Adventures in Tech

I have an old Samsung ML-1210 printer  that is more than 10 years old. Despite its age, the printer is still in an excellent condition: it prints high quality PDF documents reliably albeit slowly, and satisfies my needs. But because of its age, it is hard to find a working native driver for Mac OS X, as Apple stopped supporting the printer in Lion, and Samsung stopped supporting the drivers after 2005. I could of course retire the printer, and buy a new one that is faster, and cheaper, but I tried to find another route where I continue using my old trusty printer. Luckily, one exists through CUPS on Mac OS X, by using  ghostscript, foomatic-rip, and samsung-gdi . The packages on the page are for Mac OS X Lion, but I found them to work for later versions as well. The only inconvenience of using these packages is that you have to re-install them after every Mac OS X upgrade. With the latest Yosemite upgrade,  the packages broke because of sandboxing,  where foomat...

I stumbled upon an old article from the Harvard Business Review about the making of a corporate athlete . The title lured me in; it is always flattering to compare corporate leaders to professional athletes that are admired by the masses. The thesis of the article is that performance demands on today's corporate leaders rival those on professional athletes, and while the latter get all the training and recovery and support they can before and after competing, corporate leaders do not. In fact leaders are required to perform under stress 24/7 year round with no time to recover or unwind. The article argues that unwinding and recovery are crucial for peak performance.  The article lists four dimensions of capacity that the leader needs to worry about: physical, mental, emotional, and spiritual capacities. By strengthening each of these capacities, the corporate leader can draw on the separate strengths, and manage to handle work pressure, and performance demands. The article l...

This year's modern marketing experience conference took place in Las Vegas at the Venetian hotel. The hotel, like other Vegas hotels, contains a lot of fancy stores with prestigious brands. In between the sessions, the conference attendees would walk around the stores perusing the merchandise and enjoying the luxury of the stores. One of the more eclectic stores in the hotel that attracted my attention was Bauman rare books store .  I have never seen a similar store before, so I decided to go in and check it out. The store specializes in rare first edition books and ones that are signed by the author. I was surprised to see first edition books by Charles Dickens, and John Steinbeck, as well as Winston Churchill and author famous authors. The store appeals to rare book collectors, and the prices definitely reflect that .  Despite that, the staff were very friendly toward non collectors. They were very engaging and knowledgeable about each book's history and lineage. They e...

Daniel Pink' s keynote at the modern marketing experience conference was great. In the keynote, he talked about how the world of selling is changing due to changes in information asymmetry--what information is available and to who. In the older days, the salesperson knew a lot more about the product than the consumer, and when they interacted, the salesperson had to convey a lot of information about the product to the consumer in a very short period of time. This time crunch led to the perception that sales people were pushy, fast talkers, and sometimes sleazy. The perceptions were not helped by an experiment where people were asked what was the first word that came to their mind when they recalled an experience with a salesperson. The top 25 words were not flattering. In the new world, where information is at everyone's fingertips--thanks in a large part to the Internet, and search engines--the information asymmetry shifted the other way, tipping more toward the consumers...

Another great example of randomized algorithms in the introductory chapters of the book " Probability and Computing " is verifying matrix multiplication. Suppose we have 3 matrices of compatible dimensions $A, B$, and $C$, and we want to verify that \[A\cdot B = C\] For simplicity, let's assume that all the matrices are square, and of dimension $n \times n$. The straightforward way to do the verification is to explicitly multiple the matrices $A$ and $B$ together, an operation that is of the order of magnitude of $O(n^3)$. As an aside, we can do better than $O(n^3)$ for matrix multiplication for larger matrices. Wikipedia has an excellent writeup on  Strassen's algorithm  which accomplishes matrix multiplication in $O(n^{2.8074})$ through divide and conquer. First the matrices $A$, $B$, and $C$ are padded with zero columns and rows so that their dimensions are of the form $2^m \times 2^m$. The matrices are then divided into equally sized  block matrices of the f...

Think of a search query, and go to your favorite search engine and conduct the search. Of the millions of matching documents returned, it is most likely that the first page or two contain what you are looking for. Have you ever wondered how the search engines know how to present the most relevant results for us in the first couple of pages, when all the results returned match the query we were looking for? There are a lot of signals search engines use to determine the importance of the matched results: some are intrinsic to the page such as where in the page the match occurs, whether it is highlighted or not, and the importance of the web page; and some are extrinsic such as how many users clicked on the result for a similar query. The signals, their weights, and the formulas to rank the results are usually guarded secrets by search engines as they are the secret sauce for giving users the best results to their queries. One such signal is the importance of a web page. How would yo...

We are all accustomed to deterministic algorithms; we work with them every day, and feel comfortable in knowing that the results of running them are predictable, barring a coding error of course. The idea of randomized algorithms feels remote and uncomfortable, despite their usefulness and elegance.  There are a couple of great examples in the introductory chapters of the book " Probability and Computing " that are an eye opener. One is verifying polynomial identities: how can you tell that two different representations of polynomials are the same? For example, if we have two polynomials $P(x)$ and $Q(x)$, both of degree $d$ described by the following formulas: \[ P(x) = \Sigma_{i=0}^{i=d} a_i x^i \\ Q(x) = \Pi_{i=1}^{i=d} (x-b_i) \] how can we determine that they are the same polynomial? Intuitively we first check that the degrees are the same, then we could try to transform one form into the other, either by multiplying out the terms for $Q(x)$, collecting like t...