Cooperative Task Scheduling and Planning Considering Resource Conflicts and Precedence Constraints

Donghui Li,Hu Su,Xinyi Xu,Qingbin Wang,Jie Qin,Wei Zou 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.9

The robot-task-sequencing planning problem is investigated in this paper, where multi-robot tasks with resource conflicts and precedence constraints are involved making the problem challenging and complex. An effective approach is proposed to minimize the production cycle time while handling the high complexity effectively. The approach decouples the entire problem into simpler ones and then solves them separately to obtain the final solution. Firstly, given the multi-robot tasks, how to coordinate the operation of each single robot is determined. This is achieved by searching the shortest path in the graph where the tasks are organized in the optimal order without the consideration of resource constraints. Then, the resource allocation is modeled as a constrained assignment problem with the objective of minimal cycle time, which is solved with graph optimization. Consequently, the best-fit robot configurations for task execution are selected according to a heuristic optimality metric, based on which the task execution sequence obtained in previous steps is re-optimized. Finally, the robots involved in the task are regarded as a whole to deduce feasible trajectories. Experimental results demonstrate that the proposed approach can generate solutions where the robot can complete the given tasks effectively with feasible scheduling. Moreover, the proposed approach is successfully implemented in a pragmatic system which tests signals at both ends of components in a circuit board.

Prediction of operating reliability of multi-body mechanism in micro-switches considering parameter distribution and wear of parts

Donghui Li,Xue Zhou,Sanqiang Ling,Yue Jin,Guofu Zhai 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Traditional method evaluates operating reliability by counting life-test results of a small number of samples, which ignores variability between individuals and cannot accurately reflect the true state. This paper proposes a model for predicting operational reliability of mechanism in a batch of micro-switches based on manufacturing parameters, in view of complex structure and diverse manufacturing parameters. A multi-body kinetic model based on manufacturing parameters and principle of action considering contact fatigue and wear was established, and the operating characteristics in the degradation process with sliding wear of joints were obtained. Finally, the linkage with revolute clearance in miniature circuit breaker (MCB) was used as numerical example application to perform investigation. Prediction results are consistent with batch experiments, which verifies accuracy of model. In addition, the optimal combination of clearances was obtained by using genetic algorithm based on predicted model, which increases locking reliability to 99.3 % after 10000 operation cycles.

A simulated experimental system and risk prediction method for ignition caused by overhead lines short-circuit

Donghui Li,Yuguang Zhong,Xue Zhou,Guofu Zhai 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In windy weather, overhead lines swing and collide with each other, often resulting in short-circuits and arc faults. The line is partially molten and produces numerous hot metal particles, which fall and may ignite the fuels on the ground. This paper developed an experimental system to obtain hot particle dimensions at different short-circuit current levels. Based on the results of this experiment, an ignition prediction method was developed. The particle parameters from the experiments were used as a bridge that to complete the prediction from short-circuit current to ignition risk. A neural network was trained according to the experimental and calculated results, then used to predict the risk of ignition. The overhead lines in a forest were used as an example application to perform thte investigation. The results show that copper lines in a forest with needles on the ground create a high risk of ignition hazard.

The Studies for Building Failure Characteristics of the Extraordinarily Fire Explosion Accident in Tianjin Port

Jialiang Li,Donghui Ma 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

To research the failure characteristics on the extraordinarily fire explosion accident which happened in Tianjin Port, through detailed site investigation and related numerical calculation, a new formula of the shock wave overpressure which can be used in near field and far field are proposed, and the formula was contrasted and validated with the actual damage. Finally, according to the explosive power and the distance from explosive source, the damaging range is divided into different damage levels. In this paper, some salient characteristics of the fire explosion accident are discovered and discussed. The results indicates that this model can depict the damage situation well in near field and far field and it can supplement and revise the planning on earthquake resistance and hazardous prevention.

