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Journal articles on the topic 'Detection of symbol length'

Author: Grafiati

Published: 4 June 2021

Last updated: 2 February 2022

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1

Wu, Yan Jun, Gang Fu, and Gang Cheng. "Pulse Coding Soft FM Telemetry Signal Demodulation." Advanced Materials Research 989-994 (July 2014): 3952–55. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3952.

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The traditional method of demodulation for PCM/FM telemetry demodulation threshold is higher and the computation of the larger problem, research an orthogonal baseband after rotation, Symbol Detection (Multi - Symbol Detection, MSD) technology: the first frequency under the intermediate frequency digital telemetry signals processing, single sign on orthogonal baseband signal correlation matching, and then apply compound spinning technology to meet at the same time for multiple element symbols at the same time Detection, the purpose of the final design step length synchronization method with demodulation smoothly.

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2

Fu, Gang, Yue Feng, and Wen Jian Geng. "Study of Symbol Detection Performance of Two Kinds of Compensation Method." Applied Mechanics and Materials 602-605 (August 2014): 2294–97. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.2294.

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Pulse coding/frequency modulation (PCM/FM) system is a rocket system mainly adopts remote sensing system, and MSD (Multi - Symbol Detection) is to overcome the traditional demodulation methods threshold effect. For multiple symbol detection misjudgment rate is higher in the process of problem, put forward two compensation methods: under the premise of without changing the length of the observation, every time by changing the length of sliding between the ruling and ultimately achieve the purpose of reduce misjudgment. The simulation analysis and test results verified the effectiveness and applicability of two kinds of compensation algorithm.

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Ganapathy, Nagarajan, Diana Baumgärtel, and Thomas Deserno. "Automatic Detection of Atrial Fibrillation in ECG Using Co-Occurrence Patterns of Dynamic Symbol Assignment and Machine Learning." Sensors 21, no. 10 (May 19, 2021): 3542. http://dx.doi.org/10.3390/s21103542.

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Early detection of atrial fibrillation from electrocardiography (ECG) plays a vital role in the timely prevention and diagnosis of cardiovascular diseases. Various algorithms have been proposed; however, they are lacking in considering varied-length signals, morphological transitions, and abnormalities over long-term recordings. We propose dynamic symbolic assignment (DSA) to differentiate a normal sinus rhythm (SR) from paroxysmal atrial fibrillation (PAF). We use ECG signals and their interbeat (RR) intervals from two public databases namely, AF Prediction Challenge Database (AFPDB) and AF Termination Challenge Database (AFTDB). We transform RR intervals into a symbolic representation and compute co-occurrence matrices. The DSA feature is extracted using varied symbol-length V, word-size W, and applied to five machine learning algorithms for classification. We test five hypotheses: (i) DSA captures the dynamics of the series, (ii) DSA is a reliable technique for various databases, (iii) optimal parameters improve DSA’s performance, (iv) DSA is consistent for variable signal lengths, and (v) DSA supports cross-data analysis. Our method captures the transition patterns of the RR intervals. The DSA feature exhibit a statistically significant difference in SR and PAF conditions (p < 0.005). The DSA feature with W=3 and V=3 yield maximum performance. In terms of F-measure (F), rotation forest and ensemble learning classifier are the most accurate for AFPDB (F = 94.6%) and AFTDB (F = 99.8%). Our method is effective for short-length signals and supports cross-data analysis. The DSA is capable of capturing the dynamics of varied-lengths ECG signals. Particularly, the optimal parameters-based DSA feature and ensemble learning could help to detect PAF in long-term ECG signals. Our method maps time series into a symbolic representation and identifies abnormalities in noisy, varied-length, and pathological ECG signals.

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Zhang, Gaoyuan, Haiqiong Li, Congzheng Han, Congyu Shi, Hong Wen, and Dan Wang. "Multiple-Symbol Detection Scheme for IEEE 802.15.4c MPSK Receivers over Slow Rayleigh Fading Channels." Security and Communication Networks 2021 (May 20, 2021): 1–19. http://dx.doi.org/10.1155/2021/6641192.

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Although the full multiple-symbol detection (MSD) for IEEE 802.15.4c multiple phase shift keying (MPSK) receivers gives much better performance than the symbol-by-symbol detection (SBSD), its implementation complexity is extremely heavy. We propose a simple MSD scheme based on two implementation-friendly but powerful strategies. First, we find the best and second-best decisions in each symbol position with the standard SBSD procedure, and the global best decision is frozen. Second, for the remaining symbol positions, only the best and second-best symbol decisions, not all the candidates, are jointly searched by the standard MSD procedure. The simulation results indicate that the packet error rate (PER) performance of the simplified MSD scheme is almost the same as that of the full scheme. In particular, at PER of 1 × 10 − 3 , no more than 0.2 dB performance gap is observed if we just increase the observation window length N to 2. However, the number of decision metrics needed to be calculated is reduced from 256 to 2. Thus, much balance gain between implementation complexity and detection performance is achieved.

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Shi, Congyu, Gaoyuan Zhang, Haiqiong Li, Congzheng Han, Jie Tang, Hong Wen, Longye Wang, and Dan Wang. "Reduced-Complexity Multiple-Symbol Detection of O-QPSK Signals in Smart Metering Utility Networks." Electronics 9, no. 12 (December 2, 2020): 2049. http://dx.doi.org/10.3390/electronics9122049.

