Code Synchronization Research Articles

Blind Recognition of Frame Synchronization Based on Deep Learning.

In this paper, a deep-learning-based frame synchronization blind recognition algorithm is proposed to improve the detection performance in non-cooperative communication systems. Current methods face challenges in accurately detecting frames under high bit error rates (BER). Our approach begins with flat-top interpolation of binary data and converting it into a series of grayscale images, enabling the application of image processing techniques. By incorporating a scaling factor, we generate RGB images. Based on the matching radius, frame length, and frame synchronization code, RGB images with distinct stripe features are classified as positive samples for each category, while the remaining images are classified as negative samples. Finally, the neural network is trained on these sets to classify test data effectively. Simulation results demonstrate that the proposed algorithm achieves a 100% probability in frame recognition when BER is below 0.2. Even with a BER of 0.25, the recognition probability remains above 90%, which exhibits a performance improvement of over 60% compared with traditional algorithms. This work addresses the shortcomings of existing methods under high error conditions, and the idea of converting sequences into RGB images also provides a reliable solution for frame synchronization in challenging communication environments.

Copyright Protection Based on Hybrid Image Watermark (DCT) with Audio Watermark (EMD)

A digital watermark is a type of security that incorporates data into a signal, making it difficult to erase and showing ownership and validity. An important issue brought about by the growing use of the Internet is illicit copyright infringement and authentication. Previous research has proposed several techniques for this problem but has proven them to be either robust, difficult to detect, or fragile and easy to break. Because of this, in this paper, we use two separate kinds of watermarks—one for image and one for audio—to merge these two purposes into one. The image watermark discrete cosine transform (DCT) is renowned for its robustness. It is embedded in an audio watermarking algorithm based on empirical mode decomposition (EMD), ensuring a safe and fragile embedding process. The audio signal was divided into frames, and each one was decomposed by EMD into intrinsic mode functions (IMFs). The DCT watermark bits and the synchronization codes are embedded into the extrema of the first IMF, a high frequency mode sensitive to any small changes in the audio signal. The experimental outcomes suggest that while using two separate kinds of watermarks may seem like a comprehensive solution, it shows the flexibility of EMD and the limits of the DCT watermark technique in different scenarios.

Interleaved Binary Demodulation Technique for Low-Cost and Fast-Response Visible Light Positioning Using Palindromic Sequences

Recent advancements in visible light positioning (VLP) systems have continuously improved positioning accuracy, extending the application fields in Internet-of-things and factory automation technologies. However, their multiplexing and modulation methods still limit the applicability of VLP systems. Multi-level driving and sensing techniques that use orthogonal frequencies increase the design complexity and are strictly constrained by the bandwidths of the illuminators and sensor devices. Existing binary modulations require additional amendments to the code synchronization. In addition, real-time VLP is fundamentally affected by the distorted signal after orthogonal demultiplexing. Herein, we present a low-cost expansion of VLP that employs binary demodulation in code-division multiplexing. The proposed method utilizes DC-biased binary sequences using the palindromic variant of the Hadamard matrix, which provides perfectly orthogonal sequences while maintaining robustness to signal changes. The proposed demodulation regroups the signal collections of orthogonal sequences in an interleaved manner and determines the source signals via re-modulation. Compared with existing methods, it does not require extra-synchronizing structures and naturally compensates for dynamic sensor signals solely via binary operations. Following its implementation in an FPGA using commercial LEDs and a PIN-PD, we validated that the method achieved 48 dB SNR at a source-to-sensor distance of 10 m. The experiments showed that the proposed method eliminates 45–66% of signal errors and 33–43% of positional displacement during the sensor movements at 800 mm/s. Combined with trilateration, the static positioning error is 0.0158 m on average in 1.31, 0.91, 2.36 m, whereas the standard deviation of the raw position is limited to 0.0016 m.

