159 research outputs found
The Impact of RFID on Firm and Supply Chain Performance: a Simulation Study
Radio Frequency Identification (RFID) is a tracking technology that enables firms to digitize their supply chain processes and manage their supply chain activities efficiently and effectively. This study develops an analytical model of the impact of RFID use on inventory accuracy and on the firm-level and supply chain-level performance of a single product line. Due to the complexity of the analytical model, we propose to analyze the model using simulation and to gain insights into the behaviors of the various players in the supply chain. This research in progress will help better understand RFID value in supply chain, from an inventory management perspective and also bring into focus the impact of product type and technology development status on technology use
Peak-to-average power ratio analysis for OFDM-based mixed-numerology transmissions
In this paper, the probability distribution of the peak to average power ratio (PAPR) is analyzed for the mixed numerologies transmission based on orthogonal frequency division multiplexing (OFDM). State of the art theoretical analysis implicitly assumes continuous and symmetric frequency spectrum of OFDM signals. Thus, it is difficult to be applied to the mixed-numerology system due to its complication. By comprehensively considering system parameters, including numerology, bandwidth and power level of each subband, we propose a generic analytical distribution function of PAPR for continuous-time signals based on level-crossing theory. The proposed approach can be applied to both conventional single numerology and mixed-numerology systems. In addition, it also ensures the validity for the noncontinuous-OFDM (NC-OFDM). Given the derived distribution expression, we further investigate the effect of power allocation between different numerologies on PAPR. Simulations are presented and show the good match of the proposed theoretical results
Research Progress of Electrically Controlled Reconfigurable Polarization Manipulation Using Metasurface
Metasurfaces are two-dimensional artificial structures with numerous subwavelength elements arranged periodically or aperiodically. They have demonstrated their exceptional capabilities in electromagnetic wave polarization manipulation, opening new avenues for manipulating electromagnetic waves. Metasurfaces exhibiting electrically controlled reconfigurable polarization manipulation have garnered widespread research interest. These unique metasurfaces can dynamically adjust the polarization state of electromagnetic waves through real-time modification of their structure or material properties via electrical signals. This article provides a comprehensive overview of the development of metasurfaces exhibiting electrically controlled reconfigurable polarization manipulation and explores the technological advancements of metasurfaces with different transmission characteristics in the microwave region in detail. Furthermore, it delves into and anticipates the future development of this technology
Multi-UAV simultaneous target assignment and path planning based on deep reinforcement learning in dynamic multiple obstacles environments
Target assignment and path planning are crucial for the cooperativity of multiple unmanned aerial vehicles (UAV) systems. However, it is a challenge considering the dynamics of environments and the partial observability of UAVs. In this article, the problem of multi-UAV target assignment and path planning is formulated as a partially observable Markov decision process (POMDP), and a novel deep reinforcement learning (DRL)-based algorithm is proposed to address it. Specifically, a target assignment network is introduced into the twin-delayed deep deterministic policy gradient (TD3) algorithm to solve the target assignment problem and path planning problem simultaneously. The target assignment network executes target assignment for each step of UAVs, while the TD3 guides UAVs to plan paths for this step based on the assignment result and provides training labels for the optimization of the target assignment network. Experimental results demonstrate that the proposed approach can ensure an optimal complete target allocation and achieve a collision-free path for each UAV in three-dimensional (3D) dynamic multiple-obstacle environments, and present a superior performance in target completion and a better adaptability to complex environments compared with existing methods
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Platform opening and cooperation: a literature review and research agenda
Purpose – The review aims to facilitate a broader understanding of platform opening and cooperation and points out potential research directions for scholars.
Design/methodology/approach – This study searches Web of Science (WOS) database for relevant literature published between 2010 and 2021 and selects 86 papers for this review. The selected literature is categorized according to three dimensions: the strategic choice of platform opening and cooperation (before opening), the construction of an open platform (during opening) and the impact of platform opening and cooperation (after opening). Through comparative analysis, the authors identify research gaps and propose four future research agendas.
