System Engineering Method for System Design

Industrial chemistr

A prescriptive approach to qualify and quantify customer value for value-based requirements engineering

Recently, customer-based product development is becoming a popular paradigm. Customer expectations and needs can be identified and transformed into requirements for product design with the help of various methods and tools. However, in many cases, these models fail to focus on the perceived value that is crucial when customers make the decision of purchasing a product. In this paper, a prescriptive approach to support value-based requirements engineering (RE) is proposed, describing the foundations, procedures and initial applications in the context of RE for commercial aircraft. An integrated set of techniques, such as means-ends analysis, part-whole analysis and multi-attribute utility theory is introduced in order to understand customer values in depth and width. Technically, this enables identifying the implicit value, structuring logically collected statements of customer expectations and performing value modelling and simulation. Additionally, it helps to put in place a system to measure customer satisfaction that is derived from the proposed approach. The approach offers significant potential to develop effective value creation strategies for the development of new product

Specification et implementation d'une architecture de signalisation a gestion automatique de la QdS dans un environnement IP multi domaines

The future Internet will have to transport the new application data with Quality of Service (QoS) guarantees. Then, it is necessary to redesign its architecture. In other respect, by definition, the Internet consists of several autonomous domains with their own QoS management mechanisms. This last point raises the question to carry the service continuity over all the domains. Then, to solve these two precedent problems the work presented in this thesis proposes a communication system providing guarantees of QoS in a multi-domain environment. This system is composed of both a communication plane and a signaling plane. The first one provides multi IP and Transport services when the second one manages the resources between the involved domains. Our contributions are the following ones. Firstly, we propose a model to characterize the IP and Transport services based on experiments over a national platform, ns-2 simulations and measurements performed over a DiffServ multi-domain emulation platform. Then, we upgrade a previous proposed communication architecture integrating this model to simplify the user task. Actually, the system is able to select automatically the appropriated Transport and IP services to satisfy the users. Secondly, we specify in UML and we implement in Java our signaling architecture providing the guarantee of the service continuity over all involved domains. Finally, we test, by the mean of two kinds of application, the complete system over a platform which emulates the behavior of several DiffServ domains.L'Internet du futur aura a transporter les donnees de nouvelles applications avec des garanties de qualite de service (QdS). De ce besoin resulte la necessite d'en re-concevoir l'architecture. Par ailleurs, la structure de l'Internet, compose de domaines independants vis a vis de la gestion de la QdS, pose le probleme de la continuite du service lors de la traversee de plusieurs domaines. Face a ces deux problematiques, la these soutenue est celle d'un systeme de communication offrant des garanties de QdS par flux applicatif dans un environnement Internet multi domaines. Son architecture integre un plan communication comportant plusieurs services/protocoles aux niveaux Transport et IP, et un plan signalisation assurant la gestion des ressources a la frontiere des domaines. Nos contributions sont les suivantes. Nous proposons un modele de caracterisation des services IP et Transport, etaye par : (1) des mesures realisees sur une plate forme nationale, (2) une etude en simulation (ns-2) et (3) des mesures realisees sur une plate-forme emulant (Dummynet) un Internet multi domaines. Nous etendons l'architecture de communication proposee dans des travaux anterieurs de facon a abstraire le niveau applicatif de la complexite du choix des services Transport et IP, et a optimiser l'utilisation des ressources du reseau. Nous specifions en UML et implementons en Java notre proposition d'architecture de signalisation permettant d'assurer la continuite du service offert aux applications sur tous les domaines traverses. Enfin, nous testons le systeme de communication avec deux types d'applications multimedias sur une plate-forme emulant le comportement de plusieurs domaines DiffServ

Spécification et implémentation d'une architecture de signalisation à gestion automatique de la QdS dans un environnement IP multi domaines

