从数学家族谱（Mathematics Genealogy Project）上面可以看到：Gian-Carlo Rota 的导师是 Jacob T. Schwartz，Rota 于 1956 年在耶鲁大学获得数学博士学位，其博士论文的题目是 Extension Theory of Differential Operators。
在 1997 年，Rota 发表了两篇关于人生经验和忠告的文章，分别是 “Ten Lessons I wish I Had Been Taught” 和 “Ten Lessons for the Survival of a Mathematics Department“。下面就来逐一分享这两篇文章中的一些观点。
Ten Lessons I wish I Had Been Taught
（a）每次讲座都应该只有一个重点。（Every lecture should make only one main point.）
Every lecture should state one main point and repeat it over and over, like a theme with variations. An audience is like a herd of cows, moving slowly in the direction they are being driven towards. If we make one point, we have a good chance that the audience will take the right direction; if we make several points, then the cows will scatter all over the field. The audience will lose interest and everyone will go back to the thoughts they interrupted in order to come to our lecture.
（b）不要超时。（Never run overtime.）
Running overtime is the one unforgivable error a lecturer can make. After fifty minutes (one micro-century as von Neumann used to say) everybody’s attention will turn elsewhere even if we are trying to prove the Riemann hypothesis. One minute overtime can destroy the best of lectures.
（c）提及听众的成果。（Relate to your audience.）
As you enter the lecture hall, try to spot someone in the audience with whose work you have some familiarity. Quickly rearrange your presentation so as to manage to mention some of that person’s work. In this way, you will guarantee that at least one person will follow with rapt attention, and you will make a friend to boot.
Everyone in the audience has come to listen to your lecture with the secret hope of hearing their work mentioned.
（d）给听众一些值得回忆的东西。（Give them something to take home.）
Most of the time they admit that they have forgotten the subject of the course and all the mathematics I thought I had taught them. However, they will gladly recall some joke, some anecdote, some quirk, some side remark, or some mistake I made.
（a）开讲前保持黑板干净（Make sure the blackboard is spotless.）
By starting with a spotless blackboard you will subtly convey the impression that the lecture they are about to hear is equally spotless.
（b）从黑板的左上角开始书写（Start writing on the top left-hand corner.）
What we write on the blackboard should correspond to what we want an attentive listener to take down in his notebook. It is preferable to write slowly and in a large handwriting, with no abbreviations.
When slides are used instead of the blackboard, the speaker should spend some time explaining each slide, preferably by adding sentences that are inessential, repetitive, or superfluous, so as to allow any member of the audience time to copy our slide. We all fall prey to the illusion that a listener will find the time to read the copy of the slides we hand them after the lecture. This is wishful thinking.
多次公布同样的结果（Publish the Same Result Several Times）
The mathematical community is split into small groups, each one with its own customs, notation, and terminology. It may soon be indispensable to present the same result in several versions, each one accessible to a specific group; the price one might have to pay otherwise is to have our work rediscovered by someone who uses a different language and notation and who will rightly claim it as his own.
说明性的工作反而更有可能被记得（You Are More Likely to Be Remembered by Your Expository Work）
When we think of Hilbert, we think of a few of his great theorems, like his basis theorem. But Hilbert’s name is more often remembered for his work in number theory, his Zahlbericht, his book Foundations of Geometry, and for his text on integral equations.
每个数学家只有少数的招数（Every Mathematician Has Only a Few Tricks）
You admire Erdös’s contributions to mathematics as much as I do, and I felt annoyed when the older mathematician flatly and definitively stated that all of Erdös’s work could be “reduced” to a few tricks which Erdös repeatedly relied on in his proofs. What the number theorist did not realize is that other mathematicians, even the very best, also rely on a few tricks which they use over and over. But on reading the proofs of Hilbert’s striking and deep theorems in invariant theory, it was surprising to verify that Hilbert’s proofs relied on the same few tricks. Even Hilbert had only a few tricks!
别害怕犯错（Do Not Worry about Your Mistakes）
There are two kinds of mistakes. There are fatal mistakes that destroy a theory, but there are also contingent ones, which are useful in testing the stability of a theory.
使用费曼的方法（Use the Feynman Method）
You have to keep a dozen of your favorite problems constantly present in your mind, although by and large they will lay in a dormant state. Every time you hear or read a new trick or a new result, test it against each of your twelve problems to see whether it helps. Every once in a while there will be a hit, and people will say, “How did he do it? He must be a genius!”
不要吝啬你的赞美（Give Lavish Acknowledgments）
I have always felt miffed after reading a paper in which I felt I was not being given proper credit, and it is safe to conjecture that the same happens to everyone else.
