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: ...
序言 IPv4 只有一种动态地址分配方式，即 DHCP，但 IPv6 就有 SLAAC 和 DHCPv6 两种分配方式，同时 DHCPv6 还存在 PD (Prefix Delegation) 的扩展。这三种分配方式之间又存在交互，使得 IPv6 分配过程中出现的问题远比 IPv4 多。大多数可以搜到的教程只从表面解决了问题，对于其后的技术细节模棱两可，而没有从根本上厘清 IPv6 与 IPv4 的差异， ...
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 机器学习集群需要一个安全的方式向用户暴露服务，以及跨公网服务器互联，为此需要部署 VPN 网络。 VPN 网络的部署需要考虑如下因素： 网络拓扑：需要选择合适的拓扑结构以尽可能降低延迟； 用户管理：可以方便地进行用户的增减和授权； 使用和维护简单。 Design 网络拓扑 网络拓扑决定着延迟。 ...
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. ...