Propagation Method Research Articles

Multi-stream graph attention network for recommendation with knowledge graph

In recent years, the powerful modeling ability of Graph Neural Networks (GNNs) has led to their widespread use in knowledge-aware recommender systems. However, existing GNN-based methods for information propagation among entities in knowledge graphs (KGs) may not efficiently filter out less informative entities. To address this challenge and improve the encoding of high-order structure information among many entities, we propose an end-to-end neural network-based method called Multi-stream Graph Attention Network (MSGAT). MSGAT explicitly discriminates the importance of entities from four critical perspectives and recursively propagates neighbor embeddings to refine the target node. Specifically, we use an attention mechanism from the user's perspective to distill the domain nodes' information of the predicted item in the KG, enhance the user's information on items, and generate the feature representation of the predicted item. We also propose a multi-stream attention mechanism to aggregate user history click item's neighborhood entity information in the KG and generate the user's feature representation. We conduct extensive experiments on three real datasets for movies, music, and books, and the empirical results demonstrate that MSGAT outperforms current state-of-the-art baselines.

Variety Breeding Studies on Hesperis isatidea (Boİss.) D.A. German & Al-Shehbaz

Hesperis isatidea (Boiss.) D.A.German & Al-Shehbaz, a member of the Brassicaceae family, represents a distinctive natural species characterized by its fragrant, conspicuous inflorescences, unique flower coloration, and distinct feather-like foliage. The Turkish name of the species is known as “Allı Gelin”. This species is native, exhibiting resilience to drought conditions and requiring minimal care. Cultivation studies on this species were carried out at Erzincan Horticulture Research Institute (Turkey) with project number 106G022 within the scope of TÜBİTAK (Turkish Scientific and Technological Research Council). The research aimed to determine optimal production techniques through generative and vegetative propagation methods. The project, initiated in 2013 and concluded in 2022, focused on developing a cultivar of the Allı Gelin plant using texel selection breeding techniques. Thirteen populations of Allı Gelin from institute's gene pool were utilized. Employing the Texel Selection method, four distinct lines were identified: compact, tightly spread compact, pyramid1and pyramid-2 shaped. Subsequent baby plant tests revealed stability in the tightly spread compact and pyramid-1 lines, leading to their selection for further breeding. Although breeding efforts continued on the compact line, the pyramid-2 line was discontinued due to an inability to attain the desired stability. The successfully tested variants, namely the pyramid-1 and tightly spread compact forms, have been earmarked as candidates for outdoor ornamental plant varieties. Registration procedures for these candidates are underway. These new varieties promise to enrich diversity within the ornamental plants sector, potentially enhancing competitiveness in foreign markets.

Fatigue crack evaluation of butt weld joints in full-scale aluminum alloy joints: Experimental and numerical study of traction structural stress

In this study, the digital image correlation technique is used to determine the inconsistent mechanical properties and microstructure non-uniformity in different regions of aluminum alloy butt welded joints. A state monitoring method is proposed based on phased-array ultrasonic total focus imaging for crack evolution. A series of surface fatigue crack propagation tests on full-scale aluminum alloy butt welds are investigated, which innovatively revealed the mechanism and evolution law of crack propagation at the surface of the weld. The analytical function for dynamic crack propagation in welded structures is proposed, which provides a new idea and data support for clarifying the state deterioration process of structures. The results show that the traction structural stress can effectively identify the critical fatigue position of the weld and effectively account for the effect of angular misalignment. The phased-array ultrasonic total-focus imaging monitoring analysis method for surface fatigue crack propagation is proposed to improve the completeness of the fatigue crack evolution law.

Mining Delay Propagation Causality within an Airport Network from Historical Data

