This paper investigates the sensor-based monitoring feasibility of a bottom-set gillnet through time-domain dynamic simulations for various current and wave conditions and failure scenarios. The dimension and design parameters of the bottom-set gillnet were based on an existing model used in Korea, and the measured environmental data were acquired from the southwest coast of Korea and utilized for the dynamic analysis. For efficient numerical modeling of nets, an equivalent net model which uses fewer line elements was considered, and the projected area, wet weight, and axial stiffness were accordingly adjusted. The hydrodynamic forces on the entire gillnet were estimated using a Morison-force model on the instantaneous positions of the net. The designed gillnet provided excellent stretching performance even under low current velocity. The dynamic responses under wave excitations were not significant in operating conditions; however, significant motions were observed in the fishery-prohibition condition. The proposed monitoring system consisted of an accelerometer, tension sensors, and the global positioning system. Numerous line-failure scenarios were simulated, and the proposed monitoring system could effectively detect a specific problem from the combined patterns of sensor signals by a problem-detection algorithm.

This paper presents the development of a new 6-DOF parallel-kinematic motion simulator. The moving platform is connected to the base by six PUS (Prismatic-Universal-Spherical) serial chains. Comparing with the well-known Stewart-Gough platform-type motion simulator, it uses commercialized linear actuators mounted on the fixed base whereas a 6-UPS manipulator uses telescopic linear ones. Therefore, the proposed motion simulator has the advantages of lower inertia and easier fabrication over a 6-UPS counterpart. The inverse position, Jacobian and workspace analyses are performed. Using inclined arrangement of universal joints, the workspace is greatly increased. The prototype motion simulator and real-time controller using xPC have been developed. Basic six-axis motion test with the ride of single operator has been successfully performed.

Integrity monitoring of slender gillnets designed for the open sea is essential for reliable management and quick collection to prevent loss. We proposed a method for detecting damage and theft to a gillnet based on sensor fusion and the Artificial Neural Network (ANN) model. Time-domain numerical simulations of a slender gillnet were performed. Equivalent net models with the