A spatiotemporal algebra in Hadoop for moving objects     

Mohamed S. Bakli  Mahmoud A. Sakr  Taysir Hassan A. Soliman 《地球空间信息科学学报》2018,21(2):102-114

Spatiotemporal data represent the real-world objects that move in geographic space over time. The enormous numbers of mobile sensors and location tracking devices continuously produce massive amounts of such data. This leads to the need for scalable spatiotemporal data management systems. Such systems shall be capable of representing spatiotemporal data in persistent storage and in memory. They shall also provide a range of query processing operators that may scale out in a cloud setting. Currently, very few researches have been conducted to meet this requirement. This paper proposes a Hadoop extension with a spatiotemporal algebra. The algebra consists of moving object types added as Hadoop native types, and operators on top of them. The Hadoop file system has been extended to support parameter passing for files that contain spatiotemporal data, and for operators that can be unary or binary. Both the types and operators are accessible for the MapReduce jobs. Such an extension allows users to write Hadoop programs that can perform spatiotemporal analysis. Certain queries may call more than one operator for different jobs and keep these operators running in parallel. This paper describes the design and implementation of this algebra, and evaluates it using a benchmark that is specific to moving object databases.  相似文献   

Reliability of sediment rating curves for a deciduous forest watershed in Iran     

Seyed Hamidreza Sadeghi 《水文科学杂志》2013,58(5):821-831

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Effect of irrigation with olive mill wastewater on soil hydraulic and solute transport properties     

O. Mohawesh  M. Mahmoud  M. Janssen  B. Lennartz 《International Journal of Environmental Science and Technology》2014,11(4):927-934

To evaluate the effect of olive mill wastewater (OMW) application on soil hydraulic and transport properties, two treatment sites, which had been irrigated with OMW for 5 and 15 years, and one control site being irrigated with freshwater were compared. The transport and leaching experiment results showed that a portion of the total soil water was available for transport processes while the remaining of the soil water was considered immobile and not readily accessible for solutes. The separation in water fractions of different mobilities was surprisingly consistent among OMW treatments. The bromide recovery rate decreased with the application of OMW showing that tracer molecules became trapped within immobile water phases. The application of OMW increased significantly the soil water-holding capacity, whereas the soil hydraulic conductivity in the near saturation range decreased significantly with long-term OMW application. The soil irrigated with OMW had significantly higher organic matter content, lower bulk density and relatively higher total porosity, but lower macroporosity than that of control sites. We concluded that the soil was increasingly coated with complex organic molecules originating from OMW, as a result, solute exchange between inter- and intrasoil aggregate water was hindered. Although OMW could cause soil and water pollution, its use in agriculture is promoted because of high nutrients and organic matter contents.  相似文献   

Palynofacies,organic geochemical analyses and hydrocarbon potential of some Upper Jurassic-Lower Cretaceous rocks,the Sabatayn-1 well,Central Yemen     

Abdulwahab S. Alaug  Magdy S. Mahmoud  Amr S. Deaf  Thamer K. AL-Ameri 《Arabian Journal of Geosciences》2014,7(6):2515-2530

The current work investigates the hydrocarbon potentiality of the upper Jurassic–lower Cretaceous rocks in the Marib-Shabwah Basin, Central Yemen, through the Sabatayn-1 well. Therefore, palynological and organic geochemical analyses were carried out on 37 ditch cutting and 12 core samples from the well. Palynofacies analysis of the Madbi (late Oxfordian–early Tithonian) and Nayfa (Berriasian–Valanginian) Formations sediments indicates deposition of their organic-rich shale, calcareous shale and marl in middle to outer shelf environments under dysoxic–anoxic conditions, containing mainly kerogen of types II to III. However, the shales of the lower Sabatayn (Tithonian) Formation were deposited in an inner shelf environment of prevailing dysoxic–suboxic conditions, and show kerogen types III to II. Regional warm and relatively dry palaeoclimate but with local humid conditions developed near the site of the well is thought to have prevailed during deposition of the studied well sediments. The geochemical analyses of the Madbi Formation show higher total organic carbon content (TOC) than the overlying Sabatayn and Nayfa formations: it is varies between 1.2 and 7, and with average 4 wt% TOC, and the obtained S2 values (～3–10, average 7 mg HC/g rock) indicates that the Madbi Formation is mainly good source rock. It shows a good petroleum potential of 4–11 mg HC/g dry rock, and the Rock-Eval pyrolysis indicates mainly kerogen types II to III (oil to gas prone) of hydrogen index values (132–258, and only one sample from Lam Member is of 360 and average 215 mg HC/g TOC). The thermal maturation parameters as T _max (425–440 °C), production index (average 0.13 mg HC/g rock) and thermal alteration index (2 to 2+) reflected that this formation is present at margin of maturation to early mature stage oil window. So, the Lam Member (upper part) of the Madbi Formation is considered the main hydrocarbon (oil and gas) source rock in the Marib-Shabwah Basin. Accordingly, we predict that the Meem Member is an active source for gas and oil accumulations in the overlying sandstone reservoir of the Sabatayn Formation in the Sabatayn-1 well.  相似文献   