Research on the construction of intelligent dance teaching ecosystem in universities based on multi-data chain network

Abstract In this paper, the Link16 data chain is used to cycle dance movement teaching resources by time and build the function of different nodes of dance teaching to form a distributed network topology without a central node. The network synchronization method integrates and updates the latest dance teaching resources. The MSK demodulation method is used to regulate the multi-data network information, and the network synchronization sequence is constructed by setting the relevant performance of the synchronization code and the judgment threshold. The motion error optimization algorithm reduces motion errors during high-speed dance. The results show that the variance of each classroom in the dance ecological teaching system is within 0.40, with minor fluctuations. In the evaluation results of the three evaluators, the scores of scientific knowledge were all 5, and the scores of ability, attitude and value were slightly different, but the variance of the total score and each index was under 0.10.

Перевод ТВ-сериалов с английского языка на русский: лингвистический и экстралингвистический аспекты

The paper is devoted to the problem of considering the linguistic and extralinguistic features of the translation of TV series from English into Russian. Its theoretical significance consists in updating the issues of audiovisual translation (hereinafter AVT) and summarizing materials on cultural and pragmatic adaptation of audiovisual texts. The aim of the research is to solve the translation problems associated with overcoming both the linguistic barrier (transmission of realia, humor, reduced vocabulary) and the non-linguistic barrier (synchronization of source and target audiovisual codes) when translating TV series from English into Russian. The scientific novelty of the research lies in finding translation strategies for synchronizing original and translated texts related to phonetic, kinesthetic and time constraints of the audiovisual text. The results of the research obtained during a comparative analysis of the original texts and their translations showed the following: when translating realia, reduced vocabulary and humor, translators resort to functional replacements, explanations or elimination (neutralization of national and cultural specifics), depending on the context in each case. When solving the “over-text” problems of AVT related to the need to synchronize visual, sound and verbal signs of the source and target products, translators proceed primarily from orientation to the target linguoculture and adapt the source text in order to provide an adequate communicative and functional effect on the viewer, for which it is necessary sometimes to shorten the source text or completely change it.

Can Synchronous Code Editing and Awareness Tools Support Remote Tutoring? Effects on Learning and Teaching

One-on-one tutoring is effective for learning computer science since a tutor can work alongside a student and provide tailored feedback on their code. However, translating this type of instruction to a remote setting is challenging. Traditional methods such as screensharing lack key pedagogical functionality and most available tools are designed for collaboration rather than instruction. To identify tools that can support remote tutoring, we conducted an experiment to assess two resources: synchronous editing and awareness tools. In our study, an instructor teaches a learner introductory programming concepts remotely, collaborating through screensharing alone, a shared notebook with real-time collaborative editing, or a shared notebook with additional awareness tools overlaid. To embed the awareness tools, we designed a Chrome extension that enables real-time sharing of gaze and cursor data. Our results show that synchronous editing combined with awareness tools significantly improved learning. The awareness tools also helped tutors better communicate with the student, track their understanding, and establish a sense of presence. As a final contribution, we also assessed the efficacy of gaze-sharing using a webcam eye-tracker. While the accuracy was not as precise as a dedicated sensor, instructors described instances when the gaze was useful for gauging student attention and establishing presence. We discuss implications for remote tutoring in computer science and scaling awareness technology.

SoLiCiT: Synchronous Listen, Code, and Transmit Protocol for Wireless Control Applications

Industrial control applications are deployed in environments characterized by high signal attenuation and severe multipath fading, which is a potential cause for significant packet losses. This is in conflict with achieving low latency and highly reliable wireless communication, a requirement of closed-loop control applications. We propose SoLiCiT, a wireless networking protocol that employs concurrent transmissions with specifically designed erasure coding to meet these demands without the need for retransmissions. Synchronous transmissions help to realize a simple protocol design while using helper nodes to transmit redundancy allows for lost packets to be recovered within fixed and tight latency bounds. We provide a range of coding solutions that can be tailored to the application and also present a case study with a battery storage management application in which battery cells report their status to a central management unit. Using a realistic ray tracing model of the actual battery storage container, we evaluate the radio environment and show the efficacy of SoLiCiT compared to benchmarking schemes, such as a low-power wireless bus.