Airport networks are interconnected through flight routes, with delays at upstream airports leading to delays at downstream airports, thus causing delay propagation. Exploring the mechanisms of delay propagation in airport networks provides scientific insights for managing and controlling delays in aviation systems. Existing methods, such as Granger causality tests and transfer entropy, must be revised to address the nonlinear causal relationships of delays in airport networks. So, this paper proposes a causality mining method for delay propagation in airport networks based on partial correlation-based multivariate conditional independence (PCMCI). This method comprehensively considers all airports and causality mining in two stages. The first stage uses conditional independence tests to obtain the parent node set of the target airport, which includes both true and false causal relationships. The second stage employs instantaneous conditional independence tests to eliminate false causal relationships and obtain test statistics representing the strength of causality. Based on historical delay data from US airports over a year, the experimental results show that multiple factors cause delay propagation in airport networks rather than a single causal relationship. The scope of delay propagation is limited, mainly affecting a few airports closely connected to it. Delays at airports with small flight volumes are more likely to propagate. Few airport pairs in the network mutually propagate delays and, often, delays at airports affected by a particular airport’s delay also exhibit causal relationships with each other. This method provides a new perspective for deepening the understanding of delay propagation mechanisms in airport networks.

In Situ and Ex Situ Conservation of Ornamental Geophytes in Poland

The protection of biological diversity in nature and in agriculture, including the production of ornamental crops, has become increasingly important in Poland as well as worldwide. The Convention on Biological Diversity, signed in 1992 at the Earth Summit of the UN in Rio de Janeiro and ratified by the Polish government in 1995, imposed new regulations related to the protection of nature and the genetic resources of cultivated crops in Poland. The conservation of the genera, varieties and cultivars of ornamental geophytes—a group of plants of great interest from a botanical and physiological, but also a horticultural point of view—takes place in situ (both in nature and in the places of cultivation) and through the establishment of ex situ gene banks and collections. The natural genetic resources of ornamental geophytes include species from the genera Allium, Fritillaria, Gladiolus, Iris, Leucojum, Lilium and Muscari, among others, and more than a dozen species are protected by law due to varying degrees of threats. Botanical gardens play an essential role in the conservation of endangered species. Their activities focus on genus monitoring, managing ex situ gene banks (including National Collections), developing propagation methods and carrying out their reintroduction. In order to protect the national genetic resources of cultivated plants, the National Centre for Plant Genetic Resources at the Plant Breeding and Acclimatisation Institute—National Research Institute, under the auspices of the Ministry of Agriculture and Rural Development, was established. Concerning ornamental geophytes, the National Centre coordinates two field collections of cultivars of the genera Gladiolus, Lilium, Narcissus and Tulipa, which are of great economic importance and have a long tradition of breeding in Poland. The first one is located at the National Institute of Horticultural Research in Skierniewice (central Poland), and the second one is at the Experimental Substation of Variety Testing in Lisewo (northern Poland). The history of tulip collections in Poland dates back to the 1960s. At that time, the first breeding work for this species began. The collection of bulbous crops in Skierniewice is currently one of the largest in Poland, with a total of 934 accessions. Most of them are tulips (522) and lilies (222). Other plants in the collection in Skierniewice are gladiolus and narcissus. The most valuable accessions are grown under special protection (tunnels with dense nets) to guard against insects and maintain a mild climate inside. The genetic resources of the ornamental bulb plant collection in Lisewo currently consist of 611 accessions, mainly tulips (358), daffodils (121) and gladioli (132). All bulbous crops in both collections (Skierniewice and Lisewo) are grown in accordance with all principles of agrotechnics (negative field selection, fertilisation, soil maintenance). A particularly important task of botanical gardens, universities, research institutes and the National Centre is leading research on the methods of storage for survival organs, in vitro cultures and cryopreservation. We have discovered that the various activities for the species conservation of ornamental geophytes require a great deal of constantly deepening knowledge and extraordinary measures, including frequent monitoring of the effects of the applied measures.

Exact derivative propagation method to compute the generalized compliance matrix for continuum robots: Application to concentric tubes continuum robots

This paper introduces the concept of Generalized Compliance for continuum robots, specifically for those modeled with the Cosserat Rod theory. Unlike existing models based on tip compliance, the proposed approach considers interactions along the entire body of the flexible robot. The paper also presents a novel method referred to as the Low-Level Derivative Propagation Method, which is designed for the computationally efficient derivation of the Generalized Compliance matrix. The proposed method streamlines calculations and reduces integration time. The presented method, which is general and applies to various types of continuum robot models, is demonstrated on the case of a Concentric Tubes Continuum Robot. We provide detailed derivations of the equations and computation techniques leading to the derivation of the Generalized Compliance matrix, as well as a large-scale numerical validation of the method. The code used in this paper is available on the following GitHub website: https://github.com/benoitrosa/Generalized-Compliance-Computation-for-Continuum-Robots.

