REVISITING THE SIMILAR PROCESS TO ENGINEER THE CONTEMPORARY SYSTEMS

J Syst Sci Syst Eng (Sep 2010) 19(3): 321-350ISSN: 1004-3756 (Paper) 1861-9576 (Online)DOI: 10.1007/s11518-010-5144-8CN11-2983/NREVISITING THE SIMILAR PROCESS TO ENCINEER THECONTEMPORARY SYSTEMS*Ana Luisa RAMOS'Jose Vasconcelos FERREIRA'Jaume BARCELO2'GOVCOPP- Department of Economics, Management and Industral Engineering, Universiy ofAveir, Portugalaramos@ua.pt (8)josev@ua.pt'Department of Statistics and Operations Research, Technical University ofCatalonia, Barcelona, Spainjaume.barcelo@upc.eduAbstractThis paper addresses the present-day context of Systems Engineering, revisiting and setting up anupdated framework for the SIMILAR process in order to use it to engineer the contemporary systems.The contemporary world is crowded of large interdisciplinary complex systems made of other systems,personnel, hardware, software, information, processes, and facilities. An integrated holistic approach iscrucial to develop these systems and take proper account of their multifaceted nature and numerousinterrelationships. As the system's complexity and extent grow, the number of parties involved(stakeholders and shareholders) usually also raises, bringing to the interaction a considerable amountof points of view, skills, responsibilities, and interests. The Systems Engineering approach aims totackle the complex and interdisciplinary whole of those socio-technical systems, providing the meansto enable their successful realization. Its exploitation in our modern world is assuming an increasingrelevance noticeable by emergent standards, academic papers, international conferences, andpost-graduate programmes in the field. This work aims to provide“the picture" of modern SystemsEngineering, and to update the context of the SIMILAR process model in order to use this renewedframework to engineer the challenging contemporary systems. The emerging trends in the field are alsopointed-out with particular reference to the Model-Based Systems Engineering approach.Keywords: SIMILAR process, systems engineering, standards, MBSE1. Introductionemergent properties, the lifecycle, and theSystems Engineering (SE) is concerned withrequirements of the system. The SIMILARthe“big picture", the whole, the interrelation-process model (Bahill & Gissing 1998)ships, the synthesis, the interdisciplinarity, thedescribes the 'recipe' or the set of interacting SE中国煤化工*This work was partially supported by the Portuguese Foundal.MYHCN M H G&Y (FCD, DoctralGrant SFRH/BD/43892/2008.⑥Systems Engineering Society of China and Springer-Verlag Berlin Heidelberg 2010Ramos et aL: Revisiting the SIMILAR Process to Engineer the Contemporary Systems322J Syst Sci Syst Engactivities which transform the inputs into outputsenvironments, facilitate the interoperabilitythat is, which generate a successful system. Thebetween people and organizations, the sectionSIMILAR acronym stands for State the problem,three revisits the SIMILAR process model,Investigate altermatives, Model the system,describing its key characteristics and proposingIntegrate, Launchthesystem, Assessan updated integrative framework to use thisperformance, and Re-evaluate.universal process, based on the ISO SEIn 1998, Bahill and Gissing had suggest thisprocesses standard, the fourth section provides ageneral process as a universal way of planningdescription of the SE foremost emerging trendsand problem solving closely related to humanwith particular emphasis on the Model-Basedthinking. After a decade, the process stillsSystems Engineering (MBSE) approach. Thisextensive and straightforward but must beemerging paradigm relies on the application ofcontextualized in the framework of themodeling principles, methods, languages andintermational SE process standards that havetools to the entire lifecycle of large, complex,emerged since then. Furthermore, its adequacyinterdisciplinary, socio-technical systems and itto tackle the development of the contemporaryis expected to play, in the next decade, ansystems, which are typically large, complex,increasing role in the practice of systemssocio-technical, interdisciplinary Systems-of-engineering. The last section describes theSystems (SoS), has to be evaluated.on-going work related with the IUTEO systemThis work constitutes an attempt todevelopment and points out some majorrediscover this simple, intuitive, and integratedconclusions.process model at the light of the modermintermational ISO/IEC 15288 standard (“Systems2. Systems Engineering Essentialsand software engineering - System lifecycleThe system is the essence of SE. Despite theprocesses") that suffers from some excess ofinnumerous definitions of system (Bahill et al.flexibility and some lack of“glue".2002, Hitchins 2003, Meadows 2008), all theIn order to test the adequacy of the proposedauthors share the same key idea: elements +framework to develop the moderm, large,interactions = whole. The elements or parts cancomplex，interdisciplinary SoS, it is beinginclude people, software, hardware, facilities ordeveloped the Intelligent Urban Traffic 8documents, and are the relationships among theEnvironment Operations (IUTEO) system thatparts that impel unique emergent properties.the authors believe being representative of theThis principle of emergence, along with thesystems-of-interest for the field of Systemsprinciples of organismic analogy, holism andEngineering.synthesis, constitute the basic tenets of theThis paper is organized as follows: thesystems approach or systems thinking (Hitchinssecond section describes the essentials of SE2007). This philosophy, opposite to the classicalproviding a brief review on its main issues, andanalytical Cartesian reductionism, has guide theemphasizing the evolving technical standards inway 1中国煤化I eneral Systemsthe field that, in emerging collaborative worldTheot|YHC NMH G the SystemsRamos et aL: Revisiting the SIMILAR Process to Engineer the Contemporany SystemsJ Syst Sci Syst Eng323Science.old Systems Engineering" (or the traditional, theThis relatively new branch of Scienceclassical, the ordered) and“the new Systems(Bailey 2005) is devoted to the open systems, toEngineering"(Rhodes 2008， Sheard &the wholes, and to the emergence, importingMostashari 2009)。 This evolution has beenmultidisciplinaryinputsfrombiology,reflecting predominantly the nature of themanagement, psychology, mathematics, ansystems to engineer, which in turn reflect thspreading its outputs through several fieldstremendous and continuous advances in theincluding systems engineering, cybernetics, andtechnological and societal fields.general philosophy (Davidz & NightingaleThis emerging meta field of study, in a2008). .synergistically co-evolution with SE and aimingThe Systems Engineering field can beto add a broader context to the field, is calledconsidered as a branch of Systems Science withEngineering Systems“a field of study taking ana strong contribution of Engineering, resulting inintegrative holistic view of large scale, complex,a field devoted to the creative application oftechnologically- enabled systems with significantscientific principles to the design andenterprise level interactions and socio-technicaldevelopment of systems by means of a systemsinterfaces" (Rhodes 2008). There are some otherapproach. The definitions of SE (Wymore 1993,references which name these new tendencies asEisner 2002, Tien & Berg 2003, Ramo 2004,Complex Systems Engineering (Sheard &INCOSE 2007a), which began to be formalizedMostashari 2009), Engineering of Complexityin the 1970s with the first U.S. military(Honour 2008)， and Systems of Systemsstandards, are diverse but, in fact, they all reflectEngineering (Jamshidi 2008, Lane & Boehmthe essential concepts of the systems approach2008).like holism, synthesis, and interrelationships, asThe classical systems(thesystem-as-well as the engineering project-based ideas ofmachine paradigm) were small to large scale,system lifecycle and requirements. Sheard &multidisciplinary,relativelystableandMostashari (2009) synthesize the definitions inpredictable, without people as component, andone inspired expression “one could imagine awere typically from the aerospace and defensescience of relationships underlying systemsindustries. The new ones (the system-as-engineering".organism paradigm), which must cope with theglobal challenges of sustainable development,2.1 Overvieware large-scale, complex, adaptive, interoperable,Undoubtedly, SE is concemed with the bigscalable,technology-intensive,humanpicture, the whole, the interrelationships, theintegrative and comprise, for example, the sosynthesis, the interdisciplinarity, the emergentcalled“super-systems" like transportation andproperties, and the lifecycle of the systems but,sustainable energy (Hybertson & Sheard 2008).what kind of systems are under consideration?The. perspectives of the different shareholdersSurprisingly, in a relatively recent and evolvingan中国煤化工cnficting andfield as SE, there are already references to“thecom:RYHCNMHGandresolvedtoRamos et al: Revisiling the SIMILAR Process to Engineer the Contemporary Systems」Syst Sci Syst Engserve the highest order system-of-interest needsmanager, coordinator and technical manager(Rhodes 2008).