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.
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A contrary-to-duty obligation (sometimes called a reparational duty) is a conditional obligation where the condition is forbidden, e.g. “if you have hurt your friend, you should apologise”, “if he is guilty, he should confess”, and “if she will not keep her promise to you, she ought to call you”. It has proven very difficult to find plausible formalisations of such obligations in most deontic systems. In this paper, we will introduce and explore a set of temporal alethic dyadic deontic systems, i.e., systems that include temporal, alethic and dyadic deontic operators. We will then show how it is possible to use our formal apparatus to symbolise contrary-to-duty obligations and to solve the so-called contrary-to-duty (obligation) paradox, a problem well known in deontic logic. We will argue that this response to the puzzle has many attractive features. Semantic tableaux are used to characterise our systems proof theoretically and a kind of possible world semantics, inspired by the so-called T× W semantics, to characterise them semantically. Our models contain several different accessibility relations and a preference relation between possible worlds, which are used in the definitions of the truth conditions for the various operators. Soundness results are obtained for every tableau system and completeness results for a subclass of them.
This work concerns issues related to automatic generation of logical specifications. Logical specifications can be extracted directly from developed software models. Received specification can be used in the process of a system formal verification using a deductive approach. The generated logical specification is just a set of temporal logie fonnulas as well as verified system properties are expressed in temporal logie. The extraction process is based on the idea of organizing the whole analyzed model as a set of certain design patterns of control flows. A method of automatic transformation of workflow design patterns to temporal logie formulas is proposed. These formulas constitute a logical specification and may be the first step towards a formal verification of system correctness using any method of the deduction-based reasoning. Applying the presented concepts enables bridging the gap between naturalness and intuitive of the deductive inference and the difficulty of its practical application in the case of software models.
PL
Praca dotyczy zagadnień związanych z automatyczną generacją i modelowaniem specyfikacji logicznej. Specyfikacja logiczna może być wygenerowana bezpośrednio z modeli oprogramowania. Tak uzyskana specyfikacja następnie może być wykorzystana w procesie formalnej weryfikacji przy wykorzystaniu podejścia dedukcyjnego. Wygenerowana specyfikacja reprezentowana jest przez zbiór formuł logiki temporalnej, również weryfikowane własności systemu mogą i powinny być wyrażone w logice temporalnej. Proces ekstrakcji opiera się na założeniu, aby cały analizowany model oprogramowania został zbudowany w oparciu o przyjęte, dowolne, ale najlepsze dla danej klasy zastosowań, wzorce projektowe. Została zaproponowana metoda automatycznej translacji wzorców projektowych (przepływów) do postaci formuł logiki temporalnej. Formuły te składają się na logiczną specyfikację i mogą stanowić pierwszy krok w kierunku formalnej weryfikacji poprawności systemów z wykorzystaniem dowolnej metody wnioskowania dedukcyjnego. Zastosowanie przedstawionych koncepcji umożliwia połączenie naturalności i intuicyjności samego wnioskowania logicznego oraz praktycznego zastosowania tych metod w przypadku modeli oprogramowania.
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.
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