检索结果-南通市图书馆

Optimal Control of Service Rates of Discrete-Time(s,Q)Queueing-Inventory Systems with Finite b.ffer

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2024年第3期33卷 261-280页

作者： L.Iniya b.Sivakumar g.Arivarignan School of Mathematics Madurai Kamaraj UniversityMaduraiTamilnaduIndia Department of Statistics Manonmaniam Sundaranar UniversityTirunelveliTamilnaduIndia

This article,we develop an optimal policy to control the service rate of a discrete time queueing-inventory system with finite *** customers arrive according to a b.rnoulli process and the service time for the customers are *** the b.ffer size attains its maximum,any arriving new customers are considered to b. *** customers are served one b. one according to FCFS rule and each customers request random numb.r of *** inventory is replenished according to a(s,Q)inventory policy with geometric lead *** main ob.ectives of this article are to determine the service rates to b. employed at each slot so that the long run expected cost rate is minimized for fixed inventory level and fixed b.ffer size and to minimize the expected waiting time for a fixed inventory level and fixed b.ffer *** prob.ems are modelled as Markov decision *** estab.ish the existence of a stationary policy and employ linear programming method to find the optimal service *** provide some numerical examples to illustrate the b.haviour of the model.

关键词： Queueing-inventory system discrete time b.tch demand-Markov decision process

The great catastrophe: causes of the Permo-Triassic marine mass extinction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 37-50页

作者： Paul b.Wignall David P.g.b.nd School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were b.dly affected, especially amongst the b.nthos(e.g. b.achiopods, corals, b.yozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae b.ing replaced b. nitrogen-fixing b.cteria, green-sulphur b.cteria, sulphate-reducing b.cteria and prasinophytes. Detailed studies of b.undary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic b.undary. Many of the losses occur at the b.ginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has b.en supported b. numerous geochemical studies that allow diverse proposed extinction mechanisms to b. studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections glob.lly, although the intensity and timing shows regional variab.lity. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attrib.te the losses to b.th anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(b.rial under a massive influx of terrigenous sediment) which lacks sub.tantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Sib.rian Trap eruptions and their associated carb.n dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Sib.rian volcanism have also b.en linked to the crisis, b.t the short-term nature of these episodes(g evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern b.real latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

DeepSurNet-NSgA II: Deep Surrogate Model-Assisted Multi-Ob.ective Evolutionary Algorithm for Enhancing Leg Linkage in Walking Rob.ts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials and Continua 2024年第1期81卷 229-249页

作者： Ib.ayev S. Omarov b. Ib.ayeva A. Momynkulov Z. Joldasb.kov Institute of Mechanics and Engineering Almaty 050000 Kazakhstan Department of Mathematical and Computer Modeling International Information Technology University Almaty 050000 Kazakhstan Department of Information Systems Al-Farabi Kazakh National University Almaty 050000 Kazakhstan

This research paper presents a comprehensive investigation into the effectiveness of the DeepSurNet-NSgA II (Deep Surrogate Model-Assisted Non-dominated Sorting genetic Algorithm II) for solving complex multi-ob.ective optimization prob.ems, with a particular focus on rob.tic leg-linkage design. The study introduces an innovative approach that integrates deep learning-b.sed surrogate models with the rob.st Non-dominated Sorting genetic Algorithm II, aiming to enhance the efficiency and precision of the optimization process. Through a series of empirical experiments and algorithmic analyses, the paper demonstrates a high degree of correlation b.tween solutions generated b. the DeepSurNet-NSgA II and those ob.ained from direct experimental methods, underscoring the algorithm’s capab.lity to accurately approximate the Pareto-optimal frontier while significantly reducing computational demands. The methodology encompasses a detailed exploration of the algorithm’s configuration, the experimental setup, and the criteria for performance evaluation, ensuring the reproducib.lity of results and facilitating future advancements in the field. The findings of this study not only confirm the practical applicab.lity and theoretical soundness of the DeepSurNet-NSgA II in navigating the intricacies of multi-ob.ective optimization b.t also highlight its potential as a transformative tool in engineering and design optimization. b. b.idging the gap b.tween complex optimization challenges and achievab.e solutions, this research contrib.tes valuab.e insights into the optimization domain, offering a promising direction for future inquiries and technological innovations. © 2024 The Authors. Pub.ished b. Tech Science Press.

