Code Pairs Research Articles

A concatenated construction of linear complementary pair of codes

A concatenated construction for linear complementary dual codes was given by Carlet et al. using the so-called isometry inner codes. Here, we obtain a concatenated construction to the more general family, linear complementary pair of codes. Moreover, we extend the dual code description of Chen et al. for concatenated codes to duals of generalized concatenated codes. This allows us to use generalized concatenated codes for the construction of linear complementary pair of codes.

Channel Code Using Constrained-Random-Number Generator Revisited

A construction of a channel code by using a source code with decoder side information is introduced. The encoder and decoder pair of any source code can be used for the construction. Constrained-random-number generators, which generate random numbers satisfying a condition specified by a function and its value, are used to construct stochastic encoders and decoders. The result suggests that we can divide the channel coding problem into the problems of channel encoding and source decoding with side information.

HBF-DH: An Enhanced Payload Hybrid Data Hiding Method Based on a Hybrid Strategy and Block Features

This paper proposes an innovative and novel steganography method for an AMBTC compressed image by combining a turtle-shell reference matrix and (7, 4) Hamming code, called hybrid strategy and block feature-based data hiding method (HBF-DH). Firstly, the proposed method compresses an original image by an AMBTC compression technique, and then applies a user predefined threshold pair to classify all compressed blocks into three categories: a smooth block, less complex block, and high complex block. Next, the smooth and less complex blocks are smoothed out with the aim of vacating more space for data hiding. The embedding process is divided into two phases. In the first phase, each quantization level pair of the AMBTC compression codes is used to embed an 8-ary secret digit by using a restrictive turtle-shell reference matrix. The second phase embeds binary secret data into a bitmap according to block characteristics. For smooth blocks, the bitmap is directly replaced as binary secret data by using bit replacement. For a less complex block, the binary secret data is concealed into a bitmap by using our proposed (7, 4) Hamming code based data hiding strategy, which increases the data hiding capacity without significant impact on image quality. The experimental results and analyses prove that the proposed HBF-DH method is superior to other existing AMBTC based data hiding methods in terms of data hiding ability with satisfactory image visual quality.

Relative profiles and extended weight polynomials of almost affine codes

In this paper we study various aspects concerning almost affine codes, a class including, and strictly larger than, that of linear codes. We use the combinatorial tool demi-matroids to show how one can define relative length/dimension and dimension/length profiles of flags (chains) of almost affine codes. In addition we show two specific results. One such result is how one can express the relative length/dimension profiles (also called relative generalized Hamming weights) of a pair of codes in terms of intersection properties between the smallest of these codes and subcodes of the largest code. The other result tells how one can find the extended weight polynomials, expressing the number of codewords of each possible weight, for each code in an infinite hierarchy of extensions of a code over a given alphabet.

Utilization and Validity of the Dental Diagnostic System over Time in Academic and Private Practice.

To fill the void created by insufficient dental terminologies, a multi-institutional workgroup was formed among members of the Consortium for Oral Health Research and Informatics to develop the Dental Diagnostic System (DDS) in 2009. The adoption of dental diagnosis terminologies by providers must be accompanied by rigorous usability and validity assessments to ensure their effectiveness in practice. The primary objective of this study was to describe the utilization and correct use of the DDS over a 4-y period. Electronic health record data were amassed from 2013 to 2016 where diagnostic terms and Current Dental Terminology procedure code pairs were adjudicated by calibrated dentists. With the resultant data, we report on the 4-y utilization and validity of the DDS at 5 dental institutions. Utilization refers to the proportion of instances that diagnoses are documented in a structured format, and validity is defined as the frequency of valid pairs divided by the number of all treatment codes entered. Nearly 10 million procedures ( n = 9,946,975) were documented at the 5 participating institutions between 2013 and 2016. There was a 1.5-fold increase in the number of unique diagnoses documented during the 4-y period. The utilization and validity proportions of the DDS had statistically significant increases from 2013 to 2016 ( P < 0.0001). Academic dental sites were more likely to document diagnoses associated with orthodontic and restorative procedures, while the private dental site was equally likely to document diagnoses associated with all procedures. Overall, the private dental site had significantly higher utilization and validity proportions than the academic dental sites. The results demonstrate an improvement in utilization and validity of the DDS terminology over time. These findings also yield insight into the factors that influence the usability, adoption, and validity of dental terminologies, raising the need for more focused training of dental students. Ensuring that providers use standardized methods for documentation of diagnoses represents a challenge within dentistry. The results of this study can be used by clinicians when evaluating the utility of diagnostic terminologies embedded within the electronic health record.