L Internet du futur aura à transporter les données de nouvelles applications avec des garanties de qualité de service (QdS). De ce besoin résulte la nécessité d en re-concevoir l architecture. Par ailleurs, la structure de l Internet, composé de domaines indépendants vis à vis de la gestion de la QdS, pose le problème de la continuité du service lors de la traversée de plusieurs domaines. Face à ces deux problématiques, la thèse soutenue est celle d un système de communication offrant des garanties de QdS par flux applicatif dans un environnement Internet multi domaines. Son architecture intègre un plan communication comportant plusieurs services/protocoles aux niveaux Transport et IP, et un plan signalisation assurant la gestion des ressources à la frontière des domaines. Nos contributions sont les suivantes. Nous proposons un modèle de caractérisation des services IP et Transport, étayé par : (1) des mesures réalisées sur une plate forme nationale, (2) une étude en simulation (ns-2) et (3) des mesures réalisées sur une plate-forme émulant (Dummynet) un Internet multi domaines. Nous étendons l architecture de communication proposée dans des travaux antérieurs de façon à abstraire le niveau applicatif de la complexité du choix des services Transport et IP, et à optimiser l utilisation des ressources du réseau. Nous spécifions en UML et implémentons en Java notre proposition d architecture de signalisation permettant d assurer la continuité du service offert aux applications sur tous les domaines traversés. Enfin, nous testons le système de communication avec deux types d applications multimédias sur une plate-forme émulant le comportement de plusieurs domaines DiffServThe future Internet will have to transport the new application data with Quality of Service (QoS) guarantees. Then, it is necessary to redesign its architecture. In other respect, by definition, the Internet consists of several autonomous domains with their own QoS management mechanisms. This last point raises the question to carry the service continuity over all the domains. Then, to solve these two precedent problems the work presented in this thesis proposes a communication system providing guarantees of QoS in a multi-domain environment. This system is composed of both a communication plane and a signaling plane. The first one provides multi IP and Transport services when the second one manages the resources between the involved domains. Our contributions are the following ones. Firstly, we propose a model to characterize the IP and Transport services based on experiments over a national platform, ns-2 simulations and measurements performed over a DiffServ multi-domain emulation platform. Then, we upgrade a previous proposed communication architecture integrating this model to simplify the user task. Actually, the system is able to select automatically the appropriated Transport and IP services to satisfy the users. Secondly, we specify in UML and we implement in Java our signaling architecture providing the guarantee of the service continuity over all involved domains. Finally, we test, by the mean of two kinds of application, the complete system over a platform which emulates the behavior of several DiffServ domainsINIST-CNRS (INIST), under shelf-number: RP 17272 / SudocSudocFranceF

A prescriptive approach to derive value-based requirements specification (application to the requirements engineering of commercial aircraft)

