Tag: AHP PHP

AHP-OS Update July 2019

After many hours of work, I released a new version of my free AHP online system AHP-OS. The whole package was restructured in preparation to make it available for an installation on any other web server.

Beside a lot of under-the-hood improvements, the software now runs under php 7.2 and sqlite 3.10. It should be faster than before. I also prepared to switch from sqlite to MariaDB 10 SQL database, as the number of users is increasing steadily, and the sqlite file getting larger and larger.

New Features

For you, as a user, an additional feature has been implemented. You can now close a project for further pairwise comparison inputs. Once closed, participants can no longer input data.

Message for participants, when the project is closed

The project status can be toggled between open/closed in the project administration menu.

Project Administration Menu: additional button Toggle Project Status on the right.

The project status is shown in your AHP project list as 1 – open, 0 – closed.

As a project author you can now also start pairwise comparisons directly from the Project administration Menu.

Start pairwise comparisons for your project with PWC Input.

New Web Address

AHP-OS can now be easily accessed via the subdomain ahp.bpmsg.com . The package was moved from bpmsg.com/academic to bpmsg.com/ahp. If you have bookmarked the old address, you will be automatically redirected.

AHP online software – how it was implemented

When I was asked just now in an e-mail, how my AHP online software operates,   I realized that I have never published a description about it. Therefore, here a short summary:

The AHP-OS software implementation is based on my AHP excel template. I have published one paper about it in 2013. All mathematical formulas used, are shown in this conference paper or in the excel template manual on the last 2 pages. The online version is realized in PHP, using OOP (object oriented programming), running on a Linux server.

The core module is the ahp class. It contains the routines to fill the decision matrix from the pairwise comparisons, to find the dominant eigenvalue using the power method, and to calculate the consistency ratio.

A second important class is the hierarchy class. It translates the text file – defining the hierarchy – into a hierarchical data array. When I implemented the software, I wanted to get a flexible tool, which can be used for all kind of hierarchical problems. This was actually more difficult than the implementation of all mathematical calculations, especially under the aspect of safety and malicious online attacks. The feature also differentiates the online version from the excel implementation. The excel template cannot handle hierarchies at all.

The third important class implements the database and its management. I use SQL with either sqlite or mysql drivers. There are 4 tables:

  • one for user management (registration, password, etc.),
  • one for projects (hierarchy data, description, session code etc.),
  • one for pairwise comparisons (participants, judgments etc.) and
  • one for handling alternatives.

The rest of classes contain supporting functions, like html in/output, excel download and consolidation for group results. I use a basically two open source packages, phpMailer and phpGraphlib, the rest is all realized by myself from scratch.

Please consider a donation, it will help me to maintain the website and program.

Update 2017: AHP-OS software implementation (pdf)

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