Why writing this blog post Many UIUC students rely on the Delta to access the GPU resources for their research. Delta provides 4 ssh-enabled login nodes, and lots of computing nodes with GPUs. Usually, we must ssh to the login node (by password and DUO 2FA OTP) first, and then use srun to request GPU resources to run our code. However, based on my experience, sometimes we could suffer many problems when using the Delta: ...
Preface IPv4 has only one method of dynamic address allocation, namely DHCP, but IPv6 has two allocation methods, SLAAC and DHCPv6, and DHCPv6 additionally has the PD (Prefix Delegation) extension. These three allocation methods also interact with each other, which makes problems arising during IPv6 allocation far more common than with IPv4. Most tutorials you can find only solve problems superficially, are ambiguous about the underlying technical details, and do not fundamentally clarify the differences between IPv6 and IPv4. ...
The Problem Now we have an image representing a graph, as shown in the figure below: Suppose we already know the category of each pixel: background, node, or edge. How can we extract the graph topology from it and represent the graph by an adjacency matrix? Challenges in Classical Algorithm TODO What about Neural Network? We can use a simple algorithm to extract the position of each node. Suppose the position of a node is $\mathbf{P}(x,y)$, and there are $N$ nodes in total. ...
Motivation A machine learning cluster needs a secure way to expose services to users, as well as to interconnect servers across the public network. For this, a VPN network needs to be deployed. Deploying a VPN network requires considering the following factors: Network topology: an appropriate topology must be chosen to minimize latency as much as possible; User management: it should be easy to add or remove users and to authorize them; Simplicity of use and maintenance. Design Network Topology The network topology determines the latency. ...
This is an unfinished blog. Preface Due to Internet censorship in China (known as GFW, Great Firewall, 防火长城), many websites (e.g. Google, Twitter) are blocked, and some websites (e.g. GitHub) suffer connectivity issues. In China, the means to circumvent internet censorship is referred to as 翻墙 (means climbing over the wall). In China, to freely access the Internet, a proxy is essential. Despite various commercial options available, they may not be suitable for everyone. Therefore, I have constructed a user-friendly and easy-to-maintain proxy system for my research group, as a part of my responsibilities as a system administrator. ...