Faculty Profile

Professor: Computer Science, Graduate School

Yamin LI

• Ph.D (Computer Science)

Research area:

• Computer Architecture
• Parallel and Distributed Systems
• Mobile Ad Hoc Networks

Related site:

• http://cis.k.hosei.ac.jp/~yamin/

Personal Statement

　After I got my Ph.D degree in the field of computer science, I became a university’s instructor. Since then, I developed a simple square root algorithm and its VLSI implementation. My square root implementation is the simplest and lowest at cost in the world. I published this research result in ICCD (International Conference on Computer Design - VLSI in Computers and Processors). Now, many IC chips and prototypes use my implementation. I also proposed a new topology of an interconnection network, called Dual-Cube, and many researchers are doing their research on Dual-Cube network.

Teaching Courses

Research Area

Research Motivation

"CPU design is interesting"

When I was a student, I was interested in computer architecture and CPU designs. After the graduation, I focus my attention on the performance improvement of CPUs and parallel computer systems. I feel that this kind of research is interesting.

Metacube - A New Interconnection Network

The modern high-performance supercomputers consist of hundreds of thousands of CPUs. In the near future, the number of CPUs in supercomputers will reach to several millions. How to connect these extremely large number of CPUs is an important issue for achieving high performance of the supercomputers. A Metacube is an interconnection network that can connect extremely large number of nodes while keeping the diameter of the network short and the routing algorithm simple. For example, a Metacube network with 6 links per node can connect 134,217,728 nodes. We are investigating the properties of the Metacube network and basic communication algorithms.

Efficient Broadcast Algorithm on Mobile Ad Hoc Network

Mobile ad hoc networks (MANETs) refer to a form of infrastructureless networks connecting mobile devices with wireless communication capacity. Each node in MANETs behaves as a router as well as an end host, so that the connection between any two nodes is a multi-hop path supported by other nodes. In MANETs, the multicast support is critical since the close cooperation among team members is required for many MANET applications. Multicasting in MANETs faces many challenges due to the continuous changes in network topology (mobility) and the limited channel bandwidth. Overlay multicast protocol constructs a virtual mesh spanning all member nodes of a multicast group and employs standard unicast routing to fulfill multicast functionality on application layer. We propose a specific path, called tree trunk, for the overlay multicast on the virtual mesh. A tree trunk is a path that minimizes the sum of the distances of all vertices to the path plus the length of the path. The tree trunk significantly reduces the cost for the maintenance and provides higher stability under the mobile environment.