42,129 research outputs found

    A response by Nathan Wittock to Göde Both's Accomplishing Autonomous Driving: An Unfinished Description

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    A response by Nathan Wittock to Dara Ivanova's Losing and Finding: On the Curious Life of Ethnographic Object

    Fair Exchange in Strand Spaces

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    Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach

    State of the Art in Fair ML: From Moral Philosophy and Legislation to Fair Classifiers

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    Machine learning is becoming an ever present part in our lives as many decisions, e.g. to lend a credit, are no longer made by humans but by machine learning algorithms. However those decisions are often unfair and discriminating individuals belonging to protected groups based on race or gender. With the recent General Data Protection Regulation (GDPR) coming into effect, new awareness has been raised for such issues and with computer scientists having such a large impact on peoples lives it is necessary that actions are taken to discover and prevent discrimination. This work aims to give an introduction into discrimination, legislative foundations to counter it and strategies to detect and prevent machine learning algorithms from showing such behavior

    Population status and habitat preferences of critically endangered Dipterocarpus littoralis in West Nusakambangan, Indonesia

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    The conservation of the endemic tree species Dipterocarpus littoralis (Bl.) Kurz. is hampered by the paucity of information on its population biology and ecology. Consequently, a targeted survey was carried out in the West Nusakambangan Nature Reserve to assess its population size and structure as well as habitat preferences. In total, 676 individuals of D. littoralis were located at 52 locations, with an extent of occurrence of 3.66 km2 and an area of occupancy of 1.71 km2. The population had an inverse-J-shaped distribution of diameter at breast height (DBH), with 63% of individuals in the 0-5 cm class and another 21% in the 5-10 cm class; only 11 (1.6%) mature individuals (DBH≥30) were found. D. littoralis was associated with steep, low, southwest-facing sites and sites that had high litter cover and thickness. Illegal logging and fuel-wood chopping were the main threats to D. littoralis and its habitat. In addition, an invasive shrub, Langkap (Arenga obtusifolia, Arecaceae), was a potential competitor with the seedlings throughout the reserve. In view of its endemism, narrow range and localized distribution, small population, environmental preferences, and the severe threats from anthropogenic activities and invasive species, D. littoralis appears to more than justify its conservation status of Critically Endangered

    The natural distribution and ecology of Blandfordia cunninghamii (Blandfordiaceae)

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    A survey covering almost all known sites and most areas of potential habitat of the rare plant Blandfordia cunninghamii (family Blandfordiaceae) in 2004 recorded over 4000 plants from 27 locations, with 80% of the plants in the upper Blue Mountains west of Sydney (lat 33° 40' S, long 150° 20' E), and the remainder as a disjunct occurrence on Mount Kembla in the Illawarra. Habitat requirements of Blandfordia cunninghamii were found to be southern aspect (SE to SW), a slope of > 30°, high rainfall (>1200 mm a year), good drainage, partial canopy cover (30-50%), and acid clayey sands with a pH of 4.5-5, at an altitude between 500 and 950 m. Using International Union for Conservation of Nature (IUCN) parameters, we consider that the number of plants (less than 10 000), their Extent of Occurrence (940 square km), Area of Occupancy (80 km2) are below the threshold for Vulnerable. There is observed decline in habitat and numbers and we conclude that there may be less than 10 locations (under IUCN definitions). This would mean that the species could be considered Vulnerable under IUCN Criteria
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