"When the system misidentifies a handwritten signature while recognizing files uploaded by users, I need to highlight the incorrect signature and key in the corresponding correct characters," she said. "Through repeated iterations, possibly thousands or tens of thousands of times, the system's ability to recognize various styles of handwritten Chinese characters will become stronger."

Zhang said the principles were similar when dealing with text, images or videos.

Her father died when she was in school, and Zhang and her three younger siblings depended on their mother's monthly income of 2,000 to 3,000 yuan as a migrant worker when they were growing up.

In 2019, after graduating from university, Zhang became a surveyor in Lanzhou and the main pillar of support for her family.

"My first project was in Longnan, where I had to draw houses, cars and mountains from aerial images onto a flat map," she said. "Sometimes I had to take a bus for a long time, go to rural areas or mountains for field surveys, and stay overnight. My colleagues were all male, so it was quite challenging."

Like many engineering jobs, Zhang said being a surveyor was not a particularly welcoming occupation for a woman. One time, she was experiencing severe abdominal pain but could not let it hinder her fieldwork. She climbed a high mountain with several male colleagues and, despite being exhausted, persevered so that she would not slow them down.

"With a monthly salary of around 3,000 yuan ($420), it was not enough to sustain myself considering the cost of renting a place and living expenses, let alone supporting my family," she said.

Another consideration that led to her decision to return to Jishishan was that her mother was growing older and it would be good to be closer to her.

"My mother is nearly 50 years old and illiterate," she said. "She hasn't had much education and could only do manual labor, such as picking cotton for a cotton factory in Xinjiang or working as a waitress in a restaurant."