概率整形和几何整形

1. 概率整形

a. the low-amplitude constellation points are sent with a high probability than the high-amplitude ones. Besides, the constellation points under the same amplitude layer are sent equally likely. Therefore, the average symbol power will be decreased, but at a cost of lower source entropy.

b. The first PS scheme was proposed by Gallager, which is based on many-to-one mapping.

c. There are some methods proposed to further reduce the complexity of CCDM, like multiset-partition distribution matching and sreaming distribution matching.

2. CCDM

a. K-L散度(相对熵)

jianshu.com/p/43318a3dc715

b. All approaches are variable length, which can lead to varying transmission rate, large buffer sizes, error propagation and synchronization problem.

fixed-to-fixed length codes do not have these issues.

Autopilot Simulation, Tools Engineer

https://www.tesla.cn/careers/job/autopilot-simulationtoolsgineer-50003

The Role

Autopilot is of critical importance to Tesla’s mission. It is safer, makes driving more enjoyable, and will ultimately deliver on the promise of self-driving cars. As a member of Tesla’s Autopilot Simulation team, you will be in a unique position to accelerate the pace at which Autopilot improves over time. The main ways in which the simulation team realizes this include:

  • building tools that enable Autopilot software developers to perform virtual test drives instead of real ones
  • testing all Autopilot software releases for regressive behavior
  • generating synthetic data sets for neural network training

The foundation on which we build these elements is our simulation environment. We develop photorealistic worlds for our virtual car to drive in, enabling our developers to iterate faster and rely less on real-world testing. We strive for perfect correlation to real-world vehicle behavior and work with Autopilot software engineers to improve both Autopilot and the simulator over time. Our group is a cross-disciplinary team with people from various backgrounds and fields of expertise, like CS generalists, mechanical engineers, game developers, and computer graphics artists. As a member on this team, you will be challenged to learn about all these different disciplines and use your own expertise to further improve the scope and usability of our tools.

As an Autopilot Simulation Tools Engineer, you will contribute to the development of the simulation by building tools that enable rapid prototyping/testing of Autopilot. You will be expected to contribute to such projects as photorealistic world generation, simulation scenario authoring, performance evaluation, and content validation tools. These simulation tools will both assist the simulation team and the broader Autopilot organization in both feature creation and performance improvement.

Responsibilities

    • Design and develop various content creation, simulation, reporting, and build tools
    • Contributing to the development of a modular, scalable simulation platform
    • Work with all members of the Autopilot team to understand simulation tooling requirements and champion good development/testing processes
    • Leverage and improve existing tools

Requirements

    • Experience developing and delivering engineering tools
    • Excellent software development skills in C++ & Python
    • BS/MS in Engineering, Computer Science, or the equivalent in experience and evidence of exceptional ability
    • Comfortable developing with Linux & Git
    • Knowledge of software life cycle, modern testing methods, and solid understanding of continuous integration
    • Able to work independently and proactively
    • Desirable to have experience working with and developing tools for Unreal Engine 4, Maya, and/or Houdini