experimental value and the simulated value of the micropump outlet flow when the frequency is 100 Hz and the voltages are 25Vpp, 50Vpp, 75Vpp, 100Vpp, and 125Vpp. The results obtained by numerical simulation and experimental methods are consistent with theoretical analysis, thus verifying the accuracy of similar theories. The research results can provide the theoretical basis for the experimental research of the piezoelectric pump and also provide guidance for the design of the piezoelectric pump [ABSTRACT FROM AUTHOR]

This paper presents several methods for performing two types of static load model conversion: exponential to ZIP & ZIP to exponential model conversion. In general, these conversions are inaccurate due to non‐equivalence of exponential and ZIP (second‐order polynomial) models. A numerical analysis is conducted using generated datasets of load models to analyse the error and to compare the accuracy of the presented methods. The results of the analysis indicate that the optimal selection of conversion method depends on a number of factors, including normalisation of load models, ZIP model type (accurate or constrained) and expected use of the converted model. In addition, a case study is conducted to analyse the impact of conversion error on load flow results. The results of the case study indicate that a significant difference in load flow results can occur when the load models are converted. Recommendations for conversion method selection are given in the discussion section of the paper. [ABSTRACT FROM AUTHOR]

This paper proposes a new semi‐parametric identification and estimation approach to multinomial choice models in a panel data setting with individual fixed effects. Our approach is based on cyclic monotonicity, which is a defining convex‐analytic feature of the random utility framework underlying multinomial choice models. From the cyclic monotonicity property, we derive identifying inequalities without requiring any shape restrictions for the distribution of the random utility shocks. These inequalities point identify model parameters under straightforward assumptions on the covariates. We propose a consistent estimator based on these inequalities. [ABSTRACT FROM AUTHOR]

This paper presents a tri‐level stochastic coordinated transmission and distribution system expansion (CTDS) planning considering the deployment of energy hubs (EHs) across the distribution systems (DSs). The first level of the proposed optimization approach deals with transmission system expansion planning (TEP), while the second level develops distribution system expansion planning (DEP). Market clearing is done in the third level to update the locational marginal prices (LMPs) for different distribution system operators (DSOs). The EHs include photovoltaic cells (PVs), wind turbines (WTs), combined heating and power units (CHPs), boilers, and electrical and absorption chillers. The proposed tri‐level approach is solved with an iterative algorithm based on the diagonalization approach and tested on the modified IEEE 30‐bus transmission systems (TS) with several DSOs. Each DSO includes 18‐bus electrical, heating, and cooling energy systems. The numerical analysis shows that the total cost of the transmission system operator (TSO) is not changed with implementing the uncoordinated approach. However, the total cost of the whole system is reduced by 6.54% with accommodation of the EHs in the uncoordinated approach. Moreover, the total cost of the TSO as well as the whole system are reduced by 41.11% and 16.96%, respectively, with the proposed (CTDS) planning. [ABSTRACT FROM AUTHOR]

In this review paper, a critical assessment of the main degradation processes in three key components of solid oxide fuel cells and electrolysers (negative and positive electrodes and the interconnect) is undertaken, attempting prioritization of respective degradation effects and recommendation of the best approaches in their experimental ascertainment and numerical modeling. Besides different approaches to quantifying the degradation rate of an operating solid oxide cell (SOC), the latest advancements in microstructural representation (3D imaging and reconstruction) of SOC electrodes are reviewed, applied to the quantification of triple‐phase boundary (TPB) lengths and morphology evolution over time. The intrinsic degradation processes in the negative (fuel) electrode and the positive (oxygen) electrode are discussed, covering first the composition and governing mechanisms of the respective electrodes, followed by a comprehensive evaluation of the most important factors of degradation during operation. By this systematic identification of dominant degradation processes, measurement techniques, and modeling approaches, the foundations are laid for the definition of meaningful accelerated stress testing of SOC cells and stacks, which will help the technology achieve the constantly more demanding durability targets in market applications. [ABSTRACT FROM AUTHOR]

