Posts

WSPMax Read

Requirement-Driven Magnetic Beamforming for MIMO Wireless Power Transfer Optimization Motivation For the general MIMO setup, MultiSpot doesn’t consider peak current/voltage constraints. Yang et al. studied the magnetic beamforming problem in an MIMO MRC-WPT system to find all the boundary points of the multi-user power region with the peak current and voltage constraints for each TX. They simplified the problem by ignoring the mutual inductance among RXs. These researches lack the ability to control the power distribution among receivers, and could not be applied to the scenario when different RXs have different requirements of power which can be denoted as weight factors. Contribution We formulate the requirement-driven magnetic beamforming design in the MIMO MRC-WPT system as a weighted sum-power maximization problem. We consider the peak current/voltage constraints, and provides a high efficient, provable optimal solution.

Friday, December 13, 2024 | 3 minutes Read

Optimization Methods

Lagrangian relaxation The explanation I provide is based on Lagrangian relaxation-Wikipedia and Chapter 12 Lagrangian Relaxation-ens-lyon Lagrangian relaxation is a relaxation method which approximates a difficult problem of constrained optimization by a simpler problem. The method penalizes violations of inequality constraints using a Lagrange multiplier, which imposes a cost on violations. These added costs are used instead of the strict inequality constraints in the optimization. In practice, this relaxed problem can often be solved more easily than the original problem.

Thursday, December 12, 2024 | 11 minutes Read

Building issues

Issues 1. Built-in Shortcode leads to Hugo timeout. Because of the networks, I can’t send requests to Twitter, YouTube, etc. So I delete the contents about Twitter and YouTube. They are in content\posts\category\sub-category\rich-content\index.md, content\posts\category\sub-category\rich-content\index.bn.md, hugo.yaml shareButtons:, data\en\sections\about.yaml socialLinks:. 2. Only readme when deploying to github pages. Need to set your deployment branch to gh-pages.

Sunday, November 24, 2024 | 1 minute Read

Matrix Base

0.1 Determinant Theorem: $ det(AB) = det(A)det(B) $ Let $ A, B $ be a square matrices of order n. Let $ det(A) $ be the determinant of $ A $. Let $ AB $ be the matrix product of $ A $ and $ B $. Then: $ det(AB) = det(A)det(B) $ Proof The proof I provide is based on Determinant of Matrix Product Consider two cases: $ A $ is singular.

Wednesday, November 20, 2024 | 56 minutes Read

MagMIMOHotspot Read

Magnetic MIMO: how to charge your phone in your pocket Motivation Current wireless chargers need to remember to regularly charge our mobile phones which is not the wireless charging we hoped for. We would like to have our cell phones charged in our pockets, and never again worry about forgetting to charge the phone. MIMO RF techniques power phones remotely, however, delivering a large amount of power via radiation can cause local heating inside the human body. Contribution They propose a novel design that focuses the magnetic flux from multiple coils in a steerable beam and points it at the phone, in a manner analogous to multi-antenna beamforming in wireless communications. The design can charge unmodified smart phones at distances up to 40 cm, and works regardless of the phone orientation with respect to the charging pad. Magnetic-Beamforming Figure 1: Illustration of the analogies between standard MIMO and MagMIMO. For a 2-antenna MIMO transmitter.

Thursday, November 7, 2024 | 7 minutes Read

Circuit Base

Basic circuit Charge It is defined in terms of the ampere by counting the total charge that passes through an arbitrary cross section of a wire during an interval of one second. In the SI system, the fundamental unit of charge is the coulomb (C). Current We define the current at a specific point and flowing in a specified direction as the instantaneous rate at which net positive charge is moving past that point in the specified direction. Current is symbolized by I or i, and so

Thursday, November 7, 2024 | 3 minutes Read

First glance

Scheduling Layer PTE Optimization Requirement-Driven Magnetic Beamforming for MIMO Wireless Power Transfer Optimization Motivation: In MIMO MRC-WPT system, we need to consider the scenario when different RXs have different requirements of power. Problem formulation: weighted sum-power maximization $WSPMax = max_{{i_n^{tx}}} \sum_q w_q |i^{rx}_q|^2 r^{rx}_q $ Subject to: $$ \sum_n \left|i_n^{tx}\right|^2 r_n^{tx} + \sum_q \left|i_q^{rx}\right|^2 r_q^{rx} \leq P_{\text{max}}, \ $$ $$ \left|i_n^{tx}\right|^2 \leq A_n^{tx}, \quad \forall 1 \leq n \leq N, \ $$

