A Message Passing Detection based Affine Frequency Division Multiplexing Communication System

The next generation of wireless communication technology is anticipated to address the communication reliability challenges encountered in high-speed mobile communication scenarios. An Orthogonal Time Frequency Space (OTFS) system has been introduced as a solution that effectively mitigates these issues. However, OTFS is associated with relatively high pilot overhead and multiuser multiplexing overhead. In response to these concerns within the OTFS framework, a novel modulation technology known as Affine Frequency Division Multiplexing (AFDM) which is based on the discrete affine Fourier transform has emerged. AFDM effectively resolves the challenges by achieving full diversity through parameter adjustments aligned with the channel's delay-Doppler profile. Consequently, AFDM is capable of achieving performance levels comparable to OTFS. As the research on AFDM detection is currently limited, we present a low-complexity yet efficient message passing (MP) algorithm. This algorithm handles joint interference cancellation and detection while capitalizing on the inherent sparsity of the channel. Based on simulation results, the MP detection algorithm outperforms Minimum Mean Square Error (MMSE) and Maximal Ratio Combining (MRC) detection techniques.Comment: 8 pages, 7 figure

Discovery of Potential piRNAs from Next Generation Sequences of the Sexually Mature Porcine Testes

Piwi- interacting RNAs (piRNAs), a new class of small RNAs discovered from mammalian testes, are involved in transcriptional silencing of retrotransposons and other genetic elements in germ line cells. In order to identify a full transcriptome set of piRNAs expressed in the sexually mature porcine testes, small RNA fractions were extracted and were subjected to a Solexa deep sequencing. We cloned 6,913,561 clean reads of Sus Scrofa small RNAs (18–30 nt) and performed functional characterization. Sus Scrofa small RNAs showed a bimodal length distribution with two peaks at 21 nt and 29 nt. Then from 938,328 deep-sequenced small RNAs (26–30 nt), 375,195 piRNAs were identified by a k-mer scheme and 326 piRNAs were identified by homology searches. All piRNAs predicted by the k-mer scheme were then mapped to swine genome by Short Oligonucleotide Analysis Package (SOAP), and 81.61% of all uniquely mapping piRNAs (197,673) were located to 1124 defined genomic regions (5.85 Mb). Within these regions, 536 and 501 piRNA clusters generally distributed across only minus or plus genomic strand, 48 piRNA clusters distributed on two strands but in a divergent manner, and 39 piRNA clusters distributed on two strands in an overlapping manner. Furthermore, expression pattern of 7 piRNAs identified by homology searches showed 5 piRNAs displayed a ubiquitous expression pattern, although 2 piRNAs were specifically expressed in the testes. Overall, our results provide new information of porcine piRNAs and their specific expression pattern in porcine testes suggests that piRNAs have a role in regulating spermatogenesis

Microarray-Based Approach Identifies Differentially Expressed MicroRNAs in Porcine Sexually Immature and Mature Testes

MicroRNAs (miRNAs) are short non-coding RNA molecules which are proved to be involved in mammalian spermatogenesis. Their expression and function in the porcine germ cells are not fully understood.We employed a miRNA microarray containing 1260 unique miRNA probes to evaluate the miRNA expression patterns between sexually immature (60-day) and mature (180-day) pig testes. One hundred and twenty nine miRNAs representing 164 reporter miRNAs were expressed differently (p<0.1). Fifty one miRNAs were significantly up-regulated and 78 miRNAs were down-regulated in mature testes. Nine of these differentially expressed miRNAs were validated using quantitative RT-PCR assay. Totally 15,919 putative miRNA-target sites were detected by using RNA22 method to align 445 NCBI pig cDNA sequences with these 129 differentially expressed miRNAs, and seven putative target genes involved in spermatogenesis including DAZL, RNF4 gene were simply confirmed by quantitative RT-PCR.Overall, the results of this study indicated specific miRNAs expression in porcine testes and suggested that miRNAs had a role in regulating spermatogenesis

Theoretical and Experimental Study on the Antisliding Performance of Casting Steel Cable Clamps

For large-span cable structures, a cable clamp is a key joint that connects adjacent structural components. In general, the antisliding performance of cable clamps determines their resistance capacity, and the antisliding force is generated by the clamping force induced by the high-strength bolts and the contact surfaces between the cable and the clamp. Since the existing methods are not sufficiently comprehensive for use to predict the precise bolt preload, a theoretical model developed by considering transversely isotropic material and the generalized Hook’s law is presented to predict the attenuation values of the bolt clamping force and the corresponding parameters. Then, to meet the requirements of Eurocode 3, a new laboratory test is performed to reveal the antisliding mechanism of cable clamps, considering the effects of long-term creep and cable tension. According to the results of the data collected by real-time monitoring, the actual ultimate antisliding force of the clamp and the comprehensive friction coefficient are determined. Finally, a comparative study between the theoretical results and the experimental results is conducted. The proposed theoretical model can predict the actual attenuation of the bolt clamping force after cable tension. The results show that the stiffness of the clamp plate should be minimized when designing the clamp to reduce the loss of the bolt preload

