symmetrical structure
Recently Published Documents





2022 ◽  
pp. 1-1
Shizheng Sun ◽  
Yu Han ◽  
Hui Zhang ◽  
Zeyin He ◽  
Qifu Tang

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8369
Yizhi Luo ◽  
Zhixiong Zeng ◽  
Huazhong Lu ◽  
Enli Lv

In this paper, a lightweight channel-wise attention model is proposed for the real-time detection of five representative pig postures: standing, lying on the belly, lying on the side, sitting, and mounting. An optimized compressed block with symmetrical structure is proposed based on model structure and parameter statistics, and the efficient channel attention modules are considered as a channel-wise mechanism to improve the model architecture.The results show that the algorithm’s average precision in detecting standing, lying on the belly, lying on the side, sitting, and mounting is 97.7%, 95.2%, 95.7%, 87.5%, and 84.1%, respectively, and the speed of inference is around 63 ms (CPU = i7, RAM = 8G) per postures image. Compared with state-of-the-art models (ResNet50, Darknet53, CSPDarknet53, MobileNetV3-Large, and MobileNetV3-Small), the proposed model has fewer model parameters and lower computation complexity. The statistical results of the postures (with continuous 24 h monitoring) show that some pigs will eat in the early morning, and the peak of the pig’s feeding appears after the input of new feed, which reflects the health of the pig herd for farmers.

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2224
Haiping Gao ◽  
Jian Zhu ◽  
Xianyong Li ◽  
Xing Chen

In this paper, several multi-layer-coupled star-composed networks with similar symmetrical structures are defined by using the theory of graph operation. The supra-Laplacian matrix of the corresponding multi-layer networks is obtained according to the master stability equation (MSF). Two important indexes that reflect the synchronizability of these kinds of networks are derived in the case of bounded and unbounded synchronized regions. The relationships among the synchronizability, the number of layers, the length of the paths, the branchings, and the interlayer and intralayer coupling strengths in the two cases are studied. At the same time, the simulation experiments are carried out with the MATLAB software, and the simulated images of the two symmetrical structure networks’ synchronizability are compared. Finally, the factors affecting the synchronizability of multi-layer-coupled star-composed networks are found. On this basis, optimization schemes are given to improve the synchronizability of multi-layer-coupled star-composed networks and the influences of the number of central nodes on the networks’ synchronizability are further studied.

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2165
Andrei Bencze ◽  
Maria Luminița Scutaru ◽  
Marin Marin ◽  
Sorin Vlase ◽  
Ana Toderiță

The paper aims to analyze the vibrations of a summing box, used in heavy vehicles. An experimental setup is proposed and used for the analysis of these vibrations transmitted by the box housing, based on the measurement of the mechanical impedance. It is then shown that a simpler measurement, namely that of the generated noise spectrum, can provide equally useful results, with less effort and in a shorter time. The experimental setup is much simpler, involving a sonometer arranged in the experimental assembly. The symmetry of the box allows us to facilitate the execution of the experimental assembly, and the use of the symmetrical structure to facilitate the calculation of vibrations. The results obtained using this method in the case of a redesigned adder box are presented in the paper.

2021 ◽  
Vol 73 (1) ◽  
Ilia Palaguta ◽  
Elena Starkova

There are two collections that are stored in Saint Petersburg originating from the first LBK sites (Floreşti I andNiezwiska) investigated in the USSR during the 1950-60s by Tatiana Passek and Katerina Chernysh. Despite the incompleteness of this material, it allows us to make several observations regarding technical aspects of pottery production and its ornamentation. The production of LBK vessels is based on a coiling with subsequent forming by the “paddle-and-anvil” technique. Principal distinctions between production techniques make it possible to exclude the idea of links between the LBK and the subsequent Precucuteni-Tripolye A culture. The specifics of the forms and techniques of LBK ornamentation allows to propose that such ornamentation originates from non-ceramic prototypes. Additionally, the symmetrical analysis of Eastern LBK ornamentation indicates differences in symmetry preferences between the LBK and Cucuteni-Tripolye populations. According to the hypothesis of D. K. Washburn (2018), such a difference may indicate distinctions in the social structures of these cultures.

