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E-commerce emerged as consequence of electronic transactions developed on 60’s, but real boom was observed during 90’s along with Internet common use. Complexity sciences approach has several advantages for e-Commerce study. This study addresses the need for modelling and simulation (M&S) of e-commerce supply chain as complex adaptive system (CAS) but with a novel application in the field of hybrid M&S, integrating top-down and bottom-up approaches using synthetic microanalysis, to perform simulation experiments to find natural emergent properties at certain levels as result of the interactions between the constituent parts, so far lacking in the scientific literature. Although previous researchers conducted simulation studies into the e-commerce supply chain as CAS, they all focused on applying agent-based simulation approach only. First, we conduct the literature review on main features of CAS, M&S of CAS as well as the e-commerce supply chain conceptualized as CAS and their modelling and simulation evolution. Second, we present a novel hybrid M&S methodology for integrating top-down and bottom-up approaches using synthetic microanalysis. Then, we applied the methodology to an omnichannel retail business case study. Finally, our concluding remark and future work are drawn. The novel methodology proved to be useful for anticipate business decisions on e-commerce supply chain.

Two‐dimensional (2‐D) hybrid model is developed to investigate the second harmonic (SH) generation of electromagnetic ion cyclotron (EMIC) waves. Applying the singular value decomposition method to simulated fields, we show that the SH exhibits wave properties analogous to typical EMIC waves generated by ion cyclotron instabilities, that is, left‐hand polarization and small wave normal angle. However, the bicoherence index inferred from simulated fields reflects a strong phase coupling between the fundamental wave (FW) and the SH, illustrating the nonlinear generation of the SH by the FW. The necessary conditions, especially for the wave vector relation, are further verified from a 2‐D perspective. The simulated amplitude ratios well meet the theoretical results only in the SH saturation stage, while the necessary conditions remain satisfied almost throughout the simulation. This study provides a comprehensive analysis of the SH excitation in a 2‐D simulation domain, contributing to a deeper understanding of EMIC wave nonlinear generation. Plain Language Summary Recent studies have unveiled the generation of nonlinear second harmonics (SH) of electromagnetic ion cyclotron (EMIC) waves. The SH is nonlinearly driven by the fundamental wave (FW) and satisfies the necessary conditions: ω2 = 2ω1 and k2 = 2k1, where ω1 (ω2) and k1 (k2) are the frequency and the wave vector of the FW (SH), respectively. Previous studies have relied on one‐dimensional (1‐D) hybrid simulations to investigate the SH. However, 1‐D simulations allow waves to propagate along a single dimension and lack spatial variation of the field orthogonal to this dimension, which impedes the complete verification of the relation k2//k1. Thus, in this study, the SH generation is modeled by two‐dimensional (2‐D) hybrid codes. The simulated SH exhibits characteristics similar to typical EMIC waves with left‐hand polarization and small wave normal angle. The bicoherence index is utilized to reveal the phase coupling between the SH and FW. The necessary conditions, especially for the wave vector relation, are verified from a 2‐D perspective for the first time. Additionally, the amplitude ratios of the SH to the FW and their phase velocities are compared with theoretical results. The comprehensive analyses of this study provide substantial evidence for the SH generation mechanism. Key Points Two‐dimensional (2‐D) hybrid codes are developed to model the nonlinear second‐harmonic (SH) generation of electromagnetic ion cyclotron waves The necessary conditions required by the SH generation mechanism are verified from a 2‐D perspective The theoretical amplitude ratios between harmonics are only satisfied in the SH saturation stage