(Sheard1996).The currentcomplexSo, considering the 21st century, thesocio- technical challengesdemand morechallenge to undertake is the large scale (with acompetences to connect people, to tacklelarge number of constituents, interrelationships,modeling tasks, and to cope with variety, holism,variables,uncertainties and nonlinearities,flexibility, scalability, and risk. A gooddecentralized in nature and broad in scope),mathematicalbackgroundandstrongsocio-technical (with technical works involvingmanagement and communication skills arepeople as inberent parties of the system withtypically mandatory requirements to do the jobsignificant social participation, interest, and(Sheard 1996). The technical competences, theconcemn, governed by organizational policiesleadership and versatility, the capacity foand rules, and externally controlled by nationalsystems thinking and to solve problemslaws and regulatory policies (Maier & Rechtincreatively are also part of the profile. Haskins2002，Sommerville 2007))， complex (with(2007) refers to Borhaug who characterizes theautonomousheterogeneouscomponents,'ultimate systems engineer' as“a leader anddisplaying emergent macro-level behavior,curious person with strong will, long sightedself-organizing and adaptive (Sheard &eyes, fast moving legs, long reaching arms,Mostashari 2009)), SoS (man-made systemscoordinated by a systematic and strategic brain".with managerial and operational independenceof the component systems (Lane & Boehm2.2 Technical Standards2008), which have individual lfecycles and areA technical standard is an established normtypically autonomous commercial ofF the-shelfwhich allows the unified utilization of criteria,(COTS) systems).terminology, methods, processes, measures,The systems engineer is the responsible toframeworks, tools, etc. The standards areput things together, being the interface betweenunifying references necessary to institutionalizemanagers, customers, suppliers, and the differentthe practice of a given discipline, helping tospecialty engineers that make part of the processtranslate the technical perspective to a moredevelopment. These are usually dedicated tobusiness one, helping to clarify its relevance tospecific aspects of the system whereas thesociety, and to meet future challenges (Arnoldsystems engineer is concerned with the2007). Furthermore, andn emergentintegration of the pieces into a unified coherentcollaborative world environments, they facilitatewhole, the higher- system, during its entirehe interoperability between people andlifecycle. The success of this system depends onorganizations. The standardization is somehow athe 'winning perspective' of the criticalmeasure of the maturity, widely expansion andstakeholders.growing acceptance of a given field and, in thisThe traditional main roles of the systemssense, Systems Engineering is still a newbornengineer include: system designer, system中国煤化工definitions andanalyst, requirementsowner,information:fYHCNM H G.Ramos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystermsJ Syst Sci Syst Eng325The core set of SE standards is relatively new,SE. They are harmonized to be used by the twowith less than a decade, and is currently infields and they underline the need to integrateintense development by the Standards Technicalsystems and software engineering processes,Committee of the International Council onalong with hardware and human engineeringSystemsEngineering(INCOSE),heprocesses (Bochm 2006). These growingSubcommittee Sevenof theInternationalintegration needs are mainly due to thOrganization for Standardization (ISO)， theincreasing criticality of software within systemsInternational Electromechanical Commissionand to the increasing emphasis on user intensive(IEC), the Institute of Electrical and Electronicssystems and value generation.Engineers (IEEE), and the Object ManagementThe non ISO major standards (IEEE 1220:Group (OMG).“Application and Management of the SystemsThe first standards in the SE field have risenProcess", from 1998， andfrom the American military and aerospaceANSI/EIA 632: “Processes for Engineering aindustries, in the 1970s and 1980s, and wereSystem", from 1999， American Nationaldedicated to the engineering process or, in otherStandards Institute/Elctronic Industries Alliance)words, to the “WHAT”activities are to beare also aligned with ISO/IEC 15288. Theperformed. A process is a set of interrelatedINCOSE has also announced the commitment toactivities which transform inputs into outputsadopt this international standard, which is(Cloutier & Verma 2007). Since then, there hasreflected in its SE Handbook most recentbeen an effort to take these standards to beversion (INCOSE 2007a).domain independent in order to be applicableBesides theprocess standards, theacross different sectors, and to be international.fundamental core that provides a foundation forThe process standards still constitute thea SE approach, there are other standards in thepredominant core of norms, being the ISO/IECfield. The Architecture Frameworks (AF) is one15288:“Systems and software engineering -of those groups, which includes the standardSystem lifecycle processes", ftom 2002 (revisedframeworks that have been developed to supportin 2008), the most relevant updated internationalsystems' (and software) architecting. Accordingbenchmark. Despite the initially independentto Cloutier & Verma (2007), a framework is aand sequential evolution of the two fields, thelogical structure or an organizational skeletonSE processes share much of their contents withused to classify concepts, terminology, data,software engineering practices and they presentartifacts，etc. This tool, for structuring anan increasing interaction which is reflected inintegration, provides generic guidance forthe moderm standards like the CMMI (Capabilitydesigning the architecture of a system that is,Maturity Model@ Integration, 2000, from thethe fundamental organization of a system,Camegie Mellon Software Engineering Institute),embodied in its components, their relationshipsthe ISO/IEC 12207 for SW engineeringto each other and the environment, and the("Systems and software engineering - Softwareprinci中国煤化工and evolution”lifecycle processes") and the ISO/IEC 15288 for(IEEEMHCNMHGofthesystemRamos et al: Revising the SIMILAR Process to Engineer the Contemporary Systems326J Syst Sci Syst Engarchitect and the value of an architectural‘Zachman Enterprise Framework2TM’ wasapproach are also emphasized by Chen &released. The enterprise architecting group alsoClothier (2003) and Maier (2006) that refer thatincludes the 'TOGAF' framework (The Openarchitecture is one of the key elements ofGroup Architecture Framework) and the 'FEAF'modern SE being the base step towardframewotk (Federal Enterprise Architectureconceptual integrity.Framework). The first one introduces a methodBrowning (2009) provides an excellentfor the developmentof the enterprisedescription of AF and describes them as garchitecture (ADM Architecture Developmentcollection of integrated and synchronized viewsMethod) and the second one, closely alike thededicated to describe a complex system. EachZachman framework, is more focused on capitalview is a repository of subsets of informationmanagement and citizen services' improvement.which addresses particular needs, of particularIn the 1990s the former principles of thegroups, in order to support different perspectives, Zachman ftamework were extended, by thepurposes, tasks and design decisions. The mostdefense industries, to several different areas likepopular standard in this topic, the IEEE 1471,Command,Control,Communications,2000(IEEE RecommendedPractice foComputers，Intelligence, Survillance, andArchitectural Description of Software IntensiveReconnaissanceoriginatingtheC4ISRSystems) includes principles more tailored toframework'. This framework evolved into thesoftware development but the ISO is working oncurrent U.S. Departmentof Defensethe adoption of this norm as an internationalArchitectureFramework'DoDAF'，whichstandard and on its revision to include system'sinvolves a broader scope of systems and SoSarchitectural description and not just softwareThese ones, typically from the military/defenseintensive architectures. The core idea behind thisdomain, engage complex integration andstandard relies on the utilization of models tointeroperability issues.describe the architecture of a system.The framework relies on a Core ArchitectureThere are several established AF typicallyData Model which defines the database schemaoriented for a given target domain. Theto gather shared works, and encloses four mainenterprise architecting, the systems architectingtypes of views, the All View (AV), theand the software architecting are the classicalOperational View (OV), the Systems View (SV),contexts (Browning 2009). The best well knownand the Technical Standards View (TV), whichAF is perhaps the ‘Zachman framework'entail, in the totality, 29 perspectives of an(Zachman 1987), which presents a high-levelarchitecture. Each view has particular artifacts tological construct to control the interfaces and todescribe the atributes of the model. The DoDAFintegrate all the components of an informationhas a similar version fom U.K, developed bysystem,in 1997,framework wasthe Ministry of Defense, the 'MoDAF"', whichreengineered to tackle the modern concept ofadds a strategic view and an acquisition view.Enterprise Modeling: the 'Zachman FrameworkBot中国煤化工e references tofor Enterprise Architecture', and in 2008 the theYHC N M H Gmore tailored toRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJ Syst Sci Syst Eng327systems architecting. According to Richards,methodologies like, for example, the Harmony,Shah et al. (2007) the enterprise architectingthe Object-Oriented Systems Engineeringlinks the organizational goals to the businessMethod (OOSEM), the Rational Unified Processactivities while the systems architecting relatesor Systems Engineering (RUP SE) or theoperational concepts andcompetences toObject-Process Methodology (OPM), constitutetechnical architectures.examples of these emerging paradigms that are,The 4+1 View Model of Architecture ?in their essence, MBSE methods.