Definition, realization and evaluation of a software reference architecture for use in space applications

Metric-based Evaluation of Implemented Software Architectures

The polar-orbiting environmental satellite ENVISAT (ENVISAT = ENVIronmental SATellite), which has been launched in the night of February 28 to March 1, 2002 in Kourou (French Guayana) on board of an Ariane 5, carries ten instruments on board. These instruments observe land surfaces, oceans, polar ice caps and the atmosphere, in order to examine anthropogene environmental influences on the earth system. EN-VISAT is the largest satellite, developed by ESA (European Space Agency) up to now. Three of these ten instruments are remote sensing instruments for atmospheric chemistry: MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) and GOMOS (Global Ozone Monitoring by Occultation of Stars), which use different measurement techniques and geometry and which provide information about the content of different atmospheric trace gases. The subject of this thesis is the validation of these ENVISAT data by groundbased FTIR measurements (FTIR = Fourier Transform Infra Red). The Institute for Meteorology and Climate Research (IMK) operates two groundbased Fourier spectrometers in international cooperation with the Institutet for Rymdfysik (IRF) in Sweden and the University of Nagoya (Japan) in Kiruna (north Sweden) since 1996 and together with the Instituto Nacional de Meteorologia, (INM) in Izana (Tenerife Island) since 1999. From these measurements profiles and column amounts of O 3 , HCl, HF, HNO 3 , ClONO 2 , N 2 O, CH 4 , NO 2 , CO, NO and ClO are derived. Both stations in Kiruna and Izana are part of the NDSC (Network for the Detection of Stratospheric Change). As part of this network continuous ground-based measurements are performed, and are not limited by campaigns, as for example by balloonborne or airborne measurements. Therefore the ground-based measurements are particularly suitable for the long-term validation of satellite data. With the MIPAS-ESA measurements the vertical profiles and column amounts of O 3 , HNO 3 , CH 4 and N 2 O were compared, with the SCIAMACHY measurements the column amounts of O 3 and NO 2 . The results indicate that both the O 3 - and the HNO 3 -measurements of MIPAS-ESA are within the expectations. Thus the middle deviations of the column amounts are around ′5 %, those of the vertical profiles around ′10 %. The differences for the tropospheric gases CH 4 and N 2 O are as expected very large. For SCIAMACHY the middle deviations of 03 are around ′20 %, for NO 2 from +20 % to -40 %. The variability of the total column amounts are unrealistically large in comparison to atmospheric variability. In addition to the products, which were generated by the ESA processor, there are scientific evaluations for MIPAS and SCIAMACHY. These are included into this work. The results of MIPAS from a processor, which was developed at the IMK and is operated there, shows that the concistence of these data with the ground-based measurements is still better than from the ESA processor. Particularly in heights up to about 25 km the differences for the ground-based measurements are within the 1σ-noise-error. But also above these 25 km the deviations are smaller than those of the ESA processor.

