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Compliance in Real Time Multiset Rewriting Models [article]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov and Carolyn Talcott
2018 arXiv   pre-print
The notion of compliance in Multiset Rewriting Models (MSR) has been introduced for untimed models and for models with discrete time. In this paper we revisit the notion of compliance and adapt it to fit with additional nondeterminism specific for dense time domains. Existing MSR with dense time are extended with critical configurations and non-critical traces, that is, traces involving no critical configurations. Complexity of related non-critical reachability problem is investigated. Although
more » ... this problem is undecidable in general, we prove that for balanced MSR with dense time the non-critical reachability problem is PSPACE-complete.
arXiv:1811.04826v1 fatcat:5frgkske6nbifpwvi77af4en34

Bounded memory protocols

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov
2014 Computer languages, systems & structures  
It is well-known that the Dolev-Yao adversary is a powerful adversary. Besides acting as the network, intercepting, decomposing, composing and sending messages, he can remember as much information as he needs. That is, his memory is unbounded. We recently proposed a weaker Dolev-Yao like adversary, which also acts as the network, but whose memory is bounded. We showed that this Bounded Memory Dolev-Yao adversary, when given enough memory, can carry out many existing protocol anomalies. In
more » ... ular, the known anomalies arise for bounded memory protocols, where although the total number of sessions is unbounded, there is only a bounded number of concurrent sessions and the honest participants of the protocol cannot remember an unbounded number of facts nor an unbounded number of nonces at a time. This led us to the question of whether it is possible to infer an upper-bound on the memory required by the Dolev-Yao adversary to carry out an anomaly from the memory restrictions of the bounded protocol. This paper answers this question negatively (Theorem 8).
doi:10.1016/j.cl.2014.05.003 fatcat:tsydq6ohhzcnnncl25te5drp4i

Semi-Local Integration Measure of Node Importance

Tajana Ban Kirigin, Sanda Bujačić Babić, Benedikt Perak
2022 Mathematics  
Numerous centrality measures have been introduced as tools to determine the importance of nodes in complex networks, reflecting various network properties, including connectivity, survivability, and robustness. In this paper, we introduce Semi-Local Intregation (SLI), a node centrality measure for undirected and weighted graphs that takes into account the coherence of the locally connected subnetwork and evaluates the integration of nodes within their neighbourhood. We illustrate SLI node
more » ... ance differentiation among nodes in lexical networks and demonstrate its potential in natural language processing (NLP). In the NLP task of sense identification and sense structure analysis, the SLI centrality measure evaluates node integration and provides the necessary local resolution by differentiating the importance of nodes to a greater extent than standard centrality measures. This provides the relevant topological information about different subnetworks based on relatively local information, revealing the more complex sense structure. In addition, we show how the SLI measure can improve the results of sentiment analysis. The SLI measure has the potential to be used in various types of complex networks in different research areas.
doi:10.3390/math10030405 fatcat:uu2cz5qm5jfpnemxwywvypsnju

Lexical Sense Labeling and Sentiment Potential Analysis Using Corpus-Based Dependency Graph

Tajana Ban Ban Kirigin, Sanda Bujačić Bujačić Babić, Benedikt Perak
2021 Mathematics  
This paper describes a graph method for labeling word senses and identifying lexical sentiment potential by integrating the corpus-based syntactic-semantic dependency graph layer, lexical semantic and sentiment dictionaries. The method, implemented as ConGraCNet application on different languages and corpora, projects a semantic function onto a particular syntactical dependency layer and constructs a seed lexeme graph with collocates of high conceptual similarity. The seed lexeme graph is
more » ... red into subgraphs that reveal the polysemous semantic nature of a lexeme in a corpus. The construction of the WordNet hypernym graph provides a set of synset labels that generalize the senses for each lexical cluster. By integrating sentiment dictionaries, we introduce graph propagation methods for sentiment analysis. Original dictionary sentiment values are integrated into ConGraCNet lexical graph to compute sentiment values of node lexemes and lexical clusters, and identify the sentiment potential of lexemes with respect to a corpus. The method can be used to resolve sparseness of sentiment dictionaries and enrich the sentiment evaluation of lexical structures in sentiment dictionaries by revealing the relative sentiment potential of polysemous lexemes with respect to a specific corpus. The proposed approach has the potential to be used as a complementary method to other NLP resources and tasks, including word disambiguation, domain relatedness, sense structure, metaphoricity, as well as a cross- and intra-cultural discourse variations of prototypical conceptualization patterns and knowledge representations.
doi:10.3390/math9121449 fatcat:7skucpa3xzgnhkwfc3rkc6i6ci

