Structure Of Original System Research Articles

The Relationship between Purchase Money Security Interest and Title Retention

The introduction of Purchase Money Security Interest (PMSI) to our country has expanded China's system of security interests. The structures of title retention and financial lease created based on parties' consensus are blurred by the function of security, deviating from the legal property rights, ignoring the true legal meaning of parties, and resulting in the effectiveness equivalent to security interests. Although title retention, financial leasing and PMSI all have the functional value of guaranteeing price claims, and Article 388 of the Civil Code has enriched the content of guarantee contracts by introducing the registration opposition rule into atypical guarantees, we should still adhere to the system logic of the dichotomy between property and debt in the Civil Code, and draw a clear line between the two under the principle of legal property rights. The influence of guarantee functionalism should be limited to expanding the scope of "other contracts with guarantee functions" in Article 388 of the Civil Code. The retention of ownership and financial lease in Article 57 of the Judicial Interpretation on the Guarantee System are actually linked to PMSI after being attached with various conditions, which is fundamentally different from the original system structure of Articles 641 and 735 of the Civil Code.

Asymmetric Measurement-Device-Independent Quantum Key Distribution through Advantage Distillation.

Measurement-device-independent quantum key distribution (MDI-QKD) completely closes the security loopholes caused by the imperfection of devices at the detection terminal. Commonly, a symmetric MDI-QKD model is widely used in simulations and experiments. This scenario is far from a real quantum network, where the losses of channels connecting each user are quite different. To adapt such a feature, an asymmetric MDI-QKD model is proposed. How to improve the performance of asymmetric MDI-QKD also becomes an important research direction. In this work, an advantage distillation (AD) method is applied to further improve the performance of asymmetric MDI-QKD without changing the original system structure. Simulation results show that the AD method can improve the secret key rate and transmission distance, especially in the highly asymmetric cases. Therefore, this scheme will greatly promote the development of future MDI-QKD networks.

Dynamic compensation control strategy of DC bus voltage based on residual generator.

Aiming at the problem of bus voltage control in DC microgrid, a dynamic compensation control strategy based on a residual generator is designed to complete the voltage compensation of DC-DC converter. Firstly, based on the DC microgrid system architecture, the bus voltage fluctuations are analyzed theoretically, and then the DC-DC converter state-space mathematical models of the DC microgrid system are established to obtain the input-output relationship of the control system. Based on the theory of double coprime decomposition and Youla parameterization stable controller, the proposed control architecture based on the residual generator is obtained, and the output value generated by the current disturbance is compensated in reverse by applying model matching theory. The voltage loop compensation controller Q(s) is obtained by the linear matrix inequality method (LMI), and the current loop compensation controller H(s) is designed according to the dynamic structure diagram of the DC-DC converter. Hardware-in-the-loop simulation (HILS) results show that the architecture can improve the dynamic performance of the DC-DC converter without changing the original system structure parameters, and suppress the DC bus voltage fluctuations caused by load switching, power fluctuations, and AC-side load imbalances, and enhance the robustness of the system.

Application of Multislice Spiral CT in Diagnosis of Ankle Joint Sports Injury

In recent years, with the continuous improvement of medical treatment at home and abroad, computerized tomography (CT) technology has developed rapidly. The market competition at home and abroad is becoming increasingly fierce. The manufacturing cost of CT machines is highly valued by manufacturers. Reducing the manufacturing costs of CT machines is of great significance to medical equipment companies. The CT host is composed of a fixed control system and a rotation control system. Based on the analysis of the existing CT host system structure, this paper designs and implements a set of low-cost asynchronous variable-frequency rotation control systems based on the unchanged control interface of the existing main rotation servo control system, improving the market competitiveness of the product. Based on the constant structure of the rotating machine of the CT machine, the simulation analysis of asynchronous variable frequency control is carried out. A set of asynchronous variable frequency control design schemes and multi-stage speed curve control methods compatible with the original system structure are obtained. The verification and analysis of the functions of acceleration and deceleration control, rotation positioning, fault protection, electromagnetic radiation and other functions at the highest speed meet the system’s main performance requirements, such as acceleration and deceleration time at the highest speed, positioning accuracy, and speed stability. Through internal system verification, testing and clinical verification, the control system designed in this paper meets the design requirements. According to experimental data, the system is fully compatible with a running accuracy of 0.3%. The main performance indicators such as acceleration time and positioning accuracy have been improved. The acceleration time from static acceleration to the maximum speed of 0.39 seconds per revolution increases from 21 seconds to 19.9 seconds, and the positioning accuracy was improved from 0.3° to 0.24°. Finally, this study explores the diagnostic value of multislice spiral CT (MSCT) in ankle trauma.

