A CLUSTER OF FLOWERS

 Yesterday, I finished painting a watercolour picture titled "A Cluster of Flowers". It features a cluster of yellow flowers that I saw in the City Botanic Gardens of Brisbane.

I used watercolour pencils to draw the outlines and applied the colours inside using pan-based watercolour pigments. However, I soon regretted using an orange pencil to draw the petals. I thought I could make them much lighter by wiping them with a brush dipped in clean water. Unfortunately, the result is that the edges are still too dark. I should have used a yellow pencil instead.

Overall, I am quite satisfied with the flowers. The different layers of colours and green leaves are vivid. However, I am not happy with the background, meaning the soil on the ground and the bush in the far field. The light conditions of the background are also not well painted. I think in my next picture, I will try to apply just a single layer of very light, smooth colour for the background. A looser style will be better to make the foreground objects stand out.

Rest Yourself

 I was supervising my son practising the piano in the evening. He was playing a new song that he had just learned from his last lesson. At the beginning, he felt frustrated, but he continued to progress until he could play the whole song with few errors.

"Hooray!" I cheered with him.

He looked at me and asked, "Is it really good?"

I nodded my head. He then merrily rushed to the bedroom to tell his mum. His mum encouraged him to play it again.

However, he made some silly mistakes. Then he tried again, and then again and again. It was a pity that he couldn't play it as well as before.

"Why not take a rest?" I suggested. He then went to play with his toy cars for a little while.

"You've practised enough," I said to him. "Maybe you can try again tomorrow."

But he didn't listen to me and quickly sat on the piano bench. He tried to play the music, and it was even better than all his previous attempts. He then tried again, and it was almost perfect to my ears.

"Yeah, when you encounter a puzzle that you can't solve immediately, please take a rest and then try again. Resting is as important as practising. A good way to rest is to switch your focus to other activities," I told him.

About BUTTERFLY LOVERS

 Recently, the famous Chinese composer Chen Gang passed away. Chen Gang was mostly known as one of the two composers of the violin concerto "Butterfly Lovers", and thus yesterday I played this music on xiao to pay homage to him.

The story of the Butterfly Lovers is interesting, and it is even more interesting in modern society, where everything has to be labeled clearly. In the old days, only boys could be admitted to school. Therefore, a girl named Zhu Yingtai disguised herself as a boy to study in a college, where she built a good friendship with one of her classmates named Liang Shanbo. When Shanbo discovered Yingtai's true gender, he wanted to marry her, but Yingtai was already engaged to someone else through an arrangement by her parents. Eventually, both of them died for love and transformed into a pair of butterflies to live together.

This story, in modern society, can trigger a number of questions. Is Shanbo gay? When he studied together with Yingtai, Yingtai was dressed like a boy, but she was in fact a girl. This situation is somewhat similar to today's transgender people. Is this type of love classified as homosexual love? Is there any boundary between same-sex classmate friendship and the love of lovers? We can think about a lot of these aspects.

Then eventually, I believe most people will agree with the point that people in modern times consider too much. There is, in fact, little difference among different sentiments.

Sincerity and Hypocrisy (continued)

When July of 2008 came, I was thinking about whether to go to Shenzhen. Finally, I went there because I wanted to understand what would happen. I knew it was most likely that they would not keep their promise, but I was still keen to get a clear answer. 

Nevertheless, even if I stayed there for only a day, ZTE would have to pay me. As a fresh graduate, I could also stay in the company’s temporary accommodation for three weeks.

On the first day that I arrived at the office, I met Mr. Wang, who was the head of the department. For fresh graduates like me, there was training soon. Each graduate would be assigned a mentor. 

I clearly remember that when Mr. Wang led me to my mentor, he said, "This graduate had a very excellent academic performance at school. Please pay more attention to his training."

The department arranged lectures for us. Senior Engineers from ZTE Corporation were the lecturers. Each graduate received training materials, such as books, paper documents, and software installed on computers. 

The lecturers illustrated to us topics about wireless network planning and optimization. After each lecture, there would be time for us to read materials and practice on the simulation software platforms. 

