Grouping of Systems - SEBOK (14)

This article forms part of the Systems Fundamentals Knowledge Area (KA). It expands on groups of system classification introduced in Types of Systems. Systems can be grouped together to create more complex systems. In some cases, considering systems as system elements in a system hierarchy is sufficient. However, there are cases where the groupings of system produce an entity that must be treated differently from a single integrated system. This article explores the different descriptions of how and why system groupings might be considered.

System of Systems

The term “ system of systems” (SoS) is commonly used, but there is no widespread agreement on its exact meaning, or on how it can be distinguished from a conventional system. An extensive history of SoS is provided in “System-of-Systems Engineering Management: A Review of Modern History and a Path Forward” (Gorod & Boardman 2008). This paper provides a historical perspective for systems engineering from Brill (1998). The authors then provide a chronological history for SoS engineering from 1990 to 2008. Their history provides an extensive set of references to all of the significant papers and textbooks on SoS. Gorod and Boardman cite Maier as one of the most influential contributors to the study of SoS.

Maier provides this definition:

A system-of-systems is an assemblage of components which individually may be regarded as systems, and which possess two additional properties:

1. Operational Independence of the Components: If the system-of-systems is disassembled into its component systems, the component systems must be able to usefully operate independently. That is, the components fulfill customer-operator purposes on their own.

2. Managerial Independence of the Components: The component systems not only can operate independently, they do operate independently. The component systems are separately acquired and integrated but maintain a continuing operational existence independent of the system-of-systems. (Maier 1998, 271)

Four kinds of SoS have been defined (Maier 1998; Dahmann and Baldwin 2008; DUS(AT) 2008; Dahmann, Lane, and Rebovich 2008):

1. Virtual. Virtual SoS lack a central management authority and a centrally agreed upon purpose for the system-of-systems. Large-scale behavior emerges—and may be desirable—but this type of SoS must rely upon relatively invisible mechanisms to maintain it.

2. Collaborative. In collaborative SoS the component systems interact more or less voluntarily to fulfill agreed upon central purposes. The Internet is a collaborative system. The Internet Engineering Task Force works out standards but has no power to enforce them. The central players collectively decide how to provide or deny service, thereby providing some means of enforcing and maintaining standards.

3. Acknowledged. Acknowledged SoS have recognized objectives, a designated manager, and resources for the SoS; however, the constituent systems retain their independent ownership, objectives, funding, and development and sustainment approaches. Changes in the systems are based on collaboration between the SoS and the system.

4. Directed. Directed SoS are those in which the integrated system-of-systems is built and managed to fulfill specific purposes. It is centrally managed during long-term operation to continue to fulfill those purposes, as well as any new ones the system owners might wish to address. The component systems maintain an ability to operate independently, but their normal operational mode is subordinated to the central managed purpose (DUS(AT) 2008, 4-5; and, Dahmann, Lane, and Rebovich 2008, 4; in reference to (Maier 1998; Dahmann and Baldwin 2008)).

The terms emergence (glossary) and emergent behavior are increasingly being used in SoS contexts, fueled, in part, by the movement to apply systems science and complexity theory to problems of large-scale, heterogeneous information technology based systems. In this context, a working definition of emergent behavior of a system is behavior which is unexpected or cannot be predicted by knowledge of the system’s constituent parts. One of the leading authors in the area of SoS is Mo Jamshidi, who is the editor of a leading textbook (Jamshidi 2009) and articles such as “System of Systems Engineering – New Challenges for the 21st Century” (Jamshidi 2008). This article provides numerous references to papers that have examined the definition of SoS. The author selects six of the many potential definitions. His lead definition is Systems of systems exist when there is a presence of a majority of the following five characteristics: operational and managerial independence; geographic distribution; emergent behavior; and evolutionary development. (Jamshidi 2008, 5; adapted from Sage and Cuppan 2001, 326)

Families of Systems

The Defense Acquisition University (DAU 2010, 4.1.4. System of Systems (SoS) Engineering) defines families of systems as:

A grouping of systems having some common characteristic(s). For example, each system in a family of systems may belong to a domain or product line (e.g., a family of missiles, aircraft, or situation awareness systems). In general, a family of systems is not considered to be a system per se because it does not necessarily create capability beyond the additive sum of the individual capabilities of its member systems. A family of systems lacks the synergy of a SoS. The family of systems does not acquire qualitatively new properties as a result of the grouping. In fact, the member systems may not be connected into a whole. (DAU 2010)

Valor de la planificación de un ERP (37)

¿Por qué podemos estar seguros que una solución ERP genera un valor agregado para la organización?. Si consideramos al sistema ERP como un sistema de clase mundial que involucra las mejores prácticas con estándares de excelencia, y que la organización que adopte esta filosofía, podrá como resultado obtener una reducción significativa de costos, un aumento de la productividad, planificar y realizar la automatización de sus procesos, así como la integración completa del negocio e incorporar las mejores prácticas mundiales de la industria. Así, estos beneficios serán considerados vitales para la organización.