写好摘要（Write Informative Introductions）
If we wish our paper to be read, we had better provide our prospective readers with strong motivation to do so. A lengthy introduction, summarizing the history of the subject, giving everybody his due, and perhaps enticingly outlining the content of the paper in a discursive manner, will go some of the way towards getting us a couple of readers.
为老年做好心理准备（Be Prepared for Old Age）
You must realize that after reaching a certain age you are no longer viewed as a person. You become an institution, and you are treated the way institutions are treated. You are expected to behave like a piece of period furniture, an architectural landmark, or an incunabulum.
Ten Lessons for the Survival of a Mathematics Department
不要在其他系讲自己系同事的坏话（Never wash your dirty linen in public）
Departments of a university are like sovereign states: there is no such thing as charity towards one another.
别越级打报告（Never go above the head of your department）
Your letter will be viewed as evidence of disunity in the rank and file of mathematicians. Human nature being what it is, such a dean or provost is likely to remember an unsolicited letter at budget time, and not very kindly at that.
不要进行领域评价（Never Compare Fields）
You are not alone in believing that your own field is better and more promising than those of your colleagues. We all believe the same about our own fields. But our beliefs cancel each other out. Better keep your mouth shut rather than make yourself obnoxious. And remember, when talking to outsiders, have nothing but praise for your colleagues in all fields, even for those in combinatorics. All public shows of disunity are ultimately harmful to the well-being of mathematics.
别看不起别人使用的数学（Remember that the grocery bill is a piece of mathematics too）
The grocery bill, a computer program, and class field theory are three instances of mathematics. Your opinion that some instances may be better than others is most effectively verbalized when you are asked to vote on a tenure decision. At other times, a careless statement of relative values is more likely to turn potential friends of mathematics into enemies of our field. Believe me, we are going to need all the friends we can get.
善待擅长教学的老师（Do not look down on good teachers）
Mathematics is the greatest undertaking of mankind. All mathematicians know this. Yet many people do not share this view. Consequently, mathematics is not as self-supporting a profession in our society as the exercise of poetry was in medieval Ireland. Most of our income will have to come from teaching, and the more students we teach, the more of our friends we can appoint to our department. Those few colleagues who are successful at teaching undergraduate courses should earn our thanks as well as our respect. It is counterproductive to turn up our noses at those who bring home the dough.
学会推销自己的数学成果（Write expository papers）
When I was in graduate school, one of my teachers told me, “When you write a research paper, you are afraid that your result might already be known; but when you write an expository paper, you discover that nothing is known.”
It is not enough for you (or anyone) to have a good product to sell; you must package it right and advertise it properly. Otherwise you will go out of business.
When an engineer knocks at your door with a mathematical question, you should not try to get rid of him or her as quickly as possible.
不要把提问者拒之门外（Do not show your questioners to the door）
What the engineer wants is to be treated with respect and consideration, like the human being he is, and most of all to be listened to with rapt attention. If you do this, he will be likely to hit upon a clever new idea as he explains the problem to you, and you will get some of the credit.
Listening to engineers and other scientists is our duty. You may even learn some interesting new mathematics while doing so.
联合阵线（View the mathematical community as a United Front）
Grade school teachers, high school teachers, administrators and lobbyists are as much mathematicians as you or Hilbert. It is not up to us to make invidious distinctions. They contribute to the well-being of mathematics as much as or more than you or other mathematicians. They are right in feeling left out by snobbish research mathematicians who do not know on which side their bread is buttered. It is our best interest, as well as the interest of justice, to treat all who deal with mathematics in whatever way as equals. By being united we will increase the probability of our survival.
Flakiness is nowadays creeping into the sciences like a virus through a computer, and it may be the present threat to our civilization. Mathematics can save the world from the invasion of the flakes by unmasking them and by contributing some hard thinking. You and I know that mathematics is not and will never be flaky, by definition.
This is the biggest chance we have had in a long while to make a lasting contribution to the well-being of Science. Let us not botch it as we did with the few other chances we have had in the past.
善待所有人（Learn when to withdraw）
Let me confess to you something I have told very few others (after all, this message will not get around much): I have written some of the papers I like the most while hiding in a closet. When the going gets rough, we have recourse to a way of salvation that is not available to ordinary mortals: we have that Mighty Fortress that is our Mathematics. This is what makes us mathematicians into very special people. The danger is envy from the rest of the world.