This paper studies the chatter stability of composite cutter bar milling system in rotating coordinate frame. The main contribution of this paper is establishing a continuous distributed chatter analysis model for a composite cutter bar milling system in rotating coordinate frame. The stability of the milling system with a rotary symmetric dynamic cutter bar is predicted using the semi‐discrete time domain method. The effects such as internal damping, external damping, and symmetrical and asymmetric laminates on the stability of the milling system were analysed, and the results were compared between rotating and fixed coordinate frames. The results are consistent for symmetrical cutter bars in both the rotating and fixed coordinate frames. A new chatter instability zone appears at high rotating speeds due to the material internal damping of the rotating composite cutter bar. [ABSTRACT FROM AUTHOR]

Autonomous vehicle technology based on information technology and software will lead the automotive industry in the near future. Vehicle localization technology is a core expertise geared toward developing autonomous vehicles and will provide location information for control and decision. This paper proposes an effective vision-based localization technology to be applied to autonomous vehicles. In particular, the proposed technology makes use of numerical maps that are widely used in the field of geographic information systems and that have already been built in advance. Optimum vehicle ego-motion estimation and road marking feature extraction techniques are adopted and then combined by an extended Kalman filter and particle filter to make up the localization technology. The implementation results of this paper show remarkable results; namely, an 18 ms mean processing time and 10 cm location error. In addition, autonomous driving and parking are successfully completed with an unmanned vehicle within a 300 mx 500 m space. [ABSTRACT FROM AUTHOR]

Obtaining the most Stimulated Reservoir Volume (SRV) by forming a complex fracture network is the prerequisite for shale gas hydraulic fracturing. In this paper, a coupled DFN–DEM model is presented based on a realistic discrete fracture network from fracturing treatment, to simulate the complex interactions between a created hydraulic fracture and a natural fracture system in shale. The sensitivity analysis of numerical simulation was performed to investigate the effects of hydraulic fracture length, multi‐fracture spacing, and internal friction angle on the stimulation reservoir area. The simulation results revealed that regardless of the DFN distribution and the length of hydraulic fracture, shear failure always tracked on the existing natural fracture plane. The amount and depth of the natural fracture shear into formation increased as the hydraulic fracture grew in length. Moreover, the actual dynamic morphology of fracture network was the radial or dendritic. A drastic change of permeability along the distance from injection may stimulate the fracture networks especially near the wellbore. For the multi‐fracture, the opening of the second fracture was able to stabilize the sheared fractures at the tip of the initial fracture. The shear failure area around the second fracture tended to increase with the growth of the length of the second fracture. Fracture network connectivity in the system is better for the optimal fracture spacing, and then fluid penetration during injection will influence the permeability evolution during stimulation. The stimulation reservoir area of the fracture network and the natural fracture friction angle had a quadratic relationship. Finally, the results by the data from field measurement in Sichuan, China verified that the proposed coupled DFN–DEM model had an accuracy up to 91.7%. The research results provide a reference for predicting the development of fracture network far away for multistage fracturing treatment. [ABSTRACT FROM AUTHOR]

Shale gas plays a crucial role in the national energy supply. However, fast pressure drop, production decline, and water resources pollution caused by well interference and fracture hits become more severe in multi‐layer mining shale gas fields. Such as, it is urgent to evaluate the interference of multi‐stage fracturing horizontal wells (MFHWs) between the upper and lower gas layers in Chinese Jiaoshiba shale gas field. Therefore, we put forward a comprehensive method to analyze the MFHW interference in this paper. The method contains bottom‐hole pressure response analysis (BHPRA) during neighboring well fracturing, BHPRA of well interference test, and production dynamic analysis. Our study indicates that longitudinal pressure interference exists between the Jiaoshiba upper and lower gas layers upon the apparent interference pressure response in a multi‐well test. However, MFHW interferences occur in the corresponding fracturing stages with shorter distance, and the interference strength is related to both well distance and fracturing scales. The Jiaoshiba upper gas layers can be developed to increase the gas production performance, but it is necessary to maintain a reasonable well spacing to avoid severe interference during the development. [ABSTRACT FROM AUTHOR]

