Systems Engineering at ISR. And why it's important!

Systems Engineering Research and Education at ISR. Our focus for Systems Engineering Research and Education is "systems analysis and trade-off." Student Population We provide graduate-level systems engineering education for both students and practicing engineers. MSSE (27): Full-time study leading to a first career position. Established in the Fall, 1987. ENPM (23): Mid-career professionals looking to balance professional experience with academic training. Established in mid 1990s. Age Profile. MSSE: 23-25; ENPM 27-32. Why Systems Engineering is Important? Over the past fifteen years there have been several important reasons and developments that have rendered systems engineering educational programs and methods critical. They are: Rapid changes in technology; Fast time-to-market most critical; Increasing pressure to lower costs; Increasing higher performance requirements; Increasing complexity of systems/products; Increased presence of embedded information and automation systems; and Failures due to lack of systems engineering. 70% of product and system failures are due to bad or no Systems Engineering effort, as our industry advisors (General Electric, Lockheed Martin, Northrop Grumman) and collaborators have frequently stated. NSF CRCD Project Challenges Identify and address key research challenges facing "synthesis of engineering systems." How to codify this knowledge into courses and provide systematic methodologies and tools for the "synthesis of engineering systems?" How to find a practical way of using web technology to enhance: (a) classroom instruction, and (b) self-guided "post-training" instruction.

Major Challenges facing the Practicing Systems Engineer

Synthesis from Modular Components The prevalence of synthesis from modular components is no longer true just for aerospace, defense and large government contracts (systems engineering started with Aerospace Engineering). Instead it is required in all commercial designs and operations. This so-called ``systems integration'' has become key and perhaps the most profitable engineering practice. Support for Team Development Teams of experts from multiple disciplines/domains working together on the solution of complex problems is a common requirement in industry today (e.g., integrated product teams (IPTs)). We need to maintain a shared view of the project objectives, and at the same time focus on specific tasks. A key challenge is avoiding communication and interpretation problems -- everyone needs to know what they are supposed to be working on, and when it's due! Growing Importance of Information-Driven Systems In the past, systems have been seen from an operations point of view, where information and communications have been regarded as the supply of services necessary for the system to operate in pre-defined ways. Nowadays, there is a rapidly evolving trend towards the team development of large-scale information-dominated systems, which exploit COTS and communications technologies, have superior performance and reliability, and are derived in response to various types of information drawn from a wide array of sources. Large Volumes of Heterogeneous Data Current and future data are in large volumes (not all relevant), numerically intensive (often requiring parallel algorithms for processing), multidimensional, heterogeneous, distributed, typically worked on specialized search engines, and represent multiple views (to the various users from engineering team members, to marketing, to sales people, to management, and to customers).

Our Strategy and Approach to Systems Engineering Practice

Promote Function-Architecture Co-Design and Orthogonalization of Design Concerns Emphasize function-architecture co-design. System design alternatives are created by mapping models of system behavior onto tentative system structures. System evaluation and ranking/optimization procedures eliminate the inferior solutions. Figure: Evaluation, Ranking, Optimization and Trade-Off Analysis for System Design Alternatives In the design of complex engineering systems, "orthogonalization of concerns" simplifies the difficulty in exploring the space of design alternatives. Promote Quantitative Procedures for System Evaluation, Optimization and Trade-Off Develop sophisticated algorithmic, mathematical and quantitative methods implementable in modern software environments for system evaluation, ranking, optimization and trade-off analysis. Promote use of Technology-Independent System-Level Design Representations We want to create system-level design representation that are not tied to an underlying implementation technology. This can be achieved, in part, through separate representations for the logical and physical design. Figure : Provision for Fomalization and Early Detection of Errors Goal. Hardware and software implementations and specific technology selections are ``pushed'' near the very end (i.e., delayed as long as possible), but are performed once and must work flawlessly. Promote Reuse at all levels of Abstraction Abstract multiple disciplines to properly annotated information representations. This is the only way to allow communication among disciplines and multiple contextual views. Figure : Layers of Abstraction in Reuse A "general-purpose" information representation that can describe all aspects of system behavior and structure is currently unavailable. Hence, systems must work with multiple information abstractions. For example: At a high-level of abstraction. Unified Modeling Language (UML), Technical drawings. At a lower-level of abstraction. Three dimensional geometric models, engineering simulation packages ... etc. Promote Use of Object-Relational Database Storage. Enable reuse of designs, architectures and business processes through object-relational database storage. Figure : Business Processes supported by Technology Object-relational database storage can be the foundation for "platform-based design" of satellite systems. Promote Automation for Multidisciplinary Information-Based Design Systems engineers at NASA face several major challenges (e.g., synthesis of systems from modular components; support for team development in multi-national projects; growing importance of systems dominated by data/information). We need to find ways to automate the capture and processing of data/information relevant to engineering system development. Figure : Requirements Engineering Processes supported by Semantic Web Technology Systems engineering development processes (e.g., requirements engineering) and the Semamtic Web are both "chaotic systems-of-systems." Systems engineering methodologies and tools for automation can benefit from advances in Semamtic Web Technology!

