About Simulation Techniques

The final project of my undergraduate degree, which was entitled "Multicast Switching Technologies in High Speed Routers", was supervised by Associate Professor Fan Yang. I chose him to be my supervisor as I had a very positive impression of him in his lectures on switching technologies. One day I sent him an email to discuss a statement from the textbook, which had made me rather confused. "Your understanding is correct, and the way to express the idea in the textbook is a little misleading," he responded quickly. "How would you like to do the project?" he asked me. "If you really want to do an excellent project, I can guide you to use a couple of network simulation tools such as NS2 or OPNET." "Yes, I want to try my best and learn as much as possible from it!" I said with a determined voice.

However, I soon became regretful for this. In the final semester of university, I first devoted myself to finding a job. I wanted to find an employer who could allow me to break the contract with ZTE. After many unsuccessful attempts, I had given up. Instead, I used almost all available time to prepare for taking the IELTS test, with a plan to study in Australia. After finishing the examination, it was merely a week or so before the due date of the final project. At the time, it had no longer been enough for me to learn those simulation tools. I was thinking of writing a program by myself from scratch. I wrote an email to my supervisor about the basic idea, and he confirmed with me that the basic idea was rational. Therefore, in my final project report, there were a number of pages of a C program appended, which simulated an algorithm from a paper. It was a console program without any visualization. What the program did was simulate the algorithm to calculate throughputs.

In July of 2008, when I'd just graduated, I was engaged in the training program for fresh graduates in ZTE. I was assigned to the department of CDMA network planning and optimization. In the real world, network planning typically relies on simulation as the initial step. This is because setting up a wireless network is of high cost and complicated. Many calculations are done inside the simulation tools. After the installation of network facilities, a road test is compulsory to test the signal strength in every corner of the place, and adjustments are usually needed as a later step.

In 2009, I enrolled in a course at QUT in Australia. In the second semester, I enrolled in a unit about operating systems. The virtual machine is a type of simulation which simulates the hardware from the ground up. At the same time, I was doing a project in the Microsoft eResearch Centre. The project was related to the Windows CE embedded system, where simulation was used as a tool for development.

In early 2010, I enrolled in a unit called "AI for Games", which taught computer games agent development. This was probably my favourite unit at QUT. In this unit, we explored the OpenSim platform, an open-source project written in Mono.NET. It was a Second Life simulation platform. Various algorithms had been learned during this time, with the honey bees optimization algorithm, the Mini-Max human chess competition algorithm, and the distributed behaviour models that used to model collective behaviours among the most impressive ones.

Several years later, I began to draft a thesis on the topic of "Unusual Event Detection in Crowded Scenes" in the area of intelligent computer vision. I realized that many abnormal events with security interest are impossible to obtain with a sufficient number of instances in real-world surveillance footage. "When we can't get them in the real world, how do we test them?" I wondered. Then I suddenly thought of the OpenSim simulation that I'd learned before. If the videos generated by computer graphical simulation were not looked as real enough, I thought we could also use a set of robots to simulate. While a group of robots moved together, we could apply the distributed behavior models to simulate movements in the real world. Then in the conclusion chapter, I said cross-disciplinary research, such as including simulation techniques, was compulsory in this research topic.

In 2015, I was working on a paper on resource allocation management in the area of process mining. We first used simulated data with a well-known ground truth to evaluate the algorithm in ideal conditions. Then we applied it to a real-world dataset, and verified it with business feedback. Professor Wil van der Aalst, who was the "father of process mining", had given the section I drafted very positive comments, which I had been very proud of until now.

However, I do believe simulation is overused in telecommunications engineering research. I've read many papers in these areas, and many of them only have simulation-based results. I've always considered those papers as incomplete. "When are you going to start simulation?" Professor Huang urged me when he was pushing me to have a paper in pattern recognition, where simulation was rarely used, when I was working in Shenzhen University.

In around 2020, I started some development for mobile applications. Simulations for different models of mobile devices were used extensively to develop mobile apps on a desktop computer.

My University Roommates

The summer of the year 2008 was full of both amusements and anxieties. I knew that I had been deceived by ZTE but I couldn't do anything to change the result. The study in the final semester of university was rather relaxed, as we only needed to finish the final project, which everyone would be able to pass, whereas we couldn't get the highest rank no matter how well we did, as the highest rank had to be given to those who would continue to study postgraduate studies at the same university, which was a ridiculous policy. Games, dinings, parties, and various farewell activities had fulfilled the life of a student at this time. I was not sure when I would be able to meet those who lived with me in the same room for four years once we departed from the campus.