Hybrid simulation can be a cost effective approach for dynamic testing of structural components at full scale while capturing the system level response through interactions with a numerical model. The dynamic response of a seismically isolated structure depends on the combined characteristics of the ground motion, bearings, and superstructure. Therefore, dynamic full-scale system level tests of isolated structures under realistic dynamic loading conditions are desirable towards a holistic validation of this earthquake protection strategy. Moreover, bearing properties and their ultimate behavior have been shown to be highly dependent on rate-of-loading and scale size effects, especially under extreme loading conditions. Few laboratory facilities can test full-scale seismic isolation bearings under prescribed displacement and/or loading protocols. The adaptation of a full-scale bearing test machine for the implementation of real-time hybrid simulation is presented here with a focus on the challenges encountered in attaining reliable simulation results for large scale dynamic tests. These advanced real-time hybrid simulations of large and complex hybrid models with several thousands of degrees of freedom are some of the first to use high performance parallel computing to rapidly execute the numerical analyses. Challenges in the experimental setup included measured forces contaminated by delay and other systematic control errors in applying desired displacements. Friction and inertial forces generated by the large-scale loading apparatus can affect the accuracy of measured force feedbacks. Reliable results from real-time hybrid simulation requires implementation of compensation algorithms and correction of these various sources of errors. Overall, this research program confirms that real-time hybrid simulation is a viable testing method to experimentally assess the behavior of full-scale isolators while capturing interactions with the numerical models of the superstructure to evaluate system level and in-structure response.

Summary As a low cost and maintenance energy‐absorbing device, tuned liquid damper (TLD) is being widely used to suppress structural vibration. In this paper, the real‐time hybrid simulation (RTHS) is employed to investigate the performance of TLD for controlling seismic responses of actual multi‐story structures, where the TLD is experimentally modeled as physical substructure and the multi‐story structure is numerically simulated as numerical substructure. Taking advantage of RTHS technique, a methodology for achieving full‐scale TLD experiments is developed through suitable similarity design; a new interaction force measurement method and a new dual explicit algorithm are embedded into RTHS system to enhance simulation capability. First, the seismic response of a two‐story structure installed with TLD is analyzed by applying RTHS. Correspondingly, the pure shaking table test is performed to assess the accuracy of the RTHS. Then, the effectiveness of TLD for structures with various numbers of floors and different structural properties is tested through RTHS by varying the simulation model of the numerical substructure. Finally, the effects of mass ratio and structural damping ratio on a given TLD‐structure system are investigated. Copyright © 2015 John Wiley & Sons, Ltd.

Summary Interstory isolation systems have recently gained popularity as an alternative for seismic protection, especially in densely populated areas. In inter‐story isolation, the isolation system is incorporated between stories instead of the base of the structure. Installing inter‐story isolation is simple, inexpensive, and disruption free in retrofit applications. Benefits include nominally independent structural systems where the accelerations of the added floors are reduced when compared to a conventional structural system. Furthermore, the base shear demand on the total structure is not significantly increased. Practical applications of inter‐story isolation have appeared in the United States, Japan, and China, and likewise new design validation techniques are needed to parallel growing interest. Real‐time hybrid simulation (RTHS) offers an alternative to investigate the performance of buildings with inter‐story isolation. Shake tables, standard equipment in many laboratories, are capable of providing the interface boundary conditions necessary for this application of RTHS. The substructure below the isolation layer can be simulated numerically while the superstructure above the isolation layer can be tested experimentally. This configuration provides a high‐fidelity representation of the nonlinearities in the isolation layer, including any supplemental damping devices. This research investigates the seismic performance of a 14‐story building with inter‐story isolation. A model‐based acceleration‐tracking approach is adopted to control the shake table, exhibiting good offline and online acceleration tracking performance. The proposed methods demonstrate that RTHS is an accurate and reliable means to investigate buildings with inter‐story isolation, including new configurations and supplemental control approaches.

