Fruit classification is required in many smart-farming and industrial applications. In the supermarket, a fruit classification system may be used to help cashiers and customer to identify the fruit species, origin, ripeness, and prices. Some methods, such as image processing and NIRS (near-infrared spectroscopy) are already used to classify fruit. In this paper, we propose a fast and cost-effective method based on a low-cost Vector Network Analyzer (VNA) device augmented by K-nearest neighbor (KNN) and Neural Network model. S-parameters features are selected, which take into account the information on signal amplitude or phase in the frequency domain, including reflection coefficient S₁₁ and transmission coefficient S₂₁. This approach was experimentally tested for two separate datasets of five types of fruits, including Apple, Avocado, Dragon Fruit, Guava, and Mango, for fruit recognition as well as their level of ripeness. The classification accuracy of the Neural Network model was higher than KNN with 98.75% and 99.75% on the first dataset, whereas the KNN was seen to be more effective in classifying ripeness with 98.4% as compared to 96.6% for neural network.

This study proposes a multifunctional coastal breakwater system that integrates wave attenuation, shoreline protection, and wave energy harvesting to generate renewable electricity for coastal applications. The system is developed for the coastal conditions of Quang Tri Province, Vietnam, where monsoon waves and storms impose large hydrodynamic loads on nearshore structures. Unlike conventional vertical breakwaters, which mainly reflect waves, the proposed system redistributes wave energy into reduced reflection, passive dissipation, and useful mechanical energy absorption. A three-dimensional numerical simulation based on the VOF (Volume of Fluid)) method is used to evaluate wave– structure interaction, pressure distribution, and hydrodynamic loads. The results show that the energy-absorbing breakwater can reduce the reflection coefficient by about 20–30% and wave loads by about 15–25% compared with a conventional breakwater. The absorbed energy is converted into electricity through a hydraulic PTO (Power Take-Off) system and a wave-to-wire architecture using a PMSG (Permanent Magnet Synchronous Generator) generator and an AC– DC–AC circuit. The system shows the potential to form sustainable coastal infrastructure that integrates wave attenuation, load reduction, and renewable power generation.