Multiple Operation Modes Research Articles

Injection-locked range and linewidth measurements at different seed-laser linewidths using a Fabry–Pérot laser-diode

In this paper we experimentally examine the dependence of the injection-locked range magnitude of a Fabry–Perot (FP) laser on the linewidth of a seed laser. We measure the enhancement of the incident-power-dependent injection-locked range when changing the seed-light linewidth in three different ranges, starting with tens of GHz, then hundreds of MHz, and up to a few hundred kHz. We notice the progressive shrinkage of the locking range with an increase in the linewidth of the seed source. Simultaneously, the linewidth of a FP laser was measured and the cancellation of multiple longitudinal operating modes as well as a great reduction of linewidth are observed with a self-homodyne measurement.

An S-graph Based Approach for Multi-Mode Resource-Constrained Project Scheduling with Time-Varying Resource Capacities

The Resource-Constrained Project Scheduling Problem (RCPSP) is a general problem class of scheduling problems. It even contains the well-known job shop scheduling problem as a special case. In these problems, jobs demand different amounts from multiple resources at once. The goal is to minimize completion time while satisfying resource capacity constraints throughout the schedule. The RCPSP has several variations and generalizations, one of which is the multi-mode problem. Multiple operation modes are given for jobs, differing in resource usages and execution times. Another generalization is where resources have time-varying capacities instead of a constant limit. The S-graph framework was developed for batch process scheduling and used successfully in various applications. The advantages of this approach motivate research to extend its capabilities to more general problem classes and apply it in various specialized case studies. The authors have previously presented an extension of the S-graph framework for RCPSP and its multi-mode generalization. In this work, a further extension is proposed for handling time-varying capacities. The method relies on a model transformation technique and recent algorithmic developments of the framework.

Simultaneous Stability of Large-scale Systems via Distributed Control Network with Partial Information Exchange

This paper is concerned with the simultaneous stability of the multi-mode large-scale systems composed of the interaction subsystems. A novel distributed control network consisting of multiple network-based controllers with the partial information exchange is adopted to simultaneously stabilize the large-scale systems in multiple operation modes. In the distributed control network (DCN), a partial state information exchange approach is developed to save the real-time communication and computation resources. To compensate for the effects of dynamic couplings between interaction subsystems, the designed controllers use both the local states and the neighbors’ partial information with packet dropouts for local feedback design. Then, a series of Lyapunov functions are constructed to derive a matrix-inequality-based sufficient condition for the existence of the desired controllers. Based on an orthogonal complement technique, the gains of the controllers in DCN are parameterized. The iterative algorithm for the solution of simultaneous stabilization problem is also developed. Finally, a numerical example is performed to show the relevant feature of the proposed method.

A New Parallel Manipulator With Multiple Operation Modes

In this work, a new parallel manipulator with multiple operation modes is introduced. The proposed robot is based on a three-degrees-of-freedom (3DOF) parallel manipulator endowed with a three-dof central kinematic chain, where by blocking some specific kinematic pairs, the robot can modify its mobility. Hence, the robot manipulator is able to assume the role of a limited-dof or a nonredundant parallel manipulator. Without loss of generality, the instantaneous kinematics of one member of the family of parallel manipulators generated by the reconfigurable parallel manipulator, the three-RPRRC + RRPRU nonredundant parallel manipulator with decoupled motions, is approached by means of the theory of screws. For the sake of completeness, the finite kinematics of the robot is also investigated. Numerical examples are included with the purpose to clarify the method of kinematic analysis.