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In this work, an implementation-friendly multiple-symbol detection (MSD) scheme is proposed for the IEEE 802.15.4g offset quadrature phase shift keying (O-QPSK) receivers over the slow fading channel. The full MSD scheme presents better detection performance than the symbol-by-symbol detection (SBSD) scheme, yet its complexity increases exponentially as the observation window length increases. We introduce a simplified MSD scheme based on two powerful strategies. We first seek the optimal and suboptimal decisions in each symbol position with the standard SBSD procedure. Then, the aforementioned optimal and suboptimal decisions instead of all candidates are jointly searched with the standard MSD procedure. That is, only the most and second most reliable candidates in each symbol position are selected to participate in the final detection. The simulation results demonstrate that the new MSD scheme can achieve more encouraging energy gain than the SBSD scheme, while the high complexity of full MSD is also effectively reduced. A more legitimate compromise between detection performance and complexity is thus accomplished, which enables smart metering utility networks (SUN) nodes to achieve energy saving and maximum service life.

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Zhu, Dong Xu, Gang Fu, and Qian He. "A Kind of MSD Performance Compensation Method Based on the Strategy of Sliding." Advanced Materials Research 989-994 (July 2014): 2360–63. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.2360.

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The signal noise ratio (SNR) of telemetry signals is low in the environment of reentry telemetry, MSD(Multi-Symbol Detection) technology can effectively improve PCM/FM telemetry signal demodulation performance. In view of the problem that maximum likelihood value is misjudged leaded by the noise in the process of reentry and doppler causing serious distortion of signal phase. A performance compensation method of MSD based on sliding strategy is researched: A MSD operation with N-1 element overlap before each MSD operation, where the each symbol sliding strategy sliding the length of 1 symbol. The simulation and test results verify the effectiveness of the improved algorithm.

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Fu, Gang, Dong Xu Zhu, Ren Long Li, and Li Ping Wang. "Research on Soft Demodulation of Anamorphic PCM/FM Signal under the Condition of Low SNR." Applied Mechanics and Materials 532 (February 2014): 147–51. http://dx.doi.org/10.4028/www.scientific.net/amm.532.147.

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Reentry telemetry channel is a special channel in the process of remote sensing, black barrier and multipath effect will cause the PCM/FM telemetry signal-to-noise ratio and frequency selective fading , even break through the traditional demodulation method of demodulation threshold, led to the bit error rate is greatly increased when aircraft fly through the reentry telemetry channel. Aiming at the problem, a sliding length of 1 more Symbol Detection (Multi - Symbol Detection, MSD) demodulation algorithm is studied: the continuous observations of N element signal and local signal for joint Detection, but each time the MSD sentences a MSD earlier with N - 1 element coincidence. In theory, the algorithm can increase the channel gain about 3 db, the simulation and test results verified the effectiveness of the proposed algorithm.

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8

YU, Yang, Shiro HANDA, Fumihito SASAMORI, and Osamu TAKYU. "Adaptive Iterative Decoding of Finite-Length Differentially Encoded LDPC Coded Systems with Multiple-Symbol Differential Detection." IEICE Transactions on Communications E96.B, no. 3 (2013): 847–58. http://dx.doi.org/10.1587/transcom.e96.b.847.

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Zhang, Gaoyuan, Congzheng Han, Baofeng Ji, Congyu Shi, Ping Xie, and Ling Yang. "A New Multiple-Symbol Differential Detection Strategy for Error-Floor Elimination of IEEE 802.15.4 BPSK Receivers Impaired by Carrier Frequency Offset." Wireless Communications and Mobile Computing 2019 (November 26, 2019): 1–26. http://dx.doi.org/10.1155/2019/5409612.

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In this paper, we pay our attention towards the noncoherent demodulation aspect of binary phase shift keying (BPSK) receivers for IEEE 802.15.4 wireless sensor networks (WSNs), and a carrier frequency offset invariant as well as error-floor free multiple-symbol differential detection (MSDD) strategy is proposed over the flat fading channel. This detector is an alternative to the multiple-symbol detector that has been considered almost exclusively in the past. In this new configuration, the receivers do not perform chip-level precompensation as in conventional scheme but bit-level postcompensation. That is, the bit-level autocorrelation operation is first implemented with the “raw” chip sample, and then the carrier frequency offset effect (CFOE) embedded in the achieved statistic is compensated. Correspondingly, the cumulative error in the detection metric is decreased so much that the pervasive error floor for the conventional MSDD scheme is suppressed. Also, complexity efficient estimators for the MSDD scheme are reinvestigated, analyzed, and summarized. Simulation results demonstrate that this new detection strategy may achieve rather more encouraging gain from differential and spread spectrum coding than the conventional single differential coherent detection (SDCD) scheme. The pervasive error floor is also eliminated as compared with conventional MSDD scheme even if the most simple estimator is configured under large bit observation length. Then, much transmitting energy may be saved for each chip symbol, which is practically desired for transmit-only nodes in WSNs.

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Song, Lijun, Xia Lei, Maozhu Jin, and Zhihan Lv. "Joint Channel Estimation and Signal Detection for the OFDM System Without Cyclic Prefix Over Doubly-Selective Channels." International Journal of Bifurcation and Chaos 25, no. 14 (December 30, 2015): 1540028. http://dx.doi.org/10.1142/s0218127415400283.