Thursday, October 31, 2024 | 5 minutes Read

Multimodal-fusion research

Fusion stage Figure 1: Mind map of Deep Multimodal Learning Inference mechanism for multi-sensors fusion Figure 2: Mind map of A comparative review on multi-modal sensors fusion based on deep learning

Wednesday, October 16, 2024 | 1 minute Read

Recommendation Progress

个人情况本科：重庆大学专业：计算机科学与技术排名： 1.3% (rank 3) 英语：六级 547 荣誉：国家奖学金、重庆市三好学生竞赛：无竞赛科研：有 CV 领域相关经历，面试时有 NIPS 二作在投最终去向：中国科学技术大学-计算机科学与技术学院夏令营情况院校类型入营 offer 南京大学-计算机科学与技术学院硕士 √ 候补清华大学-深圳国际研究生院(数据与信息研究院人工智能项目) 硕士 × 清华大学-网络研究院硕士 × 南京大学-人工智能学院硕士 × 中国人民大学-高瓴人工智能学院直博 √ 时间冲突，放弃参营上海交通大学-人工智能学院直博 √ 不合格（斩杀）中国科学技术大学-计算机科学与技术学院硕士 √ 学硕南京大学-计算机科学与技术学院线上测试过了，线下机试 0 分。。。南京大学-人工智能学院入了计院，不让入人工智能学院？上海交通大学-人工智能学院没有提前联系好老师，科研积累太少。预推免情况院校类型入营 offer 清华大学-软件学院专硕 √ × 浙江大学-计算机科学与技术学院硕士 √ 专硕总结：入营基本都能入，但自身实力差。南大机试报零，面试差导致上交直博不合格。

Thursday, October 10, 2024 | 1 minute Read

C language lecture 1

怎么和计算机打交道 Figure 1: 早期将穿孔纸带输入计算机 Figure 2: 使用汇编语言编程 Figure 3: 使用高级语言C语言编程为什么要学 C 语言基础性强：C 语言是一门底层语言，靠近计算机硬件。学习 C 语言能够帮助你理解计算机是如何工作的，如内存管理、指针操作和硬件交互等。很多高级语言（如 C++、Python）都基于 C 语言。高效性能：C 语言生成的代码通常比很多高级语言效率更高，特别适合对性能要求高的场景，比如实时系统、游戏引擎等。。。。怎么开始学习 C/C++ 语言首先需要一个写代码的好地方，推荐 VS Code 安装 VS Code 安装 C/C++ 扩展安装 MinGW-w64 编译工具，并检查向编程世界打声招呼 #include <iostream> using namespace std; int main() { cout << "Hello, World!" << endl; return 0; }

Friday, September 13, 2024 | 1 minute Read

transformer Read

Questions What’s the number of operations required to relate signals from two arbitrary input or output positions grows in the distance between positions ? Extended Learning Attention mechanisms with a recurrent network. Bahdanau, Dzmitry. “Neural machine translation by jointly learning to align and translate.” arXiv preprint arXiv:1409.0473 (2014). Use convolutional neural networks to compute hidden representations in parallel. Gehring, Jonas, et al. “Convolutional sequence to sequence learning.” International conference on machine learning. PMLR, 2017.

Thursday, September 12, 2024 | 1 minute Read

DINO Read

Questions What’s the function of centering $ C $ and sharpening parameter $ \tau_t $ ? Extended Learning Multi-crop training. Caron, Mathilde, et al. “Unsupervised learning of visual features by contrasting cluster assignments.” Advances in neural information processing systems 33 (2020): 9912-9924. Use a noise contrastive estimator (NCE) to compare instances instead of classifying them. Wu, Zhirong, et al. “Unsupervised feature learning via non-parametric instance discrimination.” Proceedings of the IEEE conference on computer vision and pattern recognition. 2018.

Friday, September 6, 2024 | 1 minute Read