1,610 research outputs found

    Study on Complex Products Job-shop Scheduling System Based on MES

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    Various random disturbances that happen in the process of complex products (ship) production cannot feedback timely, and the plans of job-shop operation are too rough to instruct job-shop production. The purpose of this study is to solve the problems above, help the course of complex products (ship) job-shop production runs orderly and efficiently, and improve the job-shop on-site management level. In this paper, we proposed complex products job-shop scheduling system based on MES. The system adopts six-level, refined plan and scheduling mechanism. Its key part is the job-shop scheduling model with man-machine coordinated mechanism. What’s more, an improved Genetic Algorithm based on TOC is proposed to make the optimized algorithm module of the system more scientific and effective. Key words: Complex Products; MES; Job-shop Scheduling System; Man-machine Coordinated Mechanism; Genetic Algorithm Résumé: Diverses perturbations qui se produisent au hasard dans le processus de production des produits complexes (navire) ne peuvent pas être apperçues en temps opportun, et les plans de l'opération des ateliers sont trop approximatifs pour guider la production. Le but de cette étude consiste à résoudre les problèmes ci-dessus, rendre le cours de la production des produits complexes (ship) dans les ateliers ordonné et efficace et améliorer le niveau de gestion sur place. Dans cet article, nous avons proposé le système de planning des ateliers de produits complexes basé sur MES. Le système contient six niveaux de programmation raffinée et de mécanismes de planning. Son élément essentiel est le modèle de programmation avec les mécanismes de coordination homme-machine. De plus, un algorithme génétique amélioré basé sur TOC est également proposé de rendre le module de l'algorithme du système optimisé plus scientifique et efficace. Mots-clés: produits complexes; MES; système de planning des ateliers; mécanismes de coordination homme-machine; algorithme génétique 摘要:針對目前複雜產品(船舶)生產過程中所出現的各種隨機擾動不能得到及時回饋,以及車間作業計畫粗略難以直接指導車間生產的現狀,本文提出基於 MES的複雜產品車間作業調度系統。該系統採用逐層細化的五級計畫與調度機制,以人機協同的車間作業調度模型為核心,通過改進基於 TOC的遺傳演算法,使系統的演算法模組優化性能更具有科學性和操作性。該系統有助於實現複雜產品(船舶)車間生產過程的有序運作,從而提高生產車間的現場管理水準。 關鍵字:複雜產品; MES;車間作業調度;人機協同;遺傳演算

    Physical and chemical dual-confinement of polysulfides within hierarchically meso-microporous nitrogen-doped carbon nanocages for advanced Li-S batteries

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    Lithium–Sulfur (Li–S) batteries with high theoretical specific energy, environmentally benign and low cost are considered to be one of the most promising next-generation energy-storage systems compared with conventional lithium-ion batteries.</p

    catena-Poly[[(5-carb­oxy-2H-1,2,3-triazole-4-carboxyl­ato-κ2 N 3,O 4)sodium]-di-μ-aqua-κ4 O:O]

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    In the title coordination polymer, [Na(C4H2N3O4)(H2O)2]n, the NaI atom is six-coordinated by one O atom and one N atom from a 2H-1,2,3-triazole-4-carb­oxy-5-carboxyl­ate ligand and four O atoms from four water mol­ecules, forming a distorted octa­hedal geometry. The NaI atoms are bridged by water mol­ecules into a chain structure along [100]. Inter­molecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds connect the chains. An intra­molecular O—H⋯O hydrogen bond between the carboxyl­ate groups is observed

    Local k-NNs pattern in omni-direction graph convolution neural network for 3D point clouds

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    Effective representation of objects in irregular and unordered point clouds is one of the core challenges in 3D vision. Transforming point cloud into regular structures, such as 2D images and 3D voxels, are not ideal. It either obscures the inherent geometry information of 3D data or results in high computational complexity. Learning permutation invariance feature directly from raw 3D point clouds using deep neural network is a trend, such as PointNet and its variants, which are effective and computationally efficient. However, these methods are weak to reveal the spatial structure of 3D point clouds. Our method is delicately designed to capture both global and local spatial layout of point cloud by proposing a Local k-NNs Pattern in Omni-Direction Graph Convolution Neural Network architecture, called LKPO-GNN. Our method converts the unordered 3D point cloud into an ordered 1D sequence, to facilitate feeding the raw data into neural networks and simultaneously reducing the computational complexity. LKPO-GNN selects multi-directional k-NNs to form the local topological structure of a centroid, which describes local shapes in the point cloud. Afterwards, GNN is used to combine the local spatial structures and represent the unordered point clouds as a global graph. Experiments on ModelNet40, ShapeNetPart, ScanNet, and S3DIS datasets demonstrate that our proposed method outperforms most existing methods, which verifies the effectiveness and advantage of our work. Additionally, a deep analysis towards illustrating the rationality of our approach, in terms of the learned the topological structure feature, is provided. Source code is available at https://github.com/zwj12377/LKPO-GNN.git

    Patterns in leaf traits of woody species and their environmental determinants in a humid karstic forest in southwest China

