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Efficient Model Checking of Safety Properties [chapter]

Timo Latvala
2003 Lecture Notes in Computer Science  
Safety properties are an interesting subset of general temporal properties for systems. In the linear time paradigm, model checking of safety properties is simpler than the general case, because safety properties can be captured by finite automata. This work discusses the theoretical and some of the practical issues related to model checking LTL properties. Our first contribution is a theorem relating abstraction for Coloured Petri nets as defined by Lakos [36] and preservation of safety
more » ... ies. We show that a subset of the safety properties are preserved for this abstraction framework. Our other contribution is an efficient algorithm for translating LTL safety properties to finite automata. Minor contributions include new proofs for some old complexity results regarding LTL and safety properties. The implementation of the translation algorithm is also experimentally evaluated. Experiments support the feasibility of the approach. In many tests the implementation is quite competitive when compared to algorithms translating full LTL to Büchi automata. The implementation can also check if an LTL formula is pathologic. The check performs well according to experiments.
doi:10.1007/3-540-44829-2_5 fatcat:zlkczcjjdfeijoekb66ohrtpe4

LTL Model Checking for Modular Petri Nets [chapter]

Timo Latvala, Marko Mäkelä
2004 Lecture Notes in Computer Science  
Latvala and M.  ...  Latvala and M. MäkeläPresented by Deian Tabakov Modular Petri Nets.Petri Nets: Concurrency T. Latvala and M. MäkeläPresented by Deian Tabakov Modular Petri Nets...  ...  Latvala and M. MäkeläPresented by Deian Tabakov Modular Petri Nets...  ... 
doi:10.1007/978-3-540-27793-4_17 fatcat:nxopqdx7nbcgpjbqpmpo6b7zwu

Simple Bounded LTL Model Checking [chapter]

Timo Latvala, Armin Biere, Keijo Heljanko, Tommi Junttila
2004 Lecture Notes in Computer Science  
We present a new and very simple translation of the bounded model checking problem which is linear both in the size of the formula and the length of the bound. The resulting CNF-formula has a linear number of variables and clauses.
doi:10.1007/978-3-540-30494-4_14 fatcat:ksc7sm55hngtdhscw55f4kgnxa

Incremental and Complete Bounded Model Checking for Full PLTL [chapter]

Keijo Heljanko, Tommi Junttila, Timo Latvala
2005 Lecture Notes in Computer Science  
Bounded model checking is an efficient method for finding bugs in system designs. The major drawback of the basic method is that it cannot prove properties, only disprove them. Recently, some progress has been made towards proving properties of LTL. We present an incremental and complete bounded model checking method for the full linear temporal logic with past (PLTL). Compared to previous works, our method both improves and extends current results in many ways: (i) our encoding is incremental,
more » ... resulting in improvements in performance, (ii) we can prove non-existence of a counterexample at shallower depths in many cases, and (iii) we support full PLTL. We have implemented our method in the NuSMV2 model checker and report encouraging experimental results.
doi:10.1007/11513988_10 fatcat:zgdog3jwsje6zesqwcjj7zvt3e

Model Checking LTL Properties of High-Level Petri Nets with Fairness Constraints [chapter]

Timo Latvala
2001 Lecture Notes in Computer Science  
doi:10.1007/3-540-45740-2_15 fatcat:hfvn554qzvdallxzbmnowwztpu

Bounded Model Checking for Weak Alternating Büchi Automata [chapter]

Keijo Heljanko, Tommi Junttila, Misa Keinänen, Martin Lange, Timo Latvala
2006 Lecture Notes in Computer Science  
The prototype implementation as well as the experiments are available at http://www.tcs.hut.fi/˜timo/ cav2006.  ... 
doi:10.1007/11817963_12 fatcat:auy4iqgjrbay3erq77md7r76i4

Supporting Reuse in Event B Development: Modularisation Approach [chapter]

