scholarly journals Repetition code of 15 qubits

2018 ◽  
Vol 97 (5) ◽  
Author(s):  
James R. Wootton ◽  
Daniel Loss
Keyword(s):  
Repetition Code

scholarly journals TYPES OF COMMUNICATION STRATEGIES USED BY YOUNG LEARNERS IN EFL CLASSROOMS

2018 ◽  
Vol 25 (2) ◽  
pp. 53
Author(s):  
Dewi N.L.T. ◽  
Batan I Gede ◽  
Myartawan I P.N.W
Keyword(s):  
Focus Group ◽  
Qualitative Study ◽  
Foreign Language ◽  
Focus Group Discussion ◽  
Communication Strategies ◽  
Group Discussion ◽  
Repetition Code ◽  
Young Learners ◽  
Proficiency Level ◽  
Efl Classrooms

The learner’s proficiency level in communication using English as a foreign language was indicated by their capability to make use of strategies to communicate both in written as well as spoken forms. This qualitative study focused on finding out (i) the types of communication strategies used by the students in EFL classrooms at SMP Negeri 4 Singaraja, and (ii) the students’ reasons towards the use of their communication strategies. The data were obtained from observation and focus group discussion. All data were analysed descriptively. The results of the study indicated that numerous types of strategies were used by the students when communicating in the classroom. They are the use of fillers, self-repetition, code switching, appeal for help, self-repair, asking for confirmation, massage abandonment, omission, approximation, and literal translation. Various types of reasons were expressed by the students toward the use of communication strategies such as thinking time, anxiety, and proficiency level.

WATERMARKING ON COMPRESSED DATA INTEGRATING CONVOLUTION CODING IN INTEGER WAVELETS

2012 ◽  
Vol 10 (06) ◽  
pp. 1250051 ◽  
Author(s):  
SANTI P. MAITY ◽  
CLAUDE DELPHA ◽  
RÉMY BOYER
Keyword(s):  
Channel Coding ◽  
Additive White Gaussian Noise ◽  
Mathematical Structure ◽  
Noise Power ◽  
Repetition Code ◽  
Channel Codes ◽  
Watermark Embedding ◽  
Combined Use ◽  
Integer Wavelet ◽  
Compressed Data

This paper explores the scope of integer wavelets in watermarking on compressed image with the aid of convolution coding as channel coding. Convolution coding is applied on compressed host data, instead of its direct application on watermark signal as used widely for robustness improvement in conventional system. Two-fold advantages, namely flexibility in watermarking through the creation of redundancy on the compressed data as well as protection of watermark information from additive white Gaussian noise (AWGN) attack are achieved. Integer wavelet is used to decompose the encoded compressed data that leads to lossless processing and creation of correlation among the host samples due to its mathematical structure. Watermark information is then embedded using dither modulation (DM)-based quantization index modulation (QIM). The relative gain in imperceptibility and robustness performance are reported for direct watermark embedding on entropy decoded host, using repetition code, convolution code, and finally the combined use of channel codes and integer wavelets. Simulation results show that 6.24 dB (9.50 dB) improvement in document-to-watermark ratio (DWR) at watermark power 12.73 dB (16.81 dB) and 15 dB gain in noise power for watermark decoding at bit error rate (BER) of 10-2 are achieved, respectively over direct watermarking on entropy decoded data.

scholarly journals Machine Learning of Physical Unclonable Functions using Helper Data

2021 ◽  
pp. 1-36
Author(s):  
Emanuele Strieder ◽  
Christoph Frisch ◽  
Michael Pehl
Keyword(s):  
Machine Learning ◽  
Error Correcting Code ◽  
Public Information ◽  
Block Codes ◽  
Mitigation Strategies ◽  
Direct Access ◽  
Physical Unclonable Functions ◽  
Repetition Code ◽  
The Impact ◽  
Helper Data