Comparative Analysis on Chinese Typical Cross-border E-commerce Platforms

In recent years, cross-border E-commerce has become a hotspot. Development of cross-border E-commerce makes traditional export trade structure change, and more and more foreign trade enterprises acquire business opportunities through continuous online transactions. As the competition in the cross-border E-commerce industry is increasingly fierce, the cross-border E-commerce industry has been subdivided into multiple operation modes gradually. In order to help the participants of cross-border E-commerce industry clarify the development status of Chinese cross-border E-commerce, and learn to deal with various specific issues in practice, this thesis will divide the cross-border E-commerce platform into two parts, the “B2B Model” and “Retail Mode”, compare and study the development, operation, logistics and storage, and payment of different platforms in different modes, then summarize and compare the features, advantages and disadvantages of the two different modes, and finally provide improvement suggestion combining the pain points of each mode. At last, this thesis summarizes the status quo of overall cross-border E-commerce platform at present and expects to make some contribution to development of future cross-border E-commerce platform. After comparative analysis on Chinese typical cross-border E-commerce platforms in the entire thesis, it is concluded that Chinese cross-border E-commerce platform shall still improve in aspects of logistics, storage, payment, policy and talent. Only in this way can Chinese cross-border E-commerce enterprises seize opportunity to develop rapidly and make the cross-border E-commerce become the driver of cross-border trade growth.

Modelling of a Power Converter with Multiple Operating Modes

In order to achieve DC voltage matching, on-board charging, and DC/AC power inversion, three independent power converters are often needed in traditional Distributed Power Converter (DPC) systems of electric vehicles (EVs): bidirectional DC/DC (Bi-DC/DC), AC/DC, and DC/AC. The requirement of electronic devices such as power switches, inductors, and capacitors make the converter costly and complicated in structure. In this paper, a power converter with multi-operating mode (PCMM) is presented. The proposed PCMM can work in Bi-DC/DC, AC/DC, and DC/AC modes. The state-space averaging model of PCMM considering resistance of Insulated Gate Bipolar Transistor (IGBT) and the inductor is presented. Based on this model, the transfer function of the system is derived and the controller is designed. The simulation and experimental results show that PCMM can meet the design target and verify the feasibility of the model. The measurement results show that the weight of PCMM proposed in this paper is reduced by 51.2% compared with the traditional structure.

Design of a Compliant Gripper With Multimode Jaws

This paper presents the design of a multimode compliant gripper, using the singularities of the four-bar mechanism with equilateral links. The mobility of the compliant gripper can be reconfigurable to grasp a variety of shapes or adapt to specific requirements. The compliant gripper is a compact and two-layer structure. Two linear actuators are required to enable the multiple operation modes, by the conversion of two pairs of slider-crank mechanisms. A multimode compliant four-bar mechanism is first presented and kinematically analyzed. The design and the kinetostatic modeling of the resulting compliant gripper are then performed. Finally, the analysis of the reconfigurable compliant gripper under different actuation schemes is carried out, including the comparison of the results obtained from analytical modeling, finite element analysis (FEA), and experimental testing.

Analysis of the transition between multiple operational modes for hybrid AC/DC microgrids

There are four basic operational modes for the hybrid AC/DC microgrid, including AC grid-connected while interconnecting, both off-grid while interconnecting, AC gridconnected without connection, and both off-grid without connection. How to achieve a seamless operational mode transition is an urgent technical need to overcome. First, this paper describes the typical structure of the hybrid microgrid, and places a detailed focus on the power balance and transition strategy. Secondly, it takes the master-slave control structure as an example, and designs the transition logic for different operational modes, and then a method for selecting the slack bus and transition time-sequence is proposed. Based on the different roles that the interlinking converter (IC) plays in the process of modes transition, a voltage-power (U-P) control method for a hybrid AC/DC microgrid is proposed, and the exchanged power is calculated based on the voltage deviation between the rating value and measured value. Finally, a control flowchart for the transition between the four operational modes in transition is designed. Using the PSCAD/EMTDC platform, this paper takes a typical seven-point microgrid structure as an example, the proposed transition strategy is carried out, and the results show that the transition method and time sequence can achieve smooth transition between different operational modes.

