179 research outputs found
Revenue Management Through Dynamic Cross Selling in E-Commerce Retailing
We consider the problem of dynamically cross-selling products (e.g., books) or services (e.g., travel reservations) in the e-commerce setting. In particular, we look at a company that faces a stream of stochastic customer arrivals and may offer each customer a choice between the requested product and a package containing the requested product as well as another product, what we call a “packaging complement.” Given consumer preferences and product inventories, we analyze two issues: (1) how to select packaging complements, and (2) how to price product packages to maximize profits.
We formulate the cross-selling problem as a stochastic dynamic program blended with combinatorial optimization. We demonstrate the state-dependent and dynamic nature of the optimal package selection problem and derive the structural properties of the dynamic pricing problem. In particular, we focus on two practical business settings: with (the Emergency Replenishment Model) and without (the Lost-Sales Model) the possibility of inventory replenishment in the case of a product stockout. For the Emergency Replenishment Model, we establish that the problem is separable in the initial inventory of all products, and hence the dimensionality of the dynamic program can be significantly reduced. For both models, we suggest several packaging/pricing heuristics and test their effectiveness numerically
Application of NOMA in 6G Networks: Future Vision and Research Opportunities for Next Generation Multiple Access
As a prominent member of the next generation multiple access (NGMA) family,
non-orthogonal multiple access (NOMA) has been recognized as a promising
multiple access candidate for the sixth-generation (6G) networks. This article
focuses on applying NOMA in 6G networks, with an emphasis on proposing the
so-called "One Basic Principle plus Four New" concept. Starting with the basic
NOMA principle, the importance of successive interference cancellation (SIC)
becomes evident. In particular, the advantages and drawbacks of both the
channel state information based SIC and quality-of-service based SIC are
discussed. Then, the application of NOMA to meet the new 6G performance
requirements, especially for massive connectivity, is explored. Furthermore,
the integration of NOMA with new physical layer techniques is considered,
followed by introducing new application scenarios for NOMA towards 6G. Finally,
the application of machine learning in NOMA networks is investigated, ushering
in the machine learning empowered NGMA era.Comment: 14 pages, 5 figures, 1 tabl
Knowledge-Driven Semantic Segmentation for Waterway Scene Perception
Semantic segmentation as one of the most popular scene perception techniques has been studied for autonomous vehicles. However, deep learning-based solutions rely on the volume and quality of data and knowledge from specific scene might not be incorporated. A novel knowledge-driven semantic segmentation method is proposed for waterway scene perception. Based on the knowledge that water is irregular and dynamically changing, a Life Time of Feature (LToF) detector is designed to distinguish water region from surrounding scene. Using a Bayesian framework, the detector as the likelihood function is combined with U-Net based semantic segmentation to achieve an optimized solution. Finally, two public datasets and typical semantic segmentation networks, FlowNet, DeepLab and DVSNet are selected to evaluate the proposed method. Also, the sensitivity of these methods and ours to dataset is discussed
Overcoming DoF Limitation in Robust Beamforming: A Penalized Inequality-Constrained Approach
A well-known challenge in beamforming is how to optimally utilize the degrees
of freedom (DoF) of the array to design a robust beamformer, especially when
the array DoF is smaller than the number of sources in the environment. In this
paper, we leverage the tool of constrained convex optimization and propose a
penalized inequality-constrained minimum variance (P-ICMV) beamformer to
address this challenge. Specifically, we propose a beamformer with a
well-targeted objective function and inequality constraints to achieve the
design goals. The constraints on interferences penalize the maximum gain of the
beamformer at any interfering directions. This can efficiently mitigate the
total interference power regardless of whether the number of interfering
sources is less than the array DoF or not. Multiple robust constraints on the
target protection and interference suppression can be introduced to increase
the robustness of the beamformer against steering vector mismatch. By
integrating the noise reduction, interference suppression, and target
protection, the proposed formulation can efficiently obtain a robust beamformer
design while optimally trade off various design goals. When the array DoF is
fewer than the number of interferences, the proposed formulation can
effectively align the limited DoF to all of the sources to obtain the best
overall interference suppression. To numerically solve this problem, we
formulate the P-ICMV beamformer design as a convex second-order cone program
(SOCP) and propose a low complexity iterative algorithm based on the
alternating direction method of multipliers (ADMM). Three applications are
simulated to demonstrate the effectiveness of the proposed beamformer.Comment: submitted to IEEE Transactions on Signal Processin
Knowledge-driven Meta-learning for CSI Feedback
Accurate and effective channel state information (CSI) feedback is a key
technology for massive multiple-input and multiple-output systems. Recently,
deep learning (DL) has been introduced for CSI feedback enhancement through
massive collected training data and lengthy training time, which is quite
costly and impractical for realistic deployment. In this article, a
knowledge-driven meta-learning approach is proposed, where the DL model
initialized by the meta model obtained from meta training phase is able to
achieve rapid convergence when facing a new scenario during target retraining
phase. Specifically, instead of training with massive data collected from
various scenarios, the meta task environment is constructed based on the
intrinsic knowledge of spatial-frequency characteristics of CSI for meta
training. Moreover, the target task dataset is also augmented by exploiting the
knowledge of statistical characteristics of wireless channel, so that the DL
model can achieve higher performance with small actually collected dataset and
short training time. In addition, we provide analyses of rationale for the
improvement yielded by the knowledge in both phases. Simulation results
demonstrate the superiority of the proposed approach from the perspective of
feedback performance and convergence speed.Comment: arXiv admin note: text overlap with arXiv:2301.1347
Association between Ghrelin gene (GHRL) polymorphisms and clinical response to atypical antipsychotic drugs in Han Chinese schizophrenia patients
<p>Abstract</p> <p>Background</p> <p>Ghrelin (<it>GHRL</it>) is a pivotal peptide regulator of food intake, energy balance, and body mass. Weight gain (WG) is a common side effect of the atypical antipsychotics (AAPs) used to treat schizophrenia (SZ). Ghrelin polymorphisms have been associated with pathogenic variations in plasma lipid concentrations, blood pressure, plasma glucose, and body mass index (BMI). However, it is unclear whether <it>GHRL </it>polymorphisms are associated with WG due to AAPs. Furthermore, there is no evidence of an association between <it>GHRL </it>polymorphisms and SZ or the therapeutic response to AAPs. We explored these potential associations by genotyping <it>GHRL </it>alleles in SZ patients and controls. We also examined the relation between these SNPs and changes in metabolic indices during AAP treatment in SZ subgroups distinguished by high or low therapeutic response.</p> <p>Methods</p> <p>Four SNPs (Leu72Met, -501A/C, -604 G/A, and -1062 G > C) were genotyped in 634 schizophrenia patients and 606 control subjects.</p> <p>Results</p> <p>There were no significant differences in allele frequencies, genotype distributions, or the distributions of two SNP haplotypes between SZ patients and healthy controls (<it>P </it>> 0.05). There was also no significant difference in symptom reduction between genotypes after 8 weeks of AAP treatment as measured by positive and negative symptom scale scores (PANSS). However, the -604 G/A polymorphism was associated with a greater BMI increase in response to AAP administration in both APP responders and non-responders as distinguished by PANSS score reduction (<it>P </it>< 0.001). There were also significant differences in WG when the responder group was further subdivided according to the specific AAP prescribed (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>These four <it>GHRL </it>gene SNPs were not associated with SZ in this Chinese Han population. The -604 G/A polymorphism was associated with significant BW and BMI increases during AAP treatment. Patients exhibiting higher WG showed greater improvements in positive and negative symptoms than patients exhibiting lower weight gain or weight loss.</p
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