به نام خدا
Title: Mission Assurance Increased with Regression Testing
Authors: Roland Lang
Abstract: Knowing what to test is an important attribute in any testing campaign, especially when it has to be right or the mission could be in jeopardy. The New Horizons mission, developed and operated by the John Hopkins University Applied Physics Laboratory, received a planned major upgrade to their Mission Operations and Control (MOC) ground system architecture. Early in the mission planning it was recognized that the ground system platform would require an upgrade to assure continued support of technology used for spacecraft operations. With the planned update to the six year operational ground architecture from Solaris 8 to Solaris 10, it was critical that the new architecture maintain critical operations and control functions. The New Horizons spacecraft is heading to its historic rendezvous with Pluto in July 2015 and then proceeding into the Kuiper Belt. This paper discusses the Independent Software Acceptance Testing (ISAT) Regression test campaign that played a critical role to assure the continued success of the New Horizons mission. The New Horizons ISAT process was designed to assure all the requirements were being met for the ground software functions developed to support the mission objectives. The ISAT team developed a test plan with a series of test case designs. The test objectives were to verify that the software developed from the requirements functioned as expected in the operational environment. As the test cases were developed and executed, a regression test suite was identified at the functional level. This regression test suite would serve as a crucial resource in assuring the operational system continued to function as required with such a large scale change being introduced. Some of the New Horizons ground software changes required modifications to the most critical functions of the operational software. Of particular concern was the new MOC architecture (Solaris 10) is Intel based and little end ian, and the legacy architecture (Solaris 8) was SPARC based and big end ian. The presence of byte swap issues that might not have been identified in the required software changes was very real and can be difficult to find. The ability to have test designs that would exercise all major functions and operations was invaluable to assure that critical operations and tools would operate as they had since first operational use. With the longevity of the mission also came the realization that the original ISAT team would not be the people working on the ISAT regression testing. The ability to have access to all original test designs and test results identified in the regression test suite greatly improved the ability to identify not only the expected system behavior, but also the actual behavior with the old architecture.
Publish Year: 2013
Published in: Aerospace - IEEE
Number of Pages: 8
موضوع: مهندسی نرم افزار، تست نرم افزار، تست مجتمع سازی
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Numerical simulation and optimization of CO2 sequestration in saline aquifers
Authors: Zheming Zhang, Ramesh Agarwal
Abstract: With heightened concerns on CO2 emissions from coal fired electricity generation plants, there has been major emphasis in recent years on the development of safe and economical Carbon Dioxide Capture and Sequestration (CCS) technology worldwide. Saline reservoirs are attractive geological sites for CO2 sequestration because of their huge capacity for long term sequestration. Over the last decade, numerical simulation codes have been developed in US, Europe and Japan to determine a priori the CO2 storage capacity of a saline aquifer and to provide risk assessment with reasonable confidence before the actual deployment of CO2 sequestration can proceed with enormous investment. In US, the 2nd version of Transport of Unsaturated Groundwater and Heat (TOUGH2) numerical simulator has been widely used for this purpose. However at present, it does not have the ability to determine optimal parameters such as injection rate, injection pressure, injection depth for vertical and horizontal wells, etc. for optimization of the CO2 storage capacity and for minimizing the leakage potential by confining the plume migration. This paper describes the development of a “Genetic Algorithm (GA)” based optimizer for TOUGH2 that can be used by the industry with good confidence to optimize the CO2 storage capacity in a saline aquifer of interest. This new code including the TOUGH2 and the GA optimizer is designated as “GATOUGH2”. It has been validated by conducting simulations of three widely used benchmark problems by the CCS researchers worldwide: (a) study of CO2 plume evolution and leakage through an abandoned well, (b) study of enhanced CH4 recovery in combination with CO2 storage in depleted gas reservoirs, and (c) study of CO2 injection into a heterogeneous geological formation. The results of these simulations are in excellent agreement with those of other researchers using different codes. The validated code has been employed to optimize the proposed water-alternating-gas (WAG) injection scheme for (a) a vertical CO2 injection well and (b) a horizontal CO2 injection well, in order to optimize the CO2 sequestration capacity of an aquifer. The optimized calculations from GATOUGH2 are compared with the brute force nearly optimized results obtained by performing a large number of calculations. These comparisons demonstrate the significant efficiency and accuracy of GATOUGH2 as an optimizer compared to using TOUGH2 in a brute force manner. This capability holds a great promise in studying a host of other problems in CO2 sequestration such as how to optimally accelerate the capillary trapping, accelerate the dissolution of CO2 in water or brine, and immobilize the CO2 plume.
