Engineering Simulation Platform Research Articles

An Effective Double-Layer Detection System Against Social Engineering Attacks

In recent years, social engineering attacks that use phishing emails as the medium and target specific groups of people have occurred frequently. Current enterprise systems are vulnerable to social engineering attacks. In addition, existing detection methods are relatively ineffective. Therefore, we propose a double-layer detection framework based on deep learning technology. First, a phishing email detection model based on Long Short-Term Memory (LSTM) and extreme gradient boosting tree (XGBoost) is designed from the perspective of individual security. Then, an insider threat detection model based on Bidirectional LSTM and Attention mechanism is designed from the perspective of group security. Finally, combined with the social engineering network attack simulation theory, a social engineering attack and defense simulation platform is established. In the double-layer frame-work, we use Bi-LSTM to obtain long-range dependent features of email body and user sequence information. Then XGBoost and Attention mechanism are used to further strengthen the network structure and improve the classification accuracy. Compared with traditional methods, our model does not require manual feature extraction, and can accurately identify phishing emails and insider threats. Finally, our proposed social engineering simulation platform verifies the effectiveness of the two-layer model. The experimental results show that our proposed framework has the characteristics of timely detection and after-the-fact investigation, which can effectively detect phishing attacks and insider threats faced by enterprise systems.

Response sensitivity studies of a cable-stayed bridge with shape memory alloy damping system considering temperature effects

This paper presents response sensitivity analyses of a cable-stayed bridge equipped with shape memory alloy (SMA) damping devices considering environmental temperature changes. The devices consist of an SMA-based damping brace (SMA-DB) system. An SMA constitutive model is extended to the SMA-DB to consider energy dissipation, rate dependencies, temperature effects, and asymmetry between tension and compression. Based on the direct differentiation method (DDM), an accurate and efficient sensitivity analysis algorithm is derived for the SMA-DB model. The methods of response and response sensitivity analyses are implemented in an open system for earthquake engineering simulation platform, OpenSees, for being used in various problems in civil engineering. A cable-stayed bridge in Shandong Binzhou Yellow River Highway is employed as an application example to verify the newly developed methods. Four SMA-DB components between piers and beams are added to the original finite element bridge model, and the seismic response and response sensitivity analyses are performed to study the complex behaviors of the cable-stayed bridge, e.g., the effect of SMA-DB on the energy dissipation, the changes of responses and response sensitivities due to the temperature change, the relative importance of various parameters on the system responses. The paper provides valuable references for seismic response studies of a cable-stayed bridge with the SMA-DB system.

Seismic performance of bridges with ECC-reinforced piers

Engineered cementitious composite (ECC) material, which is characterized by satisfactory resilience, moderate energy dissipation capacity as well as superhigh compressive and tensile strengths, has been widely applied to civil infrastructures (e.g., bridges, buildings, and coastal structures). To identify sensitive parameters, enhance resilience, and reduce cost of the ECC-reinforced structures effectively, a sensitivity analysis framework for the ECC-reinforced structures is necessary. In this regard, a uniaxial material model for the ECC material is firstly introduced and implemented in an open system for earthquake engineering simulation platform (OpenSees). A sensitivity analysis approach for the ECC material is proposed by deriving a series of sensitivity analysis equations at structure, element, and material levels based on direct differentiation method (DDM). The sensitivity analysis approach is integrated into the OpenSees and could be used directly for the ECC-reinforced structures. At last, the proposed ECC constitutive model are validated by three benchmark examples. The performance assessment and sensitivity analysis are conducted on a prototype bridge. The analyses results indicate that: (1) the earthquake-resistant and damage-control capacities of the ECC material are better than those of the normal concrete; (2) the DDM-based sensitivity analysis method is more efficient and accurate than the FDM-based one.

Seismic Behavior of Superelastic Shape Memory Alloy Spring in Base Isolation System of Multi-Story Steel Frame.