Investigation on the vibration damping effect of the tapered circular cylindrical shell based on wave propagation method

Investigation on the vibration damping effect of the tapered circular cylindrical shell based on wave propagation method

SC-AOF: A Sliding Camera and Asymmetric Optical-Flow-Based Blending Method for Image Stitching.

Parallax processing and structure preservation have long been important and challenging tasks in image stitching. In this paper, an image stitching method based on sliding camera to eliminate perspective deformation and asymmetric optical flow to solve parallax is proposed. By maintaining the viewpoint of two input images in the mosaic non-overlapping area and creating a virtual camera by interpolation in the overlapping area, the viewpoint is gradually transformed from one to another so as to complete the smooth transition of the two image viewpoints and reduce perspective deformation. Two coarsely aligned warped images are generated with the help of a global projection plane. After that, the optical flow propagation and gradient descent method are used to quickly calculate the bidirectional asymmetric optical flow between the two warped images, and the optical-flow-based method is used to further align the two warped images to reduce parallax. In the image blending, the softmax function and registration error are used to adjust the width of the blending area, further eliminating ghosting and reducing parallax. Finally, by comparing our method with APAP, AANAP, SPHP, SPW, TFT, and REW, it has been proven that our method can not only effectively solve perspective deformation, but also gives more natural transitions between images. At the same time, our method can robustly reduce local misalignment in various scenarios, with higher structural similarity index. A scoring method combining subjective and objective evaluations of perspective deformation, local alignment and runtime is defined and used to rate all methods, where our method ranks first.

A guided wave propagation method for delamination detection in fiber-metal laminates

This study aimed to assess the delamination detection in FMLs via the finite element (FE) simulations of Lamb wave propagation. An FE model of an FML specimen with [Al/902/Al/902/Al] layup was developed. Delamination damage of 10 and 25 mm diameters was induced between different layers of the FML specimen. The fundamental antisymmetric Lamb wave mode (A0) at 60 kHz and the fundamental symmetric Lamb wave mode (S0) at the frequency of 206 kHz were propagated on the developed FE models. The Lamb wave phase velocity was obtained from the FE models and compared with those obtained from the Lamb wave propagation tests. The sensitivity of the A0 and S0 Lamb wave modes to the delamination and its diameter were examined. The inverse Lamb wave propagation problem was then solved, and the elastic modulus of the FML specimen was estimated in the intact and delamination regions. It was observed that the phase velocity of the S0 Lamb wave mode had a higher sensitivity to the delamination damage compared to that of the A0 Lamb wave mode. The phase velocity of the A0 Lamb wave mode was more sensitive to the delamination diameter. The capability of the proposed simulated Lamb wave propagation method as a virtual lab for detecting delamination in the FMLs was confirmed.

Physiological and biochemical aspects of successful stenting in Rosa hybrida L.: Role of rootstock

Stenting is a commercial propagation method for roses that combines grafting and cutting in one action and the resulting plantlet is named ‘stentling’. Several physiological and biochemical factors can significantly influence graft union healing and adventitious root formation. The effect of rootstock and its cutting-prepared region have not been well studied for successful stenting. We provide a comprehensive overview of the physiological and biochemical aspects of the stenting process, utilizing rootstock positions as the source of variation among treatments. Morphophysiological and biochemical assays were performed to evaluate the effect of three different stem parts (bottom, middle, and top) of ‘Natal Briar’ as rootstock on graft union healing and adventitious root formation of the rose stentlings. When the rootstock originating from the bottom and middle positions improved the physiological, biochemical, and morphological responses of the stentling, significantly. In this regard, the improved biochemical properties, including total soluble sugars, total phenolic and flavonoid contents, phenylalanine ammonia-lyase, peroxidase and lignin content seem to play a special role in the success of grafting and subsequently the adventitious root formation. Assessing morphophysiological and biochemical parameters paves the way for a better understanding of the mechanism of successful stenting.

