P-SEMP: A platform for systems engineering modeling and planning

Systems engineering management and planning has long been a realm dominated by arcane standards, by the weight of years of practice, and by authority. However, with technological advances and the desire to solve socio-technical problems at the level of increasingly complex systems, authority alone is no longer sufficient for the justification of systems engineering practice. As new systems engineering methodologies are bought and sold in the transition towards model-based systems engineering, there is an imperative for the systems engineering practitioner to develop new techniques for estimating project performance before project completion. That is, whether debating appropriate corrective actions for a project at risk of going over budget or over schedule, or when planning a new systems engineering methodology, the systems engineer must forecast planned performance of systems engineering tasks. To this end, the International Council of Systems Engineers (INCOSE) and others have sought to bolster systems engineering measurement and the development of standardized leading indicators of systems engineering performance, which are thought to give insight into future performance in the course of program performance. Recent efforts have produced models of systems engineering performance; however, no model is yet sufficient for addressing which tasks in support of standardized processes should be planned in a systems engineering methodology. This document lays out how such a capability might be implemented by a platform for the numerical comparison of systems engineering methodologies. The idea of a platform for systems engineering modeling and planning is called P-SEMP. There are two threads in this document: a thesis and a methodology. First and foremost, the document is a thesis. The thesis, called at times the P-SEMP Thesis, is a formal argument as to how to address the problem of systems engineering task planning constructed on the basis of gaps, research questions, hypotheses, experiments, and their results. The P-SEMP Thesis aims to prove the best means for determining which systems engineering methodologies, and in particular which methods for a given systems engineering process, are better or worse. Enabling the argument of the P-SEMP Thesis is the P-SEMP Methodology, which is rooted in the fundamentals of modeling and simulation theory but made specific to the class of problems involved in systems engineering methodology comparison. The P-SEMP Methodology describes how to build a platform for P-SEMP and what a platform may entail, and the methodology is supported by a conceptual architecture description. The combined product of the P-SEMP Methodology and conceptual architecture description is a recipe: first, a recipe in terms of the proposed experiments, and then a recipe for the experimental results and conclusions of the P-SEMP Thesis and how its findings may be further applied. In order to render the P-SEMP Thesis manageable in scope, the focus will be placed on tasks surrounding the systems engineering process of validation. Validation, in different senses, can occur both early and late in the system life cycle. While validation is a controversial term, many authors agree that efforts around feasibility assessment, requirements quantification, and the early evaluation of system architectures and design against these requirements are crucial steps in early-phase validation to ensure that the system will meet stakeholder expectations before proceeding with the entirety of the system lifecycle. Concretely, as proposed sets of tasks, a portion of an Object-Oriented Systems Engineering Methodology-inspired process for Spacecraft Requirements Derivation is compared against the State Analysis Model Development method, and subsequently a third method is proposed as well regarding validation concepts. These methods for validation will be modeled and compared using the tooling developed in support of the argument for a platform for systems engineering modeling and planning, the P-SEMP Thesis, and be constructed according to the P-SEMP Methodology with results as shown in the conceptual architecture description for Platform 0.1 and Platform 1.0. The result of the experimental efforts culminates, in a concrete sense, with a domain-specific language for describing tasks in a manner suitable for simulation of the method models. However, leading indicator models are not forgotten; one in particular is replicated and added to a system modeling environment alongside the method models --- however, serious issues in parameterization are uncovered in these leading indicator models and they may not provide much insight towards task planning. Due to these issues and more, a hybrid model proved infeasible in the current situation, leading to the evolution from conceptual Platform 0.1 to the final Platform 1.0. Additionally, as the Spacecraft Requirements Derivation method is proposed specifically for a canonical system FireSat, specific modeling practice in SysML will be proposed to represent the third proposed SE methodology being compared, which requires representation of designs of experiments and probability distributions in the course of ensuring system feasibility. Another motivation for incorporating these expressions into a system model is to ensure the correctness of analytical models which underlay validation processes. This correctness is established by model verification and validation. As these analytical models represent the system from different perspectives, it is beneficial for them to be closely coupled to a unified system model depiction. However, a gap exists where while such capability is known for Multidisciplinary Design Optimization (MDO) and system models, it does not yet exist for Robust Design Simulation (RDS) or techniques for probabilistic or uncertain design processes in conjunction with a system model. Such a technology helps to support the activities above and improves confidence in the results of the early-phase system validation actions. In summation, according to the argument of the P-SEMP Thesis and the practice of the P-SEMP Methodology, a leading indicator model is replicated and found wanting. Systems engineering method model simulations are formulated, and a domain-specific language is created to capture them in the system model for exploration of task architecture. Finally, broader description of designs of experiments and probability are incorporated to improve analytical integration capabilities required for full validation activities in support of greater systems engineering methodology capability. Synthesizing the experimental results is the P-SEMP conceptual architecture Platform 1.0, which serves as a new baseline for systems engineering task planning and comparison, and which places the results into the greater context of how to build a platform and use the platform. Altogether, these pieces outline a platform for systems engineering modeling and planning on the basis of constructing a suitable platform through various models and exercising the resulting platform, thus improving systems engineering methodology analysis. Specifically, the thesis demonstrates how P-SEMP is the first known technique for SE methodology selection that supports 1) mathematical models of task performance, 2) analysis of SE methods as tasks in a concrete sense, 3) inclusion likewise of soft or subjective criteria, and 4) expandability to investigate new or different SE method proposals in a unified and effective manner.Ph.D