On Linear Complementary Pair of &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$n$ &lt;/tex-math&gt; &lt;/inline-formula&gt;D Cyclic Codes

The security parameter for a linear complementary pair $(C,D)$ of codes is defined to be the minimum of the minimum distances $d(C)$ and $d(D^\bot)$ . Recently, Carlet et al. showed that if $C$ and $D$ are both cyclic or both 2-D cyclic linear complementary pair of codes, and then, $C$ and $D^\bot$ are equivalent codes. Hence, the security parameter for cyclic and 2-D cyclic linear complementary pair of codes is simply $d(C)$ . We extend this result to $n\text{D}$ cyclic linear complementary pair of codes. The proof of Carlet et al. for the 2-D cyclic case is based on the trace representation of the codes, which is technical and nontrivial to generalize. Our proof for the generalization is based on the zero sets of the ideals corresponding to $n\text{D}$ cyclic codes.

Encoding pairwise Hamming distances of Local Binary Patterns for visual smoke recognition

To achieve scale invariance, existing methods based on multi-scale local binary patterns (LBP) usually concatenate histograms of LBP codes from different scales. Direct concatenation of histograms is very simple and computationally efficient, but it cannot well model the spatial relationship of LBP codes across scales. Aiming at modeling scale-level variations of LBP codes, we measure and encode the relationship between a pair of LBP codes at the same position from two scales. Gaussian filters are applied to generate the scale space of an image, and original LBP codes are extracted on each scale. The Hamming distance between a pair of LBP codes is used to measure variations of LBP codes across scales. To incorporate the scale-level variations of LBPs into codes, we encode the Hamming distance measures in the same way as LBP to generate a novel code, called Pairwise Comparing Local Binary Patterns (PCLBP). To achieve rotation invariance, LBP and PCLBP codes are aligned to the direction with the maximum magnitude of local differences between a center pixel and its neighbors. To improve reliability of the alignments, we also propose a circular Gaussian smoothing method to remove noise in local differences. Finally, we concatenate the histograms of aligned PCLBP and LBP codes to obtain rotation and scale invariant descriptors for smoke classification. Extensive experiments show that our method obviously outperforms existing LBP variants on smoke datasets, and also achieves outstanding performance on other datasets.

Serially Concatenated Low-density Parity Check Codes as Compatible Pairs

Low-density parity checks (LDPC) codes are considered good performance error correction codes. However, decoder complexity increases with increasing code length. In this study, we introduce short-length serially concatenated LDPC codes. The proposed technique uses pairs of compatible LDPC codes that act as outer and inner serially concatenated codes. In this code pair, the inner code takes input that is the same length as the outer LDPC encoder output. This study examined two cases of LDPC codes as compatible pairs with low numbers of iterations and compared bit error rate (BER) performance to a standalone LDPC code with an additive white Gaussian noise channel. We also considered the quadrature phase shift keying QPSK, 16-quadrature amplitude modulation (QAM), and 64-QAM system modulation schemes. Simulation results demonstrate that the proposed system has good BER performance compared to a standalone LDPC code, the results summarized in table and performance curves.

