Article Network

OpenCV: Image Processing using Morphological Filters

by Robert Laganière | May 2011 | Cookbooks Open Source

OpenCV (Open Source Computer Vision) is an open source library containing more than 500 optimized algorithms for image and video analysis. Since its introduction in 1999, it has been largely adopted as the primary development tool by the community of researchers and developers in computer vision. OpenCV was originally developed at Intel by a team led by Gary Bradski as an initiative to advance research in vision and promote the development of rich, vision-based CPU-intensive applications.

In this article by Robert Laganière, author of OpenCV 2 Computer Vision Application Programming Cookbook, we will cover:

  • Eroding and dilating images using morphological filters
  • Opening and closing images using morphological filters
  • Detecting edges and corners using morphological filters
Read OpenCV: Image Processing using Morphological Filters in full

OpenCV: Segmenting Images

by Robert Laganière | June 2011 | Cookbooks Open Source

OpenCV (Open Source Computer Vision) is an open source library containing more than 500 optimized algorithms for image and video analysis. Since its introduction in 1999, it has been largely adopted as the primary development tool by the community of researchers and developers in computer vision. OpenCV was originally developed at Intel by a team led by Gary Bradski as an initiative to advance research in vision and promote the development of rich, vision-based CPU-intensive applications.

In the previous article by Robert Laganière, author of OpenCV 2 Computer Vision Application Programming Cookbook, we took a look at image processing using morphological filters.

In this article we will see how to segment images using watersheds and GrabCut algorithm.

Read OpenCV: Segmenting Images in full

Openfire: Effectively Managing Users

by Mayank Sharma | October 2009 | Java Open Source

In this article by Mayank Sharma, you will learn how to effectively manage users in Openfire.

The difference between a hassled always-on-the-job admin and an admin who has plenty of time to dress for a lovely date in the evening, is how effectively they manage their users. As any admin knows, managing users is one thing, but managing users effectively takes something special—from both you and the server software. In this article, I'll show you some tips and tricks that you can use to become a happy-go-lucky system admin. But finding a beautiful date is beyond the scope of this book!

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OpenGL 4.0: Building a C++ Shader Program Class

by David Wolff | August 2011 | Cookbooks Open Source Web Graphics & Video

If you are using C++, it can be very convenient to create classes to encapsulate some of the OpenGL objects. A prime example is the shader program object. In this recipe by David Wolff, author of OpenGL 4.0 Shading Language Cookbook, we'll look at a design for a C++ class that can be used to manage a shader program.

Read OpenGL 4.0: Building a C++ Shader Program Class in full

OpenGL 4.0: Using Uniform Blocks and Uniform Buffer Objects

by David Wolff | August 2011 | Cookbooks Open Source Web Graphics & Video

If your OpenGL/GLSL program involves multiple shader programs that use the same uniform variables, one has to manage the variables separately for each program. Uniform blocks were designed to ease the sharing of uniform data between programs. In this article by David Wolff, author of OpenGL 4.0 Shading Language Cookbook, we will create a buffer object for storing the values of all the uniform variables, and bind the buffer to the uniform block. Then when changing programs, the same buffer object need only be re-bound to the corresponding block in the new program.

Read OpenGL 4.0: Using Uniform Blocks and Uniform Buffer Objects in full

OpenID: The Ultimate Sign On

by Gurudutt Talgery | February 2008 | Content Management Drupal Open Source

Remembering all login IDs and passwords for all the Internet forums and communities that you are part of, is indeed an onerous task and one more registration for a new site seems like one too many. We have all tried to get around these problems by jotting down passwords on pieces of paper or sticking notes to our terminal – all potentially dangerous practices that defeat the very purpose of keeping a digital identity secure.

Gurudutt Talgery shows a solution to this problem in this article. A solution, which is free, non-proprietary, open standards based, extensible, community-driven framework with Open Source libraries and helpful tutorials to get you on board, called OpenID.