A novel environmental control system facilitating humidification for commercial aircraft

Extreme aircraft cabin air dryness during cruise has aroused wide concern throughout the past 30 years. A new integrated system featuring air supply, pressure regulation, temperature control, water separation, and cabin humidification is proposed based on numerous field investigations, existing cabin humidification methods, and conventional aircraft environmental control systems. Cabin humidification is realized through the injection of purified water into the suction side of cabin environmental control system compressor without changing the original system structure. Another advantage of the new system is the lower demand of ram air benefitted from the decreased temperature of compressor inlet with water injection process. System analysis models and software using enthalpy parameter method are also presented. Verification experiments focused on the core parts of the integrated system show that the system analysis models agree with the experimental data well. System performance characteristic and fuel penalty are evaluated using thermodynamic analysis parameters. Results show that under 5 g/(kg·dry air) humidification, the cabin humidity increased smoothly to about 27.9% during the cruising state. The fuel penalty decreased by 1% under the new integrated system for the lower demand of ram air. The novel integrated system is effective and economy.

Performance Improvements of Switching Control for Wind Turbines

Modern variable speed wind turbines operate within a large range of wind speeds. Control of such a turbine is partitioned in two modes: a low wind speed mode and a high wind speed mode. Depending on the prevailing wind speed, a turbine is controlled to switch between these two modes. During mode switching, critical dynamics of the turbine such as the output power and mechanical loads can experience steep, large changes even though the switching action is Lyapunov as well as input–output stable. In this work, a new control technique is presented to attenuate the steep and large volatile dynamics during turbine switching while preserving the original system structure so that the established system stability still holds. An algorithm that modifies the generator torque control law in the low wind speed mode is developed to reduce the steep change of turbine power and torque. A Proportional-integral (PI) control of blade pitch angle in the high wind speed mode is proposed to optimize the system power variation and power generation. Simulations conducted under various wind speed classes demonstrate the effectiveness of the proposed control design.

Analysis of Minimal LDPC Decoder System on a Chip Implementation

This paper presents a practical method of po- tential replacement of several different Quasi-Cyclic Low- Density Parity-Check (QC-LDPC) codes with one, with the intention of saving as much memory as required to imple- ment the LDPC encoder and decoder in a memory-con- strained System on a Chip (SoC). The presented method requires only a very small modification of the existing encoder and decoder, making it suitable for utilization in a Software Defined Radio (SDR) platform. Besides the analysis of the effects of necessary variable-node value fixation during the Belief Propagation (BP) decoding algo- rithm, practical standard-defined code parameters are scrutinized in order to evaluate the feasibility of the pro- posed LDPC setup simplification. Finally, the error per- formance of the modified system structure is evaluated and compared with the original system structure by means of simulation.

Structure-preserving model order reduction by general orthogonal polynomials for integral–differential systems

For the model order reduction (MOR) of large integral–differential system, how to preserve the featured structure of original system is critical. In this paper, an orthogonal polynomials-based MOR method in time domain for the integral–differential system is presented, which is effective for preserving the structure of the original system. This method directly approximates the time response of the original system. The method is presented via an equivalent state-space system, resulting in an integral–differential reduced system. The stability of the resultant reduced system can be guaranteed under certain conditions. The error between the original system and the reduced system can be estimated. Three benchmarks in practical applications are assessed by employing different MOR methods. Compared to the moment matching method and approximate balancing truncation method, the proposed method possesses superior performance.

Finite-time stabilizing a fractional-order chaotic financial system with market confidence

A novel integer-order chaotic financial system is proposed by considering market confidence into a three-dimensional financial system. A four-dimensional fractional-order financial system is presented by introducing fractional calculus into the new integer-order system. The 0–1 test algorithm is employed to identify chaos. A robust controller is designed to stabilize the fractional-order chaotic system in a finite time. This finite-time control scheme can keep the original structure of system as much as possible and can be applied to stabilizing other chaotic systems including dynamic economic systems. Numerical simulations validate the main results of this work.

