Break Research Articles

Notes on the acquisition of L2 English intervention structures: a case of Japanese EFL learners

Abstract This paper discusses Japanese-speaking EFL learners’ acquisition of English object relative clauses (ORC), which have intervention (Relativized Minimality) structures. Specifically, we contrast their early understanding of the ORC and the Subject Control constructions with their late understanding of the Subject Raising (seem) construction that exhibits a structural effect of locality on the filler-gap relation. We argue that relativization and the Control structure in Japanese induce hierarchical structures on par with those in English. Therefore, the learners have acquired a way of avoiding intervention during the process of acquiring the ORC and the Control structures in Japanese. L1 grammatical knowledge helps nullify the intervention effect in acquiring the constructions in L2 English. On the other hand, it takes time for them to overcome the effect by learning the seem raising structure with a specific strategy because Japanese does not have a construction similar to it. L1 Japanese critically influences the acquisition of L2 English with respect to the intervention configurations.

Second‐Harmonic Ripple in Two‐Stage Single‐Phase Photovoltaic Inverters: Analysis and Mitigation

ABSTRACTTwo‐stage single‐phase photovoltaic inverters exhibit a second‐harmonic ripple at the dc‐link voltage, which can cause variations in the terminal voltage of the photovoltaic array, reducing the efficiency of the maximum power point tracking (MPPT). Initially, this work investigates the efficiency reduction caused by the second‐harmonic component using analytical models. Besides, this work explores a control technique to reduce the ripple in the terminals of the photovoltaic module based on real‐time normalization of the dc/dc converter control signal. This technique is compared with conventional control and with the addition of second‐harmonic resonant control. The case study is based on a 4.4‐kVA/220‐V photovoltaic inverter with input for two photovoltaic strings. The results indicate that both techniques are capable of performing the attenuation of the voltage ripple at the terminals of the photovoltaic array, resulting in efficiency gains in the order of 0.74% for the strategy based on resonant control and 0.95% for the proposed normalization technique. In addition, C‐HIL and experimental results prove the reduction in voltage ripple with the normalization and resonant control. As an advantage, the normalization technique is simpler than the second one, because it does not require modification of the control structure of the dc/dc converter.

Adaptive Weighted Particle Swarm Optimization for Controlling Multiple Switched Reluctance Motors with Enhanced Deviatoric Coupling Control

Switched reluctance motors (SRMs) are widely used in industrial applications due to their advantages. Multi-motor synchronous control systems are crucial in modern industry, as their control strategies significantly impact synchronization performance. Traditional deviation coupling control structures face limitations during the startup phase, leading to excessive tracking errors and exacerbated by uneven load distribution, resulting in desynchronized motor acceleration and increased speed synchronization errors. This study proposes a modified deviation coupling control method based on an adaptive weighted particle swarm optimization (PSO) algorithm to enhance multi-motor synchronization performance. Traditional deviation coupling control applies equal reference torque inputs to each motor’s current loop, failing to address uneven load distribution and causing inconsistent accelerations. To resolve this, a gain equation based on speed deviation is introduced, incorporating self-tracking error and gain coefficients for dynamic synchronization error compensation. The gain coefficients are optimized using the adaptive weighted PSO algorithm to improve system adaptability. A simulation model of a synchronization control system for three SRMs was developed in the Matlab/Simulink R2023b environment. This model compares the synchronization performance of traditional deviation coupling, Fuzzy-PID improved structure, and adaptive PSO improved structure during motor startup, sudden speed increases, and load disturbances. The validated deviation coupling control structure achieved the initial set speed in approximately 0.236 s, demonstrating faster convergence and a 6.35% reduction in settling time. In both the motor startup and sudden speed increase phases, the two optimized methods outperformed the traditional structure in dynamic performance and synchronization accuracy, with the adaptive PSO structure improving synchronization accuracy by 54% and 37.17% over the Fuzzy-PID structure, respectively. Therefore, the PSO-optimized control system demonstrates faster convergence, improved stability, and enhanced synchronization performance.

