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Tuna fisheries have become the most important contributor to the coastal central provinces of Vietnam since it was introduced in early 1990s. However, developing effective management guidelines for yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna, the main target species for longline and handline fisheries, is difficult because there is no information on its growth characteristics. In particular, length-length, length–weight, and weight-weight relationships, the important components of fisheries production models, do not exist for those species. This study first provided those relationship equations and represented an improvement in the knowledge of these species in its distribution range with maximum sizes updated.

Although investigating performances of existing chaotic communication systems (CCSs) and proposing new CCSs have been extensively investigated, designing antijamming (AJ) receivers for CCSs has been rarely considered. AJ receivers for CCS are of paramount importance in cases that the inherent AJ capability of CCSs does not work well, i.e., when the power of jamming signals is larger than that of chaotic signals. Motivated by this fact, in this article, we consider a differential chaos shift keying (DCSK) system under a Gaussian pulse jamming condition. We propose an AJ receiver with a hybrid blanking-clipping mechanism to enhance the AJ performance of the considered system. We also derive closed-form expressions of the signal-to-interference-plus-noise of the outputs of the blanking and clipping blocks, which are then to be used to obtain optimal blanking and clipping thresholds for additive white Gaussian noise (AWGN) channel. Moreover, an optimal weighting factor used for combining the outputs of the blanking and clipping blocks is also provided. We show that the proposed receiver considerably outperforms existing receivers.

Ultra wideband impulse (UWB) radars are getting much attention in the application of remote sensing of heart rate. UWB radar measures the heart rate by mean of the motion of thorax in the heartbeat activities. However, the signal of heartbeat is usually much smaller than the harmonics signal of respiration, then be easily perturbed. Thus, this paper proposed a multivariate correlation method (MCM) to improve the signal-to-noise ratio (SNR) of the heartbeat. The MCM is applied in the bandwidth of higher harmonics rather than the fundamental of heart rate to minimize the affection of the respiration signal. The experiments showed that the second harmonic of heart rate is good at minimizing the affection of the respiration signal, and the MCM is efficient to improve the SNR about 83.7 dB than the continuous wavelet transform method. The heart rate could be estimated with an average error of 2.54% compared with a referenced photoplethysmography sensor.

The Cai River catchment of the Ninh Thuan province locates in the South-central portion of Vietnam. This area is underlain by various rock types, including Mesozoic to Cenozoic sedimentary and volcanogenic sequences and a large volume of magmatic complexes. The Cenozoic sedimentary cover comprises thin units that are commonly deposited within small deltaic or fault-controlled alluvial basins, and along discontinuous narrow coastal plains. Pliocene-Quaternary basaltic bodies are locally covered part of the coastal zone or form small offshore volcanic islands. These assemblages are variably deformed and dismembered as consequence of long-lived tectonic movements. Recent tectonic activities are evident by numerous indicators, which include brittle fracture and fault systems straddling Quaternary sedimentary covers and recent weathering profiles, numerous fault scarps, abrupt local land uplift and/or subsidence, disruption of drainage systems, occurrence of earthquake, exposure of hot spring water and mud/sand volcanos. Other morpho-tectonic features such as the presence of Quaternary terraces, exposure and displacement of coral reef, and the development or significant modification of drainage patterns and modern basinal architecture have also resulted from active tectonic activities. Dating of the deformed materials, including fault gauge, uplifted, or subsided sediments reveal that the recent tectonic movements have taken place continually during the Late Holocene to recent. The combination of diverse lithologies, multiple tectonic fracturing and displacement of the rock units, tectonic uplift, and subsidence, in conjunction with the surface processes and sea action, have resulted in complex river course and coastal morphology. Active faulting and local tectonic movements have created long-term effects on the river flow pattern and coastal zone stability, including the shifting of flow direction, the formation of subsided or uplifted structures, sea-shore modification. Lateral tectonic movements, on the other hand, have led to the modification of the flow pattern, which consequently creates local complex flow patterns and associated hazards along the Cai River and its tributary.

In this paper, we consider the fundamental and most studied non-coherent differential chaotic shift keying system under a pulse jamming environment. We devote our effort to propose a novel correlation receiver with nonlinearity blanking for the considered system to improve its anti-jamming performance. In addition and importantly, we also propose a mathematical framework to derive an optimal blanking threshold for the proposed receiver. The proposed nonlinearity blanking mechanism basically blocks the received signals with a larger amplitude than the blanking threshold, while the signals with a smaller amplitude are not affected at all. We then show that the proposed receiver with optimal blanking threshold significantly outperforms the conventional correlation counterpart.