Every day my mentor would ask me some questions. "Do you understand what the lectures are about?" he asked.

"Yes," I said, and explained my understanding.

"Can you tell me about the direction of antennas?" He asked me one day.

"Yes. There are two types of antennas," I said. "One of them is called omnidirectional antennas, and the other is directional antennas." 

Then I continued, "Omnidirectional antennas transmit power equally in all directions, while a directional antenna transmits signals with different power in different directions. But for analysis, we can view a directional antenna as an array of omnidirectional antennas, with certain configurations such as phase shifts and geometric allocations."

He smiled and asked another question, "How do you choose different types of antennas for network planning? Can you explain with examples?"

"For a straight road with few residential buildings on both sides, we can choose a single-direction antenna to focus more on the road, whereas for a village, we can put an omnidirectional antenna on top of a hill so that it can easily cover the whole area," I replied. He nodded his head while listening.

I also had discussions with peers in the graduate program. We shared our understanding of the techniques with each other and built friendships. When I had questions, I would ask my mentor. "Are the convolutional codes for CDMA fully orthogonal?" I asked my mentor one day.

"Not fully," he said.

Every morning the company arranged a shuttle bus to carry us to the office, and in the evening we arrived at the temporary accommodation by shuttle bus. I was living with three master’s graduates: one in the HR department, one in a software R&D position, and one in a hardware R&D position. We had majored in different fields, so we shared our knowledge and discussed a lot every evening. 

They were startled when they saw me reading books as thick as pillows, which I had borrowed from the ZTE library. 

"How can you read English books as fast as Chinese ones?" they asked. 

"Because I spent more than half of my effort learning English during my undergraduate course," I replied.

No one thought I would quit the job. I was afraid that I would lose the opportunity for training if I told any of them. At the end of the training program, I called Mr. Wang to say that I wanted to resign.

"What? How could you stay for just a few weeks? Which university did you graduate from?" he said angrily.

"We graduated from the same university," I told him. "Could you please help me? I am innocent..."

"Have you encountered something unhappy here?" He softened his voice and said, "When did you start wanting to leave?"

"I'm grateful that everyone has been nice to me. We've built friendships and I have really learned a lot. But I've wanted to break the contract for more than half a year..."

After I told my roommates, they were all shocked. They were concerned about me. They recommended me to the R&D department where they were working. They contacted their former classmates to see if they could help me, which touched me.

I left Shenzhen at the same time when the Beijing Olympics started. Before I left, two of my best friends from university had arrived in Shenzhen and we had dinner together. Last year when we signed contracts with ZTE together, we agreed with each other that if in the future any of us was appreciated by the boss, Mr. Hou, he should raise the salaries of the others after being promoted. They looked sad at dinner.

I told them I had got three weeks' salary and would like to pay for dinner. They refused and worried about my future.

Some years later, when I was in Brisbane, one of them settled in Hangzhou, and the other in Xi'an. In 2016, I visited Hangzhou and met my former colleague, together with two university friends.

At that time in my mind, they were three of my best friends at university. But they all said they had never believed I was their close friend. I was hurt. 

Almost at the same time, I met a university roommate in Shanghai. He said he had hoped that one day everyone from our dormitory could gather together again in Xi'an.

I dared not visit Xi'an again, because Xi'an was related to memories of the happiest past days and best friends. I know that Xi'an nowadays is very different from the city I once lived, and so are my best friends. Never visiting there again means I can keep those good memories forever in my mind.

No Panic for AI

When everyone is talking about AI and worrying about AI, especially worrying about losing jobs due to AI, I strongly believe that the spring of AI has yet to come. Please, no panic for it.

Am I joking? Haven’t I seen the emergence of products like chatting robots or the revolution of deep learning?

The chatting robots that are based on generative AI are basically trained by text. There are some developments on audio and images, but not that much for video, as the size of video is still too big for most machine learning platforms.