Liquid crystal phase behavior of oxalated cellulose nanocrystal and optical films with controllable structural color induced by centripetal force

Cellulose nanocrystal (CNC) is a sustainable bio-nanomaterial. The distinctive left-handed polarization properties render cellulose nanocrystal a promising candidate for optical film. Due to eco-friendliness, reliability, mildness and simplicity, the oxalate hydrolysis method stands out among various preparation methods for CNC. This study delved into the liquid crystal phase behavior of oxalated cellulose nanocrystal derived from pulp, and discovered the influences of CNC concentration and pH on suspension stability and phase transition, and evaluated its optical properties. The results demonstrated that oxalated CNC presented two different liquid crystal phases, the nematic phase and the cholesteric phase. The stability mechanism of CNC suspension and the regulatory principle of the liquid crystal phase transition were revealed. A novel CNC film-forming technology, the multilayer spin-coating technique, was developed for cellulose nanocrystal optical films. Driven by centrifugal force, cellulose nanocrystals were induced to self-assembly and formed the optical film with circular dichroism and structural color. This simple and efficient film-forming technology promised rapid processing (1 h) and controllable film structure and optical properties compared to traditional technologies. This work provided a theoretical understanding and practical prospects for integrating oxalated cellulose nanocrystal into sustainable advanced optical film materials.

Application of systems safety principles for O&M of floating offshore wind

Abstract The offshore wind industry is growing rapidly and is also a high risk industry with unique safety challenges. As the industry grows, more research is needed to make sure it operates safely and provides a workplace in which all involved can go home free of injury. The adoption of floating wind turbines brings new hazards and increased complexity to offshore wind operations and maintenance. Floating wind operations will involve the development of new deepwater sites and require the adoption of new strategies such as floating to floating transfers and towing operations. As the complexity of offshore operations increases it is important that the understanding of the hazards involved are developed. Floating wind is a new branch of the offshore wind industry and as technologies and systems have yet to become established there is the opportunity to do things differently and embed safety improvements in the industry from the outset. This study has looked at the potential application of systems safety theories to floating wind operations and maintenance. The application of systems engineering to improve safety performance has been growing across many industries in recent years. Systems safety considers that safety is an emergent property of a complex system that is a result of many interacting factors. This study looks at how systems safety could be applied to the emerging floating wind industry to build safety into the industry at the earliest stages. This study reviewed the applications of systems safety across similar industries and the offshore wind industry. It then looks at existing hazards of floating wind that have already been identified in the literature and completed a systems theory hazard analysis of floating wind O&M activities. This involved the mapping of the safety control structure for floating wind operations and the identification of potential gaps between the safety controls and safety requirements. It then explores how systems safety processes could be applied to floating wind and makes recommendations for how these could be implemented to the emergent industry. The study found existing research of systems safety applied to the offshore wind industry is currently very limited. Its application has been successful in similar industries and there is potential for a systems safety approach to be used in the development of floating wind operations and maintenance. The systems theory hazard analysis can help identify potential systemic risks arising as a result of the interaction of multiple systems. It can be used to develop appropriate control structures to manage safety and could also be used for the identification of leading indicators to manage safety performance.

Design and optimization of a planar anti-buckling compliant rotational joint with a remote center of motion

Compliant mechanisms (CMs) exhibit some excellent mechanical properties and provide numerous innovative solutions for many existing mechanical applications. Among them, planar compliant rotational joints have made substantial contributions to precision engineering. To achieve high-precision positioning with a compliant rotational joint, it is essential to study characteristics such as anti-buckling and constant stiffness. The remote center of motion (RCM) mechanism, with its compact structure and ease of precise control, is expected to enhance overall rigidity and reduce parasitic displacements. Here, we propose a planar anti-buckling compliant rotational joint with a RCM. Static modeling and model validation are conducted for different geometric configurations, including single and combined structures. A distributed configuration with bidirectional anti-buckling properties is selected for optimization. Using a global parameter optimization model, single-objective optimization studies are conducted for three distinct characteristics. Subsequently, a multi-objective optimization model for constant stiffness and high precision is established. Based on the optimization results, a compliant rotational joint with bidirectional anti-buckling, constant rotational stiffness, and high precision is designed. Finally, the effectiveness of the optimization method is validated through physical experiments.

