Leveraging Multimodal Features and Item-level User Feedback for Bundle Construction

Automatic bundle construction is a crucial prerequisite step in various bundle-aware online services. Previous approaches are mostly designed to model the bundling strategy of existing bundles. However, it is hard to acquire large-scale well-curated bundle dataset, especially for those platforms that have not offered bundle services before. Even for platforms with mature bundle services, there are still many items that are included in few or even zero bundles, which give rise to sparsity and cold-start challenges in the bundle construction models. To tackle these issues, we target at leveraging multimodal features, item-level user feedback signals, and the bundle composition information, to achieve a comprehensive formulation of bundle construction. Nevertheless, such formulation poses two new technical challenges: 1) how to learn effective representations by optimally unifying multiple features, and 2) how to address the problems of modality missing, noise, and sparsity problems induced by the incomplete query bundles. In this work, to address these technical challenges, we propose a Contrastive Learning-enhanced Hierarchical Encoder method (CLHE). Specifically, we use self-attention modules to combine the multimodal and multi-item features, and then leverage both item- and bundle-level contrastive learning to enhance the representation learning, thus to counter the modality missing, noise, and sparsity problems. Extensive experiments on four datasets in two application domains demonstrate that our method outperforms a list of SOTA methods. The code and dataset are available at https://github.com/Xiaohao-Liu/CLHE

Ground Calibration Result of the Lobster Eye Imager for Astronomy

We report on results of the on-ground X-ray calibration of the Lobster Eye Imager for Astronomy (LEIA), an experimental space wide-field (18.6*18.6 square degrees) X-ray telescope built from novel lobster eye mirco-pore optics. LEIA was successfully launched on July 27, 2022 onboard the SATech-01 satellite. To achieve full characterisation of its performance before launch, a series of tests and calibrations have been carried out at different levels of devices, assemblies and the complete module. In this paper, we present the results of the end-to-end calibration campaign of the complete module carried out at the 100-m X-ray Test Facility at IHEP. The PSF, effective area and energy response of the detectors were measured in a wide range of incident directions at several X-ray line energies. The distributions of the PSF and effective areas are roughly uniform across the FoV, in large agreement with the prediction of lobster-eye optics. The mild variations and deviations from the prediction of idealized lobster-eye optics can be understood to be caused by the imperfect shapes and alignment of the micro-pores as well as the obscuration by the supporting frames, which can be well reproduced by MC simulations. The spatial resolution of LEIA defined by the FWHM of the focal spot ranges from 4-8 arcmin with a median of 5.7. The measured effective areas are in range of 2-3 $cm^2$ at ~1.25 keV across the entire FoV, and its dependence on photon energy is in large agreement with simulations. The gains of the CMOS sensors are in range of 6.5-6.9 eV/DN, and the energy resolutions in the range of ~120-140 eV at 1.25 keV and ~170-190 eV at 4.5 keV. These results have been ingested into the calibration database and applied to the analysis of the scientific data acquired by LEIA. This work paves the way for the calibration of the Wide-field X-Ray Telescope modules of the Einstein Probe mission.Comment: 24 pages, 13 figures. Submitted to Experimental Astronom

The Large Hadron-Electron Collider at the HL-LHC

The Large Hadron-Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton-nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron-hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.Peer reviewe

Dynamics Analysis of the Double Motors Synchronously Exciting Nonlinear Vibration Machine Based on Acceleration Sensor Signal

Using the equivalent linearization method, the compensation and influence of the main vibration spring stiffness to the movement stability of the nonlinear resonance machine which synchronously driven by double exciting motors have been discussed. And using the singular perturbation theory, the influence of the nonlinear force which caused by load fluctuate to the stability of the vibration machine have been researched also. By the experiment and the actual production application, the validity of the mechanical motion stability analysis conclusion for the double motors synchronously exciting nonlinear vibration machine has been verified. The research conclusions that carried out in the paper have important reference value for the dynamic analysis and practical debugging of the double motors synchronously exciting nonlinear vibration machine

Disciplinary enculturation and authorial stance: Comparison of stance features among master’s dissertations, doctoral theses, and research articles

