The following Use Cases describe how the ims-ld package for .LRN can be applied in different situations. Some of these Use Cases have been inspired for the experience in the E-LANE project . The ims-ld package for .LRN will have a wide range of capabilities and it could be applied to a wide range of powerful pedagogies and scenarios. Here we explain different Use Cases where this package can be used. The Use Cases doesn't present the detailed diagram about the interactions between the different roles involved, but they can be easily deduced from the given explanation.

The ims-ld package will communicate with different .LRN services, as part of different activities, presenting them in a prescribed order. The ims-ld package allows to visualize in the same window different .LRN services like assessments, calendar, evaluation(gradebook), forums, FAQs, chat, etc. With the ims-ld package the user only has to click the execution window link, and then he/she will be able to visualize all the workflow of the activities designed for him/her without having to go to the concrete links.

With the IMS-LD package can be used to evaluate the users in the unit of learning (using evaluation, for instance), but it also can evaluate them using the contents and activities of the e-learning process, and even tests, that the professor have designed. Therefore the entire educational process is evaluated. The professor can assign tests for some activities, for some contents, for some users, etc. As a particular example of this scenario, several contents can be presented to the students grouped in different activities. The activities are presented to the students in a sequential order and after each activity an assessment associated to its content has to be done. These way the professor can evaluate the students for all the different contents, and also evaluate the content. For example, if the majority of the students fails an exam then it is a signal of a content that could require modification. Moreover, IMS-LD allows to evaluate the process in function of the obtained objectives (learning objectives). The ims-ld package defines overall objectives and objectives for each activity, so an analysis of the obtained objectives can be made with respect to the initial requirements.

The possibility of the ims-ld package of defining personal global properties allows to define a concrete user modeling in the e-learning experience (unit of learning). A user model in ims-ld package can be viewed as a set of global properties for a user. The idea is that a user should follow a particular path in the unit of learning depending on its particular profile. The ims-ld package allows to define concrete sequences along with the contents depending on the user properties and also to show or hide some content inside a document depending on them. As a particular example, in the E-LANE project we are several different partners, and some or them speak Spanish, so at the E-LANE project we have designed different courses in Spanish. Each country has its special form of the Spanish language, and some words doesn't mean exactly the same in all the countries, also some courses can be applied in some countries but not in others. With the use of IMS-LD we can solve this problem, defining a property named country and personalizing each content depending on the country of the user. Therefore, if a word has different meanings in different countries, the system will be show the appropriate word depending on the country property of each user.

The ims-ld package allows to define different paths along with the different activities depending on the result of an evaluation of a homework, task, depending on the grade of an assessment or a on combination of several evaluations. For example, we can define three levels of the student knowledge: low, medium and high. If a students receive a set of evaluations, assessments, etc. and with the tests results the systems detects that they have a low knowledge level, the system, based on the unit of learning design, can detect it and present to the students an easy exercise. Nevertheless, if the tests show that the student has a high knowledge level, then the system presents to the student a more difficult exercise. By this way we are adapting the content to the necessities and knowledge of the students.

Each unit of learning can have a set of prerequisites and a set of objectives. The prerequisites can be considered as the previous related knowledge necessary about a given subject and the objectives can be considered as the future knowledge to acquire. The ims-ld package allows to check if a particular user has the required knowledges (the previous and future ones) using assessments or/and evaluations. This way the system can determine the weak knowledge areas of the students and show them only the knowledges they don't have. This way, for instance, if the student already knows some concepts of the course, we can avoid to show them because it is a waste of time for the students.

A student can repeat the same activity if the obtained results are not the desirable or expected ones. He/She can repeat all the activity or only one part of the it. The repeated activity can consist of assessments, forums, content, FAQ, chat, etc.

A user can select different options during the cycle of the unit of learning, for example, checking a checkbox or fulfiling a text box, and depending on this selection he/she can go trough different paths along the course.

The ims-ld package allows to use a common framework for different pedagogical models. One of the most beneficial techniques in order to learn is the problem based learning, where a problem is given to the students and evaluated by a professor. For example we can apply the Polya model for problem solving. This method has four phases: 1) Understanding the problem 2) Doing a plan 3) Execution of the plan 4) Review and examining the solution. In IMS-LD all of this can be described. There could be infinite possibilities for applying this model in IMS-LD. This example uses the Polya model appliet to a mathematics problem: We have only one play and one act for this example. The act has one learning-structure which shows the different activities in an stablished order. Each phase of the Polya model will have at least one associated activity. 1) Understanding the problem: The activity consists in reading the enunciation of a problem. The problem is presented to the student as a description. Also, there is a resource inside an environment that asks the student the next questions: What are the variables? What are the conditions? Is enough the conditions to determine some variables?, etc. IMS-LD can indicate that only when the user answer these questions he/she can move on to the next step. this will be interpreted in our .LRN package and only when this condition is done the student will go to the next step. 2) Doing a plan: The activity consists of thinking an adequate strategy for solving the problem. To help the student, he/she can consult an environment during the activity that consists of a set of files that contains the theoretical concepts that helps to understand the problem. With the IMS-LD specification, the professor can indicate that only when the student push a specific bottom, then he/she will go to the following step. The ims-ld package deal with this case too. 3) Execution of the plan: This phase has two activities. Both of them use the Evaluation(Gradebook) package. The first activity is for the students, they have to do the solution of the problem and submit it to the system. The second one is for the professors and it is a support activity. They have to grade the submissions and also they provide feedback for the students. 4) Reviewing and examining the solution: The student has to debug his/her answer according to the feedback received by the professor. The professor in the previous phase has given the students the solution and they should extend it to other type of problems. In this phase, the students can access the course materials, use the chats, forums, etc, in order to discuss their ideas among them, and finally they have to take an assessment.

The benefits of working with groups of students in order to learn are well known. The ims-ld package allows this approach in several ways. It allows to define different roles which in the execution time will be transformed in different groups. Each group can receive a common problem to solve, being in a common forum, chat, etc. Also, there can be different groups with people of different roles, where each person has to do a different task in order to get the work done, which at the end is discussed by all members of the group.

The ims-ld package allows to produce different ways of Collaborative Learning. For example, it can establish that until a certain group doesn't finish one set of activities, then the following activity will not begin. This can be done thanks to the conditoins of the different acts. It also allows the interaction between people with, for example, the notifications of the Level C of IMS-LD. Also, for the Collaborative Learning, the chat, forums, etc. can be used. For example, in a learning experience, until all the members of a group have not finished reading an on-line text, they cannot start a discussion forum about it.

As a lot of games requires a sequence of activities and interaction between different roles, then some Games could be modeled as IMS-LD, and they could be played using the Player of the ims-ld package

The methodology represented in an IMS-LD file can be reused for other purposes. For example the methodology of a successful course of "Computer Architecture" could be reused in another course of "Communication Software". Although the content of the courses have nothing in common, the methodology can be reused in the sense of the order of the activities, conditions, services that are going to use, etc.

The presented use cases are only a set of examples about some possible applications of the ims-ld package in .LRN, but it is not restricted to this applications. There can be a use case that combines some or all of the ones described above too. For example, a collaborative learning activity, problem based and content personalized e-learning experience with an evaluation of the educational process is possible. Whichever other combinations are also possible. We have tried to represent the more common applications but there are some other applications that can be applied with the ims-ld package and have not been mentioned. In Summary the ims-ld package provides a wide range of possibilities for both teachers and students, and many different and interesting use cases have been exposed.