A study of automatic output power control methods for stand-alone photovoltaic power generation systems

Abstract The conventional power generation system’s output power automatic control structure is generally unidirectional, and the control coverage is small, leading to the increase in the random error obtained in the final test. Therefore, the design and research of this article are proposed. According to the current control demand, the generation system shall be stabilized first, and the power compensation shall be calculated. The multi-step mode shall be adopted to improve the control coverage and design the multi-step automatic control structure. According to this, it is constructed, and the automatic control processing is realized using jump balance. The test results show that compared with the traditional DFIG-DRWT system power output automatic control method and the traditional three-phase asynchronous generation system power output automatic control method, the random error finally obtained by the designed independent photovoltaic power station output power automatic control method is relatively effective. This indicates that the application effect and coverage of the designed power automatic control method are high, that controllability has been significantly improved, and that control flexibility has also been strengthened.

Synthesis and Advanced Applications of Transition Metal Oxides

Transition metal oxide semiconductor materials have gained significant attention in recent years because of their unique electrical, magnetic, and optical features. Transition metal oxides (TMOs) with partially filled d-shells have a wide range of characteristics and play important roles in a variety of technological applications. They are influenced by stoichiometry changes, which alter their physical, chemical, and electrical properties. Controlled synthesis, doping, and post-synthesis treatments can all have an impact on the size, shape, crystal structure, and overall attributes of TMOs. These changes affect applications such as magnetic materials and smart windows. Effective techniques include valence state control, dopants, alloying, structure engineering, nano and defect structuring, and surface modification. This article discusses the synthesis methods, crystal structures, electrical properties, and applications of transition metal oxides, as well as their involvement in cutting-edge technologies such as electronics, optoelectronics, energy storage, and catalysis.

Proposed Technique for Estimating Rainwater Storage Tank Locations Using Vulnerability Analysis of Critical Flooding Nodes

Even if a pumping station, which is a representative structural flood defense facility, operates optimally, flooding occurs at certain nodes in the drainage area. In other words, even if rainwater pumping stations and rainwater storage tank, which are structural flood defense measures, operate at maximum, it is necessary to review areas where overflow occurs. Therefore, in areas where it is impossible to protect against inland flooding using structural flood defense measures alone, new flood defense measures are required. In this study, based on previous research on rainwater pumping station operation techniques to reduce critical flooding, the Daelim 3 region was divided into 45 basic areas and vulnerability analysis techniques were applied to select the location of rainwater storage tank for effective flood defense. A possible technique is presented in this paper. As a result of the study, sub-region 1 had the highest impact index value, so installing a rainwater storage tank was calculated to be more effective in preventing floods than installing a rainwater storage tank in other sub-regions. The priority-estimation technique for flood defense facilities presented in this study can be effective in establishing plans for flood control structures other than rainwater storage tank.

Integrating subject-specific workspace constraint and performance-based control strategy in robot-assisted rehabilitation

IntroductionThe robot-assistive technique has been widely developed in the field of neurorehabilitation for enhancement of neuroplasticity, muscle activity, and training positivity. To improve the reliability and feasibility in this patient–robot interactive context, motion constraint methods and adaptive assistance strategies have been developed to guarantee the movement safety and promote the training effectiveness based on the user’s movement information. Unfortunately, few works focus on customizing quantitative and appropriate workspace for each subject in passive/active training mode, and how to provide the precise assistance by considering movement constraints to improve human active participation should be further delved as well.MethodsThis study proposes an integrated framework for robot-assisted upper-limb training. A human kinematic upper-limb model is built to achieve a quantitative human–robot interactive workspace, and an iterative learning-based repulsive force field is developed to balance the compliant degrees of movement freedom and constraint. On this basis, a radial basis function neural network (RBFNN)-based control structure is further explored to obtain appropriate robotic assistance. The proposed strategy was preliminarily validated for bilateral upper-limb training with an end-effector-based robotic system.ResultsExperiments on healthy subjects are enrolled to validate the safety and feasibility of the proposed framework. The results show that the framework is capable of providing personalized movement workspace to guarantee safe and natural motion, and the RBFNN-based control structure can rapidly converge to the appropriate robotic assistance for individuals to efficiently complete various training tasks.DiscussionThe integrated framework has the potential to improve outcomes in personalized movement constraint and optimized robotic assistance. Future studies are necessary to involve clinical application with a larger sample size of patients.