(Kruchten 1995) is a typical AF for modelingThe Modeling tools can be classified assoftware architecture.It provides fouranother group of Systems Engineering standards.concurrent views, the logical, the process, theThis group includes the common representationsimplementation, and the deployment ones,used to describe a system. The Functional Flowwhich are integrated by a fth view, the useBlock Diagrams (FFBD), developed in thecase/scenarios view. Each view addresses1950s, have been, for many years, the classicalspecific perspectives and concerns of therepresentation of SE with a wide spread ussoftware intensive system being the models ofwithin the community. This tool illustrates a stepthe Unified Modeling Language (UML) anby step sequence of a system's functional flowexcellent artifact to describe these views. Thethrough a functional decomposition approach.'Model Driven Architecture' (MDA9), launchedDuring the 1970s, the Structured Analysis andin 2001 by the OMG can also be considered as aDesign Technique (SADTTM) emerged as thesoftware architecture. This initiative, particularlygraphical language for communicating ideasconcerned with interoperability issues, bases the(Ross 1977) and to understand and describeexecutable software architecture in UML (orsystems as a hierarchy of functions.other OMG) models. An abstract computerIn 1993 the National Instute of Standardsindependent model (CIM) is the base to developand Technology (NIST) launched the IDEFOa platform independent model (PIM) that is then(Integration DEFinition for Function Modeling),transformed into a platform specific modela graphical notation belonging to the IDEF suite(PSM) that is transformed into code such as Javaof modeling approaches and derived from theor C# (Arlow & Neustadt 2005). The main ideaSADT. This notation was developed to representis to separate the business logic from theactivities or processes that are carried out in anunderlying technology platform.orderly manner (Kim et al. 2003), ilustrating theIn addition to the formal process standardsfunctional perspective of a system, the data flowand architecture frameworks， there is aand the system control.collection of informal methodological principles.These traditional functional decompositionThe group of the SE methods, the“HOW" toprocedures/representations are nowbeingperform the activities, is not contemplated by“replaced" by objct-oriented approaches. Theofficial standards but, as Friedenthal et al. (2008)OMG has developed the UML, the standardstate, they will emerge as they prove their valuemode中国煤化工: development,over time. These methods, and the associatedandHC N M H Gngineering hasRamos et aL: Revisiting the SIMILAR Process to Engineer the Contemporary Systems328JSyst Sci Syst Engbeen released in 2006, the Systems ModelingFinally, the data and model interchangeLanguage (SysML). This graphical language,standards support data and model exchangewhich supports the specification, analysis,among tools. The UML based modelingdesign, and verification of complex systems, islanguages have a common foundation known asconsidered as the next de facto modelingOMG Meta Object Facility (MOFTM) (also anlanguage for SE. The UPDM (Unified ProfileISO standard ISO/IEC 19502: 2005)， anfor DoDAF/MoDAF) is also an extension oextensible integration framework for defining,UMLto describe SoS and enterprisemanipulating and integrating metadata (the dataarchitectures compliant with DoDAF andwhose purpose is to describe other data) andMoDAF requirements.This profile isdata in a platform independent manner. Theparticularly tailored for military acquisitionXMI (XML Metadata Interchange) specification,programs. The Object Process Diagram (OPD)also from OMG (and also an ISO standardand the Object Process Language (OPL) are,ISO/IEC 19503: 2005), enables the interchangerespectively, the graphical and textualof metadata between UML-based modeling tools,representations used by the OPM.like UML or SysML, and MOF-based metadataThe categorization of the standards describedrepositoriesitdistributedheterogeneousabove, as well as of others that will be referredenvironments, through the XML (eXtensiblein the following paragraph, is depicted in FigureMarkup Language). This language, which1. This taxonomy is based on the classificationdescribes a class of data objects known as XMLproposed by Friedenthal et al. (2008) but isdocuments, is mainly used to store and transportrearranged and extended according to ourdata over the Internet.perspective.ISO/IECPROCESSESMIL-STDMIL-STD 1 IEEE 1120ANSIEIA-15288499A490AEIA- 731.1CMMI‘EnterpriseSytemsSofnwareARCHITECTURETOGAFFEAF: DoDAFMoDAF4+1 !MDAFRAMEWORKSZachmanMETHODOLOGIESOOSEMRUP_SEHarmonyOPMMODELLINGFBBDSADTIDEFOSysML| OPDOPIL台TOOLS&DATA/ MODELMOFXMIISO 10303 - AP233INTERCHANGEFigure 1 Taxonomy for Systems Engineering standards and ma中国煤化工erent categories(adapted from Friedenthal, Mo:YHCNMHGRamos et aL: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJ Syst Sci Syst Eng329Probably, the most relevant and inclusivestakeholders. The systems engineer muststandard in this area will be the norm STEPorchestrate the technical aspect, involving all the(Standard for the Exchange of Product modelrequired experts for maximum performance, thedata)ISO 10303-AP233 (Industrial automationbusiness aspect, ensuring that all the valuablesystemsandintegration:Product dataopportunities are taken, and the budget aspect,representation and exchange-Part 233: Systemsidentifying and mitigating all the significantengineering data representation). Still underrisks (costs and schedule constraints). The triaddevelopment, this standard is a modular vendorof cost, schedule, and performance (cheaper,neutral format for interchange of systemsfaster and better) constitutes the emblematicengineering data and to support interoperabilityobjective of almost every stakeholder.among tools. The Application Protocol 233According to the ISO/IEC 15288 standard,covers the entire SE lifecycle consideringthe lifecycle of a system encompasses six mainrequirements，functional modeling, behavioralstages namely: i) concept, i) development, ii)modeling, etc. For example, an IDEFO activityproduction, iv) utilization, v) support, and vi)diagram can be exported as AP233 andretirement. The Concept stage aims to assessre-imported as a SysML activity diagram.new business opportunities, to explore concepts,These (formal/informal) standards constituteo identify the stakeholders'needs andthe core set of norms that have been driven therequirements, and to propose viable solutions;development of SE. This standardization ishe Development stage intends to refine thecrucial to advance the field and to establishrequirements, to create a description of thebenchmark practices across different domains.solution, to build the system, and to verify andvalidate it; the Production stage has as purpose3. Revisiting the SIMILAR Processthe production of the system and its inspectionThere is no universal 'recipe' to do Systemsand test; the Utilization stage aims to operate theEngineering. Since every system is unique andsystem in order to satisfy the users' needs; thehe characteristics of its users， suppliers,Support stage provides sustained systemmanufacturers, and operators are so diverse, thecapability, and the Retirement stage isSystems Engineer tailors his/her favoriteresponsible for store, archive, or dispose theprocesses to satisfy the needs of a given projectsystem,(Buede 2009). The process defines WHATThe literature provides several traditional SE .activities are to be performed with no details onprocess models which have been based on thehow to perform them.standards previouslypresentedlike theThe activities to perform are naturally relatedANSIEIA 632 and the CMMI. Some of thosewith the lifecycle stages. The definition of amodels are quite burden and complicated whilelifecycle, with corresponding control/decisionothers are more manageable and, from our pointgates, establishes a framework to develop aof view more easilv_ tailored to the uniquenesssystem's solution, in an orderly and efficientlyofe中国煤化工ms Engineeringway, which accomplishes the needs of theProcYHc N M H Ghan's SystemsRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems330J Syst Sci Syst EngEngineering Process Model, and the SIMILAR1998)，and gathering the consensus of aProcess are perhaps the most referred models inrepresentative group of senior system engineers,the field (Bahill & Gissing 1998, Martin 2000;the SIMILAR process (Figure 2) constitutes ourBuede et al. 2002, INCOSE 2007a). It is alsopreferred process approach. Nevertheless, andcommon to found some variants from the DoDfor the reasons previously mentioned, it is quiteand the NASA.important to straighten out worldwide norms andWith more or less details, these roadmapto adopt international SE process standards.models share the obvious relation with theThe SIMILAR Process is an abstractionlifecycle stages, and a series of iterativewhich reflects a logically consistent andhigh-level activities, namely: (i) to know whateffective means of planning and problem solving.the customers want and to define the systemsThe acronym stands for State the problem,objectives; (i) to define and manage systemInvestigate alternatives， Model the system,requirements and to establish the functionality;Integrate,Launch thesystem, Assess(li) to identify and minimize risk conductingperformance, and Re evaluate. As their authorstrade studies as a basis for informed decisionstate, this process is quite “universal" and amaking; (iv) to evolve design and operationconsiderable number of well known processesconcepts; (v) to plan and integrate the work; (vi)from diverse fields can be mapped to thetoenhance communication andsystemSIMILAR process. The authors also remind thatunderstanding; and (vi) to verify that the systemthe linear appearance of the model does notmeets customers' needs.represent a sequential procedure. The functionsThe international standardize version of theare performed in a parallel and iterative manner.SE process, established at the ISO/IEC 15288,The Figure 3 depicts the ISO/IEC 15288 SEoutlines the areas of concern for SE but does notprocesses mapped to the elected SIMILARdetail the process to do the work, giving someprocess, as well as the main lifecycle stagesflexibility to pick the right processes for a givendefined at the intemnational standard, and a seriessituation but suffering, from our perspective, ofof several processes and factors that are traversalsome lack of“glue". Being a simpler, intuitive,to the entire lifecycle and that can beintegrated, and guided model, more closelyaccommodated into three major categories, asrelated to human thinking (Bahill & GissingproposedbyMartin(2000): ProjectState heInvestgaleModel theIntegrateLaunchhe -+-pAsessOutputsProbem. AtemalvesSystemSyslemPertormance↑~↑. Reovaluate'I ReevauateReevaluate| Re evaluateRevauate. Reevauate中国煤化工Figure 2 SIMILAR process model (sourciMYHCNMHGRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystermsJSyst Sci Syst Eng_331ISOTEC 15288 SE ProcessesSIMILAR ProcessTechnical Proceses Projcet Proceses Enterprise Processes Agreement ProcessesSlate the problemnStakch. Req Der.lnning. Enterp, Fav. ManagCocept. Req. Analyis。