Physical Unclonable Functions (PUFs) are used in various key-generation schemes and protocols. Such schemes are deemed to be secure even for PUFs with challenge-response behavior, as long as no responses and no reliability information about the PUF are exposed. This work, however, reveals a pitfall in these constructions: When using state-of-the-art helper data algorithms to correct noisy PUF responses, an attacker can exploit the publicly accessible helper data and challenges. We show that with this public information and the knowledge of the underlying error correcting code, an attacker can break the security of the system: The redundancy in the error correcting code reveals machine learnable features and labels. Learning these features and labels results in a predictive model for the dependencies between different challenge-response pairs (CRPs) without direct access to the actual PUF response. We provide results based on simulated data of a k-SUM PUF model and an Arbiter PUF model. We also demonstrate the attack for a k-SUM PUF model generated from real data and discuss the impact on more recent PUF constructions such as the Multiplexer PUF and the Interpose PUF. The analysis reveals that especially the frequently used repetition code is vulnerable: For a SUM-PUF in combination with a repetition code, e.g., already the observation of 800 challenges and helper data bits suffices to reduce the entropy of the key down to one bit. The analysis also shows that even other linear block codes like the BCH, the Reed-Muller, or the Single Parity Check code are affected by the problem. The code-dependent insights we gain from the analysis allow us to suggest mitigation strategies for the identified attack. While the shown vulnerability advances Machine Learning (ML) towards realistic attacks on key-storage systems with PUFs, our analysis also facilitates a better understanding and evaluation of existing approaches and protocols with PUFs. Therefore, it brings the community one step closer to a more complete leakage assessment of PUFs.

Memes as reasonably hostile laments: A discourse analysis of political dissent in Oman

2017 ◽  
Vol 28 (6) ◽  
pp. 573-594 ◽  
Author(s):  
Najma Al Zidjaly
Keyword(s):  
Social Media ◽  
Discourse Analysis ◽  
Political Dissent ◽  
Repetition Code ◽  
Code Choice ◽  
Communicative Strategies ◽  
Saving Face ◽  
Cultural Tools ◽  
Participation Frameworks ◽  
Do So

In this article, I investigate how political dissent is linguistically constructed and mitigated in memes that are circulated nationally on WhatsApp in Oman. I do so by drawing upon insights from relational approaches to face, the theorization of communicative strategies as polysemous and ambiguous, and research pertaining to the Islamic practice of lamenting. The data consist of a representative set of memes collected in the summer and fall of 2015 as part of an ethnographic project on social media and Arab identity. I theorize memes as cultural tools that take the form of ‘reasonably hostile’ lament-narratives, which enable citizens in Oman to engage in democracy while saving face. To create lament-memes that voice dissent while mitigating face-attacks, Omanis draw upon various communicative strategies: They use repetition, code choice, hashtags, and different genres; they juxtapose emojis with text; and they manipulate the production and participation frameworks of texts. Collectively, these strategies, which function via intertextuality, allow the concerns to be aired, but indirectly and playfully. The article demonstrates how political dissent is negotiated and mitigated through memes, the agency of social media users, and the validity of conceptualizing memes as cultural tools.

scholarly journals Quantifying the Performance of Quantum Codes

2011 ◽  
Vol 18 (01) ◽  
pp. 1-31 ◽  
Author(s):  
Carlo Cafaro ◽  
Sonia L'Innocente ◽  
Cosmo Lupo ◽  
Stefano Mancini
Keyword(s):  
Error Correcting Codes ◽  
Quantum Error Correction ◽  
Quantum Codes ◽  
Repetition Code ◽  
Partial Correlations ◽  
Stabilizer Code ◽  
Error Probabilities ◽  
Quantum Error ◽  
Memory Channel ◽  
Noise Models

We study the properties of error correcting codes for noise models in the presence of asymmetries and/or correlations by means of the entanglement fidelity and the code entropy. First, we consider a dephasing Markovian memory channel and characterize the performance of both a repetition code and an error avoiding code ([Formula: see text] and [Formula: see text], respectively) in terms of the entanglement fidelity. We also consider the concatenation of such codes ([Formula: see text]) and show that it is especially advantageous in the regime of partial correlations. Finally, we characterize the effectiveness of the codes [Formula: see text], [Formula: see text] and [Formula: see text] by means of the code entropy and find, in particular, that the effort required for recovering such codes decreases when the error probability decreases and the memory parameter increases. Second, we consider both symmetric and asymmetric depolarizing noisy quantum memory channels and perform quantum error correction via the five-qubit stabilizer code [Formula: see text]. We characterize this code by means of the entanglement fidelity and the code entropy as function of the asymmetric error probabilities and the degree of memory. Specifically, we uncover that while the asymmetry in the depolarizing errors does not affect the entanglement fidelity of the five-qubit code, it becomes a relevant feature when the code entropy is used as a performance quantifier.

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