En el Perú, aproximadamente, la mitad de las empresas que pueden acceder a esta tecnología ya lo han hecho; entonces, ¿por qué las empresas restantes pierden la oportunidad de lograr ventajas competitivas que las diferencien de sus competidores? Una de las principales causas por la cual muchas empresas no han optado todavía por este tipo de tecnologías es por la coyuntura que se plantea a llevar a cabo estos sistemas, teniendo en cuenta los gastos que conlleva en términos de dinero, esfuerzo y tiempo. Para no poner en riesgo una gran inversión como ésta, es importante un cambio de mentalidad en la empresa.

Todos hemos escuchado, directa o indirectamente, algo sobre situaciones conflictivas durante la implantación de soluciones ERP. Existen experiencias, locales e internacionales, que han ocasionado grandes pérdidas a las empresas; otras que han burocratizado los procesos, de tal manera, que por ejemplo, han triplicado los tiempos de ejecución en la emisión de una orden de compra; y por supuesto, también se sabe de proyectos mal liderados, que han cuadruplicado el original en esfuerzos, presupuestos y tiempos.

La elección de un sistema ERP debe hacerse luego de un análisis exhaustivo y detallado de la situación actual de la empresa, la cual deberá estar alineada a la estrategia de la organización, revisando la disponibilidad de recursos con experiencia, así como aspectos vinculados con liderazgo y conocimiento de la organización, madurez y credibilidad en los procesos existentes y el grado de confiabilidad de los datos.

Entonces, implantar un ERP permite a cualquier organización una respuesta adecuada y que estaría a la medida de sus necesidades. Consecuentemente, una solución que permitirá una integración total entre sus diferentes módulos y el intercambio de datos entre ellos, con el fin de gestionar adecuadamente cada una de las áreas de la empresa. Debemos reconocer que, aunque las soluciones que tiene cada empresa implantada para la gestión de cada una de las áreas de su negocio funcionen muy bien y sus posibilidades de crecimiento sean bastante aceptables, los entornos y su intercomunicación son muy complicados.

Una premisa indispensable en toda implantación de sistemas ERP, es que la alta gerencia de la empresa debe brindar los requerimientos, medios y recursos necesarios al equipo de trabajo, para evitar las clásicas respuestas: «No hay tiempo» o «No hay soporte » por parte de la organización y el desfase entre lo que se desea del producto y lo que realmente se obtiene del mismo.

Type of Systems - SEBOK (13)

This article forms part of the Systems Fundamentals Knowledge Area (KA). It provides various perspectives on system classifications and types of systems, expanded from the definitions presented in What is a System?.

The modern world has numerous kinds of systems that influence daily life. Some examples include transport systems; solar systems; telephone systems; the Dewey Decimal System; weapons systems; ecological systems; space systems; etc. Indeed, it seems there is almost no end to the use of the word “system” in today’s society. This article considers the different classification systems which some Systems Science (glossary) authors have proposed in an attempt to extract some general principles from these multiple occurrences. These classification schemes look at either the kinds of elements from which the system is composed or its reason for existing. The idea of an engineered system (glossary) is expanded. Four specific types of engineered system context are generally recognized in systems engineering: product system, service system, enterprise system and system of systems capability.

System Classification

A taxonomy is "a classification into ordered categories" (Dictionary.com 2011). Taxonomies are useful ways of organizing large numbers of individual items so their similarities and differences are apparent. No single standard classification system exists, though several attempts have been made to produce an useful classification taxonomy. Bertalanffy (1968) divided systems into nine types, including control mechanisms, socio-cultural systems, open systems, and static structures. Miller (Miller 1986) offered cells, organization, and society among his eight nested hierarchical living systems levels, with twenty critical subsystems at each level. Peter Checkland (Checkland 1999) divides systems into five classes: natural systems, designed physical systems, designed abstract systems, human activity systems and transcendental systems. Checkland refers to these five systems as comprising a “systems map of the universe”.

