5895211
Timed Communicating Object Z
This paper describes a timed, multithreaded object modeling notation for specifying real-time, concurrent, and reactive systems. The notation Timed Communicating Object Z (TCOZ) builds on Object Z's strengths in modeling complex data and algorithms, and on Timed CSP's strengths in modeling process control and real-time interactions. TCOZ Is novel in that it includes timing primitives, properly separates process control and data/algorithm issues and supports the modeling of true multithreaded concurrency. TCOZ is particularly well-suited for specifying complex systems whose components have their own thread of control. The expressiveness of the notation is demonstrated by a case study in specifying a multilift system that operates in real-time.
207130315
Formal Designs for Embedded and Hybrid Systems
The design of embedded and hybrid systems requires powerful mechanisms for modeling data, state, concurrency and real-time behaviour. The {first} part of this paper illustrates a powerful design notation Timed Communicating Object Z (TCOZ) that has both channel based and sensor/actuator based interfaces. We believe that TCOZ is well suited for presenting more complete and coherent design models for complex embedded and hybrid systems. However, the challenge is how to analyze and check these models with tools support. One effective approach is to project (transform) the design models into multiple domains, then to use existing specialized tools in those domains to perform the checking and analyzing tasks. The second part of this paper demonstrates one particular projection from TCOZ designs to Timed Automata (TA) models so that TA model checkers can be used to check time related properties.
18649413
Capturing periodic concurrent interactions of mission computer tasks
Safety critical systems, such as aviation systems controlled by software, often have hard real-time requirements. Producing the correct result at the right time is the fundamental goal of such systems. Formally specifying the system functions and the timing requirements is the crucial step towards achieving such a goal. Aviation systems often need to be modified or upgraded on a regular basis, i.e. functionality and timing constraints may be altered. Therefore, the formal specification of such systems needs to be easily reused, maintained and modified. This paper demonstrates how the task scheduling aspects of an aircraft mission computer can be formalised in TCOZ.
10062286
Integrating Object-Z with timed automata
When designing a complex system, Object-Z is a powerful logic-based language for modeling the system state aspects, and timed automata is an excellent graph-based notation for capturing timed control behaviour of the system. This paper presents an effective combination of the two techniques with novel composition and communication mechanisms. The combined notation enhances Object-Z with realtime modeling capability and also extends timed automata with enhanced structure and state modeling features.
5239234
The role of secondary attributes in formal object modelling
When modelling a large and complex system, clarity of the specification becomes an important factor. In object-oriented specification, the states of individual objects are captured by the values of their attributes. Frequently however, there are dependencies between the attributes of an object. An appropriate indication of which attributes are primary (independent) and which are secondary (dependent) can add significantly to clarity. This paper details the notion of secondary attributes, their roles and implications in formal object-oriented specification.
18404140
Deep Semantic Links of TCSP and Object-Z: TCOZ Approach
Abstract. Formal methods can be used in effective combination only if the semantic links between individual methods are clearly established. This paper discusses the semantic design of TCOZ, a language blended from Object-Z and TCSP. The semantic model adopted is the infinite timed failures model of TCSP, extended to include initial state and update events for modelling operations on internal state. An infinite trace model has been used so as to ensure proper account is taken of the potentially unbounded non-determinism allowed by Z schemas.
3121999
A pattern-based approach to structural design composition
This paper describes an approach to component-based software engineering based on a formal description of design patterns. The architectural design information, captured by design patterns, is made explicit and represented in a declarative way, being packaged into tangible artifacts as building block design components in the development process. These design component descriptions can be instantiated, adapted, assembled, implemented, and maintained. Furthermore, we can use these representations to reason about properties related to the combination of design components. We illustrate the utility of our approach through a case study involving various design patterns.
38191842
Modeling of End-to-End Transmission of Astronomical Images over Lossy Network
17533115
A Behavioral Analysis Approach to Pattern-Based Composition
This paper introduces a rigorous analysis approach to software design composition based on automated verification techniques. We show how to represent, instantiate and integrate design components, and how to find design composition errors using model checking techniques. We illustrate our approach with a Web-based hypermedia case study since hypermedia documents and systems are now becoming complex software applications, which are component-based.
18879642
A Component Framework for Resource Management Systems
Resource management is a complex process in many business organizations. Current solutions are typically in a case-by-case manner. In this paper, we present a general component framework for resource management such that different applications can be instantiated from the framework.
6426341
Event-based blackboard architecture for multi-agent systems
Developing large multi-agent systems is a complex task involving the processes of the requirement, architecture, design and implementation of these systems. In particular, the architectural design is critical to cope with the increasing size and complexity of these systems. The multi-agent system that accesses a central repository is typically based on the blackboard architectural pattern. However, the control strategies of the agents are inherently complex. In this paper, we present an event-based control strategy to manage the access of central repository by multi-agents. In this approach, the blackboard pattern is composed with the implicit invocation pattern to separate the control policies from the control component so that the architecture is ease of evolution, reuses and changes.