Planar and ridged waveguide preparation on erbium pre-implanted fused silica by multi-energy helium ion implantation and femtosecond laser ablation

Ion implantation stands as a highly competitive technique for fabricating optical waveguide structures within photoelectric materials. In this work, both planar and ridge waveguides have been successfully realized on fused silica. The fabrication process begins with the implantation of erbium ions into fused silica, utilizing an energy of 400 keV and a fluence of 5×1015ions/cm2 to produce a fluorescence effect. Following this, helium ions are implanted at varying energies −450, 500, and 550 keV-with a consistent fluence of 3.2×1016ions/cm2 to create a planar waveguide structure. Subsequently, the ridge waveguide is meticulously prepared through the application of laser ablation, leveraging the pre-existing planar waveguide as a foundation. The guide mode of the planar waveguide is characterized at a wavelength of 632.8 nm using the prism coupling method. Additionally, the near-field light intensity distribution at the same wavelength is assessed via the end-face coupling technique and further analyzed using the finite-difference beam propagation method. To substantiate the practical utility of these waveguides, measurements of the propagation loss and fluorescence properties are conducted.

Using Constraint Propagation to Bound Linear Programs

We present an approach to compute bounds on the optimal value of linear programs based on constraint propagation. Given a feasible dual solution, we apply constraint propagation to the complementary slackness conditions and, if propagation succeeds to prove these conditions infeasible, the infeasibility certificate (in the sense of Farkas’ lemma) is reconstructed from the propagation history. This certificate is a dual-improving direction, which allows us to improve the bound. As constraint propagation need not always detect infeasibility of a linear inequality system, the method is not guaranteed to converge to a global solution of the linear program but only to an upper bound, whose tightness depends on the structure of the program and the used propagation method. The approach is suited for large sparse linear programs (such as LP relaxations of combinatorial optimization problems), for which the classical LP algorithms may be infeasible, if only for their super-linear space complexity. The approach can be seen as a generalization of the Virtual Arc Consistency (VAC) algorithm to bound the LP relaxation of the Weighted CSP (WCSP). We newly apply it to the LP relaxation of the Weighted Max-SAT problem, experimentally showing that the obtained bounds are often not far from optima of the relaxation and proving that they are exact for known tractable subclasses of Weighted Max-SAT.

Diversity, Indigenous Uses and Conservation Status of Plants Used in Socio-Cultural Traditions by Kinnaura Tribes of Himachal Pradesh, India

Himachal Pradesh, one of India's Western Himalayan states, is well-known for its distinct culture, traditions and vegetation. Kinnaura is a major tribal community of Himachal Pradesh and for ages, these people are highly dependent on locally available plant resources for fulfilling daily livelihood needs including socio-cultural traditions. Therefore, an effort has been made to; (i) assess the diversity and utilization pattern of plant resources in socio-cultural traditions; (ii) identify endemism and nativity and the threat status of these species; and (iii) suggest management options for conservation. A total of 105 species belonging to 79 genera and 39 families representing trees (14 species), shrubs (17 species), herbs (73 species) and one climber were recorded. Among these, fifty-two species were native to the Himalayan region and fifteen species were near-endemic. Flowers of plants are used in the majority. Among these, eighteen species are in the various threat categories of threatened species. Due to increasing demand, habitat destruction and overexploitation, the population of the preferred species are depleting rapidly. Therefore, assessment of natural populations, demand and supply studies, harvesting trends, developments of propagation methods, afforestation of highly preferred species and community awareness for sustainable utilization and conservation of traditional knowledge have been suggested.

A dimension reduction-based Kriging modeling method for high-dimensional time-variant uncertainty propagation and global sensitivity analysis

