This guide is for the wslg feature of windows 11.
Check for display:

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$ echo $DISPLAY
:0

if not, change it with:

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$ export DISPLAY=:0

check for X11 display socket

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$ ls -la /tmp/.X11-unix
lrwxrwxrwx 1 spronovo spronovo 19 Apr 21 15:28 /tmp/.X11-unix -> /mnt/wslg/.X11-unix

This is setup during WSL’s INIT.
If doesn’t exist, re-create it to try things out:

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$ sudo rm -r /tmp/.X11-unix
$ ln -s /mnt/wslg/.X11-unix /tmp/.X11-unix

Check whether X11 server is running:

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$ ls /tmp/.X11-unix
X0

Catalog

• Course Introduction
  * Common Tenses and Voices
• Writing Email
• Resume
• CV
• Peer-reviewed Article Publishing
• Citation
• Technical Project Deliverables

Course Introduction

What is TC?
Communication that presents specific information to a specific audience for a specific purpose

• who is audience?
• what information are we commmunicating?
• why are we communicating

Criteria of TC:

• Accuracy
• Brevity
• • no need for complex sentense, idea itself is complicated enough
• Clarify

Topics:

• Workplace-related communications
• Technical project design through a problem-need-solution framework
• Diagrams and data visualization, reporting results
• Paraphrasing, direct quotation, citation(AIAA)
• presentation skills

Requirements

• No late homework submission
• Attendance and active participation
• HC & plagiarism

Common Tenses and Voices

Tenses

• Use present tense a lot.
• If action happens in the past and is done, use past tense (if is true till now, use present tense(project, theorms))

Voices

• Use active voice, engaged and easier to read
• Use passive voice to put emphasis on action or the subject is unknow
• Do not use we, be objective

Writing Email

Components:

• address lines
• subject line
• salutation
• introduction, body and conclusion
• closing
• signiture
• signiture section

Notes:

• no conversation
• don’t send confidential information
• one single page is enough
• forward to others only when is authorized
• pause before sending
• clean out mailboxes

Three different levels of formality:

1. Personal, brief notes
2. Memo style
3. Letter style: formal business emails

Be careful when using !, it is super strong tone, meaning frustrated, very very angry.

Resume

Common traits

How to state your impact?

• What was differnent or better when you finish?
• What were obstacles and how did you get around them?
• What did you learn in that experience?

Name & Time:

• Yulin Chen
• Chen, Yulin
• May 2022

#CV
Sections:

• Contact info
• Education
• Experience
• Teaching

Peer-reviewed Article Publishing

Process

• Manuscript prepared by authors
• Submission(System)
• • may reject by AI if format is wrong
• Initial Eval.(Managing editor)
• • may reject if logic wrong
• Editor’s Eval.(Chief editors)
• • if not good enough, may reject
• Reviewing(Reviewers)
• read review advice(Editor)
• • if need author’s Rev. give back to author, then submit again
• • no thing required, publish
• • or reject if still not good enough

Citation

• name [index]
• endOfSentense [index1-index2].
• • the sentense is a summary of works cited ad index1-index2(multiple references)
• endOfSentense. [index]
• • cover several sentenses ahead

General Rule : if not cited, you are claiming that it is your own work.
Five-consecutive-word Rule
So we need paraphrasing

• Use different vacabulary
• Change order of words
• Different grammar/sentense structure

Style:

• MLA
• • Modern Language Association
• APA
• CMS
• AAAS
• AIAA
• ACS
• IEEE has many different styles

Technical Project Deliverables

Deliverables:

• Project
• Solution
• Finding
• Publication
• Patent
  all end up with a report

TC element

• Audience
• • Potential/existing customers, fellow engineers, colleagues from other departments
• • Professors, classmates, staffs
• • General readers interested
• Information
• • Project’s ‘result’ (not everything of the project)
• Purpose
• • Promote new product, share experience, establish status within, provide solution…

General Design Logic

• Describe problem at hand
• • General/broad topic
• • Narrow down gradually
• Analyze need

Study note for ROS subscriber.

Model of Topic

• Publisher(turtlesim)
• • –[Message(geometry_msgs::Twist)]–>
• Topic (/turtle1/pose)
• • –[Message(geometry_msgs::Twist)]–>
• Subscriber(Pose Listener)

Programming realization

How to realize a subscriber

• initialize ROS node
• subscribe required topic
• loop wait the msgs from topic, after receiving msgs, enter callback function
• implement msgs processing in the callback function

Code

Also we put this node into function package learning_topic
Create velocity_publisher.cpp file in learning_topic/src:

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#include <ros/ros.h>
#include <turtlesim/Pose.h>

void poseCallback(const turtlesim::Pose::ConstPtr& msg)
{
    ROS_INFO("Turtle pose: x:%0.6f, y:%0.6f, ",msg->x,msg->y);
}

int main(int argc, char *argv[])
{
    ros::init(argc, argv, "pose_subscriber");
    ros::NodeHandle n;
    ros::Subscriber pose_sub = n.subscribe("/turtle1/pose",10,poseCallback）
    //queue also first in first thrown
    //loop waiting for callback function, keep the endless loop
    ros::spin();
    return 0;
}

Note

• Callback function must be sufficient, or newer data will be blocked

Configure the compile run of subscriber

Steps same as publisher
Add two lines to learning\_topic/CMakeLists.txt (in build part):

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add_executable(velocity_publisher src/pose_subscriber.cpp)
target_link_libraries(pose_subsriber ${catkin_LIBRARIES})

Compile

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$ cd ~/ROS_study/catkin_ws
$ catkin_make
$ source ./devel/setup.zsh
$ roscore
$ rosrun turtlesim turtlesim_node
$ rosrun learning_topic velocity_publisher
$ rosrun learning_topic pose_subscriber

The output of pose_subscriber:

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...
[ INFO] [1650184199.757606156]: Turtle pose: x:3.100077, y:7.501662,
[ INFO] [1650184199.773327854]: Turtle pose: x:3.101826, y:7.493855,
[ INFO] [1650184199.790252785]: Turtle pose: x:3.103601, y:7.486054,
...

Studying note for regular expression

Definition

Regular expression describes a pattern of matching string
Can be used to detect/replace/take out specific substring

Syntax

Application in Cpp

In cpp, we use std::regex to express regular expression, supporting ECMAScripts as default.

Match

Use regex_match() to match xml (or html) format:

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std::regex reg("<.*>.*</.*>");

bool ret = std::regex_match("<xml>value</xml>",reg);
assert(ret);


bool ret = std::regex_match("<html>value</html>",reg);
assert(ret);

bool ret = std::regex_match("<xml>value<xml>",reg);
assert(ret);

Search

Use std::regex_search.
As long as there exists targets in the string, it will return.

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std::regex reg("<(.*)>(.*)</(\\1)>");
std::cmatch m;
auto ret = std::regex_search("123<xml>value</xml>456", m, reg);
if (ret){
    for (auto& elem : m)
        std::cout<<elem<<std::endl;
}