Adjustment Coefficient Research Articles

A dynamic bidding strategy of hybrid energy storage system participating in day-ahead frequency regulation market

The rapid proliferation of intermittent and unpredictable renewable resources poses an unprecedented challenge to frequency stability in the modern system. A hybrid energy storage system (HESS) typically comprised of battery and ultracapacitor has better performance in quick response. In this context, this paper elaborates on a dynamic bidding strategy for an independent HESS operator to provide frequency regulation service in a day-ahead performance-based market. The proposed framework aims to maximize the net profit of the HESS operator based upon a two-part settlement mechanism considering the HESS degradation. Furthermore, the separated optimization of the battery and ultracapacitor can be realized by introducing a VSQF frequency division algorithm to leverage the full advantage of the HESS. Also, the optimization process in each stage can be innovatively driven by an improved snake optimizer and a penalty function is utilized to fulfilling the HESS-related and market-related constraints. The comparison between the HESS and the battery energy storage system (BESS) shows that HESS has indeed economic superiority and yields an 18.59 % higher profit. Moreover, the economic benefits under conservative SoC management by the flexible adjustment of the penalty coefficient are 9.06 % higher than that with the strict terminal SoC constraint which verifies the effectiveness of the dynamic bidding.

Performance-based assistance control for robot-mediated upper-limbs rehabilitation

Clinical research results demonstrated that robot-mediated training for the recovery of subjects after the stroke had the benefit of being able to carry out high-intensity repetitive and task-oriented tasks, which could effectively facilitate the rehabilitation effect. However, these subjects may have different training requirements as the disability levels vary from subject to subject at different stages of rehabilitation. Therefore, to meet the rehabilitation training needs of subjects in different rehabilitation stages, a performance-based assistance control strategy for safe robot-mediated therapy is proposed in this paper. The strategy contains three training modes that are switched by the trajectory tracking error, the zero interaction force mode (ZIF), assist-as-needed (AAN) mode, and restriction interaction region (RIR) mode. In ZIF mode, the subject can freely refer to their motion trajectory, and the robot will only offer fixed assistance only when the subject is slacking. In AAN mode, the robot would offer a variable level of assistance force by adjusting the stiffness coefficient to assist subjects in accordance with their motor abilities. To assure safety, a sizable assisting force is applied in RIR mode. To validate and evaluate the effectiveness and performance of the proposed assistance control strategy, a set of task-oriented continuous movement experiments based on an end-effector robot-mediated training system were performed by five able-bodied subjects. The preliminary experiment results demonstrated that the proposed control strategy works properly and could provide corresponding assistance and adjust the working modes according to the subject's motor performance. It was found that the robot provided more assistance as the increasing trajectory tracking error led to a decrease in motor performance. Additionally, adaptive adjustment of the stiffness coefficient allowed the proposed assistance control strategy to induce more active effort. It's worth noting that the parameters of the proposed strategy may be personalized and adjusted for different subjects to satisfy various requirements.

Spatiotemporal differentiation and the coupling analysis of ecosystem service value with land use change in Hubei Province, China

Rapid urbanization has exacerbated land use transformation, which in turn has affected ecosystem service value (ESV). Clarifying the spatial association between land use change (LUC) and ESV is of relevance to the development of policies for sustainable land development and ecosystem service (ES) management. In this paper, taking Hubei Province as an example, the biomass coefficient, resource scarcity coefficient and socioeconomic adjustment coefficient are introduced to improve the ESV assessment model, and then the spatiotemporal dynamics of land use and ESV from 2000 to 2020 are analyzed. Furthermore, the coupling coordination degree (CCD) between land use intensity and ESV was explored through a CCD model. The results show that (1) land use in Hubei Province changed significantly from 2000 to 2020, mainly in cropland and built-up land. (2) The change in ESV showed a fluctuating upward trend, with an increase of 71.30%, and the spatial differences generally decreased, showing a spatial pattern of “low in the center and high in the surroundings”. (3) All individual ESVs first decreased and then increased, with regulating services and supporting services contributing more to ESV and hydrological regulation, maintenance of biodiversity and soil conservation being the top three ecosystem functions with high service value. (4) The CCD between ESV and land use intensity in Hubei Province and its cities (prefecture and forest area) decreased and then increased, being at the lowest and highest values in 2005 and 2020, respectively. This paper revealed the spatiotemporal evolution process of LUC and ESV in Hubei Province and their coupling coordinated relationship, which can provide effective guidance for the formulation of interzonal ES maintenance policies to reconcile the conflicts between land use and ecosystem management.