The time in ZTE passed quickly, as every day I would be heavily engaged in the training organized by the company for fresh graduates. I didn't realize the days would be that hard to spend after I quit the job.

I missed the many nights I chatted with roommates on bed until falling asleep. We shared many experiences in life. While they were jealous of my family background as I had a grandma living in Australia and they sometimes said I would go to Australia sooner or later, I was in my deep mind jealous of those who grew up in the countryside. In my blurred memory, I had longed for the natural world since my family moved to the urban area from a rural village when I was still a toddler. Chen Chao said his hometown was surrounded by mountains and there was a river that many students had to swim across to go to school, which sounded like the most romantic style of life to me. Many a time I urged Liu Zhengqiang  to ring the phone number of the dormitory opposite to ours, only to get some excitements when hearing someone from Room 317 get up to answer the phone while the call suddenly stopped. Most of the time, Mo Can was silent. But suddenly he would utter one to two wonderful ideas that impressed others to remind us for his existence.

I missed the many days we went to classrooms together, we went to library together, we mischievously peed in the bush on the river bank together after dining out, we fought with each other with snow balls in winter, and we played in the swimming pool together in summer when Zhang Dehao pushed me to the pool unexpectedly only envying I could swim. They didn't believe I could speak Cantonese simply because I had been seldomly interested in pop music from Hong Kong until one day I sang a piece of passage from a famous Cantonese opera in a KTV, which had made them startled.

In the several months after leaving Xi'an, I often thought of the old days and was eager to know how others were. It seemed that I was just on a holiday that was longer than a normal summer vacation rather than having permanently leaving Xi'an. I occasionally felt a bit regretful to leave Xi'an too early, but if I continued a postgraduate course there, many of my friends had departed and lived elsewhere. 

“Are they talking about me?" I wondered. "Do they still remember me?" I wondered. "Do they know I am under huge pressures?" I didn't wonder, as I knew they weren't. They envied me for studying in Australia but they didn't understand the pressures I was suffering. They had always thought of me growing up in a very rich family, and they couldn't believe that every step I'd taken was in fact full of challenges. 

One day in a forum of our university, I read an anonymous post about a fresh graduate's half year's experience in a small, non-capital city in Sichuan Province. "Is it written by Chen Chao?" I wondered. Not sure why I would think it was written by Chen Chao, as it really didn't expose the author. However I did have a feeling from the way of narrative that it must be written by my roommate Chen Chao. I was mostly impressed that the article mentioned that one of his very good friends had gone overseas, making him rather lonely. "Am I the one overseas? His very good overseas friend must be me."

Time passed fast. Several years had been passed before I had the opportunity to meet one of them. In December of 2016, more than eight years after our graduation, I met Mo Can again in Shanghai. Despite he still remembered and was concerned about me, he'd lost ideas about many topics I discussed with him, including academic life, Australia, and immigration. I had felt the distance between us, despite the Shanghai gathering was the best among all that I met my old classmates! I met a few friends from Room 317 in Hangzhou, and felt rather disappointed with the coolness.

In 2017 I returned to China to work for a year and a half. In 2018, unexpectedly I met my French roommate Zhang Dehao and my Hebei province roommate Jia Chenggang. I had to confess that there had been a wall among our minds. The wall was caused by time and physical distance. I then realized that I was even more comfortable with two of my closest Chinese friends in Australia, as at least we could understand each other's lives better.

Classmates from our dormitory room have set up a WeChat group. At first we had discussions regularly. However, as time passed, I found my mind had become more and more distant from theirs. Eventually I decided to quit, as I had been tired of arguing with them.

Friendship is always unable to fight with time and distance, no matter how close you once were!

My Little Sketch Book

I have a sketchbook that is so small that I can even put it into a pocket, and as a result, I can easily carry it everywhere and sketch whenever I am interested in something in my view. Last year, when I resumed my hobby as a painter, I typically started painting from photos. However, I later found it a very bad idea. The photos contain too much useless information, while they often miss those important details. Through this process, I could understand in depth that photos are very different from paintings. Later, I found that fine art paintings from rapid sketchings from life are a good approach. That is, we first use a pen to rapidly draw when we are physically on the scene, then when we have time and settle well at home, we can paint a bigger picture with more details and in a more finished style.