To meet rising demands in performance and emissions compliance, companies are driven to develop systems of ever-increasing complexity. In-the-loop methods use a hybrid approach combining a physical subsystem with a virtual subsystem in real-time that can make product development processes faster and cheaper, enabling physical subsystems to be tested in real-world conditions while they are immersed in virtual environment simulation. These techniques evolved from being used solely in controller development with only the embedded controller placed as hardware-in-the-loop (HIL), to being a more holistic technique for system synthesis, capable of both component- and system-level studies. This paper delves into the development of the latter form, henceforth referred to as ‘component-in-the-loop’ or CIL. It provides a literature review of the growing uses of the technique in automotive development, giving a general implementation guidance in system architecture, methodology and control system structure. Furthermore, it suggests the need to clarify terminologies related to in-the-loop methods for a more efficient taxonomy. Definitions are proposed where deemed appropriate. In the age of search engines, this should facilitate knowledge transfer within and across disciplines. Finally, it highlights the key challenges in constructing such systems while discussing attempted solutions. CIL has reached a state of maturity where it is ready for wider adoption and continued technological progress will only push its potential further.

Summary The use of tuned liquid dampers (TLDs) is an effective passive control technique to suppress structural vibration under wind and seismic loads. This paper investigates the size effect of TLDs on control efficiency. Given the advantages of real‐time hybrid simulation, two issues affecting the control performance of TLD are addressed: (a) the geometric size and (b) the experimental model scale. A series of real‐time hybrid simulations is performed, in which TLD devices with various sizes (including full‐scale and small‐scale) are experimentally modeled as physical substructures; the controlled structures are numerically simulated as numerical substructures. Results demonstrate that TLD performance is size dependent; a shallow liquid in TLD with lower relative liquid depth may be more efficient for both peak and root‐mean‐square response control. Scaled TLD models that are usually used in conventional shaking table tests generally overestimate the control performance of prototype TLD devices, indicating that full‐scale TLD experiments should be pursued to ensure proper performance evaluation.

SUMMARY Small‐scale models have been commonly utilized in testing of performance of active mass driver (AMD) control systems. The utmost reason is that physical testing of AMD system at full scale is usually too expensive to afford, as well as hard to implement on site. With reference to the real‐time hybrid simulation technology, a real‐time AMD subsystem testing method is proposed in this paper. In this method, the entire system is composed of AMD as physical subsystem and target structure as numerical subsystem. The physical test is conducted on AMD subsystem, whereas the numerical simulation is carried out on the structure subsystem. Meanwhile, the real‐time data are being communicated between these two subsystems. This method is then applied to the performance validation of a novel AMD control system, which is driven by a linear motor. In the test, a benchmark three‐storey frame structure is employed as the numerical subsystem, and earthquake excitations are used as the external input. On the basis of a series of tests, both the time history and the statistical criteria show that the results of AMD subsystem and structure subsystem obtained in the real‐time AMD subsystem test agree well with the simulation results. Furthermore, all the test results show good repeatability. Therefore, the feasibility and reliability of the proposed real‐time AMD subsystem testing approach for performance validation of AMD subsystem has been demonstrated. Such kind of experimental method is efficient in terms of reducing cost associated with performance validation of large‐scale active control systems prior to the implementation. Copyright © 2013 John Wiley & Sons, Ltd.

Dependability assessment is one of the most important activities for the analysis of complex systems. Classical analysis techniques of safety, risk, and dependability, like Fault Tree Analysis or Reliability Block Diagrams, are easy to implement, but they estimate inaccurate dependability results due to their simplified hypotheses that assume the components’ malfunctions to be independent from each other and from the system working conditions. Recent contributions within the umbrella of Dynamic Probabilistic Risk Assessment have shown the potential to improve the accuracy of classical dependability analysis methods. Among them, Stochastic Hybrid Fault Tree Automaton (SHyFTA) is a promising methodology because it can combine a Dynamic Fault Tree model with the physics-based deterministic model of a system process, and it can generate dependability metrics along with performance indicators of the physical variables. This paper presents the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO), a Matlab® software library for the modelling and the resolution of a SHyFTA model. One of the novel features discussed in this contribution is the ease of coupling with a Matlab® Simulink model that facilitates the design of complex system dynamics. To demonstrate the utilization of this software library and the augmented capability of generating further dependability indicators, three different case studies are discussed and solved with a thorough description for the implementation of the corresponding SHyFTA models.