Bounded Memory Dolev-Yao Adversaries in Collaborative Systems [chapter]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov
2011 Lecture Notes in Computer Science  
This paper extends existing models for collaborative systems. We investigate how much damage can be done by insiders alone, without collusion with an outside adversary. In contrast to traditional intruder models, such as in protocol security, all the players inside our system, including potential adversaries, have similar capabilities. They have bounded storage capacity, that is, they can only remember at any moment a bounded number of symbols. This is technically imposed by only allowing
more » ... ed actions, that is, actions that have the same number of facts in their pre-and post-conditions, and bounding the size of facts, that is, the number of symbols they contain. On the other hand, the adversaries inside our system have many capabilities of the standard Dolev-Yao intruder, namely, they are able, within their bounded storage capacity, to compose, decompose, overhear, and intercept messages as well as create fresh values. We investigate the complexity of the decision problem of whether or not an adversary is able to discover secret data. We show that this problem is PSPACE-complete when the size of messages is an input bound and when all actions are balanced and can possibly create fresh values. As an application, we turn to security protocol analysis and demonstrate that many protocol anomalies, such as the Lowe anomaly in the Needham-Schroeder public key exchange protocol, can also occur when the intruder is one of the insiders with bounded memory.
doi:10.1007/978-3-642-19751-2_2 fatcat:5m36t6txbrdgxjvvomjtvoob2i

Bounded Memory Protocols and Progressing Collaborative Systems [chapter]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov
2013 Lecture Notes in Computer Science  
It is well-known that the Dolev-Yao adversary is a powerful adversary. Besides acting as the network, intercepting, sending, and composing messages, he can remember as much information as he needs. That is, his memory is unbounded. We recently proposed a weaker Dolev-Yao like adversary, which also acts as the network, but whose memory is bounded. We showed that this Bounded Memory Dolev-Yao adversary, when given enough memory, can carry out many existing protocol anomalies. In particular, the
more » ... own anomalies arise for bounded memory protocols, where there is only a bounded number of concurrent sessions and the honest participants of the protocol cannot generate an unbounded number of facts nor an unbounded number of nonces. This led us to the question of whether it is possible to infer an upper-bound on the memory required by the Dolev-Yao adversary to carry out an anomaly from the memory restrictions of the bounded protocol. This paper answers this question negatively. The second contribution of this paper is the formalization of Progressing Collaborative Systems that may create fresh values, such as nonces. We also prove the NP-completeness of the reachability problem for Progressing Collaborative Systems that may create fresh values.
doi:10.1007/978-3-642-40203-6_18 fatcat:ecgpuo2pqzhrvak4o3pdcrxpmq

Timed Multiset Rewriting and the Verification of Time-Sensitive Distributed Systems [article]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov, Carolyn Talcott
2021 arXiv   pre-print
Time-Sensitive Distributed Systems (TSDS), such as applications using autonomous drones, achieve goals under possible environment interference (, winds). Moreover, goals are often specified using explicit time constraints which must be satisfied by the system perpetually. For example, drones carrying out the surveillance of some area must always have recent pictures, , at most M time units old, of some strategic locations. This paper proposes a Multiset Rewriting language with explicit time for
more » ... specifying and analysing TSDSes. We introduce two properties, realizability (some trace is good) and survivability (where, in addition, all admissible traces are good). A good trace is an infinite trace in which goals are perpetually satisfied. We propose a class of systems called progressive timed systems (PTS), where intuitively only a finite number of actions can be carried out in a bounded time period. We prove that for this class of systems both the realizability and the survivability problems are PSPACE-complete. Furthermore, if we impose a bound on time (as in bounded model-checking), we show that for PTS, realizability becomes NP-complete, while survivability is in the Δ_2^p class of the polynomial hierarchy. Finally, we demonstrate that the rewriting logic system Maude can be used to automate time bounded verification of PTS.
arXiv:1606.07886v2 fatcat:auwop2u7yra63hbnjxqtzesjwi

A Rewriting Framework for Activities Subject to Regulations

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov, Carolyn Talcott, Ranko Perovic, Marc Herbstritt
2012 International Conference on Rewriting Techniques and Applications  
Activities such as clinical investigations or financial processes are subject to regulations to ensure quality of results and avoid negative consequences. Regulations may be imposed by multiple governmental agencies as well as by institutional policies and protocols. Due to the complexity of both regulations and activities there is great potential for violation due to human error, misunderstanding, or even intent. Executable formal models of regulations, protocols, and activities can form the
more » ... undation for automated assistants to aid planning, monitoring, and compliance checking. We propose a model based on multiset rewriting where time is discrete and is specified by timestamps attached to facts. Actions, goal and critical states may be constrained by means of relative time constraints. Moreover, actions may have non-deterministic effects, i.e., they may have different outcomes whenever applied. We demonstrate how specifications in our model can be straightforwardly mapped to the rewriting logic language Maude, and how one can use existing techniques to improve performance. Finally, we also determine the complexity of the plan compliance problem, that is, finding a plan that leads from an initial state to a desired goal state without reaching any undesired critical state. We consider all actions to be balanced, i.e., their pre and post-conditions have the same number of facts. Under this assumption on actions, we show that the plan compliance problem is PSPACE-complete when all actions have only deterministic effects and is EXPTIME-complete when actions may have non-deterministic effects.
doi:10.4230/lipics.rta.2012.305 dblp:conf/rta/KanovichKNSTP12 fatcat:quggkizubbfcjcon2udbxbosyu