Key Technical Areas

Key Technical Areas Object modeling of systems using the Unified Modeling Language (UML) and automation of model-based system behavior simulation. Semi-formal and formal languages for the representation of system requirements, system specifications, and allocation flowdown in heterogeneous (from the physical layer perspective) hierarchies. Object-relational databases and multiple views (engineering and others) of system data. Quantitative procedures for trade-off analysis when (mixed) Boolean and numeric variables are present. Validation and verification by quantitative treatment of tolerances and convex analysis. Pathway from Research to Curriculum Development

University, Industry and Publishing Components of NSF-CRCD

Figure : University, Industry and Publishing components of NSF CRCD

Proposed Architecture for NSF CRCD Materials

Tutorials will be prepared in multiple formats and arranged into the following multi-layer architecture. Figure : Proposed Architecture for NSF CFCD Materials Modules of slides will be prepared for each chapter of notes and case study. Chapter and case study material will be supported by lower-level case study examples, online material for UML notation and semantics, and so forth.

Case Study Framework and Relevant UML Diagrams

Case Study Framework We would like all of our case studies to have a common system development and design framework: Problem Statement Generation of User Requirements Simplified Models of System Behavior Modeling the System Structure Creating the Logical Design Creating the Physical Design Evaluation and Ranking of System Design Alternatives System Optimization and Tradeoff Analysis Generalizing the Problem Domain for System Reuse References and Web Resources Small Case Study Problems Small case study problems will be developed by students in the MSSE program. Systems Development and Design of a 4-way Traffic Intersection . Systems Development and Design of a Portable CD Player (Tarun Luthra). Large Case Study Investigations Larger case study investigations (and associated research) will be conducted in collaboration with US industry. Integrating Geospatial Object Models with the Semantic Web (Michael Casey). Requirements Engineering for 3D Model-Based Engineering. (Dr. Bernie Frankpitt). Systems Issues for Bioinformatics and Databases (Prof. John Baras).

Classification of UML Diagrams Major Area View Diagram System Structure Static View Class Diagram Use Case View Use Case Diagram Implementation View Component Diagram Deployment View Deployment Diagram System Behavior State Machine View Statechart Diagram Activity View Activity Diagram Interaction View Sequence Diagram Collaboration Diagram Table : Classification of UML Diagrams for each Major Area Tutorial and Case Study Support Material UML Diagram Notation and Semantics Guidelines for UML Diagram Development Glossary of Terms

Mechanisms for Web-based Systems Engineering Training

Lessons Learned from Company ABC Company ABC has in-house training for a sophisticated systems engineering tool. Training focuses on step-by-step procedures for using the tool to accomplish specific tasks. At the end of the training, employees can use the tool to work through simple tasks, but have extreme difficulty in connecting high-level systems engineering (and organizational) processes to lower-level tasks. Connecting High-level Processes to Lower-level Tasks Employees need to see how high-level systems engineering (and organizational) processes are supported by tools. How to make this connection? We need an expressive notation for bridging the gap between high-level learning objectives and systems engineering processes, and lower-level task- and tool-oriented procedures.

Lessons Learned from Company XYZ

Figure : Architecture of Training Material Contents

What did we observe and learn from our training classes at XYZ?

1. Systems engineering is a team activity -- training needs to support multiple viewpoints, levels of experience, and backgrounds.

2. Systems engineering processes make use of many different entity types (e.g., primary and derived requirements; traceability links; various models of system behavior and system structure), sometimes connected in complicated ways.

3. Training materials are linear -- but systems concepts are best organized into a variety of architectures. See the adjacent figure.

4. Too many pages! Too many links! Readers feel overwhelmed. They jump around material and gloss over content rather than learning it.

5. Students need to see how new systems engineering concepts can be applied to applications they are familiar with. (i.e., if you're at a company that makes trains, you need a case study on trains).

Challenge

1. Need to find ways of using web technology to enhance quality of learning. Otherwise, whole exercise is a waste of time.

2. How to work with XYZ's businesses to create business-specific case studies?

Annotating Diagrams with Use Case Pathways

Observations Opening a large folder of training materials for the first time is somewhat akin to your first visit to NYC -- it's intimidating. In both cases, it's easy to get lost unless you have a teacher, friend or map to guide you around. Traditional media use the "table of contents" and "subject and author index" as guides. If you don't have a friend to show you around NYC, it's a good idea to take a guided tour. So why not create a similar mechanism for web-based training material? Anatomy of a Lesson : Learning Objectives lead to Pathways across Diagrams Features of a Good Guided Tour The tour visits the most important parts of the city, and doesn't take too long. Along the way, the tour guide brings "points of interest" to your attention.

Annotating Diagrams with Use Case Pathways

Definition of a Use Case Pathway A use case pathway is a wiggly line that enables a student to visualize scenarios threading through a system, without the scenarios being specified in great detail. Pathways will help students answer quenstions like: Where did I come from? Show me what to do now? What should I do next?