Dynamic Operational Planning in Warfare: A Stochastic Game Approach to Military Campaigns

ABSTRACTWe study a two‐player discounted zero‐sum stochastic game model for dynamic operational planning in military campaigns. At each stage, the players manage multiple commanders who order military actions on objectives that have an open line of control. When a battle over the control of an objective occurs, its stochastic outcome depends on the actions and the enabling support provided by the control of other objectives. Each player aims to maximize the cumulative number of objectives they control, weighted by their criticality. To solve this large‐scale stochastic game, we derive properties of its Markov perfect equilibria by leveraging the logistics and military operational command and control structure. We show the consequential isotonicity of the optimal value function with respect to the partially ordered state space, which in turn leads to a significant reduction of the state and action spaces. We also accelerate Shapley's value iteration algorithm by eliminating dominated actions and investigating pure equilibria of the matrix game solved at each iteration. We demonstrate the computational value of our equilibrium results on a case study that reflects representative operational‐level military campaigns with geopolitical implications. Our analysis reveals a complex interplay between the game's parameters and dynamics in equilibrium, resulting in new military insights for campaign analysts.

Performance study of an innovative dual injection mode injector for marine low-speed dual-fuel engine

Marine low-speed dual-fuel engines typically have two sets of fuel injection system, main-injection and micro-injection. In order to make the fuel injection system of marine low-speed dual-fuel engine compact in structure and flexible in injection control, an innovative dual injection mode injector (DIMI) which can achieve both the functions of main-injection and micro-injection was proposed. The switching between main-injection and micro-injection mode of the injector is achieved through the collaborative control of dual solenoid valves. Based on the constructed AMESim model, the injection quantity characteristic and hydraulic efficiency of the DIMI were investigated under different working conditions and injection modes. The results show that, when the DIMI in main-injection mode achieves injection quantity characteristic similar to those of a traditional electronically controlled injector (TECI), the electromagnetic forces of solenoid valves of the DIMI are less required to 80% of that of the TECI, and the fuel return quantity and hydraulic efficiency of the DIMI are comparable to those of the TECI under the same working conditions. By changing the minimum limit height of the needle of the DIMI under micro-injection mode, different ranges of micro-injection quantity could be designed according to the requirements of the engine, and the control accuracy of injection pulse width (IPW) on micro-injection quantity is higher than on main-injection quantity. Both the hydraulic efficiency of the DIMI under main-injection and micro-injection mode increase with the rail pressure and IPW in the small IPW range, then gradually tend to be saturated with the increase of IPW. As the minimum limit height of the needle increases, the injection quantity and hydraulic efficiency of the DIMI under micro-injection mode increases overall, however, the saturation values of the hydraulic efficiency in micro-injection mode under different needle minimum limit heights are still smaller than those in main-injection mode.

Application of polymer adhesive hydrogel in wound healing

As the global adhesive industry continues to grow, researchers are discovering that polymer adhesives are playing an increasing role in the medical field, polymer adhesives have attracted more and more attention from the medical industry due to their unique advantages, such as hydrogels, have gradually appeared, which can effectively help wound healing. Most of the hydrogels have good biocompatibility and water absorption, and have the advantages of controllable structure, adjustable performance and easy degradation. Compared with traditional wound healing methods, hydrogels effectively reduce additional trauma and leakage and allow for greater tissue integration. This paper reviews the types of polymeric adhesive hydrogels and examples of some of them being artificially modified to be applied to the field of wound healing. Analyzes their mechanism of action and the advantages and shortcomings of their clinical applications, and finally looks into the potential functions and clinical efficacy of hydrogels in the future.