On Linear Complementary Pairs of Codes

We study linear complementary pairs (LCP) of codes $(C, D)$ , where both codes belong to the same algebraic code family. We especially investigate constacyclic and quasi-cyclic LCP of codes. We obtain characterizations for LCP of constacyclic codes and LCP of quasi-cyclic codes. Our result for the constacyclic complementary pairs extends the characterization of linear complementary dual (LCD) cyclic codes given by Yang and Massey. We observe that when $C$ and $D$ are complementary and constacyclic, the codes $C$ and $D^\bot $ are equivalent to each other. Hence, the security parameter $\min (d(C),d(D^\bot))$ for LCP of codes is simply determined by one of the codes in this case. The same holds for a special class of quasi-cyclic codes, namely 2D cyclic codes, but not in general for all quasi-cyclic codes, since we have examples of LCP of double circulant codes not satisfying this conclusion for the security parameter. We present examples of binary LCP of quasi-cyclic codes and obtain several codes with better parameters than known binary LCD codes. Finally, a linear programming bound is obtained for binary LCP of codes and a table of values from this bound is presented in the case $d(C)=d(D^\bot)$ . This extends the linear programming bound for LCD codes.

Building the knowledge base for non-combinable codes according to the Korean Standard Classification of Diseases

The purpose of this study is to develop a knowledge base for non-combinable combinatorial codes to improve the accuracy of disease classification. We defined the rules related to non-combinable codes according to the list of code pairs proposed by the HIRA and the KCD-7 classification rules. A knowledge base was created according to defined rules and verified. To validate the knowledge base, inpatients who were billed for diabetes mellitus in December 2016 were selected as the subject of the study. As a result, the number of combinatorial codes proposed by the HIRA was 1,195, but the number of code pairs generated in the knowledge base was 25,439. Non-combinable codes by confirming with an indication of the HIRA have discovered 1,391 cases. As a result of verification with the code pair of the proposed knowledge base, 100 combinations were found. Non-combinable codes by confirming with an indication of the HIRA have discovered 1,391 cases. As a result of verification with the code pair of the proposed knowledge base, 3,525 combinations were found. It is meaningful that a convenient authoring tool that can automatically catch combinatorial codes was developed to build a knowledge base.

Co‐occurrence matching of local binary patterns for improving visual adaption and its application to smoke recognition

It is challenging to recognize smoke from visual scenes due to large variations of smoke colors, textures and shapes. To improve robustness, we propose a novel feature extraction method based on similarity and dissimilarity matching measures of Local Binary Patterns (LBP). Given two bit‐sequences of an LBP code pair, the similarity and dissimilarity matching measures are defined as the ratios of the 1–1 bitwise matching number to the 0–0 bitwise matching number and the 1–0 number to the 0–1 number, respectively. To capture local code variations, we calculate the measures between LBP codes of a center pixel and its neighbors. Then we compare each measure with its global mean to propose Similarity Matching based Local Binary Patterns (SMLBP) and Dissimilarity Matching based Local Binary Patterns (DMLBP). Since SMLBP and DMLBP extract spatial variations of the 1st order LBP codes, they actually represent the 2nd order variations of pixel values. Furthermore, we adopt different mapping modes and multi‐scale neighborhoods to obtain rotation and scale invariances. Finally, we concatenate the histograms of LBP, SMLBP and DMLBP to generate a feature vector containing 1st and 2nd order information. Experiments show that our method obviously outperforms existing methods.

Joint Optimization of Protograph LDPC Code Pair for Joint Source and Channel Coding

Double protograph low-density parity-check code has been shown to be a good solution for joint source-channel coding. Moreover, the source code and channel code (as one code pair) can be jointly optimized to achieve a good bit error rate (BER) performance. In this paper, first, an optimal design criterion of this code pair based on an extended curve-fitting algorithm is proposed. Second, a joint optimization procedure which searches for both the optimal decoding threshold and the optimal code pair is presented. In addition, for short-to-moderate-length codewords, the finite-length effect cannot be ignored and the procedure has to be modified with a new notion named length-N decoding threshold . The protograph extrinsic information transfer analysis and the BER simulation have shown that our optimized code pairs acquire lower decoding thresholds than conventional code pairs. Moreover, the optimized code pairs with short-to-moderate-length codewords can mitigate the finite-length effect and obtain low length-N decoding thresholds .