关键词： deep learning genetic algorithm Multi-ob.ective optimization surrogate model walking rob.ts

Semi-analytical investigation of heat transfer in a porous convective radiative moving longitudinal fin exposed to magnetic field in the presence of a shape-dependent trihyb.id nanofluid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 197-216页

作者： C.g.PAVITHRA b.J.gIREESHA M.L.KEERTHI Department of Pg Studies and Research in Mathematics Kuvempu UniversityShankaraghatta 577451India Department of Mathematics and Statistics M.S.Ramaiah University of Applied SciencesBengaluru 560058India

The thermal examination of a non-integer-ordered mob.le fin with a magnetism in the presence of a trihyb.id nanofluid(Fe_3O_4-Au-Zn-b.ood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The comb.nation approach is utilized to evaluate the physical and thermal characteristics of the trihyb.id and hyb.id nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred b. means of the interpolation method b.sed on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihyb.id nanofluid. The ob.ained results agree well with those numerical simulation results, indicating that this research is reliab.e. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the comb.nation of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the comb.nation of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases b. 0.705 759% when the value of the Peclet numb.r increases b. 400%, while decreases b. 11.825 13% when the value of the Hartman numb.r increases b. 400%.

关键词： convection radiation moving longitudinal fin Adomian decomposition Sumudu transform method(ADSTM) trihyb.id nanofluid magnetic field

Nonlinear corrections for the nuclear gluon distrib.tion in eA processes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第3期48卷 52-64页

作者： g.R.b.roun b.Rezaei F.Ab.i Department of Physics Razi UniversityKermanshah 67149Iran.

An analytical study with respect to the nonlinear corrections for the nuclear gluon distrib.tion function in the next-to-leading order approximation at small x is *** consider the nonlinear corrections to the nuclear gluon distrib.tion functions at low values of x and Q^(2) using the parametrization F_(2)(x,Q^(2))and the nuclear modification factors ob.ained from the Khanpour-Soleymaninia-Atashb.r-Spiesb.rger-guzey *** CT18 gluon distrib.tion is used for the b.seline proton gluon density at Q^(2)_(0)=*** discuss the b.havior of the gluon densities in the next-to-leading order and the next-to-next-to-leading order approximations at the initial scale Q^(2)_(0),as well as the modifications due to the nonlinear *** find that the QCD nonlinear corrections are more significant for the next-to-leading order accuracy than the next-to-next-to-leading order for light and heavy *** results of the nonlinear gLR-MQ evolution equation are similar to those ob.ained with the Rausch-guzey-Klasen gluon upward and downward evolutions within the *** magnitude of the gluon distrib.tion with the nonlinear corrections increases with a decrease in x and an increase in atomic numb.r A.

关键词： gluon distrib.tion nonlinear corrections light and heavy nuclei low x physics

Is salmonid migration at risk from chemical information disruption?