SysL LCy Pro. ManInvestigate altermatives。Architecural Design . Decision-makingMianagement。AcquisitionDevelopmentModel the system。lmplementation。Risk ManagementIntegrate. VerificationMangetientProductionLaunch the system: ValidationManapemnenManagement. SupplyUilizationSupport{ Assess performance. Maintenance. Asessment. Quality ManagementRetirenert Re evaluate. DisposalConunolProject EnvironmentEnterprise EnvironmentExternal EnvironmentTeamI workPolicies &SocialPropemnentssosProcedures人( ; udelieRegultins resopsilitismanag“ProjectleamedCompatingMetris: peformang, costspecialies and ToolsCiltureFigure 3 ISO/IEC 15288 processes mapped to the SIMIL AR process and traversal processes/factorsEnvironment, EnterpriseEnvironment, andrelevant to the realization of a system. TheExternal Environment. This mapping is anidentification and exploitation of intermal andattempt to integrate the two models in oneexternal interfaces are crucial objectives of theseconsistent description of the SE process. Theprocesses providing the context of the businessISO processes were allocated to the SIMILARenvironment. The Agreement Processes conductfunctions where they assume more relevance. Asthe focal business of the organization: theobvious, is a subjective interpretation and can bebuying and selling of goods or services. All ofadapted to a particular case through any otherthese processes are supported by other traversalarrangement.tasks and enabler/disabler factors that make partThe four right columns represent the fourof the Project Environment (e.g， Projectprocess categories defined in the standard. TheManagement, Team Work, Writing LessonsTechnical Processes are used to identify theLearned)，the Enterprise Environment (e.g.,requirements which constitute the basis of thePolicies & Procedures, Available Technologies)efforts to create the system, to sustain the systemand/or the External Environment (e.g, Laws &throughout its useful life, and to support theRegulations, Social Responsibilities).disposal of the system. The Project Processes areThe following description summarizes theessential to general management activities andmajor aspects of the SIMILAR Processrelevant to the technical coordination of afunctions along withhefundamentalproject. The Enterprise Processes focus on thechar;| 中国煤化工ISO/IEC 15288capabilities of the organization which areinter:YHCN MH Gorocesses. ThisRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems332J Syst Sci Syst Engperspective is based on the works of Bahill &world solution can be built) requirements;Gissing (1998), Bahill & Briggs (2001), Bahillsummarize the four most important metrics:et al. (2002), INCOSE (2007a), and on theperformance, cost, schedule, and risk; andauthors' points of view. The other standardexpress the Concept of Operations (ConOps).processes, which correspond mostly to strategicThese elements should be cleared andand management functions, will not bunambiguously expressed in words or as models.described in this paper. Nevertheless, they areThe OPD for the function State the problem iscritical to SE and to the successful realization ofdepicted in Figure 4.a system.The main inputs are the stakeholders' needs,Since a process consists of a series ofwhich rule the development of the project. Theinteracting activities that transform inputs intostakeholders (individuals or organizations) areoutputs, the description will be based o1parties with legitimate interests in the system.diagrams containing the major activities of theThey can be classified as end-users, operators,function in analysis, along with the main inputs,owners, enterprise decision makers, regulatorythe enabler and controller mechanisms, and theagencies, sponsors, support organizations, andoutputs. These diagrams are OPDs (Objectsociety at large. Sometimes they are not directlyProcess Diagrams) from the OPM (Dori 2002).involved but they are represented by otherThe modeling language corresponding to this SEorganizations. The project constraints, in termsmethodology is fairly simple and intuitive, andof budget, schedule, risk, and technical solutionsthe authors decided to use it to describe the(for example, legacy systems) are also inputs toactivities of the SE process.state the problem. The terms and conditions ofcertain agreements, the project processes, th3.1 State the Problembusiness statutes and regulations, and thThis function starts with the identification ofsocietal laws are controller mechanisms whichthe "reason to do" followed by the high-levelcan restraint the problem definition. Thedescription of the main functionalties of theenterprise organization, infrastructure, policiessystem (what the system should be able to do inand processes can act as enablers favoring (orits operating environment) with all of thenot) the successful statement of the problem.requirements that must be satisfied. TheThe major outputs， typically documentsfollowing list includes the typical activitiesandor models, include the ConOps document,performed at this level: state the problemthe approved system requirements, the measuresdefining a vision and a mission; identify all theof effectiveness and suitability that will be usedstakeholders; understand customers' needs andforassessing the developed system, thexpectations; elicit andmanagesystemarchitectural constraints that will limit threquirements; verify(ensuringthat eachinvestigation of altermnatives, and a matrix ofrequirement has been satisfied) and validaterequirements'verification and traceability(ensuring that the requirements are correct,(RV中国煤化工ents how thecomplete, consistent and attainable that is, a realrequYHCNMHGttheRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems」Syst Sci Syst Eng333CONTROLs 2: Repuatons end soceral lave :。STATE THE PROBLEMPUTS }Elet systemnMagaetystem. curementsA_rqurtemertaConopL Rquremerts Venficaton and Tnaceabity Matrx (RVTM)I Requrements tunctona and prfomancel ]{ Valdaton cntenaAchtecural consrantsEnerprise nfasructue ;Figure 4 OPD for the 'State the problem' functionstakeholders' objectives, their verification andArchitecting the system is one of the systemsvalidation methods, and a registry of the historyengineer most important tasks, embracingfor each requirement.technical knowledge and also creative work. TheSummarizing, this function aims to identifyarchitecture establishes a framework for theall the relevant stakeholders and to understanddevelopment of the system that will satisfy thetheir needs well enough to support therequirements. If the system will only use COTSarchitecture design process. It is a crucialcomponents, the architecture definition relies onfunction for the development of a successfulchoosing those components but, if there will besystem that is, a system which meets the needsdesign and creation of components, architectingof its clients. These needs must be, sometimes,will be more creative and challenging.discovered and explained by the systemsThe most important activities of this functionengineer.consist of: defining goals， objectives andevaluation criteria for tradeoff studies; involving3.2 Investigate Alternativesdomain experts and all the relevant people toThis function has as main objectives toidentify and evaluate altermnative designs;explore altermative concepts for the solutionconducting trade off studies with updatedsystem and to design its baseline architectureinformation and with sensitivity analyses;(selection of the types of system elements, theirmaking decisions considering multicriteriacharacteristics, their arrangement， and theirtechniques; definingthearchitecture;interactions). The identification of altermnativespartit中国煤化工and allocatingclarifes the requirements thus reducing risk.themYHC NM H Gs; identifyingRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems334J Syst Sci Syst Enginterfaces within the system and with extermalcompliance with standards is essential tosystems; and defining an integration plan.guarantee existing and potential interoperability.It is important to keep in mind that theThe ConOps, the requirements, the RVTM,alternative designs can be explored in parallel orthearchitecturalconstraintsand the .sequentially, with successive revisions, andspecifications of interacting systems external toshould be evaluated through performance & costthe system-of-interest are the key inputs to thisfigures of merit (quantification of requirements).function. The OPD for the function InvestigateNone of the feasible altermatives is supposed to altermatives is depicted in Figure 5.optimize all the criteria so, there will beThe major outputs of this function includetradeoffs. Prototypes and simulation models canthe