When you meet someone who does not know how to differentiate and integrate, be kind, gentle, understanding. Remember, there are lots of people like that out there, and if we are not careful, they will do away with us, as has happened many times before in history to other Very Special People.
Rota, Gian-Carlo. “Ten lessons I wish I had been taught.” Indiscrete thoughts. Birkhäuser, Boston, MA, 1997. 195-203.
Rota, Gian-Carlo. “Ten Lessons for the Survival of a Mathematics Department.” Indiscrete Thoughts. Birkhäuser, Boston, MA, 1997. 204-208.
在运维领域，服务侧的异常会由多方面的原因造成，有的时候是因为网络的抖动，有的时候是因为机器的故障，有的时候甚至是因为人为的变更。本篇博客会介绍一种机器异常定位的方法，论文是来自于清华 Netman 实验室的《FluxRank：A Widely-Deployable Framework to Automatically Localizting Root Cause Machines for Software Service Failure Mitigation》。本篇论文主要介绍了如何从服务的故障定位到局部异常的机器，也就是说在发现服务故障的同时，进一步推断出是由哪些机器出现问题而导致的。
在同一个模块下，如果出现故障机器的占比较大，那么故障将集中于这个模块下，可以通过 ratio 这个指标进行排序工作。
在 FluxRank 论文中，作者们收集了 70 个真实的案例，然后根据实验效果获得了结果。
在标记的时候，除了标记异常机器（Root Cause Machines，简称为 RCM）之外，也需要标记相关的指标（Relevant KPI，简称为 RK）。Root Cause Digest（简称为 RCD）把包括两个部分，不仅包括 RCM 的一个聚类结果，还包括聚类结果中的 top-five KPIs。
通过对 FluxRank 进行实验，可以得到如下实验数据：
其中 Recall@K 指的是： 或者
FluxRank: A Widely-Deployable Framework to Automatically Localizing Root Cause Machines for Software Service Failure Mitigation，Ping Liu，Yu Chen，Xiaohui Nie，Jing Zhu，Shenglin Zhang，Kaixin Sui，Ming Zhang，Dan Pei，ISSRE 2019， Berlin, Germany, Oct 28-31, 2019。
Introduction to Statistical Quality Control，6th edition，Douglas C.Montgomery。
从 NUS 的巴士线路图上可以看出，NUS 不仅无缝对接着地铁站 Kent Ridge MRT，也对接着 Kent Ridge Bus Terminal。因此无论从学校的任何地方，都可以通过 Shuttle Bus 到达地铁站或者公交站。不过话说回来，笔者刚到 NUS 的时候是 2010 年，当时还没有开通 Kent Ridge MRT，要坐地铁只能够去 Clementi 或者 Buona Vista，而且只能坐 95 路或者 96 路公交车出行。到了 2011 年的时候，随着修建了 6 年的 Kent Ridge MRT Station 建成，NUS 的学生们就可以很方便的出行了。
NUS 的 Shuttle Bus 是免费给所有人乘坐的，包括老师，学生，外来的工作人员等。除了免费这一个福利之外，NUS 的 Shuttle Bus 也别具特色，学校会将 LOGO 印在 Bus 上，可以让人一眼认出这个是 NUS 的 Bus。而 Bus 的大小是按照线路来分的，通常来说 A1，A2 的车型相对偏大，而 B1，B2，C 车的车型相对偏小，这也是根据是否经过宿舍区，和路线上人数的多少而定的。
在 NUS 里面，除了学校的穿梭巴士之外，还有很多其余的穿梭巴士，其中比较有名的就是 West Coast Plaza 的 Shuttle Bus 了。在 UTown 和 Kent Ridge MRT Station 还没有建好的时候，West Coast Plaza 就是 NUS 学生经常去购物的地点了。因此，免费的穿梭巴士就成为了首选。但是 West Coast Plaza 的穿梭巴士则小了许多，跟香港的小巴能够装载的人数差不多。除此之外，在 PGP 附近，笔者好像也见过 Science Park Shuttle，只不过从来就没有坐过，也并不知道这辆车的目的地是哪里。