Discrete vs. Dense Times in the Analysis of Cyber-Physical Security Protocols [chapter]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov, Carolyn Talcott
2015 Lecture Notes in Computer Science  
Many security protocols rely on the assumptions on the physical properties in which its protocol sessions will be carried out. For instance, Distance Bounding Protocols take into account the round trip time of messages and the transmission velocity to infer an upper bound of the distance between two agents. We classify such security protocols as Cyber-Physical. Time plays a key role in design and analysis of many of these protocols. This paper investigates the foundational differences and the
more » ... pacts on the analysis when using models with discrete time and models with dense time. We show that there are attacks that can be found by models using dense time, but not when using discrete time. We illustrate this with a novel attack that can be carried out on most distance bounding protocols. In this attack, one exploits the execution delay of instructions during one clock cycle to convince a verifier that he is in a location different from his actual position. We propose a Multiset Rewriting model with dense time suitable for specifying cyber-physical security protocols. We introduce Circle-Configurations and show that they can be used to symbolically solve the reachability problem for our model. Finally, we show that for the important class of balanced theories the reachability problem is PSPACE-complete.
doi:10.1007/978-3-662-46666-7_14 fatcat:6pwyw5jtfzfx7menj7w5mxpgiu

A rewriting framework and logic for activities subject to regulations

MAX KANOVICH, TAJANA BAN KIRIGIN, VIVEK NIGAM, ANDRE SCEDROV, CAROLYN TALCOTT, RANKO PEROVIC
2015 Mathematical Structures in Computer Science  
Activities such as clinical investigations (CIs) or financial processes are subject to regulations to ensure quality of results and avoid negative consequences. Regulations may be imposed by multiple governmental agencies as well as by institutional policies and protocols. Due to the complexity of both regulations and activities, there is great potential for violation due to human error, misunderstanding, or even intent. Executable formal models of regulations, protocols and activities can form
more » ... the foundation for automated assistants to aid planning, monitoring and compliance checking. We propose a model based on multiset rewriting where time is discrete and is specified by timestamps attached to facts. Actions, as well as initial, goal and critical states may be constrained by means of relative time constraints. Moreover, actions may have non-deterministic effects, i.e. they may have different outcomes whenever applied. We present a formal semantics of our model based on focused proofs of linear logic with definitions. We also determine the computational complexity of various planning problems. Plan compliance problem, for example, is the problem of finding a plan that leads from an initial state to a desired goal state without reaching any undesired critical state. We consider all actions to be balanced, i.e. their pre- and post-conditions have the same number of facts. Under this assumption on actions, we show that the plan compliance problem is PSPACE-complete when all actions have only deterministic effects and is EXPTIME-complete when actions may have non-deterministic effects. Finally, we show that the restrictions on the form of actions and time constraints taken in the specification of our model are necessary for decidability of the planning problems.
doi:10.1017/s096012951500016x fatcat:xxyfno43erg5xauxhq7fbuonwq

Towards an automated assistant for clinical investigations

Vivek Nigam, Tajana Ban Kirigin, Andre Scedrov, Carolyn Talcott, Max Kanovich, Ranko Perovic
2012 Proceedings of the 2nd ACM SIGHIT symposium on International health informatics - IHI '12  
Before a drug can be made available to the general public, its effectiveness has to be experimentally evaluated. Experiments that involve human subjects are called Clinical Investigations (CIs). Since human subjects are involved, procedures for CIs are elaborated so that data required for validating the drug can be collected while ensuring the safety of subjects. Moreover, CIs are heavily regulated by public agencies, such as the Food and Drug Administration (FDA). Violations of regulations or
more » ... eviations from procedures should be avoided as they may incur heavy penalties and more importantly may compromise the health of subjects. However, CIs are prone to human error, since CIs are carried out by the study team, which might be overloaded with other tasks, such as hospital and/or pharmacy duties, other trials, etc. In order to avoid discrepancies, we propose developing an automated assistant for helping all the parties to correctly carry out CIs as well as to detect and prevent discrepancies as early as possible. This way the proposed automated assistant would minimize error, and therefore increase the safety of the involved subjects. This paper takes the first steps towards that direction. In particular, we propose a model for collaborative systems with explicit time, called Timed Local State Transition Systems (TLSTS), and argue that it can be used for specifying procedures and regulations for CIs, which mention time explicitly. Finally we show how to implement a TLSTS specification using Maude, an existing computational tool based on rewriting.
doi:10.1145/2110363.2110456 dblp:conf/ihi/NigamKSTKP12 fatcat:3qjtkn2jzvdxbhobr4gvn46djq

