Radosław Klimek

A system for deduction-based formal verification of workflow-oriented software models

Abstract The work concerns formal verification of workflow-oriented software models using the deductive approach. The formal correctness of a model’s behaviour is considered. Manually building logical specifications, which are regarded as a set of temporal logic formulas, seems to be a significant obstacle for an inexperienced user when applying the deductive approach. A system, along with its architecture, for deduction-based verification of workflow-oriented models is proposed. The process inference is based on the semantic tableaux method, which has some advantages when compared with traditional deduction strategies. The algorithm for automatic generation of logical specifications is proposed. The generation procedure is based on predefined workflow patterns for BPMN, which is a standard and dominant notation for the modeling of business processes. The main idea behind the approach is to consider patterns, defined in terms of temporal logic, as a kind of (logical) primitives which enable the transformation of models to temporal logic formulas constituting a logical specification. Automation of the generation process is crucial for bridging the gap between the intuitiveness of deductive reasoning and the difficulty of its practical application when logical specifications are built manually. This approach has gone some way towards supporting, hopefully enhancing, our understanding of deduction-based formal verification of workflow-oriented models.

FORMAL ANALYSIS OF USE CASE DIAGRAMS

Use case diagrams play an important role in modeling with UML. Careful modeling is crucialin obtaining a correct and efficient system architecture. The paper refers to the formalanalysis of the use case diagrams. A formal model of use cases is proposed and its constructionfor typical relationships between use cases is described. Two methods of formal analysis andverification are presented. The first one based on a states’ exploration represents a modelchecking approach. The second one refers to the symbolic reasoning using formal methodsof temporal logic. Simple but representative example of the use case scenario verification isdiscussed.

Modeling Context-Aware and Agent-Ready Systems for the Outdoor Smart Lighting

Smart lighting systems considered as context-awareness systems are challenging. The use of advanced technology for street lighting allows to achieve a number of potential benefits of improving the efficiency of lighting, enhance the ability to monitor and control street lighting. A context-aware based system in architecture for street lighting control dealing with intelligent software applications in pervasive computing has been proposed. Some diagrams in the UML language are extended by some elements of the CML language in order to provide possibilities to design and verify behaviour of context-aware-based systems.

Proposal of a multiagent-based smart environment for the IoT.

This work relates to context-awareness of things that belong to IoT networks. Preferences understood as a priority in selection are considered, and dynamic preference models for such systems are built. Preference models are based on formal logic, and they are built on-the-fly by software agents observing the behavior of users/inhabitants, and gathering knowledge about preferences expressed in terms of logical specifications. A 3-level structure of agents has been introduced to support IoT inference. These agents cooperate with each other basing on the graph representation of the system knowledge. An example of such a system is presented.

From Extraction of Logical Specifications to Deduction-Based Formal Verification of Requirements Models

The work relates to formal verification of requirements models using deductive reasoning. Elicitation of requirements has significant impact on the entire software development process. Therefore, formal verification of requirements models may influence software cost and reliability in a positive way. However, logical specifications, considered as sets of temporal logic formulas, are difficult to specify manually by inexperienced users and this fact can be regarded as a significant obstacle to practical use of deduction-based verification tools. A method of building requirements models, including their logical specifications, is presented step by step. Requirements models are built using some UML diagrams, i.e. use case diagrams, use case scenarios, and activity diagrams. Organizing activity diagrams into predefined workflow patterns enables automated extraction of logical specifications. The crucial aspect of the presented approach is integrating the requirements engineering phase and the automatic generation of logical specifications. Formal verification of requirements models is based on the deductive approach using the semantic tableaux reasoning method. A simple yet illustrative example of development and verification of a requirements model is provided.

State-Space Reduction through Preference Modeling ⋆

Automated planning for numerous co-existing agents, with uncertainty caused by various levels of their predictability, observability and autonomy, is a complex task. One of the most significant issues is related to explosion of the state space. This paper presents a formal framework which can be used to model such systems and proposes the use of formally-modeled agents’ preferences as a way of reducing the number of states. A detailed description of preference modeling is provided, and the approach is evaluated by examples.

Proposal of a context-aware smart home ecosystem

Smart homes are more and more popular since they are regarded as synonyms of an ideal and friendly environment. Novel aspects like context awareness and pro-activity are fundamental requirements for development of such systems. Smart scenarios enable switching devices in a desired way when a certain user activity considered as a trigger involves a system activity. Some smart scenarios are proposed. Context modeling and reasoning for smart homes is widely considered. A software architecture including web services is introduced and discussed.

Preference Models and Their Elicitation and Analysis for Context-Aware Applications

The work concerns building preference models when gathering system requirements and their formal analysis using the deductive approach. The selected UML diagrams are used for elicitation of preference models and temporal logic for their specification and verification. The proposed method makes preference modeling more reliable in the phase of requirements engineering. Preference models are based on predefined patterns. It enables the process of generating logical specifications for preference models to be automated.

Behavior Recognition and Analysis in Smart Environments for Context-Aware Applications

Providing accurate/suitable information on behaviors in smart environments is a challenging and crucial task in pervasive computing where context-awareness and pro-activity are of fundamental importance. Behavioral identifications enable to abstract higher-level concepts that are interesting to applications. This work proposes the unified logical-based framework to recognize and analyze behavioral specifications understood as a formal logic language that avoids ambiguity typical for natural languages. Automatically discovering behaviors from sensory data streams as formal specifications is of fundamental importance to build seamless human-computer interactions. Thus, the knowledge about environment behaviors expressed in terms of temporal logic formulas constitutes a base for the reactive and precise reasoning processes to support trustworthy, unambiguous and pro-active decisions for applications that are smart and context aware.Context-awareness is a one of the most important paradigm for nowadays/modern systems. It means sensing and reacting on environment which might be formed by things that belong to the IoT. The information that is derived from sensors constitutes, informally speaking, a kind of speech and language phrases, which could be expressed in terms of formal/temporal logic. Logic avoids ambiguity which is typical for natural languages. Such logical specifications, which could be the result of observing the behavior of users/inhabitants that belong to an environment, then might be used by context-aware applications. The knowledge expressed in terms of temporal logic formulas may constitute an input for formal reasoning processes to support decisions of applications that are context-aware and pro-active.

Deduction-Based Modelling and Verification of Agent-Based Systems for Data Integration

The work concerns the application of multi-agent systems to heterogeneous data integration, and shows how agent approach can be subjected to formal verification using a deductive approach. Since logical specifications are difficult to specify manually, a method for an automatic extraction of logical specifications, considered as a set of temporal logic formulae, is proposed. A simple example is provided.