baseline architecture for the system, thehelp to assess preferred solutions.high-level description of their elements, theirThe interfaces between system elements andmain interface requirements, the plan totheir integration should take particular care ofintegrate them, and the RVTM updated withhuman aspects (Human System Integration). Therequirements assigned to major system elements.interoperability is another critical issue onarchitecting in a modern environment. With3.3 Model the Systemgrowing large and complex systems, it is vital toThis function is also commonly referred asensure the compatibility of system components'Design the system'. In fact, Blanchard &(which can be systems as well) to work as aFabrycky (2006) consider the State the problemwhole. Besides the current components, legacyand Investigate alternatives as 'Conceptualand future ones must be considered. TheDesign', the Model the system as 'PreliminaryCONTROLs r- : Agreements:; Propect posseses :i Reguablops and soow ;1INVESTIGATE ALTERNATIVESCanernaie desigsCongdutradeMake andDefinethedecsionsarchtecture|AAlocate systerEylucteConOpsaseline arcntecture designporponets! RequrementsUpdaled RVTMRVTM ISystems elements descnptonArchitecural constarntsInterface requremens and Systern megaon planInertacng systems secfiamons 1: ENSBERS :中国煤化工-Figure 5 0PD for the Investigate aYHCNMHGRamos et aL: Revisiting the SIMILAR Process to Engineer the Contemporary Systems」Syst Sci Syst Eng335System Design’ and the Integrate function asdevelopment of models. The main activities may'Detail Design and Development'. According tocomprise the functional decomposition of theBuede (2009), design“is the preliminary activitysystem, the selection of the appropriate model(s)that has the purpose of satisfying the needs offor the particular objectives and characteristicsthe stakeholders, begins in the mind of the leadof interest; the development of the model(s); theengineer but has to be transformed into modelsverification and validation of the model(s); theemploying visual formats in a highly skilledoperation of the model($); the analyses of result;manner for success to be achieved (..) there isthe refinement of the model(s); the completealways an element of artistry". For Wymorelow-level design of the system, and the selection(1993) design a system“is to develop a modelof COTS components. The selectionofon the basis of which a real system can be built,technology should be delayed until the rightdeveloped, or deployed that will satisfy all itschoice can be made that is, until there is a solidrequirements".understanding of the requirements and of theModel the system is a function employedarchitecture of the system. The OPD for thesince the early beginning of the“reason to do"function Model the system is depicted in Figureuntil the deployment of the system. The modelsare defined, extended, refined and validatedIn the high-level design developed during thethroughout the entire system's lifecycle. Theinvestigation of altermatives, the functionalitymodel is a simpler representation of theand performance of each component are defined.system-of-interest. This representation can beIn the detailed design, the architecture is refinedaccomplished through several kinds of modelsand the design specifications for hardware,likeprototypes,blueprints,FFBD,software and bioware components specify howobject-oriented diagrams, and simulations.they will be implemented in order to meet theThe models are cost-effective tools to createrequirements.data in the analysis domain and provide anThe major inputs are the ConOps, theapproximation of structure and/or behavior (ofbaseline architecture design and the RVTM,he system) which help to support bettercontrolled by settled agreements, the projectdecisions with less risk of failure in the finishedprocesses and the business regulations andsystem.The models can enhance thestandards. The enterprise environment can act asclarification of requirements, the identificationactivities' enabler as well as the selectedof bottlenecks, and the exposure of efforts'modeling tools.duplication. As obvious, the time and resourcesThe outputs of the function are verified,used to develop and to operate these modelsvalidated and documented models whichmust not exceed the value of the informationprovide a complete low-level description of theobtained through their use.system (they can be generally referred asThe major objective of this function is toModel-basedsystemdesigm).Integration,provide a comprehensive description of thever中国煤化工make also partsystem and of all of its components through theYHCNMHGIBSEreliesonRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems336JSyst Sci Syst EngMODEL THE SYSTEMDO Lunctonal ,SolodtheRefne theCUTPUTSmodelG)( VBVh( Perfom sensdvity )( Desugn the systemModel-based system desgn{ ConOps ISelect COTScompnenspIntegraton andV8V plans「Baseine archuecturedesgnRVTM ]; EHUABLERSMocdelng loFigure 6 OPD for the 'Model the system' functionusing well structured models that are suitable forverification and validation procedures to ensurehe given problem domain (Bahill and Bottacorrect boundaries, correct data flow, proper2008).interactions and fulfilleld requirements. Thisprocess is usually taken iteratively and bottom3.4 Integrateup. That is, the components at the lower level ofSystem integration means build the systemthe hierarchy are integrated and verified first.bringing things together so they work as a wholeThe process continues until the entire system isand provide emergent behavior (the essence ofintegrated and verified against all of itssystems thinking). This function is intimatelyrequirements. Like in a business environment,connected with the previous one since systemsall activities must be totally integrated under aengineering modeling implies holistic designcommon direction or plan that supports thewith interactions prominence. The developmentvision/mission and the goals of the enterprise.of software and hardware units,， and theThe majoractivitiesinclude theinterfaces are the core business of the functiondevelopment/purchase of software/hardwarewhich main purpose is to “realize theunits (based on detailed models); the design andsystem-ofinterest by progressively combiningmanagement of internal interfaces and interfacessystems elements in accordance with thewith_ extemal systems; the definition of anarchitectural design and the integration strategy"integ中国煤化工availbility of(INCOSE 2007a) and with correspondingsyste:MYHCNMHGofthesystemRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJ Syst Sci Syst Eng337(or build the system); the human systemsmanaged.integration; the verification of the system; theThe acquired COTS components, the writtenapplication of corrective actions in the event ofsoftware and the built hardware are nownon-conformance; and the demonstration ofworking as a coherent whole. The integrativeend-to-end operation. The OPD for the functionefforts require extensive communications anIntegrate is depicted in Figure 7.coordination between legacy systems ownersThe hierarchy of the system, provided by theandoperators, stakeholders, and systemdetailed models, offers a good knowledge of theimplementers.system's structure and supports the definition ofThe verification of the system intends toinerfacing subsystems and components. Theguarantee that the system“has been built right"subsystems should be defined along naturalwith all the requirements being fulfilled. Theboundaries to minimize the amount ofverification procedures like tests, analyses,information, physical items, and energy to beinspections, demonstrations, and certificationsexchanged between them. They should sendshould be selected according to the perceivedfinished products to other subsystems throughrisks, safety and criticality of the element underfunctional or physical interfaces.Interfaceanalysis.control documents should be developed and| Agreements 1CONROLSAProject processesINTEGRATEDefine na untegratonDevelop software/hardware untsDesign and manageinerfacesBuld the systemINPuTSDo Human Systems， CUTPUTSIntegratonensVerity the systemDemonstrate end-to end~Integrated andverifed systemf ConOpsApply corrective{ Updated RVTMactions厂Baseline archtectureResuits of verfcation and crrectivesiotecure |actons lakenRVTM! ENABLERS 1Enterprise infrastucture.......t Mode-based system designEnterprise plicies. processes and standardsCOTS componentsA Delopentts i1..........Venfication citenaIntegraton tols,s failtese. test equipment中国煤化工Figure 7 OPD for the 'ntegrMHCNMHGRamos et al: Revisiting the SIMILAR Process to Engineer the Contermporary Systems338J Syst Sci Syst EngThe Human Systems Integration (HSI)This transition stage also includes logisticfocuses on the system's human elementsupport equipment, operators' training and otherincludingpersonnel(owners, users,enabling systems, as well as basic acceptancecustomers, operators, maintainers, trainers...)ests to confirm that the system performs aswho interact with the system, providing a“totalintended in its deployment site(s), and to besystem”approach. The human centered concernsaccepted to go operational. The eventualof this process should be considered throughoutdetected anomalies and malfunctions should bethe system lifecycle, within and across allreported and corrected. Sometimes it issystem elements but, they are particularlynecessary to install the system in stages, whethercritical in the integrative process. HSI seeks todue to budget constraints, to risk diminishing, ortreat human elements as other system elementsto other projects' synchronization.such as software or hardware, being integrationThe transition to full operation can beessential to ensure adequate interfaces betweenparticularly complex when the system of interestman-machine. The people outside the systeminteroperates with