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In the high-speed railway wireless communication, a joint channel estimation and signal detection algorithm is proposed for the orthogonal frequency division multiplexing (OFDM) system without cyclic prefix in the doubly-selective fading channels. Our proposed method first combines the basis expansion model (BEM) and the inter symbol interference (ISI) cancellation to overcome the situation that exists with the fast time-varying channel and the normalized maximum multipath channel exceeding the length of the cyclic prefix (CP). At first, the channel estimation and signal detection can be approximated without considering the ISI. Then, the channel parameters and signal detection are updated through ISI cancellation and circular convolution reconstruction from the frequency domain. The simulations show the algorithm can improve the performance of channel estimation and signal detection.

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Khair, Fauza, Fakhriy Hario P, I. Wayan Mustika, and Budi Setiyanto. "Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 3 (June 1, 2016): 1086. http://dx.doi.org/10.11591/ijece.v6i3.9656.

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Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

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Khair, Fauza, Fakhriy Hario P, I. Wayan Mustika, and Budi Setiyanto. "Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 3 (June 1, 2016): 1086. http://dx.doi.org/10.11591/ijece.v6i3.pp1086-1095.

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Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

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Liu, Li, Jin Kuan Wang, Xin Song, and Yin Hua Han. "Improved Stack Algorithm for MIMO Systems." Applied Mechanics and Materials 333-335 (July 2013): 666–69. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.666.

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Multiple input multiple output (MIMO) systems could increase wireless communication system capacity enormously. The best optimal detection algorithm for MIMO systems was maximum likelihood (ML) detection algorithm, which could provide the best bit error rate (BER) performance for MIMO systems. However, the computational complexity of ML detection algorithm grew exponentially with the number of transmit antennas and the order of modulation, which resulted in difficult using for practice. A modified MIMO signal detection algorithm which combined ML detection with stack algorithm was presented in this paper. After performing QR decomposition of the channel matrix, the ML detection with length L was done firstly. The partial accumulated metrics were calculated and sorted, which produced an ordered set secondly. Based on the ordered set, stack algorithm was performed to search for the symbol with the minimum accumulated metrics. The proposed algorithm reduced the probability of look back in stack algorithm.

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14

Schott, Dominik Jan, Andrea Gabbrielli, Wenxin Xiong, Georg Fischer, Fabian Höflinger, Johannes Wendeberg, Christian Schindelhauer, and Stefan Johann Rupitsch. "Asynchronous Chirp Slope Keying for Underwater Acoustic Communication." Sensors 21, no. 9 (May 10, 2021): 3282. http://dx.doi.org/10.3390/s21093282.

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We propose an asynchronous acoustic chirp slope keying to map short bit sequences on single or multiple bands without preamble or error correction coding on the physical layer. We introduce a symbol detection scheme in the demodulator that uses the superposed matched filter results of up and down chirp references to estimate the symbol timing, which removes the requirement of a preamble for symbol synchronization. Details of the implementation are disclosed and discussed, and the performance is verified in a pool measurement on laboratory scale, as well as the simulation for a channel containing Rayleigh fading and Additive White Gaussian Noise. For time-bandwidth products (TB) of 50 in single band mode, a raw data rate of 100 bit/s is simulated to achieve bit error rates (BER) below 0.001 for signal-to-noise ratios above −6 dB. In dual-band mode, for TB of 25 and a data rate of 200 bit/s, the same bit error level was achieved for signal-to-noise ratios above 0 dB. The simulated packet error rates (PER) follow the general behavior of the BER, but with a higher error probability, which increases with the length of bits in each packet.

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Dhawan, Divya, and Neena Gupta. "Performance Analysis of Post Compensated Long Haul High Speed Coherent Optical OFDM System." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 1 (February 1, 2017): 160. http://dx.doi.org/10.11591/ijece.v7i1.pp160-168.

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<p>This paper addresses the performance analysis of OFDM transmission system based on coherent detection over high speed long haul optical links with high spectral efficiency modulation formats such as Quadrature Amplitude Modulation (QAM) as a mapping method prior to the OFDM multicarrier representation. Post compensation is used to compensate for phase noise effects. Coherent detection for signal transmitted at bit rate of 40 Gbps is successfully achieved up to distance of 3200km. Performance is analyzed in terms of Symbol Error Rate and Error Vector Magnitude by varying Optical Signal to Noise Ratio (OSNR) and varying the length of the fiber i.e transmission distance. Transmission performance is also observed through constellation diagrams at different transmission distances and different OSNRs.</p>

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Patra, Jyoti P., and Poonam Singh. "Improved Signal Detection Techniques for QOSTBC System in Fast Fading Channel." Journal of Telecommunications and Information Technology 1 (March 31, 2020): 6–12. http://dx.doi.org/10.26636/jtit.2020.138019.

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Most existing quasi-orthogonal space time Block coding (QO-STBC) schemes have been developed relying on the assumption that the channel is at or remains static during the length of the code word symbol periods to achieve an optimal antenna diversity gain. However, in time-selective fading channels, this assumption does not hold and causes intertransmit-antenna-interferences (ITAI). Therefore, the simple pairwise maximum likelihood decoding scheme is not sufficient to recover original transmitted signals at the receiver side. To avoid the interferences, we have analyzed several signal detection schemes, namely zero forcing (ZF), two-step zero forcing (TS-ZF), minimum mean square error (MMSE), zero forcing - interference cancelation - decision feedback equalizer (ZF-IC-DFE) and minimum mean square error - interference cancelation { decision feedback equalizer (MMSE-IC-DFE). We have proposed two efficient iterative signal detection schemes, namely zero forcing - iterative interference cancelation - zero forcing { decision feedback equalization (ZF-IIC-ZF-DFE) and minimum mean square error - parallel interference cancelation - zero forcing – decision feedback equalization (MMSE-IIC-ZF-DFE). The simulation results show that these two proposed detection schemes significantly outperform all conventional methods for QOSTBC system over time selective channel.