Read OpenID: The Ultimate Sign On in full

Opening up to OpenID with Spring Security

by Peter Mularien | May 2010 | Java Open Source Web Development

OpenID is a very popular form of trusted identity management that allows users to manage their identity through a single trusted provider. This convenient feature provides users with the security of storing their password and personal information with the trusted OpenID provider, optionally disclosing this personal information upon request. Additionally, the OpenID-enabled website can have confidence that the users providing OpenID credentials is who they say they are.

In this article by Peter Mularien, author of the book Spring Security 3, we will:

  • Learn to set up our own OpenID in less than five minutes
  • Configure the JBCP Pets website with a very rapid implementation of OpenID
  • Learn the conceptual architecture of OpenID and how it provides your site with trustworthy user access
  • Implement OpenID-based user registration
  • Experiment with OpenID attribute exchange for user profile functionality
Read Opening up to OpenID with Spring Security in full

OpenLayers: Overview of Vector Layer

by Erik Hazzard | April 2011 | Beginner's Guides Open Source

Get exclusive offers on Open Source Graphic Application and Library books through out this month. For more information click here.

OpenLayers is a powerful, community driven, open source, pure JavaScript web-mapping library. With it, you can easily create your own web map mashup using WMS, Google Maps, and a myriad of other map backends.

In this article by Erik Hazzard, author of OpenLayers 2.10 Beginner's Guide, we will discuss what the Vector Layer class is and see how it works.

Read OpenLayers: Overview of Vector Layer in full

OpenSceneGraph: Advanced Scene Graph Components

by Rui Wang Xuelei Qian | December 2010 | Beginner's Guides Open Source

In this article by Rui Wang and Xuelei Qian, authors of OpenSceneGraph 3.0: Beginner's Guide, we will learn:

  • How to create geometries as billboards in the scene?
  • How to display 2D and 3D texts in the scene?
  • How to design a particle system and animate it?
  • How to cast shadows onto scene objects?
  • The theory and implementation of special effects
Read OpenSceneGraph: Advanced Scene Graph Components in full

OpenSceneGraph: Managing Scene Graph

by Rui Wang Xuelei Qian | December 2010 | Beginner's Guides Open Source

Scene graph is a hierarchy graph of nodes representing the spatial layout of graphic and state objects. It encapsulates the lowest-level graphics primitives and state combined to visualize anything that can be created through a low-level graphical API. OpenSceneGraph has leveraged the strength of scene graph and developed optimized mechanisms to manage and render 3D scenes, thus allowing the developers to use simple but powerful code in a standard way, in order to realize things such as object assembling, traversal, transform stack, culling of the scene, level-of-detail management, and other basic or advanced graphics characteristics.

In this article by Rui Wang and Xuelei Qian, authors of OpenSceneGraph 3.0: Beginner's Guide, we will cover the following topics:

  • Understanding the concept of group nodes and leaf nodes
  • How to handle parent and child node interfaces
  • Making use of various nodes, including the transformation node, switch node, level-of-detail node, and proxy node
  • How to derive your own nodes from the basic node class
  • How to traverse the scene graph structure of a loaded model
Read OpenSceneGraph: Managing Scene Graph in full

OpenSceneGraph: Methods for Improving Rendering Efficiency

by Rui Wang Xuelei Qian | February 2011 | Beginner's Guides Open Source

Real-time rendering is in quite demand in computer science today, and OpenSceneGraph, being one of the best 3D graphics toolkits, is being used widely in the fields of virtual reality, scientific visualization, visual simulation, modeling, games, mobile applications, and so on. Although you can use the powerful OpenSceneGraph, which is based on the low-level OpenGL API, to implement applications that simulate different environments in the 3D world, developing picture-perfect applications is easier said than done.

