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Recently, a two-dimension (2D) modulation waveform of orthogonal time-frequency-space (OTFS) has been a popular 6G candidate to replace existing orthogonal frequency division multiplexing (OFDM). The extensive OTFS researches help to make both the advantages and limitations of OTFS more and more clear. The limitations are not easy to overcome as they come from OTFS on-grid 2D convolution channel model. Instead of solving OTFS inborn challenges, this paper proposes a novel 2D modulation waveform named orthogonal time-frequency division multiplexing (OTFDM). OTFDM uses a 2D dot-product channel model to cope with doubly-selectivity. Compared with OTFS, OTFDM supports grid-free channel delay and Doppler and gains a simple and efficient 2D equalization. The concise dot-division equalization can be easily combined with MIMO. The simulation result shows that OTFDM is able to bear high mobility and greatly outperforms OFDM in doubly-selective channel., Comment: Accepted by IEEE PIMRC 2023

Cell-free massive MIMO provides ubiquitous connectivity for multiple users, and implementation using radio stripes is very efficient. Compared with collocated massive MIMO, the major cost includes fronthaul overheads and AP hardware. Maximum ratio combination (MRC) achieves a low fronthaul loading and low-cost AP, but the performance is bad. This letter proposes to implement a quasi-LMMSE (Q-LMMSE) processing using MRC fronthaul design. Q-LMMSE is derived from a standard LMMSE, which gains interference information from MRC signal via singular value decomposition. Simulation results show that the proposed Q-LMMSE increases the spectral efficiency by several times using same MRC fronthaul., arXiv admin note: text overlap with arXiv:2012.11076

Joint communications and sensing is a promising 6G technology, and the challenge is how to integrate them efficiently. Existing frequency-division and time-division coexistence can hardly bring a gain of integration. Directly using orthogonal frequency-division multiplexing (OFDM) to sense requires complex in-band full-duplex to cancel the selfinterference (SI). To solve these problems, this paper proposes novel coexistence schemes to gain super sensing range (SSR) and simple SI cancellation. SSR enables JCS to gain a sensing range of a sensing-only scheme and shares the resources with communications. Random time-division is proposed to gain a super Doppler range. Flexible sensing implanted OFDM (FSIOFDM) is also proposed. FSI-OFDM uses random sensing occasions to gain super Doppler range, as well as utilizes the fixed tail sensing occasions to achieve supper distance range. The simulation results show that the proposed schemes can gain SSR with limited resources.

Calmodulin-like interacting protein kinases play an important role in plant response to abiotic stresses and development. But the role of the CIPK gene in grapevine is unknown. In this study, VyCIPK1, isolated from the Chinese wild grape V. Yanshanesis, was strongly induced by salt stress. Overexpressing VyCIPK1 could induce AOC and AOS, and result in notably increased jamonate levels in tobacco. Under salt stress, transgenic plants showed higher germination rate, leaf number, and fresh weight than wild-type plants. Moreover, transgenic plants displayed higher chlorophyll content, catalase activity, peroxidase activity, superoxide dismutase activity, and lower malondialdehyde content, H2O2, and O2- content than that of wild type under salt stress conditions. And the stress-related genes, including ERD10C, ERD10D, LEA5, POD, SOD, and CAT, were up-regulated in transgenic plants. Our founding demonstrated that the VyCIPK1 has the potential for grape molecular breeding of salt tolerance as a candidate gene.

In this paper, a novel modulation and multiplexing technology for reducing out-of-band leakage is proposed for multicarrier schemes based on CP-OFDM. The proposed method is to spread data of N layers with N selected spreading codes, then multiplex them into a data sequence and transmit it on 2K subcarriers. The N spreading codes, which can suppress out-of-band leakage, are selected out from a complete set of mutual orthogonal spreading codes. The simulation results show that the data modulation and multiplexing technology effectively reduces interference with neighboring frequency bands or adjacent sub-bands for different numerologies and so significantly improves spectrum efficiency

Cell-free massive MIMO provides ubiquitous connectivity for multiple users, and implementation using radio stripes is very efficient. This paper proposes a parallel scheme for radio stripes to allow access point to do signal processing simultaneously. Simple maximum ratio (MR) processing works in this scheme, but its performance is bad. Therefore, this paper further proposes two efficient parallel schemes to gain better performance. The first is interference-aware MR processing with a tailored user-centric strategy. The second is distributed regularized zero-forcing (D-RZF) algorithm which derives from LMMSE. Simulation results show that the proposed parallel schemes gain better performance than existing works.

