Formal Availability Analysis using Theorem Proving

Availability analysis is used to assess the possible failures and their restoration process for a given system. This analysis involves the calculation of instantaneous and steady-state availabilities of the individual system components and the usage of this information along with the commonly used availability modeling techniques, such as Availability Block Diagrams (ABD) and Fault Trees (FTs) to determine the system-level availability. Traditionally, availability analyses are conducted using paper-and-pencil methods and simulation tools but they cannot ascertain absolute correctness due to their inaccuracy limitations. As a complementary approach, we propose to use the higher-order-logic theorem prover HOL4 to conduct the availability analysis of safety-critical systems. For this purpose, we present a higher-order-logic formalization of instantaneous and steady-state availability, ABD configurations and generic unavailability FT gates. For illustration purposes, these formalizations are utilized to conduct formal availability analysis of a satellite solar array, which is used as the main source of power for the Dong Fang Hong-3 (DFH-3) satellite.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1505.0264

The Pleistocene Biodiversity of the Zagros Mountains: Carnivores of the Chenar Cave (Kermanshah- Iran)

International audienceOver the past decades, several Pleistocene caves and rock shelters in the Zagros Mountains have been discovered with remarkable evidences of carnivore remains. This paper presents the assemblage of Chenar cave located in Kermanshah (West-Central Zagros), at 1630m asl, on the southern face of the Paraw Mountain. The cave was discovered through an archaeological survey in 2007 by FB and AMB. It included two shafts damaged by looters. The back-dirt sediment was systematically examined indicating 795 animal bones. The nature of the sediment and taphonomical features are undoubtedly an indication of Pleistocene cave. Carnivore remains (43%) consist of fox (Vulpes sp.), striped hyena (Hyaena hyeana), golden jackal (Canis aureus), lynx (Lynx sp.), leopard (Panthera pardus), brown bear (Ursus arctos), cave bear (U.spelaeus / Spelearctos deningeri), caracal (Caracal caracal) and spotted hyena (Crocuta crocuta). The herbivore remains (37%: sheep, goat, boar and cattle) may have been the prey of these carnivores although any anthropogenic traces on the bones have been observed. The Chenar cave was used as a den alternatively for multiple carnivore species, similar to the profile of the Wezmeh cave (SW of the Chenar). Despite the disturbed character of the remains, the presence of spotted and striped hyenas and cave bear adds precious information about the evolution of these species on the Iranian Plateau. Along with Chenar, the past biodiversity of Iran during the Pleistocene is gradually documented by with zooarchaological studies from Wezmeh and Zilou caves in the Zagros and Darband cave in the Alborz Mountains

The Pleistocene Biodiversity of the Zagros Mountains: Carnivores of the Chenar Cave (Kermanshah- Iran)

International audienceOver the past decades, several Pleistocene caves and rock shelters in the Zagros Mountains have been discovered with remarkable evidences of carnivore remains. This paper presents the assemblage of Chenar cave located in Kermanshah (West-Central Zagros), at 1630m asl, on the southern face of the Paraw Mountain. The cave was discovered through an archaeological survey in 2007 by FB and AMB. It included two shafts damaged by looters. The back-dirt sediment was systematically examined indicating 795 animal bones. The nature of the sediment and taphonomical features are undoubtedly an indication of Pleistocene cave. Carnivore remains (43%) consist of fox (Vulpes sp.), striped hyena (Hyaena hyeana), golden jackal (Canis aureus), lynx (Lynx sp.), leopard (Panthera pardus), brown bear (Ursus arctos), cave bear (U.spelaeus / Spelearctos deningeri), caracal (Caracal caracal) and spotted hyena (Crocuta crocuta). The herbivore remains (37%: sheep, goat, boar and cattle) may have been the prey of these carnivores although any anthropogenic traces on the bones have been observed. The Chenar cave was used as a den alternatively for multiple carnivore species, similar to the profile of the Wezmeh cave (SW of the Chenar). Despite the disturbed character of the remains, the presence of spotted and striped hyenas and cave bear adds precious information about the evolution of these species on the Iranian Plateau. Along with Chenar, the past biodiversity of Iran during the Pleistocene is gradually documented by with zooarchaological studies from Wezmeh and Zilou caves in the Zagros and Darband cave in the Alborz Mountains

The Pleistocene Biodiversity of the Zagros Mountains: Carnivores of the Chenar Cave (Kermanshah- Iran)

International audienceOver the past decades, several Pleistocene caves and rock shelters in the Zagros Mountains have been discovered with remarkable evidences of carnivore remains. This paper presents the assemblage of Chenar cave located in Kermanshah (West-Central Zagros), at 1630m asl, on the southern face of the Paraw Mountain. The cave was discovered through an archaeological survey in 2007 by FB and AMB. It included two shafts damaged by looters. The back-dirt sediment was systematically examined indicating 795 animal bones. The nature of the sediment and taphonomical features are undoubtedly an indication of Pleistocene cave. Carnivore remains (43%) consist of fox (Vulpes sp.), striped hyena (Hyaena hyeana), golden jackal (Canis aureus), lynx (Lynx sp.), leopard (Panthera pardus), brown bear (Ursus arctos), cave bear (U.spelaeus / Spelearctos deningeri), caracal (Caracal caracal) and spotted hyena (Crocuta crocuta). The herbivore remains (37%: sheep, goat, boar and cattle) may have been the prey of these carnivores although any anthropogenic traces on the bones have been observed. The Chenar cave was used as a den alternatively for multiple carnivore species, similar to the profile of the Wezmeh cave (SW of the Chenar). Despite the disturbed character of the remains, the presence of spotted and striped hyenas and cave bear adds precious information about the evolution of these species on the Iranian Plateau. Along with Chenar, the past biodiversity of Iran during the Pleistocene is gradually documented by with zooarchaological studies from Wezmeh and Zilou caves in the Zagros and Darband cave in the Alborz Mountains