In this paper, the problem of cooperative control of robotic sensor networks (RSNs) for monitoring dynamic pollutant plumes in two‐dimensional (2D) space is studied. The pollutant plume propagation dynamics is governed by a 2D advection‐diffusion partial differential equation (PDE), and the plume front is modelled by a level set with a pre‐specified threshold value. Distributed consensus Luenberger‐type PDE observers are first constructed using local concentration measurements from the RSNs for unanimous estimate of the dynamic concentration field over the entire spatial domain. With the aid of the distributed consensus observers, a leaderless cooperative control scheme is then developed for the RSNs to monitor the dynamic plume front expansion. It is proved using the Lyapunov stability method and set stability concept that the proposed cooperative control scheme guarantees tracking of the dynamic plume front expansion and coverage of the plume front. Extensive numerical simulation results demonstrate the effectiveness and merit of the proposed cooperative control scheme. [ABSTRACT FROM AUTHOR]

The purpose of operating a radar system multistatically is to acquire information about targets of interest more quickly and reliably than would be possible using disparate radars, which fuse data and track post‐detection. This paper identifies and addresses the critical issues for designing a coherent multistatic radar system using conventional coherent radars and proposes a set of design principles for configuring a coherent multistatic radar network with the aim of maximising the utility of information while constraining system cost and complexity. The issues discussed are as follows: the localisation of targets in three dimensions; eliminating the inevitable spatial ambiguities arising from sparse spatial sampling while exploiting the large aperture for high resolution; the achievement of spatial coherent processing gain for target detection; the effect of phase centre localisation, phase and frequency errors on synchronisation; the incorporation of three‐dimensional Doppler estimation for slow‐time coherent integration. The arguments presented are physically‐based and complemented by mathematical analysis and numerical experimentation using non‐linear sparse estimation, the sparse algorithm being critically important for resolving spatial ambiguities. An optimal configuration is identified, which has sufficiently many nodes to overcome spatial ambiguities and achieves significant spatial coherent processing gain, while simultaneously constraining the overheads of inter‐node synchronisation and communication. [ABSTRACT FROM AUTHOR]

This paper suggests a simple loading configuration for conducting the SCB (semi‐circular bend) tests on brittle materials to produce mixed mode I/III loadings. In the suggested test setup, the SCB specimen containing an inclined crack is loaded using a conventional three‐point bending fixture, but the bottom supports touches nearly half of the specimen thickness rather than the entire thickness. It is found that various mixed mode I/III loadings can be provided by rotating the crack, and especially the SCB specimen experiences pure mode III when the crack angle is set to be 90°. Different values of the crack length, span and crack angle are then considered in the numerical analyses to further study the proposed SCB test setup. Finally, several experiments are successfully conducted on the rock samples under various mixed mode I/III and pure mode III loadings to evaluate the SCB test setup in practical point of view. Research highlights: A simple loading configuration is suggested for conducting the SCB tests.Mixed mode I/III and pure mode III tests can be performed using the SCB specimen.Effects of crack length, span and crack angle in the SCB tests are numerically explored.Mode III has a negative effect on the fracture resistance of rock materials. [ABSTRACT FROM AUTHOR]

In this paper, the problem of opportunistic spectrum sharing for the next generation of wireless systems empowered by the cloud radio access network (C‐RAN) is studied. More precisely, low‐priority users employ cooperative spectrum sensing to detect a vacant portion of the spectrum that is not currently used by high‐priority users. The authors' aim is to maximize the overall throughput of the low‐priority users while guaranteeing the quality of service of the high‐priority users. This objective is attained by optimally adjusting spectrum sensing time, with respect to target probabilities of detection and false alarm, as well as dynamically allocating C‐RAN resources, that is, powers, sub‐carriers, remote radio heads, and base‐band units. To solve this problem, which is non‐convex and NP‐hard, a low‐complex iterative solution is proposed. Numerical results demonstrate the necessity of sensing time adjustment as well as effectiveness of the proposed solution. [ABSTRACT FROM AUTHOR]

