Bulletin No. 1, 2021

THE NEW GOSPEL ACCORDING TO A.I. 15 learnt about the chosen style. And as its name suggests, this feat is made possible by AI, which could only have run on the powerful GPUs that we have been blessed with over the past two decades. Having both the intelligence and the hardware, computers are ready for a bigger role in making art, especially manga. ‘It’s such a labour-intensive craft,’ said Professor Wong of manga production. ‘Everything from the writing to the visuals will have to be taken care of by the artist and, if they are lucky, a few apprentices, oftentimes by hand.’ Automation is theoretically possible without AI, but then for each task there will have to be a tailor-made algorithm, and each algorithm will involve a number of parameters that must be manually tuned. With AI, which can learn its own parameters and adapt to different problems of a similar nature, parts of the labour can finally be delegated to machines, one example being precisely colourizing black-and-white comics. ‘There was a semiautomatic approach, where the artist would throw in dashes of colour and the computer would build on that. Then came our AI-based solution,’ said Professor Wong. Their model involves two stages in its initial form. At first, the computer is trained to recognize the black-and-white texture and remove them, leaving only the outlines; at the second stage, it learns what colours and shades are normally used in different situations, say for human skin and hair, and fill the outlines accordingly. In a later iteration, the model performs the task in one go. The artist can provide the model with hints for better results, but even without human guidance, its performance is still quite acceptable. IN MUSIC, THE USE OF AI HAS ALSO FLOURISHED. As it in visual art, the dream of automation in music has a long history. ‘Attempts at having computers make sounds began as early as the invention of computers,’ said Dr. Chau Chuck-jee of the Department of Computer Science and Engineering, who teaches the first undergraduate course on computer music at CUHK, and himself studied music here alongside computer engineering. In 1951, Alan Turing’s Ferranti Mark 1 played a snippet of God Save the King for a BBC recording crew, making it the first piece of computer-performed music on tape. In the decades that followed, researchers moved on to exploring ways of making computers write music. Earlier proposals include knowledge-based systems, where experts essentially taught the computer music theory. But as we have seen, writing out the rules are as taxing as it is for us to compose music entirely by hand, if not more. Also, these programs lack general applicability. Thus came the more robust solution of machine learning. ‘With better hardware after the AI winter at the end of the last century, there was renewed interest in machine- learning approaches to computer music,’ said Dr. Chau. Many of these approaches involve what is known as a neural network, a systemmodelled after the human brain. Given a large enough database—one that covers, say, the entire Western classical music canon—the network can work out using statistics the norms of music composition or the recurring features in the works of a particular composer. Using this knowledge, it can make new music or imitate a certain composer. Programs employing this technique include AIVA, a Luxembourg-developed virtual composer registered at SACEM, the French association of music writers, and granted copyrights. Another example is DeepBach, a model that writes chorales in the style of Bach given the soprano part. ‘The researchers brought in a number of people with different levels of musical knowledge and played a series of compositions by DeepBach. On average, around half of them thought that they were really by Bach,’ said Dr. Szeto Wai-man of the General Education Foundation Programme, who also specializes in computer music and has been involved in promoting public understanding of AI. As Dr. Szeto reported, the model does occasionally deviate Dr. Chau Chuck-jee Department of Computer Science and Engineering