Substructuring and model reduction of pipe components interacting with acoustic fluids

This paper presents a model reduction and substructure technique for reduced dynamical models of fluid-filled pipe components. Both linear acoustical domain and structural domain are modelled by finite elements (FE), and they are fully coupled by a fluid–structure interface. The discretised dynamic FE-equations, which use the acoustic pressure as field variable in the fluid, render both non-symmetric mass and stiffness matrices due to the FSI-coupling. Since the partial solutions to the eigenproblem of the coupled system are of special interest, either numerical preconditioning or non-dimensionalisation of the physical quantities is performed to improve the condition and to accelerate the numerical computation. An iterative subspace solver is adopted to generate a sufficient approximate of the low-frequency eigenspace of the constrained problem. Model reduction for component mode synthesis uses constraint modes together with the computed eigenspace. Single-point constraints for the nodal degrees of freedom hold at the interface between substructures. The null space resulting from a QR-decomposition of the single-point constraints at the interface is used as explicit coupling matrix to prevent the deterioration of the conditioning. Partitioning of the reduction space and coupling matrices leads to a structure of the coupled global system matrices, which is similar to the original system structure in physical quantities. Therefore, the iterative subspace eigensolver is used again for numerical modal analysis. Modal analysis is performed for a pipe segment assembled by fully coupled two-field substructures. The results are compared to the results obtained from the full model and to experimentally determined mode shapes.

State-space for non-linear algebraically constrained dynamical systems

Non-linear state differential equations x = f(x, u) with algebraic constraints g(x, u, e) = 0, e = e (t), which describe possibly singular systems, are considered. The derivation of equivalent unconstrained state differential equations x* = f* (x*, e, ė,...), {x* }c:{x} ≥ {x} with the ‘ output’ equations u = h*(x*, u*, e, ė,…) and x equals; h* * (x*, e, ė…) is studied. Instead of an extension of the linear matrix-oriented singular system theory, the non-linear system inversion ideas are found to be easily applicable, to preserve much of the original system structure, and to give insight into the possibly distributional behaviour of and the possible incompatibilities in the system.

Lyapunov stability of interconnected systems: Decomposition into strongly connected subsystems

New Lyapnnov results for uniform asymptotic stability, exponential stability, Instability, complete instability, and uniform ultimate boundedness of solutions for a class of interconnected systems described by nonlinear time-varying ordinary differential equations are established. The present results make use of graph theoretic decomposition techniques to transform large-scale systems into an interconnection of strongly connected components (subsystems), and they also make use of the properties of stability preserving mappings. The analysis of the overall interconnected system is then accomplished in terms of the qualitative properties of the subsystems (strongly connected components) and the stability preserving properties of the system interconnections. A typical result is of the following form. If every subsystem (strongly connected component) is uniformly asymptotically stable and if all system interconnections are stability preserving, then the overall interconnected system is uniformly asymptotically stable. To demonstrate the applicability of these results to physical systems, a specific example is considered. The principal advantages of the present method over existing Lyapunov results for interconnected systems are as follows. 1) The present results make it possible to address the largeness of complex systems, since the identification of the strongly connected components (subsystems) can be accomplished by means of efficient computer algorithms. 2) The present stability results are applicable to interconnected systems with unstable subsystems (i.e., the original nontransformed system description may involve unstable subsystems). The main disadvantages of the present method over many existing Lyapunov results are the following. 1) The analysis is not accomplished in terms of the original system structure. 2) When a system consists of only one strongly connected component, the present method cannot be used to advantage, while other methods may.

Design techniques for high feedback gain stability

Two design techniques that ensure the stability of linear multivariable systems for high feedback gains are introduced. The first one copes with non-square systems and presents a squaring-down method which guarantees that all the root-loci of the system will stay at the left half-plane for high values of the feedback gain. The second technique achieves the same objective for the square case by means of linear state feedback or by its equivalent dynamic feedback scheme. Both methods guarantee stability, irrespective of the original system structure.