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Direct-to-indirect mapping for optimal low-thrust trajectories

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Astrodynamics 2024年第1期8卷 27-46页

作者： David Ottesen Ryan P.russell Department of Aerospace Engineering and Engineering Mechanics The University of Texas at AustinAustinTexas78712USA

Optimal,many-revolution spacecraft trajectories are challenging to solve.A connection is made for a class of models between optimal direct and indirect *** transfers that minimize thrust-acceleration-squared,primer vector theory maps direct,many-impulsive-maneuver trajectories to the indirect,continuous-thrust-acceleration *** mapping algorithm is independent of how the direct solution is obtained and requires only a solver for a boundary value problem and its partial derivatives.A Lambert solver is used for the two-body problem in this *** mapping is simple because the impulsive maneuvers and co-states share the same linear space around an optimal *** numerical results,the direct coast-impulse solutions are demonstrated to converge to the indirect continuous solutions as the number of impulses and segments *** two-body design space is explored with a set of three many-revolution,many-segment examples changing semimajor axis,eccentricity,and *** first two examples involve a small change to either semimajor axis or eccentricity,and the third example is a transfer to geosynchronous *** a single processor,the optimization runtime is seconds to minutes for revolution counts of 10 to 100,and on the order of one hour for examples with up to 500 *** of these thrust-acceleration-squared solutions are good candidates to start a homotopy to a higher-fidelity minimization problem with practical constraints.

关键词： direct optimization indirect optimization impulsive maneuvers Lambert's problem two-body dynamics primer vectortheory

knowledge and discriminatory attitudes towards HIV/AIDS among the women of reproductive age group of Pakistan using the Multiple Indicator Cluster Survey(MICS)

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Global Health Journal 2024年第2期8卷 74-82页

作者： Remsha Hussain russell kabir School of Allied Health Faculty of HealthMedicine and Social CareAnglia Ruskin UniversityUnited Kingdom

Background Human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)has become a major worldwide public health issue,with a focus on developing *** having a very low HIV prevalence,South Asia faces serious issues with stigma and false information because of a lack of *** stigma highlights significant gaps in popular awareness while also sustaining unfavorable attitudes towards those living with HIV/*** is ranked second in South Asia for the rapidly increasing AIDS *** information and optimistic outlooks are essential for successful HIV/AIDS prevention,control,and *** false beliefs about how HIV/AIDS spreads lead to negative perceptions,which highlights the need to look into how women’s knowledge and attitudes about HIV/AIDS in Pakistan are influenced by sociodemographic traits and *** The purpose of this study is to evaluate Pakistani women’s discriminatory attitudes and level of awareness on HIV/*** study used data(the women in reproductive age 15-49 years’dataset)from the Pakistan Multiple Indicator Cluster Survey to conduct an analytical cross-sectional *** represent the respondents’attitudes and knowledge towards people living with HIV(PLHIV),two composite variables were developed and composite *** logistics regression was used to identify predictor variables and chi-square was used for bivariate *** The findings reveal that almost 90%of Pakistani women have poor knowledge and attitude with HIV/*** Punjab,72.8%of rural residents have low knowledge,whereas only 20.6%of young individuals(15-khyber Pakhtunkhwa typically have more *** of HIV is positively correlated with education;those with higher education levels know a lot more(odds ratio[OR]=5.419).Similarly,quintil

关键词： HIV/AIDS PLHIV knowledge Attitudes Women Pakistan

RecBERT:Semantic recommendation engine with large language model enhanced query segmentation for k-nearest neighbors ranking retrieval

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Intelligent and Converged Networks 2024年第1期5卷 42-52页

作者： richard Wu the Dublin Unified School District and the SF Artificial Intelligence Club DublinCA 94568USA

The increasing amount of user traffic on Internet discussion forums has led to a huge amount of unstructured natural language data in the form of user *** modern recommendation systems rely on manual tagging,relying on administrators to label the features of a class,or story,which a user comment corresponds *** common approach is to use pre-trained word embeddings to compare class descriptions for textual similarity,then use a distance metric such as cosine similarity or Euclidean distance to find top k ***,neither approach is able to fully utilize this user-generated unstructured natural language data,reducing the scope of these recommendation *** paper studies the application of domain adaptation on a transformer for the set of user comments to be indexed,and the use of simple contrastive learning for the sentence transformer fine-tuning process to generate meaningful semantic embeddings for the various user comments that apply to each *** order to match a query containing content from multiple user comments belonging to the same class,the construction of a subquery channel for computing class-level similarity is *** channel uses query segmentation of the aggregate query into subqueries,performing k-nearest neighbors(kNN)search on each individual *** achieves state-of-the-art performance,outperforming other state-of-the-art models in accuracy,precision,recall,and F1 score for classifying comments between four and eight classes,*** outperforms the most precise state-of-the-art model(distilRoBERTa)in precision by 6.97%for matching comments between eight classes.