Multi-objective real-time optimization energy management strategy for plug-in hybrid electric vehicle

Plug-in hybrid electric vehicle provides remarkable results for emission reduction and fuel improvement in the current driving cycles. With the appropriate energy management strategy, the torque can be split by switching of multiple operation modes to improve fuel economy. However, in the process, not only the noticeable jerk or torque fluctuation, which may result in vibration of the drivetrain and unpleasant driving sensation, but also the frequent motor-start-engine process would be triggered, which is accompanied by extra fuel consumption and abrasion of the clutch. Therefore, high attention should be paid to reduce the excess operating times of the motor-start-engine process and take advantage of multiple operation modes to improve fuel economy in plug-in hybrid electric vehicle. To solve this problem, a multi-objective real-time optimization energy management strategy is proposed. First, the motor-start-engine dynamic model of 2-degree-of-freedom is established. Then, the motor-start-engine process is analyzed based on a large number of real-world data, and the cost of the motor-start-engine process is quantified for optimization. What’s more, the optimal torque distribution is realized through the powertrain system. Finally, the proposed strategy is verified by the simulation and experiment platform. Results show that the proposed strategy can greatly improve fuel economy, thereby reducing the excess operating times of the motor-start-engine process.

Simultaneous H∞ stabilization for large-scale systems within distributed wireless networked control framework over fading channels

In this paper, the simultaneous H∞ stabilization problem is investigated for a physically interconnected large-scale system which works in multiple operation modes. A distributed wireless networked control framework is introduced, in which the distributed dynamic output feedback controllers not only use the local measurements, but also receive the neighboring controllers’ broadcasts via wireless networks. The channel fading in wireless communications is described as the Rice fading model. Our focus is on the design of the distributed controllers such that the large-scale system is mean-square stable in each operation mode and achieves a prescribed H∞ disturbance attenuation level. By employing the Lyapunov functional method and related stochastic analysis techniques, a sufficient condition on the existence of desired controllers is presented, and the parameterization of the controller gains is derived. Finally, a numerical example is utilized to illustrate the feasibility of the proposed scheme.

32 × 32 CMOS SPAD Imager for Gated Imaging, Photon Timing, and Photon Coincidence

We present the design and simulations of a single-photon sensitive imager based on single photon avalanche diodes (SPADs) with an innovative pixel architecture that includes four separate SPADs with independent active time-gating and quenching circuit, a shared time-to-digital converter (TDC) with 50-ps resolution, four independent photon counters, and multiple operation modes. The TDC is driven by smart arbitration logic, which preserves spatial information among the four detectors; furthermore, an alternative operation mode exploits photon-coincidence on multiple detectors to reduce the effect of high background levels, e.g., in light detection and ranging applications with strong ambient light. Key features are the ability to operate in simultaneous photon counting and timing modes for capturing 2-D and 3-D images of the scene in a single shot (frame), the option of a counting-only mode, reducing power consumption, and increasing achievable frame-rate when timing information is not needed, and the ability to individually shut down noisy detectors or to enable just some regions of interests.

Multiple operating mode ANFIS modelling for speed control of HSEMU

High-speed electric multiple unit (HSEMU) is a complex non-linear system which runs under three typical operating modes (OMs) including traction, braking, and coasting. With the increasing traffic density of the high-speed railway, the conventionally manual control strategies may be inapplicable for the HSEMU to maintain a good running performance. To enhance the running performances, in this study, a novel multiple OM (MOM) running model is designed to accurately describe the non-linear relationship between running speed and controlling force. By utilising the advantages of adaptive neuro-fuzzy inference system (ANFIS) on non-linear modelling, this study proposes an MOM-ANFIS model of HSEMU. On the basis of the established MOM-ANFIS model, a new speed controller incorporated with OM selection mechanism is designed to achieve speed control of HSEMU followed by a stability analysis of the closed-loop system. Comparative experimental results using practical running data show that the proposed MOM-ANFIS model displays better modelling accuracy and the corresponding control strategy achieves improved speed control performances for the HSEMU.