Achieving a credible and authoritative stance in academic writing requires a writer’s disciplinary enculturation. While postgraduate students may have a foot in the door, expert writers have accumulated much knowledge and practice in their research fields. However, we do not yet know enough about how writers with different degrees of disciplinary enculturation produce an authorial stance in specific writing contexts. To address this gap, this study explores the use of stance features in master’s dissertations, doctoral theses, and published research articles in applied linguistics. Findings show that master’s students employed more hedges, boosters, and attitude markers, but fewer self-mentions than doctoral and expert writers, suggesting they were tentative in making propositions and respectful of claims in their disciplinary community. Doctoral candidates adopted similar stance expression practices as expert writers, indicating their emergent mastery of their field’s rhetorical conventions. The findings contribute to understandings of writers’ differences in taking authorial stance with respect to disciplinary enculturation, and suggest ways to enhance postgraduate students’ stance-taking practices in academic writingPara mostrar credibilidad y autoridad, los autores de textos académicos deben adquirir los usos y hábitos de sus respectivas disciplinas. Mientras los estudiantes de posgrado todavía están iniciándose, los investigadores experimentados ya han acumulado muchos conocimientos y práctica en sus áreas de investigación. Se sabe poco, sin embargo, sobre el modo en que los distintos grados de enculturación académica afectan al posicionamiento del autor en contextos concretos de escritura. Para averiguarlo, en el presente estudio se examinan las distintas estrategias de posicionamiento del autor utilizadas en tesis de máster y de doctorado y en artículos de investigación de expertos publicados en el campo de la lingüística aplicada. Los resultados muestran que los estudiantes de posgrado utilizan más mitigadores, intensificadores y marcadores de actitud, pero no se mencionan a sí mismos tanto como los doctorandos o los escritores expertos, lo cual indica que los estudiantes de posgrado son prudentes en sus afirmaciones y respetuosos de los preceptos de su comunidad disciplinar. En los doctorandos se aprecia una práctica similar a la de los escritores expertos a la hora de manifestar su postura, lo que indica un cierto dominio incipiente de la retórica de la disciplina. Los hallazgos de esta investigación ayudan a comprender las diferencias en la adopción de un determinado posicionamiento por parte de diversos grupos de escritores en relación con su enculturación académica e inspiran fórmulas de mejora de las prácticas habituales entre los estudiantes de posgrad

Chinese EAP teachers’ graduate-level English academic writing instruction and their professional development

In China, it has been widely recognized that graduate students urgently need to develop capabilities in engaging in academic communication at the international level, above all through writing and publishing their research in English. This educational need has stimulated the growth of EAP and the teaching of English academic writing (EAW) to graduate students across disciplines at Chinese universities. In this paper we report an interview-based study which focused on understanding Chinese emerging EAP teachers’ graduate-level EAW instruction and their endeavors of professional development (PD). Our study adds to the limited existing literature on EAP practitioners’ contextualized teaching practices and their professional development, and generates insights that can be drawn upon by EAP professionals in other contextsEn China está ampliamente reconocida la urgente necesidad que tienen los estudiantes de posgrado de desarrollar capacidades de comunicación académica a nivel internacional, sobre todo por medio de la redacción y publicación de su investigación en inglés. Esta necesidad educativa ha alentado el auge del inglés para fines académicos y de la enseñanza de la escritura académica en inglés para estudiantes de posgrado de multitud de disciplinas en las universidades chinas. En este artículo ofrecemos los resultados de un estudio basado en una serie de entrevistas que trata de comprender cómo se produce la instrucción de la escritura académica en inglés en el nivel de posgrado llevada a cabo por profesores chinos noveles en la enseñanza del inglés para fines académicos y cuáles son los esfuerzos que realizan en su desarrollo profesional. Nuestro estudio ofrece una aportación a la escasa bibliografía acerca de las prácticas docentes contextualizadas de los profesionales de inglés para fines académicos y de su desarrollo profesional y ofrece conocimientos de los que pueden servirse los profesionales del inglés para fines académicos en otros contexto

Levitation Stability and Hopf Bifurcation of EMS Maglev Trains

This paper analyzed the mechanical characteristics of single electromagnet system and elastic track beam of EMS maglev train and established a five-dimensional dynamics model of single electromagnet-track beam coupled system with classical PD control strategy adopted for its levitation system. Then, based on the Hurwitz criterion and the high-dimensional Hopf bifurcation theory, the stability of the coupled system is analyzed; the existence of the Hopf bifurcation is discussed and the bifurcation direction and the stability of the periodic solution are determined with levitation control feedback coefficient kp as the bifurcation parameter; and numerical simulation is conducted to verify the validity of the theoretical analysis results. The results show that the Hurwitz algebra criterion can directly determine the eigenvalues and symbols of the dynamics system to facilitate the analysis on the stability of the system and the Hopf bifurcation without the necessity of calculating the specific eigenvalues; supercritical Hopf bifurcation will occur under the given parameters, that is, when kp<kp0, the real-time system is asymptotically stable, yet Hopf bifurcation occurs as kp increases gradually beyond kp0, with the stability of the system lost and a stable limit cycle branched