Annotating Diagrams with Use Case Pathways

Figure : Adding Pathways to Tutorial Diagrams

Connecting Use Case Pathways to Discipline-Specific Activities

Near- and Medium-Term Research and Software Development

Phase 1 : Explore feasibility of XML to Java Applet Pathway (Sep't 1999 - August 2000) Design XML vocabulary, tag set structure for markup of diagrams and diagram pathways, and XML-to-Java source code compiler. Phase 2 : Develop Platform-Independent Diagram Editor (June, 2001 -- present) Create a click-and-drop editor for development of "Collections of Java-Enabled Diagrams." Knowledge Capture for Systems Engineering is enabled through: (1) Diagram annotation features, (2) Links to heterogenous data and information sources on the web, and (3) File and database storage. Figure: Tools and Technologies for Knowledge Capture in Systems Engineering We are currently working on the right-hand side of this diagram. Future versions of the editor will import of XML representations of diagrams, requirements, and systems stored in commerical databases (e.g., Oracle).

Phase 3 : Requirements Engineering Methodologies and Tools (April 2002 - present ) Critical Assessment of Present-Day Systems Engineering Tools (e.g., DOORS and SLATE). How do we capture and represent knowledge through requirements engineering activities? Figure: Requirements Engineering Work Breakdown Structure (WBS). Figure: Requirements Engineering WBS and Industry Toolset Weakensses. (For details, see Ramesh and Jarke, 2001) Specific Limitations of Present-Day Tools (Selberg, 2002) Thick Descriptions. Current tools lack the ability to store informal representations (i.e., so-called thick descriptions) of systems conveying information along subtle or implied lines. Model Driven Trace Capture and Usage. Current tools lack mechansms for "easy linking" of models into the design environment (e.g., SLATE). Abstraction Mechanisms. Current tools lack the ability to search and explore requirements at various levels of abstraction. Inference Services. The lack of "inference services" in the work breakdown structure impacts the systems engineering process in several ways. Current tools are incapable of analyzing requirements for completeness or consistency. Search mechanisms are limited to keywords, which can be limiting for custom jargon in multidisciplinary and multilingual projects. Transfer of Semantic Web Technologies to Tools for Requirments Engineering What is the Minumum Level of Semantic Web Technology that can mitigate (and hopefully overcome) limitations in present-day tools? Figure: Requirements Engineering WBS (Create Branch) to Semantic Layer Cake (Selberg, 2002). Figure: Requirements Engineering WBS (Use Branch) to Semantic Layer Cake (Selberg, 2002). References Ramesh B., and Jarke M., "Toward Reference Models for Requirements Traceability," IEEE Transactions on Software Engineering, Vol. 27., No. 1., January 2001, pp. 58-93. Selberg S., "Requirements Engineering and the Semantic Web," M.S. Thesis, Institute for Systems Research, University of Maryland, College Park, MD 20742, April 2002.

Overview of XML and Java Technology

Features and Benefits of XML The eXtended markup language (XML) is a metalanguage -- that is, a language for describing other languages -- that allows people and computers to search for and exchange scientific, engineering and business data/information. Web page content is separated from presentation -- applications decide how the data will be displayed. XML allows for custom interpretation of data sets (write once, publish anywhere). Features and Benefits of Java Java is an object-oriented programming language that compiles into a platform-independent bytecode. Therefore, Java bytecode is portable, and we can reuse software components across heterogeneous computing platforms (write once, run anywhere).

Overview of Java and XML Technology

XML Document to Application Pathway

Step-by-Step Development

1. Design XML tagset and allowable hierarchy for combination of tags.
2. Design a data type definition (DTD) file (or XML schema file).
3. Create parser to transform XML document into (internal) tree structure.
4. Develop application code to travserse tree structure and generate application-specific output (in our case, this will be Java source code).

Phase 1: The JaDia Markup Language

The JaDia Markup Language has 12 elements: <chart> <graph> <edge> <node> <frame> <framenode> <path> <pathedge> <link> <hint> <image> <text>

Figure : Components of the JaDia Markup Language

Screendumps of Drag-and-Drop Editor

Figure : Drag-and-Drop Editor

Figure : Property Window

Opportunities for Joint Research and Development

Systems Engineering Education We are keen to collaborate with NASA on development and delivery of Systems Engineering Curricula. Research and Development Task 1. Generalize and implement pathways concepts to new applications (e.g., low-end traceability) and new tools (6 months work). Task 2. Design and implement XML schema for system descriptions. Develop software for file I/O of XML-based system descriptions (6 months work). Task 3. Database storage of web-based materials (6 months work). Ph.D. Research. Explore application of Semantic Web Technologies to Systems/Project Management (3 years work). Parallel activities supported by NSF-CRCD: Reformat "small case studies" to take advantage of diagram technology. Test and evaluate the new material in academic and industry enviroments. Identify situations where "Java-enabled diagram technology" will add value to web-based systems engineering. Candidates include: Step-by-step assembly procedures (e.g., for furniture assembly). For signposting task-based models of design processes. We expect that both areas will employ combination of network and hierarchy system structures -- the Java-enabled diagram technology can handle this!

Print Version: April 19, 2002.