The focus of this white paper is on machine learning (ML) in wireless communications. 6G wireless communication networks will be the backbone of the digital transformation of societies by providing ubiquitous, reliable, and near-instant wireless connectivity for humans and machines. Recent advances in ML research has led enable a wide range of novel technologies such as self-driving vehicles and voice assistants. Such innovation is possible as a result of the availability of advanced ML models, large datasets, and high computational power. On the other hand, the ever-increasing demand for connectivity will require a lot of innovation in 6G wireless networks, and ML tools will play a major role in solving problems in the wireless domain. In this paper, we provide an overview of the vision of how ML will impact the wireless communication systems. We first give an overview of the ML methods that have the highest potential to be used in wireless networks. Then, we discuss the problems that can be solved by using ML in various layers of the network such as the physical layer, medium access layer, and application layer. Zero-touch optimization of wireless networks using ML is another interesting aspect that is discussed in this paper. Finally, at the end of each section, important research questions that the section aims to answer are presented.

To investigate the molecular mechanism underlying increasing leaf area in γ-Aminobutyric acid (GABA) biosynthetic mutants, the first pair of true leaves of GABA biosynthetic mutants was measured. The results showed that the leaf blade area in GABA biosynthetic mutants was larger than that of the wild type to different extents, and the area of the leaf epidermal cells in mutants was larger than that of the wild type. DNA polyploid analysis showed that polyploid cells in GABA biosynthetic mutants were appearing earlier and more abundant than in the wild type. To check the correlation between cell size and endoreplication, the expression of factors involving endocycles, including D-type cyclin gene (CYCD3;1, CYCD3;2, CYCD3;3, andCYCD4;1) and kinaseCKDA;1, were analysed by qRT-PCR. The results showed thatCKDA;1in GABA biosynthetic mutants was downregulated, and four types ofCYCDsshowed different expression patterns in different GABA biosynthetic mutants. Inconsistent with this result, forCCS52A(CELL CYCLE SWITCH 52A) (controlling the endocycle entry) ingad2andgad1/gad2mutants, the expression ofCCS52A2was significantly higher than that in the wild type. The expression ofSIM(SIAMESE) andSMR(SIAMESE-RELATED), which inhibit kinase activity, were also upregulated compared with the control. To further study the possible potential relationship between GABA metabolism and endoreplication, we analysed the reactive oxygen species (ROS) levels in guard cells using ROS fluorescent probes. ROS levels were significantly higher in GABA biosynthetic mutants than the control. All results indicated that cyclin, the cyclin-dependent kinase, and its inhibitory protein were coordinated to participate in endoreplication control at the transcription level in the leaves of GABA biosynthetic mutantArabidopsis.Contribution to the field statementγ-Aminobutyric acid (GABA) metabolic pathway plays a dual role in plant development. This research investigated the perturbation of GABA biosynthesis onArabidopsisleave endoreplication for the first time. In the GABA biosynthetic mutants, many genes, participating in cell division regulation, are coordinately transcriptionally expressed to trigger the onset and maintenance of endoreplication, and this led to the cell expansion and the increase leaf blade area. However, this initiation of endoreplication links with the decrease of endogenous GABA level and the increase Reactive oxygen species (ROS). This may be a compensation mechanism to adapt to abnormal GABA level in plant leaf development. Present evidence provided hypothesized that the normal GABA level in plant leaf development plays a brake to inhibit the immature cell expansion and differentiation, and this negative regulation functions a guarantee mechanism to watchdog the normal leaf development. In all, this contribution provides an updated perspective on the role of GABA in plant development.