Corpus-Based Syntactic-Semantic Graph Analysis

Benedikt Perak, Tajana Ban Kirigin
2020 Rasprave: Časopis Instituta za Hrvatski Jezik i Jezikoslovlje  
ban Kirigin: Corpus-based Syntactic-Semantic Graph analysis: Semantic Domains of the Concept Feeling  ...  according to the PageRank distribution table 20 : 20 nodes in the okus, vid, sluh sub-graph ranked according to the PageRank distribution Rasprave 46/2 (2020.) str. 957-996 benedikt Perak, tajana  ... 
doi:10.31724/rihjj.46.2.27 fatcat:nhmp4wsclfb6nfoitij3gs54xm

Time, computational complexity, and probability in the analysis of distance-bounding protocols

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov, Carolyn Talcott
2017 Journal of Computer Security  
Many security protocols rely on the assumptions on the physical properties in which its protocol sessions will be carried out. For instance, Distance Bounding Protocols take into account the round trip time of messages and the transmission velocity to infer an upper bound of the distance between two agents. We classify such security protocols as Cyber-Physical. Time plays a key role in design and analysis of many of these protocols. This paper investigates the foundational differences and the
more » ... pacts on the analysis when using models with discrete time and models with dense time. We show that there are attacks that can be found by models using dense time, but not when using discrete time. We illustrate this with a novel attack that can be carried out on most Distance Bounding Protocols. In this attack, one exploits the execution delay of instructions during one clock cycle to convince a verifier that he is in a location different from his actual position. We additionally present a probabilistic analysis of this novel attack. As a formal model for representing and analyzing Cyber-Physical properties, we propose a Multiset Rewriting model with dense time suitable for specifying cyber-physical security protocols. We introduce Circle-Configurations and show that they can be used to symbolically solve the reachability problem for our model, and show that for the important class of balanced theories the reachability problem is PSPACE-complete. We also show how our model can be implemented using the computational rewriting tool Maude, the machinery that automatically searches for such attacks.
doi:10.3233/jcs-0560 fatcat:yquvrtuxnja4dl5tkt6bt6u43q

On the Complexity of Verification of Time-Sensitive Distributed Systems: Technical Report [article]

Max Kanovich, Tajana Ban Kirigin, Vivek Nigam, Andre Scedrov, Carolyn Talcott
2021 arXiv   pre-print
This paper develops a Multiset Rewriting language with explicit time for the specification and analysis of Time-Sensitive Distributed Systems (TSDS). Goals are often specified using explicit time constraints. A good trace is an infinite trace in which the goals are satisfied perpetually despite possible interference from the environment. In our previous work (FORMATS 2016), we discussed two desirable properties of TSDSes, realizability (there exists a good trace) and survivability (where, in
more » ... ition, all admissible traces are good). Here we consider two additional properties, recoverability (all compliant traces do not reach points-of-no-return) and reliability (the system can always continue functioning using a good trace). Following (FORMATS 2016), we focus on a class of systems called Progressing Timed Systems (PTS), where intuitively only a finite number of actions can be carried out in a bounded time period. We prove that for this class of systems the properties of recoverability and reliability coincide and are PSPACE-complete. Moreover, if we impose a bound on time (as in bounded model-checking), we show that for PTS the reliability property is in the Π_2^p class of the polynomial hierarchy, a subclass of PSPACE. We also show that the bounded survivability is both NP-hard and coNP-hard.
arXiv:2105.03531v4 fatcat:wmab2iwjn5flnjit2sf4waqhny

On Security Analysis of Periodic Systems: Expressiveness and Complexity

Musab Alturki, Tajana Kirigin, Max Kanovich, Vivek Nigam, Andre Scedrov, Carolyn Talcott
2021 Proceedings of the 7th International Conference on Information Systems Security and Privacy   unpublished
Ban Kirigin is supported in part by the Croatian Science Foundation under the project UIP-05-2017-9219.  ...  ACKNOWLEDGMENTS Part of this work was done during the visits to the University of Pennsylvania by Alturki, Ban Kirigin, Kanovich, Nigam, and Talcott, which were partially supported by ONR grant N00014  ... 
doi:10.5220/0010195100430054 fatcat:gzu3z26i7rectciq2l56nzvomq
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