In this article by Rui Wang and Xuelei Qian, authors of OpenSceneGraph 3.0: Beginner's Guide, we will learn:

  • Different ways to improve rendering performance, by modifying and sharing geometries and textures
  • The dynamic paging mechanism and its utilization in handling huge datasets
Read OpenSceneGraph: Methods for Improving Rendering Efficiency in full

OpenStreetMap: Gathering Data using GPS

by Jonathan Bennett | September 2010 | Open Source

OpenStreetMap is a diverse project with hundreds of thousands of people contributing data and making use of it in different ways. As a result, many of the resources that mappers have created and use are scattered around the Internet, but the project data and much of the documentation is hosted at openstreetmap.org, on servers operated by the OpenStreetMap Foundation.

As a crowdsourced project, OpenStreetMap is heavily reliant on having an active community participate in the project, and there are probably as many tools and websites aimed at allowing mappers to communicate and collaborate as there are for mapping and using the data. Mappers have created many different ways of sharing information, based on personal preference and the kind of information involved.

In this article by Jonathan Bennett, author of the book OpenStreetMap, we'll look at the tools and techniques used by the OpenStreetMap community to gather data using GPS, and upload it to the website, including:

  • What the Global Positioning System is, and how it works
  • How to set up your GPS receiver for surveying
  • How to get the best signal, and more accurate positioning
  • How to tell a good GPS trace from a bad one
  • Ways of ensuring your survey is comprehensive
  • Other ways of recording information while surveying

We'll also look at a couple of ways of gathering information without needing a GPS receiver.

Read OpenStreetMap: Gathering Data using GPS in full

OpenX Advanced Reports

by Murat Yilmaz | March 2010 | Open Source

In this article series by Murat Yilmaz, author of OpenX Ad Server: Beginner's Guide, we will learn how to provide every tool to efficiently analyze the performance of websites, website zones, advertisers, campaigns, and banners. We will learn how we can get such statistics online. Then, we will investigate how we can export the data into a spreadsheet such as in Excel and analyze it with a real example.

Here, we shall learn:

  • How to view advertisers and campaign statistics
  • How to export data to Excel for further analysis
  • Types of advanced OpenX reports
  • How to retrieve advertising analysis reports using Excel

Read Reports and Statistics in OpenX Ad Server.

Read OpenX Advanced Reports in full

Optimizing Lighttpd

by Andre Bogus | July 2009 | Linux Servers Open Source

This article written by Andre Bogus will help us make Lighttpd work even faster. Before we start optimizing our Lighttpd installation, there are some things to consider such as where is Lighttpd going to run?

The most tested system with perhaps the most optimized backend is Linux. So if we need to squeeze every little request per second out of a server, it is a sure guess. In fact, apart from Linux, all systems except Windows are quite capable of delivering good performance.

Read Optimizing Lighttpd in full

Optimizing Magento Performance — Using HHVM

by Mathieu Nayrolles | May 2014 | e-Commerce Open Source Web Development

This article is written by Mathieu Nayrolles, the author of Magento Performance Site Optimization. HipHop Virtual Machine (HHVM) is the cornerstone of the PHP processing stack of Facebook and is currently able to increase the number of requests handle by a server by 9. It is open source and you can download it on GitHub.

Read Optimizing Magento Performance — Using HHVM in full

Optimizing Performance

by Kristina Cutura | July 2013 | Cookbooks Enterprise Articles

This article by Kristina Cutura, author of Advertising on Google: The High Performance Cookbook, will provide tips on improving relevance, Quality Scores, and ROI. The most successful advertisers continuously refine and optimize their campaigns to keep them profitable. Your initial keywords and ads will need to be regularly updated, paused, and refined to stay on top of the latest trends in your market. Also, you'll need to adjust bids and other settings to keep on target with your goals such as a specific ad position or CPA.

