Existing fully-automatic transplanters suffer from issues such as low accuracy in conveying and positioning seedling trays, inefficient picking and throwing due to complex movement paths, and seedling damage during the picking process. To address these challenges, this study presents innovative devices for seedling conveying in the X-direction and seedling picking in the Y-direction, considering both row and longitudinal intervals, which simplifies the mechanical structure. Based on these devices, methods were developed to achieve precise seedling positioning in both X and Y directions using multi-sensor combinations and motor control. A Finite State Machine (FSM) model was employed to propose a cooperative method for conveying and picking seedlings, simplifying the execution order and enabling continuous action without dragging or injuring the remaining seedlings. Experimental validation using 72-hole trays demonstrated that positioning deviation increased with motor pulse frequency, with a maximum deviation of 1.35 mm at 800 Hz, which remains within operational requirements. The qualification rate of seedling positioning was 100 % under various transmission speeds. The soil damage ratio (sDR) was measured to evaluate picking success, revealing an average successful seedling extraction rate of 95 %. These research findings offer technical support for efficient coordination between seedling conveying and picking in automatic transplanters.

Recently, the study of soft soil foundation reinforcement using vacuum preloading technology has received widespread attention from scholars. Along with the emergence of numerous joint vacuum preloading treatment methods, the studies on the monitoring of the treatment process are relatively lacking. Therefore, this study adopts the electromechanical impedance (EMI) technique, with piezoelectric smart aggregates affixed to prefabricated vertical drains, to monitor and research the soft soil vacuum preloading treatment process through four sets of model barrel tests. During the tests, the piezoelectric coupling admittance of the structure is measured, and changes in the soil pore water pressure, shear strength, and moisture content are recorded. The analysis demonstrates that as the soil hardened, the resonant frequency of the admittance shifted toward an increasing frequency, and the peak admittance at the resonant frequency decreased. In addition, the degree of shift differs from layer to layer; the more pore water pressure dissipates, the greater the degree of shift. In addition, we calculate the root mean square deviation values from the admittance characteristic curves and fit them with the shear strength and moisture content to obtain function expressions, further confirming the correlation between the vacuum preloading process and admittance characteristics. The experimental results demonstrate that the EMI technique can effectively monitor the vacuum-preloading process.

The Gangjin Celadon Kiln, after its excavation in 1982, was relocated and restored in 1987 and subjected to primary conservation treatment in 2007. However, many problems such as soil disintegration and cavitation occurred in the kiln until recently. In this study, the shape changes due to the conservation treatment in 2020, which was performed to maintain the original shape of the kiln site, were recorded via three-dimensional (3D) scanning, and numerical analysis was conducted to ensure continuous monitoring and preventive conservation. From the results of this study, the locations and ranges of shape changes before and after the conservation treatment of the kiln site were identified through root-mean-square (RMS) deviation analysis and visualization, and the ranges of reinforcement and soil mulch removal were quantified through the deviations at different points. In particular, the most noticeable shape changes occurring from the conservation treatment on the kiln site with 11.2 m long and 16.7 degrees slope were around 15 mm, and many relative changes of 40 mm or more were also observed. In addition, a reinforcement of approximately 40 mm thickness at the least and a flattening were prominently evident on the floor of the working space; the inside of the combustion chamber was visualized with a reinforcement of at least about 50 mm. Damage caused by natural or artificial factors is expected because two extensive conservation treatments were applied in 2007 and 2020 to the kiln sites. Therefore, short-term monitoring using periodic 3D scanning and time-series data comparisons is necessary for the identification of the point of shape change and the determination of major damaged areas so that a mid- to long-term monitoring plan can be established based on the findings of such observations. In addition, predictive modeling research is mandated to detect areas in the entire kiln site that exhibit a greater probability of deterioration based on the available shape change data.

Rainfall can increase the moisture content of a slope, which changes its mechanical properties and thus acts as an important mechanism to trigger landslides. However, it is unclear how moisture contents vary in space and time during rainfall-induced slope movements, and which soil-wetting patterns precede landslide events. Here, we used point sensors and time-lapse 3D electrical resistivity tomography (tl-3D-ERT) technology to monitor the spatiotemporal evolution of the hydrology and movement within a rainfall-induced loess landslide. We observed that movement of the slope involved a semi-continuous process of initiation, acceleration, and deceleration to stabilization. The slope hydrology evolution suggested that initial saturation, dominant flow, and changes in slope recharge and drainage owing to internal seepage and erosion are important factors that affect moisture changes. The movement accelerated when the average saturation value and spatial variation in moisture distribution within the slope increased; however, the movement decelerated when both parameters did not change significantly with time. The accumulation and dissipation of pore water pressure within the slope owing to uneven humidification may be the underlying cause of changes in landslide movement. Our study demonstrates the potential of tl-3D-ERT for monitoring the spatiotemporal variability of moisture evolution within rainfallinduced landslides to determine landslide deformation trends and develop a landslide early warning system.