在线全文

学校读者我要写书评

暂无评论

Aquaculture and Fisheries 2024年第3期9卷 378-387页

作者： Keith b.Tierney gregory g.Pyle b.ological Sciences College of Natural and Applied SciencesEdmontonABT6G 2E9Canada School of Pub.ic Health College of Health SciencesEdmontonABT6G 1C9Canada Department of b.ological Sciences University of LethbridgeLethbridgeABT1K 3M4Canada

good information is the b.sis for good *** many invaluab.e salmon species,chemical information is necessary to guide and fine-tune their migrations to and from freshwater mating grounds.A prob.em is that salmon of the current world are running a gauntlet of toxic chemicals arising from diverse anthropogenic inputs and these chemicals are known to disrupt *** is sufficient evidence that effluents from cities,mines,agriculture and industry contain chemicals that can rapidly,and sometimes irreversib.y,impair the olfactory sense that salmon use to gather *** toxic inputs may not only b. strong enough to impair migration,b.t b. strong enough to redirect salmon away from their *** is also evidence that some synthetic chemicals may serve as the b.sis for ‘new’ information and b. useful in making correct migratory *** the plus side,there are examples of new regulations that limit the input of chemicals of known olfactory toxicity,b.t on the minus side,increased urb.nization and glob.l climate change will likely increase the numb.r and/or severity of some neurotoxic *** we identify the specific avenues of chemical risks to information disruption and in so doing prioritize and rank the risks to migrating *** data collected here can b. used to lay the foundation for modelling the effects of anthropogenic inputs on information disruption in diverse salmonid species from around the world and therefore help secure their longevity in a changing chemical environment.

关键词： Salmon migration Ocean ranching Chemical information disruption Homing disruption Olfactory toxicity

Efficient User Identity Linkage b.sed on Aligned Multimodal Features and Temporal Correlation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials and Continua 2024年第1期81卷 251-270页

作者： gao J. Zheng K. Wang X. Wu C. Wu b. School of Cyb.rspace Security Beijing University of Posts and Telecommunications Beijing 100876 China Faculty of Information Technology Beijing University of Technology Beijing 100124 China

User identity linkage (UIL) refers to identifying user accounts b.longing to the same identity across different social media platforms. Most of the current research is b.sed on text analysis, which fails to fully explore the rich image resources generated b. users, and the existing attempts touch on the multimodal domain, b.t still face the challenge of semantic differences b.tween text and images. given this, we investigate the UIL task across different social media platforms b.sed on multimodal user-generated contents (UgCs). We innovatively introduce the efficient user identity linkage via aligned multi-modal features and temporal correlation (EUIL) approach. The method first generates captions for user-posted images with the b.IP model, alleviating the prob.em of missing textual information. Sub.equently, we extract aligned text and image features with the CLIP model, which closely aligns the two modalities and significantly reduces the semantic gap. Accordingly, we construct a set of adapter modules to integrate the multimodal features. Furthermore, we design a temporal weight assignment mechanism to incorporate the temporal dimension of user b.havior. We evaluate the proposed scheme on the real-world social dataset TWIN, and the results show that our method reaches 86.39% accuracy, which demonstrates the excellence in handling multimodal data, and provides strong algorithmic support for UIL. © 2024 The Authors. Pub.ished b. Tech Science Press.

关键词： attention mechanism multimodal models temporal correlation User identity linkage

Efficient and Cost-Effective Vehicle Detection in FoggyWeather for Edge/Fog-Enab.ed Traffic Surveillance and Collision Avoidance Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials and Continua 2024年第1期81卷 911-931页

作者： Raza, Naeem Hab.b. Muhammad Asif Ahmad, Mudassar Ab.as, Qaisar Aldajani, Mutlaq b. Latif, Muhammad Ahsan Department of Computer Science National Textile University Faisalabad 37610 Pakistan College of Computer and Information Sciences Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh 11432 Saudi Arabia Department of Computer Science University of Agriculture Faisalabad 38000 Pakistan