Alexei Iliasov, Elena Troubitsyna, Linas Laibinis, Alexander Romanovsky, Kimmo Varpaaniemi, Dubravka Ilic, Timo Latvala
2010 Lecture Notes in Computer Science  
Recently, Space Systems Finland has undertaken formal Event B development of a part of on-board software for the BepiColombo space mission. As a result, lack of modularization mechanisms in Event B has been identified as a serious obstacle to scalability. One of the main benefits of modularization is that it allows us to decompose system models into components that can be independently developed. It also helps to manage complexity of models that in the industrial setting are usually very large
more » ... nd difficult to comprehend. On the other hand, modularization enables reuse of formally developed components in the formal product line development. In this paper we propose a conservative extension of Event B formalism to support modularization. We demonstrate how our approach can support reuse in the formal development in the space domain.
doi:10.1007/978-3-642-11811-1_14 fatcat:774gqpcnx5bgdovlgfhqcslau4

Simple Is Better: Efficient Bounded Model Checking for Past LTL [chapter]

Timo Latvala, Armin Biere, Keijo Heljanko, Tommi Junttila
2005 Lecture Notes in Computer Science  
Our implementation and files related to the experiments are available at http://www.tcs.hut.fi/˜timo/vmcai2005/.  ... 
doi:10.1007/978-3-540-30579-8_25 fatcat:d6apzy6t7zfrdjelzvnorpgs2i

Developing Mode-Rich Satellite Software by Refinement in Event B [chapter]

Alexei Iliasov, Elena Troubitsyna, Linas Laibinis, Alexander Romanovsky, Kimmo Varpaaniemi, Dubravka Ilic, Timo Latvala
2010 Lecture Notes in Computer Science  
To ensure dependability of on-board satellite systems, the designers should, in particular, guarantee correct implementation of the mode transition scheme, i.e., ensure that the states of the system components are consistent with the global system mode. However, there is still a lack of scalable approaches to formal verification of correctness of complex mode transitions. In this paper we present a development of an Attitude and Orbit Control System (AOCS) undertaken within the ICT DEPLOY
more » ... t. AOCS is complex mode-rich system, which has an intricate mode-transition scheme. We show that re refinement in Event-B provides the engineers with a scalable formal technique that enables both development of mode-rich systems and proof-based verification of their mode consistency. Abstract To ensure dependability of on-board satellite systems, the designers should, in particular, guarantee correct implementation of the mode transition scheme, i.e., ensure that the states of the system components are consistent with the global system mode. However, there is still a lack of scalable approaches to formal verification of correctness of complex mode transitions. In this paper we present a development of an Attitude and Orbit Control System (AOCS) undertaken within the ICT DEPLOY project. AOCS is complex mode-rich system, which has an intricate mode-transition scheme. We show that re refinement in Event-B provides the engineers with a scalable formal technique that enables both development of mode-rich systems and proof-based verification of their mode consistency.
doi:10.1007/978-3-642-15898-8_4 fatcat:rpqfiozucnbfhjwvam2b5427ci

Population-level indicators associated with hormonal contraception use: a register-based matched case–control study

Elena Toffol, Oskari Heikinheimo, Anna But, Antti Latvala, Timo Partonen, Jari Haukka
2021 BMC Public Health  
Background Monitoring factors related to hormonal contraception (HC) use is essential to evaluating public health strategies and promoting access to contraception. We aimed to examine municipal social and health indicators of HC use at the population level, and to identify patterns of inequality across Finnish municipalities. Methods We identified all women (15–49 years) with a redeemed HC prescription in Finland in 2017 (n = 294,445), and a control group of non-users. Municipal social and
more » ... h indicators at the population level were retrieved from the nationwide Statistics and Indicator Bank. Differences between the groups across 309 municipalities were calculated, and associations of municipal-specific proportions of HC users with municipal-specific indicators were studied using LASSO (Least Absolute Shrinkage and Selection Operator) models. Results Sociodemographic differences between HC users and non-users were non-homogenous across municipalities. Indicators positively associated with HC use included: larger population and higher proportions of population aged 16–24 years, of household-dwelling units with one person, of persons with higher education, and of divorces among those aged 25–64. Lower HC use was associated with higher proportions of Swedish-speaking population, of those aged 7–15 years, of young people not in education/training, and of household-dwelling units in overcrowded conditions. Lower HC use was also associated with indicators of outpatient and inpatient healthcare, and of municipal finances in welfare and healthcare. Conclusions Sociodemographic differences in relation to HC use exist across Finnish municipalities. Municipal indicators of social structure, health and welfare, and investment in and use of healthcare services are related to HC use.
doi:10.1186/s12889-021-10512-6 pmid:33678190 fatcat:tvz5lim2mza5leh3g7aeadhb24