several other systems, whenmay be affected by its operation so, it isthere is a replacement of an old familiar system,important to consider these interactions as well.when there are disruptions on client services, orAccordingtc(INCOSE2007a)hewhen there is a considerable amount of humanhuman-centered domains considered in HSI are:interaction. The design of effective trainingmanpower, personnel, training, human factorssystems is of paramount importance to warrantengineering, environment, safety, occupationaloperators with adequate knowledge andhealth, survivability, and habitability.capabilities to run the system properly.The main inputs for this function include theThe transition phase is usually followed byConOps, the architecture design, the RVTM, thethe system validation. As already mentioned, thedetailed models of the system (model-basedverification process ensures that“the system wassystem design), the acquired COTS componentsbuilt right” while the validation processand the verification criteria. The developmentguarantees that“it was built the right systerm".and integration tools can facilitate the integrativeThe objective is to confirm that the entire systemactivities. The key output of the function is anis working according to the stakeholders'integrated verified system able to be launched.requirements (ConOps) and to the validationThe RVTM should be updated and the results ofcriteria previously defined. This process canthe corrective actions resulting from integrationonly be accomplished when the system is in itsand verification procedures should be reported.operational environment and is being used bythe real users. To avoid unpleasant surprises it is3.5 Launch the Systemdesirable to perform in-processvalidationThe verified system is installed in itsthrough the corroboration of the differentoperational environment (if not developedproducts (like the ConOps, the design models)in-bouse) and the responsibility transferred ftomthat中国煤化工-interest.the development team to the client organization.CNMH Gn is operatedRamos et al: Revising the SIMILAR Process to Engineer the Contemporary SystemsJSyst Sci Syst Eng339producing the desired outputs (the system isan effective installation and operation.doing what it was designed to do in its ordinaryThe major outputs involve the installedsteady state). The OPD for the function Launchverified & validated system operating accordingthe system is depicted in Figure 8.to the users' needs, a list of eventual correctiveThe main inputs to launch the system includeactions detected by acceptance tests orthe integrated and verified system, anvalidation procedures and discussed with theinstallation plan, the prepared operationalsystem client, the final documentation of theenvironment involving the people, the facilities,system, training materials and the systemand the processes, the validation plan andmaintenance plan to allow a first-class long life.criteria, the consumables required to the normaloperation of the system, and the operational3.6 Assess Performanceprocedures to guide its deployment. The projectThis function intends to evaluate theprocesses like, for example, configurationperformance of the system through measurement.management, the agreements on supply“If you cannot measure it, you cannot control it;conditions, and the ConOps maintain controlif you cannot control it, you cannot improve it"over the system.(Bahill & Gissing 1998). The system should beBesides the infrastructure and the enterprisecontinuously monitored in order to provideintermal organization， the conditions of theoperational data, in order to be evaluatedoperational site provided by the system clientthrough defined metrics, and in order to beand the support systems like logistics,maintained, changed, corrected, upgraded, anddocumentation, and training schemes can enableimproved. Recording, documenting, and; CONTROLSConCps :...... .' LAUNCH THE SYSTEMCIntal the oyolemTrain the users_CTest lotasl sytemCImPUIS |Ccoepuance est( Apply corectre actlons /1V8V systemIntegrarede and verthed 1Valdateo the” system"Operate theacionsByslem .{ Iiallatlan planl Fnal doumetabon and traning matenalsenvronment-Mantenance plan; Enterpnse niastucturei Consumables I: Enerpnse plces, poceses and standardsHOperatonal proceduresEnabling srstems，中国煤化工-Figure 80PD for the 'Launch the'YHCNMHGRamos et al; Revisiring the SIMILAR Process t0o Engineer the Contemporany Systems340J Syst Sci Syst Eng: CONTROLS iOperabonalConOps:ASSESS PERFORMANCEMontor opeaiongCollet performance measuresP OUTPUTSmPertormosactons「Perormance measures/gevaions and aciongt Istalled V8V systemI Reporting of fluesdevabors and”1 recommencatons for actonl Mantenance plant Replaceable matenals; ENABLERS :; EHABLERS iEnterpnse nfastuture :Enterprse polce, processse and standardstenetprspeseess; Operabonal enmomment; Enabing eystems IFigure 9 OPD for the 'Assess perfomance functionreporting these issues are vital tasks to trackof technical performance measures related withchanges, control versions, and notice trends.the SE process. A metric is a measure ofThe system performance is assessed throughperformance compared to what it is expectedfigures-of-merit (typically used to quantify(target value) and is associated with the systemsystem requirements in the trade-off studies), .effectiveness. The performance measures andtechnical performance measures (normally usedmetrics for a given system are intimately relatedto monitor system performance during thewith its nature but they can include, for example,design, development and manufacturing), andproductivity, customer satisfaction, number ofmetrics (typically used to help manage adefects reported. The collection of data that willcompany's processes) (Bahill & Gissing 1998).not be used for any purpose should be avoided.A performance measure is a quantified valueThe main activities included in this functionof a given physical or functional attributeinvolve the monitoring of operations (design,relating to the execution of a process, function,development, and operation), the collection ofactivity or task. It can be related with quantitytechnical performance measures and defined(how much or how many), quality (how well),metrics, the establishment and execution oftimeliness (how responsive, how frequent), andmaintenance procedures, and the reporting ofreadiness (when, under which circumstances).measures, deviations and recommended actions.The number of requirements defined, theThe Assess performance function is normallynumber of SW modules completed, the numberappl” 中国煤化工stem lfecycleof acceptance tests passed are classical examplesinclt_.nd the activeTYHCNMHGRamos et aL: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJSyst Sci Syst Eng341system-of-interest. In this last case, the maindisposal with the intent to permanentlyinputs enclose the installed system, the definedterminating its use. In the moderm days, themaintenance procedures and eventuallydesign of the system takes into accountreplaceable materials required for systemenvironmental considerations and considerspreservation. The chosen monitoring systemsdisassembly,reusing,reprocessing,andand maintenance systems can facilitate therecycling procedures in order to contribute to;activities. The OPD for the function Assessbetter environment (Design for Environment).performance is depicted in Figure 9.Concepts such as Zero Footprint, ZeroThe major outputs of this function includeEmissions, and Cradle to Cradle cyclesthe technical performance measures and the(materials perpetually circulating in closed loops)metrics of the system as well as the reports 0re driving current trends toward corporatethese measures and detected deviations. Theresocial responsibility (INCOSE 2007a). The ISOshould be recommendations for subsequent14000 series definethe standards focorrective actions, upgrades, changes, or anyEnvironmental Management Systerms and Lifeother enhancement. This measurement allowsCycle Asssment. The OPD for the functioncontrol over the system, and the control allowsRe-evaluate is depicted in Figure 10.continuous improvement.The major inputs of this function calembrace the installed V&V system (or any of the3.7 Re-evaluateother SE process functions)， the assessedThe function Re-evaluate means feedback.performance measures/metrics and the disposalFeedback, one of the most importantrequirements. The agreements with stakeholders,engineering tools, means observing outputs andtheinternal disposal procedures, theusing this information to modify the systems, itsindustry/service standards for disposal, and theinputs, and the process. The re- evaluation shouldGovermment and regulatory agencies control thebe a continual process with many parallel loops,disposal activities. The major outputs of thisused as needed (Bahill & Gissing 1998).function include the reports of carriedContinuous re-evaluation ensures controlimprovements, a possible disposed system, andover the system and quality improvement.some archival documentation registering theImplementing changes, upgrading versions,final system configuration and also the“lessonscorrecting procedures, and improving methodslearmed".are typical activities derived from re-evaluation.In conclusion, the SIMILAR process foEvery time the system is altered, by means ofdoing SE can be applied vertically andsoftware upgrades, hardware replacements, jobhorizontally, is dynamic, repetitive, recursiveenrichment, there should be a registry in order towith multiple feedback loops, iterative, and withcontrol the system configuration and to maintainmany things done in parallel (Bahill & Gissingall the system data updated.1998). The development of models during theFrom a system lifecycle perspective, theState中国煤化工ate alemativessystem re-evaluation can lead to its (or elements)funct:MYHC N M H Grelopment ofRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems342JSyst Sci Syst Eng------1! CONTROLS5 Governmemit and rgugafoiyiRE EVALUATESaradstodosposad;Use fedbac( Improve the ystem )DocumentOUTPUTSI NUTSControl ystem coniguratbonJRepont of mprovementselementsvenare system ,t Isatlled V&V systemDisposed systemPerormance measuresuncluding essons Leamed jf Dsposal requrements: ENABLERS :..........Figure 10 OPD for the "Re evaluate' functionModeling and Integration functions, and thethere is a lack of unified principles, models, anditerative andconcurrent application ofconsistent terminology and definitions, and thereAssessment and Re-evaluation at each of theis a perception that SE is excessivelyother functions are clearly examples of the“notcumbersome and not applicable to small projects.sequential”nature of this process. Despite itsThe following paragraphs describe some of theuniversal nature it must be framed in the contextmajor topics that are believed to drive theof the SE process international standards such asdevelopment of modem SE in the next years.the reference norm ISO/IEC 15288. The authorsThe description includes a particular mention tohope that this explanation can contribute to thisthe MBSE approach that, from the authors' pointintegration and to a more oriented application ofof view, will be a prominent theme.the ISO processes through the “glued"The application domains of SE are definitelySIMILAR process model.evolving to a broader number of sectors goingbeyond the traditional Aerospace & Defense4. Some Emerging Trendsdomain. The Energy, the Transportation, theThe emergence of a widespread and effectiveSustainable Development, and the HealthcareSystems Engineering practice is becoming a fact,sectors are already target areas for SEas well as the realization that SE is critical toapplications.The enterprise collaborativesuccessfully design, develop and sustain the 21stenvironments of thesedomains, wherecentury complex systems. The field is broad,中国煤化Iulti-disciplinaryinterdisciplinary, and dynamic. Nevertheless, tean:YHCNMHGareandwillbeRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJ Syst Sci Syst Eng343the dominant working environments.work-centered design (Miltello et al. 2010). TheThe complexity of these modern systems isUbiquitousComputing, Human Computerdefinite evidence. There are several researchInteraction, User Centered Design, and Usabilitylines working on Complex Systems EngineeringEngineering are also modem topics in this field(CxSE)，on the chaos theory, and on thethat have matured over the last three decades.complexity theory as the foundation for the newThey focus on effective user interfaces and aimsystems engineering (Honour 2008, Sheard &“to develop a system where human and machineMostashari 2009). The Systems of Systemssynergistically and interactively cooperate toEngineering (SoSE) is another topic ofconduct the mission" (Hardman et al. 2009).significant interest with particular dedication toLean Systems Engineering joins the Leanhighly network centric systems where a complexThinking paradigm to Systems Engineering withset of people, devices, information and servicesthe intention to deliver lifecycle value to(nodes) are interconnected by a communicationsstakeholders of complex systems with minimumnetwork to achieve optimal benefit of resourceswaste of resources, delays, cost overruns, andand better synchronization of events and theirfrustrations Murman 2008, Oppenheim 2009).consequences (Chen & Clothier 2003, JamshidiThe value can be seen as a tradeoff between2008, Lane & Bochm 2008). The interfacestheir contributions to the system and the worth,within the system-of-interest and with the otherutility, benefit, or reward they find in it. Ainteracting systems are significantly and thecollection of more than 190 bolistic practicesissue of effective integration is critical.and recommendations is being collected andThe synchronization, privacy and securitydisseminated by the INCOSE Lean Systemsissues of these new large heterogeneous systemsEngineering Working Group, under thewill be major challenges, as well as theirdesignation of Lean Enablers for Systemsresilience to failure (Kalawsky 2009).Engineering. This product is organized under theThe human role in large, complex ansix well known lean principles: Value, ValueinterdisciplinarysystemsisparticularlyStream, Flow, Pull, Perfection, and People. Theimportant not only as system components butLean Advancement Initiative at MIT is anotheralso as integrative and decision making elements.research consortium working on these matters.In this sense, Human Systems Integration is anThe MBSE approach is expected to play, inessential enabler to systems engineering practicethe next decade, an increasing role in the(Mueller 2008). The Cognitive Systemspractice of systems engineering. According toEngineering (CSE) is one of the key researchINCOSE (2007b)， the future of Systemstopics in this field. CSE is “an approach to theEngineering will be model-based, embracingdesign of technology, training, and processeshigh-fidelity static and dynamic models aintendedtomanagecomplexity indifferent levels of abstraction. As a recent trend,socio-technical systems” and includes domainswithin the, SF field. it dnes nnt have, by this time,like cognitive work analysis, decision centered中国煤化工ece of theory.design, situation awareness oriented design, and NevTYHCNMHG1ideabehindallRamos et al: Revisiting the SIMILAR Process to Engineer the Contemporary Systems344J Syst Sci Syst Eogthe on-going published research efforts: theSysML, the ISO 10303: AP233, the XMI, thecritical importance of modeling in engineeringHLA，and the MDA are impelling thecomplex socio-technical systems.proliferation of the MBSE paradigm.Modeling in Systems Engineering meansThe future of MBSE will be facilitated byprimarily to create a shared vision among thethecontinuouslyevolvinginformationsystem's stakeholders, to specify, describe,technologies (computing power, storage andcommunicate，and test that shared vision, toanalysis capacities, distributed capabilities,estimate or predict some quantitative measure ofvirtual networking, etc.) as well as by the finethe system, and to select design options (Buede tuned profile of the systems engineers (the2009, Van Daalen et al. 2009). As Buede (2009) proliferation of SE courses at the variousalso states “In fact, models are so pervasive ingraduation levels and the adaptive profile innatethe engineering of systems that engineers mustto the new generations will contribute to thealways remind themselves not to confuse realitySystems Engineer of the future).with the models of reality that are being created,tested, and used".5. On-going Work and ConclusionThe main principle underlying the MBSEThe work presented in this paper results fromapproach relies on the creation of a coherentthe need to develop a contemporary large,model of the system being developed. Thiscomplex，socio-technical SoS， the IUTEOmodel-centric approach is expected to replace, insystem (Ramos et al. 2008), and the necessity tothe next years, the traditional document-centricestablish an updated framework for itsapproach that is based on documents written indevelopment process. The system is naturallytext. The SE process is accomplished withwell suited to be used by the relatively immatureincreasing detailed models that are all part of theSE field asempirical research to drivesystem model. The major advantages of thisknowledge evolution and theory buildingapproach include enhanced communications(Valerdi & Davidz 2009). The authors alsobetween the stakeholders and team members asbelieve that it is a representative“super system”well as a true shared understanding of theof the modern days, being a considerabledomain, improved design precision and integritychallenge for the contemporary SE.withoutdisconnectionsamongThe traffic at urban centers is a majorrepresentations of data, better informationconcermn for local authorities since it istraceability, enhanced reuse of artifacts, andresponsible for several environmental damagesreduced development risk. As Friedenthal et al.that affect considerably the city users' quality of(2008) state, “the emphasis is placed onlife. The existing urban transport system must beevolving and refining the model using modelreengineered and managed in order to gebased methods and tools" so, the prominence ofefficient traffic solutions that mitigate thecontrolling documents is now replaced byenvironmental side effects reflected on aircontrolling the model of the system. ThequalitMH中国煤化工tion, acidentsstandards evolution in the field, including theand saC N M H Gcomprehensive,Ramos et al: Revisiting the SIMILAR Process to Engineer the Contemporary SystemsJSyst Sci Syst Eng345integrated, and action-oriented system forthey work together (the dependencies) toIntelligent Urban Traffic & Environmentachieve the system's overall principle (theOperations (IUTEO) is of critical importance towhole).address the needs of local governors and toThe proposed SE development approach issupport the complex challenge of sustainablebased on the formalized application of theurban mobility. The system also strengths threvisited SIMILAR process, as described irpublic active participation in the developmentTable 1. This mapping is a result of the authors'and decision processes. The backdrop of thevision of the system and constitutes the guidingsystem are the Intelligent Transportationframework that is driving the system'sSystems (ITS) which encompass a broad rangedevelopment.of wireless communications-based information,As previously described, in Section 3, thecontrol and electronics technologies embeddedfunctions of the revisited SIMILAR process arein the system's infrastructure and vehicles tothe same but they are now analyzed at the lightrelieve congestion, improve