In recent years, researchers have explored the interlayer stacking structure of the bilayer (BL) transition metal dichalcogenides (TMDCs) and found that it has unique impact on the electrical, optical, and vibrational properties of TMDCs. Unfortunately, the size of BL TMDCs synthesized by the pre-existing methods is not large. In addition, there is not any effective mean to control the number of layers as well as the stack structure. This is the major limiting factor for further exploration of the properties of BL TMDCs. We report a new method for the rapid and controllable growth of AB-stacked BL MoS2. Firstly, the mixed solution of Na2MoO4 and NaOH was spun on the sapphire substrate and then sulfurated. The BL MoS2 of AB-stacked can be obtained by changing the time of sulfur introduction. The size of the BL MoS2 is related to the parameters of sulfur. The maximum size of BL MoS2 grown by this method can reach 288 μm, and the average size can reach about 200 μm, which is larger than the size reported in most articles. In addition, the growth rate of BL MoS2 can be clearly increased by the spin-coating growth method and the fastest growth rate is up to 144 μm min−1, which is far higher than other published reports at present. Subsequently, a photodetector based on BL MoS2 was prepared. The response time of rising edge is about 0.32 ms, and that of falling edge is about 3.2 ms. The detector prepared by us shows excellent photoelectric detection performance. Therefore, the excellent performance of BL MoS2 makes it have a broad application prospect in the field of high-performance electronics and optoelectronics.

Traditionally farmers in China have relied on organic manures to build the organic matter content in soil and to fertilise crops for both human and livestock consumption. However, with requirements to increase food production, the use of relatively cheap inorganic fertilisers has increased, and manure nutrients are not always used to their potential. In addition, farms of all sizes and even biogas plants, often lack the basic infrastructure to manage manures; poor containment facilities often result in untreated manures being discharged directly into watercourses, whilst transportation of manures to the field and land spreading is often not mechanised and relies on availability of suitable labour. There is already clear evidence of overuse of nutrients in some parts of China and this is causing undesirable impacts on the environment. With the increasing demand for livestock products from a burgeoning population and changes in dietary preferences towards animal protein, greater quantities of manure nutrients will be generated in the next twenty years, especially in peri-urban concentrated animal feeding operations and intensive farms. It is essential that China addresses the infrastructural, research and communication challenges to ensure that manures are integrated into nutrient planning at the field, farm and regional level to safeguard the environment, reduce the requirement for inorganic fertiliser production and use, and improve farmer incomes. This paper reviews the current manure management practices, both nationally and, where appropriate, at a regional scale, and assesses what barriers currently prevent efficient manure nutrient utilisation in China. We then address the future challenges for manure nutrient management in China, before summarising key gaps in knowledge and communication with implications for research and policy.

Bayesian Personalized Ranking (BPR) is a representative pairwise learning method for optimizing recommendation models. It is widely known that the performance of BPR depends largely on the quality of negative sampler. In this paper, we make two contributions with respect to BPR. First, we find that sampling negative items from the whole space is unnecessary and may even degrade the performance. Second, focusing on the purchase feedback of E-commerce, we propose an effective sampler for BPR by leveraging the additional view data. In our proposed sampler, users' viewed interactions are considered as an intermediate feedback between those purchased and unobserved interactions. The pairwise rankings of user preference among these three types of interactions are jointly learned, and a user-oriented weighting strategy is considered during learning process, which is more effective and flexible. Compared to the vanilla BPR that applies a uniform sampler on all candidates, our view-enhanced sampler enhances BPR with a relative improvement over 37.03% and 16.40% on two real-world datasets. Our study demonstrates the importance of considering users' additional feedback when modeling their preference on different items, which avoids sampling negative items indiscriminately and inefficiently., Comment: submitted to IEEE Transactions on Knowledge and Data Engineering

In this paper, a novel multicarrier waveform called filter bank OFDM (FB-OFDM) is proposed for use in 5G. FB-OFDM adopts complex modulation and filtering on subcarrier level. It is compatible to CP-OFDM utilized by LTE and its transceiver can be implemented by simple polyphase filter. Moreover, FB-OFDM system can support asynchrony between subcarriers and choose pulse function adaptively under different scenarios. A pulse function that has good locality in both time and frequency domain is also constructed based on root raised cosine function. Simulation results are provided to validate the performance of FB-OFDM and the proposed pulse function.