Publish Year: 2013
Published in: Computers and Fluids - Science Direct
Number of Pages: 9
موضوع: مهندسی مواد، متالورژی
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Path Planning and Ground Control Station Simulator for UAV
Authors: Alain AJAMI, JeanFrancois BALMAT, JeanPaul GAUTHIER, Thibault MAILLOT
Abstract: In this paper we present a Universal and Interoper-able Ground Control Station (UIGCS) simulator for fixed androtary wing Unmanned Aerial Vehicles (UAVs), and all types ofpayloads. One of the major constraints is to operate and man-age multiple legacy and future UAVs, taking into account thecompliance with NATO Combined/Joint Services OperationalEnvironment (STANAG 4586). Another purpose of the station isto assign the UAV a certain degree of autonomy, via autonomousplanification/replanification strategies. The paper is organizedas follows.In Section 2, we describe the non-linear models of the fixed androtary wing UAVs that we use in the simulator.In Section 3, we describe the simulator architecture, which isbased upon interacting modules programmed independently.This simulator is linked with an open source flight simulator, tosimulate the video flow and the moving target in 3D. To concludethis part, we tackle briefly the problem of the Matlab/Simulinksoftware connection (used to model the UAV_s dynamic) with thesimulation of the virtual environment.Section 5 deals with the control module of a flight path of theUAV. The control system is divided into four distinct hierarchicallayers: flight path, navigation controller, autopilot and flightcontrol surfaces controller.In the Section 6, we focus on the trajectory planifica-tion/replanification question for fixed wing UAV. Indeed, one ofthe goals of this work is to increase the autonomy of the UAV. Wepropose two types of algorithms, based upon 1) the methods ofthe tangent and 2) an original Lyapunov-type method. Thesealgorithms allow either to join a fixed pattern or to track amoving target.Finally, Section 7 presents simulation results obtained on oursimulator, concerning a rather complicated scenario of mission.
Publish Year: 2013
Published in: Aerospace - IEEE
Number of Pages: 13
موضوع: مهندسی هوافضا
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: The role of the atmosphere in the provision of ecosystem services
Authors: Ellen J. Cooter, Anne Rea, Randy Bruins, Donna Schwede, Robin Dennis
Abstract: Solving the environmental problems that we are facing today requires holistic approaches to analysis and decision making that include social and economic aspects. The concept of ecosystem services, defined as the benefits people obtain from ecosystems, is one potential tool to perform such assessments. The objective of this paper is to demonstrate the need for an integrated approach that explicitly includes the contribution of atmospheric processes and functions to the quantification of air–ecosystem services. First, final and intermediate air–ecosystem services are defined. Next, an ecological production function for clean and clear air is described, and its numerical counterpart (the Community Multiscale Air Quality model) is introduced. An illustrative numerical example is developed that simulates potential changes in air–ecosystem services associated with the conversion of evergreen forest land in Mississippi, Alabama and Georgia to commercial crop land. This one-atmosphere approach captures a broad range of service increases and decreases. Results for the forest to cropland conversion scenario suggest that although such change could lead to increased biomass (food) production services, there could also be coincident, seasonally variable decreases in clean and clear air–ecosystem services (i.e., increased levels of ozone and particulate matter) associated with increased fertilizer application. Metrics that support the quantification of these regional air–ecosystem changes require regional ecosystem production functions that fully integrate biotic as well as abiotic components of terrestrial ecosystems, and do so on finer temporal scales than are used for the assessment of most ecosystem services.
Publish Year: 2013
Published in: Science of The Total Environment - Science Direct
Number of Pages: 12
موضوع: حفاظت از محیط زیست
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Construction of fuzzy ontologies from fuzzy XML models
Authors: Fu Zhang, Z.M. Ma, Li Yan
Abstract: The success and proliferation of the Semantic Web depends heavily on construction of Web ontologies. However, classical ontology construction approaches are not sufficient for handling imprecise and uncertain information that is commonly found in many application domains. Therefore, great efforts on construction of fuzzy ontologies have been made in recent years. In particular, XML is imposing itself as a standard for representing and exchanging information on the Web, topics related to the modeling of fuzzy data have become very interesting in the XML data context. Therefore, constructing fuzzy ontologies from fuzzy XML data resources may make the existing fuzzy XML data upgrade to Semantic Web contents, and the constructed fuzzy ontologies may be useful for improving some fuzzy XML applications.This paper proposes a formal approach and an automated tool for constructing fuzzy ontologies from fuzzy XML data resources. Firstly, we propose a formal definition of fuzzy XML models (including the document structure fuzzy DTDs and the document content fuzzy XML documents). On this basis, we propose a formal approach for constructing fuzzy ontologies from fuzzy XML models, i.e., transforming a fuzzy XML model (including fuzzy DTD and fuzzy XML document) into a fuzzy ontology. Also, we give the proof of correctness of the construction approach, and provide a detailed construction example. Furthermore, we implement a prototype tool called FXML2FOnto, which can automatically construct fuzzy ontologies from fuzzy XML models. Finally, in order to show that the constructed fuzzy ontologies may be useful for improving some fuzzy XML applications, we focus on investigating how to reason on fuzzy XML models (e.g., conformance, inclusion, and equivalence) based on the constructed fuzzy ontologies, and it turns out that the reasoning tasks of fuzzy XML models can be checked by means of the reasoning mechanism of fuzzy ontologies.
Publish Year: 2013
Published in: Knowledge-Based Systems - Science Direct
Number of Pages: 20
موضوع: XML ، فازی
ایران سای – مرجع مقالات علمی فنی مهندسی
حامی دانش بومی ایرانیان