Surrogate models have been widely used in the uncertainty propagation and global sensitivity analysis of complex evaluation-expensive engineering problems. However, the construction of high-accuracy surrogate models for time-variant problems with high-dimensional inputs and outputs using a small number of training samples remains a challenge. To address this challenge, we propose a dimension reduction-based Kriging modeling (KMDR) method for high-dimensional time-variant uncertainty propagation and global sensitivity analysis. Singular value decomposition is performed on the original time-variant response to extract principal components from high-dimensional outputs. And the improved sufficient dimension reduction (ISDR) is performed on high-dimensional inputs to identify the latent input space with respect to each principal component of outputs. A ladle estimator with a rigorous mathematical definition is then employed to determine the number of principal components of the outputs and the dimensionalities of the latent input spaces. The ladle estimator considers variabilities in both eigenvalues and eigenvectors of a matrix and can determine the latent dimensionality more accurately and efficiently than existing approaches. Subsequently, Kriging models between high-dimensional inputs and each principal component of the outputs are constructed based on a newly devised Kriging kernel, which embeds the information of the ISDR into the kernel function and can achieve higher accuracy than directly constructing Kriging models between latent inputs and outputs. In addition, a generalized variance-based sensitivity index, which can quantify the effects of the inputs on the overall time-variant response, is defined and computed directly from Sobol’ sensitivity indices of the inputs at each time node. Finally, the surrogate model of the time-variant system constructed by the KMDR is directly adopted for efficient time-variant uncertainty propagation and global sensitivity analysis. Several examples demonstrate that the proposed approach can construct more accurate surrogate models and obtain more accurate time-variant uncertainty propagation and global sensitivity analysis results than existing methods with a small training set.

Ab Initio Electron Propagators with an Hermitian, Intermediately Normalized Superoperator Metric Applied to Vertical Electron Affinities.

New-generation ab initio electron propagator methods for calculating electron detachment energies of closed-shell molecules and anions have surpassed their predecessors' accuracy and computational efficiency. Derived from an Hermitian, intermediately normalized superoperator metric, these methods contain no adjustable parameters. To assess their versatility, a standard set (NIST-50-EA) of 50 vertical electron affinities of small closed-shell molecules based on NIST reference data has been created. Errors with respect to reference data on 23 large, conjugated organic photovoltaic (OPV23) molecules have also been analyzed. All final states are valence anions that correspond to electron affinities between 0.2 and 4.2 eV. For a given scaling of the arithmetic bottleneck, the new-generation methods obtain the lowest mean absolute errors (MAEs). The best methods with fifth-power arithmetic scaling realize MAEs below 0.1 eV. Composite models comprising cubically and quintically scaling calculations executed with large and small basis sets, respectively, produce OPV23 MAEs near 0.05 eV. The accuracy of quintically scaling methods executed with large basis sets is thereby procured with reduced computational effort. New-generation results obtained with and without the diagonal self-energy approximation in the canonical Hartree-Fock basis have been compared. These results indicate that Dyson orbitals closely resemble canonical Hartree-Fock orbitals multiplied by the square root of a probability factor above 0.85.

Application of revitalize liquid biocomplex to increase adaptability of grapes at planting in open ground conditions

At present, the range of modern grape varieties suitable for cultivation in the conditions of the Non-Black Earth zone of the Russian Federation is represented by hybrids of different species origin derived from Vitis berlandieri Planch., Vitis Amurensis Rupr., Vitis riparia Michx., Vitis Labrusca L., which are characterized by low ability to vegetative propagation. Therefore, the development of techniques to improve the technology of accelerated propagation of these varieties, including the technology of clonal micropropagation is currently urgent. However, most studies in the field of in vitro propagation of grapes are devoted to laboratory experiments, but there is little information on the influence of the propagation method on the development indicators and vegetative productivity of grape mother plantations in protected and open ground conditions. Therefore, the purpose of this study was to develop methods of application of Revitalize liquid to increase the adaptability and stress resistance of ex vitro grape plants during summer transplanting into the open ground to create mother plantations. The research objectives are to reveal the effectiveness of feeding (root, foliar, combined) with Revitalize liquid during summer transplanting ex vitro grape plants of grape varieties Kishmish № 342, Moscow White and Kober 5BB rootstock into the open ground. The obtained results indicate that double combined treatments (root 500 ml: 500 ml H2O + foliar 25 ml:1000 ml H2O) are effective for pre-growing of ex vitro mother plants of Kishmish № 342 and Kober 5BB rootstock in open ground conditions, and double root feeding (at a concentration of 25 ml:1000 ml H2O) with Revitalize liquid is promising for Moscow White variety.

Field performance of grafted, micropropagated, and own-rooted plants of three Italian hazelnut cultivars during the initial four seasons of development.

