Synchronization of Chaotic Neural Networks with Leakage Delay and Mixed Time-Varying Delays via Sampled-Data Control

This paper investigates the synchronization problem for neural networks with leakage delay and both discrete and distributed time-varying delays under sampled-data control. By employing the Lyapunov functional method and using the matrix inequality techniques, a delay-dependent LMIs criterion is given to ensure that the master systems and the slave systems are synchronous. An example with simulations is given to show the effectiveness of the proposed criterion

Patent Data for Engineering Design: A Critical Review and Future Directions

Patent data have long been used for engineering design research because of its large and expanding size, and widely varying massive amount of design information contained in patents. Recent advances in artificial intelligence and data science present unprecedented opportunities to develop data-driven design methods and tools, as well as advance design science, using the patent database. Herein, we survey and categorize the patent-for-design literature based on its contributions to design theories, methods, tools, and strategies, as well as the types of patent data and data-driven methods used in respective studies. Our review highlights promising future research directions in patent data-driven design research and practice.Comment: Accepted by JCIS

The Design of Crowd-Funded Products

Crowdfunding is an emerging phenomenon where entrepreneurs publicize their product concepts to raise development funding and collect design feedback directly from potential supporters. Many innovative products have raised a significant amount of crowdfunding. This paper analyzes the crowd-funded products to develop design guidelines for crowdfunding success. A database of 127 samples is collected in two different product categories from two different crowdfunding websites. They are evaluated using a design project assessment scorecard, the Real-Win-Worth framework, which focuses on the state of maturity on various customer, technical and supply chain dimensions. Our analysis identified key RWW factors that characterize successful design for crowd-funded products. For example, success at crowdfunding is attained through clear explanation of how the design operates technically and meets customer needs. Another recommendation is to not emphasize patent protection, for which crowd-funders are less concerned. Also, evidence of a strong startup financial plan is not necessary for crowdfunding success. These key RWW factors provide guidelines for designers and engineers to improve their design and validate their concepts early to improve their chances for success on crowdfunding platforms.SUTD-MIT International Design Centre (IDC

Salt Freeze-Thaw Damage Characteristics of Concrete based on Computed Tomography

Freeze–thaw damage and salt erosion are important factors that influence the durability of concrete. In this study, degradation laws of concrete in salt freeze–thaw environment were discussed from the microscopic perspective based on the 3D reconstruction of computed tomography images. A damage model based on concrete aggregate volume and porosity was constructed. Furthermore, the main causes of concrete degradation in the salt freeze–thaw environment were analyzed. Results reveal that, with the increase in salt freeze–thaw cycles, the damage of concrete intensifies gradually, and the uniaxial compressive strength declines steadily. Concrete damages have two causes, namely, changes in concrete porosity and variations in concrete aggregate volume. Damages caused by aggregate volume changes are divided into frost heaving and peeling. In accordance with the constructed damage model, the porosity of concrete materials changes slightly, whereas concrete aggregate volume varies significantly. Aggregate volume changes are the main causes of intensified concrete damages and decreased compressive strength. Research conclusions provide theoretical references to disclosing microscopic damage mechanism of concrete in the salt freeze–thaw environment

Evolution of Cooperation among Mobile Agents

We study the effects of mobility on the evolution of cooperation among mobile players, which imitate collective motion of biological flocks and interact with neighbors within a prescribed radius $R$. Adopting the prisoner's dilemma game and the snowdrift game as metaphors, we find that cooperation can be maintained and even enhanced for low velocities and small payoff parameters, when compared with the case that all agents do not move. But such enhancement of cooperation is largely determined by the value of $R$, and for modest values of $R$, there is an optimal value of velocity to induce the maximum cooperation level. Besides, we find that intermediate values of $R$ or initial population densities are most favorable for cooperation, when the velocity is fixed. Depending on the payoff parameters, the system can reach an absorbing state of cooperation when the snowdrift game is played. Our findings may help understanding the relations between individual mobility and cooperative behavior in social systems.Comment: 15 pages, 5 figure

RANS Prediction of Wave-Induced Ship Motions, and Steady Wave Forces and Moments in Regular Waves

The wave-induced motions, and steady wave forces and moments for the oil tanker KVLCC2 in regular head and oblique waves are numerically predicted by using the expanded RANS solver based on OpenFOAM. New modules of wave boundary condition are programed into OpenFOAM for this purpose. In the present consideration, the steady wave forces and moments include not only the contribution of hydrodynamic effects but also the contribution of the inertial effects due to wave-induced ship motions. The computed results show that the contribution of the inertial effects due to heave and pitch in head waves is non-negligible when wave-induced motions are of large amplitude, for example, in long waves. The influence of wave amplitude on added resistance in head waves is also analyzed. The dimensionless added resistance becomes smaller with the increasing wave amplitude, indicating that added resistance is not proportional to the square of wave amplitude. However, wave amplitude seems not to affect the heave and pitch RAOs significantly. The steady wave surge force, sway force and yaw moment for the KVLCC2 with zero speed in oblique waves are computed as well. The present RANS results are compared with available experimental data, and very good agreements are found between them

Stochastic Passivity of Uncertain Neural Networks with Time-Varying Delays

The passivity problem is investigated for a class of stochastic uncertain neural networks with time-varying delay as well as generalized activation functions. By constructing appropriate Lyapunov-Krasovskii functionals, and employing Newton-Leibniz formulation, the free-weighting matrix method, and stochastic analysis technique, a delay-dependent criterion for checking the passivity of the addressed neural networks is established in terms of linear matrix inequalities (LMIs), which can be checked numerically using the effective LMI toolbox in MATLAB. An example with simulation is given to show the effectiveness and less conservatism of the proposed criterion. It is noteworthy that the traditional assumptions on the differentiability of the time-varying delays and the boundedness of its derivative are removed

RANS Prediction of Wave-Induced Ship Motions, and Steady Wave Forces and Moments in Regular Waves

The wave-induced motions, and steady wave forces and moments for the oil tanker KVLCC2 in regular head and oblique waves are numerically predicted by using the expanded RANS solver based on OpenFOAM. New modules of wave boundary condition are programed into OpenFOAM for this purpose. In the present consideration, the steady wave forces and moments include not only the contribution of hydrodynamic effects but also the contribution of the inertial effects due to wave-induced ship motions. The computed results show that the contribution of the inertial effects due to heave and pitch in head waves is non-negligible when wave-induced motions are of large amplitude, for example, in long waves. The influence of wave amplitude on added resistance in head waves is also analyzed. The dimensionless added resistance becomes smaller with the increasing wave amplitude, indicating that added resistance is not proportional to the square of wave amplitude. However, wave amplitude seems not to affect the heave and pitch RAOs significantly. The steady wave surge force, sway force and yaw moment for the KVLCC2 with zero speed in oblique waves are computed as well. The present RANS results are compared with available experimental data, and very good agreements are found between them