In 1998, Ian Foster and Carl Kesselman, together with thirty distinguished experts in high-performance computing and networking, laid the foundations of a new computing model called GRID. Their vision was introduced in the book, The GRID: Blueprint for a New Computing Infrastructure (see review, SCPE Vol. 3, No. 3 ). The editors wrote: … A computational grid is a hardware and software infrastructure that provides dependable, consistent, pervasive, and inexpensive access to high-end computational capabilities… allowing new classes of applications to emerge… as yet, we have only a preliminary understanding of what these new applications will look like. Over the next five years, Grid computing became the hottest R&D field. Academia and national labs built experimental infrastructures, new startups were established to develop Grid technologies, and the HPC giant vendors joined the party. Each one pushed in a different direction based on what and how he believed Grid computing should look. It was only a matter of time until people started to ask what the Grid is all about. A survey of ten Grid experts produced ten different answers. The question remains without a clear answer, leaving many people confused. Ian Foster picked up the gloves. In his article, What is the GRID? A three point checklist (GRIDtoday, July 22, 2002: Vol. 1, No. 6), he redefines the Grid model to reflect the trades and changes in the field during the past five years. According to Foster, a Grid is a system that: Coordinates resources that are not subject to centralized control. Uses standard, open, general-purpose protocols and interfaces. Delivers a nontrivial quality of service. But Foster's new definition could not encompass all of the Grid's approaches. Moreover, Foster explained by example what the Grid is not: A cluster management system such as Sun's Sun Grid Engine, Platform's Load Sharing Facility, or Viridian's Portable Batch System can, when installed on a parallel computer or local area network, deliver quality of service guarantees and thus constitutes a powerful Grid resource. However, such a system is not a Grid itself, due to its centralized control of the hosts that it manages Within a week the responses started to come in. The first one was from Wolfgang Gentzsch, Director of Grid computing at Sun Microsystems (GRIDtoday, August 5, 2002: Vol. 1, No. 8). Gentzsch wrote: I very much like Ian's two earlier definitions. Combined, they may provide a very generic Grid definition. The new checklist, however, reduces the potential of a wide and rich variety of Grids, with different architectures, operational models, and applications, and may miss the chance to becoming widely accepted as a standard definition of the Grid. Why do we need a definition for the Grid? Can the Grid be defined? Is a definition is necessary to the Grid's development? The Grid is an open vision and thus cannot be defined. An attempt to define the Grid can only reach the foreseen technology horizon, and this horizon is only one to two years ahead. Grid computing is a paradigm in shift. New architectures and standards are changing the shape and direction of the Grid's development. In the past year one such prominent architecture was Open Grid Services Architecture (OGSA). The OGSA is the first attempt to bridge the gap between two cyberspace worlds: the Internet and the Grid. The Internet and the Grid are two different computing models. There are people who believe that the Grid is the next generation of the Internet and the World Wide Web, saying that the Great Global Grid is still many years away. Others state that the Grid will complement, not replace, the Internet as we know it. In 1998, when the Grid blueprint was published, a new Internet language appeared called eXtensible Markup Language (XML). XML is a development tool for a new Internet computing model known as Web Services. At that time, nobody understood that there is a relationship between Web Services and the Grid. Three years past before Steve Tuecke from Argonne National Laboratory started to write a spec for Grid Services. Later, people from IBM joined the mission and together they created OGSA. The OGSA specification outlines interfaces to grid computing software that comply with Web Services standards. If adopted, Grid services such as job scheduling, authentication, failure-detection, staging of applications and data, and migration of applications and data, will all be accessed through standard Web Services architecture. OGSA is basically where Grid meets Web Services and maybe the first step towards full integration of the Internet and the Grid. The Internet appeared a decade ago. In the beginning, the Net offered primitive applications: a mailing system, ftp services, and a web of home pages. Nobody asked, What is the Internet? The years passed and new emerging Internet technologies were developed. Today we can talk on the phone over the Net, chat with friends, and video conference with colleagues on the other side of the world. New computing and business models were developed: e-commerce, e-learning, e-science, and e-you-name-it. And nobody asks what the Internet is. The Grid is a super-model, a bag of networking models associated with many types of architectures, software packages, applications, and standards. Today, when people talk about the Grid they mention Data Grids, Science Grids, and Campus Grids. And at the same time they mention Farm computing, Peer-to-peer computing, and Utility computing, among others. Ten years from now many of today's technologies will disappear and new ones will be developed. I don't know how Grid computing will look a decade from now, but I know that we will have g-commerce, g-learning, g-science, and g-chat. Nobody will ask what the Grid is. It will be obvious, just as the Internet is today. Ami Marowka The Computer Aided Design Laboratory School of Engineering and Computer Science Hebrew University of Jerusalem

