840 research outputs found
Fault tolerant software technology for distributed computing system
Issued as Monthly reports [nos. 1-23], Interim technical report, Technical guide books [nos. 1-2], and Final report, Project no. G-36-64
Janus: Toward Preventing Counterfeits in Supply Chains Utilizing a Multi-Quorum Blockchain
The modern pharmaceutical supply chain lacks transparency and traceability, resulting in alarming rates of counterfeit products entering the market. These illegitimate products cause harm to end users and wreak havoc on the supply chain itself, costing billions of dollars in profit loss. In this paper, in response to the Drug Supply Chain Security Act (DSCSA), we introduce Janus, a novel pharmaceutical track-and-trace system that utilizes blockchain and cloning-resistant hologram tags to prevent counterfeits from entering the pharmaceutical supply chain. We design a multi-quorum consensus protocol that achieves load balancing across the network. We perform a security analysis to show robustness against various threats and attacks. The implementation of Janus proves that the system is fair, scalable, and resilient
A Concurrency Control Algorithm for an Open and Safe Nested Transaction Model
We present a concurrency control algorithm for an open and safe nested transaction model. We use prewrite operations in our model to increase the concurrency. Prewrite operations are modeled as subtransactions in the nested transaction tree. The subtransaction which initiates prewrite subtransactions are modelled as recovery point subtransaction. The recovery point subtransaction can release their locks before its ancestors commit. Thus, our model increases the concurrency in comparison to other nested transaction models. Our model is useful an environment of long-running transactions common in object oriented databases, computer aided design and in the software development proces
Analysis of Transaction Management Performance
There is currently much interest in incorporating transactions into both operating systems and general purpose programming languages. This paper provides a detailed examination of the design and performance of the“¢ transaction manager of the Camelot system. Camelot is a transaction facility that provides a rich model of transactions intended to support a wide variety of general-purpose applications. The transaction manager's principal function is to execute the protocols that ensure atomicity. The conclusions of this study are: a simple optimization to two-phase commit reduces logging activity of distributed transactions; non-blocking commit is practical for some applications; multithreaded design improves throughput provided that log batching is used; multi-casting reduces the variance of distributed commit protocols in a LAN environment; and the performance of transaction mechanisms such as Camelot depend heavily upon kernel performance
OpenDSU: Digital Sovereignty in PharmaLedger
Distributed ledger networks, chiefly those based on blockchain technologies,
currently are heralding a next generation of computer systems that aims to suit
modern users' demands. Over the recent years, several technologies for
blockchains, off-chaining strategies, as well as decentralised and respectively
self-sovereign identity systems have shot up so fast that standardisation of
the protocols is lagging behind, severely hampering the interoperability of
different approaches. Moreover, most of the currently available solutions for
distributed ledgers focus on either home users or enterprise use case
scenarios, failing to provide integrative solutions addressing the needs of
both.
Herein we introduce the OpenDSU platform that allows to interoperate generic
blockchain technologies, organised - and possibly cascaded in a hierarchical
fashion - in domains. To achieve this flexibility, we seamlessly integrated a
set of well conceived OpenDSU components to orchestrate off-chain data with
granularly resolved and cryptographically secure access levels that are nested
with sovereign identities across the different domains.
Employing our platform to PharmaLedger, an inter-European network for the
standardisation of data handling in the pharmaceutical industry and in
healthcare, we demonstrate that OpenDSU can cope with generic demands of
heterogeneous use cases in both, performance and handling substantially
different business policies. Importantly, whereas available solutions commonly
require a pre-defined and fixed set of components, no such vendor lock-in
restrictions on the blockchain technology or identity system exist in OpenDSU,
making systems built on it flexibly adaptable to new standards evolving in the
future.Comment: 18 pages, 8 figure
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