Extension of indacenodithiophene backbone conjugation enables efficient asymmetric A-D-A type non-fullerene acceptors

Song, Jiali,Li, Chao,Ye, Linglong,Koh, Changwoo,Cai, Yunhao,Wei, Donghui,Woo, Han Young,Sun, Yanming The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.39

<P>A novel strategy involving judiciously fusing one thiophene/thieno[3,2-<I>b</I>]thiophene on only one side of an indacenodithiophene (IDT) unit to extend IDT backbone conjugation was developed, and three A-D-A type non-fullerene small molecules (TPT-2F, TPTT-2F, and TPTTT-2F) were designed and synthesized to investigate the influence of the extent of IDT core conjugation on their photovoltaic properties. Extending the IDT core conjugation could broaden absorption, upshift the lowest unoccupied molecular orbital (LUMO) energy level, enhance electron mobility, and increase intermolecular π-π stacking. When these three non-fullerene acceptors were applied in organic solar cells (OSCs), simultaneous enhancement of the open-circuit voltage (<I>V</I>oc), short-circuit current (<I>J</I>sc), and fill factor (FF) was obtained, with the degree of enhancement following the order TPT-2F < TPTT-2F < TPTTT-2F. As a result, the TPTTT-2F based OSCs yielded a high PCE of 12.03%. To the best of our knowledge, the PCE of 12.03% is among the highest values for asymmetric non-fullerene acceptor based OSCs so far. These results demonstrate that extending the conjugation of the IDT core is an effective approach to design highly efficient asymmetric non-fullerene acceptors.</P>

Robust H∞ controller based on linear matrix inequalities for grid‑connected inverters in weak grids

Fanqing Zhou,Donghui Li,Ningyi Liang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.10

The problems of grid impedance fluctuations and harmonic interference exist widely in grid-connected inverter systems in a weak grid. A robust H∞ control strategy based on linear matrix inequalities (LMIs) is proposed to solve these problems. The proposed strategy improves the adaptation of inverters to a weak grid and the quality of the grid output current. First, an LCL-type grid-connected inverter model with a resonant controller is established. A reduced-order generalized integratorensures zero-error tracking of grid current and grid harmonics suppression in the resonant controller. The inverter model, delayed session and resonant controller model are integrated into a polytopic model that describes an uncertain system. Then, a robust H∞ controller is designed to control the integrated polytopic uncertainty model based on LMIs. A suitable optimization condition is designed for the controller gain to avoid violent oscillations of the system. Finally, a hardware-in-the-loop experiment is performed to validate the effectiveness of the suggested approach.

<i>De novo</i> genetic variation associated with retrotransposon activation, genomic rearrangements and trait variation in a recombinant inbred line population of <i>Brassica napus</i> derived from interspecific hybridization with <i>Brassica rapa</i>

Zou, Jun,Fu, Donghui,Gong, Huihui,Qian, Wei,Xia, Wei,Pires, J. Chris,Li, RuiYuan,Long, Yan,Mason, Annaliese S.,Yang, Tae‐,Jin,Lim, Yong P.,Park, Beom S.,Meng, Jinling Blackwell Publishing Ltd 2011 The Plant journal Vol.68 No.2

<P><B>Summary</B></P><P>Interspecific hybridization is a significant evolutionary force as well as a powerful method for crop breeding. Partial substitution of the AA subgenome in <I>Brassica napus</I> (A<SUP>n</SUP>A<SUP>n</SUP>C<SUP>n</SUP>C<SUP>n</SUP>) with the <I>Brassica rapa</I> (A<SUP>r</SUP>A<SUP>r</SUP>) genome by two rounds of interspecific hybridization resulted in a new introgressed type of <I>B.?napus</I> (A<SUP>r</SUP>A<SUP>r</SUP>C<SUP>n</SUP>C<SUP>n</SUP>). In this study, we construct a population of recombinant inbred lines of the new introgressed type of <I>B.?napus</I>. Microsatellite, intron‐based and retrotransposon markers were used to characterize this experimental population with genetic mapping, genetic map comparison and specific marker cloning analysis. Yield‐related traits were also recorded for identification of quantitative trait loci (QTLs). A remarkable range of novel genomic alterations was observed in the population, including simple sequence repeat (SSR) mutations, chromosomal rearrangements and retrotransposon activations. Most of these changes occurred immediately after interspecific hybridization, in the early stages of genome stabilization and derivation of experimental lines. These novel genomic alterations affected yield‐related traits in the introgressed <I>B.?napus</I> to an even greater extent than the alleles alone that were introgressed from the A<SUP>r</SUP> subgenome of <I>B.?rapa</I>, suggesting that genomic changes induced by interspecific hybridization are highly significant in both genome evolution and crop improvement.</P>

