Search results for "error detection"
showing 10 items of 39 documents
Learning from Errors: Detecting ZigBee Interference in WiFi Networks
2014
In this work we show how to detect ZigBee interference on commodity WiFi cards by monitoring the reception errors, such as synchronization errors, invalid header formats, too long frames, etc., caused by ZigBee transmissions. Indeed, in presence of non-WiFi modulated signals, the occurrence of these types of errors follows statistics that can be easily recognized. Moreover, the duration of the error bursts depends on the transmission interval of the interference source, while the error spacing depends on the receiver implementation. On the basis of these considerations, we propose the adoption of hidden Markov chains for characterizing the behavior of WiFi receivers in presence of controlle…
kmcEx: memory-frugal and retrieval-efficient encoding of counted k-mers.
2018
Abstract Motivation K-mers along with their frequency have served as an elementary building block for error correction, repeat detection, multiple sequence alignment, genome assembly, etc., attracting intensive studies in k-mer counting. However, the output of k-mer counters itself is large; very often, it is too large to fit into main memory, leading to highly narrowed usability. Results We introduce a novel idea of encoding k-mers as well as their frequency, achieving good memory saving and retrieval efficiency. Specifically, we propose a Bloom filter-like data structure to encode counted k-mers by coupled-bit arrays—one for k-mer representation and the other for frequency encoding. Exper…
Node co-activations as a means of error detection : Towards fault-tolerant neural networks
2022
Context: Machine learning has proved an efficient tool, but the systems need tools to mitigate risks during runtime. One approach is fault tolerance: detecting and handling errors before they cause harm. Objective: This paper investigates whether rare co-activations – pairs of usually segregated nodes activating together – are indicative of problems in neural networks (NN). These could be used to detect concept drift and flagging untrustworthy predictions. Method: We trained four NNs. For each, we studied how often each pair of nodes activates together. In a separate test set, we counted how many rare co-activations occurred with each input, and grouped the inputs based on whether its class…
On ARQ feedback intensity of the IEEE 802.16 ARQ mechanism
2008
The IEEE 802.16 standard defines the ARQ mechanism as a part of the MAC layer. The functioning of the ARQ mechanism depends on a number of parameters. The IEEE 802.16 specification defines them but it does not provide concrete values and solutions. We ran simulation scenarios to study how the ARQ feedback intensity impacts the performance of application protocols. The simulation results reveal that a low ARQ feedback intensity results only in a marginal improvement. Though it is possible to optimize the ARQ feedback intensity, it is reasonable to rely upon more frequent ARQ feedback messages as they do not result in a performance degradation. At the same time, ARQ connections, which work on…
Error Detection and Response Adjustment in Youth With Mild Spastic Cerebral Palsy
2013
This study evaluated the brain activation state during error making in youth with mild spastic cerebral palsy and a peer control group while carrying out a stimulus recognition task. The key question was whether patients were detecting their own errors and subsequently improving their performance in a future trial. Findings indicated that error responses of the group with cerebral palsy were associated with weak motor preparation, as indexed by the amplitude of the late contingent negative variation. However, patients were detecting their errors as indexed by the amplitude of the response-locked negativity and thus improved their performance in a future trial. Findings suggest that the con…
On the Trustworthiness of Error-Correcting Codes
2007
The use of error-correcting codes protects data against accidental or intentional errors, but to what extent can a decoded message be trusted? To answer this question, one has to take the role of the receiver. First, the maximum number of errors Lambda acceptable for decoding is fixed. With the weight distribution, the probability of false decoding can be calculated, conditioned on such a Lambda-bounded strategy. This probability is a monotonously increasing function in the channel error probability p and in the maximum number of accepted errors Lambda. Therefore, pure error detection is more trustworthy than error correction. Moreover, for sufficiently small p, codes with the lexicographic…
Systematic Error Correction of a 3D Laser Scanning Measurement Device
2011
International audience; Non-contact measurement techniques using laser scanning have the advantage of fast acquiring large numbers of points. However, compared to their contact-based counterparts, these techniques are known to be less accurate. The work presented in this paper aims at improving the accuracy of these techniques through an error correction procedure based on an experimental process that concerns mechanical parts. The influence of the three parameters defining the relative position and the orientation between the sensor and the surface is studied. The process used to build an experimental global model of error is presented and applied to a typical part composed of planes or sk…
A simple comparative analysis of exact and approximate quantum error correction
2014
We present a comparative analysis of exact and approximate quantum error correction by means of simple unabridged analytical computations. For the sake of clarity, using primitive quantum codes, we study the exact and approximate error correction of the two simplest unital (Pauli errors) and nonunital (non-Pauli errors) noise models, respectively. The similarities and differences between the two scenarios are stressed. In addition, the performances of quantum codes quantified by means of the entanglement fidelity for different recovery schemes are taken into consideration in the approximate case. Finally, the role of self-complementarity in approximate quantum error correction is briefly ad…
An optimal code for patient identifiers.
2004
How to distinguish 1 billion individuals by an identifier consisting of eight characters, allowing a reasonable amount of error detection or even error correction? Our solution of this problem is an optimal code over a 32-character alphabet that detects up to two errors and corrects one error as well as a transposition of two adjacent characters. The corresponding encoding and error checking algorithms are available for free; they are also embedded as components of the pseudonymisation service that is used in the TMF-the German telematics platform for health research networks.
Syntax Error Handling
1990
In the previous chapters we have seen that the various parsers discussed, at least whenever they are deterministic, detect an error in any nonsentence. This means, that on any nonsentence there is a computation ending with an error configuration. For practical parsers, mere error detection is not enough; the parser should also emit a meaningful error message and recover from the error. A recovery means that the error configuration is transformed into a non-error configuration at which normal parsing can be resumed. Moreover, the transformation should be done so that as few input symbols as possible will be discarded. The goal of the error recovery is to maximize the amount of input text tha…