Regular Codes Research Articles

Computational toolbox for scattering of focused light from flattened or elongated particles using spheroidal wavefunctions

T-matrix methods, with incident and scattered fields described as sums of multipolar fields, are attractive computational methods for many scattering problems due to their versatility, accuracy, and computational efficiency, especially for repeated calculations. However, numerical difficulties often hamper their use for non-spherical particles with large aspect ratios. Further, even if far-field scattering can be accurately calculated, it can be impossible to accurately calculate near-fields. The use of spheroidal wavefunctions, instead of the commonly-used spherical wavefunctions, can be a useful solution for these problems. However, the mathematical complexity of spheroidal wavefunctions, and the challenging task of accurate numerical calculation of them, are significant barriers to their use. We have developed a computational package of MATLAB routines for performing electromagnetic scattering calculations using spheroidal wavefunctions. These allow the determination of light scattering by non-spherical particles with high aspect ratios that would be inaccessible for double precision calculation using spherical wavefunctions. We demonstrate that our codes can be successfully used for cylinders of aspect ratios from 1/10 and 10, and for metal nanoparticles. We include routines for interoperability with regular T-matrix codes and packages such as our optical tweezers toolbox.

On extended 1-perfect bitrades

Extended 1-perfect codes in the Hamming scheme H(n,q) can be equivalently defined as codes that turn to 1-perfect codes after puncturing in any coordinate, as completely regular codes with certain intersection array, as uniformly packed codes with certain weight coefficients, as diameter perfect codes with respect to a certain anticode, as distance-4 codes with certain dual distances. We define extended 1-perfect bitrades in H(n,q) in five different manners, corresponding to the different definitions of extended 1-perfect codes, and prove the equivalence of these definitions of extended 1-perfect bitrades. For q=2m, we prove that such bitrades exist if and only if n=lq+2. For any q, we prove the nonexistence of extended 1-perfect bitrades if n is odd.

Uttar Pradesh Police: Reforms and Employment Status

An essential part of the state's legal system is the police force. Most people associate the word "police" with state personnel whose duty it is to maintain order, especially when it comes to the ordinary application of the penal code.More than just keeping the peace and catching criminals, today's police officers also help with traffic laws enforcement, crowd control at events like rallies and fairs, supporting emergency services like the fire department and flood rescue teams, and mediating small disputes between members of the public. An essential component of the state's justice system is the police. The word "police" mostly refers to state employees whose job it is to uphold law and order, particularly through the execution of the regular criminal code. In addition to preventing crimes and apprehending offenders, police officers nowadays also assist with other welfare tasks such as assisting with traffic regulations, managing crowds at public events and meetings, supporting fire departments and flood rescue teams, and assisting members of the public in resolving small conflicts.

The classification of orthogonal arrays OA(2048,14,2,7) and some completely regular codes

We describe the classification of orthogonal arrays OA(2048,14,2,7), or, equivalently, completely regular {14;2}-codes in the 14-cube (30848 equivalence classes). In particular, we find that there is exactly one almost-OA(2048,14,2,7+1), up to equivalence. As derived objects, OA(1024,13,2,6) (202917 classes) and completely regular {12,2;2,12}- and {14,12,2;2,12,14}-codes in the 13- and 14-cubes, respectively, are also classified.

The Relationship between Nurses' Knowledge about Emergencies and Code Blue Activation Decisions

Introduction: Code Blue is a hospital system created to overcome the high death rate due to respiratory arrest and cardiac arrest in hospitals. It involves all hospital components, including medical personnel, communication systems, transportation and facilities, and infrastructure. The initial principle of handling cardiac arrest is how nurses can recognize early signs of emergency so that the decision to activate code blue can be made. Knowledge about emergencies is a basic component that nurses must have in making blue activation code decisions. However, in its application, caring for cardiac arrest sufferers carried out by nurses is often still not appropriate.
 Objective: This study aims to determine the relationship between nurses' knowledge of emergencies and the decision to activate code blue.
 Methods: This research is a quantitative research with an analytical survey method using cross-sectional research. In this study, the non-parametric Spearman rank correlation test was carried out at the. Sampling used total sampling technique and obtained 70 respondents.
 Results: There is a relationship between nurses' knowledge about emergencies and the decision to activate code blue at with a significant value of p= 0,000 (p < α 0.05), r = 0.601.
 Conclusion: There is a relationship between nurses' knowledge about emergencies and the decision to activate code blue. Training resuscitation skills and increasing nurses' knowledge through regular training, workshops, or code blue simulations are recommended, especially for patient care units that rarely activate code blue.

Grid codes vs. multi-scale, multi-field place codes for space.