关键词： sentence transformer simple contrastive learning large language models query segmentation k-nearest neighbors

Bound and Resonating Multiquark Configurations

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Chinese Physics Letters 2024年第8期41卷 8-12页

作者： Jean-Marc richard Institut de Physique des 2 Infinis de Lyon Université Claude Bernard(Lyon 1) CNRS-IN2P34 rue Enrico Fermi69622 VilleurbanneFrance

We review the predictions of quark models for multiquark configurations that are bound or resonant states,and compare different methods for estimating the properties of resonances.

关键词： quark Configuration resonant

Parameter-Free Shifted Laplacian Reconstruction for Multiple kernel Clustering

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1072-1074页

作者： Xi Wu Zhenwen Ren F.richard Yu the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010China the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010 the Guangxi key Laboratory of Machine Vision and Intelligent Control Wuzhou UniversityWuzhou 543002 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen 518060China

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MkC)method by using shifted Laplacian *** MkC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

关键词： parameter letter Parameter

Pelvic fractures in blunt trauma patients:A comparative study

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World Journal of Orthopedics 2024年第5期15卷 418-434页

作者： Alexander A Fokin Joanna Wycech knight Madison E Tharp kyler C Brinton Phoebe k Gallagher Justin Fengyuan Xie russell D Weisz Ivan Puente Trauma and Critical Care Services Delray Medical CenterDelray BeachFL 33484United States Charles E Schmidt College of Medicine Department of SurgeryFlorida Atlantic UniversityBoca RatonFL 33431United States Trauma and Critical Care Services Broward Health Medical CenterFort LauderdaleFL 33316United States Charles E Schmidt College of Medicine Florida Atlantic UniversityBoca RatonFL 33431United States Herbert Wertheim College of Medicine Department of SurgeryFlorida International UniversityMiamiFL 33199United States

BACkGROUND Pelvic fractures(PF)with concomitant injuries are on the rise due to an increase of high-energy *** of the elderly population with age related comorbidities further complicates the *** organ injuries are kindred with PF due to the proximity to pelvic *** of contrast blush(CB)on computed tomography in patients with PF is considered a sign of active bleeding,however,its clinical significance and association with outcomes is *** To analyze polytrauma patients with PF with a focus on the geriatric population,co-injuries and the value of contrast *** This retrospective cohort study included 558 patients with PF admitted to level 1 trauma center(01/2017-01/2023).Analyzed variables included:Age,sex,mechanism of injury(MOI),injury severity score(ISS),Glasgow coma scale(GCS),abbreviated injury scale(AIS),co-injuries,transfusion requirements,pelvic angiography,embolization,laparotomy,orthopedic pelvic surgery,intensive care unit and hospital lengths of stay,discharge disposition and *** study compared geriatric and non-geriatric patients,patients with and without CB and abdominal *** score matching was implemented in comparison *** PF comprised 4%of all trauma admissions.89 patients had CB.286(52%)patients had concomitant injuries including 93(17%)patients with abdominal *** patients compared to non-geriatric had more falls as MOI,lower ISS and AIS pelvis,higher GCS,less abdominal co-injuries,similar CB and angio-embolization rates,less orthopedic pelvic surgeries,shorter lengths of stay and higher *** propensity matching,orthopedic pelvic surgery rates remained lower(8%vs 19%,P<0.001),hospital length of stay shorter,and mortality higher(13%vs 4%,P<0.001)in geriatric *** of 89 patients with CB,45(51%)were *** propensity matching,patients with CB compared to without CB had more pelvic angiography(71%vs 12%,P<0.001),hi

