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Muhammad W.,Pakistan Space and Upper Atmosphere Research Commission | Omer M.,Georgia Institute of Technology
AIAA Infotech at Aerospace Conference and Exhibit 2012 | Year: 2012

Embedded systems used in avionics and spacecraft industry require high degree of confidence in functionality and performance. Traditional simulation based testing methods cannot guarantee the systems behavior under all circumstances. Formal verification is used to verify the functionality of critical embedded system. We present a verification technique based on static formal analysis of data paths in RTL and gate level designs in Verilog and VHDL (HDL descriptions). © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Yao T.,CAS Institute of Tibetan Plateau Research | Thompson L.G.,Ohio State University | Mosbrugger V.,Senckenberg Research Center for Nature Study | Zhang F.,CAS Institute of Tibetan Plateau Research | And 11 more authors.
Environmental Development | Year: 2012

The Tibetan Plateau and surrounding mountains represent one of the largest ice masses of the Earth. The region, referred to by scientists as the Third Pole, covering 5 million km 2 with an average elevation of >4000m and including more than 100,000km 2 of glaciers, is the most sensitive and readily visible indicator of climate change. The area also demonstrates considerable feedbacks to global environmental changes. The unique interactions among the atmosphere, cryosphere, hydrosphere and biosphere on the Third Pole ensure permanent flow of Asia's major rivers, thus significantly influencing social and economic development of China, India, Nepal, Tajikistan, Pakistan, Afghanistan and Bhutan where a fifth of the world's population lives. Like Antarctica and the Arctic, a series of observations and monitoring activities in the Third Pole region have been widely implemented. Yet for a comprehensive understanding of the Third Pole, current observational resources need to be integrated and perfected, and research goals and approaches need to be updated and identified. The Third Pole Environment (TPE) program aims to attract relevant research institutions and academic talents to focus on a theme of 'water-ice-air-ecosystem-human' interactions, to reveal environmental change processes and mechanisms on the Third Pole and their influences on and responses to global changes, and thus to serve for enhancement of human adaptation to the changing environment and realization of human-nature harmony. © 2012. Source

Farhan S.B.,CAS Institute of Tibetan Plateau Research | Farhan S.B.,University of Chinese Academy of Sciences | Farhan S.B.,Pakistan Space and Upper Atmosphere Research Commission | Zhang Y.,CAS Institute of Tibetan Plateau Research | And 6 more authors.
Climate Dynamics | Year: 2015

In a changing climate, river basins with limited summer precipitation but abundant snow and glacier melt-water are affected severely by reductions and seasonal alterations in annual stream flows. However, high altitude glacio-hydrological observations and investigations to address the linkage between the timing of glacier changes and river runoff fluctuations remain ambiguous, particularly in the northwestern Himalayan region of Pakistan. In this context, the hydrological regime of the Astore Basin, a sub-catchment of the Upper Indus River Basin, was comprehensively investigated by employing in situ hydro-meteorological observations in combination with satellite remote sensing data. Two-thirds of the annual precipitation in the Astore Basin falls in winter and spring, mainly deposited by westerly winds, whereas summer and autumn precipitation deposited by the monsoon and local jet streams accounts for only one-third. Some 14 % of the basin area is covered by glaciers and, added to the accumulated seasonal snow deposited by westerly circulations, this can reach 80–85 % of the basin area. Therefore more than 75 % of the annual basin runoff depends on melt-water produced by the predominant seasonal snow and glacier ablation. The non-parametric Mann–Kendall trend test was applied to the whole time-series of hydro-meteorological data. This indicated a lowering of annual and summer mean temperatures during the period 1980–1995 and slight warming during the 1996–2010 period. Similarly, annual, winter and summer precipitation, and annual mean discharge, increased from 1980 to 1995 but, in contrast, a slight decrease in annual and summer precipitation was observed during the 1996–2010 period; however, discharge evidence is slight making any increase in this period insignificant. In addition, the Spearman and Mann–Kendall correlation results depict annual stream flow fluctuations during the 1980–2010 decades in the Astore River that were predominantly influenced by precipitation variations, but not by any alteration in catchment temperatures, and so not governed by enhanced glacier ablation and retreat. The results of the analysis presented here were also substantiated by satellite remote sensing investigation, which points to evidence of stable conditions in the Astore Basin glaciers during this period. © 2014, Springer-Verlag Berlin Heidelberg. Source

Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: ENV.2008. | Award Amount: 7.87M | Year: 2009

The main objective of the EnerGEO project is to develop a strategy for a global assessment of the current and future impact of the exploitation of energy resources on the environment and ecosystems and to demonstrate this strategy for a variety of energy resources worldwide. The global observation strategy will be developed to appropriately assess the impacts of current and future transitions in energy-use on the environment by a combination of: models already available for the different sources of energ: TASES, REMIX and MESSAGE existing global datasets from which environmental indicators will be derived to quantify changes to freshwater systems, biosphere, ecosystems, atmosphere and oceans. existing and currently developed models capable of assessing and forecasting environmental impacts and costs of energy exploitation. By developing a distributed system based on the recommendations of the GEO-Architecture and Data Committee global collection and dissemination of data relating to the effect of energy use on the environment will be supported. By including members of the Energy-Community of Practice of GEO, sustained contribution of the GEO-tasks EN-07-02 and EN-07-3 will be realised. The project takes the testing and demonstration of the observing system and developed scenarios through the execution of dedicated pilots at heart. The pilots are focused on the most important issues relating to atmospheric composition and land degradation through the use of fossil fuels, future impacts of the use and production of biomass on land ecosystems and food security, sustainable integration of solar energy in current grids as well as its visual impact and relating to the impact of wind energy on marine ecosystems. Attention will be given to pollutants that are continuously cycling between the atmosphere and aquatic ecosystems. The results of the pilots feed into an integrated platform that will be run for known scenarios in order to assess energy strategies.

Malik M.J.,University of Twente | Malik M.J.,Pakistan Space and Upper Atmosphere Research Commission | van der Velde R.,University of Twente | Vekerdy Z.,University of Twente | Su Z.,University of Twente
Journal of Hydrometeorology | Year: 2012

This study assesses the impact of assimilating satellite-observed snow albedo on the Noah land surface model (LSM)-simulated fluxes and snow properties. A direct insertion technique is developed to assimilate snow albedo into Noah and is applied to three intensive study areas in North Park (Colorado) that are part of the 2002/03 Cold Land Processes Field Experiment (CLPX). The assimilated snow albedo products are 1) the standard Moderate Resolution Imaging Spectrometer (MODIS) product (MOD10A1) and 2) retrievals from MODIS observations with the recently developed Pattern-Based Semiempirical (PASS) approach. The performance of the Noah simulations, with and without assimilation, is evaluated using the in situ measurements of snow albedo, upward shortwave radiation, and snow depth. The results show that simulations with albedo assimilation agree better with the measurements. However, because of the limited impact of snow albedo updates after subsequent snowfall, the mean (or seasonal) error statistics decrease significantly for only two of the three CLPX sites. Though the simulated snow depth and duration for the snow season benefit fromthe assimilation, the greatest improvements are found in the simulated upward shortwave radiation, with root mean squared errors reduced by about 30%. As such, this study demonstrates that assimilation of satellite-observed snow albedo can improve LSM simulations, which may positively affect the representation of hydrological and surface energy budget processes in runoff and numerical weather prediction models. © 2012 American Meteorological Society. Source

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