An unsupervised anomaly detection approach using energy-based spatiotemporal graphical modeling

This paper presents a new data-driven framework for unsupervised system-wide anomaly detection for modern distributed complex systems within which there exists a strong connectivity among sub-systems, operating in diverse modes and encountering a large variety of anomalies. The framework is based on a spatiotemporal feature extraction scheme built on the concept of symbolic dynamics for discovering and representing causal interactions among subsystems. The extracted features from the spatiotemporal pattern network (STPN) are then used to learn system-wide patterns via a Restricted Boltzmann Machine (RBM), to form an energy based anomaly detection approach. While STPN is treated as a weak learner of system modes (in terms of difficulty in discovering true graphical representations), RBM is treated as a boosting approach to form a strong learner of system characteristics. Case studies with simulated data and real data from an integrated building system are used to validate the proposed approach. The results show that: (i) the increase in RBM free energy in the off-nominal conditions compared to that in the nominal conditions can be used for anomaly detection; (ii) the proposed framework formulates a strong learning model (STPN+RBM) from weak frequentist model–STPN, via boosting with RBM; and (iii) the STPN+RBM framework can capture multiple nominal operating modes of distributed complex systems with a single graphical model.

Abstract ID: 21 Simulation of synchrotron-based microbeam radiation therapy using Geant4

Microbeam Radiation Therapy (MRT) is a preclinical radiotherapy modality characterised by the use of many micron-sized, spatially fractionated, high intensity radiation fields produced by a Multi-Slit Collimator and synchrotron light [1] . A typical MRT radiation field consists of multiple high dose ‘peaks’ separated by low dose ‘valleys’ (width 25–50 μm; pitch 100–400 μm) delivered with dose rates of up to 10 kGy/s. The minute field size and high dose rate of MRT requires good Quality Assurance in order to transition into the clinical field. Dose Verification and Treatment Planning Systems (TPS) are crucial aspects of quality assurance, allowing for independent prediction and verification of dose distributions delivered to patients. The most accurate form of TPS is Monte Carlo computer simulations. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has developed a Geant4-based synchrotron beamline model for dose verification at the Australian Synchrotron Imaging and Medical Beamline (IMBL). This model, denoted G4IMBL, uses a multi-stage procedure to generate synchrotron light, transport through the beamline model, and calculate dose deposition in a phantom. G4IMBL models the production of X-ray photons entirely using Geant4 by transporting electrons through the sinusoidal magnetic field of a wiggler. This allows for optimisation of multiple operation modes via tuning of wiggler magnetic field strength and electron steering angle. The simulation has been validated against experimental measurements and is used to characterise novel Quality Assurance silicon based detectors with sub-mm spatial resolution, developed at CMRP. The development, optimisation, and validation of this Geant4-based software tool for MRT Quality Assurance will be presented.

Grouped Genetic Algorithm Based Optimal Tests Selection for System with Multiple Operation Modes

To insure various operation modes operated properly, important modules or potential fault sources must be monitored. Due to the hardware resource limit, only part of modules and potential faults can be covered by online test. The percentage of modules or fault sources been covered is termed as fault detection rate (FDR). Lower mode FDR constraints must be satisfied to insure the whole mission executed successfully. It’s a typical multi-constraint optimization problem. In this paper, a grouped genetic algorithm (GGA) is proposed to minimize the test cost and satisfy the FDR constraints. Each GA is used to optimize the test set for one mode. The final chromosome of each GA represents the selected tests in one mode. The union set of the chromosomes of all GAs gives the final solution. Each GA is subjected to one FDR constraint, therefore, the optimal solution is more likely be found. The group of GAs are executed in parallel, hence, the proposed method is efficient. The effectiveness and efficiency of the proposed method are verified by statistical experiments.

Multi-operation laser oscillator: an example of multi-operation laser

A multi-operation laser oscillator is developed and built with multiple operation modes (OMs): injectionseeding mode, cavity-dumping mode and Q-switching mode.With the same electrical energy pumping, the multioperation laser oscillator provides different output energies and pulse durations for different OMs. In the Q-switching mode, the output coupling is optimized for different electrical energy pumping. The laser oscillator operation can be switched between different modes conveniently. The multi-operation laser sources could be operated in multiple OMs for various research and application requirements.