I switched a few types of sketchbooks and eventually narrowed the small one. If we are going to sketch a complicated view, we can separate the view into a number of sketches. When we paint the full picture at home, there is a process to composite them into a single picture. I think this a suitable way for me to create art works.

From then on, I put my little sketchbook in my handbag. Whenever I am boring or see something interesting, I will use a ballpoint pen to sketch one to two pages. Gradually I found that life is full of curiosities, full of excitements, and full of hopes.

Shorncliffe Pier

 My wife had addressed the two boys again and again for not going too far away, as they would be tired and probably were not able to return back to where we parked our car when the brothers were riding a bicycle and a scooter. However, the brothers ignored her summon and rode as far as they could to Shorncliffe Pier.

Shorncliffe Pier was a wooden bridge that stretched from the shore to the middle of the ocean for tourism and fishing. There was a fishing group holding an activity when we arrived, and thus it was very crowded, with fishing rods leaning on the fence. As usual, there were also some people coming for leisure. A few of them were leading dogs, while some others were pushing baby prams. What a peaceful and pleasant view!

At the end of the pier was a pavilion with a white roof. It was very enchanting when viewing it from far away, just like a small white cottage floating on the ocean. It was a beautiful, sunny Saturday, with golden sunshine gleaming on the waves, which was more astonishing and splendid than any painting that was possible to create. I liked to hold a cup of coffee while leaning on the fence and listening to the ocean waves and winds, as well as feeling the warmth in the golden sunshine.

Shorncliffe Pier was one of our most frequently visited spots. When I came to Brisbane for a course at QUT, it was just a small, ragged pier, much shorter than the current one, despite the surrounding area being the same beautiful. I am not sure from which year on the current pier has been built.

When I had finished a contract with QUT and before the start of a new job at Shenzhen University, I often drove here with my parents. We tried fishing like others but couldn't catch any. Nevertheless, it fulfilled the days when I was rather dreary.

In recent years, when we came here, we had seen a couple of spectacles. One day we played here until dark and saw a full moon rising from the horizon of the ocean. On another day while there, it was raining. Then we could see a giant rainbow across the sea.

Jacaranda

On an early day of this school holiday, we went to New Farm Park. "I think we should admire the jacarandas, as spring has arrived," I suggested. 

My wife reminded me, "I'm afraid there will still be some days before the peak."

 I said, "Well, I have to agree with you, but it will be a pity if we wait for them to bloom and there's a heavy rain before we go there. So, I think we'd better go there today and we may visit again in a few weeks."

When we arrived at the park, we saw that a few jacaranda trees were blooming while others were not. "It is so interesting that the purple flowers are concentrated on a few trees," I said to the boys.

There's a pedestrian and cyclist shared path along the Brisbane River. The two boys merrily rode their bike and scooter there. We went across a few spots with blooming bougainvilleas, which decorated the riverbank greatly.

I saw a jacaranda tree standing next to a metal fence, with purple flowers flourishing on the branches. Inside the metal fence was a quiet garden with a bench just underneath the jacaranda tree. I then imagined to be the owner of this quiet garden, sitting on the bench under the jacaranda tree and leisurely seeing the purple petals falling to the ground. This gave me the inspiration to paint the watercolour painting called "Jacaranda" recently.

Not long after that, the boys became tired. It was too hot to do sports, even though summer hadn't come yet. On the way home, I agreed with the boys to purchase a couple of bags of seeds to grow flowers in the garden.

Ocean Views

I am grateful to live in the northern suburbs of Brisbane, as it is so convenient to go to the seashore. In the old days, when I was living in Indooroopilly, it was not that easy.

As the warmer season has arrived, we’ve resumed our activities at swimming pools. Despite living close to the Chermside swimming pool, we are keen to travel a little further to the Sandgate Aquatic Centre, which is located on the shore. Next to it is a café with great ocean views. My wife enjoys holding a cup of coffee and taking photographs.

The weather was not good yesterday, but as painters usually believe, bad weather can be more beautiful. When the sky was overcast and the trees were shaken fiercely by winds from the ocean, the view was naturally like an ink and wash painting. Though there was a big umbrella covering our table when we had lunch in the café, we still got wet during a shower, as the winds blew the rain at us from all directions, making it impossible to escape.

After lunch, the two boys — one riding a bike and the other riding a scooter — were chasing each other on the path along the seashore. The tide had receded a great deal, leaving a soil beach that was wet and mostly covered by shallow water. It was interesting to see water birds wandering leisurely on the beach.

