33,230 research outputs found
Deterministic voting in distributed systems using error-correcting codes
Distributed voting is an important problem in reliable computing. In an N Modular Redundant (NMR) system, the N computational modules execute identical tasks and they need to periodically vote on their current states. In this paper, we propose a deterministic majority voting algorithm for NMR systems. Our voting algorithm uses error-correcting codes to drastically reduce the average case communication complexity. In particular, we show that the efficiency of our voting algorithm can be improved by choosing the parameters of the error-correcting code to match the probability of the computational faults. For example, consider an NMR system with 31 modules, each with a state of m bits, where each module has an independent computational error probability of 10^-3. In, this NMR system, our algorithm can reduce the average case communication complexity to approximately 1.0825 m compared with the communication complexity of 31 m of the naive algorithm in which every module broadcasts its local result to all other modules. We have also implemented the voting algorithm over a network of workstations. The experimental performance results match well the theoretical predictions
Online and Offline BIST in IP-Core Design
This article presents an online and offline built-in self-test architecture implemented as an SRAM intellectual-property core for telecommunication applications. The architecture combines fault-latency reduction, code-based fault detection, and architecture-based fault avoidance to meet reliability constraint
Self-testing and repairing computer Patent
Self testing and repairing computer comprising control and diagnostic unit and rollback points for error correctio
Quantum error correction via robust probe modes
We propose a new scheme for quantum error correction using robust continuous
variable probe modes, rather than fragile ancilla qubits, to detect errors
without destroying data qubits. The use of such probe modes reduces the
required number of expensive qubits in error correction and allows efficient
encoding, error detection and error correction. Moreover, the elimination of
the need for direct qubit interactions significantly simplifies the
construction of quantum circuits. We will illustrate how the approach
implements three existing quantum error correcting codes: the 3-qubit bit-flip
(phase-flip) code, the Shor code, and an erasure code.Comment: 5 pages, 3 figure
Design of a fault tolerant airborne digital computer. Volume 1: Architecture
This volume is concerned with the architecture of a fault tolerant digital computer for an advanced commercial aircraft. All of the computations of the aircraft, including those presently carried out by analogue techniques, are to be carried out in this digital computer. Among the important qualities of the computer are the following: (1) The capacity is to be matched to the aircraft environment. (2) The reliability is to be selectively matched to the criticality and deadline requirements of each of the computations. (3) The system is to be readily expandable. contractible, and (4) The design is to appropriate to post 1975 technology. Three candidate architectures are discussed and assessed in terms of the above qualities. Of the three candidates, a newly conceived architecture, Software Implemented Fault Tolerance (SIFT), provides the best match to the above qualities. In addition SIFT is particularly simple and believable. The other candidates, Bus Checker System (BUCS), also newly conceived in this project, and the Hopkins multiprocessor are potentially more efficient than SIFT in the use of redundancy, but otherwise are not as attractive
Quantum information in the Posner model of quantum cognition
Matthew Fisher recently postulated a mechanism by which quantum phenomena
could influence cognition: Phosphorus nuclear spins may resist decoherence for
long times, especially when in Posner molecules. The spins would serve as
biological qubits. We imagine that Fisher postulates correctly. How adroitly
could biological systems process quantum information (QI)? We establish a
framework for answering. Additionally, we construct applications of biological
qubits to quantum error correction, quantum communication, and quantum
computation. First, we posit how the QI encoded by the spins transforms as
Posner molecules form. The transformation points to a natural computational
basis for qubits in Posner molecules. From the basis, we construct a quantum
code that detects arbitrary single-qubit errors. Each molecule encodes one
qutrit. Shifting from information storage to computation, we define the model
of Posner quantum computation. To illustrate the model's quantum-communication
ability, we show how it can teleport information incoherently: A state's
weights are teleported. Dephasing results from the entangling operation's
simulation of a coarse-grained Bell measurement. Whether Posner quantum
computation is universal remains an open question. However, the model's
operations can efficiently prepare a Posner state usable as a resource in
universal measurement-based quantum computation. The state results from
deforming the Affleck-Kennedy-Lieb-Tasaki (AKLT) state and is a projected
entangled-pair state (PEPS). Finally, we show that entanglement can affect
molecular-binding rates, boosting a binding probability from 33.6% to 100% in
an example. This work opens the door for the QI-theoretic analysis of
biological qubits and Posner molecules.Comment: Published versio
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