This paper presents a refined full‐domain model for the fluidic‐thermal coupled analyses of a 15‐kW 30,000‐rpm high‐speed permanent magnet synchronous machine (HS‐PMSM) considering the heat generation and dissipation of the bearing components. In order to analyse the heat dissipation capacities of the bearing components, firstly, the fluid flow conditions inside the bearings with different revolution and rotation ratios are researched, and the most serious case is taken in the full‐domain calculations. Secondly, the three‐dimensional (3D) full‐domain model is established, and the fluidic‐thermal analyses are conducted based on the basic principles of numerical heat transfer and CFD. During calculations, in order to obtain the temperature rise precisely, the angular contact ball bearings are well modelled with all the internal components including the oil films, and the frictional loss in the bearings are computed by the Palmgren model. A 15‐kW 30,000‐rpm HS‐PMSM prototype is established and tested to verify the full domain thermal modelling methodologies and indirectly validate the bearing performance calculations. Finally, a self‐ventilated structure is employed to prevent the bearing temperature rise, and the cooling effectiveness is validated by numerical calculations. [ABSTRACT FROM AUTHOR]

In order to reveal the process of insulation destruction of circuit breaker in GIS under lightning impulse voltage, a new method of transient insulation numerical analysis is described in this paper. A combination of the electromagnetic transient analysis method and optimised charge simulation method (CSM) was put forward to calculate and analyse the transient insulation characteristics of 550 kV circuit breaker in GIS under lightning impulse voltage. The results show that, within 0–15 μ, though the voltage of circuit breaker did not reach its peak, there is severe electric field distortion caused by sharp change of voltage with a high probability of circuit breaker insulation breakdown. In addition, as for the circuit breaker insulation structure optimisation design, it is advisable to restrain the change rate of electric field strength amplitude so as to reduce the probability of insulation breakdown, rather than simply verify insulation structure by using maxi-mum electric field strength as the voltage input parameters of the electrostatic field under the power frequency in accordance with the traditional insulation analysis method, with the purpose of ensuring the circuit breaker can operate safely and reliably for a long time. [ABSTRACT FROM AUTHOR]

Many biological quantities cannot be measured directly but rather need to be estimated from models. Estimates from models are statistical objects with variance and, when derived simultaneously, covariance. It is well known that their variance–covariance (VC) matrix must be considered in subsequent analyses. Although it is always preferable to carry out the proposed analyses on the raw data themselves, a two‐step approach cannot always be avoided. This situation arises when the parameters of a multinomial must be regressed against a covariate. The Delta method is an appropriate and frequently recommended way of deriving variance approximations of transformed and correlated variables. Implementing the Delta method is not trivial, and there is a lack of a detailed information on the procedure in the literature for complex situations such as those involved in constraining the parameters of a multinomial distribution. This paper proposes a how‐to guide for calculating the correct VC matrices of dependant estimates involved in multinomial distributions and how to use them for testing the effects of covariates in post hoc analyses when the integration of these analyses directly into a model is not possible. For illustrative purpose, we focus on variables calculated in capture–recapture models, but the same procedure can be applied to all analyses dealing with correlated estimates with multinomial distribution and their variances and covariances. This paper proposes a how‐to guide about how to calculate the correct VC matrices of dependant estimates involved in multinomial distributions and how to use them for testing the effects of covariates in post hoc analyses when the integration of these analyses directly into a model is not possible. [ABSTRACT FROM AUTHOR]

This paper considers equilibrium quit turnover in a frictional labor market with costly hiring by firms, where large firms employ many workers and face both aggregate and firm specific productivity shocks. There is exogenous firm turnover as new (small) startups enter the market over time, while some existing firms fail and exit. Individual firm growth rates are disperse and evolve stochastically. The paper highlights how dynamic monopsony, where firms trade off lower wages against higher (endogenous) employee quit rates, yields excessive job-to-job quits. Such quits directly crowd out the reemployment prospects of the unemployed. With finite firm productivity states, stochastic equilibrium is fully tractable and can be computed using standard numerical techniques. [ABSTRACT FROM AUTHOR]

