Model Management for Continuously Evolving Systems

نویسنده

  • Steve Easterbrook
چکیده

Software development today takes place in the context of a complex system-of-systems that includes a broad technological infrastructure along with a wide set of human activities. The technological systems and the human activity systems have a symbiotic relationship each shapes the other in complex ways, such that neither can be understood in isolation. A recent report from the SEI on Ultra-Large Scale (ULS) Systems accurately characterized the nature of these systems-ofsystems: they have no centralized control; experience normal failures and continual evolution of heterogeneous elements; and their requirements are inherently conflicting, diverse and often unknowable. For design purposes, the boundary between people and software disappears design is as much about shaping the human activities as it is about constructing the software. Although the SEI report focussed on the extreme scale, it is clear that most of these challenges now apply to most software development the complexity arises from the many different contexts in which any software component will be deployed. The engineering approaches we use today for software development only work when we take a very narrow view of the requirements, as well-defined sets of features and interfaces, which can be fully specified. This approach helps us to build components that conform (in a narrow sense) to their specifications. But we cannot tell in advance whether they will be any use in any of the many different systems-ofsystems in which they may be deployed. Our engineering techniques rapidly break down when we attempt to scale up our design ambitions. The result is a growing gap between expectations and practice in the software industry. We can build very reliable software at the small scale, for tightly constrained problems. But we cannot build reliable software for complex socio-technical domains. Our designs are brittle they fail in unexpected ways when the context in which they operate changes. To make progress on these challenges we need to abandon the idea that we can write complete, consistent requirements specifications. Instead, we need to capture the multiple, conflicting requirements for each software component that arise from its different contexts of use. We need to be able to express our partial understandings of the broader systems-of-systems in which our components will be deployed. And we need to be able to reason about the properties, and end-to-end behaviours of these systems, without resolving all the unknowns and inconsistencies in our models. In particular, we need techniques for managing large, evolving collections of fragmentary requirements models, and techniques to reason about the properties of these models and their interactions, even in the presence of inconsistency and incompleteness.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Potentials of Evolving Linear Models in Tracking Control Design for Nonlinear Variable Structure Systems

Evolving models have found applications in many real world systems. In this paper, potentials of the Evolving Linear Models (ELMs) in tracking control design for nonlinear variable structure systems are introduced. At first, an ELM is introduced as a dynamic single input, single output (SISO) linear model whose parameters as well as dynamic orders of input and output signals can change through ...

متن کامل

Non-physician Clinicians – A Gain for Physicians’ Working in Sub-Saharan Africa; Comment on “Non-physician Clinicians in Sub-Saharan Africa and the Evolving Role of Physicians”

The changing demands on the health sectors in low- and middle-income countries especially sub-Saharan African countries continue to challenge efforts to address critical shortages of the health workforce. Addressing these challenges have led to the evolution of “non-physician clinicians” (NPCs), that assume some physician roles and thus mitigate the continuing shortage of doctors in these count...

متن کامل

A Network Based Theory of Health Systems and Cycles of Well-being

There are two dominant approaches to describe and understand the anatomy of complete health and well-being systems internationally. Yet, neither approach has been able to either predict or explain occasional but dramatic crises in health and well-being systems around the world and in developed emerging market or developing country contexts. As the impacts of such events can be measured not simp...

متن کامل

Is the Role of Physicians Really Evolving Due to Non-physician Clinicians Predominance in Staff Makeup in Sub-Saharan African Health Systems?; Comment on “Non-physician Clinicians in Sub-Saharan Africa and the Evolving Role of Physicians”

Health workforce shortages in Sub-Saharan Africa are widely recognized, particularly of physicians, leading the training and deployment of Non-physician clinicians (NPCs). The paper by Eyal et al provides interesting and legitimate viewpoints on evolving role of physicians in context of decisive increase of NPCss in Sub-Saharan Africa. Certainly, in short or mid-term, NPCs will continue to be a...

متن کامل

Model-driven risk analysis of evolving critical infrastructures

The protection and security of critical infrastructures are important parts of Homeland Defense. Adequate means for analyzing the security risks of such infrastructures is a prerequisite for properly understanding the security needs and for maintaining appropriate incident preparedness. Risk management is coordinated activities to direct and control an organization with regard to risk, and incl...

متن کامل

Tool-Supported Risk Modeling and Analysis of Evolving Critical Infrastructures

Risk management is coordinated activities to direct and control an organization with regard to risk, and includes the identification, analysis and mitigation of unacceptable risks. For critical infrastructures consisting of interdependent systems, risk analysis and mitigation is challenging because the overall risk picture can be strongly affected by changes in only a few of the systems. In ord...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2007