Locksynth: Deriving Synchronization Code for Concurrent Data Structures with ASP

AbstractWe present Locksynth, a tool that automatically derives synchronization needed for destructive updates to concurrent data structures that involve a constant number of shared heap memory write operations. Locksynth serves as the implementation of our prior work on deriving abstract synchronization code. Designing concurrent data structures involves inferring correct synchronization code starting with a prior understanding of the sequential data structure’s operations. Further, an understanding of shared memory model and the synchronization primitives is also required. The reasoning involved transforming a sequential data structure into its concurrent version can be performed using Answer Set Programming, and we mechanized our approach in previous work. The reasoning involves deduction and abduction that can be succinctly modeled in ASP. We assume that the abstract sequential code of the data structure’s operations is provided, alongside axioms that describe concurrent behavior. This information is used to automatically derive concurrent code for that data structure, such as dictionary operations for linked lists and binary search trees that involve a constant number of destructive update operations. We also are able to infer the correct set of locks (but not code synthesis) for external height-balanced binary search trees that involve left/right tree rotations. Locksynth performs the analyses required to infer correct sets of locks and as a final step, also derives the C++ synchronization code for the synthesized data structures. We also provide a performance analysis of the C++ code synthesized by Locksynth with the hand-crafted versions available from the Synchrobench microbenchmark suite. To the best of our knowledge, our tool is the first to employ ASP as a backend reasoner to perform concurrent data structure synthesis.

GRACED: A Novel Fragile Watermarking for Speech Based on Endpoint Detection

Content authentication and tampering detection of multimedia is a vital application by using digital watermarking. In this paper, we propose a novel fraGile wateRmArking of speeCh based on Endpoint Detection (namely GRACED) to verify the integrity of speech. Firstly, speech signal is framed word by word and each speech frame includes one intact nonsilence word. Subsequently, feature fusion is adopted to generate the fragile watermark which will be embedded into the coefficients of hybrid domain of discrete wavelet transform (DWT) and singular value decomposition (SVD). Finally, the tampering detection is accomplished without using any synchronous code to detect kinds of attacks. Several experiments are executed in order to quantify the performance of the proposed method. Experimental evaluation and comparisons with other schemes demonstrate that the signal-to-noise ratio of the proposed method is high with a favorable imperceptibility. Additionally, the tampering localization of various malicious attacks can be achieved without using synchronous code and the proposed scheme even can determine the attack types.

Retracted] Realization of a Noncontact IC Chip with Embedded Ferroelectric Memory in an Auxiliary Timing Device for Sports Games

The research direction of the new generation of embedded memory can be summarized into two types of embedded nonvolatile memory and embedded volatile memory; the research on online testing of embedded memory started in the past ten years, and there are few research results. This article analyzes the feasibility of the noncontact IC chip in the embedded ferroelectric memory of the sports game auxiliary timing device and is aimed at obtaining an optimized embedded ferroelectric memory by analyzing the relevant data to achieve the update and update of the sports game timing device system. Early sports event timing methods generally use manual timing (stopwatch) or camera shooting timing; this method is inefficient, poor real‐time, huge workload, and prone to errors. This research mainly focuses on the analysis and discussion of the material structure and performance of the embedded ferroelectric memory and the process of noncontact IC chip. This article uses custom welding circuit technology to prepare the best ferroelectric filter in the test part and verifies the influence of temperature on the material; in order to understand the properties of ferroelectric materials at the electronic and atomic level, a first‐order statistical method is obtained. The numerical calculation results of the experiment verify that the evaluation value of the serial port synchronization module as a whole exceeds the pulse synchronization; the network synchronization as a whole exceeds the code synchronization, and the result of the network time service module is the opposite, but as a whole, each module of the noncontact IC chip has strong performance adaptability; in the application of auxiliary timing, the maintainability of noncontact IC chip is quite outstanding, and the maximum value is 7.97; a large number of complex simulation system tasks can be completed by simple and direct tasks.