A Cumulative Expansion Force-Finding Method for Suspension-Cable Truss Composite Structure

Suspension-cable truss composite structure is a new type of cable-strut structure which combines the conventional cable structure with the rigid truss. By laying rigid roofing slabs, this composite structure offsets most effect of the wind suction, reduces the axial force of the stable cables, and reduces the large vertical displacement effectively when compared with conventional cable trusses. For this new structure, the deformation relevance between adjacent substructures results in a nonindependent and stable union. To effectively and precisely find the cable forces of a suspension-cable truss composite structure for the construction completion state, a proper optimization order and a suitable selection of the substructures are necessary. In this paper, the structural mechanical characteristics of the suspension-cable truss composite structure are introduced at first, to reveal the force transmission path between adjacent substructures. Secondly, the cumulative expansion force-finding method (CEFM) is proposed to obtain the optimal mode of the cable force distribution with a suitable operational efficiency. A numerical example is introduced and analyzed to verify the accuracy and feasibility of this method afterwards. The results show that CEFM could find out the optimal cable force distribution of the suspension-cable truss composite structure, with a geometry shape of whole structure and a rational stress level of all the components

A new Bayesian factor analysis method improves detection of genes and biological processes affected by perturbations in single-cell CRISPR screening

Clustered regularly interspaced short palindromic repeats (CRISPR) screening coupled with single-cell RNA sequencing has emerged as a powerful tool to characterize the effects of genetic perturbations on the whole transcriptome at a single-cell level. However, due to its sparsity and complex structure, analysis of single-cell CRISPR screening data is challenging. In particular, standard differential expression analysis methods are often underpowered to detect genes affected by CRISPR perturbations. We developed a statistical method for such data, called guided sparse factor analysis (GSFA). GSFA infers latent factors that represent coregulated genes or gene modules; by borrowing information from these factors, it infers the effects of genetic perturbations on individual genes. We demonstrated through extensive simulation studies that GSFA detects perturbation effects with much higher power than state-of-the-art methods. Using single-cell CRISPR data from human CD8+ T cells and neural progenitor cells, we showed that GSFA identified biologically relevant gene modules and specific genes affected by CRISPR perturbations, many of which were missed by existing methods, providing new insights into the functions of genes involved in T cell activation and neurodevelopment

Research on Key Technologies of the Non-Bracket Construction Method for an Annular Cable Supported Grid Structure

A cable strut structure uses a tension cable net as the main load-bearing system, which can allow full play of the high-strength material characteristics of the cables, greatly reduce the burden on the lower supporting system, and increase the span in an economic and effective manner. The annular cable supported grid structure is a new type of cable strut structure, which uses rigid grids to replace the flexible cables at the top chord of the spoke cable truss to meet the requirements of laying a heavy rigid roof. In this paper, first the structural mechanical characteristics of the annular cable supported grid structure are introduced, showing that the structural characteristics derived from the cable truss are the basis of non-bracket construction, while the presence of the upper grid results in difficulties with structure installation configuration control. Second, considering the characteristics of the cable supported grid structure and the difficulties in construction, the non-bracket construction method for annular cable supported grid structure with the commonly used nonlinear dynamic finite element method (NDFEM) in construction simulations is proposed. Finally, a numerical example is given and analyzed to verify the accuracy and feasibility of this method. The results indicate that the non-bracket construction technology proposed in this paper is suitable for the construction of a cable supported grid structure, and has the advantages of convenient prestress flow control, no need for brackets, simple and economical construction equipment, flexible arrangement of construction period, safe and reliable construction, and high construction accuracy

Experimental Investigation and Numerical Simulation of a Levy Hinged-Beam Cable Dome

According to existing rigid roofing projects, a new structure called the Levy hinged-beam cable dome is proposed. By replacing the upper flexible cables with hinged beams, rigid plates can be installed overhead. To fulfill the requirements of integral tow-lifting construction, the setting criteria for the temporary hinged joints on ridge beams were presented. An 8-m diameter specimen was manufactured and monitored to investigate the structural configurations during the accumulative traction-hoisting construction process. Finally, the specimen was tested under full-span and half-span loading conditions, while a numerical model was built to verify the experimental values. The results show that in the early stages of traction-hoisting, the structure establishes the overall prestress and finds its internal force balance, while the entire structure is in a shape of “ω”. As the component’s internal force increases during the construction steps, and the local deformations of the hinged beams gradually decrease, with the entire structure changing from “ω” to “m”, and finally reach their designed states. Under full-span loads, large local deformations occurred at the HB-3 hinges, while the bending stresses of these hinged beams were relatively small. Under half-span loads, the loading part exhibits a downward appearance, while the unloading part exhibits upward deflection