In order to approach the characteristics of nitrogen and phosphorus pollution caused by cage culture and the balance of nitrogen and phosphorus during the process of cage culture, a monitoring was conducted in Daya Bay of Guangdong Province, China from April 2002 to Jane 2003. The results show that the concentrations of total nitrogen (TN) in the waters at the sites with five and ten years of cage culture history are 1.8 and 2.3 times of that at control site respectively. Ammonium (NH3-H) is the main form of nitrogen in spring while nitrate (NO 3 − ) in winter. The concentrations of TN, total dissolved nitrogen (TDN) and dissolved organic nitrogen (DON) are highest in autumn. The concentration of phosphorus increases with the increasing of the culturing time, among which phosphate (PO 4 3− ) increases most obviously. The concentrations of total phosphorus (TP) and total dissolved phosphorus (TDP) are highest in autumn. The nitrogen and phosphorus are accumulated significantly in the sediment of cage culture area. The model of N balance in the cage culture area: bait (70.62%) + fry (0.28%) + input by tide (14.8%) + release from sediment (14.3%) = harvest of adult fish (12.07%) + deposition into sediment (28.75%) + output by tide (56.18%) + others (3.00%). The model of P balance: bait (83.11%) + fry (0.17%) + input by tide (12.23%) + release from sediment (4.49%) = harvest of adult fish (8.43%) + deposition into sediment (48.59%) + output by tide (41.94%) + others (1.04%). In one fish growth year, the contents of nitrogen and phosphorus in harvest of adult fish are only 17.0% and 10.1% of the contents of nitrogen and phosphorus in fish bait and fry, wherein 83% of nitrogen and more than 89% of phosphorus in fish bait became marine pollutants.

Based on the typhoons and precipitation data, the article aims to analyze the typhoon influence on the precipitation in Hunan Province during from 1980 to 1998. The results showed that the typhoon rainstorms appeared forty-four times and affected Hunan at different degrees from 1980 to 1998. Meanwhile, thirty-two typhoon rainstorms were induced. That is to say, about average 1.68 times of the typhoon rainstorms appeared each year. Most of the typhoon rainstorms appeared from late July to early August. And these typhoon tracks are mostly westward or northwest near to Hunan province and the major landing area is Guangdong province.

In recent years, coherent structures in edge plasmas are believed to be one of the major factors in cross-field transport. The present dissertation is dedicated to using theoretical and numerical methods to study the dynamics of individual coherent structure, or so-called blob, moving from bulk plasma to the chamber wall. Blob is a filament structure extended along magnetic filed lines. We focus on two different types of blob. One is ending up at target plates, the other is not, i.e. the SOL and HB blobs. Two dimensional blob models are derived. Characteristic spatial scale , time scale , and velocity for blob are obtained and calculated for different tokamaks. They are in agreement with experimental measurements. Scaling analysis shows blob dynamics sensitive to spatial scale length. Stability analysis shows that blobs with spatial scales less than may move as coherent structures to large distances. In the SOL model simulation we have found the most structurally stable blob has scale length around . Blobs smaller than evolve into mushroom-like structures. Blobs larger than are subject to the fingering instability. Blobs with spatial scales close to can coherently move to long distances. Simulation results show that high density background effectively narrows down blob size and the inertia term in vorticity equation drives blob to mushroom shape and builds up vortex dipole within the structure. We also compare results with and without the Boussinesq approximation. In the HB model simulation it is shown that blobs have wider stable range. Their steep nose and long relaxation tail can explain experimentally detected asymmetric profile. HB blob moves with a constant velocity. In the biasing potential model a critical magnitude of the potential barrier is derived. A strong deformation of the blob as coherent structure will be observed while blob pass through a barrier higher than the critical value. Simulation results confirm the theoretical prediction. In the rotational blob model simulation results show the suppression of radial velocity and the generation of poloidal velocity. Fingering and mushroom effects are inhibited, but blobs evolve into rotational instability at later stage

The optimal solution of the "assignment problem" in maneuvering target tracking (MTT) is how to associate measurements with tracks correctly. It is critical in MTT. The earlier "traditional assignment algorithm" has poor performance because it does not consider missing and new targets. The modern augment assignment algorithm overcomes the two shortcomings above, but at the same time, the risk of error association probability becomes higher. This paper presents a new assignment algorithm-"soft assignment". It need not consider missing and new targets while it is an optimal solution based on the following two criteria: (1) the correct association probability is high; (2) the number of associations is near to the actual ones. The two criteria are presented in the form of function and the optimal solution using "soft assignment" can also be obtained.