In addition, these robots only generate answers that look good. I mean, the flow of language is smooth and without grammar mistakes, but the content is still of low quality. This is because it is still based on a strong assumption that all information in the training dataset is correct. To filter out incorrect information in the training dataset requires tedious human labor, which means the development of AI products itself requires large human resources who don’t have to know the underlying theories.

Therefore, please don’t panic about losing jobs, even when you don’t know much of the technique.

Have you got experience comparing texts and videos on your computer? The size of a two-hour movie will be much larger than a huge number of text-based novels. This is why I think the techniques are still vulnerable when it comes to analyzing videos.

The annotation of images or videos will be even more challenging.

In a lot of situations, if we want to detect unusual events, for example, dangerous driving in traffic surveillance, it is still an unsolved problem to collect a dataset with a sufficient number of those events. Simulation is a direction, but there is no real research in this direction so far.

Process mining looks fantastic. But do you know that the log data in information systems are not in the format that can be used directly by the algorithms? There is a tedious process to prepare data initially and there are many ambiguous matters.

Many papers that use deep learning techniques on small datasets claim that the proposed techniques are more advanced than using shallow learning like SVM. But in fact, they simply get good experimental results due to overfitting on the small datasets.

The ambitious proposal of channel sensing in communication channels in 6G is unrealistic at this stage. There is a lack of foundation from machine learning theories to experimental designs in this area. How can it be real around 2030?

 

The Composition of the GO TO SCHOOL Song

Yesterday, I made a video recording of a song that I composed last year. The name of the song is "GO TO SCHOOL". It was composed when my older son just started prep. A few months before this, I wrote a nursery rhyme for my younger son's birthday. As a father, I know I should love the two boys equally, without favoring one over the other. To prove that I loved the older brother too, I felt I had to compose a piece of music for him.

The melody is relatively fast. There are notes moving up and down with large gaps, as if the kids are bouncing and jumping while going to school. They sometimes are running and become excited when they reach school and greet their teachers and friends. The music is composed in upbeat rhythms, indicating the energy of young children.

Sincerity and Hypocrisy

In 2017, when I was in the trough of my life, I went to China before starting a new job in Shenzhen.

Having not met my university classmates for almost ten years, those who worked in Shenzhen held a gathering in a Cantonese restaurant to welcome my return to China. After lunch, those who had married went home, leaving only one who was still single to accompany me.

"Little New, I know you've suffered a lot due to ZTE. But please don't talk about this unhappy past anymore, as you should move on from it and look forward to the future. Nevertheless, the HR who hired you had resigned a couple of years after you left," he said. Then he continued, "Don't be too attached to friends who have blocked you. I know you felt hurt, but there are many more classmates who wanted to contact you."

I am still grateful for his concern for me. However, when looking back at the stories in ZTE Corporation, I deem it a matter of pride rather than suffering, as it is not easy for an undergraduate student to be 'deceived' by a multinational tech giant.

Especially, I strongly felt the kindness from others in ZTE when I submitted my application to resign.

"I only want to go to the R&D department," I said to the interviewers at the Tangcheng Hotel, where the ZTE campus recruitment team was.

"But our company has a policy of only recruiting graduates with a master's degree or above for R&D positions," they said.

"If it is impossible, I think we don't need to waste time on the interview," I said.

"But since you've come here today, why not go through the interview process first?"

Then they asked me questions about communications techniques.

"For the seven layers of the TCP/IP protocol, which layers were implemented by hardware? "One interviewer asked.

"This question is a bit meaningless. Any electronic system cannot function without hardware. With basic hardware, any algorithm can be designed using software or hardware, depending on whether you want it to be easier to configure or to perform faster," I said.

"Your answer is interesting, and I quite agree with you..."

"Do you know how to judge if a communication system is synchronized?" He asked.

"If you can see an eye diagram on the oscilloscope," I said.

"Why can you see an eye diagram when it is synchronized?" The other interviewer asked.

"When a system has been synchronized, the sine signals can be grouped into two sets. In each set, all the peaks and troughs are at the same time, whereas the peaks match the troughs of the other set, forming an eye shape," I responded.