Control Structures for Combined H2/Electricity from Offshore Wind Turbines

Wind energy proves to be a highly favourable choice for electricity generation due to its clean and renewable nature, and is playing a significant role in reducing global greenhouse gas emissions. Offshore wind turbine systems have gained widespread popularity as they can capitalise on elevated and consistent wind speeds surpassing those found in onshore locations, resulting in increased energy efficiency. Furthermore, offshore wind power possesses the potential to emerge as a significant electricity source for the production of green hydrogen. As water electrolysis technology for hydrogen production continues to advance, utilizing offshore wind power for hydrogen generation is becoming more economically viable and practical. Offshore wind power with higher wind speeds in combination with efficient control structures presents an attractive option for electricity generation and hydrogen co-production. This paper aims to present and evaluate four different production structures for combined H2/energy generation from offshore wind turbines. Previous research studies in this area often overlook control structures and lack information on power converter operations. In contrast, this article studies control structures that enable proper functionality and ensure adequate interoperability, enhancing the reliability of renewable energy integration. Each structure, including both wind turbines and electrolyser, is described in detail, along with the corresponding controllers. Simulation results are presented for each structure and controller to demonstrate their effective operation.

Atomic‐Level Synergistic Catalysts: Single‐Atom Site Integrated with Atom, Cluster and Nanoparticle

AbstractThe emerging atomic‐level synergistic catalysts based on the single‐atom sites and other valuable components, such as atom, cluster, nanoparticle and other nano‐matter, shine in various catalytic fields. They can integrate the advantages of individual catalytic sites and other valuable components to enhance the activity, selectivity and stability of many chemical reactions via activating their key rate‐determining steps and multistep transformations. In addition, because of the ultrahigh atom utilization (~100 %) and adjustable microenvironment of metal centers, the single‐atom sites can intelligently construct with other useful large size sites to strengthening in tandem a typical catalytic process. Herein, the structure and mechanism of atomic‐level synergistic catalysts with controllable electronic structures and regulatory reaction processes are presented. We particularly emphasize the interactions between active components of atomic‐level synergistic catalysts and catalytic reaction processes, which are essential for understanding how these catalysts are cooperatively working. It is anticipated that this minireview can make the promotion of advanced atomic‐level synergistic catalysts based on single‐atom sites.

Optimal Energy Management Systems and Voltage Stabilization of Renewable Energy Networks

This paper addresses the challenge of integrating multiple energy sources into a single-domain microgrid, commonly found in urban buildings, while also providing a platform for energy management. A Lyapunov stability analysis of a simple boost converter was used as a basis for designing the dual control loop of the grid. The versatility of the developed control structure allows for the incorporation of an arbitrary number of sources hence achieving scalability. Next, the energy in the microgrid was separated into exogenous energy and actuator energy. This yielded a description of the system that quantified the condition of stability independent of the decision made by a would-be energy management system. This, in turns, liberates the process of designing an optimized energy management system from stability concerns. The acquired theoretical findings were then translated to a simulation model, where multiple components of the grid were simulated under a typical scenario of operation. Once the simulation phase was concluded, a prototype of the designed grid was constructed to emulate the theoretical results. The prototype exhibited promising performance, matching the simulation predictions to a reasonable degree.

NoviCode: Generating Programs from Natural Language Utterances by Novices

Abstract Current Text-to-Code models demonstrate impressive capabilities in generating executable code from natural language snippets. However, current studies focus on technical instructions and programmer-oriented language, and it is an open question whether these models can effectively translate natural language descriptions given by non-technical users and express complex goals, to an executable program that contains an intricate flow—composed of API access and control structures as loops, conditions, and sequences. To unlock the challenge of generating a complete program from a plain non-technical description we present NoviCode, a novel NL Programming task, which takes as input an API and a natural language description by a novice non-programmer, and provides an executable program as output. To assess the efficacy of models on this task, we provide a novel benchmark accompanied by test suites wherein the generated program code is assessed not according to their form, but according to their functional execution. Our experiments show that, first, NoviCode is indeed a challenging task in the code synthesis domain, and that generating complex code from non-technical instructions goes beyond the current Text-to-Code paradigm. Second, we show that a novel approach wherein we align the NL utterances with the compositional hierarchical structure of the code, greatly enhances the performance of LLMs on this task, compared with the end-to-end Text-to-Code counterparts.