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Sun, Xiaoyong, Shaojing Su, Zhen Zuo, Xiaojun Guo, and Xiaopeng Tan. "Modulation Classification Using Compressed Sensing and Decision Tree–Support Vector Machine in Cognitive Radio System." Sensors 20, no. 5 (March 6, 2020): 1438. http://dx.doi.org/10.3390/s20051438.

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In this paper, a blind modulation classification method based on compressed sensing using a high-order cumulant and cyclic spectrum combined with the decision tree–support vector machine classifier is proposed to solve the problem of low identification accuracy under single-feature parameters and reduce the performance requirements of the sampling system. Through calculating the fourth-order, eighth-order cumulant and cyclic spectrum feature parameters by breaking through the traditional Nyquist sampling law in the compressed sensing framework, six different cognitive radio signals are effectively classified. Moreover, the influences of symbol length and compression ratio on the classification accuracy are simulated and the classification performance is improved, which achieves the purpose of identifying more signals when fewer feature parameters are used. The results indicate that accurate and effective modulation classification can be achieved, which provides the theoretical basis and technical accumulation for the field of optical-fiber signal detection.

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Wang, Litao, Mostafa G. Mehrabi, and Elijah Kannatey-Asibu,. "Hidden Markov Model-based Tool Wear Monitoring in Turning." Journal of Manufacturing Science and Engineering 124, no. 3 (July 11, 2002): 651–58. http://dx.doi.org/10.1115/1.1475320.

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This paper presents a new modeling framework for tool wear monitoring in machining processes using hidden Markov models (HMMs). Feature vectors are extracted from vibration signals measured during turning. A codebook is designed and used for vector quantization to convert the feature vectors into a symbol sequence for the hidden Markov model. A series of experiments are conducted to evaluate the effectiveness of the approach for different lengths of training data and observation sequence. Experimental results show that successful tool state detection rates as high as 97% can be achieved by using this approach.

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J. Santhosh Kumar, B., and Kankanala Pujitha. "Web Application Vulnerability Detection Using Hybrid String Matching Algorithm." International Journal of Engineering & Technology 7, no. 3.6 (July 4, 2018): 106. http://dx.doi.org/10.14419/ijet.v7i3.6.14950.

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Application uses URL as contribution for Web Application Vulnerabilities recognition. if the length of URL is too long then it will consume more time to scan the URL (Ain Zubaidah et.al 2014).Existing system can notice the web pages but not overall web application. This application will test for URL of any length using String matching algorithm. To avoid XSS and CSRF and detect attacks that try to sidestep program upheld arrangements by white list and DOM sandboxing techniques (Elias Athanasopoulos et.al.2012). The web application incorporates a rundown of cryptographic hashes of legitimate (trusted) client side contents. In the event that there is a cryptographic hash for the content in the white list. On the off chance that the hash is discovered the content is viewed as trusted or not trusted. This application makes utilization of SHA-1 for making a message process. The web server stores reliable scripts inside div or span HTML components that are attribute as reliable. DOM sandboxing helps in identifying the script or code. Partitioning Program Symbols into Code and Non-code. This helps to identify any hidden code in trusted tag, which bypass web server. Scanning the website for detecting the injection locations and injecting the mischievous XSS assault vectors in such infusion focuses and check for these assaults in the helpless web application( Shashank Gupta et.al 2015).The proposed application improve the false negative rate.

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FAURE, PHILIPPE, and ANNICK LESNE. "RECURRENCE PLOTS FOR SYMBOLIC SEQUENCES." International Journal of Bifurcation and Chaos 20, no. 06 (June 2010): 1731–49. http://dx.doi.org/10.1142/s0218127410026794.

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This paper introduces an extension of recurrence analysis to symbolic sequences. Heuristic arguments based on Shannon–McMillan–Breiman theorem suggest several relations between the statistical features of "symbolic" recurrence plots and the entropy per unit time of the dynamics; their practical efficiency for experimental sequences of finite length is checked numerically on two paradigmatic models, namely discretized logistic map trajectories and Markov chains, and also on experimental behavioral sequences. Specific advantages of RP analysis are presented, among which is the detection of nonstationary features.

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Mingroni-Netto, Regina C., Rita C. M. Pavanello, Paulo A. Otto, and Angela M. Vianna-Morgante. "Experience with molecular and cytogenetic diagnosis of fragile X syndrome in Brazilian families." Brazilian Journal of Genetics 20, no. 4 (December 1997): 731–39. http://dx.doi.org/10.1590/s0100-84551997000400028.