Characteristics of Strong Ground Motions from Four M S ≥ 5.0 Earthquakes in the 2021 Yangbi, Southwest China, Seismic Sequence

ABSTRACT A seismic sequence has struck the Yangbi county, west part of Yunnan Province in southwest China since May 18, 2021 . This region experienced the strongest ground shakings on the night of 21 May with the successive occurrence of four earthquakes with M S ≥5.0 in a short time and more small earthquakes. Large numbers of strong-motion recordings obtained in the four earthquakes with M S ≥5.0 (i.e. the M S 5.6 foreshock, the M S 6.4 mainshock, the M S 5.0 and M S 5.2 aftershocks) were analyzed in detail to characterize the source effects, distance decay, etc. The velocity pulse-like waveform at near-source station 53YBX and the significant asymmetry of distance decay along the SSE-NNW direction (i.e. much slower toward the SSE) in the M S 6.4 mainshock seem to hint the occurrence of the asymmetrical source rupture. The source rupture directivity for the four events were investigated by fitting the azimuth-dependent residuals of the PGAs. The M S 6.4 mainshock is characterized by the significantly asymmetrical bilateral rupture propagation, predominantly in the SSE direction with a rupture velocity of about 2.24 km/s. The PGA and PSAs from the four earthquakes were further compared with the predicted medians of the ASK14 and CY14 prediction models for global shallow crustal earthquakes. The negative inter-events residuals reflect the weaker source contributions of the Yangbi events to ground motions. The source contributions to short-period ground motions approximately show the dependence on earthquake type, that is, M S 5.6 foreshock > M S 6.4 mainshock > M S 5.2 aftershock, consistent with the dependence of stress drop on earthquake type. We further noted that the inter-events values for the M S 5.0 aftershock are far below those for the M S 5.2 aftershock. This may be attributed to the differences in the spatial and temporal distance to the mainshock, that is, weak source contributions from the close aftershocks to the mainshock. The values of adjustment coefficient Δc 3 are almost positive, indicating the weaker anelastic attenuations in the study region. Finally, we also found that the distance scaling of significant duration can be well described by both empirical models (AS16 model for predicting significant duration and the BT14 model for empirically illustrating the ground-motion path duration).

Nanowires for UV–vis–IR Optoelectronic Synaptic Devices

AbstractSimulating biological synaptic functionalities through artificial synaptic devices opens up an innovative way to overcome the von Neumann bottleneck at the device level. Artificial optoelectronic synapses provide a non‐contact method to operate the devices and overcome the shortcomings of electrical synaptic devices. With the advantages of high photoelectric conversion efficiency, adjustable light absorption coefficient, and broad spectral range, nanowires (NWs)‐based optoelectronic synapses have attracted wide attention. Herein, to better promote the applications of nanowires‐based optoelectronic synapses for future neuromorphic systems, the functionalities of optoelectronic synaptic devices and the current progress of NWs optoelectronic synaptic devices in UV–vis–IR spectral range are introduced. Furthermore, a bridge between NWs‐based optoelectronic synaptic device and the neuromorphic system is established. Challenges for the forthcoming development of NWs optoelectronic synapses are also discussed. This review may offer a vision into the design and neuromorphic applications of NWs‐based optoelectronic synaptic devices.

LINGKUNGAN KERJA, BUDAYA ORGANISASI, DISIPLIN KERJA DAN KINERJA KARYAWAN

The purpose of this study was to determine how the influence of the work environment, organizational culture, and work discipline on employee performance at PT Cartini Lingerie Indonesia unit 2 Klaten. The research population consisted of 289 people was taken using a random sampling technique of 163 people. Multiple linear regression was used in this study to manage SPSS version 25 data. The study findings show that the work environment, corporate culture, and work discipline all have an impact on employee performance, either separately or together at PT Cartini Lingerie Indonesia Unit 2 in Klaten. The results of the R adjustment coefficient is 78% indicate that the work environment, organizational culture, and work discipline have an effect on employee performance, while the remaining 22% is influenced by other factors not examined such as motivation, work placement leadership, and others.