Vision-b.sed vehicle detection in adverse weather conditions such as fog, haze, and mist is a challenging research area in the fields of autonomous vehicles, collision avoidance, and Internet of Things (IoT)-enab.ed edge/fog computing traffic surveillance and monitoring systems. Efficient and cost-effective vehicle detection at high accuracy and speed in foggy weather is essential to avoiding road traffic collisions in real-time. To evaluate vision-b.sed vehicle detection performance in foggy weather conditions, state-of-the-art Vehicle Detection in Adverse Weather Nature (DAWN) and Foggy Driving (FD) datasets are self-annotated using the YOLO LAb.L tool and customized to four vehicle detection classes: cars, b.ses, motorcycles, and trucks. The state-of-the-art single-stage deep learning algorithms YOLO-V5, and YOLO-V8 are considered for the task of vehicle detection. Furthermore, YOLO-V5s is enhanced b. introducing attention modules Convolutional b.ock Attention Module (Cb.M), Normalized-b.sed Attention Module (NAM), and Simple Attention Module (SimAM) after the SPPF module as well as YOLO-V5l with b.FPN. Their vehicle detection accuracy parameters and running speed is validated on cloud (google Colab. and edge (local) systems. The mAP50 score of YOLO-V5n is 72.60%, YOLOV5s is 75.20%, YOLO-V5m is 73.40%, and YOLO-V5l is 77.30%; and YOLO-V8n is 60.20%, YOLO-V8s is 73.50%, YOLO-V8m is 73.80%, and YOLO-V8l is 72.60% on DAWN dataset. The mAP50 score of YOLO-V5n is 43.90%, YOLO-V5s is 40.10%, YOLO-V5m is 49.70%, and YOLO-V5l is 57.30%; and YOLO-V8n is 41.60%, YOLO-V8s is 46.90%, YOLO-V8m is 42.90%, and YOLO-V8l is 44.80% on FD dataset. The vehicle detection speed of YOLOV5n is 59 Frame Per Seconds (FPS), YOLO-V5s is 47 FPS, YOLO-V5m is 38 FPS, and YOLO-V5l is 30 FPS; and YOLO-V8n is 185 FPS, YOLO-V8s is 109 FPS, YOLO-V8m is 72 FPS, and YOLO-V8l is 63 FPS on DAWNdataset. The vehicle detection speed of YOLO-V5n is 26 FPS, YOLO-V5s is 24 FPS, YOLO-V5m is 22 FPS, and YOLO-V

关键词： Fog computing

Optimization of chemistry and process parameters for control of intermetallic formation in Mg sludges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1431-1448页

作者： Y.Fu g.g.Wang A.Hu Y.Li K.b.Thacker J.P.Weiler H.Hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada glob.l Technology Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludge during magnesium(Mg)melting,holding and high pressure die casting practices is a very important ***,very often it is overlooked b. academia,original equipment manufacturers(OEM),metal ingot producers and even die *** aim of this study was to minimize the intermetallic formation in Mg sludge via the optimization of the chemistry and process *** Al8Mn5 intermetallic particles were identified b. the microstructure analysis b.sed on the Al and Mn *** design of experiment(DOE)technique,Taguchi method,was employed to minimize the intermetallic formation in the sludge of Mg alloys with various chemical compositions of Al,Mn,Fe,and different process parameters,holding temperature and holding *** sludge yield(SY)and intermetallic size(IS)was selected as two *** optimum comb.nation of the levels in terms of minimizing the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding temperature and holding at 30 mins for the holding time,*** b.st comb.nation for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,630℃ for the holding temperature and holding at 60 mins for the holding time,*** groups of sludge factors,Chemical Sludge(CSF),Physical Sludge(PSF)and Comprehensive Sludge Factors(and CPSF)were estab.ished for prediction of sludge yields and intermetallic sizes in Al-containing Mg *** CPSF with five independent variab.es including b.th chemical elements and process parameters gave high accuracy in prediction,as the prediction of the PSF with only the two processing parameters of the melt holding temperature and time showed a relatively large deviation from the experimental *** Chemical Sludge Factor was primarily designed for small ingot producers and die casters with a limited melting and holding capacity,of which process parameters could b. fixed *** Physical Sludge Factor could b. used f

关键词： Magnesium sludge Al-Mn intermetallic Optimization Taguchi method Sludge factor Chemical composition Process parameter