Intelligent High Payload Audio Watermarking Algorithm Using Colour Image in DWT-SVD Domain

Copyright protection and ownership verification of digital audio tracks have become increasingly important to be enabled by digital watermarking techniques. A novel high payload intelligent audio watermarking scheme with RGB color watermark image is proposed in this paper. The color watermark image is encrypted using Arnold chaotic map and passed through an adaptive scaling filter to scale the image to match the required payload. The encoding process is performed on the scaled encrypted version of the watermark image. A portion of the audio signal is used to embed a synchronization code and the other one is decomposed into short frames. These frames are processed with a two-level discrete wavelet transform (DWT), followed by a singular value decomposition (SVD) process on the approximation coefficients. The encoded watermark is inserted into the diagonal matrix using quantization index modulation (QIM). The inverse process of SVD and DWT is applied to obtain the marked audio signal. Blind extraction of the hidden information from the marked audio signal is performed in the reverse order of the embedding process. Experiments show that security, high payload, transparency and imperceptibility of the algorithm are satisfied. The robustness against several kinds of audio signal processing attacks is shown. Performance evaluation tests with SNR, BER, and FSIM are conducted.

Method for transforming symbolic radar marks of low-noticeable moving objects based on the Talbot effect

In this paper a method to transform radar images of moving aerial objects with scintillating inter-period fluctuations, sometimes resulting to complete signal fading, using the Talbot effect is considered. These transformations are reduced to the establishment of a certain correspondence of the asymptotic equality of perception of visual images, arbitrarily changing in time and space, in the statement about the conditions of simple equality of perception of images of radar marks that have different frequencies of fluctuations. It is shown how this approach can be used to analyze radar data by transforming and smoothing scintillating signal fluctuations, invisible in the presence of interference, into visible symbolic images. First, to detect and recognize the aerial objects from the analysis of relations and functional (semantic) dependencies between attributes, second, to make a decision based on semantic components of symbolic radar images. The possibility of using such transformation to generate pulse-frequency code of fluctuations of the symbolic radar angel-echo images as an important characteristic for their recognition has been experimentally verified. Algorithms for generating symbolic images in asynchronous and synchronous pulse-frequency code are formulated. The symbolic image represented by such a code is considered as an additional feature for recognizing and filtering out natural interferences such as angel-echoes.

On No-Sensing Adversarial Multi-Player Multi-Armed Bandits With Collision Communications

We study the notoriously difficult no-sensing adversarial multi-player multi-armed bandits (MP-MAB) problem from a new perspective. Instead of focusing on the hardness of multiple players, we introduce a new dimension of hardness, called attackability. All adversaries can be categorized based on the attackability and we introduce Adversary-Adaptive Collision-Communication (A2C2), a family of algorithms with forced-collision communication among players. Both attackability-aware and unaware settings are studied, and information-theoretic tools of the Z-channel model and error-correction coding are utilized to address the challenge of implicit communication without collision information in an adversarial environment. For the more challenging attackability-unaware problem, we propose a simple method to estimate the attackability enabled by a novel error-detection repetition code and randomized communication for synchronization. Theoretical analysis proves that asymptotic attackability-dependent sublinear regret can be achieved, with or without knowing the attackability. In particular, the asymptotic regret does not have an exponential dependence on the number of players, revealing a fundamental tradeoff between the two dimensions of hardness in this problem.

