135 research outputs found
Brand marketing strategy (taking Xiaomi as an example)
This article mainly talks about Xiaomi's marketing strategy, including products, promotions, pricing, brand marketing offerings, emphasis on product innovation, and smart use of hungry marketing. This successful case can serve as an example for other brands and help them do better marketing and brand promotion
High order computation of optimal transport, mean field planning, and mean field games
Mean-field games (MFGs) have shown strong modeling capabilities for large
systems in various fields, driving growth in computational methods for
mean-field game problems. However, high order methods have not been thoroughly
investigated. In this work, we explore applying general high-order numerical
schemes with finite element methods in the space-time domain for computing the
optimal transport (OT), mean-field planning (MFP), and MFG problems. We conduct
several experiments to validate the convergence rate of the high order method
numerically. Those numerical experiments also demonstrate the efficiency and
effectiveness of our approach
A primal-dual approach for solving conservation laws with implicit in time approximations
In this work, we propose a novel framework for the numerical solution of
time-dependent conservation laws with implicit schemes via primal-dual hybrid
gradient methods. We solve an initial value problem (IVP) for the partial
differential equation (PDE) by casting it as a saddle point of a min-max
problem and using iterative optimization methods to find the saddle point. Our
approach is flexible with the choice of both time and spatial discretization
schemes. It benefits from the implicit structure and gains large regions of
stability, and overcomes the restriction on the mesh size in time by explicit
schemes from Courant--Friedrichs--Lewy (CFL) conditions (really via von Neumann
stability analysis). Nevertheless, it is highly parallelizable and
easy-to-implement. In particular, no nonlinear inversions are required!
Specifically, we illustrate our approach using the finite difference scheme and
discontinuous Galerkin method for the spatial scheme; backward Euler and
backward differentiation formulas for implicit discretization in time.
Numerical experiments illustrate the effectiveness and robustness of the
approach. In future work, we will demonstrate that our idea of replacing an
initial-value evolution equation with this primal-dual hybrid gradient approach
has great advantages in many other situations
What Makes for Robust Multi-Modal Models in the Face of Missing Modalities?
With the growing success of multi-modal learning, research on the robustness
of multi-modal models, especially when facing situations with missing
modalities, is receiving increased attention. Nevertheless, previous studies in
this domain exhibit certain limitations, as they often lack theoretical
insights or their methodologies are tied to specific network architectures or
modalities. We model the scenarios of multi-modal models encountering missing
modalities from an information-theoretic perspective and illustrate that the
performance ceiling in such scenarios can be approached by efficiently
utilizing the information inherent in non-missing modalities. In practice,
there are two key aspects: (1) The encoder should be able to extract
sufficiently good features from the non-missing modality; (2) The extracted
features should be robust enough not to be influenced by noise during the
fusion process across modalities. To this end, we introduce Uni-Modal Ensemble
with Missing Modality Adaptation (UME-MMA). UME-MMA employs uni-modal
pre-trained weights for the multi-modal model to enhance feature extraction and
utilizes missing modality data augmentation techniques to better adapt to
situations with missing modalities. Apart from that, UME-MMA, built on a
late-fusion learning framework, allows for the plug-and-play use of various
encoders, making it suitable for a wide range of modalities and enabling
seamless integration of large-scale pre-trained encoders to further enhance
performance. And we demonstrate UME-MMA's effectiveness in audio-visual
datasets~(e.g., AV-MNIST, Kinetics-Sound, AVE) and vision-language
datasets~(e.g., MM-IMDB, UPMC Food101)
Metabolic Engineering to Improve Docosahexaenoic Acid Production in Marine Protist Aurantiochytrium sp. by Disrupting 2,4-Dienoyl-CoA Reductase
Docosahexaenoic acid (DHA) has attracted attention from researchers because of its pharmacological and nutritional importance. Currently, DHA production costs are high due to fermentation inefficiency; however, improving DHA yield by metabolic engineering in thraustochytrids is one approach to reduce these costs. In this study, a high-yielding (53.97% of total fatty acids) DHA production strain was constructed by disrupting polyunsaturated fatty acid beta-oxidation via knockout of the 2,4-dienyl-CoA reductase (DECR) gene (KO strain) in Aurantiochytrium sp. Slight differences in cell growth was observed in the wild-type and transformants (OE and KO), with cell concentrations in stationary of 2.65×106, 2.36×106 and 2.56×106 cells mL-1 respectively. Impressively, the KO strain yielded 21.62% more neutral lipids and 57.34% greater DHA production; moreover, the opposite was observed when overexpressing DECR (OE strain), with significant decreases of 30.49% and 64.61%, respectively. Furthermore, the KO strain showed a prolonged DHA production period with a sustainable increase from 63 to 90 h (170.03 to 203.27 mg g−1 DCW), while that of the wildtype strain decreased significantly from 150.58 to 140.10 mg g−1 DCW. This new approach provides an advanced proxy for the construction of sustainable DHA production strains for industrial purposes and deepens our understanding of the metabolic pathways of Aurantiochytrium sp
Combination of MRO SHARAD and deep-learning-based DTM to search for subsurface features in Oxia Planum, Mars
Context. Oxia Planum is a mid-latitude region on Mars that attracts a great amount of interest worldwide. An orbiting radar provides an effective way to probe the Martian subsurface and detect buried layers or geomorphological features. The Shallow radar orbital radar system on board the NASA Mars reconnaissance orbiter transmits pulsed signals towards the nadir and receives returned echoes from dielectric boundaries. However, radar clutter can be induced by a higher topography of the off-nadir region than that at the nadir, which is then manifested as subsurface reflectors in the radar image.
Aims. This study combines radar observations, terrain models, and surface images to investigate the subsurface features of the ExoMars landing site in Oxia Planum.
Methods. Possible subsurface features are observed in radargrams. Radar clutter is simulated using the terrain models, and these are then compared to radar observations to exclude clutter and identify possible subsurface return echoes. Finally, the dielectric constant is estimated with measurements in both radargrams and surface imagery.
Results. The resolution and quality of the terrain models greatly influence the clutter simulations. Higher resolution can produce finer cluttergrams, which assists in identifying possible subsurface features. One possible subsurface layering sequence is identified in one radargram.
Conclusions. A combination of radar observations, terrain models, and surface images reveals the dielectric constant of the surface deposit in Oxia Planum to be 4.9–8.8, indicating that the surface-covering material is made up of clay-bearing units in this region
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