Owing to excellent re-centering capability and good damping behavior, superelastic shape memory alloys (SMAs) are emerging as a potential new material to enhance the seismic resilience of civil structures. This paper focuses on using base isolation with SMA device for isolated structures. SMA springs are deemed to be promising candidate as the damper in the base isolation system, due to the compact form, damping contribution, restoring capability and flexible stiffness. This paper reported the concept of an innovative spring which is made of superelastic SMA wire. Then cyclic loading tests were carried out to evaluate the interested cyclic properties. Parametric analyses based on finite element simulations were conducted to reveal the versatile performance of SMA springs. To further examine its seismic behavior in the base isolation system, the SMA spring was later installed at the isolation level of a multi-story steel frame, based on the finite element model built in the earthquake engineering simulation platform OpenSees. An ordinary elastic spring is included for comparison to highlight the features of SMA springs. Both isolated frames were subjected to real earthquakes. The comparisons indicated that using SMA spring is more effective in controlling maximum and residual deformation for the protected superstructures. Thus, this paper well demonstrated the feasibility and merits of using SMA springs in the isolated frames.

Enabling Cloud-Based Computational Fluid Dynamics With a Platform-as-a-Service Solution

Computational fluid dynamics (CFD) is widely used in manufacturing and engineering from product design to testing. CFD requires intensive computational power and typically needs high-performance computing to reduce potentially long experimentation times. Dedicated high-performance computing systems are often expensive for small-to-medium enterprises (SMEs). Cloud computing claims to enable low-cost access to high-performance computing without the need for capital investment. The cloud-based simulation platform for manufacturing and engineering simulation platform aims to provide a flexible and easy to use cloud-based platform-as-a-service (PaaS) technology that can enable SMEs to realize the benefits of high-performance computing. Our platform incorporates workflow management and multicloud implementation across various cloud resources. Here, we present the components of our technology and experiences in using it to create a cloud-based version of the Transport phenomena Analysis Tool CFD software. Three case studies favourably compare the performance of a local cluster and two different clouds and demonstrate the viability of our cloud-based approach.

Seismic performance-based design and risk analysis of thermal power plant building with consideration of vertical and mass irregularities

Industrial buildings often have irregularities due to operational and complex industrial process. In this paper, a thermal power plant with mass and vertical irregularities was designed with the 2010 ASCE and AISC design codes. Subsequently, a parametric study was undertaken on simplified braced frames to quantify the impact of mass and vertical irregularities, as well as their combined effect. Detailed numerical models were developed in Open System for Earthquake Engineering Simulation platform. With a high seismicity level in China, ground motions were selected and nonlinear time-history analyses were performed. Subsequently, probabilistic seismic demand models, seismic fragilities, and risks were developed for different performance levels. The results show that the vertical irregularity generated larger detrimental effect than mass irregularity, and need more attention in structural design. Collapse risk increased the most due to the combined effect of mass and vertical irregularities. Furthermore, under small earthquake intensities, the thermal power plant with the combined irregularities had higher risk in functional disruption.

A holistic framework for engineering simulation platform development gluing open-source and home-made software resources

The budgetary pressure of engineering simulation platform development is continuing to increase in industry, especially for those scientific institutions, while simulation platform is becoming increasingly important for the researchers in their daily work. Plenty of basic components provided for free by open-source communities can be used to develop simulation platform; however, using open-source components is much more technically difficult than directly utilizing commercial simulation platform. We propose a novel gluing components to tackle the existing difficulties of engineering simulation platform development by using open-source components and home-made resources. In order to reduce the development cost, a holistic framework named TPL.Frame, whose core is the gluing component, is designed to develop engineering simulation platform that consists of SALOME simulation platform, OGRE engine and some other home-made numerical codes. Unlike general commercial simulation solutions, the framework provides not only the basic functionalities, including CAD (Computer-Aided Design) and CAE (Computer-Aided Engineering), but also advanced features, such as real-time 3D visualization, interoperability between FE (Finite Element) method and MB (Multi-Body) dynamics, distributed simulation modeling and other user-defined features. To compare with traditional development method, several cases studied in railway industry are given to demonstrate how to rapidly develop engineering simulation platform using TPL.Frame, thus to prove the effectiveness of the proposed framework.