SPH (smooth particle hydrodynamics) and MoorDyn numerical model were used to investigate systematically the dynamic behavior of moored floating bodies on stepped seabed. Based on the comparison with the experimental data, the influence of wave height and step height on the motion response and mooring force of moored box floating body on stepped seabed was discussed in detail. The results show that the motion response of the two floating bodies increases with the increase of wave height. The mooring power of the other three cables also show an increasing trend except for L3. As the height of the ladder continues to rise, the two floating bodies above and below the seabed ladder appear different change rules. In addition, it is found that the relationship between L2 mooring and L0 and L1 is about 3 times, and the relationship between L2 mooring and L3 is about 2 times.

Under the condition of heavy rainfall, the rock and soil saturation of fully weathered granite slope increases, and the shear strength decreases, which is easy to cause slope instability. In this process, the change of matrix suction is the key factor leading to the change of shear strength. Taking Laoshan fully weathered granite slope in Qingdao as the research object, the soil and water characteristic curve (SWCC) of fully weathered granite based on Van Genuchten model was obtained by means of centrifuge test, undrained direct shear test, X-ray diffraction analysis, conventional silicate chemical total analysis test and scanning electron microscope test. The effect of matrix suction on the shear strength of fully weathered granite was studied systematically. The results show these as follows. The saturation of fully weathered granite soil is negatively correlated with matrix suction, and the soil samples with uneven gradation have stronger drainage capacity. The shear strength index is affected by matrix suction differently. Cohesion is more sensitive to the change of matrix suction than the angle of internal friction. There is a positive correlation between matrix suction and shear strength in fully weathered granite soil. The research results can provide theoretical guidance for slope prevention in fully weathered granite area.

Aiming at the problem of frequent switching due to transient link changes in the heterogeneous network of indoor visible light communication (VLC) and radio frequency (RF) communication, a decision-making mechanism based on spatio-temporal characteristics for VLC/RF networks were proposed. Firstly, in the offline sampling stage, the database was constructed by processing and converting feature data such as spatial location, bandwidth, received signal strength, delay and signal-to-noise ratio of indoor grid points into proportional weights in the controller. Then, in the real-time decision-making phase, the terminal feeded the collected feature data back to the controller to determine the location of the user terminal by comparing it with the information in the database of the controller, and the prioritized link of the current location in the database was extracted and connected. Finally, the link decision model was used to derive the network communication index in real time, and the optimal link was solved by aggregating the proportional weights of the links in the database with the network communication index through the decision function, and the communication quality was improved using the resident timer. Simulation results show that the switching algorithm effectively reduces the average number of switching times and switching interruption probability compared with the traditional fuzzy logic switching algorithm and the vertical switching decision algorithm with equivalent signal-to-noise ratio (SNR). The algorithm can realize intelligent management of indoor heterogeneous networks and improve the quality of user experience.

The background difference method and cross-correlation method used in the extraction of the bullet position in the images collected by the traditional CCD(charge coupled device) intersection stand-up target have the problems of poor versatility and long time-consuming. By analyzing the problems existing in CCD precision target image projectile extraction, a method for CCD precision target image projectile extraction based on IGWO(improved grey wolf optimizer) algorithm was proposed. The DLH (dimensional learning-based hunting) search strategy was used to update the position of each search factor through the neighborhood. Generate candid ate solutions, increase the diversity of search populations, and jump out of local optimal solutions. The bullet extraction problem was transformed into the problem of finding the minimum connected region of gray value under certain constraints. The minimization area gray value model, the vertical light spot area and the low gray area elimination model were established. Under the same parameter setting, the IGWO, GWO(grey wolf optimizer), MFO(moth-flame optimization) algorithm, cross-correlation algorithm, and background difference method were used to conduct comparative experiments. The experimental results show that the target detection success rate of the IGWO algorithm is much higher than other algorithms, reaching 95%, and the algorithm solution time is much lower than other algorithms, shortening to 12 ms.

ARGs(antibiotic resistance genes) as emerging environmental pollutants threaten human health, and studies show that secondary effluent from sewage treatment plants is an important source of ARGs in the environment. Ozone pre-oxidation combined with PAC(powdered activated carbon) and UF(ultrafiltration) was used to treat the secondary effluent from the wastewater treatment plant, and the factors and mechanisms of O₃ dosage, pH, and temperature on the removal of different forms of ARGs in the secondary effluent were investigated. The results show that ARGs could be more effectively removed by PAC adsorption and UF after oxidative inactivation by O₃; under the condition of optimal O₃ dosage (2.0 mg/L), the combined O₃-PAC-UF process could remove different types of ARGs (tetA, tetC, tetG, sulI, sulII) and other pollutants (intⅠ1, 16S rRNA) from the secondary effluent. The removal of different types of ARGs (tetA, tetC, tetG, sulI, sulII) and other pollutants (intⅠ1, 16S rRNA) by the combined process is 10^2.67~10^3.92 copies/mL, and the removal of cellular and free ARGs is significantly enhanced; the elevated pH and lower temperature facilitate the removal of ARGs; the direct oxidation of O₃ molecules dominate the removal of ARGs in the secondary effluent. In conclusion, ozone combined with PAC and UF can effectively remove antibiotic resistance genes from secondary effluent.