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We report on the cytogenetic and DNA analysis of 55 families with the fragile X (FMR-1 locus) mutation (318 individuals and 15 chorionic villi samples). A total of 129 males were investigated, 54 mentally normal and 75 presenting mental retardation. Among the 54 normal males, 11 had the premutation, and none expressed the fragile site. The full mutation was detected in 73 retarded males, and 14 (18%) presented a premutation along with the full mutation (mosaics). All of them manifested the fragile site. The frequencies of fragile site expression correlated positively with the sizes of the expansion of the CGG repeats (<FONT FACE="Symbol">D</FONT>). Among 153 normal females, 85 were found to be heterozygous for the premutation and 15 had the full mutation. In the premutated females the fragile site was not observed or it occurred at frequencies that did not differ from those observed in 53 noncarriers. Cytogenetic analysis was thus ineffective for the diagnosis of premutated males or females. Among the 51 heterozygotes for the full mutation, 36 (70%) had some degree of mental impairment. As in males, a positive correlation was detected between the frequencies of fragile site manifestation and the size of the expansion. However, the cytogenetic test was less effective for the detection of fully mutated females, than in the case of males, since 14% false negative results were found among females. Segregation analysis confirmed that the risk of mental retardation in the offspring of heterozygotes increases with the length of <FONT FACE="Symbol">D</FONT>. The average observed frequency of mental retardation in the offspring of all heterozygotes was 30%. There was no indication of meiotic drive occurring in female carriers, since the number of individuals who inherited the mutation did not differ from the number of those inheriting the normal allele. No new mutations were detected in the 55 genealogies studied here.

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Schmidt, Jan H. "Using Fast Frequency Hopping Technique to Improve Reliability of Underwater Communication System." Applied Sciences 10, no. 3 (February 10, 2020): 1172. http://dx.doi.org/10.3390/app10031172.

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Acoustic underwater communication systems designed to work reliably in shallow coastal waters must overcome major limitations such as multipath propagation and the Doppler effect. These restrictions are the reason for the complexity of receivers being built, whose task is to decode a symbol on the basis of the received signal. Additional complications are caused by the low propagation speed of the acoustic wave in the water and the relatively narrow bandwidth. Despite the continuous development of communication systems using coherent modulations, they are still not as reliable as is desirable for reliable data transmission applications. This article presents an acoustic underwater communication system that uses one of the varieties of the spread spectrum technique i.e., the fast frequency hopping technique (FFH). This technique takes advantage of binary frequency-shift keying (BFSK) with an incoherent detection method to ensure the implementation of a system whose main priority is reliable data transmission and secondary priority is the transmission rate. The compromised choice of parameters consisted of the selection between the narrow band of the hydroacoustic transducer and the maximum number of carrier frequency hops, which results from the need to take into account the effects of the Doppler effect. In turn, the number of hops and the symbol duration were selected adequately for the occurrence of multipath propagations of an acoustic wave. In addition, this article describes experimental communication tests carried out using a laboratory model of the FFH-BFSK data transmission system in the shallow water environment of Lake Wdzydze/Poland. The test results obtained for three channels of different lengths are discussed.

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Dias, Rafael, João Rebola, and Adolfo Cartaxo. "Outage Probability Due to Crosstalk from Multiple Interfering Cores in PAM4 Inter-Datacenter Connections." Photonics 8, no. 1 (January 3, 2021): 9. http://dx.doi.org/10.3390/photonics8010009.

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In this work, we propose to use four-level pulse amplitude modulation (PAM4) and multi-core fibers (MCFs) to support very high capacity datacenter interconnect (DCI) links. The limitations imposed by inter-core crosstalk (ICXT) on the performance of 112 Gb/s up to 80 km-long optically amplified PAM4 inter-DCI links with intensity-modulation and direct-detection and full chromatic dispersion compensation in the optical domain are analyzed through numerical simulation for high and low skew-symbol rate product (SSRP). With only one interfering core, we show that those PAM4 inter-DCI links achieve an outage probability (OP) of 10−4 with a maximum ICXT level of −13.9 dB for high SSRP and require an ICXT level reduction of about 8.1 dB to achieve the same OP for low SSRP. Due to using full dispersion compensation, for an OP of 10−4, the maximum acceptable ICXT level shows only a 1.4 dB variation with the MCF length increase from 10 km to 80 km. When considering the ICXT induced by several interfering cores, the maximum ICXT level per interfering core for an OP of 10−4 decreases around 3 dB when doubling the number of interfering cores. This conclusion holds for high and low SSRP regimes. For two interfering cores, we show that a single interfering core with low SSRP is enough to induce a severe reduction of the maximum acceptable ICXT level.

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Cherla, Srikanth, Hendrik Purwins, and Marco Marchini. "Automatic Phrase Continuation from Guitar and Bass Guitar Melodies." Computer Music Journal 37, no. 3 (September 2013): 68–81. http://dx.doi.org/10.1162/comj_a_00184.

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A framework is proposed for generating interesting, musically similar variations of a given monophonic melody. The focus is on pop/rock guitar and bass guitar melodies with the aim of eventual extensions to other instruments and musical styles. It is demonstrated here how learning musical style from segmented audio data can be formulated as an unsupervised learning problem to generate a symbolic representation. A melody is first segmented into a sequence of notes using onset detection and pitch estimation. A set of hierarchical, coarse-to-fine symbolic representations of the melody is generated by clustering pitch values at multiple similarity thresholds. The variance ratio criterion is then used to select the appropriate clustering levels in the hierarchy. Note onsets are aligned with beats, considering the estimated meter of the melody, to create a sequence of symbols that represent the rhythm in terms of onsets/rests and the metrical locations of their occurrence. A joint representation based on the cross-product of the pitch cluster indices and metrical locations is used to train the prediction model, a variable-length Markov chain. The melodies generated by the model were evaluated through a questionnaire by a group of experts, and received an overall positive response.