Automating System-Level Data-Interchange Software Through a System Interface Description Language

RÉSUMÉ Les plates-formes d'aujourd'hui, telles que les simulateurs de missions (FMS), présentent un niveau sans précédent d'intégration de systèmes matériels et logiciels. Dans ce contexte, les intégrateurs de systèmes sont confrontés à une hétérogénéité d'interfaces système qui doivent être alignées et reliées ensemble afin de fournir les capacités prévues d'une plate-forme. Le seul aspect des échanges de données système est problématique allant de données désalignées jusqu'à des environnements multi-architecturaux utilisant différents types de protocoles de communication. Les intégrateurs sont également confrontés à des défis similaires lors de l'interaction de multiples plates-formes ensemble à travers des environnements de simulation distribuée où chaque plate-forme peut être considérée comme un système avec sa propre interface distincte. D'autre part, permettre la réutilisation de système à travers diverses plates-formes en support aux gammes de produits est un défi pour les fournisseurs de systèmes, car ils doivent adapter leurs interfaces système à des plates-formes hétérogènes faisant donc face aux mêmes difficultés que les intégrateurs. En outre, l'introduction de modifications aux interfaces système afin de répondre aux besoins tardifs d'affaires, ou à des contraintes de performance imprévues, par exemple, est d'autant plus ardue que leurs impacts sont difficiles à prévoir et que leurs effets sont souvent décelés tard dans le processus d'intégration. En conséquence, cette thèse aborde la nécessité de simplifier l'intégration et l'interopérabilité système afin de réduire leurs coûts associés et d'accroître leur efficacité ainsi que leur efficience. Elle est destinée à apporter de nouvelles avancées dans les domaines de l'intégration système et de l'interopérabilité système. Notamment, en établissant une taxonomie commune, et en augmentant la compréhension des interfaces système, des divers aspects impactant les échanges de données système, des considérations des environnements multi-architecturaux, ainsi que des facteurs permettant la gouvernance d'interface ainsi que de la réutilisation système. À cette fin, deux objectifs de recherche ont été formulés. Le premier objectif vise à définir un langage utilisé pour décrire les interfaces système et les divers aspects entourant leurs échanges de données. Par conséquent, trois aspects principaux sont étudiés relatifs aux interfaces système: les éléments de langage pertinents utilisés pour les décrire, la modélisation des interfaces système avec ce langage, et la capture des considérations multi-architecturales. Le second objectif vise à définir une méthode pour automatiser le logiciel responsable des échanges de données système comme moyen pour simplifier les tâches impliquées dans l'intégration et l'interopérabilité système. Par conséquent, les compilateurs de modèles et les techniques de génération de code sont étudiés. La démonstration de ces objectifs apporte de nouvelles avancées dans l'état de l'art de l'intégration système et de l'interopérabilité système. Notamment, ceci culmine en un nouveau langage de description d'interface système, SIDL, utilisé pour capturer les interfaces système et les divers aspects entourant leurs échanges de données, ainsi qu'en une nouvelle méthode pour automatiser le logiciel d'échange de données au niveau système à partir des interfaces systèmes capturées dans ce langage. L'avènement de SIDL contribue également une nouvelle taxonomie fournissant une perspective complète sur l'interopérabilité système ainsi qu'en un langage commun qui peut être partagé entre les parties prenantes, tels que les intégrateurs, les fournisseurs et les experts système. Étant agnostique aux architectures, SIDL fournit un seul point de vue architectural supervisant toutes les interfaces système et capture les considérations multi-architecturales ce qui n'a jamais été réalisé avant ce travail. D'autant plus, un générateur de code SIDL est introduit présentant la nouveauté de générer le logiciel d'échange de données à partir d'un bassin plus riche d'information, notamment à partir des relations système de haut niveau allant jusqu'au bas niveau couvrant les détails protocolaires et d'encodage. En raison des considérations multi-architecturales qui sont capturées nativement dans SIDL, ceci permet au générateur de code d'être agnostique aux architectures le rendant réutilisable dans d'autres contextes. Cette thèse ouvre également la voie à de futures recherches bâtissant sur ses contributions. Elle propose même une vision pour le développement d'applications logicielles avec comme objectif final de repousser encore plus loin les limites de la simplification et de l'automatisation des tâches liées à l'intégration et à l'interopérabilité système.