951 research outputs found
A Logic for Non-Deterministic Parallel Abstract State Machines
We develop a logic which enables reasoning about single steps of
non-deterministic parallel Abstract State Machines (ASMs). Our logic builds
upon the unifying logic introduced by Nanchen and St\"ark for reasoning about
hierarchical (parallel) ASMs. Our main contribution to this regard is the
handling of non-determinism (both bounded and unbounded) within the logical
formalism. Moreover, we do this without sacrificing the completeness of the
logic for statements about single steps of non-deterministic parallel ASMs,
such as invariants of rules, consistency conditions for rules, or step-by-step
equivalence of rules.Comment: arXiv admin note: substantial text overlap with arXiv:1602.0748
Trustee: Full Privacy Preserving Vickrey Auction on top of Ethereum
The wide deployment of tokens for digital assets on top of Ethereum implies
the need for powerful trading platforms. Vickrey auctions have been known to
determine the real market price of items as bidders are motivated to submit
their own monetary valuations without leaking their information to the
competitors. Recent constructions have utilized various cryptographic protocols
such as ZKP and MPC, however, these approaches either are partially
privacy-preserving or require complex computations with several rounds. In this
paper, we overcome these limits by presenting Trustee as a Vickrey auction on
Ethereum which fully preserves bids' privacy at relatively much lower fees.
Trustee consists of three components: a front-end smart contract deployed on
Ethereum, an Intel SGX enclave, and a relay to redirect messages between them.
Initially, the enclave generates an Ethereum account and ECDH key-pair.
Subsequently, the relay publishes the account's address and ECDH public key on
the smart contract. As a prerequisite, bidders are encouraged to verify the
authenticity and security of Trustee by using the SGX remote attestation
service. To participate in the auction, bidders utilize the ECDH public key to
encrypt their bids and submit them to the smart contract. Once the bidding
interval is closed, the relay retrieves the encrypted bids and feeds them to
the enclave that autonomously generates a signed transaction indicating the
auction winner. Finally, the relay submits the transaction to the smart
contract which verifies the transaction's authenticity and the parameters'
consistency before accepting the claimed auction winner. As part of our
contributions, we have made a prototype for Trustee available on Github for the
community to review and inspect it. Additionally, we analyze the security
features of Trustee and report on the transactions' gas cost incurred on
Trustee smart contract.Comment: Presented at Financial Cryptography and Data Security 2019, 3rd
Workshop on Trusted Smart Contract
A study of the mechanism of the Jaffe reaction ; Inverse polarographic determination of creatinine with alkaline picrate and 3,5-dinitrosalicylic acid.
Source: Dissertation Abstracts International, Volume: 62-13, Section: A. Thesis (Ph.D.)--University of Windsor (Canada), 1973
Showing Children the Communicative Nature of Reading
This article explores the effects of the classroom learning environment
Semantics and Proof Theory of the Epsilon Calculus
The epsilon operator is a term-forming operator which replaces quantifiers in
ordinary predicate logic. The application of this undervalued formalism has
been hampered by the absence of well-behaved proof systems on the one hand, and
accessible presentations of its theory on the other. One significant early
result for the original axiomatic proof system for the epsilon-calculus is the
first epsilon theorem, for which a proof is sketched. The system itself is
discussed, also relative to possible semantic interpretations. The problems
facing the development of proof-theoretically well-behaved systems are
outlined.Comment: arXiv admin note: substantial text overlap with arXiv:1411.362
From nonlinear to linearized elasticity via Γ-convergence: the case of multiwell energies satisfying weak coercivity conditions
Linearized elasticity models are derived, via Γ-convergence, from suitably rescaled non- linear energies when the corresponding energy densities have a multiwell structure and satisfy a weak coercivity condition, in the sense that the typical quadratic bound from below is replaced by a weaker p bound, 1 < p < 2, away from the wells. This study is motivated by, and our results are applied to, energies arising in the modeling of nematic elastomers
Logical Dreams
We discuss the past and future of set theory, axiom systems and independence
results. We deal in particular with cardinal arithmetic
Concurrent Computing with Shared Replicated Memory
The behavioural theory of concurrent systems states that any concurrent
system can be captured by a behaviourally equivalent concurrent Abstract State
Machine (cASM). While the theory in general assumes shared locations, it
remains valid, if different agents can only interact via messages, i.e. sharing
is restricted to mailboxes. There may even be a strict separation between
memory managing agents and other agents that can only access the shared memory
by sending query and update requests to the memory agents. This article is
dedicated to an investigation of replicated data that is maintained by a memory
management subsystem, whereas the replication neither appears in the requests
nor in the corresponding answers. We show how the behaviour of a concurrent
system with such a memory management can be specified using concurrent
communicating ASMs. We provide several refinements of a high-level ground model
addressing different replication policies and internal messaging between data
centres. For all these refinements we analyse their effects on the runs such
that decisions concerning the degree of consistency can be consciously made.Comment: 23 page
- …