Synchronization Strings and Codes for Insertions and Deletions—A Survey

Already in the 1960s, Levenshtein and others studied error-correcting codes that protect against synchronization errors, such as symbol insertions and deletions. However, despite significant efforts, progress on designing such codes has been lagging until recently, particularly compared to the detailed understanding of error-correcting codes for symbol substitution or erasure errors. This paper surveys the recent progress in designing efficient error-correcting codes over finite alphabets that can correct a constant fraction of worst-case insertions and deletions. Most state-of-the-art results for such codes rely on synchronization strings, simple yet powerful pseudo-random objects that have proven to be very effective solutions for coping with synchronization errors in various settings. This survey also includes an overview of what is known about synchronization strings and discusses communication settings related to error-correcting codes in which synchronization strings have been applied.

Single frozen bit polar code synchronisation

A low complexity code synchronisation algorithm is proposed which accurately establishes the code synchronisation state for a polar code decoder using the belief value on a single frozen bit. The a...

Design, Calibration, and Evaluation of a Long-Range 3-D Infrared Positioning System Based on Encoding Techniques

Optical indoor positioning systems have experienced an increasing research interest during the last decade as they can provide 3-D centimeter accuracy using light emitting diode (LED) lighting. In the case of having several LEDs emitting simultaneously and a receiver (e.g., the tag to be localized), these systems face important challenges, such as very high dynamic ranges with low signal-to-noise ratios when the coverage area is increased, multiple access interference (MAI), multipath and near-far effects, calibration issues (misalignments in the receiver and other intrinsic parameters), and so on. Previous work have already shown the feasibility of using LED emitters in combination with quadrature angular diversity aperture (QADA) receivers to implement positioning systems. This work further introduces new design considerations, tested on an experimental setup, to enlarge the emitter–receiver range, thus increasing the total coverage, while dealing with the aforementioned challenges. The system applies encoding techniques to each transmitter to solve the multiple access problem. The performance of two different types of codes has been compared, as well as their influence on the final estimation of the receiver’s position: one based on Kasami sequences and another based on loosely synchronous (LS) codes, derived from complementary sets of sequences. At the receiver, the estimation of the incident point is constrained to angles at which the system can be linearized, and a specific calibration process for this type of sensor has also been defined and applied. The proposal has been finally validated with simulated and experimental results in a large space of $2 \times 2$ m2 (base), with a distance from transmitters to receiver of 3.4 m (height). The experimental tests at distances up to 4 m, carried out after the calibration process, achieve average absolute errors below 10 cm for $X$ and $Y$ axes and around 20 cm for $Z$ axis, and standard deviations below 4 cm for $X$ and $Y$ axes, and around 30 cm for $Z$ axis.

A joint design method of frame synchronization code and LDPC code

Frame synchronization word (FSW) is an important basis in signal synchronization detection. In our work, the joint design of frame synchronization words and error correcting code are proposed which through regularly distributing the frame synchronization words among the information bits to improve the decoding performance of the LDPC. Frame synchronization word should be added to the information sequence corresponding to the position with the check matrix larger column weight which can guarantee that more Frame synchronization words are received by the check node in the decoding iteration. The frame synchronization word is known to the receiver which play an important role in decoding iteration. The results of simulation show that the algorithm makes an obvious improvement in decoding performance when the signal-noise ratio (SNR) is lower than 1 dB.