An underwater acoustic direct sequence spread spectrum communication system using dual spread spectrum code

With the goal of achieving high stability and reliability to support underwater point-to-point communications and code division multiple access (CDMA) based underwater networks, a direct sequence spread spectrum based underwater acoustic communication system using dual spread spectrum code is proposed. To solve the contradictions between the information data rate and the accuracy of Doppler estimation, channel estimation, and frame synchronization, a data frame structure based on dual spread spectrum code is designed. A long spread spectrum code is used as the training sequence, which can be used for data frame detection and synchronization, Doppler estimation, and channel estimation. A short spread spectrum code is used to modulate the effective information data. A delay cross-correlation algorithm is used for Doppler estimation, and a correlation algorithm is used for channel estimation. For underwater networking, each user is assigned a different pair of spread spectrum codes. Simulation results show that the system has a good anti-multipath, anti-interference, and anti-Doppler performance, the bit error rate can be smaller than 10−6 when the signal-to-noise ratio is larger than −10 dB, the data rate can be as high as 355 bits/s, and the system can be used in the downlink of CDMA based networks.

DETEKSI KEMIRIPAN SOURCE CODE DENGAN METODE FINGERPRINT BASED DISTANCE DAN LEVENSHTEIN DISTANCE

The ease of accessing information makes easier to do plagiarism. Plagiarism not only applied to written essay, but these day copying other people’s program is also considered as plagiarism. This paper will researching an method to automatically calculating the similarity of pair of source code. The method used are fingerprint based distance and Levenshtein Distance. The result will be measured in accuracy, precision, and recall. The result is in some dataset, levenshtein distance is better than fingerprint based distance for detecting plagiarism in student’s code especially beginner in C++.

"Focusing" in Motivational Interviewing: development of a training tool for practitioners.

Motivational Interviewing (MI) is an individual-level approach to behaviour change that has been evaluated in over 600 randomised clinical trials across multiple settings. Increasingly, research efforts focus on how MI works and how it can best be integrated into public health and clinical programmes. As the application of MI expands, a key integration challenge involves specifying the focus of a conversation such that a practitioner might ignite and intensify a patient's internal motivation for change related to that focus. At present, this challenge is poorly conceptualised. We aimed to clarify the construct of "focusing" and to develop a practical tool that can be used to develop and assess practitioner competence. First we reviewed validated MI measures to elucidate current conceptualisations of focusing. Second, we identified practitioner speech acts that led to topic transitions. We then drafted the first version of MIFI. A gold standard rater, together with one expert MI and 3 non-expert MI raters, each used MIFI to coded 20 audio recordings from a feasibility study of MI and breastfeeding maintenance (n=170 observations). Internal consistency and inter-rater reliability analyses were conducted. Published MI measures include 'focusing' as a strategy to agree a target change or to hold attention on that change target. We observed practitioners create or shift focus using 4 skills: questions, listening statements, giving information or meta-statements. Moderate to strong correlations were demonstrated between 4 of 5 global measures on the MIFI. Reliability estimates were good to excellent overall (5 coder ICCs>0.65), fair to excellent for the non-expert coding group (ICCs>0.55) and for the best coding pair (MI expert and non-expert ICCs >0.52). We offer conceptual clarity about focusing in MI and have developed a tool to train practitioners in "focusing" when integrating MI into healthcare and public health interventions.