On Scaling Multi-Agent Task Reallocation Using Market-Based Approach

Rajesh K. Karmani, Timo Latvala, Gul Agha
2007 First International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2007)  
Multi-agent systems (MAS) provide a promising technology for addressing problems such as search and rescue missions, mine sweeping, and surveillance. These problems are a form of the computationally intractable Multi-Depot Traveling Salesman Problem (MDTSP). We propose a novel market-based approach, called Market-based Approach with Look-ahead Agents (MALA), to address the problem. In MALA, agents use look ahead to optimize their behavior. Each agent plans a preferred, reward-maximizing tour
more » ... itself using our proposed algorithm which is based on the Universal TSP algorithm. The agent then uses the preferred tour to evaluate potential trades with other agents in linear time -a necessary prerequisite for scalability of market-based approach. We use simulations in a two dimensional world to study the performance of MALA and compare it with O-contracts and TraderBots, respectively, a centralized approach and a distributed approach. Experiments suggest that MALA efficiently scales to thousands of tasks and hundreds of agents in terms of both computation and communication complexity, while delivering relatively good-quality but approximate solutions. *
doi:10.1109/saso.2007.41 dblp:conf/saso/KarmaniLA07 fatcat:jlvwzz4q6vg75f5t6sob733xai

Associations between hormonal contraception use, sociodemographic factors and mental health: a nationwide, register-based, matched case–control study

Elena Toffol, Anna But, Oskari Heikinheimo, Antti Latvala, Timo Partonen, Jari Haukka
2020 BMJ Open  
ObjectivesSociodemographic and mental health characteristics are associated with contraceptive choices. We aimed to describe the sociodemographic, reproductive and mental health characteristics of all fertile-aged women in Finland who used hormonal contraception (HC) in 2017.DesignA nationwide, register-based study.SettingAll women living in Finland in 2017; data from the Care Register of Health Care, Medical Birth Register, Population Register Centre, Prescription Centre, Register of Induced
more » ... ortions.ParticipantsAll women aged 15–49 with one redeemed HC prescription in 2017 (n=294 356), and a same-sized, age-matched and residence-matched, control group of non-users.OutcomesRates of HC use; associations between HC use and mental disorders, sociodemographic and reproductive characteristics.Results25.8% of women aged 15–49 years used HC. Women with the lowest socioeconomic levels had lower odds of using HC than women with upper-level statuses (OR, 95% CI students: 0.97, 0.94 to 0.99; entitled to pension: 0.66, 0.63 to 0.69; other: 0.87, 0.85 to 0.89; unknown: 0.90, 0.85 to 0.90). Women with the highest education (secondary: 1.46, 1.43 to 1.48; tertiary: 1.64, 1.58 to 1.70; academic: 1.60, 1.56 to 1.63) and income (second quarter: 1.57, 1.54 to 1.60; third quarter: 1.85, 1.82 to 1.89; fourth quarter: 2.01, 1.97 to 2.06), and unmarried women had higher odds of using HC than women with the lowest education and income levels, and married (0.61, 0.60 to 0.62), divorced (0.86, 0.84 to 0.88), widowed (0.73, 0.65 to 0.83) or other marital status women (0.26, 0.22 to 0.30).Parous women (0.70, 0.69 to 0.71), those with previous induced abortion(s) (0.91, 0.89 to 0.92) or recent eating (0.68, 0.62 to 0.75) or personality (0.89, 0.79 to 0.97) disorders had lower odds of HC use. Absolute risk differences between women with and without mental disorders ranged from 3.1% (anxiety disorders) to 10.1% (eating disorders).ConclusionsA quarter of the fertile-aged women use HC in Finland. Sociodemographic disparities persist in relation to HC use, although of small effect size. HC use is less common among women suffering from severe to moderate psychiatric disorders, especially eating disorders.
doi:10.1136/bmjopen-2020-040072 pmid:33060091 fatcat:apfrtaz5mvd67l2qj4h3rmtcoq

