Create a visually compelling ideogram for a poster advertising a lecture on artificial intelligence. The ideogram should symbolize the concept of AI, incorporating elements like a digital brain, circuit patterns, or a humanoid robot outline. It should be simple yet striking, using a modern and technological aesthetic. The colors should be cool tones like blues and greys, suggesting innovation and intelligence. This ideogram will be the focal point of the poster, aimed at attracting academics, students, and tech enthusiasts to the event.