A generalized objective function based on weight coefficient for topology-finding of tensegrity structures

This paper proposes a generalized objective function for the topology-finding of tensegrity structures to be able to assign selection priorities to different members and efficiently find multiple tensegrity structures through a single ground structure. The generalized objective function is constructed by the sum of the product of member internal forces and weight coefficients. The member weight coefficients can be defined and adjusted freely to change the selection priorities of different members in the topology-finding process. By adjusting the weight coefficients, different tensegrity structures can be generated. The weight coefficients can be determined by the designer according to the practical design requirements and preferences, e.g., member length limitations, member position requirements. In addition, a circular computing strategy is proposed for the weight coefficient adjustment to efficiently obtain a large number of tensegrity structures through a single ground structure. The topology design of typical regular tensegrity structures, as well as irregular ellipsoid tensegrity structures, are carried out to demonstrate the effectiveness of the proposed method. Furthermore, by using the proposed method, multiple novel tensegrity structures based on common Archimedes polyhedrons have been found; detailed information (e.g., member connectives, self-stress) are given as an open database for future investigation and applications.

MANAGEMENT OF PUBLIC INVESTMENTS BY USING THE ACCELERATOR MODEL

In this study, the development of public investment and exchange in Turkey tested. Between 1990 and 2014, "Evoked Multiplier", "Accelerating" model was used in evaluating the effects of public investments on the development of the industry and the development of industrial production. The SPO and Undersecretariat of Treasury's current account have been stabilized with the GDP deflator. First, the theoretical structure of stimulated multiplier investment model is emphasized. The solutions are logarithmic and exponential. The general principle of the study is that the level of production is also effective on the investment at the desired time, and the investments made in the previous periods will also be effective for the future. The fact that each level of production is defined by capital and that the exact amounts of investments are determined becomes important for future plans at macro level. Making profitable for production is about investments. Determination of the multiplier, depreciation rate and adjustment coefficients for decision makers is becoming important.

Laterally-excited bulk acoustic wave resonator with an adjustable piezoelectric coupling coefficient

This paper reports on a design journey for a laterally-excited bulk acoustic wave resonator (XBAR) with an adjustable piezoelectric coupling coefficient (K 2). The vibration principle and resonant characteristics of XBAR are investigated by theoretical and simulation analysis, and the way to adjust K 2 by introducing two grooves in the area between interdigital electrodes (IDEs) is proved to be effective by using the finite-element method (FEM) simulation and the Modified Butterworth–Van Dyke model with series capacitor C r (MBVD-C r ) first, and then the impact of groove depth (H g) and groove width (W g) on K 2 of XBAR is theoretically analyzed. Specifically, K 2 can be effectively adjusted by setting different values of H g and W g. After optimization, the maximum regulation range of K 2 is from 2.02% to 45.05%. The fluted XBAR has remarkable potential in building an XBAR bandpass filter for specific frequency bands, which greatly optimizes the XBAR filter design.

Predictive cruise control for 4WD electric vehicle based on dynamic weight factors

By computing the velocity trajectory based on the advancing road and traffic information, the predictive cruise control (PCC) system can significantly reduce vehicle energy consumption. As the weight factors of different objective item have an important influence on the control results of PCC system, this paper proposed a novel optimization method with dynamic weight factors according to the classification of road slope for 4 wheel drive intelligent (4WD) electric vehicles. In order to determine the weight coefficient adjustment method, the influence of road slope on the PCC performance was analyzed and a road category identification method was presented. The results of simulation indicated that the proposed PCC based on dynamic weight coefficients can improve the adaptability of PCC on different categories of road. Compared with the traditional PCC with constant weight coefficient, the maximum energy-saving rate can reach 32.3% at a small cost of driving distance 3.86% on rapid downhill road. For other type of road, uphill and continuously undulating road, the energy-saving rate was low, where it was more important to improve the driving efficiency by 1.46%.