Time hopping spread spectrum (THSS) system and chaotic system have been studied as candidates of the anti-jamming (AJ) systems with substantial advantages. However, THSS systems suffer from the strict synchronization prerequisite. In order to overcome the shortcomings of the THSS system and utilize the profits of the non-coherent chaotic system, we first propose a novel TH-NRDCSK system to enhance the bit error rate (BER) performance of the conventional non-coherent THSS system and relieve the strict synchronization issue of coherent THSS systems. Then, we analyze the performance of the proposed system under additive white Gaussian noise (AWGN) channel and jamming environment. Finally, we implement the simulation to demonstrate the consistency of the analysis and the simulation results and to disclose the effects of the system parameters on system's AJ performance. Moreover, the performance of the proposed system is compared to that of conventional counterparts to look at the benefits of integrating chaotic and THSS systems. The simulation results show that the proposed system significantly outperforms conventional counterparts in a practical environment.

Ventricular fibrillation and ventricular tachycardia (VF/VT), known as shockable (SH) rhythms, are the mainly cause of sudden cardiac arrests (SCA), which is cured efficiently by the automated external defibrillator (AED). The performance of the shock advice algorithm (SAA) applied in the AED has been improved by using machine learning technique and variously conventional features, recently. In this paper, we propose a novel algorithm with relatively high performance for the SCA detection on electrocardiogram (ECG) signal. The algorithm consists of a convolutional neural network as a feature extractor (CNNE) and a Boosting (BS) classifier. A grid search with nested 5-folds cross validation (CV) is used to select the CNNE trained with preprocessed ECG, SH, and NSH signals using the modified variational mode decomposition technique. The deep feature vector learned by this CNNE is extracted at the first fully connected layer and then fed into BS classifier to validate its performance using 5-folds CV procedure. The secondary learning of the BS classifier and the use of three input channels for the CNNE improve certainly the detection performance of the proposed SAA with the validated accuracy of 99.26%, sensitivity of 97.07%, and specificity of 99.44%.

Summary Panax ginseng C. A. Meyer, reputed as the king of medicinal herbs, has slow growth, long generation time, low seed production and complicated genome structure that hamper its study. Here, we unveil the genomic architecture of tetraploid P. ginseng by de novo genome assembly, representing 2.98 Gbp with 59 352 annotated genes. Resequencing data indicated that diploid Panax species diverged in association with global warming in Southern Asia, and two North American species evolved via two intercontinental migrations. Two whole genome duplications (WGD) occurred in the family Araliaceae (including Panax) after divergence with the Apiaceae, the more recent one contributing to the ability of P. ginseng to overwinter, enabling it to spread broadly through the Northern Hemisphere. Functional and evolutionary analyses suggest that production of pharmacologically important dammarane‐type ginsenosides originated in Panax and are produced largely in shoot tissues and transported to roots; that newly evolved P. ginseng fatty acid desaturases increase freezing tolerance; and that unprecedented retention of chlorophyll a/b binding protein genes enables efficient photosynthesis under low light. A genome‐scale metabolic network provides a holistic view of Panax ginsenoside biosynthesis. This study provides valuable resources for improving medicinal values of ginseng either through genomics‐assisted breeding or metabolic engineering.

In this work, we consider an advanced noise reduction differential chaotic shift keying (NR-DCSK) system in which a single antenna source communicates with a single antenna destination under the attack of a single antenna jammer. We devote our efforts to design a novel anti-jamming (AJ) receiver for the considered system. Particularly, we propose a variational mode decomposition-independent component analysis-wavelet packet decomposition-based (VMD-ICA-WPD-based) structure, in which the VMD method is firstly exploited to generate multiple signals from the single received one. Secondly, the ICA method is applied to coarsely separate chaotic and jamming signals. After that, the WPD method is used to finely estimate and mitigate jamming signals that exist on all outputs of the ICA method. Finally, an inverse ICA procedure is carried out, followed by a summation, and the outcome is passed through the conventional correlation-based receiver for recovering the transmitted information. Simulation results show that the proposed receiver provides significant system performance enhancement compared to that given by the conventional correlation-based receiver with WPD, i.e. 8 dB gain at BER =0.03 and Eb/N0 = 20 dB., 5 pages, 5 figures