Read Optimizing Performance in full

Optimizing Programs

by Rehan Zaidi | May 2013 | Cookbooks Enterprise Articles SAP

In this article by Rehan Zaidi author of SAP ABAP Advanced Cookbook, we will see recipes related to program optimization. We will look at:

  • Using transaction SAT to find problem areas

  • Creation of secondary indexes in database tables

  • Adding hints in SELECT clause

  • Secondary indexes for internal tables

  • Hashed table for single read access

  • Replacing for all entries construct with Ranges

An entire description of the topic constitutes a book by itself. However, we will see some useful and important techniques, as well as some new tools and concepts that are important for developers for program optimization. There are two main techniques—optimizing database statements, particularly SELECT statements and the optimizing ABAP code particularly internal table's access. We will see useful recipes related to both the optimization of database statements as well as internal tables.

We will start with some general rules necessary for optimization. We will start with a recipe showing the usage of transaction SAT for measuring performance of report programs. Then, we will see in detail the steps required in creating secondary indexes for database tables in order to boost performance of queries used in the concerned program. We will then see how hints may be used in programs within SELECT statements, so that a particular index may be used by the system. Finally, we will see how the FOR ALL ENTRIES construct may be replaced with ranges table. The usage of hashed internal tables as well as the new concept of secondary indexes for internal tables will be discussed in separate recipes.

For this article, I assume that the reader has basic knowledge of SELECT statements and database concepts and internal tables, as well as basic optimization techniques. For the better understanding of the information in this article, the reader should know which database would be used in his or her project and know some tricks specific to the database.

Before starting with the recipes, let us see some rules for program optimization:

  • Do not use asterisk (*) in SELECT statements. It means not to select unnecessary columns from database.

  • Do not use nested SELECT statements. Rather use subqueries or inner joins.

  • Create views when multiple tables' data is required.

  • Appropriate and complete WHERE clause conditions should be written.

  • Using FOR ALL ENTRIES within SELECT statements when multiple tables are involved. Also check that the FOR ALL ENTRIES tables are not empty. Otherwise, all records in the underlying table will be accessed that will drastically affect the performance.

  • Using Aggregate functions within SELECT clause such as AVG, MIN, MAX, COUNT(DISTINCT col), and COUNT(*) rather than calculating them yourselves in programs.

  • Avoiding SELECT or SELECT SINGLE within a loop.

  • Usage of hashed tables where a single record within the table is to be searched.

  • Usage of secondary index for internal tables.

For more examples of the previously discussed items, see the Tips and Tricks screen of transaction SAT. For doing so, you need to call transaction SAT. Then press the button on the toolbar. Using transaction

 

Read Optimizing Programs in full

Optimizing your MySQL Servers' performance using Indexes

by Daniel Schneller Udo Schwedt | June 2010 | MySQL Web Development

In this article series by Daniel Schneller and Udo Schwedt, authors of MySQL Admin Cookbook, we will cover:

  • Adding indexes to tables
  • Adding a fulltext index
  • Creating a normalized text search column
  • Removing indexes from tables
  • Estimating InnoDB index space requirements
  • Using prefix primary keys
  • Choosing InnoDB primary key columns
  • Speeding up searches for (sub)domains
  • Finding duplicate indexes
Read Optimizing your MySQL Servers' performance using Indexes in full

Oracle 11g Streams: RULES (Part 1)

by Ann L. R. McKinnell | January 2010 | Oracle

In this article series by Ann L.R. McKinnell and Eric Yen, we will learn all about rules in Oracle 11g Streams. We will discuss the rule components, how to go about creating our own rules and rules based transformations. We will also highlight some of the most important things we need to know while working with rules.

Read Oracle 11g Streams: RULES (Part 1) in full

Oracle 11g Streams: RULES (Part 2)

by Ann L. R. McKinnell | January 2010 | Oracle

In this article series by Ann L.R. McKinnell and Eric Yen, we will learn all about rules in Oracle 11g Streams. We will discuss the rule components, how to go about creating our own rules and rules based transformations. We will also highlight some of the most important things we need to know while working with rules. Read Oracle 11g Streams: RULES (Part 1) here.

Read Oracle 11g Streams: RULES (Part 2) in full
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