The capture of a target spacecraft by a chaser is an on-orbit docking operation that requires an accurate, reliable, and robust object recognition algorithm. Vision-based guided spacecraft relative motion during close-proximity maneuvers has been consecutively applied using dynamic modeling as a spacecraft on-orbit service system. This research constructs a vision-based pose estimation model that performs image processing via a deep convolutional neural network. The pose estimation model was constructed by repurposing a modified pretrained GoogLeNet model with the available Unreal Engine 4 rendered dataset of the Soyuz spacecraft. In the implementation, the convolutional neural network learns from the data samples to create correlations between the images and the spacecraft’s six degrees-of-freedom parameters. The experiment has compared an exponential-based loss function and a weighted Euclidean-based loss function. Using the weighted Euclidean-based loss function, the implemented pose estimation model achieved moderately high performance with a position accuracy of 92.53 percent and an error of 1.2 m. The in-attitude prediction accuracy can reach 87.93 percent, and the errors in the three Euler angles do not exceed 7.6 degrees. This research can contribute to spacecraft detection and tracking problems. Although the finished vision-based model is specific to the environment of synthetic dataset, the model could be trained further to address actual docking operations in the future.
In one, docking is defined as “when one incoming spacecraft rendezvous with another spacecraft and flies a controlled collision trajectory in such a manner to align and mesh the interface mechanisms”, and defined docking as an on-orbital service to connect two free-flying man-made space objects. The service should be supported by an accurate, reliable, and robust positioning and orientation (pose) estimation system. Therefore, pose estimation is an essential process in an on-orbit spacecraft docking operation. The position estimation can be obtained by the most well-known cooperative measurement, a Global Positioning System (GPS), while the spacecraft attitude can be measured by an installed Inertial Measurement Unit (IMU). However, these methods are not applicable to non-cooperative targets. Many studies and missions have been performed by focusing on mutually cooperative satellites. However, the demand for non-cooperative satellites may increase in the future. Therefore, determining the attitude of non-cooperative spacecrafts is a challenging technological research problem that can improve spacecraft docking operations. One traditional method, which is based on spacecraft control principles, is to estimate the position and attitude of a spacecraft using the equations of motion, which are a function of time. However, the prediction using a spacecraft equation of motion needs support from the sensor fusion to achieve the highest accuracy of the state estimation algorithm. For non-cooperative spacecraft, a vision-based pose estimator is currently developing for space application with a faster and more powerful computational resource.
คณะเทคโนโลยีการเกษตร
This research aims to evaluate the efficiency of nano-type oxygen diffusers at different pump power levels in sea bass nursery ponds. The study examines how varying power levels affect dissolved oxygen distribution in the water and their impact on the health, growth, and survival rates of sea bass. The findings indicate that pump power levels influence dissolved oxygen concentration, with the optimal power level improving oxygen distribution in the pond. This enhancement leads to higher survival and growth rates for sea bass. The results provide valuable insights for selecting appropriate oxygen diffusers and pump power levels in fish nursery pond systems. The experiment consisted of two conditions: 1. Without fish – This condition assessed the oxygenation capacity, oxygen transfer coefficient, oxygen transfer rate, and oxygen transfer efficiency of pumps at three different power levels. 2. With fish – This condition evaluated whether the oxygen supplied by pumps at three power levels was sufficient, based on the growth rate and survival rate of the fish in the pond. Blood counts were conducted to assess the immune response. The collected data were statistically analyzed using the RCBD method for the condition without fish and the CRD method for the condition with fish, employing SPSS software.
คณะเทคโนโลยีการเกษตร
Soil is home to a diverse array of living organisms that interact within a complex food web, facilitating energy and nutrient cycling essential for sustaining life above ground. Among these organisms, soil microbes play a crucial role in supporting plant growth. Beneficial microorganisms enhance nutrient availability, improve soil structure by increasing porosity, and strengthen plant resistance to diseases. Conversely, harmful microorganisms, such as plant pathogens, can hinder plant growth and reduce crop yields when present in high concentrations. Neutral microorganisms, which naturally inhabit the soil, contribute to the soil ecosystem without directly impacting plants. A single teaspoon of soil contains over a billion microorganisms, yet only about 1% of them can be cultured in laboratory conditions. This highlights soil as one of the richest reservoirs of microbial diversity on Earth.
คณะวิศวกรรมศาสตร์
SecurionSphere is the penetration testing learning platform that focuses on web application exploitation. This platform is intended to address concerns seen in existing penetration testing platforms, such as resource sharing that may affect other users and the constant environment configuration the permits the same response leading to copy the answer from others. Supervisors can use templates to address various forms of web application vulnerability threats. Users can generate the instance of supervisor's templates machine. The platform also randomly generates the environment configuration for each machine has the difference environment and the answer. This allows the users get more realistic learning experiences without affecting the resources of others.