This paper considers the DCSK system under jamming environment. We consider both fast and slow switching pulse jamming (PJ). We derive approximations of the system bit error rates (BERs) in analytic expressions containing only well-known special functions, from which we show that for both jamming cases increasing the spreading factor can enhance the BER. In addition, we reveal that under the fast switching PJ, the BER does not depend on the jamming duty cycle ρ when ρ ≤ 0.5, however when ρ > 0.5, increasing its value degrades the BER. Moreover, we find out that under the slow switching PJ, increasing ρ may either enhance or degrade the BER.

For cooperative systems, in which an eavesdropper overhears source information through relays' transmission, an optimal relay selection (ORS) scheme has recently been proposed to improve the system secrecy performance. In this letter, we evaluate the secrecy outage probability (SOP) of the ORS scheme with an amplify-and-forward system over independent and non-identically distributed Rayleigh fading. More specifically, we derive a tight approximation on the SOP. Thereafter, by analyzing asymptotic behaviour of the derived approximation, novel insights are revealed. The derivations are confirmed through Monte Carlo simulations.

We consider a cooperative non-orthogonal multiple access system with radio frequency energy harvesting, in which a user with good channel harvests energy from its received signal and serves as a decode-and-forward relay for enhancing the performance of a user with poor channel. We here aim at maximizing the weighted sum rate of the system by optimizing the power allocation coefficient used at the source and the power splitting coefficient used at the user with good channel. By exploiting the specific structure of the considered problem, we propose a low-complexity one-dimensional search algorithm which can provide optimal solution to the problem. As a benchmark comparison, we derive analytic expressions and simple high signal-to-noise ratio (SNR) approximations of the ergodic rates achieved at two users and their weighted sum with fixed values of the power allocation and the power splitting coefficients, from which the scaling of the weighted sum in the high SNR region is revealed. Finally, we provided numerical results to demonstrate the validity of the optimized scheme. Index Terms-Cooperative NOMA, RF-energy harvesting, weighted sum rate analysis and optimization., Comment: 5 pages, 3 figures

We consider the inefficiencies of conventional multimedia broadcast multicast systems (CVM) limited by the user with worst signal-to-noise-ratio (SNR) and we present a novel technique based on amortized weighted averaging (AWG) of users' SNR. We model the system using ordered statistics of exponential and uniform distribution and derive statistics for the density functions. We then apply the modelling results to study the performance of wireless multicasting over Rayleigh fading channels. More specifically, we obtain the outage probability and mean capacities for broadcast and multicast systems. Finally we compare our proposed scheme with the conventional scheme. Numerical results show that proposed AWG is reliable, avoids outage, accommodates more users and is more efficient than the conventional multicasting especially in the low SNR region.

The relay selection method is a promising technique for improving the performance of cooperative systems. Most of the existing studies assume that wireless channels are statistically independent. However, in reality, channel correlation is more likely to be non-negligible. In this study, we investigate the dependence of the performance of cooperative systems with single relay selection in equally correlated environments. A tight upper bound of the system outage probability is given as a function of the channel correlation coefficients. We show that even though the system performance is considerably degraded in the high signal-to-noise ratio (SNR) region when the channel correlations are sufficiently large, yet less than one, the system still achieves a diversity order equal to the number of available relays.

In this paper, we consider an overlay cognitive radio network, in which a secondary transmitter (ST) is willing to relay the information of a primary transmitter toward a primary receiver. In return, ST can access the licensed band to send its own information superimposed with the primary signal to a secondary receiver. The power-limited ST uses a power splitting protocol to harvest energy from its received signal to increase its transmit power. We analyze the performance of the primary and the secondary systems under independent Nakagami- ${m}$ fading by deriving their corresponding outage probabilities in integral-based expressions. In addition, by considering the high signal-to-noise ratio, we obtain very tight closed-form approximations of the outage probabilities. Thereafter, by further analyzing the approximations, we reveal novel insights on the diversity orders and coding gains of the two systems. Our analytical results are validated through extensive Monte-Carlo simulations.

