Error suppression via complementary gauge choices in Reed-Muller codes

Concatenation of two quantum error correcting codes with complementary sets of transversal gates can provide a means towards universal fault-tolerant computation. We first show that it is generally preferable to choose the inner code with the higher pseudo-threshold in order to achieve lower logical failure rates. We then explore the threshold properties of a wide range of concatenation schemes. Notably, we demonstrate that the concatenation of complementary sets of Reed-Muller codes can increase the code capacity threshold under depolarizing noise when compared to extensions of previously proposed concatenation models. We also analyze the properties of logical errors under circuit level noise, showing that smaller codes perform better for all sampled physical error rates. Our work provides new insights into the performance of universal concatenated quantum codes for both code capacity and circuit level noise.Comment: 11 pages + 4 appendices, 6 figures. In v2, Fig.1 was added to conform to journal specification

Turbo-Detected Unequal Error Protection Irregular Convolutional Codes Designed for the Wideband Advanced Multirate Speech Codec

Abstract—since the different bits of multimedia information, such as speech and video, have different error sensitivity, efficient unequalprotection channel coding schemes have to be used to ensure that the perceptually more important bits benefit from more powerful protection. Furthermore, in the context of turbo detection the channel codes should also match the characteristics of the channel for the sake of attaining a good convergence performance. In this paper, we address this design dilemma by using irregular convolutional codes (IRCCs) which constitute a family of different-rate subcodes. we benefit from the high design flexibility of IRCCs and hence excellent convergence properties are maintained while having unequal error protection capabilities matched to the requirements of the source. An EXIT chart based design procedure is proposed and used in the context of protecting the different-sensitivity speech bits of the wideband AMR speech codec. As a benefit, the unequalprotection system using IRCCs exhibits an SNR advantage of about 0.4dB over the equal-protection system employing regular convolutional codes, when communicating over a Gaussian channel

Scalable video/image transmission using rate compatible PUM turbo codes

The robust delivery of video over emerging wireless networks poses many challenges due to the heterogeneity of access networks, the variations in streaming devices, and the expected variations in network conditions caused by interference and coexistence. The proposed approach exploits the joint optimization of a wavelet-based scalable video/image coding framework and a forward error correction method based on PUM turbo codes. The scheme minimizes the reconstructed image/video distortion at the decoder subject to a constraint on the overall transmission bitrate budget. The minimization is achieved by exploiting the rate optimization technique and the statistics of the transmission channel

Integration of UAS in the civil airworthiness regulatory system: present and future

The last years are witnessing a number of initiatives worldwide devoted to assess the safety levels of the unmanned aircraft. These initiatives are very heterogeneous; some of them are centred in airworthiness aspects while others focus on operations. From the point of view of a potential UAS manufacturer the actual situation is plenty of uncertainties in relation to the regulations to be applied for certifying the design, manufacturing and maintenance, and from the point of view of the potential operator the situation is analogous with respect to operational procedures. In the present work the emphasis is on the manufacturer’s situation. The objective of this work is to clarify the present civil airworthiness regulatory scene by summarizing all the regulatory efforts up to date and preparing a comparative analysis of them. In this comparison, the manned regulations are included too. The most representative state-of-the-art UAS are analyzed from the point of view of the existing and the future regulatory framework. The main aspects to be considered are related to the airworthiness certification (performances, structural design, etc) for which a quantitative comparison is established in order to clarify how the new regulatory framework, mainly based on the conventional aircraft certification codes, will affect future UAS, compared to the existing regulation

Anticipating climate change: knowledge use in participatory flood management in the river Meuse

Given the latest knowledge on climate change, the Dutch government wants to anticipate the increased risk of flooding. For the river Meuse in The Netherlands, the design discharge is estimated to increase from 3800m3/s to 4600m3/s. With the existing policy of “Room for the River”, this increase is to be accommodated without raising the dikes. At the same time the floodplains are often claimed for other functions, e.g. new housing or industrial estates. In 2001 the Ministry of Transport, Public Works and Water Management started the study “Integrated assessment of the river Meuse (IVM)” with the objectives of making an inventory of the probable physical effects of a design flood, assuming climate change, on the river Meuse in 2050, investigating possible spatial and technical measures to mitigate these effects, and finally combining various measures to create an integral strategy for flood protection, while at the same time increasing spatial quality. This paper presents the results of research into the decision making process that took place in order to achieve these objectives. Special attention was given to the role of scientific and technical knowledge in the decision making process, e.g. by investigating the effect of the quality of input data on acceptance by stakeholders, and the interactive use of a decision support system to visualise hydraulic effects. Conclusions on successes and pitfalls are drawn from observation and interviews with participants. It demonstrates how it is possible to integrate the necessary, technically complex knowledge in a political debate with stakeholders on how to deal with flood risk. Furthermore, the experience indicates in what area improvements could be made

On the Construction and Decoding of Concatenated Polar Codes

A scheme for concatenating the recently invented polar codes with interleaved block codes is considered. By concatenating binary polar codes with interleaved Reed-Solomon codes, we prove that the proposed concatenation scheme captures the capacity-achieving property of polar codes, while having a significantly better error-decay rate. We show that for any $\epsilon > 0$, and total frame length $N$, the parameters of the scheme can be set such that the frame error probability is less than $2^{-N^{1-\epsilon}}$, while the scheme is still capacity achieving. This improves upon 2^{-N^{0.5-\eps}}, the frame error probability of Arikan's polar codes. We also propose decoding algorithms for concatenated polar codes, which significantly improve the error-rate performance at finite block lengths while preserving the low decoding complexity

Electromagnetic Dissociation and Space Radiation

Relativistic nucleus-nucleus reactions occur mainly through the Strong or Electromagnetic (EM) interactions. Transport codes often neglect the latter. This work shows the importance of including EM interactions for space radiation applications.Comment: 11 page

New Modes of Governance in Europe: Policy Making without Legislating? IHS Political Science Series: 2002, No. 81

The article analyzes new modes of governance in Europe. Firstly, different types of new governance, the open coordination method and voluntary accords, and their individual elements are identified. The theoretical discussion about them points out the reasons of their emergence, their mode of operation and the links to the ‘classical’ forms of decision-making. Secondly the simple question of the relative importance of new modes of governance in European policy-making is raised. Looking at the policy measures from the beginning of 2000 until July 2001, the analysis found that only a minority of measures can be considered new modes of governance, defined in the above terms. A third question raised concerns political institutional capacity. Finally the question or instrumental capacity or effectiveness is raised