Rare earth elements in metarhyolite dyke constraints on processes in a dynamic hydrothermal system,Um Ghannam,South Eastern Desert,Egypt     

R. A. Osman  M. A. M. Mahmoud 《Arabian Journal of Geosciences》2014,7(7):2559-2572

The Um Ghannam area lies within the core of Hafafit Complex, South Eastern Desert. This area is occupied mainly by granitic gneiss (orthogneiss). However, the granitic gneiss is extruded by swarm metarhyolite dykes and quartz veins. The studied metarhyolite dyke is classified into two distinctive zones. However, the intense degree of hydrothermal alteration can partition this dyke into weakly and extremely altered zones. According to the extraordinary diversity in color, this dyke is distinguished into gray to dark gray (weakly altered) and greenish (extremely altered) metarhyolite. Petrographical, mineralogical, and geochemical characteristics of the two distinctive zones are detected in a representative sample. Petrographically, the weakly altered zone is mainly represented by chloritization of primary biotite, garnet, and epidote, and argillitization of primary plagioclase. Although the extremely altered zone contains intensely altered remnants of the original rock, the extremely altered zone is distinguished by intense oxidation products (carbonate minerals and quartz, with significant amounts of secondary Cr-muscovite and hematite). The mineralogical studies are imposed on the millimeter and the micrometer scale in this important hydrogeothermal system. Except for Ca and Mg, most of the major elements are depleted at the extremely altered zone. However, the extremely altered zone is enriched in trace elements (Cr, Mn, Co, and Ni). The major elements of the extremely altered zone reflect the significant alterations (desilication, muscovitization, and carbonatization). These alteration processes have taken place in the hydrogeothermal system in the extremely altered zone. The geothermal fluid is responsible for these hydrothermal alterations. High fO₂ and high temperature are characteristic features of this fluid. Then, the high-field-strength elements such as Zr, Ti, and P are depleted as a significant hydrothermal alteration. Also, nuclear elements with the anion of (CO₃)^2? can travel as molecular complexes (carbonates), as long as the chemical and structural conditions are suitable for the movement of these elements from the metarhyolite dyke to redeposit and accumulate in another geologic formation. The rare earth elements La and Ce, as well as Yb and Lu, are partially mobilized during intensity alterations. The rare earth elements (REEs) are depleted in abundance with enrichment of CO₂ from the weakly altered zone to the extremely altered zone. The REE budget is decreased from the weakly altered zone to the extremely altered zone as 121.17 to (27.38???16.52), respectively. The significant depletion of ∑REEs is controlled by dissolution of monazite. Monazite breakdown and even apatite formation can be caused by alkaline fluid. This fluid is related to event and thermal stage. However, the negative anomaly of Eu can be noticed in all studied samples. Then, Eu anomaly may be formed from plagioclase fractionation. The weakly altered metarhyolite zone and orthogneiss have lower HREE/LREE (0.07–0.11), respectively, relative to the extremely altered metarhyolite zone (0.17???0.2). Even all studied samples at two significant zones are characterized by the enrichment of ∑LREEs relative to ∑HREEs.  相似文献   

Palynostratigraphy and palaeoenvironmental significance of the Cretaceous palynomorphs in the Qattara Rim-1X well,North Western Desert,Egypt     

Maher I. El-Soughier  Amr S. Deaf  Magdy S. Mahmoud 《Arabian Journal of Geosciences》2014,7(8):3051-3068