The trees on the shore were very special. Having experienced winds and rains from the sea, they had grown into shapes and forms that we typically couldn’t see elsewhere. They stood on the shore like some most delicate statues, crafted by Mother Nature.

In a few spots on the shore, we saw strange rocks. Occasionally, there were crabs hiding on the rocks.

I will never get tired of ocean views. Different places on the shore have different spectacles. They are different at different times, under different weather conditions, and in different seasons.

My International Friends - 2

 In the second semester of 2009, I was enrolled in a unit called "Enterprise Software Architecture," which is probably the most influential unit to me. The second assignment was to work in a group to develop a service-oriented architecture system. My Vietnamese friend, my Malaysian friend, and I formed a group. Every late afternoon, we would gather together to do the assignment. Our Vietnamese friend was very good at C# and became the main developer for the C# component. I took charge of the Java component, and our Malaysian friend focused more on the report as his English was the best among the three of us. When we were tired or hungry, we would go to Queen Street to buy food for dinner. Besides studies, we had lots of conversations, which allowed me to know much about life in their countries. I was very grateful to know them in my first year after arriving in Australia, as they gave me a strong feeling of friendship after I left my homeland.

We almost got full marks on the assignment, and my Vietnamese friend said it was like a miracle as too many of his friends failed the unit. This excellent academic performance directly led me to the opportunity to work for C-YAWL in the BPM team with Marcello, who was from Italy and had just got his PhD degree earlier that year. I'd heard many times that he was the best PhD student QUT ever had in this area. The main reason for me to choose to work with him for a project was that he still didn't have any research students. I thought it was more likely to be able to do a challenging project with him. I had a very good impression of him in the unit, as whenever I raised a question, he could answer it clearly and rationally. Many years later when I joined the BPM team again, I often felt it a pity to not be able to work with Marcello, whom I viewed as more of a friend than a teacher.

During the summer holiday, I stayed mostly in the office of the BPM team on Margaret Street. I made a few friends, including an exchange student from Tsinghua University and a PhD student under Arthur from Iran. I was very unfamiliar with the culture in Iran. However, through sincere conversations, we could still communicate. It was then that I realized that problems in an individual's life are typically quite similar, no matter where we are from. He wanted to do research as he felt proved to himself if he could solve tough problems. However, he felt it too hard to progress in his research, putting him under huge pressure. In addition, he still couldn't win Arthur's trust to provide him enough financial support. I could fully understand his dilemma.

The start of the first semester in 2010 was rather melancholy. My Vietnamese friend and Thailand friend had graduated. I almost couldn't find them anymore on campus. Except one day I saw a familiar back view—my Thailand friend was photographing on campus. He said he'd got a job and used half a year's earnings to buy a camera.

My mind was rather disturbed during that period under financial pressures and anxiety due to immigration policy changes. Moreover, my scholarship to the SAIVT research group was said to have failed. "Is it really that competitive? I don't imagine who can get the scholarship when you can't!" Marcello said when I told him. "Two students from Sri Lanka just joined the lab." I said, "I think I've lost to them."

To make myself happier, I enrolled in a unit called "AI for Games," which was lectured by Rune for computer games' agent development. Most students in this unit were in the major of computer games, and they really liked what they were studying. "In fact, you're hard-pressed to find a job in the computer games industry!" Rune frankly said, "But you're most likely to get a job in other related areas like simulation or computer graphics." I asked my Malaysian friend whether he was worried about a job. "Not at all. If only one in the class can find such a job, I will be that one." He's always optimistic, and this was why I said I would be happier to study with him.

One afternoon, I entered the BPM team's office to submit all materials to Marcello. He was in Arthur's office. I heard Arthur blaming him with his fluent English in a bit of a Dutch accent. "Do you know how important this work is? You should give the project to a PhD student rather than a master's degree student by coursework!" Arthur said. "Arthur, but he's excellent. He's more excellent than any PhD student in the team," Marcello said. "I know he's excellent. I can't disagree with you on this point. But this is not your paper. It's Wil's!" Arthur said.

I then knocked on the door, and Arthur's face suddenly smiled merrily when I came in. I told him that if they found any issues in the codes I submitted, I would still try my best to fix them. Under Sridha's plan, I enrolled in a unit for signal processing and image processing. I grouped with two students for the assignment: one of them was from India, and the other was from Saudi Arabia. The student from Saudi Arabia often asked me to tutor him. Then later he said I was his friend. "Do you want to migrate to our country?" he said. "No," I refused politely. "I don't think I can master your language that easily."