GaN nanorods gas sensor for highly sensitive n-butanol detection at room temperature

Shuai Han,Yongming Fu,Donghui Li,Dan Han,Qinjun Sun 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.3

Safe and effi cient detection of hazardous n-butanol gas is very great signifi cance to the health of workers and researchers inchemical environments. In this work, we successfully developed a GaN gas sensor by a simple solvothermal method and alow-temperature nitridation process. Material characterization results show that one-dimensional nanorods structures wereobtained and the products presented a superior growth orientation along with (101) plane. The gas sensing test results showthat the sensor exhibits excellent responsivity, repeatability, and selectivity to n-butanol at room temperature. The responseand recovery time of the sensor to 200 ppm n-butanol gas was 45 s/34 s. Gas adsorption model and electron depletion layertheory were established to understand the n-butanol sensing mechanism. This work provides the possibility for its realapplication in n-butanol detection with safe and effi cient at room temperature.

Renal-targeting peptide-microRNA nanocomplex for near IR imaging and therapy of renal ischemia/reperfusion injury

Yongtao Lin,Mingyue Zhao,Lin Bai,Hailun Li,Yong Xu,Xiang Li,Juan Xie,Yiyuan Zhang,Donghui Zheng 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

Renal ischemia-reperfusion injury (RI/R) is one of the main causes of acute renal injury and a commonclinical disease with high morbidity and mortality. It is of great significance to deliver microRNAs(miRNAs) to cells and in vivo to realize gene regulation and treatment of related diseases. In this study, wereported that the nanocomplex FMN-17 could realize both therapeutic and functional monitoringsimultaneously in vivo and in vitro. The nanocomplex comprised a cationic cell-penetrating peptidenona-arginine, a targeting ligand folic acid, a caspase-3 responsive moiety, and a Cy imaging moiety. Thenanocomplex FMN-17 has been shown to deliver miR-17-5p efficiently and selectively into HK-2 cells andtissues. Treatment of HK-2 cells with the nanocomplex significantly increased the miR-17-5p level andinhibited apoptosis, as evident by reducing the expression of active caspase-3 and reactive oxygenspecies. Uptake of FMN-17 in vivo alleviated renal tissue injury by histological assessment. In summary,we designed and synthesized a new miRNA delivery system with high transfection efficiency, goodtherapeutic effect, and near-infrared imaging in renal ischemia/reperfusion injury.

Characterization and evolutionary analysis of Brassica species-diverged sequences containing simple repeat units

Lijuan Wei,Meili Xiao,Annaliese S. Mason,Bi Ma,Kun Lu,Jia Na Li,Link Katrin,Donghui Fu 한국유전학회 2013 Genes & Genomics Vol.35 No.2

Brassica species, B. napus (canola), B. rapa and B. oleracea, are important sources of nutritionally valuable vegetable oil and protein-rich meal for animals and humans. Sequencing of the model plant Arabidopsis thaliana, has opened the way for investigations into the complex structure of the Brassica genomes, offering important insight into their evolution and composition. We use this sequence information for the characterization and functional analysis of SSR sequences that have diverged between the Brassica species. A total of 56 species-diverged sequences containing simple repeat units (SDS-SSR) of B. napus and its diploid progenitor species B. rapa and B. oleracea were isolated and characterized. Of these, 40 sequences showed homology with other Brassica sequences. Using the SSR Locator software, only 23 sequences were found to have SSRs,possibly due to the loss of SSR units in the process of species divergence. Sequence alignments with A. thaliana revealed that these species-diverged SSR sequences were responsible for Brassica divergence for differences between Brassica species in several genomic regions. Six active genes related to transferase, protein, transcription factor and retroelements were found in the SDS-SSRs. These results will further improve our understanding of the characteristics of species-diverged SSR fragments and their contribution to genome differentiation.