Recent work on bats flying over long distances has revealed that single hippocampal cells have multiple place fields of different sizes. At the network level, a multi-scale, multi-field place cell code outperforms classical single-scale, single-field place codes, yet the performance boundaries of such a code remain an open question. In particular, it is unknown how general multi-field codes compare to a highly regular grid code, in which cells form distinct modules with different scales. In this work, we address the coding properties of theoretical spatial coding models with rigorous analyses of comprehensive simulations. Starting from a multi-scale, multi-field network, we performed evolutionary optimization. The resulting multi-field networks sometimes retained the multi-scale property at the single-cell level but most often converged to a single scale, with all place fields in a given cell having the same size. We compared the results against a single-scale single-field code and a one-dimensional grid code, focusing on two main characteristics: the performance of the code itself and the dynamics of the network generating it. Our simulation experiments revealed that, under normal conditions, a regular grid code outperforms all other codes with respect to decoding accuracy, achieving a given precision with fewer neurons and fields. In contrast, multi-field codes are more robust against noise and lesions, such as random drop-out of neurons, given that the significantly higher number of fields provides redundancy. Contrary to our expectations, the network dynamics of all models, from the original multi-scale models before optimization to the multi-field models that resulted from optimization, did not maintain activity bumps at their original locations when a position-specific external input was removed. Optimized multi-field codes appear to strike a compromise between a place code and a grid code that reflects a trade-off between accurate positional encoding and robustness. Surprisingly, the recurrent neural network models we implemented and optimized for either multi- or single-scale, multi-field codes did not intrinsically produce a persistent "memory" of attractor states. These models, therefore, were not continuous attractor networks.

Tanner (3, 23)-Regular QC-LDPC Codes: Cycle Structure and Girth Distribution

Tanner (3, 23)-Regular QC-LDPC Codes: Cycle Structure and Girth Distribution

Automating Robotic Micro-Assembly of Fluidic Chips and Single Fiber Compression Tests Based-on Θ Visual Measurement With High-Precision Fiducial Markers

At small scales, automating robotic tasks such as assembly, force/displacement characterization, positioning, etc., appear to be particularly limited. This is due to the lack of sufficiently performing and easy-to-implement multi-degrees-of-freedom measurement systems able to measure the relative pose between micro-parts. In order to address this issue, a measurement method based on High-Precision fiducial markers (named HP code) is proposed. This measurement method combines a periodic pattern (providing high resolution by phase-based computation) with more regular QR codes (bringing versatile implementations and a quick detection). The design and method to efficiently locate these HP codes are presented in this paper. Experimental investigations demonstrate ultra-high resolution: <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2$</tex-math> </inline-formula> nm and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5$</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\upmu$</tex-math> </inline-formula> rad along <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X,Y$</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Theta$</tex-math> </inline-formula> respectively (i.e. one thousandth of a pixel typically). The method is designed to be scalable as well as self-calibrated and to provide high robustness and high versatility. Two typical challenging applications in the field of microrobotics are automated to demonstrate these disruptive performances and the easy-to-implement capability of the method: (1) the automated assembly of two micro-fluidic chips through visual servoing with an achieved positioning accuracy below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50$</tex-math> </inline-formula> nm, and (2) the automated micromechanical characterization of single fibers achieved by the integration of HP codes into a compliant structure enabling simultaneous micro-force and displacement sensing capabilities. These achievements highlight the versatility of the method and open the door to the rapid automation of high-quality robotic tasks at the micro scale. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The motivation for this work/study is based on the fact that many application areas are extensively orienting towards microrobotic systems to perform precise tasks with versatility. However, at the micro scale, many disturbances such as the effects of climate change strongly affect this precision. This problem is amplified by the fact that sensors cannot be easily integrated, either by lack of space or by the lack of measurement systems available. Vision-based approaches are widespread at this scale and appear very promising to measure the relative pose between micro-parts. Nevertheless, existing vision-based approaches like digital image correlation are both scale and texture dependent. Due to the lack of space, they are also difficult to use in practice at small scales for high resolution measurement. The main contribution of this paper lies in the capability to achieve ultra-high resolution measurements. For that, a structure based on High-Precision fiducial markers (named HP codes) is proposed and requires few and simple settings while achieving very high resolution both in position and orientation, typically down to one thousandth of a pixel and a few micro radians, respectively. It provides an off-the-shelf solution, versatile, easy to implement and achieves high resolution measurements in the plane (XY <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Theta$</tex-math> </inline-formula> ). HP codes are applicable to a wide range of applications such as tracking of a component/part of a mobile or deformable system, visual servoing of microrobots, positioning of samples, assembly of components or even mechanical characterization. A free distribution of the library is available online at https://projects.femto-st.fr/ vernier/.

On the Classification of Completely Regular Codes with Covering Radius Two and Antipodal Duals

We classify all linear completely regular codes which have covering radiusρ=2and whose dual are antipodal. For this, we firstly show several properties of such dual codes, which are two-weight codes with weightsdandn.