Relative Generalized Matrix Weights of Matrix Codes for Universal Security on Wire-Tap Networks

Universal security over a network with linear network coding has been intensively studied. However, previous linear codes and code pairs used for this purpose were linear over a larger field than that used on the network, which restricts the possible packet lengths of optimal universal secure codes, does not allow to apply known list-decodable rank-metric codes and requires performing operations over a large field. In this paper, we introduce new parameters (relative generalized matrix weights and relative dimension/rank support profile) for code pairs that are linear over the field used in the network, and show that they measure the universal security performance of these code pairs. For one code and non-square matrices, generalized matrix weights coincide with the existing Delsarte generalized weights, hence we prove the connection between these latter weights and secure network coding, which was left open. As main applications, the proposed new parameters enable us to: 1) obtain optimal universal secure linear codes on noiseless networks for all possible packet lengths, in particular for packet lengths not considered before, 2) obtain the first universal secure list-decodable rank-metric code pairs with polynomial-sized lists, based on a recent construction by Guruswami et al; and 3) obtain new characterizations of security equivalences of linear codes. Finally, we show that our parameters extend relative generalized Hamming weights and relative dimension/length profile, respectively, and relative generalized rank weights and relative dimension/intersection profile, respectively.

Improved Constructions of Nested Code Pairs

Two new constructions of linear code pairs $C_2 \subset C_1$ are given for which the codimension and the relative minimum distances $M_1(C_1,C_2)$, $M_1(C_2^\perp,C_1^\perp)$ are good. By this we mean that for any two out of the three parameters the third parameter of the constructed code pair is large. Such pairs of nested codes are indispensable for the determination of good linear ramp secret sharing schemes [35]. They can also be used to ensure reliable communication over asymmetric quantum channels [47]. The new constructions result from carefully applying the Feng-Rao bounds [18,27] to a family of codes defined from multivariate polynomials and Cartesian product point sets.

Joint Synchronization and Channel Estimation of ACO-OFDM Systems With Simplified Transceiver

To facilitate the development of asymmetrically clipped optical orthogonal frequency division multiplexing systems, a joint synchronization and channel estimation scheme is proposed. The preamble used in the scheme is based on zero correlation code pair and has impulse-like correlation relationship. This property can let the results of synchronization process be the coarsely estimated channel time response, thus simplifies channel frequency response generation. Also, a transceiver with low complexity is proposed. The proposed transceiver needs only half the amount of multiplications compared with conventional transceiver. Simulation results reveal that the proposed scheme achieves better performance both in synchronization and channel estimation than existing schemes.

IR-based technique for linearizing abstract method invocation in plagiarism-suspected source code pair

According to several works, low-level approach is an effective and efficient solution for detecting source code plagiarism. Instead of relying on source code tokens, it compares the executable form of given code; that form only contains semantic-preserving tokens and is resistant to various plagiarism attacks. However, to our knowledge, an issue about statically linearizing abstract method (i.e. replacing each abstract method invocation with its respective invoked method content without considering invocation semantic) has not been handled comprehensively. Such issue, at some extent, will generate inaccurate plagiarism detection result when handling object-oriented source codes. This paper aims to solve such issue locally per plagiarism-suspected pair. It will generate all possible linearization pair alternatives and select the correct one through IR-based similarity. According to our evaluation regarding the reversed number of mismatched token, the number of false positive, and the number of process, proposed technique is more effective and efficient when compared to state-of-the-art and combinatoric technique. In addition, it is also observed that each IR mechanism used in proposed technique has its own exclusive benefit for selecting the correct linearized forms.

Sharper Upper Bounds for Unbalanced Uniquely Decodable Code Pairs

Two sets of 0–1 vectors of fixed length form a uniquely decodeable code pair if their Cartesian product is of the same size as their sumset, where the addition is pointwise over integers. For the size of the sumset of such a pair, van Tilborg has given an upper bound in the general case. Urbanke and Li, and later Ordentlich and Shayevitz, have given better bounds in the unbalanced case, that is, when either of the two sets is sufficiently large. Improvements to the latter bounds are presented.