Ces dernières années, la conception de produit vise de plus en plus à remettre le client aucentre du processus de développement. De nouvelles méthodes et outils ont permis de formaliser nonseulement l identification des besoins et des attentes du client mais également leur transformation enexigences. Cependant, malgré les progrès récemment apparus dans ce domaine, la notion de valeurperçue par le client qui est associée au produit reste faiblement considérée durant le développement duproduit alors que la perception de cette valeur par le client va jouer un rôle clé au moment du choix duproduit.Dans cette thèse, nous proposons une approche normative visant l intégration de la notion devaleur du produit dans le processus d établissement des exigences. Un état de l art présente lesconcepts et les pratiques impliqués dans le déploiement de la fonction de qualité, étroitement liée auprocessus de spécification des exigences basé sur la valeur. Ces concepts sont relatifs aux notionsd objectifs, de modèles de la valeur, de fonctions d utilité multi attributs et de hiérarchie et de réseauxd objectifs.Notre approche se déroule en 4 étapes : (1) identifier et structurer les objectifs à partir del expression des attentes du client, (2) spécifier les attributs de la valeur perçue par le client etconstruire un modèle de la valeur client, (3) transformer les objectifs en exigences pour construire unmodèle global de la valeur produit et (4) dériver ce modèle global en un modèle de la valeur pourchaque composant du produit. Cette approche permet ainsi de prendre en compte explicitement lavaleur produit perçue par le client en l intégrant dans les phases de développement, ce qui favorise uneconception proactive dirigée par la valeur.Nous l illustrons sur un exemple d avion de ligne développé en Vanguard Studio. Cet exemplea été élaboré par l ensemble des partenaires au cours du projet Européen IST CRESCENDO et sert decas-test pour ce projetRecently customer-based product development is becoming a popular paradigm. Customer needsand expectations are identified and transformed into requirements in systematic processes for productdesign with the help of various methods and tools. However, in many cases, these approaches fail tofocus on the perceived value that is crucially important when customers make the decision ofpurchasing a product. The requirements specification derived from these approaches are typicallyvalue-implicit.In this thesis, a prescriptive approach to derive value-based requirements specification is proposedby integrating the concept of value into the house of quality of quality function deployment. Anintegrated set of theories, methods and concepts is introduced in order to mitigate the sevenmethodological problems of house of quality regarding to establishing appropriate value-basedrequirements specification. The foundations of the approach include concepts of objective, valuemodel and consequence model, methods of means-ends objectives network, fundamental objectiveshierarchy, response surface methodology and value-driven design, and theory of multi-attribute utilitytheory. The procedure of the approach is a four-step process: (1) identify and structure objectives frominitial customer statements of expectations, (2) specify attributes and construct customer value model,(3) transform fundamental objectives into engineering characteristics to construct system value model,and (4) derive component value models from system value model. Through this procedure, initialcustomer statements can be reasonably derived into customer value model, system value model andcomponent value model. The benefits of the approach are that it enables (1) reasonably qualifying andquantifying customer value, and performing value modeling and simulation, (2) perceived customervalue being subsequently used reactively for design evaluation, and proactively for value-drivendesign.The approach is applied in the context of a European Community s R&D project CRESCENDO tohelp constructing airlines group value model for commercial aircraft development. This applicationfocuses on the first two-steps of the approach, and the value models are implemented in businesssoftware Vanguard StudioTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF

Multicriteria Decision-Making Methodology for Systems Engineering

International audienceA multicriteria decision-making methodology is proposed for decision making in systems engineering. A process is proposed for generating weights for evaluation criteria needed to evaluate design alternatives. A decision-maker classification is proposed based on the roles they play during the decision process. In order to accomplish this, in the first step, stakeholders' categorization is made, and their corresponding weights are determined representing their stake in decision. In the next step, each stakeholders' preference over the criteria set is determined, which leads to the ordinal rankings of the criteria for each stakeholder. In the following step, the stakeholders' criteria ordinal rankings are transformed into cardinal weights using the different decreasing utility functions. Thus, obtained final criteria weights are used for evaluation of the alternative design solutions. Optimality check measures are devised to select the appropriate decreasing utility functions

The Advantages of Systems Engineering Standards, a Case Study of Application of the EIA632 Standard to Design of a Small-Scale Yacht

International audienceThe objective of the work described in this article is to demonstrate the advantages of using recommended methodology standards for the development of complex systems. After first describing the principles of systems engineering this paper then presents a universal systems engineering standard and describes how it was used to design and build a small-scale yacht. This case study demonstrates how the standard is an effective methodological support and allows an early detection of possible weaknesses during initial design stages

Replacing target setting by value models in the ‘house of quality’ for value-based requirements specifications

Setting targets for engineering characteristics (ECs) is common practice in the ‘house of quality’ for establishing requirements specifications. However, if deployed arbitrarily, this practice is prone to errors and can often yield irrational results. Three potential methodological problems have been identified, regarding the setting of independent targets for each EC, setting fixed targets, and cascading down targets from the system level to the component level have been identified. In this paper, targets are categorized as constraints and goals because of their different implications for value trade-offs. Then, a ‘multi-attribute utility theory’ based approach is proposed, in which a system value model is developed in order to replace the setting of targets for system ECs and component value models are further derived to replace the setting of targets for component ECs. These value models enhance the traditional approach to requirements specification so that value-based requirements specifications can be developed. A case study is deployed to demonstrate the applicability of the approach in the civilian aerospace context for the development of requirements for commercial aircraft. The benefits of the proposed approach are twofold: a) value becomes an explicit construct, and b) value can be rationally modelled and simulated in the ‘house of quality’ in order to establish value-based requirements specifications. Furthermore, identified methodological problems in terms of setting EC targets at any level are mitigated