----------ABSTRACT Today’s platforms, such as full mission simulators (FMSs), exhibit an unprecedented level of hardware and software system integration. In this context, system integrators face heterogeneous system interfaces which need to be aligned and interconnected together in order to deliver a platform's intended capabilities. The sole aspect of the data systems exchange is problematic ranging from data misalignment up to multi-architecture environments over varying kinds of communication protocols. Similar challenges are also faced by integrators when interoperating multiple platforms together through distributed simulation environments where each platform can be seen as a system with its own distinct interface. On the other hand, enabling system reuse across multiple platforms for product line support is challenging for system suppliers, as they need to adapt system interfaces to heterogeneous platforms therefore facing similar challenges as integrators. Furthermore, the introduction of system interface changes in order to respond to late business needs, or unforeseen performance constraints for instance, is even more arduous as impacts are challenging to predict and their effect are often found late into the integration process. Consequently, this thesis tackles the need to simplify system integration and interoperability in order to reduce their associated costs and increase their effectiveness along with their efficiency. It is meant to bring new advances in the fields of system integration and system interoperability. Notably, by establishing a common taxonomy, and by increasing the understanding of system interfaces, the various aspects impacting system data exchanges, multi-architecture environment considerations, and the factors enabling interface governance as well as system reuse. To this end, two research objectives have been formulated. The first objective aims at defining a language used to describe system interfaces and the various aspects surrounding their data exchanges. Therefore, three key aspects are studied relating to system interfaces: the relevant language elements used to describe them, modeling system interfaces with the language, and capturing multi-architecture considerations. The second objective aims at defining a method to automate the software responsible for system data exchanges as a way of simplifying the tasks involved in system integration and interoperability. Therefore, model compilers and code generation techniques are studied. The demonstration of these objectives brings new advances in the state of the art of system integration and system interoperability. Notably, this culminates in a novel system interface description language, SIDL, used to capture system interfaces and the various aspects surrounding their data exchanges, as well as a new method for automating the system-level data-interchange software from system interfaces captured in this language. The advent of SIDL also contributes a new taxonomy providing a comprehensive perspective over system interoperability as well as a common language which can be shared amongst stakeholders, such as integrators, suppliers, and system experts. Being architecture-agnostic, SIDL provides a single architectural viewpoint overseeing all system interfaces and capturing multi-architecture considerations which was never achieved prior to this work. Furthermore, a SIDL code generator is introduced which has the novelty of generating the data-interchange software from a richer pool of information, notably from the high-level system relationships down to the low-level protocol and encoding details. Because multi-architecture considerations are captured natively in SIDL, this enables the code generator to be architecture-agnostic making it reusable in other contexts. This thesis also paves the way for future research building upon its contributions. It even proposes a vision for software application development with the end goal being to push further the boundaries of simplifying and automating the tasks involved in system integration and interoperability

Automated Validation of State-Based Client-Centric Isolation with TLA ⁺

Clear consistency guarantees on data are paramount for the design and implementation of distributed systems. When implementing distributed applications, developers require approaches to verify the data consistency guarantees of an implementation choice. Crooks et al. define a state-based and client-centric model of database isolation. This paper formalizes this state-based model in, reproduces their examples and shows how to model check runtime traces and algorithms with this formalization. The formalized model in enables semi-automatic model checking for different implementation alternatives for transactional operations and allows checking of conformance to isolation levels. We reproduce examples of the original paper and confirm the isolation guarantees of the combination of the well-known 2-phase locking and 2-phase commit algorithms. Using model checking this formalization can also help finding bugs in incorrect specifications. This improves feasibility of automated checking of isolation guarantees in synthesized synchronization implementations and it provides an environment for experimenting with new designs.</p

