Chip's Technical Blog

Tech commentary of thoughts, challenges, how-to's, and the mundane.

Archive for December, 2011

NSDI 2012 Paper Accepted: Distalyzer

Wednesday, December 14th, 2011

So I learned last night that our submission to NSDI was accepted. It described the methodology for a tool we built which we can Distalyzer. Distalyzer works to help developers diagnose performance problems in their systems. It works by utilizing a minimal amount of structure from the logs, and then doing two kinds of analysis (t-tests and dependency networks) to discover the most relevant and most divergent aspects of groups of log instances. We have used it to find bugs in Transmission and H-Base, and applied it to other another system’s problem (TritonSort) to show reductions in effort needed to diagnose the problem.

Soon there will be a blog post at our research group website which describes it in more detail, but I wanted to go ahead and post about the good news.

Recent Security Papers

Friday, December 9th, 2011

So in research progress, we’ve recently published or had accepted two conference papers in the area of distributed system security. The first is a paper called “Removing the Blinders”, with co-authors David Zage and Cristina Nita-Rotaru. The basic insight of the paper is that in many protocols, nodes make decisions about other nodes based on just the last message they got from them. This is a kind of “blinders”, hiding other information the node has about the other nodes, which prevents them from making smart decisions about the peers based on the holistic information available.

However, the effort required in the first paper is totally manual. Discovering the set of attacks, and then finding the defenses for those attacks is takes a smart person thinking about it for a long time. We next set out to solve part of the problem – discovering the attacks. We focused on a restricted set of systems—those implemented in a structured language such as Mace. By applying a greedy state space exploration search strategy, we can discover a class of attacks that cause poor performance in systems. This work was accepted to NDSS 2012, about a tool we call Gatling.

Meanwhile, part of our current research involves further generalizing this work.

A real-foods diet

Friday, December 9th, 2011

So over the last several months, I’ve been working at losing weight. So far, I’ve lost about 26 pounds. My diet?

  • Less Soda. I started out by cutting back to 1 every other day. Now it’s more like 1 every once in a while. (i.e. 1-ish a week). If you figure I was having 1-3 in a day, that’s basically a drop of 150-450 calories a day, without replacement. In the place of the Dr Pepper, I’ve been mostly drinking water. I’ve also cut out my morning juice, for the most part, after being convinced that juice provides a lot of sugar/calories and not a lot of nutrition.
  • Eating products that are less processed, and more whole. This means reading ingredient lists. If there are a bunch of ingredients I don’t recognize, probably not a good sign. Most recently, this meant buying regular, all-natural sour cream rather than the fat free sour cream. When I stopped to look at the ingredient list of the sour cream, it had many, many ingredients as compared to the regular sour cream, including cellulose, which is basically the same thing as paper or wood pulp as I understand it. We just ate stroganoff made from the regular sour cream, and WOW was it good! So basically, while I’m losing weight, I’m eating richer, tastier foods, and feeling less hungry.
  • Accepting that my body had no clue what full and hungry meant. This can be attributed to many things, including the over-eating I was doing and the highly processed foods, especially the “light” foods I was eating which were essentially training my body that food did not correlate with calories. There were nights that I would make dinner portions for Kristina and I, and we would be eating, and she would remark how she was full and should stop. I would have been quite content to keep eating, but would follow her lead, and assume that what I had eaten was enough to fill me, so I would stop. I’m still not quite there, but I have started to be able to recognize sometimes in the evenings when I’m not hungry so that I opt not to snack because I’m not hungry rather than just the fact that intellectually I know I don’t need more food (which is still more common).

On the down side, one of the things we did as part of this movement was to visit our local dairy and buy a set of local cheeses. Tasty, yes. (Not necessarily more whole than what we could get at the store, but buying fresh/local is still something I’ve been doing as part of this general movement). Anyway – this morning we learn that the cheese we ate/bought while there is subject to a voluntary recall due to possible bacterial containment with a 3-70 day incubation period. Oh well.

One resource I have really enjoyed using for this is Fooducate. I enjoy both following their blog, and using their iPhone app to scan products to find out tidbits of things I ought to know.

Since I’ve been doing so much reading about food, I find I may post more about it too, so I’ve created a category for food.

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