Live Lactobacillus rhamnosus and Streptococcus pyogenes differentially regulate Toll-like receptor (TLR) gene expression in human primary macrophages

Minja Miettinen, Ville Veckman, Sinikka Latvala, Timo Sareneva, Sampsa Matikainen, Ilkka Julkunen
2008 Journal of Leukocyte Biology  
Macrophages are phagocytes that recognize bacteria and subsequently activate appropriate innate and adaptive immune responses. TLRs are essential in identifying conserved bacterial structures and in initiating and mediating innate immune responses. In this work, we have characterized TLR gene expression in human monocyte-derived macrophages in response to stimulation with two live Gram-positive bacteria, a human commensal and probiotic Lactobacillus rhamnosus GG (LGG), and an important human
more » ... hogen Streptococcus pyogenes. LGG and S. pyogenes enhanced TLR2 expression in macrophages. LGG and S. pyogenes also required TLR2 for NF-B activation. Only pathogenic S. pyogenes was able to up-regulate TLR3 and TLR7 gene expression. This up-regulation was dependent on IFN-␣/␤, as neutralizing anti-IFN-␣/␤ antibodies reduced S. pyogenes-induced TLR3 and TLR7 mRNA expression. Our results show that despite similarities, TLR responses of macrophages differ for a Gram-positive probiotic and a pathogen. Our data suggest that macrophages can discriminate between probiotic and pathogenic bacteria by IFNmediated TLR gene regulation.
doi:10.1189/jlb.1206737 pmid:18625909 fatcat:5xdwevgzinb3fltieck76b4r34

Linear Encodings of Bounded LTL Model Checking

Armin Biere, Keijo Heljanko, Tommi Junttila, Timo Latvala, Viktor Schuppan, Kousha Etessami
2006 Logical Methods in Computer Science  
We consider the problem of bounded model checking (BMC) for linear temporal logic (LTL). We present several efficient encodings that have size linear in the bound. Furthermore, we show how the encodings can be extended to LTL with past operators (PLTL). The generalised encoding is still of linear size, but cannot detect minimal length counterexamples. By using the virtual unrolling technique minimal length counterexamples can be captured, however, the size of the encoding is quadratic in the
more » ... cification. We also extend virtual unrolling to Buchi automata, enabling them to accept minimal length counterexamples. Our BMC encodings can be made incremental in order to benefit from incremental SAT technology. With fairly small modifications the incremental encoding can be further enhanced with a termination check, allowing us to prove properties with BMC. Experiments clearly show that our new encodings improve performance of BMC considerably, particularly in the case of the incremental encoding, and that they are very competitive for finding bugs. An analysis of the liveness-to-safety transformation reveals many similarities to the BMC encodings in this paper. Using the liveness-to-safety translation with BDD-based invariant checking results in an efficient method to find shortest counterexamples that complements the BMC-based approach.
doi:10.2168/lmcs-2(5:5)2006 fatcat:udjtwahnfzft7og3he5s5ntneu

Examining User Experience in an Augmented Reality Adventure Game: Case Luostarinmäki Handicrafts Museum [chapter]

Kaapo Seppälä, Olli I. Heimo, Timo Korkalainen, Juho Pääkylä, Jussi Latvala, Seppo Helle, Lauri Härkänen, Sami Jokela, Lauri Järvenpää, Frans Saukko, Lauri Viinikkala, Tuomas Mäkilä (+1 others)
2016 IFIP Advances in Information and Communication Technology  
doi:10.1007/978-3-319-44805-3_21 fatcat:ihttt4sh2ndepg62kqclfcmpoe
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