Palynological and palynofacies analyses were carried out on some Cretaceous samples from the Qattara Rim-1X borehole, north Western Desert, Egypt. The recorded palynoflora enabled the recognition of two informal miospore biozones arranged from oldest to youngest as Elaterosporites klaszii-Afropollis jardinus Assemblage Zone (mid Albian) and Elaterocolpites castelainii–Afropollis kahramanensis Assemblage Zone (late Albian–mid Cenomanian). A poorly fossiliferous but however, datable interval (late Cenomanian–Turonian to ?Campanian–Maastrichtian) representing the uppermost part of the studied section was also recorded. The palynofacies and visual thermal maturation analyses indicate a mature terrestrially derived organic matter (kerogen III) dominates the sediments of the Kharita and Bahariya formations and thus these two formations comprise potential mature gas source rocks. The sediments of the Abu Roash Formation are mostly dominated by mature amorphous organic matter (kerogen II) and the formation is regarded as a potential mature oil source rock in the well. The palynomorphs and palynofacies analyses suggest deposition of the clastics of the Kharita and Bahariya formations (middle Albian and upper Albian–middle Cenomanian) in a marginal marine setting under dysoxic–anoxic conditions. By contrast, the mixed clastic-carbonate sediments of the Abu Roash Formation (upper Cenomanian–Turonian) and the carbonates of the Khoman Formation (?Campanian–Maastrichtian) were mainly deposited in an inner shallow marine setting under prevailing suboxic–anoxic conditions as a result of the late Cenomanian and the Campanian marine transgressions. This environmental change from marginal to open (inner shelf) basins reflects the vertical change in the type of the organic matter and its corresponding hydrocarbon-prone types. A regional warm and semi-arid climate but with a local humid condition developed near/at the site of the well is thought to have prevailed.  相似文献   

Integrated geophysical study to explore the groundwater in the tectonic plain between Wadi El Mahash and Wadi Um Markhah,Southwest Sinai,Egypt     

Adel D. M. Kotb  Galal H. G. Hussein  Mahmoud A. ElHefnawy 《Arabian Journal of Geosciences》2014,7(6):2179-2197

South Sinai Governorate acts as one of the most vital regions in Egypt for its location and natural resources. This governorate has a special economic importance to increase the national income due to its tourism expansion and petroleum. The fresh water is transferred from Cairo through pipelines to cover the demands of local inhabitants in the north Sinai governorate and the capital city of south Sinai governorate. The groundwater exploration and exploitation in this area have a great importance to cover the need of water for the different activities (tourism, petroleum, and agriculture) and to achieve a maximum development in this region. Therefore, the present study deals with using the different geophysical exploration techniques (magnetic, geoelectrical resistivity and shallow refraction seismic) to detect the groundwater aquifer or aquifers in the area between latitudes 27°52′ and 28°05′?N and longitudes 33°55′ and 34°05′?E. in southwestern Sinai—Egypt. The main results of these tools are the maximum depth to the basement surface 180 m and structure elements which affected on this area are represented by a number of normal faults have a trends (NNW–SSE and ENE–WSW) making two grabens isolated by one horst. Tariff Sandstone bed recorded as water-bearing formation and the basement ridge gates in the gulf direction are not capable to pass the ground water from the study area to the Gulf of Suez. Finally, the best locations for drilling groundwater wells were selected from the decision map which generated by using the GIS technique.  相似文献   

Elastic properties of six silicate garnet end members from accurate ab initio simulations   总被引：1，自引：1，他引：0  

Alessandro Erba  Agnes Mahmoud  Roberto Orlando  Roberto Dovesi 《Physics and Chemistry of Minerals》2014,41(2):151-160

The elastic properties of six silicate garnet end members, among the most important rock-forming minerals, are investigated here for the first time via accurate ab initio theoretical simulations. The Crystal program is used, which works within periodic boundary conditions and allows for all-electron basis sets to be adopted. From the computed elastic tensor, Christoffel’s equation is solved along a set of crystallographic directions in order to fully characterize the seismic wave velocity anisotropy in such materials. Polycrystalline isotropic aggregate elastic properties are derived from the computed single-crystal data via the Voigt-Reuss-Hill averaging procedure. Transferability of the elastic properties from end members to their solid solutions with different chemical compositions is also addressed.  相似文献   

Numerical study of power production from tidal energy in the Khuran Channel and its feedback on background hydrodynamics     

Davood Shariatmadari  Seyed Mostafa Siadatmousavi  Cyrus Ershadi 《海洋学报(英文版)》2022,41(5):173-182

This study focuses on the development of a farm of tidal turbines in the Khuran Channel. The important factors include the location of turbines and their hydrodynamic effects on the environment. A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study area. The model is validated by using in situ observations of water level and current data.The appropriate potential points for extracting the tidal e...  相似文献   

Uncertainty of climate change impact on crop characteristics: a case study of Moghan plain in Iran     

Sharafati  Ahmad  Moradi Tayyebi  Mahmoud  Pezeshki  Elnaz  Shahid  Shamsuddin 《Theoretical and Applied Climatology》2022,149(1-2):603-620

Theoretical and Applied Climatology - Crop yield is one of the most critical factors in the food security chain. Climate plays a crucial role in crop water productivity in rainfed and irrigated...  相似文献