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Dharmadhikari, Susheel, Chandrachur Bhattacharya, Asok Ray, and Amrita Basak. "A Data-Driven Framework for Early-Stage Fatigue Damage Detection in Aluminum Alloys Using Ultrasonic Sensors." Machines 9, no. 10 (September 25, 2021): 211. http://dx.doi.org/10.3390/machines9100211.

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The paper presents a coupled machine learning and pattern recognition algorithm to enable early-stage fatigue damage detection in aerospace-grade aluminum alloys. U- and V-notched Al7075-T6 specimens are instrumented with a pair of ultrasonic sensors and, thereafter, tested on an MTS apparatus integrated with a confocal microscope and a digital microscope. The confocal microscope is focused on the notch root of the specimens, whereas the digital microscope is focused on the side of the notch. Two features, viz., the crack opening displacement (COD) and the crack length, are extracted during the tests in addition to the ultrasonic signal data. These signal data are analyzed using a machine learning framework that is built upon a symbolic time-series algorithm. This framework is interrogated for crack detection in the crack coalescence (CC) regime defined by COD of ~3 μm and detected through the confocal microscope. Additionally, the framework is probed in the crack propagation (CP) regime characterized by a crack length of ~0.2 mm and detected via the digital microscope. For the CC regime, training accuracies of 79.82% and 81.94% are achieved, whereas testing accuracies of 68.18% and 74.12% are observed for the U- and V-notched specimens, respectively. For the CP regime, overall training accuracies of 88.3% and 91.85% are observed, and accordingly, testing accuracies of 81.94% and 85.62% are obtained for the U- and V-notched specimens, respectively. The results show that a combined machine learning and pattern recognition algorithm enables robust and reliable fatigue damage detection in aerospace structural components.

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Becher, Karim Johannes, and Paweł Gładki. "Symbol length and stability index." Journal of Algebra 354, no. 1 (March 2012): 71–76. http://dx.doi.org/10.1016/j.jalgebra.2011.12.027.

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27

Chapman, Adam, and Kelly McKinnie. "Essential Dimension, Symbol Length and -rank." Canadian Mathematical Bulletin 63, no. 4 (February 4, 2020): 882–90. http://dx.doi.org/10.4153/s0008439520000119.

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AbstractWe prove that the essential dimension of central simple algebras of degree $p^{\ell m}$ and exponent $p^{m}$ over fields $F$ containing a base-field $k$ of characteristic $p$ is at least $\ell +1$ when $k$ is perfect. We do this by observing that the $p$-rank of $F$ bounds the symbol length in $\text{Br}_{p^{m}}(F)$ and that there exist indecomposable $p$-algebras of degree $p^{\ell m}$ and exponent $p^{m}$. We also prove that the symbol length of the Kato-Milne cohomology group $\text{H}_{p^{m}}^{n+1}(F)$ is bounded from above by $\binom{r}{n}$ where $r$ is the $p$-rank of the field, and provide upper and lower bounds for the essential dimension of Brauer classes of a given symbol length.

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28

Florence, Mathieu. "On the symbol length of -algebras." Compositio Mathematica 149, no. 8 (May 22, 2013): 1353–63. http://dx.doi.org/10.1112/s0010437x13007070.

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AbstractThe main result of this paper states that if $k$ is a field of characteristic $p\gt 0$ and $A/ k$ is a central simple algebra of index $d= {p}^{n} $ and exponent ${p}^{e} $, then $A$ is split by a purely inseparable extension of $k$ of the form $k( \sqrt[{p}^{e} ]{{a}_{i} }, i= 1, \ldots , d- 1)$. Combining this result with a theorem of Albert (for which we include a new proof), we get that any such algebra is Brauer equivalent to the tensor product of at most $d- 1$ cyclic algebras of degree ${p}^{e} $. This gives a drastic improvement upon previously known upper bounds.

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29

Fang, Yuting, Adam Noel, Nan Yang, Andrew W. Eckford, and Rodney A. Kennedy. "Symbol-by-Symbol Maximum Likelihood Detection for Cooperative Molecular Communication." IEEE Transactions on Communications 67, no. 7 (July 2019): 4885–99. http://dx.doi.org/10.1109/tcomm.2019.2910265.

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30

Jegbefume, O., M. Saquib, and M. Z. Win. "Soft-length symbol protocol for wireless networks." IEEE Communications Letters 9, no. 9 (September 2005): 793–95. http://dx.doi.org/10.1109/lcomm.2005.1506705.

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31

Lee, Suk-Hwan. "Reversible Data Hiding for DNA Sequence Using Multilevel Histogram Shifting." Security and Communication Networks 2018 (2018): 1–13. http://dx.doi.org/10.1155/2018/3530969.