This paper investigates the anti-jamming performance of the NR-DCSK system. We consider several practical jamming environments including broad-band jamming (BBJ), partial-time jamming (PTJ), tone jamming (TJ) consisting of both single-tone and multi-tone, and sweep jamming (SWJ). We first analytically derived the bit error rates of the considered system under the BBJ and the PTJ environments in closed-form expressions. Our derived results show that the system performances under these two jamming environments are enhanced as $P$ increases, where $P$ is the parameter of the NR-DCSK modulation scheme denoting the number of times a chaotic sample is repeated. In addition, our results demonstrate that for the PTJ, the optimal value of the jamming factor is close to zero when the jamming power is small, however, it increases and approaches one as the jamming power enlarges. We then investigate the performance of the considered system under the TJ and the SWJ environments via Monte-Carlo simulations. Our simulations show that single-tone jamming causes a more significant performance degradation than that provided by multi-tone jamming counterparts. Moreover, we point out that the system performance is significantly degraded when the starting frequency of the sweep jammer is close to the carrier frequency of the transmitted chaotic signals, the sweep bandwidth is small, and the sweep time is half of the transmitted bit duration., Comment: 7 pages, 8 figures

In this paper, we consider amplify-and-forward (AnF) cooperative systems under correlated fading environments. We first present a brief overview of existing works on the effect of channel correlations on the system performance. We then focus on our main contribution which is analyzing the outage probability of a multi-AnF-relay system with the best relay selection (BRS) scheme under a condition that two channels of each relay, source-relay and relay-destination channels, are correlated. Using lower and upper bounds on the end-to-end received signal-to-noise ratio (SNR) at the destination, we derive corresponding upper and lower bounds on the system outage probability. We prove that the system can achieve a diversity order (DO) equal to the number of relays. In addition, and importantly, we show that the considered correlation form has a constructive effect on the system performance. In other words, the larger the correlation coefficient, the better system performance. Our analytic results are corroborated by extensive Monte-Carlo simulations.

After the first success with SigmaK3 [1], we have designed and developed the second 8-bit microprocessor chip, dubbed HN-07, with high performance and additional features. HN-07is based on the original Sigmak3 architecture with a number of improved features, namely 5-stage pipeline architecture, interrupt controller, more on-chip peripherals, higher operational stability and frequency. This improved architecture makes HN-07 microprocessor equivalent with others such as Intel 8051, Microchip PIC, etc. Our complete design, from front-end through back-end stages, has been taped out and supplied to an overseas foreign foundry for trial fabrication. Further detail on the evaluation of its performance will be reported in the future.

The complete chloroplast genome sequence of Panax vietnamensis, a medicinal herb belonging to Araliaceae family, was generated by de novo assembly using whole genome next-generation sequences. The chloroplast genome was a circular form of 155 992 bp long and showed typical chloroplast genome structure consisting of a large single-copy region of 86 177 bp, a small single copy region of 17 935 bp and a pair of inverted repeats of 25 940 bp. The chloroplast genome had 79 protein-coding genes, 29 tRNA genes and 4 rRNA genes. The phylogenetic analysis with the reported chloroplast genomes revealed that four Panax species were grouped in the same clade and P. vietnamensis is more closely related to P. notoginseng than P. ginseng and P. quinquefolius.

In this work, we consider the relay selection (RS) method for an Amplify-and-Forward (AnF) relaying system in multi-cell environments. The selection scheme aims to maximize the instantaneous received signal-to-noise and interference ratio (SINR). We propose an idea of combining RS with interference cancellation (IC) at the receiver. Furthermore, we analyze the system outage probability performance with the proposed scheme. We use approximation approach to simplify the derivation of the probability distributed function (PDF) of the received SINR. The system outage probability bound is also given. Simulation results validate our analysis, and show that our scheme greatly improves the system outage probability as well as bit-error-rate (BER) performances.

In this paper, the behavior of relay networks in interference environments is investigated. It has been shown that the effect of interference during Amplify-and-Forward process at relays bounds the diversity slope of the system at a well-defined static point. Moreover, the conventional relay selection criteria are also shown to be inefficient. To help our systems to improve its performance, the power allocation issue is taken into account with relay selection. However, solving a jointly optimization problem, optimizing transmitted power and maximizing the received SNR corresponding with the potential relay simultaneously, are difficult. In other words, it requires high complexity manipulation procedures. By proposing a power allocation and a relay selection separately, then combining these two methods, we form a new relay selection with power allocation-based mechanism that is less complex and has comparable performance with the optimal process.