Complexity analysis and control of game behavior of subjects in green building materials supply chain considering technology subsidies

The national priority of carbon neutrality and decarbonization goals drive the transformation and upgrading of China’s construction industry. The production of green building materials is one of the key ways to decrease carbon emission. To better promote the green development of the construction industry and the realization of the decarbonization goals, a supply-chain system under technology subsidies, inclusive of a general contractor, two green building material manufacturers, is investigated. The Stackelberg model of green building material supply chain is constructed to explore how the green technology innovation of supply chain main body is affected by the technology subsidy. Meanwhile, the backward induction method is utilized to analyze the technology innovation decision-making behavior of green building material players of supply chain under a dynamic game. MATLAB software is used to simulate the stability and dynamic changes of the system in the long-term game. The results show that the decision-making stability of green building material supply chain is beneficial to the stability of supply chain system. The technology subsidy standard with reasonable policy promotes the degree of green building materials to achieve the maximum. However, once the adjustment coefficient of decision-making variables of the main body of the supply chain is large, the supply chain system will fall into chaos and disorder through bifurcation. The delayed feedback control method thus needs to be applied to control chaos, to ensure the sustainable and healthy development of the supply chain of green building materials. This study expands the application scenario of complex system theory in construction supply chain. It also provides theoretical guides for the government to formulate policies to encourage the promotion of green building materials.

A Low Complexity Two-Stage LLR Detector for Downlink OFDM-IM NOMA

OFDM-IM based Non-Orthogonal Multiple Access is a recently developed scheme, where flexibility is provided by both NOMA and OFDM-IM with an adjustable power allocation coefficient and an adjustable subcarrier activation ratio, respectively. However, the computational complexity of the Maximum Likelihood (ML) detector, used in the OFDM-IM NOMA scheme is very high. In this letter, a low complexity “two-stage Log-Likelihood Ratio (LLR)” detector is proposed for the OFDM-IM NOMA scheme. Computer simulation results and complexity analysis verify that the proposed detector performs almost the same as the ML-based detector in all the various conditions, with much reduced computational complexity.

Effects of multiple cropping of farmland on the welfare level of farmers: Based on the perspective of poverty vulnerability

This paper aims to explore the impact of multiple cropping on farmers’ welfare level and provide the theoretical and empirical basis for solving relative poverty in rural areas in the future. The paper uses data from the field survey of 1,120 farmers in Hubei in 2018 and uses the Endogenous Transformation Regression Model (ESR) and generalized propensity score matching (GPSM) model to construct a counterfactual framework. The paper analyses the effect of multiple cropping on farmers’ relative poverty and examines its mechanism. The result shows that: Multiple cropping of farmland can reduce the relative poverty of farmers through the mechanism of yield improvement path and factor intensification path. Under the counterfactual hypothesis, the relative poverty of farmers would increase by 28.43% if the farmers who participated in the multiple cropping did not; and that the relative poverty of the farmers would decrease by 29.57% if the farmers who did not participate in the multiple cropping participated. From the perspective of multiple cropping, the poverty reduction effect of multiple cropping in paddy fields is higher than that of dry land. From the perspective of the degree of multiple cropping, the poverty reduction effects of paddy fields and dryland will experience an increasing return to scale as the multiple cropping index increases. When the household equivalent scale adjustment coefficient is not used to eliminate the impact of family population structure on the “family per capita comparable income,” the artificially high results estimated by the model cannot truly reflect the poverty-reducing effect of multi-cropping of farmland. This paper argues that the government can guide farmers to choose the suitable mode of multiple cropping to reduce farmers’ vulnerability to relative poverty.

Construction and application of prediction methods for coal texture of CBM reservoirs at the block scale

Identifying coal texture has an important influence on the exploration and development of coalbed methane (CBM), but the prediction at the block scale is still insufficient. This paper combines the core idea of machine learning algorithm, coal body deformation mechanism, and critical layer theory to establish a prediction method for coal texture of CBM reservoir at block scale. The factor analysis method was used to eliminate the information redundancy of logging data, and the key logging parameters for identifying the coal texture were optimized. These include density (DEN), natural gamma ray (GR), X well diameter (CALX), and deep lateral resistivity (LLD). The K-means clustering algorithm was used to extract the numerical characteristics of crucial parameters. The K-nearest neighbor (KNN) classification algorithm established the identification equation of coal texture. The following classification was obtained: primary structural coal (T ≥ 0.70), broken-mylonite coal (T ≤ −0.50), and cataclastic coal (−0.50 < T < 0.70); these were used to accurately and finely divide the coal texture of multiple coal seams. Subsequently, from the fact that the structure of the coal body of a coal seam is necessarily influenced by the critical layers of the coal-bearing rock system in which it is located, the value of S for the strength of the coal-bearing rock system is proposed. According to the deformation characteristics of the coal body and the critical layer theory of the coal reservoir in the mining area, the length of the coal-bearing rock system section is determined as 30 m for the top plate and 20 m for the bottom plate of the coal seam and combined with the strength adjustment coefficient. The S value calculation is derived. The S value was calibrated using the calculation results of the coal texture logging identification model: primary structural coal (S ≥ 4.50), cataclastic coal (3.50 < S < 4.50), and broken-mylonite coal (S ≤ 3.5). Finally, the above methods are used to identify the block scale coal texture of the main coal seam of Kele syncline in western Guizhou. The identification prediction results are the same as those of underground sampling.

