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Alkazemi B.Y.,University of Umm Al - Qura | Almajnooni S.M.,Presidency of Meteorology and Environment
Proceedings of the 6th IASTED International Conference on Advances in Computer Science and Engineering, ACSE 2010 | Year: 2010

Software component re-use is of obvious importance to the software engineering process, and is increasing in prominence due to the highly successful open-source software movement. While open-source software is, by its very nature, available for re-use, facilities for finding components that fits an engineer's needs are somewhat limited. Repositories for open-source software are available on the world-wide web, and work well if you know what you are looking for. However, such repositories are more problematical for unstructured searching or browsing, or for assisting in the re-use of part of an open-source software system that has been deposited in the repository. This paper proposes a prototype of repository for open-source software that incorporates a software component classification scheme, together with re-factoring mechanisms that can deliver reusable software components from deposited software systems. The design consideration of this prototype is to tackle some of the problems in the current open-source repositories in order to further promote the identification and re-use of software. Source

Al Zawad F.M.,Presidency of Meteorology and Environment | Aksakal A.,King Fahd University of Petroleum and Minerals
Green Energy and Technology | Year: 2010

Climate change issues are discussed widely around the world. Many scientists (Treut et al., 2007) relate global warming and its consequences to human activities and not to natural fluctuations. The reasoning of this approach is the timescale of climate change. Recent warming of the Earth is considered to be abrupt compared to the timescale usually accompanied with natural climate change episodes. Earth's natural climate changes happen gradually in a long period of time (tens of thousands to millions of years), but we are witnessing an abrupt change over the past 200 years. The industrial revolution with fossil fuels as its main source of energy is setting a steady emission increase of carbon dioxide and other greenhouse gases which trap heat causing an increase of temperature in the lower atmosphere. Source

Zhang Y.,U.S. National Center for Atmospheric Research | Liu Y.,U.S. National Center for Atmospheric Research | Kucera P.A.,U.S. National Center for Atmospheric Research | Alharbi B.H.,King Abdulaziz City for Science and Technology | And 2 more authors.
Atmospheric Environment | Year: 2015

This paper documents the performance of the fully coupled WRF-Chem model at 21.6 km and 7.2 km resolution over Saudi Arabia in simulating a severe dust storm event that occurred in March 2009. The comparisons between the model simulations and the observed AOD at the Solar Village AERONET site and the MODIS measurements show that WRF-Chem satisfactorily resolves the arrival, evolution and spatial distributions of the dust storm over Saudi Arabia especially for the fine domain at 7.2 km resolution. The model simulated surface meteorological variables at Riyadh Airport, Hafr Al-Batin Airport, Dammam Airport and Gassim Airport follow the observations in terms of magnitude and temporal evolution although model biases such as deficiencies in simulating the amplitude of diurnal cycles are noted. Higher resolution and shorter initialization time improve the model performance in aerosol optical depth but for surface variables shorter initialization time improves correlation while higher horizontal resolution improves mean biases to some extent. The simulated dust plume is mainly confined between the surface and the 5-km height, with the peak concentrations located in the lowest 500 m. The vertical extent of the dust plume shows gradual decreases during the simulation period when averaged over the entire fine domain and an area centered around Solar Village, and also varies in accordance with the development and decay of the boundary layer. © 2015 Elsevier Ltd. Source

Butenhoff C.L.,Portland State University | Khalil M.A.K.,Portland State University | Khalil M.A.K.,King Abdulaziz University | Porter W.C.,Portland State University | And 4 more authors.
Journal of the Air and Waste Management Association | Year: 2015

This paper presents a one-year record of in situ air-quality data from nine sites throughout Saudi Arabia. The data set is composed of hourly measurements of ozone (O3), nitrogen dioxide (NO2), and carbon monoxide (CO) at six of the largest cities in Saudi Arabia (Riyadh, Jeddah, Makkah, Yanbu, Dammam, Hafouf) and two remote locations in the mountainous southwestern region of Alsodah for the year 2007. The authors found that international O3and CO standards were routinely exceeded throughout the year at many sites, and that exceedances increased during Ramadan (Sep. 12 – Oct. 13), the Islamic month of fasting when much of normal daily activity is shifted to nighttime hours. In general NO2 and CO levels were higher in Saudi cities compared to U.S. cities of comparable population, while O3levels were lower. There was a general trend for O3 and NO2 to be negatively correlated in Saudi cities in contrast to U.S. cities where the correlation is positive, suggesting that ozone chemistry in Saudi Arabia is limited by volatile organic compound emissions. This may be caused by low biogenic emissions from vegetation. Pollutant levels were lower at most Saudi sites during the four day Hajj period (Dec. 18–21) but higher in Makkah which receives millions of visitors during Hajj. The authors also found that ozone levels were elevated during the weekend (Thursday & Friday) relative to weekday levels despite lower NO2, a phenomenon known as the “weekend effect.” As little air quality data is available from Saudi Arabia in the English-language literature, this data set fills a knowledge gap and improves understanding of air quality in an important but under-reported region of the world. © 2015 A&WMA. Source

Khalil M.A.K.,Portland State University | Khalil M.A.K.,King Abdulaziz University | Butenhoff C.L.,Portland State University | Porter W.C.,Portland State University | And 4 more authors.
Journal of the Air and Waste Management Association | Year: 2016

Yanbu, on the Red Sea, is an affluent Saudi Arabian industrial city of modest size. Substantial effort has been spent to balance environmental quality, especially air pollution, and industrial development. We have analyzed six years of observations of criteria pollutants O3, SO2, particles (PM2.5 and PM10) and the known ozone precursors—volatile organic compounds (VOCs) and nitrogen oxides (NOx). The results suggest frequent VOC-limited conditions in which ozone concentrations increase with decreasing NOx and with increasing VOCs when NOx is plentiful. For the remaining circumstances ozone has a complex non-linear relationship with the VOCs. The interactions between these factors at Yanbu cause measurable impacts on air pollution including the weekend effect in which ozone concentrations stay the same or even increase despite significantly lower emissions of the precursors on the weekends. Air pollution was lower during the Eids (al-Fitr and al-Adha), Ramadan and the Hajj periods. During Ramadan, there were substantial night time emissions as the cycle everyday living is almost reversed between night and day. The exceedances of air pollution standards were evaluated using criteria from the U.S. Environmental Protection Agency (EPA), World Health Organization (WHO), the Saudi Presidency of Meteorology and Environment (PME) and the Royal Commission Environmental Regulations (RCER). The latter are stricter standards set just for Yanbu and Jubail. For the fine particles (PM2.5), an analysis of the winds showed a major impact from desert dust. This effect had to be taken into account but still left many occasions when standards were exceeded. Fewer exceedances were found for SO2, and fewer still for ozone. The paper presents a comprehensive view of air quality at this isolated desert urban environment. Implications: Frequent VOC-limited conditions are found at Yanbu in Saudi Arabia that increase ozone pollution if NOx is are reduced. In this desert environment, increased nightlife produces the highest levels of VOCs and NOx at night rather than the day. The effects increase during Ramadan. Fine particles peak twice a day—the morning peak is caused by traffic and increases with decreasing wind, potentially representing health concerns, but the larger afternoon peak is caused by the wind, and it increases with increasing wind speeds. These features suggest that exposure to pollutants must be redefined for such an environment. © 2016 A&WMA. Source

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