177,867 research outputs found
A Story of Parametric Trace Slicing, Garbage and Static Analysis
This paper presents a proposal (story) of how statically detecting
unreachable objects (in Java) could be used to improve a particular runtime
verification approach (for Java), namely parametric trace slicing. Monitoring
algorithms for parametric trace slicing depend on garbage collection to (i)
cleanup data-structures storing monitored objects, ensuring they do not become
unmanageably large, and (ii) anticipate the violation of (non-safety)
properties that cannot be satisfied as a monitored object can no longer appear
later in the trace. The proposal is that both usages can be improved by making
the unreachability of monitored objects explicit in the parametric property and
statically introducing additional instrumentation points generating related
events. The ideas presented in this paper are still exploratory and the
intention is to integrate the described techniques into the MarQ monitoring
tool for quantified event automata.Comment: In Proceedings PrePost 2017, arXiv:1708.0688
An Efficient Algorithm for Monitoring Practical TPTL Specifications
We provide a dynamic programming algorithm for the monitoring of a fragment
of Timed Propositional Temporal Logic (TPTL) specifications. This fragment of
TPTL, which is more expressive than Metric Temporal Logic, is characterized by
independent time variables which enable the elicitation of complex real-time
requirements. For this fragment, we provide an efficient polynomial time
algorithm for off-line monitoring of finite traces. Finally, we provide
experimental results on a prototype implementation of our tool in order to
demonstrate the feasibility of using our tool in practical applications
A decidable policy language for history-based transaction monitoring
Online trading invariably involves dealings between strangers, so it is
important for one party to be able to judge objectively the trustworthiness of
the other. In such a setting, the decision to trust a user may sensibly be
based on that user's past behaviour. We introduce a specification language
based on linear temporal logic for expressing a policy for categorising the
behaviour patterns of a user depending on its transaction history. We also
present an algorithm for checking whether the transaction history obeys the
stated policy. To be useful in a real setting, such a language should allow one
to express realistic policies which may involve parameter quantification and
quantitative or statistical patterns. We introduce several extensions of linear
temporal logic to cater for such needs: a restricted form of universal and
existential quantification; arbitrary computable functions and relations in the
term language; and a "counting" quantifier for counting how many times a
formula holds in the past. We then show that model checking a transaction
history against a policy, which we call the history-based transaction
monitoring problem, is PSPACE-complete in the size of the policy formula and
the length of the history. The problem becomes decidable in polynomial time
when the policies are fixed. We also consider the problem of transaction
monitoring in the case where not all the parameters of actions are observable.
We formulate two such "partial observability" monitoring problems, and show
their decidability under certain restrictions
Condition monitoring of an advanced gas-cooled nuclear reactor core
A critical component of an advanced gas-cooled reactor station is the graphite core. As a station ages, the graphite bricks that comprise the core can distort and may eventually crack. Since the core cannot be replaced, the core integrity ultimately determines the station life. Monitoring these distortions is usually restricted to the routine outages, which occur every few years, as this is the only time that the reactor core can be accessed by external sensing equipment. This paper presents a monitoring module based on model-based techniques using measurements obtained during the refuelling process. A fault detection and isolation filter based on unknown input observer techniques is developed. The role of this filter is to estimate the friction force produced by the interaction between the wall of the fuel channel and the fuel assembly supporting brushes. This allows an estimate to be made of the shape of the graphite bricks that comprise the core and, therefore, to monitor any distortion on them
Specification-Driven Predictive Business Process Monitoring
Predictive analysis in business process monitoring aims at forecasting the
future information of a running business process. The prediction is typically
made based on the model extracted from historical process execution logs (event
logs). In practice, different business domains might require different kinds of
predictions. Hence, it is important to have a means for properly specifying the
desired prediction tasks, and a mechanism to deal with these various prediction
tasks. Although there have been many studies in this area, they mostly focus on
a specific prediction task. This work introduces a language for specifying the
desired prediction tasks, and this language allows us to express various kinds
of prediction tasks. This work also presents a mechanism for automatically
creating the corresponding prediction model based on the given specification.
Differently from previous studies, instead of focusing on a particular
prediction task, we present an approach to deal with various prediction tasks
based on the given specification of the desired prediction tasks. We also
provide an implementation of the approach which is used to conduct experiments
using real-life event logs.Comment: This article significantly extends the previous work in
https://doi.org/10.1007/978-3-319-91704-7_7 which has a technical report in
arXiv:1804.00617. This article and the previous work have a coauthor in
commo
Improving Runtime Overheads for detectEr
We design monitor optimisations for detectEr, a runtime-verification tool
synthesising systems of concurrent monitors from correctness properties for
Erlang programs. We implement these optimisations as part of the existing tool
and show that they yield considerably lower runtime overheads when compared to
the unoptimised monitor synthesis.Comment: In Proceedings FESCA 2015, arXiv:1503.0437
Allen Linear (Interval) Temporal Logic --Translation to LTL and Monitor Synthesis--
The relationship between two well established formalisms for temporal reasoning is first investigated, namely between Allen's interval algebra (or Allen's temporal logic, abbreviated \ATL) and linear temporal logic (\LTL). A discrete variant of \ATL is defined, called Allen linear temporal logic (\ALTL), whose models are \omega-sequences of timepoints, like in \LTL. It is shown that any \ALTL formula can be linearly translated into an equivalent \LTL formula, thus enabling the use of \LTL techniques and tools when requirements are expressed in \ALTL. %This translation also implies the NP-completeness of \ATL satisfiability. Then the monitoring problem for \ALTL is discussed, showing that it is NP-complete despite the fact that the similar problem for \LTL is EXPSPACE-complete. An effective monitoring algorithm for \ALTL is given, which has been implemented and experimented with in the context of planning applications
On Synchronous and Asynchronous Monitor Instrumentation for Actor-based systems
We study the impact of synchronous and asynchronous monitoring
instrumentation on runtime overheads in the context of a runtime verification
framework for actor-based systems. We show that, in such a context,
asynchronous monitoring incurs substantially lower overhead costs. We also show
how, for certain properties that require synchronous monitoring, a hybrid
approach can be used that ensures timely violation detections for the important
events while, at the same time, incurring lower overhead costs that are closer
to those of an asynchronous instrumentation.Comment: In Proceedings FOCLASA 2014, arXiv:1502.0315
- …