370 research outputs found

    Preliminary study of the Gravimetric Local Geoid Model in Jordan: case study (GeoJordan Model)

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    Recently, there has been an increased interest in studying and defining the Local and Regional Geoid Model worldwide, due to its importance in geodetic and geophysics applications.The use of the Global Positioning System (GPS) is internationally growing, yet the lack of a Geoid Model for Jordan has limited the use of GPS for the geodetic applications in the country. This work aims to present the preliminary results that we propose for «The Gravimetric Jordanian Geoid Model (GeoJordan)». The model is created using gravimetric data and the GRAVSOFT program. The model is validated using GPS and precise level measurements in the Amman area. Moreover, we present a comparison using the Global Geopotential Model OSU91A and the EGM96 Model and the results showed great discrepancies. We also present the approach used to obtain the orthometric height from GPS ellipsoidal height measurements. We found that the error margin obtained in this work of the GeoJordan after fitting the data with GPS/leveling measurements is about (10 cm) in the tested area whereas the standard error of the created model is about (40 cm)

    Adopting US-GAAP Or IASB Accounting Standards By The Arab Countries

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    This paper examines whether Arab countries have adopted the standards issued by the International Accounting Standards Board (lASB) or the US-GAAP.  The results of this study show that companies in the Arab world use different accounting rules and regulations for measurement, recognition, and disclosures of financial position and results of operation.  Consequently, comparability of the financial results of different companies in different countries in the Arab world is impaired.  We recommend adopting financial accounting standards issued by the IASB.  Our study shows that adopting IASB standards has a positive impact on the economic development of the Arab countries

    Empirical Testing Of Different Alternative Proxy Measures For Firm Size

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    This paper examines the relationship among total sales revenue, total assets, book value of equity, and market value of equity for different economic sectors and timeperiods.  Five statistical tools are used to examine the relationship among the different proxies of size of the firm for the period 1999-2002. Our study shows that the relationships among the four measures of the size of the firm are not the same for the different economic sectors and are not stable over time for each economic sector.  Our results suggest that the use of the four measures interchangeably as a proxy for the firm size may not be appropriate

    Sentiment Analysis for e-Payment Service Providers Using Evolutionary eXtreme Gradient Boosting

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    Online services depend primarily on customer feedback and communications. When this kind of input is lacking, the overall approach of the service provider can shift in unintended ways. These services rely on feedback to maintain consumer satisfaction. Online social networks are a rich source of consumer data related to services and products. Well developed methods like sentiment analysis can offer insightful analyses and aid service providers in predicting outcomes based on their reviews—which, in turn, enables decision-makers to develop effective strategic plans. However, gathering this data is more challenging on Arabic online social networks, due to the complexity of the Arabic language and its dialects. In this study, we propose an approach to sentiment analysis that combines a neutrality detector model with eXtreme Gradient Boosting and a genetic algorithm to effectively predict and analyze customers’ opinions of an e-Payment service through an Arabic social network. The proposed approach yields excellent results compared to other approaches. Feature analysis is also conducted on consumer reviews to identify influencing keywords.Deanship of Scientific Research, The University of JordanMinisterio espanol de Economia y Competitividad TIN2017-85727-C4-2-

    Isolation, characterization, and hydrolytic activities of Geobacillus species from Jordanian hot springs

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    The present study was conducted to isolate, identify, characterize and to determine the enzymatic activities of the thermophilic Geobacillus species from five Jordanian hot springs. Based on phenotypic characters, eight thermophilic isolates were identified and belonged to the genus Geobacillus. The Geobacillus isolates were abundant in all investigated hot springs. The optimal temperature for growth of the isolates was 60 to 65°C and the optimal pH was 6 to 8. Colonies were light yellow circular to rhizoid. The bacterial cells were Gram positive rods and endospore forming. All isolates produced amylase, caseinase, alkaline and acid phosphatases, esterase (C4), esterase lipase (C8), α-Galactosidase, ÎČ-Glucuronidase, ÎČ-Glucosidase, and N-Acetyl-ÎČ-glucosaminidase. Seven isolates produced leucine and valine arylamidases and five isolates produced naphthol-AS-B1- phsphohydrolase. Lipase (C14) activity from two isolates and α-chymotrypsin activity from three isolates were also detected. The phenotypic characterization of those isolates was confirmed by genotypic method using 16S rDNA sequence analysis. Maximal homology of all eight  isolates to genus Geobacillus was observed. Five of these isolates showed greater than 98% homology with Geobacillus stearothermophilus and one isolate showed 100% homology with Geobacillus thermoglucosidasius. Therefore, 16S rRNA gene sequence analysis can be considered as a valuable genotypic tool for the identification and characterization of thermophilic bacteria at genus level. Moreover, enzymatic products of those isolates could receive considerable attention due to their potential applications in biotechnology.Keywords: Thermophiles, Geobacillus, hydrolytic enzymes, hot spring, 16S rRNA