To evaluate the safety of navigation flight task scheduling schemes in forest fire rescue, safety evaluation indicators for navigation rescue task scheduling schemes were proposed by detecting the flight path conflicts of various general aircraft. Using an airspace grid model to model the rescue flight environment, and planning the rescue flight paths of aircraft with different performance constraints based on their respective task scheduling schemes, and conducting trajectory conflict detection to evaluate the safety of the task scheduling scheme. The simulation results show that this method has a 53.8% improvement in time efficiency compared to the direct conflict detection algorithm, and a 6.7% improvement in accuracy compared to the efficient spatiotemporal synchronous route conflict detection method. It can be seen that this method can efficiently and accurately predict track conflicts in rescue flights and evaluate the safety of task scheduling schemes, providing effective decision support for navigation rescue command and scheduling work.

A comprehensive joint optimization solution was proposed to address the issue of traditional UAV(unmanned aerial vehicle)-assisted wireless sensor network data collection schemes, where only UAV energy consumption was optimized, while wireless sensor energy consumption is neglected. Firstly, clustering analysis was performed using the K-means algorithm and communication threshold between UAVs and wireless sensors to achieve effective clustering of wireless sensors. Secondly, a multi-objective optimization model was constructed to collaboratively optimize sensor energy consumption and UAV hovering energy consumption. The optimal UAV hovering position and wireless sensor transmission power were determined using a multi-objective particle swarm optimization algorithm. Finally, based on the optimal hovering positions of UAVs in each cluster, an ant colony algorithm was applied to compute the optimal flight path of UAVs, minimizing UAV’s flight energy consumption and thus minimizing the overall energy consumption of the entire data collection system. Simulation results indicate that the proposed solution achieves significant improvements in system energy consumption compared to traditional methods. Specifically, when the clustering radius is 120 meters, sensor energy consumption is reduced by 16.2%, and UAV energy consumption is reduced by 24.9%.

The sigmoid iteration ACO(ant colony algorithm) was optimized for the problems of poor environmental adaptability, high number of inflection points and high computational complexity that exist in the traditional ACO(ant colony algorithm)in route planning. Firstly, the Sigmoid activation function distribution strategy was adopted to improve the initial pheromone spread through the position of the mesh nodes, and the initial concentration of the pheromone was assigned by the sigmoid, which reduced the blindness of the algorithm’s pre-search. Secondly, the adaptive factor was introduced to dynamically regulate the heuristic function, which increased the degree of expectation of the ants in choosing the globally optimal node, and reduces the convergence time of the algorithm. Lastly, a statistical analysis was carried out in each generation of the ant, and the three characteristic parameters of ant path optimal, worst and average were extracted in each generation, and the pheromone updating function was dynamically adjusted according to the number of iterations to give full play to the parallelism characteristics of the algorithm. The results prove that the improved algorithm shortens the optimal path length by 2.7%, 3.2%, and 5.4%, reduces the average number of iterations by 42%, 53%, and 62%, and shortens the worst path length by 49%, 62%, and 73%, respectively, when compared with the ant colony system, the elite ranking algorithm, and the traditional ACO. The study prove that the optimized algorithm has stronger global optimality seeking ability and better application value.

A stepped-frequency radar transmission and reception system based on RF direct sampling technology was designed to address the issues of slow switching speed of sub pulses and incoherent phase of transmission and reception signals in stepped-frequency radar. This system performs RF direct acquisition of C-band radar signals, and all signal processing processes were carried out in the digital domain. It also had high integration and low power consumption. It was generated stepped-frequency signals by fast frequency hopping, frequency sweep of 1.8 GHz bandwidth within 7 ms was gotten. The system operates in the frequency range of 200~2 000 MHz with a frequency step of 2 MHz. At the same time, the parameters of the stepped-frequency signal in this system can be changed according to detection requirements. The test results show that the stepped-frequency radar system can achieve one-dimensional ranging function.

To investigate the impact of polymer polyvinyl alcohol (PVA) and polypropylene fiber on the composite enhancement of loosely piled sandy soil in Southeast Xizang, unconfined compressive strength tests and direct shear tests were conducted. The the effects of the improved sandy soil was understood and the optimal mixing ratio of the improved materials was determined. Additionally, the change in the strength of the improved sandy soil under water erosion after dry and wet cycles was analyzed, and the reinforcement mechanism was investigated. The results demonstrate that the dosage of PVA and polypropylene fibers has a significant effect on the unconfined compressive strength. The best improvement effect is achieved with a dosage ratio of 12% PVA + 0.25% polypropylene fibers, resulting in an unconfined compressive strength of 1 716 kPa. This is 67 times higher than that of sandy soil with an unconfined compressive strength of 25.46 kPa. The shear strength of the improved specimens with different fiber contents increased with the increase of PVA doping. After 10 dry and wet cycling processes, the 12% PVA + 0.25% polypropylene fiber specimen exhibited an unconfined compressive strength of about 748.66 kPa, which was still 91.8% of the strength at 7 days and 1.47 times that of the same age maintenance period of 28 days. Polyvinyl alcohol solution formed a polymer film that adhered to and wrapped the sandy soil, while polypropylene fiber wound and filled the sandy soil. The combination of these two materials improved the stability of the sandy soil, effectively enhancing the bonding strength between soil particles and increasing the compressive strength of the soil body.