1,006 research outputs found

    Pristup specifikaciji i generisanju proizvodnih procesa zasnovan na inženjerstvu vođenom modelima

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    In this thesis, we present an approach to the production process specification and generation based on the model-driven paradigm, with the goal to increase the flexibility of factories and respond to the challenges that emerged in the era of Industry 4.0 more efficiently. To formally specify production processes and their variations in the Industry 4.0 environment, we created a novel domain-specific modeling language, whose models are machine-readable. The created language can be used to model production processes that can be independent of any production system, enabling process models to be used in different production systems, and process models used for the specific production system. To automatically transform production process models dependent on the specific production system into instructions that are to be executed by production system resources, we created an instruction generator. Also, we created generators for different manufacturing documentation, which automatically transform production process models into manufacturing documents of different types. The proposed approach, domain-specific modeling language, and software solution contribute to introducing factories into the digital transformation process. As factories must rapidly adapt to new products and their variations in the era of Industry 4.0, production must be dynamically led and instructions must be automatically sent to factory resources, depending on products that are to be created on the shop floor. The proposed approach contributes to the creation of such a dynamic environment in contemporary factories, as it allows to automatically generate instructions from process models and send them to resources for execution. Additionally, as there are numerous different products and their variations, keeping the required manufacturing documentation up to date becomes challenging, which can be done automatically by using the proposed approach and thus significantly lower process designers' time.У овој дисертацији представљен је приступ спецификацији и генерисању производних процеса заснован на инжењерству вођеном моделима, у циљу повећања флексибилности постројења у фабрикама и ефикаснијег разрешавања изазова који се појављују у ери Индустрије 4.0. За потребе формалне спецификације производних процеса и њихових варијација у амбијенту Индустрије 4.0, креиран је нови наменски језик, чије моделе рачунар може да обради на аутоматизован начин. Креирани језик има могућност моделовања производних процеса који могу бити независни од производних система и тиме употребљени у различитим постројењима или фабрикама, али и производних процеса који су специфични за одређени систем. Како би моделе производних процеса зависних од конкретног производног система било могуће на аутоматизован начин трансформисати у инструкције које ресурси производног система извршавају, креиран је генератор инструкција. Такође су креирани и генератори техничке документације, који на аутоматизован начин трансформишу моделе производних процеса у документе различитих типова. Употребом предложеног приступа, наменског језика и софтверског решења доприноси се увођењу фабрика у процес дигиталне трансформације. Како фабрике у ери Индустрије 4.0 морају брзо да се прилагоде новим производима и њиховим варијацијама, неопходно је динамички водити производњу и на аутоматизован начин слати инструкције ресурсима у фабрици, у зависности од производа који се креирају у конкретном постројењу. Тиме што је у предложеном приступу могуће из модела процеса аутоматизовано генерисати инструкције и послати их ресурсима, доприноси се креирању једног динамичког окружења у савременим фабрикама. Додатно, услед великог броја различитих производа и њихових варијација, постаје изазовно одржавати неопходну техничку документацију, што је у предложеном приступу могуће урадити на аутоматизован начин и тиме значајно уштедети време пројектаната процеса.U ovoj disertaciji predstavljen je pristup specifikaciji i generisanju proizvodnih procesa zasnovan na inženjerstvu vođenom modelima, u cilju povećanja fleksibilnosti postrojenja u fabrikama i efikasnijeg razrešavanja izazova koji se pojavljuju u eri Industrije 4.0. Za potrebe formalne specifikacije proizvodnih procesa i njihovih varijacija u ambijentu Industrije 4.0, kreiran je novi namenski jezik, čije modele računar može da obradi na automatizovan način. Kreirani jezik ima mogućnost modelovanja proizvodnih procesa koji mogu biti nezavisni od proizvodnih sistema i time upotrebljeni u različitim postrojenjima ili fabrikama, ali i proizvodnih procesa koji su specifični za određeni sistem. Kako bi modele proizvodnih procesa zavisnih od konkretnog proizvodnog sistema bilo moguće na automatizovan način transformisati u instrukcije koje resursi proizvodnog sistema izvršavaju, kreiran je generator instrukcija. Takođe su kreirani i generatori tehničke dokumentacije, koji na automatizovan način transformišu modele proizvodnih procesa u dokumente različitih tipova. Upotrebom predloženog pristupa, namenskog jezika i softverskog rešenja doprinosi se uvođenju fabrika u proces digitalne transformacije. Kako fabrike u eri Industrije 4.0 moraju brzo da se prilagode novim proizvodima i njihovim varijacijama, neophodno je dinamički voditi proizvodnju i na automatizovan način slati instrukcije resursima u fabrici, u zavisnosti od proizvoda koji se kreiraju u konkretnom postrojenju. Time što je u predloženom pristupu moguće iz modela procesa automatizovano generisati instrukcije i poslati ih resursima, doprinosi se kreiranju jednog dinamičkog okruženja u savremenim fabrikama. Dodatno, usled velikog broja različitih proizvoda i njihovih varijacija, postaje izazovno održavati neophodnu tehničku dokumentaciju, što je u predloženom pristupu moguće uraditi na automatizovan način i time značajno uštedeti vreme projektanata procesa

