The paper reports some methods to select the optimal number of neighbors and to use eigenfeatures for aerial point cloud classification. In the literature, the neighborhood selection is performed using different methods. In this paper, we propose an approach that uses the region growing algorithm. The input data is an aerial point cloud, part of the Romanian Dataset from LAKI II Project. To test our approach, we used a small dataset from the city of Marghita, Bihor County. We report the technical background for classification process and all technical details of the workflow used with insight analyses and comparisons. The work was realized within the VOLTA project (VOLTA, 2017), a RISE Marie-Curie action designed to do research and innovation activities among partners and to exchange knowledge, methods and workflows in the geospatial field.
Private section investment in the construction of transportation infrastructure, one of the most important of which is freeway projects, has been extensively used in developing countries in recent decades. However, in many cases due to the lack of necessary investigations and studies, the criteria have not been properly identified and, as a result, the proper way of participating in large-scale transport projects has resulted in numerous problems and, in some cases, project failure. However, choosing a private-public partnership will have a major impact on the success of freeway construction. However, due to the current conditions of the country’s economy, these projects are following with some risks. Therefore, in this study, the financial risk assessment of “public-private partnership” financing for road construction projects in Iran was investigated using the uncertainty approach and the BAS method. The research population of this study consisted of 23 researchers and experts with Ph.D. degree in finance with minimum degree of associate degree and experience of research and financial consulting in investment firms. According to the results, the lack of stability in planning and implementation of government programs and political risks, increases the risk of road construction projects and, in this regard, controlling the price fluctuations and bank financing of road construction projects can reduce the risk of these projects.
The purpose of this study is to assess the effects of cross-section and slenderness on the dynamic response of high-rise buildings constructed on the coarse soil. In this work, the simulation of the wind and soil effects on the high-rise buildings are done numerically using the ABAQUS software. The wind-induced vibration of the building models is studied through Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD). Co-simulation is accepted for the transfer of loads from the fluid to the structural domain. The mechanical response of the soil system is modeled using direct method. Suitable contact elements for slippage and separation modeling between subsurface elements are also considered. Finally, fluid and structural responses are compared in terms of mean and root mean square values with laboratory results on the wide range of reduced velocities. It is concluded that height and cross-section of building affect the vibrational response of the building, and therefore the designer must carefully consider these factors in order to ensure that the design is safe.
Real water losses derived from water supply systems represent an important topic, nowadays. It is difficult to predict and to calculate the water lost volume, these values being crucial in any water balance. In addition, the leakage flow can be estimated only when the geometric and hydraulic characteristics of the pipes and the period of time associated to the leakage are known. Also, by using the equation of the water flow can be obtained inaccurate values, especially when incorrect values of discharge coefficient are used. The values of the discharge coefficient can vary between 0.6 and 0.85, depending on a multiple aspects, such as the pipe diameter, the orifice size and shape, the pipe material, the orifice position on the pipe wall, the pipe thickness and the hydraulic parameters of the water (flow and pressure). This paper is focused of an experimental study of a leak simulation in a PVC pipe. Thereby, a circular orifice is drilled on PVC pipe wall and the influence of the water flow and pressure on the discharge coefficient (Cd) is analysed. The experimental values obtained for de Cd are 0.59 - 0.86, values that are in accordance with the results from similar studies.
The paper presents the results of experimental investigations and numerical analyses performed on reinforced concrete flat slabs. Two tests were carried out on two flat slab specimens designed without specific shear reinforcement. The present paper deals only with the experimental behaviour and numerical modelling of such slabs, this representing the initial part of a larger study which aims to evaluate the shear capacity of such deficient slabs resulted from faulty design or execution and to identify viable and efficient strengthening solutions. ATENA finite element software package was used to numerically model the behaviour of the specimens. A very good agreement was achieved between the results of experimental investigations and numerical modelling with deviations of 0.2% in terms of maximum load carrying capacity and of 7% in terms of corresponding displacement. The specimens were able to carry loads of more than 950kN, larger than those evaluated using designated Eurocodes, displaying a safety factor of 2.72.
