VISA application and my visit to Shozilla in Los Angeles

My USA VISA application was successful and I will be flying to Los Angeles for two weeks.

Motley Fool and stock market investments

I am studying how to invest on stock exchange. I began my journey by reading a book Motley Fool -> Online Guide to Investing.
http://www.amazon.co.uk/Motley-Fool-Fools-Online-Investing/dp/0752218107/ref=sr_1_2?ie=UTF8&s=books&qid=1210504071&sr=8-2

Having read that I am reading now
http://www.amazon.co.uk/Motley-Fool-Investment-Workbook-Books/dp/0743229983/ref=sr_1_5?ie=UTF8&s=books&qid=1210504071&sr=8-5

This book is supposed to teach me how to evaluate financial position of the company. Learn how to interpret various metrics for quantative analysis and teach some obvious things happening on stock exchange. I have read half of the book and so far I must say half of it was childish but the other half is pretty decent and dives into what I was expecting to find in this book. Currently I am reading a chapter on analysis of financial statements of companies, which ought to be published every year. I must admit that some metrics might be misleading, for instance if company has got lots of Accounts Receiveable you would think it is good. That means that many other companies or people own money to company but company needs to collect that money. If that value increases and the current assets (cash) does not increase -> that means that company has problems collecting its debt and it is considered to be bad debt. There are many more metrics to analyse and I am really just scratching the surface.

Have you ever traded on stock exchange? Do you have any useful tips?

ESBs and Mule

At work I am creating one application and I am considering to use ESB in future. I am not sure if it is going to be a sensible approach to the problem I am trying to resolve. I was looking the other day on amazon Mule 2.0 book is going to be published soon. There are lots of books on ESBs and I have number of them but they are very generic, talk about message routing, message exchange patterns. ESBs might be a level of complication which we might not need so I will try to establish that. KISS principle will be a driving force but too much KISS also limits as well so it is a balance thing.

The reason I consider Mule is that I think we can free users from "pointless clicking" by automating data exchange between applications. The trick is that I still need to build few applications before I can start thinking about automating data exchange between them. The idea is that every application will have a user interface so that a human being can interrupt process and fix it but in addition every application will have an automated interface for internal inter-application data exchange. I must admit that one problem is also to decide on granuality of applications and services, which ones should be deployed in separate processes and which services should be part of the same application.

The other problem is that some changes might require cooperation with US and them exposing some services via REST or SOAP and they have different set of priorities so to sync all of this might be a challange.

I have seen number of presentation from parleys.com about Mule and ESBs in investment banking and I think I understand more about how it works. We have specific requirements in which we have lots of data exchange (huge files) so not every solution might work out.

JMX and JManage

Since I joined Shopzilla I have been developing one application. As most applications this application has two parts, one is core and one is web application. I wanted to deliver something that is usable as quickly as possible for users. Users are in fact employees of the company so it could be quick and dirty but not much. Users I deal with don't like command like applications and don't have skills to install things like java, python, perl or ruby.

I found a brilliant solution, which has proven to be the right so far. It is JMX. JMX is bit techy but a lot boils down to a frontent application. One is limited in certain way, user interface cannot be as sophisticated as it could be if everything was developed from scratch but the speed at which you can deliver something that works is exceptional.

I have delivered a core and an useable graphical applications after 3 weeks of working. This already provides a business value and Shopzilla is able to monetize on that!

I recommend JManage to everyone it is also brilliant for monitoring of production applications (it was designed to be just that) but can be used for internal applications as user interface is really appealing.

http://www.jmanage.org

Useful Linux commands

http://www.pixelbeat.org/cmdline_pl_PL.html

Finding a jar containing a class

I found a nice script that searches through all of your jar files and finds which jars have a particular class. It is a shell script:

mati@mati-ubuntu:~/.m2/repository$ find . -name *.jar -exec csh -c ' (jar tvf $1 | grep org.springframework.jdbc.UncategorizedSQLException) && echo "======= found in $1" ' '{}' \;

IPod and Podcasts

I am a happy owner of 80GB IPod and I must say that I like it a lot. I use it mainly to listen to my favourite podcasts. ITunes is full of podcast feeds. My favourite podcasts are:
1. BBC Focus Podcast
2. Polskie Radio - Nauka
3. Polskie Radio - Radionowela - Motel w Pol Drogi
4. Software Engineering Radio
5. Bloomberg news
6. BBC's Digital Planet
7. In Our Time with Melvyn Brag (BBC Radio 4)
8. Parleys.com
9. Java Posse
10. Google's Developer Podcast
11. ThoughtWorks Podcast

Scrum

New job comes with new responsibilities but also knowledge. Here at Shopzilla they use Scrum and I must admit that so far I like this agile methodology. We have daily scrums in which we quickly tell each other what we are working on. We plan iteration in so called sprints. A lot of these practices I have been doing before but the whole thing was more chaotic, scrum introduces common sense project management practices worth following. I am still learning Scrum so don't consider to me an expert!

You can listen to this great scrum interview with Roman Pichler. It is worth listening.

http://www.se-radio.net/podcast/2007-06/episode-60-roman-pichler-scrum

Extrapolation

The problem that nettles me is whether it is possible to use extrapolation, aproximation (various kinds) only on historical data from stock market for discret companies to be able to get a yield of 12% each year. Why only on historical data and only on 12%? Well 12% year to year is a lot as long as it is stable. I am reading recently a book on investment on stock markets and one thing is said there is that since its beginning a stock market in the US gave yield of an average 12% year to year. Of course, some years it was 50%, some it was -40% what counts is the average. It must be said that the best online saving account in the uk gives an interest of around 6.50% (HiSaver account) -> see www.fool.co.uk). 6.50% is decent rate but there is tax on top of that, so nett it is about 5%.

I am aware that historical data should not be used as the only source of information that influences stock market prices. As a matter of fact there are many sources of information. For instance for agrocultural companies a very important source of information would be whether next year there will be a draught. The problem is that we need to get lots of semantically well defined data for computer program to be able to reason about the future. For that purpouse we can use SOA and let a computer system collect relevant data from many different sources to be able to reason about the future. Speaking in mathematical language we always want to have a function from now, known point (today) to some not so distant point in the future, lets say next day or a week. That function shape is determinated by many factors and to be able to build it from these factors first we have to have lots of data and then to write an algorithm that calculates this function from known set of data. Shape of the function will change based on current data but historical data will also be taken into account. I am sure many have attempted to write a computer system that would be able to do that. Well that would be my dream. I just want a stable yield of 12% year to year.

Equality in Ruby - == eql? and equal?

The == comparison checks whether two values are equal

eql? checks if two values are equal and of the same type

equal? checks if two things are one and the same object.

How do I remember which is which ... The longer the operator, the more restrictive the test it performs

Example:

irb(main):013:0> val = 17
=> 17
irb(main):014:0> val == 17.0
=> true
irb(main):015:0> val.eql?(17.0)
=> false
irb(main):016:0> val.eql?(17)
=> true
irb(main):017:0> val.equal?(17)
=> true
(written 2006-12-14 16:49:47)