Autovesk: Automatic Vectorized Code Generation from Unstructured Static Kernels Using Graph Transformations

Leveraging the SIMD capability of modern CPU architectures is mandatory to take full advantage of their increased performance. To exploit this capability, binary executables must be vectorized, either manually by developers or automatically by a tool. For this reason, the compilation research community has developed several strategies for transforming scalar code into a vectorized implementation. However, most existing automatic vectorization techniques in modern compilers are designed for regular codes, leaving irregular applications with non-contiguous data access patterns at a disadvantage. In this article, we present a new tool, Autovesk, that automatically generates vectorized code from scalar code, specifically targeting irregular data access patterns. We describe how our method transforms a graph of scalar instructions into a vectorized one, using different heuristics to reduce the number or cost of instructions. Finally, we demonstrate the effectiveness of our approach on various computational kernels using Intel AVX-512 and ARM SVE. We compare the speedups of Autovesk vectorized code over GCC, Clang LLVM, and Intel automatic vectorization optimizations. We achieve competitive results on linear kernels and up to 11× speedups on irregular kernels.

On new infinite families of completely regular and completely transitive codes

In two previous papers we constructed new families of completely regular codes by concatenation methods. Here we determine cases in which the new codes are completely transitive. For these cases we also find the automorphism groups of such codes. For the remaining cases, we show that the codes are not completely transitive assuming an upper bound on the order of the monomial automorphism groups, according to computational results.

What Constitutes the Deployment and Runtime Configuration System? An Empirical Study on OpenStack Projects

Modern software systems are designed to be deployed in different configured environments (e.g., permissions, virtual resources, network connections) and adapted at runtime to different situations (e.g., memory limits, enabling/disabling features, database credentials). Such a configuration during the deployment and runtime of a software system is implemented via a set of configuration files, which together constitute what we refer to as a “configuration system.” Recent research efforts investigated the evolution and maintenance of configuration files. However, they merely focused on a limited part of the configuration system (e.g., specific infrastructure configuration files or Dockerfiles), and their results do not generalize to the whole configuration system. To cope with such a limitation, we aim to better capture and understand what files constitute a configuration system. To do so, we leverage an open card sort technique to qualitatively study 1,756 configuration files from OpenStack, a large and widely studied open source software ecosystem. Our investigation reveals the existence of nine types of configuration files, which cover the creation of the infrastructure on top of which OpenStack will be deployed, along with other types of configuration files used to customize OpenStack after its deployment. These configuration files are interconnected while being used at different deployment stages. For instance, we observe specific configuration files used during the deployment stage to create other configuration files that are used in the runtime stage. We also observe that identifying and classifying these types of files is not straightforward, as five out of the nine types can be written in similar programming languages (e.g., Python and Bash) as regular source code files. We also found that the same file extensions (e.g., Yaml ) can be used for different configuration types, making it difficult to identify and classify configuration files. Thus, we first leverage a machine learning model to identify configuration from non-configuration files, which achieved a median area under the curve (AUC) of 0.91, a median Brier score of 0.12, a median precision of 0.86, and a median recall of 0.83. Thereafter, we leverage a multi-class classification model to classify configuration files based on the nine configuration types. Our multi-class classification model achieved a median weighted AUC of 0.92, a median Brier score of 0.04, a median weighted precision of 0.84, and a median weighted recall of 0.82. Our analysis also shows that with only 100 labeled configuration and non-configuration files, our model reached a median AUC higher than 0.69. Furthermore, our configuration model requires a minimum of 100 configuration files to reach a median weighted AUC higher than 0.75.

Quantum error correction with fractal topological codes

Recently, a class of fractal surface codes (FSCs), has been constructed on fractal lattices with Hausdorff dimension 2+&amp;#x03F5;, which admits a fault-tolerant non-Clifford CCZ gate \cite{zhu2021topological}. We investigate the performance of such FSCs as fault-tolerant quantum memories. We prove that there exist decoding strategies with non-zero thresholds for bit-flip and phase-flip errors in the FSCs with Hausdorff dimension 2+&amp;#x03F5;. For the bit-flip errors, we adapt the sweep decoder, developed for string-like syndromes in the regular 3D surface code, to the FSCs by designing suitable modifications on the boundaries of the holes in the fractal lattice. Our adaptation of the sweep decoder for the FSCs maintains its self-correcting and single-shot nature. For the phase-flip errors, we employ the minimum-weight-perfect-matching (MWPM) decoder for the point-like syndromes. We report a sustainable fault-tolerant threshold (&amp;#x223C;1.7&amp;#x0025;) under phenomenological noise for the sweep decoder and the code capacity threshold (lower bounded by 2.95&amp;#x0025;) for the MWPM decoder for a particular FSC with Hausdorff dimension DH&amp;#x2248;2.966. The latter can be mapped to a lower bound of the critical point of a confinement-Higgs transition on the fractal lattice, which is tunable via the Hausdorff dimension.

