The sediments of the Ouaka River were analyzed on the basis of samples taken from the banks during the dry season.These sediments consist of gravel,sand and silt-clay.These sediments are being studied in a context whe...The sediments of the Ouaka River were analyzed on the basis of samples taken from the banks during the dry season.These sediments consist of gravel,sand and silt-clay.These sediments are being studied in a context where the sand from the Ouaka River is going to be used for major construction work on road infrastructure and administrative buildings.In this context,the granulometric analysis of these sediments revealed the dominance of medium sands,silt-clays and,secondarily,coarse sands.The grading curves for these sediments show a sigmoidal“S”shape,indicating that they were deposited in a river and in a depositional environment with relatively high hydrodynamic energy.These sediments,transported and deposited by various hydrodynamic energies,are linked to the massive arrival of materials from secondary watercourses tributary to the Ouaka River.Most of the gravel moves by rolling.Most sand moves by saltation.Silt-clays move essentially by suspension.The Passega diagram describes transport of these gravels by rolling over the bottom.The combined Friedman,Moiola and Weiser diagrams show sediments of fluvial origin and those influenced by sand dunes from the Chad Basin.Analysis of the linear discriminant functions reveals a turbulent fluvial environment with shallow marine beach inputs in turbulent waters.This marine influence is linked to the presence of limestone in the catchment,which is generally formed in a marine palaeoenvironmental context.As part of this study,the distribution of heavy minerals was highlighted in order to determine the origin of sediments from the Ouaka River.These sediments contain mainly tourmaline,rutile,sillimanites,opaque minerals and other heavy minerals.The majority of the sediments are mineralogically immature to sub-mature since the Zircon-Tourmaline-Rutile maturity index is less than 75%.展开更多
Due to the exploding growth in the number of web services, mashup has emerged as a service composition technique to reuse existing services and create new applications with the least amount of effort. Service recommen...Due to the exploding growth in the number of web services, mashup has emerged as a service composition technique to reuse existing services and create new applications with the least amount of effort. Service recommendation is essential to facilitate mashup developers locating desired component services among a large collection of candidates. However, the majority of existing methods utilize service profiles for content matching, not mashup descriptions. This makes them suffer from vocabulary gap and cold-start problem when recommending components for new mashups. In this paper, we propose a two-step approach to generate high-quality service representation from mashup descriptions. The first step employs a linear discriminant function to assign each term with a component service such that a coarse-grained service representation can be derived. In the second step, a novel probabilistic topic model is proposed to extract relevant terms from coarse-grained service representation. Finally, a score function is designed based on the final high-quality representation to determine recommendations. Experiments on a data set from ProgrammableWeb.com show that the proposed model significantly outperforms state-of-the-art methods.展开更多
文摘The sediments of the Ouaka River were analyzed on the basis of samples taken from the banks during the dry season.These sediments consist of gravel,sand and silt-clay.These sediments are being studied in a context where the sand from the Ouaka River is going to be used for major construction work on road infrastructure and administrative buildings.In this context,the granulometric analysis of these sediments revealed the dominance of medium sands,silt-clays and,secondarily,coarse sands.The grading curves for these sediments show a sigmoidal“S”shape,indicating that they were deposited in a river and in a depositional environment with relatively high hydrodynamic energy.These sediments,transported and deposited by various hydrodynamic energies,are linked to the massive arrival of materials from secondary watercourses tributary to the Ouaka River.Most of the gravel moves by rolling.Most sand moves by saltation.Silt-clays move essentially by suspension.The Passega diagram describes transport of these gravels by rolling over the bottom.The combined Friedman,Moiola and Weiser diagrams show sediments of fluvial origin and those influenced by sand dunes from the Chad Basin.Analysis of the linear discriminant functions reveals a turbulent fluvial environment with shallow marine beach inputs in turbulent waters.This marine influence is linked to the presence of limestone in the catchment,which is generally formed in a marine palaeoenvironmental context.As part of this study,the distribution of heavy minerals was highlighted in order to determine the origin of sediments from the Ouaka River.These sediments contain mainly tourmaline,rutile,sillimanites,opaque minerals and other heavy minerals.The majority of the sediments are mineralogically immature to sub-mature since the Zircon-Tourmaline-Rutile maturity index is less than 75%.
基金supported in part by the National Natural Science Foundation of China(No.61673230)
文摘Due to the exploding growth in the number of web services, mashup has emerged as a service composition technique to reuse existing services and create new applications with the least amount of effort. Service recommendation is essential to facilitate mashup developers locating desired component services among a large collection of candidates. However, the majority of existing methods utilize service profiles for content matching, not mashup descriptions. This makes them suffer from vocabulary gap and cold-start problem when recommending components for new mashups. In this paper, we propose a two-step approach to generate high-quality service representation from mashup descriptions. The first step employs a linear discriminant function to assign each term with a component service such that a coarse-grained service representation can be derived. In the second step, a novel probabilistic topic model is proposed to extract relevant terms from coarse-grained service representation. Finally, a score function is designed based on the final high-quality representation to determine recommendations. Experiments on a data set from ProgrammableWeb.com show that the proposed model significantly outperforms state-of-the-art methods.