    Software Design Change Artifacts Generation through Software Architectural Change Detection and Categorisation

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    Software is solely designed, implemented, tested, and inspected by expert people, unlike other engineering projects where they are mostly implemented by workers (non-experts) after designing by engineers. Researchers and practitioners have linked software bugs, security holes, problematic integration of changes, complex-to-understand codebase, unwarranted mental pressure, and so on in software development and maintenance to inconsistent and complex design and a lack of ways to easily understand what is going on and what to plan in a software system. The unavailability of proper information and insights needed by the development teams to make good decisions makes these challenges worse. Therefore, software design documents and other insightful information extraction are essential to reduce the above mentioned anomalies. Moreover, architectural design artifacts extraction is required to create the developer’s profile to be available to the market for many crucial scenarios. To that end, architectural change detection, categorization, and change description generation are crucial because they are the primary artifacts to trace other software artifacts. However, it is not feasible for humans to analyze all the changes for a single release for detecting change and impact because it is time-consuming, laborious, costly, and inconsistent. In this thesis, we conduct six studies considering the mentioned challenges to automate the architectural change information extraction and document generation that could potentially assist the development and maintenance teams. In particular, (1) we detect architectural changes using lightweight techniques leveraging textual and codebase properties, (2) categorize them considering intelligent perspectives, and (3) generate design change documents by exploiting precise contexts of components’ relations and change purposes which were previously unexplored. Our experiment using 4000+ architectural change samples and 200+ design change documents suggests that our proposed approaches are promising in accuracy and scalability to deploy frequently. Our proposed change detection approach can detect up to 100% of the architectural change instances (and is very scalable). On the other hand, our proposed change classifier’s F1 score is 70%, which is promising given the challenges. Finally, our proposed system can produce descriptive design change artifacts with 75% significance. Since most of our studies are foundational, our approaches and prepared datasets can be used as baselines for advancing research in design change information extraction and documentation

    The Universal Safety Format in Action: Tool Integration and Practical Application

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    Designing software that meets the stringent requirements of functional safety standards imposes a significant development effort compared to conventional software. A key aspect is the integration of safety mechanisms into the functional design to ensure a safe state during operation even in the event of hardware errors. These safety mechanisms can be applied at different levels of abstraction during the development process and are usually implemented and integrated manually into the design. This does not only cause significant effort but does also reduce the overall maintainability of the software. To mitigate this, we present the Universal Safety Format (USF), which enables the generation of safety mechanisms based on the separation of concerns principle in a model-driven approach. Safety mechanisms are described as generic patterns using a transformation language independent from the functional design or any particular programming language. The USF was designed to be easily integrated into existing tools and workflows that can support different programming languages. Tools supporting the USF can utilize the patterns in a functional design to generate and integrate specific safety mechanisms for different languages using the transformation rules contained within the patterns. This enables not only the reuse of safety patterns in different designs, but also across different programming languages. The approach is demonstrated with an automotive use-case as well as different tools supporting the USF