Physics-Based Simulation of Soft-Body Deformation Using RGB-D Data.

Providing real-time interaction in an immersive environment has drawn considerable attention in the virtual training fields. Physics-based simulations are suitable for such environments; however, they require the definition and adjustment of coefficients that determine material properties, making the methods more complex and time-consuming. In this paper, we introduce a novel approach to simulating the soft-body deformation of an observed object. Using an off-the-shelf RGB-D sensor, the proposed approach tracks an object’s movement and simulates its deformation in an iterative manner. Polygonal models with different resolutions are used to improve the simulation speed and visual quality. During the simulation process, a low-resolution model is used for surface deformation using neighboring feature points detected from the sensor, and a volumetric model is added for internal force estimation. To visualize the observed model in detail, the deformed and low-resolution model is mapped to a high-resolution model using mean value coordinate interpolation. To handle topological deformations, such as cutting or tearing, a part intersected by a cutting tool is recognized by the sensor and responds to external forces. As shown in the experimental results, our approach generates convincing deformations of observed objects in real time.

Credit risk cyclicality in Serbian banking sector

ABSTRACT In literature there are different research results regarding the impact of borrower’s size on cyclicality of credit risk. The aim of this research is to determine whether the credit risk cyclicality increases with the size of the borrower, using data from Serbian banking sector. The research presented herein is one of the first for developing countries with this subject and where credit risk was approximated by the default rate. Empirical analysis of the time series of loan default rates, as dependent variable, and macroeconomic factors, as explanatory variable, is based on the panel error correction model. Panel units are risk segments. Amount of annual revenue is key criteria for granulation borrowers within key four risk segments (retail, micro, SME and large corporate) that corresponds to its size. In multi-factor model, research results confirm that there is long term relationship between macroeconomic factors and loan default rate in Serbian banking sector in all risk segments. However, in model where GDP is explanatory variable, in the segment of small- and medium-sized enterprises, the adjustment coefficient is not statistically significant. It can be inferred that the credit risk of the SMEs segment is the most resistant to changes in the business cycle phases.

The Taylor Rule in Egypt: Is it Optimal? Is there Equilibrium Determinacy?

We investigate Egypt's Taylor rule (interest rate targeting) between 1976 and 2019 by including the main economic variables in its reaction function. Using the Taylor principle, we investigate Egypt’s monetary policy optimality. To this end, we conduct the generalized method of moments (GMM) estimation procedure with different Taylor rule specifications to deal with potential endogeneity among variables. Our GMM estimates reveal that the partial adjustment coefficient is of considerable magnitude, indicating the explanatory power of policy inertia on many total variations in the current values of the nominal interest rate in Egypt. Furthermore, the inflation gap coefficient violates the Taylor principle, making the policy procyclical and inflation "spiral" and inducing divergence from the long-run equilibrium. Therefore, Egypt's Taylor rule, and thus monetary policy, reflects the indeterminacy of equilibrium and is a passive and destabilizing policy. Besides, the output gap coefficient was unexpectedly found to be insignificant.