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A large number of studies have examined DNA storage to achieve information hiding in DNA sequences with DNA computing technology. However, most data hiding methods are irreversible in that the original DNA sequence cannot be recovered from the watermarked DNA sequence. This study presents reversible data hiding methods based on multilevel histogram shifting to prevent biological mutations, preserve sequence length, increase watermark capacity, and facilitate blind detection/recovery. The main features of our method are as follows. First, we encode a sequence of nucleotide bases with four-character symbols into integer values using the numeric order. Second, we embed multiple bits in each integer value by multilevel histogram shifting of noncircular type (NHS) and circular type (CHS). Third, we prevent the generation of false start/stop codons by verifying whether a start/stop codon is included in an integer value or between adjacent integer values. The results of our experiments confirmed that the NHS- and CHS-based methods have higher watermark capacities than conventional methods in terms of supplementary data used for decoding. Moreover, unlike conventional methods, our methods do not generate false start/stop codons.

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32

Seymour, J. P., and M. P. Fitz. "Near-optimal symbol-by-symbol detection schemes for flat Rayleigh fading." IEEE Transactions on Communications 43, no. 2/3/4 (February 1995): 1525–33. http://dx.doi.org/10.1109/26.380202.

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33

Peng, Siming, Aijun Liu, Xinhai Tong, Ke Wang, and Giulio Colavolpe. "Optimal multicarrier faster-than-Nyquist signaling under symbol-by-symbol detection." Digital Signal Processing 72 (January 2018): 135–46. http://dx.doi.org/10.1016/j.dsp.2017.10.014.

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34

Divsalar, D., and M. K. Simon. "Multiple-symbol differential detection of MPSK." IEEE Transactions on Communications 38, no. 3 (March 1990): 300–308. http://dx.doi.org/10.1109/26.48887.

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35

Chapman, Adam. "Symbol length of p-algebras of prime exponent." Journal of Algebra and Its Applications 16, no. 07 (July 17, 2016): 1750136. http://dx.doi.org/10.1142/s0219498817501365.

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We prove that if the maximal dimension of an anisotropic homogeneous polynomial form of prime degree [Formula: see text] over a field [Formula: see text] with [Formula: see text] is a finite integer [Formula: see text] greater than 1 then the symbol length of [Formula: see text]-algebras of exponent [Formula: see text] over [Formula: see text] is bounded from above by [Formula: see text], and show that every two tensor products of symbol algebras of lengths [Formula: see text] and [Formula: see text] with [Formula: see text] can be modified so that they share a common slot. For [Formula: see text], we obtain an upper bound of [Formula: see text] for the symbol length, which is sharp when [Formula: see text].

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36

Lee, Daniel, Lih-feng Tsaur, and Muhammad Naeem. "Symbol-by-symbol CDMA spreading gain adaptation and detection using OVSF sequences." IEEE Transactions on Wireless Communications 8, no. 9 (September 2009): 4529–39. http://dx.doi.org/10.1109/twc.2009.071353.

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37

Nikara, J., S. Vassiliadis, J. Takala, and P. Liuha. "Multiple-symbol parallel decoding for variable length codes." IEEE Transactions on Very Large Scale Integration (VLSI) Systems 12, no. 7 (July 2004): 676–85. http://dx.doi.org/10.1109/tvlsi.2004.825840.

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38

Wilson, Denise L., Gilbert G. Kuperman, Eric G. Ramsey, and William A. Perez. "A Signal Detection Paradigm for Color Display Specification." Proceedings of the Human Factors Society Annual Meeting 32, no. 19 (October 1988): 1329–33. http://dx.doi.org/10.1177/154193128803201904.

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The objective of this research was to demonstrate the validity of signal detection theory to the assessment (visual discrimination) of displayed color symbology. The area of application of the research results is in the design specification of color coded symbology to be overlayed on moving map, situational awareness displays. A symbol detection experiment was designed to determine how far apart, in CIE/UCS color space, symbol and background color must be in order for observers to detect that a symbol is present against the background. Six trained observers viewed a number of systematically varied symbol/background color combinations and were required to make one of six responses along a continuum from “symbol definitely present” to “symbol definitely not present”. The analyses of the d' and Beta signal detection measures yielded different patterns of results, suggesting that this paradigm was successful in separating the cognitive and sensory/perceptual factors associated with color-on-color target detection. In addition, the shape of the Receiver Operating Characteristic (ROC) curves indicated that the assumptions underlying the signal detection paradigm were met.

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Steelman, Kelly S., and Hannah North. "Predicting Detection Times with Perceptual Euclidian Distance." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 60, no. 1 (September 2016): 1585–89. http://dx.doi.org/10.1177/1541931213601366.

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How should we select a set of symbol colors to optimize detection times? Here we suggest a simple, easy- to-calculate technique for predicting symbol detection times in cued and uncued visual search tasks. We used Perceptual Euclidian Distance (PED) to measure color similarity among symbols within the set (PEDset) and between each symbol color and the background color (PEDbg). Post hoc analyses of data from two previous change-detection experiments indicated that PEDbg was negatively correlated with detection time, but only in uncued visual search. PEDset, in contrast, was negatively correlated with detection time in cued search. In the current experiment, we designed a new symbology set that included three symbols that were equidistant in PED color space and a fourth symbol that was farther away in PED color space. We used this symbol set in a change detection experiment using the flicker paradigm. Consistent with the results of our previous analyses, we found that cued detection time was correlated with PEDset. Finally, we present a summary of data from seven experiments demonstrating that this pattern of effects holds over a variety of background colors and symbol sets. The overall results suggest that the PED may serve as an easy-to-use technique for selecting symbols that will facilitate particular performance objectives.