其实 NUS 的食堂还是相对较多的，在 Engineering，Science，Business 等院系都有自己的食堂。无论是学校内的人，还是外部的工作人士，都可以选择到这些食堂吃饭。在大学城 UTown 的 Town Plaza 也有食堂，无论是中国美食还是其他国家的食物，基本上在这里都能够找到。对于数学系的博士生而言，每天到了午餐或者晚餐的时候，除了在 Science 吃饭之外，还可以选择到 UTown 或者 Prince George Park 吃饭。而每到周末或者节假日，也就只有这两个食堂开门了，其他食堂（例如 Science Canteen 等食堂）在节假日期间是不会对外开放的。在博士生日常思考人生的同时，思考每一顿饭吃什么也是一件非常重要的事情。
位于新加坡西海岸的新加坡国立大学（National University of Singapore）是一所综合性大学，近十年在泰晤士报（Times）世界大学排名和 QS 世界大学排名上，NUS 都长期名列前茅，属于亚洲的顶级学府。NUS 的前身成立于 1905 年，今年恰好是 NUS 115 校庆的年份。发展至今，NUS 已经是拥有多个学院的综合性大学，其中包括理学院（Faculty of Science），工学院（Faculty of Engineering），商学院（Business School）等诸多学院。
NUS Open Day（新加坡国立大学开放日）
学校的排名除了全体教职工的努力之外，优秀的生源也是保障学校能够持续运营的必要条件。因此，在每个学年的第二个学期，大约在 2，3月份的时候，NUS 都会开展 Open Day，目的之一就是对新加坡的本地学生和国际学生宣传 NUS。除了宣传自己的硬件设施，专业特色，教授质量之外，还会宣传校园生活（Campus Life），基础设施和历年优秀学生的就业情况。
当年笔者还在 NUS 就读的时候，就有幸参加过 NUS 的 Open Day，不过当年只是为了凑热闹而去观看了一些活动，并没有在申请学校之前就享受到这些福利。每年到了 Open Day 之际，都会有大批中学生或者理工院校的学生前来 NUS，通过参观 NUS 的情况，来判断 NUS 是否适合自身的发展。
NUS E-Open House
由于 2020 年的开局实在是不利，世界上的诸多国家都受到了新型冠状病毒的影响，自然新加坡也不例外。可能是因为这个原因，2020 年的 NUS Open Day 就从线下（Offline）搬到了线上（Online），通过网络这一个重要的媒介来开展 Open Day。今年的 NUS E-Open House 应该是历史上首次在网上举办的校园开放日活动，同时校方在 NUS 的官网上也进行了大力的宣传。
School of Continuing and Lifelong Education（持续与终身教育学院）
学习不仅仅是学生时期的事情，在这个高速发展的时代，学习这件事情将会伴随我们每个人一生的时间。于 2016 年成立的 School of Continuing and Lifelong Education 会给每个成年人提供持续教育的机会。它主要是为了想学习新技能的成年人或者想拿到学位的成年人而设置的。在这个学院有本科项目和硕士项目，还有短期项目或者各种培训。如果想拿到某些证书或者学位，其实这里是个不错的选择。
当年在新加坡国立大学（NUS）读书的时候，身边就有一些攻读 Master 学位的同学，当时他们就已经在公司工作了，在工作之余会选择 part time 的硕士在进行攻读。只要达到了学分或者做完了相应的 Project 就可以拿到 Master 学位。
Department of Mathematics（数学系）
新加坡国立大学数学系的前身可以追溯到 1929 年的 Raffles College。当时理学院开设了数学，化学，物理三门课程，不过总共也就只有十个学生和三位教师，其中有一位是数学教师。第一届数学系的领导（从1931年到1959年）是 Alexander Oppenheim 教授，他是在美国芝加哥大学获得的博士学位。从 1929 年开始，在新加坡的教育系统中，数学教育事业得到了巨大的发展，对现在的新加坡国立大学和南洋理工大学的建立起到了至关重要的作用。
随着 NUS 的建立，数学系就进入了一个新的时代。新的校区在 Kent Ridge，1986 年理学院和数学系就在这里成立。这个时候，数学系就有了巨大的发展，不仅在本科生的招生规模方面有了巨大提高，在研究生项目规模上也有了一定的深度的提升。
在本次的 NUS E-Open House 中，Science 的每个院系都提供了相应的宣传资料，并且所有学科统一模板，由各个学科的教授来向大家介绍这些专业的背景，学习内容和相关优势。在 NUS 的数学系（Department of Mathematics），则是由 Prof Tan 来给大家介绍院系的相关内容。
俗话说，数学是科学的基础。数学不仅仅是数学书上的一道道定理，而是可以解决现实生活问题的重要工具。在天气预测方向，动力系统（Dynamical System）有着独特的应用；在机器学习领域，微积分，线性代数与概率论则为这门学科提供了理论基础。在金融领域，Black-Scholes 方程，Monte Carlo 模拟则是其中的重要模型。从这些学科的发展来看，数学不仅可以为这些学科提供理论基础，也是解决这些学科难题的重要工具之一。