    Synthesis of new antenna arrays with arbitrary geometries based on the superformula

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    The synthesis of antenna arrays with low sidelobe levels is needed to enhance the communication systems’ efficiency. In this paper, new arbitrary geometries that improve the ability of the antenna arrays to minimize the sidelobe level, are proposed. We employ the well-known superformula equation in the antenna arrays field by implementing the equation in the general array factor equation. Three metaheuristic optimization algorithms are used to synthesize the antenna arrays and their geometries; antlion optimization (ALO) algorithm, grasshopper optimization algorithm (GOA), and a new hybrid algorithm based on ALO and GOA. All the proposed algorithms are high-performance computational methods, which proved their efficiency for solving different real-world optimization problems. 15 design examples are presented and compared to prove validity with the most general standard geometry: elliptical antenna array (EAA). It is observed that the proposed geometries outperform EAA geometries by 4.5 dB and 10.9 dB in the worst and best scenarios, respectively, which proves the advantage and superiority of our approach

    Study of the factors affecting the karst volume assessment in the Dead Sea sinkhole problem using microgravity field analysis and 3-D modeling

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    Thousands of sinkholes have appeared in the Dead Sea (DS) coastal area in Israel and Jordan during two last decades. The sinkhole development is recently associated with the buried evaporation karst at the depth of 25–50 m from earth's surface caused by the drop of the DS level at the rate of 0.8–1.0 m/yr. Drop in the Dead Sea level has changed hydrogeological conditions in the subsurface and caused surface to collapse. The pre-existing cavern was detected using microgravity mapping in the Nahal Hever South site where seven sinkholes of 1–2 m diameter had been opened. About 5000 gravity stations were observed in the area of 200×200 m<sup>2</sup> by the use of Scintrex CG-3M AutoGrav gravimeter. Besides the conventional set of corrections applied in microgravity investigations, a correction for a strong gravity horizontal gradient (DS Transform Zone negative gravity anomaly influence) was inserted. As a result, residual gravity anomaly of –(0.08Ă·0.14) mGal was revealed. The gravity field analysis was supported by resistivity measurements. We applied the Emigma 7.8 gravity software to create the 3-D physical-geological models of the sinkholes development area. The modeling was confirmed by application of the <i>GSFC</i> program developed especially for 3-D combined gravity-magnetic modeling in complicated environments. Computed numerous gravity models verified an effective applicability of the microgravity technology for detection of karst cavities and estimation of their physical-geological parameters. A volume of the karst was approximately estimated as 35 000 m<sup>3</sup>. The visual analysis of large sinkhole clusters have been forming at the microgravity anomaly site, confirmed the results of microgravity mapping and 3-D modeling

    The optimal synthesis of scanned linear antenna arrays

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    In this paper, symmetric scanned linear antenna arrays are synthesized, in order to minimize the side lobe level of the radiation pattern. The feeding current amplitudes are considered as the optimization parameters. Newly proposed optimization algorithms are presented to achieve our target; Antlion Optimization (ALO) and a new hybrid algorithm. Three different examples are illustrated in this paper; 20, 26 and 30 elements scanned linear antenna array. The obtained results prove the effectiveness and the ability of the proposed algorithms to outperform and compete other algorithms like Symbiotic Organisms Search (SOS) and Firefly Algorithm (FA)
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