ICSEA 2021: the sixteenth international conference on software engineering advances

The Sixteenth International Conference on Software Engineering Advances (ICSEA 2021), held on October 3 - 7, 2021 in Barcelona, Spain, continued a series of events covering a broad spectrum of software-related topics. The conference covered fundamentals on designing, implementing, testing, validating and maintaining various kinds of software. The tracks treated the topics from theory to practice, in terms of methodologies, design, implementation, testing, use cases, tools, and lessons learnt. The conference topics covered classical and advanced methodologies, open source, agile software, as well as software deployment and software economics and education. The conference had the following tracks: Advances in fundamentals for software development Advanced mechanisms for software development Advanced design tools for developing software Software engineering for service computing (SOA and Cloud) Advanced facilities for accessing software Software performance Software security, privacy, safeness Advances in software testing Specialized software advanced applications Web Accessibility Open source software Agile and Lean approaches in software engineering Software deployment and maintenance Software engineering techniques, metrics, and formalisms Software economics, adoption, and education Business technology Improving productivity in research on software engineering Trends and achievements Similar to the previous edition, this event continued to be very competitive in its selection process and very well perceived by the international software engineering community. As such, it is attracting excellent contributions and active participation from all over the world. We were very pleased to receive a large amount of top quality contributions. We take here the opportunity to warmly thank all the members of the ICSEA 2021 technical program committee as well as the numerous reviewers. The creation of such a broad and high quality conference program would not have been possible without their involvement. We also kindly thank all the authors that dedicated much of their time and efforts to contribute to the ICSEA 2021. We truly believe that thanks to all these efforts, the final conference program consists of top quality contributions. This event could also not have been a reality without the support of many individuals, organizations and sponsors. We also gratefully thank the members of the ICSEA 2021 organizing committee for their help in handling the logistics and for their work that is making this professional meeting a success. We hope the ICSEA 2021 was a successful international forum for the exchange of ideas and results between academia and industry and to promote further progress in software engineering research

Arquitectura dirigida por modelos aplicada al desarrollo de metodologías de aprendizaje de idiomas

Hoy en día, cada vez más gente está interesada en el aprendizaje de una segunda -e incluso de una tercera- lengua extranjera. Esto es debido al fenómeno de la globalización, y está siendo facilitado por el uso extensivo de Internet. El proceso de aprendizaje de una lengua extranjera está definido por metodologías y -cada vez más- apoyado por la tecnología. El desarrollo de este tipo de aplicaciones es complejo (por la variedad de los entornos de ejecución, y por tener una gran cantidad de contenidos con frecuencia difíciles de validar), por lo que esta tesis propone un enfoque dirigido por modelos para desarrollo de software para dar soporte a la enseñanza de idiomas. El estudio y análisis de diferentes metodologías para el aprendizaje de idiomas ha permitido obtener, mediante un proceso de abstracción, los elementos comunes a todas ellas: En primer lugar (1) un conjunto/jerarquía de conceptos que se enseñan (contenidos), y (2) un conjunto de recursos (medios) para presentar los conceptos. Por otra parte, todas las metodologías definen (3) diversos tipos de ejercicios de aprendizaje (actividades) y (4) una secuencia o conjunto de secuencias que las relacionan (flujo de control/trabajo). Finalmente, definen una serie de (5) plantillas o disposiciones para la visualización de los contenidos y de las actividades (presentación). Esta tesis presenta una solución Model-Driven Architecture (MDA) que permite el desarrollo de aplicaciones para el aprendizaje de idiomas a partir de modelos. Así pues, desde una capa Computational Independent Model (CIM) hasta la capa Implementation Specific Model (ISM), se presentan los meta-modelos y los editores gráficos para los distintos lenguajes específicos de dominio, que permiten modelar todo lo necesario para el desarrollo de casi cualquier metodología de aprendizaje de idiomas. Por otra parte, en esta tesis también se definen las transformaciones necesarias, y el proceso de transformación asociado, para la generación automática del código fuente (en HTML y JavaScript) de aplicaciones de aprendizaje de idiomas. La propuesta ha sido validada a través del modelado y la generación del código fuente de los elementos de funcionalidad más importantes de la metodología Lexiway, así como de varios tipos de actividades de aprendizaje muy utilizados -y de forma muy parecida- en metodologías como Duolingo y Busuu

Experimental Evaluation of Growing and Pruning Hyper Basis Function Neural Networks Trained with Extended Information Filter