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40

Zhang, Runzhe, Eric Maggard, Yousun Bang, Minki Cho, Mark Shaw, and Jan Allebach. "Color Text Fading Detection." Electronic Imaging 2021, no. 16 (January 18, 2021): 253–1. http://dx.doi.org/10.2352/issn.2470-1173.2021.16.color-253.

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The text fading defect is one of the most common defects in electrophotographic printers; and it dramatically affects print quality. It usually appears in a significant symbol Region of Interest (ROI), easily noticed by a user on his or her print. We can detect text fading by the density reduction for the black and white printed symbol ROI. It is difficult to detect the color text fading only by density reduction, because the depleted cartridge may only cause the color distortion without density reduction in the color printed symbol ROI. In our previous work with print quality defects analysis, the text fading detection method only works for black text fading defect detection [1]. Our new text fading method can detect the color text fading defect and predict the depleted cartridge. In this new text fading detection method, we use whole page image registration and the median threshold bitmap (MTB) matching method to align the text characters between the master and test symbol ROIs, because with the aligned text characters, it is easy to extract the difference between the master and the test text characters to detect the text fading defect. We use a support vector machine classifier to assign a rank to the overall quality of the printed page. We also use the gap statistic method with the K-means clustering algorithm to extract the different text characters’ different colors to predict the depleted cartridge.

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41

Serpedin, Erchin. "Joint Blind Symbol Rate Estimation and Data Symbol Detection for Linearly Modulated Signals." Journal of Communications Software and Systems 5, no. 3 (September 21, 2009): 101. http://dx.doi.org/10.24138/jcomss.v5i3.204.

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This paper focuses on non-data aided estimation of the symbol rate and detecting the data symbols in linearlymodulated signals. A blind oversampling-based signal detector under the circumstance of unknown symbol period is proposed. First, the symbol rate is estimated using the Expectation Maximization (EM) algorithm. However, within the framework of EM algorithm, it is difficult to obtain a closed form for the loglikelihood function and the density function. Therefore, these two functions are approximated in this paper by using the Particle Filter (PF) technique. In addition, a symbol rate estimator that exploits the cyclic correlation information is proposed as an initialization estimator for the EM algorithm. Second, the blind data symbol detector based on the PF algorithm is designed.Since the signal is oversampled at the receiver side, a delayed multi-sampling PF detector is proposed to manage the intersymbol interference caused by oversampling, and to improve the demodulation performance of the data symbols. In the PF algorithm, the hybrid importance function is used to generate both data samples and channel model coefficients, and the Mixture Kalman Filter (MKF) algorithm is used to marginalize out the fading channel coefficients.

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42

Dong In Kim. "Selective maximum-likelihood symbol-by-symbol detection for multidimensional multicode WCDMA with precoding." IEEE Transactions on Communications 54, no. 4 (April 2006): 591–95. http://dx.doi.org/10.1109/tcomm.2006.873065.

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43

Lottici, Vincenzo, and Zhi Tian. "Multiple symbol differential detection for UWB communications." IEEE Transactions on Wireless Communications 7, no. 5 (May 2008): 1656–66. http://dx.doi.org/10.1109/twc.2008.060667.

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44

Simon, M. K., and M. S. Alouini. "Multiple symbol differential detection with diversity reception." IEEE Transactions on Communications 49, no. 8 (2001): 1312–19. http://dx.doi.org/10.1109/26.939840.

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45

Simon, M. K., and D. Divsalar. "Multiple symbol partially coherent detection of MPSK." IEEE Transactions on Communications 42, no. 2/3/4 (February 1994): 430–39. http://dx.doi.org/10.1109/tcomm.1994.577070.

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46

Debang Lao and A. M. Haimovich. "Multiple-symbol differential detection with interference suppression." IEEE Transactions on Communications 51, no. 2 (February 2003): 208–17. http://dx.doi.org/10.1109/tcomm.2003.809285.

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47

Zhou, Zhou, Lingjia Liu, and Hao-Hsuan Chang. "Learning for Detection: MIMO-OFDM Symbol Detection Through Downlink Pilots." IEEE Transactions on Wireless Communications 19, no. 6 (June 2020): 3712–26. http://dx.doi.org/10.1109/twc.2020.2976004.

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48

Mu, D., Z. Qiu, and X. Zhang. "UWB energy detection receiver based on multiple symbol differential detection." Electronics Letters 45, no. 19 (2009): 987. http://dx.doi.org/10.1049/el.2009.0980.

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49

Matzri, Eliyahu. "Symbol length in the Brauer group of a field." Transactions of the American Mathematical Society 368, no. 1 (April 15, 2015): 413–27. http://dx.doi.org/10.1090/tran/6326.

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50

Lee, Kang-Seok, Hosung Park, and Jong-Seon No. "New Binary Locally Repairable Codes with Locality 2 and Uneven Availabilities for Hot Data." Entropy 20, no. 9 (August 25, 2018): 636. http://dx.doi.org/10.3390/e20090636.

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In this paper, a new family of binary LRCs (BLRCs) with locality 2 and uneven availabilities for hot data is proposed, which has a high information symbol availability and low parity symbol availabilities for the local repair of distributed storage systems. The local repair of each information symbol for the proposed codes can be done not by accessing other information symbols but only by accessing parity symbols. The proposed BLRCs with k = 4 achieve the optimality on the information length for their given code length, minimum Hamming distance, locality, and availability in terms of the well-known theoretical upper bound.

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