In the last 15 years, mapping technology has become a necessity in smart cities planning. And 2D are starting to be augmented by 3D maps. 3D Maps are already used in the cartographic field, to create a three-dimensional view of the terrain and buildings. In this paper we address the concept of 3D Maps and we compare two methods to generate such maps. In this study two 3D maps were built, one using photogrammetric 3D stereo-restitution and one using automatic extrusion from a LiDAR point cloud and a set of 2D vector polygons. Upon comparison of these maps, we have concluded that the accuracy of the two maps is very similar and it depends very much on the input data and we have observed that creating a precise 3D map in photogrammetric environment takes much longer than the one built using the LiDAR point cloud. As 3D maps become the future of mapping, there is a continuous need for more accurate and complete field data to be collected and processed. Once more detailed field data becomes available, a clear conclusion on which of the methods provide us with a more accurate 3D map could be drawn. The evolution of 3D mapping is rapidly growing together with the applications developed to use it, especially in surveying and material monitoring. The key to future development of smart cities in based on better designs and infrastructures, and 3D mapping technology is a vital instrument to assist such a development.
The fracture network in hydrocarbon reservoirs plays a major role in reservoir fluid transfer to production wells. Modeling of fracture in fractured reservoir is often done randomly. Modelling is based on image logs and core information. Because the information is available in a small number of wells, the model is not reliable and this problem makes it impossible to predict the correct flow rate and the amount of wells produced. In this study, an algorithm based on primary and secondary data for fracture network modelling in one of the southwest fields of Iran has been presented. The initial data include aperture fracture and fracture density, and secondary data includes petrophysical data, i.e. electrical resistance and resistance logs used to scale-up characteristics of fracture in wells. In this study, we tried to increase the accuracy of modelling by using modelling conditionality on existing and constructed data. Gaussian conditional simulation produces a set of realizations on which non-linear statistics can be readily available. In this way, information was entered into the model in areas where fracture was predicted to exist. Using the turning bands co-simulation method in geostatistic, the fracture characteristics were simulated in wells that were not available. Using the results of the 3D model, the fracture of the reservoir was re-constructed. The results showed that the modelling performed in this study has been able to increase the fracture prediction accuracy and their properties in fracture density by about 9% and in the fracture opening by about 5%.
This research concerns about the development and application of Variable Parameter Kinematic Wave Numerical model (VPKWM) based on 1-D Saint-Venant equation, to study the behaviour of the propagation of a flood wave in Non-prismatic natural waterways in an ungauged basin. The channel slope and wetted perimeter are considered as variable because of the irregularity of the boundary of the channel and the change in magnitude of discharge. The scarcity of reliable inflow data at upstream is a serious problem for the flood routing process in an ungauged basin. In this study the inflow hydrograph and lateral inflow hydrographs are obtained using SCS-CN method as rainfall runoff model. The performance of the model assessed considering four parameters such as root mean square error (RMSE), peak discharge, peak time and total volume. The results indicated that the VPKWM for non-prismatic channel provided reasonable output compared with the observed data.
The continuous demands for stringent environmental regulation and increased interests in the preservation of natural resources have motivated industries and research institutions to examine and consider alternative approaches on the use of renewable resources and waste by-products. This study was conducted using one of the most available natural fiber types worldwide, the Phoenix Dactylifera L. Fibers, commonly known as Date Palm Fibers (DPF). Limited researches and inconsistencies in results obtained have been reported in literature on the use of DPF in concrete. Thus, there is a need of further evaluation and study on the structural behavior of fiber reinforced concrete with DPF. The present study used DPF as a natural reinforcement in concrete at varying content of 0%, 0.6%, 1.0%, and 1.4%; and different fiber lengths of 0 mm, 15 mm, 30 mm, and 45 mm. The results indicated that integration of DPF affects the physical properties particularly the workability and density of fresh concrete. Generally, the mechanical properties such as compressive strength, tensile strength, and flexural strength of DPF reinforced concrete decreases as the amount of DPF increases in content and fiber lengths. Scanning Electron Microscopy (SEM) analysis was carried out to examine the internal behavior and effect of DPF in the hardened concrete. Matrix deboning, fiber fractures, and voids due to the pull-out effect were observed as failure modes that contributed to lower compressive strength, tensile strength, flexural strength, and deflection as compared to control specimen.