Systems of Systems

Systems can be grouped together to create more complex systems. In some cases it is sufficient to consider these systems as systems elements in a higher level system, as part of a system hierarchy. However, there are cases where the groupings of system produce an entity that must be treated differently from an integrated system. The most common groupings of systems that have characteristics beyond a single integrated system are Systems of Systems (SoS) and Federations of Systems (FoS). Maier examined the meaning of System of Systems in detail and used a characterization approach which emphasizes the independent nature of the system element, rather than “the commonly cited characteristics of systems-of-systems (complexity of the component systems and geographic distribution) which are not the appropriate taxonomic classifiers” (Maier 1998, 268). Wherever independent systems are combined into groups the interaction between the systems adds a further complexity; specifically, by constraining how the resulting system can be changed or controlled. This dimension of complexity affects the management and control aspects of the systems approach.

Engineered Systems Classifications

The classification approaches discussed above have either been applied to all possible types of systems or have looked at how man-made systems differ from natural systems. A product or service is developed and supported by an individual, team, or enterprise. The nature of engineered systems has changed dramatically over the past several decades from systems dominated by hardware (mechanical and electrical) to systems dominated by software. In addition, systems that provide services, without delivering hardware or software, have become common as the need to obtain and use information has become greater. Recently, organizations have become sufficiently complex that the techniques that were demonstrated to work on hardware and software have been applied to the engineering of enterprises. Three specific types of engineered system context are generally recognized in systems engineering: product system, service system and enterprise system.

Products and Product Systems

The word product (glossary) is defined as "a thing produced by labor or effort; or anything produced" (Oxford English Dictionary). In a commercial sense a product is anything which is acquired, owned and used by an enterprise (hardware, software, information, personnel, an agreement or contract to provide something, etc.). Product systems (glossary) are systems in which products are developed and delivered to the Acquirer (glossary) for the use of internal or external user. For product systems, the ability to provide the necessary capability (glossary) must be defined in the specifications for the hardware and software or the integrated system that will be provided to the acquiring enterprise (glossary).

Services and Service Systems

A service (glossary) can be simply defined as an act of help or assistance, or as any outcome required by one or more users which can be defined in terms of outcomes and quality of service without detail to how it is provided (e.g., transport, communications, protection, data processing, etc.) Services are processes, performances, or experiences that one person or organization does for the benefit of another, such as custom tailoring a suit; cooking a dinner to order; driving a limousine; mounting a legal defense; setting a broken bone; teaching a class; or running a business’s information technology infrastructure and applications. A service system (glossary) is one that provides outcomes for a user without necessarily delivering hardware or software products to the service supplier. The hardware and software systems may be owned by a third party who is not responsible for the service. The use of service systems reduces or eliminates the need for acquirers to obtain capital equipment and software in order to obtain the capabilities needed to satisfy users.

Enterprises and Enterprise Systems

An enterprise (glossary) is one or more organizations or individuals sharing a definite mission, goals, and objectives to offer an output such as a product or service. An enterprise system (glossary) consists of a purposeful combination (network) of interdependent resources (e.g., people; processes; organizations; supporting technologies; and funding) that interact with 1) each other (e.g., to coordinate functions; share information; allocate funding; create workflows; and make decisions), and 2) their environment(s), to achieve business and operational goals through a complex web of interactions distributed across geography and time (Rebovich and White 2011, 4, 10, 34-35).

According to Maier’s definition, an enterprise would not necessarily be called a system of systems (SoS) (glossary) since the systems within the enterprise do not usually meet the criteria of operational and managerial independence. In fact, the whole purpose of an enterprise is to explicitly establish operational dependence between systems that the enterprise owns and/or operates in order to maximize the efficiency and effectiveness of the enterprise as a whole. Therefore, it is more proper to treat an enterprise system and an SoS as different types of things, with different properties and characteristics (DeRosa 2005). Enterprise systems are unique, compared to product and service systems, in that they are constantly evolving; they rarely have detailed configuration controlled requirements; they typically have the goal of providing shareholder value and customer satisfaction, which are constantly changing and are difficult to verify; and they exist in a context (or environment) that is ill-defined and constantly changing.

System of Systems Capability

The term System of Systems Capability is used here to describe an engineering context in which a number of enterprise, service and product systems are brought together dynamically to provide a capability which is beyond the scope of any individual enterprise. Understanding the need for system of systems capability is a way of setting a broader problem context for the engineering of other systems. Both product and service systems may be engineered to both satisfy immediate stakeholder needs and to have the potential to be used for the composition of SoS capabilities. Engineering at the Enterprise level can include an Enterprise Capability Management activity, in which possible SoS problems are explored and used to identify gaps in the enterprise's current product and service portfolio.