A major cause of many complications in the field of software architectures is the lack of appropriate abstractions for separating, combining and encapsulating concerns of various kinds in architectural descriptions. Architectures of most complex software-intensive systems involve concerns that inherently crosscut the natural boundaries of the elements composing the architecture descriptions. Crosscutting concerns intersect the common modularity of systems as prescribed by their architecture descriptions, by traversing both the components and connectors, i.e., the relationships among the components. Crosscutting concerns are critical aspects of many architectural problems. However, architectural descriptions written in special-purpose languages (ADLs) like Wright, Darwin, Rapide and Acme should support descriptions of multiple structures, which include diagrams, models and views, that intentionally address different kinds of concerns. ADLs should show how various concerns affect each other in architectural designs; they should also allow one to identify, analyze and elaborate architectural concerns that cut across several software components, such as transactions, security, load balancing, synchronization, reuse, customization, scalability, etc.; they should, but they do not. This dissertation presents a new approach to software architecture that is suitable for supporting concern-oriented development and documentation of architectures for software-intensive systems. This approach allows for creating and documenting a multidimensional software structure that is referred to as concern-oriented software architecture; it provides new mechanisms for encapsulating individual concerns into independent architectural constructs. The ultimate goal of this new approach is to provide support for achieving design by concerns all through the development and description of software architectures. Moving towards this goal, we present a particular concern-oriented architectural framework called Perspectival Concern-Spaces (PCS). The PCS Framework offers a flexible and extensible means a) for supporting advanced separation of concerns in architectural design, and in the construction and evolution of software-intensive systems; and b) for filling the gap between architectural descriptions and modern software development artifacts. To show the feasibility of the proposed approach, we provide new modeling techniques that are used to describe and apply an aspect-oriented architectural pattern, called the On-demand Remodularization pattern. We give several examples of how the PCS Framework can be used to integrate concern-oriented architectural documentations with mainstream software development artifacts.

European Cooperation for Space Standardization (ECSS) is an initiative established to develop a coherent, single set of user-friendly standards for use in all European space activities. In the autumn of 1993, several national space agencies in Europe, ESA and the European space industry joined forces to start developing space standards. ECSS standards must improve industrial efficiency and competitiveness, and satisfy European and international clients. The standards will apply as needed to any party participating in the definition, development, manufacturing, verification or operation of any assembly, equipment, subsystem or service used for any space mission. 1. INTRODUCTION ECSS, which stands for European Cooperation for Space Standardization, is an initiative designed to develop a coherent single set of user-friendly standards for the European space community which in this case means ESA and its member states, including their space industries. The European space business suffers from the multiplicity of standards and requirements used by the different space agencies in Europe. Although these requirements are essentially similar, the impact of the differences is nonetheless serious, leading in particular to high costs, lower effectiveness, a less compelitive industry and possible errors. This situation is expected to last until ECSS produces its standards, which will in turn help to solve the aforementioned problems. Back in 1988, in an attempt to improve the situation, Eurospace asked the director-generals of both ESA and CNES to make their organizations' product assurance requirements consistent. Efforts were pursued from 1991 to 1993 to meet this objective. By the end of that period, the European space community was in a position to meet this challenge. Based on a commercially oriented strategy, forces were joined to build a more comprehensive, coherent system to encompass space business activities as a whole rather than dealing only with product assurance aspects. The European space industry was therefore fully associated with ECSS from the outset. ECSS was actually born in the autumn of 1993, when the partners signed the ECSS terms of reference (TOR), which define the basic rules of the system. At this point, the partners jointly undertook the development of the system, designed to meet the main objective of providing a single coherent set of standards for use in all European space activities and particularly projects. 2. IMPORTANCE OF STANDARDS Today, standards are no longer considered as just impressive stacks of dusty papers containing unjustified requirements or constraints. Standardization is generally viewed as a process driving commercial viability and success. Successful companies recognise that developing and using standards is the path to remaining competitive and producing quality products In the first ECSS-industry meeting in October 1993, the ESA Director General stated that the time had come to harmonise existing space standards and to implement a system of common standards to enable the European space industry to become more efficient, more capable and more competitive in general. He stressed several points: • These standards must satisfy all European and international clients; Copyright © 1996 by CNES. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission 1 El Gammal • Existing standards which satisfy the require-ment should be retained, and new ones should be developed on the basis of solid reasoning and experience; • The European space industry must be a full partner in the preparation, writing and validation of these standards. Globally accepted European and international standards can promote the development, manufacture and sale of high-quality space products, which are not only demanded by the domestic clients, but also meet the needs of international customers. By abolishing the multiplicity of project requirements of the various partners in ECSS, and concentrating on a single set of standards from which all generic requirements of future space projects would be derived this initiative should drive an increase in industrial efficiency. This policy will generate more recurring products or services at reduced cost with consistently high quality. Standardization is an important tool during all programme phases to both reduce costs and enhance quality and communications. The goal of the ECSS standardization initiative system is to minimise life-cycle costs, while continually improving the quality, functional integrity and compatibility of all elements of a project. This will be achieved by applying common standards to hardware, software, information and all activities within a given project, and between different projects. 3. SCOPE OF ECSS STANDARDS ECSS standards are being drawn up for space projects and applications within the following categories: • project management requirements; • requirements for design, development, manufacturing, and verification of space systems and their constituent parts; • technical requirements for assemblies, equipment, subsystems and systems used for space missions. The ECSS standards will apply as needed to any party participating in the definition, development, manufacturing, verification or operation of any assembly, equipment, subsystems, system or service used for a European element of any space mission.