State Estimation of Thermal Systems with Multiple Operation Modes

The state estimation of thermal systems with multiple operation modes is considered. Based on a description as hybrid dynamical systems, we reduce it into an observer design problem for switched linear systems. In this design, a tradeoff between fast response and robustness must be taken into account in addition to a guarantee of stability as a switched system. For this purpose, we introduce LMIs with common Lyapunov function to place the closed-loop poles of the observer for each subsystem in the prescribed region in the complex plane. The effectiveness of proposed method is verified through numerical simulations with experimental data set.

Designing an Efficient Multimode Environmental Sensor Based on Graphene–Silicon Heterojunction

By exploiting the adsorbent gaseous molecules induced changes in intrinsic properties of graphene/silicon (Gr/Si) Schottky junction, the authors report a sensitive, low‐power consuming, multimode environmental sensor. By combining an array of Gr/Si Schottky diodes with a differential amplifier circuit, the authors are able to not only differentiate the temperature coefficient and humidity sensing, but also monitor the sun‐light exposure time. Our device is particularly sensitive toward humidity in both forward and reverse biased, and works in resistive as well as capacitive mode. Sensitivity of our devices reached to 17%, 45%, 26%, and 32% per relative humidity (%RH) for reverse biased, forward biased, resistive, and capacitive modes, respectively. In the reverse mode, the power consumption is as low as 2 nW. Moreover, our sensor response is highly selective, with sensitivity lower than 1% for other gases present in atmosphere including H2, O2, N2, and CO2. High sensitivity, low‐power consumption, multiple operation modes, and high selectivity promises application of our sensor for industrial and home safety, environmental monitoring such as indoor and outdoor air conditions, process monitoring, and others.

다중 동작 모드를 가진 PLCopen 표준 호환 모션 응용을 위한 모션 레시피 개념 설계 및 구현

최근 산업 자동화 분야에서는 확장성을 고려한 표준화된 소프트웨어 기반 모션 제어 시스템 개발방법과 다품종 소량 생산을 위한 다양한 동작 모드 지원에 대한 요구가 증대되고 있는 추세이다. 소프트웨어 기반 모션 시스템은 단일 장비 상에서 다양한 동작 모드 전환이 용이하게 하지만 다중 동작 모드를 쉽게 정의하는 도구와 동작 모드 변경에 대한 표준화된 동작 절차가 정의되어 있지 않은 상태에서 다중 동작 모드를 지원하는 모션 제어시스템을 구성하는 것은 쉽지 않다. 본 논문에서는 PLCopen 표준호환 모션 블록들을 이용해 다중 동작 모드를 구성하고 모드 변경을 외부에서 구동하기 위한 프로토콜을 포함하는 모션 레시피 개념을 제안한다. 제안된 모션 레시피 개념은 IEC 61131-3 표준 호환 통합개발환경인 Beremiz의 기능을 확장하여 구현하였으며, 실제 테스트베드 상에서 그 동작을 검증하였다.

A Memory-Based Modular Architecture for SOM and LVQ with Dynamic Configuration

Pattern matching with high computational cost is often realized in hardware by dedicated implementations, having usually low flexibility for satisfying different target applications. The conventional single-instruction-multiple-data (SIMD) solution, which sufficiently exploits the massive intrinsic parallelism, is therefore attracting increasing attention for artificial neural networks. In this paper, as an alternative to SIMD, we propose a memory-based reconfigurable architecture for implementing the self-organizing-map (SOM) neural network model and its supervised variant named learning vector quantization (LVQ). A reconfigurable complete-binary-adder-tree (RCBAT) architecture, which allows multiple operation modes through self-managed dynamic configuration, attains good area/power efficiency due to the reusage of arithmetic units. The implemented pipelined parallelism leads to higher throughput and processing speed. Furthermore, high flexibility in feature-vector dimensionality and number is enabled by a partial vector-component storage (PVCS) concept. The fabricated prototype chips in 65 and 180 nm CMOS technology achieve 51.2 Gbits/s and 9.6 Gbits/s throughput, respectively. The experimental results verify fast training and recognition speed, low power dissipation, and large flexibility for different applications.