关键词： Pelvic fractures Geriatric trauma patients Abdominal co-injuries Contrast blush Contrast extravasation Angioembolization Polytrauma patients Surgical interventions Blunt trauma External and internal fixation for pelvic stabilization

Liver transplantation as an alternative for the treatment of non-resectable liver colorectal cancer: Advancing the therapeutic algorithm

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 154-159页

作者： Badi Rawashdeh richard Bell Abdul Hakeem Raj Prasad Division of Transplant Surgery Department of General SurgeryMedical College of WisconsinMilwaukeeWI53226USA Leeds Teaching Hospital LeedsUK

Colorectal cancer is a leading cause of cancerrelated mortality,with nearly half of the affected patients developing liver *** three decades,liver resection(LR)has been the primary curative strategy,yet its applicability is limited to about 20%of *** transplantation(LT)for unresectable metastases was attempted unsuccessfully in the 1990s,with high rates of perioperative death and *** is now more interest in this strategy due to improvements in systemic therapies and surgical techniques.A significant study conducted by the Oslo group showed that patients receiving liver transplants had a 60%chance of survival after five *** better results have been achieved by using advanced imaging for risk stratification and further refining selection criteria,especially in the Norvegian SECA *** review carefully charts the development and history of LT as a treatment option for colorectal cancer liver *** revolutionary path from the early days of exploratory surgery to the current situation of cautious optimism is traced,highlighting the critical clinical developments and improved patient selection standards that have made LT a potentially curative treatment for such challenging very well selected cases.

关键词： Liver transplantation Colorectal cancer liver metastases Non-resectable liver metastases

ARCADE 2 Spatial Roar, What Theory of Relation Reveals

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Journal of Modern Physics 2024年第5期15卷 690-719页

作者： russell Bagdoo Saint-Bruno-de-Montarville Quebec Canada

The theory of Relation provides an explanation for the Arcade 2 excess. It assumes that the isotropic radio emission measured by the Arcade 2 Collaboration, which is 5 - 6 times brighter than the expected contributions from known extra-galactic sources, is the residue of an immense primitive energy of ordinary matter released by a relativistic bang almost 100 million years after the big bang, which gave the mass-energy the missing gravity to activate contraction. This relativistic bang, via a Lorentz energy transformation, would have released enormous energy held to be the source of the powerful radio noise detected by the NASA researchers. This transformation would have simultaneously triggered the formation of the first stars from dense gas and the reionization of less dense neutral gas. This departs from the idea that continuous reionization began after the formation of the first stars. We emphasize the importance of primordial magnetic fields, which would have generated significant density fluctuations during recombination and acted as a direct seed for cosmic structures. The first stars and galaxies were bathed in strong magnetic fields that gave rise to the radio microwave din (boom) discovered by Arcade 2. These intense magnetic fields alter the trajectory of charged particles zooming near the speed of light, triggering the space roar and emitting radiation that forms a synchrotron radio background. The theory of Relation offers an alternative to the Lambda-CDM cosmological model, which has become the standard model of the big bang, which leads straight to the vacuum catastrophe.

关键词： Arcade 2 Excess Relativistic Bang Theory of Relation Lorentz Energy Transformation Cosmic Statics Cosmic Boom Synchrotron Radio Background Primordial Magnetic Fields

New analytical modelling of fractional generalized kuramoto-Sivashinky equation via Atangana-Baleanu operator and J-transform method

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Journal of Ocean Engineering and Science 2024年第1期9卷 66-88页

作者： Metonou richard Weidong Zhao Shehu Maitama School of Mathematics Shandong UniversityJinanShandongChina

In this paper,we propose a new analytical modelling of the well-known fractional generalized kuramoto-Sivashinky equation(FGkSE)using fractional operator with non-singular kernel and the homotopy anal-ysis transform method via J-transform ***,using fixed-point theorem,we prove the existence and uniqueness of our proposed solution to the fractional kuramoto-Sivashinky *** further val-idate the efficiency of the suggested technique,we proved the convergence analysis of the method and provide the error *** obtained solutions of the FGkSE,describing turbulence processes in the field of ocean engineering are analytically and numerically compared to show the behaviors of many parameters of the present model.

关键词： Homotopy analysis J-transform method J-transform method Fractional generalized kuramoto-Sivashinky equation Fixed-point theorem Numeric-symbolic computation