It seems Omnet++ Inet still has problems with 802.11 mac layer implementation. The problem I face is, throughput decreases to half when the Max Contention Window parameter is set to same value with Min Contention Window. I made the experiment with throughput example supplied in Inet. Simulation environment is set up as 1 AP and 1 Station when cwMinData and cwMaxData is set same value throughput is measured around 2.7 Mbps. Interesting thing is it is same regardless of the value I set (3, 7, 32 …). With 1 AP and 1 Station there shouldn’t be a collision and throughput shouldn’t decrease. I asked forums and reported as bug but still couldn’t find a solution. I guess I’ll be looking for alternative simulation environment, may be ns3?
Upgrading to Mac OS X 10.9 Mavericks breaks OMNET++, some actions required to get it working correctly. Here is the steps that I followed;
- Install latest Xcode 5.0.1 from Mac App Store
- Install command line tools xcode-select –install
- Install macports Mavericks build
- Install gcc version 4.7 via macports
sudo port selfupdate
sudo port install gcc47
sudo port select –set gcc mp-gcc47
After this point you can compile OMNET++ and get working but, I faced problems when running simulations like missing icons/images in simulation. I think Tcl library has issues with Mavericks, in my case it has to reinstall too.
- sudo port install tcl
sudo port install tcllib
- Now, edit configure.user in OMNET++ source directory
TK_LIBS=”-L/opt/local/lib -ltk8.6 -ltcl8.6″
- Now you can follow OMNET++ standard installation instructions.
Last week I read Learning OMNeT++ , the book is published by Packt Publishing which is about popular network simulation software. Book is 102 pages and it is easy to read and follow, it took a few days to go over and finish it. It is available in pdf, epub and Kindle formats which is good.
Book covers OMNET++ IDE, network structure, models, basic and compound modules, simulation environment, evaluation of simulation results and INET framework with example simulations.
It is a good resource to start learning OMNET++. It’d be nice if wireless related topics was included too. If you want to make quick start to OMNET++, I’d recommend reading the book: Learning OMNET++.
I had my pebble watch a few weeks ago and actively using it. In general watch is really good. However it has some issues. Some pebble owners face oily looking screen but I was lucky to get working one. Battery life is 5 days in average, changing 4 to 7 days with usage. Most of the iOS notifications appear on watch except whatsapp (most important app for me) and watch doesn’t use unicode encoding. Caller ID is a really big problem, already memorised most popular phone numbers in my address book, thanks to Pebble !!!
One of the most important network conferences WCNC 2014 will be held in Istanbul. Our plan is to attend conference with a paper which we have been working for a while if we finalize it. I hope I’d manage to meet important people in wireless networks.
This is the second part of the my post on Spring & JEE first impressions. This part is a quick glance to development environments. Netbeans 7.2 is used for JEE and IntelliJ IDEA 12 is used for Spring Framework. IntelliJ IDEA is a general purpose IDE for Android, Java, J2ME, JEE, Spring ..etc.
Netbeans provides best integration with Java EE technology stack, it handles configuration automatically and helps developers with suggestions. Whenever an entity class is annotated Netbeans checks for persistent unit, if not available it makes suggestions for persistence unit.
Also, It has also code generators for entity classes, especially ones from database tables. It generates necessary classes and named JPA queries.
Netbeans comes with Glassfish bundle, application can be deployed to the app server through one click. Everything is handled by IDE.
If you are on Spring Framework which is generally developed by Eclipse, you have to generate maven configuration and related dependencies for spring and sub spring projects. After having Spring libraries, there are configurations need to be set up for the application. Sometimes its annoying to define datasource, transactions, beans … etc. At this point IntelliJ IDEA helps to handle configurations easily. It can detect enabled modules in applications.
Syntax highlighting is amazing, it is available in almost any files, java, xml … etc. It can suggest which actions to take against problems.
No doubt that ORM is a power tool for managing data through OOP manner however, some times specific OOP queries needed. But, writing and testing these queries a little harder when compared to SQL since, there are no ORM manager. IntelliJ IDEA helps it with built in console for executing object queries inside the IDE without deploying application. The most amazing tool in the IDE (personal opinion).
This post is about comparing IDEs than technology stack. Next parts will focus on more related to technologies like Persistence, MVC, JSF and Security on Spring and JEE.
I’ve worked with Java Enterprise Edition 5 in a real enterprise environment but never had a chance for Java EE 6. Java EE is getting better in every release Java EE 7 is on the way and supports from companies increasing every year. A few months a go I started to use Spring Framework as my primary web framework for Java, It is too early to make comparisons but I can tell my first impressions on these two technologies.
Both two are open source and have a big community to support enterprise application development, spring seems more developers than JEE for now. Things that I like JEE ecosystem is , all components are developed (lead) by one company. The language itself Java, framework JEE, IDE Netbeans even database MySQL and the application server Glassfish. It provides really nice integration. Spring has STS but never used it and I haven’t seen anyone using it either. One thing that I don’t like Spring is configurations…. There are uncountable XML files and tags, in general I lost my self in it. This gap can be closed by Intellij IDEA which has better support for Spring than others. I’ll try to share my thoughts here for Spring + Intellij IDEA combination.
“Foundations of Security” kitabının arkasından okumaya başladığım “Secure Java For Web Application Development” kitabın sonua geldim. Kitap 300+ sayfa anlatılan içerik 100 sayfaya rahat sığar. Bazı konular çok kez tekrar edilmiş. Konular örnek bir uygulama üzerinden anlatılmış, yeni başlayanlar için oldukça ideal. Kitaptan beklediğim ve ismindede geçen Java’yı görmekti, malesef Java’dan pek fazla bahsedilmiyor ve hatta Java Enterprise’ın ismi bile geçmiyor desem abartmış olmam. Çok detaylı teknik bilgi bulmak zor, bu yüzden genel bir kesime hitap ediyor.