Research on path guidance of logistics transport vehicle based on image recognition and image processing in port area

Abstract Due to the messy logistics goods in the port area, some automatic transport vehicles often have errors in cargo transportation due to large path identification errors. Based on this, this study is based on image recognition technology, taking the most common logistics transport vehicles in the port area as the research object and using video image recognition technology as a guiding technology to perform image recognition processing on the ground guidance path. Simultaneously, this study determined the image preprocessing method which is more favorable for visual navigation, used the morphological knowledge of the image to detect the edge of the path image, then determined the position of the path center line, and carried out simulation analysis. The research shows that the results of this study have certain practicality and can provide theoretical references for subsequent related research

A review on evaluation of crack resistance of asphalt mixture by semi-circular bending test

A B S T R A C T: Although there are many kinds of fracture tests to choose from in evaluating the crack resistance of asphalt mixture, the semi-circular bending (SCB) test has attracted a lot of attention in the academic road engineering community because of its simplicity, stability, and flexibility in testing and evaluation. The SCB test has become a common method to study the cracking resistance of asphalt mixture in recent years. This paper mainly summarizes the overview of the SCB test, summarizes some research results and common characterization parameters of the SCB test method in monotone test and fatigue test in recent years, and predicts and suggests the research direction of the SCB test in the future. It is found that the research on the monotonic SCB test is more comprehensive, and the research on the SCB fatigue test needs to be further improved in the aspects of loading mode, characterization parameter selection, and so on. Researchers can flexibly adjust the geometric dimensions and the test parameters of semi-cylindrical specimens, and conduct comprehensive analysis combined with the results of numerical simulation. The crack resistance of asphalt mixture can be comprehensively evaluated by fracture energy, fracture toughness, stiffness, flexibility index and other fracture indicators, combined with the crack propagation of the specimen. The analysis of numerical simulation can confirm the test results. In order to standardize the setting of fatigue parameters for future application, it is necessary to standardize the setting of bending performance

A Drought Index: The Standardized Precipitation Evapotranspiration Irrigation Index

Drought has had an increasingly serious impact on humans with global climate change. The drought index is an important indicator used to understand and assess different types of droughts. At present, many drought indexes do not sufficiently consider human activity factors. This study presents a modified drought index and the standardized precipitation evapotranspiration irrigation index (SPEII), considering the human activity of irrigation that is based on the theory of the standardized precipitation evapotranspiration index (SPEI). This study aims to compare the modified drought index (SPEII) and ·SPEI and self-calibrating Palmer drought severity index (scPDSI) in the major crop-producing areas and use SPEII to evaluate the possible future drought characteristics based on CMIP5 Model. The Pearson correlation coefficient was used to assess the relevance between drought indexes (SPEII, SPEI, and scPDSI) and vegetation dynamics. The normalized difference vegetation index (NDVI) was used to represent the vegetation dynamics change. The results showed that SPEII had better performance than the SPEI and scPDSI in monitoring cropland vegetation drought, especially in cropland areas with high irrigation. The winter wheat growth period of the SPEII had better performance than that of summer maize in croplands with higher irrigation levels on the North China Plain (NCP) and Loess Plateau (LP). In general, future drought on the NCP and LP showed small changes compared with the base period (2001–2007). The drought intensity of the winter wheat growth period showed an increasing and steady trend in 2020–2080 under the representative concentration pathway (RCP) 4.5 scenario on the NCP and LP; additionally, the severe drought frequency in the central LP showed an increasing trend between 2020 and 2059. Therefore, the SPEII can be more suitable for analyzing and evaluating drought conditions in a large area of irrigated cropland and to assess the impacts of climate change on vegetation