    ENHANCING THE OPERATIONAL RESILIENCE OF CYBER- MANUFACTURING SYSTEMS (CMS) AGAINST CYBER-ATTACKS

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    Cyber-manufacturing systems (CMS) are interconnected production environments comprised of complex and networked cyber-physical systems (CPS) that can be instantiated across one or many locations. However, this vision of manufacturing environments ushers in the challenge of addressing new security threats to production systems that still contain traditional closed legacy elements. The widespread adoption of CMS has come with a dramatic increase in successful cyber-attacks. With a myriad of new targets and vulnerabilities, hackers have been able to cause significant economic losses by disrupting manufacturing operations, reducing outgoing product quality, and altering product designs. This research aims to contribute to the design of more resilient cyber-manufacturing systems. Traditional cybersecurity mechanisms focus on preventing the occurrence of cyber-attacks, improving the accuracy of detection, and increasing the speed of recovery. More often neglected is addressing how to respond to a successful attack during the time from the attack onset until the system recovery. We propose a novel approach that correlates the state of production and the timing of the attack to predict the effect on the manufacturing key performance indicators. Then a real-time decision strategy is deployed to select the appropriate response to maintain availability, utilization efficiency, and a quality ratio above degradation thresholds until recovery. Our goal is to demonstrate that the operational resilience of CMS can be enhanced such that the system will be able to withstand the advent of cyber-attacks while remaining operationally resilient. This research presents a novel framework to enhance the operational resilience of cyber-manufacturing systems against cyber-attacks. In contrast to other CPS where the general goal of operational resilience is to maintain a certain target level of availability, we propose a manufacturing-centric approach in which we utilize production key performance indicators as targets. This way we adopt a decision-making process for security in a way that is aligned with the operational strategy and bound to the socio-economic constraints inherent to manufacturing. Our proposed framework consists of four steps: 1) Identify: map CMS production goals, vulnerabilities, and resilience-enhancing mechanisms; 2) Establish: set targets of performance in production output, scrap rate, and downtime at different states; 3) Select: determine which mechanisms are needed and their triggering strategy, and 4) Deploy: integrate into the operation of the CMS the selected mechanisms, threat severity evaluation, and activation strategy. Lastly, we demonstrate via experimentation on a CMS testbed that this framework can effectively enhance the operational resilience of a CMS against a known cyber-attack

    Ad hoc HLA simulation model derived from a model-based traffic scenario

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    Modern highly automated and autonomous traffic systems and sub-systems require new approaches to test their functional safety in the context of validation and verification. One approach that has taken a leading role in current research is scenario-based testing. For various reasons, simulation is considered to be the most practicable solution for a wide range of test scenarios. However, this is where many existing simulation systems in research reach their limits. In order to be able to integrate the widest possible range of systems to be tested into the simulation, the use of co-simulation has proven to be particularly useful. In this work, the High-Level Architecture defined in the IEEE 1516-2010 standard is specifically addressed, and a concept is developed that establishes the foundation for the feasible use of scenario-based distributed co-simulation on its basis. The main challenge identified and addressed is the resolution of the double-sided dependency between scenario and simulation models. The solution was to fully automate the generation and instantiation of the simulation environment on the basis of a scenario instance. Finally, the developed concept was implemented as a prototype, and the resulting process for its use is presented here using an example scenario. Based on the experience gained during the creation of the concept and the prototype, the next steps for future work are outlined in conclusion

    A Graph Database Design for Multi-Domain Model Management

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    Provision and Collection of Safety Evidence: A Systematic Literature Review