Linear strain gradient-regulated bifurcation of circular bilayer plates

Bilayer structures with controllable self-folding capability have found applications in a variety of cutting-edge fields such as flexible electrics, wearable devices and soft robotics. The folding of bilayer structures occurs when the mismatch strain between the two layers exceeds the bifurcation threshold, resulting in a deformation transition from an axisymmetric to a folded state. Previous efforts have predominantly focused on bilayer structures with uniform and/or anisotropic strain distributions. However, the role of non-uniform in-plane strain distributions in regulating the bifurcation of bilayer structures has not been fully understood. In this study, the effects of linear in-plane strain gradients on the bifurcation of circular bilayer plates, both with and without geometric mismatch, are systematically investigated by combining theoretical analysis, finite element simulations and experiments. Our results reveal that both the mismatch strain gradient and the geometric mismatch between the two layers play crucial roles in regulating bifurcation. Notably, linear mismatch strain gradients with larger strain at the center delay bifurcation, while those with larger strain along the edge promote bifurcation. This work offers new insights into the design of controllable self-folding bilayer structures, which is of great significance for advanced applications.

Comparative study of the two DTC (6S - 12S) approaches applied to PMSM equipped with an IP regulator

Direct torque control was introduced in 1980 for induction machine for torque and flux control and developed for MSAP in 1990. DTC is gaining popularity due to its simple control structure and easy implementation. The principle of direct torque control (DTC) of the asynchronous machine was introduced in 1985 by I. Takahashi as an alternative to flux-directed vector control (FOC). It is thanks to its simple control structure that it gains popularity and its easy implementation that it has opened a new horizon in the field of variable speed control of electric drives. Indeed, direct torque control (DTC) has benefited in recent years from significant methodological advances in operation and technological development following the introduction of power electronics and digital electronics and the implementation of possible and very usable control algorithms. In conjunction with these technological advances, the scientific community has developed several control approaches to control the operation of electrical machines. In this context, this article presents a comparative study of the different direct torque control (DTC) strategies and structures of the permanent magnet synchronous machine (MSAP). We propose the algorithm of this control making it possible to provide solutions to the ripples of the torque and the stator flux in order to reduce them by adopting a method of compensating the effects of progression by passing from the six sector DTC (DTC – 6S: classic and modified) then develop the twelve-sector DTC (DTC-12S) whose purpose is to minimize ripples and control the switching frequency of the inverter. The simulation graphs presented will clearly show the difference between the different controls techniques cited.

Generation of partially coherent full Poincaré beam arrays and their Stokes scintillations in turbulent media

A type of vector beam arrays, called partially coherent full Poincaré (PCFP) beam arrays, is introduced and experimentally synthesized using modal-vector-decomposition method. Our experimental system involves a digital micro-mirror device, which can generate such beam arrays with controllable spatial coherence and array structure in almost real-time, enabling to test the impact of atmospheric turbulence on them. Furthermore, we experimentally examine the scintillations of four Stokes parameters (denoted as S0, S1, S2, and S3) of PCFP beam arrays propagating through lab-simulated turbulence. The results indicate that the Stokes scintillations decrease as the number of beamlets increase or spatial coherence decreases. In contrast to S0 scintillation (intensity scintillation), S1, S2, or S3 scintillation is less affected by the turbulence under the same conditions. Our experimental results show that S2 and S3 scintillations could reduce by 67.2% and 52.4% compared to the intensity scintillation in strong turbulence. Our findings have potential applications in free-space optical communication when the Stokes parameter S2 or S3 is served as an information carrier.