safety and enhanceof the modern SE process standards. The Modelproductivity. The system's general structure isthe System function will be emphasizeddepicted in Figure 11. Each of the depictedilustrating the fundamental role of the modernmodules (the parts) serves a specific purpose butMBSE approach. In fact, the Model function isDataDatabase, ModellingApplications forReal SystemAcquisitionand Analysis Platform Municipalities本昌Cmommricaions Sesing & Surllance, Ifomaton & ControlFigure 11 IUTEO system: general stuctureTable 1 The IUTEO system mapped to the SIMILAR processThe SIMILAR processThe IUTEO systemState the problemAssess the need for the system and define the stakeholders' requirementsInvestigate alternativesDesign the architecture of the systemModel the systemModel-Based Systems EngineeringIntegrateIntegrate the different subsystems and interfacesLaunch the systemInstall, operate and manage the IUTEO at the municipalitiesAssess performanceTest, evalu中国煤化工Rc-evaluateMaintain, upgrade,TYHCNMH2TEORamos et al: Revisiting the SIMILAR Process 1o Engineer the Contemporary Systems346J Syst Sci Syst Engtraversal to the entire process being used tAcknowledgmentsdefinetheusers’needs, thesystemThe authors would like to express theirfunctionalities, the system architecture, thegratitude to the valuable comments of theinterfaces, etc.referees that have improved significantly theA successful MBSE context consists of aquality of the paper.Systems Engineering process (in this case, therevisited SIMILAR process), a set of modelingReferencestools that can be, for example, languages (in this[1] Arlow, J. & Neustadt, I. (2005). UML 2 andcase, the SysML and the OPDs/OPL), sofwarehe Unified Process: Practical Objectenvironments (in this case, Artisan Studio,Oriented Analysis and Design, 2nd Edition.OPCAT,Arena), and/or interoperabilityPearson Education, Inc, Massachusettsmechanisms (e.g., XMI， AP233)， and a[2] Amold, S. (2007). Where is standardizationmodeling methodology. By this time, the IUTEOguiding us?. INSIGHT-INCOSE Joumnal, 10system is at the Integrate stage. A following(2): 41-43paper will describe the modeling activities and[3] Bahill, A. & Botta, R. (2008). Fundamentalthe major findings in this traffic engineeringprinciplesof gooddesign.field.Engineering Management Joumal, 20 (4):It was the authors' aim to describe the main9-17aspects of moderm Systems Engineering, the[4] Bahil, A. & Briggs, C. (2001). The systemsrelevant standards in this field, as well as theengineering started in the middle process: aforemost emerging trends.consensus of systems engineers and projectIt was also intended to rediscover themanagers. Systems Engineering, 4 (2):SIMILAR process, a universal SE process, in156-167order to align/integrate it with the ISO[5] Bahill, A. & Gissing, B. (1998).intermational standard, so it can be used in theRe-evaluating systems engineering conceptspresent- day context. The ISO standard includesusing systems thinking. IEEE Transactionsa series of SE processes that, from the authors')n Systems, Man and Cybermetics - Part C:point of view, require some further integration.Applications and Reviews, 28 (4): 516-527The authors' hope that this work can contribute[6] Bahill, A., Brown, P.. Buede, D. & Martin, J.to this integration and to a more oriented(2002). 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System of systemsengineering design process. Systemsengineering - new challenges for the 21stEngineering, 13 (3): 261-273century. IEEE Aerospace and Electronics[39]Mueller, M. (2008). Human systemsSystems Magazine, 23 (5): 4-19integrationwhat's it all about?.[30]Kalawsky, R. (2009). Grand challenges forINSIGHT-INCOSE Jourmal, 11 (2): 7-10systems engineering research. In: Kalawsky, [40]Murman, E. (2008). Lean enablers forO'Brien, Goonetilleke (eds.), 7 Annualsystems engineering. Paper presented at theConferenceonSystems EngineeringLeanAdvancementInitiative(LAI)Research (CSER 2009)， Loughborough,Conference, MIT, Boston, April 22-24,April 20-23， 2009， Research School of2008[41]Oppenheim, B. (2009). Lean enablers for[31]Kim, C.H., Weston, R., Hodgson, A. & Lee,systems engineering. INSIGHTINCOSEK.H. (2003). The complementary use ofJoumal, 12 (1): 35-36IDEF and UML modelling approaches.[42]Ramo，S. (2004). Systems EngineeringComputers in Industry, 50: 35-56Manual. Federal Aviation Agency (FAA)[32]Kruchten, P. (1995). The 4+1 view model of [43 ]Ramos, A., Ferreira, J. & Barcelo, J. (2008).architecture. IEEE Software, 12 (6): 42-50A framework for intelligent urban[33]Lane, J. & Boehm, B. (2008). System ofenvironmental traffic management: the datasystems lead system integrators; where doacquisition module's case. In: Proceedingsthey spend their time and what makes themof the 15th World Congress on Intelligentmore or less efficient? Systems Engineering,Transport Systems, New York, November11 (1): 81-9116-20, 2008[34]Maier, M. & Recthin, E. (2002). The Art of [44]Rhodes, D. (2008). Addressing SystemsSystems Architecting, 2nd Edition. CRCEngineeringChallengesThroughPress, FloridaCollaborative Research. SEARI-Systems[35]Maier, M. (2006). System and softwareResearcharchitecturereconciliation.SystemsInitiative. Massachusetts InstitutefEngineering, 9 (2): 146-159Technology[36]Martin, J. (2000). Processes for engineering[45]Richards, M., Shah, N, Hastings, D. &a system: an overview of the ANSI/EIA 632Rhodes, D. (2007). Managing complexitystandard and its heritage. Systems中国煤化Inse architetureEnginering, 3(1): 1-26YHC NM H Gof a dynamicRamos, Ferreira and Barcel6: Revisining the SIMILAR Process to Engineer the Contemporary SystemsJSyst Sci Syst Eng349system architecture model. Working PaperAna Luisa Ramos received the M.Sc. degree inESD-WP-2007/09，Engineering Systermscomputers engineering from the University ofDivision, MITCoimbra, Portugal, in 2002 and is currently[46]Ross, D. (1977). Structured analysis (SA): a taking the Ph.D. in Industrial Management in thelanguage for communicating ideas. IEEEUniversity of Aveiro, Portugal. She is anTransactions on Software Engineering, 3 (1):Assistant Lecturer of Management and16-34Industrial Engineering (MIE) at the University[47]Sheard, S. & Mostashari, A. (2009).of Aveiro, where she was the Vice-Director ofPrinciples of complex systems for systemsthe MIE undergraduate program and theengineering. Systems Engineering, 12 (4):Coordinator of the Socrates/Erasmus Program.295-311She is author and co-author of several papers[48]Sheard, s. (1996). Twelve systemspublished in internationaljournals ancengineering roles. In: Proceedings of the 6thconference proceedings. Her research workAnnual International Symposium of thefocuses on modeling and simulation, andINCOSE, Bostonmodel-based systems engineering applied to the[49]Sommerville,(2007).Softwareindustrial and transportation sectors. She isEngineering, 8”Edition. Pearson Educationmember of the Intermational Council on SystemsLimited, LondonEngineering (INCOSE) and of the Portuguese[50]Tien, J. & Berg, D. (2003). A case forSociety for Operational Research (APDIO). Sheservice systems engineering. Joumal ofhas received the INCOSE Foundation/StevensSystems Science and Systems Engineering,Institute Doctoral Award for promising research12 (1): 13-38in Systems Engineering and Integration, in 2009.[51]Valerdi, R. & Davidz, H. (2009). Empiricalresearch in systems engineering: challengesJose Vasconcelos Ferreira received the M.Sc.and opportunities of a new frontier. Systemsdegree in operational research and systemsEngineering, 12 (2): 169-181engineering from the Technical University of[52]Van Daalen, C, Thissen, W. & Verbraeck,Lisboa, Portugal, in 1989 and the Ph.D. degreeA. (2009). Methods for the modeling andn engineering sciences from the University ofanalysis of alternatives. In: Sage, A., Rouse,Porto, Portugal, in 2005. He is an AssistantV. (eds.), HandbookofSystemsProfessor of Management and IndustrialEngineeringandManagement,pp.Engineering at the University of Aveiro where1037-1076. Wiley Interscience, New Yorkhe has been supervising several MsC and PhD[53]Wymore, A. (1993). Model Based Systemsresearch works. He is author and co-author ofEngineering. CRC Press, Floridaseveral papers published in book chapters,[54]Zachman，J. (1987). A framework forinternationaljoumalsconferenceinformation systems architecture. IBMproceedings. His main research interests includeSystems Joumal, 26 (3): 276-292the中国煤化工mass transitcompYHC N MH G for logistics,Ramos et al: Reisiting the SIMILAR Process to Engineer the Contemporary Systems350J Syst Sci Syst Engand multivariate data analysis. He is an activeInnovation in Transport at UPC. He is authorresearch member with more than twenty years ofand co-author of several papers published inexperience collaborating with the main urbanbook chapters, internationaljoumals andmass transit companies in Portugal. He works inconference proceedings. He is specialized inpartnership with a spin-off company dedicatedoptimization and simulation techniques foto Transportation Planning and Optimization.transportation-related problems. He has beencoordinator and partmer of innumerous projectsJaume Barcel6 received the Ph.D. degree inof the R&D Programs of the European Union.physical sciences from the AutonomousHe was the scientific director of TSS-TrafficUniversity of Barcelona, Spain, in 1974. He is aSimulation Systems, the spin-off company ofFull Professor of Operations Research at theUPC that commercializes the microscopic trafficTechnical University of Catalonia, in Barcelona,simulator Aimsun. He is associated editor ofand he is, since 2007, the Scientific Director ofseveral international publications and received,the Area of Information and Communicationin 2001, an Honour Mention of the city ofTechnologies and Mobility at the Center forBarcelona for technological innovation.中国煤化工MYHCNMHG