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State (computer science)

About: State (computer science) is a research topic. Over the lifetime, 24436 publications have been published within this topic receiving 225733 citations.


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Journal ArticleDOI
17 Aug 2008
TL;DR: Techniques are presented, inspired by principles used in compiler optimization, that systematically reduce runtime and per-flow state in deep packet inspection.
Abstract: Deep packet inspection is playing an increasingly important role in the design of novel network services. Regular expressions are the language of choice for writing signatures, but standard DFA or NFA representations are unsuitable for high-speed environments, requiring too much memory, too much time, or too much per-flow state. DFAs are fast and can be readily combined, but doing so often leads to state-space explosion. NFAs, while small, require large per-flow state and are slow.We propose a solution that simultaneously addresses all these problems. We start with a first-principles characterization of state-space explosion and give conditions that eliminate it when satisfied. We show how auxiliary variables can be used to transform automata so that they satisfy these conditions, which we codify in a formal model that augments DFAs with auxiliary variables and simple instructions for manipulating them. Building on this model, we present techniques, inspired by principles used in compiler optimization, that systematically reduce runtime and per-flow state. In our experiments, signature sets from Snort and Cisco Systems achieve state-space reductions of over four orders of magnitude, per-flow state reductions of up to a factor of six, and runtimes that approach DFAs.

268 citations

Journal ArticleDOI
TL;DR: A unified approach to the detection of hazards in both combinational and sequential circuits through the use of ternary algebra is concerned, which could be easily implemented in a computer program which would be capable of detecting hazards in circuits containing hundreds of logic blocks.
Abstract: This paper is concerned with a unified approach to the detection of hazards in both combinational and sequential circuits through the use of ternary algebra. First, hazards in a combinational network resulting from the simultaneous changing of two or more inputs are discussed. A technique is described that will detect hazards resulting from both single- and multiple-input changes. The various types of hazards connected with gate-type sequential circuits are also discussed, and a general technique is described that will detect any type of hazard or race condition that could result in an incorrect terminal state. This technique could be easily implemented in a computer program which would be capable of detecting hazards in circuits containing hundreds of logic blocks.

265 citations

Patent
09 May 1990
TL;DR: In this article, a method for determining whether an area under surveillance is in a desired state or an undesired state is presented, which comprises the steps of collecting data in a computer about the area which defines when the area is in the desired states or the undesired states.
Abstract: A security system comprised of a device for monitoring an area under surveillance. The monitoring device produces images of the area. The security system is also comprised of a device for processing the images to determine whether the area is in a desired state or an undesired state. The processing device is trainable to learn the difference between the desired state and the undesired state. In a preferred embodiment, the monitoring device includes a video camera which produces video images of the area and the processing device includes a computer simulating a neural network. A method for determining whether an area under surveillance is in a desired state or an undesired state. The method comprises the steps of collecting data in a computer about the area which defines when the area is in the desired state or the undesired state. Next, training the computer from the collected data to essentially correctly identify when the area is in the desired state or in the undesired state while the area is under surveillance. Next, performing surveillance of the area with a computer such that the computer determines whether the area is in a desired state or the undesired state.

264 citations

Journal ArticleDOI
TL;DR: It is rigorously proved that the probability of failing to detect an incorrect output is exponentially small in a security parameter, while resource overhead remains polynomial in this parameter, which allows entangling gates to be performed between arbitrary pairs of logical qubits with only constant overhead.
Abstract: Blind quantum computing (BQC) allows a client to have a server carry out a quantum computation for them such that the client's input, output, and computation remain private. A desirable property for any BQC protocol is verification, whereby the client can verify with high probability whether the server has followed the instructions of the protocol or if there has been some deviation resulting in a corrupted output state. A verifiable BQC protocol can be viewed as an interactive proof system leading to consequences for complexity theory. We previously proposed [A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual Symposium on Foundations of Computer Science, Atlanta, 2009 (IEEE, Piscataway, 2009), p. 517] a universal and unconditionally secure BQC scheme where the client only needs to be able to prepare single qubits in separable states randomly chosen from a finite set and send them to the server, who has the balance of the required quantum computational resources. In this paper we extend that protocol with additional functionality allowing blind computational basis measurements, which we use to construct another verifiable BQC protocol based on a different class of resource states. We rigorously prove that the probability of failing to detect an incorrect output is exponentially small in a security parameter, while resource overhead remains polynomial in this parameter. This resource state allows entangling gates to be performed between arbitrary pairs of logical qubits with only constant overhead. This is a significant improvement on the original scheme, which required that all computations to be performed must first be put into a nearest-neighbor form, incurring linear overhead in the number of qubits. Such an improvement has important consequences for efficiency and fault-tolerance thresholds.

261 citations

Patent
16 Dec 2016
TL;DR: In this article, a method of conserving energy in a surgical instrument that includes a segmented circuit having a plurality of independently operated circuit segments, a voltage control circuit, an energy source, a memory, and a processor coupled to the memory is presented.
Abstract: A method of conserving energy in a surgical instrument that includes a segmented circuit having a plurality of independently operated circuit segments, a voltage control circuit, an energy source, a memory, and a processor coupled to the memory. The processor is configured to control a state of a circuit segment of the plurality of circuit segments. The state can be an energized state or a deenergized state. The method includes transmitting an energizing signal from the processor to a voltage control circuit, receiving the energizing signal by the voltage control circuit to apply a voltage to a circuit segment of the plurality of circuit segments, applying the voltage to the circuit segment by the voltage control circuit to cause the circuit segment to transition from the deenergized state to the energized state in accordance with an energization sequence that is different from a deenergization sequence.

261 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20251
202426
202314,059
202232,515
2021467
2020690