Topologies for error-detecting variable-length codes

Given a finite alphabet A and a quasi-metric d over A⁎, we introduce the relation τd,k⊆A⁎×A⁎ such that (x,y)∈τd,k holds whenever d(x,y)≤k. The error detection capability of variable-length codes is expressed in term of conditions over τd,k. With respect to the prefix metric, the factor one, and any quasi-metric associated with some free monoid (anti-)automorphism, we prove that one can decide whether a given regular variable-length code satisfies any of those error detection constraints.

Hack your corpus analysis: How AI can assist corpus linguists deal with messy social media data

This short reflection considers the role of Artificial Intelligence (AI) language models in supporting the work of corpus linguists. The focus is on how AI can be used in the analysis of complex and 'noisy' data commonly found in social media corpora. These datasets are characterized by unconventional language usage, shorthand, hashtags, emoji, and various other forms of creative expression. The discussion will be grounded in the author's ongoing research into emoji which offers an interesting example of the challenges of working with AI in the context of digital discourse analysis. The primary focus will be on how ChatGPT can support the creation and implementation of regular expressions and code for searching, matching, and manipulating text in corpora. The main objective is to guide the reader through the author's reasoning process as a way of reflecting on the integration of AI technology into the academic practice of corpus linguists.

On the Classification of Completely Regular Codes with Covering Radius Two and Antipodal Duals

On the Classification of Completely Regular Codes with Covering Radius Two and Antipodal Duals

Polar-Coded Transmission over 7.8-km Terrestrial Free-Space Optical Links

Free-space optical (FSO) communications can offer high-capacity transmission owing to the properties of the laser beams. However, performance degradation caused by atmospheric turbulence is an urgent issue. Recently, the application of polar codes, which can provide capacity-achieving error-correcting performance with low computational cost for decoding, to FSO communications has been studied. However, long-distance and real-field experiments have not been conducted in these studies. To the best of our knowledge, this study is the first to present the experimental results of polar-coded transmission over 7.8-km FSO links. Using experimental data, we investigated the performance of polar codes over atmospheric channels, including their superiority to regular low-density parity-check codes. We expect that our results will offer a path toward the application of polar codes in high-speed optical communication networks including satellites.

FPGA-based burst-error performance analysis and optimization of regular and irregular SD-LDPC codes for 50G-PON and beyond.

We evaluate the burst-error performance of the regular low-density parity-check (LDPC) code and the irregular LDPC code that has been considered for ITU-T's 50G-PON standard via experimental measurements in FPGA. By using intra codeword interleaving and parity-check matrix rearrangement, we demonstrate that the BER performance can be improved under ∼44-ns-duration burst errors for 50-Gb/s upstream signals.

Free-Ride Coding for Constructions of Coupled LDPC Codes

Free-ride coding, as an approach that admits transmission of a few extra bits over a low-density parity-check (LDPC) coded link without bandwidth expansion, is applied in this paper to construct coupled LDPC codes. Firstly, we present a syndrome channel model and derive the lower and upper bounds on its capacity (referred to as accessible capacity), indicating the feasibility of the reliable transmission of extra bits. Secondly, we present the performance evaluation on both the word error rate (WER) and the bit error rate (BER) for the free-ride codes with simple lower and upper bounds. Then we propose three applications of free-ride coding to construct coupled LDPC codes, including implicit globally-coupled LDPC (GC-LDPC) codes, partial product-LDPC codes, and terminated spatially-coupled LDPC (SC-LDPC) codes, all of which have the figure of merits that they share the same code rates with the basic component LDPC codes. Simulation results show that: 1) the proposed GC-LDPC codes can outperform the component LDPC codes, yielding a coding gain of up to 0.8 dB; 2) the proposed product codes with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(3,6)$ </tex-math></inline-formula> -regular LDPC component codes of length 1024 can lower the WER from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-2}$ </tex-math></inline-formula> down to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-6}$ </tex-math></inline-formula> at the SNR around 2 dB; 3) the proposed terminated SC-LDPC codes can perform as well as the conventional terminated SC-LDPC codes but without any rate loss.

On completely regular codes with minimum eigenvalue in geometric graphs

We prove that any completely regular code with minimum eigenvalue in any geometric graph Γ corresponds to a completely regular code in the clique graph of Γ. Studying the interrelation of these codes, a complete characterization of the completely regular codes in the Johnson graphs J(n,w) with covering radius w−1 and strength 1 is obtained. In particular this result finishes a characterization of the completely regular codes in the Johnson graphs J(n,3). We also classify the completely regular codes of strength 1 in the Johnson graphs J(n,4) with only one case for the eigenvalues left open.