Larisa N. Lunkova ◽  
Julia I. Frolova

The article considers the notional nature and peculiarities of genus-species relations between the phenomena of opposition and oppositivity ; it also deals with the lexical-and-grammatica ways of expressing the latter in an English literary text. The study establishes that, besides the logical component, an opposition also expresses a subjective one, manifesting a communicants unique view on the communicative situation and thus displaying semantics of oppositivity. Unlike spatial, logical and grammatical oppositions, generally characterized by a symmetrical structure, the subjective (oppositive) opposition is asymmetrical. It is revealed that due to the structural asymmetry this kind of opposition is marked by greater semantic potential compared to logical and grammatical oppositions. It is proved that the complication of subjective oppositions with antonymous pairs, lexical and syntactical repetitions, antithetic units, oxymorons etc. extends the scope of meanings implied by them; and the use of subjective (oppositive) oppositions in a literary text themselves becomes an effective tool of contrast-building both on the lexical-grammatical and textual levels.

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5589
Pengnian Yang ◽  
Zhixun Xia ◽  
Likun Ma ◽  
Binbin Chen ◽  
Yunchao Feng ◽  

The solid scramjet has become one of the most promising engine types. In this paper, we report the first direct-connect test of a solid scramjet with symmetrical structure, carried out using boron-based fuel-rich solid propellant as fuel. During the test, which simulated a flight environment at Mach 5.6 and 25 km, the performance of the solid scramjet was obtained by measuring the pressure, thrust, and mass flow. The results show that, due to the change in the combustion area of the propellant and the deposition of the throat in the gas generator during the test, the equivalence ratio gradually increased from 0.54 to 0.63. In a solid scramjet, it is possible to obtain a symmetrical distribution of the flow field within the combustor. Moreover, in a multi-cavity combustor, the combustion state expands from the cavity to the center of the flow channel. The performance of the solid scramjet increased during the test, reaching a combustion efficiency of about 42%, a total pressure recovery coefficient of 0.35, and a thrust gain specific impulse of about 418 s. The solid scramjet with symmetrical structure is feasible. The cavity configuration adopted in this paper can reduce the ignition delay time of fuel-rich gas and improve the combustion efficiency of gas-phase combustible components. The shock trains in the isolator are conducive to the recovery of the total pressure. The performance of the solid scramjet is limited by the low combustion efficiency of the particles.

2021 ◽  
Vol 7 (9) ◽  
pp. 710
Erzsébet Fekete ◽  
Fruzsina Pénzes ◽  
Norbert Ág ◽  
Claudio Scazzocchio ◽  
Michel Flipphi ◽  

Spliceosomal introns are pervasive in eukaryotes. Intron gains and losses have occurred throughout evolution, but the origin of new introns is unclear. Stwintrons are complex intervening sequences where one of the sequence elements (5′-donor, lariat branch point element or 3′-acceptor) necessary for excision of a U2 intron (external intron) is itself interrupted by a second (internal) U2 intron. In Hypoxylaceae, a family of endophytic fungi, we uncovered scores of donor-disrupted stwintrons with striking sequence similarity among themselves and also with canonical introns. Intron–exon structure comparisons suggest that these stwintrons have proliferated within diverging taxa but also give rise to proliferating canonical introns in some genomes. The proliferated (stw)introns have integrated seamlessly at novel gene positions. The recently proliferated (stw)introns appear to originate from a conserved ancestral stwintron characterised by terminal inverted repeats (45–55 nucleotides), a highly symmetrical structure that may allow the formation of a double-stranded intron RNA molecule. No short tandem duplications flank the putatively inserted intervening sequences, which excludes a DNA transposition-based mechanism of proliferation. It is tempting to suggest that this highly symmetrical structure may have a role in intron proliferation by (an)other mechanism(s).

Sign in / Sign up

Export Citation Format

Share Document