We have a nice mix of white and black tulips. They really stand out:

I also have a nice rhododendron. I never water it or care for it in any way, and here is how it rewards me:

I do not claim to be an expert at reviewing academic papers, but I have done my share of work. Here is my recipe:

• Reproducibility, (self-)plagiarism and presentation are easy to evaluate and I usually spend quite a bit of time on these issues. Science should be reproducible. (Panos Ipeirotis seems to agree with me.) Plagiarism can be surprisingly hard to detect, but it is also amazingly frequent, so I usually search for a few word cooccurrences in Google. Presentation is, on average, quite poor. Figures are often ugly. Poor English is frequent.
• The relevance and strength of the paper is something I usually have an opinion about. Alas, it is easy to be wrong about the importance of a paper, so I usually do not have much to say unless I have directly worked on the same problems for a couple of years.
• Correctness is hard to check especially if I am not a domain expert. I usually pick up on secondary details. Are the results credible? Do the authors mention some special cases that should have arisen in their analysis or experiments? I must unfortunately admit that I usually cannot be sure that the papers I have reviewed are correct. At best, I can voice an opinion about their credibility.

If you are running MacOS and use the Safari browser, I suggest you have a look at Shiira. It uses the same underlying engine (WebKit), but provides a superior skin.

Stephen Downes prepared a Montreal photo set. The photo set is worth a visit if you want to know what Montreal feels like.

I am the nerdiest of the two:

Since I moved to the Montreal suburbs, I have become an active gardener. I used to apply generous amounts of fertilizers. I also got into serious trouble. My lawn died. Not because I burned it, but because I got a bad case of grubs. Several of my perennials died also or fail to come back healthy after the winter. I learned the hard way that most perennials are better off without any (chemical) fertilizer.

It turns out that in most cases, chemical fertilizers are overrated. As a rule, you should not use them.

• Fertilizers may contain toxic material which stays in your soil and your vegetables.
• Fertilizers may increase the acidity of the soil, which is bad for most plants.
• Fertilizers make your soil poorer, not richer over time.
• Fertilizers tend to kill the microorganisms in your soil, rendering natural composting difficult.
• Fertilizers make your plants less resilient to disease and drought: artificially sustained growth is not always a great idea. Are you really in a hurry or do you want more robust plants?

In academic circles, there are intense platform wars. We have a talk next week from the head librarian about offering Google-like services, but on an academic platform. I won’t go to the talk because I no longer care about library portals. Regarding courseware, there are wars between Moodle and other hybrids. As a professor, all that I care about is to have some tools to post content online, conveniently. The last thing I want to do is live within a monolithic proprietary platform.

Everyone is fighting for his platform. What a tragic mistake! In 2008, only one platform matters. No, it is not facebook, nor Windows Vista, nor Moodle, nor Dot.NET. It is the Web. In some sense, the Web is the platform to rule them all.

Something deeper is going on as well. In Death of the software application, I argued that software as a discrete quantity was finished. How many software applications do you run right now? Nobody cares. Similarly, the term platform is obselete: people hook up the software they need dynamically.

If someone asks you to pick a specific platform for a project, refuse to do so. Pick software the way a taylor will pick fabric: a little bit here, a little bit there. Also, if you are building a Web platform, please stop right there. Turn around and rethink your objectives.

Since I have had amazing luck in the past with questions to the readers of this blog, I have another question.

The diameter of a graph is the longest distance between any two nodes. The degree of a node is the number of edges or links from and to this node.

Intuitively, the higher the node degrees, the denser the graph. If you have n nodes and the maximal degree of the nodes is n-1, then the graph diameter is 1. If you have lesser maximal degrees, then you can get an infinite diameter by producing a disconnected graph.

An interesting question (to me) is:

Given a maximal node degree, and a number of nodes n, what is the smallest possible diameter?

I am sure this is textbook material, but I could not find the answer quickly. Using a hyper-rectangle, I am able to construct a graph having n nodes and log n diameter. Simply start with a 4-node rectangular graph: you have 4 nodes and a diameter of 2. Move to a 8-node cubic graph: you have 8 nodes and a diameter of 3. Generalizing this construction, you have 2^d nodes and a diameter of d. Is this the best you can do?

Anyhow. Why do I care about the answer? Because I keep reading that hubs are necessary in graphs to ensure that we have a small diameter. I am trying to quantify this statement. There are about 2³³ human beings. By my construction above, if everyone knows 33 people, then it is possible to get a diameter of 33. It seems like a relatively large diameter.

An obvious technique to shrink the diameter without using hubs, is to increase the maximal node degree. I am wondering by how much I need to increase the maximal node degree so that I can a 6 degree of separation between any two human beings.

(Yes, I know that social networks are not homogeneous. But stay with me. Assume they were.)