Synergistic enhancing effect of tungsten-copper coated graphite flakes and aluminum nitride nanoparticles on microstructure, mechanical and thermal properties of copper matrix composites

Thermal management materials with high thermal conductivity (TC), adjustable coefficient of thermal expansion (CTE) and excellent mechanical properties have promising applications in the electronic packaging and high-power density equipment fields. In this work, we have developed a novel strategy for tungsten-copper coated graphite flakes and aluminum nitride nanoparticles reinforced copper matrix composites (GFs(W–Cu)/AlN/Cu composites) fabricated by vacuum hot-pressing sintering. Herein, tungsten-copper coated graphite flakes (GFs(W–Cu)) were prepared by impregnation reduction and ultrasonic-assisted electroless plating, in which W–Cu coating improved interfacial bonding and realized metallurgical-physical synergy. Meanwhile, the AlN nanoparticles reinforced Cu flakes (AlN/Cu) were prepared by high energy ball milling, where AlN nanoparticles were evenly dispersed in the Cu matrix and played the role of pinning boundary and refining grain. Effects of nano-AlN with different volume fractions on the mechanical and thermal properties of GFs(W–Cu)/AlN/Cu composites were studied as well. As for the mechanical properties, the in-plane, through-plane flexural strength and tensile strength of GFs(W–Cu)/1.5AlN/Cu composite reached 276.7 ± 4.5, 390.6 ± 4.5 and 136.1 ± 3.0 MPa respectively, which increased by 96.8%, 283.7% and 120.7% than those of the GFs(W–Cu)/Cu composites. In terms of the thermal properties, the in-plane TC of GFs(W–Cu)/1.5AlN/Cu composite is 617.8 ± 12 Wm−1K−1, while the through-plane CTE ranging 25–200 °C is 4.9 ± 0.2 ppmK-1. In conclusion, the GFs(W–Cu)/AlN/Cu composites provide a huge potential for design and application in the thermal management materials.

Damping performance optimization of the magnetorheological damper with three parallel channels

In existing magnetorheological dampers (MRD) under impact load of launching devices, there is a contradiction between output damping force and adjustable coefficient of damping force, which is hard to cope with the harsh working conditions. To solve this problem, a new structure of three-channel MRD is proposed. The piston head is equipped with individually controllable coils and parallel three annular channels distributed on both sides of the coils. This damper greatly increases the output damping force of the three-channel MRD with ensuring a large adjustable coefficient of damping force. The multi-physical field of the damper is simulated, and damping performance of the damper under different excitation currents and single coil control is simulated. The influence of the radial position of the damping channels on the damping performance of the damper is investigated. It is demonstrated from the results that the closer of the damping channels is, the larger the output damping force of the damper is, and the maximum output damping force is 1881 N, which is 5.69 % higher than that of the existing three-channel damper. This work provides a new idea for making full use of multi-coil and multi-channel MRD structure and improving damping performance of MRD.

Assessment of turbulence and cavitation models in prediction of vortex induced cavitating flow in fuel injector nozzles

Vortex-induced cavitation develops in high pressure fuel injector equipment in areas where despite the very high surrounding pressures (>100 MPa), the rotational motion of the fluid causes large pressure drops in the core of a well-organized longitudinal vortex structure leading to cavitation with normally string type correspondingly also called string cavitation ; typically, the size of the string cavitation is small compared to the overall dimensions while they develop in a transient mode linked with the local flow turbulence. To address these complex interaction processes, some turbulence models have been tested in a diesel injector nozzle for which quantitative experimental data are available and are utilized to assess the predictive capability of relevant models; the flow has been considered compressible, turbulent and isothermal. The closure models considered include the RNG k−ε, SST k−ω, RSM, WALE LES as well as a developed very-large eddy simulation model (VLES). The employed mass-transfer cavitation models are the Schnerr and Sauer (SS), Zwart-Gerber-Belamri (ZGB), HEM and a modified ZGB model with a self-adaptive adjustment of condensation coefficient. The results indicate that the RNG k−ε model and SST k−ω model fail to predict the string cavitation induced by vortex flow in the nozzle due to the drawback of the isotropic vortex-viscosity hypothesis. The RSM model could capture an acceptable string cavitation morphology. The numerical results utilizing the VLES model and LES model are in considerably good agreement with the experimental data, while the VLES model can provide the predictions of cavitating flow as precise as that using the LES model but on a much coarser mesh. The distributions of tangential velocity are similar to the velocity characteristics of Rankin vortex or Taylor vortex, which can help understand the coherent vortex structures in string cavitating flow. It is also shown that the RSM turbulence model with modified ZGB cavitation model improves the accuracy of prediction in the vortex-induced cavitation compared to the other three cavitation models.