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    Safety-Critical Systems (SCS) are becoming more and more present in modern societies’ daily lives, increasing people’s dependence on them. Current SCS are firmly based on computational technology; possible failures in the operation of these systems can lead to accidents and endanger human life, as well as damage the environment and property. SCS are present in many areas such as avionics, automotive systems, industrial plants (chemical, oil & gas, and nuclear), medical devices, railroad control, defense, and aerospace systems. Companies that develop SCS must present evidence of their safety to obtain certification and authorization. This paper presents a Systematic Literature Review (SLR) to investigate processes, tools, and techniques for collecting and managing safety evidence in SCS. The authors conducted this SLR according to the guidelines proposed by Kitchenham and Charters. The SLR comprises seven (7) research questions that investigate essential aspects of collecting and managing safety evidence. The primary studies analyzed in this SLR were selected based on a search string applied into four data sources: ACM, IEEE Xplore, SpringerLink, and ScienceDirect. Data extraction considered (fifty-one) 51 primary studies. The authors identified eleven (11) different approaches covering processes, tools, and techniques for collecting and managing safety evidence. Despite other SLR works conducted about safety evidence, none of them focused on the details related to safety evidence collection. We found that very few approaches focused specifically on the process of collecting safety evidence

    Review and proposition for model-based multivariable-multiobjective optimisation of extrusion-based bioprinting

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    Consequent to the development of bioprinting technologies for biomedical applications, especially in tissue engineering, a comprehensive review of extrusion-based bioprinting (EBB) has been written. The review was executed in a manner that laid a foundation for effective optimisation strategies to improve the print resolution or shape fidelity and cell viability of EBB through bioink. However, before achieving this aim the shearing characteristic of the bioink (i.e., shear-thinning or thickening) was described by the Ostwald-de Waele and Herschel-Bulkley models, among other reported models. The dependence of bioink shearing characteristics on temperature and time was also discussed. Emphasis on how these dependencies can be influenced by crosslinking of bioink molecules was further highlighted, which can be covalent (chemical-, photo-cross-linking, etc.) or noncovalent (physical cross-linking, host-guest inclusion, ionic interaction, etc.). Models from literature that can physically describe print resolution and cell viability in EBB were discussed and compared. Therefore, multivariable-multiobjective optimisation strategies were proposed with these models.Univerzita Tomáše Bati ve Zlíně, (CZ.02.2.69/0.0/0.0/19_073/0016941)Tomas Bata University, Zlin, Czech Republic [CZ.02.2.69/0.0/0.0/19_073/0016941

    Design of the Electronics Subsystem for a High-Resolution Electro-Optical Payload Using Systems Engineering Approach

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    Satellite imagers, in contrast to commercial imagers, demand exceptional performance and operate under harsh conditions. The camera is an essential part of an Earth Observation Electro Optical (EO) payload that is designed in response to needs such as military demands, changes in world politics, inception of new technologies, operational requirements and experiments. As one of the key subsystems, the Imager Electronics Subsystem of a high-resolution EO payload plays very important role in the accomplishment of mission objectives and payload goals. Hence, these Electronics Subsystems require a special design approach optimised for their needs and meticulous characterizations of high-resolution space applications. This dissertation puts forward the argument that the system being studied is a subsystem of a larger system and that systems engineering principles can be applied to the subsystem design process also. The aim of this dissertation is to design the Imager Electronics Subsystem of a high-resolution Electro Optical Payload using a systems engineering approach to represent a logical integration and test flow using the space industry guidelines. The Imager Electronics Subsystem consists of group of elements forming the functional chain from the Image Sensors on the Focal Plane down to electrical interface to the Data Handling Unit and power interface of the satellite. This subsystem is responsible for collecting light in different spectral bands, converting this light to data of different spectral bands from image sensors for high-resolution imaging, performing operations for aligning, tagging and multiplexing along with incorporating internal and external interfaces
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