This paper deals with the development and the applications of a computational transient model of the VINCI cryogenic expander cycle upper stage rocket engine, tested in the frame of the FLPP Expander Demonstration Program managed by the European Space Agency (ESA). Snecma has been developing a transient system model of the VINCI engine since the beginning of the engine development, and the constant use of transient simulation was one of the major factors contributing to the success of the first two VINCI engines test campaigns. Simulation results have been found to be in good agreement with the measurements from the very first tests. The model accurately predicts the engine global behavior during start-up and shutdown, as well as the engine steady-state performance, and it also describes correctly the transient behavior of complex subsystems such as the combustion chamber or the turbopumps. This paper provides an overview of the physical content of the VINCI engine transient model. Simulation results from the model are compared with engine test data, and the model representativeness is discussed in detail. A focus is made on highly unsteady phenomena, such as valve maneuverings, and their effects on the whole engine behavior. I. Introduction HIS paper deals with the development and the applications of a computational transient model of the VINCI rocket engine. The VINCI is a cryogenic expander cycle engine, basis of a demonstration program preparing an application on the European launchers, in the frame of the European Space Agency (ESA) Future Launcher Preparatory Program (FLPP). The VINCI development in 200 5 and 2006 was conducted in the frame of the predevelopment of a cryogenic upper stage, under contract from the Centre National d’Etudes Spatiales (CNES), the French Space Agency, on behalf of ESA. The Space Engines Division of Snec ma in Vernon, France, acting as a prime contractor, is in charge in particular of the engine overall system design and integration. Snecma has been developing a transient system model of the VINCI engine since the beginning of the engine development, in order to predict its behavior during start-up and shutdown transients, as well as during potential failure scenarios. This model can also be used to identify possible undesirable unsteady effects that may occur during the engine transient operation phases, and to assess the consequences of any design changes. The constant use of tran sient system simulation has been one of the major success factors of the first two VINCI engines test campaigns that took place from May to July 2005 (M1 engine) and from November 2005 to February 2006 (M2 engine). During a test campaign, the model was used on a systematic basis in order to perform risk analysis for the subsequent tests, and to gain a physical knowledge of the engine behavior complementary to the one coming from raw measurements. Thanks to the intensive modeling work done at Snec ma, and to the experience gained from subsystem and component tests, simulation results were found to be in good agreement with measurements. A fairly good agreement was obtained from the very first tests, despite the fact that the VINCI engine is the first cryogenic expander cycle engine ever built and tested in Western Europe. The model accurately predicts the engine global behavior during start-up and shutdown, as well as the engine steady-state performance, and it also describes correctly the transient behavior of complex subsystems such as the combustion chamber or the turbopumps. This publication provides an overview of the physical content of the VINCI engine transient model, including the modeling process of the different subsystems. Simulation results from the model are compared with engine test data, and the model representativeness is discussed in detail. A focus is made on highly unsteady phenomena, such as valve maneuverings, and their effects on the whole engine behavior.

This thesis describes a number of instrumentation and mission design developments performed to prepare the European Space Agency’s (ESA’s) Euclid Mission. This space-based mission will enable unprecedented experimental probes of the nature of dark energy. As the Near-Infrared Photometry Scientist – one of three Instrument Scientists within the Euclid Consortium – my work focused on the mission’s near-infrared photometric channel, which is required for the photometric redshift measurements of the ~1.5 billion galaxies within the large Euclid imaging survey. This thesis addresses and solves a range of specific problems relating to implementation of this channel, with the ultimate goal of proving mission feasibility during the selection process of ESA’s Cosmic Vision Program. To that end, this thesis details requirement breakdowns and error budgets used to translate scientific requirements into lower level instrument requirements. The performance validation of the baseline implementation of the mission against high level requirements has formed an important part of the mission verification process; those applicable to the photometric channel are presented in this thesis. I have also developed a calibration strategy to meet the channel’s stringent high level calibration requirement. This includes specific work on optimizing the survey strategy for the retrospective calibration of the survey-wide dataset and also hardware development relating to a potential implementation of an internal flat-field calibration source. An assessment of the channel’s critical, single-point-failure filter wheel mechanism – which is needed to allow multi-band near-infrared photometry – is also detailed. Much of this effort has been incorporated into official Euclid documentation that has formed the basis of the Euclid Consortium’s response to the Cosmic Vision Program selection process. The baseline implementation of the near-infrared photometric channel, the performance of which was under my stewardship, meets all the high level science requirements.

This chapter describes the establishment process, purpose of establishment, mission, exploration plan, activities of the European Space Agency (ESA) and International Space Station (ISS), and an explanation of the contents of the treaty that is legal basis for its establishment. The European Space Agency (ESA) is an intergovernmental organization of 22 member states dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA has a worldwide staff of about 2,200 in 2018 and an annual budget of about € 6.68 billion (US $ 7.43 billion) in 2020. ESA also works closely with space organizations outside Europe. ESA has missions planned for Jupiter (JUICE, 2022) and others that will seek dark matter (Euclid, 2020) and observe the energetic universe (Athena, 2028). The International Space Station (ISS) is a space station (habitable artificial satellite) in low Earth orbit. The ISS programme is a joint project between five participating space agencies: NASA (United States), Roscomos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada).

Data acquired by spaceborne spectrometers operating in the visual (VIS) and near-infrared (NIR) spectral ranges, are commonly exploited to derive the microphysical properties of planetary atmospheric aerosols (e.g. Adriani et al., 2015; Sindoni et al., 2017; Fedorova et al., 2024; Oliva et al., 2016; Oliva et al., 2018; D’Aversa et al., 2022). The precision with which these properties can be constrained, depends on several parameters (e.g. optical constants, surface albedo spectrum, particles’ shape and size distribution, ecc.) and on the spectral information content in the data. VIS wavelengths alone (~ 0,4 – 0,7 μm) provide information on aerosols’ composition, particles’ density and sizes, allowing the estimation of the optical depth integrated along the line of sight (Oliva et al., 2016). However, in order to constrain these parameters with enhanced precision, the NIR range (~ 0,7 – 3,0 μm) is also required, since it allows to assess how the spectral shape bends towards longer wavelengths (Oliva et al., 2018).Our goal is to exploit the combined nadir datasets of the UVIS (0.2 – 0.65 µm) and LNO (2.2 – 3.8 µm) channels of the NOMAD spectrometer (Neefs et al., 2015) to contrain the microphysical properties of Martian dust (Oliva et al., 2025). The two spectral ranges present a large gap among each other, and this introduces biases in the retrieved parameters due to the unconstrained spectral information in the missing wavelengths. In order to benchmark these biases, we exploit MEx/OMEGA (Bibring et al., 2004) VNIR (0,35 – 1,05 µm) and SWIR-C (0.93 - 2.73 µm) channels’ data. Such an extended interval allows the retrieval of Martian dust clouds’ height and microphysical properties (e.g. Oliva et al., 2018; D’Aversa et al., 2022), that can be used as a proxy for the NOMAD retrievals. By studying dust’s densities and sizes 1) from the full OMEGA spectrum and 2) from the spectrum only covering UVIS and LNO wavelengths, we can derive the bias in the retrieved parameters. Moreover, this analysis allows to calibrate how many UVIS and LNO spectral points need to be considered in the retrieval, in order to balance the information content of the two channels.Preliminary results suggest that dust densities are systematically overestimated (as well as grains’ sizes to a lesser degree) if NIR wavelengths are completely neglected, while such a bias is reduced if LNO range is taken into account.ReferencesAdriani et al., 2015. Faint luminescent Ring over Saturn’s polar hexagon. Astrophys. J. Lett. 808 (1), 5. L16.Bibring et al., 2004. Omega: Observatoire pour La minéralogie, l’eau, Les Glaces Et l’activité. ESA SP-1240: Mars Express: The Scientific Payload. ESA Publications Division, Estec, Noordwijk, The Netherlands, pp. 37–49.D’Aversa et al., 2022. Vertical distribution of dust in the Martian atmosphere: OMEGA/Mex limb observations. Icarus 371, 114702.Fedorova et al., 2024. Distribution of atmospheric aerosols during the 2007 Mars dust storm (MY 28): Solar infrared occultation observations by SPICAM. Icarus 415, 116030Oliva et al., 2016. Clouds and hazes vertical structure of a Saturn’s giant vortex from Cassini/VIMS-V data analysis. Icarus 278, 215–237.Oliva et al., 2018. Properties of a Martian local dust storm in Atlantis Chaos from OMEGA/MEX data. Icarus.Oliva et al., 2025. Martian dust characterization: reanalysis of TGO/NOMAD UVIS and LNO channels’ nadir data. XX Congresso Nazionale di Scienze Planetarie, Pescara, 3-7 Febbraio 2025.Neefs et al, 2015. NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 1—design, manufacturing and testing of the infrared channelsApplied Optics 54, 28, 8494-8520.Sindoni et al., 2017. Characterization of the white ovals on Jupiter’s southern hemisphere using the first data by the Juno/JIRAM instrument. Geophys. Res. Lett. https://doi.org/10.1002/2017gl072940.AcknowledgementsExoMars is a space mission of the European Space Agency (ESA) and Roscosmos. The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (IASB- BIRA), assisted by Co-PI teams from Spain (IAA-CSIC), Italy (INAF-IAPS), and the United Kingdom (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with the financial and contractual coordination by the ESA Prodex Office (PEA 4000103401, 4000121493), by the Spanish MICINN through its Plan Nacional and by European funds under grants PGC2018-101836-B-I00 and ESP2017-87143-R (MINECO/FEDER), as well as by UK Space Agency through grants ST/V002295/1, ST/V005332/1, ST/Y000234/1 and ST/X006549/1 and Italian Space Agency through grant 2018-2-HH.0. The IAA/CSIC team acknowledges financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work was supported by the Belgian Fonds de la Recherche Scientifique – FNRS under grant numbers 30442502 (ET_HOME) and T.0171.16 (CRAMIC) and BELSPO BrainBe SCOOP Project. US investigators were supported by the National Aeronautics and Space Administration. Canadian investigators were supported by the Canada Space Agency.

Large and complex software systems cannot be created in one piece. They need to be separated into manageable units, i.e., modules, which can be developed independently from each other. Precise definition and documentation of the modules and other software artifacts is essential for a successful software project. The module documentation is part of the overall software architecture documentation. However, nowadays most of the utilized tools for documenting software architectures (e.g., word processors) are not fully sufficient for this task. This thesis provides a concept for an extensible tool, which is specialized for documenting software architectures and modules. The concept supports management and visualization of explicitly definable relations, e.g., dependencies among modules or references to external implementation artifacts. Moreover, this thesis suggests a template for module documentation based on its concept. Finally, a proof of concept prototype is implemented and evaluated with promising results.

Software architecture is an important key that guarantees services and an effective analysis tool that ensures efficient verification properties of software systems. This is confirmed by using architecture description languages (ADL). The precise semantics of B method and its powerful data abstraction allow software architects to specify architectural elements behavior explicitly, to verify their semantics using powerful tools that are designed for the B method. In this paper, we define the behavioral aspects of software architecture using the B method. We use this formal method to define the behavioral aspects of COSA, which is a metamodel for software architecture. We also provide a B formal specification of the proposed aspects.

The integration of independently-developed applications into an efficient system, particularly in a distributed setting, is the core issue addressed in this work. Cooperation between researchers across various field boundaries in order to solve complex problems has become commonplace. Due to the multidisciplinary nature of such efforts, individual applications are developed independent of the integration process. The integration of individual applications into a fully-functioning architecture is a complex and multifaceted task. This thesis extends a component-based architecture, previously developed by the authors, to allow the integration of various software applications which are deployed in a distributed setting. The test bed for the framework is the EU project XPERO, the goal of which is robot learning by experimentation. The task at hand is the integration of the required applications, such as planning of experiments, perception of parametrized features, robot motion control and knowledge-based learning, into a coherent cognitive architecture. This allows a mobile robot to use the methods involved in experimentation in order to learn about its environment. To meet the challenge of developing this architecture within a distributed, heterogeneous environment, the authors specified, defined, developed, implemented and tested a component-based architecture called XPERSIF. The architecture comprises loosely-coupled, autonomous components that offer services through their well-defined interfaces and form a service-oriented architecture. The Ice middleware is used in the communication layer. Its deployment facilitates the necessary refactoring of concepts. One fully specified and detailed use case is the successful integration of the XPERSim simulator which constitutes one of the kernel components of XPERO.The results of this work demonstrate that the proposed architecture is robust and flexible, and can be successfully scaled to allow the complete integration of the necessary applications, thus enabling robot learning by experimentation. The design supports composability, thus allowing components to be grouped together in order to provide an aggregate service. Distributed simulation enabled real time tele-observation of the simulated experiment. Results show that incorporating the XPERSim simulator has substantially enhanced the speed of research and the information flow within the cognitive learning loop.

Speleology as an analogue to space exploration: The ESA CAVES training programme

It is an undeniable fact that software plays an important role in our lives. We use the software to play our music, to check our e-mail, or even to help us drive our car. Thus, the quality of software directly influences the quality of our lives. However, the traditional Software Engineering paradigm is not able to cope with the increasing demands in quantity and quality of produced software. Thus, a new paradigm of Model Driven Software Engineering (MDSE) is quickly gaining ground. MDSE promises to solve some of the problems of traditional Software Engineering (SE) by raising the level of abstraction. Thus, MDSE proposes the use of models and model transformations, instead of textual program files used in traditional SE, as means of producing software. The models are usually graph-based, and are built by using graphical notations – i.e. the models are represented diagrammatically. The advantages of using graphical models over text files are numerous, for example it is usually easier to deduce the relations between different model elements in their diagrammatic form, thus reducing the possibility of defects during the production of the software. Furthermore, formal model transformations can be used to produce different kinds of artifacts from models in all stages of software production. For example, artifacts that can be used as input for model checkers or simulation tools can be produced. This enables the checking or simulation of software products in the early phases of development, which further reduces the probability of defects in the final software product. However, methods and techniques to support MDSE are still not mature enough. In particular methods and techniques for model configuration management (MCM) are still in development, and no generic MCM system exists. In this thesis, I describe my research which was focused on developing methods and techniques to support generic model configuration management. In particular, during my research, I focused on developing methods and techniques for supporting model evolution and model co-evolution. Described methods and techniques are generic and are suitable for a state-based approach to model configuration management. In order to support the model evolution, I developed methods for the representation, calculation, and visualization of state-based model differences. Unlike in previously published research, where these three aspects of model differences are dealt with in separation, in my research all these three aspects are integrated. Thus, the result of model differences calculation algorithm is in the format which is described by my research on model differences representation. The same representation format of model differences is used as a basis of my approach to differences visualization. It is important to notice that the developed representation format for model differences is metamodel independent, and thus is generic, i.e., it can be used to represent differences between all graph-based models. Model co-evolution is a term that describes the problem of adapting models when their metamodels evolve. My solution to this problem has three steps. In the first step a special metamodel MMfMM is introduced. Unlike in traditional approaches, where metamodels are represented as instances of a metametamodel, in my approach the metamodels are represented by models which are instances of an MMfMM. In the second step, since metamodels are represented by models, previously defined methods and techniques for model evolution are reused to represent and calculate the metamodel differences. In the final step I define an algorithm that uses the calculated metamodel differences to adapt models conforming to the evolved metamodel. In order to validate my approaches to model evolution and model co-evolution, I have developed a tool for comparing models and visualizing resulting differences, and a tool for model co-evolution. Moreover, I have developed a method to compare tools for model comparison, and using this method I have conducted a series of experiments in which I compared the tool I developed to an industrial tool called EMFCompare. The results of these experiments are also presented in the thesis. Furthermore, in order to validate my tool and approach to model co-evolution, I have also specified and conducted several experiments. The results of these experiments are also presented in the thesis.

This thesis work presents the implementation and validation of image processing problems in hardware to estimate the performance and precision gain. It compares the implementation for the addressed problem on a Field Programmable Gate Array (FPGA) with a software implementation for a General Purpose Processor (GPP) architecture. For both solutions the implementation costs for their development is an important aspect in the validation. The analysis of the flexibility and extendability that can be achieved by a modular implementation for the FPGA design was another major aspect. This work is based upon approaches from previous work, which included the detection of Binary Large OBjects (BLOBs) in static images and continuous video streams [13, 15]. One addressed problem of this work is the tracking of the detected BLOBs in continuous image material. This has been implemented for the FPGA platform and the GPP architecture. Both approaches have been compared with respect to performance and precision. This research project is motivated by the MI6 project of the Computer Vision research group, which is located at the Bonn-Rhein-Sieg University of Applied Sciences. The intent of the MI6 project is the tracking of a user in an immersive environment. The proposed solution is to attach a light emitting device to the user for tracking the created light dots on the projection surface of the immersive environment. Having the center points of those light dots would allow the estimation of the user’s position and orientation. One major issue that makes Computer Vision problems computationally expensive is the high amount of data that has to be processed in real-time. Therefore, one major target for the implementation was to get a processing speed of more than 30 frames per second. This would allow the system to realize feedback to the user in a response time which is faster than the human visual perception. One problem that comes with the idea of using a light emitting device to represent the user, is the precision error. Dependent on the resolution of the tracked projection surface of the immersive environment, a pixel might have a size in cm2. Having a precision error of only a few pixels, might lead to an offset in the estimated user’s position of several cm. In this research work the development and validation of a detection and tracking system for BLOBs on a Cyclone II FPGA from Altera has been realized. The system supports different input devices for the image acquisition and can perform detection and tracking for five to eight BLOBs. A further extension of the design has been evaluated and is possible with some constraints. Additional modules for compressing the image data based on run-length encoding and sub-pixel precision for the computed BLOB center-points have been designed. For the comparison of the FPGA approach for BLOB tracking a similar implementation in software using a multi-threaded approach has been realized. The system can transmit the detection or tracking results on two available communication interfaces, USB and RS232. The analysis of the hardware solution showed a similar precision for the BLOB detection and tracking as the software approach. One problem is the strong increase of the allocated resources when extending the system to process more BLOBs. With one of the applied target platforms, the DE2-70 board from Altera, the BLOB detection could be extended to process up to thirty BLOBs. The implementation of the tracking approach in hardware required much more effort than the software solution. The design of high level problems in hardware for this case are more expensive than the software implementation. The search and match steps in the tracking approach could be realized more efficiently and reliably in software. The additional pre-processing modules for sub-pixel precision and run-length-encoding helped to increase the system’s performance and precision.