Improved LPD Characteristics for QS-DS-CDMA Employing Randomization Techniques

Easily and flexibly deployable ad-hoc communication networks emerging in tactical military or even civilian contexts, frequently suffer from poor synchronization due to lack of coordinating infrastructure. In addition to synchronization issues, and especially in military settings, security from the aspect of detectability is also of crucial importance. Imperfect synchronization can be dealt with by making use of Quasi-Synchronous Code Division Multiple Access (QS-CDMA), relying on Loosely Synchronous Codes to maintain orthogonality in the presence of limited time delays. Security, in terms of low probability of detection (LPD) from the standpoint of a malicious adversary, can be improved (reduced detection) by employing randomization techniques that disrupt the inherent structure of the transmitted QS-CDMA signals. This is based on the fact that QS-CDMA signals are Cyclostationary, having (almost) periodic Auto-Correlation functions (ACF) due to eminent signal periodicities (such as spreading code repetition). In this paper, we propose techniques to disturb the ACF and equivalently the Spectral Correlation function, and reduce the Degree of Cyclostationarity (DCS), our LPD measure. Specifically, we investigate randomization via 1) random per symbol time dithering and 2) random selection of spreading sequences, as well as a hybrid approach combining time dithering and code randomization. In all proposed techniques knowledge of the randomization pattern is not required at the legitimate receiver. We derive the Spectral Correlation function of the QS-CDMA signal under the proposed randomization schemes and compare it to simulations. We show through analysis and extensive numerical simulations that the proposed technique can reduce the DCS by almost two orders of magnitude. We also show that enhanced LPD can be achieved using the proposed techniques while sacrificing a part of the reduced time synchronization requirement. We further analyze the implications of the friendly receiver not knowing the randomization pattern and present results on the resulting communication performance.

Performance analysis of incoherent PPM‐OCDMA networks based on optimised modified prime code for multimedia applications

This study presents the design analysis and correlation properties of a new spreading code for the incoherent synchronous pulse position modulation-optical code division multiple access (PPM-OCDMA) networks. The proposed code called optimised modified prime code (OMPC), which refers to the modified prime codes (MPCs) family. Additionally, this new code designed at a higher code length, optimised code weight and good correlation characteristics to enhance communication security and improve the bit error rate (BER) performance. In this study, the proposed code is used as source code for different kinds of multimedia services such as data, voice, and video. Furthermore, the characteristics and correlation properties of the OMPC in comparison with the other MPCs families that utilised in the PPM-OCDMA networks are presented. Moreover, for the PPM-OCDMA networks, the effect of OMPC auto- and cross-correlation properties on the multiple access interference (MAI) was investigated. Consequently, the MAI is considered in the BER analysis and calculations. Finally, the results show that the proposed OMPC is better than the other existing codes with respect to the channel capacity and system performance.

MBOC(6,1,4/33) 신호의 다중경로 영향 완화를 위한 새로운 Strobe 펄스 설계

In this paper, we propose a novel strobe pulse to mitigate the multipath effect of MBOC (6,1,4/33) signal and analyze its performance. By additionally modulating a passband Direct Sequence/Spread Spectrum (DS/SS) signal with a Binary Offset Carrier (BOC) sub-carrier, the signal band can be moved to a desired band, thereby increasing frequency efficiency. In addition, the correlation characteristics of the correct code synchronization point are improved, so that the multipath effect can be reduced to compare with the existing Binary Phase Shift Keying (BPSK) modulated signal. However, the multipath effect is still one of the major performance limitations of the Global Navigation Satellite Systems (GNSSs). A conventional scheme to mitigate multipath effects of GNSS is the Strobe pulse technique. In this paper, we design a new strobe pulse that can effectively mitigate the multipath effects of MBOC (6,1,4/33) signals, and multipath mitigation in the 2-Ray model, a representative channel environment to assess the multipath mitigation performance by computer-based simulation. In order to compare the performance of the proposed new strobe pulse, the W2 pulse scheme with similar implementation complexity is considered. The W2 pulse technique is the one of the Strobe pulse technique for BOC signal. Based on the output of the discriminator in multipath free environment, the pull-in range of the W2 pulse technique is about 0.2 chips, whereas the proposed scheme is about 0.6 chips, which is about 3 times wider. And the false-lock point of the proposed scheme is less than about 20% to compare the W2 scheme. In the same environment, the multipath error envelope of the W2 and the proposed schemes is shown, and both techniques are affected only by the closed-in multipath signal. Among them, the proposed scheme has significantly lower multipath errors due to the closed-in multipath signal compared to the W2 technique, and the maximum value of the proposed scheme based on the running average of the multipath errors is about 32% compared to the W2 scheme.