Hybrid is an app development approach where only a bare minimum shell of the app is developed using native programming language and most of the app logic is implemented using web technologies (HTML5, CSS3, and various Java Script libraries). Basically, the native shell provides an embedded web browser or container to  load the HTML-based app UI. Hybrid approach is becoming a popular and faster way to reach mobile users across various platforms as most of the app code can be shared across platforms. Although the user experience of hybrid apps is not as intuitive as native, this approach is the only economically sensible option for existing web development organizations to reach the mobile users without significant investment on different mobile platforms.

The most widely used framework for hybrid app development is PhoneGAP which provides the native shell for most of the mobile platforms available now. The key component of the PhoneGAP framework is the Apache Cordova interface – a java script library for accessing various device features: location, local storage etc. PhoneGAP provides a uniform Cordova java script interface for all supported platforms; therefore, HTML based apps can use the same code for all platforms.  Following figure shows how the code of a hybrid app is shared across two different platforms.

 

hybrid_app

 

Ground truth images are essential for the evaluation of object detection or background subtraction techniques. Now what is a ground truth image? Let’s consider a video frame captured using a fixed camera where some objects are static while some are moving. A ground truth image corresponding to this image labels the static and moving parts with two different labels. Usually, white pixels are used for moving objects and black pixels for static pixels. The goal of an object detection technique is to produce detection image close to the ground truth image. To compare the performance of two or more object detection techniques, detection images are compared with the corresponding ground truth images. Most standard datasets come with ground truth images for the test sequences. However, the availability of ground truth images is not uniform across all datasets. For example, some datasets provide ground truth image for just one test frame only while some other datasets provide for all video frames. On the other hand, if you want to want to evaluate performance on your own datasets, there would be no ground truth images at all. A technique to manually generate the ground truth image for a video frame is explained below. Continue reading

Want to quickly share some source codes or a project with the developer community? Free cloud repositories (e.g., GitHub, BitBucket etc.) are the possible alternatives. Obviously, you can use one of these repositories from the very beginning of your project; however, until you are ready to share, you may keep the repository private or don’t commit to the cloud. For instance, GitHub uses Git as the underlying version control system and supports unlimited public repositories for free.  A comprehensive tutorial on that can be found here.

Following simple steps just show how to quickly share an existing project codes on GitHub:

  1. Create a free account on GitHub.
  2. Create a repository for the project you want to share.
  3. It’s a good practice to include a readme file and a license file.
  4. Note down the https clone URL of the repository.
  5. On your local system, make sure that Git for windows or equivalent software for your platform is installed.
  6. Designate a local directory where you want to keep all your local repositories (e.g., C:\GitRepos).
  7. Launch Git Bash from this directory. On window Git Bash appears in the context menu.
  8. From Git Bash type the following command which will create a new directory for the repository with a local copy of the repository: git clone [clone URL obtained earlier].
  9. From Git Bash navigate inside the repository directory: cd [repository directory]
  10. From windows explorer copy all your project files inside the repository directory.
  11. From Git Bash type the following command which will add all file to the staging area of the local repository: git add .
  12. From Git Bash type the following command which will commit the changes to the local repository: git commit –m “check-in comment”
  13. From Git Bash type the following command which will publish or push the local changes to the public repository: git push -u origin master
  14. You are done!

 

DZone Refcardz series has 6 reference cards relating to various agile methodologies and practices. These might be useful for high-level overview and quick reference:

  • Agile Adoption: Improving Software Quality (link)
  • Agile Adoption: Reducing Cost (link)
  • Agile Adoption: Decreasing time to market (link)
  • Scrum (link)
  • Getting Started with Lean Software Development (link)
  • Getting Started with Kanban for Software Development (link)

There are also few online agile glossaries which are very comprehensive: