Attack Trees vs. Fault Trees: Two Sides of the Same Coin from Different Currencies

In this article, we propose decision diagram algorithms to extract minimal cutsets of finite degradation models. Finite degradation models generalize and unify combinatorial models used to support probabilistic risk, reliability and safety analyses (fault trees, attack trees, reliability block diagrams…). They formalize a key idea underlying all risk assessment methods: states of the models represent levels of degradation of the system under study. Although these states cannot be totally ordered, they have a rich algebraic structure that can be exploited to extract minimal cutsets of models, which represent the most relevant scenarios of failure. The notion of minimal cutsets we introduce here generalizes the one defined for fault trees. We show how algorithms used to calculate minimal cutsets can be lifted up to finite degradation models, thanks to a generic decomposition theorem and an extension of the binary decision diagrams technology. We discuss the implementation and performance issues. Finally, we illustrate the interest of the proposed technology by means of the use case stemmed from the oil and gas industry.

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Editorial for the Special Issue on “Fault Trees and Attack Trees: Extensions, Solution Methods, and Applications”

Information ◽

10.3390/info12040175 ◽

2021 ◽

Vol 12 (4) ◽

pp. 175

Author(s):

Daniele Codetta-Raiteri

Keyword(s):

Reliability Analysis ◽

Failure Probability ◽

System Failure ◽

Special Issue ◽

Fault Trees ◽

Qualitative And Quantitative ◽

Minimal Cut Sets ◽

Minimal Cut ◽

Attack Trees ◽

Solution Methods

Fault Trees are well-known models for the reliability analysis of systems, used to compute several kinds of qualitative and quantitative measures, such as minimal cut-sets, system failure probability, sensitivity (importance) indices, etc [...]

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Parametric Analyses of Attack-fault Trees*

Fundamenta Informaticae ◽

10.3233/fi-2021-2066 ◽

2021 ◽

Vol 182 (1) ◽

pp. 69-94

Author(s):

Étienne André ◽

Didier Lime ◽

Mathias Ramparison ◽

Mariëlle Stoelinga

Keyword(s):

Power Plants ◽

Timed Automata ◽

Cyber Physical Systems ◽

Safety Engineering ◽

Fault Trees ◽

Physical Systems ◽

Counter Measures ◽

Attack Trees ◽

Parametric Analyses ◽

Parameter Values

Risk assessment of cyber-physical systems, such as power plants, connected devices and IT-infrastructures has always been challenging: safety (i. e., absence of unintentional failures) and security (i. e., no disruptions due to attackers) are conditions that must be guaranteed. One of the traditional tools used to consider these problems is attack trees, a tree-based formalism inspired by fault trees, a well-known formalism used in safety engineering. In this paper we define and implement the translation of attack-fault trees (AFTs) to a new extension of timed automata, called parametric weighted timed automata. This allows us to parameterize constants such as time and discrete costs in an AFT and then, using the model-checker IMITATOR, to compute the set of parameter values such that a successful attack is possible. Moreover, we add the possibility to define counter-measures. Using the different sets of parameter values computed, different attack and fault scenarios can be deduced depending on the budget, time or computation power of the attacker, providing helpful data to select the most efficient counter-measure.

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Characterization of defects in tabular silver halide grains

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178367 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1046-1047

Author(s):

C. Goessens ◽

D. Schryvers ◽

J. Van Landuyt ◽

A. Verbeeck ◽

R. De Keyzer

Keyword(s):

Radiation Damage ◽

Silver Halide ◽

Chemical Characteristics ◽

X Ray ◽

Free Region ◽

Central Defect ◽

Crystallographic Defects ◽

Physical And Chemical ◽

Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

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The Eleventh Circuit Holds that Agreements in which Pharmaceutical Companies Pay Generic Companies Not to Compete May be Valid

The Journal of Law Medicine & Ethics ◽

10.1017/s107311050000749x ◽

2004 ◽

Vol 32 (1) ◽

pp. 181-184

Author(s):

Amy Garrigues

Keyword(s):

Pharmaceutical Companies ◽

Court Decisions ◽

Patent Holder ◽

Trial Court ◽

Court Of Appeals ◽

The Us ◽

Antitrust Laws ◽

Per Se ◽

Appeals Court ◽

Two Sides

On September 15, 2003, the US. Court of Appeals for the Eleventh Circuit held that agreements between pharmaceutical and generic companies not to compete are not per se unlawful if these agreements do not expand the existing exclusionary right of a patent. The Valley DrugCo.v.Geneva Pharmaceuticals decision emphasizes that the nature of a patent gives the patent holder exclusive rights, and if an agreement merely confirms that exclusivity, then it is not per se unlawful. With this holding, the appeals court reversed the decision of the trial court, which held that agreements under which competitors are paid to stay out of the market are per se violations of the antitrust laws. An examination of the Valley Drugtrial and appeals court decisions sheds light on the two sides of an emerging legal debate concerning the validity of pay-not-to-compete agreements, and more broadly, on the appropriate balance between the seemingly competing interests of patent and antitrust laws.

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The Two Sides of Temporal Orienting

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000018 ◽

2010 ◽

Vol 57 (2) ◽

pp. 142-148 ◽

Cited By ~ 26

Author(s):

Ángel Correa ◽

Paola Cappucci ◽

Anna C. Nobre ◽

Juan Lupiáñez

Keyword(s):

Executive Control ◽

Stroop Effect ◽

Traffic Situation ◽

Target Onset ◽

Stimulus Features ◽

Two Sides ◽

Spatial Stroop Effect ◽

Probable Interval ◽

Spatial Stroop ◽

Temporal Orienting

Would it be helpful to inform a driver about when a conflicting traffic situation is going to occur? We tested whether temporal orienting of attention could enhance executive control to select among conflicting stimuli and responses. Temporal orienting was induced by presenting explicit cues predicting the most probable interval for target onset, which could be short (400 ms) or long (1,300 ms). Executive control was measured both by flanker and Simon tasks involving conflict between incompatible responses and by the spatial Stroop task involving conflict between perceptual stimulus features. The results showed that temporal orienting facilitated the resolution of perceptual conflict by reducing the spatial Stroop effect, whereas it interfered with the resolution of response conflict by increasing flanker and Simon effects. Such opposite effects suggest that temporal orienting of attention modulates executive control through dissociable mechanisms, depending on whether the competition between conflicting representations is located at perceptual or response levels.

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