Over the course of four consecutive years, a comparative study, for the first time, was carried out to assess their growth characteristics, vegetative and productive performances. Micropropagated, grafted on not suckering rootstock and own-rooted plants by layering from three Italian hazelnut (Corylus avellana L.) cultivars were established in the same orchard and environmental condition. We found that the micropropagated plants, regardless of the variety considered, even being smaller than the other plants at the beginning of the plantation, reached similar sizes as the other plants after four growing seasons. Furthermore, micropropagated plants exhibited greater uniformity in growth compared to grafted ones, while own-rooted plants displayed more variability. No significant differences in yield performance and canopy volume were observed among the three propagation methods. These results suggest that the in vitro propagation technique, even in hazelnut, allows standardizing the plant material while preserving cultivar characteristics. Finally, in vitro propagation as well as grafting can be safely recommended for the cultivation of hazelnut cultivars.

A modified displacement discontinuity method for seismic wave propagation across rock masses with thin-layer joints

Seismic wave propagation across rock masses with thin-layer joints by the modified displacement discontinuity method (M-DDM) is of great importance for geophysical surveys. The M-DDM introduces a frequency-dependent effective stiffness to describe the dynamic stress-closure relationship of a thin-layer joint. We verify the accuracy of M-DDM in studying seismic wave propagation across rock masses with thin-layer joints. Subsequently, we evaluate the influence of the joint thickness and the incident wave frequency on M-DDM accuracy. We analyze the prediction error of the transmission coefficient obtained with M-DDM. The results demonstrate that the frequency-dependent effective joint stiffness increases with increasing incident wave frequency and decreases with increasing joint thickness. Compared with the traditional displacement discontinuity method (DDM), M-DDM more accurately predicts the transmission coefficients of seismic waves propagating across thin-layer joints. The transmission coefficient prediction error obtained based on M-DDM increases with increasing joint thickness and incident wave frequency and is always smaller than that obtained based on DDM. Therefore, the M-DDM can be used to effectively investigate seismic wave propagation across rock masses with thin-layer joints.

Exogenous methyl jasmonate (MeJA) altered phytochemical composition and enhanced the expression of PatAACT gene of in vitro culture-derived patchouli var. Sidikalang (Pogostemon cablin Benth.)

The demand for economically valuable terpenoid-derived compounds, especially those extracted from patchouli plants, is experiencing exponential growth. These compounds are potentially applied in a wide range of industrial sectors including food manufacturing, perfumeries, and pharmaceuticals. Nevertheless, there is a need for further development in patchouli plant cultivation to align with market demands. Therefore, employing robust in vitro-based propagation methods could offer significant advantages. Furthermore, this technique is also used for plant metabolites enhancement. This strategy applies the methyl jasmonate (MeJA) elicitor to boost the production of secondary metabolites. In Indonesia, patchouli var. Sidikalang is extensively cultivated in many areas. This study aims to evaluate the effect of naphtaleneacetic acid (NAA) and 6-benzylamino purine (BAP) to increase plant growth via in vitro culture. Furthermore, we also investigate the effect of MeJA on the metabolite profiles and on the AACT gene expression. Our findings revealed that the combination of 2.5 µM of BAP and 0.25 µM of NAA resulted in optimal growth and high rate of organogenesis across all growth parameters. Our data also successfully identified 50 dominant compounds, each with varying percentage areas. Notably, patchouli alcohol emerged as the primary compound in the tricyclic sesquiterpene group, consistently present in all treatment groups. Furthermore, the expression of the PatAACT gene significantly increased by 7.42-fold after treatment with MeJA at 100 µM and by 2,9-fold after treatment with MeJA at 300 µM, compared to the control. Altogether, our findings might offer new insight in P. cablin propagation and new strategy for patchouli-derived metabolites using exogenous MeJA.

A hybrid variational method for beam propagation and interaction in a graded-index nonlinear waveguide

The hybrid variational method can be used to simplify multidimensional numerical simulations. We examine the applicability of this method to study the nonlinear propagation of a single beam and the interference of two spatial soliton beams in a graded-index optical waveguide governed by a two-dimensional nonlinear Schrodinger equation. We classified three distinct regimes of the dynamics that emerge during single Gaussian beam propagation, corresponding to beam decay, breather formation, and self-focusing. When two spatial soliton beams were set up to interfere in the waveguide, we identified the boundary where the nonlinear interaction during the interference led to excitation or self-focusing. These quite involved dynamics were used to test the predictive power of our variational models by comparing them with direct numerical simulations, obtaining good agreement.