• Optimisation part 2: Hill climbing and simulated annealing

  In the previous article I introduced optimisation.  In this article I will go into two optimisation algorithms – hill-climbing and simulated annealing.  Hill climbing is the simpler one so I’ll start with that, and then show how simulated annealing can help overcome its limitations at least some of the time. Hill climbing To explain hill climbing I’m going to reduce the problem we’re trying to solve to its simplest case.  Imagine that you have a single parameter whose value you can vary, and you’re trying to pick the best value.  For instance, how long you should heat some bread for to make the perfect slice of toast, or how much cayenne to add to a chili. You can then think of all the options as different distances along the x axis of a graph.  How good the outcome is for each option (each option’s score) is the value on the y axis.  As I said before, this is the simplest it can be: problems can easily have many more than one dimension, but it’s hard to visualise an N-dimensional space on a 2D screen. Imagine that the graph you get for your example looks like this: Remember from the previous article: we can’t assume that there’s a nice equation that relates the x and y values, so we can’t take short-cuts such as differentiation or factorising.  I just happen to have picked a parabola because it’s easy to produce. With hill climbing what you do is: Pick a starting option[…]

  18.08.2019 | 5:31 קרא עוד...

• Let's Go Deep! Part II: Encryption, Tokens, and Cookies

  In last week's post, we talked about how HTTP works to pass information from a server to a browser.  But when information is passed back and forth between systems, we need to make sure that it's protected from being intercepted by others for whom it was not intended.  That's why HTTPS was created.  In this week's post, we'll talk about how encryption is used in HTTPS, what the difference is between cookies and tokens, the different types of cookies, and how cookies can be protected.How HTTPS Works:When two systems communicate with each other, we refer to them as the client and the server.  The client is the system making the request, such as a browser, an application, or a mobile device, and the server is the system that supplies the information, such as a datastore.  HTTPS is a method of securely transmitting information between the client and the server.  HTTPS uses SSL and TLS to encrypt the data being transmitted and decrypt it only when it arrives at its destination.  SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are both tools for the encryption and decryption of data; TLS is a newer version of SSL.  Here's how TLS works: before any data is transmitted, the client and the server first perform a handshake.  The handshake begins with the client contacting the server with a suggested encryption method and the server responding back agreeing to use that encryption method.  It then continues with the client and the server swapping certificates.  A certificate is[…]

  17.08.2019 | 9:46 קרא עוד...

• Business cards are dead

  Yeah, I'm equally surprised to get to know this. It will be quite disheartening to learn that business cards were no longer useful - A sad story!I was at TESTCON 2019 Bangalore on Test Automation. It was a premium software testing conference organised by Clavent Technologies.Many CEO's, entrepreneurs, limelight testers across the globe volunteered to confer with budding testers. Testers from various organizations like Accenture, Microsoft, Hotstar, Techmahindra, Comcast India, CSS Crop, GE, Qapitol QA, Matryxsoft Tech, WinVinaya Infosystems, Taqanal Energy, Xebia, Author Renu, Moolya Testing & AppAchhi spoke so well at the conference. It was indeed a great conference. I was very happy to confer with interesting people post conference during break time, as well. That's when I got introduced myself to participants who attended the conference. Luckily I had carried my business card so I gave it to couple of participants who attended the conference. It was all good until I saw my own business card in the dustbin :(I always love carrying business cards in my wallet. Needless to say it was an amazingly designed business card. I was told that business cards are essential tool for marketing. If so, then why it was not noticed? was it so ugly? to get thrown in dustbin?Why my business card failed to grab attention? It definitely informs others who am I? What do I do? How I can be of help? How can someone contact me? I was pondering why there is no life in printed paper cards? Just[…]

  16.08.2019 | 11:41 קרא עוד...

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