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    IntroductionLeaf functional traits constitute a crucial component of plant functionality, providing insights into plants’ adaptability to the environment and their regulatory capacity in complex habitats. The response of leaf traits to environmental factors at the community level has garnered significant attention. Nevertheless, an examination of the environmental factors determining the spatial distribution of leaf traits in the karst region of southwest China remains absent.MethodsIn this study, we established a 25 ha plot within a karst forest and collected leaf samples from 144 woody species. We measured 14 leaf traits, including leaf area (LA), leaf thicknes (LT), specific leaf area (SLA), leaf length to width ratio (LW), leaf tissue density (LTD), leaf carbon concentration (LC), leaf nitrogen concentration (LN), and leaf phosphorus concentration (LP), leaf potassium concentration (LK), leaf calcium concentration (LCa), leaf magnesium Concentration (LMg), leaf carbon to nitrogen ratio (C/N), leaf carbon to phosphorus ratio (C/P), and leaf nitrogen to phosphorus ratio (N/P), to investigate the spatial distribution of community-level leaf traits and the response of the leaf trait community-weighted mean (CWM) to topographic, soil, and spatial factors.ResultsResults showed that the CWM of leaf traits display different spatial patterns, first, the highest CWM values for LT, LTD, C/N, and C/P at hilltops, second, the highest CWM values for LA, SLA, LW, LC, LN, LP, and LK at depressions, and third, the highest CWM values for LCa, LMg, and N/P at slopes. The correlation analysis showed that topographic factors were more correlated with leaf trait CWM than soil factors, with elevation and slope being the strongest correlations. RDA analysis showed that topographic factors explained higher percentage of leaf trait CWM than soil factors, with the highest percentage of 19.96% being explained by elevation among topographic factors. Variance Partitioning Analysis showed that the spatial distribution of leaf traits is predominantly influenced by the combined effects of topography and spatial factors (37%-47% explained), followed by purely spatial factors (24%-36% explained).DiscussionThe results could improve our understanding of community functional traits and their influencing factors in the karst region, which will contribute to a deeper understanding of the mechanisms that shape plant communities

    Ram pressure stripping in elliptical galaxies: I. the impact of the interstellar medium turbulence

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    Elliptical galaxies contain X-ray emitting gas that is subject to continuous ram pressure stripping over timescales comparable to cluster ages. The gas in these galaxies is not in perfect hydrostatic equilibrium. Supernova feedback, stellar winds, or active galactic nuclei (AGN) feedback can significantly perturb the interstellar medium (ISM). Using hydrodynamical simulations, we investigate the effect of subsonic turbulence in the hot ISM on the ram pressure stripping process in early-type galaxies. We find that galaxies with more turbulent ISM produce longer, wider, and more smoothly distributed tails of the stripped ISM than those characterised by weaker ISM turbulence. Our main conclusion is that even very weak internal turbulence, at the level of <15% of the average ISM sound speed, can significantly accelerate the gas removal from galaxies via ram pressure stripping. The magnitude of this effect increases sharply with the strength of turbulence. As most of the gas stripping takes place near the boundary between the ISM and the intraclustermedium (ICM), the boost in the ISM stripping rate is due to the "random walk" of the ISM from the central regions of the galactic potential well to larger distances, where the ram pressure is able to permanently remove the gas from galaxies. The ICM can be temporarily trapped inside the galactic potential well due to the mixing of the turbulent ISM with the ICM. The galaxies with more turbulent ISM, yet still characterised by very weak turbulence, can hold larger amounts of the ICM. [Abridged]Comment: 12 pages, 11 figures, 2 tables; accepted for publication in MNRA

    The Effect of Apolipoprotein E Polymorphism on Lipid Levels in Korean Adults

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    The aim of this study was to determine the effects of polymorphisms in the apolipoprotein E gene (APOE) on lipid levels in Korean adults and to investigate the interactions between these polymorphisms and environmental factors in determining lipid levels. We performed a cross-sectional study of 1,900 subjects (668 men and 1,232 women; 45-74 yr old) in Namwon, Korea, in 2004. APOE polymorphisms were determined by polymerase chain reaction and restriction enzyme analysis. Carriers of the APOE*E2 (E2) allele had significantly lower total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations than did carriers of the APOE*E3 (E3) or APOE*E4 (E4) alleles, regardless of gender. The APOE allele type had significant effect on high-density lipoprotein cholesterol (HDL-C) and triglyceride levels in women, but not in men. The effect of APOE allele type on HDL-C levels was modified by age in women. In addition, in men, the effect of APOE allele type on triglyceride levels was modified by smoking. These findings highlight the important effect of gene-environment interactions on lipid levels

    Seasonality of the Transpiration Fraction and Its Controls Across Typical Ecosystems Within the Heihe River Basin

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    Understanding the seasonality of the transpiration fraction (T/ET) of total terrestrial evapotranspiration (ET) is vital for coupling ecological and hydrological systems and quantifying the heterogeneity among various ecosystems. In this study, a two‐source model was used to estimate T/ET in five ecosystems over the Heihe River Basin. In situ measurements of daily energy flux, sap flow, and surface soil temperature were compared with model outputs for 2014 and 2015. Agreement between model predictions and observations demonstrates good performance in capturing the ecosystem seasonality of T/ET. In addition, sensitivity analysis indicated that the model is insensitive to errors in measured input variables and parameters. T/ET among the five sites showed only slight interannual fluctuations while exhibited significant seasonality. All the ecosystems presented a single‐peak trend, reaching the maximum value in July and fluctuating day to day. During the growing season, average T/ET was the highest for the cropland ecosystem (0.80 ± 0.13), followed by the alpine meadow ecosystem (0.79 ± 0.12), the desert riparian forest Populus euphratica (0.67 ± 0.07), the Tamarix ramosissima Ledeb desert riparian shrub ecosystem (0.67 ± 0.06), and the alpine swamp meadow (0.55 ± 0.23). Leaf area index exerted a first‐order control on T/ET and showed divergence among the five ecosystems because of different vegetation dynamics and environmental conditions (e.g., water availability or vapor pressure deficits). This study quantified transpiration fraction across diverse ecosystems within the same water basin and emphasized the biotic controls on the seasonality of the transpiration fraction
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