They nodded their heads and asked, "Can you tell me your understanding of coding?"

"In a communication system, there are two types of coding: source coding, which aims to reduce the size of information in the data to transmit, and channel coding, which adds redundant information that is used to recover the data for corrupted data," I said.

"How do you consider the techniques in source and channel coding?" He continued to question.

"For source coding, I think we need to consider the size of the source data and the level of redundancy. If you're sending text data, I don't think it is a priority to compress it, whereas for high-resolution video of a blue sky, it is different... For channel coding, it depends on the environment of the communication channel. It is more important in wireless communications. They also depend on the resources you have and the error rates that need to be achieved..."

"But are they the only coding techniques in a communication system?" The other interviewer interrupted me. "Besides the two, we also have PCM coding when converting an analog signal to its digital form."

I then explained the theory and said, "The international standards allocate more codes for signals in the lower frequency band."

"Why does the low-frequency band receive more codes?" He asked.

"Because human voices are usually low-frequency signals, and the textbook explains the situation when telephone communication was the dominant type. But I think this has been outdated. If you want to transmit other data such as images, text, video, and audio other than voices, it no longer been suitable," I then added, "It also depends on the resources and traffic on the systems. To achieve higher quality data, more codes overall are beneficial."

The interviewer then merrily talked to the other and said, "I asked this question almost every year and this is the most special answer. Yes, it is for voices and the future trend is to transfer multimedia data over the network. He is the first one to point out that the textbook content has been out of date."

Then it was the other interviewer's turn to ask questions. He asked me to draw a diagram to illustrate the different components of a communications system, and then required me to write down the Shannon formula for channel capacity.

Then for the question about electronic circuit analysis, I answered it in three parts: linear circuits, digital circuits, and analogue circuits. For analogue circuits, I said the key was to transform the nonlinear semiconductor circuits to linear equivalents. For low-frequency signals, I said we could use parameter-based equivalent circuits. It could be applied theoretically when high-frequency signals are the inputs too, but in practice more usually, the Taylor series is applied and the higher-order components could be ignored... For the question of how to debug in software development, I said we could print out messages in the output console or set breakpoints...

After that, he asked me to explain TDMA, FDMA, and CDMA. Fortunately, I had just learned them in lectures during that semester.

"As you said, by expanding the spectrum, CDMA is good at resisting noise. Could you explain why?"

I was embarrassed and regretted talking too much about CDMA, while I was in fact not fully understanding it. Then I glanced at the paper in front of me, looking at the Shannon formula I had just written down. I said, "I don't know why for general cases, but in a special situation when the data transfer rate meets the Shannon channel capacity limit, based on the Shannon formula, if the spectrum is expanded, the signal-to-noise ratio is reduced, meaning a higher level of noise is allowed."

I thought they would be disappointed as it was almost impractical for a system to meet the channel capacity limit.

However, the two interviewers stared at me for a while and kept silent. After around a minute, one said, "Your study is very good! But why don't you continue for a master's degree?"

"If I graduate with a master's degree, I also need to find a job, right? If I can find a good one now, why do I need to do a master's degree course?"

"You're excellent!" The other said, "But our company's R&D department requires a master degree to enter. You know it is hard to ask the leaders in our Shenzhen Headquarter while you won't accept the offer in Xi'an as your hometown is in Guangdong Province."

"I think I can work in Xi'an. I really like living here," I replied.

"This is not your true thoughts," he said.

"If you now don't have any choice, would you consider a non-R&D position?" The other interviewer asked.

"The condition is meaningless," I said. "If you don't give me the offer to the R&D department, I would just go to another company."  

"Which other company do you want to go to?" He asked.  

"The one that is bigger than yours. Huawei!" I said.  

Then the interviewer said while smiling, "I mean, if you don't have other opportunities, you will still work in ZTE for a non-R&D position, right? I mean the imaginary condition, which may not be real."  

"If I were going to starve to death, I would have to accept, but as I said, this is not possible," I said.  

Then they told me the technical interview had finished and the next section was chatting with me by others, and they examined my oral English skills.