Findings – The study finds that the current studies are fragmented, and a research system with a theoretical foundation has not yet formed. In addition, with the development of platform operations, new topics such as platform ecosystems and open platform governance have emerged. In short, there is an urgent need for scholars to conduct exploratory research. To this end, the study proposes four future research agendas: strengthen basic research on platform opening and cooperation, deeply explore the dynamic evolution and cutting-edge models of platform opening and cooperation, analyze potential crises and impacts of platform openness and strengthen research on open platform governance.
Originality/value – This is the first systematic review on platform opening and cooperation. Through categorizing literature into three dimensions, this article clearly shows the research status and provides future research avenues
Rethinking Semi-Supervised Medical Image Segmentation: A Variance-Reduction Perspective
For medical image segmentation, contrastive learning is the dominant practice
to improve the quality of visual representations by contrasting semantically
similar and dissimilar pairs of samples. This is enabled by the observation
that without accessing ground truth label, negative examples with truly
dissimilar anatomical features, if sampled, can significantly improve the
performance. In reality, however, these samples may come from similar
anatomical features and the models may struggle to distinguish the minority
tail-class samples, making the tail classes more prone to misclassification,
both of which typically lead to model collapse. In this paper, we propose ARCO,
a semi-supervised contrastive learning (CL) framework with stratified group
sampling theory in medical image segmentation. In particular, we first propose
building ARCO through the concept of variance-reduced estimation, and show that
certain variance-reduction techniques are particularly beneficial in medical
image segmentation tasks with extremely limited labels. Furthermore, we
theoretically prove these sampling techniques are universal in variance
reduction. Finally, we experimentally validate our approaches on three
benchmark datasets with different label settings, and our methods consistently
outperform state-of-the-art semi-supervised methods. Additionally, we augment
the CL frameworks with these sampling techniques and demonstrate significant
gains over previous methods. We believe our work is an important step towards
semi-supervised medical image segmentation by quantifying the limitation of
current self-supervision objectives for accomplishing medical image analysis
tasks
Synthesis of epitaxial magnetic pyrochlore heterojunctions
The synthesis of stoichiometric and epitaxial pyrochlore iridate thin films
presents significant challenges yet is critical for unlocking experimental
access to novel topological and magnetic states. Towards this goal, we unveil
an in-situ two-stage growth mechanism that facilitates the synthesis of
high-quality oriented pyrochlore iridate thin films. The growth starts with the
deposition of a pyrochlore titanate as an active iso-structural template,
followed by the application of an in-situ solid phase epitaxy technique in the
second stage to accomplish the formation of single crystalline, large-area
films. This novel protocol ensures the preservation of stoichiometry and
structural homogeneity, leading to a marked improvement in surface and
interface qualities over previously reported methods. The success of this
synthesis approach is attributed to the application of directional laser-heat
annealing, which effectively reorganizes the continuous random network of ions
into a crystalline structure, as evidenced by our comprehensive analysis of the
growth kinetics. This new synthesis approach advances our understanding of
pyrochlore iridate film fabrication and opens a new perspective for
investigating their unique physical properties.Comment: 11 pages, 4 figures; supplementary materials (1 table, 6 figures
StepCoder: Improve Code Generation with Reinforcement Learning from Compiler Feedback
The advancement of large language models (LLMs) has significantly propelled
the field of code generation. Previous work integrated reinforcement learning
(RL) with compiler feedback for exploring the output space of LLMs to enhance
code generation quality. However, the lengthy code generated by LLMs in
response to complex human requirements makes RL exploration a challenge. Also,
since the unit tests may not cover the complicated code, optimizing LLMs by
using these unexecuted code snippets is ineffective. To tackle these
challenges, we introduce StepCoder, a novel RL framework for code generation,
consisting of two main components: CCCS addresses the exploration challenge by
breaking the long sequences code generation task into a Curriculum of Code
Completion Subtasks, while FGO only optimizes the model by masking the
unexecuted code segments to provide Fine-Grained Optimization. In addition, we
furthermore construct the APPS+ dataset for RL training, which is manually
verified to ensure the correctness of unit tests. Experimental results show
that our method improves the ability to explore the output space and
outperforms state-of-the-art approaches in corresponding benchmarks. Our
dataset APPS+ and StepCoder are available online.Comment: 13 pages, 5 figure
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