Inclusion is one of the main causes for unqualified wire. However, the forming mechanism of drawing fracture due to inclusions is still unclear. Therefore, it is significant to figure out the forming mechanism of wire drawing fracture with inclusions for designing and manufacturing high‐quality wires. In this paper, a physical model of wire with inclusion is established based on experimental observations. Multipass drawing is simulated by using finite element method (FEM) with the developed numerical damage modeling. Numerical results demonstrate that the damage increases with the development of drawing progress, and the damage caused by high elastic modulus of inclusion is greater than that of low elastic modulus. Pen‐tip shaped fracture of wire with inclusions is mainly caused by the superposition of core and external V‐shaped damage. Furthermore, the core V‐shaped crack will propagate along the external V‐shaped damage area. [ABSTRACT FROM AUTHOR]

This paper deals with optimal power allocation for channel estimation of orthogonal frequency-division multiplexing uplinks in time-varying channels. In the existing literature, the estimation of time-varying channel response in an uplink environment can be accomplished by estimating the corresponding channel parameters. Accordingly, the optimal power allocation studied in the literature has been in terms of minimizing the mean square error of the channel estimation. However, the final goal for channel estimation is to enable the application of coherent detection, which usually means high spectral efficiency. Therefore, it is more meaningful to optimize the power allocation in terms of capacity. In this paper, we investigate capacity with imperfect channel estimation. By exploiting the derived capacity expression, an optimal power allocation strategy is developed. With this developed power allocation strategy, improved performance can be observed, as demonstrated by the numerical results [ABSTRACT FROM AUTHOR]

This paper develops a simple model of firm entry, competition, and exit in oligopolistic markets. It features toughness of competition, sunk entry costs, and market‐level demand and cost shocks, but assumes that firms' expected payoffs are identical when entry and survival decisions are made. We prove that this model has an essentially unique symmetric Markov‐perfect equilibrium, and we provide an algorithm for its computation. Because this algorithm only requires finding the fixed points of a finite sequence of contraction mappings, it is guaranteed to converge quickly. [ABSTRACT FROM AUTHOR]

Non‐orthogonal multiple access (NOMA) has attracted great attention due to its potential of providing high spectral efficiency and massive connectivity. Combining it with multiple‐input multiple‐output (MIMO) technology can further improve the spectrum efficiency. In this paper, the power allocation problem in downlink multi‐cluster MIMO‐NOMA systems is investigated for maximizing the fairness utility function. First, a long‐term fairness function is considered and the optimization problem is formulated as a weighted sum‐rate maximization problem. The problem is transformed into a convex form by introducing two sets of auxiliary variables, and propose an iterative algorithm to update the weight factors and the auxiliary variables. Then, an instantaneous fairness is considered and the optimization problem is formulated as a minimum data‐rate maximization problem. It is transfiormed into a one‐dimensional optimization problem based on an iterative algorithm and a closed‐form power allocation expression is deduced. Simulation results illustrate that the proposed two fairness power allocation schemes have better performance of edge‐user rate than the comparable schemes. [ABSTRACT FROM AUTHOR]

Laplace transforms are frequently used in the design of control structures for chemical engineering processes. In this paper, we have developed a novel numerical method to invert Laplace transforms, which involves a particular system of linear algebraic equations. We have proven that the error of our method is bounded, and the proposed formula asymptotically converges to the exact intended Laplace inverse function. A set of numerical simulations have been carried out to demonstrate the efficiency and reliability of our method. As a salient advantage, in addition to its high accuracy, our method requires the Laplace transform function to be defined only on the real axis. [ABSTRACT FROM AUTHOR]

The paper concerns an experimental study on the crack deflection angle in a semi‐circular disc made of an alkali‐activated fine‐grained composite under mixed‐mode conditions. This study is supplemented by an extensive numerical analysis that calculates the crack deflection angles via generalized (multi‐parameter) fracture criteria. It is proved that the use of higher‐order terms of the Williams expansion for the approximation of the crack‐tip stress field leads to more accurate results. The influence of various parameters on the crack deflection angle is discussed, and recommendations on their proper choice are presented. The conclusions help in describing the crack behaviour under mixed‐mode conditions more accurately. [ABSTRACT FROM AUTHOR]

