Executive SummarySeveral researchers have studied the impact of collaboration between the learners on their cognitive levels, but few studies have been carried out on the impact of collaboration between the teachers. The aim of our research is to study the effects on the knowledge levels of learners of collaborative construction of learning objects created by the teachers. More precisely, the objective is to conceive a distance learning environment that takes into account many concepts and strategies. Among the tasks assigned to our research team is to study the effects of collaboration among learners on the one side and among teachers in the other side. In previous work, we have studied the impact of collaborative learning on the cognitive profile of learners. In this work, we focused on the impact of collaboration among teachers on both teachers and learners. The aim of this paper is to present a collaborative authoring system called SAC (which is the French acronym of Système Auteur Collaboratif). This is designed to be used in an academic environment. Moreover, it can be used by any academic institution adopting the LMD (Licence-MasterDoctorate) regime. Its principal feature is that it takes into account collaboration among teachers for construction of learning objects. In this case, teachers collaborate to build common products. They discuss and coordinate their efforts to build pedagogical content that reflects all their points of view. Through this system, the teachers can put their courses online in various formats (lessons, tutorials, presentations, etc.) and students can download lessons, self-assess, and communicate with their colleagues.We used a certain number of criteria for making the collaboration task more efficient. These criteria are used by a search tool of co-authors, which is a part of SAC system. Among these criteria are the behavioral profile and the expertise area of teachers. The co-author search tool is like a search engine but it is used for searching authors in order to perform collaborative tasks.The use of this system overcomes the difficulties met by teachers in traditional systems. These difficulties are mainly related to the lack of tools, and assistance means facilitating their tasks during the preparation of their learning objects. In fact, this system has many features for the organization of learning objects and the facilitation of the courses preparation. These courses are those of the Licence degree.SAC was implemented and tested by a sample of university students and teachers. The aim was to know the attitude of these actors toward the system and the content of the courses that are built collaboratively. The obtained results showed that the teachers enjoyed using the system. They were very satisfied with the main components of SAC, suchMaterial published as part of this publication, either on-line or in print, is copyrighted by the Informing Science Institute. Permission to make digital or paper copy of part or all of these works for personal or classroom use is granted w...

In this paper, we present three strong edge stopping functions for image enhancement. These edge stopping functions have the advantage of effectively removing the image noise while preserving the true edges and other important features. The obtained results show an improved quality for the restored images compared to existing restoration models.