In this paper we test Extended Information Filter (EIF) for sequential training of Hyper Basis Function Neural Networks with growing and pruning ability (HBF-GP). The HBF neuron allows different scaling of input dimensions to provide better generalization property when dealing with complex nonlinear problems in engineering practice. The main intuition behind HBF is in generalization of Gaussian type of neuron that applies Mahalanobis-like distance as a distance metrics between input training sample and prototype vector. We exploit concept of neuron’s significance and allow growing and pruning of HBF neurons during sequential learning process. From engineer’s perspective, EIF is attractive for training of neural networks because it allows a designer to have scarce initial knowledge of the system/problem. Extensive experimental study shows that HBF neural network trained with EIF achieves same prediction error and compactness of network topology when compared to EKF, but without the need to know initial state uncertainty, which is its main advantage over EKF

Bioinspired metaheuristic algorithms for global optimization

This paper presents concise comparison study of newly developed bioinspired algorithms for global optimization problems. Three different metaheuristic techniques, namely Accelerated Particle Swarm Optimization (APSO), Firefly Algorithm (FA), and Grey Wolf Optimizer (GWO) are investigated and implemented in Matlab environment. These methods are compared on four unimodal and multimodal nonlinear functions in order to find global optimum values. Computational results indicate that GWO outperforms other intelligent techniques, and that all aforementioned algorithms can be successfully used for optimization of continuous functions

A Computational Framework for Resilience-Informed Design

It is desirable for complex engineered systems to perform missions efficiently and economically, even when these missions' complex, variable, long-term operational profiles make it likely for hazards to arise. It is thus important to design these systems to be resilient so that they will actively prevent and recover from hazards when they occur. To most effectively design a system to be resilient, the resilience of each design alternative should be quantified and valued so that it can be incorporated in the decision-making process. However, considering resilience in early design is challenging because resilience is a dynamic and stochastic property characterizing how the system performs over time in a set of unlikely-but-salient hazardous scenarios. Quantifying these properties thus requires a model to simulate the system's dynamic behavior and performance over the set of hazardous scenarios. Thus, to be able to incorporate resilience in the design process, there is a need to develop a framework which implements and integrates these models with design exploration and decision-making. This dissertation fulfills this need by defining resilience to enable fault simulations to be incorporated in decision-making, devising and implementing a modelling framework for early assessment of system resilience attributes, and exploring optimization architectures to efficiently structure the design exploration of resilience variables. Additionally, this dissertation provides a validity testing framework to determine when the resilient design process has been effective given the uncertainties present in the design problem. When each of these parts are used together, they comprise an overall framework that can be used to consider and incorporate system resilience in the early design process

Adaptive monitoring and control framework in Application Service Management environment

The economics of data centres and cloud computing services have pushed hardware and software requirements to the limits, leaving only very small performance overhead before systems get into saturation. For Application Service Management–ASM, this carries the growing risk of impacting the execution times of various processes. In order to deliver a stable service at times of great demand for computational power, enterprise data centres and cloud providers must implement fast and robust control mechanisms that are capable of adapting to changing operating conditions while satisfying service–level agreements. In ASM practice, there are normally two methods for dealing with increased load, namely increasing computational power or releasing load. The first approach typically involves allocating additional machines, which must be available, waiting idle, to deal with high demand situations. The second approach is implemented by terminating incoming actions that are less important to new activity demand patterns, throttling, or rescheduling jobs. Although most modern cloud platforms, or operating systems, do not allow adaptive/automatic termination of processes, tasks or actions, it is administrators’ common practice to manually end, or stop, tasks or actions at any level of the system, such as at the level of a node, function, or process, or kill a long session that is executing on a database server. In this context, adaptive control of actions termination remains a significantly underutilised subject of Application Service Management and deserves further consideration. For example, this approach may be eminently suitable for systems with harsh execution time Service Level Agreements, such as real–time systems, or systems running under conditions of hard pressure on power supplies, systems running under variable priority, or constraints set up by the green computing paradigm. Along this line of work, the thesis investigates the potential of dimension relevance and metrics signals decomposition as methods that would enable more efficient action termination. These methods are integrated in adaptive control emulators and actuators powered by neural networks that are used to adjust the operation of the system to better conditions in environments with established goals seen from both system performance and economics perspectives. The behaviour of the proposed control framework is evaluated using complex load and service agreements scenarios of systems compatible with the requirements of on–premises, elastic compute cloud deployments, server–less computing, and micro–services architectures