This paper studies energy-efficiency (EE) power allocation for cognitive radio MIMO-OFDM systems. Our aim is to minimize energy efficiency, measured by "Joule per bit" metric, while maintaining the minimal rate requirement of a secondary user under a total power constraint and mutual interference power constraints. However, since the formulated EE problem in this paper is non-convex, it is difficult to solve directly in general. To make it solvable, firstly we transform the original problem into an equivalent convex optimization problem via fractional programming. Then, the equivalent convex optimization problem is solved by a sequential quadratic programming algorithm. Finally, a new iterative energyefficiency power allocation algorithm is presented. Numerical results show that the proposed method can obtain better EE performance than the maximizing capacity algorithm. [ABSTRACT FROM AUTHOR]

As far as outbursts activity is concerned, the 29P/Schwassmann-Wachmann 1 is the exceptional comet. This Centaur object shows quasi-regular flares with periodicities of 50 days (Trigo-Rodriguez et al. 2010). In the introductory part of the presented paper the most well-known hypotheses which try to explain this cometary behaviour are reviewed. The second, actual part of this paper presents the new model for the outburst activity of this comet. The model is based on the idea of Ipatov (2012), according to which there are large cavities below a considerable fraction of the comet's surface containing material under high gas pressure. In favourite conditions the surface layers over the cavities are thrown away and the interior of these cavities is exposed. Consequently, an outburst of the comet's brightness may be observed. The main characteristics of an outburst of this comet, the brightness jump, is calculated. Numerical simulations were carried out for wide range of possible cometary parameters. The obtained results are in good agreement with the observations. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Polymeric foams have good capacity of absorbing energy in compression but are brittle in tension. Linear elastic fracture mechanics is successfully applied to assess the integrity of polymeric foam‐based composite structures. The fracture toughness represents an important parameter. The different approaches to estimate the fracture toughness of polymeric foams are reviewed: analytical and numerical micromechanical models and experimental investigations. Focus is given on the parameters influencing the fracture toughness of polymeric foams like specimen type, solid material, density, loading speed, size effect and temperature. Data on mixed‐mode loading and dynamic fracture toughness are also presented. The last part of the paper presents some results to increase the fracture toughness by reinforcing of polymeric foams. [ABSTRACT FROM AUTHOR]

The aim of the security and stability control system (SSCS) is to maintain active power balance and frequency stability. For large SSCS, it is difficult to find the state space and the transition rates of the paths. The flat design yields more complex topology. Considering the random outages, the ultra‐high‐voltage dc (UHVDC) has more capacity levels and states. The existing evaluation cannot quantify the power balance capability of the SSCS. This paper newly quantifies active power balance capability of the multi‐level SSCS with partial or complete outage of the UHVDC. An incidence matrix is proposed to describe the topology of the SSCS. A recursive solution to calculate the transition rates is proposed. The equivalent downward transition rate is newly defined. The increasable generation and the transition rates of the UHVDC at any initial state are newly included. The numerical analysis shows that the incidence matrix and recursive algorithm reduces the calculation effort for the practical SSCS with multi‐level, redundancy component, and flat design. The active power balance capability of the SSCS is decided by the increasable power, the reduced generation and the downward transition rate. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper deals with the rectangular tensile sheet with symmetric double edge notch cracks. Such a crack problem is called an edge notch crack problem for short. By using a hybrid displacement discontinuity method (a boundary element method), two edge notch models are analyzed in detail. By changing the geometrical forms and parameters of the edge notch, and by comparing the stress intensity factors (SIFs) of the edge notch crack problem with those of the double edge cracked plate tension specimen (DECT), which is a model frequently used in fracture mechanics, the effect of the geometrical forms and parameters of the edge notch on the SIFs of the DECT specimen, is revealed. Some geometric characterestic parameters are introduced here, which are used to formulate the notch length and the branch crack length, which are to be determined in mechanical machining of the DECT specimen So we can say that the geometric characterestic parameters and the formulae used to determine the notch length and the branch crack length presented in this paper perhaps have some guidance role for mechanical machining of the DECT specimen. [ABSTRACT FROM AUTHOR]